Uppsala, Sweden

The Swedish University of Agricultural science is a university in Sweden. Although its head office is located in Ultuna, Uppsala, the university has several campuses in different parts of Sweden, the other main facilities being Alnarp in Lomma Municipality, Skara, and Umeå. Unlike other state owned universities in Sweden, it is funded through the budget for the Ministry for Rural Affairs.The university has four faculties: Faculty of Landscape Planning, Horticulture and Agricultural science, Faculty of Natural Resources and Agriculture science, Faculty of Veterinary Medicine and Animal Science and Faculty of Forest science. SLU had in 2012 3080 full-time staff, 3935 full-time students, 714 research students and 241 professors.In the 2007 Academic Ranking of World Universities, SLU was ranked in 5-9 place in Sweden, 81-123 in Europe and 203-304 in the world. Wikipedia.

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Swedish University of Agricultural Sciences | Date: 2015-02-11

A PISTON FOR COLD-CHAMBER INJECTION MACHINES comprising a support (2) and an external body (3) with a sealing ring (5), joined by a bayonet lock ring (6) independent of the external body (3) and divided into two parts (6a) fitted onto a groove (21) in the support (2) and connected by long screws (7) inserted into threaded holes (61). The piston preferably includes a spring bush (4) as a part that adjusts to the container, independent of the external body (3) and of the bayonet lock ring (6), under which a conical spring ring (8) is included which exerts pressure on the two parts that form the bush (4), tending to expand the same. The piston also includes alternating transverse grooves (81) along the edges thereof for receiving conical metal tips (9) inserted through holes (63) in the bayonet lock ring (6).

Swedish University of Agricultural Sciences | Date: 2015-02-18

System for placing elements in an orderly fashion, which comprises a conveyor belt (1) variable in length that projects or retracts itself to convey and deposit elements; a separator (3) for selecting an active container and separating at least the active container from a plurality of stacked containers, thus creating a gap that enables the insertion of the conveyor belt (1). The separator (3) and the conveyor belt (1) are coordinated such that, the conveyor belt (1) is designed to vary in length by either projecting or retracting itself as the elements pass from the conveyor belt (1) to the active container

Swedish University of Agricultural Sciences | Date: 2016-09-21

A device for capturing optical information configured for being installed in a recess of an exterior surface of a vehicle, comprising at least an imaging means configured for obtaining optical information of the surroundings of the vehicle. The imaging means are movable between an operating position and a non-operating position, wherein in the non-operating position the imaging means is able to be located in the recess of the vehicle. The device also comprises a protective cover configured for being able to cover the opening of the recess when the imaging means is in an operating position outside the recess.

Swedish University of Agricultural Sciences | Date: 2016-07-29

A circuit (4) for establishing a desired impedance value for a radio antenna (5) comprising a transistor (3) having an input (8) and an output terminal (6), and a printed radio frequency transformer comprising a first (1) and a second inductor (2), both inductors (1, 2) having a coupling factor value, and having a first and a second terminal (11, 12; 21, 22). The first terminal (11) of the first inductor (1) is adapted for connecting a radio antenna (5). The input terminal (8) of the transistor (3) is connected to the second terminal (12) of the first inductor (1), and the output terminal (6) of the transistor (3) is connected to the first terminal (21) of the second inductor (2), so that the desired impedance value (Z_(2)) at the second terminal (22) of the second inductor (2) is determined by the inductance value of the second inductor (2).

Swedish University of Agricultural Sciences | Date: 2016-09-13

A MIMO antenna system for a vehicle comprising first and second monopole antennas, which comprises first, second and third conductors. First and second conductors are electrically connected in parallel, and the third conductor is coupled to the first and second conductors. The first conductor has a height (H1) and thickness (t1) such that the H1/t1 ratio is within 5 to 45 to provide a resonant frequency at a first LTE frequency band. The second conductor has a height of 30%-60% H1 to provide a resonant frequency at a second LTE frequency band. The third conductor provides resonant frequencies at third and fourth LTE frequency bands, and having an electrical length such that the coupling level of the third conductor with respect to first and second conductors in the third and fourth LTE frequency bands is greater than 10 dB.

Soler C.C.L.,CNRS Center of Evolutionary and Functional Ecology | Proffit M.,Swedish University of Agricultural Sciences | Bessiere J.-M.,National Graduate School of Chemistry, Montpellier | Hossaert-Mckey M.,CNRS Center of Evolutionary and Functional Ecology | Schatz B.,CNRS Center of Evolutionary and Functional Ecology
Ecology Letters | Year: 2012

The dioecious Mediterranean fig, Ficus carica, displays a unique phenology in which males sometimes bloom synchronously with females (in summer), and sometimes not (in spring). Ficus carica is engaged in an obligatory mutualism with a specific pollinating wasp, which reproduces only within figs, localising them by their specific scents. We show that scents emitted by male figs show seasonal variation within individual trees. Scents of summer male figs resemble those of the co-flowering females, and are different from those of the same male trees in spring, when female figs are absent. These differences hold even if only compounds electrophysiologically active for pollinators are considered. The similar scents of summer males and females may explain why the rewardless females are still pollinated. These results offer a tractable model for future studies of intersexual chemical mimicry in mutualistic pollination interactions. © 2012 Blackwell Publishing Ltd/CNRS.

Landberg R.,Swedish University of Agricultural Sciences | Naidoo N.,National University of Singapore | Van Dam R.M.,National University of Singapore
Current Opinion in Lipidology | Year: 2012

Purpose of Review: Endothelial dysfunction plays an important role in development and progression of atherosclerosis and may also contribute to the pathogenesis of type 2 diabetes. This review summarizes recent findings on the effects of vitamin D, antioxidant vitamins, polyphenols, polyphenol-rich foods, dietary component combinations and healthy diets on endothelial function. Recent Findings: Dietary patterns rich in fruit, vegetables, fish and nuts appear to have beneficial effects on endothelial function. With regard to specific foods, cacao and green tea consumption have been associated with improvement in endothelial function and this seems to be due to their flavan-3-ol (catechins and epigallocatechin gallate) content. The evidence for beneficial effects of other foods such as citrus fruit, apples and red wine is less consistent. Recent studies have also suggested beneficial effects of vitamin D and anthocyanins on endothelial function and have provided more insight into potential mechanisms underlying the effect of diet on endothelial function. Summary: The currently available evidence supports beneficial effects of various dietary compounds on endothelial function. However, in order to obtain strong evidence for relevant health effects that can be used for specific dietary recommendations, more long-term studies using well characterized diets/supplements in a large number of individuals are needed. © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins.

Pacurar D.I.,Umeå University | Perrone I.,Umeå University | Perrone I.,Swedish University of Agricultural Sciences | Bellini C.,Umeå University | Bellini C.,French National Institute for Agricultural Research
Physiologia Plantarum | Year: 2014

Vegetative propagation of economically important woody, horticultural and agricultural species rely on an efficient adventitious root (AR) formation. The formation of ARs is a complex genetic trait regulated by the interaction of environmental and endogenous factors among which the phytohormone auxin plays an essential role. This article summarizes the current knowledge related to the intricate network through which auxin controls adventitious rooting. How auxin and recently identified auxin-related compounds affect AR formation in different plant species is discussed. Particular attention is addressed to illustrate how auxin has a central role in the hormone cross-talk leading to AR development. In parallel, we describe the molecular players involved in the control of auxin homeostasis, transport and signaling, for a better understanding of the auxin action during adventitious rooting. © 2014 Scandinavian Plant Physiology Society.

Taylor R.P.,University of Oregon | Spehar B.,University of New South Wales | van Donkelaar P.,University of Oregon | Hagerhall C.M.,Swedish University of Agricultural Sciences
Frontiers in Human Neuroscience | Year: 2011

Fractals have been very successful in quantifying the visual complexity exhibited by many natural patterns, and have captured the imagination of scientists and artists alike. Our research has shown that the poured patterns of the American abstract painter Jackson Pollock are also fractal. This discovery raises an intriguing possibility - are the visual characteristics of fractals responsible for the long-term appeal of Pollock's work? To address this question, we have conducted 10 years of scientific investigation of human response to fractals and here we present, for the first time, a review of this research that examines the inter-relationship between the various results. The investigations include eye tracking, visual preference, skin conductance, and EEG measurement techniques. We discuss the artistic implications of the positive perceptual and physiological responses to fractal patterns. © 2011 Taylor, Spehar, Van Donkelaar and Hagerhall.

Duan L.,Carnegie Institution for Science | Duan L.,National University of Singapore | Dietrich D.,University of Nottingham | Ng C.H.,National University of Singapore | And 5 more authors.
Plant Cell | Year: 2013

The endodermal tissue layer is found in the roots of vascular plants and functions as a semipermeable barrier, regulating the transport of solutes from the soil into the vascular stream. As a gateway for solutes, the endodermis may also serve as an important site for sensing and responding to useful or toxic substances in the environment. Here, we show that high salinity, an environmental stress widely impacting agricultural land, regulates growth of the seedling root system through a signaling network operating primarily in the endodermis. We report that salt stress induces an extended quiescent phase in postemergence lateral roots (LRs) whereby the rate of growth is suppressed for several days before recovery begins. Quiescence is correlated with sustained abscisic acid (ABA) response in LRs and is dependent upon genes necessary for ABA biosynthesis, signaling, and transcriptional regulation. We use a tissue-specific strategy to identify the key cell layers where ABA signaling acts to regulate growth. In the endodermis, misexpression of the ABA insensitive1-1 mutant protein, which dominantly inhibits ABA signaling, leads to a substantial recovery in LR growth under salt stress conditions. Gibberellic acid signaling, which antagonizes the ABA pathway, also acts primarily in the endodermis, and we define the crosstalk between these two hormones. Our results identify the endodermis as a gateway with an ABA-dependent guard, which prevents root growth into saline environments. © 2013 American Society of Plant Biologists. All rights reserved.

Bodeker I.T.M.,Swedish University of Agricultural Sciences | Clemmensen K.E.,Swedish University of Agricultural Sciences | de Boer W.,Netherlands Institute of Ecology | Martin F.,French National Institute for Agricultural Research | And 2 more authors.
New Phytologist | Year: 2014

Summary: In northern forests, belowground sequestration of nitrogen (N) in complex organic pools restricts nutrient availability to plants. Oxidative extracellular enzymes produced by ectomycorrhizal fungi may aid plant N acquisition by providing access to N in macromolecular complexes. We test the hypotheses that ectomycorrhizal Cortinarius species produce Mn-dependent peroxidases, and that the activity of these enzymes declines at elevated concentrations of inorganic N. In a boreal pine forest and a sub-arctic birch forest, Cortinarius DNA was assessed by 454-sequencing of ITS amplicons and related to Mn-peroxidase activity in humus samples with- and without previous N amendment. Transcription of Cortinarius Mn-peroxidase genes was investigated in field samples. Phylogenetic analyses of Cortinarius peroxidase amplicons and genome sequences were performed. We found a significant co-localization of high peroxidase activity and DNA from Cortinarius species. Peroxidase activity was reduced by high ammonium concentrations. Amplification of mRNA sequences indicated transcription of Cortinarius Mn-peroxidase genes under field conditions. The Cortinarius glaucopus genome encodes 11 peroxidases - a number comparable to many white-rot wood decomposers. These results support the hypothesis that some ectomycorrhizal fungi - Cortinarius species in particular - may play an important role in decomposition of complex organic matter, linked to their mobilization of organically bound N. © 2014 New Phytologist Trust.

Bommarco R.,Swedish University of Agricultural Sciences | Marini L.,Swedish University of Agricultural Sciences | Marini L.,University of Padua | Vaissiere B.E.,French National Institute for Agricultural Research
Oecologia | Year: 2012

The relationships between landscape intensification, the abundance and diversity of pollinating insects, and their contributions to crop yield, quality, and market value are poorly studied, despite observed declines in wild and domesticated pollinators. Abundance and species richness of pollinating insects were estimated in ten fields of spring oilseed rape, Brassica napus var. SW Stratos™, located along a gradient of landscape compositions ranging from simple landscapes dominated by arable land to heterogeneous landscapes with extensive cover of semi-natural habitats. In each field, we assessed the contribution of wind and insect pollination to seed yield, seed quality (individual seed weight and oil and chlorophyll contents), and market value in a block experiment with four replicates and two treatments: (1) all flowers were accessible to insects, self and wind pollination, and (2) flowers enclosed in tulle net bags (mesh: 1 × 1 mm) were accessible only to wind and self pollination. Complex landscapes enhanced the overall abundance of wild insects as well as the abundance and species richness of hoverflies. This did not translate to a higher yield, probably due to consistent pollination by honey bees across all fields. However, the pollination experiment showed that insects increased seed weight per plant by 18% and market value by 20%. Seed quality was enhanced by insect pollination, rendering heavier seeds as well as higher oil and lower chlorophyll contents, clearly showing that insect pollination is required to reach high seed yield and quality in oilseed rape. Our study demonstrates considerable and previously underestimated contributions from pollinating insects to both the yield and the market value of oilseed rape. © 2012 Springer-Verlag.

Inderjit,University of Delhi | Wardle D.A.,Swedish University of Agricultural Sciences | Karban R.,University of California at Davis | Callaway R.M.,University of Montana
Trends in Ecology and Evolution | Year: 2011

Plants can release chemicals into the environment that suppress the growth and establishment of other plants in their vicinity: a process known as 'allelopathy'. However, chemicals with allelopathic functions have other ecological roles, such as plant defense, nutrient chelation, and regulation of soil biota in ways that affect decomposition and soil fertility. These ecosystem-scale roles of allelopathic chemicals can augment, attenuate or modify their community-scale functions. In this review we explore allelopathy in the context of ecosystem properties, and through its role in exotic invasions consider how evolution might affect the intensity and importance of allelopathic interactions. © 2011 Elsevier Ltd.

Bassel G.W.,University of Birmingham | Bassel G.W.,University of Nottingham | Gaudinier A.,University of California at Davis | Brady S.M.,University of California at Davis | And 3 more authors.
Plant Cell | Year: 2012

Physiological responses, developmental programs, and cellular functions rely on complex networks of interactions at different levels and scales. Systems biology brings together high-throughput biochemical, genetic, and molecular approaches to generate omics data that can be analyzed and used in mathematical and computational models toward uncovering these networks on a global scale. Various approaches, including transcriptomics, proteomics, interactomics, and metabolomics, have been employed to obtain these data on the cellular, tissue, organ, and whole-plant level. We summarize progress on gene regulatory, cofunction, protein interaction, and metabolic networks. We also illustrate the main approaches that have been used to obtain these networks, with specific examples from Arabidopsis thaliana, and describe the pros and cons of each approach. © 2012 American Society of Plant Biologists. All rights reserved.

Flysjo A.,Arla Foods | Flysjo A.,University of Aarhus | Cederberg C.,Swedish Institute for Food and Biotechnology | Henriksson M.,Swedish University of Agricultural Sciences | Ledgard S.,Agresearch Ltd.
Journal of Cleaner Production | Year: 2012

Two most critical factors to address in environmental system analysis of future milk production are 1) the link between milk and beef production, and 2) the competition for land, possibly leading to land use change (LUC) with greenhouse gas (GHG) emissions and loss of biodiversity as important implications. Different methodological approaches concerning these factors, in studies on environmental impacts of dairy production, sometimes lead to contradictory results. Increasing milk yield per cow is often one of the solutions discussed in order to reduce GHG emissions from milk production. However, when also accounting for other systems affected (e.g. beef production) it is not certain that an increase in milk yield per cow leads to a reduction in total GHG emissions per kg milk. In the present study the correlation between carbon footprint (CF) of milk and the amount of milk delivered per cow is investigated for 23 dairy farms (both organic and conventional) in Sweden. Use of a fixed allocation factor of 90% (based on economic value) indicates a reduction in CF with increased milk yield, while no correlation can be noted when system expansion is applied. The average CF for two groups of farms, organic and high yielding conventional, is also calculated. When conducting system expansion the CF is somewhat lower for the organic farms (which have a lower milk yield per cow, but more meat per kg milk), but when a 90% allocation factor is used, the CF is somewhat higher for the organic farms compared to the high yielding conventional farms. In analysis of future strategies for milk production, it is suggested that system expansion should be applied, in order to also account for environmental impacts from affected systems. Thus, scenarios for milk and meat production should be analysed in an integrated approach in order to reduce total emissions from the livestock sector. How to account for emissions from LUC is highly debated and there is no current shared consensus. Different LUC methods result in significantly different results. In this study, four different LUC methods are applied, using data for organic milk production and high yielding conventional milk production systems in Sweden. Depending on which LUC method was applied, the organic system showed about 50% higher or 40% lower CF compared to the conventional high yielding system. Thus, when reporting CF numbers, it is important to report LUC-factors separately and clearly explain the underlying assumptions, since the method of accounting for LUC can drastically change the results. © 2011 Elsevier Ltd. All rights reserved.

Mondet F.,University of Otago | Mondet F.,French National Institute for Agricultural Research | Mondet F.,Agro ParisTech | de Miranda J.R.,Swedish University of Agricultural Sciences | And 3 more authors.
PLoS Pathogens | Year: 2014

Over the past fifty years, annual honeybee (Apis mellifera) colony losses have been steadily increasing worldwide. These losses have occurred in parallel with the global spread of the honeybee parasite Varroa destructor. Indeed, Varroa mite infestations are considered to be a key explanatory factor for the widespread increase in annual honeybee colony mortality. The host-parasite relationship between honeybees and Varroa is complicated by the mite's close association with a range of honeybee viral pathogens. The 10-year history of the expanding front of Varroa infestation in New Zealand offered a rare opportunity to assess the dynamic quantitative and qualitative changes in honeybee viral landscapes in response to the arrival, spread and level of Varroa infestation. We studied the impact of de novo infestation of bee colonies by Varroa on the prevalence and titres of seven well-characterised honeybee viruses in both bees and mites, using a large-scale molecular ecology approach. We also examined the effect of the number of years since Varroa arrival on honeybee and mite viral titres. The dynamic shifts in the viral titres of black queen cell virus and Kashmir bee virus mirrored the patterns of change in Varroa infestation rates along the Varroa expansion front. The deformed wing virus (DWV) titres in bees continued to increase with Varroa infestation history, despite dropping infestation rates, which could be linked to increasing DWV titres in the mites. This suggests that the DWV titres in mites, perhaps boosted by virus replication, may be a major factor in maintaining the DWV epidemic after initial establishment. Both positive and negative associations were identified for several pairs of viruses, in response to the arrival of Varroa. These findings provide important new insights into the role of the parasitic mite Varroa destructor in influencing the viral landscape that affects honeybee colonies. © 2014 Mondet et al.

Rader R.,Lipman | Reilly J.,Lipman | Bartomeus I.,Swedish University of Agricultural Sciences | Winfree R.,Lipman
Global Change Biology | Year: 2013

If climate change affects pollinator-dependent crop production, this will have important implications for global food security because insect pollinators contribute to production for 75% of the leading global food crops. We investigate whether climate warming could result in indirect impacts upon crop pollination services via an overlooked mechanism, namely temperature-induced shifts in the diurnal activity patterns of pollinators. Using a large data set on bee pollination of watermelon crops, we predict how pollination services might change under various climate change scenarios. Our results show that under the most extreme IPCC scenario (A1F1), pollination services by managed honey bees are expected to decline by 14.5%, whereas pollination services provided by most native, wild taxa are predicted to increase, resulting in an estimated aggregate change in pollination services of +4.5% by 2099. We demonstrate the importance of native biodiversity in buffering the impacts of climate change, because crop pollination services would decline more steeply without the native, wild pollinators. More generally, our study provides an important example of how biodiversity can stabilize ecosystem services against environmental change. © 2013 John Wiley & Sons Ltd.

Cromsigt J.P.G.M.,Swedish University of Agricultural Sciences | Cromsigt J.P.G.M.,Nelson Mandela Metropolitan University | Cromsigt J.P.G.M.,University of Oslo | te Beest M.,Umeå University
Journal of Ecology | Year: 2014

Megaherbivores have been lost from most ecosystems world-wide, and current increases in poaching of rhino and elephant spp. threaten their status in the systems where they still occur. Although megaherbivores are said to be key drivers of ecosystem structure and functioning, empirical evidence is strongly biased to studies on African elephant. We urgently need a better understanding of the impact of other megaherbivore species to predict the consequences of megaherbivore loss. We used a unique 'recolonization experiment' to test how a megagrazer, white rhinoceros, is affecting the structure of savanna grasslands in Kruger National Park (KNP). With a 30-year record of rhinoceros distribution, we quantified how they recolonized KNP following their re-introduction. This allowed us to identify landscapes with high rhino densities and long time since recolonization versus landscapes with low rhino densities that were recolonized more recently but were otherwise biophysically similar. We recorded grassland heterogeneity on 40 transects covering a total of 30 km distributed across both landscapes. We used two proxies of grassland heterogeneity: % short grass cover and number of grazing lawn patches. Grazing lawns are patches with specific communities of prostrate-growing stoloniferous short grass species. Short grass cover was clearly higher in the high rhino impact (17.5%) than low rhino impact landscape (10.7%). Moreover, we encountered ~20 times more grazing lawns in the high rhino impact landscape. The effect of rhino on number of lawns and on short grass cover was similar to the two dominant geologies in KNP, basalt-derived versus granite-derived soils. Synthesis. We provide empirical evidence that white rhinoceros may have started to change the structure and composition of KNP's savanna grasslands. It remains to be tested if these changes lead to other ecological cascading effects. However, our results highlight that the current rhino poaching crisis may not only affect the species, but also threaten the potential key role of this megaherbivore as a driver of savanna functioning. We provide empirical evidence that white rhinoceros may have started to change the structure and composition of Kruger National Park's savanna grasslands. It remains to be tested if these changes lead to other ecological cascading effects. Our results highlight that the current rhino poaching crisis may not only affect the species, but also threaten the potential key role of this megaherbivore as a driver of savanna functioning. © 2014 British Ecological Society.

Philippot L.,French National Institute for Agricultural Research | Philippot L.,University of Burgundy | Hallin S.,Swedish University of Agricultural Sciences
Trends in Plant Science | Year: 2011

Agriculture is an important source of anthropogenic emissions of the greenhouse gases (GHG), methane (CH 4) and nitrous oxide (N 2O), and crops can affect the microbial processes controlling these emissions in many ways. Here, we summarize the current knowledge of plant-microbe interactions in relation to the CH 4 and N 2O budgets and show how this is promoting new gIPCCenerations of crop cultivars that have the potential to mitigate GHG emissions for future agricultural use. The possibility of breeding low GHG-emitting cultivars is a paradigm shift towards sustainable agriculture that balances climate change and food and bioenergy security. © 2011 Elsevier Ltd.

Esbensen K.H.,University of Aalborg | Geladi P.,Swedish University of Agricultural Sciences
Journal of Chemometrics | Year: 2010

Validation in chemometrics is presented using the exemplar context of multivariate calibration/prediction. A phenomenological analysis of common validation practices in data analysis and chemometrics leads to formulation of a set of generic Principles of Proper Validation (PPV), which is based on a set of characterizing distinctions: (i) Validation cannot be understood by focusing on the methods of validation only; validation must be based on full knowledge of the underlying definitions, objectives, methods, effects and consequences-which are all outlined and discussed here. (ii) Analysis of proper validation objectives implies that there is one valid paradigm only: test set validation. (iii) Contrary to much contemporary chemometric practices (and validation myths), cross-validation is shown to be unjustified in the form of monolithic application of a one-for-all procedure (segmented cross-validation) on all data sets. Within its own design and scope, cross-validation is in reality a sub-optimal simulation of test set validation, crippled by a critical sampling variance omission, as it manifestly is based on one data set only (training data set). Other re-sampling validation methods are shown to suffer from the same deficiencies. The PPVare universal and can be applied to all situations in which the assessment of performance is desired: prediction-, classification-, time series forecasting-, modeling validation. The key element of PPV is the Theory of Sampling (TOS), which allow insight into all variance generating factors, especially the so-called incorrect sampling errors, which, if not properly eliminated, are responsible for a fatal inconstant sampling bias, for which no statistical correction is possible. In the light of TOS it is shown how a second data set (test set, validation set) is critically necessary for the inclusion of the sampling errors incurred in all 'future'situations in which the validated model must perform. Logically, therefore, all one data set re-sampling approaches for validation, especially cross-validation and leverage-corrected validation, should be terminated, or at the very least used only with full scientific understanding and disclosure of their detrimental variance omissions and consequences. Regarding PLS-regression, an emphatic call is made for stringent commitment to test set validation based on graphical inspection of pertinent t-u plots for optimal understanding of the X-Y interrelationships and for validation guidance. QSAR/QSAP forms a partial exemption from the present test set imperative with no generalization potential. © 2010 John Wiley & Sons, Ltd.

Schneider S.C.,Norwegian Institute for Water Research | Kahlert M.,Swedish University of Agricultural Sciences | Kelly M.G.,Bowburn Consultancy
Science of the Total Environment | Year: 2013

Eutrophication and acidification are among the major stressors on freshwater ecosystems in northern Europe and North America, but possible consequences of interactions between pH and nutrients on ecological status assessment and species richness patterns have not previously been assessed. Using data from 52 river sites throughout Norway, we investigated the combined effects of pH and nutrients on benthic algae assemblages, specifically 1) taxa-specific couplings between nutrient and acidity traits, 2) the degree of consistency between different biotic indices, separately for nutrients and acid conditions, 3) the impact of pH on nutrient indices and phosphorus on indices of acid conditions, and 4) the impact of pH and phosphorus supply on diatom and non-diatom taxon richness. We found that 1) acid-tolerant taxa are generally associated with nutrient-poor conditions, with only a few exceptions; this is probably more a consequence of habitat availability than reflecting true ecological niches; 2) correlation coefficients between nutrient indices and TP, as well as acid conditions indices and pH were barely affected when the confounding factor was removed; 3) the association of acid-tolerant taxa with nutrient-poor conditions means that the lowest possible nutrient index at a site, as indicated by benthic algae, is lower at acid than at circumneutral sites. Although this may be an artifact of the datasets from which taxa-specific indicator values were derived, it could lead to a drift in nutrient indices with recovery from acidification; 4) the response of non-diatom taxon richness follows a complex pattern with a synergistic interaction between nutrient supply and pH. In contrast, diatom richness follows a simple additive pattern; this suggests structural differences between diatoms and non-diatom benthic algae in their response to nutrient supply and pH; diatom taxon richness tended to increase with nutrient supply, while non-diatom richness decreased. © 2012 Elsevier B.V.

Skovsgaard J.P.,Swedish University of Agricultural Sciences | Vanclay J.K.,Southern Cross University of Australia
Forestry | Year: 2013

Indicators of forest site productivity may exhibit considerable spatial and temporal variability that should be considered in sustainable forest management. It is generally assumed that natural site conditions and, in turn, site productivity changes gradually and predictably. Our review illustrates many exceptions to this paradigm. Consequently, uni-dimensional productivity indicators such as the commonly used site index (estimated based on stand height) is not always sufficient to characterize site productivity for apparently homogeneous forest stands. To alleviate this problem, we suggest a hierarchical procedure for the estimation of forest site productivity including site mapping, unthinned reference stands (against which to measure growth performance) and adaptive modelling. The level and detail at which site mapping should be conducted (region, forest, management unit or subunit), depends on the objective (research vs. operational forestry), forest type and expected deviations in site productivity estimates compared with the cost of site mapping. Unthinned reference plots should preferably be maintained in the long term and the number of plots should increase with increasing site or stand heterogeneity (for homogeneous land we recommend one plot in 10 ha, two in 100 ha, etc.). With adaptive modelling site specific parameters can be updated at any time when new information has become available. Finally, the review indicates a need to re-define traditional measurement procedures to achieve a contemporary and rational statistical basis for the estimation of site productivity. © Institute of Chartered Foresters, 2013. All rights reserved.

Birk S.,University of Duisburg - Essen | Birk S.,Swedish University of Agricultural Sciences | van Kouwen L.,Robert Bosch GmbH | Willby N.,University of Stirling
Freshwater Biology | Year: 2012

International river catchments pose challenges for effective water resource management. Catchment-wide strategies are often complicated by differences in national bioassessment and quality classification. Intercalibration efforts aim to harmonise these differences, but rely on the consistent delineation of near-natural reference sites that are almost unavailable in today's landscape, especially for large rivers. We introduce the concept of alternative benchmarking that is based on the notion of aquatic communities at similar (low) levels of impairment associated with least-disturbed conditions (LDC) as defined by abiotic criteria. Using data acquired during the second Joint Danube Survey, we defined LDC sites based on a multivariate gradient of anthropogenic pressures, mostly related to morphological deterioration, that spans the entire navigable Danube. The river was subdivided into four stretches, each featuring homogeneous biological assemblages. Indirect gradient analysis revealed relationships between the pressure gradient and selected features of the macroinvertebrate and macrophyte community but not for diatoms or phytoplankton. We identified biological metrics suitable for the quality classification of individual stretches or the entire river. Impoundment is the major hydromorphological alteration on the Danube but various metrics still responded significantly to differences in the morphological condition of sites not affected by impoundment. A comparison of macroinvertebrate sampling techniques (airlift versus kick-and-sweep) revealed differences in how the acquired data reflect the effects of anthropogenic pressure. Biological metrics based only on kick-and-sweep sample data were insensitive to habitat deterioration in the heavily modified Upper Danube. This study exemplifies the empirical approach of alternative benchmarking in intercalibration and offers practical solutions to some of the challenges of large river bioassessment. © 2012 Blackwell Publishing Ltd.

Philippot L.,French National Institute for Agricultural Research | Philippot L.,University of Burgundy | Andert J.,Swedish University of Agricultural Sciences | Jones C.M.,Swedish University of Agricultural Sciences | And 3 more authors.
Global Change Biology | Year: 2011

Analyses of the complete genomes of sequenced denitrifying bacteria revealed that approximately 1/3 have a truncated denitrification pathway, lacking the nosZ gene encoding the nitrous oxide reductase. We investigated whether the number of denitrifiers lacking the genetic ability to synthesize the nitrous oxide reductase in soils is important for the proportion of N 2O emitted by denitrification. Serial dilutions of the denitrifying strain Agrobacterium tumefaciens C58 lacking the nosZ gene were inoculated into three different soils to modify the proportion of denitrifiers having the nitrous oxide reductase genes. The potential denitrification and N 2O emissions increased when the size of inoculated C58 population in the soils was in the same range as the indigenous nosZ community. However, in two of the three soils, the increase in potential denitrification in inoculated microcosms compared with the noninoculated microcosms was higher than the increase in N 2O emissions. This suggests that the indigenous denitrifier community was capable of acting as a sink for the N 2O produced by A. tumefaciens. The relative amount of N 2O emitted also increased in two soils with the number of inoculated C58 cells, establishing a direct causal link between the denitrifier community composition and potential N 2O emissions by manipulating the proportion of denitrifiers having the nosZ gene. However, the number of denitrifiers which do not possess a nitrous oxide reductase might not be as important for N 2O emissions in soils having a high N 2O uptake capacity compared with those with lower. In conclusion, we provide a proof of principle that the inability of some denitrifiers to synthesize the nitrous oxide reductase can influence the nature of the denitrification end products, indicating that the extent of the reduction of N 2O to N 2 by the denitrifying community can have a genetic basis. © 2010 Blackwell Publishing Ltd.

Kwantes M.,Max Planck Institute for Plant Breeding Research | Liebsch D.,Max Planck Institute for Plant Breeding Research | Liebsch D.,Justus Liebig University | Liebsch D.,Swedish University of Agricultural Sciences | Verelst W.,Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Molecular Biology and Evolution | Year: 2012

Land plants have a remarkable life cycle that alternates between a diploid sporophytic and a haploid gametophytic generation, both of which are multicellular and changed drastically during evolution. Classical MIKC MADS-domain (MIKCC) transcription factors are famous for their role in sporophytic development and are considered crucial for its evolution. About the regulation of gametophyte development, in contrast, little is known. Recent evidence indicated that the closely related MIKC* MADS-domain proteins are important for the functioning of the Arabidopsis thaliana male gametophyte (pollen). Furthermore, also in bryophytes, several MIKC* genes are expressed in the haploid generation. Therefore, that MIKC* genes have a similar role in the evolution of the gametophytic phase as MIKCC genes have in the sporophyte is a tempting hypothesis. To get a comprehensive view of the involvement of MIKC* genes in gametophyte evolution, we isolated them from a broad variety of vascular plants, including the lycophyte Selaginella moellendorffii, the fern Ceratopteris richardii, and representatives of several flowering plant lineages. Phylogenetic analysis revealed an extraordinary conservation not found in MIKCC genes. Moreover, expression and interaction studies suggest that a conserved and characteristic network operates in the gametophytes of all tested model organisms. Additionally, we found that MIKC* genes probably evolved from an ancestral MIKCC-like gene by a duplication in the Keratin-like region. We propose that this event facilitated the independent evolution of MIKC* and MIKCC protein networks and argue that whereas MIKCC genes diversified and attained new functions, MIKC* genes retained a conserved role in the gametophyte during land plant evolution. © The Author 2011.

Jactel H.,French National Institute for Agricultural Research | Birgersson G.,Swedish University of Agricultural Sciences | Andersson S.,Swedish University of Agricultural Sciences | Schlyter F.,Swedish University of Agricultural Sciences
Oecologia | Year: 2011

An increasing body of evidence indicates that the association between different plant species may lead to a reduction in insect herbivory, i. e. associational resistance. This might be due to a top-down regulation of herbivores by increased numbers of natural enemies or to a disruptive bottom-up influence of lower host plant accessibility. In particular, the richer plant communities release more diverse plant odours that may disturb olfactory-guided host choice and mating behaviour of insect herbivores, i. e. the "semiochemical diversity hypothesis". However, this hypothesis has been rarely tested experimentally in natural habitats, notably forest ecosystems. We tested the effects of non-host volatiles (NHV) on mate and host location by the pine processionary moth (PPM) at the scale of individual pine trees with branches of non-host tree (birch) at their base. Pheromone trap catches and the numbers of larval nests were both reduced by non-host presence under treated pine trees, confirming an associational resistance mediated by NHV. In both males and females, the antenna could detect several birch volatiles, including methyl salicylate (MeSa). MeSa inhibited the attraction of the PPM male to pheromone traps, as did bark and leaf chips from birch trees. Our test of three doses of MeSa at the habitat scale (50 m forest edges) showed that the reduction in the numbers of male PPM captured in traps and in larval nests was MeSa dose-dependent. These results show that odours released by deciduous non-host trees can reduce herbivory by a forest defoliator in conifers, providing support to the "semiochemical diversity hypothesis" as a mechanism of associational resistance. © 2011 Springer-Verlag.

Gessner M.O.,Eawag - Swiss Federal Institute of Aquatic Science and Technology | Gessner M.O.,ETH Zurich | Swan C.M.,University of Maryland, Baltimore | Dang C.K.,University College Cork | And 5 more authors.
Trends in Ecology and Evolution | Year: 2010

Over 100 gigatons of terrestrial plant biomass are produced globally each year. Ninety percent of this biomass escapes herbivory and enters the dead organic matter pool, thus supporting complex detritus-based food webs that determine the critical balance between carbon mineralization and sequestration. How will changes in biodiversity affect this vital component of ecosystem functioning? Based on our analysis of concepts and experiments of leaf decomposition in forest floors and streams, we suggest that changes in species diversity within and across trophic levels can significantly alter decomposition. This happens through various mechanisms that are broadly similar in forest floors and streams. Differences in diversity effects between these systems relate to divergent habitat conditions and evolutionary trajectories of aquatic and terrestrial decomposers. © 2010 Elsevier Ltd.

Van Dam R.M.,National University of Singapore | Van Dam R.M.,Harvard University | Naidoo N.,National University of Singapore | Landberg R.,Swedish University of Agricultural Sciences
Current Opinion in Lipidology | Year: 2013

PURPOSE OF REVIEW: This review summarizes the results on flavonoid intakes and the development of type 2 diabetes and cardiovascular diseases. RECENT FINDINGS: Recent advances in food composition databases have allowed the evaluation of a more comprehensive range of flavonoids in epidemiological studies. In addition, the number of randomized trials of flavonoid-rich foods has increased rapidly. Results from both cohort studies and randomized trials suggest that anthocyanidins from berries and flavan-3-ols from green tea and cocoa may lower the risk of type 2 diabetes and cardiovascular diseases. Meta-analyses of randomized trials indicate that the strongest evidence exists for a beneficial effect of green tea on LDL-cholesterol and a beneficial effect of flavan-3-ol-rich cocoa on endothelial function and insulin sensitivity. Few randomized trials had a long duration or evaluated pure flavonoid compounds. SUMMARY: Evidence from cohort studies and randomized trials suggest beneficial effects of food sources of anthocyanidins (berries) and flavan-3-ols (green tea and cocoa) on cardiovascular health. These findings need to be confirmed in long-term randomized trials, and evaluation of pure compounds will be important to establish what specific flavonoids and doses are effective. © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins.

Dekker T.,University of California at Riverside | Carde R.T.,Swedish University of Agricultural Sciences
Journal of Experimental Biology | Year: 2011

Odours are crucial cues enabling female mosquitoes to orient to prospective hosts. However, their in-flight manoeuvres to host odours are virtually unknown. Here we analyzed in 3-D the video records of female Aedes aegypti mosquitoes flying in a wind tunnel in response to host odour plumes that differed in spatial structure and composition. Following a brief (∼0.03s) encounter with CO 2, mosquitoes surged upwind and, in the absence of further encounters, counterturned without displacing upwind. These patterns resemble moth responses to encounter and loss of a filament of pheromone. Moreover, CO 2 encounters induced a highly regular pattern of counterturning across the windline in the horizontal (crosswind) and vertical planes, causing the mosquito to transect repeatedly the area where CO 2 was previously detected. However, despite the rapid changes across all three axes following an encounter with CO 2, the angular velocities remained remarkably constant. This suggests that during these CO 2- induced surges mosquitoes stabilize flight through sensors, such as the halteres and Johnston organs, sensitive to Coriolis forces. In contrast to the instantaneous responses of the mosquito CO 2, a brief encounter with a filament of human skin odour did not induce a consistent change in mosquito flight. These differential responses were reflected in further experiments with broad plumes. A broad homogeneous plume of skin odour induced rapid upwind flight and source finding, whereas a broad filamentous plume of skin odour lowered activation rates, kinetic responses and source finding compared with homogeneous plumes. Apparently, yellow fever mosquitoes need longer continuous exposure to complex skin-odour blends to induce activation and source finding. © 2011. Published by The Company of Biologists Ltd.

Lewicka M.,Karolinska Institutet | Hermanson O.,Karolinska Institutet | Rising A.U.,Swedish University of Agricultural Sciences | Rising A.U.,Spiber Technologies AB | Rising A.U.,Karolinska Institutet
Biomaterials | Year: 2012

Neural stem cells (NSCs) have the capacity to differentiate into neurons, astrocytes, and oligodendrocytes. Accordingly, NSCs hold great promise in drug screening and treatment of several common diseases. However, a major obstacle in applied stem cell research is the limitation of synthetic matrices for culturing stem cells. The objective of this study was to evaluate the suitability of recombinant spider silk (4RepCT) matrices for growth of NSCs. NSCs isolated from the cerebral cortices of mid-gestation rat embryos were cultured on either 4RepCT matrices or conventional poly-L-ornithine and fibronectin (P + F) coated polystyrene plates. From 48 h of culture, no significant differences in cell proliferation or viability were detected in NSC cultures on 4RepCT compared to control matrices (polystyrene plates coated with P + F). The NSCs retained an undifferentiated state, displaying low or no staining for markers of differentiated cells. Upon stimulation NSCs grown on 4RepCT differentiated efficiently into neuronal and astrocytic cells to virtually the same degree as control cultures, but a slightly less efficient oligodendrocyte differentiation was noted. We suggest that recombinant spider silk matrices provide a functional microenvironment and represent a useful tool for the development of new strategies in neural stem cell research. © 2012 .

Bashandy T.,CNRS Plant Genome and Development Laboratory | Guilleminot J.,CNRS Plant Genome and Development Laboratory | Vernoux T.,French National Institute for Agricultural Research | Caparros-Ruiz D.,Autonomous University of Barcelona | And 3 more authors.
Plant Cell | Year: 2010

Intracellular redox status is a critical parameter determining plant development in response to biotic and abiotic stress. Thioredoxin (TRX) and glutathione are key regulators of redox homeostasis, and the TRX and glutathione pathways are essential for postembryonic meristematic activities. Here, we show by associating TRX reductases (ntra ntrb) and glutathione biosynthesis (cad2) mutations that these two thiol reduction pathways interfere with developmental processes through modulation of auxin signaling. The triple ntra ntrb cad2 mutant develops normally at the rosette stage, undergoes the floral transition, but produces almost naked stems, reminiscent of the phenotype of several mutants affected in auxin transport or biosynthesis. In addition, the ntra ntrb cad2 mutant shows a loss of apical dominance, vasculature defects, and reduced secondary root production, several phenotypes tightly regulated by auxin. We further show that auxin transport capacities and auxin levels are perturbed in the mutant, suggesting that the NTR-glutathione pathways alter both auxin transport and metabolism. Analysis of ntr and glutathione biosynthesis mutants suggests that glutathione homeostasis plays a major role in auxin transport as both NTR and glutathione pathways are involved in auxin homeostasis. © 2010 American Society of Plant Biologists.

Dalin P.,Swedish University of Agricultural Sciences | Dudley T.L.,University of California at Santa Barbara
Evolutionary Applications | Year: 2012

classical weed biological control, small collections of arthropods are made from one or a few sites the native range of the target plant and are introduced to suppress the plant where it has become invasive, often across a wide geographic range. Ecological mismatches the new range are likely, and success using the biocontrol agent may depend on postrelease evolution of beneficial life history traits. this study, we measure the evolution of critical day length for diapause induction (day length at which 50% of the population enters dormancy), a beetle (Diorhabda carinulata) introduced into North America from China to control an exotic shrub, Tamarix spp. Beetle populations were sampled from four sites North America 7years after introduction, and critical day length was shown to have declined, forming a cline over a latitudinal gradient At one field site, decreased critical day length was correlated with 16 additional days of reproductive activity, resulting a closer match between beetle life history and the phenology of Tamarix. These findings indicate an enhanced efficacy and an increasingly wider range for D. carinulata Tamarix control. © 2012 Blackwell Publishing Ltd.

Manley M.,Stellenbosch University | du Toit G.,Stellenbosch University | Geladi P.,Swedish University of Agricultural Sciences
Analytica Chimica Acta | Year: 2011

The combination of near infrared (NIR) hyperspectral imaging and chemometrics was used to follow the diffusion of conditioning water over time in wheat kernels of different hardnesses. Conditioning was attempted with deionised water (dH2O) and deuterium oxide (D2O). The images were recorded at different conditioning times (0-36h) from 1000 to 2498nm with a line scan imaging system. After multivariate cleaning and spectral pre-processing (either multiplicative scatter correction or standard normal variate and Savitzky-Golay smoothing) six principal components (PCs) were calculated. These were studied visually interactively as score images and score plots. As no clear clusters were present in the score plots, changes in the score plots were investigated by means of classification gradients made within the respective PCs. Classes were selected in the direction of a PC (from positive to negative or negative to positive score values) in almost equal segments. Subsequently loading line plots were used to provide a spectroscopic explanation of the classification gradients. It was shown that the first PC explained kernel curvature. PC3 was shown to be related to a moisture-starch contrast and could explain the progress of water uptake. The positive influence of protein was also observed. The behaviour of soft, hard and very hard kernels was different in this respect, with the uptake of water observed much earlier in the soft kernels than in the harder ones. The harder kernels also showed a stronger influence of protein in the loading line plots. Difference spectra showed interpretable changes over time for water but not for D2O which had a too low signal in the wavelength range used. NIR hyperspectral imaging together with exploratory chemometrics, as detailed in this paper, may have wider applications than merely conditioning studies. © 2010 Elsevier B.V.

News Article | November 24, 2015
Site: phys.org

The new kind of rice grows in a manner that nearly eliminates the production of methane, a potent greenhouse gas. And rice is a big source of methane: Scientists estimate that somewhere in the neighborhood of 8 to 15 percent of global methane emissions come from rice paddies around the world. Methane is 20 times more efficient at trapping heat in atmosphere than its better-known counterpart, carbon dioxide, making the team's contribution especially important for climate issues. The research has been recognized with a "Best of What's New" award for 2015 by Popular Science. The work was named the grand prize winner in the magazine's engineering category, one of 10 categories in which a total of 100 research developments around the globe were recognized. The awards are described in the December issue of the magazine. PNNL scientist Christer Jansson led the team; he is director of plant sciences at EMSL, the Environmental Molecular Sciences Laboratory, a DOE user facility at PNNL. For more than a decade he has worked closely with Chuanxin Sun of the Swedish University of Agricultural Sciences, who has contributed significantly to the research on rice. The two published a research paper about the rice in July in Nature, together with other researchers at the Swedish institution and colleagues at China's Fujian Academy of Agricultural Sciences and Hunan Agricultural University. To create the rice, the team identified a gene in barley that directs how that plant uses carbon, then spliced that gene into common rice. The change redirected the way the rice plant uses the carbon it pulls from the atmosphere, causing the plant to send more carbon into the plant's grain and stems and less into its roots. That change increases the amount of starch and the yield of rice and reduces the carbon available to the roots, where bacteria convert much of the substance into methane. "This is a win-win finding," said Jansson, a plant biochemist. "The process results in reduced methane emissions, which helps to mitigate climate change, and also results in more biomass - more food. This dual effect is very positive." Much of Jansson's work focuses on understanding how plants absorb light and tap water and carbon to carry out photosynthesis. The work is central to scientists who investigate "bioenergy," which involves creating or tapping biological materials for energy. Jansson has worked with crops like sorghum, rice and tobacco to discover new ways to create plants that offer novel energy traits. Explore further: A cyclical effect: More atmospheric CO2, more greenhouse gas per grain of rice

News Article | April 21, 2016
Site: phys.org

The medium ground finch (Geospiza fortis) diverged in beak size from the large ground finch (Geospiza magnirostris) on Daphne Major Island, Galápagos following a severe drought. Credit: © Peter R. Grant The most characteristic feature of Darwin's finches is the diversification of beak morphology that has allowed these species to expand their utilization of food resources in the Galápagos archipelago. A team of scientists from Uppsala University and Princeton University has now identified a gene that explains variation in beak size within and among species. The gene contributed to a rapid shift in beak size of the medium ground finch following a severe drought. The study is published in Science. Darwin's finches are a classical example of an adaptive radiation. Their common ancestor arrived on the Galápagos about two million years ago. During the time that has passed the Darwin's finches have evolved into 18 recognized species differing in body size, beak shape, song and feeding behaviour. Changes in the size and form of the beak have enabled different species to utilize different food resources such us insects, seeds, nectar from cactus flowers as well as blood from seabirds, all driven by Darwinian selection. In a previous study from the same team the ALX1 gene was revealed to control beak shape (pointed or blunt) and now a gene (HMGA2) affecting beak size has been identified. 'Our data show that beak morphology is affected by many genes as is the case for most biological traits. However, we are convinced that we now have identified the two loci with the largest individual effects that have shaped the evolution of beak morphology among the Darwin's finches', says Sangeet Lamichhaney PhD student at Uppsala University and first author of the study. Charles Darwin was the first to describe the principle of character divergence (now known as ecological character displacement), which means that species that compete for the same food resources tend to diverge from each other and thereby reduce competition. This evolutionary process has been invoked as an important mechanism in the assembly of complex ecological communities. One of the few clear examples of ecological character displacement was previously documented in Darwin's finches by Peter and Rosemary Grant at Princeton University, coauthors on this new study. The medium ground finch diverged in beak size from the large ground finch on Daphne Major Island, following a severe drought in 2004-2005. 'We previously documented that the average beak size of the medium ground finch population became smaller during this drought due to a high mortality among individuals with large beaks because they could not compete well with the large ground finch,' say Peter and Rosemary Grant, who carried out field work on the Galápagos during a 40 year period. 'Now we have demonstrated that the HMGA2 locus played a critical role in this evolutionary shift and that natural selection acting on this gene during the drought is one of the highest yet recorded in nature,' continues Peter and Rosemary Grant. HMGA2 has previously been associated with variation in body size in dogs and horses and it is one of the genes that show the most consistent association with variation in stature in humans, a trait that is affected by hundreds of genes. HMGA2 has also a role in cancer biology since it affects the epithelial-mesenchymal transition (EMT) that is important for metastasis and cancer progression. 'The HMGA2 gene regulates the expression of other genes but the exact mechanism how it controls beak size in Darwin's finches or human stature is unknown,' says Leif Andersson, Uppsala University, Swedish University of Agricultural Sciences and Texas A&M University, who led the study. 'It is very fascinating that this gene pops up in many different species as a gene affecting growth and in humans also as a gene affecting dysregulated cell growth in cancer. It is clear that more research to better understand the function of this gene is well justified,' ends Leif Andersson. Explore further: New Research on Darwin's Finches Offers Rare Glimpse Into How Species Diverge More information: "A beak size locus in Darwin's finches facilitated character displacement during a drought," Science, DOI: 10.1126/science.aad8786

Derkacheva M.,Swedish University of Agricultural Sciences | Derkacheva M.,ETH Zurich | Hennig L.,Swedish University of Agricultural Sciences | Hennig L.,ETH Zurich | Hennig L.,Science for Life Laboratory
Journal of Experimental Botany | Year: 2014

Polycomb group (PcG) proteins evolved early in evolution, probably in the common ancestor of animals and plants. In some unicellular organisms, such as Chlamydomonas and Tetrahymena, PcG proteins silence genes in heterochromatin, suggesting an ancestral function in genome defence. In angiosperms, the PcG system controls many developmental transitions. A PcG function in the vernalization response evolved especially in Brassicaceaea. Thus, the role of PcG proteins has changed during evolution to match novel needs. Recent studies identified many proteins associated with plant PcG protein complexes. Possible functions of these interactions are discussed here. We highlight recent findings about recruitment of PcG proteins in plants in comparison with animal system. Through the new data, a picture emerges in which PcG protein complexes do not function in sequential linear pathways but as dynamically interacting networks allowing stabilizing feedback loops. We discuss how the interplay between different PcG protein complexes can enable establishment, maintenance, and epigenetic inheritance of H3K27me3. © The Author 2013.

Lofgren S.,Swedish University of Agricultural Sciences | Gustafsson J.P.,KTH Royal Institute of Technology | Bringmark L.,Swedish University of Agricultural Sciences
Science of the Total Environment | Year: 2010

Numerous studies report increased concentrations of dissolved organic carbon (DOC) during the last two decades in boreal lakes and streams in Europe and North America. Recently, a hypothesis was presented on how various spatial and temporal factors affect the DOC dynamics. It was concluded that declining sulphur deposition and thereby increased DOC solubility, is the most important driver for the long-term DOC concentration trends in surface waters. If this recovery hypothesis is correct, the DOC levels should increase both in the soil solution as well as in the surrounding surface waters as soil pH rises and the ionic strength declines due to the reduced input of SO4 2- ions. In this project a geochemical model was set up to calculate the net humic charge and DOC solubility trends in soils during the period 1996-2007 at two integrated monitoring sites in southern Sweden, showing clear signs of acidification recovery. The Stockholm Humic Model was used to investigate whether the observed DOC solubility is related to the humic charge and to examine how pH and ionic strength influence it. Soil water data from recharge and discharge areas, covering both podzols and riparian soils, were used. The model exercise showed that the increased net charge following the pH increase was in many cases counteracted by a decreased ionic strength, which acted to decrease the net charge and hence the DOC solubility. Thus, the recovery from acidification does not necessarily have to generate increasing DOC trends in soil solution. Depending on changes in pH, ionic strength and soil Al pools, the trends might be positive, negative or indifferent. Due to the high hydraulic connectivity with the streams, the explanations to the DOC trends in surface waters should be searched for in discharge areas and peat lands. © 2010 Elsevier B.V.

Tiberg C.,Swedish University of Agricultural Sciences | Sjostedt C.,KTH Royal Institute of Technology | Persson I.,Swedish University of Agricultural Sciences | Gustafsson J.P.,KTH Royal Institute of Technology
Geochimica et Cosmochimica Acta | Year: 2013

Transport of lead(II) and copper(II) ions in soil is affected by the soil phosphorus status. Part of the explanation may be that phosphate increases the adsorption of copper(II) and lead(II) to iron (hydr)oxides in soil, but the details of these interactions are poorly known. Knowledge about such mechanisms is important, for example, in risk assessments of contaminated sites and development of remediation methods. We used a combination of batch experiments, extended X-ray absorption fine structure (EXAFS) spectroscopy and surface complexation modeling with the three-plane CD-MUSIC model to study the effect of phosphate on sorption of copper(II) and lead(II) to ferrihydrite. The aim was to identify the surface complexes formed and to derive constants for the surface complexation reactions. In the batch experiments phosphate greatly enhanced the adsorption of copper(II) and lead(II) to ferrihydrite at pH. <. 6. The largest effects were seen for lead(II).Based on interpretation of the EXAFS spectra edge-sharing bidentate copper(II) or lead(II) complexes predominated in the single-sorbate systems with ferrihydrite. Lead(II) EXAFS spectra suggested a distinct change of coordination in the presence of phosphate, i.e. the signal from edge-sharing complexes diminished and a longer Pb···Fe distance appeared at about 4. Å. A similar, but less pronounced, pattern was observed for copper(II). Based on the results from interpretation of EXAFS spectra and surface complexation modeling with the CD-MUSIC model the enhanced sorption in presence of phosphate was most satisfactorily explained by the appearance of ternary metal-phosphate complexes in which the metal interacts directly with the surface.In conclusion, geochemical models used for simulating trace element behavior in acidic environments seem to require ternary metal-phosphate surface complexes to properly describe partitioning of metals between solution and the solid phase. © 2013 Elsevier Ltd.

Arthurson V.,Swedish University of Agricultural Sciences | Sessitsch A.,AIT Austrian Institute of Technology | Jaderlund L.,Swedish University of Agricultural Sciences
FEMS Microbiology Letters | Year: 2011

Several outbreaks caused by pathogenic bacteria are related to the consumption of raw produce contaminated by animal manure. The majority of these outbreaks have been linked to Salmonella spp. We examined the ability of Salmonella enterica serovar Weltevreden to persist and survive in manure and soil as well as disseminate to, and persist on, spinach roots and leaves. Significantly higher numbers of S. Weltevreden inoculated into manure and applied to soil before planting spinach were found in soil than in pot cultures, where the pathogen had been inoculated directly into soil 14 days postplanting. Moreover, the pathogen seemed to disperse from manure to spinach roots, as we observed a continuous increase in the number of contaminated replicate pot cultures throughout the evaluation period. We also found that, in some cases, S. Weltevreden present in the phyllosphere had the ability to persist for the entire evaluation period (21 days), with only slight reductions in cell numbers. The results from the present study show that S. Weltevreden is capable of persisting in soil, roots and shoots for prolonged periods, indicating the importance of strict monitoring of untreated animal manure before considering its application to agricultural land. © 2010 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Kardol P.,Swedish University of Agricultural Sciences | De Deyn G.B.,Wageningen University | Laliberte E.,University of Western Australia | Mariotte P.,Swiss Federal Institute of forest | Hawkes C.V.,University of Texas at Austin
Journal of Ecology | Year: 2013

Plant effects on soil biota can result in feedbacks affecting plant performance, with consequences for plant community and ecosystem dynamics on short and long time-scales. In addition, the strength and direction of plant-soil feedbacks depend on temporal shifts in abiotic environmental conditions. We synthesize current knowledge on temporal aspects of plant-soil feedbacks and present new ideas to better understand and predict the effects of plant-soil feedbacks on community and ecosystem properties across temporal scales. Explaining short-term temporal feedback dynamics requires us to better understand mechanistic linkages between plants, soil organisms and locally available resources. On the other hand, we need to refine our understanding of the context-dependency of plant-soil feedbacks, as the strength and direction of feedback interactions are influenced by 'external' temporal ecosystem dynamics, such as variation in soil resource availability after disturbance or during succession. Synthesis. Based on our synthesis of temporal aspects of plant-soil feedbacks, we suggest three main avenues for future research: (i) how plant-soil feedbacks changes with ontogeny, (ii) how plant and soil organism traits drive temporal variation in plant-soil feedbacks and (iii) how environmental changes across temporal scales alter the strength and direction of plant-soil feedbacks. © 2013 The Authors. Journal of Ecology © 2013 British Ecological Society.

Lindbladh M.,Swedish University of Agricultural Sciences | Fraver S.,University of Maine, United States | Edvardsson J.,University of Bern | Felton A.,Swedish University of Agricultural Sciences
Biological Conservation | Year: 2013

The importance of long-term historical information derived from paleoecological studies has long been recognized as a fundamental aspect of effective conservation. However, there remains some uncertainty regarding the extent to which paleoecology can inform on specific issues of high conservation priority, at the scale for which conservation policy decisions often take place. Here we review to what extent the past occurrence of three fundamental aspects of forest conservation can be assessed using paleoecological data, with a focus on northern Europe. These aspects are (1) tree species composition, (2) old/large trees and coarse woody debris, and (3) natural disturbances. We begin by evaluating the types of relevant historical information available from contemporary forests, then evaluate common paleoecological techniques, namely dendrochronology, pollen, macrofossil, charcoal, and fossil insect and wood analyses. We conclude that whereas contemporary forests can be used to estimate historical, natural occurrences of several of the aspects addressed here (e.g. old/large trees), paleoecological techniques are capable of providing much greater temporal depth, as well as robust quantitative data for tree species composition and fire disturbance, qualitative insights regarding old/large trees and woody debris, but limited indications of past windstorms and insect outbreaks. We also find that studies of fossil wood and paleoentomology are perhaps the most underutilized sources of information. Not only can paleoentomology provide species specific information, but it also enables the reconstruction of former environmental conditions otherwise unavailable. Despite the potential, the majority of conservation-relevant paleoecological studies primarily focus on describing historical forest conditions in broad terms and for large spatial scales, addressing former climate, land-use, and landscape developments, often in the absence of a specific conservation context. In contrast, relatively few studies address the most pressing conservation issues in northern Europe, often requiring data on the presence or quantities of dead wood, large trees or specific tree species, at the scale of the stand or reserve. Furthermore, even fewer examples exist of detailed paleoecological data being used for conservation planning, or the setting of operative restorative baseline conditions at local scales. If ecologist and conservation biologists are going to benefit to the full extent possible from the ever-advancing techniques developed by the paleoecological sciences, further integration of these disciplines is desirable. © 2013 Elsevier Ltd.

Powell J.R.,University of Western Sydney | Welsh A.,University of Illinois at Urbana - Champaign | Hallin S.,Swedish University of Agricultural Sciences
Ecology | Year: 2015

Microorganisms drive biogeochemical processes, but linking these processes to real changes in microbial communities under field conditions is not trivial. Here, we present a model-based approach to estimate independent contributions of microbial community shifts to ecosystem properties. The approach was tested empirically, using denitrification potential as our model process, in a spatial survey of arable land encompassing a range of edaphic conditions and two agricultural production systems. Soil nitrate was the most important single predictor of denitrification potential (the change in Akaike's information criterion, corrected for sample size, ΔAICc= 20.29); however, the inclusion of biotic variables (particularly the evenness and size of denitrifier communities [ΔAICc=12.02], and the abundance of one denitrifier genotype [ΔAICc= 18.04]) had a substantial effect on model precision, comparable to the inclusion of abiotic variables (biotic R2=0.28, abiotic R2=0.50, biotic +abiotic R2=0.76). This approach provides a valuable tool for explicitly linking microbial communities to ecosystem functioning. By making this link, we have demonstrated that including aspects of microbial community structure and diversity in biogeochemical models can improve predictions of nutrient cycling in ecosystems and enhance our understanding of ecosystem functionality. © 2015 by the Ecological Society of America.

van Schaik J.W.J.,Swedish University of Agricultural Sciences | Kleja D.B.,Swedish University of Agricultural Sciences | Gustafsson J.P.,KTH Royal Institute of Technology
Geochimica et Cosmochimica Acta | Year: 2010

Vast amounts of knowledge about the proton- and metal-binding properties of dissolved organic matter (DOM) in natural waters have been obtained in studies on isolated humic and fulvic (hydrophobic) acids. Although macromolecular hydrophilic acids normally make up about one-third of DOM, their proton- and metal-binding properties are poorly known. Here, we investigated the acid-base and Cu-binding properties of the hydrophobic (fulvic) acid fraction and two hydrophilic fractions isolated from a soil solution. Proton titrations revealed a higher total charge for the hydrophilic acid fractions than for the hydrophobic acid fraction. The most hydrophilic fraction appeared to be dominated by weak acid sites, as evidenced by increased slope of the curve of surface charge versus pH at pH values above 6. The titration curves were poorly predicted by both Stockholm Humic Model (SHM) and NICA-Donnan model calculations using generic parameter values, but could be modelled accurately after optimisation of the proton-binding parameters (pH ≤ 9). Cu-binding isotherms for the three fractions were determined at pH values of 4, 6 and 9. With the optimised proton-binding parameters, the SHM model predictions for Cu binding improved, whereas the NICA-Donnan predictions deteriorated. After optimisation of Cu-binding parameters, both models described the experimental data satisfactorily. Iron(III) and aluminium competed strongly with Cu for binding sites at both pH 4 and pH 6. The SHM model predicted this competition reasonably well, but the NICA-Donnan model underestimated the effects significantly at pH 6. Overall, the Cu-binding behaviour of the two hydrophilic acid fractions was very similar to that of the hydrophobic acid fraction, despite the differences observed in proton-binding characteristics. These results show that for modelling purposes, it is essential to include the hydrophilic acid fraction in the pool of 'active' humic substances. © 2009 Elsevier Ltd. All rights reserved.

Sjostedt C.S.,KTH Royal Institute of Technology | Gustafsson J.P.,KTH Royal Institute of Technology | Kohler S.J.,Swedish University of Agricultural Sciences
Environmental Science and Technology | Year: 2010

A consistent chemical equilibrium model that calculates pH from charge balance constraints and aluminum and iron speciation in the presence of natural organic matter is presented. The model requires input data for total aluminum, iron, organic carbon, fluoride, sulfate, and charge balance ANC. The model is calibrated to pH measurements (n = 322) by adjusting the fraction of active organic matter only, which results in an error of pH prediction on average below 0.2 pH units. The small systematic discrepancy between the analytical results for the monomeric aluminum fractionation and the model results is corrected for separately for two different fractionation techniques (n = 499) and validated on a large number (n = 3419) of geographically widely spread samples all over Sweden. The resulting average error for inorganic monomeric aluminum is around 1 μM. In its present form the model is the first internally consistent modeling approach for Sweden and may now be used as a tool for environmental quality management. Soil gibbsite with a log*K s of 8.29 at 25 °C together with a pH dependent loading function that uses molar Al/C ratios describes the amount of aluminum in solution in the presence of organic matter if the pH is roughly above 6.0. © 2010 American Chemical Society.

Sauer M.,CSIC - National Center for Biotechnology | Robert S.,Swedish University of Agricultural Sciences | Kleine-Vehn J.,University of Natural Resources and Life Sciences, Vienna
Journal of Experimental Botany | Year: 2013

Auxin is a plant hormone involved in an extraordinarily broad variety of biological mechanisms. These range from basic cellular processes, such as endocytosis, cell polarity, and cell cycle control over localized responses such as cell elongation and differential growth, to macroscopic phenomena such as embryogenesis, tissue patterning, and de novo formation of organs. Even though the history of auxin research reaches back more than a hundred years, we are still far from a comprehensive understanding of how auxin governs such a wide range of responses. Some answers to this question may lie in the auxin molecule itself. Naturally occurring auxin-like substances have been found and they may play roles in specific developmental and cellular processes. The molecular mode of auxin action can be further explored by the utilization of synthetic auxin-like molecules. A second area is the perception of auxin, where we know of three seemingly independent receptors and signalling systems, some better understood than others, but each of them probably involved in distinct physiological processes. Lastly, auxin is actively modified, metabolized, and intracellularly compartmentalized, which can have a great impact on its availability and activity. In this review, we will give an overview of these rather recent and emerging areas of auxin research and try to formulate some of the open questions. Without doubt, the manifold facets of auxin biology will not cease to amaze us for a long time to come. © The Author [2013]. Published by Oxford University Press [on behalf of the Society for Experimental Biology]. All rights reserved.

Liu J.,Durham University | Mehdi S.,Durham University | Topping J.,Durham University | Tarkowski P.,Swedish University of Agricultural Sciences | Lindsey K.,Durham University
Molecular Systems Biology | Year: 2010

An important question in plant biology is how genes influence the crosstalk between hormones to regulate growth. In this study, we model POLARIS (PLS) gene function and crosstalk between auxin, ethylene and cytokinin in Arabidopsis. Experimental evidence suggests that PLS acts on or close to the ethylene receptor ETR1, and a mathematical model describing possible PLS-ethylene pathway interactions is developed, and used to make quantitative predictions about PLS-hormone interactions. Modelling correctly predicts experimental results for the effect of the pls gene mutation on endogenous cytokinin concentration. Modelling also reveals a role for PLS in auxin biosynthesis in addition to a role in auxin transport. The model reproduces available mutants, and with new experimental data provides new insights into how PLS regulates auxin concentration, by controlling the relative contribution of auxin transport and biosynthesis and by integrating auxin, ethylene and cytokinin signalling. Modelling further reveals that a bell-shaped dose-response relationship between endogenous auxin and root length is established via PLS. This combined modelling and experimental analysis provides new insights into the integration of hormonal signals in plants. © 2010 EMBO and Macmillan Publishers Limited. All rights reserved.

Westerholm M.,Swedish University of Agricultural Sciences | Hansson M.,Swedish Institute of Agricultural and Environmental Engineering | Schnurer A.,Swedish University of Agricultural Sciences
Bioresource Technology | Year: 2012

Whole stillage, as sole substrate or co-digested with cattle manure, was evaluated as substrate for biogas production in five mesophilic laboratory-scale biogas reactors, operating semi-continuously for 640days. The process performance was monitored by chemical parameters and by quantitative analysis of the methanogenic and acetogenic population. With whole stillage as sole substrate the process showed clear signs of instability after 120days of operation. However, co-digestion with manure clearly improved biogas productivity and process stability and indicated increased methane yield compared with theoretical values. The methane yield at an organic loading rate (OLR) at 2.8gVS/(L×day) and a hydraulic retention time (HRT) of 45days with a substrate mixture 85% whole stillage and 15% manure (based on volatile solids [VS]) was 0.31N L CH 4/gVS. Surprisingly, the abundance of the methanogenic and acetogenic populations remained relatively stable throughout the whole operation and was not influenced by process performance. © 2012 Elsevier Ltd.

Eigenbrot C.,Genentech | Ultsch M.,Genentech | Dubnovitsky A.,Swedish University of Agricultural Sciences | Abrahmsen L.,Affibody | Hard T.,Swedish University of Agricultural Sciences
Proceedings of the National Academy of Sciences of the United States of America | Year: 2010

The human epidermal growth factor receptor 2 (HER2) is specifically overexpressed in tumors of several cancers, including an aggressive form of breast cancer. It is therefore a target for both cancer diagnostics and therapy. The 58 amino acid residue ZHER2 affibody molecule was previously engineered as a high-affinity binder of HER2. Here we determined the structure of ZHER2 in solution and the crystal structure of ZHER2 in complex with the HER2 extracellular domain. ZHER2 binds to a conformational epitope on HER2 that is distant from those recognized by the therapeutic antibodies trastuzumab and pertuzumab. Its small size and lack of interference may provide ZHER2 with advantages for diagnostic use or even for delivery of therapeutic agents to HER2-expressing tumors when trastuzumab or pertuzumab are already employed. Biophysical characterization shows that ZHER2 is thermodynamically stable in the folded state yet undergoing conformational interconversion on a submillisecond time scale. The data suggest that it is the HER2-binding conformation that is formed transiently prior to binding. Still, binding is very strong with a dissociation constant KD = 22 pM, and perfect conformational homogeneity is therefore not necessarily required in engineered binding proteins. A comparison of the original Z domain scaffold to free and bound ZHER2 structures reveals how high-affinity binding has evolved during selection and affinity maturation and suggests how a compromise between binding surface optimization and stability and dynamics of the unbound state has been reached.

Ranius T.,Swedish University of Agricultural Sciences | Johansson V.,Swedish University of Agricultural Sciences | Fahrig L.,Carleton University
Ecography | Year: 2010

This study aimed at comparing six patch connectivity measures by fitting them to field data. We used occupancy data for eight beetle and two pseudoscorpion species from 281 hollow oaks in southeast Sweden. Species occupancy was modelled in relation to tree characteristics and one measure of patch connectivity at a time. For each connectivity measure we searched for the spatial scale that generated the best fit to field data. Connectivity measures that only include occupied patches provided better model fits than those that include all patches. When occupancy data are absent for surrounding habitat patches, information that reflects occurrence probabilities can be included in the connectivity measure. However, in this study incorporation of such information resulted in only a slight improvement of model fit. A frequently used connectivity measure based on the negative exponential function was relatively poor in explaining species' occurrence; for eight species out of nine a buffer measure was better. A better fit was obtained when the negative exponential function was modified to take into account that habitat patches may "compete" for the immigrants. The spatial scale with the best fit tended to be larger when we used connectivity measures in which dispersal sources are identified with lower precision. Thus, the outcomes from different multiple-scale studies are not directly comparable if the density of dispersal sources is not measured in the same way. Overall we conclude that buffer measures are useful, as they give good predictions and are easy to understand and use. If a biologically more realistic measure is needed, one that up-weights the closest patches should be used. Finally, the possibility that habitat patches may compete with each other for immigrants should be considered when selecting a connectivity measure. © 2010 The Authors.

Katsenis A.D.,National and Kapodistrian University of Athens | Kessler V.G.,Swedish University of Agricultural Sciences | Papaefstathiou G.S.,National and Kapodistrian University of Athens
Dalton Transactions | Year: 2011

The exploration of the NiX2/py2CO/Et3N (X = F, Cl, Br, I; py2CO = di-2-pyridyl ketone; Et3N = triethylamine) reaction system led to the tetranuclear [Ni4Cl 2{py2C(OH)O}2{py2C(OMe)O} 2(MeOH)2]Cl2·2Et2O (1·2Et2O) and [Ni4Br2{py 2C(OH)O}2{py2C(OMe)O}2(MeOH) 2]Br2·2Et2O (2·2Et2O) and the trinuclear [Ni3{py2C(OMe)O}4]I 2·2.5MeOH (3·2.6MeOH), [Ni3{py 2C(OMe)O}4](NO3)0.65I 1.35·2MeOH (4·2MeOH) and [Ni3{py 2C(OMe)O}4](SiF6)0.8F 0.4·3.5MeOH (5·3.5MeOH) aggregates. The presence of the intermediate size Cl- and Br- anions resulted in planar tetranuclear complexes with a dense hexagonal packing of cations and donor atoms (tetramolybdate topology) where the X- anions participate in the core acting as bridging ligands. The F- and I- anions do not favour the above arrangement resulting in triangular complexes with an isosceles topology. The magnetic properties of 1-3 have been studied by variable-temperature dc, variable-temperature and variable-field ac magnetic susceptibility techniques and magnetization measurements. All complexes are high-spin with ground states S = 4 for 1 and 2 and S = 3 for 3. © 2011 The Royal Society of Chemistry.

Gentry M.,Swedish University of Agricultural Sciences | Hennig L.,Swedish University of Agricultural Sciences | Hennig L.,Science for Life Laboratory
Experimental Cell Research | Year: 2014

Establishment and dynamic regulation of a higher order chromatin structure is an essential component of development. Chromatin remodelling complexes such as the SWI2/SNF2 family of ATP-dependent chromatin remodellers can alter chromatin architecture by changing nucleosome positioning or substituting histones with histone variants. These remodellers often act in concert with chromatin modifiers such as the polycomb group proteins which confer repressive states through modification of histone tails. These mechanisms are highly conserved across the eukaryotic kingdom although in plants, owing to the maintenance of dedifferentiated cell states that allow for post-embyronic changes in development, strict control of chromatin remodelling is even more paramount. Recent and ongoing studies in the model plant Arabidopsis thaliana have found that while the major families of the SWI2/SNF2 ATPase chromatin remodellers are represented, a number of redundancies and divergent functions have emerged that show a break from the roles of their metazoan counterparts. This review focusses on the SNF2 and CHD families of ATP-dependent remodellers and their roles in plant development. © 2013 Elsevier Inc.

Nybom H.,Swedish University of Agricultural Sciences | Weising K.,University of Kassel | Rotter B.,GenXPro GmbH
Investigative Genetics | Year: 2014

Almost three decades ago Alec Jeffreys published his seminal Nature papers on the use of minisatellite probes for DNA fingerprinting of humans (Jeffreys and colleagues Nature 1985, 314:67-73 and Nature 1985, 316:76-79). The new technology was soon adopted for many other organisms including plants, and when Hilde Nybom, Kurt Weising and Alec Jeffreys first met at the very First International Conference on DNA Fingerprinting in Berne, Switzerland, in 1990, everybody was enthusiastic about the novel method that allowed us for the first time to discriminate between humans, animals, plants and fungi on the individual level using DNA markers. A newsletter coined " Fingerprint News" was launched, T-shirts were sold, and the proceedings of the Berne conference filled a first book on " DNA fingerprinting: approaches and applications" Four more conferences were about to follow, one on each continent, and Alec Jeffreys of course was invited to all of them. Since these early days, methodologies have undergone a rapid evolution and diversification. A multitude of techniques have been developed, optimized, and eventually abandoned when novel and more efficient and/or more reliable methods appeared. Despite some overlap between the lifetimes of the different technologies, three phases can be defined that coincide with major technological advances. Whereas the first phase of DNA fingerprinting (" the past" ) was dominated by restriction fragment analysis in conjunction with Southern blot hybridization, the advent of the PCR in the late 1980s gave way to the development of PCR-based single- or multi-locus profiling techniques in the second phase. Given that many routine applications of plant DNA fingerprinting still rely on PCR-based markers, we here refer to these methods as " DNA fingerprinting in the present" , and include numerous examples in the present review. The beginning of the third phase actually dates back to 2005, when several novel, highly parallel DNA sequencing strategies were developed that increased the throughput over current Sanger sequencing technology 1000-fold and more. High-speed DNA sequencing was soon also exploited for DNA fingerprinting in plants, either in terms of facilitated marker development, or directly in the sense of " genotyping-by-sequencing" Whereas these novel approaches are applied at an ever increasing rate also in non-model species, they are still far from routine, and we therefore treat them here as " DNA fingerprinting in the future" © 2014 Nybom et al.; licensee BioMed Central Ltd.

Bozhkov P.V.,Swedish University of Agricultural Sciences | Smertenko A.P.,Durham University | Zhivotovsky B.,Karolinska Institutet
Science Signaling | Year: 2010

Execution of programmed cell death (PCD) in nonmetazoan organisms is morphologically different from apoptotic PCD in animals and lacks a number of key molecular components of apoptotic machinery, including caspases. Yet protozoan, fungal, and plant cells exhibit caspase-like proteolytic activities, which increase in a PCD-dependent manner. This poses a question whether nonmetazoan organisms contain structurally dissimilar proteases that functionally substitute for caspases. Putative ancestors of caspases, metacaspases, are candidates for this role; however, their distinct substrate specificity raises doubts. The identification of a common biological target of caspases and metacaspases and previously unknown functions unrelated to cell death of metacaspases provide new food for thought.

Sjoman J.D.,Swedish University of Agricultural Sciences | Gill S.E.,Mersey Forest Team
Urban Forestry and Urban Greening | Year: 2014

Depending on the spatial density of built cover and location within a catchment, residential areas make varying contributions to surface runoff throughout different rainfall events. This study examined these contributions and the associated effect of different surface covers and sustainable drainage systems on runoff generation. The Soil Conservation Service curve number (SCS-CN) method was applied to analyse urban development in the Höjeå river catchment in southern Sweden. The results indicated that identical amounts of surface runoff are generated by low-density residential areas on heavy clay soils and high-density residential areas on sandy soils. However, increasing the density of built-up areas on sandy soils is likely to be more disruptive to the hydrological balance and to generate a greatly increasing difference in runoff as building density and impermeable surface area increase. A similar pattern is likely to occur if rainfall intensity increases. It may therefore be appropriate to apply different planning considerations to residential developments depending on the existing soil group, e.g. conserving existing vegetated surfaces on sandy soil and incorporating permeable paving materials and sub-surface infiltration beds in development on clayey soils. Increased area of impermeable surface cover will increase surface runoff in all residential areas, irrespective of building density, soil group and rainfall intensity. However, adapting a systems approach in combining vegetative structures and permeable paving materials with subsurface infiltration beds can help mitigate the impact of surface runoff, particularly in urban developments on clay-rich soils. © 2013 Elsevier GmbH.

News Article | February 15, 2017
Site: www.eurekalert.org

Researchers from University of Gothenburg and the Swedish University of Agricultural Sciences (SLU) show that both species diversity and habitat diversity are critical to understand the functioning of ecosystems. Marine shallow-water environments, where this research was performed, are highly productive systems organized into distinct habitats. There are sandy beaches and silty mud, areas covered by cyanobacterial mats and meadows of plants. They represent very different habitats for microorganisms, such as bacteria and microalgae. These microorganisms perform various functions. For example, they produce oxygen, reduce eutrophication by the retention of bioavailable nutrients, and their habitats serve as nurseries for fish. Christian Alsterberg and co-workers investigated the relative importance of habitat diversity and microbial diversity for how coastal sediments function. Although the significance of these environments has been acknowledged before, the importance of the diversity of habitats for how well they function was investigated for the first time. The researchers set up an experiment with sediment cores combined into model ecosystems with different habitat diversity. Ecosystems with two or more habitats scored better in functionality than single-habitat ecosystems. This effect on ecosystem functioning has previously been recognized when communities differ in species diversity. Here, Alsterberg and colleagues show that the concept also applies to the diversity of habitats. Species and habitat diversity are both threatened by human activities. Habitat homogenization is commonly observed in many ecosystems worldwide. This study demonstrates that both species and habitat diversity are important to maintain a functional ecosystem and to predict feedbacks from natural and anthropogenic perturbations. A stronger focus on habitats could be relevant from a management perspective. Science Advances, article: Alsterberg C, Roger F, Sundbäck K, Juhansson J, Hulth S, Hallin S, Gamfeldt L (2017) "Habitat diversity and ecosystem multifunctionality--The importance of direct and indirect effects". (http://advances. )

News Article | December 19, 2016
Site: www.eurekalert.org

Researchers at the Chinese Academy of Sciences in Beijing and Uppsala University, Uppsala, Sweden have put together all known information about the endangered Rufous-headed Robin. Very few observations have been made since it was first discovered in 1905. The researchers suggest that its distribution might be larger than previously thought. - We have tried to estimate its potential distribution to find areas where it might occur but where it has not yet been observed. Since most of the potential new areas are in poorly accessible mountain ranges, we are hopeful that it has a larger distribution, and hence that it is less threatened than presently believed, says Professor Per Alstroem, Department of Ecology and Genetics, Uppsala University and Swedish Species Information Centre, Swedish University of Agricultral Sciences. The Rufous-headed Robin Larvivora ruficeps is related to the Common Nightingale Luscinia megarhynchos and Thrush Nightingale Luscinia luscinia. In common with these, it has a strong and beautiful song. However, unlike in the nightingales, males and females differ in plumage, and the male is strikingly coloured. In the present study, the researchers have summarized all known observations of the Rufous-headed Robin since it was first discovered in the summer of 1905 in the Shaanxi Province of central China. The second observation was not made until March 1963, in Malaysia. In June 1985, three singing males were discovered at one site in the Sichuan Province in central China. In the last 25 years, the Rufous-headed Robin has only been observed at his site and in a neighbouring nature reserve, with up to maximum 8 individuals in a year. It has also been seen twice in the non-breeding season in Southeast Asia. No observations were made in 2016, despite searches at the two classic sites. The potential distribution was estimated based on the species' known habitat preferences, and the researchers concluded that it might be more widespread than presently appreciated. Many of those areas have been poorly surveyed, so there is still hope that some unknown populations might be discovered. The reasons why the Rufous-headed Robin is so rare are unknown. The researchers analysed DNA from one Rufous-headed Robin and concluded that its closest relative is the Rufous-tailed Robin Larvivora sibilans, which breeds in Siberia and northeast China, whereas it is more distantly related to the two European nightingales. The song of the Rufous-headed Robin was also studied in detail, and it was found to be very different from the song of its closest relative, the Rufous-tailed Robin, whereas it is much more reminiscent of the song of the more distantly related Ryukyu Robin Larvivora komadori, from Japan. The study concluded that the similarity in song between the Rufous-headed and Ryukyu Robins is the result of so-called parallel evolution, and accordingly is not due to common ancestry. Professor Per Alstroem Department of Ecology and Genetics, Uppsala University and Swedish Species Information Centre, Swedish University of Agricultural Sciences Email: per.alstrom@ebc.uu.se Tel: +46 70 454 69 65 http://www. http://www. Zhao, M., Alstroem, P., Hu, R., Zhao, C., hao, Y., Lei, F. & Qu, Y. 2017. Phylogenetic relationships, song and distribution of the endangered Rufous-headed Robin Larvivora ruficeps. Ibis 159: 204-216.

De Riek J.,Belgium Institute for Agricultural and Fisheries Research | De Cock K.,Belgium Institute for Agricultural and Fisheries Research | Smulders M.J.M.,Wageningen UR Plant Breeding | Nybom H.,Swedish University of Agricultural Sciences
Molecular Phylogenetics and Evolution | Year: 2013

Within the genus Rosa numerous species have been described. Circumscription of the dogrose section Caninae is straightforward, but the delineation of species and subsections within this section is less clear, partly due to hybridisation between species. We have investigated the extent to which DNA marker-based information of wild populations corroborates present-day dogrose taxonomy and hypotheses about the origination of taxa. Sampling was conducted in a transect across Europe, collecting over 900 specimens of all encountered dogrose taxa. For comparison, we also included more than 200 samples of species belonging to other sections. Two lines of statistical analyses were used to investigate the genetic structure based on AFLP data: (1) an unstructured model with principal coordinate analysis and hierarchical clustering, and (2) a model with a superimposed taxonomic structure based on analysis of genetic diversity using a novel approach combining assignment tests with canonical discriminant analysis. Support was found for five of the seven subsections, whereas R. balsamica apparently belongs to subsection Caninae thus omitting the need for recognising subsection Tomentellae. For R. stylosa, a hybridogenic origin with a non-dogrose section member has been suggested, and it can be treated either as a separate subsection or within subsection Caninae. Within the subsection Rubigineae, a species cluster with low support for the taxa R. micrantha, R. rubiginosa and the putatively hybridogenous R. gremlii was identified. Similarly, several species in the subsection Caninae overlapped considerably, and are best regarded as one common species complex. This population genetic approach provides a general method to validate the taxonomic system in complex and polyploid taxa. © 2013 Elsevier Inc.

Perez S.,European Synchrotron Radiation Facility | Bertoft E.,Swedish University of Agricultural Sciences
Starch/Staerke | Year: 2010

Recent developments in methods and instrumentation have contributed to major advances in our understanding of the fine structure of amylose and amylopectin. The structure of the starch granule slowly unravels with new insight into key structural features. Following a brief presentation of the structural features common to all starches, the most recent findings for the structureof amylose and amylopectin are reported. The organizationof different types of chains in amylopectin is discussed with a critical review of the 'cluster' model leading to the presentation of alternative models. The locations of molecular components in the starch granule are described according to a progress structural order. The description of the crystalline components is followed by a presentation of their supramolecular arrangements. The crystalline components comprise platelet nanocrystals which have already been identified and characterized, and other less well characterized 'blocklet components'. The location and state of amylose within the granule isalso presented. This comprehensive review aimsat distinguishing between those structural features that have received widespread acceptance and those that are still under debate, with the ambition of being educational and to provide stimulation for further fundamental investigation into the starch granule as a macromolecular assembly. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Boonstra W.J.,Swedish University of Agricultural Sciences | Bach Dang N.,Hue University
Marine Policy | Year: 2010

Whether or not fishers comply with regulation depends on the economic and social context in which they operate their vessels. This is how conventional theory explains the phenomenon of non-compliance. It treats state-community interaction processes not as direct causes for non-compliance but rather as background conditions shaping individual fishers' perception and decisions for action. This paper argues that conventional theory fails to include the dynamics of tempo-relational processes between state and communities, which explains collective patterns of non-compliance in fisheries. The paper addresses this hiatus in the literature, using a process-sociological approach to analyse non-compliance in Vietnamese marine fisheries. The analysis highlights that Vietnamese marine fisheries are mainly regulated through informal networks of trust and mistrust, which function through their interplay with the highly centralised and formalised Vietnamese state. Based on this assessment, the paper concludes that outcomes of processes of the dynamic social interplay between state and communities are semi-dependent on individual perception and action, and as such have a causal effect of their own on patterns of non-compliance in fisheries. © 2010.

Aichinger E.,ETH Zurich | Aichinger E.,Albert Ludwigs University of Freiburg | Villar C.B.R.,ETH Zurich | di Mambro R.,University of Rome La Sapienza | And 3 more authors.
Plant Cell | Year: 2011

The chromatin modifying Polycomb group (PcG) and trithorax group (trxG) proteins are central regulators of cell identity that maintain a tightly controlled balance between cell proliferation and cell differentiation. The opposing activities of PcG and trxG proteins ensure the correct expression of specific transcriptional programs at defined developmental stages. Here, we report that the chromatin remodeling factor PICKLE (PKL) and the PcG protein CURLY LEAF (CLF) antagonistically determine root meristem activity. Whereas loss of PKL function caused a decrease in meristematic activity, loss of CLF function increased meristematic activity. Alterations of meristematic activity in pkl and clf mutants were not connected with changes in auxin concentration but correlated with decreased or increased expression of root stem cell and meristem marker genes, respectively. Root stem cell and meristem marker genes are modified by the PcG-mediated trimethylation of histone H3 on lysine 27 (H3K27me3). Decreased expression levels of root stem cell and meristem marker genes in pkl correlated with increased levels of H3K27me3, indicating that root meristem activity is largely controlled by the antagonistic activity of PcG proteins and PKL. © 2011 American Society of Plant Biologists.

Noll M.,Coburg University of Applied Sciences | Jirjis R.,Swedish University of Agricultural Sciences
Applied Microbiology and Biotechnology | Year: 2012

The demand of renewable energy sources, i.e. biomass, is steadily increasing worldwide to reduce the need of fossil energy sources. Biomass such as energy crops, woody species, forestry and agricultural residues are the most common renewable energy sources. Due to uneven demand for wood fuel, the material is mostly stored outdoors in chip piles or as logs until utilisation. Storage of biomass is accompanied by chemical, physical and biological processes which can significantly reduce the fuel quality. However, heating plants require high-quality biomass to ensure efficient operation, thereby minimising maintenance costs. Therefore, optimised storage conditions and duration times for chipped wood and tree logs have to be found. This paper aims at reviewing available knowledge on the pathways of microbial effects on stored woody biomass and on investigations of the fungal and bacterial community structure and identity. Moreover, potential functions of microorganisms present in wood chip piles and logs are discussed in terms of (1) reduction of fuel quality, (2) catalysing selfignition processes, and (3) constituting health risk and unfriendly work environment. © Springer-Verlag 2011.

Zavyalov V.,University of Turku | Zavialov A.,Swedish University of Agricultural Sciences | Zav'Yalova G.,University of Turku | Korpela T.,University of Turku
FEMS Microbiology Reviews | Year: 2010

This review summarizes current knowledge on the structure, function, assembly and biomedical applications of the superfamily of adhesive fimbrial organelles exposed on the surface of Gram-negative pathogens with the classical chaperone/usher machinery. High-resolution three-dimensional (3D) structure studies of the minifibers assembling with the FGL (having a long F1-G1 loop) and FGS (having a short F1-G1 loop) chaperones show that they exploit the same principle of donor-strand complementation for polymerization of subunits. The 3D structure of adhesive subunits bound to host-cell receptors and the final architecture of adhesive fimbrial organelles reveal two functional families of the organelles, respectively, possessing polyadhesive and monoadhesive binding. The FGL and FGS chaperone-assembled polyadhesins are encoded exclusively by the gene clusters of the γ3- and κ-monophyletic groups, respectively, while gene clusters belonging to the γ1-, γ2-, γ4-, and π-fimbrial clades exclusively encode FGS chaperone-assembled monoadhesins. Novel approaches are suggested for a rational design of antimicrobials inhibiting the organelle assembly or inhibiting their binding to host-cell receptors. Vaccines are currently under development based on the recombinant subunits of adhesins. © 2010 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Muller C.,Linköping University | Hamedi M.,Linköping University | Karlsson R.,Linköping University | Jansson R.,Swedish University of Agricultural Sciences | And 3 more authors.
Advanced Materials | Year: 2011

Woven electrochemical transistors on silk fibers from the silkworm Bombyx mori are demonstrated. This is achieved with carefully chosen electrolyte chem-istry: electrically conducting silk fibers are produced by dyeing silk fibers with a conjugated polyelectrolyte and gating is accomplished by use of an electro-lyte mixture composed of imidazolium-based ionic liquids. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Gothe E.,Swedish University of Agricultural Sciences | Angeler D.G.,Swedish University of Agricultural Sciences | Sandin L.,University of Aarhus
Journal of Animal Ecology | Year: 2013

Current ecological frameworks emphasize the relative importance of local and regional drivers for structuring species communities. However, most research has been carried out in systems with discrete habitat boundaries and a clear insular structure. Stream networks deviate from the insular structure and can serve as excellent model systems for studying hierarchical community dynamics over different temporal and spatial extents. We used benthic invertebrate data from streams in a small northern Swedish catchment to test whether metacommunity dynamics change between seasons, across spatial hierarchies (i.e. at the whole catchment scale vs. the scales of first-order and second/third-order sites within the catchment) and between stream-order groups. We assessed metacommunity structure as a function of three relevant dispersal dimensions (directional downstream processes, along-stream dispersal and overland dispersal). These dispersal dimensions were related to species groups with relevant dispersal traits (flying capacity, drift propensity) and dispersal capacities (weak vs. strong) to elucidate whether the observed spatial signals were due to dispersal limitation or mass effects. Results showed complex community organization that varied between seasons, with the scale of observation, and with stream order. The importance of spatial factors and specific dispersal dimensions was highly dependent on the time of sampling and the scale of observation. The importance of environmental factors was more consistent in our analyses, but their effect on species community structure peaked at first-order sites. Our analyses of species dispersal traits were not unequivocal, but indicated that both mass effects and dispersal limitation could simultaneously contribute to the spatial signal at the scale of the whole catchment through different dispersal pathways. We conclude that the study of hierarchically organized ecosystems uncovers complex patterns of metacommunity organization that may deviate substantially from those of systems with insular structure and discrete habitat boundaries. Moreover, we show that dispersal constraints imposed by the dendritic structure of stream networks and distinct dispersal mechanisms (e.g. dispersal limitation) may be evident also at very small spatial extents. Thus, even at this small scale, a landscape management approach that takes the dendritic nature of stream networks into account is needed to effectively conserve stream biodiversity. © 2012 The Authors. Journal of Animal Ecology © 2012 British Ecological Society.

Rasmussen M.K.,University of Aarhus | Zamaratskaia G.,Swedish University of Agricultural Sciences | Ekstrand B.,University of Aarhus
Reproduction in Domestic Animals | Year: 2011

Contents: In pigs, the hepatic cytochrome P450 (CYP) 1A2, 2A and 2E1 activity is important in the regulation of skatole accumulation in adipose tissue. This study investigated gender-related differences in CYP1A2, 2A and 2E1 dependent activity, protein and mRNA expression. This study also investigated the gonadal steroid dependent inhibition of CYP activity in relation to gender and dietary composition. Microsomes were prepared from the liver of female and entire male pigs (Landrace×Yorkshire sire and Duroc boars) reared under similar conditions and slaughtered at an age of 164days. A group of entire male pigs fed dried chicory root for 16days prior to slaughter were included in the study. CYP activities were assessed by the use of probe substrates, whilst mRNA and protein expression were analysed by RT-PCR and Western blotting. Furthermore inhibition of CYP dependent activity by gonadal steroids was assessed in vitro. Microsomes from female pigs had greater CYP1A2 and 2A activity, as well as mRNA expression compared to entire male pigs. The antibodies used did not detected differences in protein expression. In vitro inhibition by 17β-oestradiol, oestrone, androstenone and 3β-OH androstenol of CYP2E1 activity in microsomes from entire male pigs as well as inhibition of CYP1A activity in chicory fed entire male pigs was observed. Apart from that no effect of steroids was shown. In conclusion, female pigs show greater CYP activity and mRNA expression. Including chicory in the diet for 16days changed the gonadal steroid dependent inhibition of CYP activity in entire male pigs. © 2010 Blackwell Verlag GmbH.

Biswas A.K.,Lulea University of Technology | Rudolfsson M.,Swedish University of Agricultural Sciences | Brostrom M.,Umeå University | Umeki K.,Lulea University of Technology
Applied Energy | Year: 2014

This paper presents how pelletizing die temperature and moisture content affect combustion behaviour of single wood pellet. Pine wood particles with two different moisture contents (i.e. 1. wt.% and 12. wt.%) were pelletized in a laboratory-scale single pelletizer (single die pellets) at die temperature of 20, 100, 150 and 200. °C. The pellets were combusted in a laboratory scale furnace at 800. °C. Time required for single pellet combustion generally increased with both increase of pelletizing temperature and moisture content of biomass. In addition, combustion behaviour of single die pellets was significantly different than those produced in a pilot scale pelletizing plant (semi-industrial scale pellet). That difference was due to variation in physical properties of pellets (e.g. density, and morphology). © 2014 Elsevier Ltd.

Pi L.,Albert Ludwigs University of Freiburg | Aichinger E.,Albert Ludwigs University of Freiburg | van der Graaff E.,Albert Ludwigs University of Freiburg | Llavata-Peris C.I.,Wageningen University | And 4 more authors.
Developmental Cell | Year: 2015

Stem cells in plants and animals are maintained pluripotent by signals from adjacent niche cells. In plants, WUSCHEL HOMEOBOX (WOX) transcription factors are central regulators of stem cell maintenance in different meristem types, yet their molecular mode of action has remained elusive. Here we show that in the Arabidopsis root meristem, the WOX5 protein moves from the root niche organizer, the quiescent center, into the columella stem cells, where it directly represses the transcription factor gene CDF4. This creates a gradient of CDF4 transcription, which promotes differentiation opposite to the WOX5 gradient, allowing stem cell daughter cells to exit the stem cell state. We further show that WOX5 represses CDF4 transcription by recruiting TPL/TPR co-repressors and the histone deacetylase HDA19, which consequently induces histone deacetylation at the CDF4 regulatory region. Our results show that chromatin-mediated repression of differentiation programs is a common strategy in plant and animal stem cell niches. © 2015 Elsevier Inc.

Nilsson J.,Swedish University of Agricultural Sciences | Svendsen G.L.,University of Southern Denmark | Svendsen G.T.,University of Aarhus
Agribusiness | Year: 2012

During the last 20 years many traditionally organized agricultural cooperatives have been forced to abandon their business form. Explanations have been put forward, comprising a variety of economic and sociological theories. The present study suggests that the social capital paradigm may add explanatory power when analyzing this development. It is claimed that the problems are due to the members having increasingly little trust in the cooperatives and in each other. The cooperatives' decision makers have no instruments for estimating how much social capital is lost when they pursue strategies of vertical and horizontal integration. Therefore, they do not consider this loss in their calculations. Thus, the problems caused by the cooperatives' vaguely defined property rights are becoming increasingly serious. This reasoning is summarized into a model, which is influenced by the consumer choice model. © 2012 Wiley Periodicals, Inc.

Weyhenmeyer G.A.,Swedish University of Agricultural Sciences | Jeppesen E.,University of Aarhus
Global Change Biology | Year: 2010

With a unique data set comprising 1041 boreal forested and low human impacted lakes included in three Swedish lake inventories for 1995, 2000 and 2005 and with time series for 12 of the lakes from 1988 to 2008 we show that nitrate-nitrogen (NO3-N) is accumulated in freshwaters along with increasing atmospheric nitrogen deposition (Ndep). At the same time we observe decreasing DOC: NO3-N ratios in the water column. We suggest that NO3-N is accumulated in freshwaters when denitrifying bacteria are limited by their energy source rather than the availability of NO3-N, i.e. at low DOC: NO3-N ratios. We obtained further support for a close relationship between Ndep driven DOC: NO3-N ratios and the efficiency of nitrate removal by using a published global data set on measured nitrate removal rates in unproductive reference streams. Owing to the currently decreasing Ndep in large regions of, for instance, Northern Europe, this process is now reversed, resulting in increasing DOC: NO3-N ratios and more efficient nitrate removal from freshwaters. Depending on NOx emissions, nitrogen limited regions may expand with an immediate effect on nitrate concentrations in freshwaters. © 2009 Blackwell Publishing Ltd.

McGoff E.,Swedish University of Agricultural Sciences | Sandin L.,University of Aarhus
Fundamental and Applied Limnology | Year: 2012

Lake habitat alteration is a major stressor for lakes worldwide, and physical habitat alteration is likely the biggest threat to aquatic ecosystems, exceeding all other anthropogenic pressures. This study sought to elucidate which group of variables was the most important for describing Swedish macroinvertebrate community structure: trophic status, substrate variables or riparian variables. We also investigated what influence each of these groups of variables has on the other. The impact of large scale land use patterns was also investigated, to determine if macroinvertebrates responded differently in two different catchment land use types: impaired and unimpaired. Partial canonical ordination analysis showed that substrate variables were the most important for describing macroinvertebrate community variation in both catchment land use classes, followed by riparian descriptors, with the trophic signal only becoming clear when lakes were more strongly stratified for coarseness of substrate. This trophic effect was only evident in the impaired lakes, as the trophic gradient was much shorter in the lakes with an unimpaired catchment. Our results suggest that trophic effects on benthic invertebrates are nested within substrate habitat effects, and were masked by local habitat heterogeneity. This indicates that, at least in the Swedish situation, greater care needs to be taken in stratifying the substrate sampled in order to see this nutrient pressure-macroinvertebrate response relationship. The macroinvertebrate community composition was also responding to changes in riparian vegetation, specifically the presence of riparian trees and canopy cover. These variables, or lack of, are possible proxies for anthropogenic alteration of lake shores. Therefore, although macroinvertebrates may not be strong indicators of trophic pressure in all cases or habitats, they may be useful indicators for other anthropogenic pressures (e.g. hydromorphology) on lake shores. © 2012 E. Schweizerbart'sche Verlagsbuchhandlung, Stuttgart, Germany.

Sundqvist M.K.,Swedish University of Agricultural Sciences | Sanders N.J.,University of Tennessee at Knoxville | Sanders N.J.,Rocky Mountain Biological Laboratory | Sanders N.J.,Copenhagen University | Wardle D.A.,Swedish University of Agricultural Sciences
Annual Review of Ecology, Evolution, and Systematics | Year: 2013

Community structure and ecosystem processes often vary along elevational gradients. Their responses to elevation are commonly driven by changes in temperature, and many community- and ecosystem-level variables therefore frequently respond similarly to elevation across contrasting gradients. There are also many exceptions, sometimes because other factors such as precipitation can also vary with elevation. Given this complexity, our capacity to predict when and why the same variable responds differently among disparate elevational gradients is often limited. Furthermore, there is utility in using elevational gradients for understanding community and ecosystem responses to global climate change at much larger spatial and temporal scales than is possible through conventional ecological experiments. However, future studies that integrate elevational gradient approaches with experimental manipulations will provide powerful information that can improve predictions of climate change impacts within and across ecosystems. © Copyright ©2013 by Annual Reviews. All rights reserved.

Lundmark R.,Lulea University of Technology | Athanassiadis D.,Swedish University of Agricultural Sciences | Wetterlund E.,Lulea University of Technology
Biomass and Bioenergy | Year: 2015

As there is increasing interest in the use of biomass for energy in Sweden, the potential availability and harvesting costs of forest roundwood, harvesting residues and stumps were estimated up to the year 2069 in 10-year intervals, using a high spatial resolution GIS. In each individual forest area, an average harvesting cost per forest assortment was estimated, based on the geographic and other properties of the area. Using cost structure and resource availability, marginal cost curves were constructed to allow analyses of the effects of changing market conditions and different policy frameworks. Based on geographically explicit data, the results indicated that the average harvesting costs would be 21-24€m-3 for roundwood, depending on the type of harvesting and extraction operation. The corresponding cost estimate for harvesting residues was 23-25€m-3 and 35€m-3 for stumps. The harvesting cost estimates lie on the steeper part of the marginal cost curve, suggesting that increases in the supply of woody biomass can only occur at significantly higher harvesting costs. From a policy perspective, this suggests that subsidies aimed at reducing the harvesting costs will only have limited success in increasing the harvested volumes, given current technology. Therefore, for future development in the supply of forest assortments for energy generation, it is important to consider not only the supply potential, but also the integration of improvements in harvesting and transportation systems. © 2015 Elsevier Ltd.

Soane B.D.,Crachin | Ball B.C.,Crop and Soil Systems Research Group | Arvidsson J.,Swedish University of Agricultural Sciences | Basch G.,University of Évora | And 2 more authors.
Soil and Tillage Research | Year: 2012

Recent literature on no-till is reviewed with particular emphasis on research on commercial uptake and environmental concerns in northern, western and south-western Europe. Increased interest in no-till, and minimum or reduced tillage, results from changes in the economic circumstances of crop production, the opportunity to increase the area of more profitable autumn-sown crops and increased concern about environmental damage associated with soil inversion by ploughing. Highly contrasting soil and climate types within and between these regions exert a strong influence on the success of no-till. While no-till may often result in crop yields which equal or exceed those obtained after ploughing, modest reductions in yield may be tolerated if production costs are lower than with ploughing. The relative costs of fuel and herbicides have changed appreciably in recent years making no-till more attractive commercially. While effective weed control is an essential aspect of no-till, current herbicide technology may not yet fully achieve this.In northern regions no-till usually allows earlier drilling of winter-sown crops but will give lower soil temperature and higher moisture content in spring, causing delayed drilling of spring-sown crops. No-till soils have greater bulk density and bearing capacity than ploughed soils with a pronounced vertical orientation of macroporosity allowing penetration of roots and water, especially in view of the increased population of deep-burrowing earthworms. Particular care must be taken with no-till to minimise soil damage at harvest and to ensure the even distribution of crop residues prior to drilling.Reduced erosion and runoff after adoption of no-till are widely observed and are of particular importance in southwestern Europe. No-till reduces losses of phosphorus in runoff and, in some cases, reduces the loss of nitrate through leaching. Emissions of greenhouse gases CO 2 and N 2O from no-till soils are highly variable and depend on complex interactions of soil properties. Emission of CO 2 from fuel during machinery usage is always appreciably reduced with no-till. Increased soil organic carbon in surface layers of no-till soils is widely found but may not be associated with increased carbon sequestration throughout the profile. The evaluation of the relative carbon balance for no-till and ploughing depends upon complex inter-relationships between soil and climate factors which are as yet poorly understood. Adoption of no-till could be encouraged by government financial assistance in recognition of environmental benefits, although future restrictions on the use of herbicides may be a deterrent. Opportunities for further research on no-till are outlined. © 2011 Elsevier B.V.

Schelker J.,Swedish University of Agricultural Sciences | Burns D.A.,U.S. Geological Survey | Weiler M.,Albert Ludwigs University of Freiburg | Laudon H.,Swedish University of Agricultural Sciences
Journal of Geophysical Research: Biogeosciences | Year: 2011

The mobilization of mercury and dissolved organic carbon (DOC) during snowmelt often accounts for a major fraction of the annual loads. We studied the role of hydrological connectivity of riparian wetlands and upland/wetland transition zones to surface waters on the mobilization of Hg and DOC in Fishing Brook, a headwater of the Adirondack Mountains, New York. Stream water total mercury (THg) concentrations varied strongly (mean = 2.25 ± 0.5 ng L -1), and the two snowmelt seasons contributed 40% (2007) and 48% (2008) of the annual load. Methyl mercury (MeHg) concentrations ranged up to 0.26 ng L-1, and showed an inverse log relationship with discharge. TOPMODEL-simulated saturated area corresponded well with wetland areas, and the application of a flow algorithm based elevation-above-creek approach suggests that most wetlands become well connected during high flow. The dynamics of simulated saturated area and soil storage deficit were able to explain a large part of the variation of THg concentrations (r2 = 0.53 to 0.72). In contrast, the simulations were not able to explain DOC variations and DOC and THg concentrations were not correlated. These results indicate that all three constituents, THg, MeHg, and DOC, follow different patterns at the outlet: (1) the mobilization of THg is primarily controlled by the saturation state of the catchment, (2) the dilution of MeHg suggests flushing from a supply limited pool, and (3) DOC dynamics follow a pattern different from THg dynamics, which likely results from differing gain and/or loss processes for THg and/or DOC within the Fishing Brook catchment. Copyright 2011 by the American Geophysical Union.

Jacobson K.,Swedish University of Agricultural Sciences | Myhr A.I.,GenOk Center for Biosafety
Journal of Environment and Development | Year: 2013

There is currently limited knowledge about the effects of introducing genetically modified (GM) crops into smallholder farming or about how biosafety requirements are interpreted and adopted by smallholders. A case study was conducted on introduction of GM (Bt) maize to South African smallholders. The results reveal low general awareness about agricultural technology among smallholders and an incompatibility between smallholder practices and biosafety requirements. The implications are low understanding of biosafety measures and low compliance. Therefore, essential prerequisites for the safe introduction of GM crops to smallholders are increased smallholder knowledge on modern plant varieties and improved agricultural advisory services that better match the smallholder context. In addition, information about GM crops and biosafety implementation must be modified to better suit smallholders. © The Author(s) 2012.

Agency: Cordis | Branch: FP7 | Program: CP | Phase: ICT-2013.6.5 | Award Amount: 5.35M | Year: 2013

The objective of the project is to develop co-operative mobility technologies for supervised vehicle platooning, in order to improve fuel efficiency and safety for goods transport. The potential social and environmental benefits inducted by heavy-duty vehicle platoons (or road trains) have been largely proven. However, until now, the creation, coordination, and operation of such platoons have been mostly neglected. In addition, the regulation and standardization of coordinated, together with its acceptance by the end-users and the society need further attention and research. The proposed idea is to develop a new energy-efficient and user-friendly integrated framework to coordinated driving of heavy-duty vehicles.We propose a new real-time coordination system, which will define an optimized flow of vehicles in order to dynamically create, maintain and dissolve platoons according to an online decision-making mechanism, taking into account also historical and real-time information about the state of the infrastructure. With such a technology, platoons will be no more composed just of vehicles with common origins and destinations, but they will be created dynamically on the road, by merging vehicles (or sub-platoons) that share also only subparts of their routes. The proposed idea is therefore a novel enabling technology with the potential to revolutionise todays freight logistics and overall transportation infrastructure.

Agency: Cordis | Branch: FP7 | Program: CP | Phase: ICT-2007.6.2 | Award Amount: 14.14M | Year: 2008

The objectives of the TeleFOT project are to assess the impacts of functions provided by aftermarket and nomadic devices in vehicles and raise wide awareness of their traffic safety potential. These devices can provide different types of driver support functions and almost nothing is known about their safety and other impacts yet. The market penetration of portable navigators and smart phones is exploding today. The timing for the project is ideal. The functions to be tested cover two broad areas: Functions promoting (i) safe driving and (ii) economic and fuel efficient driving. These are Speed information, Traffic information, Road weather information and Green driving support. The impacts are assessed on levels ranging from usability; behaviour and incidents; safety; Green Driving and efficiency; to the impacts on the transport system. Attention will be also paid to possible negative impacts, since especially smart phones are not originally designed for vehicle use and navigators may have problems in fixing and positioning in the cockpit. The project also aims at speeding up the penetration of systems able to see beyond drivers field of vision in conditions where good situation awareness is needed. TeleFOT provides opportunities to test the impacts of similar functions future cooperative systems will provide after their development challenges have been solved in the coming years. In fact, aftermarket and nomadic devices provide an alternative to some important cooperative driving and ADAS functions for many years ahead. The concept comprises of creating three European test communities: Northern, Central and Southern. About 3 000 drivers participate in the tests. The project has strong national support and no resources are needed for setting up the testing infrastructures. Business models are also studied. Owing to very different traffic behaviour and reactions to safety measures in Europe, it is necessary to have test communities spanning from south to north.

Lee M.-H.,National Taiwan University | Wang L.,Swedish University of Agricultural Sciences | Chang Z.-F.,National Taiwan University | Chang Z.-F.,National Yang Ming University
Nucleic Acids Research | Year: 2014

In quiescent fibroblasts, the expression levels of cytosolic enzymes for thymidine triphosphate (dTTP) synthesis are down-regulated, causing a marked reduction in the dTTP pool. In this study, we provide evidence that mitochondrial thymidylate synthesis via thymidine kinase 2 (TK2) is a limiting factor for the repair of ultraviolet (UV) damage in the nuclear compartment in quiescent fibroblasts. We found that TK2 deficiency causes secondary DNA double-strand breaks formation in the nuclear genome of quiescent cells at the late stage of recovery from UV damage. Despite slower repair of quiescent fibroblast deficient in TK2, DNA damage signals eventually disappeared, and these cells were capable of re-entering the S phase after serum stimulation. However, these cells displayed severe genome stress as revealed by the dramatic increase in 53BP1 nuclear body in the G1 phase of the successive cell cycle. Here, we conclude that mitochondrial thymidylate synthesis via TK2 plays a role in facilitating the quality repair of UV damage for the maintenance of genome integrity in the cells that are temporarily arrested in the quiescent state. © 2014 © The Author(s) 2014. Published by Oxford University Press.

Naddafi R.,Swedish University of Agricultural Sciences | Rudstam L.G.,Cornell University
PLoS ONE | Year: 2013

Cascading trophic interactions are often defined as the indirect effects of a predator on primary producers through the effect of the predator on herbivores. These effects can be both direct through removal of herbivores [density-mediated indirect interactions (DMIIs)] or indirect through changes in the behavior of the herbivores [trait-mediated indirect interactions (TMIIs)]. How the relative importance of these two indirect interactions varies with predator diversity remains poorly understood. We tested the effect of predator diversity on both TMIIs and DMIIs on phytoplankton using two competitive invasive dreissenid mussel species (zebra mussel and quagga mussel) as the herbivores and combinations of one, two or all three species of the predators pumpkinseed sunfish, round goby, and rusty crayfish. Predators had either direct access to mussels and induced both TMII and DMII, or no direct access and induced only TMII through the presence of risk cues. In both sets of treatments, the predators induced a trophic cascade which resulted in more phytoplankton remaining with predators present than with only mussels present. The trophic cascade was weaker in three-predator and two-predator treatments than in one-predator treatments when predators had direct access to dreissenids (DMIIs and TMIIs). Crayfish had higher cascading effects on phytoplankton than both pumpkinseed and round goby. Increased predator diversity decreased the strength of DMIIs but had no effect on the strength of TMIIs. The strength of TMIIs was higher with zebra than quagga mussels. Our study suggests that inter-specific interference among predators in multi-species treatments weakens the consumptive cascading effects of predation on lower trophic levels whereas the importance of predator diversity on trait mediated effects depends on predator identity. © 2013 Naddafi and Rudstam.

Sakuma S.,Japan National Institute of Agrobiological Science | Sakuma S.,Chiba University | Salomon B.,Swedish University of Agricultural Sciences | Komatsuda T.,Japan National Institute of Agrobiological Science
Plant and Cell Physiology | Year: 2011

The process of crop domestication began 10,000 years ago in the transition of early humans from hunter/gatherers to pastoralists/farmers. Recent research has revealed the identity of some of the main genes responsible for domestication. Two of the major domestication events in barley were (i) the failure of the spike to disarticulate and (ii) the six-rowed spike. The former mutation increased grain yield by preventing grain loss after maturity, while the latter resulted in an up to 3-fold increase in yield potential. Here we provide an overview of the disarticulation systems and inflorescence characteristics, along with the genes underlying these traits, occurring in the Triticeae tribe. © 2011 The Author.

Sairanen I.,Swedish University of Agricultural Sciences | Novak O.,Swedish University of Agricultural Sciences | Pencik A.,Swedish University of Agricultural Sciences | Ikeda Y.,Umeå University | And 4 more authors.
Plant Cell | Year: 2013

Plants are necessarily highly competitive and have finely tuned mechanisms to adjust growth and development in accordance with opportunities and limitations in their environment. Sugars from photosynthesis form an integral part of this growth control process, acting as both an energy source and as signaling molecules in areas targeted for growth. The plant hormone auxin similarly functions as a signaling molecule and a driver of growth and developmental processes. Here, we show that not only do the two act in concert but that auxin metabolism is itself regulated by the availability of free sugars. The regulation of the biosynthesis and degradation of the main auxin, indole-3-acetic acid (IAA), by sugars requires changes in the expression of multiple genes and metabolites linked to several IAA biosynthetic pathways. The induction also involves members of the recently described central regulator PHYTOCHROME-INTERACTING FACTOR transcription factor family. Linking these three known regulators of growth provides a model for the dynamic coordination of responses to a changing environment. © 2012 American Society of Plant Biologists.

Bartomeus I.,Rutgers University | Bartomeus I.,Swedish University of Agricultural Sciences | Park M.G.,Cornell University | Gibbs J.,Cornell University | And 4 more authors.
Ecology Letters | Year: 2013

Climate change has the potential to alter the phenological synchrony between interacting mutualists, such as plants and their pollinators. However, high levels of biodiversity might buffer the negative effects of species-specific phenological shifts and maintain synchrony at the community level, as predicted by the biodiversity insurance hypothesis. Here, we explore how biodiversity might enhance and stabilise phenological synchrony between a valuable crop, apple and its native pollinators. We combine 46 years of data on apple flowering phenology with historical records of bee pollinators over the same period. When the key apple pollinators are considered altogether, we found extensive synchrony between bee activity and apple peak bloom due to complementarity among bee species' activity periods, and also a stable trend over time due to differential responses to warming climate among bee species. A simulation model confirms that high biodiversity levels can ensure plant-pollinator phenological synchrony and thus pollination function. © 2013 John Wiley & Sons Ltd/CNRS.

Poeplau C.,Thuenen Institute of Climate Smart Agriculture | Poeplau C.,Swedish University of Agricultural Sciences | Don A.,Thuenen Institute of Climate Smart Agriculture
Agriculture, Ecosystems and Environment | Year: 2015

A promising option to sequester carbon in agricultural soils is the inclusion of cover crops in cropping systems. The advantage of cover crops as compared to other management practices that increase soil organic carbon (SOC) is that they neither cause a decline in yields, like extensification, nor carbon losses in other systems, like organic manure applications may do. However, the effect of cover crop green manuring on SOC stocks is widely overlooked. We therefore conducted a meta-analysis to derive a carbon response function describing SOC stock changes as a function of time. Data from 139 plots at 37 different sites were compiled. In total, the cover crop treatments had a significantly higher SOC stock than the reference croplands. The time since introduction of cover crops in crop rotations was linearly correlated with SOC stock change (R2=0.19) with an annual change rate of 0.32±0.08Mgha-1yr-1 in a mean soil depth of 22cm and during the observed period of up to 54 years. Elevation above sea level of the plot and sampling depth could be used as explanatory variables to improve the model fit. Assuming that the observed linear SOC accumulation would not proceed indefinitely, we modeled the average SOC stock change with the carbon turnover model RothC. The predicted new steady state was reached after 155 years of cover crop cultivation with a total mean SOC stock accumulation of 16.7±1.5Mgha-1 for a soil depth of 22cm. Thus, the C input driven SOC sequestration with the introduction of cover crops proved to be highly efficient. We estimated a potential global SOC sequestration of 0.12±0.03PgCyr-1, which would compensate for 8% of the direct annual greenhouse gas emissions from agriculture. However, altered N2O emissions and albedo due to cover crop cultivation have not been taken into account here. Data on those processes, which are most likely species-specific, would be needed for reliable greenhouse gas budgets. © 2014 Elsevier B.V.

Kardol P.,University of Tennessee at Knoxville | Kardol P.,Swedish University of Agricultural Sciences | Souza L.,University of Tennessee at Knoxville | Classen A.T.,University of Tennessee at Knoxville
Oikos | Year: 2013

Assembly history, including the order in which species arrive into a community, can influence long-term community structure; however we know less about how timing of species arrival may alter assembly especially under varying resource conditions. To explore how the timing of species arrival interacts with resource availability to alter community assembly, we constructed experimental plant communities and manipulated the interval between plantings of groups of seedlings (0, 5, 10, 15 or 20 days) at low and high levels of soil nutrient supply. To see if community changes influenced ecosystem-scale processes, we measured parameters across the plant-soil continuum (e.g. plant biomass and net ecosystem carbon dioxide exchange). We found that the timing of species arrival had a large impact on community assembly, but the size of the effect depended on soil fertility. As planting interval increased, plant communities diverged further from the control, but the divergence was stronger at high than at low nutrient supply. Our data suggest that at high nutrient supply, early-planted species preempted light resources more quickly, thus preventing the successful establishment of later arriving species even at short planting intervals. Finally, we found that assembly related divergence in plant communities scaled to impact ecosystem-level characteristics such as green leaf chemistry, but had little effect on total community biomass and net ecosystem exchange of CO2 and water vapor. Our data indicate that the effect of a stochastic factor, here the timing of species arrival on community composition, depends on the resource level under which the community assembles. © 2012 The Authors. Oikos © 2012 Nordic Society Oikos.

Andrade S.C.,Harvard University | Montenegro H.,University of Sao Paulo | Strand M.,Swedish University of Agricultural Sciences | Schwartz M.L.,University of Washington | And 5 more authors.
Molecular biology and evolution | Year: 2014

Resolving the deep relationships of ancient animal lineages has proven difficult using standard Sanger-sequencing approaches with a handful of markers. We thus reassess the relatively well-studied phylogeny of the phylum Nemertea (ribbon worms)-for which the targeted gene approaches had resolved many clades but had left key phylogenetic gaps-by using a phylogenomic approach using Illumina-based de novo assembled transcriptomes and automatic orthology prediction methods. The analysis of a concatenated data set of 2,779 genes (411,138 amino acids) with about 78% gene occupancy and a reduced version with 95% gene occupancy, under evolutionary models accounting or not for site-specific amino acid replacement patterns results in a well-supported phylogeny that recovers all major accepted nemertean clades with the monophyly of Heteronemertea, Hoplonemertea, Monostilifera, being well supported. Significantly, all the ambiguous patterns inferred from Sanger-based approaches were resolved, namely the monophyly of Palaeonemertea and Pilidiophora. By testing for possible conflict in the analyzed supermatrix, we observed that concatenation was the best solution, and the results of the analyses should settle prior debates on nemertean phylogeny. The study highlights the importance, feasibility, and completeness of Illumina-based phylogenomic data matrices. © The Author 2014. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Chen Y.-L.,National Taiwan University | Eriksson S.,Swedish University of Agricultural Sciences | Chang Z.-F.,National Taiwan University | Chang Z.-F.,National Yang Ming University
Journal of Biological Chemistry | Year: 2010

Cellular supply of dNTPs is essential in the DNA replication and repair processes. Here we investigated the regulation of thymidine kinase 1 (TK1) in response to DNA damage and found that genotoxic insults in tumor cells cause up-regulation and nuclear localization of TK1. During recovery from DNA damage, TK1 accumulates in p53-null cells due to a lack of mitotic proteolysis as these cells are arrested in the G2 phase by checkpoint activation. We show that in p53-proficient cells, p21 expression in response to DNA damage prohibits G1/S progression, resulting in a smaller G2 fraction and less TK1 accumulation. Thus, the p53 status of tumor cells affects the level of TK1 after DNA damage through differential cell cycle control. Furthermore, it was shown that in HCT-116 p53-/- cells, TK1 is dispensable for cell proliferation but crucial for dTTP supply during recovery from DNA damage, leading to better survival. Depletion of TK1 decreases the efficiency of DNA repair during recovery from DNA damage and generates more cell death. Altogether, our data suggest that more dTTP synthesis via TK1 take place after genotoxic insults in tumor cells, improving DNA repair during G2 arrest. © 2010 by The American Society for Biochemistry and Molecular Biology, Inc.

Lindahl B.D.,Swedish University of Agricultural Sciences | De Boer W.,Netherlands Institute of Ecology | Finlay R.D.,Swedish University of Agricultural Sciences
ISME Journal | Year: 2010

Ectomycorrhizal fungi dominate the humus layers of boreal forests. They depend on carbohydrates that are translocated through roots, via fungal mycelium to microsites in the soil, wherein they forage for nutrients. Mycorrhizal fungi are therefore sensitive to disruptive disturbances that may restrict their carbon supply. By disrupting root connections, we induced a sudden decline in mycorrhizal mycelial abundance and studied the consequent effects on growth and activity of free living, saprotrophic fungi and bacteria in pine forest humus, using molecular community analyses in combination with enzyme activity measurements. Ectomycorrhizal fungi had decreased in abundance 14 days after root severing, but the abundance of certain free-living ascomycetes was three times higher within 5 days of the disturbance compared with undisturbed controls. Root disruption also increased laccase production by an order of magnitude and cellulase production by a factor of 5. In contrast, bacterial populations seemed little affected. The results indicate that access to an external carbon source enables mycorrhizal fungi to monopolise the humus, but disturbances may induce rapid growth of opportunistic saprotrophic fungi that presumably use the dying mycorrhizal mycelium. Studies of such functional shifts in fungal communities, induced by disturbance, may shed light on mechanisms behind nutrient retention and release in boreal forests. The results also highlight the fundamental problems associated with methods that study microbial processes in soil samples that have been isolated from living roots. © 2010 International Society for Microbial Ecology All rights reserved.

Naddafi R.,Swedish University of Agricultural Sciences | Rudstam L.G.,Cornell University
Freshwater Biology | Year: 2014

Summary: Induced morphological defences as a response to chemical cues from predators are common in aquatic systems. We evaluated predator-induced defences and the costs of these responses measured as growth rate reductions in two invasive mussel species. One mussel species (quagga mussel, Dreissena rostriformis bugensis) often dominates the other (zebra mussel, Dreissena polymorpha) in lakes where they co-occur. We exposed both species to cues from three important North American predators: round goby (Neogobius melanostomus), which is native in the ancestral range of the mussels, and pumpkinseed sunfish (Lepomis gibbosus) and rusty crayfish (Orconectes rusticus) that are native in North America. Both mussel species responded to risk cues by increasing shell thickness and decreasing growth rates. The response to round goby was smaller than the response to the two new predators. The strength of the induced response was negatively correlated with growth in both mussel species and both the strength of the induced defence and the decrease in growth were larger for zebra mussels than for quagga mussels. Survival was higher in zebra mussels than in quagga mussels, but there was no significant difference in survival among different risk cue treatments. The lower response and correlated faster growth of quagga mussels than zebra mussels in response to risk cues may be an additional reason for the replacement of zebra mussels by quagga mussels in North America, at least as long as native predators are not a major source of mortality. If true, we predict that both mussel species will co-occur after the exotic round goby becomes a dominant mussel predator in North America. © 2013 John Wiley & Sons Ltd.

Naddafi R.,Swedish University of Agricultural Sciences | Rudstam L.G.,Cornell University
Hydrobiologia | Year: 2014

The enemy release hypothesis states that invasive species are successful in their new environment because native species are not adapted to utilize the invasive. If true for predators, native predators should have lower feeding rates on the invasive species than a predator from the native range of the invasive species. We tested this hypothesis for zebra mussel (Dreissena polymorpha) by comparing handling time and predation rate on zebra mussels in the laboratory by two North American species (pumpkinseed, Lepomis gibbosus, and rusty crayfish, Orconectes rusticus) and one predator with a long evolutionary history with zebra mussels (round goby, Neogobius melanostomus). Handling time per mussel (7 mm shell length) ranged from 25 to >70 s for the three predator species. Feeding rates on attached zebra mussels were higher for round goby than the two native predators. Medium and large gobies consumed 50-67 zebra mussels attached to stones in 24 h, whereas pumpkinseed and rusty crayfish consumed <11. This supports the hypothesis that the rapid spread of zebra mussels in North America was facilitated by low predation rates from the existing native predators. At these predation rates and realistic goby abundance estimates, round goby could affect zebra mussel abundance in some lakes. © 2013 Springer Science+Business Media Dordrecht.

Naddafi R.,Swedish University of Agricultural Sciences | Rudstam L.G.,Cornell University
Animal Behaviour | Year: 2013

Predators induce behavioural defences in a large range of prey species, including molluscs. The ability of a species to respond appropriately to risk cues may determine the outcome of interspecific competition. We investigated whether two invasive mussel species, the zebra mussel, Dreissena polymorpha, and the quagga mussel, Dreissena rostriformis bugensis, differ in their behavioural responses to risk cues released from round goby, Neogobius melanostomus, pumpkinseed sunfish, Lepomis gibbosus, and rusty crayfish, Orconectes rusticus. In response to risk cues, both species increased their attachment strength, aggregated more, increased the use of a refuge habitat and decreased clearance rates. Although attachment strength, aggregation rate and refuge habitat use was greater for zebra than for quagga mussels, the strength of predator-induced responses was similar in the two mussel species for all behaviours except for filtering activity. Zebra mussels decreased clearance rates more when exposed to predator risk cues than quagga mussels. Both mussels decreased clearance rates the most with rusty crayfish risk cues present. Since these responses have a fitness cost associated with lower growth rates, the stronger response of zebra mussels may make this species competitively inferior to quagga mussels in an initial low-predation environment when few native predators are feeding on these mussels. This advantage may shift to zebra mussels over time if native predators learn or adapt to feed on the dreissenids. © 2013 The Association for the Study of Animal Behaviour.

Kurokawa H.,Tohoku University | Peltzer D.A.,Landcare Research | Wardle D.A.,Swedish University of Agricultural Sciences
Functional Ecology | Year: 2010

Summary: 1. Non-native invasive and nitrogen (N)-fixing plant species can cause large ecosystem-level impacts, particularly when they differ in functionally important plant traits from native and non N-fixing species. However, it remains unclear as to whether and how plant invasion status and N fixation ability consistently influence key plant leaf and litter traits, and trait-driven processes like herbivory and decomposition. 2. We compared leaf and litter traits, leaf palatability and litter decomposability for 41 co-occurring woody species, including native N-fixers, native non N-fixers, invasive N-fixers and invasive non N-fixers, from a New Zealand floodplain. We tested the hypotheses that: (i) invasive and N-fixing species have higher foliar N and specific leaf area, and lower concentrations of defensive phenolics and structural compounds than do native and non N-fixing species, and (ii) invasive and N-fixing species generally produce more decomposable litter and palatable foliage than do native and non N-fixing species. 3. Consistent with our hypotheses, invaders had higher foliar N and N: P ratio, and lower C: N ratio, than did native species. However, in contrast to our hypotheses, foliar phenolics were higher for the invaders while other leaf and litter traits were unaffected by invasion status. Further, N-fixers had higher N and N: P ratios, and lower C: N ratios than did non N-fixers, but other leaf and litter traits were unaffected by N fixation ability. 4. Leaf palatability was unaffected by invasion status but was higher for N-fixers than for non N-fixers. Litter decomposability was unaffected both by invasion status and N fixation ability. We found a significant positive relationship between leaf palatability and litter decomposability across all species, because similar traits, particularly the C: P ratio and total phenolic concentrations of plant tissues, were correlated with both processes. 5. Our results demonstrate that a small number of key traits, such as C: P ratio and total phenolic concentrations, drive both herbivory and decomposition irrespective of plant invasion status or N fixation ability. As such, they highlight that interspecific differences in particular plant traits, rather than plant functional group memberships based on invasion status and N fixation ability, are more effective in predicting palatability and decomposability. © 2009 The Authors. Journal compilation © 2009 British Ecological Society.

Gustafsson L.,Swedish University of Agricultural Sciences | Fedrowitz K.,Swedish University of Agricultural Sciences | Hazell P.,Swedish Forest Agency
Forest Ecology and Management | Year: 2013

Industrial forestry has caused large biodiversity changes in European boreal forests. One recently introduced conservation measure in production forestry is retention of trees at clearcutting to benefit flora and fauna. Aspen Populus tremula is often retained for conservation purposes since it is a key tree species for biodiversity with many associated species, a number of which are red-listed. Still, the importance to biodiversity of aspen trees retained at harvest is largely unknown. In 1994, a transplantation experiment with the old-growth forest indicator lichen Lobaria pulmonaria was set up on 280 aspens at 35 sites in east-central Sweden with a total of 1120 transplants, with the aim to assess the habitat suitability of retained aspens following harvest. After 14. years 23% of L. pulmonaria transplants remained, with a significantly higher survival on retained aspens than on aspens in the surrounding forest, especially on the northern side of stems. Transplants were also more vital on northern than on southern sides of stems. There was no difference in survival or vitality of transplants between dispersed aspens and aspens in groups. Results largely agreed with a re-inventory made already after two years but the importance of the north side of retention trees became evident for species survival only after 14. years, indicating that to gain deeper insights longer time-spans may be necessary. This study, which is the longest lichen transplantation time-series from a well replicated experiment so far published, shows that retention of trees at harvest may be an efficient conservation action. © 2012 Elsevier B.V.

Vanhanen L.P.,Lincoln University at Christchurch | Emmertz A.,Swedish University of Agricultural Sciences | Savage G.P.,Lincoln University at Christchurch
Food Chemistry | Year: 2011

The levels of 18 different minerals in ten locally produced mono-floral honeys (clover, honeydew, kmahi, mnuka, nodding thistle, rt, rewarewa, twari, thyme and viper's bugloss honey) were determined, as well as moisture content, pH, conductivity and colour. The most abundant minerals were potassium, phosphorus and calcium, ranging between 34.8-3640, 29.5-255 and 7.21-94.3 mg/kg, respectively. Potassium made up 73% of the total mineral content. There was a large range of mean total mineral contents, with honeydew honey having the highest level (4060 mg/kg) and viper's bugloss honey the lowest (126 mg/kg). Honeydew had more than twice the mean total mineral contents than kmahi, the next highest. The heavy metal contents (Cd, Pb and Zn) of the mono-floral honey types investigated were very low. A strong positive relationship between mean conductivity and total mineral content (r2 = 0.973), and pH and total mineral content (r2 = 0.776) was observed in this study. © 2011 Elsevier Ltd. All rights reserved.

Ode A.,Swedish University of Agricultural Sciences | Miller D.,Macaulay Institute
Environment and Planning B: Planning and Design | Year: 2011

With the adoption of the European Landscape Convention the importance of landscape character and amenity functions have gained increased political recognition across Europe. Land-scape complexity has been proposed as an important concept for describing visual character, with a range of landscape metrics developed for describing visual complexity. We present the results of a survey relating specific landscape metrics of complexity with preference for landscape. The survey used visualisations of six scenarios of landscape composition which showed differences in the amount of land cover as well as the distribution between open land use and forest. Metrics of complexity were applied for both map representation and panoramic scenes of the landscape. The relationship between complexity and preference was tested and strong relationships were found for the Shannon diversity index, Shannon evenness index, and aggregation index when applied to both maps and perspective views. The only background factor demonstrating a relationship with preference was age, whilst gender, occupation (ie working with landscape issues or not), and membership of an organization involved with landscape issues all showed weaker relationships with preference. © 2011 Pion Ltd and its Licensors.

Berge A.C.,Ghent University | Wierup M.,Swedish University of Agricultural Sciences
Animal | Year: 2012

Nutritional strategies to minimize Salmonella in food animal production are one of the key components in producing safer food. The current European approach is to use a farm-to-fork strategy, where each sector must implement measures to minimize and reduce Salmonella contamination. In the pre-harvest phase, this means that all available tools need to be used such as implementation of biosecurity measures, control of Salmonella infections in animals at the farm as well as in transport and trade, optimal housing and management including cleaning, disinfection procedures as well as efforts to achieve Salmonella-free feed production. This paper describes some nutritional strategies that could be used in farm control programmes in the major mono-gastric food production animals: poultry and pigs. Initially, it is important to prevent the introduction of Salmonella onto the farm through Salmonella-contaminated feed and this risk is reduced through heat treatment and the use of organic acids and their salts and formaldehyde. Microbiological sampling and monitoring for Salmonella in the feed mills is required to minimize the introduction of Salmonella via feed onto the farm. In addition, feed withdrawal may create a stressful situation in animals, resulting in an increase in Salmonella shedding. Physical feed characteristics such as coarse-ground meal to pigs can delay gastric emptying, thereby increasing the acidity of the gut and thus reducing the possible prevalence of Salmonella. Coarse-ground grains and access to litter have also been shown to decrease Salmonella shedding in poultry. The feed can also modify the gastro-intestinal tract microflora and influence the immune system, which can minimize Salmonella colonization and shedding. Feed additives, such as organic acids, short- and medium-chain fatty acids, probiotics, including competitive exclusion cultures, prebiotics and certain specific carbohydrates, such as mannan-based compounds, egg proteins, essential oils and bacteriophages, have the potential to reduce Salmonella levels when added to the feed. These nutritional strategies could be evaluated and used in farm control programmes. © 2011 The Animal Consortium.

Magnusson U.,Swedish University of Agricultural Sciences | Ljungvall K.,Swedish Medical Products Agency
Reproductive Toxicology | Year: 2014

The scientific literature on altered onset of puberty predominantly involves studies on females. This paper reviews current knowledge on the role of environmental pollutants in dysregulation of male puberty in humans, laboratory rodents and farm animals. The methods used to determine the onset of puberty are well developed in humans and farm animals, and standardized across studies in humans. In laboratory rodents standardized external morphological endpoints are used. There is an increasing weight of evidence from epidemiological studies in humans, as well as from experiments in animals, indicating that environmental pollutants dysregulate puberty in males. Most data are from studies on "classical" persistent environmental pollutants. Assessing the effect of multichemical environmental pollution on dysregulation of puberty in humans is more challenging; further solid epidemiological data would likely contribute most to our understanding, especially if combined with systematically collected field-data from selected wildlife. © 2014 The Authors.

Rising A.,Swedish University of Agricultural Sciences | Johansson J.,Center for Alzheimer Research
Nature Chemical Biology | Year: 2015

Spider silk is strong and extensible but still biodegradable and well tolerated when implanted, making it the ultimate biomaterial. Shortcomings that arise in replicating spider silk are due to the use of recombinant spider silk proteins (spidroins) that lack native domains, the use of denaturing conditions under purification and spinning and the fact that the understanding of how spiders control silk formation is incomplete. Recent progress has unraveled the molecular mechanisms of the spidroin N- and C-terminal nonrepetitive domains (NTs and CTs) and revealed the pH and ion gradients in spiders' silk glands, clarifying how spidroin solubility is maintained and how silk is formed in a fraction of a second. Protons and CO2, generated by carbonic anhydrase, affect the stability and structures of the NT and CT in different ways. These insights should allow the design of conditions and devices for the spinning of recombinant spidroins into native-like silk. © 2015 Nature America, Inc. All rights reserved.

Savage G.P.,Lincoln University at Christchurch | Martensson L.,Swedish University of Agricultural Sciences
Journal of Food Composition and Analysis | Year: 2010

Total, soluble, gastric soluble and intestinal soluble oxalates were determined using three groups of foods. The total and soluble oxalate contents were extracted using hot acid (80 °C, 0.2 mol/l HCl) and hot water (80 °C). Gastric soluble and intestinal soluble oxalates were extracted using an in vitro method; the food samples were incubated for 2 h at 37 °C in gastric and intestinal juice. The extracted oxalates obtained from both methods were then determined by HPLC chromatography. The oxalate contents of taro leaves were determined in the raw leaves and after being baked at 150 °C for 1.5 h either alone or with additions of cows' milk or coconut milk prior to baking. The oxalate contents of four different cultivars of taro corms were determined in the raw corms and after the corms had been either boiled or baked. The oxalate contents of a selection of green leafy Indian vegetables were also determined in the dried raw material. Overall, the total oxalate contents of the foods analysed in this study ranged from 209 mg oxalate/100 g dry matter (DM) for raw Indian radish leaves to 12,576 mg oxalate/100 g DM for raw Indian spinach leaves, while the soluble oxalate contents of the samples ranged from 143 mg soluble oxalate for raw taro corms to 11,900 mg soluble oxalate/100 g DM for raw Indian spinach leaves. Regression analysis of all the gastric soluble oxalate values against the total oxalate values showed that there was a good fit (R2 = 0.955). However, the gastric soluble oxalate values were, on average, 14.2 ± 3.7% lower than those for total oxalate obtained by hot acid extraction. Regression analysis of all the intestinal soluble oxalate contents against the soluble oxalate values showed a good fit between the values (R2 = 0.967). Overall, the intestinal soluble oxalate values were 10.0 ± 6.6% lower than those for soluble oxalate obtained by hot water extraction. © 2009 Elsevier Inc. All rights reserved.

Ragnarsson S.,Holar University College | Lindberg J.E.,Swedish University of Agricultural Sciences
Livestock Science | Year: 2010

The influence of cutting time of mixed grass haylages on energy and nitrogen (N) metabolism, and the coefficients of total tract apparent digestibility (CTTAD) were studied in four mature Icelandic geldings by performing total collection of faeces and urine. The experiment was arranged as 4 × 4 balanced Latin square. The four haylages used were harvested at different times and were considered to be representative in botanical composition for mixed grass haylages in Iceland. The CTTAD of dry matter (DM), organic matter (OM), crude protein, neutral detergent fibre, acid detergent fibre (ADF) and energy were different (p < 0.05) in the haylage batches. The CTTAD of all dietary components and energy decreased with time of cutting. The content of ADF (% in DM) accounted for a major part of the difference in CTTAD of OM (r2 = 0.95) between haylage batches. The urinary nitrogen losses decreased with date of cutting, while the energy losses in urine (as % of digestible energy intake) were unaffected (p > 0.05). The digestible energy content of the haylages studied ranged from 13.4 to 10.8 MJ/kg DM. © 2010 Elsevier B.V. All rights reserved.

Kohler C.,Swedish University of Agricultural Sciences | Wolff P.,Swedish University of Agricultural Sciences | Wolff P.,ETH Zurich | Spillane C.,National University of Ireland
Annual Review of Plant Biology | Year: 2012

Genomic imprinting, the differential expression of an autosomal gene that is dependent on its parent of origin, has independently evolved in flowering plants and mammals. In both of these organism classes, imprinting occurs in embryo-nourishing tissues-the placenta and the endosperm, respectively. It has been proposed that some imprinted genes control nutrient flow from the mother to the offspring. Genome-wide analyses of imprinted genes in plants have revealed that many imprinted genes are located in the vicinity of transposon or repeat sequences, implying that transposon insertions are associated with the evolution of imprinted loci. Imprinted expression of a number of genes is conserved between monocots and dicots, suggesting that long-term selection can maintain imprinted expression at some loci. In terms of epigenetic mechanisms, imprinted expression is largely controlled by an antagonistic action of DNA methylation and Polycomb group-mediated histone methylation in the vicinity of imprinted genes, whereby the position of such epigenetic modifications can determine whether a gene will be expressed mainly from either the maternally or paternally inherited alleles. © 2012 by Annual Reviews. All rights reserved.

Brownfield L.,ETH Zurich | Kohler C.,ETH Zurich | Kohler C.,Swedish University of Agricultural Sciences
Journal of Experimental Botany | Year: 2011

Polyploids, organisms with more than two sets of chromosomes, are widespread in flowering plants, including many important crop species. Increases in ploidy level are believed to arise commonly through the production of gametes that have not had their ploidy level reduced during meiosis. Although there have been cytological descriptions of unreduced gamete formation in a number of plants, until recently none of the underlying genes or molecular mechanisms involved in unreduced gamete production have been described. The recent discovery of several genes in which mutations give rise to a high frequency of unreduced gametes in the model plant Arabidopsis thaliana opens the door to the elucidation of this important event and its manipulation in crop species. Here this recent progress is reviewed and the identified genes and the mechanism by which the loss of protein function leads to the formation of unreduced gametes are discussed. The potential to use the knowledge gained from Arabidopsis mutants to design tools and develop techniques to engineer unreduced gamete production in important crop species for use in plant breeding is also discussed. © 2010 The Author.

Timonen J.,University of Jyväskylä | Gustafsson L.,Swedish University of Agricultural Sciences | Kotiaho J.S.,University of Jyväskylä | Monkkonen M.,University of Jyväskylä
Biological Conservation | Year: 2011

The concept of Woodland Key Habitats (WKH, small-scaled presumed hotspots of biodiversity) has become an essential component of biodiversity conservation in Fennoscandian and Baltic forests. There have been debates over the importance of WKHs in relation to the conservation of biodiversity in production forests. We applied a systematic review protocol and meta-analysis to summarize knowledge on comparisons of biodiversity qualities, such as dead wood and species richness, between WKHs and production forests in relevant countries. We also summarized the knowledge on the impact of edge effects by comparing WKHs surrounded by production forests to WKHs surrounded by clear cuts. Studies had been conducted in Finland, Norway and Sweden. Based on our meta-analysis, WKHs seem to be relative hotspots for dead wood volume, diversity of dead wood, number of species and number of red-listed species. There were some differences also between countries in these biodiversity qualities. Only two studies compared WKHs surrounded by production forests and clear cuts, respectively. Hence, the capability of WKHs to maintain their original species composition and support species persistence over time remains to be addressed, as well as their role in relation to other conservation tools. © 2011 Elsevier Ltd.

Kohler C.,ETH Zurich | Kradolfer D.,Swedish University of Agricultural Sciences
Biochimica et Biophysica Acta - Gene Regulatory Mechanisms | Year: 2011

The sudden rise of angiosperms to ecological dominance was an "abominable mystery" to Charles Darwin, and understanding the underlying evolutionary driving force has remained a scientific challenge since then. The recognition of polyploidization as an important factor for plant speciation is likely to hold a key to this mystery and we will discuss possible mechanisms underlying this phenomenon. Polyploidization raises an immediate reproductive barrier in the endosperm, pointing towards an important but greatly underestimated role of the endosperm in preventing interploidy hybridizations. Parent-of-origin-specific gene expression is largely restricted to the endosperm, providing an explanation for the dosage sensitivity of the endosperm. Here, we review epigenetic mechanisms causing endosperm dosage sensitivity, their possible consequences for raising interploidy and interspecies hybridization barriers and their impact on flowering plant evolution. This article is part of a Special Issue entitled: Epigenetic Control. © 2011 Elsevier B.V.

Forkman J.,Swedish University of Agricultural Sciences | Piepho H.-P.,University of Hohenheim
Biometrics | Year: 2014

The genotype main effects and genotype-by-environment interaction effects (GGE) model and the additive main effects and multiplicative interaction (AMMI) model are two common models for analysis of genotype-by-environment data. These models are frequently used by agronomists, plant breeders, geneticists and statisticians for analysis of multi-environment trials. In such trials, a set of genotypes, for example, crop cultivars, are compared across a range of environments, for example, locations. The GGE and AMMI models use singular value decomposition to partition genotype-by-environment interaction into an ordered sum of multiplicative terms. This article deals with the problem of testing the significance of these multiplicative terms in order to decide how many terms to retain in the final model. We propose parametric bootstrap methods for this problem. Models with fixed main effects, fixed multiplicative terms and random normally distributed errors are considered. Two methods are derived: a full and a simple parametric bootstrap method. These are compared with the alternatives of using approximate F-tests and cross-validation. In a simulation study based on four multi-environment trials, both bootstrap methods performed well with regard to Type I error rate and power. The simple parametric bootstrap method is particularly easy to use, since it only involves repeated sampling of standard normally distributed values. This method is recommended for selecting the number of multiplicative terms in GGE and AMMI models. The proposed methods can also be used for testing components in principal component analysis. © 2014, The International Biometric Society.

Laliberte E.,University of Western Australia | Grace J.B.,U.S. Geological Survey | Huston M.A.,Texas State University | Lambers H.,University of Western Australia | And 3 more authors.
Trends in Ecology and Evolution | Year: 2013

Some of the most species-rich plant communities occur on ancient, strongly weathered soils, whereas those on recently developed soils tend to be less diverse. Mechanisms underlying this well-known pattern, however, remain unresolved. Here, we present a conceptual model describing alternative mechanisms by which pedogenesis (the process of soil formation) might drive plant diversity. We suggest that long-term soil chronosequences offer great, yet largely untapped, potential as 'natural experiments' to determine edaphic controls over plant diversity. Finally, we discuss how our conceptual model can be evaluated quantitatively using structural equation modeling to advance multivariate theories about the determinants of local plant diversity. This should help us to understand broader-scale diversity patterns, such as the latitudinal gradient of plant diversity. © 2013 Elsevier Ltd.

Kradolfer D.,Swedish University of Agricultural Sciences | Kradolfer D.,ETH Zurich | Wolff P.,Swedish University of Agricultural Sciences | Wolff P.,ETH Zurich | And 3 more authors.
Developmental Cell | Year: 2013

Postzygotic reproductive isolation in response to interploidy hybridizations is a well-known phenomenon in plants that forms a major path for sympatric speciation. A main determinant for the failure of interploidy hybridizations is the endosperm, a nutritious tissue supporting embryo growth, similar to the functional role of the placenta in mammals. Although it has been suggested that deregulated imprinted genes underpin dosage sensitivity of the endosperm, the molecular basis for this phenomenon remained unknown. In a genetic screen for suppressors of triploid seed abortion, we have identified the paternally expressed imprinted gene ADMETOS (ADM). Here, we present evidence that increased dosage of ADM causes triploid seed arrest. A large body of theoretical work predicted that deregulated imprinted genes establish the barrier to interploidy hybridization. Our study thus provides evidence strongly supporting this hypothesis and generates the molecular basis for our understanding of postzygotic hybridization barriers in plants. © 2013 Elsevier Inc.

Kradolfer D.,Swedish University of Agricultural Sciences | Kradolfer D.,ETH Zurich | Hennig L.,Swedish University of Agricultural Sciences | Kohler C.,Swedish University of Agricultural Sciences
PLoS Genetics | Year: 2013

Seed development in flowering plants is initiated after a double fertilization event with two sperm cells fertilizing two female gametes, the egg cell and the central cell, leading to the formation of embryo and endosperm, respectively. In most species the endosperm is a polyploid tissue inheriting two maternal genomes and one paternal genome. As a consequence of this particular genomic configuration the endosperm is a dosage sensitive tissue, and changes in the ratio of maternal to paternal contributions strongly impact on endosperm development. The FERTILIZATION INDEPENDENT SEED (FIS) Polycomb Repressive Complex 2 (PRC2) is essential for endosperm development; however, the underlying forces that led to the evolution of the FIS-PRC2 remained unknown. Here, we show that the functional requirement of the FIS-PRC2 can be bypassed by increasing the ratio of maternal to paternal genomes in the endosperm, suggesting that the main functional requirement of the FIS-PRC2 is to balance parental genome contributions and to reduce genetic conflict. We furthermore reveal that the AGAMOUS LIKE (AGL) gene AGL62 acts as a dosage-sensitive seed size regulator and that reduced expression of AGL62 might be responsible for reduced size of seeds with increased maternal genome dosage. © 2013 Kradolfer et al.

Krakowiak J.,Swedish University of Agricultural Sciences | Krakowiak J.,Technical University of Gdansk | Lundberg D.,Swedish University of Agricultural Sciences | Persson I.,Swedish University of Agricultural Sciences
Inorganic Chemistry | Year: 2012

The coordination chemistry of hydrated and solvated vanadium(III), oxovanadium(IV), and dioxovanadium(V) ions in the oxygen-donor solvents water, dimethyl sulfoxide (DMSO), and N,N′-dimethylpropyleneurea (DMPU) has been studied in solution by extended X-ray absorption fine structure (EXAFS) and large-angle X-ray scattering (LAXS) and in the solid state by single-crystal X-ray diffraction and EXAFS. The hydrated vanadium(III) ion has a regular octahedral configuration with a mean V-O bond distance of 1.99 Å. In the hydrated and DMSO-solvated oxovanadium(IV) ions, vanadium binds strongly to an oxo group at ca. 1.6 Å. The solvent molecule trans to the oxo group is very weakly bound, at ca. 2.2 Å, while the remaining four solvent molecules, with a mean V-O bond distance of 2.0 Å, form a plane slightly below the vanadium atom; the mean O = V - Operp bond angle is ca. 98°. In the DMPU-solvated oxovanadium(IV) ion, the space-demanding properties of the DMPU molecule leave no solvent molecule in the trans position to the oxo group, which reduces the coordination number to 5. The O = V - O bond angle is consequently much larger, 107°, and the mean V = O and V-O bond distances decrease to 1.58 and 1.97 Å, respectively. The hydrated and DMSO-solvated dioxovanadium(V) ions display a very distorted octahedral configuration with the oxo groups in the cis position with a mean V = O bond distance of 1.6 Å and a O = V = O bond angle of ca. 105°. The solvent molecules trans to the oxo groups are weakly bound, at ca. 2.2 Å, while the remaining two have bond distances of 2.02 Å. The experimental studies of the coordination chemistry of hydrated and solvated vanadium(III,IV,V) ions are complemented by summarizing previously reported crystal structures to yield a comprehensive description of the coordination chemistry of vanadium with oxygen-donor ligands. © 2012 American Chemical Society.

Gonzalez-Varo J.P.,CSIC - Doñana Biological Station | Lopez-Bao J.V.,Swedish University of Agricultural Sciences | Guitian J.,University of Santiago de Compostela
Journal of Animal Ecology | Year: 2013

Summary: Knowledge of the spatial scale of the dispersal service provided by important seed dispersers (i.e. common and/or keystone species) is essential to our understanding of their role on plant ecology, ecosystem functioning and, ultimately, biodiversity conservation. Carnivores are the main mammalian frugivores and seed dispersers in temperate climate regions. However, information on the seed dispersal distances they generate is still very limited. We focused on two common temperate carnivores differing in body size and spatial ecology - red fox (Vulpes vulpes) and European pine marten (Martes martes) - for evaluating possible functional diversity in their seed dispersal kernels. We measured dispersal distances using colour-coded seed mimics embedded in experimental fruits that were offered to the carnivores in feeding stations (simulating source trees). The exclusive colour code of each simulated tree allowed us to assign the exact origin of seed mimics found later in carnivore faeces. We further designed an explicit sampling strategy aiming to detect the longest dispersal events; as far we know, the most robust sampling scheme followed for tracking carnivore-dispersed seeds. We found a marked functional heterogeneity among both species in their seed dispersal kernels according to their home range size: multimodality and long-distance dispersal in the case of the fox and unimodality and short-distance dispersal in the case of the marten (maximum distances = 2846 and 1233 m, respectively). As a consequence, emergent kernels at the guild level (overall and in two different years) were highly dependent on the relative contribution of each carnivore species. Our results provide the first empirical evidence of functional diversity among seed dispersal kernels generated by carnivorous mammals. Moreover, they illustrate for the first time how seed dispersal kernels strongly depend on the relative contribution of different disperser species, thus on the composition of local disperser assemblages. These findings provide a key starting point for understanding and modelling plant population processes that include mammal-mediated seed dispersal, such as connectivity, range expansion and colonization. © 2012 British Ecological Society.

Steinbach Y.,ETH Zurich | Hennig L.,Swedish University of Agricultural Sciences
Frontiers in Plant Science | Year: 2014

Appropriate timing of flowering is crucial for crop yield and the reproductive success of plants. Flowering can be induced by a number of molecular pathways that respond to internal and external signals such as photoperiod, vernalization or light quality, ambient temperature and biotic as well as abiotic stresses. The key florigenic signal FLOWERING LOCUS T (FT) is regulated by several flowering activators, such as CONSTANS (CO), and repressors, such as FLOWERING LOCUS C (FLC). Chromatin modifications are essential for regulated gene expression, which often involves the well conserved MULTICOPY SUPRESSOR OF IRA 1 (MSI1)-like protein family. MSI1-like proteins are ubiquitous partners of various complexes, such as POLYCOMB REPRESSIVE COMPLEX2 or CHROMATIN ASSEMBLY FACTOR 1. In Arabidopsis, one of the functions of MSI1 is to control the switch to flowering. Arabidopsis MSI1 is needed for the correct expression of the floral integrator gene SUPPRESSOR OF CO 1 (SOC1). Here, we show that the histone-binding protein MSI1 acts in the photoperiod pathway to regulate normal expression of CO in long day (LD) photoperiods. Reduced expression of CO in msi1-mutants leads to failure of FT and SOC1 activation and to delayed flowering. MSI1 is needed for normal sensitivity of Arabidopsis to photoperiod, because msi1-mutants responded less than wild type to an intermittent LD treatment of plants grown in short days. Finally, genetic analysis demonstrated that MSI1 acts upstream of the CO-FT pathway to enable an efficient photoperiodic response and to induce flowering. © 2014 Steinbach and Hennig.

Gonzalez-Varo J.P.,CSIC - Doñana Biological Station | Biesmeijer J.C.,Naturalis Biodiversity Center | Bommarco R.,Swedish University of Agricultural Sciences | Potts S.G.,University of Reading | And 6 more authors.
Trends in Ecology and Evolution | Year: 2013

Pollination is an essential process in the sexual reproduction of seed plants and a key ecosystem service to human welfare. Animal pollinators decline as a consequence of five major global change pressures: climate change, landscape alteration, agricultural intensification, non-native species, and spread of pathogens. These pressures, which differ in their biotic or abiotic nature and their spatiotemporal scales, can interact in nonadditive ways (synergistically or antagonistically), but are rarely considered together in studies of pollinator and/or pollination decline. Management actions aimed at buffering the impacts of a particular pressure could thereby prove ineffective if another pressure is present. Here, we focus on empirical evidence of the combined effects of global change pressures on pollination, highlighting gaps in current knowledge and future research needs. © 2013 Elsevier Ltd.

Weinhofer I.,ETH Zurich | Hehenberger E.,ETH Zurich | Roszak P.,ETH Zurich | Hennig L.,ETH Zurich | And 3 more authors.
PLoS Genetics | Year: 2010

Polycomb group (PcG) proteins act as evolutionary conserved epigenetic mediators of cell identity because they repress transcriptional programs that are not required at particular developmental stages. Each tissue is likely to have a specific epigenetic profile, which acts as a blueprint for its developmental fate. A hallmark for Polycomb Repressive Complex 2 (PRC2) activity is trimethylated lysine 27 on histone H3 (H3K27me3). In plants, there are distinct PRC2 complexes for vegetative and reproductive development, and it was unknown so far whether these complexes have target gene specificity. The FERTILIZATION INDEPENDENT SEED (FIS) PRC2 complex is specifically expressed in the endosperm and is required for its development; loss of FIS function causes endosperm hyperproliferation and seed abortion. The endosperm nourishes the embryo, similar to the physiological function of the placenta in mammals. We established the endosperm H3K27me3 profile and identified specific target genes of the FIS complex with functional roles in endosperm cellularization and chromatin architecture, implicating that distinct PRC2 complexes have a subset of specific target genes. Importantly, our study revealed that selected transposable elements and protein coding genes are specifically targeted by the FIS PcG complex in the endosperm, whereas these elements and genes are densely marked by DNA methylation in vegetative tissues, suggesting that DNA methylation prevents targeting by PcG proteins in vegetative tissues. © 2010 Weinhofer et al.

Lindmark J.,Mälardalen University | Leksell N.,Svensk Vaxtkraft AB | Schnurer A.,Swedish University of Agricultural Sciences | Thorin E.,Mälardalen University
Applied Energy | Year: 2012

Previous studies on substrates for biogas production have shown that different types of pre-treatments make the material more accessible for microbial degradation by breaking down the complex structure of the organic material, thereby increasing their potential for gas production. In this paper, two different mechanical pre-treatment apparatus, i.e. a Grubben deflaker (Gd) and a Krima disperser (Kd), were tested in a full scale setup to evaluate their effects on ley crop silage. The treatments were investigated with regard to their effects on particle size, methane potential, capacity and energy balance. The results after 115. days of incubation in a batch assay show that methane production increased by 59% and 43% respectively after grinding with Gd and Kd. In both treatments, 90% of the ley crop was ground to particles of less than 2. mm and more than 50% of the sample was reduced to particles smaller than 0.125. mm. The energy balance was positive for Gd and around the break-even point for Kd. Analysis of the setup showed that Kd had almost twice the capacity of the Gd. If installed in the co-digestion biogas plant Växtkraft in Västerås, Sweden, the Gd and Kd could increase annual biogas yields by 790. MW. h and 585. MW. h respectively. © 2012 Elsevier Ltd.

Shu H.,ETH Zurich | Wildhaber T.,ETH Zurich | Siretskiy A.,Swedish University of Agricultural Sciences | Gruissem W.,ETH Zurich | And 2 more authors.
Nature Communications | Year: 2012

The accessibility of DNA to regulatory proteins is a major property of the chromatin environment that favours or hinders transcription. Recent studies in flies reported that H3K9me2-marked heterochromatin is accessible while H3K27me3-marked chromatin forms extensive domains of low accessibility. Here we show that plants regulate DNA accessibility differently. H3K9me2-marked heterochromatin is the least accessible in the Arabidopsis thaliana genome, and H3K27me3-marked chromatin also has low accessibility. We see that very long genes without H3K9me2 or H3K27me3 are often inaccessible and generated significantly lower amounts of antisense transcripts than other genes, suggesting that reduced accessibility is associated with reduced recognition of alternative promoters. Low accessibility of H3K9me2-marked heterochromatin and long genes depend on cytosine methylation, explaining why chromatin accessibility differs between plants and flies. Together, we conclude that restriction of DNA accessibility is a local property of chromatin and not necessarily a consequence of microscopically visible compaction. © 2012 Macmillan Publishers Limited.

News Article | October 31, 2016
Site: www.sciencedaily.com

In most European countries there are now permanent, reproducing populations of wolves, lynx and/or brown bears. In some countries, all three. But it is not virgin land that these animals recolonize, but rather lands that are characterized by high human activity. In a review article in the Proceedings of the Royal Society B a European research group highlights gaps in knowledge on the effects of carnivores in human-dominated landscapes. "There is a widespread perception that the return of large predators will save biodiversity," says Joris Cromsigt, Swedish University of Agricultural Sciences (SLU), who is one of the authors. This view is partly based on experiences from Yellowstone National Park. When wolves were reintroduced in this national park, grazing pressure was reduced on the vegetation along the watercourses, which in turn led to a richer flora and fauna. "However, in Europe predators are now returning to landscapes that are strongly modified by humans. Man is part of these ecosystems. Although we are not always physically present, these landscapes are still heavily shaped by us, for example, through forestry and hunting." The ecological impact of large carnivores will most likely be quite different in these anthropogenic landscapes. The review that the authors put together suggests that several of these human actions may mitigate the top-down effects of large carnivores. In other words, humans may remove the claws from the carnivores' paws. Perhaps even more important is that the authors suggest that most of the research done so far on the role that predators play in ecosystems has been carried out in landscapes with very low human impact. "Human activity must be included in research on the ecological effects of large carnivores. This article emphasizes that there are many unexpected ways how humans affect the role of large carnivores in ecosystems," says Cromsigt.

News Article | October 28, 2016
Site: www.sciencedaily.com

Microplastics are increasingly seen as an environmental problem of global proportions. While the focus to date has been on microplastics in the ocean and their effects on marine life, microplastics in soils have largely been overlooked. Researchers are concerned about the lack of knowledge regarding potential consequences of microplastics in agricultural landscapes from application of sewage sludge. Sewage sludge is in principle waste, but it can also represent a resource in agriculture and horticulture. Fertilizer based on sludge contains valuable nutrients, but sustainable use requires that the levels of undesirable substances in the sludge is kept under control. Waste water treatment plants receive large amounts of microplastics emitted from households, industry and surface run-off in urban areas. Most of these microplastics accumulate in the sewage sludge. Today, sludge from municipal sewage treatment plants is applied to agricultural areas as a supplement to traditional fertilizers. These applications are generally well regulated as sludge might contain hazardous substances of different sorts. Microplastics are however not currently on the regulatory agenda for the use of sludge in agriculture. The potential consequences for sustainability and food security have not been adequately analyzed. These concerns have been expressed in an article recently published in the journal Environmental Science & Technology. The researchers behind the article are Luca Nizzetto and Sindre Langaas from the Norwegian Institute for Water Research (NIVA) and Martyn Futter from the Swedish University of Agricultural Sciences (SLU) in Uppsala. "We have found figures from the Nordic countries suggesting that a large fraction of all the microplastics generated in Western societies tend to end up in the sludge in wastewater treatment plants," says Nizzetto. Via the sludge the particles are transferred to agricultural soils. The amount of sewage sludge used as fertilizer varies greatly from country to country. In Europe and North America approximately 50 % of this sludge is reused as fertilizer on average. According to Statistics Norway, about two thirds of the sludge is reused in this manner. Nizzetto et al estimates that between 110,000 and 730,000 tons of microplastics are transferred every year to agricultural soils in Europe and North America, comprehensively. This is more than the estimated total burden of microplastics currently present in ocean water. These figures are of concern since the effects of microplastics accumulating in agricultural soils are unknown. "We have very little knowledge on the effect of microplastics on soil organisms, and their impact on farm productivity and food safety is unknown." The first simulation of microplastic fate on land and rivers In an earlier study from the same authors, and researchers of Oxford University, the first mathematical model describing the dynamics of microplastics' fate in terrestrial environments and rivers was presented. Due to a lack of empirical data on microplastics emissions and concentrations in soils and the stream system, this study was conceived to provide a purely theoretical, nevertheless rigorous, assessment of microplastics circulation. The model is called INCA Microplastics, and simulations have showed a strong influence of meteorological conditions and river characteristics and flows in controlling the export of microplastics from agricultural soils and their transport to the ocean. Application of sewage sludge to soils likely represent a considerable source of microplastics to the coastal and ocean environments. Similar predictions for the transport of microplastics in rivers were independently confirmed by a follow-up study by Besseling et al. INCA Microplastics is an important tool for risk assessment and evaluating sludge management scenarios. It is the first model able to simulate microplastic applications to land, and the consequent fate of these materials in soils and surface waters. The consequences of transfers of microplastics from urban waste water to agricultural soil barely have been considered by researchers and authorities, particularly in lieu of the extended attention directed at microplastics in the ocean. "Clearly further research is needed to get an overview of the problem -- and to find solutions -- so that the growing need in the community for recycling and so-called circular economy can be safeguarded," Luca Nizzetto says.

In a review article in the Proceedings of the Royal Society B a European research group highlights gaps in knowledge on the effects of carnivores in human-dominated landscapes. "There is a widespread perception that the return of large predators will save biodiversity," says Joris Cromsigt, Swedish University of Agricultural Sciences (SLU), who is one of the authors. This view is partly based on experiences from Yellowstone National Park. When wolves were reintroduced in this national park, grazing pressure was reduced on the vegetation along the watercourses, which in turn led to a richer flora and fauna. "However, in Europe predators are now returning to landscapes that are strongly modified by humans. Man is part of these ecosystems. Although we are not always physically present, these landscapes are still heavily shaped by us," for example, through forestry and hunting. The ecological impact of large carnivores will most likely be quite different in these anthropogenic landscapes. The review that the authors put together suggests that several of these human actions may mitigate the top-down effects of large carnivores. In other words, humans may remove the claws from the carnivores' paws. Perhaps even more important is that the authors suggest that most of the research done so far on the role that predators play in ecosystems has been carried out in landscapes with very low human impact. "Human activity must be included in research on the ecological effects of large carnivores. This article emphasizes that there are many unexpected ways how humans affect the role of large carnivores in ecosystems," says Cromsigt. Explore further: Top predators play an important role in human-dominated ecosystems More information: D. P. J. Kuijper et al. Paws without claws? Ecological effects of large carnivores in anthropogenic landscapes, Proceedings of the Royal Society B: Biological Sciences (2016). DOI: 10.1098/rspb.2016.1625

Seidl R.,Swedish University of Agricultural Sciences | Seidl R.,University of Natural Resources and Life Sciences, Vienna | Blennow K.,Swedish University of Agricultural Sciences
PLoS ONE | Year: 2012

Background: In recent decades the frequency and severity of natural disturbances by e.g., strong winds and insect outbreaks has increased considerably in many forest ecosystems around the world. Future climate change is expected to further intensify disturbance regimes, which makes addressing disturbances in ecosystem management a top priority. As a prerequisite a broader understanding of disturbance impacts and ecosystem responses is needed. With regard to the effects of strong winds - the most detrimental disturbance agent in Europe - monitoring and management has focused on structural damage, i.e., tree mortality from uprooting and stem breakage. Effects on the functioning of trees surviving the storm (e.g., their productivity and allocation) have been rarely accounted for to date. Methodology/Principal Findings: Here we show that growth reduction was significant and pervasive in a 6.79·million hectare forest landscape in southern Sweden following the storm Gudrun (January 2005). Wind-related growth reduction in Norway spruce (Picea abies (L.) Karst.) forests surviving the storm exceeded 10% in the worst hit regions, and was closely related to maximum gust wind speed (R 2 = 0.849) and structural wind damage (R 2 = 0.782). At the landscape scale, wind-related growth reduction amounted to 3.0 million m 3 in the three years following Gudrun. It thus exceeds secondary damage from bark beetles after Gudrun as well as the long-term average storm damage from uprooting and stem breakage in Sweden. Conclusions/Significance: We conclude that the impact of strong winds on forest ecosystems is not limited to the immediately visible area of structural damage, and call for a broader consideration of disturbance effects on ecosystem structure and functioning in the context of forest management and climate change mitigation. © 2012 Seidl, Blennow.

Zhang J.,University of Helsinki | Elo A.,University of Helsinki | Helariutta Y.,University of Helsinki | Helariutta Y.,Swedish University of Agricultural Sciences
Current Opinion in Biotechnology | Year: 2011

Wood (secondary xylem) is one of the most important sustainable energy sources for humans. Arabidopsis, despite its herbaceous nature, has become an excellent model to study wood formation. Recent progress has shown that conserved molecular mechanisms may exist in herbaceous plants and trees during vascular development and wood formation. Several transcription factor families and plant hormone species as well as other factors contribute to the regulation of xylem development in both Arabidopsis and woody plants. In this review, we highlight how information gained from the analysis of vascular development in Arabidopsis has improved our understanding of wood formation in trees. © 2010 Elsevier Ltd.

Kroger M.,Swedish University of Agricultural Sciences | Kroger M.,University of Helsinki | Nylund J.-E.,Swedish University of Agricultural Sciences
Forest Policy and Economics | Year: 2012

The large-scale pulp investment model, with its pressure on land, has created conflict and caused major disagreements and open hostility amongst the social movement and NGO networks, state actors, and the pulp and paper companies in Brazil. In this article, Ethical Analysis was applied in the assessment of the dynamics and possibilities of conflict resolution related to the expansion of pulpwood plantations in Brazil's Bahia State, particularly near Veracel Celulose. Ethical Analysis as a tool identifies the complex dynamics of contention through identifying bridges and rifts in the social, ecological and economic viewpoints of the main actors. The analysis was based on field research, interviews, and a review of existing literature. The results indicated that the conflict is marked by politics of power, and as long as this stage continues, the politics of cooperation and conflict resolution would be hard to achieve. The key actors have diverging interests, values and principles, and different ways of presenting their viewpoints. The current investment context is economically and institutionally peripheral and socially weak. Without a radical rethinking and emphasis on ethical and structural reworking of the investment model, the conflict will likely continue to deepen, aggravating investment risk for large-scale business and industrial forestry. © 2010 Elsevier B.V.

Walker L.R.,University of Nevada, Las Vegas | Wardle D.A.,Swedish University of Agricultural Sciences
Trends in Ecology and Evolution | Year: 2014

Ecologists have studied plant succession for over a hundred years, yet our understanding of the nature of this process is incomplete, particularly in relation to its response to new human perturbations and the need to manipulate it during ecological restoration. We demonstrate how plant succession can be understood better when it is placed in the broadest possible temporal context. We further show how plant succession can be central to the development of a framework that integrates a spectrum of ecological processes, which occur over time scales ranging from seconds to millions of years. This novel framework helps us understand the impacts of human perturbations on successional trajectories, ecosystem recovery, and global environmental change. © 2014 Elsevier Ltd.

Smertenko A.,Washington State University | Smertenko A.,Queen's University of Belfast | Bozhkov P.V.,Swedish University of Agricultural Sciences
Journal of Experimental Botany | Year: 2014

Somatic embryogenesis (SE) is a process of differentiation of cells into a plant bypassing the fusion of gametes. As such, it represents a very powerful tool in biotechnology for propagation of species with a long reproductive cycle or low seed set and production of genetically modified plants with improved traits. SE is also a versatile model to study cellular and molecular mechanisms of plant embryo patterning. The morphology and molecular regulation of SE resemble those of zygotic embryogenesis and begin with establishment of apical-basal asymmetry. The apical domain, the embryo proper, proliferates and eventually gives rise to the plantlet, while the basal part, the embryo suspensor, is terminally differentiated and gradually removed via vacuolar programmed cell death (PCD). This PCD is essential for normal development of the apical domain. Emerging evidence demonstrates that signalling events in the apical and basal domains share homologous components. Here we provide an overview of the main pathways controlling the life and death events during SE. © The Author 2014.

Marini L.,University of Padua | Marini L.,Swedish University of Agricultural Sciences | Nascimbene J.,University of Trieste | Nimis P.L.,University of Trieste
Science of the Total Environment | Year: 2011

Lichens are composite organisms consisting of a symbiotic association of a fungus with a photosynthetic partner. Although the photobiont type is a key life-history trait, tests of the potential differential role of the main photobiont types in shaping large-scale patterns of lichen species richness are still absent. The aim of the study was to test the influences of forest structure and climate on epiphytic lichen species richness across Italy and to see whether these relationships change for groups of species sharing different photobiont types. Regional species richness of epiphytic lichens divided into three main photobiont types (i.e. chlorococcoid green algae, cyanobacteria, and Trentepohlia algae) was retrieved for each of the 20 administrative regions. Multiple linear regression was used to quantify the effect of climate and forest structure, and their potential interaction, on the regional species richness for the three photobiont types, accounting also for the effect of regional area. Regional species richness was associated with both climate and forest structure variables but the relationships with both factors were largely photobiont dependent. Regional area and precipitation were the only predictors included in all the models, confirming the strong dependence of lichens on atmospheric water supply, irrespective of the photobiont type. Number of species with chlorococcoid green algae were further positively associated with cover of high forest, whilst lichens with Trentepohlia were further enhanced by warm temperatures. Cyanolichen species richness was only related to area and precipitation. Our study shed light on the relative importance of climate and forest structure on lichen species richness patterns at the macroscale, showing a differential response of the photobiont types to various environmental determinants. This differential response suggested that the current and future impacts of global change on lichens cannot be generalized and that species richness response will be likely dependent on the photobiont type. © 2011 Elsevier B.V.

Hansson K.,Swedish University of Agricultural Sciences | Helmisaari H.-S.,University of Helsinki | Sah S.P.,Finnish Forest Research Institute | Lange H.,Norwegian Forest And Landscape Institute
Forest Ecology and Management | Year: 2013

Fine roots contribute to net primary production in forests, but knowledge of fine root longevity and turnover is still incomplete and limited to few tree species. In this study, we used minirhizotrons to compare fine root biomass, longevity and turnover of Pinus sylvestris L., Betula pendula Roth and Picea abies (L) Karst. in southern Sweden. Minirhizotron tubes were installed in 2006 and root images were taken in 2007-2010. Soil cores were used to estimate fine root biomass. Soil samples were taken from the humus layer and from 0 to 10. cm, 10 to 20. cm and 20 to 30. cm depth in the mineral soil. Only images from the humus layer and the upper 10. cm of mineral soil were included in root analysis. Spruce has a higher aboveground production than pine and birch in southern Sweden and this was reflected in larger fine root biomass as well as higher fine root biomass production. The annual tree fine root biomass production (humus and 0-30cm in mineral soil) was 73, 78 and 284gm-2 in pine, birch and spruce stands, respectively. Thicker fine roots tended to live longer. The majority of the fine roots were thinner than 0.5mm in diameter, with a turnover rate (KM) of 0.4year-1. When comparing all fine roots, i.e. all roots 0-2mm, pine had the highest longevity, 1120days, compared with 900days for spruce and 922days for birch (KM). © 2013 Elsevier B.V.

Allen M.L.,U.S. Department of Agriculture | Walker W.B.,U.S. Department of Agriculture | Walker W.B.,Swedish University of Agricultural Sciences
Journal of Insect Physiology | Year: 2012

The prospects for development of highly specific pesticides based on double stranded ribonucleic acid have been a recent focus of scientific research. Creative applications have been proposed and demonstrated. However, not all insects are sensitive to double stranded RNA (dsRNA) gene knockdown effects; applications in the order Lepidoptera, for example, have met with varied success. Gene knockdown has been demonstrated in several species in the order Hemiptera. In our laboratory, knockdown experiments relied on microinjection of dsRNA into the hemocoel of the tarnished plant bug, Lygus lineolaris. Subsequent experiments delivering dsRNA to insects by feeding were repeatedly unsuccessful in demonstrating knockdown, and a hypothesis was formulated that the dsRNA was digested and degraded by the insect prior to contact with the insect cells. Exposure of dsRNA to insect saliva, insect salivary glands, and insect hemolymph was compared with commercial RNAase III. The saliva of L. lineolaris was found to rapidly digest double stranded RNA. RNAase inhibitor did not affect the activity but heat treatment slowed enzymatic activity. © 2011.

Lamichhaney S.,Uppsala University | Berglund J.,Uppsala University | Almen M.S.,Uppsala University | Maqbool K.,Swedish University of Agricultural Sciences | And 13 more authors.
Nature | Year: 2015

Darwin's finches, inhabiting the Galapagos archipelago and Cocos Island, constitute an iconic model for studies of speciation and adaptive evolution. Here we report the results of whole-genome re-sequencing of 120 individuals representing all of the Darwin's finch species and two close relatives. Phylogenetic analysis reveals important discrepancies with the phenotype-based taxonomy. We find extensive evidence for interspecific gene flow throughout the radiation. Hybridization has given rise to species of mixed ancestry. A 240 kilobase haplotype encompassing the ALX1 gene that encodes a transcription factor affecting craniofacial development is strongly associated with beak shape diversity across Darwin's finch species as well as within the medium ground finch (Geospiza fortis), a species that has undergone rapid evolution of beak shape in response to environmental changes. The ALX1 haplotype has contributed to diversification of beak shapes among the Darwin's finches and, thereby, to an expanded utilization of food resources. © 2015 Macmillan Publishers Limited.

Bommarco R.,Swedish University of Agricultural Sciences | Lindborg R.,University of Stockholm | Marini L.,University of Padua | Ockinger E.,Swedish University of Agricultural Sciences
Diversity and Distributions | Year: 2014

Aim: Species are lost world-wide because of habitat destruction and fragmentation. Impacted communities can exhibit transient dynamics in response to such environmental changes, where slow extinctions and immigration delay the arrival to a new equilibrium. Life history traits such as generation time, resource use and dispersal capacity, as well as landscape history can be expected to affect possible extinction debt, but few have examined this for multiple taxa in the same study and particularly so for arthropods. The aim was to assess under which current and historical land use circumstances an extinction debt occurs for vascular plants and three insect taxa. Location: South-eastern Sweden. Method: We sampled current species richness of habitat specialist and generalist butterflies, bees, hoverflies, and vascular plants in 45 dry to mesic semi-natural grassland fragments of various size and degree of connectivity, and situated in landscapes with contrasting land use conversion history. Habitat loss was estimated in each landscape by comparing modern maps to ~45 year old digitized aerial photographs. An extinction debt can be assumed if historical habitat size and connectivity better explain current species distribution than current habitat variables do. Results: Bees responded rapidly to habitat loss possibly as a result of their primary nesting resource being destroyed. Interestingly, species richness of specialist plants was best explained by historical habitat connectivity, richness of hoverflies by historical habitat area, and richness of butterflies by both historical habitat area and connectivity, indicating extinction debt for these taxa. Habitat generalist butterflies and hoverflies, but not plants and bees, exhibited extinction debt mainly in relation to habitat area. No effect of landscape type was found on the observed extinction debt. Main conclusions: Slow extinctions of persistent and long-lived plants might explain extinction debt for both plants and herbivorous insects linked to these plants. © 2014 John Wiley & Sons Ltd.

Moschou P.N.,Swedish University of Agricultural Sciences | Gutierrez-Beltran E.,Swedish University of Agricultural Sciences | Bozhkov P.V.,Swedish University of Agricultural Sciences | Smertenko A.,Washington State University | Smertenko A.,Queen's University of Belfast
Developmental Cell | Year: 2016

Microtubules play an essential role in breaking cellular symmetry. We have previously shown that separase associates with microtubules and regulates microtubule-dependent establishment of cell polarity in Arabidopsis. However, separase lacks microtubule-binding activity, raising questions about mechanisms underlying this phenomenon. Here we report that the N-terminal non-catalytic domain of separase binds to the C-terminal tail domain of three homologs of the centromeric protein CENP-E Kinesin 7 (Kin7). Conformational changes of Kin7 induced upon binding to separase facilitate recruitment of Kin7/separase complex (KISC) onto microtubules. KISC operates independently of proteolytic activity of separase in promoting microtubule rescue and pauses, as well as in suppressing catastrophes. Genetic complementation experiments in conditional separase mutant rsw4 background demonstrate the importance of KISC for the establishment of cell polarity and for plant development. Our study establishes a mechanism governing microtubule dynamics via the separase-dependent activation of CENP-E-related kinesins. © 2016 Elsevier Inc.

Pawar P.M.-A.,Swedish University of Agricultural Sciences | Koutaniemi S.,University of Helsinki | Tenkanen M.,University of Helsinki | Mellerowicz E.J.,Swedish University of Agricultural Sciences
Frontiers in Plant Science | Year: 2013

Non-cellulosic cell wall polysaccharides constitute approximately one quarter of usable biomass for human exploitation. In contrast to cellulose, these components are usually substituted by O-acetyl groups, which affect their properties and interactions with other polymers, thus affecting their solubility and extractability. However, details of these interactions are still largely obscure. Moreover, polysaccharide hydrolysis to constituent monosaccharides is hampered by the presence of O-acetyl groups, necessitating either enzymatic (esterase or chemical de-acetylation, increasing the costs and chemical consumption. Reduction of polysaccharide acetyl content in planta is a way to modify lignocellulose toward improved saccharification. In this review we: (1 summarize literature on lignocellulose acetylation in different tree species, (2 present data and current hypotheses concerning the role of O-acetylation in determining woody lignocellulose properties, (3 describe plant proteins involved in lignocellulose O-acetylation, (4 give examples of microbial enzymes capable to de-acetylate lignocellulose, and (5 discuss prospects for exploiting these enzymes in planta to modify xylan acetylation. © 2013 Pawar, Koutaniemi, Tenkanen and Mellerowicz.

Hobbie E.A.,University of New Hampshire | Hogberg P.,Swedish University of Agricultural Sciences
New Phytologist | Year: 2012

Contents: Summary 367 I. Introduction 367 II. Background on isotopes 368 III. Patterns of soil δ15N 370 IV. Patterns of fungal δ15N 372 V. Biochemical basis for the influence of fungi on δ15N patterns in plant-soil systems 373 VI. Patterns of δ15N in plant and fungal culture studies 374 VII. Mycoheterotrophic and parasitic plants 375 VIII. Patterns of foliar δ15N in autotrophic plants 376 IX. Controls over plant δ15N 377 X. Conclusions and research needs 378 Acknowledgements 379 References 379 Summary: In this review, we synthesize field and culture studies of the 15N/14N (expressed as δ15N) of autotrophic plants, mycoheterotrophic plants, parasitic plants, soil, and mycorrhizal fungi to assess the major controls of isotopic patterns. One major control for plants and fungi is the partitioning of nitrogen (N) into either 15N-depleted chitin, ammonia, or transfer compounds or 15N-enriched proteinaceous N. For example, parasitic plants and autotrophic hosts are similar in δ15N (with no partitioning between chitin and protein), mycoheterotrophic plants are higher in δ15N than their fungal hosts, presumably with preferential assimilation of fungal protein, and autotrophic, mycorrhizal plants are lower in 15N than their fungal symbionts, with saprotrophic fungi intermediate, because mycorrhizal fungi transfer 15N-depleted ammonia or amino acids to plants. Similarly, nodules of N2-fixing bacteria transferring ammonia are often higher in δ15N than their plant hosts. N losses via denitrification greatly influence bulk soil δ15N, whereas δ15N patterns within soil profiles are influenced both by vertical patterns of N losses and by N transfers within the soil-plant system. Climate correlates poorly with soil δ15N; climate may primarily influence δ15N patterns in soils and plants by determining the primary loss mechanisms and which types of mycorrhizal fungi and associated vegetation dominate across climatic gradients. © 2012 New Phytologist Trust.

Bates P.D.,Washington State University | Fatihi A.,Montana State University | Snapp A.R.,Montana State University | Carlsson A.S.,Swedish University of Agricultural Sciences | And 2 more authors.
Plant Physiology | Year: 2012

Triacylglycerols (TAG) in seeds of Arabidopsis (Arabidopsis thaliana) and many plant species contain large amounts of polyunsaturated fatty acids (PUFA). These PUFA are synthesized on the membrane lipid phosphatidylcholine (PC). However, the exact mechanisms of how fatty acids enter PC and how they are removed from PC after being modified to participate in the TAG assembly are unclear, nor are the identities of the key enzymes/genes that control these fluxes known. By reverse genetics and metabolic labeling experiments, we demonstrate that two genes encoding the lysophosphatidylcholine acyltransferases LPCAT1 and LPCAT2 in Arabidopsis control the previously identified "acyl-editing" process, the main entry of fatty acids into PC. The lpcat1/lpcat2 mutant showed increased contents of very-long-chain fatty acids and decreased PUFA in TAG and the accumulation of small amounts of lysophosphatidylcholine in developing seeds revealed by [14C]acetate-labeling experiments. We also showed that mutations in LPCATs and the PC diacylglycerol cholinephosphotransferase in the reduced oleate desaturation1 (rod1)/lpcat1/lpcat2 mutant resulted in a drastic reduction of PUFA content in seed TAG, accumulating only one-third of the wild-type level. These results indicate that PC acyl editing and phosphocholine headgroup exchange between PC and diacylglycerols control the majority of acyl fluxes through PC to provide PUFA for TAG synthesis. © 2012 American Society of Plant Biologists.

Clemmensen K.E.,Swedish University of Agricultural Sciences | Bahr A.,Lund University | Ovaskainen O.,University of Helsinki | Dahlberg A.,Swedish University of Agricultural Sciences | And 6 more authors.
Science | Year: 2013

Boreal forest soils function as a terrestrial net sink in the global carbon cycle. The prevailing dogma has focused on aboveground plant litter as a principal source of soil organic matter. Using 14C bomb-carbon modeling, we show that 50 to 70% of stored carbon in a chronosequence of boreal forested islands derives from roots and root-associated microorganisms. Fungal biomarkers indicate impaired degradation and preservation of fungal residues in late successional forests. Furthermore, 454 pyrosequencing of molecular barcodes, in conjunction with stable isotope analyses, highlights root-associated fungi as important regulators of ecosystem carbon dynamics. Our results suggest an alternative mechanism for the accumulation of organic matter in boreal forests during succession in the long-term absence of disturbance.

Bates P.D.,Washington State University | Bates P.D.,University of Southern Mississippi | Stymne S.,Swedish University of Agricultural Sciences | Ohlrogge J.,Michigan State University
Current Opinion in Plant Biology | Year: 2013

•Recent research has identified new intricacies in assembly of seed oils.•Oil synthesis involves multiple subcellular compartments requiring lipid trafficking.•Phosphatidylcholine is both a central intermediate and a carrier of acyl chains.•Different plants utilize alternative pathways to produce diverse oil structures.•Major questions and unknowns are highlighted for future oilseed research. Oil produced in plant seeds is utilized as a major source of calories for human nutrition, as feedstocks for non-food uses such as soaps and polymers, and can serve as a high-energy biofuel. The biochemical pathways leading to oil (triacylglycerol) synthesis in seeds involve multiple subcellular organelles, requiring extensive lipid trafficking. Phosphatidylcholine plays a central role in these pathways as a substrate for acyl modifications and likely as a carrier for the trafficking of acyl groups between organelles and membrane subdomains. Although much has been clarified regarding the enzymes and pathways responsible for acyl-group flux, there are still major gaps in our understanding. These include the identity of several key enzymes, how flux between alternative pathways is controlled and the specialized cell biology leading to biogenesis of oil bodies that store up to 80% of carbon in seeds. © 2013 Elsevier Ltd.

Walker L.R.,University of Nevada, Las Vegas | Wardle D.A.,Swedish University of Agricultural Sciences | Bardgett R.D.,Lancaster University | Clarkson B.D.,University of Waikato
Journal of Ecology | Year: 2010

Chronosequences and associated space-for-time substitutions are an important and often necessary tool for studying temporal dynamics of plant communities and soil development across multiple time-scales. However, they are often used inappropriately, leading to false conclusions about ecological patterns and processes, which has prompted recent strong criticism of the approach. Here, we evaluate when chronosequences may or may not be appropriate for studying community and ecosystem development.2. Chronosequences are appropriate to study plant succession at decadal to millennial time-scales when there is evidence that sites of different ages are following the same trajectory. They can also be reliably used to study aspects of soil development that occur between temporally linked sites over time-scales of centuries to millennia, sometimes independently of their application to shorter-term plant and soil biological communities.3. Some characteristics of changing plant and soil biological communities (e.g. species richness, plant cover, vegetation structure, soil organic matter accumulation) are more likely to be related in a predictable and temporally linear manner than are other characteristics (e.g. species composition and abundance) and are therefore more reliably studied using a chronosequence approach.4. Chronosequences are most appropriate for studying communities that are following convergent successional trajectories and have low biodiversity, rapid species turnover and low frequency and severity of disturbance. Chronosequences are least suitable for studying successional trajectories that are divergent, species-rich, highly disturbed or arrested in time because then there are often major difficulties in determining temporal linkages between stages.5. Synthesis. We conclude that, when successional trajectories exceed the life span of investigators and the experimental and observational studies that they perform, temporal change can be successfully explored through the judicious use of chronosequences. © 2010 The Authors. Journal compilation © 2010 British Ecological Society.

Battisti A.,University of Padua | Holm G.,Karolinska University Hospital | Fagrell B.,Karolinska University Hospital | Larsson S.,Swedish University of Agricultural Sciences
Annual Review of Entomology | Year: 2011

The ecological phenomenon of arthropods with defensive hairs is widespread. These urticating hairs can be divided into three categories: true setae, which are detachable hairs in Lepidoptera and in New World tarantula spiders; modified setae, which are stiff hairs in lepidopteran larvae; and spines, which are complex and secretion-filled structures in lepidopteran larvae. This review focuses on the true setae because their high density on a large number of common arthropod species has great implications for human and animal health. Morphology and function, interactions with human tissues, epidemiology, and medical impact, including lammation and allergy in relation to true setae, are addressed. Because data from epidemiological and other clinical studies are ambiguous with regard to frequencies of setae-caused allergic reactions, other mechanisms for setae-mediated disease are suggested. Finally, we briefly discuss current evidence for the adaptive and ecological significance of true setae. © 2011 by Annual Reviews. All rights reserved.

Knight A.L.,U.S. Department of Agriculture | Witzgall P.,Swedish University of Agricultural Sciences
Journal of Chemical Ecology | Year: 2013

The combination of a pathogenic virus and mutualistic yeasts isolated from larvae of codling moth Cydia pomonella is proposed as a novel insect control technique. Apples were treated with codling moth granulovirus (CpGV) and either one of three yeasts, Metschnikowia pulcherrima, Cryptococcus tephrensis, or Aureobasidium pullulans. The combination of yeasts with CpGV significantly increased mortality of neonate codling moth larvae, compared with CpGV alone. The three yeasts were equally efficient in enhancing the activity of CpGV. The addition of brown cane sugar to yeast further increased larval mortality and the protection of fruit against larvae. In comparison, without yeast, the addition of sugar to CpGV did not produce a significant effect. A field trial confirmed that fruit injury and larval survival were significantly reduced when apple trees were sprayed with CpGV, M. pulcherrima, and sugar. We have shown earlier that mutualistic yeasts are an essential part of codling moth larval diet. The finding that yeast also enhances larval ingestion of an insect-pathogenic virus is an opportunity for the development of a novel plant protection technique. We expect the combination of yeasts and insect pathogens to essentially contribute to future insect management. © 2013 Springer Science+Business Media New York (outside the USA).

Kapralov M.V.,University of Oxford | Kubien D.S.,University of New Brunswick | Andersson I.,Swedish University of Agricultural Sciences | Filatov D.A.,University of Oxford
Molecular Biology and Evolution | Year: 2011

Rubisco, the primary photosynthetic carboxylase, evolved 3-4 billion years ago in an anaerobic, high CO 2 atmosphere. The combined effect of low CO 2 and high O 2 levels in the modern atmosphere, and the inability of Rubisco to distinguish completely between CO 2 and O 2, leads to the occurrence of an oxygenation reaction that reduces the efficiency of photosynthesis. Among land plants, C 4 photosynthesis largely solves this problem by facilitating a high CO 2/O 2 ratio at the site of Rubisco that resembles the atmosphere in which the ancestral enzyme evolved. The prediction that such conditions favor Rubiscos with higher kcatCO 2 and lower CO 2/O 2 specificity (SC/O) is well supported, but the structural basis for the differences between C 3 and C 4 Rubiscos is not clear. Flaveria (Asteraceae) includes C 3, C 3-C 4 intermediate, and C 4 species with kinetically distinct Rubiscos, providing a powerful system in which to study the biochemical transition of Rubisco during the evolution from C 3 to C 4 photosynthesis. We analyzed the molecular evolution of chloroplast rbcL and nuclear rbcS genes encoding the large subunit (LSu) and small subunit (SSu) of Rubisco from 15 Flaveria species. We demonstrate positive selection on both subunits, although selection is much stronger on the LSu. In Flaveria, two positively selected LSu amino acid substitutions, M309I and D149A, distinguish C 4 Rubiscos from the ancestral C 3 species and statistically account for much of the kinetic difference between the two groups. However, although Flaveria lacks a characteristic "C 4" SSu, our data suggest that specific residue substitutions in the SSu are correlated with the kinetic properties of Rubisco in this genus. © 2010 The Author.

McBride C.S.,Rockefeller University | McBride C.S.,Howard Hughes Medical Institute | McBride C.S.,Princeton University | Baier F.,Rockefeller University | And 10 more authors.
Nature | Year: 2014

Female mosquitoes are major vectors of human disease and the most dangerous are those that preferentially bite humans. A 'domestic' form of the mosquito Aedes aegypti has evolved to specialize in biting humans and is the main worldwide vector of dengue, yellow fever, and chikungunya viruses. The domestic form coexists with an ancestral, 'forest' form that prefers to bite non-human animals and is found along the coast of Kenya. We collected the two forms, established laboratory colonies, and document striking divergence in preference for human versus non-human animal odour. We further show that the evolution of preference for human odour in domestic mosquitoes is tightly linked to increases in the expression and ligand-sensitivity of the odorant receptor AaegOr4, which we found recognizes a compound present at high levels in human odour. Our results provide a rare example of a gene contributing to behavioural evolution and provide insight into how disease-vectoring mosquitoes came to specialize on humans. © 2014 Macmillan Publishers Limited. All rights reserved.

Lindberg E.,Swedish University of Agricultural Sciences | Hollaus M.,Vienna University of Technology
Remote Sensing | Year: 2012

This study compares methods to estimate stem volume, stem number and basal area from Airborne Laser Scanning (ALS) data for 68 field plots in a hemi-boreal, spruce dominated forest (Lat. 58°N, Long. 13°E). The stem volume was estimated with five different regression models: one model based on height and density metrics from the ALS data derived from the whole field plot, two models based on similar combinations derived from 0.5 m raster cells, and two models based on canopy volumes from the ALS data. The best result was achieved with a model based on height and density metrics derived from 0.5 m raster cells (Root Mean Square Error or RMSE 37.3%) and the worst with a model based on height and density metrics derived from the whole field plot (RMSE 41.9%). The stem number and the basal area were estimated with: (i) area-based regression models using height and density metrics from the ALS data; and (ii) single tree-based information derived from local maxima in a normalized digital surface model (nDSM) mean filtered with different conditions. The estimates from the regression model were more accurate (RMSE 52.7% for stem number and 21.5% for basal area) than those derived from the nDSM (RMSE 63.4%-91.9% and 57.0%-175.5%, respectively). The accuracy of the estimates from the nDSM varied depending on the filter size and the conditions of the applied filter. This suggests that conditional filtering is useful but sensitive to the conditions. © 2012 by the authors.

Wardle D.A.,Swedish University of Agricultural Sciences | Jonsson M.,Umeå University | Bansal S.,Swedish University of Agricultural Sciences | Bansal S.,U.S. Department of Agriculture | And 3 more authors.
Journal of Ecology | Year: 2012

1. Despite recent interest in linkages between above- and below-ground communities and their consequences for ecosystem processes, much remains unknown about their responses to long-term ecosystem change. We synthesize multiple lines of evidence from a long-term 'natural experiment' to illustrate how ecosystem retrogression (the decline in ecosystem process rates due to long-term absence of major disturbance) drives vegetation change, and thus above-ground and below-ground carbon (C) sequestration, and communities of consumer biota. 2. Our study system involves 30 islands in Swedish boreal forest that form a 5000-year, fire-driven retrogressive chronosequence. Here, retrogression leads to lower plant productivity and slower decomposition and a community shift from plants with traits associated with resource acquisition to those linked with resource conservation. 3. We present consistent evidence that above-ground ecosystem C sequestration declines, while below-ground and total C storage increases linearly for at least 5000years following fire absence. This increase is driven primarily by changes in vegetation characteristics, impairment of decomposer organisms and absence of humus combustion. 4. Data from contrasting trophic groups show that during retrogression, biomass or abundance of plants and decomposer biota decreases, while that of above-ground invertebrates and birds increases, due to different organisms accessing resources via distinct energy channels. Meanwhile, diversity measures of vascular plants and above-ground (but not below-ground) consumers respond positively to retrogression. 5. We show that taxonomic richness of plants and above-ground consumers are positively correlated with total ecosystem C storage, suggesting that conserving old-growth forests simultaneously maximizes biodiversity and C sequestration. However, we find little observational or experimental evidence that plant diversity is a major driver of ecosystem C storage on the islands relative to other biotic and abiotic factors. 6. Synthesis. Our study reveals that across contrasting islands differing in exposure to a key extrinsic driver (historical disturbance regime and resulting retrogression), there are coordinated responses of soil fertility, vegetation, consumer communities and ecosystem C sequestration, which all feed back to one another. It also highlights the value of well-replicated natural experiments for tackling questions about above-ground-below-ground linkages over temporal and spatial scales that are otherwise unachievable. © 2012 The Authors. Journal of Ecology © 2012 British Ecological Society.

Khoruts A.,University of Minnesota | Dicksved J.,University of Minnesota | Jansson J.K.,Swedish University of Agricultural Sciences | Sadowsky M.J.,Lawrence Berkeley National Laboratory
Journal of Clinical Gastroenterology | Year: 2010

Clostridium difficile-associated disease (CDAD) is the major known cause of antibiotic-induced diarrhea and colitis, and the disease is thought to result from persistent disruption of commensal gut microbiota. Bacteriotherapy by way of fecal transplantation can be used to treat recurrent CDAD, which is thought to reestablish the normal colonic microflora. However, limitations of conventional microbiologic techniques have, until recently, precluded testing of this idea. In this study, we used terminal-restriction fragment length polymorphism and 16S rRNA gene sequencing approaches to characterize the bacterial composition of the colonic microflora in a patient suffering from recurrent CDAD before and after treatment by fecal transplantation from a healthy donor. Although the patient's residual colonic microbiota, prior to therapy was deficient in members of the bacterial divisions-Firmicutes and Bacteriodetes, transplantation had a dramatic impact on the composition of the patient's gut microbiota. By 14 days posttransplantation, the fecal bacterial composition of the recipient was highly similar to that of the donor and was dominated by Bacteroides spp. strains and an uncharacterized butyrate producing bacterium. The change in bacterial composition was accompanied by resolution of the patient's symptoms. The striking similarity of the recipient's and donor's intestinal microbiota following after bacteriotherapy suggests that the donor's bacteria quickly occupied their requisite niches resulting in restoration of both the structure and function of the microbial communities present. © 2010 by Lippincott Williams & Wilkins.

Drobyshev I.,University of Québec | Drobyshev I.,Swedish University of Agricultural Sciences | Gewehr S.,University of Québec | Berninger F.,University of Helsinki | Bergeron Y.,University of Québec
Journal of Ecology | Year: 2013

To understand how the future climate will affect the boreal forest, we studied growth responses to climate variability in black spruce (Picea mariana [Mill.] B.S.P.) and trembling aspen (Populus tremuloides Michx.), two major co-occurring boreal tree species of the eastern Canadian boreal forest. We analysed climate-growth interaction during (i) periods of non-anomalous growth and (ii) in years with strong growth anomalies. We utilized paired tree-level data for both growth and soil variables, which helped ensure that the studied growth variability was a function of species-specific biology, and not of within stand variation in soil conditions. Redundancy analysis conducted on spruce and aspen tree ring chronologies showed that their growth was affected differently by climate. During non-anomalous years, growth of spruce was favoured by cooler temperatures and wetter conditions, while aspen growth was favoured by higher temperatures and drier conditions. Black spruce and trembling aspen also showed an inverse pattern in respect to expression of growth anomalies (pointer years). A negative growth anomaly in spruce tended to be associated with positive ones in aspen and vice versa. This suggested that spruce and aspen had largely contrasting species-specific responses to both 'average' weather conditions and extreme weather events. Synthesis. Species-specific responses to environmental variability imply that tree responses to future climate will likely be not synchronized among species, which may translate into changes in structure and composition of future forest communities. In particular, we speculate that outcome of climate change in respect to relative abundance of black spruce and trembling aspen at the regional levels will be highly dependent on the balance between increasing temperatures and precipitation. Further, species-specific responses of trees to annual climate variability may enhance the resilience of mixed forests by constraining variability in their annual biomass accumulation, as compared with pure stands, under periods with high frequency of climatically extreme conditions. © 2013 The Authors. Journal of Ecology © 2013 British Ecological Society.

Seidl R.,University of Natural Resources and Life Sciences, Vienna | Rammer W.,University of Natural Resources and Life Sciences, Vienna | Blennow K.,Swedish University of Agricultural Sciences
Environmental Modelling and Software | Year: 2014

Wind is the most detrimental disturbance agent in Europe's forest ecosystems. In recent years, disturbance frequency and severity have been increasing at continental scale, a trend that is expected to continue under future anthropogenic climate change. Disturbance management is thus increasingly important for sustainable stewardship of forests, and requires tools to evaluate the effects of management alternatives and climatic changes on disturbance risk and ecosystem services. We here present a process-based model of wind disturbance impacts on forest ecosystems, integrated into the dynamic landscape simulation model iLand. The model operates at the level of individual trees and simulates wind disturbance events iteratively, i.e., dynamically accounting for changes in forest structure and newly created edges during the course of a storm. Both upwind gap size and local shelter from neighboring trees are considered in this regard, and critical wind speeds for uprooting and stem breakage are distinguished. The simulated disturbance size, pattern, and severity are thus emergent properties of the model. We evaluated the new simulation tool against satellite-derived data on the impact of the storm Gudrun (January 2005) on a 1391ha forest landscape in south central Sweden. Both the overall damage percentage (observation: 21.7%, simulation: 21.4%) as well as the comparison of spatial damage patterns showed good correspondence between observations and predictions (prediction accuracy: 60.4%) if the full satellite-derived structural and spatial heterogeneity of the landscape was taken into account. Neglecting within-stand heterogeneity in forest conditions, i.e., the state-of-the-art in many stand-level risk models, resulted in a considerable underestimation of simulated damage, supporting the notion that tree-level complexity matters for assessing and modeling large-scale disturbances. A sensitivity analysis further showed that changes in wind speed and soil freezing could have potentially large impacts on disturbed area and patch size. The model presented here is available as open source. It can be used to study the effects of different silvicultural systems and future climates on wind risk, as well as to quantify the impacts of wind disturbance on ecosystem services such as carbon sequestration. It thus contributes to improving our capacity to address changing disturbance regimes in ecosystem management. © 2013 Elsevier Ltd.

The disease attacks virtually every part of the tree, from its root collar, stem, to its branches, leaves and seeds. The impact is twofold, both economical and environmental. Ash dieback threatens hundreds of species of lichens, mosses, fungi, birds and plants that depend on the survival of the ash trees. Research suggests the tree species that would eventually replace ash would not be able to preserve the features of the initial ecosystems. FRAXBACK managed to coordinate scattered national initiatives meant to counter the disease. Thanks to their collaboration within the network, researchers published guidelines on sustainable ash tree management for landowners, forest managers, policy makers and researchers working in the field. Network members found ash trees that looked healthy in already devastated areas. This could imply some equally exposed ash could be resistant or tolerant to ash dieback. In response to this, FRAXBACK researchers started listing, GPS mapping and regularly monitoring those specimens across different countries. This way, they could collect genetic material in order to hopefully breed disease-resistant trees. Researchers also recommend focusing on ash clones in seed orchards that have shown a high tolerance to the disease over several years. A team of researchers from the UK, Ireland and Denmark started sequencing the ash tree genome and started sharing their data with FRAXBACK in 2013. Their research received national funding in response to the threat of the fungal disease, first identified in natural woodland across the United Kingdom in 2012. By then, it had already wiped out 90% of the entire ash tree population in Denmark. The team surveyed the entire ash tree DNA variation across Europe and predicted that some British ash trees were more resistant to the fungus than the Danish ones. This was an important step forward in breeding disease tolerant ash trees. Some of the team members are now receiving state funding for the Living Ash Project in order to locate and secure ash trees based on their observed susceptibility to ash dieback and include them in a future breeding programme. One of the highlights of Action FRAXBACK was the conference on guidelines and strategies for countering ash dieback held in late 2014 at the Linnean Society of London. Dr Richard Buggs at Queen Mary University of London, who led the research team sequencing the ash tree DNA, opened the livecast conference, hosting policy makers, researchers and other governmental organisations from various European countries. However, despite the progress, both FRAXBACK leader Dr Rimvydas Vasaitis at the Swedish University of Agricultural Sciences and Dr Richard Buggs - also participating in the network - stressed their concern about the seriousness of the epidemic. They explain that even with modern genetic techniques, it will take many years to breed ash trees with no susceptibility to the fungus. The battle has only just started. Research has also shown Danish ash trees that show more resistance to the fungus, seem to produce fewer chemicals protecting them against insects, such as the alien species emerald ash borer - a beetle that can kill ash forests a lot faster than the ash dieback disease. The challenge now is to identify pathways to breed trees with genes for resistance to both the insect and the ash dieback.

Gygax L.,ART Agroscope Reckenholz Tänikon | Reefmann N.,Swedish University of Agricultural Sciences | Wolf M.,University of Zürich | Langbein J.,Leibniz Institute for Farm Animal Biology
Behavioural Brain Research | Year: 2013

Recent concepts relating to animal welfare accept that animals experience affective states. These are notoriously difficult to measure in non-verbal species, but it is generally agreed that emotional reactions consist of well-coordinated reactions in behaviour, autonomic and brain activation. The aim of the study was to evaluate whether each or a combination of these aspects can differentiate between situations presumed to differ in emotional content. To this end, we repeatedly confronted dwarf goats at short intervals with a covered and an uncovered feed bowl (i.e. presumably frustrating and rewarding situations respectively) whilst simultaneously observing their behaviour, measuring heart-rate and heart-rate variability and haemodynamic changes in the prefrontal cortex using functional near-infrared spectroscopy. When faced with a covered feed bowl, goats occupied themselves at locations away from the bowl and showed increased locomotion, while there was a general increase in prefrontal cortical activity. There was little indication of autonomic changes. In contrast, when feed was accessible, the goats reduced locomotion, focused their behaviour on the feed bowl, showed signs of sympathetically mediated arousal reflecting anticipation and, if any cortical activity at all was present, it was concentrated to the left hemisphere. We thus observed patterns in behaviour, sympathetic reaction and brain activity that distinguished between a situation of frustration and one of reward in dwarf goats. These patterns consisted of a well-coordinated set of reactions appropriate in respect of the emotional content of the stimuli used. © 2012 Elsevier B.V..

Dimitriou I.,Swedish University of Agricultural Sciences | Rosenqvist H.,Swedish University of Agricultural Sciences | Berndes G.,Div. of Physical Resource Theory
Biomass and Bioenergy | Year: 2011

About 16 000 ha of commercial willow Short Rotation Coppice (SRC) fields for production of biomass for energy were planted in the early 1990s in Sweden. The cultivated with SRC area has remained almost stable and was slightly decreased during the last years despite the incentives and predictions for drastic increases. Similar incentives and predictions in other countries have been lately launched. The bioenergy produced in the planted SRC areas in Sweden has been lower than anticipated, partly due to the lower than expected biomass yields and the termination of some willow SRC plantations. Explanations for the low yields are depicted based on analyzing the results of a survey where 175 willow SRC growers participated. Lower biomass yields are attributed to: (i) the low input in management activities; (ii) the choice of land for the willow SRC plantation; (iii) and the level of personal involvement of the farmer. Understanding the reasons to earlier years' performance of willow SRC is important for development of better performing systems in the future, in Sweden as well as in other countries. © 2011 Elsevier Ltd.

Zhu F.,University of Hong Kong | Corke H.,University of Hong Kong | Bertoft E.,Swedish University of Agricultural Sciences
Carbohydrate Polymers | Year: 2011

Unit chain length distributions of amylopectins and their φ,β-limit dextrins (reflecting amylopectin internal part) from 11 Chinese sweetpotato genotypes were characterized by high performance anion-exchange chromatography after debranching, and were related to the thermal and pasting properties of granular starches. The weight-based unit chain length profiles of whole amylopectin and their internal parts both had three distinguishable major groups with approximate range of DP 6-36, 37-68, and >69 for amylopectins and DP 3-25, 26-55, and >55 for φ,β-limit dextrins. Among different genotypes, two different patterns of Bfp (fingerprint B-chains, DP 3-7) were observed for φ,β-limit dextrins, whereas Afp (fingerprint A-chains, DP 6-8) for whole amylopectins were consistent. Reconstruction of amylopectins from their φ,β-limit dextrins revealed that B-chains with internal DP > 20 possessed an external chain length corresponding to the average value DP 12.8. Wide genetic variations were recorded among structural parameters, of which several concerning the amylopectin internal part were highly correlated to the thermal and pasting parameters of sweetpotato starches, and suggested that the internal part of amylopectin is critical to the physical behavior of granular starch. © 2010 Elsevier Ltd. All rights reserved.

Ciannelli L.,Oregon State University | Bartolino V.,Swedish University of Agricultural Sciences | Bartolino V.,Gothenburg University | Chan K.-S.,University of Iowa
Proceedings of the Royal Society B: Biological Sciences | Year: 2012

Density-independent and density-dependent variables both affect the spatial distributions of species. However, their effects are often separately addressed using different analytical techniques. We apply a spatially explicit regression framework that incorporates localized, interactive and threshold effects of both density-independent (water temperature) and density-dependent (population abundance) variables, to study the spatial distribution of a well-monitored flatfish population in the eastern Bering Sea. Results indicate that when population biomass was beyond a threshold a further increase in biomass-promoted habitat expansion in a non-additive fashion with water temperature. In contrast, during years of low population size, habitat occupancy was affected positively only by water temperature. These results reveal the spatial signature of intraspecific abundance distribution relationships as well as the non-additive and non-stationary responses of species spatial dynamics. Furthermore, these results underscore the importance of implementing analytical techniques that can simultaneously account for density-dependent and density-independent sources of variability when studying geographical distribution patterns. © 2012 The Royal Society.

Lindo Z.,University of Western Ontario | Nilsson M.-C.,Swedish University of Agricultural Sciences | Gundale M.J.,Swedish University of Agricultural Sciences
Global Change Biology | Year: 2013

Ecosystems in the far north, including arctic and boreal biomes, are a globally significant pool of carbon (C). Global change is proposed to influence both C uptake and release in these ecosystems, thereby potentially affecting whether they act as C sources or sinks. Bryophytes (i.e., mosses) serve a variety of key functions in these systems, including their association with nitrogen (N2)-fixing cyanobacteria, as thermal insulators of the soil, and producers of recalcitrant litter, which have implications for both net primary productivity (NPP) and heterotrophic respiration. While ground-cover bryophytes typically make up a small proportion of the total biomass in northern systems, their combined physical structure and N2-fixing capabilities facilitate a disproportionally large impact on key processes that control ecosystem C and N cycles. As such, the response of bryophyte-cyanobacteria associations to global change may influence whether and how ecosystem C balances are influenced by global change. Here, we review what is known about their occurrence and N2-fixing activity, and how bryophyte systems will respond to several key global change factors. We explore the implications these responses may have in determining how global change influences C balances in high northern latitudes. © 2013 Blackwell Publishing Ltd.

Manzoni S.,Duke University | Taylor P.,University of Colorado at Boulder | Richter A.,University of Vienna | Porporato A.,Duke University | Agren G.I.,Swedish University of Agricultural Sciences
New Phytologist | Year: 2012

Carbon (C) metabolism is at the core of ecosystem function. Decomposers play a critical role in this metabolism as they drive soil C cycle by mineralizing organic matter to CO2. Their growth depends on the carbon-use efficiency (CUE), defined as the ratio of growth over C uptake. By definition, high CUE promotes growth and possibly C stabilization in soils, while low CUE favors respiration. Despite the importance of this variable, flexibility in CUE for terrestrial decomposers is still poorly characterized and is not represented in most biogeochemical models. Here, we synthesize the theoretical and empirical basis of changes in CUE across aquatic and terrestrial ecosystems, highlighting common patterns and hypothesizing changes in CUE under future climates. Both theoretical considerations and empirical evidence from aquatic organisms indicate that CUE decreases as temperature increases and nutrient availability decreases. More limited evidence shows a similar sensitivity of CUE to temperature and nutrient availability in terrestrial decomposers. Increasing CUE with improved nutrient availability might explain observed declines in respiration from fertilized stands, while decreased CUE with increasing temperature and plant C:N ratios might decrease soil C storage. Current biogeochemical models could be improved by accounting for these CUE responses along environmental and stoichiometric gradients. © 2012 The Authors New Phytologist © 2012 New Phytologist Trust.

Mounier E.,CNRS Biochemistry and Plant Molecular Physiology Laboratory | Pervent M.,CNRS Biochemistry and Plant Molecular Physiology Laboratory | Ljung K.,Swedish University of Agricultural Sciences | Gojon A.,CNRS Biochemistry and Plant Molecular Physiology Laboratory | Nacry P.,CNRS Biochemistry and Plant Molecular Physiology Laboratory
Plant, Cell and Environment | Year: 2014

To optimize their nitrogen nutrition, plants are able to direct root growth in nitrate-rich patches. This depends in Arabidopsis on the NRT1.1 nitrate transporter/sensor. NRT1.1 was shown to display on homogenous medium, an auxin transport activity that lowers auxin accumulation in lateral roots and inhibits their growth at low nitrate. Using a split-root system, we explored the hypothesis that preferential lateral root growth in the nitrate-rich side involves the NRT1.1-dependent repression of lateral root growth in the low nitrate side. Data show that NRT1.1 acts locally to modulate both auxin levels and meristematic activity in response to the low nitrate concentration directly experienced by lateral roots leading to a repression of their growth. A stimulatory role of NRT1.1 in the high nitrate side, which does not rely on changes in auxin levels, is also observed. Altogether, our data suggest that NRT1.1 allows preferential root colonization of nitrate-rich patches by both preventing root growth in response to low nitrate, through modulation of auxin traffic, and stimulating root growth in response to high nitrate, through a yet uncharacterized mechanism. In addition, transcriptional regulation of NRT1.1 affects both mechanisms allowing plants to modulate the effect of nitrate on root branching. © 2013 John Wiley & Sons Ltd.

Blicharska M.,Swedish University of Agricultural Sciences | Van Herzele A.,Research Institute for Nature and Forest INBO
Forest Policy and Economics | Year: 2015

This paper addresses the long-standing debate over the conservation and management of the Białowieza Forest in North-eastern Poland, frequently referred to as the last, large, close-to-natural, temperate, lowland forest in Europe. With the present research we aim to document how particular conceptualisations of "forest" shaped the debate and the fate of the Białowieza Forest. Based on our reconstruction and analysis of argumentation, three dominant discourses could be distinguished, each offering different concepts of forest and people-forest relationships: 1. 'managerial' - with foresters presented as stewards of the forest, actively managing it for sustainable outcomes; 2. 'livelihood' - considering the forest as local heritage and underlining its role in fulfilling people's needs; and 3. 'primaeval' - highlighting the forest's intrinsic value and natural processes, being an international concern. The three discourses remained remarkably stable over the past two decades, but their status of institutionalisation evolved, which in turn influenced their hegemony and power. Importantly, our study demonstrates the active role of parties involved in the debate as they used particular concepts (their own, those of others or new ones) for strategic purposes. We conclude that both the achieved hegemony of a discourse and the particular ways by which its concepts are mobilised by actors may play a decisive role in shaping debate and its policy outcomes. We suggest that future research should focus more on the role of actors in strategically using particular forest-related concepts in concrete situations and to what effects. © 2015 Elsevier B.V.

Payne C.M.,University of Kentucky | Knott B.C.,National Renewable Energy Laboratory | Mayes H.B.,Northwestern University | Hansson H.,Swedish University of Agricultural Sciences | And 4 more authors.
Chemical Reviews | Year: 2015

The enzymatic hydrolysis step represents the second portion of biomass depolymerization and is a major cost driver in bioethanol production due to the high cost of enzyme production. Significant efforts have been expended to understand and improve natural paradigms for enzymatic depolymerization of biomass with the aim to decrease the cost of sugar production for fuels and chemicals production. Cellulase enzyme research has been accelerated due to renewed interest in the production of ethanol from lignocellulosic biomass. Third-generation biofuels are now undergoing focused research and development with the goal of cost-effective production of infrastructure-compatible fuels from lignocellulosic biomass including fuels to fulfill demands in the gasoline, diesel, jet fuel, and maritime sectors.

Rising A.,Karolinska Institutet | Rising A.,Swedish University of Agricultural Sciences
Acta Biomaterialia | Year: 2014

Recent biotechnological progress has enabled the production of spider silk proteins, spidroins, in heterologous hosts. Matrices based on recombinant spidroins support stem cell growth and are well tolerated when implanted in living tissue, thus the material is highly attractive for use in regenerative medicine. However, the matrices made are far from natural silk in terms of mechanical properties and are either spontaneously assembled, which results in heterogeneous products, or spun from harsh solvents with the concomitant risk of harmful remnants in the final products. If we could mimic the spider's aqueous silk spinning process we would likely obtain a material that had reproducible and better characteristics and that more easily could be transferred to clinical practice. Herein, the knowledge of the spiders' silk production system and the prerequisites for artificial spinning and assembly of recombinant proteins are reviewed and discussed in a biomedical context. © 2013 Acta Materialia Inc.

von der Ohe P.C.,Helmholtz Center for Environmental Research | Goedkoop W.,Swedish University of Agricultural Sciences
Science of the Total Environment | Year: 2013

Hydromorphological degradation is a well known stressor for running waters, while the effects of elevated levels of pesticides are widely ignored. Hence, distinguishing between the effects of these two stressors is an urgent task for water managers that aim at appropriate remediation measures. We used a large monitoring data set on benthic invertebrates, habitat descriptors, and physico-chemical variables to develop the SPEAR[%]habitat metric that indicates the effects of in-stream habitat degradation. SPEAR[%]habitat correlated significantly with the habitat degradation score (HDS; based on substratum and vegetation coverage), while it did not respond to any physico-chemical variables (r2=0.20). This relationship improved for streams with low modeled pesticide inputs (r2=0.33), and improved even further for a subset of streams dominated by soft-bottom substrata, i.e. for similar stream-types (r2=0.65). These relationships were confirmed for an independent dataset that was not used in the derivation of the HDS (r2=0.57 and r2=0.65, respectively). These findings show that the SPEAR[%]habitat had a high degree of specificity for the effects of habitat degradation. Conversely, neither the commonly used EPT and ASPT metrics, nor the German Fauna Index or SPEAR[%]pesticides showed significant relationships with HDS. These metrics instead correlated significantly with the run-off potential (RP), a proxy of pesticide contamination of streams. Similarly, RP was also the most important explanatory variable for SPEAR[%]pesticides, followed by alkalinity and the number of forested upstream stretches (r2=0.61). The latter are expected to alleviate pesticide effects, as indicated by higher SPEAR[%]pesticides values. These findings show that an integrated analysis of the two stressor-specific SPEAR-metrics in combination with the metrics of general ecological degradation can help water managers to distinguish between the effects of habitat degradation and pesticide stress, two co-occurring stressors in agricultural landscapes. © 2012 Elsevier B.V.

Hofvander P.,Swedish University of Agricultural Sciences | Doan T.T.P.,Swedish University of Agricultural Sciences | Doan T.T.P.,Nong Lam University | Hamberg M.,Karolinska Institutet
FEBS Letters | Year: 2011

The reduction of acyl-CoA or acyl-ACP to fatty alcohol occurs via a fatty aldehyde intermediate. In prokaryotes this reaction is thought to be performed by separate enzymes for each reduction step while in eukaryotes these reactions are performed by a single enzyme without the release of the intermediate fatty aldehyde. However, here we report that a purified fatty acyl reductase from Marinobacter aquaeolei VT8, evolutionarily related to the fatty acyl reductases in eukaryotes, catalysed both reduction steps. Thus, there are at least two pathways existing among prokaryotes for the reduction of activated acyl substrates to fatty alcohol. The Marinobacter fatty acyl reductase studied has a wide substrate range in comparison to what can be found among enzymes so far studied in eukaryotes. © 2011 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

News Article | September 22, 2016
Site: phys.org

To become a sustainable alternative to meat, reared crickets must eat feeds other than the chicken feed that is most commonly used today. Researchers from the Swedish University of Agricultural Sciences now present a study which shows that there are weeds and agricultural by-products that actually work as single ingredients in feeds for crickets. The study was conducted in Cambodia, where many children suffer from malnutrition and where the need for cheap protein is large.

Vilnius, Lithuania, 2017-02-14 08:28 CET (GLOBE NEWSWIRE) -- INVL Asset Management, one of Lithuania’s leading asset management companies, has established the first closed-end umbrella fund intended for informed investors, the INVL Alternative Assets Umbrella Fund, and its subfund, the INVL Baltic Forests Fund I. They began operations on 13 February this year after the Bank of Lithuania approved the fund rules. The period of the INVL Baltic Forests Fund I subfund’s investment activity will be 5 years, while the subfund itself will operate for up to 8 years with the possibility to extend that term for 2 more years. It is planned that the offering of the subfund’s units to informed investors will begin this month. “In broadening the range of alternative investments, we first of all focus on the value created, so in introducing this new fond we’ll be offering a chance to invest in assets which we know well and believe in. We see investments in the Baltic region’s forests as an opportunity to broaden a portfolio with an asset class which stands out for annual natural growth and is characterised by stability and attractive returns with little correlation to global markets,” said Vytautas Plunksnis, the Head of Private Equity Funds at INVL Asset Management. The new INVL Baltic Forests Fund I subfund will invest in forests in the Baltic countries, above all Lithuania, which are suited to forestry activity. The aim is to build up a consolidated parcel of forest land plots, thus increasing their value and the potential income from planned harvestings. The target average annual net return on investments after expected costs for the fund is 8 per cent. “In our assessment, forests in the Baltic countries, especially Lithuania, have big potential. We believe in this investment and are prepared to participate in this market in accord with the principles of sustainable forest management,” said Sigita Bizulienė, the manager of the INVL Baltic Forests Fund I subfund, who has extensive experience in the area of forest and agricultural land management. Sigita Bizulienė holds a master’s degree in forestry from Aleksandras Stulginskis University and has completed the “Euroforester” international master’s programme at the Swedish University of Agricultural Sciences. From 2005 to 2014 she managed a portfolio of agricultural land within the Invalda INVL group, and from 2014 to 2016 she served as forest purchasing manager for an international forest management company. Units of the fund will be available for acquisition by natural and legal persons who meet the established criteria for informed investors. The minimum investment amount for professional and informed investors will be EUR 30,000. During the initial offering, no single investor will be able to acquire fund units for more than EUR 1 million, with a total of EUR 5 million expected to be raised. Later, with successful development of the fund’s activities, its assets under management may reach up to EUR 50 million. INVL Asset Management obtained authorisation to manage investment funds intended for informed investors from the Bank of Lithuania in October 2016. It is part of the Invalda INVL group, whose companies manage pension and mutual funds, alternative investments, private equity assets, individual portfolios and other financial instruments. As of the end of 2016, they had been entrusted with over EUR 500 million of assets by more than 170,000 clients in Lithuania and Latvia and international investors.

News Article | February 14, 2017
Site: globenewswire.com

Vilnius, Lithuania, 2017-02-14 08:24 CET (GLOBE NEWSWIRE) -- INVL Asset Management, one of Lithuania’s leading asset management companies, has established the first closed-end umbrella fund intended for informed investors, the INVL Alternative Assets Umbrella Fund, and its subfund, the INVL Baltic Forests Fund I. They began operations on 13 February this year after the Bank of Lithuania approved the fund rules. The period of the INVL Baltic Forests Fund I subfund’s investment activity will be 5 years, while the subfund itself will operate for up to 8 years with the possibility to extend that term for 2 more years. It is planned that the offering of the subfund’s units to informed investors will begin this month. “In broadening the range of alternative investments, we first of all focus on the value created, so in introducing this new fond we’ll be offering a chance to invest in assets which we know well and believe in. We see investments in the Baltic region’s forests as an opportunity to broaden a portfolio with an asset class which stands out for annual natural growth and is characterised by stability and attractive returns with little correlation to global markets,” said Vytautas Plunksnis, the Head of Private Equity Funds at INVL Asset Management. The new INVL Baltic Forests Fund I subfund will invest in forests in the Baltic countries, above all Lithuania, which are suited to forestry activity. The aim is to build up a consolidated parcel of forest land plots, thus increasing their value and the potential income from planned harvestings. The target average annual net return on investments after expected costs for the fund is 8 per cent. “In our assessment, forests in the Baltic countries, especially Lithuania, have big potential. We believe in this investment and are prepared to participate in this market in accord with the principles of sustainable forest management,” said Sigita Bizulienė, the manager of the INVL Baltic Forests Fund I subfund, who has extensive experience in the area of forest and agricultural land management. Sigita Bizulienė holds a master’s degree in forestry from Aleksandras Stulginskis University and has completed the “Euroforester” international master’s programme at the Swedish University of Agricultural Sciences. From 2005 to 2014 she managed a portfolio of agricultural land within the Invalda INVL group, and from 2014 to 2016 she served as forest purchasing manager for an international forest management company. Units of the fund will be available for acquisition by natural and legal persons who meet the established criteria for informed investors. The minimum investment amount for professional and informed investors will be EUR 30,000. During the initial offering, no single investor will be able to acquire fund units for more than EUR 1 million, with a total of EUR 5 million expected to be raised. Later, with successful development of the fund’s activities, its assets under management may reach up to EUR 50 million. INVL Asset Management obtained authorisation to manage investment funds intended for informed investors from the Bank of Lithuania in October 2016. It is part of the Invalda INVL group, whose companies manage pension and mutual funds, alternative investments, private equity assets, individual portfolios and other financial instruments. As of the end of 2016, they had been entrusted with over EUR 500 million of assets by more than 170,000 clients in Lithuania and Latvia and international investors.

Vilnius, Lithuania, 2017-02-14 08:28 CET (GLOBE NEWSWIRE) -- INVL Asset Management, one of Lithuania’s leading asset management companies, has established the first closed-end umbrella fund intended for informed investors, the INVL Alternative Assets Umbrella Fund, and its subfund, the INVL Baltic Forests Fund I. They began operations on 13 February this year after the Bank of Lithuania approved the fund rules. The period of the INVL Baltic Forests Fund I subfund’s investment activity will be 5 years, while the subfund itself will operate for up to 8 years with the possibility to extend that term for 2 more years. It is planned that the offering of the subfund’s units to informed investors will begin this month. “In broadening the range of alternative investments, we first of all focus on the value created, so in introducing this new fond we’ll be offering a chance to invest in assets which we know well and believe in. We see investments in the Baltic region’s forests as an opportunity to broaden a portfolio with an asset class which stands out for annual natural growth and is characterised by stability and attractive returns with little correlation to global markets,” said Vytautas Plunksnis, the Head of Private Equity Funds at INVL Asset Management. The new INVL Baltic Forests Fund I subfund will invest in forests in the Baltic countries, above all Lithuania, which are suited to forestry activity. The aim is to build up a consolidated parcel of forest land plots, thus increasing their value and the potential income from planned harvestings. The target average annual net return on investments after expected costs for the fund is 8 per cent. “In our assessment, forests in the Baltic countries, especially Lithuania, have big potential. We believe in this investment and are prepared to participate in this market in accord with the principles of sustainable forest management,” said Sigita Bizulienė, the manager of the INVL Baltic Forests Fund I subfund, who has extensive experience in the area of forest and agricultural land management. Sigita Bizulienė holds a master’s degree in forestry from Aleksandras Stulginskis University and has completed the “Euroforester” international master’s programme at the Swedish University of Agricultural Sciences. From 2005 to 2014 she managed a portfolio of agricultural land within the Invalda INVL group, and from 2014 to 2016 she served as forest purchasing manager for an international forest management company. Units of the fund will be available for acquisition by natural and legal persons who meet the established criteria for informed investors. The minimum investment amount for professional and informed investors will be EUR 30,000. During the initial offering, no single investor will be able to acquire fund units for more than EUR 1 million, with a total of EUR 5 million expected to be raised. Later, with successful development of the fund’s activities, its assets under management may reach up to EUR 50 million. INVL Asset Management obtained authorisation to manage investment funds intended for informed investors from the Bank of Lithuania in October 2016. It is part of the Invalda INVL group, whose companies manage pension and mutual funds, alternative investments, private equity assets, individual portfolios and other financial instruments. As of the end of 2016, they had been entrusted with over EUR 500 million of assets by more than 170,000 clients in Lithuania and Latvia and international investors.

News Article | January 12, 2017
Site: www.techtimes.com

Nanotechnology - What You Should Know Graphene - Here's What You Should Know Spider silk is one of the wonder materials of nature. It is strong, light, supple, and biodegradable yet stronger than steel. The slender silk spun by spiders is 30 times thinner than a human hair yet harder than the synthetic fiber used in making the bullet-proof vest, known as Kevlar. Making artificial spider silk has been a failure for many reasons including use of harsh chemicals and resulting fibers not finding any wider use. However, there is good news now. Researchers at the Swedish University of Agricultural Sciences and Karolinska Institutet have reported success in producing kilometer-long spider silk threads for the first time resembling the original spider silk. The results of the experiment have been published in the journal Nature Chemical Biology. The dream of mass production of spider silk remains a chimera. The challenges include the difficulty in farming carnivorous spiders and raising them in bulk. Technically, synthetic production means handling the complexity and size of protein molecules in silk called "spidroins" which are hard to work with. "In general, the larger the protein, the more difficult it can be to produce, and spider silk happens to be a very large protein, often in the range of 3,000 amino acids," noted Daniel Meyer, marketing executive of biotech company Spiber. According to the Swedish researchers, the challenges of artificial spider silk production were compounded by the difficulties in getting silk proteins that are soluble in water along with the absence of sustained sources like bacteria. In spiders, silk remains stored in their glands as an aqueous solution before they get converted into the fiber. The Swedish researchers set their focus on the critical pH gradient existing in the spider's silk gland. The success of researchers came from replicating the natural process into a biomimetic spider silk spinning. The team had Anna Rising, Jan Johansson, and Marlene Andersson from the Swedish University of Agricultural Sciences and Karolinska Institutet. "We designed a process that recapitulates many of the complex molecular mechanisms of native silk spinning. In the future this may allow industrial production of artificial spider silk for biomaterial applications or for the manufacture of advanced textiles," said Anna Rising. The scientists put to use the same pH variation in their artificial spider silk protein sourced from bacteria but made sure the production process was quantifiable. The proteins they used came from E.coli bacteria. Mimicking the spider silk gland, the biomimetic spinning apparatus could spin kilometer-long fibers by lowering the pH of the artificial aqueous spider silk protein. "To our surprise, this artificial protein is as water soluble as the natural spider silk proteins, which means that it is possible to keep the proteins soluble at extreme concentrations," added Rising. "This allowed us for the first time to spin artificial spider silk without using harsh chemicals," said the study's co-author Jan Johansson. "The high amounts of proteins produced in bacteria allow us to spin a kilometer of the biomimetic fibers from just one liter of E.coli culture," he added. The team also highlighted the possible applications of artificial spider silk, such as bio-compatible threads in regenerative medicine; repair of the spinal cord; and growing stem cells to repair damaged hearts. © 2017 Tech Times, All rights reserved. Do not reproduce without permission.

Metcalfe D.B.,Swedish University of Agricultural Sciences | Fisher R.A.,U.S. National Center for Atmospheric Research | Wardle D.A.,Swedish University of Agricultural Sciences
Biogeosciences | Year: 2011

Understanding the impacts of plant community characteristics on soil carbon dioxide efflux (R) is a key prerequisite for accurate prediction of the future carbon (C) balance of terrestrial ecosystems under climate change. However, developing a mechanistic understanding of the determinants of R is complicated by the presence of multiple different sources of respiratory C within soil - such as soil microbes, plant roots and their mycorrhizal symbionts - each with their distinct dynamics and drivers. In this review, we synthesize relevant information from a wide spectrum of sources to evaluate the current state of knowledge about plant community effects on R, examine how this information is incorporated into global climate models, and highlight priorities for future research. Despite often large variation amongst studies and methods, several general trends emerge. Mechanisms whereby plants affect R may be grouped into effects on belowground C allocation, aboveground litter properties and microclimate. Within vegetation types, the amount of C diverted belowground, and hence R, may be controlled mainly by the rate of photosynthetic C uptake, while amongst vegetation types this should be more dependent upon the specific C allocation strategies of the plant life form. We make the case that plant community composition, rather than diversity, is usually the dominant control on R in natural systems. Individual species impacts on R may be largest where the species accounts for most of the biomass in the ecosystem, has very distinct traits to the rest of the community and/or modulates the occurrence of major natural disturbances. We show that climate vegetation models incorporate a number of pathways whereby plants can affect R, but that simplifications regarding allocation schemes and drivers of litter decomposition may limit model accuracy. We also suggest that under a warmer future climate, many plant communities may shift towards dominance by fast growing plants which produce large quantities of nutrient rich litter. Where this community shift occurs, it could drive an increase in R beyond that expected from direct climate impacts on soil microbial activity alone. We identify key gaps in knowledge and recommend them as priorities for future work. These include the patterns of photosynthate partitioning amongst belowground components, ecosystem level effects of individual plant traits, and the importance of trophic interactions and species invasions or extinctions for ecosystem processes. A final, overarching challenge is how to link these observations and drivers across spatio-temporal scales to predict regional or global changes in R over long time periods. A more unified approach to understanding R, which integrates information about plant traits and community dynamics, will be essential for better understanding, simulating and predicting patterns of R across terrestrial ecosystems and its role within the earth-climate system. © Author(s) 2011.

Mayor J.R.,Smithsonian Tropical Research Institute | Mayor J.R.,Swedish University of Agricultural Sciences | Wright S.J.,Smithsonian Tropical Research Institute | Turner B.L.,Smithsonian Tropical Research Institute
Journal of Ecology | Year: 2014

The concentration, stoichiometry and resorption of nitrogen (N) and phosphorus (P) in plant leaves are often used as proxies of the availability of these growth-limiting nutrients, but the responses of these metrics to changes in nutrient availability remain largely untested for tropical forest trees. We evaluated changes in N and P concentrations, N/P ratios and resorption for four common tree species after 13 years of factorial N and P additions in a lowland tropical forest in Panama. Chronic P addition increased foliar P concentrations, decreased P resorption proficiency and decreased N/P ratios in three locally common eudicot tree species (Alseis blackiana, Heisteria concinna, Tetragastris panamensis). The increase in foliar P involved similar proportional increases in organic and inorganic P in two species and a disproportionately large increase in inorganic P in A. blackiana. Nitrogen addition did not alter foliar N concentrations in any species, but did decrease N resorption proficiency in H. concinna. A fourth species, the palm Oenocarpus mapora, demonstrated remarkably static foliar nutrient concentrations, responding only with a marginal decrease in P resorption proficiency under N plus P co-addition. Synthesis. Collectively, these results suggest that adjustment of N/P ratios can be expected in eudicots exposed to elevated P, but foliar N appears to already be at optimal levels in these lowland rain forest tree species. The complexity of species-specific responses to altered nutrient availability highlights the difficulty in predicting future responses of tropical forest trees to a changing world. Collectively, these results suggest that adjustment of N/P ratios can be expected in eudicots exposed to elevated P, but foliar N appears to already be at optimal levels in these lowland rain forest tree species. The complexity of species-specific responses to altered nutrient availability highlights the difficulty in predicting future responses of tropical forest trees to a changing world. © 2013 British Ecological Society.

Axelsson E.,Uppsala University | Ratnakumar A.,Uppsala University | Arendt M.-L.,Uppsala University | Maqbool K.,Uppsala University | And 8 more authors.
Nature | Year: 2013

The domestication of dogs was an important episode in the development of human civilization. The precise timing and location of this event is debated and little is known about the genetic changes that accompanied the transformation of ancient wolves into domestic dogs. Here we conduct whole-genome resequencing of dogs and wolves to identify 3.8 million genetic variants used to identify 36 genomic regions that probably represent targets for selection during dog domestication. Nineteen of these regions contain genes important in brain function, eight of which belong to nervous system development pathways and potentially underlie behavioural changes central to dog domestication. Ten genes with key roles in starch digestion and fat metabolism also show signals of selection. We identify candidate mutations in key genes and provide functional support for an increased starch digestion in dogs relative to wolves. Our results indicate that novel adaptations allowing the early ancestors of modern dogs to thrive on a diet rich in starch, relative to the carnivorous diet of wolves, constituted a crucial step in the early domestication of dogs. © 2013 Macmillan Publishers Limited. All rights reserved.

Jachowski D.S.,Clemson University | Jachowski D.S.,University of KwaZulu - Natal | Singh N.J.,Swedish University of Agricultural Sciences
Conservation Physiology | Year: 2015

Movements are a consequence of an individual's motion and navigational capacity, internal state variables and the influence of external environmental conditions. Although substantial advancements have been made in methods of measuring and quantifying variation in motion capacity, navigational capacity and external environmental parameters in recent decades, the role of internal state in animal migration (and in movement in general) is comparatively little studied. Recent studies of animal movement in the wild illustrate how direct physiological measurements can improve our understanding of the mechanisms underlying movement decisions. In this review, we synthesize and provide examples of how recent technical advances in the physiology-related fields of energetics, nutrition, endocrinology, immunology and ecotoxicology provide opportunities for direct measurements of physiological state in the study of animal movement. We then propose a framework for practitioners to enable better integration of studies of physiological state into animal movement ecology by assessing the mechanistic role played by physiology as both a driver and a modulator of movement. Finally, we highlight the current limitations and research priorities for better integration of direct measurements of animal physiological state into the study of animal movement. © The Author 2015.

Scogings P.F.,University of Zululand | Hjalten J.,Swedish University of Agricultural Sciences | Skarpe C.,Hedmark University College
Oecologia | Year: 2011

Carbon-based secondary metabolites (CBSMs) are assumed to function as defences that contribute to herbivore-avoidance strategies of woody plants. Severe browsing has been reported to reduce concentrations of CBSMs and increase N concentrations in individual plants, causing heavily browsed plants to be characterised by N-rich/C-poor tissues. We hypothesised that concentrations of condensed tannins (CT) and total polyphenols (TP) should decrease, or N increase, in relation to increasing intensity of browsing, rendering severely browsed plants potentially more palatable (increased N:CT) and less N-limited (increased N:P) than lightly browsed ones. We sampled naturally browsed trees (taller than 2 m) of four abundant species in southern Kruger National Park, South Africa. Species-specific relationships between N:CT, CT, TP and P concentrations and increasing browsing intensity were detected, but N and N:P were consistently invariable. We developed a conceptual post-hoc model to explain diverse species-specific CBSM responses on the basis of relative allocation of C to total C-based defence traits (e.g. spines/thorns, tough/evergreen leaves, phenolic compounds). The model suggests that species with low allocation of C to C-based defence traits become C-limited (potentially more palatable) at higher browsing intensity than species with high allocation of C to C-based defences. The model also suggests that when N availability is high, plants become C-limited at higher browsing intensity than when N availability is low. © 2011 Springer-Verlag.

Wallin M.B.,Uppsala University | Lofgren S.,Swedish University of Agricultural Sciences | Erlandsson M.,University of Reading | Bishop K.,Uppsala University | Bishop K.,Swedish University of Agricultural Sciences
Global Biogeochemical Cycles | Year: 2014

Boreal headwater streams have been identified as hot spots for evasion of greenhouse gases (GHGs). This study was the first to systematically determine the concentrations of CO2 and CH4 in hemiboreal headwater streams. The use of a headspace sampling method focusing on GHGs in combination with a statistically representative selection of more than 200 streams across two regions in Sweden was the basis for defining the base flow concentrations of CO2 and CH4. All streams were supersaturated relative to the atmosphere in CO2 and the majority in CH4 for the 82% of streams in which CH4 was detected. The spatial variability in both CO2 and CH4 was high but positively related to total organic carbon, mean annual temperature, and proportion of peatland in the catchment. There were, however, regional differences in the spatial controls, which are something that predictive models need to consider. The data set allowed for comparison between a headspace and an alkalinity-based method for determining CO2. More than 50% of the streams contained no alkalinity which made the alkalinity-based determination of CO2 impossible. In addition, half of the streams with alkalinity had alkalinities low enough (<0.07 meq L-1) to make the CO2 determination very uncertain. The streams with low pH and no alkalinity contained median CO 2 concentrations that were 45% higher than the streams containing alkalinity. Therefore, large-scale generalizations about CO2 in such headwaters will be significantly underestimated if (1) headwaters are underrepresented and (2) the headwaters are sampled but CO2 is calculated from their alkalinity. Key Points 207 statistically selected headwaters were directly sampled for CO2 and CH4 All streams were supersaturated in CO2 and CH4 but with large spatial variation Indirect methods will create bias in large scale data sets of headwater CO2 ©2014. American Geophysical Union. All Rights Reserved.

Nascimbene J.,University of Trieste | Thor G.,Swedish University of Agricultural Sciences | Nimis P.L.,University of Trieste
Forest Ecology and Management | Year: 2013

This review aims at summarizing literature on epiphytic lichens in relation with forest management in temperate deciduous forests of Europe, including suggestions for mitigating the impact of forestry and stimulating further research. The review is focused on environmental factors that directly depend on, or that are known to interact with forest management, such as tree (and forest) age and size, tree species composition, large scale factors (e.g. climate and air pollution), landscape context, and past forest history. The literature demonstrates the sensitiveness of epiphytic lichens to forestry: forest management, and especially the shelterwood system, is a source of threat for many forest-dwelling lichens. Several studies include explicit recommendations for mitigating the effect of forestry. The main ones are: (a) selective cutting should be preferred to the shelterwood system; (b) the negative effect of the shelterwood system could be mitigated by the extension of the rotation period and by the retention of groups of mature trees at the final harvest; (c) the creation of stands with intermediate canopy openness should be promoted; (d) logs and snags should be retained in production forests; (e) large old trees should be maintained in production forests and some of them left until dead and decomposed ("eternity trees"); (f) tree species diversity should be maintained in mixed stands; (g) forest fragmentation around existing species-rich oldgrowth fragments should be maintained, to create a network of set-aside areas; (h) indicator species could be used for a rapid assessment of forest sites worthy of conservation. However, some topics are still scarcely explored, such as the case of (a) coppice forests, (b) the evaluation of the landscape context and forest history, (c) dead wood-dwelling communities and the role of different types of dead wood for lichen conservation, (d) the effects of emerging infectious diseases, and (e) the use of indicator species to assess the conservation importance of forests. Other research approaches, that are still scarcely developed for lichens, may contribute further information for a more comprehensive understanding of the processes that are behind observed patterns of lichen diversity, such in the case of the evaluation of the role of species functional traits in determining the dispersal ability and the response of lichens to environmental factors. © 2013 Elsevier B.V.

Shen X.,Swedish University of Agricultural Sciences | Shen X.,Dalarna University | Alam M.,Dalarna University | Fikse F.,Swedish University of Agricultural Sciences | And 2 more authors.
Genetics | Year: 2013

As the molecular marker density grows, there is a strong need in both genome-wide association studies and genomic selection to fit models with a large number of parameters. Here we present a computationally efficient generalized ridge regression (RR) algorithm for situations in which the number of parameters largely exceeds the number of observations. The computationally demanding parts of the method depend mainly on the number of observations and not the number of parameters. The algorithm was implemented in the R package bigRR based on the previously developed package hglm. Using such an approach, a heteroscedastic effects model (HEM) was also developed, implemented, and tested. The efficiency for different data sizes were evaluated via simulation. The method was tested for a bacteria-hypersensitive trait in a publicly available Arabidopsis data set including 84 inbred lines and 216,130 SNPs. The computation of all the SNP effects required < 10 sec using a single 2.7-GHz core. The advantage in run time makes permutation test feasible for such a whole-genome model, so that a genome-wide significance threshold can be obtained. HEM was found to be more robust than ordinary RR (a.k.a. SNP-best linear unbiased prediction) in terms of QTL mapping, because SNPspecific shrinkage was applied instead of a common shrinkage. The proposed algorithm was also assessed for genomic evaluation and was shown to give better predictions than ordinary RR. © 2013 by the Genetics Society of America.

Shen X.,Uppsala University | Shen X.,Dalarna University | Pettersson M.,Swedish University of Agricultural Sciences | Ronnegard L.,Dalarna University | And 3 more authors.
PLoS Genetics | Year: 2012

The phenotypic effect of a gene is normally described by the mean-difference between alternative genotypes. A gene may, however, also influence the phenotype by causing a difference in variance between genotypes. Here, we reanalyze a publicly available Arabidopsis thaliana dataset [1] and show that genetic variance heterogeneity appears to be as common as normal additive effects on a genomewide scale. The study also develops theory to estimate the contributions of variance differences between genotypes to the phenotypic variance, and this is used to show that individual loci can explain more than 20% of the phenotypic variance. Two well-studied systems, cellular control of molybdenum level by the ion-transporter MOT1 and flowering-time regulation by the FRI-FLC expression network, and a novel association for Leaf serration are used to illustrate the contribution of major individual loci, expression pathways, and gene-by-environment interactions to the genetic variance heterogeneity. © 2012 Shen et al.

Gabrielsson J.,Swedish University of Agricultural Sciences | Weiner D.,Pharsight
Methods in Molecular Biology | Year: 2012

When analyzing pharmacokinetic data, one generally employs either model fitting using nonlinear regression analysis or non-compartmental analysis techniques (NCA). The method one actually employs depends on what is required from the analysis. If the primary requirement is to determine the degree of exposure following administration of a drug (such as AUC), and perhaps the drug's associated pharmacokinetic parameters, such as clearance, elimination half-life, T max, C max, etc., then NCA is generally the preferred methodology to use in that it requires fewer assumptions than model-based approaches. In this chapter we cover NCA methodologies, which utilize application of the trapezoidal rule for measurements of the area under the plasma concentration-time curve. This method, which generally applies to first-order (linear) models (although it is often used to assess if a drug's pharmacokinetics are nonlinear when several dose levels are administered), has few underlying assumptions and can readily be automated. In addition, because sparse data sampling methods are often utilized in toxicokinetic (TK) studies, NCA methodology appropriate for sparse data is also discussed. © 2012 Springer Science+Business Media, LLC.

Ronnegard L.,Dalarna University | Ronnegard L.,Swedish University of Agricultural Sciences | Valdar W.,University of North Carolina at Chapel Hill
BMC Genetics | Year: 2012

: A number of recent works have introduced statistical methods for detecting genetic loci that affect phenotypic variability, which we refer to as variability-controlling quantitative trait loci (vQTL). These are genetic variants whose allelic state predicts how much phenotype values will vary about their expected means. Such loci are of great potential interest in both human and non-human genetic studies, one reason being that a detected vQTL could represent a previously undetected interaction with other genes or environmental factors. The simultaneous publication of these new methods in different journals has in many cases precluded opportunity for comparison. We survey some of these methods, the respective trade-offs they imply, and the connections between them. The methods fall into three main groups: classical non-parametric, fully parametric, and semi-parametric two-stage approximations. Choosing between alternatives involves balancing the need for robustness, flexibility, and speed. For each method, we identify important assumptions and limitations, including those of practical importance, such as their scope for including covariates and random effects. We show in simulations that both parametric methods and their semi-parametric approximations can give elevated false positive rates when they ignore mean-variance relationships intrinsic to the data generation process. We conclude that choice of method depends on the trait distribution, the need to include non-genetic covariates, and the population size and structure, coupled with a critical evaluation of how these fit with the assumptions of the statistical model. © 2012 Rönnegård and Valdar; licensee BioMed Central Ltd.

Orians C.M.,Tufts University | Orians C.M.,Swedish University of Agricultural Sciences | Ward D.,University of KwaZulu - Natal
Annual Review of Entomology | Year: 2010

Exotic plants provide a unique opportunity to explore the evolution of defense allocation in plants. Many studies have focused on whether enemy release leads to a change in defense allocation. Little research has focused on induced defenses and on how resource availability in the nonindigenous range might cause evolutionary shifts in defense trait allocation. We examine (a) the major evolutionary hypotheses predicting defense expression in plants, (b) the hypotheses explaining defense evolution of exotic species, and (c) the importance of geographic variation in ecological interactions to defense evolution (geographic mosaics). In addition, we review the strengths and weaknesses of experimental approaches, present case studies, and suggest areas that deserve further attention. © 2010 by Annual Reviews All rights reserved.

Yokoyama K.,Massachusetts Institute of Technology | Uhlin U.,Swedish University of Agricultural Sciences | Stubbe J.,Massachusetts Institute of Technology
Journal of the American Chemical Society | Year: 2010

E. coli ribonucleotide reductase catalyzes the reduction of nucleoside 5′-diphosphates into 2′-deoxynucleotides and is composed of two subunits: α2 and β2. During turnover, a stable tyrosyl radical (Y*) at Y122-β2 reversibly oxidizes C439 in the active site of α2. This radical propagation step is proposed to occur over 35 Å, to use specific redox-active tyrosines (Y122 and Y356 in β2, Y731 and Y730 in α2), and to involve proton-coupled electron transfer (PCET). 3-Nitrotyrosine (NO 2Y, pKa 7.1) has been incorporated in place of Y 122, Y731, and Y730 to probe how the protein environment perturbs each pKa in the presence of the second subunit, substrate (S), and allosteric effector (E). The activity of each mutant is <4 × 10-3 that of the wild-type (wt) subunit. The [NO 2Y730]-α2 and [NO2Y731]- α2 each exhibit a pKa of 7.8-8.0 with E and E/β2. The pKa of [NO2Y730]-α2 is elevated to 8.2-8.3 in the S/E/β2 complex, whereas no further perturbation is observed for [NO2Y731]-α2. Mutations in pathway residues adjacent to the NO2Y that disrupt H-bonding minimally perturb its pKa. The pKa of NO2Y122-β2 alone or with α2/S/E is >9.6. X-ray crystal structures have been obtained for all [NO2Y]-α2 mutants (2.1-3.1 Å resolution), which show minimal structural perturbation compared to wt-α2. Together with the pKa of the previously reported NO 2Y356-β2 (7.5 in the α2/S/E complex; Yee, C. et al. Biochemistry 2003, 42, 14541-14552), these studies provide a picture of the protein environment of the ground state at each Y in the PCET pathway, and are the starting point for understanding differences in PCET mechanisms at each residue in the pathway. © 2010 American Chemical Society.

Minnihan E.C.,Massachusetts Institute of Technology | Seyedsayamdost M.R.,Massachusetts Institute of Technology | Seyedsayamdost M.R.,Harvard University | Uhlin U.,Swedish University of Agricultural Sciences | Stubbe J.,Massachusetts Institute of Technology
Journal of the American Chemical Society | Year: 2011

Escherichia coli ribonucleotide reductase is an α2β2 complex and catalyzes the conversion of nucleoside 5′-diphosphates (NDPs) to 2′-deoxynucleotides (dNDPs). The reaction is initiated by the transient oxidation of an active-site cysteine (C439) in α2 by a stable diferric tyrosyl radical (Y122•) cofactor in β2. This oxidation occurs by a mechanism of long-range proton-coupled electron transfer (PCET) over 35 Å through a specific pathway of residues: Y 122•→ W48→ Y356 in β2 to Y731→ Y730→ C439 in α2. To study the details of this process, 3-aminotyrosine (NH2Y) has been site-specifically incorporated in place of Y356 of β. The resulting protein, Y356NH2Y-β2, and the previously generated proteins Y731NH2Y-α2 and Y 730NH2Y-α2 (NH2Y-RNRs) are shown to catalyze dNDP production in the presence of the second subunit, substrate (S), and allosteric effector (E) with turnover numbers of 0.2-0.7 s-1. Evidence acquired by three different methods indicates that the catalytic activity is inherent to NH2Y-RNRs and not the result of copurifying wt enzyme. The kinetics of formation of 3-aminotyrosyl radical (NH 2Y•) at position 356, 731, and 730 have been measured with all S/E pairs. In all cases, NH2Y• formation is biphasic (k fast of 9-46 s-1 and kslow of 1.5-5.0 s -1) and kinetically competent to be an intermediate in nucleotide reduction. The slow phase is proposed to report on the conformational gating of NH2Y• formation, while the kcat of ∼0.5 s -1 is proposed to be associated with rate-limiting oxidation by NH2Y• of the subsequent amino acid on the pathway during forward PCET. The X-ray crystal structures of Y730NH2Y-α2 and Y731NH2Y-α2 have been solved and indicate minimal structural changes relative to wt-α2. From the data, a kinetic model for PCET along the radical propagation pathway is proposed. © 2011 American Chemical Society.

Bommarco R.,Swedish University of Agricultural Sciences | Kleijn D.,Wageningen University | Potts S.G.,University of Reading
Trends in Ecology and Evolution | Year: 2013

Rising demands for agricultural products will increase pressure to further intensify crop production, while negative environmental impacts have to be minimized. Ecological intensification entails the environmentally friendly replacement of anthropogenic inputs and/or enhancement of crop productivity, by including regulating and supporting ecosystem services management in agricultural practices. Effective ecological intensification requires an understanding of the relations between land use at different scales and the community composition of ecosystem service-providing organisms above and below ground, and the flow, stability, contribution to yield, and management costs of the multiple services delivered by these organisms. Research efforts and investments are particularly needed to reduce existing yield gaps by integrating context-appropriate bundles of ecosystem services into crop production systems. © 2012 Elsevier Ltd.

Yokoyama K.,Massachusetts Institute of Technology | Uhlin U.,Swedish University of Agricultural Sciences | Stubbe J.,Massachusetts Institute of Technology
Journal of the American Chemical Society | Year: 2010

Escherichia coli ribonucleotide reductase is an α2β2 complex that catalyzes the conversion of nucleotides to deoxynucleotides and requires a diferric-tyrosyl radical (Y•) cofactor to initiate catalysis. The initiation process requires long-range proton-coupled electron transfer (PCET) over 35 Å between the two subunits by a specific pathway (Y 122•→W48→Y356 within β to Y731→Y730→C439 within α). The rate-limiting step in nucleotide reduction is the conformational gating of the PCET process, which masks the chemistry of radical propagation. 3-Nitrotyrosine (NO2Y) has recently been incorporated site-specifically in place of Y122 in β2. The protein as isolated contained a diferric cluster but no nitrotyrosyl radical (NO2Y•) and was inactive. In the present paper we show that incubation of apo-Y122NO 2Y-β2 with Fe2+ and O2 generates a diferric-NO2Y• that has a half-life of 40 s at 25 °C. Sequential mixing experiments, in which the cofactor is assembled to 1.2 NO 2Y•/β2 and then mixed with α2, CDP, and ATP, have been analyzed by stopped-flow absorption spectroscopy, rapid freeze quench EPR spectroscopy, and rapid chemical quench methods. These studies have, for the first time, unmasked the conformational gating. They reveal that the NO 2Y• is reduced to the nitrotyrosinate with biphasic kinetics (283 and 67 s-1), that dCDP is produced at 107 s-1, and that a new Y• is produced at 97 s-1. Studies with pathway mutants suggest that the new Y• is predominantly located at 356 in β2. In consideration of these data and the crystal structure of Y 122NO2Y-β2, a mechanism for PCET uncoupling in NO2Y•-RNR is proposed. © 2010 American Chemical Society.

News Article | February 25, 2017
Site: www.theguardian.com

The story of a kill is told in the snow. On the Finnish island of Porosaari, we find the first paw print. “That’s a male,” says Asko Kettunen, retired border guard, hunter and tracker. How can he be sure? “It’s big.” Five ravens rise from dark pines, croaking in the icy silence; they will scavenge anything caught by the wolves. We wade through knee-deep snow. There’s a spot of vivid blood and a tuft of moose hair, cleanly cut, which Kettunen deduces has been ripped from a living animal. This, he says, is the moment the wolves made contact. First they try to puncture the intestines; if they succeed, the moose may run on, but the damage is done. We find moose tracks, each hoof print far apart: the animal was running. Kettunen points to wolf prints on either side, to where a second and third wolf joined the chase. There are blood spots and more hair and a pine sapling snapped in two. “The moose collided with a tree, so it was not that well,” Kettunen says, with Finnish understatement. There are spots of blood by every moose print now. Finally, up the hill, is the kill zone. A young moose has been reduced to two front legs and a skin detached precisely from the body, intestines that spill like butcher’s sausages and a mound of freshly chewed grass where its stomach once was. Kettunen thinks that five wolves feasted here the previous night. We find faeces and a curved bed of snow where a contented wolf took a postprandial doze. Finland has a wolf problem. Five and a half million humans share the country with an estimated 235 wolves, and that’s too many, say rural Finns, whose livestock and hunting dogs are being killed. Some parents are scared that wolves will attack their children. “Before, wolves were afraid of people,” Kettunen tells me. “Now people are afraid of wolves.” For the past three years, the government has assuaged these fears with a wolf cull. Last winter, 43 wolves were killed in a “management hunt”, while total fatalities numbered 78, including “problem” wolves shot by police and road casualties. This winter, Helsinki authorised another cull, permitting the death of 53 wolves, to include those shot by police and traffic fatalities. The cull is controversial: the wolf is a protected, endangered species. Critics say Finland is in breach of EU law. A candlelit vigil for slaughtered wolves took place in Helsinki last month, and a wolf hunt saboteur group has sprung up on social media. Hunters say they’ve been disrupted by fireworks, vandalised trail-cameras and a hunting shelter burned to the ground. One angry hunter offered a bounty of €50 (£42) to Russian hunters for each wolf they kill, promising to tip them off when they spot a wolf crossing from the Russian border. In this apparently calm and phlegmatic country, the wolf polarises opinion. All across Europe, the wolf is on the rise. Driven to extinction by the middle of the 20th century, it trotted back into France in the 1990s and into Germany in 1998. Wolves are roaming through Denmark, the Netherlands and, late last year, reached the Belgium-Luxembourg border for the first time in 118 years. Europe (excluding Russia, Ukraine and Belarus) now hosts more than 12,000 wolves, twice as many as the United States (excluding Alaska) – despite being half the size and more than twice as densely populated. Recent reports of wolves on the edge of Paris have been treated sceptically by scientists, but they are nevertheless thriving in suburban Germany and other densely populated areas. Inevitably, there has been a human backlash. Last year, Norway announced plans to kill 70% of its wolf population of just 68, to protect sheep flocks, before outrage prompted the authorities to backtrack and propose a cull of just 15 wolves. Two years before that, Tuscan farmers dumped wolf carcasses in town centres in protest at their burgeoning population. French farmers have also demanded that its authorities shoot more wolves. For them, the wolf poses a threat to their way of life; for others, it stirs deep fears still given cultural expression in everything from fairytales to music videos. The animal may be a symbol of freedom and nature’s ability to bounce back, but it also embodies two very contemporary tensions: the gulf between countryside and city, and the chasm between ordinary people and an uncaring political elite. Pia Ikonen’s family life is recognisably 21st century: inside her modest bungalow, her eldest child, Lukas, nine, is transfixed by a tablet; Lotta, eight, and Lucia, six, watch Kung Fu Panda 3 on the telly, while Linda, four, reads a picture book showing a wolf pulling a sledge carrying two happy kittens. But during her 10 years living a mile and a half from the Russian border, Ikonen has seen wolves become ever bolder. Four years ago, her dog, Ninni, was snatched in broad daylight from her garden and killed by a pack. This winter, she has found two sets of wolf tracks in her snowbound yard. Dusk is falling. Would she let her children play on the trampoline outside? “If we have wolves circling, they can’t be outside in the daytime alone, and in the darkness, not at all,” Ikonen says. “It is very much a problem if you can’t let your children run around or walk your dog freely.” The local community pays for an expensive “wolf taxi” to transport her children, and 31 others in the region, from their front doors to school, so they don’t have to wait at remote bus stops. Is Ikonen tempted to move to a safer town? She laughs. “It should be the wolves who don’t stay,” she says. This is a territorial dispute. Wolves were driven to virtual extinction in Finland after a spate of attacks on children at the end of the 19th century. The story of a pair of rogue wolves that killed 35 children over 18 months in the early 1880s is still widely repeated. Are such fears of wolves rational, I ask Ilpo Kojola, research professor at the Finnish government’s National Resources Institute (its acronym is Luke and its newsletter is Leia; Finnish scientists have a sense of humour). “The risk of a wolf attack is really, really tiny nowadays,” he says, explaining that the historic attacks happened in an era when children led cattle into the forests, and when there were no moose for the wolves to eat. Wolves can kill people – a jogger was killed in Alaska in 2010 – but a scientific study in which humans approached wolves 125 times in Scandinavia found no occasions of aggressive behaviour: on 123 occasions, the wolves ran away; on the other two, an alpha female exhibited harmless “defensive” behaviour near her pups. Instead, the hostility towards wolves in rural Finland is mostly because they take hunting dogs. Finland has 300,000 amateur hunters, more than 5% of its population. Helsinki airport is decorated with stuffed hares and wolverine, and much of its rich animal life – beavers, lynx, bears – can be shot under a strict licence system. Moose hunting is particularly popular, a pursuit that has evolved over decades, with GPS collar-wearing dogs chasing moose up to 15km beyond the hunter, who follows it on a screen. “They bark when they stop the moose,” explains Kai Tikkunen of the Finnish Hunters’ Association, and then “it’s like an ice-cream truck calling the wolves.” So the wolf is a rival, killing moose that hunters would like to catch? “The big problem is not that they eat the moose; the big problem is that they kill the dogs. It’s sometimes very scary when I go to the forest: I don’t know if my dog is going to come out alive.” Hunters are compensated for dogs killed by wolves, but it can take 18 months and does not bring back a pedigree animal they may have spent years training. The snowbound track sparkles under my headlights as I drive 18km beyond the nearest shop to meet Ari Määttänen, who lives alone with Minni, his Finnish Spitz. This dainty, bird-hunting dog is on a long leash in his snowy yard, as some dogs are still kept in Finland. “I like the countryside very much,” Määttänen says. “It’s just nature and it’s free. There’s no noise and I can see the stars.” He also enjoys all but one of his dangerous fellow species. “I like the bears, the lynx, the adder,” he says. “If 10 bears are around this house, that’s fine. But one wolf? I do not like it, not at all.” Määttänen’s beloved previous dog, Kessu, was killed on 22 January last year. His description of the loss sounds like the abduction of a child. He saw two wolves 30m from his window in December 2015. “They don’t jog for pleasure,” he says. “They were looking for food. And after that, the wolves knew I had a dog.” The “wolf circle”, whereby a pack of five or more wolves scour their 1,000 sq km territory for food, takes two and a half weeks in Määttänen’s neighbourhood. “They took one circle and the dog was not outside. But on the second circle it was there. It was 12.30pm and I remember Kessu was staring into the forest. He started walking in that direction” – he points to a place where his garden blends into the forest – “and vanished from sight.” Later that afternoon, a neighbour called to warn him that two wolves had crossed the road nearby. “I went out with a gun but it was too late.” He found scuffle marks, then wolf tracks. “They had been waiting 100m away for my dog. They had invited the dog to play and then...” he pauses. “My dog ran into the wolf’s mouth.” There had been no barking. There was no blood. The wolf was so strong it took Kessu without a sound. How does he know the wolf was big? “Because on Sunday the hunters shot it,” he says. Local hunters had quickly obtained a permit to kill this “problem” wolf. Määttänen throws a fluffy object on to the kitchen table. “That’s what’s left of my beautiful dog,” he says. It’s Kessu’s tail. A few days later, hunters found something else in the snow. Määttänen shows me a photo on his phone: Kessu’s head, so neatly severed it looks like a surgical operation. Ari Turunen, a paramedic who lives with his wife and two young children in a wooded village, is the leader of the local hunting group in Ilomantsi. Underneath his snowsuit, a white and grey camouflage for winter hunting, he wears a black T-shirt that says, in English, “99% bear hunter”. According to Turunen, the local wolf population has grown from two packs to seven or eight. “Five years ago, it was rare for normal people to see wolves. It would be written about in a newspaper. Now they see them daily,” he says. “We should never let the wolf population grow this quickly, because it disrupts the balance of nature.” One reason for the wolf’s resurgence is rural depopulation. Outside its cities, Finland does not look prosperous: the mechanisation of forestry has stripped jobs from the countryside and picturesque cottages lie derelict in snowy forests. For those who remain, hunting is a social glue. “We don’t have any ice-skating halls here,” Turunen says. “All my friends and friends’ wives hunt. It’s part of everyday life. I spend a lot of time in nature, fishing, and picking mushrooms and berries with the kids. I’m a nature conservationist.” Five days ago, Turunen and his fellow hunters went after two wolves. One of them had been attracted to lard put out for songbirds. It also encountered a jogger near a village. “It was a very bold one,” Turunen says. He has taken his three-year-old son hunting since he was a baby, but he doesn’t take him wolf-hunting: there’s too much waiting around in the cold. On last week’s hunt, they began at 4am and killed both wolves by midday. The bodies were then dispatched to government scientists for DNA tests; these help to map the wolf population, and confirm the animals are wolves and not wolf-dog hybrids. Hunting a wolf is tightly regulated: only a few permits will be issued for each region, and hunters stand more chance of obtaining one if they identify a “problem” wolf. Wolves can’t be chased on snowmobiles, and no more than 50 people can hunt at a time. Usually, a few hunters on skis will move through the forest with dogs, attempting to flush resting wolves towards a circle of waiting guns. Across the nearby border, the Russian authorities reward hunters for killing some of their 50,000 wolves, which are considered vermin. Turunen says it is illogical to have two such different approaches, when wolves move freely between the countries. “It’s stupid that, on the other side, it’s considered a pest and you get money for killing it, and on this side you go to prison.” His own view is that the wolf should be a “valuable and respected game animal”, a hunting prize. Does the Finnish government understand the concerns of rural people? “No,” Turunen says. “This discussion is dominated by people who have never seen a wolf or lived in a wolf area. The matter should be decided in the areas where it takes place, and not in Helsinki. If I managed street cleaning in Helsinki they would be equally screwed,” he laughs. “And the problem is, some things are not decided in Helsinki but in Brussels, where they understand it even less.” On the train from rural Finland to Helsinki, I chat to a young suburban Finn. He says he can understand both sides of the wolf debate; but when I ask him how many wolves there are in Finland, he guesses at 5,000. I tell him there are barely 200 and he changes his mind. “This animal should be protected,” he declares. Most Finns, says Sami Saynevirta, manager of Luonto-Liitto, a Finnish wildlife charity, have no idea the country has so few wolves. “Finnish people are really surprised when we tell them it’s an endangered species. They don’t realise we have so much poaching.” Saynevirta argues that Finland needs help from the EU, punitive or otherwise, to stop the wolf cull. “This is not good for Finland’s reputation for ecotourism,” he says. “Wolves could be more valuable for Finland alive than hunted.” The Finnish government has calculated that if it maintains a minimum of 25 wolf packs, it won’t be breaking EU law. The first year of its wolf hunt, 2015, was considered a success; but the second, last winter, was not, because eight alpha females were killed – too many. Filmmaker Stefan Gofferje has lodged a criminal complaint against Finnish officials for violating EU law. Gofferje, a German who lives in Finland, tells me he has loved wolves since he was a boy. His pet dog is 55% wolf; he “lives in my apartment, sleeps in my bed, goes for a 30km walk every day and is a local star here in my village. It’s practically impossible to train a wolf. When I ask him to do something, I ask him – I’m not telling him.” Gofferje’s legal complaint is currently undergoing what he calls “client ping-pong”, shuffled between government departments and jurisdictions. He plans further challenges, contrasting the Finns’ apparent willingness to shoot any wolves found near houses with Germany, where “problem” wolves spotted close to human habitation are first tracked with GPS to understand their movements, then deterred – and destroyed only if displaying direct and threatening behaviour towards humans. Germany has invested millions in public education programmes focused on its new wolf population; and only education will help people and wolves coexist, Gofferje argues. “It’s not enough for the government just to make rules or prosecute poachers. They must educate people,” he says. “If your child is afraid of something, do you remove the cause of the fear, or do you educate the child to combat the fear itself?” “We have people standing on both sides of us kicking our ankles. If both our ankles are sore, then we’ve done something right,” says Sami Niemi, the likable official in Finland’s Ministry of Agriculture, who oversees its wolf policy (and doesn’t hunt himself). “This is not an issue where you can find a solution that suits all: we have to find the middle way. That leaves everyone unhappy: there are either too many licences or too many wolves, so we can’t win.” The stated purpose of Finland’s cull is to reduce poaching. When the wolf was completely protected, Niemi explains, “illegal hunting was a big problem for us. If the population grew to 140 or 150, the next year it went back down. It’s not just hunters, it’s local people in general. They put pressure on the hunters to deal with the issue [illegally], so we had to do something.” But conservationists say this argument is equivalent to introducing government burglaries to reduce stealing. The only winner is the government. “With the ministry doing this legal hunt, they get fewer phone calls and emails from angry hunters,” says Mari Nyyssölä-Kiisla, chair of Luonto-Liitto’s wolf action group. “They think this is a good thing: ‘We’ve got more peace. The people are happy.’” In a recent study, ecologists Guillaume Chapron and Adrian Treves analysed wolf population growth rates in Michigan and Wisconsin, and found that government-sanctioned culls in those US states caused a change in wolf population, which they suggested was most likely the result of illegal killing. “Wolf culling may have sent a negative message about the value of wolves or acceptability of poaching,” they concluded. In that sense, culling is a political act, Chapron explains on the phone from the Swedish University of Agricultural Sciences. “The wolf conflict is not strictly about wolves,” he says. “It’s a conflict between people about who controls the land. The wolf is associated with wilderness only in our minds – it is a species that can live everywhere. I’m not saying that wolves do not create damage. But the wolf is like a predatory roe deer, and we don’t associate roe deer with wilderness. Hunters often consider that wild animals are their property to harvest, while environmentalists are more fired up by the wolf than the roe deer. “The wolf asks very disturbing questions,” Chapron continues. “In France, when wolves kill livestock in their national parks, farmers say, ‘We can’t survive with wolves, they are destroying our livestock’. But environmentalists ask in return: ‘Why do we even have sheep in our national parks?’ The farmers will say that it is a tradition. But is subsidised overgrazing a tradition? The debate becomes very heated, because the wolf is questioning economic practices, land use and the allocation of power in the countryside.” Even in consensus-loving countries such as Finland, wolf-haters and wolf-lovers do battle online, trading threats, insults and wild conspiracies about illegal poaching or zoos deliberately releasing wolves. On the border with Russia, fearful locals share pictures of what they claim is a burgeoning population of Russian wolf-dogs. (The research professor Ilpo Kojola tells me that genetic testing of 450 Finnish wolves over 20 years has revealed only three cases of wolf-dog hybrids.) A suspicion of experts, scientists, entrenched power and political elites is a common thread in many of these discussions. Among local people who fear wolves, there is a particular dislike of the EU. Chapron is not making a political point but tells me his research has led him to conclude that EU protection has been key to the wolf’s resurgence, as well as that of other large predators including the brown bear and lynx. “If there wasn’t this strict legislation, there would be very few or no large carnivores in Europe.” Back in snowbound Finland, I ask local hunter Asko Kettunen, who is also a wildlife photographer, if ecotourism (spotting live wolves) could replace hunting. “No,” he replies firmly. “Feeding or photographing the wolves gets them comfortable with people and more problems will come.” Does he hate the wolf? “No. I don’t like that they kill my dogs, but I don’t hate the animal, not at all. It’s so intelligent, it’s so difficult to catch and it adapts to its surroundings so quickly, faster than other species. The wolf belongs in Finnish nature, just not in yards and gardens. Many people say that hunters hate wolves, but we tolerate them and hope they don’t do any damage. It’s not hatred – it’s realism.”

Chapman W.K.,Borland | Paul L.,Swedish University of Agricultural Sciences
Microbial Ecology | Year: 2012

Tuberculate mycorrhizae on Pinus contorta (lodgepole pine) have previously been shown to reduce acetylene, but an outstanding question has been to what degree these structures could meet the nitrogen requirements of the tree. We compared the growth, tissue nitrogen contents, and stable nitrogen isotope ratios of P. contorta growing in gravel pits to the same species growing on adjacent intact soil. Trees growing in severely nitrogen deficient gravel pits had virtually identical growth rates and tissue nitrogen contents to those growing on intact soil that had nitrogen levels typical for the area. δ15N values for trees in the gravel pits were substantially lower than δ15N values for trees on intact soil, and isotope ratios in vegetation were lower than the isotope ratios of the soil. The form of soil nitrogen in the gravel pits was almost exclusively nitrate, while ammonium predominated in the intact soil. Discrimination against 15N during plant uptake of soil nitrate in the highly N-deficient soil should be weak or nonexistent. Therefore, the low δ15N in the gravel pit trees suggests that trees growing in gravel pits were using another nitrogen source in addition to the soil. Precipitation-borne nitrogen in the study area is extremely low. In conjunction with our other work, these findings strongly suggests that P. contorta and its microbial symbionts or associates fix nitrogen in sufficient amounts to sustain vigorous tree growth on the most nitrogen-deficient soils. © 2012 The Author(s).

Peterson M.J.,Texas A&M University | Hall D.M.,Texas A&M University | Feldpausch-Parker A.M.,Texas A&M University | Peterson T.R.,Texas A&M University | Peterson T.R.,Swedish University of Agricultural Sciences
Conservation Biology | Year: 2010

Conservationists commonly have framed ecological concerns in economic terms to garner political support for conservation and to increase public interest in preserving global biodiversity. Beginning in the early 1980s, conservation biologists adapted neoliberal economics to reframe ecosystem functions and related biodiversity as ecosystem services to humanity. Despite the economic success of programs such as the Catskill/Delaware watershed management plan in the United States and the creation of global carbon exchanges, today's marketplace often fails to adequately protect biodiversity. We used a Marxist critique to explain one reason for this failure and to suggest a possible, if partial, response. Reframing ecosystem functions as economic services does not address the political problem of commodification. Just as it obscures the labor of human workers, commodification obscures the importance of the biota (ecosystem workers) and related abiotic factors that contribute to ecosystem functions. This erasure of work done by ecosystems impedes public understanding of biodiversity. Odum and Odum's radical suggestion to use the language of ecosystems (i.e., emergy or energy memory) to describe economies, rather than using the language of economics (i.e., services) to describe ecosystems, reverses this erasure of the ecosystem worker. Considering the current dominance of economic forces, however, implementing such solutions would require social changes similar in magnitude to those that occurred during the 1960s. Niklas Luhmann argues that such substantive, yet rapid, social change requires synergy among multiple societal function systems (i.e., economy, education, law, politics, religion, science), rather than reliance on a single social sphere, such as the economy. Explicitly presenting ecosystem services as discreet and incomplete aspects of ecosystem functions not only allows potential economic and environmental benefits associated with ecosystem services, but also enables the social and political changes required to ensure valuation of ecosystem functions and related biodiversity in ways beyond their measurement on an economic scale. © 2009 Society for Conservation Biology.

Zydor A.,Tyndall National Institute | Kessler V.G.,Swedish University of Agricultural Sciences | Elliott S.D.,Tyndall National Institute
Physical Chemistry Chemical Physics | Year: 2012

It is a common finding that titanocene-derived precursors do not yield TiO 2 films in atomic layer deposition (ALD) with water. For instance, ALD with Ti(OMe) 4 and water gives 0.5 Å/cycle, while TiCp*(OMe) 3 does not show any growth (Me = CH 3, Cp* = C 5(CH 3) 5). From mass spectrometry we found that Ti(OMe) 4 occurs in the gas phase practically exclusively as a monomer. We then used first principles density functional theory (DFT) to model the ALD reaction sequence and find the reason for the difference in growth behaviour. Both precursors adsorb initially via hydrogen-bonding. The simulations reveal that the Cp* ligand of TiCp*(OMe) 3 lowers the Lewis acidity of the Ti centre and prevents its coordination to surface O ('densification') during both of the ALD pulses. The effect of Cp* on Ti seems to be both steric (full coordination sphere) and electronic (lower electrophilicity). This crucial step in the sequence of ALD reactions is therefore not possible in the case of TiCp*(OMe) 3 + H 2O, which means that there is no deposition of TiO 2 films. © 2012 the Owner Societies.

Wu J.,Memorial University of Newfoundland | Roulet N.T.,McGill University | Sagerfors J.,Swedish University of Agricultural Sciences | Nilsson M.B.,Swedish University of Agricultural Sciences
Journal of Geophysical Research: Biogeosciences | Year: 2013

Northern peatlands store ~30% of the global soil carbon, despite covering only 3% of the land. To understand the carbon balance of these systems and predict their response to changes in climate, robust and reliable models are needed. The McGill Wetland Model (MWM), originally developed to simulate the carbon dynamics of ombrotrophic bogs, was modified to simulate the CO 2 biogeochemistry of sedge-dominated oligotrophic minerogenic peatlands, a prominent peatland type in boreal and subarctic landscapes. Three modifications were implemented: (1) a function to describe the impact of soil moisture on the optimal gross primary production, (2) a scheme to partition the peat profile into oxic and anoxic compartments based on the "effective root depth" as a function of daily sedge net primary production, and (3) a function to describe the "fen" moss water dynamics. The modified MWM was evaluated using eddy-covariance net ecosystem production (NEP) from Degero Stormyr in northern Sweden. The root mean square error for daily NEP was ~0.46 g C m-2 d-1, and the index of agreement was 84%. This model adequately captures the magnitude and direction of the CO2 fluxes and simulates the seasonal and inter-annual variability reasonably well (r 2 > 0.8). Sensitivity analysis confirms that specifically water table depth (WTD) and moss water content are key biogeochemical hydrology processes for the carbon biogeochemistry of a sedge-dominated oligotrophic minerogenic peatland. An increase of WTD by 15 cm or air temperature by 3°C could decrease NEP by up to 200% and make the peatland become a source of CO2. Key PointsSimulations of the CO2 exchanges from a sedge-dominated peatlandWater table and moss water content, are the key environmental variablesSedge-dominated peatlands may not continue as a sink of CO2 ©2013. American Geophysical Union. All Rights Reserved.

Marshall J.D.,University of Idaho | Marshall J.D.,Umeå University | Linder S.,Swedish University of Agricultural Sciences
Tree Physiology | Year: 2013

The effects of the past century's increase in atmospheric CO2 concentration ([CO2]) have been recorded in the stable carbon isotope composition (13C) of the annual growth rings of trees. The isotope record frequently shows increases in photosynthetic CO2 uptake relative to stomatal conductance, which estimates the CO2 concentration gradient across the stomata (ca -ci). This variable, which is one control over the net photosynthetic rate, has been suggested as a homeostatic gas-exchange set point that is easy to estimate from 13C and [CO2]. However, in high-latitude conifer forests, the literature is mixed; some studies show increases in (ca -c i) and others show homeostasis. Here we present leaf and tree-ring 13C data from a controlled experiment that tested factorial combinations of elevated [CO2] (365 and 700 ∝mol mol -1) and fertilization on mature Norway spruce (Picea abies (L.) Karst.) trees in northern Sweden. We found first that the leaf carbon pool was contaminated by the current photosynthate in the older leaf cohorts. This is the reverse of the common observation that older photosynthate reserves can be used to produce new tissue; here the older tissue contains recent photosynthate. We found that the tree-ring data lack such contamination and in any case they better integrate over the canopy and the growing season than do leaves. In the second and third years of treatment, elevated [CO2] alone increased (ca -ci) by 38%; when combined with fertilization, it increased (ca -ci) by 60%. The results of this study support the idea that annual rings provide a clearer isotopic signal than do foliage age-classes. The tree-ring data show that inferred (ca -ci) depends not only on [CO2], but also on mineral-nutrient status. The differences in (ca -ci) are sufficiently large to account for the treatment-induced increase in wood-volume production in these stands. © 2013 The Author.

Axelsson E.P.,Swedish University of Agricultural Sciences | Hjalten J.,Swedish University of Agricultural Sciences | LeRoy C.J.,Evergreen State College
Forest Ecology and Management | Year: 2012

The intent with insect-resistant transgenic trees is to increase yield without adverse negative effects on non-target organisms. Thus, the assessment of these products is dependent on not only performance, but also on environmental effects realized in the field. With this study we transition from greenhouse evaluations to assessments under semi-natural field conditions with the objectives: (i) to assess the realized benefits (biomass production and resistance effectiveness) and (ii) to evaluate effects on the biotic interactions of two isogenic transgenic Bt (Bacillus thuringiensis, cry3Aa targeting coleopteran leaf beetles)-expressing aspens. We established an experiment with a total of 108 potted aspen plants (n= 36 for three different lines) in the field and applied an additional experimental nutrient treatment to reflect the effects of one aspect of environmental variability. Overall leaf damage was shown to be higher on the un-modified wild type (Wt) plants compared to plants from the high expression line (P= 0.003), and the same trend was also detected for the low expression line (P= 0.089). However, despite this advantage in resistance, biomass production was not significantly enhanced in insect-resistant plants. Also, whereas the high nutrient treatment showed an increase in biomass, it did not affect the amount of leaf damage inflicted on the plants. Presence/absence surveys of biotic interactions during the study showed that the number of plants that were scored for the presence of three insect orders and two leaf modifications was equal regardless of line treatment. Interestingly, one species included in the presumably targeted order, the leaf rolling beetle Byctiscus populi (Coleoptera) inflicted the insect-resistant plants with oviposition and feeding damage to a similar degree as the un-modified Wt plants. © 2011 Elsevier B.V.

Fritz O.,Swedish University of Agricultural Sciences | Heilmann-Clausen J.,Skaelskorvej 22
Biological Conservation | Year: 2010

Identification of trees with key microhabitats as well as knowledge of their ecological formation is important for the conservation of epiphytic bryophytes and lichens on beech. Based on the hypothesis that certain types of stem damage are crucial for the occurrence of epiphytes of conservation concern, we surveyed 145 beech trees (57-280 years) for different types of stem damage and analysed their relationship to other tree characteristics, epiphyte species and wood-inhabiting fungi in a forest landscape on acid soils. Three main types of stem damage were identified; canker, rot hole and surface rot. The incidence of rot holes was highest on trees with a low growth rate during the last 50 years, but was unrelated to tree size or age per se. Bark pH was significantly higher below than above rot holes, whereas no such relationship was found for cankers. Wood mould from rot holes had a very high pH, explaining the higher bark pH below this type of damage. The number of epiphyte species of conservation concern was strongly positively related to rot holes and high bark pH. Cankers had a weaker, yet significant positive effect. The fungus Psathyrella cernua was associated with the rot holes and is suggested to be a key species involved in creating this microhabitat. We conclude that slow-growing trees with rot holes are important for the conservation of epiphytes and should be selected as retention trees in managed forests. The study also highlights a potential for habitat restoration by inducing artificial damage and inoculation of decay fungi in beech trees. © 2010 Elsevier Ltd. All rights reserved.

Rundlof M.,Lund University | Andersson G.K.S.,Lund University | Bommarco R.,Swedish University of Agricultural Sciences | Fries I.,Swedish University of Agricultural Sciences | And 7 more authors.
Nature | Year: 2015

Understanding the effects of neonicotinoid insecticides on bees is vital because of reported declines in bee diversity and distribution and the crucial role bees have as pollinators in ecosystems and agriculture. Neonicotinoids are suspected to pose an unacceptable risk to bees, partly because of their systemic uptake in plants, and the European Union has therefore introduced a moratorium on three neonicotinoids as seed coatings in flowering crops that attract bees. The moratorium has been criticized for being based on weak evidence, particularly because effects have mostly been measured on bees that have been artificially fed neonicotinoids. Thus, the key question is how neonicotinoids influence bees, and wild bees in particular, in real-world agricultural landscapes. Here we show that a commonly used insecticide seed coating in a flowering crop can have serious consequences for wild bees. In a study with replicated and matched landscapes, we found that seed coating with Elado, an insecticide containing a combination of the neonicotinoid clothianidin and the non-systemic pyrethroid β-cyfluthrin, applied to oilseed rape seeds, reduced wild bee density, solitary bee nesting, and bumblebee colony growth and reproduction under field conditions. Hence, such insecticidal use can pose a substantial risk to wild bees in agricultural landscapes, and the contribution of pesticides to the global decline of wild bees may have been underestimated. The lack of a significant response in honeybee colonies suggests that reported pesticide effects on honeybees cannot always be extrapolated to wild bees. ©2015 Macmillan Publishers Limited. All rights reserved.

Hytteborn H.,Uppsala University | Hytteborn H.,Norwegian University of Science and Technology | Verwijst T.,Swedish University of Agricultural Sciences
Journal of Vegetation Science | Year: 2014

Questions: Can assumptions of the existence of spatially distinct patches (delineated structurally homogeneous parts of the forest, being either areas consisting of canopy trees or areas without canopy trees but in an early or later regenerative phase) and of directional development over time of the vegetation in such patches, as implied by current theory of storm gap dynamics, be verified by remapping previous study sites? Location: Natural, unmanaged boreo-nemoral spruce-dominated forest in eastern central Sweden. Methods: By re-mapping three plots, ca, 50 yr after the first inventory, we studied the structure and dynamics of gaps (patches without canopy tree cover) and major tree populations. The old and new maps allowed us to compare two independent assessments of the forest dynamics: one based on tree population changes and one on changes in gap area over time. Results: The current population structure could partly be described through the earlier-encountered structures of the different tree populations and consecutive processes of recruitment and mortality. However, the re-mapping exercise showed that spatially delineated patches did not develop directionally over time, nor was their development spatially discrete. Conclusions: Patch dynamics proceeds in such a way that the fate of a single patch may depend on the development of neighbouring patches. As gaps may partly close or merge into larger gaps, and as gap disappearance rate is a function of actual gap size, performance of an initially delimited patch is largely determined by developments in neighbouring patches and cannot be predicted from its momentary patch characteristics. Consequently, we propose an 'open matrix model' to describe the changes in a boreo-nemoral spruce forest, rather than a 'storm gap dynamics' model. © 2013 International Association for Vegetation Science.

Fregin S.,University of Greifswald | Haase M.,University of Greifswald | Olsson U.,Gothenburg University | Alstrom P.,Swedish University of Agricultural Sciences
Molecular Phylogenetics and Evolution | Year: 2012

Genetic distances are increasingly being used for identification and species delimitation, especially since the introduction of "barcoding" While for phylogenetic inferences great care is generally taken to choose the best-fit evolutionary model, this is usually neglected in calculating genetic distances. Moreover, distances obtained from others than best-fit models, different lengths of sequences, and even different loci are often freely compared. We examined the influence of different methods on calculating genetic distances using mitochondrial cytochrome b sequences for the passerine family Acrocephalidae. We found substantial differences between: (1) corrected distances based on the best-fit model (TrN + Γ) vs. uncorrected p-distances; (2) distances calculated based on different parts of the same gene; and (3) distances calculated using the methods of "complete deletion" vs "pairwise deletion" for sequences that included uncertain nucleotides. All these methodological differences affected comparisons between species and potential taxonomical conclusions. We suggest that (1) different loci are incomparable. (2) Only perfectly homologous regions (same length, same part of locus) should be compared. (3) In the case of sequences with some uncertain nucleotides, only distances calculated by the method of "complete deletion" are fully comparable. (4) Only distances based on the optimal substitution model should be used. (5) Even within the same locus, corrected genetic distances are unique to the study in which they are calculated, as they are conditional on the particular dataset and model selected for that dataset. © 2011 Elsevier Inc.

Bundschuh M.,Swedish University of Agricultural Sciences | Bundschuh M.,University of Koblenz-Landau | Goedkoop W.,Swedish University of Agricultural Sciences | Kreuger J.,Swedish University of Agricultural Sciences
Science of the Total Environment | Year: 2014

The European Water Framework Directive requires surface water bodies to have a good chemical and ecological status. Although relatively few pesticides are included in the list of priority pollutants, they pose, due to their intrinsic biological activity, a significant risk for the integrity of aquatic ecosystems. In this context, the pesticide (up to 128 pesticides including some transformation products) exposure pattern in four agricultural streams and two rivers was determined from 2002 to 2011 under the umbrella of the Swedish national monitoring program employing time-proportional and grab sampling strategies, respectively. After transforming the measured pesticide concentrations into toxic units, the European Uniform Principles for algae (chronic), invertebrates and fish (both acute), which are partly employed as benchmark for pesticide regulation, were only occasionally (<. 2%) exceeded. Moreover, this evaluation showed no long-term trends over the years. However, recent publications suggested that those thresholds are not protective for ecosystem structure and function, indicating a risk of up to 20% and 35% of the samples from the agricultural streams and the rivers, respectively. Moreover, the monitoring data show a continuous but rather low toxic potential of pesticides for all three trophic levels throughout the year, which suggests pesticides as an evolutionary force in agriculturally impacted aquatic ecosystems. However, the flow-triggered sampling, which was implemented as an additional sampling strategy in one of the agricultural streams starting in 2006, displayed an up to 7-fold underestimation of the maximum concentration in terms of toxic units for daphnids and fish during run-off events. The present study thus underpins that the optimal sampling design for pesticide monitoring strongly depends on its overall purpose. If the long-term exposure pattern is of concern a time-proportional composite sampling strategy is recommended, while for an assessment of peak exposures a flow-event-triggered high-resolution sampling strategy is superior. © 2014 Elsevier B.V.

Berglund S.L.,Swedish University of Agricultural Sciences | Agren G.I.,Swedish University of Agricultural Sciences | Ekblad A.,Örebro University
Soil Biology and Biochemistry | Year: 2013

The decomposition rate of litter mixtures can differ from that expected on the basis of the decomposition rate of the individual components. This difference may be linked to nitrogen (N) transfer from high-N to low-N components. Transfer of N is probably also associated with transfer of C, but the extent and direction of this C transfer are unknown. This study examined transfer and loss in laboratory microcosms of C and N from two mixed litter species (Scots pine, Pinus sylvestris L. and maize, Zea mays L.), which have natural isotopic differences in 13C. Half the material was 15N-labelled and the plants were fertilised or unfertilised. Substantial bidirectional transfer of C and N occurred between the litters, with net transfer of C from pine to maize litter and net transfer of N from high-N to low-N litter. Mixtures of fertilised and unfertilised plant litter showed higher than expected C losses and net transfer of N. Mixtures with litters from the same fertilisation treatment had small or insignificant net transfer of N and their C losses did not differ from values estimated using the decomposition rates of the pure litters. © 2012 Elsevier Ltd.

Asplund J.,Norwegian University of Life Sciences | Wardle D.A.,Swedish University of Agricultural Sciences
Biological Reviews | Year: 2016

Lichens occur in most terrestrial ecosystems; they are often present as minor contributors, but in some forests, drylands and tundras they can make up most of the ground layer biomass. As such, lichens dominate approximately 8% of the Earth's land surface. Despite their potential importance in driving ecosystem biogeochemistry, the influence of lichens on community processes and ecosystem functioning have attracted relatively little attention. Here, we review the role of lichens in terrestrial ecosystems and draw attention to the important, but often overlooked role of lichens as determinants of ecological processes. We start by assessing characteristics that vary among lichens and that may be important in determining their ecological role; these include their growth form, the types of photobionts that they contain, their key functional traits, their water-holding capacity, their colour, and the levels of secondary compounds in their thalli. We then assess how these differences among lichens influence their impacts on ecosystem and community processes. As such, we consider the consequences of these differences for determining the impacts of lichens on ecosystem nutrient inputs and fluxes, on the loss of mass and nutrients during lichen thallus decomposition, and on the role of lichenivorous invertebrates in moderating decomposition. We then consider how differences among lichens impact on their interactions with consumer organisms that utilize lichen thalli, and that range in size from microfauna (for which the primary role of lichens is habitat provision) to large mammals (for which lichens are primarily a food source). We then address how differences among lichens impact on plants, through for example increasing nutrient inputs and availability during primary succession, and serving as a filter for plant seedling establishment. Finally we identify areas in need of further work for better understanding the role of lichens in terrestrial ecosystems. These include understanding how the high intraspecific trait variation that characterizes many lichens impacts on community assembly processes and ecosystem functioning, how multiple species mixtures of lichens affect the key community- and ecosystem-level processes that they drive, the extent to which lichens in early succession influence vascular plant succession and ecosystem development in the longer term, and how global change drivers may impact on ecosystem functioning through altering the functional composition of lichen communities. © 2016 Cambridge Philosophical Society.

Cudmore T.J.,University of Northern British Columbia | Bjorklund N.,Swedish University of Agricultural Sciences | Carroll A.L.,University of British Columbia | Staffan Lindgren B.,University of Northern British Columbia
Journal of Applied Ecology | Year: 2010

1. Hosts may evolve defences that make them less susceptible and suitable to herbivores impacting their fitness. Due to climate change-driven range expansion, herbivores are encountering naïve host populations with increasing frequency.2. Aggressive bark beetles are among the most important agents of disturbance in coniferous forest ecosystems. The presence of bark beetle outbreaks in areas with a historically unsuitable climate, in part a consequence of climate change, provided an opportunity to assess the hypothesis that the mountain pine beetle Dendroctonus ponderosae has higher reproductive success in lodgepole pine Pinus contorta trees growing in areas that have not previously experienced frequent outbreaks.3. We felled and sampled mountain pine beetle-killed trees from historically climatically suitable and unsuitable areas, i.e. areas with and without a historical probability of frequent outbreaks. Reproductive success was determined from a total of 166 trees from 14 stands.4. Brood productivity was significantly affected by climatic suitability class, such that mean brood production per female increased as historical climatic suitability decreased.5. Synthesis and applications. The current study demonstrates that the mountain pine beetle has higher reproductive success in areas where its host trees have not experienced frequent beetle epidemics, which includes much of the current outbreak area in north central British Columbia. This increased productivity of mountain pine beetle is likely to have been a key reason for the rapid population buildup that resulted in unprecedented host tree mortality over huge areas in western Canada. The outbreak thus provides an example of how climate change-driven range expansion of native forest insects can have potentially disastrous consequences. Since an increased reproductive success is likely to accelerate the progression of outbreaks, it is particularly critical to manage forests for the maintenance of a mosaic of species and age classes at the landscape level in areas where host tree populations are naïve to eruptive herbivores. © 2010 The Authors. Journal compilation © 2010 British Ecological Society.

Baum S.,Johann Heinrich Von Thunen Institute | Bolte A.,Johann Heinrich Von Thunen Institute | Weih M.,Swedish University of Agricultural Sciences
GCB Bioenergy | Year: 2012

The demand for wood from short rotation coppice (SRC) plantations as a renewable energy source is currently increasing and could affect biodiversity in agricultural areas. The objective was to evaluate the contribution of SRC plantations to phytodiversity in agricultural landscapes assessed as species richness, species-area relationships, Shannon indices, detrended correspondence analysis on species composition, Sørensen similarities, habitat preference proportions, and species proportions found in only one land use. Vegetation surveys were conducted on 12 willow (Salix spp.) and three poplar (Populus spp.) coppice sites as well as on surrounding arable lands, grasslands and forests in central Sweden and northern Germany. SRC plantations were richer in plant species (mean: 30 species per 100 m 2) than arable land (10), coniferous forests (13) and mixed forests in Germany (12). Comparing SRC plantations with other land uses, we found lowest similarities in species composition with arable lands, coniferous forests and German mixed forests and highest similarities with marginal grassland strips, grasslands and Swedish mixed forests. Similarity depended on the SRC tree cover: at increased tree cover, SRC plantations became less similar to grasslands but more similar to forests. The SRC plantations were composed of a mixture of grassland (33%), ruderal (24%) and woodland (15%) species. Species abundance in SRC plantations was more heterogeneous than in arable lands. We conclude that SRC plantations form novel habitats leading to different plant species composition compared to conventional land uses. Their landscape-scale value for phytodiversity changes depending on harvest cycles and over time. As a structural landscape element, SRC plantations contribute positively to phytodiversity in rural areas, especially in land use mosaics where these plantations are admixed to other land uses with dissimilar plant species composition such as arable land, coniferous forest and, at the German sites, also mixed forest. © 2012 Blackwell Publishing Ltd.

Nicolia A.,University of Perugia | Nicolia A.,Swedish University of Agricultural Sciences | Manzo A.,Ministry of Agriculture | Veronesi F.,University of Perugia | Rosellini D.,University of Perugia
Critical Reviews in Biotechnology | Year: 2014

The technology to produce genetically engineered (GE) plants is celebrating its 30th anniversary and one of the major achievements has been the development of GE crops. The safety of GE crops is crucial for their adoption and has been the object of intense research work often ignored in the public debate. We have reviewed the scientific literature on GE crop safety during the last 10 years, built a classified and manageable list of scientific papers, and analyzed the distribution and composition of the published literature. We selected original research papers, reviews, relevant opinions and reports addressing all the major issues that emerged in the debate on GE crops, trying to catch the scientific consensus that has matured since GE plants became widely cultivated worldwide. The scientific research conducted so far has not detected any significant hazards directly connected with the use of GE crops; however, the debate is still intense. An improvement in the efficacy of scientific communication could have a significant impact on the future of agricultural GE. Our collection of scientific records is available to researchers, communicators and teachers at all levels to help create an informed, balanced public perception on the important issue of GE use in agriculture. © 2014 Informa Healthcare USA, Inc. All rights reserved: reproduction in whole or part not permitted.

Wallentin C.,Holmen Skog | Nilsson U.,Swedish University of Agricultural Sciences
Forestry | Year: 2014

To assess uncertainties regarding the effects of thinning on risks of storm and snow damage, three thinning treatments (control, normal and heavy: 0, 30 and 61 per cent basal area removal, respectively)with four replicationswere applied in a 33-year-old Norway spruce plantation on a fertile site in south-west Sweden. Amajor storm event occurred three growing seasons after thinning followed by snow damage 2 months later and another storm 2 years later. There was a near-linear relationship between thinning intensity and damage caused by the first storm (adj R2 = 0.94): 7, 42 and 74 per cent of the standing basal area was damaged in the control, normally and heavily thinned plots, respectively. Corresponding percentages after both the storm and snow damage were also approximately linearly correlated with thinning intensity: 8, 53 and 89 per cent, respectively (adj R2 = 0.91). Damage caused by the second storm was related to both previous damage levels and standing basal area in the control and normally thinned plots. Stem taper between breast height and 6 mstemheight was negatively correlated with risk for stormand snow damage in the normally thinned plots. Of the trees categorized as damaged (up-rooted, broken or heavily leaning), the frequency of stembreakage after the first stormwas almost negligible in the normally thinned plots, (,5 per cent),while 24-50 per cent of the damaged stemswere broken (mean, 36 per cent) in the heavily thinned plots. The relative diameter growth of the remaining trees in the control plots, for the first and second growing seasons following the storm and snow damage, were significantly decreased compared with the three preceding years. The results confirm previous findings that increasing thinning intensity increases risks of windfall and highlight the need for new Norway spruce management programmes if climate change results in more frequent storm events. © Institute of Chartered Foresters, 2013.

Walther Y.M.,Swedish University of Agricultural Sciences | Mollmann C.,University of Hamburg
ICES Journal of Marine Science | Year: 2014

An ecosystem approach to management (EAM) aims to secure a healthy ecosystem along with sustainable use of its goods and services. Although the main principles of EAM are agreed upon and desirable, wider implementation of EAM is still a challenge. The difficulties stem from unclear definition and communication of the EAM, lack of routines or protocols to develop ecosystem-based advice, inappropriate institutional structures, and communication issues between scientists, advisers, and managers. Integrated ecosystem assessment (IEA) is an instrument that has proven to help in the implementation of EAM. For successful implementation of EAM and IEA in the European regional seas context, an international forum is required that develops tailor-made EAM tools specific to the different regional ecosystems to overcome fragmented national strategies. We describe a multinational peer network of working groups developed within the International Council for the Exploration of the Sea (ICES) under the auspice of Science Steering Group on Regional Sea Programmes. Available is a wealth of data, expertise, scientific methods, and models for each regional sea. This network can be instrumental in advancing IEA for the implementation of EAM in the North Atlantic seas. © 2014 International Council for the Exploration of the Sea. All rights reserved.

Tran K.-Q.,Norwegian University of Science and Technology | Bach Q.-V.,Norwegian University of Science and Technology | Trinh T.T.,Norwegian University of Science and Technology | Seisenbaeva G.,Swedish University of Agricultural Sciences
Applied Energy | Year: 2014

The pyrolysis of native and torrefied stump materials was studied in the kinetic regime by means of a thermogravimetric analyzer operated in the non-isothermal fashion. Three different kinetic models applicable to biomass pyrolysis were evaluated for the collected data, which include a single-reaction model, two three pseudo-components models, and a distributed activation energy model (DAEM). It was shown that the single-reaction model was not suitable to simulating stump biomass pyrolysis. The other models including the three pseudo-components model with n = 1 and n ≠ 1, and the DAEM demonstrated very good fits between simulated and experimental curves. However, the three pseudo-components model with n ≠ 1 is recommended as the most suitable for simulation and prediction of kinetic behaviour of slow pyrolysis for both untreated and torrefied stump, considering that it offers the best fits to the experimental data and that the generated reaction orders are realistic, being slightly higher than unity. It appears that the torrefied stump has higher activation energy than its native material. The activation energy predicted for the native stump pyrolysis is in the range of 105.2-108.9 kJ/mol, 183.5-183.6 kJ/mol, and 40.3-48.01 kJ/mol for hemicelluloses, celluloses, and lignin, respectively. That for pyrolysis of the stump torrefied at 200 °C is 105.13-111.19 kJ/mol, 183.68-185.79 kJ/mol, and 40.49-50.70 kJ/mol, respectively. © 2014 Elsevier Ltd. All rights reserved.

Peters K.,University of Koblenz-Landau | Bundschuh M.,University of Koblenz-Landau | Bundschuh M.,Swedish University of Agricultural Sciences | Schafer R.B.,University of Koblenz-Landau
Environmental Pollution | Year: 2013

We reviewed 122 peer-reviewed studies on the effects of organic toxicants and heavy metals on three fundamental ecosystem functions in freshwater ecosystems, i.e. leaf litter breakdown, primary production and community respiration. From each study meeting the inclusion criteria, the concentration resulting in a reduction of at least 20% in an ecosystem function was standardized based on median effect concentrations of standard test organisms (i.e. algae and daphnids). For pesticides, more than one third of observations indicated reductions in ecosystem functions at concentrations that are assumed being protective in regulation. Moreover, the reduction in leaf litter breakdown was more pronounced in the presence of invertebrate decomposers compared to studies where only microorganisms were involved in this function. High variability within and between studies hampered the derivation of a concentration -effect relationship. Hence, if ecosystem functions are to be included as protection goal in chemical risk assessment standardized methods are required. © 2013 Elsevier Ltd. All rights reserved.

Eriksen S.H.,Norwegian University of Life Sciences | Nightingale A.J.,Norwegian University of Life Sciences | Nightingale A.J.,Swedish University of Agricultural Sciences | Eakin H.,Arizona State University
Global Environmental Change | Year: 2015

This paper is motivated by a concern that adaptation and vulnerability research suffer from an under-theorization of the political mechanisms of social change and the processes that serve to reproduce vulnerability over time and space. We argue that adaptation is a socio-political process that mediates how individuals and collectives deal with multiple and concurrent environmental and social changes. We propose that applying concepts of subjectivity, knowledges and authority to the analysis of adaptation focuses attention on this socio-political process. Drawing from vulnerability, adaptation, political ecology and social theory literatures, we explain how power is reproduced or contested in adaptation practice through these three concepts. We assert that climate change adaptation processes have the potential to constitute as well as contest authority, subjectivity and knowledge, thereby opening up or closing down space for transformational adaptation. We expand on this assertion through four key propositions about how adaptation processes can be understood and outline an emergent empirical research agenda, which aims to explicitly examine these propositions in specific social and environmental contexts. We describe how the articles in this special issue are contributing to this nascent research agenda, providing an empirical basis from which to theorize the politics of adaptation. The final section concludes by describing the need for a reframing of adaptation policy, practice and analysis to engage with multiple adaptation knowledges, to question subjectivities inherent in discourses and problem understandings, and to identify how emancipatory subjectivities - and thus the potential for transformational adaptation - can be supported. © 2015 Elsevier Ltd.

Asplund J.,Swedish University of Agricultural Sciences | Asplund J.,Norwegian University of Life Sciences | Wardle D.A.,Swedish University of Agricultural Sciences
Functional Ecology | Year: 2014

There has been growing recent interest in the relative importance of within-species trait variation vs. across-species trait variation in vascular plants in determining total community-level trait variation across communities and environmental gradients. Recent studies on plant communities have generally found across-species variation to be more important than within-species variation, but comparable studies involving other functionally important biota, such as lichens, are largely lacking. We used a fire-driven chronosequence involving 30 lake islands in northern Sweden to study how declining soil fertility during retrogression affects the functional traits of each of the dominant epiphytic lichen species growing on the trunks of the tree Betula pubescens. We measured several functional traits for the commonest lichen species on each island and used community-weighted measures to study the community-level responses of lichens to the gradient. We found that as retrogression proceeds and soil fertility declines, thallus N and P concentrations and specific thallus mass (STM) increase, both within species and at the community level. Lichen secondary compounds showed contrasting within-species responses and were non-responsive at the whole community level. By decomposing community-level measures of these traits across the gradient, we showed that for the three most responsive traits (N, P and STM), within-species variation was substantially more important than across-species variation. This emerges in part because lichen species composition was not very responsive to ecosystem retrogression, and because unlike vascular plants, lichens easily absorb elements over their entire surface, meaning that nutrient concentrations within lichen species are likely to more closely reflect nutrient availability. We found that within-species variability drove the changes in community-weighted measures of lichen traits across a strong environmental gradient, which contrasts strongly with what we know from studies of vascular plants where across-species variation and species turnover is much more important. To understand how lichen functional traits at the community level respond to environmental factors, it is therefore essential to consider the responses of individual species, and the application of traits-based approaches to lichen communities needs to account for their considerable intraspecific variability. © 2014 British Ecological Society.

Naesset E.,Norwegian University of Life Sciences | Bollandsas O.M.,Norwegian University of Life Sciences | Gobakken T.,Norwegian University of Life Sciences | Gregoire T.G.,Yale University | Stahl G.,Swedish University of Agricultural Sciences
Remote Sensing of Environment | Year: 2013

The United Nations Collaborative Program on Reduced Emissions from Deforestation and Forest Degradation in Developing Countries (UN REDD) was launched with the aim of contributing to the development of capacity for reducing emissions from loss of forest carbon in developing countries. It is understood that REDD mechanisms must be supported by forest assessment programs that can monitor the carbon stocks by carbon pools and human activities. Reporting at a national level will be required but many countries are likely to benefit from more local monitoring programs within the countries as well, gauging the effects of national policies and local financial mechanisms aimed at reaching goals for emission control for the nation as a whole. Field-based forest sample surveys are typically used as support for national reporting purposes. However, monitoring within the countries will require huge investments in field surveys to provide reliable change estimates with high spatial and temporal resolution. Airborne scanning LiDAR has emerged as a promising tool to provide auxiliary data for sample surveys aiming at estimation of above-ground tree biomass. The aim of this study was to demonstrate how "wall-to-wall" LiDAR data can be used for change estimation. Estimators for areal changes of categories representing human activities such as "deforestation", "degradation" and "untouched" were presented. Corresponding estimators for variance were also provided. Furthermore, it was shown how net change in biomass for the defined activity categories and for the entire area of interest can be estimated from a field sample survey with and without support of LiDAR remote sensing data and how the uncertainty can be quantified by corresponding variance estimates. In a case study in a small boreal forest area in southeastern Norway (852.6. ha) a probability sample of 176 field sample plots distributed according to a stratified systematic design was measured twice over an 11. year period. Corresponding multi-temporal scanning LiDAR data were also available. A multinomial logistic regression model was used to predict change category for every LiDAR grid cell in the area, and areal changes were estimated from the pure field sample and with the support of the LiDAR data applying model-assisted estimators. The standard errors of the areal change estimates were reduced by 43-75% by adding LiDAR data to the estimation. The change categories were used as post-strata in a subsequent estimation of net change in biomass. The standard errors of the biomass change estimates for the respective change categories were reduced by 18-84% compared to the pure field survey when using LiDAR data as auxiliary information in a model-assisted estimation procedure, which translates to a need for 1.5-38.7 times as many field plots when relying only on the field data. For the entire area of interest, the standard error of the overall net change in biomass was reduced by 57% compared to the uncertainty reported from the pure field survey. © 2012 Elsevier Inc.

Asplund J.,Swedish University of Agricultural Sciences | Asplund J.,Norwegian University of Life Sciences | Wardle D.A.,Swedish University of Agricultural Sciences
Journal of Ecology | Year: 2013

There has been much recent interest in understanding how functional traits of vascular plant species drive ecological processes such as herbivory and litter decomposition. In plants, these two processes are often driven by the same or similar suites of traits and therefore correlate across species. However, few studies have considered how traits of plant-like life forms such as lichens determine species differences in their effects on ecological processes. This is despite the significant contribution of lichens to carbon and nutrient cycling in many environments. We collected 28 lichen species that differed in their growth form, substrate type and capacity to fix N, and determined key traits for each species. For each species, we performed a feeding bioassay using the generalist snail Cepaea hortensis and carried out a laboratory bioassay to assess decomposability. We did these tests both with intact lichen material containing natural concentrations of carbon-based secondary compounds (CBSCs), and material that had been acetone rinsed to reduce concentrations of CBSCs, to evaluate the effect of CBSC on palatability and decomposability. We found that reducing CBSC concentrations greatly increased palatability for 17 species, and decomposability of 10 species. However, decomposability was correlated with several lichen traits while palatability was not, regardless of whether or not CBSCs were removed, and we therefore found no relationship between decomposability and palatability across species. Decomposability and palatability both varied, but in contrasting directions, among N-fixing vs. non-fixing lichens, lichens with different growth forms and those from contrasting substrate types. As such, N-fixing lichens had higher decomposition rates but lower consumption rates than non-fixing lichens, while foliose species had higher decomposition rates but lower consumption rates than fruticose species. Synthesis: We have shown that lichen CBSCs regulate key processes such as lichenivory and decomposition, that lichen decomposability but not palatability are related to traits, and that these two processes are unrelated across species. These results highlight the potential role of lichen species differences in influencing ecosystem processes relating to decomposition and nutrient cycling and the role that grazers may play in driving this. We have shown that lichen carbon-based secondary compounds (CBSCs) regulate key processes such as lichenivory and decomposition, that lichen decomposability but not palatability are related to traits, and that these two processes are unrelated across species. These results highlight the potential role of lichen species differences in influencing ecosystem processes relating to decomposition and nutrient cycling and the role that grazers may play in driving this. © 2013 The Authors. Journal of Ecology © 2013 British Ecological Society.

Zheng Z.,Salk Institute for Biological Studies | Guo Y.,Salk Institute for Biological Studies | Novak O.,Swedish University of Agricultural Sciences | Novak O.,Palacky University | And 4 more authors.
Nature Plants | Year: 2016

A hallmark of plants is their adaptability of size and form in response to widely fluctuating environments. The metabolism and redistribution of the phytohormone auxin play pivotal roles in establishing active auxin gradients and resulting cellular differentiation. In Arabidopsis thaliana, cotyledons and leaves synthesize indole-3-acetic acid (IAA) from tryptophan through indole-3-pyruvic acid (3-IPA) in response to vegetational shade. This newly synthesized auxin moves to the hypocotyl where it induces elongation of hypocotyl cells. Here we show that loss of function of VAS2 (IAA-amido synthetase Gretchen Hagen 3 (GH3).17) leads to increases in free IAA at the expense of IAA-Glu (IAA-glutamate) in the hypocotyl epidermis. This active IAA elicits shade- and high temperature-induced hypocotyl elongation largely independently of 3-IPA-mediated IAA biosynthesis in cotyledons. Our results reveal an unexpected capacity of local auxin metabolism to modulate the homeostasis and spatial distribution of free auxin in specialized organs such as hypocotyls in response to shade and high temperature. © 2016 Macmillan Publishers Limited. All rights reserved.

Martinez G.,Ohio State University | Martinez G.,Swedish University of Agricultural Sciences | Panda K.,Ohio State University | Kohler C.,Swedish University of Agricultural Sciences | Slotkin R.K.,Ohio State University
Nature Plants | Year: 2016

Plant small interfering RNAs (siRNAs) communicate from cell to cell and travel long distances through the vasculature. However, siRNA movement into germ cells has remained controversial, and has gained interest because the terminally differentiated pollen vegetative nurse cell surrounding the sperm cells undergoes a programmed heterochromatin decondensation and transcriptional reactivation of transposable elements (TEs). Transcription of TEs leads to their posttranscriptional degradation into siRNAs, and it has been proposed that the purpose of this TE reactivation is to generate and load TE siRNAs into the sperm cells. Here, we identify the molecular pathway of TE siRNA production in the pollen grain and demonstrate that siRNAs produced from pollen vegetative cell transcripts can silence TE reporters in the sperm cells. Our data demonstrates that TE siRNAs act non-cell-autonomously, inhibiting TE activity in the germ cells and potentially the next generation. © 2016 Macmillan Publishers Limited. All rights reserved.

Ahrens L.,Swedish University of Agricultural Sciences | Bundschuh M.,Swedish University of Agricultural Sciences | Bundschuh M.,University of Koblenz-Landau
Environmental Toxicology and Chemistry | Year: 2014

Polyfluoroalkyl and perfluoroalkyl substances (PFASs) are distributed ubiquitously in the aquatic environment, which raises concern for the flora and fauna in hydrosystems. The present critical review focuses on the fate and adverse effects of PFASs in the aquatic environment. The PFASs are continuously emitted into the environment from point and nonpoint sources such as sewage treatment plants and atmospheric deposition, respectively. Although concentrations of single substances may be too low to cause adverse effects, their mixtures can be of significant environmental concern. The production of C8-based PFASs (i.e., perfluorooctane sulfonate [PFOS] and perfluorooctanoate [PFOA]) is largely phased out; however, the emissions of other PFASs, in particular short-chain PFASs and PFAS precursors, are increasing. The PFAS precursors can finally degrade to persistent degradation products, which are, in particular, perfluoroalkane sulfonates (PFSAs) and perfluoroalkyl carboxylates (PFCAs). In the environment, PFSAs and PFCAs are subject to partitioning processes, whereby short-chain PFSAs and PFCAs are mainly distributed in the water phase, whereas long-chain PFSAs and PFCAs tend to bind to particles and have a substantial bioaccumulation potential. However, there are fundamental knowledge gaps about the interactive toxicity of PFAS precursors and their persistent degradation products but also interactions with other natural and anthropogenic stressors. Moreover, because of the continuous emission of PFASs, further information about their ecotoxicological potential among multiple generations, species interactions, and mixture toxicity seems fundamental to reliably assess the risks for PFASs to affect ecosystem structure and function in the aquatic environment. © 2014 SETAC.

Tran K.-Q.,Norwegian University of Science and Technology | Luo X.,Swedish University of Agricultural Sciences | Seisenbaeva G.,Swedish University of Agricultural Sciences | Jirjis R.,Swedish University of Agricultural Sciences
Applied Energy | Year: 2013

A fixed bed reactor has been developed for study of biomass torrefaction, followed by thermogravimetric (TG) analyses. Norway spruce stump was used as feedstock. Two other types of biomass, poplar and fuel chips were also included in the study for comparison. Effects of feedstock types and process parameters such as torrefaction temperature and reaction time on fuel properties of torrefied solid product were investigated. The study has demonstrated that fuel properties, including heating values and grindability of the investigated biomasses were improved by torrefaction. Both torrefaction temperature and reaction time had strong effects on the torrefaction process, but temperature effects are stronger than effects of reaction time. At the same torrefaction temperature, the longer reaction time, the better fuel qualities for the solid product were obtained. However, too long reaction times and/or too higher torrefaction temperatures would decrease the solid product yield. The torrefaction conditions of 300. °C for 35. min resulted in the energy densification factor of 1.219 for the stump, which is higher than that of 1.162 for the poplar wood samples and 1.145 for the fuel chips. It appears that torrefied stump requires much longer time for grinding, while its particle size distribution is only slightly better than the others. In addition, the TG analyses have shown that untreated biomass was more reactive than its torrefaction products. The stump has less hemicelluloses than the two other biomass types. SEM analyses indicated that the wood surface structure was broken and destroyed by torrefaction process. © 2012 Elsevier Ltd.

Sverdrup-Thygeson A.,Norwegian University of Life Sciences | Sverdrup-Thygeson A.,Norwegian Institute for Nature Research | Gustafsson L.,Swedish University of Agricultural Sciences | Kouki J.,University of Eastern Finland
Biodiversity and Conservation | Year: 2014

Dead wood is a key substrate for forest biodiversity, hosting a rich and often threatened biodiversity of wood-living species. However, the relationship between the occurrence of dead wood and associated species is modified by several environmental factors. Here we review the present state of knowledge on how dead wood on different spatial and temporal scales affects saproxylic biodiversity. We searched for peer-reviewed studies on saproxylic species that compared dead wood distribution on at least two spatial or temporal scales. We scanned close to 300 articles, of which 34 fit our criteria. 20 studies were directed towards the current amount of dead wood at different scale levels and how this relates to the abundance or occurrence of saproxylic species, embracing scales from 10 m to 10 km. 14 studies compared time-lagged effects of dead wood, covering time-lags from 25 years to more than 200 years. The reviewed articles focused mainly on European forest and addressed invertebrates (mostly beetles), alone or in combination with fungi (27 articles), fungi (six articles), or lichens (one article). Although the significance of dead wood for forest biodiversity is firmly established, the reviewed studies show that we still have limited knowledge of the relationship between saproxylic biodiversity and spatial and temporal scales. Based on the reviewed studies, we conclude that there is large variation in response to spatial and temporal dead wood patterns between different taxa and sub-groups. Still, several of the reviewed papers indicate that time-lagged effects deserve more attention, especially on a landscape scale and for specialized or red-listed species. Further work is required before firm management recommendations can be suggested. © 2014 Springer Science+Business Media Dordrecht.

Comstedt D.,Örebro University | Bostrom B.,Örebro University | Ekblad A.,Swedish University of Agricultural Sciences
Biogeochemistry | Year: 2011

The two components of soil respiration, autotrophic respiration (from roots, mycorrhizal hyphae and associated microbes) and heterotrophic respiration (from decomposers), was separated in a root trenching experiment in a Norway spruce forest. In June 2003, cylinders (29.7 cm diameter) were inserted to 50 cm soil depth and respiration was measured both outside (control) and inside the trenched areas. The potential problems associated with the trenching treatment, increased decomposition of roots and ectomycorrhizal mycelia and changed soil moisture conditions, were handled by empirical modelling. The model was calibrated with respiration, moisture and temperature data of 2004 from the trenched plots as a training set. We estimate that over the first 5 months after the trenching, 45% of respiration from the trenched plots was an artefact of the treatment. Of this, 29% was a water difference effect and 16% resulted from root and mycelia decomposition. Autotrophic and heterotrophic respiration contributed to about 50% each of total soil respiration in the control plots averaged over the two growing seasons. We show that the potential problems with the trenching, decomposing roots and mycelia and soil moisture effects, can be handled by a modelling approach, which is an alternative to the sequential root harvesting technique. © 2010 Springer Science+Business Media B.V.

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