Universitatstrasse 16

Zürich, Switzerland

Universitatstrasse 16

Zürich, Switzerland
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Sanchez D.H.,Max Planck Institute of Molecular Plant Physiology | Sanchez D.H.,University of Geneva | Schwabe F.,Max Planck Institute of Molecular Plant Physiology | Schwabe F.,Universitatstrasse 16 | And 3 more authors.
Plant, Cell and Environment | Year: 2012

Water limitation has become a major concern for agriculture. Such constraints reinforce the urgent need to understand mechanisms by which plants cope with water deprivation. We used a non-targeted metabolomic approach to explore plastic systems responses to non-lethal drought in model and forage legume species of the Lotus genus. In the model legume Lotus.japonicus, increased water stress caused gradual increases of most of the soluble small molecules profiled, reflecting a global and progressive reprogramming of metabolic pathways. The comparative metabolomic approach between Lotus species revealed conserved and unique metabolic responses to drought stress. Importantly, only few drought-responsive metabolites were conserved among all species. Thus we highlight a potential impediment to translational approaches that aim to engineer traits linked to the accumulation of compatible solutes. Finally, a broad comparison of the metabolic changes elicited by drought and salt acclimation revealed partial conservation of these metabolic stress responses within each of the Lotus species, but only few salt- and drought-responsive metabolites were shared between all. The implications of these results are discussed with regard to the current insights into legume water stress physiology. The study 'Comparative metabolomics of drought acclimation in model and forage legumes' aims for an enhanced understanding of legume drought acclimation mechanisms, specifically the potential function of complex metabolic acclimation patterns in the Lotus genus. Using non-targeted GC-MS based metabolite profiling technologies we compared the plastic systems responses to non-lethal water limitation in model and forage legume species. As was observed for other stress cues, increased water stress caused gradual metabolic changes which reflected a global and progressive reprogramming of metabolic pathways. The metabolomic analysis includes a comparison of the drought responses to previously reported salt stress responses of the same Lotus species. Our study revealed conserved and unique metabolic responses to drought stress. Importantly, only few drought responsive metabolites were conserved among all species. Thus we highlight a potential impediment to translational approaches that aim to engineer traits linked to the accumulation of compatible solutes. The implications of these results are discussed with regard to the current insights into legume water stress physiology. © 2011 Blackwell Publishing Ltd.

Kremer A.,French National Institute for Agricultural Research | Kremer A.,University of Bordeaux 1 | Ronce O.,Montpellier University | Robledo-Arnuncio J.J.,Forest Research Center | And 11 more authors.
Ecology Letters | Year: 2012

Forest trees are the dominant species in many parts of the world and predicting how they might respond to climate change is a vital global concern. Trees are capable of long-distance gene flow, which can promote adaptive evolution in novel environments by increasing genetic variation for fitness. It is unclear, however, if this can compensate for maladaptive effects of gene flow and for the long-generation times of trees. We critically review data on the extent of long-distance gene flow and summarise theory that allows us to predict evolutionary responses of trees to climate change. Estimates of long-distance gene flow based both on direct observations and on genetic methods provide evidence that genes can move over spatial scales larger than habitat shifts predicted under climate change within one generation. Both theoretical and empirical data suggest that the positive effects of gene flow on adaptation may dominate in many instances. The balance of positive to negative consequences of gene flow may, however, differ for leading edge, core and rear sections of forest distributions. We propose future experimental and theoretical research that would better integrate dispersal biology with evolutionary quantitative genetics and improve predictions of tree responses to climate change. © 2012 Blackwell Publishing Ltd/CNRS.

Jokela J.,Eawag - Swiss Federal Institute of Aquatic Science and Technology | Jokela J.,Universitatstrasse 16
Journal of Animal Ecology | Year: 2010

Eggs are relatively large and can provide offspring with resources that improve their survival. While such maternal effects are common, it has been difficult to imagine what, other than genes, individual offspring could receive from their fathers. The study by Roth et al. (2009a) suggests that we should look more closely. Their experiments show that red flour beetle fathers can transfer specific biochemical information to their offspring, priming their immune system to combat pathogens better. When mothers do the same, the offspring get a double dose of protection. This discovery alerts us to re-evaluate the importance of cryptic parental care. ©2009 The Authors. Journal compilation ©2009 British Ecological Society.

Parrish D.D.,National Oceanic and Atmospheric Administration | Law K.S.,University of Versailles | Staehelin J.,Universitatstrasse 16 | Derwent R.,Rdscientific | And 8 more authors.
Geophysical Research Letters | Year: 2013

At northern midlatitudes the abundance of tropospheric O3 has increased by a factor of approximately 2 since the 1950s. The cause of this increase is generally attributed to increasing anthropogenic precursor emissions, but present chemical and transport models cannot quantitatively reproduce its magnitude. Here we show another manifestation of changes in O 3 abundance - a shift of the seasonal cycle at northern midlatitudes so that the observed peak concentrations now appear earlier in the year than in previous decades. The rate of this shift has been 3 to 6 days per decade since the 1970s. We examine possible reasons to explain this shift and suggest it is due to changes in atmospheric transport patterns combined with spatial and temporal changes in emissions. Detailed modeling is necessary to test these hypotheses; this investigation will provide useful guidance for improving global chemistry-climate models and stringent tests of the model results. Key Points The date of the maximum of tropospheric ozone has moved to earlier in the year Change has been approximately constant at 3 to 6 days per decade since the 1970s Cause of change may be due to changing climate and/or anthropogenic emissions. ©2013. American Geophysical Union. All Rights Reserved.

Parrish D.D.,National Oceanic and Atmospheric Administration | Law K.S.,University of Versailles | Staehelin J.,Universitatstrasse 16 | Derwent R.,Rdscientific | And 8 more authors.
Atmospheric Chemistry and Physics | Year: 2012

Changes in baseline (here understood as representative of continental to hemispheric scales) tropospheric O3 concentrations that have occurred at northern mid-latitudes over the past six decades are quantified from available measurement records with the goal of providing benchmarks to which retrospective model calculations of the global O3 distribution can be compared. Eleven data sets (ten ground-based and one airborne) including six European (beginning in the 1950's and before), three North American (beginning in 1984) and two Asian (beginning in 1991) are analyzed. When the full time periods of the data records are considered a consistent picture emerges; O3 has increased at all sites in all seasons at approximately 1% yr-1 relative to the site's 2000 yr mixing ratio in each season. For perspective, this rate of increase sustained from 1950 to 2000 corresponds to an approximate doubling. There is little if any evidence for statistically significant differences in average rates of increase among the sites, regardless of varying length of data records. At most sites (most definitively at the European sites) the rate of increase has slowed over the last decade (possibly longer), to the extent that at present O3 is decreasing at some sites in some seasons, particularly in summer. The average rate of increase before 2000 shows significant seasonal differences (1.08 ± 0.09, 0.89 ± 0.10, 0.85 ± 0.11 and 1.21 ± 0.12% yr-1 in spring, summer, autumn and winter, respectively, over North America and Europe). © 2012 Author(s). CC Attribution 3.0 License.

Dauth A.,University of British Columbia | Rigling C.,Universitatstrasse 16 | Tsoung J.,University of Toronto | Love J.A.,University of British Columbia
Chemistry - A European Journal | Year: 2013

The preparation of substituted oxa-and azarhodacyclobutanes is reported. After exchange of ethylene with a variety of unsymmetrically and symmetrically substituted alkenes, the corresponding rhodium-olefin complexes were oxidized with H2O2 and PhINTs (Ts=p-toluenesulfonyl) to yield the substituted oxa-and azarhodacyclobutanes, respectively. Oxarhodacyclobutanes could be prepared with excellent selectivity for incorporation of the oxygen atom on the more substituted carbon atom of the alkene. At the same time, azarhodacyclobutanes showed good-to-excellent selectivity for heteroatom incorporation on the less substituted carbon. Furthermore, it was shown that steric modifications of the ancillary ligand have a significant influence on the selectivity of Rh-olefin complex formation as well as formation of the substituted azametallacycles. Substitute(d) players: The oxidation of a variety of rhodium complexes bearing substituted olefin ligands by H2O 2 and PhINTs is reported. The resulting oxa-and azarhodacyclobutanes are obtained with good-to-excellent regioselectivity (see scheme; Ts=p-toluenesulfonyl). Notably, complementary selectivity for heteroatom incorporation was observed depending on the oxidant employed. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mooers A.,Simon Fraser University | Gascuel O.,Montpellier University | Stadler T.,Universitatstrasse 16 | Li H.,University of Canterbury | Steel M.,University of Canterbury
Systematic Biology | Year: 2012

Diversification is nested, and early models suggested this could lead to a great deal of evolutionary redundancy in the Tree of Life. This result is based on a particular set of branch lengths produced by the common coalescent, where pendant branches leading to tips can be very short compared with branches deeper in the tree. Here, we analyze alternative and more realistic Yule and birth-death models. We show how censoring at the present both makes average branches one half what we might expect and makes pendant and interior branches roughly equal in length. Although dependent on whether we condition on the size of the tree, its age, or both, these results hold both for the Yule model and for birth-death models with moderate extinction. Importantly, the rough equivalency in interior and exterior branch lengths means that the loss of evolutionary history with loss of species can be roughly linear. Under these models, the Tree of Life may offer limited redundancy in the face of ongoing species loss. © 2011 The Author(s).

Cisarovsky G.,Universitatstrasse 16 | Schmid-Hempel P.,Universitatstrasse 16
Entomologia Experimentalis et Applicata | Year: 2014

Knowledge of the complete life cycle of a parasite is crucial to understand the epidemiology and population dynamics of a disease. The populations of several social insect pollinators are decreasing, and parasites are often cited as a contributing factor. The exact transmission pathway of the bumblebee parasite Crithidia bombi (Lipa & Triggiani) (Kinetoplastea: Trypanosomatidae) between two hosts is still unknown, although a previous laboratory experiment suggests transmission via the nectar of flowers. Plant species may differentially protect or negatively affect the parasite while it resides in the flower, for instance if plants vary in their floral shape or the compounds present in their nectar. This will lead to differential transmission success and potentially influence disease epidemiology. In the present study we aimed at determining whether the parasite may indeed be transmitted in the nectar by the bumblebee Bombus terrestris (L.) (Hymenoptera: Apidae).We found that parasite survival was significantly decreased in water with higher sugar concentrations. However, none of the field-collected nectar samples contained parasite cells, and no parasite cells were transmitted between two artificial flowers by a foraging worker under laboratory conditions. Our results suggest instead that parasite cellsmay be deposited on flower surfaces and transported on worker surfaces. © 2014 The Netherlands Entomological Society.

Zimmermann W.,Universitatstrasse 16
Schweizerische Zeitschrift fur Forstwesen | Year: 2013

Swiss national forest policy in 2012 was marked by the enactment of the revised Forest Law as well as preparations for the changes in the related Forest Ordinance. No new directions have emerged in the routine forest relevant tasks of the Parliament, Federal Council and the Public Administration. Exceptions to this trend were the numerous parliamentary interventions about the forest and timber industry. In addition, the number of Federal Court decisions about forest legal issues has slightly increased this year. In the policy fields related to forest policy, the passage of the Second Apartment Initiative and the revision of the Land-Use Law brought new angles into land-use policy. In terms of biodiversity policy, the Federal Council's approval of the Biodiversity Strategy Switzerland has set the stage for its implementation. Finally, the reorganization of Swiss energy policy has become the new dominant topic on the political agenda. The Federal Council has accomplished the related preparations for the new energy policy and has submitted its Energy Strategy 2050 for consultation.

Ashton P.,Harvard University | Kettle C.J.,Universitatstrasse 16
Biotropica | Year: 2012

The dipterocarps are dominant trees across a large part of lowland Southeast Asia. These forests provide a valuable timber resource, are rich in biodiversity, and are among the most important terrestrial carbon sinks in the world. Yet, these forests are fast disappearing, often unsustainably managed and are rapidly being replaced by agricultural crops such as oil palm and other commercial plantations. Here, we provide a brief overview to this family, outline its significance, and introduce the articles of this Special Section which provides a collection of the recent advances in our understanding of the biology of this important family of tropical trees. © 2012 The Author(s) Journal compilation © 2012 by The Association for Tropical Biology and Conservation.

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