Skjanes K.,Bioforsk |
Skjanes K.,Uppsala University |
Pinto F.L.,Uppsala University |
Lindblad P.,Uppsala University
International Journal of Hydrogen Energy | Year: 2010
Some green algae have shown the ability to produce hydrogen under anaerobic conditions. The production of hydrogen in green algae is catalyzed by hydrogenases, which are small monomeric enzymes with high conversion efficiency and high oxygen sensitivity. Most green algae analyzed to date where hydrogenase genes are detected, have been shown to contain two distinct hydrogenases. However, very little is known about which functions the two different enzymes represent. There are also many unknowns within the mechanisms behind hydrogen production as to the roles hydrogenases play under different conditions, and consequently also about the potential for optimization of a hydrogen production process which could be found in this respect. This study focuses on the possibility for the presence of more than two hydrogenases in a single green alga. A large number of degenerate primers were designed and used to produce 3′-RACE products, which in turn were used to design gene specific primers used for PCR and 5′-RACE reactions. The sequences were aligned with known algal hydrogenases to identify products which had homology to these. Products where homology was identified were then explored further. A high number of clones from each band were sequenced to identify products with similar lengths which would not show up as separate bands on a gel. Sequences found to have homology with algal hydrogenases were translated into putative amino acid sequences and analyzed further to obtain detailed information about the presence of specific amino acids with known functions in the enzyme. This information was used to evaluate the likelihood of these transcripts coding for true hydrogenases, versus hydrogenase-like or narf-like proteins. We here present evidence showing that Chlamydomonas noctigama is able to transcribe three genes which share a significant number of characteristics with other known algal FeFe-hydrogenases. The three genes have been annotated HYDA1, HYDA2 and HYDA3. © 2009 Professor T. Nejat Veziroglu.
Acta Agriculturae Scandinavica A: Animal Sciences | Year: 2015
This literature review documents behavioural differences in organic and conventional sheep and goats in Norway. Increased indoor space results in increased lying time, more synchronized lying behaviour, less displacements and higher milk yield in sheep, and increased lying time and lower frequency of agonistic behaviour in goats. Sheep and goats spend 45–50% of their time outdoors when given access to an outdoor yard during winter. Under normal thermal conditions, fully fleeced sheep do not need solid floors of welfare reasons in Norway. Neither do dairy goats in insulated buildings. The significance of different milk feeding strategies in goat kids is poorly documented, but studies on lambs and calves show that suckling increases the growth rate, gives better social competence and more exploratory behaviour. Thus, the organic regulations in Norwegian sheep and goat production have some positive impact on behavioural indicators of sheep and goat welfare, especially during winter housing. © 2015 Taylor & Francis.
American Society of Agricultural and Biological Engineers Annual International Meeting 2013, ASABE 2013 | Year: 2013
Reference values and runoff coefficients are relevant to the implementation of The European Water Framework Directive, and data presented here could be of great value for further assessment of reference conditions in lakes and waters. In two JOVA-catchments, Skuterud and Volbu, runoff has been monitored runoff of nutrients and SS from smaller sub catchments with non-agricultural areas, mainly forested area or barren land. Data from these catchments, together with compiled data from other Norwegian studies of runoff from non-agricultural areas, are presented and discussed in this chapter. The concentrations of nitrogen (N) from forested areas in Skuterud are over twice as high as in Nyhagabrøtin. Annual losses of phosphorus (P) from forest field Nyhagabrøtin are in average 43 g total (T) P / ha with an increasing trend. The average P concentrations from Skuterud are 2.2 times higher than in Nyhagabrøtin. This may indicate a level of P losses around 95 g TP / ha. Annual average loss of suspended solids (SS) from Nyhagabrøtin is 13 kg SS/ha. These data helps to understand the complex variability of runoff depending on soil characteristics, precipitation and temperature.
Camsund D.,Uppsala University |
Heidorn T.,Bioforsk |
Lindblad P.,Uppsala University
Journal of Biological Engineering | Year: 2014
Background: Cyanobacteria are solar-powered prokaryotes useful for sustainable production of valuable molecules, but orthogonal and regulated promoters are lacking. The Lac repressor (LacI) from Escherichia coli is a well-studied transcription factor that is orthogonal to cyanobacteria and represses transcription by binding a primary lac operator (lacO), blocking RNA-polymerase. Repression can be enhanced through DNA-looping, when a LacI-tetramer binds two spatially separated lacO and loops the DNA. Ptrc is a commonly used LacI-repressed promoter that is inefficiently repressed in the cyanobacterium Synechocystis PCC 6803. Ptrc2O, a version of Ptrc with two lacO, is more efficiently repressed, indicating DNA-looping. To investigate the inefficient repression of Ptrc and cyanobacterial DNA-looping, we designed a Ptrc-derived promoter library consisting of single lacO promoters, including a version of Ptrc with a stronger lacO (Ptrc1O-proximal), and dual lacO promoters with varying inter-lacO distances (the Ptrc2O-library).Results: We first characterized artificial constitutive promoters and used one for engineering a LacI-expressing strain of Synechocystis. Using this strain, we observed that Ptrc1O-proximal is similar to Ptrc in being inefficiently repressed. Further, the Ptrc2O-library displays a periodic repression pattern that remains for both non- and induced conditions and decreases with longer inter-lacO distances, in both E. coli and Synechocystis. Repression of Ptrc2O-library promoters with operators out of phase is less efficient in Synechocystis than in E. coli, whereas repression of promoters with lacO in phase is efficient even under induced conditions in Synechocystis. Two well-repressed Ptrc2O promoters were highly active when tested in absence of LacI in Synechocystis.Conclusions: The artificial constitutive promoters herein characterized can be utilized for expression in cyanobacteria, as demonstrated for LacI. The inefficient repression of Ptrc and Ptrc1O-proximal in Synechocystis, as compared to E. coli, may be due to insufficient LacI expression, or differences in RNAP subunits. DNA-looping works as a transcriptional regulation mechanism similarly as in E. coli. DNA-looping contributes strongly to Ptrc2O-library repression in Synechocystis, even though they contain the weakly-repressed primary lacO of Ptrc1O-proximal and relatively low levels of LacI/cell. Hence, Synechocystis RNAP may be more sensitive to DNA-looping than E. coli RNAP, and/or the chromatin torsion resistance could be lower. Two strong and highly repressed Ptrc2O promoters could be used without induction, or together with an unstable LacI. © 2014 Camsund et al.; licensee BioMed Central Ltd.
Toth B.,University of Pannonia |
Weynants M.,European Commission - Joint Research Center Ispra |
Nemes A.,Bioforsk |
Mako A.,Hungarian Academy of Sciences |
And 2 more authors.
European Journal of Soil Science | Year: 2015
Summary: A range of continental-scale soil datasets exists in Europe with different spatial representation and based on different principles. We developed comprehensive pedotransfer functions (PTFs) for applications principally on spatial datasets with continental coverage. The PTF development included the prediction of soil water retention at various matric potentials and prediction of parameters to characterize soil moisture retention and the hydraulic conductivity curve (MRC and HCC) of European soils. We developed PTFs with a hierarchical approach, determined by the input requirements. The PTFs were derived by using three statistical methods: (i) linear regression where there were quantitative input variables, (ii) a regression tree for qualitative, quantitative and mixed types of information and (iii) mean statistics of developer-defined soil groups (class PTF) when only qualitative input parameters were available. Data of the recently established European Hydropedological Data Inventory (EU-HYDI), which holds the most comprehensive geographical and thematic coverage of hydro-pedological data in Europe, were used to train and test the PTFs. The applied modelling techniques and the EU-HYDI allowed the development of hydraulic PTFs that are more reliable and applicable for a greater variety of input parameters than those previously available for Europe. Therefore the new set of PTFs offers tailored advanced tools for a wide range of applications in the continent. Z © 2014 The Authors. European Journal of Soil Science published by John Wiley & Sons Ltd on behalf of British Society of Soil Science.