eKhSACIR інституційному репозитарії Харківської державної академії культури
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« INRA Feed Unit System for Ruminants », le nouveau “Livre Rouge” de l'INRA
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Oxidation of lignocelluloses by reactive oxygen species : chemical and enzymatic pathways
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A novel Zn(2)Cys(6) transcription factor BcGaaR regulates D-galacturonic acid utilization in Botrytis cinerea
No full textInternational audienceD-galacturonic acid (GalA) is the most abundant monosaccharide component of pectin. Previous transcriptome analysis in the plant pathogenic fungus Botrytis cinerea identified eight GalA-inducible genes involved in pectin decomposition, GalA transport and utilization. Co-expression of these genes indicates that a specific regulatory mechanism occurs in B. cinerea. In this study, promoter regions of these genes were analysed and eight conserved sequence motifs identified. The Bclga1 promoter, containing all these motifs, was functionally analysed and the motif designated GalA Responsive Element (GARE) was identified as the crucial cis-regulatory element in regulation of GalA utilization in B. cinerea. Yeast one-hybrid screening with the GARE motif led to identification of a novel Zn(2)Cys(6) transcription factor (TF), designated BcGaaR. Targeted knockout analysis revealed that BcGaaR is required for induction of GalA-inducible genes and growth of B. cinerea on GalA. A BcGaaR-GFP fusion protein was predominantly localized in nuclei in mycelium grown in GalA. Fluorescence in nuclei was much stronger in mycelium grown in GalA, as compared to fructose and glucose. This study provides the first report of a GalA-specific TF in filamentous fungi. Orthologs of BcGaaR are present in other ascomycete fungi that are able to utilize GalA, including Aspergillus spp., Trichoderma reesei and Neurospora crassa
Expression of Soluble Forms of Yeast Diacylglycerol Acyltransferase 2 That Integrate a Broad Range of Saturated Fatty Acids in Triacylglycerols
No full textInternational audienceThe membrane proteins acyl-CoA:diacylglycerol acyltransferases (DGAT) are essential actors for triglycerides (TG) biosynthesis in eukaryotic organisms. Microbial production of TG is of interest for producing biofuel and value-added novel oils. In the oleaginous yeast Yarrowia lipolytica, Dga1p enzyme from the DGAT2 family plays a major role in TG biosynthesis. Producing recombinant DGAT enzymes pure and catalytically active is difficult, hampering their detailed functional characterization. In this report, we expressed in Escherichia coli and purified two soluble and active forms of Y. lipolytica Dga1p as fusion proteins: the first one lacking the N-terminal hydrophilic segment (Dga1pDelta19), the second one also devoid of the N-terminal putative transmembrane domain (Dga1pDelta85). Most DGAT assays are performed on membrane fractions or microsomes, using radiolabeled substrates. We implemented a fluorescent assay in order to decipher the substrate specificity of purified Dga1p enzymes. Both enzyme versions prefer acyl-CoA saturated substrates to unsaturated ones. Dga1pDelta85 preferentially uses long-chain saturated substrates. Dga1p activities are inhibited by niacin, a specific DGAT2 inhibitor. The N-terminal transmembrane domain appears important, but not essential, for TG biosynthesis. The soluble and active proteins described here could be useful tools for future functional and structural studies in order to better understand and optimize DGAT enzymes for biotechnological applications
Landscape distribution of food and nesting sites affect larval diet and nest size, but not abundance of Osmia bicornis
No full textInternational audienceHabitat fragmentation is a major threat for beneficial organisms and the ecosystem services they provide. Multiple-habitat users such as wild bees depend on both nesting and foraging habitat. Thus, they may be affected by the fragmentation of at least two habitat types. We investigate the effects of landscape-scale amount of and patchisolation fromboth nesting habitat (woody plants) and foraging habitats (specific pollen sources) on the abundance and diet of Osmia bicornis L. Trap-nests of O. bicornis were studied in 30 agricultural landscapes of the Swiss Plateau. Nesting and foraging habitats were mapped in a radius of 500 m around the sites. Pollen composition of larval diet changed as isolation to the main pollen source, Ranunculus, increased, suggesting that O. bicornis adapted its foraging strategy in function of the nest proximity to mainpollensources.Abundance of O. bicornis was neither related to isolation or amount of nesting habitat nor to isolation or abundance of food plants. Surprisingly, nests of O. bicornis contained fewer larvae in sites at forest edge compared to isolated sites, possibly due to higher parasitism risk. This study indicates that O. bicornis can nest in a variety of situations by compensatingscarcity of its main larval food by exploiting alternative food sources
Carbon recovery dynamics following disturbance by selective logging in Amazonian forests
No full textWhen 2 Mha of Amazonian forests are disturbed by selective logging each year, more than 90 Tg of carbon (C) is emitted to the atmosphere. Emissions are then counterbalanced by forest regrowth. With an original modelling approach, calibrated on a network of 133 permanent forest plots (175 ha total) across Amazonia, we link regional differences in climate, soil and initial biomass with survivors' and recruits' C fluxes to provide Amazon-wide predictions of post-logging C recovery. We show that net aboveground C recovery over 10 years is higher in the Guiana Shield and in the west (21 +/- 3 Mg C ha(-1)) than in the south (12 +/- 3 Mg C ha(-1)) where environmental stress is high (low rainfall, high seasonality). We highlight the key role of survivors in the forest regrowth and elaborate a comprehensive map of post-disturbance C recovery potential in Amazonia
Biochem-Env, a plateform of environmental biochemistry for research
No full textInternational audienceAs a service of the research infrastructure AnaEE-France (http://www.anaee-france.fr/fr/), the platform Biochem-Env (http://www.biochemenv.fr) offers skills and innovative analytical tools for biochemical characterizations of soils, sediments, and micro-macro-organisms living in terrestrial and aquatic ecosystems. The platform provides methods validated according to Quality Guidelines, i.e. to measure global soil enzymatic activities. Our robot-supported protocols allow great number of enzyme measurements (hydrolase and oxidase activities) with high reproducibility. It has been involved in programs targeted at assessing the sensitivity and restrictions of biological indicators of soil quality, subjected to various constraints (waste landfilling, farming practices, contaminated sites and soils…). The platform is also at the origin of an ISO standard (ISO_TS_22939). Available as a scientific partner in the frame of collaborative research projects, the platform’s abilities ranges from advice providing (sampling, protocols and data analysis), to technical training, including analysis and experimentation in regional, national and international research programs
Interest and limits of a bovine MD chip to study <em>Bos taurus</em> × <em>Bos indicus</em> crossbred animals in India
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Managing the tradeoff between food production and ecosystem services: Optimizing land use allocation in temperate agro-landscapes
No full textNational audienceA major concern in environmental management is to satisfy an increasing food demand while preserving the provision of ecosystem services. In this study, we explore possible scenarios of land use allocation for managing the trade-off between food production and provision of multiple ecosystem services in France. We choose the Small Agricultural Region (SAR) as the smallest management unit for land use decisions. We calibrate empirical relationships estimating (i) agricultural and livestock production at the SAR level as a function of intensity and land use, (ii) ecosystem services provision as a function of land use. We explore scenarios of land use allocation and increased food production by (i) maximizing the provision of ecosystem services while putting constraint on food production and (ii) maximizing food production by putting constraints on the provision of ecosystem services. We also make considerations about two possible ways of managing the trade-off between food production and ecosystem services: by making each SAR multifunctional, allocating in it food production and the provision of ecosystem services (land sharing approach), or to allocate food production and the provision of ecosystem services in different mono-functional SARs (land sparing approach)