Light-driven processes: key players of the functional biodiversity in microalgae

International audienc

De "nouvelles" souches du virus des ailes déformées (DWV) chez l'abeille ?

National audienc

De "nouvelles" souches du virus des ailes déformées (DWV) chez l'abeille ?

National audienc

RésApi, un réseau prototype de ruchers ateliers pour comprendre les pertes hivernales de colonies: résultats préliminaires de la campagne 2012-2013

National audienc

Proteomics unveil a central role for peroxisomes in butyrate assimilation of the heterotrophic Chlorophyte alga Polytomella sp.

Volatile fatty acids found in effluents of the dark fermentation of biowastes can be used for mixotrophic growth of microalgae, improving productivity and reducing the cost of the feedstock. Microalgae can use the acetate in the effluents very well, but butyrate is poorly assimilated and can inhibit growth above 1 gC.L−1. The non-photosynthetic chlorophyte alga Polytomella sp. SAG 198.80 was found to be able to assimilate butyrate fast. To decipher the metabolic pathways implicated in butyrate assimilation, quantitative proteomics study was developed comparing Polytomella sp. cells grown on acetate and butyrate at 1 gC.L−1. After statistical analysis, a total of 1772 proteins were retained, of which 119 proteins were found to be overaccumulated on butyrate vs. only 46 on acetate, indicating that butyrate assimilation necessitates additional metabolic steps. The data show that butyrate assimilation occurs in the peroxisome via the β-oxidation pathway to produce acetyl-CoA and further tri/dicarboxylic acids in the glyoxylate cycle. Concomitantly, reactive oxygen species defense enzymes as well as the branched amino acid degradation pathway were strongly induced. Although no clear dedicated butyrate transport mechanism could be inferred, several membrane transporters induced on butyrate are identified as potential condidates. Metabolic responses correspond globally to the increased needs for central cofactors NAD, ATP and CoA, especially in the peroxisome and the cytosol

Proteomics unveil a central role for peroxisomes in butyrate assimilation of the heterotrophic Chlorophyte alga Polytomella sp

Volatile fatty acids found in effluents of the dark fermentation of biowastes can be used for mixotrophic growth of microalgae, improving productivity and reducing the cost of the feedstock. Microalgae can use the acetate in the effluents very well, but butyrate is poorly assimilated and can inhibit growth above 1 gC.L -1 . The non-photosynthetic chlorophyte alga Polytomella sp. SAG 198.80 was found to be able to assimilate butyrate fast. To decipher the metabolic pathways implicated in butyrate assimilation, quantitative proteomics study was developed comparing Polytomella sp. cells grown on acetate and butyrate at 1 gC.L -1 . After statistical analysis, a total of 1772 proteins were retained, of which 119 proteins were found to be overaccumulated on butyrate vs. only 46 on acetate, indicating that butyrate assimilation necessitates additional metabolic steps. The data show that butyrate assimilation occurs in the peroxisome via the β-oxidation pathway to produce acetyl-CoA and further tri/dicarboxylic acids in the glyoxylate cycle. Concomitantly, reactive oxygen species defense enzymes as well as the branched amino acid degradation pathway were strongly induced.Although no clear dedicated butyrate transport mechanism could be inferred, several membrane transporters induced on butyrate are identified as potential condidates. Metabolic responses correspond globally to the increased needs for central cofactors NAD, ATP and CoA, especially in the peroxisome and the cytosol

Survie d'abeilles à Varroa

National audienc

Varroa : son impact, les méthodes d’évaluation de l’infestation et les moyens de lutte

Le parasite de l’abeille Varroa destructor est actuellement considéré comme une menace pathogène majeure pour l’abeille domestique. De prévalence mondiale, il est responsable de nombreux dommages à l’échelle individuelle et de la colonie, notamment du fait de l’association du parasite avec plusieurs virus de l’abeille. Les travaux conduits au sein de l’UMT PrADE ont permis de caractériser certains effets du parasitisme sur la physiologie des abeilles, ainsi que de mieux comprendre l’association entre le varroa et les virus de l’abeille. Plusieurs techniques ont été développées ou validées afin de pouvoir suivre l’évolution de la charge parasitaire au cours d’une saison apicole. Enfin, des essais ont été réalisés pour évaluer l’efficacité des traitements de fin de saison et tester de nouvelles stratégies de traitement (en saison et fin de saison). Plusieurs études se concentrent actuellement autour de la perspective d’utiliser la sélection d’abeilles naturellement résistantes au varroa comme stratégie de lutte durable contre le parasite.The honey bee parasite Varroa destructor is currently considered as the main pathogenic threat of honey bee colonies. It is distributed worldwide and responsible for many negative effects on bees, both at the individual and colony levels. The pathogenicity of varroa is strengthened by the association of the mite with several honey bee viruses. Work conducted by the UMT PrADE as lead to characterising some effects of parasitisation on honey bee physiology, as well as to better understand the association between varroa and bee viruses. Several techniques have been developed or validated in order to survey the evolution of parasite loads along the beekeeping season. F. Mondet et al. 64 Innovations Agronomiques 53 (2016), 63-80 Assays have been run to assess the efficacy of end-of-season treatments and to test new treatment strategies (during the season and at the end of the season). Studies currently focus on the possibility to use the selection of naturally varroa resistant bees as a sustainable solution to fight the mite

Evolution du virus des ailes déformées (Deformed wing virus, DWV)

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