15 research outputs found
Conseil à l'officine face à une éruption vésiculo-bulleuse
PARIS-BIUP (751062107) / SudocSudocFranceF
Highlighting of quorum sensing lux genes and their expression in the hydrothermal vent shrimp Rimicaris exoculata ectosymbiontic community. Possible use as biogeographic markers.
Rimicaris exoculata is a caridean shrimp that dominates the fauna at several hydrothermal vent sites of the Mid-Atlantic Ridge. It has two distinct and stable microbial communities. One of these epibiontic bacterial communities is located in the shrimp gut and has a distribution and role that are poorly understood. The second colonizes its enlarged gill chamber and is involved in host nutrition. It is eliminated after each molt, and has colonization processes reminiscent of those of a biofilm. The presence and expression of genes usually involved in quorum sensing (QS) were then studied. At four sites, Rainbow, TAG, Snake Pit and Logatchev, two lux genes were identified in the R. exoculata epibiontic community at different shrimp molt stages and life stages. RT-PCR experiments highlighted lux gene expression activity at TAG, Snake Pit and Rainbow vent sites. Their potential QS activity and their possible roles in epibiont colonization processes are discussed. Moreover, phylogenetic analysis has shown the presence of three clades for luxS (Epsilonproteobacteria) and four clades for luxR (Gammaproteobacteria) genes, each clade being restricted to a single site. These genes are more divergent than the 16S rRNA one. They could therefore be used as biogeographical genetic markers
Les carnets aujourdâhui
Petit objet nomade Ă lâapparence souvent anodine, le carnet a dĂ©voilĂ© au fil du temps ses nombreuses potentialitĂ©s matĂ©rielles et crĂ©atives, exploitĂ©es autant par les Ă©crivains que les scientifiques, autant par les artistes que les thĂ©oriciens. Lâexploration de ces potentialitĂ©s en contexte dâapprentissage ou de formation rĂ©unit, depuis 2012, des chercheurs et des enseignants Ă lâĂ©cole supĂ©rieure du professorat et de lâĂ©ducation (ESPE) de lâuniversitĂ© de Caen Normandie. Leurs Ă©changes et leurs rĂ©flexions ont fait Ă©merger trois dimensions clĂ©s du carnet : la construction dâun sujet lecteur / scripteur Ă partir de carnets de lecture ou dâĂ©criture, lâapprentissage (inter)disciplinaire facilitĂ© par lâutilisation du carnet en classe, et enfin les liens complexes qui se tissent entre carnet, mobilitĂ© et interculturalitĂ©. De maniĂšre inĂ©dite, cet ouvrage croise les regards sur lâobjet carnet en proposant des dispositifs institutionnels, des recherches acadĂ©miques, anthropologiques et didactiques, mais aussi des comptes rendus dâexpĂ©riences sur le terrain, en classe comme en formation