Morphology and ecology of Craticula lecohui sp. nov. (Bacillariophyceae) from hydrothermal springs (Puy-de-Dôme, Massif Central, France) and comparison with similar Craticula species

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The distribution of macroinvertebrate assemblages in a reach of the River Allier (France), in relation to riverbed characteristics

International audienceMacroinvertebrate assemblages of large alluvial streams are poorly documented. This study identified the physical characteristics affecting the macroinvertebrates community distribution in a large alluvial river devoid of major anthropogenic impacts. It was oriented towards the influence of the characteristics of the physical habitat (velocity, depth, grain-size classes of mineral substrates, macrophytes) on macroinvertebrates (richness, density, body size, feeding habits), with particular attention to the pollution-sensitive taxa. The study was carried out in June during a period of hydrological stability. The effects of water velocity, depth and substrates on taxa were evaluated with multivariate analyses. Mineral substrates were most abundant while macrophytes accounted for only 3% of sampled habitat. Invertebrates that were present were those characteristics of the transition zone between upper and middle life reaches. Among the 63 taxa sampled, 14 were abundant. In relation to the characteristics of the physical environment, the macroinvertebrate assemblages were discriminated by substrate, velocity, and depth. Habitat exploitation, however, appeared complex. The highest community richness, EPT richness, and density were found in various substrates where the velocity ranged between 30 and 120 cm s)1, depths ranged from 16 to 50 cm. The most pollution-sensitive taxa preferred riffle habitats with velocities >70 cm s)1 and substrate >64 mm. This suggest that rapid bioassessment programmes should be carried out in the mineral substrates of the geomorphological unit riffles where richness is high and density sufficient to represent the macroinvertebrate community, including pollution-sensitive taxa

L’épave du Veurdre: Un exemple de bateau de rivière d’époque moderne

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Nafion®-sepiolite composite membranes for improved Proton Exchange Membrane Fuel Cell performance.

Nafion®-sepiolite composite membranes were prepared, characterized and integrated in Membrane-Electrodes Assembly to be tested in fuel cell operating conditions. The influence of the sepiolite content and its modification on the membrane properties was carefully analyzed. The performances of the different MEAs were compared at different operating temperatures and under various relative humidity. The sulfonation of pristine sepiolite has improved its ion exchange capacity as well as that of composites membranes. The introduction of sepiolite in Nafion ® also allowed simultaneously to increase its water uptake and to improve its mechanical features. Much better performances were obtained at high temperature and low relative humidity with MEAs based upon Nafion®-sepiolite composite membranes compared to pure Nafion ® membranes (50 % more output power at 100 °C and 50 %RH)

Sexual dimorphism of hepatic epigenetic marks and machinery in offspring of obese and diabetic mothers fed a control diet during periconceptional/gestation/lactation period

National audienceEarly nutritional events may have an influence on later life health mainly through epigenetic processes.1 In our two- generation mice model, providing obese and diabetic mice with a control diet during the periconceptional/gestation/ lactation period led to a pronounced sex-specific shift from susceptibility to resistance to a high-fat diet (HFD) in the female offspring only.2,3 The aim of this study was to detect sex-specific differences in the expression of candidate genes and epigenetic marks and machinery in the liver of both sexes and both generations. As a key organ for lipid processing and detoxification, liver plays a major role in conditions of chronic lipid oversupply. According to the sex, female (F) or male (M), the generation, first (F1) or second (F2), and diet types, CD or HFD, mice were divided into eight groups (F-F1-CD, F-F1-HFD, M-F1-CD, M-F1-HFD, F-F2-CD, F-F2-HFD, M-F2-CD and M-F2-HFD). Body weight, blood glucose level and blood cholesterol levels were measured. Liver morphology was identified by hematoxylin–eosin staining and oil red O staining. Hepatosteatosis was found to be more common in all HFD groups with adaptation of the liver phenotype in F2 females but not in males, in parallel with obesity and cholesterol levels.4 Global DNA methyla- tion and histone modifications were investigated by LUMA and Western blot analysis, respectively. Interestingly, although no significant difference was found within groups, global DNA methylation level was significantly negatively correlated to steatosis percentage. Using RT-qPCR, sexual dimorphism was observed for the gene expression of 12 genes encoding enzymes of the epigenetic machinery. These marks may help us to understand the sex-specific epigenetic mechanisms of the underlying sex-specific responses to HFD and improve the early life nutritional environment in a sex-specific manner. The author(s) declare that they have no competing interests