Premiers résultats de validation des classes de pédotransfert établies à partir de la base de données SOLHYDRO 1.0. Application à des sols de la région Centre

National audienceLes propriétés de rétention en eau de 42 horizons appartenant à 11 sols de la Région Centre ont été mesurées pour 7 valeurs de potentiel. Les teneurs en eau volumiques ainsi déterminées ont été comparées à celles obtenues en utilisant des classes de pédotransfert (CPT) établies à partir de la base de données SOLHYDRO 1.0. Ces classes de pédotransfert utilisent soit seulement le type d’horizon et la texture (CPT texturales), soit le type d’horizon, la texture et la densité apparente de l’horizon (CPT texturo-structurales). Avec les CPT texturales, les teneurs en eau sont en moyenne légèrement surestimées (0,7 % en teneur en eau volumique). La prise en compte de la structure des horizons grâce à leur densité apparente (CPT texturo-structurales) ne réduit pas ce biais de prédiction. La précision obtenue avec les CPT texturales ou texturo-structurales est en moyenne voisine de 3 % en teneur en eau volumique. Une amélioration de la précision est enregistrée pour les horizons E, B et C et pour ceux de texture argileuse lorsque l’on passe des CPT texturales aux CPT texturo-structurales. Ainsi, sur la base de ces premiers résultats de validation, il apparaît que l’utilisation des CPT texturo-structurales n’apporte une amélioration sensible de la qualité de la prédiction (augmentation de la précision) que pour les horizons E, B ou C et les horizons de texture ALO, AS, A ou AL. Dans les autres horizons appartenant à des sols apparentés aux sols étudiés, il apparaît justifié de se limiter à l’utilisation des CPT texturales puisque la prise en compte de la densité apparente n’améliore au mieux que très peu le biais et la précision des prédictions

Dynamic sediment profile imaging (DySPI): a new field method for the study of dynamic processes at the sediment-water interface

International audienceSediment transport processes at the sediment-water interface are usually studied using flume tests. Due to technical limitations, extreme hydro-sedimentary conditions are then rarely considered. Sediment profile imaging (SPI) is a widely used technique for mapping benthic habitat quality in soft sediments but several limitations exist that make the system ineffective for coarse or indurate sediment investigations and for transport processes studies. To address this problem, a modified system was designed to investigate these processes in situ, on a grain-size scale, with high temporal resolution. A dynamic sediment profile imaging (DySPI) system was constructed with a new mode of penetration, an appropriate design and an imaging system based on high-definition video recording. The supporting frame was instrumented with autonomous sensors to monitor boundary layer characteristics along with video observations. This system was deployed during spring tide on sediment characterized by a mixture of particle sizes dominated by coarse grains. Appropriate image processing allowed determination of the area of sediment entrained, movement threshold, size of moving particles, instantaneous transport rate and interface profile changes, in addition to usual SPI parameters. However, DySPI is a prototype and further development of the instrument and the image processing are possible to enlarge the scope presented in this study

Tempo-Mini: A Custom-designed instrument for real-time monitpring of hydrothermal vent ecosystems

TEMPO-Mini is a new custom-designed instrument package created by IFREMER for real-time monitoring of hydrothermal faunal assemblages

Tempo-Mini: A Custom-designed instrument for real-time monitpring of hydrothermal vent ecosystems

TEMPO-Mini is a new custom-designed instrument package created by IFREMER for real-time monitoring of hydrothermal faunal assemblages.Peer Reviewe

Tempo-Mini: A Custom-designed instrument for real-time monitpring of hydrothermal vent ecosystems

TEMPO-Mini is a new custom-designed instrument package created by IFREMER for real-time monitoring of hydrothermal faunal assemblages.Peer Reviewe

Inhibition of the pseudokinase MLKL alters extracellular vesicle release and reduces tumor growth in glioblastoma

International audienceExtracellular vesicles (EVs) are lipid-based nanosized particles that convey biological material from donor to recipient cells. EVs play key roles in glioblastoma progression because glioblastoma stem-like cells (GSCs) release pro-oncogenic, proangiogenic, and pro inflammatory EVs. However, the molecular basis of EV release remains poorly understood. Here, we report the identification of the pseudokinase MLKL, a crucial effector of cell death by necroptosis, as a regulator of the constitutive secretion of EVs in GSCs. We find that genetic, protein, and pharmacological targeting of MLKL alters intracellular trafficking and EV release, and reduces GSC expansion. Nevertheless, this function ascribed to MLKL appears independent of its role during necroptosis. In vivo, pharmacological inhibition of MLKL reduces the tumor burden and the level of plasmatic EVs. This work highlights the necroptosis-independent role of MLKL in vesicle release and suggests that interfering with EVs is a promising therapeutic option to sensitize glioblastoma cells

Estrogen-mediated downregulation of AIRE influences sexual dimorphism in autoimmune diseases.

International audienceAutoimmune diseases affect 5% to 8% of the population, and females are more susceptible to these diseases than males. Here, we analyzed human thymic transcriptome and revealed sex-associated differences in the expression of tissue-specific antigens that are controlled by the autoimmune regulator (AIRE), a key factor in central tolerance. We hypothesized that the level of AIRE is linked to sexual dimorphism susceptibility to autoimmune diseases. In human and mouse thymus, females expressed less AIRE (mRNA and protein) than males after puberty. These results were confirmed in purified murine thymic epithelial cells (TECs). We also demonstrated that AIRE expression is related to sexual hormones, as male castration decreased AIRE thymic expression and estrogen receptor α-deficient mice did not show a sex disparity for AIRE expression. Moreover, estrogen treatment resulted in downregulation of AIRE expression in cultured human TECs, human thymic tissue grafted to immunodeficient mice, and murine fetal thymus organ cultures. AIRE levels in human thymus grafted in immunodeficient mice depended upon the sex of the recipient. Estrogen also upregulated the number of methylated CpG sites in the AIRE promoter. Together, our results indicate that in females, estrogen induces epigenetic changes in the AIRE gene, leading to reduced AIRE expression under a threshold that increases female susceptibility to autoimmune diseases