Stéphane Gros, La Part manquante: Échanges et pouvoirs chez les Drung du Yunnan (The missing share: Exchange and power among the Drung of Yunnan),

The Drung, or Dulong, are a social group of a few thousand people living mainly in the Dulong River valley of Southwest China at the frontiers of Myanmar and Tibet. There are still a few elderly Drung women alive today whose faces were tattooed when they were girls, and for the Chinese, photographs of these tattoos have come to symbolise the “savage” and “exotic” (p. 42) character of the remote borderlands of Yunnan Province. Until the 1960s, the valley did not have a road connecting it to th..

Characterization and corrosion behaviour of grade 2 titanium used in electrolyzers for hydrogen production

The decentralized production of hydrogen as a renewable energy vector targets large markets and potential applications: mobility, electricity and fixed heat generation, electricity storage in the form of gas. Hydrogen is today in France and in the industrialized countries an emerging industrial sector, leading to an increasing development of electrolyzers. The study of the behaviour of grade 2 titanium used in these electrolyzers for hydrogen production, using a characterization of parts by Scanning Electron Microscopy (SEM), surface analysis by Glow Discharge Optical Emission Spectrometry (GDOES) demonstrating the hydrogen diffusion in titanium, and electrochemical measurements, will make it possible to understand and interpret the mechanisms that caused degradation after 5000 h of operation and to validate the choice of grade 2 titanium

Stéphane Gros, La Part manquante: Échanges et pouvoirs chez les Drung du Yunnan,

Les Drung, ou Dulong, forment un groupe social de quelques milliers d’individus vivant principalement dans la vallée de la rivière Dulong au sud-ouest de la Chine à la frontière avec la Birmanie et le Tibet. Parmi eux survivent encore quelques femmes âgées dont les visages ont été tatoués quand elles étaient encore jeunes filles. Pour les Chinois, les photographies de ces tatouages en sont venus à symboliser le caractère « sauvage » et « exotique » (p. 42) des lointaines régions frontalières ..

Stéphane Gros, La Part manquante: Échanges et pouvoirs chez les Drung du Yunnan (The missing share: Exchange and power among the Drung of Yunnan),

The Drung, or Dulong, are a social group of a few thousand people living mainly in the Dulong River valley of Southwest China at the frontiers of Myanmar and Tibet. There are still a few elderly Drung women alive today whose faces were tattooed when they were girls, and for the Chinese, photographs of these tattoos have come to symbolise the “savage” and “exotic” (p. 42) character of the remote borderlands of Yunnan Province. Until the 1960s, the valley did not have a road connecting it to th..

Rôle de la protéine de la signalisation du calcium CML8 dans la réponse d'Arabidopsis thaliana à de multiples stress : implication dans l'immunité contre plusieurs pathogènes et importance de l'auxine

Le calcium est un second messager universel impliqué dans l'adaptation des plantes aux changements de l'environnement. Les variations de concentration de calcium dans la cellule végétale sont décodées et relayées par des protéines senseurs de calcium. Parmi ces protéines, on retrouve les CMLs ou protéines "Calmoduline-Like". Au cours de ma thèse, nous avons identifié que CML8 participe aux réponses immunitaires de la plante face à de multiples microorganismes pathogènes dont la bactérie du sol Ralstonia solanacearum capable d'infecter plus de 200 espèces de plantes (Arabidopsis thaliana, tomate, banane), la bactérie foliaire Xanthomonas campestris pv. campestris et l'oomycète racinaire Phytophtora capsici. Mon projet de thèse a eu pour objectif de préciser la fonction de CML8 pour comprendre son rôle dans l'immunité végétale, et plus précisément dans la réponse de défense de la plante Arabidopsis thaliana à Ralstonia solanacearum. Pour cela, une approche de transcriptomique par RNA-sequencing a permis d'identifier les mécanismes moléculaires dépendants de CML8 en réponse à une infection par Ralstonia solanacearum. Également, CML8 est exprimé préférentiellement au niveau de l'émergence des racines latérales et contrôle l'architecture racinaire de manière auxine-dépendante. Ces émergences sont le lieu d'accumulation de l'auxine endogène de la plante mais également le point d'entrée de Ralstonia solanacearum dans la plante. Sachant cela et sachant aussi que le séquençage du génome de Ralstonia solanacearum a montré qu'il était possible que cette bactérie puisse synthétiser de l'auxine, nous avons choisi d'étudier les processus d'infection de Ralstonia solanacearum en cherchant à identifier la ou les voies de biosynthèse putatives de l'auxine chez Ralstonia solanacearum pour déterminer le rôle de l'auxine produite par la bactérie au cours de l'interaction avec la plante.Calcium is a universal second messenger involved in the adaptation of plants to environmental changes. Variations in calcium concentration in the plant cell are decoded and relayed by calcium sensor proteins. Among these proteins, we find the CMLs or "Calmodulin-Like" proteins. During my thesis, we identified that CML8 participates in the immune responses of the plant to multiple pathogenic microorganisms including the soil bacterium Ralstonia solanacearum capable of infecting more than 200 species of plants (Arabidopsis thaliana, tomato, banana), the leaf bacterium Xanthomonas campestris pv. campestris and the root oomycete Phytophtora capsici. The objective of my thesis project was to clarify the function of CML8 in order to understand its role in plant immunity, and more precisely in the defense response of the plant Arabidopsis thaliana to Ralstonia solanacearum. To achieve this purpose, a transcriptomic approach by RNA-sequencing allowed to identify the molecular mechanisms dependent on CML8 in response to an infection by Ralstonia solanacearum. Also, CML8 is preferentially expressed at the level of lateral root emergences and controls the root architecture in an auxin-dependent manner. These emergences are the site of accumulation of endogenous auxin in the plant but also the point of entries of Ralstonia solanacearum into the plant. Knowing this and also knowing that the sequencing of Ralstonia solanacearum's genome has shown that it was possible that this bacterium could synthesize auxin, we chose to study the infection processes of Ralstonia solanacearum by seeking to identify the putative auxin biosynthetic pathway(s) in Ralstonia solanacearum in order to determine the role of auxin produced by the bacterium during the interaction with the plant

PtrA is required for coordinate regulation of gene expression during phosphate stress in a marine Synechococcus

Previous microarray analyses have shown a key role for the two-component system PhoBR (SYNW0947, SYNW0948) in the regulation of P transport and metabolism in the marine cyanobacterium Synechococcus sp. WH8102. However, there is some evidence that another regulator, SYNW1019 (PtrA), probably under the control of PhoBR, is involved in the response to P depletion. PtrA is a member of the cAMP receptor protein transcriptional regulator family that shows homology to NtcA, the global nitrogen regulator in cyanobacteria. To define the role of this regulator, we constructed a mutant by insertional inactivation and compared the physiology of wild-type Synechcococcus sp. WH8102 with the ptrA mutant under P-replete and P-stress conditions. In response to P stress the ptrA mutant failed to upregulate phosphatase activity. Microarrays and quantitative RT-PCR indicate that a subset of the Pho regulon is controlled by PtrA, including two phosphatases, a predicted phytase and a gene of unknown function psip1 (SYNW0165), all of which are highly upregulated during P limitation. Electrophoretic mobility shift assays indicate binding of overexpressed PtrA to promoter sequences upstream of the induced genes. This work suggests a two-tiered response to P depletion in this strain, the first being PhoB-dependent induction of high-affinity PO4 transporters, and the second the PtrA-dependent induction of phosphatases for scavenging organic P. The levels of numerous other transcripts are also directly or indirectly influenced by PtrA, including those involved in cell-surface modification, metal uptake, photosynthesis, stress responses and other metabolic processes, which may indicate a wider role for PtrA in cellular regulation in marine picocyanobacteria