Le « cadastre du risque avéré »

Le « cadastre des maladies environnementales » pointait, sur Google Maps, les micro-milieux ayant été cause directe d’au moins un cas avéré de maladie évitable : qui veut assainir le territoire doit savoir où se situe le risque. Produit d’un système ergonomique intégré à la pratique curative quotidienne d’un petit réseau de médecins volontaires, il restituait les informations collectées jour après jour selon une procédure rigoureuse mais non figée, dotée d’un langage et d’outils spécifiques, définie comme « parcours du soupçon à la connaissance des situations à risque. » Cas après cas, reliant le savoir scientifique universel aux connaissances « terroirisées » des personnes prises en charge, cette expérience a produit, entre 1994 et 2016, des résultats intéressants tant du point de vue de la connaissance et de l’assainissement des situations nocives que du développement d’une médecine moins consumériste.The “land register of environmental disease” pointed out, on Google Maps, the micro-environments having been the direct cause of at least one proven case of preventable disease: whoever wants to clean up the territory must know where the risk lies. The product of a system integrated into the daily curative practice of a small network of volunteer general physicians, it restituted the information collected day after day according to a rigorous but not fixed procedure, equipped with a specific language and tools, defined as “a path from suspicion to knowledge of risk situations.” Case after case, linking universal scientific knowledge to the “terroirized” knowledge of the people under care, this experiment produced, between 1994 and 2016, interesting results both from the point of view of the knowledge and remediation of harmful situations and the development of a less consumerist medicine

Evidence for an RNA Polymerization Activity in Axolotl and Xenopus Egg Extracts

We have previously reported a post-transcriptional RNA amplification observed in vivo following injection of in vitro synthesized transcripts into axolotl oocytes, unfertilized (UFE) or fertilized eggs. To further characterize this phenomenon, low speed extracts (LSE) from axolotl and Xenopus UFE were prepared and tested in an RNA polymerization assay. The major conclusions are: i) the amphibian extracts catalyze the incorporation of radioactive ribonucleotide in RNase but not DNase sensitive products showing that these products correspond to RNA; ii) the phenomenon is resistant to α-amanitin, an inhibitor of RNA polymerases II and III and to cordycepin (3′dAMP), but sensitive to cordycepin 5′-triphosphate, an RNA elongation inhibitor, which supports the existence of an RNA polymerase activity different from polymerases II and III; the detection of radiolabelled RNA comigrating at the same length as the exogenous transcript added to the extracts allowed us to show that iii) the RNA polymerization is not a 3′ end labelling and that iv) the radiolabelled RNA is single rather than double stranded. In vitro cell-free systems derived from amphibian UFE therefore validate our previous in vivo results hypothesizing the existence of an evolutionary conserved enzymatic activity with the properties of an RNA dependent RNA polymerase (RdRp)

The phosphoinositide 3-kinase (PI3K) pathway and glycogen synthase kinase-3 (GSK-3) positively regulate the activity of metal-responsive transcription factor-1 (MTF-1) in response to zinc ions.

Metal-responsive transcription factor-1 (MTF-1) is a metal-regulatory transcription factor essential for induction of the genes encoding metallothioneins (MTs) in response to transition metal ions. Activation of MTF-1 is dependent on the interaction of zinc with the zinc fingers of the protein. In addition, phosphorylation is essential for MTF-1 transactivation. We previously showed that inhibition of phosphoinositide 3-kinase (PI3K) abrogated Mt expression and metal-induced MTF-1 activation in human hepatocellular carcinoma (HCC) HepG2 and mouse L cells, thus showing that the PI3K signaling pathway positively regulates MTF-1 activity and Mt gene expression. However, it has also been reported that inhibition of PI3K has no significant effects on Mt expression in immortalized epithelial cells and increases Mt expression in HCC cells. To further characterize the role of the PI3K pathway on the activity of MTF-1, transfection experiments were performed in HEK293 and HepG2 cells in presence of glycogen synthase kinase-3 (GSK-3), mTOR-C1 and mTOR-C2 inhibitors as well as of siRNAs targeting Phosphatase and TENsin homolog (PTEN). We showed that inhibition of the mTOR-C2 complex inhibits the activity of MTF-1, in HepG2 and HEK293 cells, while inhibition of the mTOR-C1 complex or of PTEN stimulates MTF-1 activity in HEK293 cells. These results confirm that the PI3K pathway positively regulates MTF-1 activity. Finally, we showed that GSK-3 is required for MTF-1 activation in response to zinc ions.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Fos - Étang de Berre. Un littoral au cœur des enjeux environnementaux

Les espaces littoraux méditerranéens situés entre le grand Rhône et l’étang de Berre ont, au cours des trois derniers siècles, fait l’objet de projets d’industrialisation successifs qui frappent par leur démesure. C’est plus particulièrement le cas des travaux engagés à la fin des années 1960. Le golfe de Fos a été dédié à la pétrochimie, la métallurgie, au traitement des déchets et plus récemment, au fret et à la logistique. L’étang de Berre, déjà considérablement affecté par des pollutions aux hydrocarbures, a été sacrifié sur l’autel de l’économie pétrolière et de la production hydroélectrique. Les effets environnementaux et sanitaires ont été immédiats, provoquant la mobilisation de riverains bien décidés à obtenir de l’Etat qu’il les protège. Ce numéro spécial prend appui sur des travaux interdisciplinaires engagés depuis plusieurs années pour mettre en lumière les vulnérabilités d’un des principaux espaces productifs français. Ne se contentant pas de documenter la catastrophe chronique qui s’y joue, il souligne certaines des forces de ce territoire qui pourraient nous inspirer pour habiter plus précautionneusement l’anthropocène

Versatile Gene-Specific Sequence Tags for Arabidopsis Functional Genomics: Transcript Profiling and Reverse Genetics Applications

Microarray transcript profiling and RNA interference are two new technologies crucial for large-scale gene function studies in multicellular eukaryotes. Both rely on sequence-specific hybridization between complementary nucleic acid strands, inciting us to create a collection of gene-specific sequence tags (GSTs) representing at least 21,500 Arabidopsis genes and which are compatible with both approaches. The GSTs were carefully selected to ensure that each of them shared no significant similarity with any other region in the Arabidopsis genome. They were synthesized by PCR amplification from genomic DNA. Spotted microarrays fabricated from the GSTs show good dynamic range, specificity, and sensitivity in transcript profiling experiments. The GSTs have also been transferred to bacterial plasmid vectors via recombinational cloning protocols. These cloned GSTs constitute the ideal starting point for a variety of functional approaches, including reverse genetics. We have subcloned GSTs on a large scale into vectors designed for gene silencing in plant cells. We show that in planta expression of GST hairpin RNA results in the expected phenotypes in silenced Arabidopsis lines. These versatile GST resources provide novel and powerful tools for functional genomics