Rhizobium metallidurans sp. nov., a symbiotic heavy metal resistant bacterium isolated from the Anthyllis vulneraria Zn-hyperaccumulator

International audienceA Gram-stain-negative, aerobic, rod-shaped, non-spore-forming bacterium (ChimEc512(T)) was isolated from 56 host seedlings of the hyperaccumulating Anthyllis vulneraria legume, which was on an old zinc mining site at Les Avinières, Saint-Laurent-Le-Minier, Gard, South of France. On the basis of 16S rRNA gene sequence similarities, strain ChimEc512(T) was shown to belong to the genus Rhizobium and to be most closely related to Rhizobium endophyticum CCGE 2052(T) (98.4%), Rhizobium tibeticum CCBAU 85039(T) (98.1%), Rhizobium grahamii CCGE 502(T) (98.0%) and Rhizobium mesoamericanum CCGE 501(T) (98.0%). The phylogenetic relationships of ChimEc512(T) were confirmed by sequencing and analyses of recA and atpD genes. DNA-DNA relatedness values of strain ChimEc512(T) with R. endophyticum CCGE 2052(T), R. tibeticum CCBAU 85039(T), R. mesoamericanum CCGE 52(T), Rhizobium grahamii CCGE 502(T), Rhizobium etli CCBAU 85039(T) and Rhizobium radiobacter KL09-16-8-2(T) were 27, 22, 16, 18, 19 and 11%, respectively. The DNA G+C content of strain ChimEc512(T) was 58.9 mol%. The major cellular fatty acid was C18 : 1ω7c, characteristic of the genus Rhizobium . The polar lipid profile included phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidylglycerol and phosphatidylcholine and moderate amounts of aminolipids, phospholipid and sulfoquinovosyl diacylglycerol. Although ChimEc512(T) was able to nodulate A. vulneraria, the nodC and nifH genes were not detected by PCR. The rhizobial strain was tolerant to high concentrations of heavy metals: up to 35 mM Zn and up to 0.5 mM Cd and its growth kinetics was not impacted by Zn. The results of DNA-DNA hybridizations and physiological tests allowed genotypic and phenotypic differentiation of strain ChimEc512(T) from species of the genus Rhizobium with validly published names. Strain ChimEc512(T), therefore, represents a novel species, for which the name Rhizobium metallidurans sp. nov. is proposed, with the type strain ChimEc512(T) ( =DSM 26575 = CIP 110550(T))

Thlaspi caerulescens, un indicateur de la pollution d'un sol ? Réflexion partagée entre étudiants et chercheurs autour d'un problème environnemental

International audienceCan the existence and the density of particular plant species give several informations about the degree of soil pollution? After having chosen different sites for this survey, the identification of collected plant species and the soil characteristics of collection sites were compared and some correlations were established. Data on growth of collected plants indicated the existence of two ecotypes of Thlaspi caerulescens. It has been shown the preference of one of the ecotypes for the metal-contaminated soils.La présence et l'abondance de certaines espèces végétales peuvent-elles donner des informations sur l'état de pollution d'un sol ? Après avoir choisi des sites d'étude, y avoir caractérisé des peuplements végétaux et la pollution du sol pour établir des corrélations, une mise en culture des plantes a permis de mettre en évidence deux écotypes de Thlaspi caerulescens et une préférence de l'un des deux pour les sols pollués. Mots-clés Pollutions minières, métaux lourds, bioindicateur, Thlaspi caerulescens, phytostabilisation

Ecological catalysis and phytoextraction: symbiosis for future

International audienceMetallophyte plants derived from phytoextraction are used as starting materials to prepare novel polymetallic catalysts. Polymetallic catalyst activity is used in many Lewis acid catalyzed reactions according to the polymetallic catalyst preparation. The synergetic catalysis of these systems leads to efficient syntheses of complex biomolecules such as dihydropyrimidinone, 5'-capped DNA and RNA, and glycosyl aminoacid. These new polymetallic catalysts also bring new possibilities in Green Catalysis, that we named "Ecological Catalysis"

Structure and composition of first biosourced Mn-rich catalysts with a unique vegetal footprint

International audienceEcological rehabilitation of degraded mining sites is necessary and possible by reintroducing pioneer manganese-accumulating plants. From the Mn-enriched biomass, our group has developed a process to recycle plant-derived metallic elements into innovative polymetallic catalysts, called Eco-Mn ecocatalysts. These first biosourced Mn-rich catalysts have demonstrated competitive catalytic activity in green organic synthesis. To expand the use of these catalysts in organic chemistry, their catalytic activity has to be correlated with their structure and properties. Thus, we put forward for the first time an extensive structural study of Eco-Mn catalysts, including composition analysis, crystalline structure analysis, and chemical environment around active catalytic center (manganese and iron) analysis. Density Functional Theory (DFT) calculations support our conclusions. Finally, this study highlights the peculiar vegetal footprint of Eco-Mn catalysts

Composante RAdioLogique de l'Exposome, multi-expositions, risques de cancers et d'autres pathologies chroniques dans la cohorte Constances : le projet CORALE

National audienceContexte L’ensemble de la population est multi-exposé tout au long de sa vie aux rayonnements ionisants (RIs) à des niveaux variables, via de multiples sources naturelles et artificielles, dans le cadre de l’environnement résidentiel, de différentes activités (ex: trajets aériens) ou pour raisons médicales (procédures diagnostiques ou thérapeutiques). Si le caractère cancérogène des RIs est solidement documenté pour des doses supérieures à 100 milliGrays, la quantification des effets de multi-expositions aux RIs et à d’autres facteurs de risque de cancer est peu documentée, excepté l’interaction entre tabac et radon sur le risque de cancer du poumon. Méthode CORALE permettra la reconstitution la plus exhaustive possible des doses de RIs d’origines environnementales (radon, rayonnements telluriques et cosmiques, alimentation, installations nucléaires et autres sources artificielles), médicales (procédures diagnostiques et thérapeutiques) et professionnelles reçues par les participants de la cohorte Constances depuis leur naissance. Ces reconstitutions seront effectuées par l'IRSN, en collaboration avec l'UMS INSERM/UVSQ gérant Constances, grâce à des croisements de données multiples : historiques résidentiels des participants depuis leur naissance, questionnaires, Système National des Données de Santé renseignant les expositions médicales, bases de données gérees par l’IRSN. CORALE estimera ensuite les risques de cancers et d’autres pathologies chroniques potentiellement associés aux doses cumulées reçues en tenant compte des multi-expositions documentées à d'autres facteurs de risque de ces pathologies.Résultats Le protocole de CORALE a été rédigé. Les résultats d’un pilote suggèrent que cette étude pourra être menée chez environ 100 000 participants. Un premier financement européen obtenu via le projet RadoNorm permettra de démarrer CORALE en 2021. Conclusion Constances dispose d’atouts majeurs pour progresser vers la caractérisation de l’exposome et de ses liens avec les pathologies chroniques. CORALE s’inscrit dans un programme de recherche à long terme sur les effets des multi-expositions aux RIs mais aussi à d’autres expositions environnementales. ObjectivesThe first objective of the CORALE project is to carry out the broadest possible reconstruction of doses of IR from environmental sources (radon, terrestrial and cosmic radiation, food, nuclear installations and other artificial sources), medical (diagnostic and therapeutic procedures) and occupational (nuclear workers but also other industries using radioactive sources, health professionals… ) received by participants in the Constances cohort since birth, following the logic of the exposome concept (for its radiological component). The second objective will be to estimate the risks of cancers and other chronic diseases potentially associated with the cumulative doses received (from several sources of IR and over time) taking into account the potential influence of the context of multi-exposures to other risk factors.MethodsIn order to reconstruct the annual doses due to radioactivity of natural and artificial origin received by each member of the Constances cohort since their birth, a large number of sources of radioactivity must be considered. Reconstructions related to environmental, medical and occupational exposures will be performed by different units of the IRSN in collaboration with the Constances cohort team. To do this, a questionnaire will be sent to cohort members who have already provided their residential histories. The statistical analyses (e.g., Cox models with time-dependent covariates) will be carried out at the IRSN epidemiology laboratory and will benefit from the expertise of radiobiologists, supporting the exploration of specific hypotheses and interpretations. The use of innovative regression methods on exposure profiles will be explored in collaboration with the University of Paris.PerspectivesCORALE is part of a broader long-term research programme, which will include the effects of other multi-exposures (e.g., IR and other environmental exposures) and the study of risk and exposure biomarkers through the Constances biobank, further complementing the application of the exposome concept through the study of within-body regulations following exposures. This program will help improve the characterization of the exposome and its relation with chronic diseases in the Constances cohort

Radiological component of the Exposome, multiple exposures, risks of cancer and other chronic diseases in the Constances cohort (CORALE)

International audienceContextThe whole population is exposed throughout its life to ionizing radiation (IR) at varying levels, via multiple natural and artificial sources, whether in the context of the residential environment, various activities (professional or other such as air travel) or for medical reasons (diagnostic or therapeutic procedures). The carcinogenic effects of IR are well documented at dose levels of 100 milliGrays (mGy) or higher. There is still controversy about the shape of the relationships between exposure and cancer risks at lower doses, called “low doses”. In addition, quantification of the effects of multi-exposure to IR and other cancer risk factors is poorly documented, with the exception of the interaction between tobacco and radon on lung cancer risk. Similarly, the relationships between exposures to IR at different stages of life (e.g., during childhood, puberty, etc.) and late health effects remain poorly characterized. Potential associations between low doses of IR and non-cancer chronic diseases also require better documentation. ObjectivesThe first objective of the CORALE project is to carry out the broadest possible reconstruction of doses of IR from environmental sources (radon, terrestrial and cosmic radiation, food, nuclear installations and other artificial sources), medical (diagnostic and therapeutic procedures) and occupational (nuclear workers but also other industries using radioactive sources, health professionals… ) received by participants in the Constances cohort since birth, following the logic of the exposome concept (for its radiological component). The second objective will be to estimate the risks of cancers and other chronic diseases potentially associated with the cumulative doses received (from several sources of IR and over time) taking into account the potential influence of the context of multi-exposures to other risk factors.MethodsIn order to reconstruct the annual doses due to radioactivity of natural and artificial origin received by each member of the Constances cohort since their birth, a large number of sources of radioactivity must be considered. Reconstructions related to environmental, medical and occupational exposures will be performed by different units of the IRSN in collaboration with the Constances cohort team. To do this, a questionnaire will be sent to cohort members who have already provided their residential histories. The statistical analyses (e.g., Cox models with time-dependent covariates) will be carried out at the IRSN epidemiology laboratory and will benefit from the expertise of radiobiologists, supporting the exploration of specific hypotheses and interpretations. The use of innovative regression methods on exposure profiles will be explored in collaboration with the University of Paris.PerspectivesCORALE is part of a broader long-term research programme, which will include the effects of other multi-exposures (e.g., IR and other environmental exposures) and the study of risk and exposure biomarkers through the Constances biobank, further complementing the application of the exposome concept through the study of within-body regulations following exposures. This program will help improve the characterization of the exposome and its relation with chronic diseases in the Constances cohort

Radiological and chemical exposures and risks of cancer in the Constances cohort (COREXCA)

International audienceBackground - Populations are exposed to ionizing radiation (IR) and chemical pollutants (CPs) at various levels, via multiple natural and artificial sources, in the context of the residential environment, workplace and/or for medical reasons (diagnostic or therapeutic procedures). The carcinogenic effects of IR are well documented above dose levels of 100 milliGrays, but still less well below. In addition, the effects of joint exposures to IR and CPs on cancer risks are poorly documented.Objectives - The first objective of COREXCA is to carry out the broadest possible reconstruction of life-long doses of IR and several carcinogenic CPs (cadmium, nickel and chromium) from environmental sources (e.g. : natural radioactivity, nuclear installations and other artificial sources) and occupational activities, but also medical exposures, received by around 80,000 participants of the French Constances cohort https://www.constances.fr/).The second objective will be to estimate cancer risks associated with the cumulative doses of IR and CPs received by these participants

Radiological and chemical exposures and risks of cancer in the Constances cohort (COREXCA)

International audienc

Radiological and chemical exposures and risks of cancer in the Constances cohort (COREXCA)

International audienc