La longue séquence pliocène de Marchésieux - Résultats analytiques et premiers résultats

National audienceLe sondage intégralement carotté de Marchésieux a permis d'atteindre l'objectif fixé dans le projet AR42 du BRGM : l'analyse paléoclimatique du premier épisode glaciaire de l'hémisphère nord (Prétiglien, -2,4 Ma) et probablement le premier rafraîchissement de -3,1 Ma. Les 159,3 m de sédiments datés du Reuvérien et du Prétiglien ont déjà livré une quantité importante d'informations aussi bien climatiques que paléoenvironnementales. De par sa position géographique privilégiée et de par son environnement côtier, la "Longue sequence" de Marchésieux a précisé les modalités de la séquence de dégradation climatique en milieu continental et marin à nos latitudes moyennes. La méthodologie fortement pluridisciplinaire, le plus souvent il très haute résolution, permet d'affiner notablement les modalités de la réponse de chaque environnement au changement climatique, et apparaît, en ce sens, beaucoup plus riche que les études monodisciplinaires classiques. Ainsi, les réponses zoologiques, phytosociologiques, sedimentologiques et géochimiques au stimulus climatique externe peuvent être comparées et calibrées

Brest, 57

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Inorganic arsenic increases IL-8 expression induced by lipopolysaccharide through activation of a reactive oxygen species/Src/p38-kinase signalling pathway

International audienc

A less humid climate since ca. 3500 yr B.P. from marine cores off Karwar, western India

International audienc

Trilobites and inarticulate brachiopods from the Devonian Floresta Formation of Colombia: a review

International audienceThe study of Devonian Colombian trilobites and inarticulate brachiopods allows to recognize two biostratigraphic levelswithin the Floresta Formation. The first level, in the lower part of the formation, is late Emsian in age, and yields 14 distincttrilobite taxa, including Colombianaspis carvalhoae gen. et sp. nov. The second one, in the upper part of the formation,is assigned to the Givetian based on the co-occurrence of the genera Dipleura and Greenops; this is the first recordof a Givetian age for the upper part of the Floresta Formation. The inarticulate brachiopods collected from the uppermostpart of the formation suggest a Givetian age. Inarticulate brachiopods as well as the trilobites show close affinities withthe North Eastern Americas Realm, but they also suggest European affinities. The late Emsian occurrence of calmoniidsfrom Colombia is indicative of restricted faunal exchanges with the Malvinokaffric Realm

Long term exposure to environmental concentrations of diesel exhaust particles does not impact the phenotype of human bronchial epithelial cells

International audienceChronic exposure to diesel engine exhausts is associated with an increased risk of pulmonary diseases including lung cancer. Diesel engine exhausts contain large amounts of diesel exhaust particles (DEP) on which are adsorbed several carcinogenic compounds such as polycyclic aromatic hydrocarbons. Acute toxicity of high concentrations of DEP has been largely demonstrated in various in vitro cellular models. In contrast, the cellular and molecular impacts of low environmental concentrations of DEP on the phenotype of chronically exposed lung epithelial cells remain to be investigated. In the present study, we show that long term exposure (6 months) to 2 μg/ml (0.4 μg/cm) DEP (standard reference material 1650b) increased cytochrome P4501A mRNA levels in the human bronchial epithelial BEAS-2B cell line. However, chronic exposure to DEP did not change cell morphology, trigger epithelial-mesenchymal transition or increase anchorage-independent cell growth. Moreover, DEP increase neither the levels of reactive oxygen species or those of γ-histone H2AX, nor the expression of interleukin-6 and interleukin-8. Our results thus demonstrate that the chronic exposure to low DEP concentrations could increase cytochrome P501A gene expression in BEAS-2B cells but did not induce molecular effects related to genotoxicity, oxidative stress or inflammation