Mise en évidence de protéines révélant une réponse au stress adaptative divergente entre les espèces Dreissena polymorpha et Dreissena rostriformis bugensis

International audienceZebra mussels Dreissena polymorpha, are bivalve molluscs used in ecotoxicology, as a sentinel species with, among other things, a strong bioaccumulation capacity. The quagga mussel, Dreissena rostriformis bugensis, has more recently colonized Western Europe. Also invasive, it competes with zebra mussels for habitats and, in some areas, has completely replaced it. Its use as a sentinel species is envisaged but requires understanding the mechanisms involved during the adaptive stress response and comparing them to those of the zebra mussel, which are better characterized. With this in mind, an exposure of the two species to a classical contaminant was performed to compare their responses. The individuals were exposed to a concentration of 100 μg / L of cadmium for 7 days, and then the gill proteins were separated by two-dimensional electrophoresis and the variable abundance proteoforms were identified by mass spectrometry. The functional analysis reveals promising elements for the study of the adaptive response in both species. A difference of expression of actors of the energy metabolism pathways points a physiological difference, with a reallocation of energy as well as the appearance of truncated proteins.Les moules zébrées, Dreissena polymorpha sont des mollusques bivalves utilisés en écotoxicologie comme espèces sentinelles du fait, entre autre, de leur capacité de bioaccumulation. La moule quagga, Dreissena rostriformis bugensis, a colonisé plus récemment l'Europe occidentale. Egalement invasive, elle est en compétition avec la moule zébrée pour les habitats et, dans certaines zones, l'a complètement remplacée. Son utilisation en tant qu'espèce sentinelle est envisagée mais nécessite de comprendre les mécanismes mis en jeu au cours de la réponse adaptative au stress et de les comparer à ceux de la moule zébrée, mieux caractérisés. Dans cette optique, une exposition des deux espèces à un contaminant classique a été réalisée afin de comparer leurs réponses. Les individus ont été exposés à une concentration de 100μg/L de cadmium pendant 7 jours, puis les protéines des branchies ont été séparées par électrophorèse bidimensionnelle et les protéoformes d'abondance variable ont été identifiées par spectrométrie de masse. L'analyse fonctionnelle révèle des éléments prometteurs pour l'étude de la réponse adaptative chez les deux espèces. Une différence d'expression d'acteurs des voies du métabolisme énergétique pointe une différence physiologique, avec une réallocation de l'énergie ainsi que l'apparition de protéines tronquées

Etude des adaptations du métabolisme protéique, en particulier, énergétique et oxydatif, en réponse à des changements physiologiques ou environnementaux : approche ciblée et approche globale

The present work has been conducted in a double ecotoxicological and metabolic context. The aim was to study protein modifications linked to chemical or physical disorders in order to highlight the molecular and physiological mechanisms of stress responses. Ultimately, this work is part of the search in tools for environmental diagnostics. Studied species are common sentinels in environmental monitoring, mainly marine and freshwater bivalves. Two approaches have been developed: an open approach based on the establishment and comparison of proteomic fingerprints; a targeted approach focused on enzymatic markers involved in stress response. Special attention was paid to the superoxide dismutase enzyme, which has been used as a new tool for discrimination of two neighboring species of dreissena.Ce mémoire présente des travaux menés dans un double contexte écotoxicologique et métabolique. Il s’est agi d’étudier les modifications protéiques liées à des stress chimiques ou physiques afin de mettre en évidence les mécanismes moléculaires et physiologiques de réponses aux stress. In fine ces travaux s’inscrivent dans la recherche d’outils de diagnostic environnementaux. Les modèles d’études sont des espèces utilisées en surveillance environnementale, principalement des bivalves d’eaux marines et d’eaux douces. Deux approches ont été menées : une approche ouverte basée sur l’établissement et la comparaison d’empreintes protéomiques ; une approche ciblée de mesures de marqueurs enzymatiques impliqués dans la réponse aux stress. Une attention particulière a été portée à l’enzyme superoxyde dismutase qui a été utilisée comme nouvel outil de discrimination de deux espèces voisines de dreissènes

The point about oxidative stress in molluscs

International audienceIn the normal metabolism of the aerobic cell, oxygen is used for various biochemical reactions. Because of its two lone electrons of parallel spins, the molecular oxygen is stable. However, oxygen generates Reactive Oxygenated Species or ROS by successive transfer of electrons. The ROS have a strong reactivity and can potentially interact with all other cellular components (lipids, proteins, DNA). They are at the origin of oxidations in chain by creating radicals. The cell has antioxidant systems which limit the effects of the ROS. These systems are composed of enzymes such as glutathione reductase, glutathione peroxidase, etc., and molecules of nonenzymatic nature like the reduced glutathione or vitamins. The production and the destruction of the radicals of oxygen coexist in a weak balance. If this balance is broken in favour of the ROS, an oxidative stress is generated. Xenobiotics could influence this balance by catalysing production of ROS

17β-Estradiol induces changes in cytokine levels in head kidney and blood of juvenile sea bass (Dicentrarchus labrax, L., 1758)

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The Politics of Some Policy Instruments

International audienceThis chapter offers a detailed sociological perspective on the role of investment-oriented policy instruments (subsidies, fixed tariffs, tenders) in triggering and shaping the recent development of renewable energies in three countries (France, Germany and Tunisia). Bringing together recent developments in STS (concerned markets, capitalisation), it shows that, despite their economic framing, these instruments trigger processes which deal with multiple values. They also sustain the emergence of collectives concerned with their effects – called their ‘milieu’ - which they become co-dependent upon. Such processes lead to iterative adjustments and developments that carry with them their own politics. While they sustain the emergence of political ends beyond those directly foregrounded by these instruments, they also prove to be very unevenly equipped to address emergent concerns

The Politics of Some Policy Instruments

International audienceThis chapter offers a detailed sociological perspective on the role of investment-oriented policy instruments (subsidies, fixed tariffs, tenders) in triggering and shaping the recent development of renewable energies in three countries (France, Germany and Tunisia). Bringing together recent developments in STS (concerned markets, capitalisation), it shows that, despite their economic framing, these instruments trigger processes which deal with multiple values. They also sustain the emergence of collectives concerned with their effects – called their ‘milieu’ - which they become co-dependent upon. Such processes lead to iterative adjustments and developments that carry with them their own politics. While they sustain the emergence of political ends beyond those directly foregrounded by these instruments, they also prove to be very unevenly equipped to address emergent concerns

A convenient device for xenobiotic dosing and haemolymph sampling in Carcinus maenas (Portunidae, Decapoda)

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