@article {3506, title = {Sub-chronic exposure to fluoxetine in juvenile oysters (Crassostrea gigas): uptake and biological effects.}, journal = {Environ Sci Pollut Res Int}, year = {2016}, month = {2014 Oct 15}, abstract = {

The bioconcentration potential of fluoxetine (FLX) and its biological effects were investigated in juvenile Pacific oyster exposed for 28\ days to environmentally relevant concentrations of FLX (1\ ng L(-1), 100\ ng L(-1) and up to 10\ μg\ L(-1)). FLX bioaccumulated in oyster flesh resulting in 28-day bioconcentration factors greater than 2,000 and 10,000 by referring to wet and dry weights, respectively. Nevertheless, FLX did not induce oyster mortality, delayed gametogenesis, or lead to adverse histopathological alterations. At the two highest concentrations, despite non-optimal trophic conditions, FLX stimulated shell growth but only in a transient manner, suggesting a role of serotonin in the regulation of feeding and metabolism in bivalves. Those high concentrations seemed to drive bell-shaped responses of catalase and glutathione S-transferase activities throughout the exposure period, which may indicate the activation of antioxidant enzyme synthesis and then an enhanced catabolic rate or direct inhibition of those enzymes. However, no clear oxidative stress was detected because no strong differences in thiobarbituric acid-reactive substance (TBARS) content (i.e. lipid peroxidation) were observed between oyster groups, suggesting that cellular defence mechanisms were effective. These results demonstrate the importance of considering additional biomarkers of oxidative stress to obtain a comprehensive overview of the FLX-induced changes in marine bivalves exposed under realistic conditions. Considering the battery of biomarkers used, FLX appears to induce little or no effects on oyster physiology even at a concentration of 10\ μg\ L(-1). These results do not confirm the lowest observed effect concentration (LOEC) values reported by some authors in other mollusc species.

}, issn = {1614-7499}, doi = {10.1007/s11356-014-3702-1}, author = {Di Poi, C and L Evariste and S{\'e}guin, Alexis and Mottier, A and Pedelucq, Julie and Jean-Marc Lebel and Antoine Serpentini and Budzinski, H{\'e}l{\`e}ne and Katherine Costil} } @article {3505, title = {Effects of subchronic exposure to glyphosate in juvenile oysters (Crassostrea gigas): From molecular to individual levels.}, journal = {Mar Pollut Bull}, year = {2015}, month = {2014 Oct 30}, abstract = {

Glyphosate-based herbicides are extensively used and can be measured in aquatic ecosystems, including coastal waters. The effect of glyphosate on non-target organisms is an issue of worldwide concern. The aim of this study was to investigate the effects of subchronic exposure to glyphosate in juvenile oysters, Crassostrea gigas. Yearling oysters were exposed to three concentrations of glyphosate (0.1, 1 and 100μgL(-1)) for 56days. Various endpoints were studied, from the individual level (e.g., gametogenesis and tissue alterations) to the molecular level (mRNA quantification), including biochemical endpoints such as glutathione-S-transferase (GST) and catalase activities and malondialdehyde content. No mortality and growth occurred during the experiment, and individual biomarkers revealed only slight effects. The levels of gene expression significantly increased in oysters exposed to the highest glyphosate concentration (GST and metallothioneins) or to all concentrations (multi-xenobiotic resistance). These results suggested an activation of defence mechanisms at the molecular level.

}, issn = {1879-3363}, doi = {10.1016/j.marpolbul.2014.10.026}, author = {Mottier, A and S{\'e}guin, Alexis and Devos, Alexandre and Le Pabic, C and Voiseux, C and Lebel, Jean-Marc and Antoine Serpentini and Fievet, B and Katherine Costil} } @article {3511, title = {Effects of acute exposures to mecoprop, mecoprop-p and their biodegradation product (2-MCP) on the larval stages of the Pacific oyster, Crassostrea gigas.}, journal = {Aquat Toxicol}, volume = {146}, year = {2014}, month = {2014 Jan}, pages = {165-75}, abstract = {

Studies have shown that pesticides are sometimes detected at rather high levels in seawater and it has been suggested that these chemical compounds could act as additional stress factor for oysters cultured in coastal environments. The effects of pesticides on marine molluscs could be particularly harmful in the early stages which correspond to critical life stages. This study aimed to assess the effects of mecoprop, mecoprop-p and their degradation compound 2-methyl-4-chlorophenol on two larval stages of Crassostrea gigas. Embryotoxic effects were assessed on veliger larvae after 36 h exposures, and both percentages of normal larvae and types of abnormalities were taken into account. The effects of the three substances were evaluated on 21-day-old pediveliger larvae by calculating metamorphosis rates after 24h exposures. The results of the embryotoxicity assay indicated that 2-methyl-4-chlorophenol was more toxic (EC50: 10.81 mg L(-1)) than its parent compounds (EC50 mecoprop: 42.55 mg L(-1); EC50 mecoprop-p: 78.85 mg L(-1)). Mecoprop in particular injured shell formation with an increase of shell abnormalities following herbicide concentrations. The active substances were not toxic to metamorphosis processes, but 2-MCP was revealed to be more toxic to the success of metamorphosis (EC50: 7.20 mg L(-1)) than to embryo-larval development. However, the toxic concentrations were several orders of magnitude higher than environmental concentrations.

}, keywords = {2-Methyl-4-chlorophenoxyacetic Acid, Animals, Chlorophenols, Crassostrea, Embryo, Nonmammalian, Larva, Metamorphosis, Biological, Water Pollutants, Chemical}, issn = {1879-1514}, doi = {10.1016/j.aquatox.2013.11.008}, author = {Mottier, A and Kientz-Bouchart, Val{\'e}rie and Dubreule, Christelle and Antoine Serpentini and Jean-Marc Lebel and Katherine Costil} }