Active and passive biomonitoring suggest metabolic adaptation in blue mussels (Mytilus spp.) chronically exposed to a moderate contamination in Brest harbor (France)

Type Article
Date 2015-05
Language English
Author(s) Lacroix Camille1, Richard Gaelle1, Seguineau Catherine1, 2, Guyomarch Julien3, Moraga Dario1, Auffret Michel1
Affiliation(s) 1 : Univ Bretagne Occidentale, European Univ Inst Mer, LEMAR, UMR UBO CNRS IRD Ifremer 6539, F-29280 Plouzane, France.
2 : IFREMER, LPI, UMR 6539, F-29280 Plouzane, France.
3 : CEDRE, F-29218 Brest 2, France.
Source Aquatic Toxicology (0166-445X) (Elsevier Science Bv), 2015-05 , Vol. 162 , P. 126-137
DOI 10.1016/j.aquatox.2015.03.008
WOS© Times Cited 50
Keyword(s) Marine biomonitoring, Chronic pollution, Blue mussel Mytilus spp., Caging, Oxidative stress, Energetic metabolism, Bay of Brest
Abstract Brest harbor (Bay of Brest, Brittany, France) has a severe past of anthropogenic chemical contamination, but inputs tended to decrease, indicating a reassessment of its ecotoxicological status should be carried out. Here, native and caged mussels (Mytilus spp.) were used in combination to evaluate biological effects of chronic chemical contamination in Brest harbor. Polycyclic aromatic hydrocarbon (PAH) contamination was measured in mussel tissues as a proxy of harbor and urban pollution. Biochemical biomarkers of xenobiotic biotransformation, antioxidant defenses, generation of reducing equivalents, energy metabolism and oxidative damage were studied in both gills and digestive glands of native and caged mussels. In particular, activities of glutathione-S-transferase (GST), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), NADP-dependent isocitrate dehydrogenase (IDP), pyruvate kinase (PK) and phosphoenolpyruvate carboxykinase (PEPCK) were measured and lipid peroxidation was assessed by malondialdehyde (MDA) quantification. In addition, a condition index was calculated to assess the overall health of the mussels. Moderate PAH contamination was detected in digestive glands of both native and caged individuals from the exposed site. Modulations of biomarkers were detected in digestive glands of native harbor mussels indicating the presence of a chemical pressure. In particular, results suggested increased biotransformation (GST), antioxidant defenses (CAT), NADPH generation (IDP) and gluconeogenesis (PEPCK), which could represent a coordinated response against chemically-induced cellular stress. Lipid peroxidation assessment and condition index indicated an absence of acute stress in the same mussels suggesting metabolic changes could, at least partially, offset the negative effects of contamination. In caged mussels, only GR was found modulated compared to non-exposed mussels but significant differences in oxidative stress and energy-related biomarkers were observed compared to native harbor mussels. Overall, these results suggested mussels chronically exposed to contamination have set up metabolic adaptation, which may contribute to their survival in the moderately contaminated harbor of Brest. Whether these adaptive traits result from phenotypic plasticity or genetic adaptation needs to be further investigated.
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Lacroix Camille, Richard Gaelle, Seguineau Catherine, Guyomarch Julien, Moraga Dario, Auffret Michel (2015). Active and passive biomonitoring suggest metabolic adaptation in blue mussels (Mytilus spp.) chronically exposed to a moderate contamination in Brest harbor (France). Aquatic Toxicology, 162, 126-137. Publisher's official version : https://doi.org/10.1016/j.aquatox.2015.03.008 , Open Access version : https://archimer.ifremer.fr/doc/00255/36654/