title: Active and passive biomonitoring suggest metabolic adaptation in blue mussels (Mytilus spp.) chronically exposed to a moderate contamination in Brest harbor (France).
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.
authors: LEMAR-UMR 6539 UBO/CNRS/IRD/Ifremer-Institut Universitaire Européen de la Mer, Université de Bretagne Occidentale, 29280 Plouzané, France. Electronic address: camlacroix@hotmail.fr.
authors: Camille
authors: C
authors: Lacroix
authors: LEMAR-UMR 6539 UBO/CNRS/IRD/Ifremer-Institut Universitaire Européen de la Mer, Université de Bretagne Occidentale, 29280 Plouzané, France.
authors: Gaëlle
authors: G
authors: Richard
authors: LEMAR-UMR 6539 UBO/CNRS/IRD/Ifremer-Institut Universitaire Européen de la Mer, Université de Bretagne Occidentale, 29280 Plouzané, France; LPI-UMR 6539-IFREMER, 29280 Plouzané, France.
authors: Catherine
authors: C
authors: Seguineau
authors: CEDRE-715, Rue Alain Colas/CS 41836-29218 Brest Cedex 2, France.
authors: Julien
authors: J
authors: Guyomarch
authors: LEMAR-UMR 6539 UBO/CNRS/IRD/Ifremer-Institut Universitaire Européen de la Mer, Université de Bretagne Occidentale, 29280 Plouzané, France.
authors: Dario
authors: D
authors: Moraga
authors: LEMAR-UMR 6539 UBO/CNRS/IRD/Ifremer-Institut Universitaire Européen de la Mer, Université de Bretagne Occidentale, 29280 Plouzané, France.
authors: Michel
authors: M
authors: Auffret
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects*; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D001711:Biotransformation; D004734:Energy Metabolism / Q000187:drug effects; D004784:Environmental Monitoring / Q000379:methods*; D005602:France; D015227:Lipid Peroxidation / Q000187:drug effects; D049878:Mytilus / Q000187:drug effects* / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects; D011084:Polycyclic Aromatic Hydrocarbons / Q000378:metabolism / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000378:metabolism / Q000633:toxicity*; D014877:Water Pollution, Chemical / Q000009:adverse effects*
chemical_list: D015415:Biomarkers; D011084:Polycyclic Aromatic Hydrocarbons; D014874:Water Pollutants, Chemical
keywords: Bay of Brest; Blue mussel Mytilus spp.; Caging; Chronic pollution; Energetic metabolism; Marine biomonitoring; Oxidative stress