Antioxidant responses in gills of mussel (Mytilus galloprovincialis) as biomarkers of environmental stress along the Spanish Mediterranean coast.
ABSTRACT Antioxidant response was used to assess the effects of the main pollutants in wild mussels (Mytilus galloprovincialis) along the Mediterranean coast of Spain. Antioxidant enzyme activities - those of catalase, superoxide dismutase, glutathione peroxidases, glutathione reductase, glutathione S-transferase and DT-diaphorase - as well as lipid peroxidation and metallothionein concentrations were measured in gills of mussels from 16 selected sites. Furthermore, concentrations of the main contaminants (Hg, Pb, Cd, Cu, Zn, As, PAH, PCB, and DDT) were quantified in mussel tissue, and environmental parameters were measured in water samples collected at each site. Results showed that the glutathione-dependent antioxidant enzymes offered an increased and coordinated response against metal (Hg, Pb and Cd) contamination. These enzymatic activities correlated positively to temperature, suggesting the influence of this environmental parameter on antioxidant responses in gill tissues. Furthermore, although temperature did not reach stressful levels in the study area, it seemed to add a synergistic effect to that produced by metals to induce antioxidant enzymes in the most metal-polluted sites. Catalase activity appeared to be involved in a different antioxidant pathway, more related to organic pollutant bioaccumulation, offering an efficient protection mechanism against reactive oxygen species generation due both to organic exposure and high physiological activity, reflected by high condition indices. In general terms, increased levels of antioxidant enzymes at some sites suffering from metal and organic pollution indicated a situation of oxidative stress that nevertheless did not appear to be harmful, since lipid peroxidation levels showed no peroxidative damage in gill tissues of mussels collected from even the most heavily polluted sites. On the other hand, metallothionein and DT-diaphorase did not reflect pollutant exposure and seemed to be more influenced by environmental variables than by the pollutants.
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ABSTRACT: The activity of the antioxidant defence enzymes superoxide dismutase (SOD, EC 22.214.171.124), catalase (CAT, EC 126.96.36.199), glutathione peroxidase (GSH-Px, EC 188.8.131.52), glutathione reductase (GR, EC 184.108.40.206) and the phase II biotransformation enzyme glutathione-S-transferase (GST, EC 220.127.116.11) in whole mussels (Mytilus galloprovincialis) were studied. The mussels were collected in winter and in spring at two localities in the Adriatic Sea: Bar Port and Tivat Bay. Our results show that the activities of SOD, GSH-Px and GST were seasonally dependent with higher activities in winter. GR activity was also higher in winter, but only in mussels from Bar Port. In mussels from Tivat Bay, GR activity was lower in winter compared to spring. In addition, a decrease in CAT activity in mussels from Bar Port compared to those from Tivat Bay was found. It can be concluded that seasonal variations should be incorporated into interpretation of biomonitoring studies in mussels.Comparative Biochemistry and Physiology Part C Toxicology & Pharmacology 09/2005; 141(4):366-74. · 2.71 Impact Factor
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ABSTRACT: Combined effects of temperature and a toxic metal, cadmium (Cd), on energy metabolism were studied in a model marine bivalve, the eastern oyster Crassostrea virginica, acclimated at 20, 24 and 28 degrees C and exposed to 50microgl(-1) of Cd. Both increasing temperature and Cd exposure led to a rise in standard metabolic rates, and combined stressors appeared to override the capability for aerobic energy production resulting in impaired stress tolerance. Oysters exposed to elevated temperature but not Cd showed no significant change in condition, survival rate and lipid peroxidation, whereas those exposed to both Cd and temperature stress suffered high mortality accompanied by low condition index and elevated lipid peroxidation. Furthermore, RNA/DNA ratios indicative of protein synthesis rate, and levels of glutathione, which is involved in metal detoxification, increased in Cd-exposed oysters at 20 degrees C but not at 28 degrees C. Implications of the synergism between elevated temperatures and cadmium stress on energy metabolism of oysters are discussed in the light of the potential effects of climate change on oyster populations in polluted areas.Aquatic Toxicology 10/2006; 79(3):278-87. · 3.73 Impact Factor
- Bulletin of Environmental Contamination and Toxicology 09/2003; 71(2):270-5. · 1.11 Impact Factor