CONICET | Buscador de Institutos y Recursos Humanos

The hypothesis presented here is that oxidative and/or nitrosative metabolism in the bivalve Mytilus edulisplatensis is altered by the presence of planktonic toxins. Digestive glands (DG) were isolated from specimenscollected in the Argentinean Sea during summer, winter and spring (in the presence of harmful planktonictoxins). The labile iron pool content was not significantly different in DG from animals collected in summerand winter, but was 2.3-fold increased in samples from spring compared to summer collected mollusks. The2??,7?? dichlorofluorescein diacetate (DCFH-DA) oxidation, ascorbyl radical/ascorbate and lipid radical/?¿-tocopherol content ratios showed no significant differences between samples collected in winter and summer.However, spring collected samples showed significantly higher DCFH-DA oxidation rate and oxidative ratios incomparison toDGfrommollusks collected in summer. Superoxide dismutase activity decreased by 75% inwinter,and 93% in spring, compared to samples collected in summer. Glutathione S-transferase activity decreased by 89%in winter, and 30% in spring, compared to samples collected in summer. Catalase activity in winter animals increasedby 3.8-fold in comparison to summer values, with no differences between spring and summer collectedmollusks. Nitrite plus nitrate content was not significantly different among samples collected in the three seasons,but nitric oxide content was 8.5- and 2.7-fold higher in samples from winter and spring collected mollusksthan values obtained in summer, respectively. These results showed the lack of effects of climatic changes on theintegrative oxidative indexes; however, under exposure to toxins, both oxidative and nitrosative metabolismswere affected.