PARENT SESSION
41 - Physiological and Molecular Mechanisms of Toxicity
8:00 AM to 6:30 PM, Tuesday, 14 May 2002
Exhibition Area

(41-06) Oxidative stress responses of two populations of Laeonereis acuta (Polychaeta, Nereididae) after acute and chronic exposure to copper.

Geracitano, Laura^1,2, Faleiros, Markel¹, Bochetti, Rafaella³, Monserrat, José¹, Regoli, Francesco³, Bianchini, Adalto^*,1, ¹ Fundação Universidade Federal do Rio Grande (FURG), Rio Grande, RS, Brazil² Post-graduate course in Biological Oceanography (FURG)³ Università di Ancona, Italy

ABSTRACT- Acute (96 h) and chronic (14 days) effect of copper on the antioxidant defense system of Laeonereis acuta (Polychaeta Nereididae) collected in unpolluted (UP) and polluted (P) areas was evaluated. In the acute assay , two copper concentrations (125 and 250 g Cu/l) and one control group were tested. Superoxide dismutase (SOD) and glutathione-S-transferase (GST) activity did not change after copper exposure. Catalase (CAT) activity increased after copper exposure in worms from UP and P sites. Lipid peroxidation was higher in copper exposed worms from the P site. In the chronic assay, one copper concentration (62.5 g Cu/l) and one control group were tested. Polychaetes from the P site showed higher SOD, GTS and CAT activity than worms from the UP site. The response to copper exposure was also different in polychaetes from the P and UP sites. In worms from P site, enzyme activity did not change after copper exposure, except CAT which decreased. Animals from the UP site showed augmented SOD activity after copper exposure. Results suggest that the exposure time employed in the acute assay seems insufficient for synthesis of new SOD and GST. As total oxyradical scavenging capacity remained constant and CAT activity augmented after acute copper treatment, a decrease of non enzymatic antioxidant defenses could be inferred. Differences in response between animals collected at UP and P site after acute and chronic copper exposure suggest that animals from the P site are clearly under oxidative stress in the field.

Key words: copper, antioxidant defenses, oxidative stress, Polychaeta