Oxidative stress in Laeonereis acuta (Polychaeta, Nereididae): environmental and seasonal effects

Abstract

Laeonereis acuta was seasonally collected in an industrially polluted site (P) and in an unpolluted site (UP) at the Patos Lagoon estuary (southern Brazil). Glutathione S-transferase (GST), superoxide dismutase (SOD) and catalase (CAT) activity (U/mg protein) was determined in five groups of worms from each site. Metallothionein (MT – lmol GSH/g ww) and lipid peroxides content (LPO – nmoles of cumene hydroperoxide/g ww) were also measured. Annual mean values for CAT (UP ¼ 3:7 _ 0:3; P ¼ 5:7 _ 0:6), GST (UP ¼ 0:034 _ 0:003; P ¼ 0:045 _ 0:004) and MT (UP ¼ 0:15 _ 0:02; P ¼ 0:23 _ 0:03) were higher ðp < 0:05Þ in worms from the P site. In autumn, CAT activity was higher ðp < 0:05Þ in worms from the P site (7.6_1.3) than in those from the UP site (3.6_0.4). In summer, MT concentration was higher in worms from the P site (0.37_0.03) than in those from the UP site (0.19_0.01). No significant difference ðp > 0:05Þ in the LPO content was observed in worms from the different sites or collected in different seasons. These results indicate that worms from the polluted site showed higher antioxidant responses than those from the unpolluted site, sufficient to prevent oxidative damage in terms of LPO.