EFFECTS OF COPPER ON ANTIOXIDANT ENZYM ES ACTIVITIES AND M ETALLOTHIONEIN CONCENTRATION OF BELLAM YA PUR IF ICATA

An experiment was conducted to study the effects of copper (Cu2+) on the antioxidant enzymes activities of the Bellamya purificat, such as superoxide dismatase (SOD), catalase (CAT), glutathione S-transferase (GST), concentrations of glutathione (GSH) and metallothionein (MT) at different concentrations of Cu2+(0, 0.005, 0.01, 0.02 and 0.05 mg/L) and different exposure times (0-14d). In order to evaluate the mechanisms of oxidative stress and damnification of Cu2+ on B. purificat, gills and livers were chosen to analyse the biochemical responses, because these organs were brought into contactwith environmental pollutants nearly. The results showed that Cu2+ had significant influence on the activities of SOD, CAT, GST and the concentrations of GSH, MT in both gills and livers of B. purificat, and such effects are significantly related to increased exposure time and dosage. The antioxidant enzymes activities in gills and livers could be markedly activated at the beginning days of Cu2+ exposure, such as SOD in 4d, CAT in 3d, and GST in 4d after exposure. The activities of SOD, CAT and GST decreased with the increase of exposure time, till theywere inclined to be inhibited in the 5d. On the last day of exposure, the antioxidant enzymes activities in treatmentswith 0.005mg/L of Cu2+ approached to the normal value, in 0.05 mg/L of Cu2+ were inhibited, and in 0.01mg/L of Cu2+ were induced. The activities of enzymes in treatments with 0.02 mg/L of Cu2+ was activated in liver and reversed in gill. Changes of GSH in livers and gills consisted with that of GST, which was enhanced when Cu2+ exposure began in several days. GSH concentrations in liverswere induced after 5-day-Cu2+ exposure, which in gills were induced after 4-day-Cu2+ exposure. GSH contents increased in low dosage (0.005 mg/L) group and decreased in high dosage (0.05 mg/L) group along with continuous Cu2+ exposure. TheMTs (concentration of metallothionein) in livers and gills of B. purificat were induced during the whole exposure process. MTs in all groups increased significantly within 12h Cu2+ exposure (p 2+ was extremely significantly induced during the whole process (p 2+. These results suggested that all these parameters above were sensitive to the exposure of Cu2+ and could be used as biomarkers to evaluate the aquatic environment Cu2+ pollution and its ecological risk.