REID, I.*; CATAPANE, E.J.; CARROLL, M.A.; Medgar Evers College, Brooklyn, NY; Medgar Evers College, Brooklyn, NY; Medgar Evers College, Brooklyn, NY: Effect of Copper on Glutathione S-Transferase Activity in the American Oyster, Crassostrea virginica

Jamaica Bay (JB), NY contains copper and other pollutants in levels higher than NYS Water Quality Standards. Bivalves are used for metal monitoring and bioaccumulation kinetics studies but little is known about their biochemical responses to metal accumulations. Previously we showed Crassostrea virginica transplanted to JB accumulated copper and other metal pollutants. Metal accumulations increase oxidative stress by various means including depletion of antioxidants such as reduced glutathione (GSH). Glutathione S-transferases (GSTs) are a ubiquitous group of Phase II detoxification enzymes that catalyze conjugation of electrophilic substrates to GSH. While studies have been done in mammals and other vertebrates less is known of invertebrates. GST activity was measured spectrophotometrically using CDNB and GSH as substrates, and calculated using the conjugate’s molar extinction coefficient. We demonstrated an in vitro inhibitory effect of three metal pollutants, Cu⁺², Fe⁺³ and Hg⁺² on GST activity from the post-mitochondrial fraction of C. virginica gill, that GSH has a protective effect against Cu⁺² but not Fe⁺³ or Hg⁺², that the mechanism of Cu⁺² inhibition is different from that of Fe⁺³ or Hg⁺², that oysters from copper polluted areas have lower GST activity that those from unpolluted areas, and oysters from clean sites have decreased GST activity when placed in copper polluted water. Understanding toxicological effects and adaptations of C. virginica to metal pollutants should affect decisions made by federal and local regulators protecting ecosystems. The work was supported by grants 1R25GM62003 of NIGMS, 0516041071 of NYSDOE, the CUNY Groundworks Program, and 66288-0035 of PSC-CUNY. We thank Frank M. Flower & Sons, Inc., Oyster Bay, NY for supplying oysters.