REID, I.; WALLACE, A.; CATAPANE, E.J.; CARROLL, M.A.; Kingsborough Community College; Medgar Evers College; Medgar Evers College; Medgar Evers College: Effects of Metal Pollutants on Glutathione S-Transferase Activity in Crassostrea virginica

Bivalves are used for metal monitoring and bioaccumulation kinetics studies, but little is know about their biochemical responses to metals which cause oxidative stress by enhancing production of reactive oxygen species, depleting reduced thiols like glutathione (GSH), or inactivating antioxidating enzymes. Glutathione S-transferase (GST) is involved in Phase II detoxification catalyzing conjugation of electrophilic substrates to GSH. Substrates may be hydrophobic organic xenobiotics or in some cases heavy metals. Little is known about GST in invertebrates. Jamaica Bay (JB) and areas of Oyster Bay (OB) in NY contain metals and other pollutants. We showed Crassostrea virginica spats transplanted to JB accumulated copper and other metals despite excellent survival and growth and that C. virginica preincubated in 100 mM copper sulfate had a 65% drop in gill GST activity. We studied in vitro effects of Cu⁺², Cd⁺², Fe⁺³, Hg⁺², and Pb⁺² on GST activity in gill. Preincubation with 50 µg Cu⁺² caused over 85% inhibition, and 125 µg Hg⁺² and Fe⁺³ caused inhibition of over 70%. The enzyme was most resistant to Cd⁺² or Pb⁺². Preincubation with low concentration of Cu⁺² and any of the other metals resulted in greater inhibition than either metal alone suggesting a synergistic effect. Better understanding of the toxicological effects and adaptation of C. virginica to heavy metal pollutants should affect decisions made by federal and local regulators that protect ecosystems and continue to improve water quality in the NY harbor vicinity and other coastal waterways. This work was supported by grants 1R25GM62003 of NIGMS, 0516011058 of the NYSDOE, 657200034 of PSC-CUNY and a CUNY Groundworks grant. We thank Frank M. Flower and Sons, Inc., Oyster Bay, NY for supplying oysters.