ASSESSMENT OF A GLUTATHIONE-S-TRANSFERASE AND RELATED PROTEINS IN THEGILL AND DIGESTIVE GLAND OF MYTILUS-EDULIS (L), AS POTENTIAL ORGANIC POLLUTION BIOMARKERS

The response of the glutathione S-transferase (GST, EC 2.5.1.18) and r elated proteins of Mytilus edulis to environmental pollution load was assessed. Mussels were reciprocally transplanted between an industrial estuary (Douglas), a rural estuary (Youghal) and a marine site (Bantr y). In addition, mussels were sampled along a pollution gradient in an estuary receiving leather tannery effluent (Colligan). These latter m ussels were previously shown to be subject to oxidative stress resulti ng from the discharges. GST specific activity of cytosolic extracts fr om the gill and digestive gland tissues was determined for all animals . Specific activity was shown to vary significantly in animals from di fferent sites, with highest specific activity always observed in sampl es (local and transplanted) taken from the industrial site. By compari son, the mussels exposed to tannery discharges displayed no significan t alteration in GST specific activity. Total intracellular glutathione (GSH) was also determined for samples taken from the Douglas and Youg hal estuaries but no correlation with pollution load was observed. Usi ng FPLC analysis, we observed no specific effect on the relative level s of the GST and the individual GST related proteins in gill or digest ive gland samples from local or reciprocally transplanted animals from Douglas or Youghal, The increase in GST specific activity observed in samples from the industrial estuary are indicative of a possible, spe cific inductive agent at this site. The results from the tannery site, by comparison, indicate that general oxidative stress does not result in elevated GST specific activity in M. edulis.