URAIQAT, CA; SOMERO, GN; FIELDS, PA: The effect of anthropogenic organic pollution on glutathione S-transferase activity in the bay mussel, Mytilus galloprovincialis

Bioindicator organisms that accumulate toxins have an observable stress response to contaminants in the marine environment. We measured the activity of the detoxification enzyme glutathione S-transferase (GST) from the Bay Mussel (Mytilus galloprovincialis) as a bioindicator for the level of organic pollution at three sites in the San Francisco and Monterey bays with varying pollutant levels. Glutathione S-transferase activity was measured as the addition of 1-chloro-2,4-dinitrobenzene (CDNB) to reduced glutathione (GSH) to form CDNB-SH, at a wavelength of 340 nm. Activity was highest in M. galloprovincialis from the most polluted site, Moss Landing (0.0573 +/- 0.0226 mAbs/min/g tissue), intermediate in specimens from the Palo Alto site (0.0327 +/- 0.0140 mAbs/min/g tissue), and lowest in samples from the least polluted site, Monterey Marina (0.0228 +/- 0.0068 mAbs/min/g tissue, ANOVA p = 3.8 x 10^-6). Organisms from Moss Landing also had greater digestive gland masses per total tissue mass and higher protein concentrations than organisms from less polluted sites. The strong correlation between GST activity and toxin concentration suggests that bioindicator studies, in combination with water quality monitoring, provide a comprehensive view of the ecological implications of marine pollution.