SYNTHESIS AND ACCUMULATION OF STRESS PROTEINS IN TISSUES OF ARSENITE-EXPOSED FATHEAD MINNOWS (PIMEPHALES-PROMELAS)

The stress protein response (SPR) is a ubiquitous, protective, and defensive mechanism that enables cells to tolerate environmental perturbations. Induction of the SPR involves the increased transcription of stress protein genes, the products of which function in protein folding, multimeric protein assembly, receptor interactions, and heme catabolism, and so forth. The potential of this response as an indicator of water quality was evaluated in gill and striated muscle tissues of fathead minnows (Pimephales promelas) exposed to a wide range of concentrations of sodium arsenite for various lengths of time. The SPR in gill was elicited rapidly, occurring by 2 h exposure at 25 mg/L. The response was tissue specific. In gill, synthesis and accumulation rates of 20-, 40-, 70-, 72-, and 74-kD proteins were significantly increased, compared to controls. In muscle, 20-, 30-, 68-, 70-, and 90-kD proteins also showed significantly increased syntheses and accumulations. Synthesis and accumulation rates of arsenite-induced proteins 20-, 70-, 72-, and 74-kD in gill were significantly correlated with mortality. However, in striated muscle, only the 70-kD was significantly correlated with mortality.