ARE THE STRESS PROTEINS INDICATORS OF EXPOSURE OR EFFECT

The stress-inducible proteins (SP) and particularly the heat-shock proteins (HSP) are general biological indicators of contamination. Their functions are becoming increasingly understood, some SP have been associated with classes of stressors, others with specific diseases. In this paper, evidence is presented that SP are synthesized in greater quantities in increasing concentrations of stressor. Both HSP70 and HSP90 were sensitive in Daphnia magna to concentration of AgCl and SDS. Evidence taken from the literature indicates that subsets of SP induced vary with specific stressors or classes of stressors. Thus, the SP may provide general and specific tests of exposure. As tests of effects (or toxicity), the SP are less well proven. There is correlational evidence based on studies of SP and organismal responses, but there is little direct evidence on SP levels and toxic effects.