Stress proteins (HSP's): Methods of detection and their use as an environmental biomarker

This paper briefly reviews the nomenclature and application of stress proteins as biomarkers, then gives a step by step description of the popular methodologies used to measure stress protein in plant and animal tissues together with a critic of each approach and trouble shooting tips. Stress proteins (previously termed 'heat shock proteins'') are induced by many environmental stresses including exposure to trace metals or organic pollutants, changes in temperature or osmolarity, hypoxia/anoxia, and exposure to ultraviolet radiation. Stress proteins, especially hsp70 and hsp60, have been used as biomarkers in a range of algae, invertebrates, fish, and higher vertebrates. Several suggestions are made to improve the utility of stress proteins as a biomarker of exposure e.g., consideration of the kinetics of stress protein induction relative to the pharmacokinetics of pollutant accumulation in the organism of concern, and selection of the type of stress protein for biomonitoring. The methodologies described include sample preparation, western blotting, slot blotting, and antibody detection methods, especially for hsp70. Western blotting has been the most widely applied technique for assaying stress proteins but dot/slot blotting with the inclusion of an internal standard in each gel improves the approach by simplifying the technique - saving time and materials and producing a more quantitative result.