Protein production during heat stress and exposure to toxicants in alcaligenes eutrophus JMP228

Abstract

AbstractIn an effort to determine whether heat‐shock proteins might serve as useful indicators of environmental stress, the aquatic bacterium, Alcaligenes eutrophus JMP228, was exposed to two chemical stressors: a toxic heavy metal ion, cadmium, and a nonbiodegradable organic herbicide, 2,4,5‐trichlorophenoxyacetic acid (2,4,5‐T). Protein synthesis was analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis, comparing the protein patterns of chemically stressed cells to those exhibited by nontreated and heat‐shocked cells. Heat‐shock proteins were produced in response to both chemical stressors and heat. Proteins induced in response to all three experimental stresses include molecules with approximate molecular weights of 58–60 and 106 kDa. Still other stress proteins were only expressed following chemical stress. A 106 kDa protein was only produced following cadmium treatment, whereas proteins of 37, 39, 46, 49, and 77 kDa were only produced in response to 2,4,5‐T. The synthesis of some of the unique stress proteins varied in a dose‐dependent fashion with the concentration of the individual stressors. The presence of these proteins may be useful indicators of the “health” of an environment. © 1993 John Wiley & Sons, Inc.