Induction and enhancement of stress proteins in a trichloroethylene-degrading methanotrophic bacterium, Methylocystis sp. M

The responses of the trichloroethylene-degrading bacterium Methylocystis sp. M to six different water-pollutants, carbon starvation, and temperature-shock (heat and cold) were examined using 2-dimensional gel electrophoresis. Twenty-eight polypeptides were induced, and these stress-induced proteins were classified into three groups. Some of the chemically induced proteins were the same as those induced by carbon starvation and temperature-shock. Two of the polypeptides were induced by trichloroethylene. Trichloroethylene-stress protein synthesis required 1-2 h at a concentration of trichloroethylene that had no effect on growth. Furthermore, 25 stress-enhanced polypeptides were observed, and one of these was enhanced by trichloroethylene. Based on these results, we discuss applications of chemical-stress induction of proteins to establish effective bioremediation and bioassay by methanotrophs.