[Temperature-induced radioresistance of Escherichia coli cells]

A marked increase in radioresistance of E. coli cells, of the wild-type repair genotype, was observed when they were exposed to gamma-radiation at 40-45 degrees C. The effect of the thermoinduced radioresistance did not depend on the growth medium and the pre-incubation temperature but disappeared completely after treatment of cells by chloramphenicol or CaCl2 or after modification of cell membranes by exogenous cholesterol. This phenomenon was not observed with UV-irradiation. It is suggested that the thermoinduced radioresistance is connected with the activation of the membrane-associated repair complex.