Depression of hyperthermic potentiation in cell killing of ultraviolet light-irradiated Dictyostelium discoideum by pre-heat treatment

Abstract

Heat treatment of 30 degrees C for 15 min immediately after ultraviolet (UV) irradiation enhanced cell killing of Dictyostelium discoideum. However, when the cells were heated at 30 degrees C for 15 min and then cultured for more than 10 min at 23 degrees C prior to UV exposure, the hyperthermic potentiation in cell killing was depressed. When these preheated cells were cultured in the presence of cycloheximide, the depression of the hyperthermic potentiation disappeared. These results suggest that the depression in hyperthermic potentiation may be the result of the induction of some heat-shock-type proteins.