Thermotolerance and the heat-shock response in Candida albicans

Department of Microbiology and Immunology, UCLA School of Medicine, Los Angeles, California 90024, USA ABSTRACT SUMMARY: At elevated temperatures, yeast cells of Candida albicans synthesized nine heat-shock proteins (HSPs) with apparent molecular masses of 98, 85, 81, 76, 72, 54, 34, 26 and 18 kDa. The optimum temperature for the heat-shock response was 45°C although HSPs were detected throughout the range 41--46°C. Protein synthesis was not observed in cells kept at 48°C. Yeast cells survived exposure to an otherwise lethal temperature of 55°C when they had previously been exposed to 45°C. The thermotolerance induced during incubation at 45°C required protein synthesis, since protection was markedly reduced by trichodermin. Mercury ions induced a set of three stress proteins, one of which corresponded in size to an HSP, and cadmium ions evoked one stress protein seemingly unrelated to the HSPs observed after temperature shift.