Stress proteins and thermotolerance in psychrotrophic yeasts from arctic environments

Abstract

The protein synthetic responses to heat shock of two psychrotrophic yeasts Trichosporon pullulans and Sporobolomyces salmonicolor, isolated from the Arctic, were examined. The temperature of maximum heat shock protein induction was above the maximum temperature for growth in Trichosporon pullulans, but was within the physiological range in Sporobolomyces salmonicolor. Heat shock protein synthetic rates remained elevated in both microorganisms for at least 4 h when the temperature used for heat shock was within the physiological growth range. Both of these nonfermentative yeasts showed a protein synthetic response to recovery from anaerobiosis similar to that shown to heat shock. Trichosporon pullulans failed to show any increased resistance to a lethal thermal stress concomitant with the induction of stress proteins due to heat shock or recovery from anoxia.