Coote P J, Cole M B, Jones M V
Unilever Research, Colworth Laboratory, Sharnbrook, Bedford, UK.
J Gen Microbiol. 1991 Jul;137(7):1701-8. doi: 10.1099/00221287-137-7-1701.
Incubation of Saccharomyces cerevisiae at sub-lethal temperatures results in an increase in thermotolerance. This process is dependent not only on the sub-lethal temperature but also on the duration of sub-lethal heating. This indicates that the mechanism inducing thermotolerance is a time/temperature dose response. Other factors that induce thermotolerance include exposure to ethanol, sorbic acid and low external pH values. These factors induce thermotolerance after incubation in the presence of protein synthesis inhibitors, and they are all known to affect the intracellular pH (pHi). The acquisition of increased thermotolerance is minimal with sub-lethal heating under neutral external pH conditions. However, when the external pH is reduced to 4.0 the level of induced thermotolerance increases to a maximum value. Using a specific ATPase inhibitor, diethylstilboestrol (DES), ATPase activity was shown to be essential for the cell to survive heat stress. In addition, measurement of acid efflux, or ATPase activity, revealed that proton pumping from the cell increased by approximately 50% at sublethal temperatures that induce thermotolerance. This work has clearly implicated pHi perturbation as the triggering mechanism conferring thermotolerance on S. cerevisiae.
将酿酒酵母在亚致死温度下培养会导致耐热性增加。这个过程不仅取决于亚致死温度，还取决于亚致死加热的持续时间。这表明诱导耐热性的机制是一种时间/温度剂量反应。其他诱导耐热性的因素包括暴露于乙醇、山梨酸和低外部pH值。这些因素在蛋白质合成抑制剂存在下培养后诱导耐热性，并且它们都已知会影响细胞内pH（pHi）。在中性外部pH条件下，亚致死加热导致的耐热性增加最小。然而，当外部pH降至4.0时，诱导的耐热性水平增加到最大值。使用特定的ATP酶抑制剂己烯雌酚（DES），ATP酶活性被证明对细胞在热应激下存活至关重要。此外，酸外流或ATP酶活性的测量表明，在诱导耐热性的亚致死温度下，细胞的质子泵出增加了约50%。这项工作清楚地表明pHi扰动是赋予酿酒酵母耐热性触发机制。
