Thermotolerance and barotolerance of alcohol-shocked yeast

摘要

The acquisition of stress tolerance in response to a preconditioning alcohol shock treatment at various concentrations was studied using eight kinds of alcohols in he yeast Saccharomyces cerevisiae. Alcohol shock treatment induced tolerance against stres; es such as high temperature and high pressure in yeast. The optimum alcohol shock concentration that induces maximal tolerance against these stresses was dependent on the nature of alcohols. The optimum concentration was inversely proportional to the number of carbon atom in the alcohol molecules. Moreover, the position of the hydroxyl group in the alcohol molecules affected the degree of stress tolerance. Alcohol-shocked yeast also acquired barotolerance. These results show that the acquisition of stress tolerance is closely related with alcohol preconditioning and the nature of alcohols. Microcalorimetric measurement was done to estimate the strength of alcohols as stress substances or inhibitors for the growth of the yeast. From the data on the growth thermograms of yeast, the minimum inhibitory concentration (MIC) of alcohols was determined and correlated with the optimum alcohol concentration for alcohol shock.