【摘要】 生长阶段和冲击阶段均添加 1 6 4mmol LCa2 + 能显著提高自絮凝颗粒酵母于 30℃在 2 0 % (V V)酒精冲击下的存活率 ,经过 9h冲击 ,对照组的存活率为 0 ,而添加Ca2 + 试验组的存活率为 5 0 0 % ,表明添加适当浓度的Ca2 + 能显著提高菌体的耐酒精能力。通过考察Ca2 + 对菌体于 30℃在 15 % (V V)酒精冲击下细胞膜透性的影响发现 ,生长阶段和冲击阶段均添加 1 6 4mmol LCa2 + 的试验组的菌体胞外核苷酸平衡浓度和细胞膜透性系数 (P′)分别仅为对照组水平的 5 0 0 %和 2 9 3% ,表明添加适当浓度的Ca2 + 能显著降低受冲击菌体的细胞膜透性 ;而且 ,添加Ca2 + 提高存活率与添加Ca2 + 降低胞外核苷酸浓度和P′存在直接的对应关系。因此 ,Ca2 + 提高自絮凝颗粒酵母耐酒精能力是与其降低受冲击菌体的细胞膜透性密切相关的。更多还原

【Abstract】 Ca 2+ at 1 64 mmol/L markedly increased ethanol tolerance of a self_flocculating fusant of Schizosaccharomyces pombe and Saccharomyces cerevisiae. After 9 h of exposure to 20%(V/V) ethanol at 30℃ , no viability remained for the control whereas 50 0% remained for the cells both grown and incubated with ethanol in Ca 2+_added medium. Furthermore, when subjected to 15%(V/V) ethanol at 30℃, the equilibrium nucleotide concentration and plasma membrane permeability coefficient (P′ ) of the cells both grown and incubated with ethanol in Ca 2+_added medium accounted for only 50 0% and 29 3% those of the control respectively, indicating that adding Ca 2+ can markedly reduce plasma membrane permeability of yeast cells under ethanol stress as compared with the control. Meanwhile, high viability levels acquired by the addition of Ca 2+ exactly corresponded to the striking decreases in extracellular nucleotide concentration and P′ achieved with identical approach. Therefore, the enhancing effect of Ca 2+ on ethanol tolerance of this strain is closely related to its ability to decrease plasma membrane permeability of yeast cells subjected to ethanol stress.更多还原