渗透剂对酿酒酵母细胞增殖、形态和存活力的影响

为了揭示渗透作用机制，考察了氯化钠、山梨醇、甘油和聚乙二醇（PEG600）等4种化合物对模式生物S. cerevisiae细胞生长、形态结构和代谢的影响.24 h细胞培养结果表明，渗透剂的抑制作用与其浓度的增加一致，细胞的比生长速率下降.高渗环境使细胞形态发生改变，趋于球状.细胞生长动力学表明，0.5 mol•L^-1氯化钠显著延缓耗糖速率，降低比生长速率，延长细胞指数生长期；0.33 mol•L^-1PEG600对指数生长期的细胞无显著影响，但缩短了细胞平衡期.在生理可接受的渗透强度内，与对照组相比较，0.5 mol•L^-1氯化钠和0.33 mol•L^-1PEG600不影响最终残糖水平和生物量浓度.

INFLUENCES OF OSMOLYTES ON CELLULAR PROLIFERATION, MORPHOLOGY AND VIABILITY OF Saccharomyces cerevisiae

Much attention has been paid to the influences of osmosis on Saccharomyces cerevisiae, due to the increasing application in the food and pharmaceutical industries, biotransformations. Besides, to maintain an appropriate turgor is of crucial importance to individual growth, cellular division and viability.In the study, to evaluate the impacts of different osmolytes on cellular proliferation, morphology and viability of the model microbe Saccharomyces cerevisiae FL 1, in additon to the commonly used sodium chloride, glycerol, poly(ethyleneglycol)600, and sorbitol were used.Moreover, the dynamic behavior of cell proliferation and metabolism under physiologicallg acceptable hyperosmotic condition were examined. Results indicated that these osmolytes had significant negative impacts on proliferation with increasing concentration, compared to the control treatment composed of YEPD media. The cellular morphology was close to sphere after exposure to high osmotic pressure for 24 h. After analyzing the dynamics data, sodium chloride of 0.5 mol•L^-1 was found to markedly reduce the specific cell growth rate, sugar consumption but prolong the duration of exponential growth phase. At the same time, PEG600 of 0.33 mol•L^-1 had no marked influence on cell proliferation but shortened the stationary phase.However, under the physiologically acceptable hyperosmotic condition, the final biomass density among all the treatments was similar.