WATER-PERMEABILITY OF YEAST-CELLS AT SUB-ZERO TEMPERATURES
WATER-PERMEABILITY OF YEAST-CELLS AT SUB-ZERO TEMPERATURES
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DOI：
10.1007/bf01961376
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发表时间：
1979-01-01
影响因子：
2.4
通讯作者：
CRAVALHO, EG
中科院分区：
文献类型：
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作者：
LEVIN, RL;USHIYAMA, M;CRAVALHO, EG
采用低温显微镜-多元非线性回归分析相结合的方法测定了冷冻过程中酿酒酵母细胞的透水性。过冷酵母细胞的体积变化的时间速率使用低温显微镜进行电化学监测，所述低温显微镜能够以可编程的方式控制所研究的细胞悬浮液的温度和温度变化的时间速率。多元非线性回归分析与冷冻过程中的细胞水运输的热力学模型，然后用统计推断的细胞水渗透率的零下温度依赖性。S.在零度以下温度下冷却的酿酒酵母受到水通过质膜、细胞壁或这两种渗透性屏障的组合的速率限制。酵母在20 ℃时的水力水渗透系数为0.001。C约为1-2 ×如果允许从零度以下温度外推到室温，则为10-13 cm 3/dynes，而在零度以下温度下控制渗透过程的表观活化能约为45-68 kj/mol（11-16 kcal/mol）。
A combined cryomicroscopic-multiple nonlinear regression analysis technique was used to determine the water permeability of the yeast cell Saccharomyces cerevisiae during freezing. The time rate of change in volume of supercooled yeast cells was photographically monitored using a cryomicroscope which is capable of controlling in a programmable manner the temperature and the time rate of change in temperature of the cell suspension being studied. Multiple nonlinear regression analysis together with a thermodynamic model of cell water transport during freezing was then used to statistically deduce the subzero temperature dependence of the cell water permeability. The water permeability process for S. cerevisiae being cooled at subzero temperatures was rate-limited by the passage of water through either the plasmalemma, the cell wall, or a combination of these 2 permeability barriers. The hydraulic water permeability coefficient for yeast at 20.degree. C is approximately 1-2 .times. 10-13 cm3/dynes if extrapolation from subzero temperatures to room temperature is permissible, while the apparent activation energy governing the permeability process at subzero temperatures is approximated 45-68 kj/mol (11-16 kcal/mol).