STUDIES ON RAPIDLY FROZEN SUSPENSIONS OF YEAST CELLS BY DIFFERENTIAL THERMAL ANALYSIS AND CONDUCTOMETRY
STUDIES ON RAPIDLY FROZEN SUSPENSIONS OF YEAST CELLS BY DIFFERENTIAL THERMAL ANALYSIS AND CONDUCTOMETRY
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DOI：
10.1016/s0006-3495(63)86824-1
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发表时间：
1963-01-01
影响因子：
3.4
通讯作者：
MAZUR, P
中科院分区：
文献类型：
--
作者：
MAZUR, P
几乎没有酵母细胞能在快速冷却到196摄氏度和随后的缓慢升温中存活下来。快速冷冻后，悬浮液在升温过程中吸收15[degree]和0[degree]C之间的熔化潜热，并且吸收的热量与细胞浓度之间的关系与等效KCl溶液中的关系相同，表明冷冻悬浮液的热行为与冷冻溶液相似。吸收的热量是这样的，超过80%的细胞内溶液必须被冷冻。冷冻悬浮液的电导行为表明，在吸收热量时，细胞溶质仍在细胞内，并被完整的细胞膜包围。两个模型与这些发现是一致的。第一种假设是细胞内已经发生冻结;第二种假设是所有可冻结的水已经离开细胞并在外部冻结。后一种模型被排除，因为快速冷却的电池不会收缩等于必须抽出以防止内部冻结的水的体积。
Few, if any, yeast cells survived rapid cooling to [long dash] 196[degree]C and subsequent slow warming. After rapid freezing, the suspensions absorbed latent heat of fusion between[long dash]15[degree] and 0[degree]C during warming, and the relation between the amount of heat absorbed and the concentrations of cells was the same as that in equivalent KC1 solutions, indicating that frozen suspensions behave thermally like frozen solutions. The amount of heat absorbed was such that more than 80 per cent of the intracellular solution had to be frozen. The conductometric behavior of frozen suspensions showed that cell solutes were still inside the cells and surrounded by an intact cell membrane at the time heat was being absorbed. Two models are consistent with these findings. The first assumes that intracellular freezing has taken place; the second that all freezable water has left the cells and frozen externally. The latter model is ruled out because rapidly cooled cells do not shrink by an amount equal to the volume of water that would have to be withdrawn to prevent internal freezing.