Intracellular ice formation in yeast cells vs. cooling rate: predictions from modeling vs. experimental observations by differential scanning calorimetry.
Intracellular ice formation in yeast cells vs. cooling rate: predictions from modeling vs. experimental observations by differential scanning calorimetry.
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DOI：
10.1016/j.cryobiol.2008.11.011
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发表时间：
2009-04
期刊：
影响因子：
2.7
通讯作者：
Mazur, Peter
中科院分区：
文献类型：
--
作者：
Seki, Shinsuke;Kleinhans, F. W.;Mazur, Peter
为了在冷冻中存活，细胞在冷却过程中不能经历内部冰的形成。一个重要因素是冷却速度。细胞冷却得越快，其内容物越冷，在零度以下的温度下，过冷的细胞质将冻结。问题是在什么温度下？计算了冷却速率与电池过冷度的关系。两个重要参数是水渗透率（Lp）及其温度依赖性。为了避免细胞内冰形成（IIF），必须在细胞冷却到其冰成核温度之前通过脱水来消除过冷。在观察到的成核温度为−25°C的情况下，模型预测IIF不应该发生在以<20°C/min冷却的酵母中，而应该几乎肯定发生在以≥ 30°C/min冷却的细胞中。DSC的前提是，如果没有IIF，人们应该只能看到一个代表外部水冻结的单点。如果IIF发生，人们应该看到第二个温度较低的温度梯度。第二种模式是否是IIF的进一步测试是它是否在反复冷冻时消失。IIF破坏了质膜;因此，在随后的冷冻循环中，细胞不再过冷，也不会表现出第二次冷冻。这证明在冷却速率> 20°C/min的情况下是如此。
To survive freezing, cells must not undergo internal ice formation during cooling. One vital factor is the cooling rate. The faster cells are cooled, the more their contents supercool, and at some subzero temperature that supercooled cytoplasm will freeze. The question is at what temperature? The relation between cooling rate and cell supercooling can be computed. Two important parameters are the water permeability (Lp) and its temperature dependence. To avoid intracellular ice formation (IIF), the supercooling must be eliminated by dehydration before the cell cools to its ice nucleation temperature. With an observed nucleation temperature of −25°C, the modeling predicts that IIF should not occur in yeast cooled at <20°C/min and it should occur with near certainty in cells cooled at ≥ 30°C/min. Experiments with differential scanning calorimetry (DSC) confirmed these predictions closely. The premise with the DSC is that if there is no IIF, one should see only a single exotherm representing the freezing of the external water. If IIF occurs, one should see a second, lower temperature exotherm. A further test of whether this second exotherm is IIF is whether it disappears on repeated freezing. IIF disrupts the plasma membrane; consequently, in a subsequent freeze cycle, the cell can no longer supercool and will not exhibit a second exotherm. This proved to be the case at cooling rates > 20°C/min.
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DOI：
10.1083/jcb.57.3.729
发表时间：
1973-06
期刊：
The Journal of cell biology
影响因子：
--
作者：
Bank H;Mazur P
通讯作者：
Mazur P
影响因子：
3.4
作者：
MAZUR, P
通讯作者：
MAZUR, P
影响因子：
3.4
作者：
MAZUR, P
通讯作者：
MAZUR, P
影响因子：
2.4
作者：
LEVIN, RL;USHIYAMA, M;CRAVALHO, EG
通讯作者：
CRAVALHO, EG
影响因子：
2.7
作者：
BRYANT, G
通讯作者：
BRYANT, G