COLD-SHOCK AND CHILLING TOLERANCE IN DROSOPHILA
COLD-SHOCK AND CHILLING TOLERANCE IN DROSOPHILA
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DOI：
10.1016/0022-1910(94)90093-0
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发表时间：
1994-08-01
影响因子：
2.2
通讯作者：
WALKER, VK
中科院分区：
文献类型：
--
作者：
CHEN, CP;WALKER, VK
研究了黑腹果蝇成虫对直接（冷休克）和间接冷伤的耐受性。低温下死亡率呈指数增长。在4℃和0℃的低温耐受性（T-ch）分别为6.3天和37.91 h， 50%存活率（LT(50)），而T-cs在-7℃的冷激耐受性（LT(50)）仅为1.5 h。在4℃或0℃驯化后，-7℃的冷激耐受性（T-cs）迅速增加：与驯化获得的最高LT（50）相比，LT（50）仅在2小时内增加了约50%。从评估T-ch和T-cs的实验数据中计算出了一个平衡点（T-eq），即低温和/或冷休克最大存活的最佳驯化时间。T-eq为在低温下导致90%死亡率的驯化期（LT(90)）的一半时间。对冷休克或低温耐受性的选择经过几代分别导致T-cs或T-ch显著增加。冷选系的糖原和总蛋白含量高于对照系。暴露在低温下最终耗尽了能量储备，但在驯化时间观察到最高浓度的甘油三酯和蛋白质，最高的T-cs。这表明，这些能量储备的系统调节可能是冷硬化机制的重要组成部分，以应对低温波动引起的冷休克或冷伤。
Adult flies of Drosophila melanogaster were examined for their tolerance to direct (cold-shock) and indirect chilling (chilling) injury. An exponential increase in mortality with low temperatures occurs. Chilling tolerance (T-ch) at 4 or 0 degrees C was 6.3 days or 37.91 h for 50% survival (LT(50)), respectively, while the cold-shock tolerance (LT(50) of T-cs) at -7 degrees C was only 1.5 h. The increase in cold-shock tolerance (T-cs) at -7 degrees C by acclimation at 4, or 0 degrees C was rapid: the LT(50) increased about 50% with only 2 h of treatment in comparison with the highest LT(50) obtained by acclimation. An equilibrium point (T-eq), the optimal acclimation time for maximal survival of chilling and/or cold-shock, was calculated from the survival data of experiments designed to assess T-ch and T-cs The T-eq was found to be the half time of the acclimation period which resulted in 90% mortality at the chilling temperature (LT(90) of T-ch). Selection for tolerance to cold-shock or chilling over several generations resulted in a significant increase in T-cs or T-ch, respectively. Higher contents of glycogen and total proteins were observed in the cold selected lines than in the control line. Exposure to chilling temperatures eventually depleted the energy reserves, but the highest concentrations of triacylglycerols and proteins were observed at the acclimation time with the highest T-cs. This suggests that systemic regulation in these energetic reserves may be an important part of the cold-hardening mechanisms to cope with the fluctuations of low temperatures causing cold-shock or chilling injury.