Ono T A, Murata N
Department of Biology, University of Tokyo, Komaba, Meguro-ku, Tokyo 153, Japan.
Plant Physiol. 1981 Jan;67(1):182-7. doi: 10.1104/pp.67.1.182.
Potassium ions and amino acids were found to leak from the cytoplasm to the outer medium when the blue-green alga, Anacystis nidulans, was exposed to the chilling temperatures. The leakage was marked below the critical temperature regions, the midpoint values for which were around 5 and 14 C in cells grown at 28 and 38 C, respectively. These temperature regions coincided with those critical for the susceptibility of the photosynthetic activities and the carotenoid absorption spectrum previously studied (Ono TA, N Murata 1981 Plant Physiol 67: 176-181).Potassium and magnesium ions in the cell suspension medium protected the algal cells from the chilling-induced damage of the Hill reaction with 1,4-benzoquinone. The activity of the Hill reaction which had been diminished by the first chilling treatment in a low salt medium was restored by the second chilling treatment of a high salt medium. The chilling susceptibility of the Hill reaction could be attributed to the leakage of cations from the cytoplasm due to increased permeability of the cytoplasmic membrane at the chilling temperatures.A mechanism is proposed to interpret the chilling susceptibility of A. nidulans: (a) at chilling temperatures, the bilayer lipids of the cytoplasmic membrane are in the phase separation state; (b) ions and solutes having low molecular weights leak from the cytoplasm to the outer medium when the lipids of the cytoplasmic membrane are in the phase separation state; (c) decreases in the intracellular concentrations of ions and solutes degrade the physiological activities of the cells.
当蓝藻集胞藻(Anacystis nidulans)暴露于低温时,发现钾离子和氨基酸会从细胞质泄漏到外部介质中。在临界温度区域以下,这种泄漏很明显,对于分别在28℃和38℃下生长的细胞,其临界温度区域的中点值分别约为5℃和14℃。这些温度区域与先前研究的光合作用活性和类胡萝卜素吸收光谱的敏感性临界温度区域一致(Ono TA,N Murata 1981植物生理学67:176 - 181)。细胞悬浮培养基中的钾离子和镁离子保护藻类细胞免受1,4 - 苯醌对希尔反应的冷诱导损伤。在低盐培养基中首次冷处理后降低的希尔反应活性,通过在高盐培养基中的第二次冷处理得以恢复。希尔反应的冷敏感性可归因于在低温下细胞质膜通透性增加导致阳离子从细胞质泄漏。提出了一种机制来解释集胞藻的冷敏感性:(a)在低温下,细胞质膜的双层脂质处于相分离状态;(b)当细胞质膜的脂质处于相分离状态时,低分子量的离子和溶质从细胞质泄漏到外部介质中;(c)细胞内离子和溶质浓度的降低会降低细胞的生理活性。