Meury J, Kohiyama M
Institut Jacques Monod, Paris, France.
J Bacteriol. 1991 Jul;173(14):4404-10. doi: 10.1128/jb.173.14.4404-4410.1991.
Escherichia coli can adapt and recover growth at high osmolarity. Adaptation requires the deplasmolysis of cells previously plasmolyzed by the fast efflux of water promoted by osmotic upshift. Deplasmolysis is essentially ensured by a net osmo-dependent influx of K+. The cellular content of the heat shock protein DnaK is increased in response to osmotic upshift and does not decrease as long as osmolarity is high. The dnaK756(Ts) mutant, which fails to deplasmolyze and recover growth, does not take up K+ at high osmolarity; DnaK protein is required directly or indirectly for the maintenance of K+ transport at high osmolarity. The temperature-sensitive mutations dnaJ259 and grpE280 do not affect the osmoadaptation of E. coli at 30 degrees C.
大肠杆菌能够在高渗透压环境下适应并恢复生长。适应过程需要先前因渗透压升高导致水分快速外流而发生质壁分离的细胞去质壁分离。去质壁分离主要通过钾离子的净渗透依赖性内流来确保。热休克蛋白DnaK的细胞含量会因渗透压升高而增加，并且只要渗透压保持在高水平就不会降低。dnaK756（Ts）突变体无法去质壁分离并恢复生长，在高渗透压下不摄取钾离子；DnaK蛋白对于在高渗透压下维持钾离子转运直接或间接是必需的。温度敏感突变体dnaJ259和grpE280在30摄氏度时不影响大肠杆菌的渗透适应。
