渗透压突然改变对大肠埃希菌水通道蛋白GlpF基因表达的影响

目的 探讨水-甘油通道蛋白(glycerol protein ficilitator,GlpF)的生理功能及对细菌生长繁殖的影响.方法 将大肠埃希菌接种于等渗透压的液体培养基(1 IM)培养,18h后,突然改变培养液的渗透压,在30、60、120 min时间点检测细菌的A600nm值,RT-PCR分析其GlpF的表达.结果 突然改变渗透压后,大肠埃希菌数量均有不同程度的减少.在1/2 IM组、1/4 IM组细菌的A600nm值与其各自对照组相比,变化并不明显,但其细菌GlpF表达量明显降低.在高渗组,2 IM组的A600nm值与等渗组相比变化不大,而其GlpF表达量明显高于等渗组.结论 在环境渗透压突然改变时,细菌可以通过调控GlpF的表达来实现对细菌细胞内外水份的调节,以维持胞内环境稳定.

The effect on the expression of aquaporin gene GlpF of Escherichia coli when the osmotic pressure changes suddenly

Objective To explore the physiological function and the effect of glycerol protein ficilitator（GlpF） on the growth and multiplication of Escherichia coll. Methods The E. coli was inoculated in liquid culture medium of osmotic pressure and cultured for18 hours. A600 nm values of E. coli were detected and the expressions of GlpF were analyzed by RT-PCR when the osmotic pressure was changed suddenly after 30 min, 60 mins and 120 mins. Results The number of E. coli decreased in different degrees after sudden change of osmotic pressures. Comparing with their respective control group, the change of A600nm value in 1/2 IM （isotonic medium） group and 1/4 IM group were not obvious, but the expressions of GlpF were reduced significantly. In the hypertonic group, A600 nm value in 2 IM group changed little comparing with isotonic group, but the expressions of GlpF were increased significantly. Conclusion When osmotic pressures in the environment were suddenly changed, bacteria can regulate the expression of GlpF to achieve the balance of water inside and outside the bacterial cells to maintain intracellular homeostasis.