环境因素对σ因子表达水平的影响

THE EFFECTS OF SURROUNDINGS ON σ FACTORS EXPRESSION LEVEL

在不同的生长时间、NaCl浓度、pH值、温度等条件下培养W335 0菌株。菌体裂解液经SDS -PAGE分离 ,电转移至硝酸纤维素膜。利用Western -blotting检测各种条件下大肠杆菌RNA聚合酶结的构亚基σ因子的表达水平。计算机分析结果表明 :σ70 在本实验条件下变化不大 ;而σ3 8在进入稳定期后胞内含量是对数期的 3倍以上 ;热休克后其浓度升高 ;在加入 0 5mol/LNaCl后刺激 30min ,σ3 8胞内浓度达到最大值 ;不同 pH培养条件下细胞内σ3 8因子的浓度无明显差异 ,但酸性条件下的表达水平略高于碱性条件。由细胞内σ因子表达水平的变化可以推知 :σ3 8不仅是大肠杆菌稳定生长期的重要调节因子 。

A strain of E.coli W3350 was cultured in different time,NaCl concentration , pH and temperature. Western blotting was employed for measuring σfactor. The strip was scanned and analyzed by computer. The results showed that σ+{70} was not the only important factor in the stationary growth phase by also a overall regulator in E.coli.