Raja N, Goodson M, Chui W C, Smith D G, Rowbury R J
Department of Biology, University College London, UK.
J Appl Bacteriol. 1991 Jan;70(1):59-65. doi: 10.1111/j.1365-2672.1991.tb03787.x.
Induction of acid resistance (habituation) in Escherichia coli at pH 5.0 took ca 5 min in broth at 37 degrees C and 30-60 min in minimal medium. Induction occurred at a range of pH values from 4.0 to 6.0; it was dependent on continuing protein and RNA synthesis but substantial acid resistance appeared in the presence of nalidixic acid. Acid resistance was long-lasting; organisms grown at pH 5.0 retained most of their resistance after 2 h growth at pH 7.0. Organisms grown at pH 5.0 showed increased synthesis of a number of cytoplasmic proteins compared with the level in cells grown at pH 7.0. DNA repair-deficient strains carrying recA, uvrA or polA1 mutations were more acid-sensitive than the repair-proficient parents but were able to habituate at pH 5.0. Organisms grown at pH 5.0 transferred the ColV plasmid much more effectively at acid pH than did those grown at pH 7.0 and habituated recipients appeared better able to repair incoming acid-damaged plasmid DNA than did those that were non-habituated. Induction of acid resistance at pH 5.0 may be significant for the survival of organisms exposed to periodic discharges of acid effluent in the aquatic environment and habituation may also allow plasmid transfer and repair of acid-damaged plasmid DNA during or after such exposure.
在37摄氏度的肉汤中，大肠杆菌在pH 5.0条件下诱导产生耐酸性（适应性）大约需要5分钟，而在基本培养基中则需要30 - 60分钟。在pH值为4.0至6.0的范围内均可发生诱导；这依赖于持续的蛋白质和RNA合成，但在萘啶酸存在的情况下仍会出现显著的耐酸性。耐酸性具有持久性；在pH 5.0条件下生长的菌体在pH 7.0条件下生长2小时后仍保留大部分抗性。与在pH 7.0条件下生长的细胞相比，在pH 5.0条件下生长的菌体显示出多种细胞质蛋白的合成增加。携带recA、uvrA或polA1突变的DNA修复缺陷型菌株比修复能力正常的亲本对酸更敏感，但仍能在pH 5.0条件下适应。在酸性pH条件下，在pH 5.0条件下生长的菌体比在pH 7.0条件下生长的菌体更有效地转移ColV质粒，而且适应后的受体似乎比未适应的受体更能修复进入的酸损伤质粒DNA。在pH 5.0条件下诱导产生耐酸性对于暴露于水生环境中周期性排放酸性废水的生物体的存活可能具有重要意义，并且适应性还可能允许在这种暴露期间或之后进行质粒转移以及修复酸损伤的质粒DNA。
