The influence of ribosome modulation factor on the survival of stationary-phase Escherichia coli during acid stress
The influence of ribosome modulation factor on the survival of stationary-phase Escherichia coli during acid stress
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DOI：
10.1099/mic.0.2006/001552-0
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发表时间：
2007-01-01
期刊：
影响因子：
2.8
通讯作者：
Niven, Gordon W.
中科院分区：
文献类型：
--
作者：
El-Sharoud, Walid M.;Niven, Gordon W.
由于缺乏核糖体调节因子(RMF)的突变菌株在pH值为3的条件下培养物的活力比亲本菌株下降得更快，因此在稳定期的酸性胁迫下，核糖体调节因子(RMF)对大肠杆菌的存活有影响。在低pH条件下，两种菌株都观察到核糖体的丢失，但RMF缺失的突变菌株这种情况发生的速度更快，它也遭受了更高的rRNA降解水平。结论：RMF在限制rRNA损伤方面的作用有助于保护酸胁迫下的大肠杆菌。在酸化条件下生长后的稳定期，RMF基因的表达比不加酸时低，而且在酸化条件下，从指数期向稳定期转变所引起的RMF表达的增加也大大减少。研究表明，RMF不参与大肠杆菌的静止相耐酸反应，在酸性条件下生长可保护其免受随后的酸休克。这一反应足以克服RMF缺失突变株在pH值在6.5至5.5之间时对酸胁迫的脆弱性增加。
Ribosome modulation factor (RMF) was shown to have an influence on the survival of Escherichia coli under acid stress during stationary phase, since the viability of cultures of a mutant strain lacking functional RMF decreased more rapidly than that of the parent strain at pH 3. Loss of ribosomes was observed in both strains when exposed to low pH, although this occurred at a higher rate in the RMF-deficient mutant strain, which also suffered from higher levels of rRNA degradation. It was concluded that the action of RMF in limiting the damage to rRNA contributed to the protection of E coli under acid stress. Expression of the rmf gene was lower during stationary phase after growth in acidified media compared to media containing no added acid, and the increased rmf expression associated with transition from exponential phase to stationary phase was much reduced in acidified media. It was demonstrated that RMF was not involved in the stationary-phase acid-tolerance response in E coli by which growth under acidic conditions confers protection against subsequent acid shock. This response was sufficient to overcome the increased vulnerability of the RMF-deficient mutant strain to acid stress at pH values between 6.5 and 5.5.