ROLE OF AN ESCHERICHIA-COLI STRESS-RESPONSE OPERON IN STATIONARY-PHASE SURVIVAL
ROLE OF AN ESCHERICHIA-COLI STRESS-RESPONSE OPERON IN STATIONARY-PHASE SURVIVAL
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DOI：
10.1073/pnas.91.6.2191
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发表时间：
1994-03-15
影响因子：
11.1
通讯作者：
MODEL, P
中科院分区：
文献类型：
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作者：
WEINER, L;MODEL, P
大肠杆菌噬菌体休克蛋白操纵子(PspABCE)在热休克、乙醇处理、渗透压休克和丝状噬菌体感染等应激环境条件下强烈表达。我们发现，缺乏pspABC基因的细菌在碱性条件下(pH为9)的静止相中长期孵育的生存能力显著下降。PSP突变菌在碱性条件下的生长情况与野生型相近，当pH值接近最适生长范围(pH 6-8)时，PSP突变菌的静止相存活率显著提高。在静止期晚期(出生1-2天)的细胞中，操纵子在一定条件下可以被强烈诱导，PSPA可以成为最高表达的细菌蛋白之一。固定相饥饿和碱性pH的组合可能会对内源能源的维持造成严重的压力，与这些影响一致的是，我们发现PSP的表达也是由氧化磷酸化的解偶联剂和其他干扰能量产生的试剂诱导的。在相同的培养条件下，野生型细菌的存在加速了PSP突变体在稳定期的死亡率，这表明PSP操纵子可能在使大肠杆菌在营养或能量有限的条件下竞争生存方面发挥重要作用。
The phage shock protein operon (pspABCE) of Escherichia coli is strongly expressed in response to stressful environmental conditions, such as heat shock, ethanol treatment, osmotic shock, and filamentous phage infection. We show that bacteria lacking the pspABC genes exhibit a substantial decrease in the ability to survive prolonged incubation in stationary phase under alkaline conditions (pH 9). The psp mutant bacteria grow approximately as well as wild-type strains in the alkaline medium, and stationary-phase survival of the psp mutants improves substantially at pH values closer to the optimal growth range (pH 6-8). In late stationary-phase (1- to 2-day-old) cells, the operon can be strongly induced under certain conditions, and PspA can become one of the most highly expressed bacterial proteins. The combination of stationary-phase starvation and alkaline pH is likely to place a severe strain on the maintenance of endogenous energy sources, and, consistent with these effects, we find that psp expression is also induced by uncouplers of oxidative phosphorylation and other agents that interfere with energy production. The death rate of psp mutants in stationary phase is accelerated by the presence of wild-type bacteria in the same culture, suggesting that the psp operon may play a significant role in enabling E. coli to compete for survival under nutrient- or energy-limited conditions.