THE ACID TOLERANCE RESPONSE OF SALMONELLA-TYPHIMURIUM INVOLVES TRANSIENT SYNTHESIS OF KEY ACID SHOCK PROTEINS
THE ACID TOLERANCE RESPONSE OF SALMONELLA-TYPHIMURIUM INVOLVES TRANSIENT SYNTHESIS OF KEY ACID SHOCK PROTEINS
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DOI：
10.1128/jb.175.7.1981-1987.1993
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发表时间：
1993-04-01
影响因子：
3.2
通讯作者：
FOSTER, JW
中科院分区：
文献类型：
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作者：
FOSTER, JW
虽然鼠伤寒沙门氏菌喜欢中性pH环境，但它可以适应严重低pH应激（pH 3.3）的生存条件。这个过程被称为耐酸性反应（ATR），包括两个不同的阶段。第一阶段称为酸休克前，在pH 5.8下诱导，并涉及在外部pH值低于4.0时产生可诱导的pH稳态系统。第二阶段发生在酸休克转变至pH 4.5或更低之后，称为酸休克后阶段。在ATR的这个阶段，合成了43种酸休克蛋白（ASP）。目前的数据表明，几个ASP的pH值3.3的耐酸性重要的只是短暂的生产。它们在pH 4.4的酸休克30至40分钟后消失，与随后的pH 3.3的酸挑战无法存活一致。显然，诱导型耐酸性的一个基本特征是合成这些关键ASP的能力。前酸休克阶段，其诱导的pH稳态系统，提供了一个增强的能力，细胞合成ASP后迅速转变到低于pH 4.0的条件下，外部pH值，通常会阻止ASP的合成。该数据还解决了ASP合成的可能信号。22个ASP的诱导信号似乎是内部酸化，而外部pH值用于诱导其他13个。在14种瞬时ASP中，10种是响应于内部pH的变化而诱导的。产生Atr酸敏感表型的毛皮（铁摄取调节剂）基因座中的突变也消除了6种瞬时诱导ASP的诱导。
Although Salmonella typhimurium prefers neutral-pH environments, it can adapt to survive conditions of severe low-pH stress (pH 3.3). The process, termed the acid tolerance response (ATR), includes two distinct stages. The first stage, called pre-acid shock, is induced at pH 5.8 and involves the production of an inducible pH homeostasis system functional at external pH values below 4.0. The second stage occurs following an acid shock shift to pH 4.5 or below and is called the post-acid shock stage. During this stage of the ATR, 43 acid shock proteins (ASPs) are synthesized. The present data reveal that several ASPs important for pH 3.3 acid tolerance are only transiently produced. Their disappearance after 30 to 40 min of pH 4.4 acid shock coincides with an inability to survive subsequent pH 3.3 acid challenge. Clearly, an essential feature of inducible acid tolerance is an ability to synthesize these key ASPs. The pre-acid shock stage, with its inducible pH homeostasis system, offers the cell an enhanced ability to synthesize ASPs following rapid shifts to conditions below pH 4.0, an external pH that normally prevents ASP synthesis. The data also address possible signals for ASP synthesis. The inducing signal for 22 ASPs appears to be internal acidification, while external pH serves to induce 13 others. Of the 14 transient ASPs, 10 are induced in response to changes in internal pH. Mutations in the fur (ferric uptake regulator) locus that produce an Atr- acid-sensitive phenotype also eliminate induction of six transiently induced ASPs.