Acid-shock responses in Staphylococcus aureus investigated by global gene expression analysis
Acid-shock responses in Staphylococcus aureus investigated by global gene expression analysis
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DOI：
10.1099/mic.0.2007/005942-0
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发表时间：
2007-07-01
期刊：
影响因子：
2.8
通讯作者：
Holck, Askild
中科院分区：
文献类型：
--
作者：
Bore, Erlend;Langsrud, Solveig;Holck, Askild
总体概述了食品致病菌株金黄色葡萄球菌 50583 指数生长培养物酸化至 pH 4.5 后前 20 分钟内基因表达沿时间曲线的变化。使用新开发的统计显着性检验方法来检测显着的基因表达反应。大多数反应显示酸化后从零到 10 分钟的时间增加或减少，然后通常在 10 到 20 分钟表达水平稳定。脲酶活性的增加似乎是酸防御的一个重要因素，此外还有 NADH 脱氢酶的质子排泄和大分子修复机制。还诱导了氧化应激反应，例如硫氧还蛋白基因表达增加和磷酸戊糖途径基因上调以产生更多还原能力。编码核糖体蛋白的基因和参与核苷酸合成以及脂肪酸和脂蛋白代谢的基因的表达普遍减少，反映了酸化后生长速率的降低。 pH 冲击似乎不会引发主要的毒力反应或生物膜形成。金属离子的调节和运输受到酸休克的影响，并且钼蝶呤等几种辅助因子的产生增加。所提出的许多观察结果都可以得到解释，而有些则代表仍然未知的机制。通过定量逆转录酶 PCR (ORT-PCR) 证实了调控模式。总之，这些结果显示了金黄色葡萄球菌的主要反应，并将成为未来对与金黄色葡萄球菌酸应激防御相关的特定基因反应进行更具体、深入研究的良好起点。
A general overview is presented of the changes in the genetic expression along a time curve through the first 20 min after acidification to pH 4.5 of exponentially growing cultures of the food pathogenic strain Staphylococcus aureus 50583. A newly developed method for statistical significance testing was used to detect significant gene expression responses. Most responses showed an increase or decrease from time zero to 10 min after acidification, and then generally a stabilization in expression level from 10 to 20 min. Increased urease activity appeared to be an important factor in the acid defence, along with proton excretion by NADH dehydrogenase and macromolecule repair mechanisms. Oxidative-stress responses, such as increased expression of thioredoxin genes and upregulation of pentose phosphate pathway genes to generate more reducing power, were also induced. A general reduction in the expression of genes encoding ribosomal proteins and genes involved in nucleotide synthesis, as well as fatty acid and lipoprotein metabolism, reflected the lowered growth rate after acidification. The pH shock did not appear to trigger major virulence responses or biofilm formation. Metal ion regulation and transport were affected by the acid shock, and production of several cofactors such as molybdopterin was increased. Many of the presented observations could be explained, while some represent still-unknown mechanisms. The patterns of regulation were confirmed by quantitive reverse transcriptase PCR (ORT-PCR). Together, these results showed the main responses of S. aureus and will be a good starting point for future, more specific, in-depth studies of specific gene responses that occur in conjunction with the acid-stress defence of S. aureus.