Acid Resistance and Stationary Phase in Escherichia coli andShigella flexneri

大肠杆菌和福氏志贺氏菌的耐酸性和固定相

• 批准号: 9305354
• 负责人: Joan Slonczewski
• 金额: $ 29.3万
• 依托单位: Kenyon College
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-09-01 至 1997-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9305354&HistoricalAwards=false
• 关键词: Acid; Resistance; Stationary; Phase; Escherichia

9305354 Slonczewski The genetic mechanisms of resistance to extreme acid and of pH homeostasis is being investigated in Escherichia coli and its close relative Shigella flexneri. Genes have been identified which are required for stationary-phase induction of resistance to extreme acid (pH 2-3). These include katF and several Tn5 insertions of unknown location. The following questions are being addressed: What are the roles of pH and anaerobiosis is stationary-phase acid resistance? Which gene products participate in acid resistance, and how are they regulated? Do some acid-resistance loci also participate in pH homeostasis during growth? Does stationary phase also confer alkaline resistance response? The objectives are: observe pH dependence, if any, of stationary-phase acid resistance; measure pHint homeostasis and pH-dependent growth of acid-sensitive strains; screen E. coli Tn10 and lac fusion strains for acid- sensitivity, and map the loci; characterize stationary-phase alkaline resistance in E. coli. %%% pH is a major environmental parameter for bacteria, and internal pH is significant in terms of bacterial physiology and energy transduction . This research will lead to an understanding of how bacteria can survive and function in extremely acidic environments. ***

9305354 SLonczewski目前正在研究大肠杆菌及其近亲福氏志贺氏菌对极端酸性的抗性和pH动态平衡的遗传机制。已经确定了在固定相诱导对极端酸性(pH 2-3)的抗性所需的基因。其中包括Katf和几个未知位置的Tn5插入。以下问题正在被解决：pH值和厌氧菌在固定相耐酸中起什么作用？哪些基因产物参与耐酸，它们是如何调节的？生长过程中是否也有一些耐酸基因参与pH动态平衡？固定相是否也具有耐碱性反应？其目的是：观察固定相耐酸性的pH依赖性(如果有的话)；测量酸敏菌株的PHINT动态平衡和pH依赖性生长；筛选E.coliTn10和lac融合菌株的酸敏性，并定位；表征大肠杆菌的固定相耐碱性。%pH是细菌的主要环境参数，其内部pH在细菌生理和能量传递方面具有重要意义。这项研究将有助于理解细菌如何在极端酸性环境中生存和发挥作用。***