The Na+/H Anthiporters of Alkaliphilic Bacillus firmus OF4 and of Bacillus subtilis

嗜碱性芽孢杆菌 OF4 和枯草芽孢杆菌的 Na /H 反转运蛋白

• 批准号: 9303183
• 负责人: Terry Krulwich
• 金额: $ 28.04万
• 依托单位: Icahn School of Medicine at Mount Sinai
• 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: 1993-07-15 至 1996-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9303183&HistoricalAwards=false
• 关键词: Na+; Anthiporters; Alkaliphilic; Bacillus; firmus

9303183 Krulwich Bacillus firmus OF4 is an extreme alkaliphile that can grow well over a pH range from 7.5 to 10.7, and is also capable of growth over a range of Na+ concentrations from mM to 1M. This bacterium lacks primary Na+ extrusion mechanisms and apparently requires electrogenic Na+/H+ antiporters for both pH homeostasis and Na+ tolerance. Na+/H+ antiporter-deficient mutants have been isolated from Bacillus subtilis, taking advantage of Tn917 mutagenesis, in order to develop system for heterologous screening and expression of alkaliphile genes, and for comparative study of a neutralophilic Bacillus. Using this system, and Tn916 insertional mutagenesis of the alkaliphile itself, attempts are being made to identify the remaining alkaliphile Na+/H+ antiporter gene (s) and possibly, regulators thereof. The relationship between each detailed characterization will be undertaken of the Na+/H+ antiporter that has the dominant role in pH homeostasis. The basis for the alkaliphile's generation of genetic variants will be studied. Such variants have the capacity for enhanced growth at the upper edge of their pH range and at suboptimal Na+ concentration. They have previously shown to exhibit an increase in the already high constitutive Na+/H+ antiporter activity. %%% This research will provide an understanding of how microorganisms can grow under conditions of extreme pH and sodium variance. This could lead to applications such as bioremediation under circumstances where it is currently not proactical because organisms with the desired metabolic capabilities cannot grow due to their sensitivity to strong basic environments. ***

9303183 Krulwich坚强芽孢杆菌OF 4是一种极端嗜碱菌，能在pH 7.5 - 10.7范围内生长良好，也能在Na+浓度mM-1 M范围内生长。 这种细菌缺乏主要的Na+挤出机制，显然需要产电Na+/H+反向转运蛋白的pH稳态和Na+耐受。 利用Tn 917诱变技术，从枯草芽孢杆菌（Bacillussubtilis）中分离得到Na+/H+反向转运蛋白缺陷突变株，为嗜碱基因的异源筛选和表达以及嗜中性芽孢杆菌的比较研究奠定了基础。 使用该系统和亲碱菌本身的Tn 916插入诱变，尝试鉴定剩余的亲碱菌Na+/H+反向转运蛋白基因和可能的其调节物。 每个详细的表征之间的关系将进行的Na+/H+逆向转运蛋白，具有主导作用的pH稳态。 将研究嗜碱菌产生遗传变异的基础。 这种变体具有在其pH范围的上边缘和次优Na+浓度下增强生长的能力。 它们先前已经显示出在已经很高的组成型Na+/H+反向转运蛋白活性中表现出增加。 这项研究将提供微生物如何在极端pH值和钠变化条件下生长的理解。 这可能会导致应用，如生物修复的情况下，它是目前没有proactical，因为生物体与所需的代谢能力不能生长，由于其敏感性强的碱性环境。 ***