Analyses of sodium bioenergetics in Vibrio cholerae

所有活细胞都在初级离子泵的帮助下建立跨膜电化学梯度。 初级Na+泵已在相当不同的产碱类群的许多微生物中发现， Na+离子的跨膜循环可能在几种细菌的生理学中起重要作用。 最近完成的许多细菌基因组序列揭示了编码一种 许多生物体中的各种钠依赖系统，包括一些不知道有钠依赖系统的生物。 钠的能量循环这表明这些细菌可以利用Na+作为耦合离子， 或者说，除了H+循环之外。尽管人们对钠的能量循环在体内的作用知之甚少， 在霍乱弧菌的生理学中，存在大量的钠依赖性系统编码在霍乱弧菌中。 这种生物的基因组值得研究其各种Na+泵。在本申请中， 构建和分析霍乱弧菌Na+-挤出酶的确定突变体作为模式生物， 进一步了解细菌生理学中这一非常复杂和重要的部分。我们提出了一个 对细菌钠生物能量学的组分进行全面和系统的分析 通过使用广泛的基因操作与复杂的生物能量测量相结合。 拟议研究的结果不仅将增强我们对一般生物能量途径的理解， 在细菌中，但将形成一个坚实的基础，为未来的调查，由我们自己和他人，的分子 维持微生物中离子稳态的装置。钠生物能量学可能在这两个方面都起作用 霍乱弧菌生命周期的环境和致病阶段。因此，我们的研究有可能 用于产生与细菌生理学相关的基本观点，并将对理解 与环境和宿主内腔中的霍乱弧菌生态学有关的基本生物学概念， 适用于多种细菌物种。

All living cells establish transmembrane electrochemical gradients with the help of primary ion pumps. Primary Na+ pumps have been discovered in many microorganisms of quite diverse phylogenic groups and a transmembrane circulation of Na+ ions may play a significant role in the physiology of several bacteria. The recent completion of many bacterial genome sequences revealed the presence of genes encoding a variety of sodium-dependent systems in many organisms, including some that were not known to have a primary sodium cycle of energy. This indicates that these bacteria can utilize Na+ as a coupling ion instead of, or in addition to, the H+ cycle. Although little is known about the role of the sodium cycle of energy in the physiology of Vibrio cholerae, the presence of a multitude of sodium-dependent systems encoded in the genome of this organism merits the investigation of its various Na+ pumps. In the present application we will construct and analyze defined mutants in Na+-extruding enzymes in V. cholerae as a model organism to gain further insights into this very complex and important part of bacterial physiology. We propose a comprehensive and systematic analysis of the components that contribute to bacterial sodium bioenergetics by using extensive genetic manipulations in combination with sophisticated bioenergetic measurements. Results of the proposed study will not only enhance our understanding of the general bioenergetic pathways in bacteria, but will form a solid basis for future investigations, by ourselves and others, of the molecular devices maintaining ion homeostasis in microorganisms. Sodium bioenergetics probably plays a role in both the environmental and pathogenic phases of the V. cholerae life cycle. Thus, our research has the potential for generating fundamental perspectives related to bacterial physiology and will be of value to understanding basic biological concepts related to V. cholerae ecology in the environment and in the lumen of hosts that will be applicable to a variety of bacterial species.