LExEn: Characterization of the Upper Pressure Limits for Microbial Life

巴特利特9714292太阳系中假设存在生命的许多区域，如欧罗巴海洋，其特征是压力远远大于地球表面所经历的压力。由于压力对生命的性质和分布产生了根本性的影响，因此需要了解高压对生命系统的影响。不幸的是，尽管从某些深海环境中分离出了喜欢高压的(常压)微生物，但关于常压环境的性质或生命可能存在的压力边界的数据相对较少。通过使用一组具有不同高压生长能力的细菌，并从能够以前所未有的速度生长的环境中分离和表征更多的耐压菌，正在研究高压下的生长机制和极限。压力。从两个基因可操纵的细菌，耐压大肠杆菌和中等耐压发光细菌菌株SS9，将在不同的培养条件下经过一系列逐步的高压选择制度获得突变体。与高压生长相关的基因将被识别和表征。此外，将有选择地在极端耐压希瓦尼拉菌种PT99中进化出更强的高压生长能力，并将使用从日本海沟内高压地点新鲜获得的沉积物来选择“超”耐压菌。通过16S rDNA测序，将确定分离出的具有最大高压生长能力的微生物的系统类型。

Bartlett 9714292 Many regions of the solar system where life is postulated to exist, such as the oceans of Europa, are characterized by pressures far greater than those experienced at Earth's surface. Because pressure exerts a fundamental influence on the properties and distribution of life, the effects of high pressure on living systems needs to be understood. Unfortunately, despite the isolation of high pressure-loving (barophilic) microbes from certain deep-sea environments, relatively little data exists on the nature of barophily or the pressure boundaries within which life may exist. The mechanisms and limits of growth at high pressure are being investigated by using a collection of bacteria of differing high pressure growth abilities, and by isolating and characterizing additional barophiles from the environment capable of growing at unprecedented. pressures. Mutants derived from two genetically manipulatable bacteria, barotolerant Escherichia coli, and moderately barophilic Photobacterium species strain SS9, will be obtained following a series of stepwise high pressure selection regimes under various culture conditions. Genes associated with high pressure growth will be identified and characterized. In addition, increased high pressure growth ability will be selectively evolved in the extreme barophile Shewanella species strain PT99, and "hyper" barophiles will be selected for, using sediments freshly obtained from a high pressure location within the Japan Trench. The phylotypes of those isolated microorganisms displaying greatest high pressure growth capability will be ascertained following 16S rDNA sequencing.