LExEn: Characterization of the Upper Pressure Limits for Microbial Life

Bartlett 9714292太阳系中许多被认为存在生命的区域，例如木卫二的海洋，其特征是压力远远大于地球表面的压力。由于压力对生命的性质和分布产生根本性的影响，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嗜高压（嗜压）微生物，但关于嗜压性的性质或生命可能存在的压力边界的数据相对较少。 在高压下生长的机制和限制正在研究通过使用不同的高压生长能力的细菌的集合，并通过分离和表征额外的嗜压菌从环境中能够在前所未有的增长。压力 在各种培养条件下进行一系列逐步高压选择方案后，将获得来自两种可遗传操作的细菌（耐压大肠杆菌和中度嗜压发光杆菌属菌株SS9）的突变体。将鉴定和表征与高压生长相关的基因。 此外，增加的高压生长能力将选择性地在极端嗜压希瓦氏菌物种菌株PT99中进化，并将选择“超”嗜压菌，使用从日本海沟内的高压位置新鲜获得的沉积物。这些分离的微生物显示最大的高压生长能力的菌株类型将通过16S rDNA测序确定。

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.