The unique 16S rRNA genes of piezophiles reflect both phylogeny and adaptation
The unique 16S rRNA genes of piezophiles reflect both phylogeny and adaptation
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DOI：
10.1128/aem.01726-06
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发表时间：
2007-02-01
影响因子：
4.4
通讯作者：
Bartlett, Douglas H.
中科院分区：
文献类型：
--
作者：
Lauro, Federico M.;Chastain, Roger A.;Bartlett, Douglas H.
在海洋最极端的深处，70到110兆帕斯卡的压力会阻止所有生物的生长，但最喜欢压力的生物除外。在这些条件下生长所需的生理适应被认为是实质性的。到目前为止，确定允许在极端压力下生长的特定适应的努力主要集中在相对较少的伽马蛋白细菌上，部分原因是在纯培养中获得嗜压细菌存在技术困难。在这里，我们介绍了几个地理来源截然不同的新的嗜压菌的分子系统学。包括对从南半球(9.9公里深)发现的第一批深沟细菌分离株和第一批革兰氏阳性嗜压菌株的分析结果。这些新数据使得深海海沟嗜压菌和不适应高压的密切相关菌株之间进行了系统发育和结构上的16SRRNA比较。我们的结果表明：(I)环极深水作为高压菌的储存库，并推动它们传播到太平洋的深海沟；(Ii)16S rRNA基因中延长螺旋的出现随着对高压生长的适应程度的增加而增加。这些螺旋结构的变化被认为可以改善深海条件下的核糖体功能。
In the ocean's most extreme depths, pressures of 70 to 110 megapascals prevent the growth of all but the most hyperpiezophilic (pressure-loving) organisms. The physiological adaptations required for growth under these conditions are considered to be substantial. Efforts to determine specific adaptations permitting growth at extreme pressures have thus far focused on relatively few gamma-proteobacteria, in part due to the technical difficulties of obtaining piezophilic bacteria in pure culture. Here, we present the molecular phylogenies of several new piezophiles of widely differing geographic origins. Included are results from an analysis of the first deep-trench bacterial isolates recovered from the southern hemisphere (9.9-km depth) and of the first gram-positive piezophilic strains. These new data allowed both phylogenetic and structural 16S rRNA comparisons among deep-ocean trench piezophiles and closely related strains not adapted to high pressure. Our results suggest that (i) the Circumpolar Deep Water acts as repository for hyperpiezophiles and drives their dissemination to deep trenches in the Pacific Ocean and (ii) the occurrence of elongated helices in the 16S rRNA genes increases with the extent of adaptation to growth at elevated pressure. These helix changes are believed to improve ribosome function under deep-sea conditions.