Archaeal diversity along a subterranean salt core from the Salar Grande (Chile)
Archaeal diversity along a subterranean salt core from the Salar Grande (Chile)
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DOI：
10.1111/j.1462-2920.2011.02435.x
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发表时间：
2011-08-01
影响因子：
5.1
通讯作者：
McGenity, Terry J.
中科院分区：
文献类型：
--
作者：
Gramain, Audrey;Chong Diaz, Guillermo;McGenity, Terry J.
智利北方海岸山脉的大盐湖是一个化石碳酸盐盆地，充满了几乎纯的岩盐（平均95%NaCl）。据推测，该盆地自上新世（530万至180万年）以来没有接受过盐水输入。1米以下的岩盐自那时以来一直未溶解，而上层已被滴雾和偶尔的降雨溶解和重结晶。我们比较了古菌群落在不同深度使用巢式PCR和培养。上10厘米的岩盐地壳含有不同的盐古菌物种，包括几个新属，但其来源不明。对于更深处的样品，开发了一种新的严格的化学消毒岩盐单晶表面的程序。这些石盐晶体只含有盐杆菌属（Hbt.）的物种。通过PCR检测到盐生盐杆菌样序列，证明它们来自古代DNA的证据包括：与许多阴性对照进行比较;在非保守区域检测到16 S rRNA序列差异，表明真正的进化突变而不是PCR克隆产物; Hbt的独立分离。古岩盐中的salinarum;以及该物种具有的各种机制，以尽量减少辐射损害，从而提高其长期生存的潜力。盐古菌与Hbt有关。noricense从0.4和15.4 m深度的富集培养物中获得。我们调查了HBT。noricense菌株A1，并发现当被困在岩盐晶体中时，其在埋藏27个月后的恢复速度与第0天一样快，比其他极端嗜盐菌好得多。一项地理学调查表明，Hbt.类诺罗敦菌的生物体是：通常存在于与盐矿有关的表面灭菌的古岩盐中，存在于岩盐壳中，尽管进行了更密集的搜索，但在地表环境中很少发现。我们的结论是，一些盐杆菌物种是专家在长期生存的岩盐。
The Salar Grande in the Coastal Range of Northern Chile is a fossil evaporitic basin filled with almost pure halite (95% NaCl average). It is assumed that the basin has not received input of brines since the Pliocene (5.3 to 1.8 million years). Below 1 m the halite has remained undissolved since this time, whereas the upper layer has been dissolved and recrystallized by dripping fogs and occasional rainfall. We compared the archaeal community at different depths using both nested PCR and cultivation. The upper 10 cm of halite crust contained diverse haloarchaeal species, including several from new genera, but their provenance is unknown. For samples deeper in the core, a new and rigorous procedure for chemically sterilizing the surface of single halite crystals was developed. These halite crystals contained only species of the genus Halobacterium (Hbt.). Halobacterium salinarum-like sequences were detected by PCR, and evidence that they were from ancient DNA include: comparison with numerous negative controls; detection of 16S rRNA sequence differences in non-conserved regions, indicating genuine evolutionary mutations rather than PCR-cloning artefacts; independent isolation of Hbt. salinarum from ancient halite; and diverse mechanisms possessed by this species for minimizing radiation damage and thus enhancing its potential for long-term survival. Haloarchaea related to Hbt. noricense were obtained from enrichment cultures from similar to 0.4 and 15.4 m depth. We investigated Hbt. noricense strain A1 and found that when trapped inside halite crystals its recovery was as rapid after 27 months of entombment as at day 0, faring much better than other extreme halophiles. A biogeographical investigation showed that Hbt. noricense-like organisms were: commonly found in surface-sterilized ancient halite, associated with salt mines, in halite crusts, and, despite a much more intense search, only rarely detected in surface environments. We conclude that some Halobacterium species are specialists at long-term survival in halite.