The halophilic alkalithermophile Natranaerobius thermophilus adapts to multiple environmental extremes using a large repertoire of Na(K)/H antiporters.
The halophilic alkalithermophile Natranaerobius thermophilus adapts to multiple environmental extremes using a large repertoire of Na(K)/H antiporters.
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DOI：
10.1111/j.1365-2958.2009.06845.x
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发表时间：
2009-10
影响因子：
3.6
通讯作者：
Wiegel J
中科院分区：
文献类型：
--
作者：
Mesbah NM;Cook GM;Wiegel J
嗜热嗜钠菌是一种不寻常的极端微生物，因为它是嗜盐，嗜碱和嗜热的，最佳生长条件为3.5 M Na+，pH 55 °C 9.5和53°C。这种三方生活方式的机制对于了解微生物如何在恶劣条件下生长至关重要，但仍然未知，特别是在极端条件下生长的极端微生物。我们报道了N.嗜热菌在高盐和高温下对外部pH的适应，并确定负责这种适应的机制。N.嗜热菌表现出细胞质酸化，在整个细胞外pH范围内维持1个单位的意外跨膜pH梯度用于生长。N.嗜热菌使用两种不同的细胞质酸化机制。在最适pH值和低于最适pH值时，N.嗜热菌利用至少八种产电Na+（K+）/H+反向转运蛋白进行细胞质酸化。在反向转运蛋白缺陷的大肠杆菌KNabc中，这些反向转运蛋白的特征显示出重叠的pH曲线（pH 7.8-10.0）和活性的Na+浓度（K0.5值1.0-4.4 mM），这些特性与N.嗜热菌随着细胞外pH值增加超过最佳值，产电反向转运活性停止，并且细胞质酸化通过可能由酸性蛋白质组介导的能量独立的生理化学效应（细胞质缓冲）来实现。这些策略的组合允许N.嗜热菌可以在细胞外pH和Na+浓度范围内生长，并在多种极端条件下保护生物分子。
Natranaerobius thermophilus is an unusual extremophile because it is halophilic, alkaliphilic and thermophilic, growing optimally at 3.5 M Na+, pH55°C 9.5 and 53°C. Mechanisms enabling this tripartite lifestyle are essential for understanding how microorganisms grow under inhospitable conditions, but remain unknown, particularly in extremophiles growing under multiple extremes. We report on the response of N. thermophilus to external pH at high salt and elevated temperature and identify mechanisms responsible for this adaptation. N. thermophilus exhibited cytoplasm acidification, maintaining an unanticipated transmembrane pH gradient of 1 unit over the entire extracellular pH range for growth. N. thermophilus uses two distinct mechanisms for cytoplasm acidification. At extracellular pH values at and below the optimum, N. thermophilus utilizes at least eight electrogenic Na+(K+)/H+ antiporters for cytoplasm acidification. Characterization of these antiporters in antiporter-deficient Escherichia coli KNabc showed overlapping pH profiles (pH 7.8–10.0) and Na+ concentrations for activity (K0.5 values 1.0–4.4 mM), properties that correlate with intracellular conditions of N. thermophilus. As the extracellular pH increases beyond the optimum, electrogenic antiport activity ceases, and cytoplasm acidification is achieved by energy-independent physiochemical effects (cytoplasmic buffering) potentially mediated by an acidic proteome. The combination of these strategies allows N. thermophilus to grow over a range of extracellular pH and Na+ concentrations and protect biomolecules under multiple extreme conditions.
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影响因子：
14.9
作者：
Ren Q;Chen K;Paulsen IT
通讯作者：
Paulsen IT
DOI：
10.1196/annals.1419.006
发表时间：
2008-01-01
期刊：
INCREDIBLE ANAEROBES: FROM PHYSIOLOGY TO GENOMICS TO FUELS
影响因子：
--
作者：
Fisher, Edward;Dawson, Asia M.;Stolz, John F.
通讯作者：
Stolz, John F.
DOI：
10.1007/0-387-30743-5_3
发表时间：
2006-01-01
期刊：
PROKARYOTES: A HANDBOOK ON THE BIOLOGY OF BACTERIA, VOL 3, THIRD EDITION
影响因子：
--
作者：
Huber, Harald;Prangishvili, David
通讯作者：
Prangishvili, David
影响因子：
4.3
作者：
Krulwich, TA;Ito, M;Hicks, DB
通讯作者：
Hicks, DB
影响因子：
3.6
作者：
Radchenko, MV;Waditee, R;Nakamura, T
通讯作者：
Nakamura, T