Alkaliphilic Bacteria with Impact on Industrial Applications, Concepts of Early Life Forms, and Bioenergetics of ATP Synthesis.
Alkaliphilic Bacteria with Impact on Industrial Applications, Concepts of Early Life Forms, and Bioenergetics of ATP Synthesis.
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DOI：
10.3389/fbioe.2015.00075
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发表时间：
2015
影响因子：
5.7
通讯作者：
Krulwich TA
中科院分区：
文献类型：
--
作者：
Preiss L;Hicks DB;Suzuki S;Meier T;Krulwich TA
嗜碱细菌通常在pH 9下生长良好，大多数极端嗜酸菌株生长至高达pH 12-13的pH值。在极端嗜碱菌的兴趣出现，因为他们是有用的，稳定的酶的来源，和细胞本身可以用于生物技术和其他应用在高pH值。此外，碱性热液喷口代表一个早期的进化生态位嗜碱菌和新的极端嗜碱菌最近也被发现在碱性serpentinizing网站。嗜碱菌的第三个关注点是非发酵嗜碱菌使用质子偶联ATP酶进行氧化磷酸化所带来的挑战。这就产生了一个问题，相对于化学渗透模型的原则，仍然是氧化磷酸化的生物能量学的核心模型。每一个嗜碱细菌的这些方面将讨论与极端嗜碱芽孢杆菌菌株的重点。这些嗜碱细菌提供了一个强有力的实验系统，以探测适应，使他们的生长和氧化磷酸化在高pH值。适应显然是需要的，使分泌或部分暴露的酶或蛋白质复合物在高外部pH值的功能。此外，嗜碱菌必须保持细胞质的pH值显着低于外部介质的pH值。这保护细胞质组分免受碱性足以损害其稳定性或功能的外部pH的影响。然而，跨细胞质膜的pH梯度，其内部比外部酸性更强的方向，与生物能量工作的生产方向相反。反向梯度降低了可用于激发ATP合成的跨膜质子动力。假设多种策略参与使嗜碱菌能够规避在高pH下激发质子偶联ATP合成的低体积质子动力的挑战。
Alkaliphilic bacteria typically grow well at pH 9, with the most extremophilic strains growing up to pH values as high as pH 12–13. Interest in extreme alkaliphiles arises because they are sources of useful, stable enzymes, and the cells themselves can be used for biotechnological and other applications at high pH. In addition, alkaline hydrothermal vents represent an early evolutionary niche for alkaliphiles and novel extreme alkaliphiles have also recently been found in alkaline serpentinizing sites. A third focus of interest in alkaliphiles is the challenge raised by the use of proton-coupled ATP synthases for oxidative phosphorylation by non-fermentative alkaliphiles. This creates a problem with respect to tenets of the chemiosmotic model that remains the core model for the bioenergetics of oxidative phosphorylation. Each of these facets of alkaliphilic bacteria will be discussed with a focus on extremely alkaliphilic Bacillus strains. These alkaliphilic bacteria have provided a cogent experimental system to probe adaptations that enable their growth and oxidative phosphorylation at high pH. Adaptations are clearly needed to enable secreted or partially exposed enzymes or protein complexes to function at the high external pH. Also, alkaliphiles must maintain a cytoplasmic pH that is significantly lower than the pH of the outside medium. This protects cytoplasmic components from an external pH that is alkaline enough to impair their stability or function. However, the pH gradient across the cytoplasmic membrane, with its orientation of more acidic inside than outside, is in the reverse of the productive orientation for bioenergetic work. The reversed gradient reduces the trans-membrane proton-motive force available to energize ATP synthesis. Multiple strategies are hypothesized to be involved in enabling alkaliphiles to circumvent the challenge of a low bulk proton-motive force energizing proton-coupled ATP synthesis at high pH.
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影响因子：
2.8
作者：
Fujinami, Shun;Fujisawa, Makoto
通讯作者：
Fujisawa, Makoto
影响因子：
4.4
作者：
Brazelton, William J.;Morrill, Penny L.;Schrenk, Matthew O.
通讯作者：
Schrenk, Matthew O.
影响因子：
3.4
作者：
Gessesse, A;Hatti-Kaul, R;Mattiasson, B
通讯作者：
Mattiasson, B
影响因子：
3.9
作者：
Frost, B. Ronald;Beard, James S.
通讯作者：
Beard, James S.
内膜的四十千克蛋白是线粒体钙Uniporter。
影响因子：
64.8
作者：
De Stefani, Diego;Raffaello, Anna;Teardo, Enrico;Szabo, Ildiko;Rizzuto, Rosario
通讯作者：
Rizzuto, Rosario