Wakai Satoshi
a Graduate School of Science, Technology and Innovation , Kobe University , Kobe , Japan.
Biosci Biotechnol Biochem. 2019 Jan;83(1):49-64. doi: 10.1080/09168451.2018.1538769. Epub 2018 Oct 31.
A variety of extreme environments, characterized by extreme values of various physicochemical parameters (temperature, pressure, salinity, pH, and so on), are found on Earth. Organisms that favorably live in such extreme environments are called extremophiles. All living organisms, including extremophiles, must acquire energy to maintain cellular homeostasis, including extremophiles. For energy conversion in harsh environments, thermodynamically useful reactions and stable biomolecules are essential. In this review, I briefly summarize recent studies of extreme environments and extremophiles living in these environments and describe energy conversion processes in various extremophiles based on my previous research. Furthermore, I discuss the correlation between the biological system of electrotrophy, a third biological energy acquisition system, and the mechanism underlying microbiologically influenced corrosion. These insights into energy conversion in extremophiles may improve our understanding of the "limits of life". Abbreviations: PPi: pyrophosphate; PPase: pyrophosphatase; ITC: isothermal titration microcalorimetry; SVNTase: Shewanella violacea 5'-nucleotidase; SANTase: Shewanella amazonensis 5'-nucleotidase.
地球上存在着各种极端环境，其特点是各种物理化学参数（温度、压力、盐度、pH值等）处于极端值。能够在这种极端环境中良好生存的生物被称为嗜极生物。所有生物，包括嗜极生物，都必须获取能量以维持细胞内稳态。对于在恶劣环境中的能量转换而言，热力学上有用的反应和稳定的生物分子至关重要。在这篇综述中，我简要总结了近期关于极端环境以及生活在这些环境中的嗜极生物的研究，并基于我之前的研究描述了各种嗜极生物中的能量转换过程。此外，我还讨论了第三种生物能量获取系统——电营养生物系统与微生物影响腐蚀的潜在机制之间的关联。这些对嗜极生物能量转换的见解可能会增进我们对“生命极限”的理解。缩写：PPi：焦磷酸；PPase：焦磷酸酶；ITC：等温滴定量热法；SVNTase：紫色希瓦氏菌5'-核苷酸酶；SANTase：亚马逊希瓦氏菌5'-核苷酸酶。
