Nakamura Shuichi
Department of Applied Physics, Graduate School of Engineering, Tohoku University.
Nihon Saikingaku Zasshi. 2019;74(2):157-165. doi: 10.3412/jsb.74.157.
Bacteria, life living at microscale, can spread only by thermal fluctuation. However, the ability of directional movement, such as swimming by rotating flagella, gliding over surfaces via mobile cell-surface adhesins, and actin-dependent movement, could be useful for thriving through searching more favorable environments, and such motility is known to be related to pathogenicity. Among diverse migration mechanisms, perhaps flagella-dependent motility would be used by most species. The bacterial flagellum is a molecular nanomachine comprising a helical filament and a basal motor, which is fueled by an electrochemical gradient of cation across the cell membrane (ion motive force). Many species, such as Escherichia coli, possess flagella on the outside of the cell body, whereas flagella of spirochetes reside within the periplasmic space. Flagellar filaments or helical spirochete bodies rotate like a screw propeller, generating propulsive force. This review article describes the current knowledge of the structure and operation mechanism of the bacterial flagellum, and flagella-dependent motility in highly viscous environments.
细菌，作为微观尺度下的生命体，只能通过热涨落进行扩散。然而，其定向运动的能力，比如通过旋转鞭毛游动、借助可移动的细胞表面黏附素在表面滑行以及依赖肌动蛋白的运动，对于在寻找更适宜环境中蓬勃发展可能是有用的，并且这种运动性已知与致病性有关。在各种迁移机制中，或许大多数物种会采用依赖鞭毛的运动方式。细菌鞭毛是一种分子纳米机器，由螺旋状细丝和基部马达组成，其动力来自阳离子跨细胞膜的电化学梯度（离子动力）。许多物种，如大肠杆菌，在细胞体外部拥有鞭毛，而螺旋体的鞭毛则位于周质空间内。鞭毛细丝或螺旋状螺旋体身体像螺旋桨一样旋转，产生推进力。这篇综述文章描述了关于细菌鞭毛的结构和运行机制以及在高粘性环境中依赖鞭毛的运动性的当前知识。
