Bacterial motion in narrow capillaries.
Bacterial motion in narrow capillaries.
复制标题
细菌在狭窄的毛细血管中运动。
DOI：
10.1093/femsec/fiu020
复制
发表时间：
2015
影响因子：
4.2
通讯作者：
Emberly,Eldon
中科院分区：
文献类型：
--
作者：
Ping,Liyan;Wasnik,Vaibhav;Emberly,Eldon
游动细菌通常必须穿过土壤或高等生物组织中的曲折小孔。然而，它们在这种盛行类型的利基中的运动还没有完全被理解。在这里，我们用狭窄的玻璃毛细血管对其进行建模，并确定了细菌运动的临界半径(RC)。在更窄的毛细血管表面附近，游动轨迹是螺旋状的。在较大的毛细血管中，它们以扭曲的圆圈游动。在非滑移条件下，富含细菌的大肠埃希菌在玻璃表面附近以左旋螺旋的形式游动，Rc为10μm。然而，当速度超过阈值时，快速单色荧光假单胞菌可能会发生滑动，因此左手螺旋和右手螺旋都在玻璃毛细管中执行。在天然的非圆柱形孔隙中，近地表的轨迹将是螺旋和扭曲的环状。进行这样的运动可以降低细菌的迁移率。对于给定的孔大小，细菌的游程长度和翻滚角度决定了它们在近表面运动的可能性和持续时间。剪切流和趋化性潜在地增强了它。基于这一观察，可以解释先前关于细菌在多孔环境中迁移的令人费解的观察结果。
Motile bacteria often have to pass through small tortuous pores in soil or tissue of higher organisms. However, their motion in this prevalent type of niche is not fully understood. Here, we modeled it with narrow glass capillaries and identified a critical radius (Rc) for bacterial motion. Near the surface of capillaries narrower than that, the swimming trajectories are helices. In larger capillaries, they swim in distorted circles. Under non-slip condition, the peritrichous Escherichia coli swam in left-handed helices with an Rc of ∼10 μm near glass surface. However, slipping could occur in the fast monotrichous Pseudomonas fluorescens, when a speed threshold was exceeded, and thus both left-handed and right-handed helices were executed in glass capillaries. In the natural non-cylindrical pores, the near-surface trajectories would be spirals and twisted loops. Engaging in such motions reduces the bacterial migration rate. With a given pore size, the run length and the tumbling angle of the bacterium determine the probability and duration of their near-surface motion. Shear flow and chemotaxis potentially enhance it. Based on this observation, the puzzling previous observations on bacterial migration in porous environments can be interpreted.