Helical trajectories of swimming cells with a flexible flagellar hook
Helical trajectories of swimming cells with a flexible flagellar hook
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DOI：
10.1103/physrevfluids.6.103102
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发表时间：
2021-06
影响因子：
2.7
通讯作者：
Zonghao Zou;W. Lough;S. Spagnolie
中科院分区：
文献类型：
--
作者：
Zonghao Zou;W. Lough;S. Spagnolie
细菌鞭毛钩的灵活性被认为对微生物的运动有实质性的影响。利用刚性鞭毛和柔性钩的简化模型，我们证明了由单个鞭毛驱动的轴对称细胞体在Stokes流中的路径一般是螺旋的。产生了相平均阻力和迁移率张量来描述鞭毛流体动力学，并且将保留平移和旋转之间耦合的螺旋杆模型确定为区分的渐近极限。鞭毛方向的超临界霍普夫分叉超过鞭毛电机扭矩与钩弯曲刚度的临界比率（由柔性钩的自发曲率、细胞体形状和鞭毛几何形状决定），会对细胞在流体中的运动轨迹产生巨大影响。虽然平衡钩角会导致轨迹的螺旋螺距变化很大，但我们发现使用与游泳铜绿假单胞菌细胞相关的参数对轨迹的螺旋振幅进行了非常一致的预测。
The flexibility of the bacterial flagellar hook is believed to have substantial consequences for microorganism locomotion. Using a simplified model of a rigid flagellum and a flexible hook, we show that the paths of axisymmetric cell bodies driven by a single flagellum in Stokes flow are generically helical. Phase-averaged resistance and mobility tensors are produced to describe the flagellar hydrodynamics, and a helical rod model which retains a coupling between translation and rotation is identified as a distinguished asymptotic limit. A supercritical Hopf bifurcation in the flagellar orientation beyond a critical ratio of flagellar motor torque to hook bending stiffness, which is set by the spontaneous curvature of the flexible hook, the shape of the cell body, and the flagellum geometry, can have a dramatic effect on the cell's trajectory through the fluid. Although the equilibrium hook angle can result in a wide variance in the trajectory's helical pitch, we find a very consistent prediction for the trajectory's helical amplitude using parameters relevant to swimming P. aeruginosa cells.