How Does Cilium Length Affect Beating?
How Does Cilium Length Affect Beating?
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DOI：
10.1016/j.bpj.2019.02.012
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发表时间：
2019-04-02
影响因子：
3.4
通讯作者：
Bayly, Philip, V
中科院分区：
文献类型：
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作者：
Bottier, Mathieu;Thomas, Kyle A.;Bayly, Philip, V
用高速摄像显微镜研究了纤毛长度对游动藻衣藻单纤毛突变体纤毛运动动力学的影响。通过pH冲击去纤毛细胞，并允许纤毛重组有限次，可获得纤毛较短的细胞。根据细胞体和纤毛的运动估计纤毛跳动的频率。纤毛波形的关键特征通过每帧图像中纤毛的多项式曲线进行量化。最值得注意的是，直到纤毛达到2到4毫米之间的临界长度时，才出现周期性跳动。令人惊讶的是，在周期性搏动的细胞中，所有长度的搏动频率都是相似的，只是随着长度从4 mm增加到正常的10-12微米，搏动频率略有下降，波形平均曲率(rad/mm)也随着纤毛的生长而保持不变。睫状肌推进的力学指标(力、力矩和功率)都随着长度的增加而成比例增加。纤毛行为的这些定量特征阐明了纤毛运动的生物物理学，在未来的研究中，可能有助于区分关于振荡潜在机制的相互竞争的假说。
The effects of cilium length on the dynamics of cilia motion were investigated by high-speed video microscopy of uniciliated mutants of the swimming alga, Chlamydomonas reinhardtii. Cells with short cilia were obtained by deciliating cells via pH shock and allowing cilia to reassemble for limited times. The frequency of cilia beating was estimated from the motion of the cell body and of the cilium. Key features of the ciliary waveform were quantified from polynomial curves fitted to the cilium in each image frame. Most notably, periodic beating did not emerge until the cilium reached a critical length between 2 and 4 mm. Surprisingly, in cells that exhibited periodic beating, the frequency of beating was similar for all lengths with only a slight decrease in frequency as length increased from 4 mm to the normal length of 10-12 mu m. The waveform average curvature (rad/mm) was also conserved as the cilium grew. The mechanical metrics of ciliary propulsion (force, torque, and power) all increased in proportion to length. The mechanical efficiency of beating appeared to be maximal at the normal wild-type length of 10-12 mu m. These quantitative features of ciliary behavior illuminate the biophysics of cilia motion and, in future studies, may help distinguish competing hypotheses of the underlying mechanism of oscillation.