Propulsive Forces on the Flagellum during Locomotion of Chlamydomonas reinhardtii
Propulsive Forces on the Flagellum during Locomotion of Chlamydomonas reinhardtii
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DOI：
10.1016/j.bpj.2011.05.001
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发表时间：
2011-06-08
影响因子：
3.4
通讯作者：
Dutcher, S. K.
中科院分区：
文献类型：
--
作者：
Bayly, P. V.;Lewis, B. L.;Dutcher, S. K.
根据实验图像数据估算了周围流体对游动藻衣藻鞭毛的分布推进力。在350帧/S、125 nm空间分辨率下获得了单鞭毛突变衣藻细胞的图像，并在低雷诺数流体力学的背景下分析了细胞体和鞭毛的运动。研究了野生型单鞭毛细胞以及缺少内动力蛋白臂(Ida3)或外动力蛋白臂(Oda2)的单鞭毛细胞。IDA3细胞表现出发育迟缓的鞭毛波形，而ODA2细胞则以较低的频率跳动。图像配准和分类算法提供了对细胞体运动的高分辨率估计，以及鞭毛的详细运动学。在Stokes流中，游动细胞被模拟为一个椭球体，由鞭毛上的粘性力推动。鞭毛上的法向和切向力分量(f(N)和f(T))由阻力系数(C(N)和C(T))与相应的速度分量(V(N)和V(T))相关。通过满足电池上的力和扭矩的平衡要求来估计这些系数的值。抗性系数的估计值在所有三种基因型中都是一致的，与理论预测相似。
The distributed propulsive forces exerted on the flagellum of the swimming alga Chlamydomonas reinhardtii by surrounding fluid were estimated from experimental image data. Images of uniflagellate mutant Chlamydomonas cells were obtained at 350 frames/s with 125-nm spatial resolution, and the motion of the cell body and the flagellum were analyzed in the context of low-Reynolds-number fluid mechanics. Wild-type uniflagellate cells, as well as uniflagellate cells lacking inner dynein arms (ida3) or outer dynein arms (oda2) were studied. Ida3 cells exhibit stunted flagellar waveforms, whereas oda2 cells beat with lower frequency. Image registration and sorting algorithms provided high-resolution estimates of the motion of the cell body, as well as detailed kinematics of the flagellum. The swimming cell was modeled as an ellipsoid in Stokes flow, propelled by viscous forces on the flagellum. The normal and tangential components of force on the flagellum (f(N) and f(T)) were related by resistive coefficients (C(N) and C(T)) to the corresponding components of velocity (V(N) and V(T)). The values of these coefficients were estimated by satisfying equilibrium requirements for force and torque on the cell. The estimated values of the resistive coefficients are consistent among all three genotypes and similar to theoretical predictions.