Generic aspects of axonemal beating
Generic aspects of axonemal beating
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DOI：
10.1088/1367-2630/2/1/324
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发表时间：
2000-10-04
影响因子：
3.3
通讯作者：
Jülicher, F
中科院分区：
文献类型：
--
作者：
Camalet, S;Jülicher, F
我们研究了弹性棒状细丝在两个维度上的动力学，由内部产生的力驱动。这种情况是由含有轴丝的纤毛和鞭毛引起的。许多细胞的这些毛状附属物用于游泳和搅动周围的液体。我们的方法表征的一般物理机制，支配的行为轴丝和这些结构产生的弯曲波的属性。从动力学方程的细丝对在内力的存在下，我们使用微扰的方法来系统地计算细丝的形状和张力分布。我们发现，周期性的细丝运动可以产生的弹性细丝和内部的活性元素，如分子马达，通过一个动态的不稳定性称为霍普夫分岔的自组织。接近这种不稳定性，该系统的行为被证明是独立的许多微观细节的活性系统，只取决于唯象参数，如弯曲刚度，外部粘度和细丝长度。使用分子马达作为一个主动系统的两态模型，我们计算选定的振荡频率在分叉点，并表明，一个大的频率范围是通过改变轴丝长度1和50妈妈之间访问。讨论了边界条件和外力对轴丝波形的影响，并计算了自由边界条件下的游动速度。
We study the dynamics of an elastic rod-like filament in two dimensions, driven by internally generated forces. This situation is motivated by cilia and flagella which contain an axoneme. These hair-like appendages of many cells are used for swimming and to stir surrounding fluids. Our approach characterizes the general physical mechanisms that govern the behaviour of axonemes and the properties of the bending waves generated by these structures. Starting from the dynamic equations of a filament pair in the presence of internal forces we use a perturbative approach to systematically calculate filament shapes and the tension profile. We show that periodic filament motion can be generated by a self-organization of elastic filaments and internal active elements, such as molecular motors, via a dynamic instability termed Hopf bifurcation. Close to this instability, the behaviour of the system is shown to be independent of many microscopic details of the active system and only depends on phenomenological parameters such as the bending rigidity, the external viscosity and the filament length. Using a two-state model for molecular motors as an active system, we calculate the selected oscillation frequency at the bifurcation point and show that a large frequency range is accessible by varying the axonemal length between 1 and 50 mum. We discuss the effects of the boundary conditions and externally applied forces on the axonemal wave forms and calculate the swimming velocity for the case of free boundary conditions.