Ramaswamy Rajesh, Jülicher Frank
Max Planck Institute for the Physics of Complex Systems (MPI-PKS), Nöthnitzer Str. 38, 01187 Dresden, Germany.
Sci Rep. 2016 Feb 15;6:20838. doi: 10.1038/srep20838.
Inspired by the actomyosin cortex in biological cells, we investigate the spatiotemporal dynamics of a model describing a contractile active polar fluid sandwiched between two external media. The external media impose frictional forces at the interface with the active fluid. The fluid is driven by a spatially-homogeneous activity measuring the strength of the active stress that is generated by processes consuming a chemical fuel. We observe that as the activity is increased over two orders of magnitude the active polar fluid first shows spontaneous flow transition followed by transition to oscillatory dynamics with traveling waves and traveling vortices in the flow field. In the flow-tumbling regime, the active polar fluid also shows transition to spatiotemporal chaos at sufficiently large activities. These results demonstrate that level of activity alone can be used to tune the operating point of actomyosin layers with qualitatively different spatiotemporal dynamics.
受生物细胞中肌动球蛋白皮层的启发，我们研究了一个模型的时空动力学，该模型描述了夹在两种外部介质之间的收缩性活性极性流体。外部介质在与活性流体的界面处施加摩擦力。流体由空间均匀的活性驱动，该活性测量由消耗化学燃料的过程产生的活性应力的强度。我们观察到，随着活性增加两个数量级以上，活性极性流体首先表现出自发流动转变，随后转变为振荡动力学，流场中出现行波和行涡。在流动翻滚 regime 中，活性极性流体在足够大的活性下也表现出向时空混沌的转变。这些结果表明，仅活性水平就可用于调整具有定性不同时空动力学的肌动球蛋白层的工作点。
