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DY: Fachverband Dynamik und Statistische Physik
DY 9: Statistical Physics of Biological Systems II (with BP, talks from BP)
DY 9.4: Vortrag
Montag, 26. März 2012, 15:45–16:00, H 1058
Geometrical trajectories of a Listeria-type actin-driven particle in 2D — •Fu-Lai Wen1, Kwan-tai Leung1,3, and Hsuan-Yi Chen1,2,3 — 1National Central University, Jhongli, Taiwan 32001, Republic of China — 2Physics Division, National Center for Theoretical Sciences, Hsinchu, Taiwan 30113, Republic of China — 3Institute of Physics, Academia Sinica, Taipei, Taiwan 11529, Republic of China
Self-propulsions have been a focus of the non-equilibrium statistical physics where an input energy is converted into the kinetic energy of motion. It is interesting that a deformable self-propelled domain is shown to generate a series of geometrical trajectories like circles, wiggles, etc. A similar result is also found in the motion of a bacterium Listeria which, although not deformable, moves in a geometrical trajectory by the polymerization of protein actin on its surface. Similar actin-driven motility was also shown in vitro studies on functionalized beads or disks. Here, a phenomenological model is constructed for the generation of geometrical trajectories of a Listeria-type actin-driven spherical particle in two dimensions. In our model, the evolutions of actin filament density and force on surface are coupled to the translation and rotation of the particle which in turn are determined by those densities. It is shown that this feedback can destabilize the straight trajectories and lead to the geometrical trajectories observed in experiments. It further shows that a straight trajectory transits to a circular one through a pitchfork bifurcation or to a wiggled one through a Hopf bifurcation on the distributions of those densities. This transition mechanism is generic and robust as indicated in our studies.