8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

Tue 611:23-14:00P10.39Mesoscale hydrodynamic simulation of bacterial flagellamotionShang Yik Reigh, 1 Roland G. Winkler, 1 and Gerhard Gompper 11 Institute of Complex Systems, Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Straße, 52425 Jülich, GermanyLocomotion of bacteria such as E. coli or Salmonella is achieved by rotations of bundles of helicalflagella. Transitions between straight swimming paths interrupted by short periods of tumblingplay an important role in the chemotaxis of the organisms. During swimming, all filamentsof a bundle rotate counter-clockwise and form a bundle. In tumbling, filaments are driven inreverse direction, transform into different conformations (polymorphism), and leave the bundle.A reversal of rotation again leads to the coherent motion of the bundle [1]. The bundle formationby several rotating helical filaments requires their synchronized rotation, which is governedby hydrodynamic interactions [2]. Therefore, in a simulation study of bacteria locomotion, atechnique is required, which adequately captures hydrodynamic interactions, on the one hand, andbridges the length- and time-scale gap between solvent and bacteria degrees of freedom on theother hand. The multiparticle collision (MPC) method [3, 4] satisfies these requirements. Resultsare presented for the synchronization and the bundle formation among three helical filaments.The filament is built as a sequence of mass points interacting by bond, bending, and torsionalpotentials. Such a model can efficiently be coupled to the MPC solvent. A linear relation isobtained between the angular velocity of the helix and an applied external torque for the singlefilament. The streamlines generated by the helical filament are determined. It is shown that synchronizationoccurs before bundle formation and that propulsion is more efficient for a tight bundle.[1] H. C. Berg, E. coli in Motion (Springer, New York, 2004)[2] H. C. Berg and R. A. Anderson, Nature 245, 382 (1973)[3] R. Kapral, Adv. Chem. Phys. 140, 89 (2008)[4] G. Gompper, T. Ihle, D. M. Kroll, and R. G. Winkler, Adv. Polym. Sci. 221, 1 (2009)39