Berlin 2015 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 54: Microswimmers, Active Liquids III (joint DY/BP/CPP)

BP 54.4: Vortrag

Freitag, 20. März 2015, 10:30–10:45, C 264

Tangled Flagella: Importance in Bacterial Propulsion — •Tapan Chandra Adhyapak and Holger Stark — Institut für Theoretische Physik, Technische Universität Berlin, D - 10623 Berlin

It has been well established that hydrodynamic interactions between flagella of peritrichous bacteria such as E. coli, leads to synchronization of rotation and bundling of those flagella [1,2]. Flagella are rotated at their bases by rotary motors embedded in the cell body. In response, the cell body has to rotate in the opposite sense such that total torque acting on the bacterium is zero. Often, such cell rotation causes flagella to tangle before they are synchronized completely. We show that tangling has a profound effect on the overall synchronization and bundling dynamics. In particular, we observe abrupt synchronization and bundling on time scales much shorter than those required when the cell movement is switched off to avoid entanglement. Although hydrodynamic interactions still play an important role, through a comparative investigation we conclude that flagellar entanglement generated by cell rotation predominantly affects the total time to synchronize and bundle. Cell movement modifies stationary bundling states too. Specifically, the length over which a bundle is closely pact varies over time, having an oscillatory behavior whose amplitude decreases with increasing number of flagella. At the end we discuss how strongly all these findings affect the overall propulsion of the bacterium.

[1] M. Reichert and H. Stark, Eur. Phys. J. E 17, 493 (2005).
S.Y. Reigh, R.G. Winkler, and G. Gompper, Soft Matter 8, 4363 (2012).