Berlin 2018 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 15: Postersession III

BP 15.85: Poster

Dienstag, 13. März 2018, 14:00–16:00, Poster B

Wobbling dynamics of E. coli cells in bulk and at walls — •Mahdiyeh Mousavi, Thomas Eisenstecken, Gerhard Gompper, and Roland G. Winkler — Institute of Complex Systems and Institute of Advanced Simulations, Forschungszentrum Juelich, Juelich, Germany

Wall entrapment of swimming bacteria like E. coli has been observed both experimentally and theoretically. However, the underlying mechanism of such a cell-wall interaction needs to be further addressed. In this study we identified three main stages of wall entrapment (approach, alignment, and surface swimming) by a mesoscale hydrodynamic simulation method, as was resolved experimentally. While the cell swims toward the surface, the time evolution of the cell angle with respect to the wall shows a fast oscillation (wobbling) around the alignment of the cell to the wall (pitch angle). In order to study the cell orientation, we consider different starting angles of the cell. We observe that the collision angle is linearly dependent on the start angle as is expected from the experiments. Moreover, once the cell reaches the wall, as it wobbles, it swims in a nose-down configuration with the bundle pointing away from the surface. The tangent of the pitch angle decreases exponentially with time after the collision, indicating that steric interactions play a major role in reorientation along with hydrodynamic interactions.