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BP: Fachverband Biologische Physik
BP 41: Microswimmers II (Joint Session with DY)
BP 41.4: Talk
Wednesday, March 9, 2016, 12:15–12:30, H45
Swimming dynamics of a polar multi-flagellated bacterium — •Marius Hintsche1, Matthias Theves1, Marco Kühn2, Kai Thormann2, and Carsten Beta1 — 1Universität Potsdam, Germany — 2Justus-Liebig-Universität Giessen, Germany
Bacterial motility patterns and chemotaxis strategies are very diverse and depend on factors such as flagellation as well as the typical environment the species encounters. For some bacteria the motility pattern and the underlying flagellar dynamics have already been elucidated – as in the paradigmatic run-and-tumble behavior of E. coli. We study the swimming motility and chemotactic behavior of the polar multi-flagellated soil dwelling bacterium Pseudomonas putida. Its run-and-reverse motility pattern with many sharp reversal events is reminiscent of the behavior of some monoflagellated species. However, upon a reversal, P. putida changes its swimming speed by a factor of two on average. We also analyze the swimming pattern in the presence of chemical gradients. Using benzoate as a chemoattractant, we measure key motility parameters in gradients of different strength in order to quantify the directional bias these conditions introduce in this swimmer’s random walk. Our results indicate a change in the reversal frequency depending on changes in the chemoattractant concentration consistent with earlier qualitative reports. Using high-speed fluorescence microscopy, we examine the dynamics of the polar bundle of flagella during smooth swimming and turning and discuss some recent hypotheses concerning the bundle dynamics of these bacteria in the light of our new observations.