Dresden 2017 – scientific programme

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BP: Fachverband Biologische Physik

BP 27: Posters - Microswimmers

BP 27.1: Poster

Tuesday, March 21, 2017, 14:00–16:00, P2-EG

A bacterial swimmer with two alternative movement patterns — Veronika Waljor, Marius Hintsche, •Zahra Alirezaeizanjani, and Carsten Beta — Institute of Physics and Astronomy, University of Potsdam, Potsdam-Golm, Germany

The soil bacterium Pseudomonas putida is a bacterial swimmer that propels itself with the help of several flagella that are polarly arranged at one end of the cell body. Through its chemosensory system, which is coupled to the rotary motors that drive the flagella, P. putida senses changes in its environment and responds by altering its motility.

When growing in a medium that offers only minimal amounts of nutrient, P. putida exhibits a motion pattern characterized by persistent runs that are interrupted by reversals in the swimming direction. In contrast, when growing under rich medium conditions, the reversal rate is drastically reduced and the swimming pattern is dominated by stopping events that interrupt the episodes of persistent runs.

Additional experiments in microfluidic gradient chambers suggest that the reversals are signatures of a chemotactic strategy, which is activated when food is sparse but not required under rich growth conditions.