Berlin 2024 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 11: Active Fluids and Microswimmers (joint session DY/BP/CPP)

CPP 11.7: Talk

Monday, March 18, 2024, 17:00–17:15, BH-N 243

Bacterial swimming strategies in a shear flow — •Valeriia Muraveva, Agniva Datta, and Carsten Beta — Potsdam University, Potsdam, Germany

By changing the configuration of their flagella, bacterial swimmers can control their direction and speed of locomotion. The soil bacterium Pseudomonas putida pushes itself forward by counterclockwise (CCW) rotation of its flagellar bundle, while clockwise (CW) rotation pulls the cell body in the opposite direction. Additionally, P. putida can wrap its bundle of flagella around the cell body to move in a screw thread fashion. However, the benefits of having different modes of swimming still remain unclear. Here, we used microfluidics in combination with fluorescence microscopy to show how the swimming behavior changes under laminar shear flow conditions. Compared to a fluid at rest, we found that in flow, swimmers prefer the pull configuration over the wrapped one (both emerging under CW flagellar rotation). Moreover, we investigated flow-induced alignment effects and compared the distributions of swimming modes and velocities in the bulk fluid and close to the fluid-substrate interface. Our results provide first insights into how bacteria adapt their swimming strategy under different flow conditions at the single-cell level.

Keywords: Bacteria swimmers; Shear stress; Microfluidic