Dresden 2026 – scientific programme
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BP: Fachverband Biologische Physik
BP 11: Franco-German Session: Bacterial Biophysics I
BP 11.8: Talk
Tuesday, March 10, 2026, 11:45–12:00, BAR/0106
Bacterial motility and chemotaxis in porous media: lophotrichously flagellated Pseudomonas putida exhibits run motility with mechanical trapping and active turning events that enable chemotaxis based on a turn-angle bias — •Sönke Beier1, Agniva Datta1, Veronika Pfeifer1, Robert Großmann1, and Carsten Beta1,2 — 1University of Potsdam, Institute of Physics, Germany — 2Kanazawa University, Nano Life Science Institute, Japan
Chemotaxis has been extensively studied in bulk liquid, particularly for the peritrichously flagellated Escherichia coli with its run-and-tumble motility, where navigation toward chemoattractants relies on a run-time bias, which extends runs when cells swim up nutrient gradients. Less is known about chemotaxis in environments, where confinement limits free swimming and reduces the effectiveness of a run-time bias. Previous studies suggest that E. coli also bias its turning angle, adjusting reorientations to favor subsequent runs toward the chemoattractant. By analyzing the soil bacterium P. putida in porous media, we identify run phases and active turning events -known from bulk liquid- and additional mechanical trappings caused by the environment[1]. We provide evidence that the bacterium performs chemotaxis by employing a turn-angle bias and show that the resulting directional preference of runs arises from the active, motor-induced turning events, while passive mechanical trapping in the porous matrix weakens the preference[2]. Agent-based simulations indicate that the turn-angle bias is the predominant chemotactic strategy[2]. [1] Datta et al.:Sci Rep 15, 20320 (2025), [2] Beier et al.:arXiv:2503.05286 (2025)
Keywords: Chemotaxis; Motility; Porous media; Confinement