Regensburg 2019 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 64: Active Matter III (joint session BP/CPP/DY)

CPP 64.6: Talk

Friday, April 5, 2019, 10:45–11:00, H11

Effects of collective bacterial motility on their chemotactic navigation — •Remy Colin and Victor Sourjik — Max Planck Institute for Terrestrial Microbiology, Marburg, Germany

At high cell density, swimming bacteria exhibit collective motility patterns, self-organized through physical interactions of a however still debated nature. Although high-density behaviors are frequent in natural situations, it remains unknown how collective motion affects chemotaxis, the main physiological function of motility that enables bacteria to follow chemical and other gradients in their environment. Here, we systematically investigated this question in the model organism Escherichia coli, varying cell density, cell length and suspension confinement. The characteristics of the collective motion indicated that its emergence is dominated by hydrodynamic interactions between swimmers. We observed that moderate increase in cell density enhanced the chemotactic drift of bacteria, whereas it was suppressed at higher densities, because the collective motion disturbed the choreography necessary for chemotactic sensing. We suggest that this physical hindrance imposes a fundamental constraint on high-density behaviors of motile bacteria, including swarming as well as the formation of multicellular aggregates and biofilms.