Berlin 2018 – scientific programme
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BP: Fachverband Biologische Physik
BP 18: Focus Session: Physics of Microbial Systems - organized by Tobias Bollenbach and Benedikt Sabass
BP 18.12: Talk
Wednesday, March 14, 2018, 12:45–13:00, H 2013
Mechanics of twitching migration of the bacterium P. aeruginosa — •Ahmet Nihat Simsek1, Matthias D. Koch2, Benedikt Sabass1, Gerhard Gompper1, Zemer Gitai2, and Joshua W. Shaevitz2 — 1Theoretical Soft Matter and Biophysics, Institute of Complex Systems and Institute of Advanced Simulation, Forschungszentrum Juelich, D-52425 Juelich, Germany — 2Lewis-Sigler Institute for Integrative Genomics, Princeton University, NJ 08544
Pseudomonas aeruginosa is an ubiquitous pathogen responsible for severe and chronic infections. The bacterium employs retractable type-IV pili for migration and colonizes a broad variety of biotic and abiotic surfaces. How surface properties affect migration and colony formation of P. aeruginosa is a potentially important factor for bacterial surface contamination and infections alike. Here, we theoretically and experimentally study the effect of surface properties on the migration of P. aeruginosa. In our model, we assume a rod-like bacterium and treat each pilus, as well as the substrate as elastic springs. Pilus assembly and retraction are modeled as stochastic, force-dependent processes. To generate experimental data, we perform extensive image analysis to record the migration of different strains of P. aeruginosa on polyacrylamide substrates. Experimental data shows a non-linear dependence of migration speed and mean square displacement on substrate properties, which is in accordance with simulations. Finally, we present an analytical theory including the calculation of effective diffusion coefficients and aggregation probabilities of bacteria.