Testing an agent-based model of bacterial cell motility: How nutrient concentration affects speed distribution

Authored by M. Birbaumer, Frank Schweitzer, V. Garcia

Date Published: 2011-08

DOI: 10.1140/epjb/e2011-20425-2

Sponsors: No sponsors listed

Platforms: No platforms listed

Model Documentation: Other Narrative Mathematical description

Model Code URLs: Model code not found

Abstract

We revisit a recently proposed agent-based model of active biological motion and compare its predictions with own experimental findings for the speed distribution of bacterial cells, Salmonella typhimurium. Agents move according to a stochastic dynamics and use energy stored in an internal depot for metabolism and active motion. We discuss different assumptions of how the conversion from internal to kinetic energy d(v) may depend on the actual speed, to conclude that d(2)v(xi) with either xi = 2 or 1 < xi < 2 are promising hypotheses. To test these, we compare the model's prediction with the speed distribution of bacteria which were obtained in media of different nutrient concentration and at different times. We find that both hypotheses are in line with the experimental observations, with xi between 1.67 and 2.0. Regarding the influence of a higher nutrient concentration, we conclude that the take-up of energy by bacterial cells is indeed increased. But this energy is not used to increase the speed, with 40 mu m/s as the most probable value of the speed distribution, but is rather spend on metabolism and growth.

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