Dresden 2014 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 25: Statistical Physics in Biological Systems (joint DY/BP)
BP 25.6: Vortrag
Mittwoch, 2. April 2014, 11:00–11:15, ZEU 160
A time-continuous model for E. coli’s motion using shot noise — •Oliver Pohl1, Marius Hintsche2, Carsten Beta2, and Holger Stark1 — 1Institut für Theoretische Physik, Technische Universität Berlin, 10623 Berlin, Germany — 2Institut für Physik und Astronomie, Universität Potsdam, 14476 Potsdam, Germany
The bacterium Escherichia coli moves with alternating runs and tumbles that occur with a mean tumble rate. In the presence of gradients of a chemoattractant, E. coli performs chemotaxis [1]. It adjusts the tumble rate in response to the time-integrated concentration in order to increase the uptake of the chemical.
We set up a time-continuous model that describes runs and tumbles as a stochastic process of the bacterium’s swimming direction and speed. The swimming direction updates according to rotational Brownian motion and additional shot noise, which initiates tumbling events. The speed is not constant as in previous models but is determined by the random shots as well. By analyzing experimental data on swimming trajectories, we adjust the parameters of our model. First, we determine the shot noise from higher moments of the experimental trajectories. Second, we present a novel approach to determine the chemotactic response function, which E.Coli uses to integrate the chemical concentration in time. Finally, we want to use our model to explore the behavior of E. Coli in different chemical concentration profiles.
[1] H.C. Berg, “E.Coli in motion”, Springer, New York, (2003)