Berlin 2015 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 34: Statistical Physics of Biological Systems II (joint BP/DY/CPP)
BP 34.2: Vortrag
Mittwoch, 18. März 2015, 09:45–10:00, H 1028
Statistical Inference of E.Coli’s tumbling behavior and chemotaxis strategy using Kramers-Moyal coefficients — •Oliver Pohl1, Marius Hintsche2, Carsten Beta2, and Holger Stark1 — 1Institut für Theoretische Physik, Technische Universität Berlin, 10623 Berlin — 2Institut für Physik und Astronomie, Universität Potsdam, 14476 Potsdam
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. 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 decreases during the tumbling events.
By analyzing experimental data on swimming trajectories, we infer the parameters of our model. To this purpose generalized Kramers-Moyal coefficients are calculated for our shot-noise model and matched to the ones obtained from the trajectories. In contrast to common tumbling recognition algorithms no free parameters need to be predetermined. Furthermore, we can identify the bacteria’s chemotaxis strategy by exploiting the Kramers-Moyal coefficients.