Regensburg 2010 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

BP: Fachverband Biologische Physik

BP 32: Posters: Physics of Cells

BP 32.34: Poster

Donnerstag, 25. März 2010, 17:15–20:00, Poster B1

Chemotaxis model for bacteria with twitching motility — •Johannes Taktikos, Vasily Zaburdaev, and Holger Stark — Institut für Theoretische Physik, Technische Universität Berlin, Hardenbergstr. 36, D-10623 Berlin, Germany

We construct a model to study the characteristic motion of bacteria on a surface. Once bacteria, such as Pseudomonas aeruginosa or Neisseria gonorrhoeae, reach a surface they lose their helical flagella and instead use filaments, so-called type IV pili, to move forward. The resulting twitching motility represents an important and necessary mechanism that many types of bacteria use to form biofilms.

The main ingredient in our model is chemotaxis. This describes the bacterium’s ability to orient its velocity direction along the gradient of the chemotactic field which is given by the concentration of a certain chemical. In our case, the chemical is produced by the bacteria themselves to attract each other and obeys a simple reaction diffusion equation. In a first approach, we neglect fluctuations in the absolute value of a bacterium’s velocity and formulate a Langevin equation for the direction of the velocity. It consists of a deterministic part due to chemotaxis and a stochastic term representing both thermal and other sources of noise. The stochastic term alone would lead to rotational diffusion. Using computer simulations, we analyze possible time-dependent structures of bacterial paths and classify different patterns of collective motion.