Dresden 2011 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 5: Statistical Physics of Biological Systems II (organised by DY)

DY 5.6: Talk

Monday, March 14, 2011, 15:30–15:45, HÜL 186

Modelling the African Trypanosome with stochastic rotation dynamics — •Sujin Babu and Holger Stark — Institut für Theoretische Physik Technische Universität Berlin

The dynamics of microorganisms in a viscous fluid has recently received considerable attention in the physics community. It has been reported that the African Trypanosome makes use of hydrodynamic flow fields to evade attack from antibodies in the blood stream. The spindle-shaped flexible cell body of the African Trypanosome possesses some bending rigidity due to its cytoskeleton. A single flagellum runs from the thicker posterior end to the thinner anterior end of the cell body and is firmly attached to it. By propagating a wave along the flagellum from the anterior to the posterior end, the trypanosome moves forward. However, the details of this propulsion mechanism is still under debate. Our goal is to study a model trypanosome in its viscous environment. We model the cell body and the flagellum as a net of vertices connected by springs and also include some resistance to bending. A bending wave passing through the flagellum propels the trypanosome. We simulate the flow field around the model trypanosome using the method of stochastic rotation dynamics, which is an effective solver for the Navier-Stokes equations but also includes thermal fluctuations. We will demonstrate how the model trypanosome is coupled to the effective fluid particles of stochastic rotation dynamics. We will also discuss the propulsion mechanism of the microorganism and demonstrate that our modeling reproduces different shape conformations observed in experiments.