Berlin 2012 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 17: Posters: Physics of Cells
BP 17.18: Poster
Mittwoch, 28. März 2012, 17:30–19:30, Poster A
Stochastic modeling of malaria parasite motility — •Thorsten Erdmann1, Yin Cai2, and Ulrich S. Schwarz1,2 — 1Institute of Theoretical Physics, Heidelberg University, Heidelberg, Germany — 2BioQuant, Heidelberg University, Heidelberg, Germany
During its lifecycle, the unicellular malaria parasite from the Plasmodium family alternates between insect and vertebrate hosts. A critical step of its lifecycle is the entry of Plasmodium sporozoites into blood vessels after injection into the skin of a vertebrate host during a mosquito bite. In vitro experiments on two-dimensional substrates with microfabricated arrays of obstacles reveal complex motion patterns resembling the ones observed in vivo in the skin, with long stretches of circular or linear motion separated by abrupt changes of direction. We model the sporozoite motion using a stochastic glider model, in which the rod-like glider describes a circular path when unperturbed, but changes direction randomly upon collisions with an obstacle. This model leads to patterns of motion similar to those observed in experiment and describes well the average displacement as function of time. On the sub-second time-scale, sporozoites seem to move in a stick-slip-like fashion. In order to assess short time-scales, we introduce a model for the propulsion mechanism of sporozoites, in which the sporozoite body attaches to a substrate via specialized binding molecules, which are then displaced by small groups of non-processive motors.