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SKM-DP: SKM Dissertation Prize 2011

SKM-DP 1: SKM Dissertation Prize

SKM-DP 1.1: Invited Talk

Tuesday, March 15, 2011, 10:30–11:00, TRE Ma

Chemotaxis of Sperm Cells: A generic principle for robust chemo-navigation along helical paths — •Benjamin M. Friedrich — Max Planck Institute for the Physics of Complex Systems, Dresden, Germany — Weizmann Institute of Science, Rehovot, Israel

Directed motion of biological cells in response to external cues requires coordination of cell sensation and cell motility. I discuss this interplay in the context of sperm chemotaxis and characterize a novel and universal navigation strategy. Sperm cells propel themselves in a liquid by regular bending waves of their whip-like flagellum. They can detect water-borne chemical cues released from the egg and steer their swimming paths upwards a concentration gradient. Detection of a gradient relies on temporal sampling of the concentration field along circular and helical swimming paths. I present a theoretical description of this navigation strategy and prove its robustness with respect to parameter variability and input noise. Robustness is crucial for reliable biological function and input noise might have been an evolutionary driving force in selecting cellular navigation strategies. The theory bridges the gap between experimentally well-characterized sperm chemotaxis in confined experimental geometries along circular paths and the biologically relevant case of unrestricted swimming along helical paths.