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DY: Dynamik und Statistische Physik

DY 16: Statistical physics in biological systems II

DY 16.1: Hauptvortrag

Montag, 24. März 2003, 16:15–16:45, G\"OR/226

Modeling pattern formation in biological systems — •Markus Bär — MPI für Physik komplexer Systeme, Nöthnitzer Str. 38, 01187 Dresden

Biophysical and biological experiments show that pattern formation occurs in single cells as well as in multicellular aggregates and tissues. In this talk, we discuss modeling approaches and highlight two recent examples. First, a model for domains of acidic lipids in biomembranes is described. It includes interaction with the protein MARCKS as well as biochemical parameters that control the membrane binding and unbinding of the protein. The coupling of transport with biochemistry yields sustained domains and waves in the micrometer range (1). Second, standing-wave-type ripple patterns caused by developmental signals in aggregates of myxobacteria are reproduced in a cell-based model. Patterns arise from the interplay of active migration of bacteria and exchange of chemical signals upon cell-cell contact. Head-on collisions of cells cause reversal of the direction of motion. A correct description of the rippling patterns requires a mimimum time interval between subsequent reversals (refractory period). Altogether, rippling provides an example for a new mechanism of pattern formation based upon migration and time delay instead of the more common reaction-diffusion process (2). References: (1) K. John and M. Bär, in preparation (2003). (2) U. Börner et al., Phys. Rev. Lett. 89, 078101 (2002).