Dresden 2009 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 1: Dynamic Processes and Pattern Formation
BP 1.6: Vortrag
Montag, 23. März 2009, 12:00–12:15, HÜL 186
Mechanically driven reaction-diffusion model for Hydra axis-definition — Jordi Soriano1, •Sten Rüdiger2, and Albrecht Ott3 — 1Universitat de Barcelona, Spain — 2Humboldt-Universität zu Berlin, Germany — 3Universität des Saarlandes, Saarbrücken, Germany
We have studied the relation between morphogenetic processes and mechanical properties during regeneration of the freshwater polyp Hydra. It has been known that the axis-defining step (symmetry-breaking) of regeneration requires mechanical inflation-collapse oscillations of the initial cell ball. We found evidence that axis definition is retarded if these oscillations are slowed down mechanically. We show that a reaction-diffusion mechanism provides a suitable scenario to describe the Hydra symmetry breaking. We employ a model in which the swelling of the initial Hydra cell ball induces changes in the diffusivity rates of activator and inhibitor. The mechanical stress provided by the oscillations drives the system to the Turing unstable regime. Once the organizer is constituted and a chemical gradient is established, the organizer locks and maintains the axis. Analytical considerations of the model show that the symmetry breaking time decreases with increasing swelling rate with the same behavior observed experimentally.