Regensburg 2013 – scientific programme
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BP: Fachverband Biologische Physik
BP 24: Posters: Physics of Cells
BP 24.27: Poster
Wednesday, March 13, 2013, 17:30–19:30, Poster C
Fluctuations and differential contraction during regeneration of Hydra vulgaris tissue toroids — •Claus Fütterer1,2, Michael Krahe1, Iris Wenzel1, Kao-Nung Lin1, Julia Fischer1, Joseph Goldmann3, and Markus Kästner3 — 1Institut für Experimentelle Physik I, Universität Leipzig, 04103 Leipzig, Germany — 2Translationszentrum für Regenerative Medizin (TRM), Universität Leipzig — 3Institut für Festkörpermechanik, Technische Universität Dresden, 01062 Dresden, Germany
While much is known about the physics of single cells, the mechanics of self-organization and regeneration of cells in tissues and cell assemblies is largely unexplored. We studied regenerating tissue toroids from Hydra vulgaris and relate our macroscopic observations to the dynamics of force-generating mesoscopic cytoskeletal structures. Tissue fragments undergo a specific toroid-spheroid folding process leading to complete regeneration towards a new organism. The time scale of folding is too fast for biochemical signalling or morphogenetic gradients which forced us to assume purely mechanical self-organization. The initial pattern selection dynamics was studied by embedding toroids into hydro-gels allowing us to observe the deformation modes over longer periods of time. We found increasing mechanical fluctuations leading to an instability due to a supra-cellular actin ring destabilizing the toroidal symmetry. We discuss the evolution of their power spectra for various gel stiffnesses. Our observations are related to single cell studies which explain the mechanical feasibility of the folding process. In addition, we observed switching of cells from a tissue bound to a migrating state.