Dresden 2020 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 16: Poster IV
BP 16.8: Poster
Dienstag, 17. März 2020, 14:00–16:00, P2/EG
Chiral symmetry breaking in viscous environments — •Jonas Neipel1, Stephan W. Grill2,3, and Frank Jülicher1 — 1Max-Planck-Institute for the Physics of Complex Systems, Dresden, Germany — 2Max-Planck-Institute for Molecular Cell Biology and Genetics, Dresden, Germany — 3Biotechnology Center, Technical University Dresden, Dresden, Germany
The body plan and organs of most animal species show a consistent handedness. During the development of these organisms and structures, chiral flows of molecules and cells in thin fluid films are often observed. These flows suggest the presence of torques. In particular, chiral flows in the acto-myosin cortex of the Caenorhabditis elegans embryo have been linked to active torque generation by the acto-myosin system. Due to angular momentum conservation, a torque in such an active surface has to be balanced by an opposing torque somewhere in the surrounding. Hence, the material properties of the environment and its interaction with the active surface are of crucial importance. Here, we study ensembles of torque dipoles in viscous environments. We demonstrate that the resulting flow fields in the active surface show striking differences to torque generation on a rigid substrate. We also study the dynamics of torque dipoles in the presence of active isotropic and nematic stresses. We observe that the presence of even weak torque dipoles can bias chiral symmetry breaking in active nematics. We then ask the question, whether the mutual action of nematic stress and torque dipoles can account for the appearance of chiral flows in avian embryos in the absence of cilia.