Lecturer: Erez Braun, Physics, Technion
Abstract:
Morphogenesis, the emergence of well-defined patterns of functional tissues during development, is carried out by the collective dynamics of multiple physical and biochemical processes at different levels of organization, from local molecular events to large-scale chemical, electrical and mechanical stress fields. A major question is: how do all the underlying processes converge to the functional body plan typical of a specific organism? We propose that morphogenesis is robust in the face of fluctuating and changing conditions, due to synergistic dynamics of mechanical, electrical and bio-signaling processes which evolve simultaneously as coupled fields. We take advantage of a unique multicellular organism, Hydra, famous for its extraordinary regeneration capabilities, to advance our biophysical understanding of morphogenesis. I will discuss our recent experiments on Hydra regeneration, shedding light on the role of the internal force generation in stabilizing the body axis. We apply physical constraints to gain insight on mechanical feedbacks and utilize various external force fields, hydrodynamic shear flows, electric fields and magnetic forces on beads attached to the regenerating tissue, to induce spatio-temporal modes during the regeneration process. Perturbing the regeneration process and imposing external constraints enable us to expose alternative developmental trajectories towards the construction of a physical framework for morphogenesis.