טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentShevah Jonathan
SubjectHydra Regeneration under Mechanical Forces by a Magnetic
Field
DepartmentDepartment of Physics
Supervisors Professor Erez Braun
Professor Kinneret Keren


Abstract

Morphogenesis is the process leading to the emergence of patterned functional tissues in living systems. This is a complex process, involving many physical and biochemical mechanisms through many length scales. In this work we utilize the Hydra, a millimeter-sized freshwater polyp, to study the regeneration process under the influence of mechanical forces. The Hydra body is a cylindrical tube, made of two layers of epithelial cells, with a head at one end and a foot at the other end. The Hydra is particularly known for its remarkable regeneration capabilities: starting from a small fragment of Hydra tissue or a cell aggregate, an entire animal regenerates within a couple of days. The initial step in regeneration is the formation of a hollow spheroid, which undergoes extensive shape fluctuations as it develops into a small Hydra. Throughout this process, the Hydra tissue experiences passive forces and exerts active forces. We attach superparamagnetic beads to the Hydra tissue and place it under magnetic fields to exert an external force on the tissue during the regeneration process. In our work we find that the application of force on Hydra tissue can delay the regeneration time and even block regeneration. We observed similar tissue deformations in samples under forcing and in control samples, suggesting that the applied force does not prevent active internal force generation by the tissue during regeneration.