Anomalous diffusion and non-Gaussian velocity distribution of Hydra cells in cellular aggregates

We study the canter of mass motion of single endodermal Hydra cells in two kinds of cellular aggregates: endodermal and ectodermal. The mean square displacement displays anomalous super-diffusion with (x(2)) similar to t(alpha) where alpha > 1. The velocity distribution function is non-Gaussian and fits well the q-distribution function of velocities within the framework of the non-extensive thermostatistics proposed by Tsallis. Our results indicate that cell motion in two-dimensional cellular aggregates can be described by a correlated-type anomalous diffusion. (C) 2001 Published by Elsevier Science B.V.