https://doi.org/10.1140/epjb/e20020142
Hydrodynamics and cell motion during the rounding of two dimensional hydra cell aggregates
1
Département de Physique des Matériaux,
Université Claude Bernard – Lyon I, 43 boulevard du 11 Novembre
1918, 69622 Villeurbanne Cedex, France
2
Tohoku Institute of Technology Yagiyama-Kasumi, Taihaku, 983, Sendai, Japan
Corresponding author: a rieu@dpm.univ-lyon1.fr
Received:
21
December
2001
Published online: 15 May 2002
Using a two dimensional experimental geometry, we study
hydrodynamics and cell motion during the rounding-up of three
kinds of hydra aggregates (ectodermal, endodermal and
mixed). The relaxation of initially elongated aggregates toward
a circular shape is exponential and the relaxation time is
proportional to the aggregate size as expected from hydrodynamics
laws. As for viscous liquids, aggregate rounding is driven by
tissue surface tensions σ and resisted by tissue viscosity
η. The ratio is the same for the three kinds of
aggregates. With a reasonable value
mN/m, we obtain an
estimate larger than 104 Pa s for the tissue viscosity. Cell
motion during rounding is strongly cooperative and cell
displacements exhibit some specific patterns in each aggregate.
These results point out the role of adhesive bonds in the observed
kinetics.
PACS: 87.18.Ed – Aggregation and other collective behavior of motile cells / 87.17.Jj – Cell locomotion; chemotaxis and related directed motion / 87.19.Tt – Rheology of body fluids
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2002