Eur. Phys. J. E 3, 101-110
Nematic order-disorder state transition in a liquid crystal analogue formed by oriented and migrating amoeboid cells
R. Kemkemer1 - V. Teichgräber1 - S. Schrank-Kaufmann1 - D. Kaufmann2 - H. Gruler1
1Department of bioPhysics, University of Ulm, D-89069 Ulm,
Germany
2 Department of Human Genetics, University of Ulm, D-89069 Ulm, Germany
hans.gruler@physik.uni-ulm.de
Received 2 August 1999 and Received in final form 5 January 2000
Abstract
In cell culture, liquid crystal analogues are formed by
elongated, migrating, and interacting amoeboid cells. An apolar
nematic liquid crystal analogue is formed by different cell types
like human melanocytes (=pigment cells of the skin), human
fibroblasts (=connective tissue cells), human osteoblasts
(=bone cells), human adipocytes (=fat cells), etc. The nematic
analogue is quite well described by i) a stochastic machine
equation responsible for cell orientation and ii) a self-organized
extracellular guiding signal, E2, which is proportional to the
orientational order parameter as well as to the cell density. The
investigations were mainly made with melanocytes. The transition to
an isotropic state analogue can be accomplished either by changing
the strength of interaction (e.g. variation of the cell
density) or by influencing the cellular machinery by an externally
applied signal: i) An isotropic gaseous state analogue is observed
at low cell density (
melanocytes/mm2) and a
nematic liquid crystal state analogue at higher cell density. ii)
The nematic state analogue disappears if the bipolar shaped
melanocytes are forced to become a star-like shape (induced by
colchicine or staurosporine). The analogy between nematic liquid
crystal state analogue formed by elongated, migrating and
interacting cells and the nematic liquid crystal phase formed by
interacting elongated molecules is discussed.
PACS
87.18.-h Multicellular phenomena - 87.18.Ed Aggregation
and other collective behavior of motile cells
- 64.70.-p Specific phase transitions
Copyright EDP Sciences, Società Italiana di Fisica, Springer-Verlag
