Adaptation-induced Collective Dynamics of Micro-organisms

 Maiko Ogata, Yoshinori Hayakawa, et al., January 2008
We investigate the behavior of a single-cell protozoan in a narrow tubular ring. This environment forces them to swim under a one-dimensional periodic boundary condition. Above a critical density, single-cell protozoa aggregate spontaneously without external stimulation. The high-density zone of swimming cells exhibits a characteristic collective dynamics including translation and boundary fluctuation. We analyzed the velocity distribution and turn rate of swimming cells and found that the regulation of the turing rate leads to a stable aggregation and that acceleration of velocity triggers instability of aggregation. These two opposing effects may help to explain the spontaneous dynamics of collective behavior. We also propose a stochastic model for the mechanism underlying the collective behavior of swimming cells.

[1] Adaptation-induced collective dynamics of a single-cell protozoan,  Maiko Ogata, Tsuyoshi Hondou, Yoshinori Hayakawa, Yoshikatsu Hayashi and Ken Sugarawa, Physical Review E 77 011917 (2008). (preprint)

* The same article is accessible via Virtual Journal of Biological Physics Research ( February 1, 2008 issue).