Dependence of local cell density on concentric ring colony formation by bacterial species Bacillus subtilis

Hirotoshi Shimada*, Takemasa Ikeda, Jun Ichi Wakita, Hiroto Itoh, Sayuri Kurosu, Fumiko Hiramatsu, Michio Nakatsuchi, Yoshihiro Yamazaki, Tohey Matsuyama, Mitsugu Matsushita

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)


The formation of concentric ring-like colonies by bacterial species Bacillus subtilis has been investigated, focusing our attention on the effect of local cell density upon the bacterial motility: (i) Neither any chemicals nor a pacemaker at the center of the ring takes part in the concentric ring formation. (ii) Phase entrainment between two colonies having different phase of concentric ring does not occur. (iii) From the measurement of lag-phase time when varying the initial cell density, the start of the first migration phase is found to depend on the cell density. (iv) When cutting the part of a colony which is behind a migration phase just after the start of migration, the migration phase becomes shorter. On the other hand, the following consolidation phase becomes longer. (v) By the replica-printing method, active bacteria move collectively from inside to outside of the outermost consolidation terrace. Our present experimental results are qualitatively consistent with the results of the other bacterial species P. mirabilis, although the individual cell motility is quite different from each other. The present results suggest that the essential factor of the change of the bacterial motility of B. subtilis during concetric ring formation is the local cell density.

Original languageEnglish
Pages (from-to)1082-1089
Number of pages8
Journaljournal of the physical society of japan
Issue number4
Publication statusPublished - 2004 Apr


  • B. subtilis
  • Bacterial colony
  • Bacterial motility
  • Cell density
  • Concentric ring pattern
  • Replica-printing

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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