Model-based definition of population heterogeneity and its effects on metabolism in sporulating Bacillus subtilis

Mineo Morohashi, Yoshiaki Ohashi, Saeka Tani, Kotaro Ishii, Mitsuhiro Itaya, Hideaki Nanamiya, Fujio Kawamura, Maseru Tomita, Tomoyoshi Soga

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

The soil bacterium Bacillus subtilis forms dormant, robust spores as a tactic to ensure survival under conditions of starvation. However, the sporulating culture includes sporulating and non-sporulating cells, because a portion of the cell population initiates sporulation in wild-type strain. We anticipated that the population effect must be considered carefully to analyse samples yielding population heterogeneity. We first built a mathematical model and simulated for signal transduction of the sporulation cue to see what mechanisms are responsible for generating the heterogeneity. The simulated results were confirmed experimentally, where heterogeneity is primarily modulated by negative feedback circuits, resulting in generation of a bistable response within the sporulating culture. We also confirmed that mutants relevant to negative feedback yield either sporulating or non-sporulating subpopulations. To see the effect of molecular mechanism between sporulating and non-sporulating cells in distinct manner, metabolome analysis was conducted using the above mutants. The metabolic profiles exhibited distinct characteristics with time regardless of whether sporulation was initiated or not. In addition, several distinct characteristics of metabolites were observed between strains, which was inconsistent with previously reported data. The results imply that careful consideration must be made in the interpretation of data obtained from cells yielding population heterogeneity.

Original languageEnglish
Pages (from-to)183-191
Number of pages9
JournalJournal of biochemistry
Volume142
Issue number2
DOIs
Publication statusPublished - 2007 Aug 1

Keywords

  • Bacillus subtilis
  • Heterogeneity
  • Metabolome
  • Sporulation

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology

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