Does the eclipse limit bacterial nucleoid complexity and cell width?

Arieh Zaritsky, Avinoam Rabinovitch, Chenli Liu, Conrad L. Woldringh

Research output: Contribution to journalReview articlepeer-review

6 Scopus citations


Cell size of bacteria M is related to 3 temporal parameters: chromosome replication time C, period from replication-termination to subsequent division D, and doubling time τ. Steady-state, bacillary cells grow exponentially by extending length L only, but their constant width W is larger at shorter τ‘s or longer C's, in proportion to the number of chromosome replication positions n (= C/τ), at least in Escherichia coli and Salmonella typhimurium. Extending C by thymine limitation of fast-growing thyA mutants result in continuous increase of M, associated with rising W, up to a limit before branching. A set of such puzzling observations is qualitatively consistent with the view that the actual cell mass (or volume) at the time of replication-initiation Mi (or Vi), usually relatively constant in growth at varying τ′s, rises with time under thymine limitation of fast-growing, thymine-requiring E. coli strains. The hypothesis will be tested that presumes existence of a minimal distance lmin between successive moving replisomes, translated into the time needed for a replisome to reach lmin before a new replication-initiation at oriC is allowed, termed Eclipse E. Preliminary analysis of currently available data is inconsistent with a constant E under all conditions, hence other explanations and ways to test them are proposed in an attempt to elucidate these and other results. The complex hypothesis takes into account much of what is currently known about Bacterial Physiology: the relationships between cell dimensions, growth and cycle parameters, particularly nucleoid structure, replication and position, and the mode of peptidoglycan biosynthesis. Further experiments are mentioned that are necessary to test the discussed ideas and hypotheses.

Original languageEnglish
Pages (from-to)267-275
Number of pages9
JournalSynthetic and Systems Biotechnology
Issue number4
StatePublished - 1 Dec 2017


  • Bacterial cell cycle
  • Eclipse
  • Growth
  • Nucleoid complexity
  • Replication and division
  • Size and dimensions

ASJC Scopus subject areas

  • Structural Biology
  • Biomedical Engineering
  • Applied Microbiology and Biotechnology
  • Genetics


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