title: Instructive simulation of the bacterial cell division cycle.
abstract: The coupling between chromosome replication and cell division includes temporal and spatial elements. In bacteria, these have globally been resolved during the last 40 years, but their full details and action mechanisms are still under intensive study. The physiology of growth and the cell cycle are reviewed in the light of an established dogma that has formed a framework for development of new ideas, as exemplified here, using the Cell Cycle Simulation (CCSim) program. CCSim, described here in detail for the first time, employs four parameters related to time (replication, division and inter-division) and size (cell mass at replication initiation) that together are sufficient to describe bacterial cells under various conditions and states, which can be manipulated environmentally and genetically. Testing the predictions of CCSim by analysis of time-lapse micrographs of Escherichia coli during designed manipulations of the rate of DNA replication identified aspects of both coupling elements. Enhanced frequencies of cell division were observed following an interval of reduced DNA replication rate, consistent with the prediction of a minimum possible distance between successive replisomes (an eclipse). As a corollary, the notion that cell poles are not always inert was confirmed by observed placement of division planes at perpendicular planes in monstrous and cuboidal cells containing multiple, segregating nucleoids.
authors.affiliation: Life Sciences Department, Ben-Gurion University of the Negev, POB 653, Be'er-Sheva 84105, Israel.
authors.forename: Arieh
authors.initials: A
authors.lastname: Zaritsky
authors.affiliation: FAS Center for Systems Biology, Harvard University, 52 Oxford St, Cambridge, MA 02138, USA.
authors.forename: Ping
authors.initials: P
authors.lastname: Wang
authors.affiliation: Molecular Cytology, Faculty of Science, University of Amsterdam, NL1098 XH, The Netherlands.
authors.forename: Norbert O E
authors.initials: NOE
authors.lastname: Vischer
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002453:Cell Cycle / Q000502:physiology*; D002876:Chromosomes, Bacterial; D003198:Computer Simulation; D004261:DNA Replication; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000166:cytology / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D008954:Models, Biological
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial