%0 Journal Article %A Evans, J. Barbara %T Preparation of Synchronous Cultures of Escherichia coli by Continuous-flow Size Selection %D 1975 %J Microbiology, %V 91 %N 1 %P 188-190 %@ 1465-2080 %R https://doi.org/10.1099/00221287-91-1-188 %I Microbiology Society, %X Methods of producing synchronous cultures in eukaryotic and prokaryotic organisms by both induction and selection synchrony have been described in detail by Mitchison (1971) . Induction synchrony of bacteria by heat shock ( Smith & Pardee, 1970 ) and by starvation ( Cutler & Evans, 1966 ; Inouye & Pardee, 1970 ) have produced synchronous divisions through at least two cell cycles. The methods of induction synchrony are likely to produce disturbed metabolism, so that where possible synchronous cultures obtained by selection procedures are preferable. Selection synchrony of bacteria by sucrose density centrifugation ( Mitchison & Vincent, 1965 ) and by membrane elution ( Helmstetter & Cummings, 1964 ) produce synchronous cultures with little metabolic disturbance. The major disadvantage of the density gradient centrifugation procedure is that it takes a considerable time, which would probably exceed a single cell cycle in experiments involving short generation times. The membrane elution technique is applicable only to a narrow range of strains of Escherichia coli ( Cummings, 1970 ). The method of selection synchrony described here provides a rapid method for the selection of metabolically undisturbed, large-scale synchronous cultures of E. coli. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-91-1-188