DNA SYNTHESIS DURING DIVISION CYCLE OF RAPIDLY GROWING ESCHERICHIA COLI B/R

The rate of DNA synthesis during the division cycle of Escherichia coli B r growing with doubling times between 22 and 40 minutes has been determined by the membrane-selection technique described previously (Helmstetter, 1967). The results indicate that the cell age at which rounds of DNA replication begin is variable and depends upon the growth rate, and that the time for a complete round of replication is constant and independent of the growth rate. It is suggested that in rapidly growing E. coli B r a new round of replication begins before the previous round has ended. © 1968.