Variations in the cell cycle of slow-growing Escherichia coli 15T-.

DNA synthesis was measured via 3H-thymidine pulses, and patterns of incorporation were compared to cell number increases during synchronous division of Escherichia coli 15T- (555-7) in M9.01% aspartate. The timing of chromosome initiation, duration of chromosome synthesis, and the D period were found to vary over the three cycles of division analysed. In addition, the D period measured by comparing 3H-thymidine incorporation and concomitant division, differed from D period measurements made by timing division cessation in DNA synthesis inhibitors.