Synchronous growth of Escherichia coli after treatment with fluorophenylalanine.

Treatment of exponentially growing Escherichia coli cells with the amino acid analogue, p-fluorophenylalanine (FPA), resulted in a decrease in the amount of deoxyribonucleic acid (DNA) present per cell. A minimum DNA content per cell was reached approximately 80 min after addition of FPA to the culture. After this time the DNA per cell rose to the level of the untreated cell. When an FPA-treated culture was resuspended in fresh medium containing no FPA 80 min after addition of the analogue, the increases in cell number and DNA became synchronous. Ribonucleic acid was synthesized immediately and continuously throughout the cell cycle, except during periods of DNA synthesis and cell division.