Synchronized cell division and DNA synthesis in a Lactobacillus acidophilus mutant.

Withdrawal and subsequent restoration of deoxyriboside to a deoxyriboside-requiring mutant leads to synchronous cell division. There is a time lag between restoration and the first synchronous division; during this time the amount of deoxyribonucleic acid (DNA) per cell increases in stepwise fashion, and tnass per cell increases linearly with time. The onset of cell division is heralded by cessation of DNA synthesis and an abrupt increase in rate of mass synthesis.