1981 Volume 27 Issue 2 Pages 173-183
Synchronized cells of Bacillus subtilis 168 (Thy His) and its derivative, DNA elongation mutant ts526 were used to study the effects of the inhibition of DNA synthesis on the cell-cycle-specific events. When DNA synthesis of strain 168 was inhibited by thymine deprivation from the beginning of the cell cycle, septum formation and cell division were possible in the ongoing cell cycle but not in the forthcoming one. The results of the upward shift of temperature experiments with ts526 supported the above observations. Fluctuation of penicillin sensitivity and stepwise increase in peptidoglycan synthesis during the cell cycle, which were observed in the presence of DNA synthesis, occurred only in the ongoing cell cycle in the absence of DNA synthesis. We at least suggest that these cell-cycle-specific events are intimately connected with septum formation and cell division, and are not affected by DNA inhibition in the ongoing cell cycle.