Effects of leucine starvation on control of ribonucleic acid synthesis in strains of Bacillus subtilis differing in deoxyribonucleic acid regulation.

When starved for leucine, strains of Bacillus subtilis do not complete chromosome replication to the terminus. The amount of deoxyribonucleic acid (DNA) made poststarvation is characteristic of the strain. In this study, four strains differing in their DNA response were examined for ribonucleic acid (RNA) regulation during leucine starvation. Each of the strains was judged to be stringent for RNA control based on the amount of RNA made poststarvation. Sucrose gradient profiles on RNA made with and without leucine starvation support this conclusion. Accumulation of guanosine tetraphosphate during leucine starvation showed no correlation with the amount of DNA synthesized. We concluded that modulation control of DNA synthesis during leucine starvation is independent of RNA control.