The GTP pool in Bacillus brevis and its significance for sporulation.

The GTP pool of Bacillus brevis as well as that of other nucleotides is highly sensitive to all kinds of environmental changes like the cell transfer procedures or nutrient depletion of the cells. In growing cultures, as well as in cells transferred from rich to nitrogen-deficient medium, the nucleotide pool decreases significantly. This decrease is followed by the onset of sporulation only when cells are allowed to produce the peptide antibiotic tyrocidine or if tyrocidine is added to the culture.