Disappearance of Guanosine 5'-Diphosphate 3'-Diphosphate in Bacillus subtilis Vegetative Cells upon Carbon Source Deprivation

Abstract

Bacillus subtilis was grown in a nutrient medium, mNSMP, and a synthetic medium, mS 6 (C), in which spore formation was initiated after vegetative growth and exhaustion of carbon source or glucose. The amounts of intracellular phosphorylated compounds were analyzed at intervals by 2M formic acid extraction and polyethyleneimine (PEI)-cellulose thin-layer chromatography followed by autoradiography. A hyperphosphorylated nucleotide, guanosine 5'-diphosphate 3'-diphosphate (ppGpp), was accumulated in cells during vegetative growth in both mNSMP and mS 6 (C), and then the nucleotide was degraded upon initiation of sporulation in both cases. Furthermore, after the nucleotide had disappeared in cells cultivated in mS 6 (C) upon exhaustion of the carbon source, it could be reformed in the sporulating cells by addition of glucose to the medium. These results suggest that the ppGpp in vegetative cells may function in the regulation of B. subtilis sporulation.