Induction of Sporulation in Bacillus brevis

Publisher Website
Google Scholar
Abstract
Under conditions of severe N starvation, brought about by nutritional shift-down, B. brevis ATCC 8185 was unable to sporulate unless supplemented with the peptide antibiotic tyrocidine. The induction of sporulation was highly specific for tyrocidine and required only very low concentrations of the peptide (5 .mu.M). Tyrocidine-induced sporulation was accompanied by the typical sporulation-specific events (e.g., extracellular protease production and dipicolinate synthesis) and the formation of linear gramicidin. The addition of tyrocidine produced acute inhibition of RNA synthesis that was followed by a limited activation of transcription near the time of onset of linear gramicidin synthesis, when the first sporulation-specific changes were observed. These results provide direct evidence for a role of tyrocidine in sporulation of B. brevis and suggest that the action of the peptide antibiotic may involve the control of transcription. Such a notion is supported by earlier studies on the effects of tyrocidine and linear gramicidin on purified RNA polymerase.