Mucopeptide metabolism during growth and sporulation in Bacillus megaterium.

A mutant of Bacillus megaterium lacking the aspartate P-semialdehyde-pyruvate-condensing enzyme and mesodiaminopimelic acid decarboxylase has been used in a study of mucopeptide metabolism during growth and sporulation. The absolute requirement for both diaminopimelic acid and lysine in this mutant guarantees that exogenous labeled diaminopimelic acid is incorporated specifically into mucopeptide greatly facilitating such studies. During the vegetative growth phase, no turnover of mucopeptide was observed. Upon glucose exhaustion and the initiation of sporulation, vegetative cell mucopeptide synthesis ceased. The mother cell wall remained quiescent throughout the sporulation sequence. Some 3 hours after the end of vegetative cell growth, spore-specific mucopeptide synthesis began and continued for approximately 6 hours. Sporulation was terminated by lysis of mother cell wall which released free spores into the medium.