Some Properties of a New Bacteriocin Formed by Bacillus megaterium

Abstract

Summary: A new bacteriocin, megacin C, was recognized in certain strains of Bacillus megaterium; it was initially observed as the agent responsible for killing sensitive organisms in mixed culture. The bacteriocin was liberated during growth of cultures; but later, after reaching a maximum value, it disappeared from the culture media. Megacin C was produced by strains already known to produce another bacteriocin, megacin A. The activity spectra of the two megacins differed markedly and non-megacin A (MA -) mutants still produced megacin C. A preliminary grouping of megacin types is proposed. Megacin A is comparable to the original megacin first studied by Ivánovics & Alföldi (1954). Megacin A produced inhibition zones surrounding colonies on solid medium but its formation in liquid medium required induction with ultraviolet (u.v.) radiation. Megacin B, whose activity spectra differed from those of megacins A and C, can be detected only on a solid medium; it is not formed in liquid culture even after u.v.-irradiation. Megacin C can be detected only on a particular solid medium and its formation in liquid media is not induced by u.v.-irradiation.