PROBABLE IDENTITY OF A GROUP D HEMOLYSIN WITH A BACTERIOCINE.

Brock, Thomas D. (Indiana University, Bloomington) and Joseph M. Davie. Probable identity of a group D hemolysin with a bacteriocine. J. Bacteriol. 86:708-712. 1963.-All strains of Streptococcus zymogenes (S. faecalis var. zymogenes) produce a bacteriocine which is active against lactic acid bacteria and most other grampositive bacteria. Mutants which have lost the hemolytic characteristic lose at the same time their bacteriocine-producing ability. A strain which was resistant to the bacteriocine but which was nonhemolytic and nonbacteriocinogenic was irradiated, and two hemolytic mutants were isolated from it. These mutants were also bacteriocinogenic. Thus, the two activities are gained or lost together by mutation. Both activities are destroyed by chloroform vapors and are antagonized by lecithin. Both activities are destroyed at the same rate by treatment at 45 C under mildly acid conditions, and both activities are stable when heated in agar. The two activities are produced in parallel during the growth cycle, and disappear in parallel. The possible ecological role of a substance which is both a hemolysin and a bacteriocine is discussed.