[The biological activity and physicochemical properties of a new bacteriocin from a strain of Pseudomonas cepacia 5779].

Pseudomonas cepacia 5779 bacteriocin (cepaciacin) whose producer was revealed due to application of the special screening system has been studied for its certain biological and physicochemical properties. Possessing a narrow range of action, it inhibits only the P. cepacia strains. Its biosynthesis occurs more intensely on the rich nutrient media, the highest quantities of cepaciacine being revealed at the terminal stage of the produced log growth. UV irradiation or mitomycin C introduction into the medium stimulated biosynthesis of this bacteriocin. Cepaciacin P. cepacia 5779 is a complex consisting of several protein subunits and carbon part. The protein-carbohydrate ratio is 3:1. The molecular weight of the complex is 1.8 x 10(6) Da. Lipopolysaccharides isolated from the indicator strain being added, cepaciacine loses its activity. This bacteriocin is stable in the narrow range of pH, thermolabile, decomposes under the effect of proteases and is, evidently, a representative of a new type of the bacteriocin-like substances.