[Lysogenic conversion of cholera vibrios]

As a result of ultraviolet irradiation and treatment with nitrosmethyl urea, mitomycin C, ascorbic acid and sarcolysin, the elimination of prophage from wild lysogenic Vibrio cholerae strains, biotype El Tor, has been achieved. The elimination of prophage was accompanied by a change in the biological properties of the vibrios, and some of these biological properties were found to be correlated with the lysogenization of Vibrio cholerae by the definite races of temperate phages. Only a few races of type II phages, whose genome was responsible for the serological characteristics of the strain, its sensitivity to cholera diagnostic phages and polymyxin, were capable of conversion.