Transduction with phage PI in Salmonella typhimurium.

Abstract

Two types of mutants of Salmonella typhimurium LT-2 with increased recipient abilities were isolated by treatment with N-methyl-N′-nitro-N-nitrosoguanidine followed by the transfer of an R factor from Escherichia coli K-12 and its subsequent elimination with acriflavine1. One of them, which was obtained in a single-step selection, was named Rfer1 (fer = fertile) and the other type isolated from Rfer1 was called Rfer2. Rfer1 mutants showed considerably higher recipient abilities than the wild type (Rinfer) (infer = infertile), and Rfer2 mutants acted as better recipients than Rfer1. Rfer1 mutants were considered unrestricted and unmodified and Rfer2 strains were assumed to have mutations of some properties of the cell surface in addition to the Rfer1 mutations because of the rough colonial morphology of Rfer2 mutants. In fact, Rfer2 mutants were found to be sensitive to a number of coliphages, including P1 to which the wild type and Rfer1 strains are resistant. Thus transduction with phage P1 has become possible in S. typhimurium and between E. coli and S. typhimurium.