Transduction of flagellar characters in Salmonella

SUMMARY: Phage lysates of a salmonella strain can transduce flagellar characters from that strain to a second strain which absorbs the phage. Non-motile strains treated with lysates o other strains produced stable motile forms detected as spreading swarms in semi-solid agar. O strains of known species produced swarms with the H antigens characteristic of theirown species, and the species of previously untypable O isolates could be inferred from the H antigens of their induced swarms. The production of swarms by O strains when treated with lysates of other O strains divided nine Salmonella typhimurium O strains into six interacting groups; there are therefore at least six non-homologous genetic factors, mutation of any of which may cause absence of flagella, thus masking other genes which control H antigenic specificity. Two flagellated but non-motile strains produced motile forms when treated with lysates of other strains, or of each other. At least two genes concerned with locomotor function are thus recognized. All the motile derivatives of one O strain spread very slowly through semi-solid agar; the ability to spread rapidly could be transduced to them by a second exposure to a lysate. In exceptional instances two flagellar characters were simultaneously transduced: three O strains sometimes acquired a flagellar antigen from the donor strain at the same time as the H character; another O strain sometimes acquired simultaneously flagellation and the slow-spreading character. There are therefore many distinct genes controlling the presence, antigenic character and function of the flagella. They may form part of an ordered gene array in which pairs of genes which are sometimes simultaneously transduced by a single phage particle are presumably closely linked.