Inheritance of the O Antigens of Salmonella Groups B and D

Abstract

The inheritance of the O antigens of Salmonella was studied by Hfr X F- crosses of strains of groups B (antigens 4,5,12) and D (antigens 9,12). The partial antigens 4 and 9 behaved as if determined by allelic loci, in the sense that all recombinants had either antigen 4 or antigen 9; never both or neither of them. The O[long dash]4/9 locus thus defined was rather closely linked to his, the locus for histidine biosynthesis. The gene O[long dash]5 determining the presence or absence of partial antigen 5 (an O-acetyl group on a galactose unit) in group B was very probably introduced into a number of 9,12 recombinants. No antigen 5 appeared. The 0[long dash]5 locus was also found to be linked to 0[long dash]4/9 and his but the linkage was less close than that between O-4/9 and his. It is suggested that the loci O-4/9 and possibly O-5 are part of a large 0-locus concerned with the synthesis of the specific side-chains of the somatic lipopolysaccharide, which perhaps includes the rou-B locus of Subbaiah and Stocker.