Inheritance of the O Antigens of Salmonella Groups B and D

Abstract

SUMMARY: 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—4/9 locus thus defined was rather closely linked to his, the locus for histidine biosynthesis. The gene O—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 O—5 locus was also found to be linked to O—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 O-locus concerned with the synthesis of the specific side-chains of the somatic lipopolysaccharide, which perhaps includes the rou-B locus of Subbaiah & Stocker (1964).