Studies on the Gram-Negative Cell Wall, I. Evidence for the Role of 2-Keto-3-Deoxyoctonate in the Lipopolysaccharide of Salmonella Typhimurium

Abstract

The cell wall lipopolysaccharides which determine the somatic (o) antigen specificities of Salmonella typhimurium and E. coli consist of highly branched, complex polysaccharides linked to a glucosamine-containing lipid. ' The polysaccharide moiety may contain as many as 6 neutral sugars; for example, L-glycero-D-mannoheptose, glucose, galactose, mannose, rhamnose, and abequose (3,6-dideoxy-Dgalactose) have been identified2' I as components of the polysaccharide of S. typhimurium. The polysaccharides are thought'to consist of an internal core structure, possibly similar in all enteric bacteria, to which are attached complex side chains bearing group or species specific antigenic determinants. New insight into both structure and mechanism of biosynthesis of these polysaccharides has recently been obtained3' 5 through the use of mutant organisms deficient in the synthesis of specific nucleotide sugars. It was first shown by Nikaido5' 6 that incomplete polysaccharides are formed by mutants which are unable to synthesize UDPgalactose as a result of loss of the enzyme, UDP-galactose4-epimerase. The polysaccharides formed by these mutants characteristically lack not only galactose, but also certain other sugars present in the normal polymers, and appear to represent the innermost core region of the wild-type polysaccharide. Previous studies in our laboratory3 on a UDP-galactose-4-epimeraseless strain of S. typhimurium have shown that the incomplete "core" polysaccharide formed by this mutant contains glucose, L-glycero-D-mannoheptose, and phosphate. It has now been found that this polysaccharide also contains 2-keto-3-deoxyoctonate (KDO),7 recently identified by Heath and Ghalambor8 as a component of the lipopolysaccharide of

Modulations in lipid A and phospholipid biosynthesis pathways influence outer membrane protein assembly in Escherichia coli K‐12

“…Pulse-chase labelling experiments and immunoprecipitation were carried out as described previously (Misra, 1993). LPS was quantified by measuring 2-keto-3-deoxyheptonic acid (KDO) as described previously (Weissbach and Hurwitz, 1959;Osborn, 1963). Phospholipids were quantified by modifying a method described previously (Nishijima and Raetz, 1979).…”

Characterization of Lipopolysaccharides Isolated from Agrobacterium tumefaciens

“…Samples were digested in H2S04/H202 and their phosphorus content was measured by the method of Bartlett (1959). 2-Keto-3-deoxyoctonate (KDO) was determined as described by Osborn (1963), and rhamnose and heptose by the method of Dische (1963) using D-manno-heptulose (Sigma) and L-rhamnose (Fluka, Buchs, Switzerland) as standards. Glucose was determined by the glucose oxidase test (Boehringer) after hydrolysis in 1 M-HCl (100 "C; 4 h).…”

Enzyme-linked immunosorbent assay with a Salmonella enteritidis antigen for differentiating infected from vaccinated poultry

“…The protein and LPS contents of these four antigenic preparations were measured by the Lowry [18] and ketodesoxyoctonate (KDO) assays [22,29], respectively.…”