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The complete structure for the core oligosaccharide region of the water-insoluble low-Mr, lipopolysaccharide of Campylobacter jejuni serotype O:3 from phenol/water extraction of bacterial cells was assigned through studies on derivatives of the liberated oligosaccharide. Structure determinations were performed using 1H-NMR and 31P-NMR spectroscopies, methylation analysis supported by fast-atom-bombardment mass spectrometry, and Smith degradation experiments. It was concluded that the complete chains in the core oligosaccharide had the following structure in which a proportion of the terminal residues were phosphorylated: [This equation cannot be presented in ASCII format] From a similar series of experiments, it was concluded that an associated polysaccharide, which was isolated from the water phase of the phenol/water extracts, had the following repeating unit in which a proportion of the previously unknown L-glycero-D-ido-heptose (L-α-D-ido-Hep) residues were present as 3-hydroxypropanoyl esters, and were not covalently linked to the lipopolysaccharide: [This equation cannot be presented in ASCII format] [ABSTRACT FROM AUTHOR]

Complete structures, including the location of N-acetylneuraminic acid (Neu5Ac) residues, were assigned for the core regions of Campylobacter jejuni serotypes O:1, O:4, and O:23 and O:36 lipopolysaccharides (LPS). In continuation of earlier studies, structure determinations of liberated oligosaccharides and, where necessary, of intact LPS, were by [sup1]H-NMR spectroscopy, Smith degradation, chromium trioxide and enzymic degradations, in conjunction with methylation studies supported by fast-atom-bombardment mass spectrometry and linkage analyses by gas chromatography/mass spectrometry. It was concluded on the basis of the following structures, in which each was linked 1→5 to a terminal 3-deoxy-D-manno-octulosonic acid residue, that the core regions with qualitatively similar sugar compositions showed serotypic differences in one or more of their sequences, linkage types, and anomeric configurations: (formula???).The outer regions of each structure carry Neu5Ac residues linked 2→3 to available β-D-Galp residues and show striking similarities with various glycosphingolipids of the ganglioside family. However, Neu5Ac epitopes are not apparently involved in determining serospecificity. [ABSTRACT FROM AUTHOR]

The complete structure for the core region of Campylobacter jejuni serotype O:2 lipopolysaccharide (LPS) was assigned through studies on derivatives of the liberated oligosaccharide (OS 2) and the intact LPS. Structure determinations were performed using [sup1]H-NMR spectroscopy, methylation studies supported by fast-atom-bombardment mass spectrometry and linkage analysis by gas chromatography/mass spectrometry, Smith degradation, and oxidation with chromium trioxide. It was concluded that complete oligosaccharide chains had the following structure: [formula] [ABSTRACT FROM AUTHOR]

Lipopolysacharides (LPS) from antigentically different strains assigned to seroroups O:3 and O:6 of Helicobacter pylori were isolated as water-soluble material of high Mr and as water-insoluble gels of low Mr. Chemical and spectroscopic analyses of the soluble LPS and oligosaccharides liberated from the water-insoluble gels led to proposed structures with Lewis (Le) antigen determinants terminating regular repeating units of different types, linked in turn to inner core regions of invariable structure. The O:6 LPS has two populations of related molecules with chains of 3-linked D-glycero-α-D-manno-heptose residues similar to those in the MO19 strain, one with and the other without a single terminal Lewis (Ley) epitope. In contrast, in the O:3 LPS. Lewis (Lex and Ley epitopes terminate a partially fucosylated N-acetyllactosaminoglycan, but a heptan chain similar to that in the O:6 LS was shown to connect the outer chains to the inner core. These PS provide examples of the molecular mimicry of cell-surface glycoconjugates. Structural variations of LPS between strains, and differences in some aspects of structure within the strains, between high Mr and low Mr LPS indicate a class of LPS whose mechanisms of biosynthesis lead to overall architectures different from those characteristics of most LPS from enteric bacteria. [ABSTRACT FROM AUTHOR]

The 'C-mycosidic' glycopeptidolipid typing antigens from all serovars in the Mycobacterium avium/M, intracellulare/M, scrofulaceum complex have been examined to varying extents. Detailed analysis of those from serovars 8, 9, 16 and 25 show that the antigens consist of short acetylated oligosaccharides linked to a common fattyacyl-peptidyl-O-(3,4-di-O-methylrhamnose) 'core'. The oligosaccharide units, in a form suitable for chemical studies, were liberated as oligosaccharide alditols on treatment of the glycopeptidolipids with alkaline borohydride solution. The alditol in the reduced oligosaccharides from all sources is 6-deoxytalitol. Moreover rhamnose is also always present, indicating that a 'basal' disaccharide, rhamnosyl-6-deoxytalosyl, is always linked to the allo-threonine in the acylpeptide. In addition the oligosaccharides from the glycopeptidolipids of each serovar are distinguished by their own individualistic sugars: 3-O-methylglucose in serovar 8; 2,3-di-O-methylfucose in serovar 9; 2-O-methylfucose in serovar 25; 4-O-methylrhamnose in the oligosaccharide from one of the two glycopeptidolipids in serovar 16 and apparently another rhamnosyl substituent in the other oligosaccharide. The glycopeptidolipid antigens in their structural principals, cellular location and physiological role bear a striking miniscular resemblance to cell wall components of other bacteria such as the O-antigenic and R-antigenic lipopolysaccharides. [ABSTRACT FROM AUTHOR]