Antigenic bacterial polysaccharides. 24. The structure of the O-specific polysaccharide chain of Salmonella arizonae 063 (Arizona 08) lipopolysaccharide

The O-specific polysaccharide chain of the Salmonella arizonae O63 lipopolysaccharide is composed of D-glucose, D-galactose, N-acetyl-D-galactosamine, and 3-acetamido-3,6-dideoxy-D-galactose (Fuc3NAc) residues in the ratio 1:1:2:1. On the basis of methylation analysis and calculations of 13C-NMR-spectra of the polysaccharide and of the product of its selective cleavage with anhydrous hydrogen fluoride, the linear polymer lacking 3-acetamido-3,6-dideoxygalactose, it was concluded that the polysaccharide has the following structure: (Formula: see text).     

The structure of O-specific polysaccharide chains of lipopolysaccharides from Citrobacter 032 and Salmonella arizonae 064 (Arizona 29)

On the basis of acid hydrolysis, methylation, Smith degradation, selective cleavage with anhydrous hydrogen fluoride, and 13C NMR analysis, the repeating unit of the O-specific polysaccharide of Citrobacter O32 was concluded to have the following structure: (Formula: see text). The repeating unit of the Salmonella arizonae O64 O-specific polysaccharide has the same structure lacking the O-acetyl group.     

The structure of the O-specific polysaccharide from Salmonella cerro (serogroup K, O:6,14,18)

The following structure of the Salmonella cerro LPS O-chain repeating unit has been determined using NMR and chemical methods: -->4)-alpha-D-Man(1-->2)-alpha-D-Man(1-->2)-beta-D-Man(1-->3)-alpha-D-GalNAc-(1-->.     

Antigenic bacterial polysaccharides. 23. The structure of the O-specific polysaccharide chain of Salmonella arizonae 059 lipopolysaccharide

The O-specific polysaccharide of Salmonella arizonae O59 (Arizona 19) is composed of D-galactose, N-acetyl-D-glucosamine, and N-acetyl-L-fucosamine (FucNAc, 2-acetamido-2,6-dideoxy-L-galactose) in the ratio 1:1:1. The computerized calculation of the 13C NMR spectrum of the polysaccharide, based on the monosaccharide composition, spectra of the free monosaccharides and glycosydation effects, together with the chemical analysis (methylation and Smith degradation) showed that the polysaccharide is built up of trisaccharide repeating units of the following structure: ----3)-alpha-L-FucNAcp(1----3)-beta-D-GlcNAcp-(1----2)-beta- D-Galp-1(----. The molecular basis of serological interrelations between S. arizonae O59 and Pseudomonas aeruginosa O7 (Lányi) is discussed.     

13C-NMR spectrum of O-specific polysaccharide from the lipopolysaccharide of Yersinia pseudotuberculosis of serotype III

A 13C NMR spectrum of O-specific polysaccharide isolated from Yersinia pseudotuberculosis III serovar lipopolysaccharide has been interpreted. This allowed to define more precisely the configuration of glycosidic bonds and to confirm the structure of the repeating unit of the specific polysaccharide which was earlier established by other methods.     

Computer analysis of polysaccharides with linear repetitive link from 13C-NMR data

The possibility of computerised analysis of primary structures of polysaccharides on the basis of 13C NMR data and average values of alpha- and beta-effects of glycosidation was evaluated. Theoretical 13C NMR spectra for all possible structures of some linear polysaccharides were calculated by using additive scheme of glycosidation effects. In each case it was found that the structure characterised by the least sum of squared deviations of chemical shifts for the signals in the calculated and experimental spectra corresponds to the sequence and modes of linkages between monosaccharide residues in polysaccharides determined by an independent way.     

Study of the structure of O-specific polysaccharide of Salmonella anatum using 1H- and 13C-NMR-spectroscopy

The Salmonella anatum O-specific polysaccharide structure was fully confirmed by means of complete interpretation of its 13C NMR spectrum, using the selective double resonances and NOE experiments: [-3(6Ac)GaIp alpha 1-6Manp beta 1-4Rhap alpha 1-]n.     

Structure of the sialic acid-containing O-specific polysaccharide from Salmonella enterica serovar Toucra O48 lipopolysaccharide.

Lipopolysaccharide was extracted from cells of Salmonella enterica serovar Toucra O48 and, after mild acid hydrolysis (1% AcOH, 1 h, 100 degrees C or 0.1 M NaOH-AcOH, pH 4.5, 5 h, 100 degrees C), the O-specific polysaccharide was isolated and characterized. The core and an oligosaccharide containing a fragment of the repeating unit linked to the core region were also obtained, depending on hydrolysis conditions. On the basis of sugar and methylation analyses and NMR spectroscopy of the hydrolysis products, the biological repeating unit of the O-specific polysaccharide was shown to be the following trisaccharide: -->4)-alpha-Neup5Ac(2-->3)-L-alpha-FucpNAc(1-->3)-D-beta-Glc pNAc(1--> The polysaccharide O-chain was substituted with a single molar equivalent of O-acetyl group, distributed between the Neu5Ac O-9 and O-7 positions, in an approximate ratio of 7 : 3.     

The structure of O-specific polysaccharide from Yersinia enterocolitica serotype O:6.31 lipopolysaccharide

The serologically active O-specific polysaccharide has been isolated from the lipopolysaccharide of Yersinia enterocolitica, serovar O: 6.31. Using methylation, partial acid hydrolysis and 13C NMR spectroscopy, the main structural moiety of the O-specific polysaccharide is shown to be the following disaccharide repeating unit: (Formula: see text).     

The structure of the O-specific polysaccharide from Ralstonia pickettii

The following structure of the Ralstonia pickettii have been determined using NMR and chemical methods: -->4)-alpha-D-Rha-(1-->4)-alpha-L-GalNAcA-(1-->3)-beta-D-BacNAc-(1-->.     

The structure of Proteus mirabilis O3 O-specific polysaccharide containing N-(2-hydroxyethyl)-D-alanine

O-Specific polysaccharide was obtained by mild acid degradation of Proteus mirabilis O3 lipopolysaccharide. The polysaccharide was dephosphorylated with 48% HF to give a linear polysaccharide and an amino acid, N-(2-hydroxyethyl)-D-alanine. The structure of the polysaccharide was determined by methylation, Smith degradation and computer-assisted analysis of the 13C-NMR spectra of original and dephosphorylated polymers and oligomers. The structure of the amino acid was investigated by using 1H and 13C-NMR spectroscopy and mass spectrometry (applied to the acetylated methyl ester derivative). Its absolute configuration was established by comparison of the optical rotation value and CD spectrum of the natural and synthetic product. On the basis of the data obtained, it was concluded that the repeating unit of P. mirabilis O3 O-specific polysaccharide has the following structure: (formula; see text) Removal of the amino acid phosphate substituent significantly decreased serological activity of the O-specific polysaccharide, thus showing the immunodominant role of this group. Serological cross-reactions between P. mirabilis O3 and O27 were demonstrated and tentatively substantiated.     

Structural analysis of the O-specific polysaccharide isolated from Plesiomonas shigelloides O51 lipopolysaccharide

Plesiomonasshigelloides strain CNCTC 110/92 (O51) was identified as a new example of plesiomonads synthesising lipopolysaccharides (LPSs) that show preference for a non-aqueous surrounding during phenol/water extraction. Chemical analyses combined with ¹H and ¹³C NMR spectroscopy, MALDI-TOF and ESI mass spectrometry showed that the repeating units of the O-specific polysaccharides isolated from phenol and water phase LPSs of P. shigelloides O51 have the same structure: →4)-β-d-GlcpNAc3NRA-(1→4)-α-l-FucpAm3OAc-(1→3)-α-d-QuipNAc-(1→, containing the rare sugar constituent 2,3-diamino-2,3-dideoxyglucuronic acid (GlcpNAc3NRA), and substituents such as d-3-hydroxybutyric acid (R) and acetamidino group (Am). The HR-MAS NMR spectra obtained for the isolated LPSs and directly on bacteria indicated that the O-acetylation pattern was consistent throughout the entire preparation. The ¹H chemical shift values of the structure reporter groups identified in the isolated O-antigens matched those present in bacteria. We have found that the O-antigens recovered from the phenol phase showed a higher degree of polymerisation than those isolated from the water phase.     

The use of 13C-NMR spectra of lipopolysaccharide-protein complexes to determine the structure of O-specific polysaccharides

Lipopolysaccharide-protein complexes are shown to be useful for elucidation of O-specific polysaccharide structures. This approach may be especially useful in studying polysaccharides with labile linkages in the molecule.     

The structure of the glycerophosphate-containing O-specific polysaccharide from Escherichia coli 0130

A phosphorylated O-specific polysaccharide was obtained by mild acidic degradation of the lipopolysaccharide from the intestinal bacterium Escherichia coli 0130 and characterized by the methods of chemical analysis, including dephosphorylation, and 1H and 13C NMR spectroscopy. The polysaccharide was shown to be composed of branched tetrasaccharide repeating units containing two N-acetyl-D-galactosamine residues, D-galactose, D-glucose, and glycerophosphate residues (one of each). The polysaccharide has the following structure, which is unique among the known bacterial polysaccharides.     

Structure of the O-specific polysaccharide from the lipopolysaccharide of Serratia marcescens O8

Structural studies have been carried out on the O-specific polysaccharide from the lipopolysaccharide of the reference strain (CDC 1604-55) for serogroup O8 of Serratia marcescens. The polymer has a branched, tetrasaccharide repeating unit of D-galactose(Gal),D-glucose(Glc), and 2-acetamido-2-deoxy-D-glucose(GlcNAc) with the following structure: (Formula: see text). The anomeric configuration assigned to the glucose residue differs from that (beta) previously proposed [Tarcsay, L., Wang, C. S., Li, S.-C. and Alaupovic, P. (1973) Biochemistry 12, 1948-1955]. The structure of the O8 polymer is identical with that of one of two polymers present in the cell envelope of a strain (CDC 1783-57) of S. marcescens O14.     

The O-specific polysaccharide structure from the lipopolysaccharide of the Gram-negative bacterium Raoultella terrigena

The structure of the repeating unit of the O-specific polysaccharide from the lipopolysaccharide of the enterobacterium Raoultella terrigena was determined by means of chemical and spectroscopical methods and was found to be a linear tetrasaccharide containing a cyclic acetal of pyruvic acid (Pyr) as depicted below.[Carbohydrate structure: see text].     

The genetics and structure of the O-specific polysaccharide of Yersinia pseudotuberculosis serotype O:10 and its relationship with Escherichia coli O111 and Salmonella enterica O35

The O-specific polysaccharide (OPS) is a variable constituent of the lipopolysaccharide of Gram-negative bacteria. The polymorphic nature of OPSs within a species is usually first defined serologically, and the current serotyping scheme for Yersinia pseudotuberculosis consists of 21 O serotypes of which 15 have been characterized genetically and structurally. Here, we present the structure and DNA sequence of Y. pseudotuberculosis O:10 OPS. The O unit consists of one residue each of d-galactopyranose, N-acetyl-d-galactosamine (2-amino-2-deoxy-d-galactopyranose) and d-glucopyranose in the backbone, with two colitose (3,6-dideoxy-l-xylo-hexopyranose) side-branch residues. This structure is very similar to that shared by Escherichia coli O111 and Salmonella enterica O35. The gene cluster sequences of these serotypes, however, have only low levels of similarity to that of Y. pseudotuberculosis O:10, although there is significant conservation of gene order. Within Y. pseudotuberculosis, the O10 structure is most closely related to the O:6 and O:7 structures.     

Structural determination of the O-specific polysaccharide from Aeromonas hydrophila strain A19 (serogroup O:14) with S-layer

Bacteria belonging to the genus Aeromonas are Gram-negative mesophilic and essentially ubiquitous in the microbial biosphere; moreover they are considered very important pathogens in fish and responsible for a great variety of human infections.The virulence of Gram-negative bacteria is often associated with the structure of lipopolysaccharides, which consist of three regions covalently linked: the glycolipid (lipid A), the oligosaccharide region (core region) and the O-specific polysaccharide (O-chain, O-antigen).The O-chain region seems to play an important role in host-pathogen interaction. In the case of Aeromonas hydrophila the majority of pathogenic strains belongs to serogroups O:11, O:16, O:18 and O:34. In this paper, we report the complete structure of the O-chain of A. hydrophila strain A19 (serogroup O:14), a pathogenic strain isolated from European eels, which showed high virulence when tested in trout or mice. Dried cells were extracted by the PCP (phenol/chloroform/petroleum ether) method obtaining the lipopolysaccharide. After mild acid hydrolysis the lipid A was removed by centrifugation and the obtained polysaccharide was fully characterized by means of chemical analysis and one- and two-dimensional NMR spectroscopy. All the data collected are directed towards the following structure: