Linda M. Beynon

Structural characteristics of the antigenic capsular polysaccharides and lipopolysaccharides involved in the serological classification of Actinobacillus (Haemophilus) pleuropneumoniae strains

Abstract The detailed structures of the specific capsular polysaccharides and cellular lipopolysaccharides of the 12 known serotypes of Actinobacillus (Haemophilus) pleuropneumoniae are presented and their serological relationships are discussed together with their significance in the control of swine pleuropneumonia.

The structure of the lipopolysaccharide O antigen from Yersinia ruckeri serotype 01

The O antigen obtained from the lipopolysaccharide of Yersinia ruckeri serotype 01, by mild acid hydrolysis, is composed of a branched tetrasaccharide repeating unit containing 2-acetamidino-2,6-dideoxy-L-galactose (L-FucAm), 2-acetamido-2-deoxy-D-glucose (D-GlcNAc), and 7-acetamido-3,5,7,9-tetradeoxy-5-(4-hydroxybutyramido)-D-glycero-L -galacto- nonulosonic acid (L-Sug). Partial hydrolysis of the O antigen with 0.1 M HClafforded a trisaccharide and a tetrasaccharide having nonulosonic acid at their reducing ends. Cleavage of the O antigen with anhydrous methanolic hydrogen fluoride afforded the methyl glycoside derivatives of a trisaccharide and a tetrasaccharide. 1H and 13C NMR analysis, including 1H-13C heteronuclear multiple bond correlation spectroscopy to locate the N-acyl substituents, together with mass spectrometric analysis of the above oligosaccharides, allowed the structure of the O-specific polysaccharide to be assigned as: [formula: see text].

Structure of the capsular polysaccharide from Actinobacillus pleuropneumoniae serotype 7

The structure of the capsular polysaccharide antigen of A. pleuropneumoniae serotype 7 was determined using 1D- and 2D-n.m.r. methods. Dephosphorylation, methylation, and g.l.c.-mass spectrometry methods were used to confirm the analysis. The type-7 specific polysaccharide was a high-molecular-weight teichoic acid-type polymer of D-galactose, glycerol, and phosphate (2:1:1), composed of glycosylglycerol repeating units joined through monophosphate diester linkages and with the structure: [formula: see text]

Characterization of a lipopolysaccharide O antigen containing two different trisaccharide repeating units from Burkholderia cepacia serotype E (O2)

The O antigen of the lipopolysaccharide of Burkholderia cepacia serotype E (O2) was shown by a combination of methylation analysis, partial hydrolysis, NMR, and mass spectrometric methods to be a high molecular weight polysaccharide composed of two different trisaccharide repeating units in the ratio 2:1. The major trisaccharide component is composed of two alpha-D-mannopyranosyl and one beta-D-galactopyranosyl residues with the structure, [-->2)-alpha-D-Man p-(1-->2)-alpha-D-Man p-(1-->4)-beta-D-Gal p-(1-->]n The minor trisaccharide component is a D-mannan composed of two alpha- and one beta-D-mannopyranosyl residues with the structure, [-->2)-alpha-D-Man p-(1-->2)-alpha-D-Man p-(1-->3)-beta-D-Man p-(1-->]n

Structure of the O-antigen of Actinobacillus pleuropneumoniae serotype 7 lipopolysaccharide

The structure of the O-antigen polysaccharide of A. pleuropneumoniae serotype 7 was investigated by methylation analysis, partial acid hydrolysis, periodate oxidation, and 1H- and 13C-n.m.r. spectroscopy. The polysaccharide repeating-unit consists of a branched tetrasaccharide having the following structure. [formula: see text]

Structural studies of the capsular polysaccharide from actinobacillus pleuropneumoniae serotype 12

The capsular polysaccharide of A. pleuropneumoniae is composed of 2-acetamido-2-deoxy-D-glucose (3 parts) and phosphate (1 part). The arrangement of these components in the repeating unit was determined by dephosphorylation, methylation, g.l.c.-m.x., and 1D and 2D n.m.r. spectroscopic methods. The polysaccharide was found to be a high molecular weight polymer of repeating trisaccharide units, joined through phosphate diester linkages, having the structure, (formula: see text).

Determination of the absolute configuration of the glycerol component in poly(glycosylglycerolphosphates) by GLC-MS

The identification of an increasing number of teichoic acid-like capsular polysaccharide structures containing glycerol phosphate linkages (see, for example, refs l-141, has necessitated the development of accurate and versatile methods for the determination of the absolute configuration of the chiral glycerol components. Only in a few instances has the assignment of the stereochemistry of 0-glycosyl glycerol, phosphorylated at one of the primary hydroxymethyl groups, within this type of polymer been reported 12-15 On the other hand, the stereochemistry of the . teichoic acids in the cell walls and membranes of gram-positive bacteria appears to be well established16,i7. Assignment of the stereochemistry of the glycerol residue in poly(glycosylglycerol phosphates) may be achieved by release of the chiral glycerol component, followed by its conversion to an appropriate derivative, and assignment of absolute stereochemistry by comparison with standards of known chirality by means of spectroscopic CORD, CD, or NMR), chromatographic or enzymic methods18,i9. In the case of polymers joined by + l)-glycerol-(3 + phosphodiester linkages, depolymerization can be accomplished with aqueous HF to afford a 1-0-glycosylated glycerol fragment. Configurational analysis is then possible by comparison of the chromatographic properties with standards of known absolute configuration2’ or by stereospecific enzymic assay following oxidation to the corresponding chiral glyceric acid . 21 More recen tl y a method based on the measurement of the chiroptical properties of 2,3-di-0-benzyl-sn-glycerol obtained from 1-0-glycosyl-sn-glycerols has been describedz2. When the teichoic acid contains 2-O-substituted glycerol phosphate linkages,