Somatic antigens of Pseudomonas aeruginosa. The structure of O-specific polysaccharide chains of lipopolysaccharides of P. aeruginosa O3 (Lányi), O25 (Wokatsch) and Fisher immunotypes 3 and 7

O-specific polysaccharides, obtained on mild acid degradation of lipopolysacchrides of the serologically related strains Pseudomonas aeruginosa O3 (Lányi classification), O25 (Wokatsch classification) and immunotypes 3 and 7 (Fisher classification), are built up of trisaccharide repeating units involving 2-acetamido-2,6-dideoxy-D-galactose (N-acetyl-D-fucosamine), 2,3-diacetamido-2,3-dideoxy-D-mannuronic acid or 2,3-diacetamido-2,3-dideoxy-L-guluronic acid and 3-acetamidino-2-acetamido-2,3-dideoxy-D-mannuronic acid or 3-acetamidino-2-acetamido-2,3-dideoxy-L-guluronic acid. Lányi O3(a),3d,3f and Wokatsch O25 polysaccharides contain also O-acetyl groups. On the basis of solvolysis with anhydrous hydrogen fluoride, resulting in trisaccharide fragments with N-acetylfucosamine residue at the reducing terminus, chemical modifications of the acetamidino group (alkaline hydrolysis to the acetamido group or reductive deamination to the ethylamino group), as well as analysis by 1H-NMR (including nuclear Overhauser effect experiments) and 13C-NMR spectroscopy, and fast-atom bombardment mass spectrometry, it was concluded that the repeating units of the polysaccharides have the following structures: (Formula: see text) where HexNAcAmA = alpha-L-GulNAcAmA (approximately 70%) or beta-D-ManNacAMA (approximately 30%). Lányi O3(a),3d,3f polysaccharide involves two types of repeating units, which differ from each other only in the configuration at C-5 of the 3-acetamidino-2-acetamido-2,3-dideoxyuronic acid residue. Lányi O3(a),3c,O3a,3d,3e and Fisher immunotypes 3 and 7 polysaccharides contain, together with the major repeating units shown above, a small proportion of units in which the derivative of alpha-L-guluronic acid is replaced by the corresponding beta-D-manno isomer. The data obtained provide the opportunity to substantiate the serological interrelations between these strains of P. aeruginosa by the presence in the O-specific polysaccharides of common monosaccharides or disaccharide fragments. The distinctions between them stem from the presence or absence of the O-acetyl group, a different configuration of the glycosidic linkage of the N-acetylfucosamine residue and/or a different configuration at C-5 of one or both derivatives of diaminouronic acids.     

The structure of O-specific polysaccharide of Pseudomonas aeruginosa immunotype 3; revision of the structure of acetoamidine derivative of 2,3-diamino-2,3-dideoxy-D-mannuronic acid

O-Specific side chain of P. aeruginosa immunotype 3 lipopolysaccharide is composed of N-acetyl-D-fucosamine (FucNAc), 2,3-diacetamido-2,3-dideoxy-L-guluronic acid (GulN2Ac2A) and 3-acetamidino = 2-acetamido = 2,3 = dideoxy = D-mannuronic acid (ManNAcAmA). The latter sugar is identified on the basis of solvolysis with anhydrous hydrogen fluoride, 13C NMR spectroscopy and fast-atom bombardment mass spectrometry analysis, as well as of reactions of acetamidino function (alkaline hydrolysis to acetamido group and reductive deamination to ethylamino group). Earlier, in the course of investigation of P. aeruginosa O3 lipopolysaccharides, the structure of 1-methyl-2-imidazoline was erroneously ascribed to the acetamidino group. The following structure was established for the repeating unit of immunotype 3 polysaccharide which is identical to P. aeruginosa O3(a),3c polysaccharide: ----4)-beta-D-ManNAcAmA-(1----4)-alpha-L-GulN2Ac2A-(1----3)- beta-D-FucNac-(1----.     

Identification of 3-acetamidino-2-acetamido-2,3-dideoxy-L-guluronic acid in lipopolysaccharide from Pseudomonas aeruginosa immunotype 7

O-Specific polysaccharide chain of Pseudomonas aeruginosa immunotype 7 lipopolysaccharide is composed of 3-acetamidino-2-acetamido-2,3-dideoxy-L-guluronic acid (GulNAcAmA), 2,3-diacetamido-2,3-dideoxy-D-mannuronic acid (ManN2Ac2A), and N-acetyl-D-fucosamine (FucNAc). On solvolysis with anhydrous hydrogen fluoride, the polysaccharide afforded a trisaccharide containing all its components. Borohydride reduction of the trisaccharide in boric acid solution resulted in conversion of reducing fucosamine into fucosaminitol, whereas in water the reduction was accompanied by reductive deamination of acetamidino function into ethylamino group. On hydrolysis with aqueous triethylamine, acetamidino group gave acetamido group. Analysis of the trisaccharides thus obtained by 1H NMR spectroscopy (including nuclear Overhauser effect), 13C NMR spectroscopy, and fast-atom bombardment mass spectrometry allowed the determination of the structure of the unusual uronic acid derivative and the following structure of the polysaccharide repeating unit: -4)-alpha-L-GulNAcAmA-(1-4)-beta-D-ManN2Ac2A-(1-3)-alpha-D-+ ++FucNAc-(1-.     

Somatic antigens of Pseudomonas aeruginosa. The structure of O-specific polysaccharide chains of P. aeruginosa O:3a, b and O:3a, d lipopolysaccharides

On mild acid degradation of Pseudomonas aeruginosa O:3a,b and O:3a,d lipopolysaccharides O-specific polysaccharides were isolated. Both polysaccharides were found to contain 2-acetamido-2,6-dideoxy-D-galactose, identified as fucosamine hydrochloride formed after hydrolysis with a very low yield. The other two components of the trisaccharide repeating unit, 2,3-diacetamido-2,3-dideoxy-D-mannuronic acid and 2,3-(1-acetyl-2-methyl-2-imidazolino-5,4)-2,3-dideoxy-D-mannuronic acid, were identified without isolation in their free state directly in the course of structural investigation of the polysaccharides. Both these monosaccharides have never before been found in nature. Solvolysis of either O:3a,b or O:3a,d polysaccharides with liquid hydrogen fluoride resulted in the formation of the same trisaccharide, N-acetylfucosamine residue being the reducing end. The structure of this trisaccharide, which is the repeating unit of both polysaccharides, was deduced from the results of successive chemical modifications and 13C-nuclear magnetic resonance spectra recorded for every oligosaccharide formed. As a result, the acidic diaminosugars were converted into 2,3-diacetamido-2,3-dideoxy-D-mannose indistinguishable from authentic sample. The O-specific polysaccharides O:3a,b and O:3a,d differed in the configuration of the glycosidic bond of N-acetylfucosamine residue only and had the following structures: leads to 4)DManImU(beta 1 leads to 4)DMan(NAc)2U (beta 1 leads to 3)DFucNAc(beta 1- leads to 4)DManImU(beta 1 leads to 4)DMan(NAc)2U (beta 1 leads to 3)DFucNAc(alpha 1- where DManImU = 2.3-(1-acetyl-2-methyl-2-imidazolino-5,4)-2, 3-dideoxy-D-mannuronic acid, DMan(NAc)2U = 2,3-diacetamido-2,3-dideoxy-D-mannuronic acid, DFucNAc = 2-acetamido-2,6-dideoxy-D-galactose. The structures established were in agreement with optical rotations and assignments of all the signals in the 13C-nuclear magnetic resonance spectra of the polysaccharides.     

Somatic antigens of Pseudomonas aeruginosa. The structure of O-specific polysaccharide chains of P. aeruginosa O10 (Lányi) lipopolysaccharides

Mild acid degradation of lipopolysaccharides from Pseudomonas aeruginosa O10a and O10a,b (Lányi classification) resulted in O-specific polysaccharides built up of trisaccharide repeating units containing 2-acetamido-2,6-dideoxy-D-glucose (N-acetylquinovosamine, DQuiNAc), 2-acetamido-2,6-dideoxy-D-galactose (N-acetylfucosamine, DFucNAc), and 5-acetamido-3,5,7,9-tetradeoxy-7-[(R)-3-hydroxybutyramido] -L-glycero-L-manno-nonulosonic acid. The latter is a di-N-acyl derivative of a new sialic-acid-like sugar which was called by us pseudaminic acid (PseN2). A 3-hydroxybutyric acid residue was also found in natural carbohydrates for the first time. In the O10a,b polysaccharide pseudaminic acid carried an O-acetyl group at position 4. For selective cleavage of the O10a polysaccharide, solvolysis with hydrogen fluoride was employed which, owing to the relatively high stability of the glycosidic linkage of pseudaminic acid, led to the disaccharide with this sugar on the non-reducing terminus. Performing the solvolysis in methanol afforded the methyl glycoside of this disaccharide which proved to be more advantageous for further analysis. Carboxyl-reduction made the glycosidic linkage of pseudaminic acid extremely labile, and mild acid hydrolysis of the carboxyl-reduced 010a polysaccharide afforded the trisaccharide with a ketose derivative on the reducing terminus. Establishing the structure of the oligosaccharide fragments obtained and interpreting the 13C nuclear resonance spectra of the polysaccharides allowed to determine the following structure for their repeating units: (formula: see text) In the polysaccharides the N-acetylquinovosamine residue is attached not to pseudaminic acid itself, but to its N-acyl substituent, 3-hydroxybutyryl group, and thus the monomers are linked via both glycosidic and amidic linkages.     

Somatic antigens of Pseudomonas aeruginosa. The structure of O-specific polysaccharide chains of the lipopolysaccharides from P. aeruginosa O5 (Lányi) and immunotype 6 (Fisher)

Lipopolysaccharides were isolated from dry bacterial cells of Pseudomonas aeruginosa O5a,b,c, O5a,b,d, O5a,d (Lányi classification) and immunotype 6 (Fisher classification) by the Westphal procedure. Their polysaccharide chains were built up of trisaccharide repeating units containing D-xylose, 2-acetamido-2,6-dideoxy-D-galactose and a new sialic acid-like sugar, the di-N-acyl derivative of 5,7-diamino-3,5,7,9-tetradeoxy-L-glycero-L-manno-nonulosonic (pseudaminic) acid. Formyl, acetyl and (R)-3-hydroxybutyryl groups were identified as the N-acyl substituents of the last monosaccharide; O5a,b,c and O5a,b,d lipopolysaccharides also contained O-acetyl groups. The glycosidic linkage of pseudaminic acid was extremely labile towards acids, and mild acid degradation of the lipopolysaccharides produced, instead of the O-specific polysaccharides, their trisaccharide fragments with pseudaminic acid at the reducing terminus. Similar degradation of immunotype 6 lipopolysaccharides, followed by oxidation with sodium metaperiodate, resulted in a disaccharide fragment due to destruction of xylose. In contrast the glycosidic linkage of pseudaminic acid proved to be more stable towards treatment with hydrogen fluoride than those of xylose and N-acetylfucosamine. As a result, solvolysis of immunotype 6 lipopolysaccharide with hydrogen fluoride in methanol gave methyl glycosides of a disaccharide and a trisaccharide with pseudaminic acid at the non-reducing terminus. Mild acid hydrolysis of these oligosides afforded free 5-N-acetyl-7-N-formylpseudaminic acid, which was identified by the 1H ande 13C nuclear magnetic resonance data, as well as by the mass spectrum of the corresponding fully methylated aldonic acid. As a result of the identification of all oligosaccharides obtained and comparative analysis of the 13C nuclear magnetic resonance spectra of the oligosaccharides and lipopolysaccharides the following structures were established for the repeating units of the polysaccharide chains of the lipopolysaccharides: (Formula: see text) where D-Xyl = D-xylose, D-FucNAc = 2-acetamido-2,6-dideoxy-D-galactose, Pse5N7NFm = 5-amino-3,5,7,9-tetradeoxy-7-formamido-L-glycero-L-manno-nonulosonic+ ++ acid (7-N-formylpseudaminic acid). All the polysaccharides have an identical carbohydrate skeleton and differ from each other by the acyl substituent at N-5 of pseudaminic acid [acetyl or (R)-3-hydroxybutyryl group] or by the presence or absence of the O-acetyl group at position 4 of N-acetylfucosamine. The data obtained account properly for the O specificity of the studied P. aeruginosa strains.     

Antigenic polysaccharides of bacteria. 17. The structure of O-specific polysaccharide chain of Pseudomonas aeruginosa X (Meitert) lipopolysaccharide

O-Specific polysaccharide composed of L-rhamnose and 2-acetamido-2-deoxy-D-mannose was obtained on mild acid degradation of P. aeruginosa X (Meitert classification) lipopolysaccharide. On the basis of non-destructive analis using 1H, 13C NMR spectroscopy and Klyne's rule calculation, as well as chemical methods (acid hydrolysis, methylation, Smith degradation), it was established that the polysaccharide is built up of disaccharide repeating units of the following structure: ----4)-alpha-L-Rha-(1----3)-beta-D-ManNAc-(1----.     

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 extracellular polysaccharide of Arthrobacter globiformis

An extracellular polysaccharide from Arthrobacter globiformis is composed of N-acetyl-D-glucosamine, N-acetyl-D-fucosamine, 2,3-diacetamido-2,3-dideoxy-D-mannuronic acid and O-acetyl groups in the ratio 1:1:2:1. On the basis of solvolysis with anhydrous hydrogen fluoride, which resulted in a tetrasaccharide fragment, and analysis by 1H and 13NMR spectroscopy, it was concluded that the polysaccharide has the following structure: (formula; see text).     

Somatic antigens of Pseudomonas aeruginosa. The structure of the O-specific polysaccharide chain of the lipopolysaccharide from P. aeruginosa O13 (Lányi)

The O-specific polysaccharide, obtained on mild acid degradation of lipopolysaccharide of Pseudomonas aeruginosa O13 (Lányi classification), is built up of trisaccharide repeating units involving 2-acetamidino-2,6-dideoxy-D-glucose (N-acetyl-D-quinovosamine, D-QuiNAc), 2-acetamidino-2,6-dideoxy-L-galactose (L-fucosacetamidine, L-FucAm), and a new sialic-acid-like sugar, 5,7-diacetamido-3,5,7,9-tetradeoxy-D-glycero-L-galacto-nonuloso n ic acid (Sug), and thus contains simultaneously both acidic and basic functions. Cleavage of the polysaccharide with hydrogen fluoride in methanol revealed the high stability of the glycosidic linkage of the ulosonic acid and afforded methyl glycosides of a disaccharide and a trisaccharide. The structures of the new ulosonic acid and acetamidino group were established by analysing the oligosaccharide fragments by 1H, 13C nuclear magnetic resonance spectrometry, as well as on the basis of their chemical conversions: alkaline hydrolysis of the acetamidino group into acetamido group, reductive deamination with lithium borohydride into the ethylamino group and acetylation with acetic anhydride in pyridine accompanied by intramolecular acylation of the acetamidino function by the ulosonic acid to form a six-membered lactam ring. Identification of the oligosaccharide fragments and comparative analysis of the 13C nuclear magnetic resonance spectra of the oligosaccharides and polysaccharide revealed the following structure of the repeating unit: ----3)D-QuiNAcp(alpha 1----3)Sugp(alpha 2----3)L-FucAmp(alpha 1----.     

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.     

Somatic antigens of Pseudomonas aeruginosa. The structure of O-specific polysaccharide chains of the lipopolysaccharides from P. aeruginosa O1 (Lányi), O3 (Habs), O13 and O14 (Wokatsch), and the serologically related strain NCTC 8505

Lipopolysaccharides from Pseudomonas aeruginosa O1 (Lányi classification), O3 (Habs classification), O13 and O14 (Wokatsch classification), and strain NCTC 8505, which is also related to serogroup O3 (Habs), have structurally similar O-specific polysaccharide chains built up of tetrasaccharide repeating units involving L-rhamnose (Rha), 2-acetamido-2-deoxy-D-glucose (GlcNAc), 2-acetamido-2-deoxy-L-galacturonic acid (GalNAcA), and a di-N-acyl derivative of bacillosamine (BacN): 2,4-diacetamido-2,4,6-trideoxy-D-glucose or 2-acetamido-2,4,6-trideoxy-4-[(S)-3-hydroxybutyramido]-D-glucose. The latter derivative was obtained free by solvolysis with hydrogen fluoride of carboxyl-reduced Habs O3 polysaccharide, and was identified by 1H-nuclear magnetic resonance spectroscopy and by mass spectrometry of the corresponding methylated alditol. Habs O3, Lányi O1, and Wokatsch O14 polysaccharides contained O-acetyl groups. Solvolysis with hydrogen fluoride of the native Habs O3 polysaccharide resulted in selective cleavage of the glycosidic linkages of 6-deoxy sugars to give the trisaccharide fragment involving all three N-acylated amino sugars. Similar solvolysis of NCTC 8505 polysaccharide afforded a mixture of disaccharide and trisaccharide with N,N'-diacetylbacillosamine at the reducing end. Smith degradation of Habs O3 polysaccharide resulted in selective oxidation of rhamnose to give a glycoside of a trisaccharide with glyceraldehyde as the aglycone. Smith degradation of NCTC 8505 polysaccharide was complicated by the formation of the glycoside of a trisaccharide with an aglycone of unknown structure. A trisaccharide with rhamnose at the reducing end was also isolated after Smith degradation of the latter polysaccharide. Analysis of the composition and structure of all oligosaccharides obtained, and detailed examination of the 13C-nuclear magnetic resonance spectra of these oligosaccharides, and of both intact and modified polysaccharides, revealed the following structures of the repeating units. The structure for the NCTC 8505 polysaccharide differs from that proposed previously [Tahara, Y. and Wilkinson, S.G. (1983) Eur. J. Biochem. 134, 299-304] in the configurations assigned to the glycosidic linkages of rhamnose and bacillosamine. The results obtained show the P. aeruginosa strains studied to represent three different O-serotypes in a single O-serogroup (Formula: see text).     

Antigenic polysaccharides of bacteria. 18. Structure of O-specific polysaccharide chains of Pseudomonas aeruginosa 05 (Lányi) lipopolysaccharide

Polysaccharide chains of P. aeruginosa O5a, b, c, O5a, b, d and O5a, d (Lányi classification) lipopolysaccharides contain D-xylose, N-acetyl-D-fucosamine (FucNAc) and a derivative of 5,7-diamino-3,5,7,9-tetradeoxy-L-glycero-L-manno-nonulosonic acid (pseudaminic acid, PseN2) carrying acetyl or (R)-3-hydroxybutyryl (Hb) and formyl (Fm) groups as N-acyl substituents. Degradation of the lipopolysaccharides with dilute acetic acid caused depolymerisation of the polysaccharide chains as a result of cleavage of glycosidic linkage of pseudaminic acid to give trisaccharides representing chemical repeating units of the polysaccharides. Basing on analysis of the trisaccharides using 1H and 13C NMR spectroscopy and mass-spectrometry, the following structures of the polysaccharide chains were established: (Formula: see text). O5a, d polysaccharide is identical to P. aeruginosa immunotype 6 O-specific polysaccharide.     

Antigenic bacterial polysaccharides. 14. Structure of the O-specific polysaccharide chain of a lipopolysaccharide from Pseudomonas aeruginosa (Lányi)

The lipopolysaccharide from Pseudomonas aeruginosa O12 (Lányi classification) gave on mild acid hydrolysis an O-specific polysaccharide built of D-ribose and N-acetyl-D-galactosamine. The disaccharide structure----4)-alpha-GalNAcp-(1----2)-beta-Ribf-(1----for the repeating unit of the polysaccharide was established by nondestructive way involving full interpretation of its 1H- and 13C-NMR-spectra, using homonuclear and selective heteronuclear 13C[1H] double resonances.     

Somatic antigens of Pseudomonas aeruginosa. The structure of the O-specific polysaccharide chains of lipopolysaccharides of P. aeruginosa serogroup O4 (Lányi) and related serotype O6 (Habs) and immunotype 1 (Fisher)

Acidic O-specific polysaccharides were isolated on mild acidic degradation of lipopolysaccharides of Pseudomonas aeruginosa serotypes O4a,b, O4a,c, O4a,d (Lányi classification) and serologically related to them serotype O6 (Habs classification) and immunotype 1 (Fisher classification). The polysaccharides had identical monosaccharide composition and were built up of L-rhamnose, 2-acetamido-2,6-dideoxy-D-glucose,2-formamido-2-deoxy-D-galacturonic acid and 2-acetamido-2-deoxy-D-galactouronamide residues. The latter two derivatives of D-galactosaminuronic acid were found in nature for the first time. All the polysaccharides, but Lányi serotype O4a,c, contained O-acetyl groups. The polysaccharides were readily de-O-acetylated with aqueous triethylamine and de-N-formylated with dilute hydrochloric acid. De-N-formylated polysaccharide of serotype O4a,c was selectively cleaved with nitrous acid upon 2-amino-2-deoxygalacturonic acid residues to form a tetrasaccharide with a 2,5-anhydrotaluronic acid residue on the reducing end. The tetrasaccharide represented a modified repeating unit of the polysaccharide. Solvolysis of all intact polysaccharides with hydrogen fluoride selectively split the glycosidic linkages of 6-deoxy sugars to give the same trisaccharide, including both derivatives of galactosaminuronic acid and having 2-acetamido-2,6-dideoxyglucose on the reducing end. Structural investigation of the oligosaccharides obtained together with methylation analysis and 13C nuclear magnetic resonance data revealed the following structures of the O-specific polysaccharides: (Formula: see text) An independent confirmation of the structures of the repeating units was obtained as the result of full interpretation of the 13C nuclear magnetic resonance spectra of the intact and modified polymers. Spectral data analysis revealed a number of regularities in the effects of glycosidation connecting their values with the anomeric and absolute configuration of pyranose residues. The data on the structures of the O-specific polysaccharides indicated that each of the five P. aeruginosa strains under study should be considered as an individual O-serotype within one O-serogroup.     

Structural analysis of the exopolysaccharide from Burkholderia caribensis strain MWAP71

Burkholderia caribensis strain MWAP71 was isolated from rhizosphere soil microaggregates in Martinique. The extracellular polysaccharide produced by this strain was found to be composed of D-glucose (D-Glc), 6-deoxy-L-talose (L-6dTal), 3-deoxy-D-manno-oct-2-ulosonic acid (Kdo), and an O-acetyl group in a molar ratio of 2:1:1:1. The primary structure of the polysaccharide was shown by sugar analysis, electrospray mass spectrometry, partial acid hydrolysis and 1-D and 2-D NMR spectroscopy to consist of a tetrasaccharide repeating unit having the following structure: [structure in text].     

O-antigen conversion in Pseudomonas aeruginosa PAO1 by bacteriophage D3.

The lysogenization of Pseudomonas aeruginosa PAO by phage D3 results in derivatives which are resistant to superinfection by phage D3c by virtue of the fact that homologous phage cannot adsorb to these cells. The serologically and morphologically unrelated phage E79 showed a markedly decreased adsorption rate to the lysogen PAO(D3). Since both of these phages are lipopolysaccharide specific, these results suggested lysogenic conversion of the phage receptor. The lipopolysaccharide was extracted from strain PAO by the hot phenol-water technique, but this procedure was ineffective with PAO(D3). We developed a technique involving cold trichloroacetic acid extraction, followed by ultracentrifugation, digestion of the high-speed pellet with proteinase K, and ultimate purification on CsCl step gradients. The lipopolysaccharide from the wild type had inactivating activity against D3 and E79, whereas that from PAO(D3) inactivated neither. Chromatographic analysis indicated that the convertant lipopolysaccharide was smooth, and quantitative chemical analyses of the two preparations showed no differences in the level of the major fatty acids, amino compounds, or neutral sugars. On the other hand, sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the side chains had a decreased migration rate through the gel matrix. The application of 1H and 13C nuclear magnetic resonance spectroscopic analysis revealed that the PAO side chain is chemically identical to that of serotype O:2a,d, containing 2,3-(1-acetyl-2-methyl-2-imidazolino-5,4)-2,3-dideoxy-D-mannuronic acid, 2,3-diacetamido-2,3-dideoxy-D-mannuronic acid, and 2-acetamido-2,6-dideoxy-D-galactose (D-fucosamine). The molecular basis of the conversion event was (i) the introduction of an acetyl group into position 4 of the fucosamine residue and a change in the bonding between trisaccharide repeating units from alpha 1 leads to 4 to beta 1 leads to 4.     

Antigenic polysaccharides of bacteria. 35. Establishment of the structure of polysaccharide chains of lipopolysaccharides of Pseudomonas cepacia IMV 4176 and IMV 4202 (Serotype 3)

On mild acid degradation of the Pseudomonas cepacia strain IMV 4176 lipopolysaccharide, two polysaccharides were obtained, one of which is a homopolymer of N-acetyl-D-galactosamine and the other is composed of equal amounts of N-acetyl-D-galactosamine and D-ribose. Partial hydrolysis with aqueous oxalic acid caused depolymerization of the heteropolysaccharide, and the homopolysaccharide was isolated in the individual state. On the basis of methylation and 13C NMR analysis, it was concluded that both polysaccharides are built up of disaccharide repeating units having the following structures: ----4)-alpha-D-GalpNAc-(1----4)-beta-D-GalpNAc-(1---- and ----4)-alpha-D-GalpNAc-(1----2)-beta-D-Ribf-(1----. The heteropolysaccharide from P. cepacia strain 4176 is identical by the structure of the repeating unit to the O-specific polysaccharide of P. cepacia strain IMV 4202 (serotype 3), Pseudomonas aeruginosa O12 and Serratia marcescens O14.     

Structural analysis of the O-antigen polysaccharide from the Shiga toxin-producing Escherichia coli O172.

The structure of the O-antigen polysaccharide from Escherichia coli O172 has been determined. In combination with sugar analysis, NMR spectroscopy shows that the polysaccharide is composed of pentasaccharide repeating units. Sequential information was obtained by mass spectrometry and two-dimensional NMR techniques. An O-acetyl group was present as 0.7 equivalent per repeating unit. Treatment of the O-deacetylated polysaccharide with aqueous 48% hydrofluoric acid rendered cleavage of the phosphodiester in the backbone of the polymer and the pentasaccharide isolated after gel permeation chromatography was structurally characterized. Subsequent NMR experiments on polymeric materials revealed the structure of the repeating unit of the O-polysaccharide from E. coli O172 as:-->P-4)-alpha-D-Glcp-(1-->3)-alpha-L-FucpNAc-(1-->3)-alpha-D- GlcpNAc-(1-->3)-alpha-L-FucpNAc-(1-->4)-alpha-D-Glcp6Ac-(1-->     

Structure of the K95 antigen from Escherichia coli O75:K95:H5, a capsular polysaccharide containing furanosidic KDO-residues

The structure of the K95 antigenic capsular polysaccharide (K95 antigen) of Escherichia coli O75:K95:H5 was elucidated by determination of the composition, 1H- and 13C-n.m.r. spectroscopy, periodate oxidation, and methylation analysis. The K95 polysaccharide, which contains furanosidic 3-deoxy-D-manno-2-octulosonic acid (KDOf) residues, consists of----3)-beta-D-Rib-(1----8)-KDOf-(2----repeating units, has a molecular weight of approximately 25,000 (approximately 65 repeating units), and is randomly O-acetylated (1 acetyl group per repeating unit at unknown positions).