PubMed Health⌕ Search

Biomedical subjects

A S Shashkov

Publications and source records attributed to A S Shashkov.

At least 199 records · Page 11Linked to original sources
PubMed1993

Structure of the O-specific polysaccharide of Salmonella arizonae O45.

The O-specific polysaccharide of Salmonella arizonae O45 (Arizona 11) is acidic and has a branched hexasaccharide repeating unit containing two residues of L-fucose, one residue each of D-galactose, D-ribose, D-glucuronic acid, and 2-acetamido-2-deoxy-D-glucose, and an O-acetyl group. It was studied with the help of 1H and 13C NMR spectroscopy, including 1D selective spin-decoupling and homonuclear Hartmann-Hahn spectroscopy, 2D homonuclear and 13C-1H heteronuclear shift-correlated (COSY) and NOE (ROESY) spectroscopy, as well as by methylation analysis, and selective cleavages with anhydrous HF (or dilute HCl) and lithium in ethylenediamine to yield two different tetrasaccharide fragments. As a result, the following structure of the polysaccharide was established: [formula: see text] Anomalous 13C chemical shifts were observed in the spectrum of the trisaccharide fragment alpha-L-Fucp-(1-->2)-beta-D-Gal p-(1-->3)-beta-D-Glc pNAc, structurally related to the Le(d) blood-group determinant, and rationalised by inter-residue proton-proton interactions.

Acetylglucosamine↗
PubMed1993

Structure of the O56 antigen of Escherichia coli, a polysaccharide containing 7-substituted alpha-N-acetylneuraminic acid.

The O56 polysaccharide moiety of the O56 antigen (LPS) consists of D-glucose, D-galactose, 2-acetamido-2-deoxy-D-glucose, and N-acetylneuraminic acid in the molar ratios 1:1:1:1. Methylation analysis, periodate oxidation, mild acid hydrolysis, as well as 1H and 13C NMR spectroscopy showed that the O56 polysaccharide has the primary structure [formula: see text]

Carbohydrate Conformation↗
PubMed1993

A new structural type of teichoic acid and some chemotaxonomic criteria of two species Nocardiopsis dassonvillei and Nocardiopsis antarcticus.

The cell-wall teichoic acids of Nocardiopsis dassonvillei IMRU 509T, IMRU 504 and IMRU 1250 and Nocardiopsis antarcticus VKM Ac-836T have the same unique structure that has not heretofore been found in bacteria. The polymer is built of 10 to 13 repeating units: -1snGro3-P-3-beta-D-GalNAc1-2snGro3-P-. The structure has been established by chemical analysis and with NMR spectroscopy. A study of the cell-wall monosaccharide composition, peptidoglycan, and cell phospholipids also provides evidence for the close similarity of these two species.

Actinomycetales↗
PubMed1993

[Computerized structural analysis of O-specific polysaccharides O1A, O1B, and O1C from Escherichia coli].

A computer evaluation of 13C-NMR data for the title polysaccharides based on the monosaccharide and methylation analysis data led to the structure of the repeating unit of the O1A polysaccharide as well as to several probable structures of the O1C polysaccharide, of which the correct one was inferred by means of a single NOE experiment. The analysis of the spectrum of the O1B polysaccharide was unsuccessful, due to the presence in its structure of the fragment alpha-L-Rha-(1-->2)-alpha-D-Gal-(1-->3)-D-GlcNAc with the terminal (1-->2)-linkage, whose spectral data could not be calculated by additive schemes using only glycosylation effects. However in reevaluation of the O1B spectral data by taking into account the deviations from additivities of the chemical shifts values in spectra of the related trisaccharides, to reveal the most probable structure of the O1B's repeating unit. [formula: see text]

Carbohydrate Conformation↗
PubMed1993

[Antigenic polysaccharides of bacteria 38. Structure of O-antigens of Pseudomonas solanacearum ICMP 7942 and ICMP 8169].

The structures I and II were established for the O-antigens of Pseudomonas solanacearum ICMP 7942 and ICMP 8169, respectively, by means of NMR-spectroscopy, including 2D homonuclear shift-correlated spectroscopy (COSY), rotating-frame NOE spectroscopy (ROESY) and heteronuclear 13C, 1H multiquantum correlation spectroscopy (HMQC). In the polysaccharide of the ICMP 8169 strain substitution of the main chain by the xylose residue is non-stoichiometric, i.e. this antigen contains also the repeating units of the polysaccharide of the ICMP 7942 strain (the ratio II: I is approximately 3:1). [formula: see text]

Carbohydrate Sequence↗
PubMed1993

[Immunochemical studies of O-specific polysaccharide from Proteus penneri 14 lipopolysaccharide].

O-specific polysaccharide was obtained on mild acid degradation of Proteus penneri strain 14 lipopolysaccharide and found to contain equimolar of D-galactose, D-ribose, 2-acetamido-2-deoxy-D-glucose, N-(D-galacturonoyl)-L-alanine and 3-(Nacety-L-alanyl)-amido-3,6-dideoxy-D-glucose. On the basis of non-destructive NMR analysis it was concluded that repeat unit of the 0-specific polysaccharide of P. penneri 14 has the following structure: -2-beta-D- Quip3NAlaAc-(1-->4)-alfa-D-GalpAAla-(1-->2)-beta-D- Ribf-(1-->4)-beta-D-Galp-(1-->3)-beta-D--GlcpNAc-(1--> This structure was confirmed by structural elucidation of trisaccharide and disaccharide fragments prepared on mild acid hydrolysis of the polysaccharide. Immunodominant role of the partial structures of the pentasaccharide repeating unit in manifesting serological specificity of P. penneri 14 was discussed. Very weak cross-reactions of P. penneri anti-serum were observed with E. coli 0114 and Shigella boydii 08 LPS's, which showed some structural similarities. No cross-reaction with P. mirabilis 027 LPs was detected.

Antigens, Bacterial↗
PubMed1993

[Immunochemical studies of O-specific polysaccharide of Proteus penneri 42 lipopolysaccharide].

O-specific polysaccharide was obtained an mild acid degradation of Proteus penneri strain 42 lipopolysaccharide and found to contain D-glucose, D-galacturonic acid and 2-acetamido-2-deoxy-D-glucose in molar ratio 2:1:1. Methylation analysis showed that the polysaccharide is linear, one of the glucose residue is substituted at position 2, the second one and the residue of galacturonic acid at position 4, and the 2-acetamido-2-deoxy-D-glucose residue at position 3. On the basis of non-destructive NMR analysis the following structure of repeat unit of the O-specific polysaccharide was established and confirmed independently by methylation analysis: -2)-beta-D-Glc-(1-->4)-beta-D-Glc-(1-->3)-beta-D-GlcNAc-(1-->4)-al fa-D-GalA-(1--> The serological investigation with application of P. penneri strain 42 anti O-serum has shown the activity of homologous preparations of LPS and PS, as well as cross-reactions with heterologous lipopolysaccharides from other Proteus strains.

Immunochemistry↗
PubMed1993

[Structure of the repeating unit of acid polysaccharide from Alteromonas sp. 4MS17].

An acidic polysaccharide from Alteromonas sp. 4MC17 is built up of trisaccharide repeating units containing D-glucose, D-mannose and D-galacturonic acid residues. On the basis of methylation studies, 1H and 13C NMR-spectroscopy data, including two-dimensional homonuclear correlation spectroscopy and nuclear Overhauser effects, the following structure was suggested for the polysaccharide repeating unit: -->4)-beta-D-Glcp-(1-->4)-beta-D-GalpA-(1-->4)-beta-D-Manp-( 1-->.

Carbohydrate Conformation↗
PubMed1993

[Structure of the repeating unit of acid polysaccharide from Alteromonas macleodii 2MM6].

An acidic polysaccharide from Alteromonas macleodii 2MM6 is shown to consist of tetrasaccharide repeating units containing D-galactose, 3-O-acetyl-2-acetamido-2-deoxy-D-glucose, 2-acetamido-2-deoxy-L-guluronic acid and 3,6-dideoxy-3-(4-hydroxybutyramido)-D-galactose residues. On the basis of sugar analysis, 1H and 13C NMR-spectroscopy data including NOE and one-dimensional HOHAHA experiments, the following structure was suggested for the polysaccharide repeating unit: [formula: see text] R: -CO-CH2-CH2-CH2-OH.

Carbohydrate Conformation↗
PubMed1993

[Phosphorus-containing polysaccharides from the cell wall of Actinoplanes sp. INA 3697 cell wall].

A phosphorus-containing polysaccharide has been isolated from defatted cells of Actinoplanes sp. INA 3697. The structure of the polymer has been established by a non-destructive method including one- and two-dimensional NMR 1H-spectroscopy as well as by NMR 13C-spectroscopy and confirmed by chemical analysis of the monosaccharide composition and the repeating link. Association of the repeating units-2-acetamido-2-deoxy-beta-D-mannopyranosyl-(1-->3)-2-acetamido -2-deoxy-D-glucopyranoses, is provided by phosphodiester bonds between C1 of N-acetylglucosamine and C6 of N-acetylmannosamine. The polymer molecule is made up of about 12 disaccharides and is localized in the cell wall of the actinomycete. No structurally identical phosphorylated polysaccharides have as yet been found in prokaryotes.

Actinomycetales↗
PubMed1993

[Structure of the repeating link of the acid polysaccharide of Alteromonas haloplanktis KMM 156].

An acidic capsular and an O-specific polysaccharide were isolated from the marine microorganism Alteromonas haloplanktis KMM 156. Both polysaccharides have the identical structure and are built up of tetrasaccharide repeating units, containing two residues of L-rhamnose as well as a 2-acetamido-2-deoxy-D-glucose and a 3-O-[(R)-1-carboxyethyl]-D-glucose (Glc3Lac) residue. On the basis of methylation studies, 1H- and 13C-NMR-spectroscopy including nuclear Overhauser effect and two-dimensional heteronuclear 13C/1H correlation spectroscopy, the following structure was suggested for the polysaccharide repeating unit: [formula: see text]

Carbohydrate Sequence↗
PubMed1992

Computer-assisted analysis of the structure of regular branched polysaccharides containing 2,3-disubstituted rhamnopyranose and mannopyranose residues on the basis of 13C NMR data.

A computer-assisted approach to the analysis of the structure of branched polysaccharides that contain 2,3-di-O-glycosylated alpha-rhamnopyranose and alpha-mannopyranose residues is based on evaluation of the 13C NMR spectra, using glycosylation effects and their deviations from additivity (delta delta values) at the branch points. This approach, in combination with monosaccharide and methylation analysis data, has been verified on a series of bacterial polysaccharides of known structure.

Carbohydrate Sequence↗
PubMed1992

The O18 antigens (lipopolysaccharides) of Escherichia coli. Structural characterization of the O18A, O18A1, O18B and O18B1-specific polysaccharides.

The O-specific polysaccharide moieties (PS) of the O18A, O18A1, O18B, and O18B1 antigens (lipopolysaccharides, LPS) consist of L-rhamnose (Rha), N-acetyl-D-glucosamine, D-galactose, and D-glucose in different molar ratios. By using chemical fragmentation, methylation, as well as one- and two-dimensional NMR spectroscopy, the structures of these polysaccharides were found to be [formula: see text] In O18A-PS and O18A1-PS x = 2, whereas in O18B-PS and in O18B11-PS x = 3. In all four polysaccharides alpha-D-Galp (residue D) is substituted at O-3. This substituent L (residue E) is beta-D-GlcpNAc-(1 in O18A-PS and O18A1-PS and it is alpha-D-Glcp-(1 in O18B-PS and O18B1-PS. Whereas there is no further substituent on the main chain of the O18A and O18B polysaccharides, in O18A1-PS and O18B1-PS the alpha-D-GlcpNAc residue A is substituted with alpha-Glcp-(1 (residue F), which is linked to O-6 in O18A1-PS and to O-4 in O18B1-PS. These results show that the O18 antigen comprises a group of four related LPS (O18A and O18B, with their glucosylated forms O18A1 and O18B1). The results are discussed with respect to epitope definition and biochemical implications.

Carbohydrate Conformation↗
PubMed1992

Structure of the polysaccharide chains of Pseudomonas pseudomallei lipopolysaccharides.

The pathogenic bacterium Pseudomonas pseudomallei strain 57576 produces two partially O-acetylated O-antigenic polysaccharides (PS-I and PS-II). Methylation analysis and 1H and 13C NMR spectroscopy, including NOE experiments, showed PS-I to have the structure [formula: see text] and PS-II to have the structure [formula: see text] where 6dmanHep is the unusual higher sugar 6-deoxy-D-manno-heptose. PS-II is produced also by P. pseudomallei strains 100 and 110, and PS-I and O-deacetylated PS-II by strain 97.

Burkholderia pseudomallei↗
PubMed1992

The structure of the O-specific polysaccharide chain of the lipopolysaccharide of Salmonella arizonae O61.

The O-specific polysaccharide was obtained by mild degradation of the Salmonella arizonae O61 lipopolysaccharide with acid. It contained 2-acetamido-2-deoxy-D-glucose, 2-acetamidino-2,6-dideoxy-L-galactose (FucAm), and 7-acetamido-3,5,7,9-tetradeoxy-5-[(R)-3-hydroxybutyramido]-D- glycero-L-galacto-nonulosonic acid (Sug). On the basis of partial acid hydrolysis with 0.1 M HCl, solvolysis with anhydrous HF in methanol, and 1H- and 13C-NMR analysis (including 1H/13C inversely correlated spectroscopy for localisation of N-acyl substituents), it was concluded that the O-specific polysaccharide had the following structure. ----3)-alpha-L-FucAm-(1----3)-alpha-D-GlcNAc-(1----8)-beta-Sug+ ++-(2---- The O-antigen of S. arizonae O61 is structurally related to that of Pseudomonas aeruginosa O12, thus explaining the known serological cross-reactivity between these micro-organisms.

Carbohydrate Conformation↗