Biomedical subjects

A S Shashkov

Publications and source records attributed to A S Shashkov.

At least 73 records · Page 4Linked to original sources

PubMed2000

Structure of a 2-aminoethyl phosphate-containing O-specific polysaccharide of Proteus penneri 8 from a new serogroup O67.

An acidic O-specific polysaccharide was obtained by mild acid degradation of the Proteus penneri 8 lipopolysaccharide and found to contain D-glucose, D-galacturonic acid, 2-acetamido-2-deoxy-D-glucose, 2-acetamido-2-deoxy-D-galactose, 2-acetamido-2,6-dideoxy-L-galactose (L-FucNAc) and 2-aminoethyl phosphate (PEtn) in the ratios 2 : 1 : 1 : 1 : 1 : 1. 1H and 13C NMR spectroscopy was applied to the intact and dephosphorylated polysaccharides, and the following structure of the hexasaccharide repeating unit was established: The O-specific polysaccharide has a unique structure, and, accordingly, we propose for P. penneri 8 a new Proteus O67 serogroup, in which this strain is at present the single representative. The nature of epitopes on LPS of P. penneri 34, P. mirabilis O16, P. mirabilis O23 and P. vulgaris O22, which cross-react with O-antiserum against P. penneri 8, is discussed.

Animals↗

PubMed2000

Structure of the O polysaccharide and serological classification of Pseudomonas syringae pv. ribicola NCPPB 1010.

The O polysaccharide (OPS) moiety of the lipopolysaccharide (LPS) of a phytopathogenic bacterium Pseudomonas syringae pv. ribicola NCPPB 1010 was studied by sugar and methylation analyses, Smith degradation, and 1H- and 13C-NMR spectroscopy, including 2D COSY, TOCSY, NOESY and H-detected 1H,13C HMQC experiments. The OPS structure was elucidated, and shown to be composed of branched pentasaccharide repeating units (O repeats) of two types, major (1) and minor (2), differing in the position of substitution of one of the rhamnose residues. Both O repeats form structurally homogeneous blocks within the same polysaccharide molecule. Although P. syringae pv. ribicola NCPPB 1010 demonstrates genetic relatedness and similarity in the OPS chemical structure to some other P. syringae pathovars, it did not cross-react with any OPS-specific mAbs produced against heterologous P. syringae strains. Therefore, we propose to classify P. syringae pv. ribicola NCPPB 1010 in a new serogroup, O8.

Carbohydrate Conformation↗

PubMed2000

Structure of the O-specific polysaccharide of the bacterium Proteus mirabilis O29.

An O-specific polysaccharide was obtained by mild acid degradation of P. mirabilis O29 lipopolysaccharide (LPS) and found to contain 2-acetamido-2-deoxy-D-galactose and D-glucuronic acid (D-GlcA) in the ratio 3:1. Studies of the polysaccharide by 1H- and 13C-NMR spectroscopy including two-dimensional correlation spectroscopy (COSY), total correlation spectroscopy (TOCSY), nuclear Overhauser effect spectroscopy (NOESY), and H-detected 1H,13C-heteronuclear multiple-quantum coherence (HMQC) experiments demonstrated the following structure of the branched tetrasaccharide repeating unit:

Carbohydrate Sequence↗

PubMed2000

[The isolation, preliminary study of structure and physiological activity of water-soluble polysaccharides from squeezed berries of Snowball tree Viburnum opulus].

Water-soluble polysaccharide fractions VO1-VO4 were isolated from the squeezed berries of snowball tree (Viburnum opulus) by successive extraction with water at various temperatures and pH and with aqueous solutions of ammonium oxalate. These fractions were purified by ion-exchange chromatography on DEAE cellulose, and the homogeneity of the purified polysaccharides was determined by gel filtration on Sephacryl S-500. Acidic polysaccharides close to pectins in their sugar composition were found in all the extracts (fractions VO1-1, VO2-1, VO3-2, and VO4-2). Residues of galacturonic acid, galactose, arabinose, and (to a lesser extent) rhamnose are their main constituents. Neutral polysaccharides composed mainly of galactose and mannose residues were additionally found in fractions extracted with acidified water (pH 4.0) and with aqueous ammonium oxalate solutions. Partial acidic hydrolysis and digestion with pectinase of acidic polysaccharides indicated that their carbohydrate backbone consists of alpha-1,4-linked residues of D-galacturonic acid. NMR spectra of acidic polysaccharides (fractions VO3-2 and VO3-3) confirmed this and demonstrated that their side oligosaccharide chains are composed of beta-1,4-linked galactopyranose residues and of terminal and 2,5- and 3,5-substituted residues of alpha-arabinofuranose at a Gal: Ara ratio of 3:1. Some polysaccharides from V. opulus were found to possess an immunostimulating activity: they enhance phagocytosis, in particular, the phagocytic index and the secretion of lysosomal enzymes with peritoneal macrophages. Calcium ions were found to be necessary for the appearance of the stimulating effect of acidic polysaccharides from V. opulus.

Adjuvants, Immunologic↗

PubMed2000

Structure of a teichoic acid from Nocardioides luteus VKM Ac-1246T cell wall.

A teichoic acid from the cell walls of Nocardioides luteus VKM Ac-1246T, a validly described species of the Nocardioides genus, is a 1,5-poly(ribitol phosphate) completely substituted at C-4 by alpha-D-galactopyranosyl residues carrying a 4,6-pyruvate ketal group in R-configuration. The structure of the repeating unit of the polymer is as follows: [figure]. The chain consists of approximately 18 repeating units and six beta-D-galactofuranosyl residues linked in the oligomer by 1,6-glycosidic bonds. The oligomer probably terminates the growing end of the teichoic acid. The structure of the polymer was determined by chemical methods and NMR spectroscopy. This teichoic acid has not been described so far.

Actinomycetales↗

PubMed2000

Structure of an acidic O-specific polysaccharide of the bacterium Providencia alcalifaciens O7.

An acidic O-specific polysaccharide was obtained by mild acid degradation of the lipopolysaccharide of the bacterium Providencia alcalifaciens O7 and purified by gel chromatography followed by anion-exchange chromatography. On the basis of full acid hydrolysis, methylation, carboxyl reduction, selective cleavage with anhydrous hydrogen fluoride, and 1H- and 13C-NMR spectroscopy, including two-dimensional 1H,1H homonuclear and H-detected 1H,13C heteronuclear correlation spectroscopy and nuclear Overhauser effect spectroscopy (NOESY), the following structure of the linear tetrasaccharide repeating unit of the polysaccharide was established: [figure], where Rhap2Ac is 2-O-acetylrhamnopyranose.

Carbohydrate Conformation↗

PubMed2000

[Isolation and structural study of polysaccharides from campion Silene vulgaris].

Silenan SV, a pectic polysaccharide, was isolated from the aerial part of Silene vulgaris (Moench) Garke (Oberna behen (L.) Ikonn.), widespread through the European North of Russia. The polysaccharide was found to contain residues of galacturonic acid (63%), arabinose, galactose, and rhamnose as the main constituents. The results of a partial acidic hydrolysis, pectinase digestion, and NMR studies of silenan SV indicated that its molecule contains a linear alpha-1,4-D-galacturonan backbone and ramified regions. The core of the ramified regions is composed of residues of alpha-1,4-D-galacturonic acid along with 2-substituted alpha-rhamnopyranose residues. The NMR data showed that the silenan SV side chains are composed of the blocks built from the terminal alpha-1,5-linked arabinofuranose and beta-1,4-linked galactopyranose residues; these most likely are the side chains of rhamnogalacturonan, characteristic of other pectic polysaccharides. The nonreducing ends of these side chains contain alpha-arabinofuranose residues.

Hydrolysis↗

PubMed2000

Structure of the O-specific polysaccharide of the bacterium Proteus vulgaris O23.

An acidic O-specific polysaccharide was obtained by mild acid degradation of the lipopolysaccharide of the bacterium Proteus vulgaris O23 (strain PrK 44/57) and found to contain 2-acetamido-2-deoxy-D-galactose, 2-acetamido-2-deoxy-D-glucose, and D-galacturonic acid. Based on 1H- and 13C-NMR spectroscopic studies, including two-dimensional correlation spectroscopy (COSY), total correlation spectroscopy (TOCSY), nuclear Overhauser effect spectroscopy (NOESY), and 1H,13C heteronuclear multiple-quantum coherence (HMQC) experiments, the following structure of the branched tetrasaccharide repeating unit of the polysaccharide was established: [figure], where the degree of O-acetylation of the terminal GalA residue at position 4 is about 80%. A structural similarity of the O-specific polysaccharides of P. vulgaris O23 and P. mirabilis O23 is discussed.

Acetylation↗

PubMed2000

Structure of an acidic O-specific polysaccharide of the marine bacterium Pseudoalteromonas sp. KMM 634.

An acidic O-specific polysaccharide containing D-glucuronic acid (D-GlcA), 2,3-diacetamido-2,3-dideoxy-D-glucuronic acid (D-GlcNAc3NAcA), 2,3-diacetamido-2,3-dideoxy-D-mannuronoyl-L-alanine (D-ManNAc3NAcA6Ala), and 2-acetamido-2,4, 6-trideoxy-4-[(S)-3-hydroxybutyramido]-D-glucose (D-QuiNAc4NAcyl) was obtained by mild acid degradation of the lipopolysaccharide of the bacterium Pseudoalteromonas sp. KMM 634 followed by gel-permeation chromatography. The polysaccharide was cleaved selectively with a new solvolytic agent, trifluoromethanesulfonic acid, to give a disaccharide and a trisaccharide with D-GlcNAc3NAcA at the reducing end. The borohydride-reduced oligosaccharides and the initial polysaccharide were studied by GLC-MS and 1H- and 13C-NMR spectroscopy, and the following structure of the linear tetrasaccharide repeating unit of the polysaccharide was established: -->3)-alpha-D-QuipNAc4Ac4NAcyl-(1-->4)-beta-D-ManpNAc3NAcA6Ala+ ++-(1-->4)-b eta-D-GlcpNAc3NAc3NAcA-(1-->4)-beta-D-GlcpA-(1-->.

Carbohydrate Sequence↗

PubMed2000

Structure of anionic carbohydrate-containing cell wall polymers in several representatives of the order actinomycetales.

A new teichoic acid was identified in the cell walls of Streptomyces griseoviridis VKM Ac-622T, Streptomyces sp. VKM Ac-2091, and Actinoplanes campanulata VKM Ac-1319T. The polymer is poly(glycosylglycerol phosphate). The repeating units of the polymer, alpha-galactopyranosyl-(1-->3)-2-acetamido-2-deoxy-beta-galactopyran+ ++ osyl-(1-->1)-glycerols, are in phosphodiester linkage at C-3 of glycerol and C-6 of galactose. The structures of cell wall teichoic acids in the strains Streptomyces chryseus VKM Ac-200T and "Streptomyces subflavus" VKM Ac-484 similar in morphology and growth characteristics are also identical: 1,5-poly(ribitol phosphate) substituted at C-4(2) by 2-acetamido-2-deoxy-beta-glucopyranosyl residues and 1,3-poly(glycerol phosphate). The taxonomic aspects of these results are discussed.

Actinomycetales↗

PubMed2000

[Structure and physiological activity of lemnan, Lemna minor L. pectin].

A pectic polysaccharide, lemnan, was isolated from freshly collected duckweed Lemna minor L. Its sugar chain was shown to be mainly composed of the residues of D-galacturonic acid (64%), galactose, arabinose, xylose, and D-apiose, a branched chain sugar. The high content of D-apiose (25%) indicated that lemnan is an apiogalacturonan type pectin similar to zosteran, a pectic polysaccharide from a sea phanerogam of the Zosteraceae family. The results of partial acidic hydrolysis, pectinase digestion, and NMR studies of lemnan demonstrated that its macromolecule contains regions of the linear alpha-1,4-D-galacturonan and branched apiogalacturonan. The side chains of apiogalacturonan were found to be formed of single and 1,5-linked residues of D-apiofuranose attached to 2- and 3-positions of the D-galacturonic acid residues of the apiogalacturonan backbone. Lemnan was shown to exhibit an immunomodulatory effect by activating the system of phagocytosis.

Adjuvants, Immunologic↗

PubMed1999

Structures of the O-specific polysaccharides and a serological cross-reactivity of the lipopolysaccharides of Proteus mirabilis O24 and O29.

Strains of Proteus mirabilis belonging to serogroups O24 and O29 are frequent in clinical specimens. Anti-P. mirabilis O24 serum cross-reacted with the lipopolysaccharide (LPS) of P. mirabilis O29 and vice versa. The structures of the O-specific polysaccharides (OPSs, O-antigens) of both LPSs were established using sugar analysis and one- and two-dimensional 1H- and 13C-NMR spectroscopy and found to be different. SDS-PAGE and Western immunoblotting suggested that the serological cross-reactivity of the LPSs is due to a common epitope(s) on the core-lipid A moiety, rather than on the OPS. Therefore, the epitope specificity and the structures of the O-antigens studied are unique among Proteus serogroups.

Antibodies, Bacterial↗

PubMed1999

A study of fucoidan from the brown seaweed Chorda filum.

Fucoidan fractions from the brown seaweed Chorda filum were studied using solvolytic desulfation. Methylation analysis and NMR spectroscopy were applied for native and desulfated polysaccharides. Homofucan sulfate from C. filum was shown to contain poly-alpha-(1-->3)-fucopyranoside backbone with a high degree of branching, mainly of alpha-(1-->2)-linked single units. Some fucopyranose residues are sulfated at O-4 (mainly) and O-2 positions. Some alpha-(1-->3)-linked fucose residues were shown by NMR to be 2-O-acetylated. The 1H and 13C NMR spectra of desulfated, deacetylated fucan were completely assigned. The spectral data obtained correspond to a quasiregular polysaccharide structure with a branched hexasaccharide repeating unit. Other fucoidan fractions from C. filum have more complex carbohydrate composition and give rather complex methylation patterns. [formula: see text]

Carbohydrate Conformation↗

PubMed1999

The O-chain polysaccharide of the lipopolysaccharide of Xanthomonas campestris pv. begoniae GSPB 525 is a partially L-xylosylated L-rhamnan.

The O-chain polysaccharide (OPS) of the lipopolysaccharide of Xanthomonas campestris pv. begoniae GSPB 525 was found to contain L-rhamnose and L-xylose in the ratio 1:0.6. The OPS lacked strict regularity because of nonstoichiometric xylosylation of the main rhamnan chain. Based on methylation analysis, Smith degradation, and 1H and 13C NMR spectroscopy, including COSY, TOCSY, NOESY, and H-detected 1H,13C heteronuclear multiple-quantum coherence (HMQC) experiments, the following structure of the OPS was established: [formula: see text].

Carbohydrate Sequence↗

PubMed1999

Chemical structure of a polysaccharide from Campylobacter jejuni 176.83 (serotype O:41) containing only furanose sugars.

A neutral polysaccharide was obtained by hot phenol-water extraction of biomass from Campylobacter jejuni 176.83 and subsequently separated from acid-liberated core oligosaccharide of lipopolysaccharide by sequential GPC on Bio-Gel P6 and TSK-40 columns. All sugar components of the trisaccharide repeating unit of the polysaccharide were found to be of the furanose ring form. The major trisaccharide contained beta-L-arabinose, 6-deoxy-beta-D-altro-heptose (beta-D-6d-altHep) and 6-deoxy-beta-L-altrose (beta-L-6d-Alt), whereas in the minor trisaccharide the beta-L-6d-Alt is replaced by its C-5 epimer alpha-D-Fuc. On the basis of 1H and 13C NMR spectroscopic studies, including 2D ROESY, HMQC and HMQC-TOCSY experiments, the following structures of the repeating units were established: [formula: see text]

Campylobacter jejuni↗

PubMed1999

Structure of an acidic O-specific polysaccharide of Proteus mirabilis O5.

The following structure of the O-specific polysaccharide of Proteus mirabilis O5 was established by 1H and 13C NMR spectroscopy at 500 MHz, including two-dimensional COSY, TOCSY, NOESY, and H-detected 1H, 13C heteronuclear multiple-quantum coherence (HMQC) experiments: [formula: see text] where O-acetylation of alpha-D-GlcNAc at both positions is nonstoichiometric.

Acids↗

PubMed1999

Structure of a new acidic O-antigen of Proteus vulgaris O22 containing O-acetylated 3-acetamido-3,6-dideoxy-D-glucose.

The acidic O-specific polysaccharide of Proteus vulgaris O22 was studied using 1H and 13C NMR spectroscopy, including 2D COSY, TOCSY, NOESY, and H-detected 1H, 13C heteronuclear multiple-quantum coherence (HMQC) experiments, and the following structure for the branched pentasaccharide repeating unit was established: [sequence: see text] where Qui3NAc is 3-acetamido-3,6-dideoxyglucose, O-acetylation of QuiNAc at position 4 is stoichiometric and at position 2 nonstoichiometric. Serological relationships of P. vulgaris O22 with some other Proteus strains were substantiated on the level of the O-antigen structures.

Acetylglucosamine↗

PubMed1999

Structure and cross-reactivity of the O-antigen of Proteus vulgaris O8.

A high-molecular-mass O-specific polysaccharide was obtained by mild acid degradation of Proteus vulgaris O8 lipopolysaccharide followed by gel permeation chromatography. Studies of the polysaccharide by sugar and methylation analyses and 1H and 13C NMR spectroscopy, including 2D COSY, TOCSY, NOESY, and H-detected 1H, 13C heteronuclear multiple-quantum coherence (HMQC) experiments, demonstrated the presence of a tetrasaccharide repeating unit having the following structure: [sequence: see text] The role of an epitope associated with the alpha-L-FucpNAc-(1-->3)-D-GlcpNAc disaccharide in serological cross-reactivity of P. vulgaris O8 is discussed.

Carbohydrate Conformation↗