Structure of acidic O-specific polysaccharide from the marine bacterium Cellulophaga baltica

The structure of an acidic O-specific polysaccharide from the marine bacterium Cellulophaga baltica was established by chemical methods of analysis and NMR spectroscopy. The polysaccharide was shown to consist of repeating tetrasaccharide units containing two mannose residues, one N-acetyl-D-glucosamine residue, and one D-glucuronic acid residue. An O-acetyl group was also found in the polysaccharide in nonstoichiometric amount. Thus, this polysaccharide had the following structure: [carbohydrate structure: in text].     

Structure of an acidic polysaccharide from the agar-decomposing marine bacterium Pseudoalteromonas atlantica strain IAM 14165 containing 5,7-diacetamido-3,5,7,9-tetradeoxy-L-glycero-L-manno-non-2-ulosonic acid

The structure of an acidic polysaccharide from Pseudoalteromonas atlantica strain 14165 containing 5,7-diacetamido-3,5,7,9-tetradeoxy-L-glycero-L-manno-non-2-ulosonic acid (di-N-acetylpseudaminic acid, Pse5Ac7Ac) has been elucidated. The polysaccharide was studied by 1H and 13C NMR spectroscopy, including 2D experiments, along with sugar and methylation analyses. After a selective hydrolysis a modified polysaccharide devoid of its side chain could be isolated. It was found that the polysaccharide has pentasaccharide repeating units with following structure: [structure: see text].     

Structural studies of the capsular polysaccharide from streptococcus pneumoniae type 37

The structure of the capsular polysaccharide elaborated by Streptococcus pneumonia type 37 has been investigated; methylation analysis, Smith degradation, and n.m.r. spectroscopy were the principal methods used. It is concluded that the polysaccharide is composed of disaccharide repeating-units having the following structure.

This comb-like structure is very crowded, which influences the n.m.r. spectra of the polysaccharide.     

Structure and serological characteristics of the capsular K4 antigen of Escherichia coli O5:K4:H4, a fructose-containing polysaccharide with a chondroitin backbone

The chemical structure of the K4-specific capsular polysaccharide (K4 antigen) of Escherichia coli O5:K4:H4 was elucidated by composition, carboxyl reduction periodate oxidation methylation nuclear-magnetic-resonance spectroscopy and enzymatic cleavage. The polysaccharide consists of a backbone with the structure----3)-beta-D-glucuronyl-(1,4)-beta-D-N-acetylgalactosaminyl(1- to which beta-fructofuranose is linked at C-3 of glucuronic acid. Mild acid hydrolysis liberated fructose and converted the K4 antigen into a polysaccharide which has the same structure as chondroitin. The defructosylated polysaccharide was a substrate for hyaluronidase and chondroitinase. The serological reactivity of the K4 polysaccharide was markedly reduced after defructosylation.     

Full assignment of the proton and carbon NMR spectra and revised structure for the capsular polysaccharide from Streptococcus pneumoniae type 17F

Full proton, 13C and 31P NMR assignments for the capsular polysaccharide from Streptococcus pneumoniae Type 17F are reported, and a revised structure differing in the anomeric configuration of the sidechain beta-Galp residue proposed. This polysaccharide is a component of the current 23-valent polysaccharide vaccine. The implications of this revised structure for published work are discussed.     

A structural investigation of the capsular polysaccharide of Klebsiella K69

The structure of the capsular polysaccharide isolated from Klebsiella serotype K69 has been investigated by a combination of chemical and spectroscopic methods. The repeating structure of the deacetylated polysaccharide is shown to be of the "3 + 1 + 1" type, and it carries a 1-carboxyethylidene acetal at positions 4 and 6 of a terminal galactosyl group. The location of acetyl groups in the polysaccharide has not been established. The repeating unit of the deacetylated polysaccharide has the following structure. (Formula: see text).     

Structure of the repeating chain of the O-specific polysaccharide of Vibrio fluvialis

O-Specific polysaccharide chain of the Vibrio fluvialis lipopolysaccharide is built up of pentasaccharide repeating units, containing one N-acetyl-D-glucosamine and four L-rhamnose residues. The structure of the polysaccharide was elucidated using two-dimensional correlation 1H-NMR-spectroscopy, 13C-NMR-spectroscopy and nuclear Overhauser effect and confirmed by methylation analysis and selective cleavage of N-acetylglucosamine residues by the N-deacetylation-deamination method which yielded linear L-rhamnan representing the backbone of the polysaccharide. Thus, the repeating unit of the O-specific polysaccharide has the following structure: (formula; see text)     

Structure of an O-specific polysaccharide of Proteus mirabilis 03, containing N-(2-hydroxyethyl)-D-alanine

O-Specific polysaccharide, obtained by mild acid degradation of the Proteus mirabilis 03 lipopolysaccharide, 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, the 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 elucidated by using 1H and 13C NMR spectroscopy and mass spectrometry (applied to the acetylated methyl ester derivative), optical rotation and CD spectrum data and comparison with the synthetic sample. The repeating unit of P. mirabilis 03 O-specific polysaccharide is shown to have the following structure: (formula; see text)     

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.     

Microscopic and chemical studies of a gelling polysaccharide from Lactobacillus hilgardii

The bacterium Lactobacillus hilgardii (previously named L. brevis), isolated from sugary kefir grains, has been found to produce a gelling extracellular polysaccharide. Methylation analysis and ¹H- and ¹³C-NMR analysis revealed a dextran-like structure for the polysaccharide. A high proportion of -(1,6)-Glc and small proportions of -(1,3,6)-Glc, -(1,4,6)-Glc and terminal -Glc were detected. The L. hilgardii polysaccharide differed from normal dextrans in containing a small proportion of -(1,3)-Glc. The structure of the polysaccharide was found to be independent of harvesting time and unaffected by changes in the growth medium. The development of the gel structure has been followed by transmission electron microscopy.     

The structure of a repetitive unit of the glycerolphosphate- containing O-specific polysaccharide chain from Yersinia kristensenii strain 103 (0:12,26) lipopolysaccharide]

Mild acid hydrolysis of the lipopolysaccharide from Yersinia kristensenii strain 103 (0:12.26) afforded teichoic acid-like polysaccharide. From the results of methylation, dephosphorylation, partial Smyth degradation, and 13C and 31P NMR data the structure of the repeating unit of the polysaccharide was deduced as follows: [formula: see text] The structure was confirmed by complete interpretation of polysaccharide 13C NMR spectrum.     

Structural studies of the capsular polysaccharide of Klebsiella type 52

The structure of the capsular polysaccharide from Klebsiella Type 52 has been investigated. Methylation analysis, characterization by gas-liquid chromatography-mass spectrometry of oligosaccharide derivatives obtained on partial hydrolysis of the methylated polysaccharide with acid, and specific degradation of the methylated polysaccharide by successive treatments with base and acid followed by characterization of the product, were the principal methods used. The polysaccharide is composed of hexasaccharide repeating-units containing D-glucuronic acid, D-galactose, and L-rhamnose, in the ratios 1:3:2. A structure for these units, disregarding the anomeric natures of the sugar residues, is proposed.     

细菌荚膜多糖

随着分子生物学、糖化学和免疫学的发展,细菌荚膜多糖的研究逐步深入.不仅对其特性及组成有了进一步的了解,而且对其多糖合成相关基因、合成调节和致病性进行了更为细致的研究.本文概括了细菌荚膜多糖的化学结构、合成相关基因、多样性产生机制、合成调节、功能与致病性和应用前景,总结其研究热点,以期为荚膜多糖的研究和应用提供理论依据和思路.     

Structural studies on Klebsiella type 61 capsular polysaccharide

The capsular polysaccharide from klebsiella type 61 was found to contain d-galactose, d-glucose, d-mannose, and d-glucuronic acid in the ratios 1:2:1:1. Acid hydrolysis of the polysaccharide gave one aldobiouronic acid, whose structure was established. Methylation analysis of the polysaccharide provided information about the linkages in the polysaccharide. The polysaccharide is composed of a pentasaccharide repeating unit for which structures are proposed.     

Structural study on lipid A and the O-specific polysaccharide of the lipopolysaccharide from a clinical isolate of Bacteroides vulgatus from a patient with Crohn's disease.

Bacteroides vulgatus has been shown to be involved in the aggravation of colitis. Previously, we separated two potent virulence factors, capsular polysaccharide (CPS) and lipopolysaccharide (LPS), from a clinical isolate of B. vulgatus and characterized the structure of CPS. In this study, we elucidated the structures of O-antigen polysaccharide (OPS) and lipid A in the LPS. LPS was subjected to weak acid hydrolysis to produce the lipid A fraction and polysaccharide fraction. Lipid A was isolated by preparative TLC, and its structure determined by MS and NMR to be similar to that of Bacteroides fragilis except for the number of fatty acids. The polysaccharide fraction was subjected to gel-filtration chromatography to give an OPS-rich fraction. The structure of OPS was determined by chemical analysis and NMR spectroscopy to be a polysaccharide composed of the following repeating unit: [-->4)alpha-L-Rhap(1-->3)beta-D-Manp(1-->].     

The use of bacteriophage depolymerization in the structural investigation of the capsular polysaccharide from Klebsiella serotype K3

The structure of the repeating unit of the capsular polysaccharide from Klebsiella serotype K3 has been established from the results of n.m.r. (1H and 13C) spectroscopy and methylation analysis of P1, the pyruvic acetal-bearing pentasaccharide obtained on depolymerization of the polysaccharide with a bacteriophage-borne endogalactosidase, reduced deacetalated P1, and the native polysaccharide. The data permit the assignment of the following structure to the repeating unit: (formula see text)     

Structural determination and immunochemical characterization of the type V group B Streptococcus capsular polysaccharide

The type V capsular polysaccharide of group B Streptococcus has been isolated and purified, and its repeating unit structure determined. The native type V polysaccharide contains D-glucose, D-galactose, 2-acetamido-2-deoxy-D-glucose, and sialic acid in a molar ratio of 3:2:1:1. Methylation analysis and 1H NMR and 13C NMR analysis of the native type V polysaccharide and of its specifically degraded products permitted the determination of the repeating unit structure of the type V polysaccharide: [formula: see text] The type V polysaccharide has certain structural features in common with other group B streptococcal capsular polysaccharides but is antigenically distinct: no immunologic cross-reactivity was observed between type V and types Ia, Ib, II, III, or IV polysaccharides. Studies of antibody binding to the partially degraded forms of the type V polysaccharide indicated that the native epitope is complex, involving most if not all of the sugar residues of the repeating unit.     

Structure of the O-specific polysaccharide of Citrobacter braakii O7a,3b,1c.

The following structure of the O-specific polysaccharide of Citrobacter braakii O7a,3b,1c was established using sugar and methylation analyses and NMR spectroscopy, including 2D COSY, TOCSY, NOESY, and 1H, 13C heteronuclear single-quantum coherence (HSQC) experiments: (struture: see text). The main D-mannan chain of the polysaccharide studied has the same structure as the O-specific polysaccharide of Escherichia coli O9, Klebsiella pneumoniae O3, and Hafnia alvei PCM 1223.     

雪松松针多糖超声波酶法提取及其抗氧化性

为优化雪松松针多糖超声波酶法的提取工艺,并研究多糖结构及其抗氧化性。通过响应面法分析确定最佳提取参数为:3. 0 g松针粉末,液料比20∶1(m L∶g),提取温度80℃,超声功率560 W,超声时间47 min,纤维素酶用量12 FPU/g原料,提取两次,多糖得率高达10. 39%。采用高效液相色谱、红外光谱和核磁共振光谱等对松针多糖进行了结构表征,松针多糖以β-糖苷键为主要连接方式,并由葡萄糖、果糖、阿拉伯糖和半乳糖等单糖组成。体外抗氧化性研究结果表明:松针粗多糖对羟基自由基(·OH)和1,1-二苯基-2-三硝基苯肼自由基(DPPH·)的清除能力远高于纯化多糖,呈现出良好的量效关系,粗多糖对·OH和DPPH·的半抑制浓度IC50分别为0. 47 g/L和0. 076 g/L。     

Structural investigation of a heteroglycan isolated from the fruit bodies of an ectomycorrhizal fungus Astraeus hygrometricus

A polysaccharide fraction (AQS-II) has been isolated from the hot aqueous extract of the fruits of an ectomycorrhizal fungus Astraeus hygrometricus. It was found to contain 63% polysaccharide and 35% protein. The polysaccharide part contains glucose, galactose, and fucose in a 2:1:1 molar ratio. On the basis of total acid hydrolysis, methylation analysis, periodate oxidation, and NMR studies ((1)H, (13)C, DQF-COSY, TOCSY, NOESY, HMBC, and HSQC) the structure of the repeating unit of the polysaccharide was established as [structure: see text].