Structure of the exopolysaccharide produced by Streptococcus thermophilus S3

The exopolysaccharide of Streptococcus thermophilus S3, produced in skimmed milk, is composed of D-galactose and L-rhamnose in a molar ratio of 2:1. The polysaccharide contains 0.4 equiv of O-acetyl groups per repeating unit. Linkage analysis and 1D/2D NMR (1H and 13C) studies on native and O-deacetylated EPS together with nanoES-CID tandem mass spectrometry studies on oligosaccharides generated by a periodate oxidation protocol, show the polysaccharide to have the following structure: [structure: 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.     

Structural investigation of a polysaccharide (Fr. II) isolated from the aqueous extract of an edible mushroom, Pleurotus sajor-caju

A water-soluble polysaccharide, (Fr. II) isolated from aqueous extract of an edible mushroom Pleurotus sajor-caju, was found to consist of D-glucose, D-galactose, and D-mannose in a molar proportion of 1:1:1. Compositional analysis, methylation analysis, periodate oxidation study, partial hydrolysis, and NMR experiments ((1)H, (13)C, 2D-COSY, TOCSY, NOESY, HSQC, and HMBC) revealed the presence of the following repeating unit in the polysaccharide: [formula: see text]     

Structural analysis of an extracellular polysaccharide produced by Rhodococcus rhodochrous strain S-2

A possibility has been suggested of applying the EPS produced by Rhodococcus rhodochrous strain S-2 (S-2 EPS) to the bioremediation of oil-contaminated environments, because its addition, together with minerals, to oil-contaminated seawater resulted in emulsification of the oil, increased the degradation of polyaromatic hydrocarbons (PAH) of the oil, and led to the dominance of PAH-degrading marine bacteria. To understand the underlying principles of these phenomena, we determined the chemical structure of the sugar chain of S-2 EPS. The EPS was found to be composed of D-galactose, D-mannose, D-glucose, and D-glucuronic acid, in a molar ratio of 1:1:1:1. In addition, 0.8% (w/w) of octadecanoic acid and 2.7% (w/w) of hexadecanoic acid were also contained in its structure. By 1H and 13C NMR spectroscopy, including 2D DQF-COSY, TOCSY, HMQC, HMBC, and NOESY experiments, as well as chemical and enzymatic analyses, the polysaccharide was shown to consist of tetrasaccharide repeating units with the following structure: (see formula in text).     

The O-specific chain structure of the major component from the lipopolysaccharide fraction of Halomonas magadii strain 21 MI (NCIMB 13595)

An O-specific polysaccharide containing D-galactose and D-glucose, was isolated from the water-soluble lipopolysaccharide fraction of the alkaliphilic bacterium Halomonas magadii. The structure, determined by means of chemical analysis and 1D and 2D NMR spectroscopy, showed a trisaccharide repeating unit, as shown below: [structure: see text]     

Application of high-resolution n.m.r. spectroscopy to the elucidation of the structure of the specific capsular polysaccharide of Streptococcus pneumoniae type 7F

The specific capsular polysaccharide of Streptococcus pneumoniae type 7F (American type 51) is a high-molecular-weight neutral polymer composed of 2-acetamido-2-deoxy-D-galactose, 2-acetamido-2-deoxy-D-glucose, D-glucose, D-galactose, L-rhamnose, and 2-O-acetyl-L-rhamnose residues. N.m.r. spectroscopy (1H and 13C), in conjunction with composition and methylation analyses, and periodate oxidation data, showed the polysaccharide to be a branched polymer with a repeating heptasaccharide unit having the following structure. (formula; see text)     

Occurrence of two extracellular acidic polysaccharides as products of Rhizobium meliloti 201

The extracellular polysaccharide of Rhizobium meliloti 201 consists of two acidic polysaccharides, APS-I and APS-II. APS-I is composed of D-glucose, D-mannose and D-glucuronic acid in a molar ratio of 3:3:2, whereas APS-II is composed of D-glucose, D-galactose, D-mannose and pyruvic acid in a molar ratio of 4:3:2:1.APS-II was separated from the extracellular polysaccharide preparation by hydrolysing APS-I to its octasaccharide repeating unit with a specific enzyme. APS-I and APS-II were also separated by treatment with cetylpyridinium chloride and by paper electrophoresis of the depyruvylated polysaccharide.     

Structural elucidation of a 3-O-methyl-D-galactose-containing neutral polysaccharide from the fruiting bodies of Phellinus igniarius

PIP60-1, a novel heteropolysaccharide isolated from fruiting bodies of the medicinal fungus, Phellinus igniarius, has a molecular weight of 1.71 x 10(4)Da and is composed of L-fucose, D-glucose, D-mannose, D-galactose and 3-O-Me-D-galactose in a ratio of 1:1:1:2:1. A structural investigation of PIP60-1 carried out using sugar and methylation analyses, combined with (1)H and (13)C NMR spectroscopy, including COSY, TOCSY, NOESY, HSQC and HMBC experiments, established the repeating unit of the polysaccharide as the following: [structure: see text]     

Isolation and characterization of the exopolysaccharide produced by Streptococcus thermophilus SFi20

This paper reports isolation, structural characterization and some physico-chemical properties in aqueous solution of the exopolysaccharide (EPS) produced by Streptococcus thermophilus strain SFi20. The yield of the purified EPS was found to be reproducible and close to the average value of 143 mg/l. The chemical structure, previously suggested, has been confirmed on the basis of NMR data. Viscometric, chiro-optical and rheological measurements have been carried out with the aim of characterizing the conformational state of the polysaccharide in aqueous solution. All the data reported indicate that the EPS does not undergo a cooperative conformational transition under the investigated experimental conditions. Furthermore, the viscosity data and the viscoelastic behaviour suggest that the polymer is rather flexible and adopts a random coil conformation in aqueous solution.     

Structural analysis of an extracellular polysaccharide produced by a benzene tolerant bacterium, Rhodococcus sp. 33

Rhodococcus sp. 33 can tolerate and efficiently degrade various concentrations of benzene, one of the most toxic and prevailing environmental pollutants. This strain produces a large quantity of extracellular polysaccharide (33 EPS), which plays an important role in the benzene tolerance in Rhodococcus sp. 33, especially by helping the cells to survive an initial challenge with benzene. This EPS has been reported to be composed of D-galactose, D-glucose, D-mannose, D-glucuronic acid, and pyruvic acid at a molar ratio of 1:1:1:1:1. To understand the protective effect of 33 EPS, we determined its chemical structure by using 1H and 13C NMR spectroscopy including 2D DQF-COSY, TOCSY, HMQC, HMBC, and NOESY experiments. The polysaccharide was shown to consist of tetrasaccharide repeating units with the following structure: [structure: see text].     

Structure of the capsular polysaccharide of Actinobacillus pleuropneumoniae serotype 5b.

The capsular polysaccharide of Actinobacillus pleuropneumoniae serotype 5b (strain L20) was found to be a high molecular mass polymer composed of 2-acetamido-2-deoxy-D-glucose, D-glucose, and 3-deoxy-D-manno-octulosonic acid (KDO). Methylation analysis, partial hydrolysis and a combination of homonuclear and 1H-detected heteronuclear shift-correlated nuclear magnetic resonance experiments showed the polysaccharide to be a branched polymer of a trisaccharide repeating unit, having the structure: [formula; see text]     

Structure of the specific capsular polysaccharide of Streptococcus pneumoniae type 23F (American type 23)

The specific capsular polysaccharide of Streptococcus pneumoniae serotype 23F (American type 23) is composed of a repeating tetrasaccharide unit containing D-glucose (one part), D-galactose (one part), L-rhamnose (two parts), glycerol (one part), and phosphate (one part). By composition analysis, optical rotation, partial hydrolysis, periodate oxidation, methylation, and high-resolution 1H and 13C nuclear magnetic resonance studies, the elucidated unambiguous structure was in agreement with our earlier proposal but is at variance with structures proposed later by other authors. The structure of the type 23F pneumococcal polysaccharide is (formula; see text).     

Isolation and characterization of a heteroglycan from the fruits of Astraeus hygrometricus

A water-soluble polysaccharide was isolated from an alkaline extract of the fruits of the ectomycorrhizal fungus, Astraeus hygrometricus. It was found to contain D-mannose, D-glucose, and L-fucose in a molar ratio of 1:2:1. On the basis of total hydrolysis, methylation analysis, periodate oxidation, Smith degradation, and NMR studies (1H, 13C, DQF-COSY, TOCSY, NOESY, ROESY, HMQC, and HMBC) the structure of the repeating unit of the polysaccharide was established as [Formula: see text]     

Structural characterisation of the exopolysaccharide produced by Streptococcus thermophilus EU20

Streptococcus thermophilus EU20 when grown on skimmed milk secretes a high-molecular-weight exopolysaccharide that is composed of glucose, galactose and rhamnose in a molar ratio of 2:3:2. Using chemical techniques and 1D and 2D-NMR spectroscopy (1H and 13C) the polysaccharide has been shown to possess a heptasaccharide repeating unit having the following structure: [chemical structure: see text]. Treatment of the polysaccharide with mild acid (0.5 M TFA, 100 degrees C for 1 h) liberates two oligosaccharides; the components correspond to the repeating unit and a hexasaccharide equivalent to the repeating unit minus the terminal alpha-L-Rhap.     

Structural characterisation and enzymic modification of the exopolysaccharide produced by Lactococcus lactis subsp. cremoris B39

Lactococcus lactis subsp. cremoris B39 grown on whey permeate produced an exopolysaccharide containing L-Rha, D-Gal and D-Glc in a molar ratio of 2:3:2. The polysaccharide was modified using an enzyme preparation from Aspergillus aculeatus, resulting in the release of Gal and a polymer with approximately the same hydrodynamic volume as the native polysaccharide. Linkage analysis and 1H NMR studies of both the native and modified exopolysaccharides elucidated that terminally linked Gal was released during modification and that the chemical structure of the branches within the repeating units is: beta-D-Galp-(1-->4)-beta-D-Glcp-(1-->. 2D NMR experiments (both 1H-1H and 1H-13C) revealed that exopolysaccharide B39 consists of a branched heptasaccharide repeating unit with the following structure: [structure: see text].     

Chemical and immunochemical studies of the O-antigen from enteropathogenic Escherichia coli O158 lipopolysaccharide

The O-specific polysaccharide isolated from Escherichia coli O158 smooth lipopolysaccharide contains L-rhamnose, D-glucose and 2-acetamido-2-deoxy-D-galactose in the molar ratios 1:2:2. Studies on composition, methylation analysis and specific degradations together with a 1H and 13C NMR spectral study established that the O-antigen is built up from a pentasaccharide repeating unit having the following structure: [formula: see text] The most effective inhibitory part of the oligosaccharide from E. coli O158 lipopolysaccharide has been serologically characterized by an ELISA-inhibition study using different sugars. The results showed that methyl alpha- and beta-D-GalpNAc are the most effective inhibitors among the monosaccharides tested, while the main antibody specificity lies on the main-chain trisaccharide repeating unit.     

Characterization of the lipopolysaccharide O-antigen of Cronobacter turicensis HPB3287 as a polysaccharide containing a 5,7-diacetamido-3,5,7,9-tetradeoxy-D-glycero-D-galacto-non-2-ulosonic acid (legionaminic acid) residue

Cronobacter turicensis, previously known as Enterobacter sakazakii, is a Gram-negative opportunistic food-borne pathogen that has been reported as a cause of life-threatening neonatal infections. From chemical and physical analyses involving composition analysis, methylation, two-dimensional high-resolution nuclear magnetic resonance, and mass spectrometry methods, the antigenic O-polysaccharide in the smooth-type lipopolysaccharide of C. turicensis (strain HPB 3287) was determined to be a high molecular mass polymer of a repeating pentasaccharide unit composed of D-galactose, D-glucose, 2-acetamido-2-deoxy-D-galactose, and 5,7-diacetamido-3,5,7,9-tetradeoxy-D-glycero-D-galacto-non-2-ulosonic acid (legionaminic acid), in a molar ratio 2:1:1:1, and having the structure: [see formula in text].     

The specific capsular polysaccharide of Streptococcus pneumoniae type 9V

The specific capsular polysaccharide produced by Streptococcus pneumoniae type 9V (American type 68) is composed of D-glucuronic acid (1 part), D-galactose (1 part), 2-acetamido-2-deoxy-D-mannose (1 part), D-glucose (2 parts), and O-acetyl (1.6 parts). Methylation, periodate oxidation, optical rotation, and nuclear magnetic resonance studies, and partial hydrolysis showed that the polysaccharide is an unbranched high molecular weight linear polymer of a partially O-acetylated pentasaccharide repeating unit having the structure indicated below. (Formula: see text).     

Structure of the capsular polysaccharide of Klebsiella serotype K40

The capsular polysaccharide from Klebsiella Serotype K40 contains D-galactose, D-mannose, L-rhamnose, and D-glucuronic acid in the ratios of 4:1:1:1. Methylation analysis of the native and carboxyl-reduced polysaccharide provided information about the glycosidic linkages in the repeating unit. Degradation of the permethylated polymer with base established the identity of the sugar unit preceding the glycosyluronic acid residue. The modes of linkages of different sugar residues were further confirmed by Smith degradation and partial hydrolysis of the K40 polysaccharide. The anomeric configurations of the different sugar residues were determined by oxidation of the peracetylated native and carboxyl-reduced polysaccharide with chromium trioxide. Based on all of these results, the heptasaccharide structure 1 was assigned to the repeating unit of the K40 polysaccharide. (Formula: see text)     

O-specific polysaccharide of the marine bacterium "Alteromonas marinoglutinosa" NCIMB 1770

The O-specific polysaccharide of the marine bacterium "Alteromonas marinoglutinosa" NCIMB 1770 was obtained by mild acid degradation of the corresponding lipopolysaccharide and found to contain D-galactose, N-acetyl-D-glucosamine, and N-acetyl-D-mannosamine residues in equimolar ratio. Based on methylation analysis, periodate oxidation, and 13C-NMR spectroscopy data of native and modified polysaccharides, the following structure of the trisaccharide repeating unit of the O-specific polysaccharide was established: [structure: see text]