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At least 847 records · Page 47Linked to original sources
PubMed2003

Structure of the lipopolysaccharide of Pseudomonas aeruginosa O-12 with a randomly O-acetylated core region.

The lipopolysaccharide of Pseudomonas aeruginosa O-12 was studied by strong alkaline and mild acid degradations and dephosphorylation followed by fractionation of the products by GPC and high-performance anion-exchange chromatography and analyses by ESI FT-MS and NMR spectroscopy. The structures of the lipopolysaccharide core and the O-polysaccharide repeating unit were elucidated and the site and the configuration of the linkage between the O-polysaccharide and the core established. The core was found to be randomly O-acetylated, most O-acetyl groups being located on the terminal rhamnose residue of the outer core region.

Carbohydrate Sequence↗
PubMed1997

Synthesis of L-glycero-D-manno-heptopyranose-containing oligosaccharide structures found in lipopolysaccharides from Haemophilus influenzae.

Syntheses are described of the tetrasaccharide 2-(4-trifluoroacetamidophenyl)ethyl O-(beta-D-galactopyranosyl)-(1-->2)-O- (L-glycero-alpha-D-manno-heptopyranosyl)-(1-->2)-O-(L-glycero-alpha-D- manno-heptopyranosyl)-(1-->3)-L-glycero-alpha-D-manno-heptopyranoside (20) and the three trisaccharides 2-(4-trifluoroacetamidophenyl)ethyl O-(L-glycero-alpha-D-manno-heptopyranosyl)-(1-->2)-O-(L-glycero-alpha-D- manno-heptopyranosyl)-(1-->3)-L-glycero-alpha-D-manno-heptopyranoside (17), 2-(4-trifluoroacetamidophenyl)ethyl O-(beta-D-glucopyranosyl)-(1-->4)- O-(beta-D-glucopyranosyl)-(1-->4)-L-glycero-alpha-D-manno-heptopyrano side (5), and 2-(4-trifluoro-acetamidophenyl)ethyl O-(beta-D-galactopyranosyl)-(1-->4)-O-(beta-D-glucopyranosyl)-(1-->4)- L-glycero-alpha-D-manno-heptopyranoside (8), corresponding to structures found in the lipooligosaccharides of Haemophilus influenzae.

Carbohydrate Conformation↗
PubMed1998

Synthesis and serological characterization of L-glycero-alpha-D-manno-heptopyranose-containing di- and tri-saccharides of the non-reducing terminus of the Escherichia coli K-12 LPS core oligosaccharide.

Synthesis of the title trisaccharide was accomplished by sugar chain extension starting from the non-reducing terminus: coupling of Glcp NAc with LD-Hepp, then adding Glcp-OAll. An alternative route started from the reducing end: coupling of LD-Hepp with Glcp-OAll, then addition of Glcp NAc. In the synthesis of the title disaccharide a modification of the first approach was employed. The allyl glycosides were coupled with cysteamine, activated with thiophosgene and conjugated to bovine serum albumin (BSA). The neoglycoconjugates obtained were used in immunochemical studies of monoclonal and polyclonal antibodies directed against Escherichia coli K-12 lipopolysaccharide.

Carbohydrate Sequence↗
PubMed2000

Synthesis of 6,7-dideoxy-7-isothiocyanatoheptoses: stable fully unprotected monosaccharide isothiocyanates.

Methyl 6,7-dideoxy-7-isothiocyanato-alpha-D-gluco (manno)(galacto)-heptopyranosides have been synthesized in four steps by homologation of the respective methyl hexopyranosides via the corresponding heptopyranosydurononitriles. Neither intra- nor intermolecular thiocarbamate formation was observed, even under rather strenuous acidic or basic conditions. The reducing derivative 6,7-dideoxy-7-isothiocyanato-alpha-D-gluco-heptopyranose was also a stable compound in aqueous solution in the absence of base. Formation of a six-membered intramolecular cyclic thiocarbamate was achieved in DMF solution in the presence of triethylamine. The title compounds are the first examples of stable fully unprotected monosaccharide isothiocyanates.

Dimethylformamide↗
PubMed1969

The nitro sugars.

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Alcohols↗
PubMed1983

Changes in food intake and meal patterns following injection of D-mannoheptulose in rats.

Behavioral and metabolic effects of intraperitoneal D-mannoheptulose (MH) injections were investigated in rats fed a high carbohydrate (HC) or a high fat (HF) diet. Injection of 125 or 250 mg/kg body weight (body wt) MH did not affect food intake in HC rats. Injection of 400 mg/kg body wt MH inhibited feeding in HC rats by primarily reducing meal size. In contrast, none of the MH doses tested (125, 250, 400, 800 mg/kg body wt) affected food intake or meal patterns in HF rats. The hyperglycemia following MH injection (400 mg/kg body wt) was more pronounced in HC compared to HF rats. MH injection (400 mg/kg body wt) induced a strong taste aversion in HC rats, but had only weak aversive consequences in HF rats. The data throw some doubt on the hypothetical role of insulin in the production of satiety. In addition, the results suggest that a hedonic shift takes place following MH injection in HC rats. The strong dislike for the HC diet after MH injection might be triggered by the severe disturbance of glucose homeostasis and might contribute to the transient hypophagia in HC rats by primarily reducing meal size.

Animals↗
PubMed1993

Binding of the substrate analogue perseitol to phosphorylated and unphosphorylated enzyme IImtl of the phosphoenolpyruvate-dependent phosphotransferase system of Escherichia coli.

Enzyme IImtl catalyzes the concomitant transport and phosphorylation of the hexitol mannitol. Here we demonstrate that the heptitol perseitol is not phosphorylated and not transported by the enzyme. However, the enzyme binds perseitol with an affinity comparable to the affinity for mannitol. Apparent affinities of the phosphorylated enzyme for perseitol were inferred from the inhibition by perseitol of mannitol phosphorylation and uptake. Apparent affinities of the unphosphorylated enzyme follow from the inhibition of mannitol binding to the enzyme. Mechanistic interpretations of the apparent inhibition constants are discussed, and it is concluded that phosphorylation of the cytoplasmic domain of enzyme IImtl has little effect on the affinity of the membrane-bound domain of the enzyme for perseitol.

Binding, Competitive↗
PubMed2000

Mass spectral characterization of lipooligosaccharides from Haemophilus influenzae 2019.

Lipooligosaccharide (LOS) glycoforms from Haemophilus influenzae 2019 were profiled using the high-resolution and accurate mass capabilities of Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry. Sequence and linkage for two previously unknown LOS glycoforms were subsequently obtained through MSn analyses on FT-ICR and quadrupole ion trap (qIT) instruments. MSn analysis of negative ion precursors confirmed structural details within the lipid moiety, while CID spectra of sodiated precursor ions provided monosaccharide sequence and linkage for the oligosaccharide portion of the molecule. Results obtained in this study indicate that extensive heterogeneity exists within the oligosaccharide moieties in LOS from H. influenzae 2019. More importantly, the data suggest that additional hexose moieties, which are added onto the LOS, are not simple extensions of one particular core structure but rather that structural isomers with different connectivities are present within the heterogeneous mixture.

Carbohydrate Conformation↗