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PubMed Journal Database | Carbohydrate research RSS

04:04 EDT 25th June 2019 | BioPortfolio

The US National Library of Medicine and National Institutes of Health manage PubMed.gov which comprises of more than 29 million records, papers, reports for biomedical literature, including MEDLINE, life science and medical journals, articles, reviews, reports and  books.

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For example view all recent relevant publications on Epigenetics and associated publications and clincial trials.

Showing PubMed Articles 1–25 of 399 from Carbohydrate research

Practical considerations for printing high-density glycan microarrays to study weak carbohydrate-protein interactions.

Interactions of carbohydrates and proteins are essential for many biological processes and glycan microarrays have emerged as powerful tools to rapidly assess these carbohydrate-protein interactions. Diverse platforms to immobilize glycans on glass slides for subsequent probing of the specificities of glycan-binding proteins (GBPs) have evolved. It has been suggested that high local glycan density on microarrays is crucial for detecting low-affinity interactions. To determine the influence of printing effic...

New furospirostane steroidal saponins from the flowers of Lilium Asiatic hybrids.

Lilium Asiatic hybrids (Lilium spp.) are produced by interspecific crosses of Sinomartagon species belonging to Liliaceae. To date, no phytochemical work appears to have been conducted on Lilium Asiatic hybrids. In the current work, solvent extraction, solvent fractionation, and repeated SiO and ODS column chromatography yielded three new steroidal saponins along with a known one, avenacoside A (1). The chemical structures of the new saponins were determined based on extensive spectroscopic methods as well ...

Characterization of the Salmonella Typhimurium core oligosaccharide and its reducing end 3-deoxy-d-manno-oct-2-ulosonic acid used for conjugate vaccine production.

One of the strategies adopted for the development of a bivalent conjugate vaccine against invasive nontyphoidal Salmonella consists of linking the O-antigen component of S. Typhimurium and S. Entertidis lipopolysaccharides to the carrier protein CRM, a non-toxic variant of diphtheria toxin. The conjugation reaction uses the reducing end residue 3-deoxy-d-manno-oct-2-ulosonic acid (Kdo) of the core to which the O-antigen chain is bound (OAg-core). OAg-core chains are cleaved from the lipid A directly in the ...

β-L-Araf-containing arabinan and glucuronoxylan from guavira fruit pomace.

Guavira is a plant that belongs to Myrtaceae family, being widespread in the Brazilian Cerrado. In this study, pectic and hemicellulosic polysaccharides from guavira pomace, an agroindustry residue from pulp production, were structurally characterized using GPC, monosaccharide composition, methylation and NMR experiments. The absolute configurations of monosaccharides and the nature of uronic acids were attributed according to numerous data on the composition of related plant arabinogalactans and hemicellul...

Synthesis and conformational analysis of poly(phenylacetylene)s with serinol-tethered carbohydrate appendages.

We synthesized phenylacetylenes containing β-lactoside, β-cellobioside, or β-maltoside, and polymerized them to produce the corresponding poly (phenylacetylene)s. In these poly (phenylacetylene)s, the pendent carbohydrates were tethered to the mainchains by serinol spacers. Because similar glycosyl serinol units are found in the natural glycosphingolipids in cell membranes, the densely packed carbohydrate clusters along the poly (phenylacetylene) mainchains act as molecular mimics of cell surface glycocl...

Structure elucidation and gene cluster characterization of the O-antigen of Yersinia kristensenii С-134.

Mild acid degradation of the lipopolysaccharide of Yersinia kristensenii C-134 afforded a glycerol teichoic acid-like O-polysaccharide, which was studied by sugar analysis, O-deacetylation and dephosphorylation along with 1D and 2D NMR spectroscopy. The following structure of the O-polysaccharide was established: This structure is related to those of other Y. kristensenii O-polysaccharides studied earlier. The O-antigen gene cluster of Y. kristensenii С-134 was analyzed and found to be consistent with the ...

A highly active α-cyclodextrin preferring cyclomaltodextrinase from Geobacillus thermopakistaniensis.

Cyclomaltodextrinases show diverse hydrolyzing and/or transglycosylation activities against cyclodextrins, starch and pullulan. A gene annotated as cyclomaltodextrinase from Geobacillus thermopakistaniensis was cloned and overexpressed in Escherichia coli. The gene product, CDase, was purified and biochemically characterized. The recombinant enzyme exhibited highest activity with α-cyclodextrin at 55 °C and pH 6.0. Specific hydrolytic activities towards α-, β- and γ-cyclodextrin were 1200, 735 and 36...

Colitose-containing O-polysaccharide structure and O-antigen gene cluster of Escherichia albertii HK18069 related to those of Escherichia coli O55 and E. coli O128.

A 3,6-dideoxy-l-xylo-hexose (colitose)-containing partially O-acetylated branched polysaccharide was obtained by mild acid hydrolysis (2% HOAc, 100 °C, 2 h) of the lipopolysaccharide of Escherichia albertii HK18069 followed by gel-permeation chromatography on Sephadex G-50 Superfine. Part of colitose residues (~40%) was cleaved upon hydrolysis, and the full cleavage was achieved by prolonged hydrolysis (8 h) under the same conditions and resulted in a modified linear polysaccharide. Structure of the ...

Steady state kinetic analysis of O-linked GalNAc glycan release catalyzed by endo-α-N-acetylgalactosaminidase.

Often glycosidase assays are based on small-molecule compounds where a glycan of interest is linked to a chromophore allowing for easy detection of cleavage of the glycoside bond. However, such compounds only resemble part of the more complex substrate molecule for enzymes acting on glycoconjugates of glycopeptides or glycoproteins. Nonetheless, the advantage is obvious as enzyme activity is readily recorded and kinetic parameters easily obtained. This is not often the case with glycopeptides or glycoprotei...

Synthesis and antiviral activity of some imidazo1,2-b1,3,4thiadiazole carbohydrate derivatives.

Herein we describe the synthesis of imidazo[2,1-b][1,3,4]thiadiazoles from carbohydrates with D-ribo and D-xylo configuration. The antiviral activity of these compounds was tested against Junín virus (the etiological agent of Argentine hemorrhagic fever). The p-chlorophenyl derivatives showed antiviral activity in a range of micromolar concentration.

Scalable, efficient and rapid chemical synthesis of l-Fructose with high purity.

An improved process for chemical synthesis of l-fructose with high purity in large scale from readily available l-sorbose is described. In general, this synthetic scheme is characterized by inexpensive and easily available starting materials, simple and safe experimental procedures, short time period, low environmental impact, and great potential for scaling up. The scale-up experiment (100 g) was carried out to provide 42.7 g of l-fructose with high HPLC purity of 99.65% in total yield of 50.2%. Conseq...

Galactofuranosidase from JHA 19 Streptomyces sp.: subcloning and biochemical characterization.

Despite the crucial role of the rare galactofuranose (Galf) in many pathogenic micro-organisms and our increased knowledge of its metabolism, there is still a lack of recombinant and efficient galactofuranoside hydrolase available for chemo-enzymatic synthetic purposes of specific galactofuranosyl-conjugates. Subcloning of the Galf-ase from JHA 19 Streptomyces sp. and its further overexpression lead us to the production of this enzyme with a yield of 0.5 mg/L of culture. It exhibits substrate specificity ...

Insights into the pH-dependent catalytic mechanism of Sulfolobus solfataricus β-glycosidase: A molecular dynamics study.

Sulfolobus solfataricus β-glycosidase (SS-βGly) belongs to Glycosyl Hydrolase family1 (GH1) with broad substrate specificity. SS-βGly catalyzes both hydrolysis and transglycosylation reactions. SS-βGly is commonly used to synthesize variety of galacto-oligosaccharides. A comparison of SS-βGly with bacterial and eukaryotic homologs, using DALI search, revealed unique inserts. Free enzyme molecular dynamics (MD) simulation was performed under two different pH conditions (pH 6.5 and 2.5) at a constant tem...

Complex systems that incorporate cyclodextrins to get materials for some specific applications.

Cyclodextrins (CDs) are a family of biodegradable cyclic hydrocarbons composed of α-(1,4) linked glucopyranose subunits, the more common containing 6, 7 or 8 glucose units are named α, β and γ-cyclodextrins respectively. Since the discovery of CDs, they have attracted interest among scientists and the first studies were about the properties of the native compounds and in particular their use as catalysts of organic reactions. Characteristics features of different types of cyclodextrins stimulated invest...

Influence of molecular structure on the susceptibility of starch to α-amylase.

The effect of the molecular structure of sweet potato (SPS), cassava (CAS) and high amylose maize (HAS) starches on the susceptibility to fungal and maltogenic α-amylases was investigated. The logarithm of the slope (LOS) and non-linear least-squares (NLLS) methods were used for fitting hydrolysis kinetics data. The malto-oligosaccharides released during hydrolysis were quantified and the hydrolysis residues were analyzed. The hydrolysis kinetic curves were well fitted to the LOS and NLLS models. SPS, CAS ...

Large-scale quantitative isolation of pure protein N-linked glycans.

Glycoproteins are biologically active proteins of which the attached glycans contribute to their biological functionality. Limited data is available on the functional properties of these N-glycans in isolation, without the protein core. Glycan release, typically performed with the PNGase F enzyme, is achieved on denatured proteins in the presence of detergents which are notoriously difficult to be completely removed. In this work we compared two methods aiming at recovering N-glycans in a high yield and at ...

Synthesis and characterization of α-d-Galp-(1 → 3)-β-d-Galp epitope-containing neoglycoconjugates for chagas disease serodiagnosis.

The immunodominant epitope α-d-Galp-(1 → 3)-β-d-Galp-(1 → 4)-d-GlcNAc, expressed in the mucins of the infective trypomastigote stage of Trypanosoma cruzi has been proposed for multiple clinical applications, from serodiagnosis of protozoan caused diseases to xenotransplantation or cancer vaccinology. It was previously shown that the analogue trisaccharide, with glucose in the reducing end instead of GlcNAc, was as efficient as the natural trisaccharide for recognition of chagasic antibodies. H...

Multivalent assembly of a pyrene functionalized thio-N-acetylglucosamine: Synthesis, spectroscopic and WGA binding studies.

We introduce here a new fluorescent derivative of 1-thio-β-N-acetylglucosamine linked to a pyrene system through a triazolylpentyl spacer, designed to self-assemble into a multivalent glycocluster. The synthesis was achieved by efficient CuAAC click reaction between a pyrene functionalized with an azide group and a suitable alkynyl thiomonosaccharide. Spectroscopic studies by fluorometry indicated that the self-assembly in aqueous medium is modulated by concentration and pH changes, the latter due to the p...

The K90 capsular polysaccharide produced by Acinetobacter baumannii LUH5553 contains di-N-acetylpseudaminic acid and is structurally related to the K7 polysaccharide from A. baumannii LUH5533.

Acinetobacter baumannii isolate LUH5553 carries the KL90 capsule gene cluster, which includes genes for three glycosyltransferases (Gtrs) and the ItrA3 initiating transferase, as well as a set of genes for synthesis of a higher sugar, 5,7-diacetamido-3,5,7,9-tetradeoxy-l-glycero-l-manno-non-2-ulosonic (di-N-acetylpseudaminic) acid (Pse5Ac7Ac). The K90 capsular polysaccharide (CPS) has a tetrasaccharide repeat (K90 unit), which begins with d-GlcpNAc and contains Pse5Ac7Ac. The higher sugar was cleaved by mil...

Synthesis of tricyclic quinazolinone-iminosugars as potential glycosidase inhibitors via a Mitsunobu reaction.

A series of novel tricyclic quinazolinone-iminosugars 1 (a-c) were synthesized from the benzyl protected sugars through three steps. Firstly, the benzyl protected sugar (aldehyde) 5 reacted with o-aminobenzamide by the iodine-induced oxidative condensation to afford the corresponding aldo-quizanolinone 6. Secondly, through the intramolecular cyclization of the unprotected OH and the amide NH in 6, the tricyclic compounds 7 and 8 were constructed by the key Mitsunobu reaction. Finally, removal of the benzyl ...

Glycosynthase-type GH18 mutant chitinases at the assisting catalytic residue for polymerization of chitooligosaccharides.

Chitooligosaccharides (COS), the depolymerization products of chitin, have many potential applications in agriculture and medicine since they induce immunostimulating effects and disease protective responses. Most of their biological activities require degrees of polymerization (DP) larger than the tetrasaccharide, but structurally well-defined COS with DP larger than six are difficult to produce due to their high insolubility and complex isolation from chitin hydrolysates. Enzymatic synthesis by exploiting...

Studies on the reversible enzyme reaction of rabbit muscle glycogen phosphorylase b using isothermal titration calorimetry.

Glycogen phosphorylase enzymes (GP) catalyse reversible reactions; the glucose transfer from glycogen to inorganic phosphate (P, phosphorolysis) or the reverse glucose transfer from glucose-1-phosphate (G-1-P) to glycogen (synthesis). Rabbit muscle GPb (rmGPb) was used as a model enzyme to study the reversible enzyme reaction. To follow both directions of this reversible reaction, we have developed a novel isothermal titration calorimetry (ITC) method for the determination of the direct reaction rate. The p...

Adhesive alginate for buccal delivery in aphthous stomatitis.

Recurrent aphthous stomatitis being the most common chronic disease of the oral cavity affects 5-25% of the population.

Synthesis of het(aryl) imidazole C-nucleoside analogues by CoFeO NPs catalyzed muti-component coupling reaction.

A general synthesis of hetaryl and aryl C-4(5) linked imidazole C-nucleoside analogues has been developed by the reaction of sugar alkynes with het(aryl) iodides, KMnO/TBAB oxidation and CoFeO NPs catalyzed muti-component coupling of the corresponding diketones, NHOAc and aromatic aldehydes in one-pot. The sugar alkynes include pyranosides and furanosides with acid sensitive protecting groups. The het(aryl) iodides comprise iodoaromatics, iodoheterocycles, and sterically hindered iodoheteroaromatics.

Stereoselective synthesis of substituted 1,2-annulated sugars by domino double-Michael addition reaction.

A simple, highly stereoselective one-pot methodology for the synthesis of novel 1,2-annulated sugars comprising of oxa-oxa and oxa-carbasugar fused skeletons from 2-nitrogalactal and a sugar-derived enone, obtained from 2-formylgalactal, promoted by KOBu and CHONa respectively is described. Both processes rely on a domino double-Michael addition reaction resulting in the formation of three stereocenters in a single pot, including a quaternary center.


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