Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “SACCHARIDES”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 181 records · Page 10Linked to original sources
PubMed1980

Inhibition by warfarin of prothrombin synthesis and of lipid-saccharide synthesis in rat liver.

In vivo and in vitro studies using [3H]glucosamine incorporation into prothrombin and into glycolipids were conducted in rat liver to determine the role of lipid-saccharides in the biosynthesis of prothrombin. In vivo studies demonstrated that 10 mg warfarin/kg inhibited the incorporation of radiolabeled glucosamine into liver prothrombin and glycolipids. This inhibition was similar to the kinetics of inhibition of prothrombin synthesis in the liver. In vitro studies demonstrated a time-dependent increase in the incorporation of radiolabeled glucosamine into lipid-saccharides and prothrombin. This incorporation was inhibited 50% by 5 . 10(-4) M warfarin. Warfarin also inhibited the incorporation of radiolabeled glucosamine into glycolipids in a dose-related manner. In all studies, vitamin K-1 reversed the inhibition of glucosamine incorporation into glycolipids and into prothrombin.

Animals↗
PubMed1990

Plant-derived sweetening agents: saccharide and polyol constituents of some sweet-tasting plants.

Samples of the sweet-tasting species Acanthospermum hispidum DC. (Compositae) (aerial parts), Boscia salicifolia Oliv. (Capparidaceae) (stem bark), Hovenia dulcis Thunb. (Rhamnaceae) (peduncles) and Inga spectabilis Willd. (Leguminosae) (arils) were acquired as part of a continuing search for high-intensity natural sweeteners of plant origin. Following their preliminary safety evaluation, the sweetness of these plants was traced to large amounts of sugars and polyols by taste-guided fractionation, which were identified and quantified using gas chromatography/mass spectrometry. The combined yields of sugars and polyols in the A. hispidum, B. salicifolia, H. dulcis, and I. spectabilis samples investigated were 6.9, 10.1, 18.4 and 12.1% w/w, respectively. These yields are much higher than the total saccharide and polyol content (2.4% w/w) of the sweet dried fruits of Thladiantha grosvenorii (Swingle) C. Jeffrey (Cucurbitaceae), a species which has previously been reported to contain more than 1% w/w of the intensely sweet triterpene, mogroside V. The dried leaves of Symplocos tinctoria (L.) L'Hérit. (Symplocaceae), which were not appreciably sweet, were found to contain only 2.0% w/w of sugars. The results of this investigation, therefore, suggest that unless the saccharide and/or polyol content of a plant part is well over 5% w/w, then it is unlikely to exhibit an overtly sweet taste, unless an intense sweetener is present.

Alcohols↗
PubMed1989

Left heart opacification with peripheral venous injection of a new saccharide echo contrast agent in dogs.

Opacification of the left heart chambers after venous injection of echo contrast agents with transpulmonary capabilities has been difficult to achieve because of a lack of availability of a biodegradable nontoxic agent that produces uniformly small microbubbles. SHU-508 is a new saccharide echo contrast agent that produces bubble sizes from 2 to 8 microns in diameter, capable of traversing the pulmonary capillary bed and resulting in left heart contrast. The echo intensity produced by this agent was compared with that of agitated saline solution, indocyanine green and SHU-454 (another experimental saccharide agent for right-sided contrast) during 136 injections in eight dogs. Videotaped two-dimensional echographic images were digitized and analyzed with the use of videodensitometry for peak right and left ventricular intensity, pulmonary transit times and time of persistence of contrast. The highest right ventricular intensity value (3,594 +/- 1,393) was achieved with SHU-508 (p less than 0.05 compared with the other agents). The right ventricular contrast seen with SHU-508 also persisted for a longer period (22.8 +/- 12 s) than with the standard agents (p less than 0.001). Left ventricular contrast with SHU-508 was visually evident in all 42 injections, whereas the peak left ventricular intensity was 35% as bright as that produced in the right ventricle by the same agent. Peak left ventricular intensity values from SHU-508 were compared with those from agitated saline solution injected from the pulmonary capillary wedge position in four dogs. SHU-508 produced brighter left ventricular intensity (1,281 +/- 607) compared with that obtained with the saline-wedge technique (p les than 0.002).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2004

Saccharides as efficacious solubilisers for highly lipophilic compounds in aqueous media.

The bioavailability of lipophilic substrates is critical for biotransformations with isolated enzymes as well as with whole cells. With the example of a series of lipophilic ketones the suitability of saccharides as potent solubilisers for highly lipophilic substrates was demonstrated. Best results were obtained for d-glucose, which increased substrate solubility up to 50 times. In whole-cell biocatalysis the sugar acts both as solubiliser and as carbon source for which reason this procedure does not impair cell physiology and is unique in being environmentally benign. The capability of saccharides to solubilise lipophilic compounds in aqueous media sources from their ability to form hydrophilic and lipophilic domains at hydrophobic interfaces, thus forming cyclodextrin-like structures around the lipophilic substrate.

Biotransformation↗
PubMed2004

Vacuum-ultraviolet circular dichroism study of saccharides by synchrotron radiation spectrophotometry.

Vacuum-ultraviolet circular dichroism (VUVCD) spectra of five monosaccharides (D-glucose, D-mannose, D-galactose, D-xylose, and D-lyxose) and five disaccharides (maltose, isomaltose, cellobiose, gentiobiose, and lactose) were measured to 160 nm using a synchrotron-radiation VUVCD spectrophotometer in aqueous solution under high vacuum at 25 degrees C. Most of the saccharides show a positive peak with some shoulders at around 170 nm, except for D-galactose and lactose, which show two distinct negative peaks at around 165 and 177 nm. These spectra are influenced by such structural factors as alpha and beta anomers at C-1, axial and equatorial hydroxyl groups at C-2 and C-4, trans (T) and gauche (G) conformations of the hydroxymethyl group at C-5, and the type of glycosidic linkage. Deconvolution of the VUVCD spectra of D-glucose, D-mannose, and D-galactose into six independent Gaussian components for alpha-GG, alpha-GT, alpha-TG, beta-GG, beta-GT, and beta-TG conformations suggests that the alpha anomer has red-shifted spectra relative to the beta anomer, and that GG and GT conformations have positive and negative circular dichroism signs, respectively, while the sign for TG conformation is anomer dependent. These speculations from the deconvolution analyses are also supported by the VUVCD spectra of disaccharides. These results give new insight into the equilibrium conformations of saccharides, demonstrating the usefulness of synchrotron-radiation VUVCD spectroscopy.

Carbohydrate Conformation↗
PubMed2006

Positive electrospray ion trap multistage mass spectrometric fragmentation of synthetic analogs of saccharide part of lipopolysaccharides of Vibrio cholerae O:1.

Oligosaccharides (mono- to hexamers) that mimic the terminal epitopes of O-antigens of Vibrio cholerae O:1, serotypes Ogawa and Inaba, have been studied by electrospray ion trap (ESI IT) mass spectrometry. Sodium or potassium-cationized adducts are characteristic ions under the conditions of ESI-MS analysis. The tentative pathways of fragmentation have been proven by multistage ion trap MS (MS(n), n = 1-3). The predominant pathway of fragmentation of the oligomers is the neutral loss of monosaccharide residue shortening the length of the oligosaccharide. In this way, conversion of the Ogawa to Inaba fragments takes place under the conditions of measurement. ESI MS/MS provided sufficient information about molecular mass, the number of saccharide residues, and the structure of saccharides, about the C (4)-amide of 3-deoxy-L-glycero-tetronic acid (DGT) of the compounds investigated, and allows to distinguish between Ogawa and Inaba serotypes.

Antigens, Bacterial↗
PubMed2003

Separation of saccharides derivatized with 2-aminobenzoic acid by capillary electrophoresis and their structural consideration by nuclear magnetic resonance.

Saccharides including mono- and disaccharides were quantitatively derivatized with 2-aminobenzoic acid (2-AA). These derivatives were then separated by capillary zone electrophoresis with UV detection using 50mM sodium phosphate buffer as the running electrolyte solution. In particular, the saccharide derivatives with the same molecular weight as 2-AA aldohexoses (mannose and glucose) and 2-AA aldopentoses (ribose and xylose) were well separated. The underlying reasons for separation were explored by studying their structural data using 1H and 13C NMR. It was found that the configurational difference between their hydroxyl group at C2 or C3 could cause the difference in Stokes' radii between their molecules and thus lead to different electrophoretic mobilities. The correlation between the electrophoretic behavior of these carbohydrate derivatives and their structures was studied utilizing the calculated molecular models of the 2-AA-labeled mannose, glucose, ribose, and xylose.

Electrophoresis, Capillary↗
PubMed2003

"Multivalent" saccharides: development of new approaches for inhibiting the effects of glycosphingolipid-binding pathogens.

A number of diseases are initiated by the adherence of viruses, bacteria, or bacterial toxins to cell surface carbohydrates, a number of which are components of glycosphingolipids (GSLs). Studies of the binding of lectins indicated that many adhered weakly to monomeric carbohydrate ligands. The seminal observation that lectins adhered more strongly to a ligand with multiple carbohydrate binding sites initiated a plethora of studies designed to identify effective "multivalent" carbohydrate ligands for pathogens expressing multiple carbohydrate-binding sites. In addition to more completely defining ligand specificity of the carbohydrate-binding pathogen, identification of "multivalent" carbohydrate ligands has led to studies of their efficacy as pathogen inhibitors. This commentary focuses on pathogens that recognize the carbohydrate portion of GSLs. Because many GSL-binding pathogens have been shown to bind "multivalent" saccharides, approaches for identifying and preparing them as well as methods for characterizing their effectiveness as ligands are reviewed. Also discussed are areas of promise that should be investigated and pitfalls that might be encountered in the development of "multivalent" saccharides as pharmacologic agents.

Animals↗
PubMed2000

Synthesis of the Lewis b hexasaccharide and squarate acid-HSA conjugates thereof with various saccharide loadings.

The Lewis b hexasaccharide, alpha-L-Fucp-(1 --> 2)-beta-D-Galp-(1 --> 3)-[alpha-L-Fucp-(1 --> 4)]-beta-D-GlcpNAc-(1 --> 3)-beta-D-Galp-(l --> 4)-beta-D-Glcp, has been synthesised using a convergent synthesis. Starting from ethyl 4,6-O-benzylidene-2-deoxy-2-phthalimido-1-thio-beta-D-glucopyranoside, a thioglycoside tetrasaccharide donor block, was constructed through two orthogonal glycosylations with glycosyl bromide donors. First, the galactose moiety was introduced using silver triflate as a promoter and then the two fucose residues under halide-assisted conditions. Finally, this tetrasaccharide was linked to a spacer-equipped 3I,4I-diol lactose acceptor in a DMTST-promoted coupling to give, after deprotection, the Lewis b hexasaccharide as its 2-aminoethyl spacer-equipped derivative. This was coupled to human serum albumin (HSA), using the squarate ester methodology, in various saccharide-protein ratios, to give neoglycoconjugates with different saccharide loadings in about 50%) efficiency.

Carbohydrate Conformation↗
PubMed1981

Depolymerization of glycosaminoglycuronans into di- and higher molecular-weight oligo-saccharides: improved preparation of N-acetyldermosine and oligomeric N-acetylchondrosines.

Nonsulfated di- to octadeca-saccharides having 2-acetamido-2-deoxy-D-galactose at the reducing end were prepared, in 81% yield, by treatment of chondroitin 6-sulfate (pyridinium salt) with dimethyl sulfoxide containing 10% of water for 14 h at 90 degrees. N-Acetylchondrosine and N-acetyldermosine were obtained from dermatan sulfate of rooster comb, in 30% and 38% yields, respectively, by solvolysis with dimethyl sulfoxide, containing 10% of water, for 30 h at 105 degrees. Hyaluronic acid was also depolymerized by the same solvent in the presence of an equimolar amount of pyridinium sulfate or chloride per disaccharide unit to give reducing di- and higher molecular weight oligo-saccharides. The results of solvolytic desulfation and depolymerization are compared with those of the conventional methods by acid hydrolysis.

Animals↗
PubMed2000

Effects of various saccharides on cycloinulo-oligosaccharide fructanotransferase reaction: production of beta-inulotriosyl-alpha-D-mannopyranoside and 1-O-beta-inulotriosyl-alpha-L-sorbopyranose.

The effects of various saccharides on the reaction of cycloinulo-oligosaccharide fructanotransferase with cycloinu-lohexaose were examined. In addition to beta-D-fructofuranosides and methyl alpha-D-glucopyranoside, D-mannose and L-sorbose were found to be effective acceptors in the reactions, and they enhanced the hydrolytic activity as effectively as methyl alpha-D-glucopyranoside. Hetero-tetrasaccharides were isolated as the major transfer products from both reaction mixtures. The isolates were identified by NMR spectroscopy as beta-inulotriosyl-alpha-D-mannopyranoside and 1-O-beta-inulotriosyl-alpha-L-sorbopyranose. Methyl beta-D-glucopyranoside was slightly effective and methyl alpha-D-mannopyranoside was not effective at all as the acceptor, but these saccharides strongly enhanced the hydrolytic activity. D-Glucosamine inhibited the enzyme activity.

Carbohydrate Sequence↗
PubMed2000

Enhancing effect of saccharides on the mutagenicity of 2-chloro-4-methylthiobutanoic acid.

The mutagenicity of 2-chloro-4-methylthiobutanoic acid (CMBA), a nitrite-treated Sanma fish mutagen, in Salmonella typhimurium TA100 was enhanced by addition of D-glucose during the CMBA-treatment. Several other monosaccharides also enhanced the mutagenicity of CMBA, and the order of the enhancing potency was found to be D-mannose, D-glucose>D-fructose, D-ribose, D-galactose. A disaccharide, maltose, showed only little enhancement. No enhancement was found with L-glucose. We investigated whether saccharides affect uptake of [methyl-14C]CMBA into S. typhimurium TA100. Saccharides which enhanced CMBA-induced mutagenesis increased the uptake. L-Glucose did not enhance the uptake. There was good correlation between the enhanced mutagenesis and increased radioactivity in Salmonella, suggesting that the enhancing effect of monosaccharide on the CMBA-induced mutagenesis results from the enhanced uptake of the mutagen into bacteria.

Butyrates↗
PubMed1998

Serum antibody responses of weanling mice and two-year-old children to pneumococcal-type 6A-protein conjugate vaccines of differing saccharide chain lengths.

Type 6A pneumococcal polysaccharide (PS) fractions having mean lengths 2, 7, or 14 repeat units were coupled to tetanus toxoid, giving conjugates T-6A-2, T-6A-7 or T-6A-14. In weanling outbred mice, type-6A serum antibody responses were minimal to T-6A-7 but significantly higher to T-6A-2 and T-6A-14. In contrast, two-year-old humans responded increasingly to T-6A-2, T-6A-7, and T-6A-14; type 6B antibody rose, but variably. Upon challenge with 6B PS at age 3 yr, conjugate-primed children made anamnestic responses. T-6A-14, containing the longest saccharide chains (and highest saccharide:protein mass ratio) excelled in priming as well as antibody induction.

Adult↗
PubMed1996

PapG adhesin from E. coli J96 recognizes the same saccharide epitope when present on whole bacteria and as isolated protein.

Purified PapG adhesin from the genetically well-defined uropathogenic Escherichia coli strain J96, as well as whole bacteria, were bound to microtiter plates that carried covalently bound globotetraose and galabiose. The binding was inhibited by soluble saccharide derivatives corresponding to the glycolipids, including all di-, tri-, tetra-, and pentasaccharide fragments of the Forssman antigen and all monodeoxy analogues of galabiose. Analysis of the inhibition pattern showed no significant difference between purified adhesin and whole bacteria. The glucose unit at the reducing end of the natural saccharides was detrimental to PapG binding since deletion of the glucose unit increased the inhibitory power 10-20 fold. The five hydroxyl groups HO-6, -2', -3', -4', -6' of the galabiose unit were shown to be important for PapG binding, presumably via intermolecular hydrogen bonds.

Adhesins, Escherichia coli↗
PubMed1997

Saccharide-RNA recognition in an aminoglycoside antibiotic-RNA aptamer complex.

BACKGROUND: Aminoglycoside antibiotics are known to target ribosomal, retroviral and catalytic RNAs with high affinity and specificity. Recently, in vitro selection experiments have identified RNA aptamers that bind to aminoglycoside antibiotics with nanomolar affinity and stringent specificity, allowing discrimination between closely related family members. There has, to date, been limited structural information on the molecular basis of such saccharide-RNA recognition. RESULTS: We describe a solution-structure determination of the tobramycin-RNA aptamer complex, obtained using NMR and molecular dynamics. The structure gives insight into the molecular features associated with saccharide-RNA recognition. Tobramycin adopts a defined alignment and binds to the RNA major groove centered about a stem-loop junction site. A portion of the bound tobramycin is encapsulated between the floor of the major groove and a looped-out cytosine residue that forms a flap over the binding site in the complex. CONCLUSIONS: The emergence of antibiotic-resistant pathogens and their impact on human health continues to be a major concern in the medical community. Rational modification of existing antibiotics aimed at improving their efficacy requires a molecular view of their receptor-binding sites. We have provided such a molecular view for a member of the aminoglycoside antibiotic family that targets RNA.

Anti-Bacterial Agents↗
PubMed2002

Detection and identification of aqueous saccharides by using surface-enhanced Raman spectroscopy.

The sensitive detection and characterization of carbohydrates by means of a strategy based on surface-enhanced Raman spectroscopy is demonstrated. Spectra are obtained after injecting a small amount of saccharide solution onto a roughened silver substrate, with subsequent deposition of silver colloid. The sensitivity achieved by this two-step approach enables high-quality Raman spectra to be obtained for small amounts of aqueous saccharides (5 microL of a 10(-2) M solution) utilizing minimal laser power and small signal acquisition times (a few seconds). Spectral "fingerprints" obtained for seven structurally similar monosaccharides demonstrate clearly an effective means by which each sugar can be identified. The application to more complex analyses is demonstrated for monosaccharide mixtures and a disaccharide, whereby the SERS fingerprints aid in the determination of components.

Carbohydrates↗
PubMed1991

Comparison of the effects of saccharide binding and crystallization on the zinc transition-metal site of concanavalin A.

The Zn site in concanavalin A solution was studied by X-ray absorption fine structure spectroscopy (XAFS) with and without the saccharide methyl alpha-D-glucoside (aMG) bound to the protein. No structural change occurs in the metal-binding site when the saccharide is bound to the protein. There is, however, evidence for structural change remote from the metal site. This is in contrast to the significant changes that we have previously found to occur in the near neighborhood of the Zn atom when an aqueous solution of Zn concanavalin A crystallizes. We propose a structural explanation of these facts based on the known crystal structure of concanavalin A.

Concanavalin A↗
PubMed1978

Saccharide binding to transition metal ion free concanavalin A.

Saccharide binding has been observed with demetallized concanavalin A in the presence of Ca(2+) only, using the fluorescent sugar 4-methylumbelliferyl alpha-D-mannopyranoside. At pH 7.2 both the nicked and intact forms of concanavalin A bound 4-methylumbelliferyl alpha-D-mannopyranoside with similar affinities. Competitive binding with methyl alpha-D-mannopyranoside was demonstrated. The association constants at 5 degrees C were 9.6 +/- 0.6 X 10(4) M(-1) for 4-methylumbelliferyl alpha-D-mannopyranoside and 1.1 +/- 0.3 X 10(4) M(-1) for methyl alpha-D-mannopyranoside. 4-Methylumbelliferyl alpha-D-mannopyranoside binding was also observed if demetallized concanavalin A was remetallized with less than stoichiometric amounts of Ca(2+). The association constants with low Ca(2+) concentrations were similar to those determined with saturating Ca(2+). With less than stoichiometric levels of Ca(2+), the number of sugar molecules bound per protein subunit was a reflection of the fraction of activated lectin subunits. These results show that saccharide binding activity of concanavalin A does not require a transition metal ion at pH 7.2; only Ca(2+) is required. At pH values near 5, where most previous studies have been carried out, both a transition metal ion and Ca(2+) are necessary.

Binding, Competitive↗