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PubMed1999

Gas-liquid chromatography of the heptafluorobutyrate derivatives of the O-methyl-glycosides on capillary columns: a method for the quantitative determination of the monosaccharide composition of glycoproteins and glycolipids.

We have developed a method involving the formation of hepta-fluorobutyrate derivatives of O-methyl-glycosides liberated from glycoproteins and glycolipids following methanolysis. The stable derivatives of the most common monosaccharides of these glycoconjugates (Ara, Rha, Xyl, Fuc, Gal, Man, Glc, GlcNAc, GalNAc, Neu5Ac, KDN) can be separated and quantitatively and reproducibly determined with a high degree of sensitivity level (down to 25 pmol) in the presence of lysine as an internal standard. The GlcNAc residue bound to Asn in N-glycans is quantitatively recovered as two peaks. The latter were easily distinguished from the other GlcNAc residues of N-glycans, thus allowing a considerable improvement of the data on structure of N-glycans obtained from a single carbohydrate analysis. The most common contaminants present in buffers commonly used for the isolation of soluble or membrane-bound glycoproteins (SDS, Triton X-100, DOC, TRIS, glycine, and polyacrylamide or salts, as well as monosaccharide constituents of proteoglycans or degradation products of nucleic acids) do not interfere with these determinations. A carbohydrate analysis of glycoproteins isolated from a SDS/PAGE gel or from PDVF membranes can be performed on microgram amounts without significant interferences. Since fatty acid methyl esters and sphingosine derivatives are separated from the monosaccharide peaks, the complete composition of gangliosides can be achieved in a single step starting from less than 1 microg of the initial compound purified by preparative Silicagel TLC. Using electron impact ionization mass spectrometry, reporter ions for the different classes of O-methyl-glycosides (pentoses, deoxy-hexoses, hexoses, hexosamines, uronic acids, sialic acid, and KDN) allow the identification of these compounds in very complex mixtures. The mass of each compound can be determined in the chemical ionization mode and detection of positive or negative ions. This method presents a considerable improvement compared to those using TMS derivatives. Indeed the heptafluorobutyrate derivatives are stable, and acylation of amino groups is complete. Moreover, there is no interference with contaminants and the separation between fatty acid methyl-esters and O-methyl glycosides is achieved.

Acylation↗

PubMed1992

Intestinal amino acid and monosaccharide transport in suckling pigs fed milk replacers with different sources of carbohydrate.

Omnivorous mammals are able to adaptively modulate rates of intestinal nutrient transport to match changes in diet. Because adaptive responses during suckling, when dietary composition is relatively constant, have not been adequately determined, we measured in vitro sugar and amino acid uptake [nmol/(mg tissue.min)] in suckling pigs fed milk replacers with either lactose (LAC) or a 60:40 mixture of maltodextrin and sucrose (MDS). The MDS-fed pigs initially grew slower, but had intestinal dimensions similar to those of LAC-fed siblings when normalized to body weight. Carrier-mediated uptake for three monosaccharides (glucose, galactose, fructose) did not differ between LAC- and MDS-fed pigs at 5, 10, 15 and 20 d of age. Interdiet differences in rates of leucine and proline uptake, despite identical types and concentration of protein in both milk replacers, are indicative of non-specific responses to diet during suckling. Uptake capacities (grams of monosaccharide absorbed per 24 h) never exceeded estimates of monosaccharide intake by more than fourfold and were less than aldohexose intake during early suckling. Our results indicate 1) age-related changes in rates of nutrient uptake are genetically programmed and little influenced by diet; 2) any responses to diet are nonspecific and likely involve a shift in the timing of the genetic program; and 3) at birth and throughout suckling, pigs are capable of absorbing limited quantities of alternative nutrients.

Aging↗

PubMed2002

Common origin and evolution of glycosyltransferases using Dol-P-monosaccharides as donor substrate.

On the basis of the analysis of 64 glycosyltransferases from 14 species we propose that several successive duplications of a common ancestral gene, followed by divergent evolution, have generated the mannosyltransferases and the glucosyltransferases involved in asparagine-linked glycosylation (ALG) and phosphatidyl-inositol glycan anchor (PIG or GPI), which use lipid-related donor and acceptor substrates. Long and short conserved peptide motifs were found in all enzymes. Conserved and identical amino acid positions were found for the alpha 2/6- and the alpha 3/4-mannosyltransferases and for the alpha 2/3-glucosyltransferases, suggesting unique ancestors for these three superfamilies. The three members of the alpha 2-mannosyltransferase family (ALG9, PIG-B, and SMP3) and the two members of the alpha 3-glucosyltransferase family (ALG6 and ALG8) shared 11 and 30 identical amino acid positions, respectively, suggesting that these enzymes have also originated by duplication and divergent evolution. This model predicts a common genetic origin for ALG and PIG enzymes using dolichyl-phospho-monosaccharide (Dol-P-monosaccharide) donors, which might be related to similar spatial orientation of the hydroxyl acceptors. On the basis of the multiple sequence analysis and the prediction of transmembrane topology we propose that the endoplasmic reticulum glycosyltransferases using Dol-P-monosaccharides as donor substrate have a multispan transmembrane topology with a first large luminal conserved loop containing the long motif and a small cytosolic conserved loop containing the short motif, different from the classical type II glycosyltransferases, which are anchored in the Golgi by a single transmembrane domain.

Amino Acid Motifs↗

PubMed2003

Functional characterization and expression analyses of the glucose-specific AtSTP9 monosaccharide transporter in pollen of Arabidopsis.

A genomic clone and the corresponding cDNA of a new Arabidopsis monosaccharide transporter AtSTP9 were isolated. Transport analysis of the expressed protein in yeast showed that AtSTP9 is an energy-dependent, uncoupler-sensitive, high-affinity monosaccharide transporter with a K(m) for glucose in the micromolar range. In contrast to all previously characterized monosaccharide transporters, AtSTP9 shows an unusual specificity for glucose. Reverse transcriptase-polymerase chain reaction analyses revealed that AtSTP9 is exclusively expressed in flowers, and a more detailed approach using AtSTP9 promoter/reporter plants clearly showed that AtSTP9 expression is restricted to the male gametophyte. AtSTP9 expression is not found in other floral organs or vegetative tissues. Further localization on the cellular level using a specific antibody revealed that in contrast to the early accumulation of AtSTP9 transcripts in young pollen, the AtSTP9 protein is only found weakly in mature pollen but is most prominent in germinating pollen tubes. This preloading of pollen with mRNAs has been described for genes that are essential for pollen germination and/or pollen tube growth. The pollen-specific expression found for AtSTP9 is also observed for other sugar transporters and indicates that pollen development and germination require a highly regulated supply of sugars.

Amino Acid Sequence↗

PubMed1995

Subcellular localization of the inducible Chlorella HUP1 monosaccharide-H+ symporter and cloning of a Co-induced galactose-H+ symporter.

The unicellular green alga Chlorella kessleri can induce monosaccharide-H+ symport catalyzing the energy-dependent transport of D-glucose (D-Glc) and several other pentoses and hexoses across the plasmalemma. The gene coding for the inducible HUP1 monosaccharide-H+ symporter has been cloned and the protein has been characterized previously. The data presented in this paper demonstrate that the presence of the HUP1 gene product alone is not sufficient to cover the broad substrate specificity of monosaccharide transport in induced Chlorella cells. Two other HUP genes are shown to be co-induced in Chlorella in response to D-Glc in the medium. The cloning of HUP2 and HUP3 cDNA and genomic sequences is described, both being very homologous to HUP1. Modification of the 5' untranslated sequences of full-length cDNA clones of HUP2 and HUP3 allowed the functional expression of both transporters in Schizosaccharomyces pombe. HUP2 was shown to be a galactose-H+ symporter, whereas the substrate specificity of the HUP3 gene product is very similar to that of the HUP1 protein. However, HUP3 does not seem to be induced to high levels in Glc-treated Chlorella cells. Results are also presented proving that the product of the HUP1 gene is localized in the plasmalemma of D-Glc-induced Chlorella cells and is absent in plasma membranes of noninduced cells. Incubation of thin sections of Chlorella cells with anti-HUP1 antibodies and a fluorescence-labeled, second antibody yielded a ring of fluorescence on the surface of Glc-induced Chlorella cells.

Base Sequence↗

PubMed1976

Cellular monosaccharide patterns of Neisseriaceae.

Sixty-four strains of Neisseria, Moraxella, and Acinetobacter were screened for cellular monosaccharides by gas-liquid chromatography and other chromatographic techniques. The four sugars ribose, glucose, glucosamine, and 2-keto-3-deoxyoctonate (KDO) were detected in all strains. Heptose was detected only in "true neisseriae" (Neisseria gonorrhoeae, N. meningitidis, N. sicca, N. cinerea, N. flavescens, and N. elongata) and in the tentaively named species Moraxella urethralis. Some marked interspecies dissimilarities within groups were revealed. Thus, N. ovis and M. atlantae were characterized by the presence of mannose. Intraspecies differences were also encountered. N. meningitidis strains of serogroups B and C were distinguished from strains of serogroup A by their sialic acid content. This sugar was also detected in two out of three examined strains of M. nonliquefaciens. In Acinetobacter, heterogeneity of monosaccharide patterns was rather pronounced. The results show the applicability of gas chromatographic "monosaccharide" profiles fo whole cells or extracted carbohydrate in bacterial classification and identification, including differentiation at the subspecies level. In addition, such profiles may be useful for monitoring during purification of cellular polysaccharides.

Acinetobacter↗

PubMed1989

Biocompatibility of wound management products: the effect of various monosaccharides on L929 and 2002 fibroblast cells in culture.

The effects of various monosaccharides on the growth of human 2002 and mouse L929 fibroblast cultures have been investigated. Eleven monosaccharides having acidic, neutral, and basic characteristics were evaluated in a bioassay procedure developed for the investigation of biocompatibility of wound management materials. Rate of growth in both cell lines was inhibited by D-galacturonic acid and by D-glucuronic acid. Although most neutral sugars produced no significant change in the growth rate or in the morphology of the cells, galactose produced a significant increase in the growth rate of both cell lines whilst L-fucose caused a significant decrease in growth of the L929 cells but did not significantly affect the growth of 2002 cells; xylose increased the growth rate of L929 but not 2002 cells. D-Glucosamine, a basic sugar, produced inhibition of growth which followed a different pattern from that produced by the acidic sugars; N-acetylglucosamine produced a species specific increase in cell growth of L929 cells. The results show that the effects produced by the monosaccharides on the cultured fibroblasts are related to their chemical structure and to cell line, and suggest that the use of galactose as a possible aid to wound healing should be investigated.

Animals↗

PubMed1984

Monosaccharide transport by the small intestine of lean and genetically obese (ob/ob) mice.

The effect of the obese (ob/ob) genotype on monosaccharide transport in mouse small intestine has been examined, using several different methodologies, at various stages in the development of the syndrome. Evidence for an elevation of the total capacity of the small intestine for monosaccharide transport was found at 10, 20 and 40 weeks of age in obese mice by comparison with lean controls, the difference being most prominent at 20 weeks of age after the hyperphagic phase of the syndrome had ceased. No substantial alteration in transport, expressed per gram dry weight of intestine, either from luminal perfusion studies or from measurements of the kinetics of influx across the brush border was found in adult obese mice compared with lean controls. It is concluded that, in obese mice, the increased capacity of the intestine for monosaccharide transport compared with lean mice was due to increases in the total intestinal dry weight, and in the intestinal dry weight per centimetre, and not to changes in carrier activity per unit dry weight of intestine.

Age Factors↗

PubMed1986

Interactions between monosaccharides and disaccharides during uptake by the perfused liver of rat.

The extractions of D-glucose, L-glucose, D-fructose and D-galactose by the isolated liver of rat perfused at constant flow were estimated by paired tracer dilution. The effects on these of 25 mM concentrations of these monosaccharides, of alpha-methyl-glucoside and of the disaccharides sucrose, maltose, and lactose were measured. Inferences were drawn from these data about the transport of monosaccharides at the sinusoidal surface of the liver cells. The hepatic clearances of the isomeric monosaccharides consistently ranked D-glucose (at 5.5 X 10(-3) M) greater than D-galactose (2.5 X 10(-5) M) greater than D-fructose (3.2 X 10(-7) M) much greater than L-glucose (2 X 10(-6) M). This implies at least that there are membrane transport mechanisms with distinctly lower affinity for the other sugars than for D-glucose. Glucose entry was stereoselective, and interactions amongst some of the sugars were demonstrated. A reproducible pattern of differential inhibition of D-glucose entry by the competing sugars at 25 mM was found. The consistent lack of effect of sucrose excluded a mere osmotic effect. The pattern of inhibition of D-fructose entry by the same sugars was qualitatively similar to that of D-glucose, whereas that of D-galactose was distinctive. The disaccharide competitors, lacking cell entry, can exert their effects only at the external surface. These markedly discriminate between D-glucose and D-galactose. The penetrating sugars, however, show mutual competition.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1987

Gas chromatography analysis of cellular fatty acids and neutral monosaccharides in the identification of lactobacilli.

Cellular fatty acids and monosaccharides in a group of 14 lactobacilli were analyzed by gas chromatography and the identity of the components was confirmed by gas chromatography-mass spectrometry. From the same bacterial sample, both monosaccharides and fatty acids were liberated by methanolysis, and in certain experiments, fatty acids alone were released by basic hydrolysis. The results indicate that basic hydrolysis gave more comprehensive information about the fatty acids, but the analysis of monosaccharides was found to be much more useful in distinguishing between different species of lactobacilli. The method described allowed differentiation of 11 of 14 Lactobacillus species, and even single colonies isolated from agar plates could be used for analysis without subculturing.

Chromatography, Gas↗

PubMed1975

Sensitivity of a Bacteroides melaninogenicus strain to monosaccharides: effect on enzyme induction.

The inhibition of growth in Bacteroides melaninogenicus by sugars in described. Monosaccharides such as D-glucose, D-galactose, D-mannose, and D-fructose are inhibitory at low concentrations, whereas the disaccharides sucrose and lactose are not inhibitory even at high concentrations. The major inhibitory effect of the sugar is found during the transition of lag to logarithmic growth phases. There was no primary effect of D-glucose on protein, ribonucleic acid, or deoxyribonucleic acid synthesis on cells in transition from lag to logarithmic growth. However, the addition of glucose or galactose completely abolished the induction of 3-ketodihydrosphingosine synthetase by vitamin K in vitamin K-depleted cells. Futhermore, in cells which were not vitamin K depleted, the level of this enzyme was drastically reduced by the addition of the sugar. Cyclic adenosine 5-monophosphate was unable to reverse the growth inhibition produced by glucose. In actively growing cultures, addition of sugar slows the growth rate. In these experiments the level of 3-ketodihydrosphingosine synthetase fell only after the cells had assumed the slower rate of growth. There were two indications that D-galactose was more inhibitory than D-glucose; in the presence of 0.1% D-galactose cells in lag phase did not show the increase in turbidity found in similar cells placed in medium with 0.1% D-glucose, and also D-galactose caused a greater decrease in the growth rate of actively growing cultures than was found with D-glucose. These studies suggest that the inhibitory effect of monosaccharides in lag leads to logarithmic growth transition can be ascribed to an effect on enzyme induction. On the other hand, the ability of many monosaccharides to inhibit growth, and the greater inhibitory property of D-galactose compared with D-glucose, suggests that other mechanisms may be operative as well.

Bacterial Proteins↗

PubMed1983

Monosaccharide absorption and water secretion during disaccharide perfusion of the human jejunum.

During jejunal perfusion of normal subjects with isotonic mannitol-saline containing glucose, maltose or sucrose (112 mmol/l), monosaccharide absorption from disaccharides was greater than expected from the intraluminal concentration of free monosaccharides, and water secretion was greater than with glucose. With equimolar (112 mmol/l) glucose + disaccharide mixtures, intraluminal glucose concentrations were similar to but total glucose absorption less than expected from experiments with the individual sugars. The results favour sequential hydrolysis-absorption whereby high concentrations of monosaccharide accumulate at the brush border and promote sugar uptake by conventional rather than 'disaccharidase-related' transport, and stimulate water secretion by local osmotic effects.

Adolescent↗

PubMed1993

Phagocytosis of monosaccharide-binding latex particles by guinea-pig polymorphonuclear leucocytes.

Phagocytosis of monosaccharide-binding latex particles by guinea-pig polymorphonuclear leucocytes (PMNs) was investigated. When neuraminic acid or glucuronic acid was chemically bound to the surface of latex particles the degree of phagocytosis was somewhat lower than that for bare, glucose-, mannose- or rhamnose-binding latex particles. These experimental findings were interpreted in terms of the kind of monosaccharide and the surface potential and surface hydrophobicity of latex particles. As a result, it was concluded that the inhibitory action of neuraminic acid or glucuronic acid on phagocytosis arises from an increase in the surface hydrophilicity of latex particles brought about by the hydroxyl groups and negative charges on the chemically bound neuraminic acid or glucuronic acid molecules. Physically adsorbed glucuronic acid molecules were also found to decrease the degree of phagocytosis of latex particles by PMNs, though not so remarkable as the chemically bound monosaccharide molecules.

Animals↗

PubMed2005

Interactions of single-walled carbon nanotubes with monosaccharides.

Closed-end single-walled carbon nanotubes were wetted in aqueous solutions of monosaccharides, forming weak surface complexes, as proven by the estimation of the content of monosaccharides in complexes isolated from aqueous solutions. The complexation was confirmed by micro-Raman spectroscopy. The Gaussian 03 (Molecular Mechanics UFF method) computations of total energy of the single-walled carbon nanotube-monosaccharides inclusion and surface complexes showed that inclusion complexes should be more stable than corresponding surface complexes. Computed total energies for particular complexes pointed to a lack of preferences for the formation of complexes with either alpha- or beta-tautomers and either pyranoses or furanoses. The forms preferred in the formation of the surface complexes usually differ from these favored in the formation of the inclusion complexes.

Binding Sites↗

PubMed1988

Effects of alkaline hydrogen peroxide treatment of cotton and wheat straw on cellulose crystallinity and on composition and site and extent of disappearance of wheat straw cell wall phenolics and monosaccharides by sheep.

Effects of alkaline hydrogen peroxide (AHP) treatment on cellulose crystallinity and cell wall phenolic monomer and monosaccharide composition were measured using cotton and wheat straw (WS). Two WS treatments were used in this study, Type I WS, for which pH is not regulated during AHP treatment, and Type II WS, for which pH is regulated at 11.5 +/- .2 during AHP treatment. Wheat straw had a lower degree of cellulose crystallinity than cotton, but no differences occurred between treated and untreated substrates. Alkali-labile and nitrobenzene-extractable phenolic monomer concentrations were generally lower for Type I and Type II WS compared with untreated WS. Concentrations of glucose were higher and xylose and arabinose lower in Types I and II WS than in untreated WS. Disappearance of alkali-labile phenolic monomers and cell wall monosaccharides by wethers fed diets containing Type I (Exp. 1) or Type II (Exp. 2) AHP-treated WS were determined. Apparent digestibility of glucose and xylose before the duodenum, and of glucose, xylose and arabinose in the total tract, was greatest (P less than .05) when sheep were fed AHP-treated WS diets in both experiments. In Exp. 2, disappearance of alkali-labile phenolic monomers was greatest (P less than .05) before the duodenum and in the total tract when sheep were fed AHP-treated WS diets. Treatment of WS with AHP modified cell wall composition and increased cell wall monosaccharide digestion by sheep.

Animal Feed↗

PubMedDate not supplied

[Structure-activity relationship of a new family of calcium antagonist molecules derived from monosaccharides].

The Ca++ antagonist effects of new drugs derived from monosaccharides were tested in the rat duodenal muscle preparation in vitro. The structure-activity relationship shows that: 1. The monoacetonide products (nR-O-MAG and nR-S-MAG) with alkyl chain from 8 to 9 C atoms induce a maximal reduction of muscular tonus and contraction. 2. The inhibitory effect rapidly decreases when the alkyl chain has a number of C atoms smaller than 7 or larger than 9. 3. The diacetonide (DAG) and acetonide (G) products induce an inhibition of less extent. 4. The Ca++ antagonist effect is very slightly changed by the type of heteroatom (O or S) linking the alkyl chain to the monosaccharide. 5. The type of monosaccharide affects the Ca++ antagonist activity.

Animals↗

PubMed1989

Disappearance of hemicellulosic monosaccharides and alkali-soluble phenolic compounds of normal and brown midrib sorghum x sudangrasses fed to heifers and sheep.

Eight yearling Holstein heifers (330 kg) were utilized in two 4 x 4 Latin squares. Diets were normal and brown midrib genotypes of Redlan x Greenleaf and Redlan x Piper varieties of ensiled first-cutting sorghum-sudangrass harvested at early head stage of maturity. Composition of hemicellulosic monosaccharides and alkali-soluble lignin phenolic compounds in feeds and corresponding digestibilities were estimated. Arabinose, xylose, and uronic acids were more digestible in brown midrib genotypes than in normal genotypes. p-Coumaric acid disappearance was higher in heifers consuming normal genotypes than in those on brown midrib mutants. In a second experiment, four Suffolk wethers with ruminal, duodenal, and ileal cannulae were utilized in a 4 x 4 Latin square design. Diets were second-cutting sorghum-sudangrass harvested at prehead stage of maturity as baled hay. Digestibilities were determined in the same manner as for heifers. Brown midrib genotypes had higher hemicellulosic monosaccharides, galactose, and uronic acids than did normal genotypes. Xylose content of the brown midrib mutant of Redlan x Piper was higher than that of the corresponding normal genotype. Total tract galactose digestibility was higher in brown midrib genotypes than in normal genotypes. Total tract hemicellulose digestibility (estimated by summing fractional digestibilities of hemicellulosic monosaccharides) was higher in brown midrib mutants than in normal genotypes.

Animal Feed↗

PubMed1989

Disappearance of hemicellulosic monosaccharides and alkali-soluble phenolic compounds of normal and brown midrib sorghum x sundangrass silages fed to Holstein steers.

Four ruminally cannulated Holstein steers fed ad libitum were used in a 4 x 4 Latin square design. Feeds were normal and brown midrib genotypes of Redlan x Piper and Redlan x Greenleaf sorghum-sudangrasses. An in situ trial was run in conjunction with the digestibility trial as part of the data collection for each period. Hemicellulosic monosaccharide and alkali-soluble lignin phenolic compound disappearances were quantitated. The xylose to arabinose ratio was higher in normal genotypes than in brown midribs. Normal genotypes had higher concentrations of alkali-soluble p-coumaric acid and lower vanillin, vanillic acid, and sinapic acid than did brown midrib mutants. Disappearance of p-coumaric acid was higher in steers consuming normal genotypes than in those consuming brown midribs. Neutral detergent fiber, acid detergent fiber, hemicellulose, cellulose, and acid detergent lignin showed no genotypic differences in rate of digestion, but extent of 72 h digestion was higher for brown midrib mutants than for normal genotypes. Extent of digestion of the hemicellulosic monosaccharides, xylose, and uronic acids was higher in situ for brown midrib silages compared with normal genotypes. Differences in alkali-soluble phenolic compound and cell wall monosaccharide profiles between normal and brown midrib genotypes may help explain digestibility differences between the two genotypes.

Animal Feed↗