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PubMed2003

Analysis of microfouling products formed on metallic surfaces exposed in a marine environment.

Mild steel (MS), stainless steel (SS) and copper (Cu) test panels were immersed in the surface water of Dona Paula Bay over a period of 15 d. During the immersion period data on the hydrography, nutrients and suspended matter were also collected. The suspended matter and fouling products on the MS, SS and Cu panels were analysed for organic carbon (OC), organic nitrogen (ON), chlorophyll a (chl a), protein and carbohydrate concentration and composition, and the dry weight (DW) was recorded. Compared to suspended matter, the chemical and biochemical components of the fouling products showed strong temporal and substratum related differences. The microfouling biomass (as DW, OC, ON, chl a and protein) on all the test panels generally increased over the period of immersion. Carbohydrates were more abundant in the suspended matter whereas fouling products were enriched in proteins. The contribution of protein-carbon to the total carbon increased over the period of immersion for the microfouling products on MS and SS whilst it did not show a consistent trend on Cu. Whereas, the carbohydrate-carbon contribution to the total carbon increased for the fouling products on MS, it did not exhibit a particular pattern on SS or Cu over the period of immersion. Capillary gas chromatographic analysis showed the presence of glucose, galactose, mannose, arabinose, xylose fucose and ribose in both the fouling products and suspended matter. However, there were differences in the relative distribution of these monosaccharides in the suspended matter and the fouling products. Glucose was the most abundant monosaccharide, which showed strong temporal variations in suspended matter. In contrast, the wt % concentrations of individual monosaccharides showed large temporal differences for the fouling products, which were strongly influenced by the period of immersion and the type of test substratum. Glucose and fucose were relatively more abundant in the fouling products on SS and Cu, whilst glucose was the most abundant monosaccharide on MS. The monosaccharide and chemical composition data suggest strong temporal changes in the composition of the fouling products.

Bacterial Adhesion↗
PubMed1992

Characterization of the epitope specificity of murine monoclonal antibodies directed against lipid A.

A series of monoclonal antibodies directed against lipid A was characterized by using synthetic lipid A analogs and partial structures. These compounds vary in phosphate substitution, acylation pattern (type, number, and distribution of fatty acids), and, in the case of monosaccharides, in their backbone glycosyl residue. The monoclonal antibodies tested could be subdivided into five groups according to their reactivity patterns. One group reacted exclusively with 1,4'-bisphosphoryl lipid A, and a second also reacted with 4'-monophosphoryl lipid A. Two further groups recognized either 4-phosphoryl or 1-phosphoryl monosaccharide partial structures of lipid A. The fifth group reacted with 4-phosphoryl monosaccharide structures and with phosphate-free compounds. Antibodies reactive with monosaccharide structures also recognized their epitopes in corresponding phosphorylated disaccharide compounds. Both groups of monosaccharide and monophosphoryl lipid A-recognizing antibodies have access to their epitopes in bisphosphoryl compounds as well. Because of this unidirectional reactivity with more complex structures, the various specificities cannot be distinguished by using bisphosphoryl lipid A (e.g., Escherichia coli lipid A) as a test antigen. The epitopes recognized by the various monoclonal antibodies all reside in the hydrophilic backbone of lipid A, and there was no indication that fatty acids were part of the epitopes recognized. Nevertheless, the reactivities of compounds in the different test systems are strongly influenced by their acylation patterns; i.e., acyl groups may modulate the exposure of lipid A epitopes.

Acylation↗
PubMed1990

Analysis of the relationship between bacterial adherence and extracellular production of mannose, galactose, glucose and ribose in Staphylococcus epidermidis and Staphylococcus hominis.

Gas-liquid chromatography-mass spectrometry was used to analyze the extracellular extracts of 108 coagulase-negative staphylococcal strains for the presence of mannose, galactose, glucose and ribose, in order to determine whether production of these four monosaccharides, regarded as potential staphylococcal slime components, was associated with the adherence capacity of the individuals strains. A total of 90 Staphylococcus epidermidis and 18 Staphylococcus hominis strains were studied. Using the quantitative spectrophotometric assay, 21 Staphylococcus epidermidis strains were classified as strongly adherent, 12 as moderately adherent, 11 as weakly adherent, and 46 as nonadherent. All 18 Staphylococcus hominis strains were nonadherent. Mannose, galactose, glucose and ribose were detected as the main monosaccharide components in the extracellular extracts of all strains examined. Moreover, the mean relative concentrations of these monosaccharides were essentially the same for the different adherence phenotypes within the species Staphylococcus epidermidis. These results showed that there was no causal connection between the adherence of coagulase-negative staphylococci and the extracellular production of any of the four monosaccharides analyzed.

Bacterial Adhesion↗
PubMed1992

Role of saccharides in immunoglobulin--Fc receptor interactions.

The rosettes formed by mouse peritoneal macrophages or DCH-5 cells and TNP-erythrocytes coated with anti-TNP antibodies of different isotypes were inhibited to various extent by monosaccharides. The most effective inhibitors were N-acetylglucosamine, glucosamine, mannose and N-acetylneuraminic acid in 1-5 mmol/L concentrations. Even more efficient were glycopeptides isolated from IgG molecules. The Fc receptors (FcRs) released from DCH-5 cells during cultivation and gradually separated by affinity chromatography on immobilized IgG reacted with aggregated IgG and inhibited the rosette formation. The FcRs eluted by monosaccharides influenced mainly the number of rosettes mediated by IgA and IgE while those eluted with a glycine-HCl buffer inhibited preferentially IgG rosettes. As shown by SDS-PAGE the heterogeneity of the fraction eluted with a mixture of monosaccharides revealed one main component with an effective molar mass of 50 kg/mol. The glycine-HCl eluate contained two major components of 55 and 38 kg/mol. The IgG-Sepharose 4B bound all the fractions but only the binding of the 50 kg/mol molecule could be inhibited by monosaccharides.

Animals↗
PubMed1999

Characterisation of cellulose-binding proteins that are involved in the adhesion mechanism of Fibrobacter intestinalis DR7.

Cellulose-binding proteins (CBP) isolated from cell envelopes of the cellulolytic bacterium Fibrobacter intestinalis strain DR7 were studied in order to investigate the adhesion mechanism. The proteins were examined for their reaction with antibodies that specifically block bacterial adhesion, response to glycosylation staining and monosaccharide composition. To this end, the effect of some monosaccharides (CBP components) on blocking of DR7 adhesion to cellulose was determined. Previous study had shown the occurrence of 16 CBP in the outer membrane and periplasm of DR7, of which 6 had endoglucanase activity (Miron and Forsberg 1998). Data from the present study show that most of the 16 CBP of DR7, except for the 38-, 90- and 180-kDa proteins, are glycosylated. Rabbit antibodies that specifically block DR7 adhesion were prepared by affinity preabsorption of antiserum against wild-type DR7 with bacterial cells of its adherence-defective mutant (DR7-M). The preabsorbed antibodies reacted positively in Western blotting with glycosylated CBP of 225, 200, 150, 70, 45 and < 38 kDa from the DR7 outer membrane, and reacted weakly with CBP of DR7-M. Modification of glycosidic residues attached to the CBP of DR7 by periodate oxidation prevented any reaction with the preabsorbed antibodies. Monosaccharide analysis by HPLC of isolated CBP from the outer membrane and periplasm of DR7 cells, showed that galactosamine, glucosamine, galacturonic acid, and glucuronic acid were the predominant monosaccharide components of CBP that can block the adhesion of DR7 cells to cellulose. It is suggested that some glycosylated residues of CBP may have a predominant role in the adhesion of DR7 to cellulose.

Animals↗
PubMed2006

Noncatalytic hydrolysis of guar gum under hydrothermal conditions.

Guar gum, a naturally occurring heteropolysaccharide made of mannose and galactose, was hydrolytically degraded without a catalyst in a batch reactor to produce water-soluble (WS) saccharides including mono- and oligosaccharides. The degradation was carried out under hydrothermal conditions over ranges of temperature from 180 to 240 degrees C and of reaction time from 3 to 60min. Guar gum was readily dissolved and hydrolyzed, and the major products identified in the WS components were oligosaccharides with degrees of polymerization up to about 20, monosaccharides containing mannose and galactose, and 5-hydroxymethyl-2-furaldehyde (5-HMF). At 200 degrees C, the oligosaccharide yield, obtained from the difference between the yields of the total WS saccharides and monosaccharides, showed the highest value of 94.4% at 7min among all conditions studied, on the basis of the saccharide content in the initial sample. The oligosaccharide yield decreased with reaction time, and the yield of monosaccharides correspondingly increased, and reached the highest value of 34.5% (mannose 22.8%, galactose 11.7%) at 60min. The monosaccharides produced were further decomposed to secondary products such as 5-HMF. The maximum yield of 5-HMF obtained was 26.3% at 220 degrees C and 30min. The production and the decomposition of galactose somewhat preceded those of mannose.

Bioreactors↗
PubMed2000

An improved method for quantitative sugar analysis of glycoproteins.

Although there are numerous methods available to hydrolyze glycans utilizing strong acids, it all requires lengthy steps to obtain quantitative yield. We have developed a new simple one-step method for analysis of amino and neutral monosaccharides of glycoproteins quantitatively. Free monosaccharides were found to be stable during hydrolysis of glycans with 6 N HCI at 80 degrees C up to 2 h. Using this condition, analysis of free monosaccharides hydrolyzed from the bovine fetuin showed sugar composition of Gal: Man: GlcN: GaIN = 13.2: 11.0: 15.5: 2.6, which is closely matched with the reported value of 12.4: 9.6: 17.2: 2.7 (Townsend et al., ABRF News 8: 14, 1997). This method was shown to be applicable to varieties of well-characterized glycoproteins, erythropoietin, fibrinogen and soybean agglutinin. The amounts of sugars released under the condition were very close to the experimental values by other procedures or to the theoretical ones. This condition was found to be suitable for direct sugar analysis of fetuin, which have been immobilized onto polyvinylidene difluoride membrane. Based on these results, it support that the 6 N HCl/80 degrees C/2 h is the simplest method for quantitative analysis of monosaccharide composition of glycoproteins.

Amino Sugars↗
PubMed1998

Quantitative analysis of sugar constituents of glycoproteins by capillary electrophoresis.

A method for quantitative analysis of monosaccharides including N-acetylneuraminic acid derived from sialic acid-containing oligosaccharides and glycoproteins is presented. The analysis is based on the combination of chemical and enzymatic methods coupled with capillary electrophoretic (CE) separation and laser-induced fluorescence (LIF) detection. The present method utilizes a simplified acid hydrolysis procedure consisting of mild hydrolysis (0.1 M TFA) to release sialic acid and strong acid hydrolysis (2.0 N TFA) to produce amino and neutral sugars. Amino sugars released from strong acid hydrolysis of oligosaccharides and glycoproteins were reacetylated and derivatized with 8-aminopyrene-1,3,6-trisulfonate (APTS) along with neutral sugars in the presence of sodium cyanoborohydride to yield quantitatively the highly stable fluorescent APTS adducts. N-acetylneuraminic acid (Neu5Ac), a major component of most mammalian glycoproteins, was converted in a fast specific reaction by the action of neuraminic acid aldolase (N-acylneuraminate pyruvate-lyase EC 4.1.3.3) to N-acetylmannosamine (ManNAc) and pyruvate. ManNAc was then derivatized with APTS in the same manner as the other monosaccharides. This method was demonstrated for the quantitation of pure Neu5Ac and the species derived from mild acid hydrolysis of 6'-sialyl-N-acetyllactosamine and bovine fetuin glycan. Quantitative recovery of the N-acetylmannosamine was obtained from a known amount of Neu5Ac in a mixture of seven other monosaccharides or from the sialylated oligosaccharides occurring in glycoproteins. The sequence of procedures consists of acid hydrolysis, enzymatic conversion and APTS derivatization which produced quantitative recovery of APTS-monosaccharide adducts. The detection limits for sugars derivatized with APTS and detected by CE-LIF are 100 pmol for Neu5Ac and 50 pmol for the other sugars.

Amino Sugars↗
PubMed1999

Sequential deglycosylation and utilization of the N-linked, complex-type glycans of human alpha1-acid glycoprotein mediates growth of Streptococcus oralis.

Streptococcus oralis is the agent of a large number of infections in immunocompromised patients, but little is known regarding the mechanisms by which this fermentative organism proliferates in vivo. Glycoproteins are widespread within the circulation and host tissues, and could provide a source of fermentable carbohydrate for the growth of those pathogenic organisms with the capacity to release monosaccharides from glycans via the production of specific glycosidases. The ability of acute phase serum alpha1-acid glycoprotein to support growth of S.oralis in vitro has been examined as a model for growth of this organism on N-linked glycoproteins. Growth was accompanied by the production of a range of glycosidases (sialidase, N-acetyl-beta-D-glucosaminidase, and beta-D-galactosidase) as measured using the 4-methylumbelliferone-linked substrates. The residual glycoprotein glycans remaining during growth of this organism were released by treatment with hydrazine and their analysis by HPAEC-PAD and MALDI demonstrated extensive degradation of all glycan chains with only terminal N-acetylglucosamine residues attached to asparagines of the protein backbone remaining when growth was complete. Monosaccharides were released sequentially from the glycans by S.oralis glycosidases in the order sialic acid, galactose, fucose, nonterminal N-acetylglucosamine, and mannose due to the actions of exo-glycosidic activities, including mannosidases which have not previously been reported for S.oralis. All released monosaccharides were metabolized during growth with the exception of fucose which remained free in culture supernatants. Direct release of oligosaccharides was not observed, indicating the absence of endo-glycosidases in S.oralis. We propose that this mechanism of deglycosylation of host glycoproteins and the subsequent utilization of released monosaccharides is important in the survival and persistence of this and other pathogenic bacteria in vivo.

Carbohydrate Sequence↗
PubMed1985

Activation and inhibition of Limulus amebocyte lysate coagulation by chemically defined substructures of lipid A.

Recent work with lipid mutants of Escherichia coli and Salmonella typhimurium has helped to elucidate the correct structure of lipid A and has suggested a biosynthetic pathway. Precursor molecules include diacylglucosamine 1-phosphates and tetraacyl disaccharide bis-phosphates. The activities of several of these compounds and of their derivatives were measured by Limulus amebocyte lysate (LAL) assay. We report that (i) both mono- and disaccharide precursors of lipid A activate LAL, (ii) two acyl chains on the monosaccharide subunit of lipid A are necessary for activation of LAL, and (iii) the monosaccharide, 2-monoacylglucosamine 1-phosphate can competitively inhibit LAL activation by diacyl monosaccharide lipid A precursors. However, 2-monoacylglucosamine 1-phosphate did not inhibit endotoxin activation of LAL. One unanticipated finding was that the activities of the monosaccharides were reduced upon storage even though their covalent structures were unchanged. Perhaps this is due to alterations in physical state. Thus, these lipid A precursors and derivatives offer some insight into the structural features required for activation of the LAL assay and may in the future provide derivatives which are competitive inhibitors of endotoxin.

Drug Stability↗
PubMed2003

[Saccharide analysis of si-wu-tang by automated multiple development and off-line coupling thin layer chromatography electrospray ionization mass spectrometry techniques].

OBJECTIVE: To make qualitative analysis on saccharide spots in thin layer chromatography (TLC) chromatogram of SI-WU-TANG extract C, which possesses blood-enrichment activity. METHOD: TLC chromatogram of SI-WU-TANG extract C was obtained by using Automated Multiple Development (AMD) method. 4 major spots in the chromatogram were analyzed by off-line coupling TLC electrospray ionization mass spectrometry (ESI-MS) technique. Moreover, composition of monosaccharides in the fraction was analyzed by AMD technique. RESULT: Main constituents of substances from the 4 spots were monosaccharide, disaccharide, trisaccharide and tetrasaccharide respectively. Monosaccharide was mainly composed of fructose and glucose. CONCLUSION: Off-line coupling TLC ESI-MS can simply and rapidly provide qualitative examination of saccharide spots in TLC chromatogram of Traditional Chinese Medicine. AMD method can make good separation of 8 frequently-observed monosaccharides in a regular 10 cm silica gel plate, the process of which was automated, AMD and off-line coupling TLC ESI-MS techniques show good value in saccharides analysis.

Angelica sinensis↗
PubMed1979

Effect of growth conditions on the content of the major groups of carbohydrates in chick embryo fibroblasts.

The levels of glycogen, hyaluronic acid, chondroitin sulfates, N-acetylneuraminic acid, all of the monosaccharide components of the glycoprotein and glycolipid fractions, and the monosaccharide pools were measured in cultured chick embryo fibroblasts. Under all growth conditions, the glycogen plus the glucose phosphate pool contained approximately 50% of total monosaccharide content of the cells. However, marked qualitative and quantitative alterations were found in the glycoprotein, glycolipid, and mucopolysaccharide fractions when growing cells reached confluence, when the growth temperature was shifted from 36 to 41 degrees, or when the cells were transformed with Rous sarcoma virus. From 65 to 95% of the total monosaccharide residues in these complex carbohydrates were found in the glycoprotein fraction, while the glycolipids contained only 5 to 10% of the residues, and the mucopolysaccharides contained 5 to 25%. Changes in the complex carbohydrates in normal cells following changes in cell density or growth temperature were so great that they obscured any transformation-dependent changes that might have occurred consistently in the virus-infected cells under different growth conditions.

Animals↗
PubMed1999

BOLD--a biological O-linked glycan database.

Glycans can be O-linked to proteins via the hydroxyl group of serine, threonine, tyrosine, hydroxylysine or hydroxyproline. Sometimes the glycan is O-linked to the hydroxyl group via a phosphodiester bond. The core monosaccharide residue may be N-acetylgalactosamine, N-acetylglucosamine, galactose, glucose, fucose, mannose, xylose or arabinose. These O-linked glycans can remain as a monosaccharide, but often a complex structure is built up by stepwise addition of monosaccharides. Monosaccharides known to be added include galactose, N-acetylglucosamine, fucose, N-acetylneuraminic acid, N-glycolylneuraminic acid and 2-keto-3-deoxynonulosonic acid. O-linked glycans can also contain sulfate and phosphate residues. This leads to the possibility of the existence of numerous O-glycan structures. The biological O-linked database (BOLD) is a relational database that contains information on O-linked glycan structures, their biological sources (with a link to the SWISS-PROT protein database), the references in which the glycan was described (with a link to MEDLINE), and the methods used to determine the glycan structure. The database provides a valuable resource for glycobiology researchers interested in O-linked oligosaccharide structures that have been previously described on proteins from different species and tissues.

Carbohydrate Conformation↗
PubMed2001

Quantitative analysis of the regulation scheme of invertase expression in Saccharomyces cerevisiae.

In Saccharomyces cerevisiae, the expression of invertase, which is the hydrolyzing enzyme of sucrose, is controlled by the presence of monosaccharides, such as glucose and fructose, and referred to as carbon catabolite repression. To date, efforts have been made to identify the mechanism by which cells sense extracellular monosaccharide concentrations and trigger the genes involved in the repression pathway. The aim of the present work was to quantitatively investigate the cellular regulation of invertase expression in the wild-type strain S. cerevisiae CEN.PK113-7D during batch growth containing mixed sugar substrates under different initial conditions. Because of the high frequency and accurate online analysis of multiple components, a tight control of invertase expression could be observed, and threshold concentrations of the monosaccharides for derepression could be determined to 0.5 gl(-1) for glucose and 2 gl(-1) for fructose. Also, the existence of a hitherto undescribed regulatory state, in which cells regulate invertase expression very precisely and operate over long periods at monosaccharide concentrations lower than the above thresholds, could be demonstrated. All experimental observations could be summarized in a formulation of the cellular regulation scheme of invertase expression. A simple kinetic model could show that the regulation scheme explains the observed behavior very well. Additionally, the model was able to explain consequences of the regulation on the global metabolism.

Bioreactors↗
PubMed1994

Influence of polysaccharides on neutrophil function: specific antagonists suggest a model for cooperative saccharide-associated inhibition of immune complex-triggered superoxide production.

We have previously shown that certain monosaccharides (N-acetyl-D-glucosamine and mannose) could cooperatively inhibit the ability of neutrophils to release superoxide anions in response to immune complexes. To test the possible origins of the cooperative inhibition of superoxide release, we have examined the effect of a panel of polysaccharides on superoxide release in the presence or absence of immune complexes. Although exposure to particulate beta-glucan and hyaluronan triggered superoxide release from neutrophils, other polysaccharides including chitin and mannan were without effect. Both chitin and mannan, but not other polysaccharides, inhibited the immune complex-mediated stimulation of superoxide release in a dose-dependent fashion. In sharp contrast to the cooperative inhibition mediated by monosaccharides, chitin and mannan exhibited Hill coefficients of 1. This inhibition of superoxide production was not due to simple blockage of Fc receptors since fluorescent immune complexes bound equally well to neutrophils in the presence or absence of mannan or chitin as shown by epifluorescence microscopy and quantitative fluorometry. Furthermore, this inhibition of superoxide release was not observed when neutrophils were stimulated with phorbol myristate acetate and ionophore A23187 or hyaluronan. Therefore, the specific inhibition of superoxide production by mannan and chitin could not be explained by either receptor blockage or by some nonspecific effect on cells. We suggest that these molecules interfere with a step in transmembrane signaling, presumably involving the integrin CR3. The observed Hill coefficients suggest the possibility that one polysaccharide may simultaneously bind to two monosaccharide binding sites yielding a Hill coefficient of 1, whereas individual monosaccharides separately bind yielding a Hill coefficient of 2.

Adult↗
PubMedDate not supplied

Determination of aldoses and ketoses by GC-MS using differential derivatisation.

A method has been established by which to determine aldoses and ketoses in plant material simultaneously. Monosaccharides were extracted by sonication with 80% ethanol and sugar oximes formed by treatment of the resultant extract with hydroxylamine and pyridine at 90 degrees C. After reaction, one aliquot of the product was derivatised with acetic anhydride at 90 degrees C, whilst a second aliquot was silylated with HMDS and TMCS at 80 degrees C. Both reaction mixtures were analysed by GC-MS in the SIM mode. Quantivation was linear within the range 1-4 microg/mL and the detection limit for monosaccharides was 5-25 ng/mL. The absolute recoveries were between 73.0 and 90.2% and the RSDs were 3.1-10.0%. This method was applied to analyse the free monosaccharides in Lyceum barbarum L.; eight monosaccharides were present in amounts between 0.26 and 368.65 microg/mg.

Carbohydrates↗
PubMed1998

A gas chromatographic method for the sugar analysis of 3,6-anhydrogalactose-containing algal galactans.

This paper describes a new gas chromatographic method for the compositional analysis of algal galactans containing 3,6-anhydrogalactose, which is readily destroyed in usual acid hydrolysis and methanolysis. Mercaptolysis of galactans was carried out under an anhydrous condition using the newly developed solvent system, an ethanethiolic HCl solution which had been prepared by blowing dry HCl gas into ethanethiol. By heating galactans in 0.5 N HCl/ethanethiol at 60 degrees C for 12 h, component sugars including 3,6-anhydrogalactose were released quantitatively as their diethyl mercaptals. The monosaccharide diethyl mercaptals were trimethylsilylated and analyzed by gas-liquid chromatography. Each component monosaccharide was detected as a single peak since neither anomeric nor structural isomers can be produced by mercaptolysis. Furthermore, the solvent system was improved by the addition of methanol in a ratio (2/1, v/v) of ethanethiol to methanol. Heating of galactans at 60 degrees C in 0.5 N HCl/[ethanethiol:methanol (2/1, v/v)] released more rapidly and quantitatively monosaccharide diethyl mercaptals without any formation of monosaccharide methyl glycosides. The present method was applicable to not only algal galactans but also algal powders.

Carbohydrate Sequence↗
PubMed1998

Volatile components formed from reaction of sugar and beta-alanine as a model system of cookie processing.

Volatile components formed from the reaction of monosaccharides or disaccharides with beta-alanine were investigated in a dry condition as a model system of cookie processing. Maltol is a common compound formed in the Maillard reaction, but it was very difficult to detect it in previous experiments using actual cookie materials. In this work, we investigated the principal compounds and maltol formation from the reaction of monosaccharides or disaccharides with beta-alanine at 150 degrees C for 10 min. Neither the reaction of monosaccharides nor the disaccharides with beta-alanine resulted in the formation of maltol. 2,3-Dihydro-3,5-dihydroxy-6-methyl-4(H)-pyran-4-one (DDMP) was detected as a principal product from the reaction of monosaccharides with beta-alanine. 5-Hydroxymethyl-2-furfural was also confirmed as being a major product in both reactions.

Acetylation↗