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PubMed1975

Agglutinin from Limulus polyphemus. Purification with formalinized horse erythrocytes as the affinity adsorbent.

We have purified an agglutinin from the hemolymph of Limulus polyphemus about 1500-3000-fold by adsorption to formalinized horse erythrocytes, elution with N-acetylneuraminic acid and subsequent fractionation on Sephadex G-200. Recovery was in the range of 50 percent. On ultracentrifugation the agglutinin behaves as an homogenous protein with a molecular weight of about 460 000. On polyacrylamide gel electrophoresis of the dissociated protein in sodium dodecylsulfate we found a single prominent diffuse band with an apparent molecular weight of 22 000 plus or minus 2000. This band contained carbohydrate as determined by periodic acid-Schiff staining. The intensity of staining compared with standards suggested a carbohydrate content of less than 4 percent. The protein contains a preponderance of acidic amino acids and has an isoelectric point of 4.83.5 residues per 1000 of glucosamine were detected on amino acid analysis. Agglutination of formalinized horse erythrocytes by the purified protein is inhibited not only by N-acetylneuraminic acid but also by D-glucuronic acid; but not by a number of other monosaccharides. D-Glucuronic acid may be used in place of N-acetylneuraminic acid as the eluting sugar in the purification procedure.

Agglutinins↗
PubMed1990

[Glyyunnanprosapogenin and glyyunnansapogenin from the roots of Glycyrrhiza yunnanensis].

Two new triterpenoidal sapogenins of oleanane type, namely glyyunnanprosapogenin D (V) and glyyunnansapogenin F (IX) were isolated from the roots of Glycyrrhiza yunnanensis Cheng f. et L. K. Tai, family Leguminosae, collected from Yunnan Province, China. V was obtained as hexaacetate and dimethyl ester form (Vc), mp 168-170 degrees C, C56H78O22, which gave an aglycone macedonic acid (V') and two molecules of glucuronic acid after hydrolysis with hydrochloric acid. The spectral analysis of 13CNMR and 1HNMR showed that Vc had two glycoside residues attached to the aglycone, and therefore the structure of V was established as oleana-11, 13(18)-dien-29-oic acid, 3 beta, 21 alpha-di-(O-beta-D-glucuronic acid) pyranoside. IX was obtained as its diacetate and monomethyl ester form (IXc), mp 188-190 degrees C, C35H50O7. The IR, 1HNMR and UV spectra showed that the IXc had a skeleton of oleanane type triterpenoid with heteroannular diene. IXb, diacetate of IX, unpurified, was converted to IXf with chromium trioxide in glacial acetic acid. IXf, mp 160-164 degrees C, C30H46O8, was proved to be olean-12-en-11-oxo-3 beta,24-diacetoxy-18 beta-hydroxy-30-oic acid, 30 in equilibrium 18 beta lactone with another carbonyl group at C-15,16,21 or 22 by the analysis of 13CNMR, 1HNMR and MS spectra.(ABSTRACT TRUNCATED AT 250 WORDS)

Drugs, Chinese Herbal↗
PubMed1996

Enzymological characterization of the Pasteurella multocida hyaluronic acid synthase.

Hyaluronic acid (HA), a linear polysaccharide composed of alternating glucuronic acid and N-acetylglucosamine residues, is an essential molecule of higher vertebrates. The fowl cholera pathogen Pasteurella multocida Carter Type A also produces HA in the form of an extracellular capsule in order to evade host defenses. HA synthase activity could be obtained from cell-free membrane preparations of P. multocida. The enzyme utilized UDP-sugar precursors of HA in the presence of Mg2+ or Mn2+ at neutral pH. Mn2+ at 1 mM stimulated approximately 2-fold more incorporation than Mg2+ at 10 mM. On the other hand, the analogous enzyme from group A Streptococcus, HasA, is stimulated more by Mg2+ than Mn2+. The apparent Michaelis constants, K(M), of the P. multocida HA synthase for UDP-N-acetylglucosamine and UDP-glucuronic acid were estimated to be approximately 75 and approximately 20 microM, respectively, in the presence of Mg2+, which suggests that the substrates are bound with 2-3-fold higher affinity than by the HasA enzyme. The rate enhancement observed with Mn2+ is apparently not due to better binding of the sugar nucleotide precursors complexed to Mn ion because the K(M) value, a measure of substrate affinity, increases by 25-50% in comparison to Mg2+. In summary, the HA synthase from P. multocida, a Gram-negative bacterium, has kinetic optima distinct from those of HasA, the analog from the Gram-positive group A Streptococcus.

Cell Membrane↗
PubMed1981

Effect of long generation times on growth of Bacteroides thetaiotaomicron in carbohydrate-induced continuous culture.

We investigated the ability of Bacteroides thetaiotaomicron, an obligate anaerobe from human colonic microflora, to grow in a carbohydrate-limited continuous culture at generation times ranging from 3.5 to 28 h per division. Four carbohydrates were tested: glucose, N-acetylglucosamine, glucuronic acid, and glucosamine. At a generation time of 3.5 h per division, the growth yields for bacteria growing on glucose, N-acetylglucosamine, and glucuronic acid were 76, 68, and 50 g of cells (dry weight) per mol of substrate, respectively. Growth yields at 28 h per division were 61, 52, and 37 g/mol of substrate, respectively. When glucosamine was the carbohydrate source, a stable population of bacteria was attainable only at generation times longer than 12 h per division. Growth yields at 15 and 32 h per division were 11 and 33 g/mol of substrate, respectively. There was no significant variation with increasing generation times in the specific activities of selected glycolytic enzymes, of disaccharidases such as alpha- and beta-glucosidases and alpha- and beta-galactosidases, or of the polysaccharidase chondroitin sulfate lyase. By contrast, the pattern of fermentation products varied with both the generation time and the carbon source. At a generation time of 3.5 h per division, the main products from the fermentation of glucose were acetate and succinate, with a trace of propionate. At 28 h per division, propionate concentrations were higher and succinate concentrations were lower than at 3.5 h per division. The products from the fermentation of glucosamine were the same as those from glucose fermentation. However, when N-acetylglucosamine was fermented, the concentration of acetate was much higher at all generation times than when glucose was the carbon source. When glucuronic acid was the carbon source, acetate was the main fermentation product, and only traces of propionate and succinate were detected. Another characteristic that varied with the growth rate was the ability of B. thetaiotaomicron to produce the inducible enzyme alpha-glucosidase when exposed to maltose. The ability of the organism to produce this enzyme declined with increasing generation times.

Acetylglucosamine↗
PubMed1983

A glucuronyltransferase involved in glucuronoxylan synthesis in pea (Pisum sativum) epicotyls.

A particulate enzyme preparation made from epicotyls of 1-week-old etiolated pea (Pisum sativum) seedlings was shown to incorporate glucuronic acid from UDP-D-[U-14C]glucuronic acid into a hemicellulosic polysaccharide. Optimum conditions for the incorporation include the presence of Mn2+ ions at between 4 and 10 mmol/litre and a pH between 5 and 6. UDP-D-xylose at 1 mmol/litre allows incorporation to continue for at least 8 h. In its absence, the reaction stops within 30 min. Analysis of the product by partial and total acid hydrolysis, followed by paper chromatography or electrophoresis, indicates that the polysaccharide produced is a glucuronoxylan.

Cations, Divalent↗
PubMed2005

Increase in hyaluronic acid production by Streptococcus equi subsp. zooepidemicus strain deficient in beta-glucuronidase in laboratory conditions.

Streptococcus equi subsp. zooepidemicus is known to produce a hyaluronic acid capsule to resist the host immune defense. As the structure of the polysaccharide is identical to the one produced by humans, the bacteria S. equi subsp. zooepidemicus is used in biotechnological production of hyaluronic acid. In our laboratory we prepared mutated strains that are beta-glucuronidase deficient. Comparing the wild-type strain, which is positive in beta-glucuronidase activity, with the mutated strains named clone1 and clone2 in laboratory conditions, we observed that beta-glucuronidase influences the production of hyaluronic acid considerably and the molecular weight of hyaluronan slightly. The production of hyaluronic acid by the mutated strains is higher by approximately 20% and the molecular weight is larger by about 2%. The significant increase in the production of hyaluronic acid and the slight increase in the molecular weight are probably caused by an absence of free beta-glucuronic acid, due to its removal from the non-reducing termini of the polysaccharide by beta-glucuronidase. The presence of free beta-glucuronic acid would likely induce the expression of the beta-glucuronic-acid-utilizing operon, which in turn would reflect into a misuse of energy in the glucose-rich media.

Chromatography, Gel↗
PubMed1987

Separation by ion-pair high-performance liquid chromatography of the glucuronide, sulfate and glutathione conjugates formed from benzo[a]pyrene in cell cultures from rodents, fish and humans.

A large proportion of the metabolites formed from benzo[a]pyrene (BP) in cell cultures from rodents, fish and humans result from conjugation of an oxidized metabolite of BP with sulfate, glucuronic acid or glutathione (GSH). To improve the analysis of these metabolites, a reversed-phase ion-pair h.p.l.c. system using a step gradient of methanol:tetrabutyl-ammonium bromide in ammonium formate buffer has been developed for the separation of these three classes of conjugates. This system separated 3-hydroxy-BP glucuronide and sulfate conjugates and resolved them from GSH conjugates of BP 4,5-oxide, 7,8-oxide and 7,8-diol-9,10-epoxide. Cultures of early passage Syrian hamster, Wistar rat and Sencar mouse embryo cells, a bluegill fry (BF-2) cell line and a human hepatoma cell line (HepG2) were exposed to [3H]BP for 24 h. Medium samples from each were extracted with chloroform: methanol:water, and the water-soluble metabolites were analyzed by ion-pair h.p.l.c. The largest peak of metabolites in the media from cell cultures from rodents and the bluegill fry cell line co-eluted with the glucuronic acid conjugate of 3-hydroxy-BP. These phenol-glucuronides represented 48-62% of the total water-soluble metabolites in the fish and rodent cell cultures. Treatment of this material with beta-glucuronidase released 3-hydroxy-BP and 9-hydroxy-BP in ratios from 3:4 to 13.3:1 in various cultures. Media from the bluegill fry cell line and the mouse embryo cell cultures also contained a peak of BP-diol glucuronides; treatment of these peaks with beta-glucuronidase released mainly BP-7,8-diol. In HepG2 cells, 40% of the water-soluble metabolites were identified as sulfate conjugates of 3-hydroxy-BP and 9-hydroxy-BP. No glucuronic acid conjugates of BP metabolites were detected in HepG2 cells. Only small amounts of the water-soluble metabolites from these cell cultures eluted in the same volumes as the synthetic GSH conjugate of BP-4,5-oxide, BP-7,8-oxide and BP-7,8-diol-9,10-oxide. These studies indicate that conjugation with glucuronic acid represents a major pathway of formation of water-soluble metabolites from BP in cells derived from a number of species and demonstrate the value of this ion-pair h.p.l.c. system for the analysis of conjugates formed from BP.

Animals↗
PubMed1982

Major sites of metal binding in Bacillus licheniformis walls.

Isolated and purified walls of Bacillus licheniformis NCTC 6346 his contained peptidoglycan, teichoic acid, and teichuronic acid (0.36 mumol of diaminopimelic acid, 0.85 mumol of organic phosphorus, and 0.43 mumol of glucuronic acid per mg [dry weight] of walls, respectively). The walls also contained a total of 0.208 mumol of metal per mg. When these walls were subjected to metal-binding conditions (T. J. Beveridge and R. G. E. Murray, J. Bacteriol. 127:1502-1518, 1976) for nine metals, the amount of bound metal above background ranged from 0.910 mumol of Na to 0.031 mumol of Au per mg of walls. Most were in the 0.500-mumol mg-1 range. Electron-scattering profiles from unstained thin sections indicated that the metal was dispersed throughout the wall fabric. Mild alkali treatment extracted teichoic acid from the walls (97% based on phosphorus) but left the peptidoglycan and teichuronic acid intact. This treatment reduced their capacity for all metals but Au. Thin sections revealed that the wall thickness had been reduced by one-third, but metal was still dispersed throughout the wall fabric. Trichloroacetic acid treatment of the teichoic acid-less walls removed 95% of the teichuronic acid (based on glucuronic acid) but left the peptidoglycan intact (based on sedimentable diaminopimelic acid). The thickness of these walls was not further reduced, but little binding capacity remained (usually less than 10% of the original binding). The staining of these walls with Au produced a 14.4-nm repeat frequency within the peptidoglycan fabric. Sedimentation velocity experiments with the extracted teichuronic acid in the presence of metal confirmed it to be a potent metal-complexing polymer. These results indicated that teichoic and teichuronic acids are the prime sites of metal binding in B. licheniformis walls.

Bacillus↗
PubMed1992

Insect glial cells show differential expression of a glycolipid-derived, glucuronic acid-containing epitope throughout neurogenesis: detection during postembryogenesis and regeneration in the central nervous system of Tenebrio molitor L.

The monoclonal antibody CAF-1 recognises a glucuronic acid-containing epitope present on insect acidic glycolipids. Immunohistochemical analysis of the CAF-1 epitope has revealed its differential, temporal and spatial expression during postembryogenesis of the midbrain of Tenebrio molitor. Electron microscopic resolution demonstrated, that the CAF-1 epitope is expressed on glial cells that ensheath the glomeruli of the central body. Concomitantly, a differential pattern of expression was observed in the ventral nerve cord, exhibiting a serially homologous display on glial cells that ensheath neuronal somata in the cell body layer of the thoracic ganglia and ventral associative neuropil. Prominent, topologically restricted CAF-1 immunoreactivity was monitored in termination areas of sensory neurons in the ventral associative neuropil and corresponding nerves 6-48 h after extirpation of the respective sensory neuron somata. CAF-1 expression is correlated with structural reorganisation in postembryonic nervous tissue of T. molitor.

Animals↗
PubMed2004

UDP-glucose dehydrogenase plays multiple roles in the biology of the pathogenic fungus Cryptococcus neoformans.

Cryptococcus neoformans is a pathogenic fungus surrounded by an elaborate polysaccharide capsule that is strictly required for its virulence in humans and other mammals. Nearly half of the sugar residues in the capsule are derived from UDP-glucuronic acid or its metabolites. To examine the role of these nucleotide sugars in C. neoformans, the gene encoding UDP-glucose dehydrogenase was disrupted. Mass spectrometry analysis of nucleotide sugar pools showed that the resulting mutant lacked both UDP-glucuronic acid and its downstream product, UDP-xylose, thus confirming the effect of the knockout and indicating that an alternate pathway for UDP-glucuronic acid production was not used. The mutant was dramatically affected by the lack of specific sugar donors, demonstrating altered cell integrity, temperature sensitivity, lack of growth in an animal model of cryptococcosis, and morphological defects. Additionally, the polysaccharide capsule could not be detected on the mutant cells, although the possibility remains that abbreviated forms of capsule components are made, possibly without proper surface display. The capsule defect is largely independent of the other observed changes, as cells that are acapsular because of mutations in other genes show lack of virulence but do not exhibit alterations in cell integrity, temperature sensitivity, or cellular morphology. All of the observed alterations were reversed by correction of the gene disruption.

Antibodies, Monoclonal↗
PubMed1995

Food restriction stimulates conjugation of p-nitrophenol in perfused rat liver.

Rates of conjugation of p-nitrophenol were studied in livers from normal and food-restricted rats perfused with either p-nitroanisole or p-nitrophenol. Female Sprague-Dawley rats had ad libitum access to a Purina 5001 nonpurified diet (control) or were given 65% of the intake of controls for 3 weeks. Livers were perfused with oxygenated Krebs-Henseleit buffer using a nonrecirculating system. Maximal rates of conjugation of p-nitrophenol, generated either from the O-demethylation of p-nitroanisole (200 microM) or from the infusion of p-nitrophenol (70 microM), were elevated significantly nearly twofold by food restriction. Thus, food restriction stimulates conjugation in the intact liver cell. Specifically, rates of conjugation were increased from 2.1 +/- 0.2 to 3.7 +/- 0.4 and from 3.3 +/- 0.6 to 5.8 +/- 0.5 mumol/g/h when 200 microM p-nitroanisole or 70 microM p-nitrophenol were infused, respectively. On the other hand, rates of conjugation were not affected by food restriction when low concentrations of p-nitroanisole (50 microM) or p-nitrophenol (20 microM) were infused. Further, food restriction did not alter rates of conjugation in isolated microsomes supplemented with excess UDPGA. Interestingly, both UDP-glucose and UDP-glucuronic acid were increased significantly in liver extracts from food-restricted rats when livers were perfused with high but not low concentrations of p-nitrophenol. Under these conditions, the increase in UDP-glucuronic acid was threefold. Moreover, food restriction increased carbohydrate release from the liver about twofold. Glycogen content was also increased significantly in liver extracts from 8.4 +/- 1.9 to 60.4 +/- 13.8 mmol/kg wet weight by food restriction. Taken together, these data support the hypothesis that food restriction stimulates conjugation of p-nitrophenol concentrations by increasing the supply of the pivotal cofactor UDP-glucuronic acid from carbohydrate reserves (e.g., glycogen).

Animals↗
PubMed1996

Direct detection and identification of radicals generated during the hydroxyl radical-induced degradation of hyaluronic acid and related materials.

HO. attack on hyaluronic acid, related polymers and monomers has been studied by both direct, rapid-flow, EPR (ESR) and EPR spin trapping using a variety of traps. Evidence has been obtained, with the monomers, for essentially random hydrogen-atom abstraction at all the ring C -- H bonds with glucuronic acid, and at all sites except the N-acetyl side chain and C(2) with N-acetylglucosamine. The initial radicals do not undergo rapid rearrangement reactions at pH 4; however at both lower and higher pH values, acid- and base-catalysed rearrangement process, respectively, result in the loss of these species. The rate of loss of these species is dependent on the substrate, with those derived from N-acetylglucosamine undergoing slowed acid-catalysed rearrangement than the glucuronic acid-derived species. This is rationalised in terms of a rearrangement reaction of 1.2-dihydroxyalkyl(1.2-dio) radicals involving an electron-deficient radical-cation intermediate; the formation of this species would be disfavoured by the electron-withdrawing N-acetyl substituent. The base-catalysed process, which is believed to involve a radical-anion intermediate, occurs rapidly at pH 7.4, and appears to be less substrate dependent. In the case of glucuronic acid- (but not N-acetylglucosamine-) derived species this latter process results in the detection of ring-opened semidione species. With equimolar mixtures of the two monomers essentially random attack occurs on the two rings. However with chondroitin sulphate A, attack appears to be much more selective, with a radical generated at C(5) on the glucuronic acid ring present at highest concentration. The initial radicals obtained with this polysaccharide also undergo base- and acid-catalysed rearrangements; this leads to strand-breakage and the formation of low-molecular-weight material. Spin-trapping experiments carried out with hyaluronic acid, and a number of other polysaccharides, resulted in the detection of a number of novel spin adducts, the formation of which are consistent with attack on both the sugar rings in the polymer. The pH dependence of the observed spectra, and the detection of additional species at some pH values, suggest that at least some of the initial radicals undergo base-catalysed rearrangement reactions which result in strand-breakage and the formation of low-molecular-weight fragments. The extent of fragmentation at a particular pH, is also affected by the radical flux, with high radical yields giving more low-molecular-weight material. These observations suggest that pH-independent processes also contribute to strand-cleavage; this may be due to beta-cleavage of the radicals formed at C(1) on either ring, C(3) on N-acetylglucosamine or C(4) on the glucuronic acid ring.

Acetylglucosamine↗
PubMed2003

Glucuronuria in the koala.

Glucuronuria is normal in marsupial folivores such as the koala (Phascolarrctos cinereus), which excretes 2-3 g glucuronic acid daily. Although this has long been attributed to the metabolites of Eucalyptus terpenes, we have found that these are mostly excreted in the unconjugated form. We now report on the aglycones that account for most of the glucuronic acid in koala urine. Urine (24 hr) was collected from six male koalas (8.8 +/- 0.4 kg, mean +/- SE) that were maintained on E. cephalocarpa foliage. Urine samples were analyzed by liquid and gas chromatography (LC and GC) coupled with mass spectrometry (MS). Glucuronides were readily identified by LC-MS/MS, which generated characteristic product ions at m/z 113 and 175. From the corresponding parent glucuronide ions, the masses of the aglycones were calculated. Confirmation of identity was by GC-MS after hydrolysis with beta-glucuronidase and comparison with standard compounds. Quantitation was by GC. The major non-terpene aglycones were 4-methylcatechol, resorcinol, salicyl alcohol, and two unidentified C7H8O2 phenols. Smaller amounts of benzoic acid, benzyl alcohol, orcinol, p-cresol, phenol, and phloroglucinol were detected. We have previously reported that terpene metabolites account for about 10% urinary glucuronides in the same koalas fed E. cephalocarpa. The present study found that an additional 60% urinary glucuronic acid is conjugated with non-terpene, mainly phenolic, aglycones. It seems likely that these phenolic compounds are present in leaves as glycosides and are chiefly responsible for the glucuronuria in koalas.

Animals↗
PubMed1982

Structural differences between beef-lung heparan sulphates with specific self-associations.

Three, specifically self-associating variants of heparan sulphate (HS2-A, HS3-A, and HS4-A) from beef lung were subjected to (a) deaminative cleavage of bonds between 2-deoxy-2-sulphoaminoglucose and uronic acid and (b) periodate oxidation of glucuronic acid residues in fully N-acetylated block-regions. In addition, the periodate-oxidised and alkali-cleaved chains were re-oxidised with periodate to identify the glucuronic acid residues in the N-sulphate-containing regions. The results showed that HS2-A was distinguished by much longer (GlcA-GlcNAc)n-segments than HS3-A and HS4-A. The latter two species were characterised by the structure of the variously N-acetyl- and N-sulphate-containing regions. In HS3-A, there was a significant contribution from segments composed of both N-acetylated and N-sulphated 2-amino-2-deoxyglucose residues. The N-sulphate-rich regions contained chiefly iduronic acid. In contrast, HS4-A had mixed or alternating arrangements of the two epimeric uronic acids in the N-sulphate-rich regions. These differences may be the basis for specific self-associations between heparan sulphate chains.

Animals↗
PubMed1997

Immortalized, cloned mouse chondrocytic cells (MC615) produce three different matrix proteoglycans with core-protein-specific chondroitin/dermatan sulphate structures.

Cloned immortalized MC615 mouse chondrocytic cells were used to examine their capability to produce multiple types of matrix proteoglycans. Immunofluorescence staining indicated a uniform expression of aggrecan, biglycan and decorin by all cells. After culture with [35S]sulphate, proteo[35S]glycans secreted by the cells were found to elute in two peaks from a Sepharose CL-4B column. The first peak, at the void volume of the column, contained a large proteoglycan with an estimated average hydrodynamic mass of 10(3) kDa. The glycosaminoglycan chains of this proteoglycan had an average hydrodynamic size of 17 kDa, estimated by Sepharose CL-6B chromatography, indicating the presence of 30-70 glycosaminoglycan chains per core protein, which was consistent with the characteristics of aggrecan. Biglycan and decorin were immunoisolated from the second Sepharose CL-4B peak, and had average glycosaminoglycan hydrodynamic sizes of approx. 25 kDa and 32 kDa respectively. Glycosaminoglycan chains of the aggrecan, biglycan and decorin were treated with chondroitin ABC lyase, chondroitin AC lyase and chondroitin B lyase to determine the positions of sulphation and the degree of uronic acid epimerization. The aggrecan glycosaminoglycan chains were found to contain a 4-sulphate/6-sulphate ratio of 7:3, with no epimerization of glucuronic acid to iduronic acid. The biglycan glycosaminoglycan chains were found to contain a similar ratio of 4-sulphate/6-sulphate, but with approx. 40-45% of the glucuronic acid epimerized to iduronic acid. The decorin glycosaminoglycan chains were found to contain 4-sulphate but no detectable 6-sulphate, and approx. 30-35% epimerization of the glucuronic acid to iduronic acid. The results, using these cloned cells, indicated that a single MC615 cell is able to make all three proteoglycans with distinctive differences between the glycosaminoglycans of aggrecan, biglycan and decorin. These data indicate that a mechanism must exist for a single MC615 cell to regulate the sizes and fine structures of glycosaminoglycans on simultaneously produced, different proteoglycans in a core-protein-specific manner.

Acetylgalactosamine↗