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PubMed2002

The membrane-bound alpha-glucuronidase from Pseudomonas cellulosa hydrolyzes 4-O-methyl-D-glucuronoxylooligosaccharides but not 4-O-methyl-D-glucuronoxylan.

The microbial degradation of xylan is a key biological process. Hardwood 4-O-methyl-D-glucuronoxylans are extensively decorated with 4-O-methyl-D-glucuronic acid, which is cleaved from the polysaccharides by alpha-glucuronidases. In this report we describe the primary structures of the alpha-glucuronidase from Cellvibrio mixtus (C. mixtus GlcA67A) and the alpha-glucuronidase from Pseudomonas cellulosa (P. cellulosa GlcA67A) and characterize P. cellulosa GlcA67A. The primary structures of C. mixtus GlcA67A and P. cellulosa GlcA67A, which are 76% identical, exhibit similarities with alpha-glucuronidases in glycoside hydrolase family 67. The membrane-associated pseudomonad alpha-glucuronidase released 4-O-methyl-D-glucuronic acid from 4-O-methyl-D-glucuronoxylooligosaccharides but not from 4-O-methyl-D-glucuronoxylan. We propose that the role of the glucuronidase, in combination with cell-associated xylanases, is to hydrolyze decorated xylooligosaccharides, generated by extracellular hemicellulases, to xylose and 4-O-methyl-D-glucuronic acid, enabling the pseudomonad to preferentially utilize the sugars derived from these polymers.

Base Sequence↗
PubMed1995

Glycans and the modulation of neural-recognition molecule function.

Neural-recognition molecules are carbohydrate-bearing glycoproteins, glycolipids or proteoglycans that are found at the cell surface or in the extracellular matrix that regulate cell interactions during development, modification of synaptic activity and regeneration of nerve connections after damage in the adult. The expression of the carbohydrates appears to be fine tuned to these functions. Among the identified carbohydrates are polysialic acid, a 3'-sulfated glucuronic acid, and oligomannosidic residues. They act not only between apposing partner cell surfaces (trans-interaction) but also between recognition molecules within the surface membrane of one cell (cis-interaction), thereby forming complexes that influence transduction of signals to the cell interior.

Animals↗
PubMed1988

Preparation and characterization of antibodies against a sulfated glucuronic acid-containing glycosphingolipid.

In some patients with demyelinating neuropathy there are immunoglobulin M paraproteins that react with carbohydrate determinants shared by myelin-associated glycoprotein (MAG) and two peripheral nerve acidic glycolipids, termed sulfoglucuronosylglycosphingolipids (SGGLs). To study the antigenicity of these glycolipids, we immunized three New Zealand white rabbits with sulfoglucuronosylparagloboside (SGPG), a major SGGL in peripheral nerve, emulsified in Freund's complete adjuvant and keyhole limpet hemocyanin. All three rabbits inoculated with SGPG showed weight loss and mild weakness, predominantly in their hind feet, 2-5 weeks postinoculation (PI). Two of the three rabbits again showed moderate weakness 3 and 8 months PI, respectively. Electrophysiological studies demonstrated a slowed nerve conduction velocity in the sciatic nerve. Anti-SGPG antibody titers in sera were detected at dilutions of 1:1,000 to 1:2,500 by an enzyme-linked immunosorbent assay. Although all three rabbit sera reacted with SGGLs, two reacted with a desulfated form of SGPG and the other did not, suggesting a fine heterogeneity in antigenic specificity. As with sera from patients with demyelinative paraproteinemia, all rabbit sera reacted with MAG in human CNS and PNS myelin. They also reacted with MAG from bovine CNS myelin as well as several low-molecular-weight glycoproteins in bovine peripheral nerve myelin. Thus, we demonstrated that the rabbit antisera generated against SGPG have the same or similar antigenic specificity as those of the anti-MAG M-proteins from patients with neuropathy. The results suggest that an autoimmune response against the sulfoglucuronosyl residue may participate in the immunopathogenesis of this type of neuropathy.

Animals↗
PubMed1999

Assembly of the K40 antigen in Escherichia coli: identification of a novel enzyme responsible for addition of L-serine residues to the glycan backbone and its requirement for K40 polymerization.

Escherichia coli O8:K40 coexpresses two distinct lipopolysaccharide (LPS) structures on its surface. The O8 polysaccharide is a mannose homopolymer with a trisaccharide repeat unit and is synthesized by an ABC-2 transport-dependent pathway. The K40LPS backbone structure is composed of a trisaccharide repeating unit of N-acetylglucosamine (GlcNAc) and glucuronic acid (GlcA) and has an uncommon substitution, an L-serine moiety attached to glucuronic acid. The gene cluster responsible for synthesis of the K40 polysaccharide has previously been cloned and sequenced and was found to contain six open reading frames (ORFs) (P. A. Amor and C. Whitfield, Mol. Microbiol. 26:145-161, 1997). Here, we demonstrate that insertional inactivation of orf1 results in the accumulation of a semirough (SR)-K40LPS form which retains reactivity with specific polyclonal serum in Western immunoblots. Structural and compositional analysis of the SR-K40LPS reveals that it comprises a single K40 repeat unit attached to lipid A core. The lack of polymerization of the K40 polysaccharide indicates that orf1 encodes the K40 polymerase (Wzy) and that assembly of the K40 polysaccharide occurs via a Wzy-dependent pathway (in contrast to that of the O8 polysaccharide). Inactivation of orf3 also results in the accumulation of an SR-LPS form which fails to react with specific polyclonal K40 serum in Western immunoblots. Methylation linkage analysis and fast atom bombardment-mass spectrometry of this SR-LPS reveals that the biological repeat unit of the K40 polysaccharide is GlcNAc-GlcA-GlcNAc. Additionally, this structure lacks the L-serine substitution of GlcA. These results show that (i) orf3 encodes the enzyme responsible for the addition of the L-serine residue to the K40 backbone and (ii) substitution of individual K40 repeats with L-serine is essential for their recognition and polymerization into the K40 polysaccharide by Wzy.

Acetylglucosamine↗
PubMed1998

Endosulfan elevates testosterone biotransformation and clearance in CD-1 mice.

Toxicant-mediated induction of hepatic biotransformation enzymes is a mechanism by which endogenous steroid hormone metabolism and elimination may be altered. Endosulfan, an organochlorine insecticide that has been demonstrated to induce hepatic P450 biotransformation enzymes, was examined for its ability to alter the rate of steroid hormone metabolism in CD-1 mice. Our objective was to evaluate whether endosulfan-induced changes in the rate of testosterone metabolism were reflected in the rate of testosterone clearance and if those alterations were sufficient to disrupt steroid hormone homeostasis within the animal. Major pathways for testosterone metabolism in the liver, including hydroxylation, conjugation to glucuronic acid or sulfate, and reduction/dehydrogenation, were examined for changes due to endosulfan exposure. In female mice, endosulfan treatment elicited a dose-dependent increase in the rate of total testosterone hydroxyl metabolite formation by selectively increasing the rate of production of 16 beta-, 6 alpha, and 16 alpha-hydroxytestosterone metabolites. The hydroxylation of testosterone in the 16 beta position was most sensitive to endosulfan with a 3.3-fold increase in the rate of production of this metabolite observed following exposure to 7.5 mg/kg/day for 7 days. The rate of testosterone dehydrogenation to androstenedione was increased by 7.5 mg/kg/day of endosulfan, but the rate of direct glucuronic acid or sulfate conjugation to testosterone was not affected by any of the dosages investigated. Endosulfan was generally more toxic to male mice and did not significantly alter the rate of total hydroxytestosterone metabolite formation or glucuronic acid or sulfate conjugation. The ability of endosulfan to enhance the elimination of testosterone was, therefore, investigated in female mice. Exposure of mice to 7.5 mg/kg/day of endosulfan resulted in an approximately 3.6-fold increase in the rate of urinary elimination of [14C]androgen, but had no significant effect on the fecal elimination of [14C]androgen. The increase in androgen clearance was associated only with a small, nonsignificant decrease in serum testosterone levels. Results indicate that increases in testosterone biotransformation from endosulfan exposure can result in increases in the elimination of the steroid. However, homeostatic processes apparently compensate for the effect and minimize any consequences on serum hormone levels.

Animals↗
PubMed1987

Species differences in the metabolism of N-nitroso(2-hydroxypropyl)(2-oxopropyl)amine.

Hamsters and rats metabolize [1-14C]N-nitroso(2-hydroxypropyl)(2-oxopropyl)amine (HPOP) and N-nitrosobis(2-oxopropyl)amine (BOP) to yield N-nitrosobis(2-hydroxypropyl)-amine (BHP), glucuronic acid conjugates of HPOP and BHP, the sulfate ester of HPOP and 14C-labeled urea, all of which are excreted, and 14CO2 which is both incorporated in the urea cycle, and exhaled. The extent of metabolism and the ratios of these metabolites does not vary significantly with age or sex of the animal, however, marked species differences are evident in the metabolite composition of urine 6 h following administration of HPOP. Hamsters sulfate HPOP several times more rapidly, and reduce it to BHP more efficiently than rats. In contrast, the rat excretes more unchanged HPOP and its glucuronic acid conjugate than the hamster. Since sulfation and glucuronidation of HPOP may be involved in its activation and detoxication, these reactions were examined in detail in order to elucidate the reason(s) for their distinctively different contributions to its metabolism in rats and hamsters. Conjugation of HPOP with glucuronic acid and sulfate occurs in the livers of both rats and hamsters and is catalyzed by microsomal glucuronyl transferases and cytosolic sulfotransferases, respectively. The levels of glucuronyl transferase activity for conjugating phenolic compounds are comparable in the livers of two species; however, glucuronidation of HPOP is catalyzed by an isozyme the activity of which is three times greater in rat than in the hamster. In contrast to glucuronidation, sulfation of HPOP is catalyzed approximately 10 times faster by hamster than rat liver cytosol. Although rat liver can catalyze sulfation of phenolic compounds very effectively, it has low activity in sulfating aliphatic alcohols and beta-hydroxynitrosamines. Since both aliphatic alcohols and HPOP are sulfated by hamster liver cytosolic preparations and since these reactions are not significantly affected by the classic phenol sulfotransferase inhibitors, it appears that beta-hydroxynitrosamines may be sulfated by the aliphatic (hydroxysteroid) sulfotransferase isozymes. The failure of the rat to extensively sulfate HPOP in vivo may be attributed to the high Km of rat hydroxysteroid sulfotransferases for this compound. Of the four isomers of HPOP, only isomer A, in which the nitroso group is syn to the free keto group, is sulfated in vitro to an appreciable extent. The other three isomers either are not sulfated, or become unstable and decompose when they undergo such a reaction.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1993

[Biliary metabolites of levonorgestrel in rats].

The metabolism of levonorgestrel (LNG) in the bile following oral administration of the drug was examined in female rat. 1) Within 48 h after administration of 14C-labelled LNG (LNG-14C), 67-82% of the radioactivity was excreted into the bile. 2) Almost all the metabolites in the bile were conjugated with glucuronic acid or sulfuric acid and only a small amount of the unchanged compound was found. 3) After treatment of these metabolites in the bile with beta-glucuronidase and arylsulfatase, more than ten aglycones were detected on TLC. Three main aglycones, M1, M2 and M3, were isolated. They accounted for 68.0, 0.8 and 11.5% of the radioactivity excreted into the bile, respectively. 4) The structures of M1 and M2 were assumed to be 13-ethyl-18,19-dinor-5 alpha,17 beta-pregn-20-yne-3 alpha,17- diol and 13-ethyl-18,19-dinor-5 beta,17 beta-pregn-20-yne-3 alpha,17-diol, respectively, by NMR and LC/MS analyses, and confirmed by direct comparison with respective authentic samples. M3 was assigned to be 13-ethyl-18,19-dinor-5 alpha,17 beta-pregn-20-yne-3 alpha,16 beta,17-triol by NMR, LC/MS and GC/MS analyses and acetonide derivation. 5) Isolation of the glucuronide metabolite, M4, from the bile, was achieved by column chromatography using Amberlite XAD-2 and Sephadex LH-20. Hydrolysis of this compound with beta-glucuronidase released M1 and glucuronic acid. After M4 was converted to an acetylated-methyl ester derivative, the definite structural assignment of M4 was established to be M1-3-O-yl glucuronic acid by NMR analysis. The NOE effect and the value of the corresponding coupling constant of the anomeric proton showed that the glucoside moiety was in the beta configuration. These findings suggested that LNG was predominantly converted to 5 alpha-reduced metabolites and that the 5 beta-metabolite accounted for less than 1% of the total metabolites in female rats. These metabolites were excreted as glucuronides into the bile.

Administration, Oral↗
PubMed1983

The biotransformation of three 14C-labelled phenolic compounds in twelve species of freshwater fish.

1. The urinary and biliary excretion of 14C-labelled m-cresol, 1-naphthol and o-chlorophenol were investigated in 12 species of freshwater fish (bitterling, Rhodeus sericeus amarus; bream, Abramis brama; crucian carp, Carassius carassius; goldfish, Carassius auratus; gudgeon, Gobio gobio; guppy, Poecilia reticulata; minnow, Phoximus phoximus; perch, Perca fluviatilis; roach, Rutilus rutilus; rudd, Scardinius erythropthalmus; three-spined stickleback, Gasterosteus aculeatus; tench, Tinca tinca) when immersed in sub-lethal concentrations of the compounds in the aquarium water for 48 h. 2. The sulphate and glucuronic acid conjugates of 1-naphthol and o-chlorophenol were detected in both the aquarium water and the bile of all the fish species. 3. The oxidation product of m-cresol, m-hydroxybenzoic acid, and the sulphate conjugate of the phenol, were excreted into the aquarium water of all species except the guppy, which did not excrete m-hydroxybenzoic acid. In addition to these two metabolites, the glucuronic acid conjugate of m-cresol was found in the bile of all species, except for guppies whose small size precluded study of biliary excretion.

Animals↗
PubMed2003

Mexiletine carbonyloxy beta-D-glucuronide: a novel metabolite in human urine.

1. The study was performed to isolate and characterize a glucuronic acid conjugate of mexiletine that releases mexiletine on acid hydrolysis from urine samples obtained from healthy volunteers following a single oral dose of mexiletine. 2. The [M-H]- ion of the isolated metabolite was observed at m/z 398 in the negative electrospray ionization mass spectrum. This mass number was 44 higher than that of the product generated when mexiletine is subjected to direct glucuronidation. In positive-ion mode, collision-induced dissociation of the quasimolecular ion [M+NH4]+, m/z 417, gave product ions at m/z 224, 180 and 58. These mass spectral data indicated that the metabolite contained a carbonyloxy moiety in its structure in addition to mexiletine and a glucuronic acid moiety. 3. The presence of this carbonyloxy moiety was further supported by the following chemical reactions. When the metabolite was hydrolysed with an aqueous solution of 1 M sodium hydroxide at room temperature, mexiletine was released, whereas the N-methoxycarbonyl derivative of mexiletine was obtained after treatment of the metabolite with methanolic sodium hydroxide solution. 4. The results indicated that the structure of the isolated metabolite was the N-carbonyloxy beta-D-glucuronic acid conjugate of mexiletine.

Adult↗
PubMed1970

Partial purification and kinetics of oestriol 16 alpha-glucuronyltransferase from the cytosol fraction of human liver.

An enzyme that conjugates the 16alpha-hydroxyl group of oestriol with glucuronic acid was found in the cytosol fraction of human liver. The enzymic activity could not be sedimented when the cytosol fraction was centrifuged at 158000g(av.) for 120min. The oestriol 16alpha-glucuronyltransferase was purified 100-fold by 0-30% saturation of the cytosol fraction with ammonium sulphate followed by filtration of the precipitate through Sephadex G-200. The activity was eluted at the void volume. The product of the reaction, oestriol 16alpha-monoglucuronide, was identified by paper chromatography and by crystallization of radioactive product to constant specific radioactivity. The optimum temperature was 37 degrees C, and the activation energy was calculated to be 11.1kcal/mol. The apparent Michaelis-Menten constants for oestriol and UDP-glucuronic acid were 13.3 and 100mum respectively. Cu(2+), Zn(2+) and Hg(2+) inhibited, whereas Mg(2+), Mn(2+) and Fe(2+) stimulated the enzyme. Substrate-specificity studies indicated that the amount of oestradiol-17beta, oestradiol-17alpha and oestrone conjugated was not more than about 5% of that found for oestriol. Oestriol 16alpha-monoglucuronide, a product of the reaction, did not inhibit the 16alpha-oestriol glucuronyltransferase; in contrast, UDP, another product of the reaction, inhibited the enzyme competitively with respect to UDP-glucuronic acid as the substrate, and non-competitively with respect to oestriol as the substrate. ATP and UDP-N-acetylglucosamine did not affect the oestriol 16alpha-glucuronyltransferase. 17-Epioestriol acted as a competitive inhibitor and 16-epioestriol as a non-competitive inhibitor of the glucuronidation of oestriol. 5alpha-Pregnane-3alpha,20alpha-diol also inhibited the enzyme non-competitively. It is most likely that the oestriol 16alpha-glucuronyltransferase described here is bound to the membranes of the endoplasmic reticulum.

Adenosine Triphosphate↗
PubMed1972

Enzymic transfer of glucose and xylose from uridine diphosphate glucose and uridine diphosphate xylose to bilirubin by untreated and digitonin-activated preparations from rat liver.

1. Digitonin-treated and untreated homogenates, cell extracts and washed microsomal preparations from liver of Wistar R rats are capable of transferring sugar from UDP-glucose or UDP-xylose to bilirubin. No formation of bilirubin glycosides occurred with UDP-galactose or d-glucose, d-xylose or d-glucuronic acid as the sources of sugar. 2. Procedures to assay digitonin-activated and unactivated bilirubin UDP-glucosyltransferase and bilirubin UDP-xylosyltransferase were developed. 3. In digitonin-activated microsomal preparations the transferring enzymes had the following properties. Both enzyme activities were increased 2.5-fold by pretreatment with digitonin. They were optimum at pH6.6-7.2. Michaelis-Menten kinetics were followed with respect to UDP-glucose. In contrast, double-reciprocal plots of enzyme activity against the concentration of UDP-xylose showed two intersecting straight-line sections corresponding to concentration ranges where either bilirubin monoxyloside was formed (at low UDP-xylose concentrations) or where mixtures of both the mono- and di-xyloside were synthesized (at high UDP-xylose concentrations). Both enzyme activities were stimulated by Mg(2+); Ca(2+) was slightly less, and Mn(2+) slightly more, stimulatory than Mg(2+). Of the activities found in standard assay systems containing Mg(2+), 58-78% (substrate UDP-glucose) and 0-38% (substrate UDP-xylose) were independent of added bivalent metal ion. Double-reciprocal plots of the Mg(2+)-dependent activities against the concentration of added Mg(2+) were linear. 4. In comparative experiments the relative activities of liver homogenates obtained with UDP-glucuronic acid, UDP-glucose and UDP-xylose were 1:1.5:2.7 for untreated preparations and 1:0.29:0.44 after activation with digitonin. 5. Bilirubin UDP-glucuronyltransferase was protected against denaturation by human serum albumin, whereas bilirubin UDP-xylosyltransferase was not. 6. Digitonin-treated and untreated liver homogenates from Gunn rats were inactive in transferring sugar to bilirubin from UDP-glucuronic acid (in agreement with the work of others), UDP-glucose or UDP-xylose.

Animals↗
PubMed1994

Chemical and 13C NMR studies of Enterolobium cyclocarpum gum and its degradation products.

A structural study of the gum exudate from Enterolobium cyclocarpum has been carried out using chemical methods and 13C NMR spectroscopy. The results reveal that the structure of this gum is essentially a beta-(1-->3)-galactan. Some galactoses are 6-O-linked and others also occur as terminal residues. There is evidence that supports the presence of alpha-L-arabinofuranose and beta-L-arabinopyranose. beta-D-Glucuronic acid may be present as terminal and internal residues, while the 4-O-methyl-alpha-D-glucuronic acid residues exist predominantly in internal positions.

Arabinose↗
PubMed1976

Structural investigations of the extracellular polysaccharide elaborated by S19, a Xanthomonas-type bacterium.

The extracellular, acidic heteropolysaccharide from Xanthomonas S19 consists of D-glucuronic acid, D-glucose, D-galactose, and D-mannose residues in the approximate molar ratios of 1.6:3:1:1, plus acetyl groups linked to C-2 and/or C-3 of a large proportion of the glucose residues. Methylation studies showed that the glucose is present as non-reducing end-group also as 1,2- and 1,4-linked units, the galactose residues are solely 1,3-linked, a major proportion of the mannose residues are 1,2,4-linked and the rest 1,2-linked. A high proportion of the glucuronic acid units are 1,4-linked. Periodate oxidation confirmed the presence of these linkages. The disaccharides D-Glc-(1 leads to 4)-D-Glc, D-Glc-(1 leads to 2)-D-Man, D-Glc-(1 leads to 3)-D-Gal, D-Gal(1 leads to 2)-D-Glc, D-GlcA-(1 leads to 4)-D-GlcA, and beta-D-GlcA-(1 leads to 4)-D-Man were isolated from a partial hydrolysate of the polysaccharide, and characterised. The similarities and differences between this polysaccharide and those from other Xanthomonas species are discussed.

Galactose↗
PubMed1985

Metabolism and enterohepatic circulation of benzo(a)pyrene-4,5-epoxide in the rat.

After i.v. administration of 3H-benzo(a)pyrene-4,5-epoxide (32.5 mumol/kg) to rats, 76% of the 3H appeared in bile within 3 h. The glutathione conjugate of benzo(a)pyrene-4,5-epoxide was the major biliary metabolite (33% of dose), together with a glucuronic acid conjugate of benzo(a)pyrene-4,5-diol (18%) and an unidentified metabolite (10%). The glutathione and glucuronic acid conjugates both undergo extensive enterohepatic circulation. Thus, following the intraduodenal administration of the 3H-labelled conjugates, 26% of the radioactivity was excreted in the bile after 24 h in the case of the glutathione derivative, and 40% in the case of the glucuronide. The benzo(a)pyrene-4,5-diol glucuronide, on enterohepatic circulation, appears in the bile in the same form as the conjugate administered with no evidence of further metabolism of the polycyclic hydrocarbon moiety. The glutathione conjugate of benzo(a)pyrene-4,5-epoxide, on recirculation, is reexcreted in bile as one unidentified metabolite, which is susceptible to the action of arylsulphatase.

Animals↗
PubMed1985

Effects of butylated hydroxyanisole on hepatic glucuronidation capacity in mice.

The present study has examined biochemical mechanisms by which butylated hydroxyanisole (BHA) increases the glucuronidation of xenobiotics. Male and female Swiss Webster mice received BHA in the diet (1% w/w) for 10 days (600 to 800 mg/kg/day). Hepatic UDP-glucuronosyltransferase activities were increased toward specific substrates in native and detergent-activated microsomes. In general, BHA increased glucuronidation toward group 1 substrates (1-naphthol and 4-nitrophenol) 36 to 141% whereas no changes were found with a group 2 (chloramphenicol) or a group 3 substrate (digitoxigenin monodigitoxoside). Also, activities toward unclassified substrates (estrone, acetaminophen, and diethylstilbestrol) were increased (29 to 139%) by BHA. BHA treatment also increased hepatic UDP-glucuronic acid content (two- to threefold) by increasing UDP-glucose concentration (30 to 50%) and enhancing UDP-glucose dehydrogenase activity (300 to 400%). BHA had a more pronounced effect in female than male mice when data were expressed as activity or amount per liver because BHA treatment selectively increased the liver weight in female mice. In conclusion, BHA increases the capacity for glucuronidation in mice by elevating both UDP-glucuronosyltransferase activities and UDP-glucuronic acid concentration in liver.

Animals↗
PubMed1992

Structural studies of an emulsion-stabilizing exopolysaccharide produced by an adhesive, hydrophobic Rhodococcus strain.

The primary structure of an emulsion-stabilizing exopolysaccharide from the adhesive, hydrophobic Rhodococcus strain No. 33 was elucidated by NMR spectroscopy, methylation analyses, periodate oxidation and oligosaccharide analyses. The polysaccharide PS-33 consisted of rhamnose, galactose, glucose and glucuronic acid in molar ratios of 2:1:1:1. The main chain contained 3-substituted alpha-D-glucuronic acid linked to the 3-position at alpha-L-rhamnose, in addition to 3-substituted residues of beta-D-galactose and alpha-D-glucose. The alpha-L-rhamnose of the side chain was linked to position 4 of the galactose. In addition, the polysaccharide was O-acetylated, corresponding to one acetyl group per repeating unit. From the results two structural possibilities could be suggested. As the polysaccharide carries hydrophobic groups (methyl of rhamnose/O-acetyl), it is very likely that these are of general significance for the emulsifying activity of polysaccharides. It also seems to be possible that this polysaccharide is at least partially responsible for the hydrophobic cell surface properties of the Rhodococcus strain No. 33 and it may be involved in hydrophobic interactions when adhering to hydrophobic interfaces.

Bacterial Adhesion↗
PubMed2004

Venous and arterial thrombosis in rat models: dissociation of the antithrombotic effects of glycosaminoglycans.

Fucosylated chondroitin sulfate is a glycosaminoglycan from sea cucumber, made up of alternating beta-D-glucuronic acid and N-acetyl-beta-D-galactosamine units, like mammalian chondroitin sulfate. But the beta-D-glucuronic acid residues have branches of sulfated fucose, which confer high anticoagulant and antithrombotic properties on this compound. We have now compared the anticoagulant, bleeding and antithrombotic effects of this fucosylated chondroitin sulfate and its carboxyl-reduced derivative. Both compounds have similar anticoagulant action, mostly due to acceleration of thrombin inhibition in the presence of heparin cofactor II. The native glycosaminoglycan shows a correlation among anticoagulant, bleeding and antithrombotic effects. Inhibition of thrombosis in an arterio-venous shunt occurs at low doses, which are almost ineffective in modifying the anticoagulant activity of plasma. In a venous experimental model, on the contrary, antithrombotic activity requires high doses and occurs concomitantly with an increase in the anticoagulant activity of plasma. The action of fucosylated chondroitin sulfate on thrombosis is apparently unrelated to its effect on platelet aggregation. The carboxyl-reduced derivative of fucosylated chondroitin sulfate prevented thrombosis in the arterio-venous shunt, but not in the venous experimental model. This derivative did not increase bleeding, in spite of its potent anticoagulant activity. Therefore, our results reveal a dissociation of the anticoagulant, bleeding and antithrombotic effects of the glycosaminoglycan. Furthermore, we demonstrate that a polysaccharide may be a potent inhibitor of one type of thrombotic episode, but inactive on another. We propose that the different effects of fucosylated chondroitin sulfate and its carboxyl-reduced derivative on venous thrombosis may be related to adherence of the glycosaminoglycan to the vessel wall.

Acetylgalactosamine↗