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PubMed1983

D-Glucosamine-induced increase of the glycerol-containing lipids in growing cultures of human malignant epithelial cells.

D-Glucosamine was found to inhibit the growth of human malignant epithelial cells SW-839, HT-29, RT-4, and SK-OV-3 in culture in a process that was associated with significant increments in glycerol-containing lipids. Each cell line had a different sensitivity to the drug, but all four cell lines shared the same features in their response, i.e., dose-dependent (at concentrations of 1, 5, and 10 mM), noncytotoxic reductions in growth (minimum 30%, maximum 70%), and simultaneous 1.5-fold to sevenfold increases in lipid contents. Cells regained their normal growth and lipid patterns when glucosamine was removed. Glucosamine did not modify the lipid contents of cells in the late phase of culture when growth was minimal.

Adenocarcinoma↗

PubMed1983

Studies on the cornea. X. Incorporation of 14C-glucosamine into glycosaminoglycans and glycoproteins of elasmobranch corneas, extractability of these components and morphological effects of such extractions.

Incorporation of 14C-glucosamine into dogfish (Squalus acanthias) corneas occurs primarily in the glycosaminoglycans (GAG) and glycoproteins (GP) extractable with elasmobranch Ringer's solution but the rate at which this component can be extracted varies inversely with the age (size) of the fish. Whereas this fraction represents only one-fourth of the total hexosamine (Hex-N) it contains nearly three-fourths of the newly incorporated 14C-glucosamine. The CaCl2-extractable HexN contains only 13% of the incorporated radioactivity. Collagen-associated GAG in both soluble and insoluble collagen fractions contain keratan sulfate, dermatan sulfate and chondroitin-4-sulfate, with the GAG associated with the salt-insoluble collagen having only half the radioactivity of those associated with the soluble fraction. However, the specific activities of both the salt-insoluble and the salt-soluble fractions were very low, suggesting that the GAG-GP which are tightly bound to collagen may have a high degree of stability. Partially de-epithelialized corneas incorporated 14C-glucosamine at rates ranging from 22% to 58% of the efficiency of intact corneas, suggesting a possibly significant role of the epithelium in the biosynthesis of GAG-GP in the adult dogfish. Morphologic results exactly paralleled those previously reported by us for the bovine cornea with the exception that the effects of CaCl2 extraction of GAG-GP were not evident on the collagen fibers until the second to fifth sequential CaCl2 extraction. The morphologic findings, therefore, exactly parallel the analytic findings which show that a significant portion of the collagen and collagen-associated GAG-GP of the dogfish cornea remains after the double extraction. How much of this remaining material represents sutural fibers and their associated GAG-GP is yet to be determined.

Animals↗

PubMed1983

Localization fo 3H-glucosamine and 35S-sulfate in the hamster retina--light and electron microscopic autoradiography.

The localization of 3H-glucosamine and 35S-sulfate in the hamster retina was studied by light and electron microscopic autoradiography. Exposed silver grains were concentrated in the nerve fiber, inner plexiform, outer plexiform and inner segment layers. The heaviest labeling was observed over the inner segment layer in the glucosamine experiment and over the nerve fiber layers in the sulfate experiment. Specimens from 12- and 16-day-old hamsters showed slightly heavier labeling than did those from adult animals. In the electron microscopic autoradiography using 3H-glucosamine, grains were initially associated with the retinal pigment epithelium, the inner segment and the Müller cell and were subsequently displaced into the spaces between the retinal pigment epithelium and the other segment and into the nerve fiber layers. The labelled sulfates in the electron microscopic autoradiography were seen in the nerve fiber, plexiform and photoreceptor layers. These data indicate that glycosaminoglycans may be synthesized in the retinal pigment epithelium, the inner segment and the Müller cell.

Animals↗

PubMed1981

Interference of glucosamine and other aminosugars on blast transformation.

The effect of exogenous glucosamine and other aminosugars on the incorporation of 3H-leucine 3H-uridine and 3H-thymidine into mitogen induced lymphocytes was studied. D-glucosamine D-galactosamine and D-mannosamine inhibit the incorporation of these precursors into protein. RNA and DNA of blast cells. Glucose and pyruvate did not reverse this inhibition. Glucosamine - 6P, acetylglucosamine and acetylglucosamine and have shown a considerably lower inhibition in the uptake of these labeled precursors.

Glucosamine↗

PubMed1994

In vitro uptake and incorporation of [3H]glucosamine and [3H]leucine by Plagiorchis elegans metacercariae.

We examined the ability of Plagiorchis elegans metacercariae to take up [3H]glucosamine and [3H]leucine in vitro and incorporate these precursors into parasite tissues at various times in their development. Uptake of both precursors was greater by young metacercariae (< or = 8 hr postinfection [PI]) than old metacercariae (> 8 hr PI). Virtually all [3H]glucosamine was incorporated into juvenile worms, whereas only small amounts of [3H]leucine were incorporated into both juvenile worms and cyst walls. [3H]glucosamine was incorporated into a variety of proteins by 2-hr- and 5-day-old metacercariae as determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis and fluorography. There was evidence of developmentally regulated or stage-specific expression of 14-, 19.5-, and 37-kDa proteins by older metacercariae. These results suggest a differential incorporation of nutrients procured from the insect host into parasite tissues by metacercariae of different ages over the course of their development.

Animals↗

PubMed1977

The inhibition of thymidine metabolism in tumor cells treated with D-glucosamine.

The amino sugar, D-glucosamine, inhibits the preformed route of thymidine metabolism in rat C6 glioma cells. This inhibition results from a concatenation of several distinct effects, including the inhibition of thymidine uptake, the reduction of thymidine phosphorylation, and an increased leakage of thymidine to the extracellular space. Each of these effects, while ostensibly small in magnitude, is significant and contributes to the observed inhibition of acid-precipitable thymidine incorporation by D-glucosamine. These effects of D-glucosamine, together with its known ability to reduce uridine nucleotide pools, may contribute to its toxicity toward certain experimental animal tumors.

Cell Line↗

PubMed1996

[The efficacy and safety of glucosamine sulfate in the treatment of gonarthritis].

This study was performed to evaluate the therapeutic efficacy and tolerability of glucosamine sulfate in patients with gonarthritis. During the 12-month study period, the signs and symptoms of the disease were evaluated, as well as the dosage of the urinary pyridinoline. In this trial, we demonstrated that glucosamine sulfate has a chondroprotective activity, which was significant after the first 3 months of therapy. Moreover, this study showed that the side effects due to glucosamine sulfate were mild to moderate and did not require discontinuation of the drug.

Adult↗

PubMedDate not supplied

Conservative management of spinal osteoarthritis with glucosamine sulfate and chiropractic treatment.

OBJECTIVE: To evaluate the rationale behind the most commonly used treatments of osteoarthritis, including nonsteroidal anti-inflammatory drugs (NSAIDs), and to assess more effective conservative treatment options. SUMMARY OF BACKGROUND DATA: This review includes a description of the pathophysiology and prevalence of osteoarthritis, joint physiology and NSAID treatment of osteoarthritis, as well as side effects on joints, the gastrointestinal tract, kidneys and livers. Several studies of conservative treatment, consisting of supplementation of glucosamine sulfate (which occurs naturally in the human body), exercise, and the use of chiropractic treatment for maintaining joint function and preventing further destruction, are reviewed. DATA SOURCES: A computerized search of Medline using the key indexing terms osteoarthritis, degenerative joint disease, nonsteroidal anti-inflammatory drugs, glucosamine sulfate, chiropractic and manipulation. RESULTS: Numerous studies wee obtained under each subheading and reviewed by category. Human and animal-model studies are described. CONCLUSION: The rationales for using NSAIDs in the treatment of osteoarthritis is controversial and openly contested. Given the detrimental effects of NSAIDs on joints and other organs, their use should be discouraged and their classification as a first choice conservative treatment should be abolished. A truly effective and conservative approach to the treatment of osteoarthritis should include chiropractic manipulation, essential nutrient supplementation, exogenous administration of glucosamine sulfate and rehabilitative stretches and exercises to maintain joint function. Because there is no correlation between pain levels and the extent of degeneration detected by radiographic or physical examination, conservative treatment should be initiated and sustained based on functional, objective findings and not strictly on how the patient feels. The use of NSAIDs should be limited to the treatment of gross inflammation and analgesics should only be used in the short-term when absolutely necessary for pain palliation. The present conservative approach could lead not only to a better quality of life but also to the saving of health care dollars by reducing the iatrogenic morbidity and mortality associated with NSAID use.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed1998

Glucosamine in serum of patients after myocardial infarction subjected to rehabilitation training.

This paper presents results of 3 weeks physical training on glucosamine level in serum of male patients after myocardial infarction (MI) aged between 38 and 61. Patients were randomised in two groups: the training group (n = 21), staying in Cardiac Rehabilitation Department and the control group (n = 11), discharged home for 3 weeks. Each group received identical dietary instructions. The training group performed exercises every day: on bicycle ergometer during 30 minutes (5 times a week), overall-conditioning exercises for 30 minutes daily and 30 to 60 minutes of walking each day. Before administering of the therapy and 3 weeks later all MI patients performed the bicycle ergometer exercise test until the ventilatory threshold was reached. Before that test and 3 minutes after its termination capillary and venous blood samples were drawn. In the capillary blood samples indices of acid-base balance, lactate level, and glucose level were determined. In venous blood samples the serum levels of immunoreactive insulin, C-peptide and glucosamine were determined as well as binding of 125I-insulin to erythrocyte receptors. Obtained results show that administered therapy increased physical fitness and decreased of glucosamine concentration, insulinaemia and insulin resistance.

Adult↗

PubMed2004

Comparison of structural and hemostatic properties of the poly-N-acetyl glucosamine Syvek Patch with products containing chitosan.

Polysaccharides are becoming increasingly developed as therapeutics and medical products, as the new field of Glycomics expands. Glycosaminoglycans that contain N-acetyl glucosamine constituents have been the focus of research leading to medical devices. A new hemostatic bandage, the Syvek Patch, has been introduced in the recent past for the control of bleeding at vascular access sites in interventional cardiology and radiology procedures. This product consists of poly-N-acetyl glucosamine (pGlcNAc) isolated in a unique fiber crystalline structural form from the large-scale culture and processing of a marine diatom. The Syvek pGlcNAc fiber material has chemical, physical, and biological properties that result in its favorable performance as a hemostat. Two new products, the Clo-Sur PAD and ChitoSeal, have recently become available also as patch hemostats. These two products both use chitosan, another N-acetyl glucosamine containing glycosaminoglycan, as their active ingredient. Structural, chemical, and biological comparisons of Syvek pGlcNAc and chitosan reveal a number of important differences. Syvek pGlcNAc fibers contain approximately 50 fully acetylated, high molecular weight pGlcNAc molecules in a crystalline, three-dimensional beta structure array, and are insoluble. Chitosan is a low molecular weight mixed amorphous cationic polymer with no regular structure as a solid, and is water-soluble taking on a random coil configuration when in solution. These structural dissimilarities result in differences in the hemostatic properties of the two materials. Syvek pGlcNAc is able to significantly reduce the in vitro fibrin clot formation time of platelet-rich plasma samples and has the ability to cause aggregation of red blood cells in vitro. Chitosan is no better than gauze or other controls in these in vitro assays. The Syvek Patch is able to control the bleeding and cause hemostasis in a coagulopathic swine spleen-bleeding animal model 100% of the time, whereas Clo-Sur PAD was completely unsuccessful (0%) and ChitoSeal (25%) was worse than a gauze pad control (50%) in the same model. Syvek pGlcNAc fibers have structural and chemical properties that provide a unique basis for their ability to interact with blood components to cause hemostasis. Chitosan does not have the same properties and capabilities.

Acetylglucosamine↗

PubMed1995

Epitope mapping and tight-binding inhibition with monoclonal antibodies directed against Escherichia coli glucosamine 6-phosphate synthase.

In the present work, we attempt to identify inhibitory monoclonal antibodies directed against Escherichia coli glucosamine-6P synthase (GlmS) and to localize the corresponding epitopes to better understand the topology of the enzyme during catalysis. Four of the 15 monoclonal antibodies have been shown to be specific for the native form of the enzyme and 2 of them, 505.1 and 522.2, strongly inhibit the glucosamine synthase activity. Kinetic analysis of 505.1 antibody behavior revealed a tight-binding inhibition with a Ki = 40 +/- 20 pM, a value which is four orders of magnitude lower than the best active site-directed inhibitor reported so far. The reactivity of all the monoclonal antibodies with 601 overlapping octapeptides covering the entire sequence of GlmS was tested by enzyme-linked immunosorbent assay for precise epitope mapping. Four linear epitopes specific for the denatured protein and one present in both native and denatured enzyme were defined by this approach. Neither 505.1 nor 522.2 was directed against linear epitopes. However, evidence for the binding of 505.1 at the glutamine catalytic site was shown by using site-directed mutants of GlmS as well as by competition experiments with an irreversible inhibitor. The mAb 105.1, which recognizes the octapeptide containing the sequence RWATHG conserved among the six glucosamine-6P synthases reported so far, allowed the detection of the human enzyme.

Amino Acid Sequence↗

PubMed1996

Giardia lamblia: increased UDP-N-acetyl-D-glucosamine and N-acetyl-D-galactosamine transferase activities during encystation.

The cyst wall of Giardia lamblia is essential for survival of the parasite outside the host. N-acetyl-D-glucosamine (GalNAc) has been reported as a major terminal sugar of cyst wall glycoproteins and N-acetyl-D-galactosamine (GalNAc) as the major sugar of the fibrous insoluble cyst wall fraction. Therefore, we measured UDP-glycosyltransferase activities as the incorporation of [3H]UDP-sugar into an alcohol-insoluble product. We found that during encystation only UDP-GlcNAc and UDP-GalNAc transferase (UDP-GT) activities increased approximately three- to five-fold compared to nonencysting trophozoites. These activities were distributed approximately equally in the pellet and soluble fractions. The apparent K(m) and V(max) of UDP-GT in these fractions were similar. The activities from both fractions were dependent on Mn2+; however, the pellet enzymes were also partially activated by other metal ions. Both pUDP-GT and sUDP-GT were inhibited by uridine, UDP, and UDP sugars, but not by GlcNAc or GalNAc. Isolation and analysis of the reaction products suggest that pUDP-GT incorporate GlcNAc and GalNAc into glycoproteins, since the products were proteinase sensitive. In contrast, sUDP-GT products were resistant to proteinase treatment. Hydrolysis of the product of UDP-GlcNAc-T incorporation by trifluoroacetic acid released only glucosamine, while both glucosamine and galactosamine were released from UDP-GalNAc-T products, supporting the presence of an epimerase in Giardia which can convert GalNAc to GlcNAc during incorporation. This study suggests that at least two UDP-GT activities are induced during encystation, which are responsible for the transfer of GlcNAc and GalNAc from UDP-GlcNAc or UDP-GalNAc into both proteinase-sensitive and proteinase-resistant components of the Giardia cyst wall.

Animals↗

PubMed1991

Six nodulation genes of nod box locus 4 in Rhizobium meliloti are involved in nodulation signal production: nodM codes for D-glucosamine synthetase.

The nucleotide sequence of the nod box locus n4 in Rhizobium meliloti was determined and revealed six genes organized in a single transcriptional unit, which are induced in response to a plant signal such as luteolin. Mutations in these genes influence the early steps of nodule development on Medicago, but have no detectable effect on Melilotus, another host for R. meliloti. Based on sequence homology, the first open reading frame (ORF) corresponds to the nodM gene and the last to the nodN gene of Rhizobium leguminosarum. The others do not exhibit similarity to any genes sequenced so far, so we designated them as nolF, nolG, nolH and nolI, respectively. We found that the n4 locus, and especially the nodM and nodN genes, are involved in the production of the root hair deformation (Had) factor. NodM exhibits homology to amidotransferases, primarily to the D-glucosamine synthetase encoded by the glmS gene of Escherichia coli. We demonstrated that in E. coli the regulatory gene nodD together with luteolin can activate nod genes. On this basis we showed that nodM complemented an E. coli glmS- mutation, indicating that nodM can be considered as a glmS gene under plant signal control. Moreover, exogenously supplied D-glucosamine restored nodulation of Medicago by nodM mutants. Our data suggest that in addition to the housekeeping glmS gene of R. melioti, nodM as a second glmS copy provides glucosamine in sufficient amounts for the synthesis of the Had factor.

Amino Acid Sequence↗

PubMed1989

A theoretical study of glucosamine synthase. Part I. Molecular mechanics calculations on substrate binding.

Glucosamine synthase transfers the gamma-amino group of glutamine to fructose, producing 1-glucosamine which is the key constituent of bacterial and fungal cell walls. In this study, model calculations were performed on substrate binding to the enzyme active site. Two models of the active site of glucosamine synthase were proposed, which assume two different sequences of aminoacids, Cys-Gly-Ile and Cys-Ala-Cys, the first one being the N-terminal sequence of the Escherichia coli enzyme. Several initial geometries were assumed for these tripeptides, the energy was then optimized by means of molecular mechanics. It has been found that the structure which is both energy optimal and satisfies the assumed cysteine sulphur arrangement consists of combinations of C7eq and C7ax conformations of single residues. Molecular mechanics calculations were then performed on glutamine and D-fructose-6-phosphate, which are the substrates of the enzymatic catalysis, and on their complex with the enzyme glutamine-binding site. The spatial configuration of the compounds under study, which is optimal as far as the reaction path is concerned, also turned out to be an energy minimum.

Alanine↗

PubMed1990

Isolation of a crustacean N-acetyl-D-glucosamine-1-phosphate transferase and its activation by phospholipids.

The N-acetyl-D-glucosamine-1-phosphate:dolichol phosphate transferase from Artemia has been partially purified and characterized. The enzyme is solubilized from crude microsomes using Triton X-100, and after detergent removal appears to be associated with phospholipids. Using dolichol phosphate and UDP-N-acetyl-D-glucosamine as substrates, the enzyme catalyzes the formation of dolichol-pyrophosphate-N-acetyl-D-glucosamine. The product identity has been verified by TLC and paper chromatography following mild acid hydrolysis. Under the incubation conditions used only one product is made, i.e., Dol-P-P-GlcNAc. The formation of product is linear with increasing amounts of added protein and with time of incubation. The enzyme requires magnesium ions for activity. Activity of the enzyme is stimulated 6-fold by exogenous dolichol phosphate and is also stimulated by added phospholipids, with optimal activity being obtained in the presence of mixtures of phosphatidylcholine and phosphatidylglycerol. Enzymatic activity is not increased upon addition of GDP-mannose or dolichol phosphate mannose. The enzyme is rapidly inactivated by exposure to several detergents, including Triton X-100 and deoxycholate. The activity is inhibited by tunicamycin and by the purified B2 homologue of this antibiotic. Other antibiotic inhibitors such as diumycin and polyoxin D have little effect on the enzyme. Both the microsomal and solubilized enzyme preparations are inactivated by 70% upon treatment with phospholipase A2; activity may be restored by addition of phospholipids. Following hydrophobic interaction chromatography on Phenyl Sepharose, gel filtration chromatography on Sepharose CL-4B indicated that the enzyme, purified 81-fold, contained phophatidylcholine and phosphatidyl-ethanolamine.

Animals↗

PubMed1986

Inactivation of glucosamine-6-phosphate synthetase from Salmonella typhimurium LT2 by fumaroyl diaminopropanoic acid derivatives, a novel group of glutamine analogs.

A novel group of glutamine analogs, N3-fumaroyl-L-2,3-diaminopropanoic acid (FDP) and its derivatives and analogs including amide (FCDP), methyl ester (FMDP) and its homologue, N4-(4-methoxyfumaroyl)-L-2,4-diaminobutanoic acid, inactivate glucosamine-6-phosphate synthetase (L-glutamine: D-fructose-6-phosphate aminotransferase (hexose-isomerizing), EC 2.6.1.16), isolated from Salmonella typhimurium, by covalent modification. For comparative purposes, selected known glutamine analogs were also examined. Anticapsin, 6-diazo-5-oxo-L-norleucine and, at high concentration, azaserine inactivate the enzyme. The pseudo-first-order rate constants show a hyperbolic dependence on inhibitor concentration for all the above-mentioned inhibitors, suggesting the formation of a reversible complex prior to covalent modification. Dissociation constants for inhibitors were determined and ranged from 10(-4) M for FCDP to 10(-6) M for FMDP. Albizziin, gamma-glutamylhydroxamate and, at low concentration, azaserine inhibit glucosamine synthetase only reversibly. All inhibitors tested are competitive in relation to glutamine. and competitive inhibitors, albizziin and gamma-glutamylhydroxamate protect the enzyme against inactivation. Fructose 6-phosphate accelerates the rate of inactivation. Some analogs of FDP, such as SMDP, CRDP, O-FMSer, MMDP and AADP, are not active against glucosamine-6-phosphate synthetase. The structure-activity relationship of the novel group of glutamine analogs is discussed and structural requirements for the activity of these compounds is established. It is postulated that the compounds examined can be classified as mechanism-based enzyme inactivators.

Alanine↗

PubMed2005

Glucosamine induces lipid accumulation and adipogenic change in C2C12 myoblasts.

Hyperglycemia-induced activation of hexosamine biosynthesis pathway (HBP) has been implicated in the development of insulin resistance in skeletal muscles. In the present study, the content of uridine-5'-diphospho-N-acetylglucosamine, the end product of the HBP, was elevated in skeletal muscle of obese diabetic KKA(y) mice, compared with control mice. To elucidate the effect of elevated HBP in the skeletal muscle, we treated C2C12 myoblasts with glucosamine, an intermediate metabolite of the HBP. Glucosamine induced lipid accumulation and significantly increased the mRNA expression levels of peroxisome proliferator-activated receptor gamma, adiponectin, and aP2 in C2C12 myoblasts. Similar mRNA changes were observed in skeletal muscles of Sprague-Dawley rats treated with glucosamine infusion. Our results provide a possible explanation of hyperglycemia-induced insulin resistance in skeletal muscle.

Adipocytes↗

PubMed2005

In situ formation of C-glycosides during electrospray ionization tandem mass spectrometry of a series of synthetic amphiphilic cholesteryl polyethoxy neoglycolipids containing N-acetyl-D-glucosamine.

In this communication, the structural analysis of six synthetic O-Linked amphiphilic cholesteryl polyethoxy neoglycolipids containing N-acetyl-D-glucosamine was performed by electrospray ionization mass spectrometry in the positive ion mode, with a QqTOF-MS/MS hybrid instrument. The MS/MS analyses provided evidence for the "in situ" formation, in the collision cell of the tandem mass spectrometer, of an unexpected and unique [C-glycoside]+ product ion, resulting from an ion-molecule reaction between the N-acetyl-D-glucosamine oxonium ion and the neutral cholesta-3,5-diene molecule. Quasi MS3 analysis of this ion resulted in the dissociation of the precursor [C-glycoside]+ ion, which produced the expected third generation N-acetyl-D-glucosamine oxonium and the protonated cholesta-3,5-diene product ions.

Acetylglucosamine↗