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PubMed1979

Differences in the incorporation of [3H]-glucosamine into nascent polypeptide chains on free polysomes and two fractions of membrane-bound polysomes in mouse myeloma cells.

The incorporation of [3H]-glucosamine into polypeptides of three fractions of polysomes in MPC-11 cells was studied. After short term incubation greatest incorporation was observed in a fraction of membrane-bound polysomes, which after nitrogen cavitation of cells, remained bound to the endoplasmic reticulum (ER) associated with the nucleus (fraction 2). Polypeptide chains on membrane-bound polysomes in the microsomal fraction (fraction 1) and free polysomes contained much less radioactivity. Since nascent polypeptide chains contained within membrane-bound polysomes of fraction 2 are glycosylated at an earlier stage than those in fraction 1 it is likely that this represents a difference in type of proteins synthesized in the respective fractions of ER.

Cell Line↗
PubMed1980

Intracellular glycosylation of influenza hemagglutinin: the effect of glucosamine.

The intracellular glycosylation of influenza virus hemagglutinin has been studied in calf kidney primary cultures infected with influenza virus A/NWS (H0N1). Intermediate glycosylated forms were obtained by the addition of glucosamine to the culture medium; they were characterized after [35S]-methionine labelling by their precursor relationship, by immunoprecipitation and peptide mapping. The underglycosylated hemagglutinins were distributed in classes of discrete molecular weight indicating that glycosylation occurred in a stepwise manner. A total of 8 different bands, suggesting 7 glycosylation sites, was obtained under conditions of both complete and incomplete glycosylation.

Animals↗
PubMed1976

In vivo antiviral activity of D-glucosamine.

Intraperitoneal treatments with D-glucosamine, an inhibitor of the glycosylation of the viral envelope, decreased the growth rate of tumors induced in quails or in chicks by Rous sarcoma virus and increased the survival of mice inoculated with human influenza virus.

Animals↗
PubMed1987

The effect of D-(+)-glucosamine on levels of free N-acetylneuraminic acid and UDP-N-acetylhexosamines in infantile sialic acid storage disease (ISSD) fibroblasts.

An impairment in the regulation of N-acetylneuraminic acid (NANA) biosynthesis might potentially contribute to accumulation of free NANA in fibroblasts of patients with sialic acid storage disease (ISSD). By the use of a glucosamine loading test an increase in uridine-diphosphate-N-acetyl-hexosamines (UDP-HexNAc) but not in free NANA was found. NANA biosynthesis therefore appears to be under normal regulatory control in ISSD.

Fibroblasts↗
PubMed1989

Glucosamine enhanced sperm-egg binding but inhibited sperm-egg fusion in mouse.

In order to study the sperm-egg recognition mechanism on the surface of the plasma membrane, zonae were removed from mouse eggs by exposure to acidic conditions. Sperm binding to denuded eggs was then observed in the presence of various sugars. Among several carbohydrates tested, only glucosamine (GlcN) was found to increase the number of sperm bound to eggs while inhibiting sperm-egg fusion. The inhibition was reversible; when denuded eggs were transferred to a GlcN free medium, a high rate of polyspermy was observed.

Animals↗
PubMed1985

Incorporation of (35S)sulfate and (3H)glucosamine into glycoaminoglycans in rat incisor predentine and dentine: comparison by autoradiography of fixation by rapid-freezing, freeze-substitution, and aldehyde fixation.

At 4 and 24 hours after injection of (35S)sulfate, there were 22-67% fewer silver grains on conventionally fixed sections than on sections fixed by cryotechniques. Differences were smaller when (3H) glucosamine was chosen as precursor. The number of silver grains increased between 4 and 24 hours in predentine and in a 30-micron band of dentine that had already undergone mineralization. Only a few grains were observed, however, in the 5-micron dentine band located at the mineralization front. This suggests that glycoaminoglycans, which in predentine have a space-filling role, facilitate transport and diffusion and inhibit mineralization, may limit crystal growth in dentine once a certain degree of apatite formation has been reached. All these properties are correlated with the structural and functional properties of the tissues.

Aldehydes↗
PubMedDate not supplied

Incorporation of labeled glucosamine into glycoproteins by organ cultures of hamster trachea: adverse effects of HEPES buffer.

Hamster tracheas were cultured in serum-free CMRL 1066 medium buffered with either NaHCO3 alone or HEPES (N-2-hydroxyethylpiperazine-N'-2-ethanesulphonic acid) plus NaHCO3 in an atmosphere of 95% O2 and 5% CO2. Afther 2 days in culture, tracheas maintained in HEPES plus NaHCO3-buffered medium showed an altered surface morphology. Histiological examination after 6 days of culture with HEPES plus NaHCO3 showed the presence of only scattered clumps of cilia. Incorporation of [14C]-glucosamine into intracellular glycoproteins was reduced by 75% and into secreted glycoproteins by 54% in cultures buffered with HEPES plus NaHCO3, compared to NaHCO3-buffered cultures. Incorporation of [H]fucose into intracellular glycoproteins was also reduced, although no effect was observed on secreted glycoproteins.

Animals↗
PubMed1977

Characterization of human malignant melanoma cell lines. VII. Glycoprotein synthesis and shedding as revealed by [3H]glucosamine labeling.

We have established conditions for the study of membrane glycoprotein synthesis and turnover in cultured human malignant melanoma cell lines using the labeled precursor [3H]glucosamine. Uptake of label increased parallel with cell growth, reaching a steady state in resting cultures. Fifteen to 30% of incorporated label can be released from the cells by trypsin treatment depending on the conditions of exposure to the enzyme, and about 50% of the incorporated label is spontaneously shed from the cells within 96 hr of incubation. Labeling in exhausted medium gave a 5- to 8-fold increase in uptake which was inhibited by addition of glucose (2 mg per ml) into the culture medium. The percentage of trypsin-releasable material was identical in fresh and exhausted medium; however, the percentage shed was less in cells initially labeled in exhausted medium. These data provide background information for further studies on the antigenic composition of the glycoproteins of cultured melanoma cells.

Cell Division↗
PubMed1975

Prevention of cell agglutination and competence in a genetically transformable strain of Pneumococcus by D-glucosamine and D-galactosamine.

In the presence of amino sugars D-glucosamine and D-galactosamine no spontaneous competence could be observed in the highly transformable R6bd strain of Pneumococcus or it was decreased by several orders of magnitude. The highest inhibition of competence was detected when the amino sugar at a concentration 5 mg/ml of the medium was added not only to the transformation but also to the pretransformation medium. After a 150 min growth in the transformation medium in the presence of the amino sugar a 3--4-fold greater number of cells (as a viable count) could be detected as compared with the control without the amino sugar. It was found microscopically that the amino sugar prevents natural agglutination, which normally occurs in the competent culture. The role of specific amino sugar determinants for binding of the competence factor on the cell surface and the resulting inhibitory effect of these sugars on the development of competence are discussed.

Agglutination↗
PubMed2005

Fursultiamine, a vitamin B1 derivative, enhances chondroprotective effects of glucosamine hydrochloride and chondroitin sulfate in rabbit experimental osteoarthritis.

OBJECT AND DESIGN: The therapeutic effect of glucosamine hydrochloride (GH) and chondroitin sulfate (CS) in combination with fursultiamine, a vitamin B1 derivative, on the development of cartilage lesions was investigated in an animal model of osteoarthritis (OA). METHODS: The OA model was created by partial medial meniscectomy of the right knee joint (day 0). The rabbits were placed into three experimental groups: operated (OA) rabbits that received placebo treatment, OA rabbits that received GH (1000 mg/kg) + CS (800 mg/kg), and OA rabbits that received GH + CS + fursultiamine (100 mg/kg). Each treatment was initiated on day 3 and continued for 8 weeks. Macroscopic and histologic analyses were performed on the cartilage. The level of MMP-1 in OA cartilage chondrocytes was evaluated by immunohistochemistry. RESULTS: Only the group receiving combined treatment with GH + CS + fursultiamine showed a significant reduction in the severity of macroscopic and histologic lesions on tibial plateau, which is the weight bearing cartilage surface of the tibia, compared with placebo-treated OA rabbits. This treatment group also revealed a small, but significant, decrease in the body weight gain of the rabbits. In cartilage from placebo-treated OA rabbits, a significantly higher percentage of chondrocytes in superficial layer stained positive for MMP-1 compared with unoperated control. Rabbits treated with the GH + CS + fursultiamine revealed a significant reduction in the level of MMP-1. CONCLUSION: These results suggest that the chondroprotective effect of GH + CS is enhanced by the addition of fursultiamine in experimental OA. This effect was associated with a reduction in the level of MMP-1, which are known to play an important role in the pathophysiology of OA lesions.

Animals↗
PubMed2003

Regulation of two homodimer hexosaminidases in the mycoparasitic fungus Trichoderma asperellum by glucosamine.

Trichoderma asperellum is a mycoparasitic fungus which is used as a biocontrol agent against plant pathogens. Its hydrolytic enzymes take part in its parasitic interaction, degrading the pathogen cell wall and thereby helping to control disease. One of those enzymes, beta- N-acetyl- d-glucosaminidase (GlcNAcase), degrades chitin, which is a major component of the cell wall of many plant-pathogenic fungi. Two GlcNAcases of T. asperellum T203, designated EXC1Y and EXC2Y, were purified, their genes and their promoters were sequenced, and their regulation was studied. The enzymes share homology (59% identity) but are easily distinguished by PAGE assay. Biochemical characterization, Edman degradation, and mass spectrometry demonstrated that EXC1Y and EXC2Y are both active as homodimers. Both genes are up-regulated by glucosamine (GlcN), in contrast to two endochitinases of this fungus. GlcN induces the secretion of several proteins (including a beta-glucosidase), among which EXC1Y is the most abundant. An exc2y knockout was constructed, to study the regulation of EXC1Y expression and secretion. The fungus has the ability to store a high amount of this enzyme in an active form and secrete it into the medium later.

Dimerization↗
PubMed2006

Glucosamine sulfate-induced apoptosis in chronic myelogenous leukemia K562 cells is associated with translocation of cathepsin D and downregulation of Bcl-xL.

Cathepsin D (cat D) reportedly plays an important role in certain apoptotic processes, the downstream pathways of which involve release of cytochrome c (cyt c) from mitochondria and activation of the caspase cascade. Previous studies revealed that the B-cell lymphoma 2 (Bcl-2) family members Bax or Bid play important roles in apoptotic signal transduction between cat D and mitochondria. Here, we show that glucosamine sulfate (GS) inhibits the proliferation and induces apoptosis of human chronic myelogenous leukemia K562 cells in vitro. GS interfered with the maturation of cat D. Activation of caspase-3, cleavage of poly-(ADP-ribose)-polymerase, release of cyt c, and downregulation of Bcl-xL accompanied GS-induced apoptosis, and these processes were inhibited by the cat D inhibitor pepstatin A. However, we did not detect any altered gene expression of Bcl-2, Bax, or Bid during apoptosis. Translocation of cat D from the lysosome to the cytosol was observed in GS-treated K562 cells. These findings suggest that GS-induced K562 cell apoptosis involves the translocation of cat D from the lysosome to the cytosol. Furthermore, our findings suggest that downregulation of Bcl-xL (but not Bcl-2, Bax, or Bid) connects cat D and the mitochondrial pathway, which causes the release of cyt c and activation of the caspase cascade during GS-induced apoptosis of K562 cells.

Apoptosis↗
PubMed1984

Radiometric assays of N-acetylglucosaminylphosphotransferase and alpha-N-acetylglucosaminyl phosphodiesterase with substrates labeled in the glucosamine moiety.

The assay of fibroblast and leukocyte-N-acetylglucosaminylphosphotransferase with alpha-methylmannoside acceptor and commercially available UDP-[3H or 14C]N-acetylglucosamine donor was modified to yield low background and consequently high sensitivity and reliability comparable to those obtained with the synthetically made [beta-32P]UDP-N-acetylglucosamine donor. This was achieved by an additional elution step that removed free [3H or 14C]N-acetylglucosamine which appeared to be the breakdown product responsible for the high background. In addition, the [3H or 14C]N-acetylglucosamine-1-phospho-6-alpha-methylmannoside product of the transfer reaction was then isolated and, following desalting, could serve as a substrate for the assay of alpha-N-acetylglucosaminyl phosphodiesterase. Cell preparations of patients with I-cell disease and pseudo-Hurler polydystrophy demonstrated severe to moderate deficiency of transferase activity and normal phosphodiesterase activity toward the respective substrates labeled with 3H or 14C in the glucosamine moiety.

Binding Sites↗
PubMed1992

Relationship between insulin-mediated turnover of glucosamine-labeled lipids and activity of the insulin receptor tyrosine kinase.

We studied the effects of insulin on the turnover of glucosamine-labeled lipids in embryonic RAT fibroblasts that overexpressed either normal human insulin receptors or insulin receptors with defective tyrosine kinase domains. Fractionation of organic extracts by thin layer chromatography in chloroform/acetone/methanol/acetic acid/water (50/20/10/10/5, v/v) revealed two insulin-sensitive glucosaminyl lipid fractions, the TLC origin (the Rf 0.0 fraction) and a fraction that migrated with Rf 0.18-0.2 (the Rf 0.2 fraction). The insulin-sensitive molecules in both fractions could also be labeled with D-[6-3H]galactose, but not with myo-[2-3H]inositol. Methanolysis and exposure to methylamine, phospholipase A2, or phosphatidylinositol-specific PLC destroyed the insulin-sensitive lipids in the Rf 0.0 fraction, but had no effect on the Rf 0.2 fraction lipid. The Rf 0.2 fraction lipid was destroyed by endoglycoceraminidase. Insulin caused a rapid loss of label from the Rf 0.0 fraction and an equally rapid increased labeling of the Rf 0.2 fraction, with similar time courses and dependencies on insulin concentration. The turnover of both lipids exhibited the same the insulin dose-response characteristics in cultures which overexpressed insulin receptors with defective tyrosine kinase domains as in cultures that overexpressed normal human insulin receptors. This result supports the conclusions that a number of signaling pathways diverge from the insulin receptor and that not all of those pathways are regulated by the insulin receptor tyrosine kinase.

Animals↗
PubMed1987

A synthesis of N-acetylneuraminic acid and [6-2H]-N-acetylneuraminic acid from N-acetyl-D-glucosamine.

N-Acetylneuraminic acid (Neu5Ac) and [6-2H]-Neu5Ac were prepared from 2-acetamido-2-deoxy-D-glucose (N-acetyl-D-glucosamine). Then Henry reaction of a 1-deoxy-1-nitro derivative of GlcNAc (protected 1-C-nitroanhydro-D-glucitol) with cyclohexylidene-D-glyceraldehyde, followed by successive acetylation and reductive denitration with Bu3SnH, gave an anhydrononitol intermediate (6) diastereo-selectively in high yields. Debenzylidenation of 6 freed its distal primary carbinol group, which was subjected to catalytic oxidation followed by hydrolysis, esterification (diazomethane), and acetylation to give a protected methyl nononate. This ester was transformed into the known methyl N-acetyl-4,7,8,9-tetra-O-acetyl-2,3-dehydroneuraminate (15), which was identical with a sample prepared from Neu5Ac. Neu5Ac was obtained from 15 by bromoetherification (NBS, methanol) followed by reductive debromination with Bu3SnH and hydrolysis. Similarly, the [6-2H]-derivative of 15 was transformed into [6-2H]-Neu5Ac.

Acetylglucosamine↗
PubMed1987

Synthesis of the optically active 4-O-phosphono-D-glucosamine derivatives related to the nonreducing-sugar subunit of bacterial lipid A.

The optically active lipid A-subunit homologs named GLA-46, GLA-47, GLA-59, and GLA-60 have been synthesized stepwise by successive acylation at N-2 and O-3 of benzyl 2-amino-2-deoxy-4,6-O-isopropylidene-beta-D-glucopyranoside with the 3-9O-(benzyloxy)methyl or 39O-tetradecanoyl derivative of optically active 3-hydroxytetradecanoic acid, and phosphorylation at O-4 of the D-glucosamine residue.

Glucosamine↗
PubMed1988

Endotoxin-induced tumor necrosis factor (TNF): selective triggering of TNF and interleukin-1 production by distinct glucosamine-derived lipids.

The isolated lipid A of Bordetella pertussis endotoxin (LipA) has been found to induce in vitro release of tumor necrosis factor (TNF) by murine macrophages, albeit much less efficiently than does the intact lipopolysaccharide. Synthetic analogs (monosaccharides M4 and M6) of both glucosamine units present in the LipA backbone induced production of TNF by peritoneal macrophages of Swiss mice. Macrophages from A/J mice gave higher responses than those from Swiss mice, while those of C3H/HeJ mice were unresponsive. Enhancement of TNF secretion was observed for all cells if they were pretreated with a calcium ionophore, and no otherwise inactive substance became active with cells thus treated. For synthetic monosaccharide derivatives, a phosphate group on O-4 was not required for, and a phosphate group on O-1 abolished, the TNF-inducing activity. Synthetic monosaccharides, chemically closely related to substructures recognized to be present in isolated lipid A preparations, could induce either TNF or interleukin-1 (IL-1) production, but not both simultaneously: the monosaccharides M4 and M6 were active TNF inducers, but did not initiate IL-1 production, while the monosaccharides M9 and lipid X efficiently elicited IL-1 production, but did not trigger TNF secretion. It should be noted, however, that the active synthetic compounds are considerably less efficient TNF inducers as is the intact B. pertussis endotoxin.

Animals↗
PubMed1991

Correlations between hyaluronan and epidermal proliferation as studied by [3H]glucosamine and [3H]thymidine incorporations and staining of hyaluronan on mitotic keratinocytes.

The rates of keratinocyte proliferation and synthesis of Hyaluronan (HA) were studied in human whole-skin organ culture by labeling with [6-3H]glucosamine and [3H]thymidine, respectively, to reveal possible correlations between the two functions of the cell. HA distribution in epidermis was examined by staining with a specific probe prepared from cartilage proteoglycan. The keratinocyte proliferation rate was low on the first 2 culture days, but showed a tenfold increase on the third and fourth days while the synthesis of HA proceeded at a relatively stable level throughout the same period. The most intensive staining of HA occurred in the uppermost spinous cell layer, whereas mitotic cells resided in the basal and suprabasal layers. The keratinocytes under various stages of mitosis were surrounded by a HA staining not more intense than that around nondividing basal cells, but a thick pad of HA appeared rapidly between the daughter cells. These findings suggest that newly synthesized HA is associated with the separation of keratinocytes following mitosis but the majority of the synthesis and content of HA in epidermis is involved in other keratinocyte activities such as maintenance of the extracellular space and cell--cell interactions during migration and differentiation.

Adult↗