Mannose: A hexose or fermentable monosaccharide and isomer of glucose from manna, the ash Fraxinus ornus and related plants. (From Grant & Hackh's Chemical Dictionary, 5th ed & Random House Unabridged Dictionary, 2d ed)Mannose-Binding Lectins: A subclass of lectins that are specific for CARBOHYDRATES that contain MANNOSE.Receptor, IGF Type 2: A receptor that is specific for IGF-II and mannose-6-phosphate. The receptor is a 250-kDa single chain polypeptide which is unrelated in structure to the type 1 IGF receptor (RECEPTOR, IGF TYPE 1) and does not have a tyrosine kinase domain.Mannosephosphates: Phosphoric acid esters of mannose.Guanosine Diphosphate Mannose: A nucleoside diphosphate sugar which can be converted to the deoxy sugar GDPfucose, which provides fucose for lipopolysaccharides of bacterial cell walls. Also acts as mannose donor for glycolipid synthesis.Dolichol Monophosphate Mannose: A lipophilic glycosyl carrier of the monosaccharide mannose in the biosynthesis of oligosaccharide phospholipids and glycoproteins.Oligosaccharides: Carbohydrates consisting of between two (DISACCHARIDES) and ten MONOSACCHARIDES connected by either an alpha- or beta-glycosidic link. They are found throughout nature in both the free and bound form.Mannosyltransferases: Enzymes that catalyze the transfer of mannose from a nucleoside diphosphate mannose to an acceptor molecule which is frequently another carbohydrate. The group includes EC 2.4.1.32, EC 2.4.1.48, EC 2.4.1.54, and EC 2.4.1.57.Mannose-6-Phosphate Isomerase: An enzyme that catalyzes the reversible isomerization of D-mannose-6-phosphate to form D-fructose-6-phosphate, an important step in glycolysis. EC 5.3.1.8.Lectins, C-Type: A class of animal lectins that bind to carbohydrate in a calcium-dependent manner. They share a common carbohydrate-binding domain that is structurally distinct from other classes of lectins.Mannans: Polysaccharides consisting of mannose units.Carbohydrates: The largest class of organic compounds, including STARCH; GLYCOGEN; CELLULOSE; POLYSACCHARIDES; and simple MONOSACCHARIDES. Carbohydrates are composed of carbon, hydrogen, and oxygen in a ratio of Cn(H2O)n.HexosephosphatesMannosidases: Glycoside hydrolases that catalyze the hydrolysis of alpha or beta linked MANNOSE.Polyisoprenyl Phosphate Sugars: Compounds functioning as activated glycosyl carriers in the biosynthesis of glycoproteins and glycophospholipids. They include the polyisoprenyl pyrophosphates.Receptors, Cell Surface: Cell surface proteins that bind signalling molecules external to the cell with high affinity and convert this extracellular event into one or more intracellular signals that alter the behavior of the target cell (From Alberts, Molecular Biology of the Cell, 2nd ed, pp693-5). Cell surface receptors, unlike enzymes, do not chemically alter their ligands.Mannosides: Glycosides formed by the reaction of the hydroxyl group on the anomeric carbon atom of mannose with an alcohol to form an acetal. They include both alpha- and beta-mannosides.Carbohydrate Sequence: The sequence of carbohydrates within POLYSACCHARIDES; GLYCOPROTEINS; and GLYCOLIPIDS.Monosaccharides: Simple sugars, carbohydrates which cannot be decomposed by hydrolysis. They are colorless crystalline substances with a sweet taste and have the same general formula CnH2nOn. (From Dorland, 28th ed)PolysaccharidesGlycoproteins: Conjugated protein-carbohydrate compounds including mucins, mucoid, and amyloid glycoproteins.Glycosylation: The chemical or biochemical addition of carbohydrate or glycosyl groups to other chemicals, especially peptides or proteins. Glycosyl transferases are used in this biochemical reaction.alpha-Mannosidase: An enzyme that catalyzes the HYDROLYSIS of terminal, non-reducing alpha-D-mannose residues in alpha-D-mannosides. The enzyme plays a role in the processing of newly formed N-glycans and in degradation of mature GLYCOPROTEINS. There are multiple isoforms of alpha-mannosidase, each having its own specific cellular location and pH optimum. Defects in the lysosomal form of the enzyme results in a buildup of mannoside intermediate metabolites and the disease ALPHA-MANNOSIDOSIS.Polyisoprenyl Phosphate Monosaccharides: These compounds function as activated monosaccharide carriers in the biosynthesis of glycoproteins and oligosaccharide phospholipids. Obtained from a nucleoside diphosphate sugar and a polyisoprenyl phosphate.GlucosamineGalactose: An aldohexose that occurs naturally in the D-form in lactose, cerebrosides, gangliosides, and mucoproteins. Deficiency of galactosyl-1-phosphate uridyltransferase (GALACTOSE-1-PHOSPHATE URIDYL-TRANSFERASE DEFICIENCY DISEASE) causes an error in galactose metabolism called GALACTOSEMIA, resulting in elevations of galactose in the blood.Carbohydrate Conformation: The characteristic 3-dimensional shape of a carbohydrate.Glycopeptides: Proteins which contain carbohydrate groups attached covalently to the polypeptide chain. The protein moiety is the predominant group with the carbohydrate making up only a small percentage of the total weight.Lectins: Proteins that share the common characteristic of binding to carbohydrates. Some ANTIBODIES and carbohydrate-metabolizing proteins (ENZYMES) also bind to carbohydrates, however they are not considered lectins. PLANT LECTINS are carbohydrate-binding proteins that have been primarily identified by their hemagglutinating activity (HEMAGGLUTININS). However, a variety of lectins occur in animal species where they serve diverse array of functions through specific carbohydrate recognition.Lysosomes: A class of morphologically heterogeneous cytoplasmic particles in animal and plant tissues characterized by their content of hydrolytic enzymes and the structure-linked latency of these enzymes. The intracellular functions of lysosomes depend on their lytic potential. The single unit membrane of the lysosome acts as a barrier between the enzymes enclosed in the lysosome and the external substrate. The activity of the enzymes contained in lysosomes is limited or nil unless the vesicle in which they are enclosed is ruptured. Such rupture is supposed to be under metabolic (hormonal) control. (From Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)FucoseDolichol Phosphates: Phosphoric acid esters of dolichol.Methylmannosides: Mannosides formed by the reaction of the hydroxyl group on the anomeric carbon atom of mannose with methyl alcohol. They include both alpha- and beta-methylmannosides.HexosesAcetylglucosamine: The N-acetyl derivative of glucosamine.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Phosphotransferases (Phosphomutases): A group of enzymes that catalyze an intramolecular transfer of a phosphate group. It has been shown in some cases that the enzyme has a functional phosphate group, which can act as the donor. These were previously listed under PHOSPHOTRANSFERASES (EC 2.7.-). (From Enzyme Nomenclature, 1992) EC 5.4.2.Cathepsin D: An intracellular proteinase found in a variety of tissue. It has specificity similar to but narrower than that of pepsin A. The enzyme is involved in catabolism of cartilage and connective tissue. EC 3.4.23.5. (Formerly EC 3.4.4.23).Carbohydrate Metabolism: Cellular processes in biosynthesis (anabolism) and degradation (catabolism) of CARBOHYDRATES.Mannose-Binding Lectin: A specific mannose-binding member of the collectin family of lectins. It binds to carbohydrate groups on invading pathogens and plays a key role in the MANNOSE-BINDING LECTIN COMPLEMENT PATHWAY.Polyisoprenyl Phosphate Oligosaccharides: These compounds function as activated glycosyl carriers in the biosynthesis of glycoproteins and glycophospholipids. Include the pyrophosphates.Hexosaminidases: Enzymes that catalyze the hydrolysis of N-acylhexosamine residues in N-acylhexosamides. Hexosaminidases also act on GLUCOSIDES; GALACTOSIDES; and several OLIGOSACCHARIDES.Glycoside Hydrolasesbeta-Mannosidase: An enzyme that catalyzes the hydrolysis of terminal, non-reducing beta-D-mannose residues in beta-D-mannosides. The enzyme plays a role in the lysosomal degradation of the N-glycosylprotein glycans. Defects in the lysosomal form of the enzyme in humans result in a buildup of mannoside intermediate metabolites and the disease BETA-MANNOSIDOSIS.Swainsonine: An indolizidine alkaloid from the plant Swainsona canescens that is a potent alpha-mannosidase inhibitor. Swainsonine also exhibits antimetastatic, antiproliferative, and immunomodulatory activity.Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase: A group of related enzymes responsible for the endohydrolysis of the di-N-acetylchitobiosyl unit in high-mannose-content glycopeptides and GLYCOPROTEINS.Endocytosis: Cellular uptake of extracellular materials within membrane-limited vacuoles or microvesicles. ENDOSOMES play a central role in endocytosis.GlucuronidaseNucleoside Diphosphate SugarsPlant Lectins: Protein or glycoprotein substances of plant origin that bind to sugar moieties in cell walls or membranes. Some carbohydrate-metabolizing proteins (ENZYMES) from PLANTS also bind to carbohydrates, however they are not considered lectins. Many plant lectins change the physiology of the membrane of BLOOD CELLS to cause agglutination, mitosis, or other biochemical changes. They may play a role in plant defense mechanisms.Glycolipids: Any compound containing one or more monosaccharide residues bound by a glycosidic linkage to a hydrophobic moiety such as an acylglycerol (see GLYCERIDES), a sphingoid, a ceramide (CERAMIDES) (N-acylsphingoid) or a prenyl phosphate. (From IUPAC's webpage)Dolichol: Eicosamethyl octacontanonadecasen-1-o1. Polyprenol found in animal tissues that contains about 20 isoprene residues, the one carrying the alcohol group being saturated.Kinetics: The rate dynamics in chemical or physical systems.Phosphoenolpyruvate Sugar Phosphotransferase System: The bacterial sugar phosphotransferase system (PTS) that catalyzes the transfer of the phosphoryl group from phosphoenolpyruvate to its sugar substrates (the PTS sugars) concomitant with the translocation of these sugars across the bacterial membrane. The phosphorylation of a given sugar requires four proteins, two general proteins, Enzyme I and HPr and a pair of sugar-specific proteins designated as the Enzyme II complex. The PTS has also been implicated in the induction of synthesis of some catabolic enzyme systems required for the utilization of sugars that are not substrates of the PTS as well as the regulation of the activity of ADENYLYL CYCLASES. EC 2.7.1.-.Golgi Apparatus: A stack of flattened vesicles that functions in posttranslational processing and sorting of proteins, receiving them from the rough ENDOPLASMIC RETICULUM and directing them to secretory vesicles, LYSOSOMES, or the CELL MEMBRANE. The movement of proteins takes place by transfer vesicles that bud off from the rough endoplasmic reticulum or Golgi apparatus and fuse with the Golgi, lysosomes or cell membrane. (From Glick, Glossary of Biochemistry and Molecular Biology, 1990)Collectins: A class of C-type lectins that target the carbohydrate structures found on invading pathogens. Binding of collectins to microorganisms results in their agglutination and enhanced clearance. Collectins form trimers that may assemble into larger oligomers. Each collectin polypeptide chain consists of four regions: a relatively short N-terminal region, a collagen-like region, an alpha-helical coiled-coil region, and carbohydrate-binding region.Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Tunicamycin: An N-acetylglycosamine containing antiviral antibiotic obtained from Streptomyces lysosuperificus. It is also active against some bacteria and fungi, because it inhibits the glucosylation of proteins. Tunicamycin is used as tool in the study of microbial biosynthetic mechanisms.Congenital Disorders of Glycosylation: A genetically heterogeneous group of heritable disorders resulting from defects in protein N-glycosylation.Molecular Weight: The sum of the weight of all the atoms in a molecule.Imino Furanoses: Five-carbon furanose sugars in which the OXYGEN is replaced by a NITROGEN atom.1-Deoxynojirimycin: An alpha-glucosidase inhibitor with antiviral action. Derivatives of deoxynojirimycin may have anti-HIV activity.Glucose: A primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement.Chromatography, Paper: An analytical technique for resolution of a chemical mixture into its component compounds. Compounds are separated on an adsorbent paper (stationary phase) by their varied degree of solubility/mobility in the eluting solvent (mobile phase).Mucolipidoses: A group of inherited metabolic diseases characterized by the accumulation of excessive amounts of acid mucopolysaccharides, sphingolipids, and/or glycolipids in visceral and mesenchymal cells. Abnormal amounts of sphingolipids or glycolipids are present in neural tissue. INTELLECTUAL DISABILITY and skeletal changes, most notably dysostosis multiplex, occur frequently. (From Joynt, Clinical Neurology, 1992, Ch56, pp36-7)Chromatography, Affinity: A chromatographic technique that utilizes the ability of biological molecules to bind to certain ligands specifically and reversibly. It is used in protein biochemistry. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Cell Line: Established cell cultures that have the potential to propagate indefinitely.IndolizinesInsulin-Like Growth Factor II: A well-characterized neutral peptide believed to be secreted by the LIVER and to circulate in the BLOOD. It has growth-regulating, insulin-like and mitogenic activities. The growth factor has a major, but not absolute, dependence on SOMATOTROPIN. It is believed to be a major fetal growth factor in contrast to INSULIN-LIKE GROWTH FACTOR I, which is a major growth factor in adults.Macrophages: The relatively long-lived phagocytic cell of mammalian tissues that are derived from blood MONOCYTES. Main types are PERITONEAL MACROPHAGES; ALVEOLAR MACROPHAGES; HISTIOCYTES; KUPFFER CELLS of the liver; and OSTEOCLASTS. They may further differentiate within chronic inflammatory lesions to EPITHELIOID CELLS or may fuse to form FOREIGN BODY GIANT CELLS or LANGHANS GIANT CELLS. (from The Dictionary of Cell Biology, Lackie and Dow, 3rd ed.)Chromatography, Gel: Chromatography on non-ionic gels without regard to the mechanism of solute discrimination.Asparagine: A non-essential amino acid that is involved in the metabolic control of cell functions in nerve and brain tissue. It is biosynthesized from ASPARTIC ACID and AMMONIA by asparagine synthetase. (From Concise Encyclopedia Biochemistry and Molecular Biology, 3rd ed)Glycosylphosphatidylinositols: Compounds containing carbohydrate or glycosyl groups linked to phosphatidylinositols. They anchor GPI-LINKED PROTEINS or polysaccharides to cell membranes.Acetylglucosaminidase: A beta-N-Acetylhexosaminidase that catalyzes the hydrolysis of terminal, non-reducing 2-acetamido-2-deoxy-beta-glucose residues in chitobiose and higher analogs as well as in glycoproteins. Has been used widely in structural studies on bacterial cell walls and in the study of diseases such as MUCOLIPIDOSIS and various inflammatory disorders of muscle and connective tissue.Electrophoresis, Polyacrylamide Gel: Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.Biological Transport: The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.HexosaminesCricetinae: A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.Carbohydrate Metabolism, Inborn ErrorsPeptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase: An amidohydrolase that removes intact asparagine-linked oligosaccharide chains from glycoproteins. It requires the presence of more than two amino-acid residues in the substrate for activity. This enzyme was previously listed as EC 3.2.2.18.beta-N-Acetylhexosaminidases: A hexosaminidase specific for non-reducing N-acetyl-D-hexosamine residues in N-acetyl-beta-D-hexosaminides. It acts on GLUCOSIDES; GALACTOSIDES; and several OLIGOSACCHARIDES. Two specific mammalian isoenzymes of beta-N-acetylhexoaminidase are referred to as HEXOSAMINIDASE A and HEXOSAMINIDASE B. Deficiency of the type A isoenzyme causes TAY-SACHS DISEASE, while deficiency of both A and B isozymes causes SANDHOFF DISEASE. The enzyme has also been used as a tumor marker to distinguish between malignant and benign disease.Acetylgalactosamine: The N-acetyl derivative of galactosamine.alpha-Glucosidases: Enzymes that catalyze the exohydrolysis of 1,4-alpha-glucosidic linkages with release of alpha-glucose. Deficiency of alpha-1,4-glucosidase may cause GLYCOGEN STORAGE DISEASE TYPE II.Endosomes: Cytoplasmic vesicles formed when COATED VESICLES shed their CLATHRIN coat. Endosomes internalize macromolecules bound by receptors on the cell surface.Chromatography, Thin Layer: Chromatography on thin layers of adsorbents rather than in columns. The adsorbent can be alumina, silica gel, silicates, charcoals, or cellulose. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Protein Processing, Post-Translational: Any of various enzymatically catalyzed post-translational modifications of PEPTIDES or PROTEINS in the cell of origin. These modifications include carboxylation; HYDROXYLATION; ACETYLATION; PHOSPHORYLATION; METHYLATION; GLYCOSYLATION; ubiquitination; oxidation; proteolysis; and crosslinking and result in changes in molecular weight and electrophoretic motility.Cell Membrane: The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.Fructose: A monosaccharide in sweet fruits and honey that is soluble in water, alcohol, or ether. It is used as a preservative and an intravenous infusion in parenteral feeding.Flocculation: The aggregation of suspended solids into larger clumps.Transferases (Other Substituted Phosphate Groups): A class of enzymes that transfers substituted phosphate groups. EC 2.7.8.Galanthus: A plant genus in the family LILIACEAE (sometimes classified as Amaryllidaceae). Galanthus nivalis L. is the source of GALANTHAMINE.Amino Acids: Organic compounds that generally contain an amino (-NH2) and a carboxyl (-COOH) group. Twenty alpha-amino acids are the subunits which are polymerized to form proteins.Fructokinases: A class of enzymes that catalyzes the phosphorylation of fructose in the presence of ATP. EC 2.7.1.-.Liver: A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.Carrier Proteins: Transport proteins that carry specific substances in the blood or across cell membranes.Cell Wall: The outermost layer of a cell in most PLANTS; BACTERIA; FUNGI; and ALGAE. The cell wall is usually a rigid structure that lies external to the CELL MEMBRANE, and provides a protective barrier against physical or chemical agents.trans-Golgi Network: A network of membrane compartments, located at the cytoplasmic side of the GOLGI APPARATUS, where proteins and lipids are sorted for transport to various locations in the cell or cell membrane.Cells, Cultured: Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.Ligands: A molecule that binds to another molecule, used especially to refer to a small molecule that binds specifically to a larger molecule, e.g., an antigen binding to an antibody, a hormone or neurotransmitter binding to a receptor, or a substrate or allosteric effector binding to an enzyme. Ligands are also molecules that donate or accept a pair of electrons to form a coordinate covalent bond with the central metal atom of a coordination complex. (From Dorland, 27th ed)Guanosine Diphosphate Sugars: Esters formed between the aldehydic carbon of sugars and the terminal phosphate of guanosine diphosphate.Protein Binding: The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.Membrane Glycoproteins: Glycoproteins found on the membrane or surface of cells.Uridine Diphosphate N-Acetylglucosamine: Serves as the biological precursor of insect chitin, of muramic acid in bacterial cell walls, and of sialic acids in mammalian glycoproteins.Rhamnose: A methylpentose whose L- isomer is found naturally in many plant glycosides and some gram-negative bacterial lipopolysaccharides.Endoplasmic Reticulum: A system of cisternae in the CYTOPLASM of many cells. In places the endoplasmic reticulum is continuous with the plasma membrane (CELL MEMBRANE) or outer membrane of the nuclear envelope. If the outer surfaces of the endoplasmic reticulum membranes are coated with ribosomes, the endoplasmic reticulum is said to be rough-surfaced (ENDOPLASMIC RETICULUM, ROUGH); otherwise it is said to be smooth-surfaced (ENDOPLASMIC RETICULUM, SMOOTH). (King & Stansfield, A Dictionary of Genetics, 4th ed)Mutation: Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.Cations: Positively charged atoms, radicals or groups of atoms which travel to the cathode or negative pole during electrolysis.Recombinant Proteins: Proteins prepared by recombinant DNA technology.XyloseConcanavalin A: A MANNOSE/GLUCOSE binding lectin isolated from the jack bean (Canavalia ensiformis). It is a potent mitogen used to stimulate cell proliferation in lymphocytes, primarily T-lymphocyte, cultures.Sugar Alcohols: Polyhydric alcohols having no more than one hydroxy group attached to each carbon atom. They are formed by the reduction of the carbonyl group of a sugar to a hydroxyl group.(From Dorland, 28th ed)Deoxy SugarsFibroblasts: Connective tissue cells which secrete an extracellular matrix rich in collagen and other macromolecules.Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.Substrate Specificity: A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.Cattle: Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.Polyisoprenyl Phosphates: Phosphoric or pyrophosphoric acid esters of polyisoprenoids.Magnetic Resonance Spectroscopy: Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING).Receptors, Mitogen: Glycoprotein molecules on the surface of B- and T-lymphocytes, that react with molecules of antilymphocyte sera, lectins, and other agents which induce blast transformation of lymphocytes.Receptors, Immunologic: Cell surface molecules on cells of the immune system that specifically bind surface molecules or messenger molecules and trigger changes in the behavior of cells. Although these receptors were first identified in the immune system, many have important functions elsewhere.Chromatography, Ion Exchange: Separation technique in which the stationary phase consists of ion exchange resins. The resins contain loosely held small ions that easily exchange places with other small ions of like charge present in solutions washed over the resins.Pinocytosis: The engulfing of liquids by cells by a process of invagination and closure of the cell membrane to form fluid-filled vacuoles.Glycoconjugates: Carbohydrates covalently linked to a nonsugar moiety (lipids or proteins). The major glycoconjugates are glycoproteins, glycopeptides, peptidoglycans, glycolipids, and lipopolysaccharides. (From Biochemical Nomenclature and Related Documents, 2d ed; From Principles of Biochemistry, 2d ed)

Participation of a trisaccharide-lipid in glycosylation of oviduct membrane glycoproteins. (1/2363)

Preincubation of a hen oviduct membrane preparation with UDP-Nactyl[14C]glucosamine and bacitracin, followed by incubation with GDP-mannose, leads to formation of a chloroform/methanol (2/1)-extractable glycolipid. Treatment of the lipid with mild acid results in the release of a trisaccharide shown to have the structure beta-mannosyl-N-acetylglucosamineyl-N-acetylglucosamine. Incubation of purified trisaccharide-lipid with oviduct membranes in the presence of sodium deoxycholate, Mn2+, and GDP-mannose leads to formation of a labeled glycoprotein with an apparent molecular weight of 25,000...  (+info)

Mannose inhibits Arabidopsis germination via a hexokinase-mediated step. (2/2363)

Low concentrations of the glucose (Glc) analog mannose (Man) inhibit germination of Arabidopsis seeds. Man is phosphorylated by hexokinase (HXK), but the absence of germination was not due to ATP or phosphate depletion. The addition of metabolizable sugars reversed the Man-mediated inhibition of germination. Carbohydrate-mediated regulation of gene expression involving a HXK-mediated pathway is known to be activated by Glc, Man, and other monosaccharides. Therefore, we investigated whether Man blocks germination through this system. By testing other Glc analogs, we found that 2-deoxyglucose, which, like Man, is phosphorylated by HXK, also blocked germination; no inhibition was observed with 6-deoxyglucose or 3-O-methylglucose, which are not substrates for HXK. Since these latter two sugars are taken up at a rate similar to that of Man, uptake is unlikely to be involved in the inhibition of germination. Furthermore, we show that mannoheptulose, a specific HXK inhibitor, restores germination of seeds grown in the presence of Man. We conclude that HXK is involved in the Man-mediated repression of germination of Arabidopsis seeds, possibly via energy depletion.  (+info)

Glycosylation of asparagine-28 of recombinant staphylokinase with high-mannose-type oligosaccharides results in a protein with highly attenuated plasminogen activator activity. (3/2363)

The properties of recombinant staphylokinase (SakSTAR) expressed in Pichia pastoris cells have been determined. The single consensus N-linked oligosaccharide linkage site in SakSTAR (at Asn28 of the mature protein) was occupied in approximately 50% of the expressed protein with high-mannose-type oligosaccharides. The majority of these glycans ranged in polymerization state from Man8GlcNAc2 to Man14GlcNAc2, with the predominant species being Man10GlcNAc2 and Man11GlcNAc2. Glycosylated SakSTAR (SakSTARg) did not differ from its aglycosyl form in its aggregation state in solution, its thermal denaturation properties, its ability to form a complex with human plasmin (hPm), the amidolytic properties of the respective SakSTAR-hPm complexes, or its ability to liberate the amino-terminal decapeptide required for formation of a functional SakSTAR-hPm plasminogen activator complex. However, this latter complex with SakSTARg showed a greatly reduced ability to activate human plasminogen (hPg) as compared with the same complex with the aglycosyl form of SakSTAR. We conclude that glycosylation at Asn28 does not affect the structural properties of SakSTAR or its ability to participate in the formation of an active enzymatic complex with hPm, but it is detrimental to the ability of the SakSTAR-hPm complex to serve as a hPg activator. This is likely due to restricted access of hPg to the active site of the SakSTARg-hPm complex.  (+info)

Genetic evidence for the role of GDP-mannose in plant ascorbic acid (vitamin C) biosynthesis. (4/2363)

Vitamin C (L-ascorbic acid; AsA) acts as a potent antioxidant and cellular reductant in plants and animals. AsA has long been known to have many critical physiological roles in plants, yet its biosynthesis is only currently being defined. A pathway for AsA biosynthesis that features GDP-mannose and L-galactose has recently been proposed for plants. We have isolated a collection of AsA-deficient mutants of Arabidopsis thaliana that are valuable tools for testing of an AsA biosynthetic pathway. The best-characterized of these mutants (vtc1) contains approximately 25% of wild-type AsA and is defective in AsA biosynthesis. By using a combination of biochemical, molecular, and genetic techniques, we have demonstrated that the VTC1 locus encodes a GDP-mannose pyrophosphorylase (mannose-1-P guanyltransferase). This enzyme provides GDP-mannose, which is used for cell wall carbohydrate biosynthesis and protein glycosylation as well as for AsA biosynthesis. In addition to genetically defining the first locus involved in AsA biosynthesis, this work highlights the power of using traditional mutagenesis techniques coupled with the Arabidopsis Genome Initiative to rapidly clone physiologically important genes.  (+info)

Alteration of mannose transport in fibroblasts from type I carbohydrate deficient glycoprotein syndrome patients. (5/2363)

The aim of the present study was to explore how mannose enters fibroblasts derived from a panel of children suffering from different subtypes of type I carbohydrate deficient glycoprotein syndrome: seven carbohydrate deficient glycoprotein syndrome subtype Ia (phosphomannomutase deficiency), two carbohydrate deficient glycoprotein syndrome subtype Ib (phosphomannose isomerase deficiency) and two carbohydrate deficient glycoprotein syndrome subtype Ix (not identified deficiency). We showed that a specific mannose transport system exists in all the cells tested but has different characteristics with respect to carbohydrate deficient glycoprotein syndrome subtypes. Subtype Ia fibroblasts presented a mannose uptake equivalent or higher (maximum 1.6-fold) than control cells with a D-[2-3H]-mannose incorporation in nascent N-glycoproteins decreased up to 7-fold. Compared to control cells, the mannose uptake was greatly stimulated in subtype Ib (4.0-fold), due to lower Kuptake and higher Vmax values. Subtype Ib cells showed an increased incorporation of D-[2-3H]-mannose into nascent N-glycoproteins. Subtype Ix fibroblasts presented an intermediary status with mannose uptake equivalent to the control but with an increased incorporation of D-[2-3H]-mannose in nascent N-glycoproteins. All together, our results demonstrate quantitative and/or qualitative modifications in mannose transport of all carbohydrate deficient glycoprotein syndrome fibroblasts in comparison to control cells, with a relative homogeneity within a considered subtype of carbohydrate deficient glycoprotein syndrome. These results are consistent with the possible use of mannose as a therapeutic agent in carbohydrate deficient glycoprotein syndrome Ib and Ix.  (+info)

Sugars and sugar derivatives which inhibit the short-circuit current of the everted small intestine of the rat. (6/2363)

1. The short-circuit current of everted rat intestine supported on a perforated cannula proved to be stable for up to 3 hr and has been used to study competition between transportable and non-transportable sugars. 2. 4,6-O-Ethylidene-alpha-D-glucopyranose (ethylidene glucose) and 4,6-O-benzylidene-e alpha-D-glucopyranos (benzylinene glucose), two nontransportable inhibitors of the hexose transfer system in human erythrocytes, were found to reduce the short-circuit current generated by transportable sugars such as galactose or 3-O-methyl glucose. 3. These compounds were also found to reduce the basal short-circuit current established by the everted intestine in a sugar-free Krebs solution. Both types of inhibition approached saturation at the higher concentrations used. 4. Similar inhibitory properties were shown by mannose, a non-actively accumulated monosaccharide, and by the beta-disaccharides lactose and cellobiose. 5. It is suggested that this common pattern of behaviour is due to the ability of these compounds to react with the sites for active hexose transfer but without translocation by the system. The significance of the inhibition of the basal short-circuit current is briefly discussed in this context.  (+info)

Transmembrane folding of the human erythrocyte anion exchanger (AE1, Band 3) determined by scanning and insertional N-glycosylation mutagenesis. (7/2363)

The human erythrocyte anion exchanger (AE1, Band 3) contains up to 14 transmembrane segments, with a single site of N-glycosylation at Asn642 in extracellular (EC) loop 4. Scanning and insertional N-glycosylation mutagenesis were used to determine the folding pattern of AE1 in the membrane. Full-length AE1, when expressed in transfected human embryonic kidney (HEK)-293 or COS-7 cells, retained a high-mannose oligosaccharide structure. Scanning N-glycosylation mutagenesis of EC loop 4 showed that N-glycosylation acceptor sites (Asn-Xaa-Ser/Thr) spaced 12 residues from the ends of adjacent transmembrane segments could be N-glycosylated. An acceptor site introduced at position 743 in intracellular (IC) loop 5 that could be N-glycosylated in a cell-free translation system was not N-glycosylated in transfected cells. Mutations designed to disrupt the folding of this loop enhanced the level of N-glycosylation at Asn743 in vitro. The results suggest that this loop might be transiently exposed to the lumen of the endoplasmic reticulum during biosynthesis but normally folds rapidly, precluding N-glycosylation. EC loop 4 insertions into positions 428, 484, 754 and 854 in EC loops 1, 2, 6 and 7 respectively were efficiently N-glycosylated, showing that these regions were extracellular. EC loop 4 insertions into positions 731 or 785 were poorly N-glycosylated, which was inconsistent with an extracellular disposition for these regions of AE1. Insertion of EC loop 4 into positions 599 and 820 in IC loops 3 and 6 respectively were not N-glycosylated in cells, which was consistent with a cytosolic disposition for these loops. Inhibitor-affinity chromatography with 4-acetamido-4'-isothiocyanostilbene-2,2'-disulphonate (SITS)-Affi-Gel was used to assess whether the AE1 mutants were in a native state. Mutants with insertions at positions 428, 484, 599, 731 and 785 showed impaired inhibitor binding, whereas insertions at positions 754, 820 and 854 retained binding. The results indicate that the folding of the C-terminal region of AE1 is more complex than originally proposed and that this region of the transporter might have a dynamic aspect.  (+info)

Recombinant human interleukin-12 is the second example of a C-mannosylated protein. (8/2363)

The beta-chain of human interleukin 12 (IL-12) contains at position 319-322, the sequence Trp-x-x-Trp. In human RNase 2 this is the recognition motif for a new, recently discovered posttranslational modification, i.e., the C-glycosidic attachment of a mannosyl residue to the side chain of tryptophan. Analysis of C-terminal peptides of recombinant IL-12 (rHuIL-12) by mass spectrometry and NMR spectroscopy revealed that Trp-319beta is (partially) C-mannosylated. This finding was extended by in vitro mannosylation experiments, using a synthetic peptide derived from the same region of the protein as an acceptor. Furthermore, human B-lymphoblastoid cells, which secrete IL-12, were found to contain an enzyme that carries out the C-mannosylation reaction. This shows that nonrecombinant IL-12 is potentially C-mannosylated as well. This is only the second report on a C-mannosylated protein. However, the occurrence of the C-mannosyltransferase activity in a variety of cells and tissues, and the presence of the recognition motif in many proteins indicate that more C-mannosylated proteins may be found.  (+info)

  • The acquisition of mannose 6-phosphate (Man6P) on N-linked glycans of lysosomal enzymes is a structural requirement for their transport from the Golgi apparatus to lysosomes mediated by the mannose 6-phosphate receptors, 300 kDa cation-independent mannose 6-phosphate receptor (MPR300) and 46 kDa cation-dependent mannose 6-phosphate receptor (MPR46). (harvard.edu)
  • Single crystal X-ray diffraction analysis to 2.7 Å resolution of Fv M6P-1 in complex with Man6P reveals that specificity and affinity is achieved via multiple hydrogen bonds to the mannose ring and two salt bridges to the phosphate moiety. (harvard.edu)
  • The idea that mannose supplements can help prevent or treat bladder infections derives from a property of the E. coli bacteria. (portsmouthhospital.com)
  • Reasoning from this fact of basic science, medical researchers in the 1980s hypothesized that consumption of mannose as a supplement will increase levels of mannose in the urine to such an extent that this free mannose will saturate the E. coli's mannose-binding pili and thereby make the bacteria unable to grapple onto the cells of the bladder wall. (portsmouthhospital.com)
  • 1 When these pili are saturated by mannose, white blood cells (specifically, macrophages) are less able to consume the E. coli bacteria. (portsmouthhospital.com)
  • 3-4 Third, there are numerous other bacteria that cause bladder infections, and these are not known or suspected to have mannose-sensitive pili. (portsmouthhospital.com)
  • D-Mannose is a monosaccharide hexose sugar that is part of the family of sugars in the aldohexose series. (superiorlabs.com)
  • Even though, human bodies are able to metabolize only a small amount of D-Mannose, much of this is eliminated through urine. (vitadigest.com)
  • Relying on evidence that is both exceedingly preliminary and highly inconsistent, some alternative medicine practitioners have popularized mannose as a treatment for urinary tract infections. (portsmouthhospital.com)
  • D-Mannose is a naturally secreting sugar, which is safe and best alternative to cure UTIs (urinary tract infections). (vitadigest.com)
  • It was found that mannose showed potential anticancer effects against NSCLC cells in vitro by inhibiting proliferation, inducing G0/G1 cell cycle arrest, promoting cisplatin‑induced apoptosis and decreasing the invasive abilities. (omgcb.com)
  • Many, though not all, strains of E. coli have the ability to attach to the mannose present in the wall of the bladder by means of thread-like structures called pili. (portsmouthhospital.com)
  • First, one of the main ways that the body's white blood cells recognize and kill E. coli is via these mannose-sensitive pili. (portsmouthhospital.com)
  • 2 Second, many species of E. coli , including some of the most dangerous, do not have mannose-sensitive pili at all. (portsmouthhospital.com)
  • However, with the presence of D-mannose, Escherichia coli preferably stick on to D-Mannose particles forming a compound that is ejected through excretion. (vitadigest.com)
  • Very weak evidence from test tube studies hints that consumption of gigantic amounts of mannose by pregnant women could conceivably increase risk of birth defects in their offspring. (portsmouthhospital.com)
  • The name Manapol is derived from the mannose polyoses found widely in clean Aloe gel. (vitadigest.com)
  • It appears that your body can produce all the mannose it needs from other sugars in your diet, so you shouldn't need to take any of it. (thenakedscientists.com)
  • Find the foundation of all the essential sugars with Spectrum's large inventory of mannose sugars. (spectrumchemical.com)
  • Spectrum specializes in providing the top mannose sugars but if you do not see the product, grade or form of the ingredient you require, just contact our chemical specialist at 800-772-8786. (spectrumchemical.com)
  • Since D-Mannose is processed differently than other types of sugars‚ it's less likely to cause a rapid sugar rush (and subsequent crash). (pureformulas.com)
  • Because D-Mannose is not metabolized like other sugars, it has a minimal impact on blood sugar regulation. (nutritionexpress.com)
  • D-Mannose is one of the simple sugars naturally found in cranberries and pineapples known for its ability to protect and nourish the urinary tract. (tasmanhealth.co.nz)
  • C-type (Ca(2+)-dependent) animal lectins such as mannose-binding proteins mediate many cell-surface carbohydrate-recognition events. (nih.gov)
  • The crystal structure at 1.7 A resolution of the carbohydrate-recognition domain of rat mannose-binding protein complexed with an oligomannose asparaginyl-oligosaccharide reveals that Ca2+ forms coordination bonds with the carbohydrate ligand. (nih.gov)
  • The delivery of soluble hydrolases to lysosomes is mediated by the cation-independent and cation-dependent mannose 6-phosphate receptors. (sciencemag.org)
  • Thus, the GGAs appear to mediate sorting of the mannose 6-phosphate receptors at the trans-Golgi network. (sciencemag.org)
  • Both mannose 6-phosphate receptors (MPRs) mediate recruitment of the lysosomal hydrolases to clathrin-coated areas of the TGN, from which carrier vesicles deliver the MPR-hydrolase complexes to endosomes. (sciencemag.org)
  • Mannose 6-phosphate receptors (MPRs) transport newly synthesized lysosomal hydrolases from the Golgi to prelysosomes and then return to the Golgi for another round of transport. (nih.gov)
  • In this study, we enhanced the biocontrol abilities of T. atroviride P1 against plant pathogens by overexpressing the Saccharomyces cerevisiae DPM1 gene coding for dolichyl phosphate mannose (DPM) synthase, a key enzyme in the O-glycosylation pathway. (apsnet.org)
  • It is initiated by the en bloc transfer on Glc3Man9GlcNAc2 to nascent glycoproteins in the endoplasmic reticulum in a co-translational manner as the protein entered through the transport system. (wikipedia.org)
  • Functional mannose-binding lectins are made up of two to six protein groups called trimers, which are each composed of three of the protein pieces (subunits) produced from the MBL2 gene. (medlineplus.gov)
  • Mannose-binding protein is also an acute phase reactant produced by the liver. (uiowa.edu)
  • Patients who have abnormal levels of mannose-binding protein may have recurrent significant infections in the absence of abnormalities in the four major arms of the immune system. (uiowa.edu)
  • Abnormal mannose-binding protein concentrations have been found in patients with infectious disorders such as tuberculosis, hepatitis B, and in autoimmune disorders including recurrent spontaneous abortion and systemic lupus erythematosis. (uiowa.edu)
  • Although D-mannose has promising attributes, antibiotics are still the most effective course of treatment to get rid of the infection and prevent it from spreading to the kidneys. (reference.com)
  • My urologist suggested that I try d-mannose after a year of battling E. Coli urinary tract infections treated with antibiotics followed by the UTI returning. (consumerlab.com)
  • Combination of cranberry extract and D-mannose - possible enhancer of uropathogen sensitivity to antibiotics in acute therapy of urinary tract infections. (greenmedinfo.com)
  • D-mannose by Bio-Tech Pharmacal is very effective at treating and preventing bladder infections, d-mannose has worked far better for me then antibiotics and is a completely natural therapy, which is a huge plus! (pureformulas.com)
  • Unlike antibiotics, D-Mannose may actually improve conditions for intestinal flora and probiotics to flourish, creating a healthy environment for digestion and nutrient absorption. (allstarhealth.com)
  • D-Mannose is a natural sugar that has been studied for its potential ability to support a normal, healthy urinary tract. (fredmeyer.com)
  • Clinical studies have demonstrated that when taken regularly, D-Mannose can help to maintain a healthy urinary tract. (picknsave.com)
  • Due to its unique properties and actions in the body, D-mannose can support a healthy urinary tract. (nutritionexpress.com)
  • 1. A fast-dissolving pharmaceutical tablet comprising a dissolution-effective amount of mannose, which tablet has a hardness of at least about 20 newtons and which disintegrates within about 30 seconds in the presence of an amount of water sufficient to soak the tablet. (freepatentsonline.com)
  • 2. The tablet of claim 1, wherein the dissolution-effective amount of mannose ranges from about 1% to about 100% by weight of the tablet. (freepatentsonline.com)
  • First, one of the main ways that the body's white blood cells recognize and kill E. coli is via these mannose-sensitive pili. (portsmouthhospital.com)
  • This syndrome is an inherited metabolic disorder that interferes with the body's ability to properly break down and produce mannose. (pureformulas.com)
  • In the urinary tract, D-mannose complements the body's natural elimination process by maintaining a healthy environment in the bladder. (nowfoods.com)
  • Also: "Human plasma contains ~50μM mannose which is primarily derived from N-glycan processing . (cancercompass.com)
  • Lysosomal hydrolases are posttranslationally modified in the Golgi complex by the addition of mannose 6-phosphate groups that function as signals for sorting to lysosomes ( 1 ). (sciencemag.org)
  • MY mother suffered from recurrent UTIs until she started using D Mannose. (consumerlab.com)
  • The combination of D-mannose, inulin, cranberry, bearberry, Olea europaea, Orthosiphon and Lactobacillus acidophilus SGL 11 per os represents a useful therapy for recurrent UTIs. (greenmedinfo.com)
  • In this pilot study the aim was to evaluate if oral D Mannose could be used as a safe and effective treatment and as a prophylactic measure for recurrent UTIs in adult women. (clinicaltrials.gov)
  • D-mannose can help cure more than 90 percent of all UTIs within 1 to 2 days! (healthimpactnews.com)
  • Before discovering D-Mannose, I would get several UTIs a year and switch to either Bactrim or Levaquin to cure the infection. (allstarhealth.com)
  • I believe the D-Mannose is the reason I have less UTIs. (allstarhealth.com)
  • Biosynthesis of mammalian O-mannosyl glycans is initiated by the transfer of mannose from mannose-P-Dol to serine or threonine residue, followed by extensions with N-acetylglucosamine (GlcNAc) and galactose (Gal) to generate core M1, M2 and M3 glycans. (genome.jp)
  • http://www.functionalglycomics.org/glycomics/search/jsp/result.jsp?query=mannose%20AND%20receptor&cat=coreh here]. (functionalglycomics.org)