Artykuły w czasopismach na temat „Mannose”
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Sampaio, Maria-Manuel, Helena Santos i Winfried Boos. "Synthesis of GDP-Mannose and Mannosylglycerate from Labeled Mannose by Genetically Engineered Escherichia coli without Loss of Specific Isotopic Enrichment". Applied and Environmental Microbiology 69, nr 1 (styczeń 2003): 233–40. http://dx.doi.org/10.1128/aem.69.1.233-240.2003.
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ABSTRACT We report the construction of an Escherichia coli mutant that harbors two compatible plasmids and that is able to synthesize labeled 2-O-α-d-mannosyl-d-glycerate from externally added labeled mannose without the loss of specific isotopic enrichment. The strain carries a deletion in the manA gene, encoding phosphomannose isomerase. This deletion prevents the formation of fructose-6-phosphate from mannose-6-phosphate after the uptake of mannose from the medium by mannose-specific enzyme II of the phosphotransferase system (PtsM). The strain also has a deletion of the cps gene cluster that prevents the synthesis of colanic acid, a mannose-containing polymer. Plasmid-encoded phosphomannomutase (cpsG) and mannose-1-phosphate guanylyltransferase (cpsB) ensure the formation of GDP-mannose. A second plasmid harbors msg, a gene from Rhodothermus marinus that encodes mannosylglycerate synthase, which catalyzes the formation of 2-O-α-d-mannosyl-d-glycerate from GDP-mannose and endogenous glycerate. The rate-limiting step in 2-O-α-d-mannosyl-d-glycerate formation is the transfer of GDP-mannose to glycerate. 2-O-α-d-mannosyl-d-glycerate can be released from cells by treatment with cold-water shock. The final product is formed in a yield exceeding 50% the initial quantity of labeled mannose, including loss during preparation and paper chromatography.
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White, Catherine W., i Eric S. Jacobson. "Mannosyl transfer in Cryptococcus neoformans". Canadian Journal of Microbiology 39, nr 1 (1.01.1993): 129–33. http://dx.doi.org/10.1139/m93-019.
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A particulate enzyme preparation from Cryptococcus neoformans transferred the mannosyl residue from GDP-mannose:o an acceptor consisting of a commercial preparation of methyl 3-O-α-mannopyranosyl-α-mannopyranoside (confining 10% 2-O-α-mannopyranosyl-α-mannopyranoside). The configuration of the new bond was alpha by its susceptibility to α-mannosidase; the amount of product was dependent on the concentration of enzyme, of GDP-mannose, and of acceptor. The optimal temperature and pH were 37 °C and 7.0, respectively. Manganous ion was required for activity and acetyl coenzyme A was stimulatory. Studies suggested that dolichyl phosphate intermediates were not involved in this mannose transfer. The fact that none of the several acapsular mutants tested were deficient in this mannosyltransferase suggested that this enzyme was not involved in synthesis of backbone mannan linkages in capsular polysaccharide. NMR analysis of the methylmannotriose product showed only α(1 → 2) linkages between sugar moieties. This mannosyltransferase evidently extends α(1 → 2) mannan by adding another α(1 → 2)-linked mannosyl residue. Its activity is appropriate for a role in synthesis of "high mannose" oligosaccharide moieties of glycoproteins.Key words: virulence, capsular polysaccharide, acapsular mutants, dolichol pathway, oligomannans.
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Yoshida-Moriguchi, Takako, Tobias Willer, Mary E. Anderson, David Venzke, Tamieka Whyte, Francesco Muntoni, Hane Lee, Stanley F. Nelson, Liping Yu i Kevin P. Campbell. "SGK196 Is a Glycosylation-Specific O-Mannose Kinase Required for Dystroglycan Function". Science 341, nr 6148 (8.08.2013): 896–99. http://dx.doi.org/10.1126/science.1239951.
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Phosphorylated O-mannosyl trisaccharide [N-acetylgalactosamine–β3-N-acetylglucosamine–β4-(phosphate-6-)mannose] is required for dystroglycan to bind laminin-G domain–containing extracellular proteins with high affinity in muscle and brain. However, the enzymes that produce this structure have not been fully elucidated. We found that glycosyltransferase-like domain–containing 2 (GTDC2) is a protein O-linked mannose β 1,4-N-acetylglucosaminyltransferase whose product could be extended by β 1,3-N-acetylgalactosaminyltransferase2 (B3GALNT2) to form the O-mannosyl trisaccharide. Furthermore, we identified SGK196 as an atypical kinase that phosphorylated the 6-position of O-mannose, specifically after the mannose had been modified by both GTDC2 and B3GALNT2. These findings suggest how mutations in GTDC2, B3GALNT2, and SGK196 disrupt dystroglycan receptor function and lead to congenital muscular dystrophy.
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Driessen, Nicole N., Esther J. M. Stoop, Roy Ummels, Sudagur S. Gurcha, Arun K. Mishra, Gérald Larrouy-Maumus, Jérôme Nigou i in. "Mycobacterium marinum MMAR_2380, a predicted transmembrane acyltransferase, is essential for the presence of the mannose cap on lipoarabinomannan". Microbiology 156, nr 11 (1.11.2010): 3492–502. http://dx.doi.org/10.1099/mic.0.037507-0.
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Lipoarabinomannan (LAM) is a major glycolipid in the mycobacterial cell envelope. LAM consists of a mannosylphosphatidylinositol (MPI) anchor, a mannan core and a branched arabinan domain. The termini of the arabinan branches can become substituted with one to three α(1→2)-linked mannosyl residues, the mannose cap, producing ManLAM. ManLAM has been associated with a range of different immunomodulatory properties of Mycobacterium tuberculosis during infection of the host. In some of these effects, the presence of the mannose cap on ManLAM appears to be crucial for its activity. So far, in the biosynthesis of the mannose cap on ManLAM, two enzymes have been reported to be involved: a mannosyltransferase that adds the first mannosyl residue of the mannose caps to the arabinan domain of LAM, and another mannosyltransferase that elongates the mannose cap up to three mannosyl residues. Here, we report that a third gene is involved, MMAR_2380, which is the Mycobacterium marinum orthologue of Rv1565c. MMAR_2380 encodes a predicted transmembrane acyltransferase. In M. marinum ΔMMAR_2380, the LAM arabinan domain is still intact, but the mutant LAM lacks the mannose cap. Additional effects of mutation of MMAR_2380 on LAM were observed: a higher degree of branching of both the arabinan domain and the mannan core, and a decreased incorporation of [1,2-14C]acetate into the acyl chains in mutant LAM as compared with the wild-type form. This latter effect was also observed for related lipoglycans, i.e. lipomannan (LM) and phosphatidylinositol mannosides (PIMs). Furthermore, the mutant strain showed increased aggregation in liquid cultures as compared with the wild-type strain. All phenotypic traits of M. marinum ΔMMAR_2380, the deficiency in the mannose cap on LAM and changes at the cell surface, could be reversed by complementing the mutant strain with MMAR_2380. Strikingly, membrane preparations of the mutant strain still showed enzymic activity for the arabinan mannose-capping mannosyltransferase similar to that of the wild-type strain. Although the exact function of MMAR_2380 remains unknown, we show that the protein is essential for the presence of a mannose cap on LAM.
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Yoshida-komiya, Hiromi, Daulat Ram P. Tulsiani, Toshio Hirayama i Yoshihiko Araki. "Mannose-binding molecules of rat spermatozoa and sperm–egg interaction". Zygote 7, nr 4 (listopad 1999): 335–46. http://dx.doi.org/10.1017/s096719949900074x.
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We have previously reported the occurrence and partial characterisation of an α-D-mannosidase activity on plasma membranes of rat, mouse, hamster and human spermatozoa. A soluble isoform of the rat sperm surface mannosidase was purified and polyclonal antibody raised. Since several reports have suggested that mannosyl residues on the rat, mouse and human zona pellucida may be involved in sperm-zona binding, studies were undertaken to examine the receptor-like role of mannose-binding molecules on rat spermatozoa. Sprague-Dawley rats (25–30-days old) were superovulated and eggs collected from the oviduct were treated with 0.3% hyaluronidase to remove the cumulus cells. Spermatozoa, collected from the cauda epididymis were capacitated for 5 h at 37 °C in 5% CO2 in air. The sperm–zona binding assay was performed in the presence of increasing concentrations of several sugars as well as preimmune and immune (anti-mannosidase or anti-mannose binding protein) IgG. Data from these studies show that: (1) significantly fewer sperm bound per egg in the presence of competitive inhibitors of mannosidase; (2) among the sugars examined, D-mannose was the most potent inhibitor causing 70% reduction in the number of sperm bound per egg; (3) anti-mannosidase or anti-mannose binding protein (but not preimmune) IgG showed a dose-dependent reduction in the number of sperm bound per egg; (4) anti-mannosidase IgG (but not anti-mannose binding protein IgG) showed a dose-dependent inhibition of sperm surface mannosidase activity; (5) the competitive inhibitors of mannosidase or the immune IgG had no effect on sperm motility or the sperm acrosome reaction. These results suggest that mannose-binding molecule(s) such as α-D-mannosidase or mannose-binding protein on the spermatozoa may recognise mannosyl residues on zona pellucida, and play a receptor-like role in sperm-egg interaction in the rat.
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Cao, Huan, Heather J. Wassall, Megan A. Forrester, Lindsay S. Hall, Heather M. Wilson, Jenna Shepherd, Bhinal Patel i in. "Hemoglobin S Induces Exposure of Red Blood Cell Membrane Skeleton Microdomains Bearing Mannose That Stimulate Phagocytosis By Macrophages: A Molecular Basis for Hemolysis in Sickle Cell Disease but Protection Against Plasmodium Falciparum malaria". Blood 132, Supplement 1 (29.11.2018): 3642. http://dx.doi.org/10.1182/blood-2018-99-117290.
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Abstract Heterozygosity for Hemoglobin (Hb) S, sickle cell trait (SCT), affects over 40 million people and confers resistance to severe infection by Plasmodium falciparum. Homozygosity for HbS, or compound heterozygosity with certain other alleles of Hb, affects over 4 million individuals and causes sickle cell disease (SCD). Hemolytic anaemia is a prominent feature of SCD and is mainly extravascular, mediated by hepatic and splenic macrophages. No ligands for this process have been identified. As many macrophage phagocytic receptors recognise carbohydrates, we surveyed surface glycan expression by sickle cells using a panel of 8 lectins and flow cytometry. Most glycans were similar to those of healthy red blood cells (RBC), except much higher expression of terminal mannose. We investigated the structural basis for these residues using glycomic mass spectroscopy, which showed them to be N-linked high (Man5-9GlcNAc2) mannoses, a surprising conclusion as these are usually intermediates in the formation of complex glycans and not displayed on cell surfaces. High resolution microscopy revealed the mannose residues to be carried in discrete microdomains on the surfaces of sickle cells. These structures were absent on the surfaces of healthy RBC, instead being present in the membrane skeleton under the cell surface. Lectin blots and immunoprecipitation showed the mannoses to co-migrate predominantly with spectrin. We showed these mannose-bearing structures were able to stimulate phagocytosis of RBC by using a peripheral blood derived macrophage uptake assay. Sickle RBC were taken up at high rates compared to healthy RBC and this could be inhibited by congeners of mannose. We identified the importance of a cognate ligand (CD206: the mannose receptor) using blocking antibodies and knockdown of CD206 expression using siRNA. The in vivo and pathogenic relevance of mannose exposure was investigated by taking advantage of the heterogeneity of hemolysis in SCD. RBC with SCD (n=94), SCT (n=57) and healthy individuals (n=54) were assayed for mannose exposure by flow cytometry. SCT and healthy RBC showed no mannose exposure but high levels were found on HbSS RBC (p<0.0001). Co-incident inheritance of HbSS with higher HbF values and alleles encoding alpha-thalassaemia resulted in lower surface mannose values. Overall, markers of hemolysis (RBC count, haemoglobin, reticulocyte count) correlated well with mannose exposure (Spearman correlation coefficients -0.68, -0.40, 0.37; p=0.0001, 0.0032, 0.0063 respectively). Plasma LDH is a marker of intravascular hemolysis and correlated with overall hemolysis within SCD (r=-0.25, p=0.016), but not mannose exposure (r=0.14, p=0.19). Thus mannose exposure correlated only with extravascular hemolysis. Identification of a ligand pair mediating rapid clearance of sickle cells raised the possibility that they also mediate enhanced clearance of SCT RBC infected by malarial parasites. Indeed, P. falciparum cultures induced mannose expression at the pigmented trophozoite and schizont stages in infected HbAA RBCs, at levels corresponding to mild hemolysis in SCD. Mannose expression in infected HbAS RBCs was even higher, with levels corresponding to severe hemolysis in SCD. Infection with P. falciparum and selection for HbS arose only recently in human evolution, raising the question of what the physiological triggers for this mechanism are. Infection with malarial parasites causes oxidative stress. We therefore subjected healthy RBC to copper sulphate, which resulted in surface mannose exposure as well as uptake by macrophages. Oxidized SCT RBC displayed more mannose than oxidized healthy RBC. Thus, we have identified a new cell surface 'eat me' signalling mechanism that allows inspecting macrophages to engage with the rigid membrane skeleton and phagocytose the mannose displaying cell. The mechanism is stimulated by HbS: when present in high concentrations, the mechanism is activated constitutively, resulting in sickle cell anaemia. Heterozygosity for HbS is insufficient by itself to trigger mannose exposure. However, the mechanism is primed so that oxidative stress associated with infection by P. falciparum causes greater mannose display, increased parasitized cell clearance and protection against severe malaria. These findings should allow the design of inhibitors of sickle cell haemolysis and inducers of protection against malaria. Disclosures Cao: University of Aberdeen: Patents & Royalties. Barker:University of Aberdeen: Patents & Royalties. Vickers:University of Aberdeen: Patents & Royalties; GSK: Equity Ownership.
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Paurević, Marija, Martina Šrajer Gajdošik i Rosana Ribić. "Mannose Ligands for Mannose Receptor Targeting". International Journal of Molecular Sciences 25, nr 3 (23.01.2024): 1370. http://dx.doi.org/10.3390/ijms25031370.
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The mannose receptor (MR, CD 206) is an endocytic receptor primarily expressed by macrophages and dendritic cells, which plays a critical role in both endocytosis and antigen processing and presentation. MR carbohydrate recognition domains (CRDs) exhibit a high binding affinity for branched and linear oligosaccharides. Furthermore, multivalent mannose presentation on the various templates like peptides, proteins, polymers, micelles, and dendrimers was proven to be a valuable approach for the selective and efficient delivery of various therapeutically active agents to MR. This review provides a detailed account of the most relevant and recent aspects of the synthesis and application of mannosylated bioactive formulations for MR-mediated delivery in treatments of cancer and other infectious diseases. It further highlights recent findings related to the necessary structural features of the mannose-containing ligands for successful binding to the MR.
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Keiser, Tracy L., Abul K. Azad, Evelina Guirado, Robert Bonacci i Larry S. Schlesinger. "Comparative Transcriptional Study of the Putative Mannose Donor Biosynthesis Genes in Virulent Mycobacterium tuberculosis and Attenuated Mycobacterium bovis BCG Strains". Infection and Immunity 79, nr 11 (6.09.2011): 4668–73. http://dx.doi.org/10.1128/iai.05635-11.
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ABSTRACTMycobacterium tuberculosiscontains mannosylated cell wall components which are important in macrophage recognition and response. The building block for the mannosyl constituents of these components is GDP-mannose, which is synthesized through a series of enzymes involved in the mannose donor biosynthesis pathway. Nothing is known about the expression levels of the genes encoding these enzymes during the course of infection. To generate transcriptional profiles for the mannose donor biosynthesis genes from virulentM. tuberculosisand attenuatedMycobacterium bovisBCG, bacteria were grown in broth culture and within human macrophages. Our results with broth-grown bacteria show that there are differences in expression of the selected genes betweenM. tuberculosisand BCG, with increased expression ofmanCinM. tuberculosisandmanAin BCG during stationary-phase growth. Results forM. tuberculosisextracted from within macrophages show thatwhiB2is highly expressed andmanBandmanCare moderately expressed during infection.Rv3256c,Rv3258c, andppm1have high expression levels early and decreased expression as the infection progresses. Results with BCG show that, as inM. tuberculosis,whiB2is highly expressed throughout infection, whereas there is either low expression or little change in expression of the remaining genes studied. Overall, our results show that there is differential regulation of expression of several genes in the mannose donor biosynthesis pathway ofM. tuberculosisand BCG grown in broth and within macrophages, raising the possibility that the level of mannose donors may vary during the course of infection and thereby impact the biosynthesis of mannose-containing cell wall molecules.
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Peng, Xuan, Jun Sun, Chris Michiels, Dirk Iserentant i Hubert Verachtert. "Decrease in Cell Surface Galactose Residues ofSchizosaccharomyces pombe Enhances Its Coflocculation with Pediococcus damnosus". Applied and Environmental Microbiology 67, nr 8 (1.08.2001): 3413–17. http://dx.doi.org/10.1128/aem.67.8.3413-3417.2001.
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ABSTRACT Pediococcus damnosus can coflocculate withSaccharomyces cerevisiae and cause beer acidification that may or may not be desired. Similar coflocculations occur with other yeasts except for Schizosaccharomyces pombe which has galactose-rich cell walls. We compared coflocculation rates ofS. pombe wild-type species TP4-1D, having a mannose-to-galactose ratio (Man:Gal) of 5 to 6 in the cell wall, with its glycosylation mutants gms1-1 (Man:Gal = 5:1) and gms1Δ (Man:Gal = 1:0). These mutants coflocculated at a much higher level (30 to 45%) than that of the wild type (5%). Coflocculation of the mutants was inhibited by exogenous mannose but not by galactose. The S. cerevisiae mnn2 mutant, with a mannan content similar to that ofgms1Δ, also showed high coflocculation (35%) and was sensitive to mannose inhibition. Coflocculation of P. damnosus and gms1Δ (or mnn2) also could be inhibited by gms1Δ mannan (with unbranched α-1,6-linked mannose residues), concanavalin A (mannose and glucose specific), or NPA lectin (specific for α-1,6-linked mannosyl units). Protease treatment of the bacterial cells completely abolished coflocculation. From these results we conclude that mannose residues on the cell surface of S. pombe serve as receptors for a P. damnosuslectin but that these receptors are shielded by galactose residues in wild-type strains. Such interactions are important in the production of Belgian acid types of beers in which mixed cultures are used to improve flavor.
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Rip, Jack W., Joyce A. Williams, Dean C. Crick, Robert T. Rymerson i Kenneth K. Carroll. "Biosynthesis of glycosylated dolichol intermediates and asparagine-linked glycoproteins during the germination of soybean seed embryos". Biochemistry and Cell Biology 67, nr 7 (1.07.1989): 377–83. http://dx.doi.org/10.1139/o89-059.
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Soybean embryos germinated in the presence of [14C]glucose or [14C]mannose incorporated considerable radioactivity into chloroform–methanol (2:1) (CM) soluble and chloroform–methanol–water (10:10:3) (CMW) soluble and insoluble components. The amount of [14C]mannosyl dolichyl phosphate in CM extracts increased over the 24 h of germination, while their [14C]glucosyl dolichyl phosphate content increased up to about 7 h. Incorporation of glucose exceeded incorporation of mannose by about fivefold. The amount of mannose- and glucose-labeled oligosaccharyl dolichyl pyrophosphates in CMW-soluble extracts increased during germination and, based on Concanavalin A Sepharose binding, never exceeded 2% of the total label incorporated into CM-soluble and CMW-soluble, and CMW-insoluble components combined. Nearly equal amounts of [14C]glucose and [14C]mannose appear in oligosaccharyl dolichyl pyrophosphates in the CMW-soluble fraction. Although the CMW-insoluble component contained the largest single amount of radioactivity from either sugar, much of it was not in protein. The protein content of embryos increased during germination, as did the incorporation of [14C]mannose into concanavalin A binding and nonbinding proteins. Microsomes isolated from nongerminated and germinated embryos contained (i) a dolichol kinase, (ii) glycosyl transferases required for the formation of oligosaccharyl dolichyl pyrophosphates, and (iii) a phosphatase which acts on dolichyl phosphate. Kinase activity doubled in 20 h, while phosphatase activity remained at the relatively high initial level. Activity of all three glycosyl transferases was highest after 2 h of germination, but decreased back to zero-time levels by 20 h. The N-acetylglucosaminyl, mannosyl, and glucosyl transferase activities were initially present in a ratio of about 1:10:40 and this ratio did not change appreciably over the period of observation.Key words: dolichol, dolichyl phosphate, glycosyl transferases, oligosaccharyl dolichyl pyrophosphate, soybean seed embryo germination.
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Eshun, Gaddi B., Heather A. Crapo, Idris Yazgan, Lauren Cronmiller i Omowunmi A. Sadik. "Sugar–Lectin Interactions for Direct and Selective Detection of Escherichia coli Bacteria Using QCM Biosensor". Biosensors 13, nr 3 (3.03.2023): 337. http://dx.doi.org/10.3390/bios13030337.
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Pathogenic Escherichia coli (E. coli) remains a safety concern in the preservation and quality of green leafy vegetables. Sugar–lectin interactions provide a reliable, specific, and effective sensing platform for the detection of bacteria as compared to the tedious conventional plate counting technique. Herein, we present the synthesis of 4-(N-mannosyl) benzoic acid (4-NMBA) and 4-thiophenyl-N-mannose (4-TNM) via a two-step reductive amination for the detection of E. coli using a quartz crystal microbalance (QCM) biosensor. The 4-NMBA was synthesized with mannose and para-aminobenzoic (4-PBA), while the 4-TNM was synthesized with mannose and 4-aminophenyl disulfide (4-AHP) using water and acetic acid in a 1:1 ratio. The resultant structure of mannose derivatives (4-NMBA and 4-TNM) was characterized and confirmed using analytical tools, such as Mass Spectrometer, SEM, and FTIR. The choice of ligands (mannose derivatives) is ascribed to the specific recognition of mannose to the FimH lectin of the type 1 pilus of E. coli. Furthermore, the 4-PBA and 4-AHP conjugated to mannose increase the ligand affinity to FimH lectins. The setup of the QCM biosensor was composed of modification of the crystal surface and the covalent attachment of ligands for the detection of E. coli. The piezoelectric effect (frequency shift of the quartz) was proportional to the change in mass added to the gold crystal surface. Both the 4-NMBA- and 4-TNM-coated QCM sensors had a limit of detection of 3.7 CFU/mL and 6.6 CFU/mL with a sensitivity of 2.56 × 103 ng/mL and 8.99 × 10−5 ng/mL, respectively, within the dynamic range of 103 to 106 CFU/mL. This study demonstrates the application of ligand-coated QCM biosensors as a cost-effective, simple, and label-free technology for monitoring pathogenic bacteria via molecular interactions on crystal surfaces.
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Michalak, Leszek, Sabina Leanti La Rosa, Shaun Leivers, Lars Jordhøy Lindstad, Åsmund Kjendseth Røhr, Finn Lillelund Aachmann i Bjørge Westereng. "A pair of esterases from a commensal gut bacterium remove acetylations from all positions on complex β-mannans". Proceedings of the National Academy of Sciences 117, nr 13 (13.03.2020): 7122–30. http://dx.doi.org/10.1073/pnas.1915376117.
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β-mannans and xylans are important components of the plant cell wall and they are acetylated to be protected from degradation by glycoside hydrolases. β-mannans are widely present in human and animal diets as fiber from leguminous plants and as thickeners and stabilizers in processed foods. There are many fully characterized acetylxylan esterases (AcXEs); however, the enzymes deacetylating mannans are less understood. Here we present two carbohydrate esterases, RiCE2 and RiCE17, from the Firmicute Roseburia intestinalis, which together deacetylate complex galactoglucomannan (GGM). The three-dimensional (3D) structure of RiCE17 with a mannopentaose in the active site shows that the CBM35 domain of RiCE17 forms a confined complex, where the axially oriented C2-hydroxyl of a mannose residue points toward the Ser41 of the catalytic triad. Cavities on the RiCE17 surface may accept galactosylations at the C6 positions of mannose adjacent to the mannose residue being deacetylated (subsite −1 and +1). In-depth characterization of the two enzymes using time-resolved NMR, high-performance liquid chromatography (HPLC), and mass spectrometry demonstrates that they work in a complementary manner. RiCE17 exclusively removes the axially oriented 2-O-acetylations on any mannose residue in an oligosaccharide, including double acetylated mannoses, while the RiCE2 is active on 3-O-, 4-O-, and 6-O-acetylations. Activity of RiCE2 is dependent on RiCE17 removing 2-O-acetylations from double acetylated mannose. Furthermore, transacetylation of oligosaccharides with the 2-O-specific RiCE17 provided insight into how temperature and pH affects acetyl migration on manno-oligosaccharides.
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Smith, D. J., A. Proudfoot, L. Friedli, L. S. Klig, G. Paravicini i M. A. Payton. "PMI40, an intron-containing gene required for early steps in yeast mannosylation". Molecular and Cellular Biology 12, nr 7 (lipiec 1992): 2924–30. http://dx.doi.org/10.1128/mcb.12.7.2924-2930.1992.
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We have previously described a temperature-sensitive pmi40-1 mutant of Saccharomyces cerevisiae which is defective in glycosylation and secretion because of a thermolabile phosphomannose isomerase (PMI) activity. Inactivation of PMI at the restrictive temperature of 37 degrees C prevents synthesis of the GDP-mannose and dolichol-phosphate-mannose required for a number of critical mannosyl transfer reactions and results in cell death. Here, we report the isolation of the PMI40 gene by complementation of the corresponding mutation. The PMI40 gene contains an efficiently spliced intron which differs from the majority of those so far identified in S. cerevisiae in that it is short and the branch-forming structure has an AACTAAC motif replacing the highly conserved consensus TACTAAC. The 48.2-kDa protein predicted to be encoded by PMI40 contains amino acid sequences corresponding to those of internal peptides derived from purified S. cerevisiae PMI. Deletion of the PMI40 coding sequence results in a strain requiring D-mannose for growth. The PMI40 gene is located on chromosome V, and its transcription is increased 12-fold when cells are grown on D-mannose as sole carbon source instead of D-glucose. PMI enzyme activity, however, is not increased in D-mannose-grown cells, and PMI protein levels remain constant, suggesting that the PMI40 gene is subject to additional levels of regulation.
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Smith, D. J., A. Proudfoot, L. Friedli, L. S. Klig, G. Paravicini i M. A. Payton. "PMI40, an intron-containing gene required for early steps in yeast mannosylation." Molecular and Cellular Biology 12, nr 7 (lipiec 1992): 2924–30. http://dx.doi.org/10.1128/mcb.12.7.2924.
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We have previously described a temperature-sensitive pmi40-1 mutant of Saccharomyces cerevisiae which is defective in glycosylation and secretion because of a thermolabile phosphomannose isomerase (PMI) activity. Inactivation of PMI at the restrictive temperature of 37 degrees C prevents synthesis of the GDP-mannose and dolichol-phosphate-mannose required for a number of critical mannosyl transfer reactions and results in cell death. Here, we report the isolation of the PMI40 gene by complementation of the corresponding mutation. The PMI40 gene contains an efficiently spliced intron which differs from the majority of those so far identified in S. cerevisiae in that it is short and the branch-forming structure has an AACTAAC motif replacing the highly conserved consensus TACTAAC. The 48.2-kDa protein predicted to be encoded by PMI40 contains amino acid sequences corresponding to those of internal peptides derived from purified S. cerevisiae PMI. Deletion of the PMI40 coding sequence results in a strain requiring D-mannose for growth. The PMI40 gene is located on chromosome V, and its transcription is increased 12-fold when cells are grown on D-mannose as sole carbon source instead of D-glucose. PMI enzyme activity, however, is not increased in D-mannose-grown cells, and PMI protein levels remain constant, suggesting that the PMI40 gene is subject to additional levels of regulation.
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Tankrathok, Anupong, Javier Iglesias-Fernández, Sukanya Luang, Robert C. Robinson, Atsuo Kimura, Carme Rovira, Maria Hrmova i James R. Ketudat Cairns. "Structural analysis and insights into the glycon specificity of the rice GH1 Os7BGlu26 β-D-mannosidase". Acta Crystallographica Section D Biological Crystallography 69, nr 10 (20.09.2013): 2124–35. http://dx.doi.org/10.1107/s0907444913020568.
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Rice Os7BGlu26 is a GH1 family glycoside hydrolase with a threefold higherkcat/Kmvalue for 4-nitrophenyl β-D-mannoside (4NPMan) compared with 4-nitrophenyl β-D-glucoside (4NPGlc). To investigate its selectivity for β-D-mannoside and β-D-glucoside substrates, the structures of apo Os7BGlu26 at a resolution of 2.20 Å and of Os7BGlu26 with mannose at a resolution of 2.45 Å were elucidated from isomorphous crystals in space groupP212121. The (β/α)8-barrel structure is similar to other GH1 family structures, but with a narrower active-site cleft. The Os7BGlu26 structure with D-mannose corresponds to a product complex, with β-D-mannose in the1S5skew-boat conformation. Docking of the1S3,1S5,2SOand3S1pyranose-ring conformations of 4NPMan and 4NPGlc substrates into the active site of Os7BGlu26 indicated that the lowest energies were in the1S5and1S3skew-boat conformations. Comparison of these docked conformers with other rice GH1 structures revealed differences in the residues interacting with the catalytic acid/base between enzymes with and without β-D-mannosidase activity. The mutation of Tyr134 to Trp in Os7BGlu26 resulted in similarkcat/Kmvalues for 4NPMan and 4NPGlc, while mutation of Tyr134 to Phe resulted in a 37-fold higherkcat/Kmfor 4NPMan than 4NPGlc. Mutation of Cys182 to Thr decreased both the activity and the selectivity for β-D-mannoside. It was concluded that interactions with the catalytic acid/base play a significant role in glycon selection.
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Sarkar, K., i P. K. Das. "Protective effect of neoglycoprotein-conjugated muramyl dipeptide against Leishmania donovani infection: the role of cytokines." Journal of Immunology 158, nr 11 (1.06.1997): 5357–65. http://dx.doi.org/10.4049/jimmunol.158.11.5357.
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Abstract Active targeting of muramyl dipeptide (MDP) to macrophages was studied by conjugation with the neoglycoprotein, mannosyl human serum albumin (mannose-HSA) using visceral leishmaniasis as the model macrophage disease. Conjugation did not decrease the affinity of the neoglycoprotein for macrophage mannose receptor. Mannose-HSA-MDP was 50 times more efficient than free MDP in inhibiting the growth of Leishmania donovani inside peritoneal macrophages. Moreover, in a 60-day murine model of visceral leishmaniasis, 95% of the spleen parasite burden was reduced by mannose-HSA-MDP at a dose of 0.5 mg/kg/day given for 4 days. Free MDP at a similar dose had very little effect. In vitro exposure of MDP caused enhanced generation of O2- by macrophages, whereas generation of nitric oxide (NO) was not induced. The elevated antileishmanial activity of MDP-treated macrophages in culture was abrogated by O2- scavengers. In contrast, considerably enhanced amounts of NO and O2- were generated from macrophages of mannose-HSA-MDP-treated animals, and their splenocytes secreted soluble factors providing all the signals required for the induction of NO biosynthesis. The increase in NO production was paralleled by a concomitant increase in antileishmanial activity, which was reversed by NO synthesis inhibitors. Splenocyte supernatants treated with anti-IFN-gamma or anti-TNF-alpha Abs suppressed inducible NO generation by macrophages. Moreover, i.v. administration of anti-IFN-gamma and anti-TNF-alpha along with mannose-HSA-MDP greatly reduced protection against L. donovani infection. Neoglycoprotein-conjugated MDP, therefore, activated mouse macrophages in vivo to kill L. donovani, and this may depend on the physiologic generation of NO induced by IFN-gamma and TNF-alpha.
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Vickers, Mark A., Robert N. Barker, Huan Cao, Heather J. Wassall, Megan A. Forrester, Lindsay S. Hall, Michael Moss i in. "Exteriorisation of Mannoses on Human Erythrocyte Membrane Skeleton Provides 'Eat Me' Signals for Oxidatively Damaged Cells to be Cleared By Macrophages: A Pathway Mediating Hemolysis in Sickle Cell Disease". Blood 130, Suppl_1 (7.12.2017): 919. http://dx.doi.org/10.1182/blood.v130.suppl_1.919.919.
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Abstract The disposal of unwanted or dying cells is a key biological process driven by the display of 'eat me' signals that are recognised by phagocytes. Although these markers for uptake are known to include certain lipids and proteins, the role of glycans, which are abundant on cell surfaces, remains poorly characterized. Here, an unbiased glycomic survey by mass spectroscopic analyses of glycosidase (PNGase F) digested human red blood cell (RBC) membranes identified novel N-linked high mannose structures, which are sequestered inside healthy cells with spectrin, the major protein of the internal membrane skeleton, but exteriorised when cells are damaged as a dominant signal for uptake by macrophages. A panel of lectin probes was used to demonstrate that the mannose species were available as discrete patches on the surface of RBC that had been stressed by oxidation, but undetectable on unpermeabilized untreated cells. High mannoses co-localized with alpha-spectrin on lectin/Western blots and this signal was degraded by prior incubation with glycosidases. Super resolution microscopy showed co-localisation of mannose with spectrin in membrane protrusions of oxidized RBC. Co-localization of spectrin with N-linked mannose and exteriorisation on effete cells were also observed in nucleated cells. The mannose displayed on oxidized RBC represents a novel 'eat-me' signal for human cells, since congeners of mannose inhibited uptake by human monocyte-derived macrophages. The mannose receptor (CD206) was identified as an important receptor in this system by the use of blocking antibody and siRNA mediated knock-down. The mechanisms underlying the hemolysis characteristic of sickle cell disease (SCD) remain to be fully defined. We therefore investigated the contribution of this new pathway. RBC from patients with SCD demonstrated remarkably high levels of surface mannose, and super resolution microscopy showed the expression again to be limited to discrete patches and co-localized with spectrin in a disrupted membrane skeletal structure. The importance of mannose exposure to uptake of sickle cells by macrophages was confirmed by inhibition by congeners of mannose and blocking antibody to CD206. The prevalence of SCD is high because of selective pressure caused by the resistance of subjects with sickle cell trait to malarial parasites, which are mainly cleared by splenic macrophages. We therefore investigated whether RBC from subjects with sickle cell trait expressed surface mannose. We show that such RBC express modestly raised levels (p<.01, n=10 (Wilcoxon rank sum)). This excess surface mannose should predispose to parasitized RBC being cleared more rapidly in infected individuals and may cause the increasingly recognised clinical manifestations of sickle cell trait. We also investigated whether the degree of mannose exposure correlated with peripheral blood count parameters. The Pearson correlation coefficients of log transformed surface mannose expression with hemoglobin levels, red cell counts and reticulocyte counts were -0.83, -0.84 and 0.73 respectively (all p values <0.0001)(n=70, 30 patients with homozygous SS, 10 with AS, 30 with AA); it was noted that cells from patients taking hydroxycarbamide, who had concomitant alpha-thalassaemia or SC disease exhibited intermediate levels. In summary, our results reveal a previously undescribed cryptic mannose exteriorization pathway, which mediates disposal of oxidatively damaged cells. The pathway is constitutively activated in SCD, where it mediates haemolysis and the degree of activation correlates well with clinical phenotypes of SCD and sickle cell trait. It thus represents a new mechanism for possible future therapeutic intervention. Disclosures Vickers: University of Aberdeen: Patents & Royalties: About to apply for patent. Barker: University of Aberdeen: Employment, Patents & Royalties: About to apply for patent. Cao: University of Aberdeen: Patents & Royalties: About to apply for patent.
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Satoh, Tadashi, Nathan P. Cowieson, Wataru Hakamata, Hiroko Ideo, Keiko Fukushima, Masaaki Kurihara, Ryuichi Kato, Katsuko Yamashita i Soichi Wakatsuki. "Structural Basis for Recognition of High Mannose Type Glycoproteins by Mammalian Transport Lectin VIP36". Journal of Biological Chemistry 282, nr 38 (25.07.2007): 28246–55. http://dx.doi.org/10.1074/jbc.m703064200.
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VIP36 functions as a transport lectin for trafficking certain high mannose type glycoproteins in the secretory pathway. Here we report the crystal structure of VIP36 exoplasmic/luminal domain comprising a carbohydrate recognition domain and a stalk domain. The structures of VIP36 in complex with Ca2+ and mannosyl ligands are also described. The carbohydrate recognition domain is composed of a 17-stranded antiparallel β-sandwich and binds one Ca2+ adjoining the carbohydrate-binding site. The structure reveals that a coordinated Ca2+ ion orients the side chains of Asp131, Asn166, and His190 for carbohydrate binding. This result explains the Ca2+-dependent carbohydrate binding of this protein. The Man-α-1,2-Man-α-1,2-Man, which corresponds to the D1 arm of high mannose type glycan, is recognized by eight residues through extensive hydrogen bonds. The complex structures reveal the structural basis for high mannose type glycoprotein recognition by VIP36 in a Ca2+-dependent and D1 arm-specific manner.
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Zhou, Peng, Yang Liu, Qiaojuan Yan, Zhongzhou Chen, Zhen Qin i Zhengqiang Jiang. "Structural insights into the substrate specificity and transglycosylation activity of a fungal glycoside hydrolase family 5 β-mannosidase". Acta Crystallographica Section D Biological Crystallography 70, nr 11 (23.10.2014): 2970–82. http://dx.doi.org/10.1107/s1399004714019762.
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β-Mannosidases are exo-acting glycoside hydrolases (GHs) that catalyse the removal of the nonreducing end β-D-mannose from manno-oligosaccharides or mannoside-substituted molecules. They play important roles in fundamental biological processes and also have potential applications in various industries. In this study, the first fungal GH family 5 β-mannosidase (RmMan5B) fromRhizomucor mieheiwas functionally and structurally characterized.RmMan5B exhibited a much higher activity against manno-oligosaccharides than againstp-nitrophenyl β-D-mannopyranoside (pNPM) and had a transglycosylation activity which transferred mannosyl residues to sugars such as fructose. To investigate its substrate specificity and transglycosylation activity, crystal structures ofRmMan5B and of its inactive E202A mutant in complex with mannobiose, mannotriose and mannosyl-fructose were determined at resolutions of 1.3, 2.6, 2.0 and 2.4 Å, respectively. In addition, the crystal structure ofR. mieheiβ-mannanase (RmMan5A) was determined at a resolution of 2.3 Å. BothRmMan5A andRmMan5B adopt the (β/α)8-barrel architecture, which is globally similar to the other members of GH family 5. However,RmMan5B shows several differences in the loop around the active site. The extended loop between strand β8 and helix α8 (residues 354–392) forms a `double' steric barrier to `block' the substrate-binding cleft at the end of the −1 subsite. Trp119, Asn260 and Glu380 in the β-mannosidase, which are involved in hydrogen-bond contacts with the −1 mannose, might be essential for exo catalytic activity. Moreover, the structure of RmMan5B in complex with mannosyl-fructose has provided evidence for the interactions between the β-mannosidase and D-fructofuranose. Overall, the present study not only helps in understanding the catalytic mechanism of GH family 5 β-mannosidases, but also provides a basis for further enzymatic engineering of β-mannosidases and β-mannanases.
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Sullenbarger, BA, MS Petitt, P. Chong, MW Long i MS Wicha. "Murine granulocytic cell adhesion to bone marrow hemonectin is mediated by mannose and galactose". Blood 86, nr 1 (1.07.1995): 135–40. http://dx.doi.org/10.1182/blood.v86.1.135.bloodjournal861135.
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Hemonectin (HN) is a bone marrow (BM) protein that promotes specific attachment of immature granulocytes and their precursors within the BM. We report that HN is a glycoprotein containing both mannose and galactose residues, and provide evidence that these carbohydrates mediate granulocytic cell adhesion to HN. Carbohydrate structure was determined by digoxigenin-conjugated lectin binding to HN and indicated the presence of mannose, galactose, sialic acid, and the absence of fucose-linked oligosaccharides. The role of carbohydrates in mediating cell adhesion was examined by chemical and enzymatic deglycosylation. Deglycosylation of HN with trifluoromethanesulfonic acid, which cleaves N- and O-linked oligosaccharides, inhibits 66% of cell attachment to HN, and results in an apparent decrease in molecular weight from 60 to 50 kD. Enzymatic deglycosylation with endo-B-N-acetylglucosaminidase H, which hydrolyzes specific N-linked mannose residues, inhibits 30% of cell adhesion to HN. Finally, the role of these specific sugars in hemonectin-mediated cell adhesion was confirmed with neoglycoprotein blocking. Preincubation of BM cells with mannosyl- and galactosyl-BSA probes produces a dose-dependent inhibition of cell attachment to HN, whereas fucosyl-BSA does not inhibit cell adhesion to HN. These results show that mannose and galactose partially mediate adhesion of BM granulocytes to HN.
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Barre, Annick, Yves Bourne, Els Van Damme i Pierre Rougé. "Overview of the Structure–Function Relationships of Mannose-Specific Lectins from Plants, Algae and Fungi". International Journal of Molecular Sciences 20, nr 2 (10.01.2019): 254. http://dx.doi.org/10.3390/ijms20020254.
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To date, a number of mannose-binding lectins have been isolated and characterized from plants and fungi. These proteins are composed of different structural scaffold structures which harbor a single or multiple carbohydrate-binding sites involved in the specific recognition of mannose-containing glycans. Generally, the mannose-binding site consists of a small, central, carbohydrate-binding pocket responsible for the “broad sugar-binding specificity” toward a single mannose molecule, surrounded by a more extended binding area responsible for the specific recognition of larger mannose-containing N-glycan chains. Accordingly, the mannose-binding specificity of the so-called mannose-binding lectins towards complex mannose-containing N-glycans depends largely on the topography of their mannose-binding site(s). This structure–function relationship introduces a high degree of specificity in the apparently homogeneous group of mannose-binding lectins, with respect to the specific recognition of high-mannose and complex N-glycans. Because of the high specificity towards mannose these lectins are valuable tools for deciphering and characterizing the complex mannose-containing glycans that decorate both normal and transformed cells, e.g., the altered high-mannose N-glycans that often occur at the surface of various cancer cells.
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Sharma, Vandana, i Hudson H. Freeze. "Mannose Efflux from the Cells". Journal of Biological Chemistry 286, nr 12 (27.01.2011): 10193–200. http://dx.doi.org/10.1074/jbc.m110.194241.
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All mammals have 50–100 μm mannose in their blood. However, the source of the dynamic pool of mannose in blood is unknown. Most of it is thought to be derived from glucose in the cells. We studied mannose uptake and release by various cell types. Interestingly, our results show that mannose taken up by the cells through transporters is handled differently from the mannose released within the cells due to glycan processing of protein-bound oligosaccharides. Although more than 95% of incoming mannose is catabolized, most of the mannose released by intracellular processing is expelled from the cells as free mannose predominantly via a nocodazole-sensitive sugar transporter. Under physiological conditions, incoming mannose is more accessible to hexokinase, whereas mannose released within the cells is protected from HK and therefore has a different fate. Our data also suggest that generation of free mannose due to the processing of glycoconjugates composed of glucose-derived mannose and its efflux from the cells can account for most of the mannose found in blood and its steady state maintenance.
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Morita, Yasu S., Chubert B. C. Sena, Ross F. Waller, Ken Kurokawa, M. Fleur Sernee, Fumiki Nakatani, Ruth E. Haites i in. "PimE Is a Polyprenol-phosphate-mannose-dependent Mannosyltransferase That Transfers the Fifth Mannose of Phosphatidylinositol Mannoside in Mycobacteria". Journal of Biological Chemistry 281, nr 35 (27.06.2006): 25143–55. http://dx.doi.org/10.1074/jbc.m604214200.
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Romain, Félix, Cynthia Horn, Pascale Pescher, Abdelkader Namane, Michel Riviere, Germain Puzo, Octavian Barzu i Gilles Marchal. "Deglycosylation of the 45/47-Kilodalton Antigen Complex of Mycobacterium tuberculosis Decreases Its Capacity To Elicit In Vivo or In Vitro Cellular Immune Responses". Infection and Immunity 67, nr 11 (1.11.1999): 5567–72. http://dx.doi.org/10.1128/iai.67.11.5567-5572.1999.
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ABSTRACT A protection against a challenge with Mycobacterium tuberculosis is induced by previous immunization with living attenuated mycobacteria, usually bacillus Calmette-Guérin (BCG). The 45/47-kDa antigen complex (Apa) present in culture filtrates of BCG of M. tuberculosis has been identified and isolated based on its ability to interact mainly with T lymphocytes and/or antibodies induced by immunization with living bacteria. The protein is glycosylated. A large batch of Apa was purified from M. tuberculosis culture filtrate to determine the extent of glycosylation and its role on the expression of the immune responses. Mass spectrometry revealed a spectrum of glycosylated molecules, with the majority of species bearing six, seven, or eight mannose residues (22, 24, and 17%, respectively), while others three, four, or five mannoses (5, 9, and 14%, respectively). Molecules with one, two, or nine mannoses were rare (1.5, 3, and 3%, respectively), as were unglycosylated species (in the range of 1%). To eliminate the mannose residues linked to the protein, the glycosylated Apa molecules were chemically or enzymatically treated. The deglycosylated antigen was 10-fold less active than native molecules in eliciting delayed-type hypersensitivity reactions in guinea pigs immunized with BCG. It was 30-fold less active than native molecules when assayed in vitro for its capacity to stimulate T lymphocytes primed in vivo. The presence of the mannose residues on the Apa protein was essential for the antigenicity of the molecules in T-cell-dependent immune responses in vitro and in vivo.
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Stigliano, Ivan D., Solana G. Alculumbre, Carlos A. Labriola, Armando J. Parodi i Cecilia D'Alessio. "Glucosidase II and N-glycan mannose content regulate the half-lives of monoglucosylated species in vivo". Molecular Biology of the Cell 22, nr 11 (czerwiec 2011): 1810–23. http://dx.doi.org/10.1091/mbc.e11-01-0019.
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Glucosidase II (GII) sequentially removes the two innermost glucose residues from the glycan (Glc3Man9GlcNAc2) transferred to proteins. GII also participates in cycles involving the lectin/chaperones calnexin (CNX) and calreticulin (CRT) as it removes the single glucose unit added to folding intermediates and misfolded glycoproteins by the UDP-Glc:glycoprotein glucosyltransferase (UGGT). GII is a heterodimer in which the α subunit (GIIα) bears the active site, and the β subunit (GIIβ) modulates GIIα activity through its C-terminal mannose 6-phosphate receptor homologous (MRH) domain. Here we report that, as already described in cell-free assays, in live Schizosaccharomyces pombe cells a decrease in the number of mannoses in the glycan results in decreased GII activity. Contrary to previously reported cell-free experiments, however, no such effect was observed in vivo for UGGT. We propose that endoplasmic reticulum α-mannosidase–mediated N-glycan demannosylation of misfolded/slow-folding glycoproteins may favor their interaction with the lectin/chaperone CNX present in S. pombe by prolonging the half-lives of the monoglucosylated glycans (S. pombe lacks CRT). Moreover, we show that even N-glycans bearing five mannoses may interact in vivo with the GIIβ MRH domain and that the N-terminal GIIβ G2B domain is involved in the GIIα–GIIβ interaction. Finally, we report that protists that transfer glycans with low mannose content to proteins have nevertheless conserved the possibility of displaying relatively long-lived monoglucosylated glycans by expressing GIIβ MRH domains with a higher specificity for glycans with high mannose content.
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ROMERO, Pedro A., Marc LUSSIER, Anne-Marie SDICU, Howard BUSSEY i Annette HERSCOVICS. "Ktr1p is an α-1,2-mannosyltransferase of Saccharomyces cerevisiae. Comparison of the enzymic properties of soluble recombinant Ktr1p and Kre2p/Mnt1p produced in Pichia pastoris". Biochemical Journal 321, nr 2 (15.01.1997): 289–95. http://dx.doi.org/10.1042/bj3210289.
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The yeast genome contains a KRE2/MNT1 family of nine related genes with amino acid similarity to the α1,2-mannosyltransferase Kre2p/Mnt1p, the only member of this family whose enzymic properties have been studied. In this study, the enzymic properties of Ktr1p, another member of this family, were studied and compared to those of Kre2p/Mnt1p. Recombinant soluble forms of Kre2p/Mnt1p and Ktr1p lacking their N-terminal regions were expressed as secreted proteins from the methylotrophic yeast Pichia pastoris. After induction with methanol, the medium contained approx. 40 and 400 mg/l of soluble recombinant Kre2p/Mnt1p and Ktr1p respectively. Both recombinant proteins were shown to exhibit α1,2-mannosyltransferase activity. The enzymes have an absolute requirement for Mn2+ and a similar Km for mannose (280Ő350 mM), methyl-α-mannoside (60Ő90 mM) and GDP-mannose (50Ő90 ƁM), but the Vmax was approx. 10 times higher for Kre2p/Mnt1p than for Ktr1p. The enzymes have similar substrate specificities and utilize mannose, methyl-α-mannoside, α-1,2-mannobiose and methyl-α-1,2-mannobiose, as well as Man15Ő30GlcNAc, derived from mnn2 mutant glycoproteins, as substrates. The enzymes do not utilize α-1,6-mannobiose, α-1,6-mannotriose, α-1,6-mannotetraose, mammalian Man9GlcNAc or yeast Man9Ő10GlcNAc. These results indicate that Kre2p/Mnt1p and Ktr1p are capable of participating in both N-glycan and O-glycan biosynthesis.
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Ishida, Yoji, Kazunori Murai, Syugo Kowata, Tatsuo Oyake, Ryo Suzuki i Kazuo Maruyama. "Mannose Labeled Liposome-Encapsulated Doxorubicin Is Effective in the Management of Experimental Immune Thrombocytopenic Purpura Model Mice." Blood 108, nr 11 (16.11.2006): 3995. http://dx.doi.org/10.1182/blood.v108.11.3995.3995.
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Abstract Immune thrombocytopenic purpura (ITP) is an autoimuune disease in which platelet antibodies cause increased platelet consumption. The destruction of platelets is mediated by the reticuloendothelial system (RES), especially hepatic and splenic macrophages. The depletion of these cells was carried out by the intravenous injection of mannose labeled liposome-encapsulated doxorubicin (mannose-DXR-liposome). The reason why mannose labeled liposome was used was that the macrophage expressed mannose receptor on the surface. Therefore, mannose-DXR-liposome is considered to be phagocyted specifically by macrophages. In this study, we evaluated the effects of mannose-DXR-liposome in a mouse model of ITP. In vitro experiments: Murine peritoneal macrophages were obtained by the intraperitoneal injection of thioglycolate (TGC) to ddY mice. The uptake of fluorescence by peritoneal macrophages was measured using rhodamine-liposome by flow cytometry. The macrophages were incubated with mannose labeled rhodamine-liposome (mannose(+)-rhodamine-liposome) or mannose unlabeled rhodamine-liposome (mannose(−)-rhodamine-liposome) for 30 min at 37 °C. After washing with PBS, they were applied for flow cytometry. Rhodamine fluorescence intensity in macrophages was higher in mannose(+)-rhodamine-liposome treatment than that in mannose(−)-rhodamine-liposome treatment (Figure 1). The viability of peritoneal macrophages was measured by MTT assay after 30 min incubation with DXR-liposome. The viability in the treatment with mannose(+)-DXR-liposome was much less than that in the treatment with mannose(−)-DXR-liposome (Figure 2). In vivo experiment: Anti-mouse platelet serum (APS) was injected intraperitoneally to ddY mice at 24 hr after intravenous injection of mannose(+)-DXR-liposome or mannose(−)-DXR-liposome. Platelet count was measured at 12 hr after APS injection. It was 89.3 ± 22.1 x104 / μl (n=6) in mannose(+)-DXR-liposome treatment, while 4.5 ± 2.0 x104 / μl (n=8) in mannose(−)-DXR-liposome treatment. The platelet counts were 3.2 ± 0.5 x104 / μl (n=4), 96.1 ± 15.0 x104 / μl (n=4) or 99.3 ± 26.2 x104 / μl (n=4) in mice with only APS administration, mannose(+)-DXR-liposome+saline or mannose(−)-DXR-liposome+saline administrations instead of APS, respectively. These in vivo data indicated that APS induced thrombocytopenia was not observed in mice treated with mannose(+)-DXR-liposome, because of the destruction of macrophages by mannose(+)-DXR-liposome administration. These in vitro and in vivo results strongly suggest that mannose(+)-DXR-liposome treatment specifically delete the macrophages and can be effective in the management of experimental ITP model mice. Figure 1 The Uptake of Rhodamine –liposome by Murine Macrophages. Figure 1. The Uptake of Rhodamine –liposome by Murine Macrophages. Figure 2. The Viability of Murine Macrophages after incubation with Doxorubicin-liposome. Figure 2. The Viability of Murine Macrophages after incubation with Doxorubicin-liposome.
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Ishida, Yoji, Kazunori Murai, Tatsuo Oyake, Shugo Kowata, Shigeki Ito, Ryo Suzuki i Kazuo Maruyama. "Mannose Labeled Liposome Containing DXR Administration Is Effective in Reversing Thrombocytopenia in the Model Mouse of Immune Thrombocytopenia." Blood 110, nr 11 (16.11.2007): 2109. http://dx.doi.org/10.1182/blood.v110.11.2109.2109.
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Abstract Immune thrombocytopenia (ITP) is classified as an autoimmune disease in, which antibody-coated platelets are phagocytosed by macrophages in the reticuloendothelial system (RES) through Fc gamma receptor-mediated or complement-mediated pathways. Based on the the pathophysiology of ITP, described above, and evidences that macrophages expresses mannose receptor on their surface and that mannose-terminated human glucocerebrosidase is highly effective in ameliorating many of the clinical manifestations of Gaucher’s disease, we devised mannose labeled liposome containing DXR to eliminate specifically macrophages. In this study, we evaluated the effects of mannose labeled liposome containing DXR (liposome-DXR) in a mouse model of ITP. In vitro experiments: Murine peritoneal macrophages were obtained by the intra-peritoneal injection of thioglycolate (TGC) to ddY mice. The uptake of fluorescence by peritoneal macrophages was measured using rhodamine-liposome by flow cytometry. The macrophages were incubated with mannose labeled rhodamine-liposome {mannose(+)-rhodamine-liposome} or mannose unlabeled rhodamine-liposome {mannose(−)-rhodamine-liposome} for 30 min at 37°C. After washing with PBS, they were applied for flow cytometry. Rhodamine fluorescence intensity in macrophages was higher in incubation with mannose(+)-rhodamine-liposome than in incubation with mannose(−)-rhodamine-liposome treatment. The viability of peritoneal macrophages was measured by MTT assay after 30 min incubation with liposome-DXR. The viability in the incubation with mannose labeled liposome-DXR {mannose(+)-liposome-DXR} was much less than in the incubation with mannose unlabeled liposome-DXR {mannose(−)-liposome-DXR} (Figure 1). In vivo experiment: Anti-mouse platelet serum (APS) was injected intra-peritoneally to ddY mice at 24 hr after intravenous injection of mannose(+)-liposome-DXR or mannose(−)-liposome-DXR. Platelet counts were measured at 12 hr after APS injection. They were 89.3±22.1 × 104 /μl (n=6, p<0.01) in mannose(+)-liposome-DXR treatment, while 4.5±2.0 × 104 /μl (n=8) in mannose(−)-liposome-DXR treatment (Figure 2). The platelet counts were 3.2±0.5 × 104 /μl (n=4), 96.1±15.0 × 104 /μl (n=4) or 99.3±26.2 × 104/μl (n=4) in mice with only APS administration, mannose(+)-liposome-DXR+saline or mannose(−)-liposome-DXR+saline administrations instead of APS, respectively. These in vivo data indicated that APS induced thrombocytopenia was not observed in mice treated with mannose(+)-DXR-liposome, because of the destruction of macrophages by mannose(+)-DXR-liposome administration. These in vitro and in vivo data strongly suggest that mannose(+)-liposome-DXR may specifically delete the macrophages and and can be effective in the management of experimental ITP model mice. Figure 1. The Viability of Murine Macrophages after Incubation with Liposome-Doxorubicine Figure 1. The Viability of Murine Macrophages after Incubation with Liposome-Doxorubicine Figure 2. Platelet counts after APS injection Figure 2. Platelet counts after APS injection
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Rodrigues, Marta V., Nuno Borges, Carla P. Almeida, Pedro Lamosa i Helena Santos. "A Unique β-1,2-Mannosyltransferase of Thermotoga maritima That Uses Di-myo-Inositol Phosphate as the Mannosyl Acceptor". Journal of Bacteriology 191, nr 19 (31.07.2009): 6105–15. http://dx.doi.org/10.1128/jb.00598-09.
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ABSTRACT In addition to di-myo-inositol-1,3′-phosphate (DIP), a compatible solute widespread in hyperthermophiles, the organic solute pool of Thermotoga maritima comprises 2-(O-β-d-mannosyl)-di-myo-inositol-1,3′-phosphate (MDIP) and 2-(O-β-d-mannosyl-1,2-O-β-d-mannosyl)-di-myo-inositol-1,3′-phosphate (MMDIP), two newly identified β-1,2-mannosides. In cells grown under heat stress, MDIP was the major solute, accounting for 43% of the total pool; MMDIP and DIP accumulated to similar levels, each corresponding to 11.5% of the total pool. The synthesis of MDIP involved the transfer of the mannosyl group from GDP-mannose to DIP in a single-step reaction catalyzed by MDIP synthase. This enzyme used MDIP as an acceptor of a second mannose residue, yielding the di-mannosylated compound. Minor amounts of the tri-mannosylated form were also detected. With a genomic approach, putative genes for MDIP synthase were identified in the genome of T. maritima, and the assignment was confirmed by functional expression in Escherichia coli. Genes with significant sequence identity were found only in the genomes of Thermotoga spp., Aquifex aeolicus, and Archaeoglobus profundus. MDIP synthase of T. maritima had maximal activity at 95°C and apparent Km values of 16 mM and 0.7 mM for DIP and GDP-mannose, respectively. The stereochemistry of MDIP was characterized by isotopic labeling and nuclear magnetic resonance (NMR): DIP selectively labeled with carbon 13 at position C1 of the l-inositol moiety was synthesized and used as a substrate for MDIP synthase. This β-1,2-mannosyltransferase is unrelated to known glycosyltransferases, and within the domain Bacteria, it is restricted to members of the two deepest lineages, i.e., the Thermotogales and the Aquificales. To our knowledge, this is the first β-1,2-mannosyltransferase characterized thus far.
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De Blasio, Daiana, Stefano Fumagalli, Luca Longhi, Franca Orsini, Alessandro Palmioli, Matteo Stravalaci, Gloria Vegliante i in. "Pharmacological inhibition of mannose-binding lectin ameliorates neurobehavioral dysfunction following experimental traumatic brain injury". Journal of Cerebral Blood Flow & Metabolism 37, nr 3 (20.07.2016): 938–50. http://dx.doi.org/10.1177/0271678x16647397.
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Mannose-binding lectin is present in the contusion area of traumatic brain-injured patients and in that of traumatic brain-injured mice, where mannose-binding lectin-C exceeds mannose-binding lectin-A. The reduced susceptibility to traumatic brain injury of mannose-binding lectin double knock-out mice (mannose-binding lectin−/−) when compared to wild type mice suggests that mannose-binding lectin may be a therapeutic target following traumatic brain injury. Here, we evaluated the effects of a multivalent glycomimetic mannose-binding lectin ligand, Polyman9, following traumatic brain injury in mice. In vitro surface plasmon resonance assay indicated that Polyman9 dose-dependently inhibits the binding to immobilized mannose residues of plasma mannose-binding lectin-C selectively over that of mannose-binding lectin-A. Male C57Bl/6 mice underwent sham/controlled cortical impact traumatic brain injury and intravenous treatment with Polyman9/saline. Ex-vivo surface plasmon resonance studies confirmed that Polyman9 effectively reduces the binding of plasma mannose-binding lectin-C to immobilized mannose residues. In vivo studies up to four weeks post injury, showed that Polyman9 induces significant improvement in sensorimotor deficits (by neuroscore and beam walk), promotes neurogenesis (73% increase in doublecortin immunoreactivity), and astrogliosis (28% increase in glial fibrillary acid protein). Polyman9 administration in brain-injured mannose-binding lectin−/− mice had no effect on post-traumatic brain-injured functional deficits, suggestive of the specificity of its neuroprotective effects. The neurobehavioral efficacy of Polyman9 implicates mannose-binding lectin-C as a novel therapeutic target for traumatic brain injury.
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Li, Xing Jian, Shan Shan Gong i Qi Sun. "A Novel H-Phosphonate Method for the Synthesis of D-Mannose-1-Phosphate". Applied Mechanics and Materials 483 (grudzień 2013): 88–91. http://dx.doi.org/10.4028/www.scientific.net/amm.483.88.
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A novel and efficient method for the preparation of α-D-mannose-1-phosphate has been developed. Phosphitylation of tetraacetylated D-mannose, hydrolysis yielded H-phosphonate monoester. Silylation of H-phosphonate, followed by oxidative coupling and hydrolysis gave protected D-mannose-1-phosphate. Finally, deprotection of tetraacetylated D-mannose-1-phosphate afforded D-mannose-1-phosphate in excellent yield.
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Taguchi, T., E. Yamashita, T. Mizutani, H. Nakajima, M. Yabuuchi, N. Asano i I. Miwa. "Hepatic glycogen breakdown is implicated in the maintenance of plasma mannose concentration". American Journal of Physiology-Endocrinology and Metabolism 288, nr 3 (marzec 2005): E534—E540. http://dx.doi.org/10.1152/ajpendo.00451.2004.
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d-Mannose is an essential monosaccharide constituent of glycoproteins and glycolipids. However, it is unknown how plasma mannose is supplied. The aim of this study was to explore the source of plasma mannose. Oral administration of glucose resulted in a significant decrease of plasma mannose concentration after 20 min in fasted normal rats. However, in fasted type 2 diabetes model rats, plasma mannose concentrations that were higher compared with normal rats did not change after the administration of glucose. When insulin was administered intravenously to fed rats, it took longer for plasma mannose concentrations to decrease significantly in diabetic rats than in normal rats (20 and 5 min, respectively). Intravenous administration of epinephrine to fed normal rats increased the plasma mannose concentration, but this effect was negated by fasting or by administration of a glycogen phosphorylase inhibitor. Epinephrine increased mannose output from the perfused liver of fed rats, but this effect was negated in the presence of a glucose-6-phosphatase inhibitor. Epinephrine also increased the hepatic levels of hexose 6-phosphates, including mannose 6-phosphate. When either lactate alone or lactate plus alanine were administered as gluconeogenic substrates to fasted rats, the concentration of plasma mannose did not increase. When lactate was used to perfuse the liver of fasted rats, a decrease, rather than an increase, in mannose output was observed. These findings indicate that hepatic glycogen is a source of plasma mannose.
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Mildvan, A. S., Z. Xia, H. F. Azurmendi, P. M. Legler, M. R. Balfour, L. L. Lairson, S. G. Withers, S. B. Gabelli, M. A. Bianchet i L. M. Amzel. "Hydrogen bonding in the mechanism of GDP-mannose mannosyl hydrolase". Journal of Molecular Structure 790, nr 1-3 (czerwiec 2006): 160–67. http://dx.doi.org/10.1016/j.molstruc.2005.09.024.
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Liu, Deng-Rui, Quan-Lin Guan, Ming-Tai Gao, Lei Jiang i Hong-Xia Kang. "Mannose Receptor as a Potential Biomarker for Gastric Cancer: A Pilot Study". International Journal of Biological Markers 32, nr 3 (lipiec 2017): 278–83. http://dx.doi.org/10.5301/jbm.5000244.
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Background The mannose receptor is an immune adhesion molecule mainly expressed on the surface of antigen-presenting cells such as nonmature dendritic cells and macrophages. This study aimed to investigate mannose receptor expression and its predictive role in papillary gastric cancer patients. Methods The expression of the mannose receptor was measured in 120 samples of gastric cancer tissues and corresponding paracarcinoma tissues, by immunohistochemical and quantitative real-time PCR analysis. The relationships between mannose receptor expression and clinicopathological features of gastric cancer patients were analyzed. Results The expression rate of the mannose receptor in gastric cancer cells was 45.8% (54/120), significantly higher than that in the paracarcinoma tissue (20.0%, 36/120) (χ2 = 6.286, p = 0.012). High expression of the mannose receptor was closely related to tumor size, T stage, N stage and Union for International Cancer Control (UICC) stage of gastric cancer (p<0.05). A Kaplan-Meier survival model indicated that the survival of patients in the high-expression mannose receptor group was significantly shorter than in the low-expression mannose receptor group (p<0.05). Cox regression analysis showed that high mannose receptor expression was an independent predictor for the prognosis of patients with gastric cancer. Conclusions High mannose receptor expression indicates poor prognosis for gastric cancer patients. The mannose receptor may be an important molecular marker for gastric cancer prognosis.
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Belfrage, Emma, Camilla L. Jinnestål, Andreas Jönsen, Anders Bengtsson, Anna Åkesson, Artur Schmidtchen i Andreas Sonesson. "Role of Mannose-binding Lectin and Association with Microbial Sensitization in a Cohort of Patients with Atopic Dermatitis". Acta Dermato-Venereologica 103 (30.03.2023): adv2405. http://dx.doi.org/10.2340/actadv.v103.2405.
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Atopic dermatitis is a relapsing inflammatory skin condition, in which bacteria, fungi and viruses may colonize the skin and aggravate the condition. Mannose-binding lectin is part of the innate immune system. Polymorphism in the mannose-binding lectin gene can result in deficiency of mannose-binding lectin, which may affect defence against microbes. The aim of this study was to investigate whether polymorphisms in the mannose-binding lectin gene affect the extent of sensitization to common skin microbes, the skin barrier function, or the severity of the disease in a cohort of patients with atopic dermatitis. Genetic testing of mannose-binding lectin polymorphism was performed in 60 patients with atopic dermatitis. The disease severity, skin barrier function, and serum levels of specific immunoglobulin E against skin microbes were measured. In patients with low mannose-binding lectin genotype (group 1) 6 of 8 (75%) were sensitized to Candida albicans, compared to 14 of 22 (63.6%) patients with intermediate mannose-binding genotype (group 2) and 10 of 30 (33.3%) patients with high mannose-binding genotype (group 3). Group 1 (low mannose-binding lectin) was more likely to be sensitized to Candida albicans compared with group 3 (high mannose-binding lectin) (odds ratio 6.34, p-value 0.045). In this cohort of patients with atopic dermatitis, mannose-binding lectin deficiency was associated with increased sensitization to Candida albicans.
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Magnusson, S., i T. Berg. "Extremely rapid endocytosis mediated by the mannose receptor of sinusoidal endothelial rat liver cells". Biochemical Journal 257, nr 3 (1.02.1989): 651–56. http://dx.doi.org/10.1042/bj2570651.
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Isolated sinusoidal endothelial rat liver cells (EC) in suspension bound and internalized ovalbumin, a mannose-terminated glycoprotein, in a saturable manner. The binding and uptake were Ca2+-dependent and were effectively inhibited by alpha-methyl mannoside and yeast mannan, but not by galactose or asialoglycoproteins. This corresponds to the binding specificity described for the mannose receptor of macrophages and non-parenchymal liver cells. Binding studies indicated a surface pool of 20,000-25,000 mannose receptors per cell, with a dissociation constant of 6 x 10(-8) M. Uptake and degradation of ovalbumin by isolated EC were inhibited by weak bases and ionophores which inhibit acidification of endocytic vesicles and dissociation of receptor-ligand complexes. Cycloheximide had no effect on uptake or degradation. Degradation, but not uptake, was inhibited by leupeptin. We conclude that ovalbumin dissociates from the mannose receptors in the endosomal compartment and the receptors are recycled to the cell surface, while the ovalbumin is directed to the lysosomes for degradation. A fraction of the internalized ovalbumin was recycled intact to the cell surface and escaped degradation (retroendocytosis). The rate of internalization of ovalbumin by isolated EC was very fast, with a Ke (endocytotic rate constant) of 4.12 min-1, which corresponds to a half-life of 10 s for the surface pool of receptor-ligand complexes. To our knowledge, this is the highest Ke reported for a receptor-mediated endocytosis system.
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Liu, Z. H., G. E. Striker, M. Stetler-Stevenson, P. Fukushima, A. Patel i L. J. Striker. "TNF-alpha and IL-1 alpha induce mannose receptors and apoptosis in glomerular mesangial but not endothelial cells". American Journal of Physiology-Cell Physiology 270, nr 6 (1.06.1996): C1595—C1601. http://dx.doi.org/10.1152/ajpcell.1996.270.6.c1595.
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The macrophage mannose receptor, a carbohydrate-binding membrane protein, mediates endocytosis and phagocytosis. This study was undertaken to determine whether mannose receptors were expressed in resting glomerular mesangial and endothelial cells and whether their level was affected by cytokines. Neither mannose receptor mRNA nor proteins were found in resting mesangial or endothelial cells. Mannose receptor mRNA was induced in a dose- and time-dependent manner in mesangial cells by interleukin-1 alpha (IL-1 alpha) or tumor necrosis factor-alpha (TNF-alpha) but not by platelet-derived growth factor-B or IL-6. Cell surface receptors were found by fluorescence-activated cell sorter analysis. Binding to stimulated mesangial cells was saturable and inhibited by excess mannose-bovine serum albumin (BSA) but not by galactose-BSA. TNF-alpha and IL-1 alpha also induced apoptosis in mesangial cells. Mannose receptor expression was not restricted to apoptotic stimulated mesangial cells. Neither agonist induced mannose receptor expression or apoptosis in endothelial cells. Because immunoglobulin A, M, and G contain mannose residues, immune aggregates may be removed from the mesangium through cytokine-induced mannose receptors.
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BONNIN, Estelle, Michel LESSIRE, Nathaële WACRENIER i Fabien ALLEMAN. "Les polymères de mannose en production animale. 2. Les enzymes de dégradation des mannanes dans l’alimentation des porcs et des volailles". INRAE Productions Animales 33, nr 4 (6.04.2021): 295–306. http://dx.doi.org/10.20870/productions-animales.2020.33.4.4634.
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Les enzymes capables de dégrader les mannanes appartiennent à plusieurs familles d’hydrolases qui se distinguent par les sites de coupure sur ces polysaccharides. La plus connue est de loin la « β-mannanase », seule autorisée en alimentation animale en Europe et qui est spécifique des liaisons β-(1,4) entre deux mannoses. Si on ne se limite pas aux seules enzymes aujourd’hui homologuées pour l’alimentation animale, les mannosidases, les β-glucosidases, les α-galactosidases, et les mannane acétyl-estérases peuvent participer, seules ou en association, à l’hydrolyse des polymères de mannose. L’ajout d’une β-mannanase dans les aliments des volailles et des porcs permet de réduire en grande partie les effets antinutritionnels, en particulier inflammatoires, des β-mannanes. L’épargne de nutriments qui en résulte peut alors être directement valorisée en formulation en déconcentrant l’énergie du régime. Au-delà de l’économie réalisée sur le coût de l’aliment, des améliorations de la performance (indice de consommation en particulier) et de la santé digestive sont très souvent observées.
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Turner, M. W. "Mannose binding protein". Biochemical Society Transactions 22, nr 1 (1.02.1994): 88–94. http://dx.doi.org/10.1042/bst0220088.
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ARCHIVIST. "Mannose binding lectin". Archives of Disease in Childhood 85, nr 3 (1.09.2001): 201. http://dx.doi.org/10.1136/adc.85.3.201.
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Soothill, JF. "Mannose-binding lectin". Lancet 359, nr 9300 (styczeń 2002): 82. http://dx.doi.org/10.1016/s0140-6736(02)07305-1.
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Jensenius, Jens C. "Mannose-binding lectin". Lancet 359, nr 9300 (styczeń 2002): 82–83. http://dx.doi.org/10.1016/s0140-6736(02)07306-3.
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Martinez-Pomares, Luisa. "The mannose receptor". Journal of Leukocyte Biology 92, nr 6 (grudzień 2012): 1177–86. http://dx.doi.org/10.1189/jlb.0512231.
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Lennartz, M. R., T. E. Wileman i P. D. Stahl. "Isolation and characterization of a mannose-specific endocytosis receptor from rabbit alveolar macrophages". Biochemical Journal 245, nr 3 (1.08.1987): 705–11. http://dx.doi.org/10.1042/bj2450705.
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Rabbit alveolar macrophages express a plasma-membrane receptor that recognizes glycoprotein ligands bearing terminal mannose, fucose or N-acetylglucosamine residues. Macrophage membranes were washed extensively with buffers containing high salt and mannose or EDTA to remove endogenously bound ligand, before Triton X-100 extraction. The extracts were chromatographed on mannose-Sepharose. Elution with mannose, followed by dialysis and a second mannose-Sepharose step with EDTA elution, produced a preparation that migrated as single protein band of Mr 175,000 on SDS/polyacrylamide-gel electrophoresis. The purified protein binds mannose-BSA (bovine serum albumin) with a dissociation constant of 1.9 × 10(-8) M. Ligand binding is Ca2+ and pH-dependent, with maximal binding at neutral pH and low binding below pH 6.0. The binding of 125I-mannose-BSA is inhibited by ligands bearing high-mannose oligosaccharides, such as mannan or beta-glucuronidase, as well as the monosaccharides mannose, fucose and N-acetylglucosamine. Galactose, galactosylated BSA, glucose and mannose 6-phosphate are non-inhibitory. Amino acid compositional analyses indicate that the receptor contains high concentrations of aspartate/asparagine and glutamate/glutamine, and low amounts of methionine. The carbohydrate composition was studied by lectin overlays of electrophoretically transferred receptor, and the results indicate the presence of N-linked complex and O-linked sialylated oligosaccharides. A protein of Mr 175,000 was immunoprecipitated from radio-iodinated macrophage membranes with an antibody generated against purified rabbit lung mannose receptor.
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Chan, A. Y., C. S. Ho, T. Y. Chan i R. Swaminathan. "D-Mannose as a Preservative of Glucose in Blood Samples". Clinical Chemistry 38, nr 3 (1.03.1992): 411–13. http://dx.doi.org/10.1093/clinchem/38.3.411.
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Abstract We studied the changes in blood glucose concentration in blood samples collected in heparinized specimen tubes containing no other preservative, or containing NaF, D-mannose, or a combination of NaF and D-mannose. Blood concentration in samples taken into NaF decreased by 0.40 mmol/L in the first 2 h; thereafter, there was no change. In samples collected into mannose there was a small but significant decrease in blood glucose concentration with time. When samples containing mannose were analyzed immediately after collection, the concentration of glucose was higher than in later analyses, probably because of an exchange of intracellular glucose for extracellular mannose. When a combination of NaF and mannose was used, the blood glucose concentration was relatively stable but slightly higher than nonpreserved samples for the next 24 h. However, samples containing mannose were unsuitable for electrolyte analysis. We conclude that a combination of D-mannose and NaF may be a better preservative for blood glucose than either compound alone.
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Boschi, Alessandra, Micòl Pasquali, Claudio Trapella, Alessandro Massi, Petra Martini, Adriano Duatti, Remo Guerrini i in. "Design and Synthesis of 99mTcN-Labeled Dextran-Mannose Derivatives for Sentinel Lymph Node Detection". Pharmaceuticals 11, nr 3 (16.07.2018): 70. http://dx.doi.org/10.3390/ph11030070.
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Background: New approaches based on the receptor-targeted molecular interaction have been recently developed with the aim to investigate specific probes for sentinel lymph nodes. In particular, the mannose receptors expressed by lymph node macrophages became an attractive target and different multifunctional mannose derivate ligands for the labeling with 99mTc have been developed. In this study, we report the synthesis of a specific class of dextran-based, macromolecular, multifunctional ligands specially designed for labeling with the highly stable [99mTc≡N]2+ core. Methods: The ligands have been obtained by appending to a macromolecular dextran scaffold pendant arms bearing a chelating moiety for the metallic group and a mannosyl residue for allowing the interaction of the resulting macromolecular 99mTc conjugate with specific receptors on the external membrane of macrophages. Two different chelating systems have been selected, S-methyl dithiocarbazate [H2N‒NH‒C(=S)SCH3=HDTCZ] and a sequence of two cysteine residues, that in combination with a monophosphine coligand, are able to bind the [99mTc≡N]2+ core. Conclusions: High-specific-activity labeling has been obtained by simple mixing and heating of the [99mTc≡N]2+ group with the new mannose-dextran derivatives.
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Barrett-Bergshoeff, Marrie, Femke Noorman, Rogier Bos i Dingeman C. Rijken. "Monoclonal Antibodies against the Human Mannose Receptor that Inhibit the Binding of Tissue-type Plasminogen Activator". Thrombosis and Haemostasis 77, nr 04 (1997): 718–24. http://dx.doi.org/10.1055/s-0038-1656040.
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SummaryTo study the role of the mannose receptor in cellular uptake and degradation of tissue-type plasminogen activator (t-PA), a set of five monoclonal antibodies (Moab) was generated against the mannose receptor isolated from human placental tissue.All Moab specifically recognised the 175 kDa mannose receptor in a crude placenta extract, as shown in Western blot analysis. By use of im- munohistochemistry, we showed that in human placenta only the Hof- bauer cells (fetal macrophages) express the mannose receptor. Epitope competition experiments indicated that the Moab bound to at least two different epitopes on the receptor molecule. Moab 14-3, 14-5, and 15-2, which are directed against one of these epitopes, strongly inhibited the interaction between the purified mannose receptor and t-PA. These Moab also inhibited mannose receptor-mediated degradation of t-PA by cultured human macrophages. The low density lipoprotein receptor-related protein (LRP) mediated t-PA degradation was not affected by the Moab.It is concluded that the Moab are useful for studying the expression of the human mannose receptor in Western blot and in immunohisto-chemistry, and for studying the interactions between the human mannose receptor and the mannose-containing ligand t-PA.
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Fukuda, Ichiki, Shinichi Mochizuki i Kazuo Sakurai. "Macrophage-Targeting Gene Delivery Using a Micelle Composed of Mannose-Modified Lipid with Triazole Ring and Dioleoyl Trimethylammonium Propane". BioMed Research International 2015 (2015): 1–8. http://dx.doi.org/10.1155/2015/350580.
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Gene carriers with cell specific ligand molecules are needed for the treatment of several diseases. Mannose is known to be recognized and incorporated into the cells through mannose recognition lectins that are exclusively expressed on macrophages. In this study, we synthesized two types of mannose-modified lipids with different stereoisomer (α-mannose andβ-mannose). To make a complex with plasmid DNA (pDNA), termed “lipoplex,” we prepared a two-component micelle made from cationic lipid; dioleoyltrimethylammoniumpropane (DOTAP); and mannose-modified lipid (D/α-Man or D/β-Man). The prepared D/α-Man lipoplexes were able to bind to one of theα-mannose lectins concanavalin A (ConA) immobilized on gold substrate in the quartz-crystal microbalance sensor cell. D/β-Man lipoplexes did not show any frequency changes. These results indicate that the mannose residues were exposed on the lipoplexes, leading to not only the binding to ConA but also the prevention of nonspecific interactions with proteins. Both lipoplexes showed high transfection efficiencies to RAW264.7 cells which have several kinds of mannose lectins. This delivery system to macrophages may overcome the problems for gene therapy and may be used for the treatment of immune diseases involved in macrophages.
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Nagarajan, Kandasamy, Parul Grover, Roma Ghai, Ayushi Teharia, Sanjeev Chauhan i Jagannath Sahoo. "In vitro antioxidant potency of some smaller chain glycopeptides with the prediction of IC50 values". International Journal of Pharmacology and Toxicology 4, nr 2 (19.07.2016): 127. http://dx.doi.org/10.14419/ijpt.v4i2.6298.
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Hydrogen peroxide, 1,1-Diphenyl-2-picryl-hydrazyl (DPPH) and Phosphomolybdenum in-vitro assay was employed to determine the antioxidant potency of glycopeptides RN Mannose, RK starch, RNRN Mannose and RHRCR Starch using ascorbic acid as the standard drug. The percentage scavenging activity of the glycopeptides were determined at different concentrations and the IC50 value of the test compounds were subsequently compared with that of ascorbic acid. RN Mannose was found to be most potent antioxidant compound. Also, Swiss dock study was performed with three glycopeptides, viz., RHRCR Mannose, RN Mannose and RNRN Mannose.Among these, RHRCR Mannose was found to have the best affinity for the receptor with stearic energy -0.2306kcal/mol.
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Tian, Dandan, Yu Qiao, Qing Peng, Yuwei Zhang, Yuxin Gong, Linbo Shi, Xiaoyan Xiong, Mengxin He, Xiaoqing Xu i Bo Shi. "A Poly-D-Mannose Synthesized by a One-Pot Method Exhibits Anti-Biofilm, Antioxidant, and Anti-Inflammatory Properties In Vitro". Antioxidants 12, nr 8 (8.08.2023): 1579. http://dx.doi.org/10.3390/antiox12081579.
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In this study, D-mannose was used to synthesize poly-D-mannose using a one-pot method. The molecular weight, degree of branching, monosaccharide composition, total sugar content, and infrared spectrum were determined. In addition, we evaluated the safety and bioactivity of poly-D-mannose including anti-pathogen biofilm, antioxidant, and anti-inflammatory activity. The results showed that poly-D-mannose was a mixture of four components with different molecular weights. The molecular weight of the first three components was larger than 410,000 Da, and that of the fourth was 3884 Da. The branching degree of poly-D-mannose was 0.53. The total sugar content was 97.70%, and the monosaccharide was composed only of mannose. The infrared spectra showed that poly-D-mannose possessed characteristic groups of polysaccharides. Poly-D-mannose showed no cytotoxicity or hemolytic activity at the concentration range from 0.125 mg/mL to 8 mg/mL. In addition, poly-D-mannose had the best inhibition effect on Salmonella typhimurium at the concentration of 2 mg/mL (68.0% ± 3.9%). The inhibition effect on Escherichia coli O157:H7 was not obvious, and the biofilm was reduced by 37.6% ± 2.9% at 2 mg/mL. For Staphylococcus aureus and Bacillus cereus, poly-D-mannose had no effect on biofilms at low concentration; however, 2 mg/mL of poly-D-mannose showed inhibition rates of 33.7% ± 6.4% and 47.5% ± 4%, respectively. Poly-D-mannose showed different scavenging ability on free radicals. It showed the best scavenging effect on DPPH, with the highest scavenging rate of 74.0% ± 2.8%, followed by hydroxyl radicals, with the scavenging rate of 36.5% ± 1.6%; the scavenging rates of superoxide anion radicals and ABTS radicals were the lowest, at only 10.1% ± 2.1% and 16.3% ± 0.9%, respectively. In lipopolysaccharide (LPS)-stimulated macrophages, poly-D-mannose decreased the secretion of nitric oxide (NO) and reactive oxygen species (ROS), and down-regulated the expression of tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6). Therefore, it can be concluded that poly-D-mannose prepared in this research is safe and has certain biological activity. Meanwhile, it provides a new idea for the development of novel prebiotics for food and feed industries or active ingredients used for pharmaceutical production in the future.