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Quinn, Gary, James C. Wood, David J. J. Ryan, Kristen M. Suling, Kathleen M. Moran, Donna L. Kolber-Simonds, Julia L. Greenstein, Henk-Jan Schuurman, Robert J. Hawley y Clive Patience. "Porcine Endogenous Retrovirus Transmission Characteristics of Galactose α1-3 Galactose-Deficient Pig Cells". Journal of Virology 78, n.º 11 (1 de junio de 2004): 5805–11. http://dx.doi.org/10.1128/jvi.78.11.5805-5811.2004.
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ABSTRACT Galactose α1-3 galactose (Gal) trisaccharides are present on the surface of wild-type pig cells, as well as on viruses particles produced from such cells. The recognition of Gal sugars by natural anti-Gal antibodies (NAb) in human and Old World primate serum can cause the lysis of the particles via complement-dependent mechanisms and has therefore been proposed as an important antiviral mechanism. Recently, pigs have been generated that possess disrupted galactosyl-transferase (GGTA1) genes. The cells of these pigs do not express Gal sugars on their surface, i.e., are Gal null. Concerns have been raised that the risk of virus transmission from such pigs may be increased due to the absence of the Gal sugars. We investigated the sensitivity of porcine endogenous retrovirus (PERV) produced from Gal-null and Gal-positive pig cells to inactivation by purified NAb and human serum. PERV produced in Gal-null pig cells was resistant to inactivation by either NAb or human serum. In contrast, although Gal-positive PERV particles were sensitive to inactivation by NAb and human serum, they required markedly higher concentrations of NAb for inactivation compared to the Gal-positive cells from which they were produced. Complete inactivation of Gal-positive PERV particles was not achievable despite the use of high levels of NAb, indicating that NAb-mediated inactivation of cell-free PERV particles is an inefficient process.
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Gabrielli, Armando, Pietro Leoni, Giovanni Danieli, Konrad Herrmann, Thomas Krieg y Jorgen Wieslander. "Antibodies against galactosyl (α1→3) galactose in connective tissue diseases". Arthritis & Rheumatism 34, n.º 3 (marzo de 1991): 375–76. http://dx.doi.org/10.1002/art.1780340321.
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Hung, Le Dinh y Le Thi Doan Thuc. "High-mannose type N-glycan binding specificity of a novel lectin from the red alga (Betaphycus gelatinus)". Vietnam Journal of Biotechnology 17, n.º 4 (2 de noviembre de 2020): 709–18. http://dx.doi.org/10.15625/1811-4989/17/4/13697.
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The red alga, Betaphycus gelatinus is one of carrageenan sources in the world. The lectin from the red alga B. gelatinus was isolated by a combination of aqueous ethanol extraction, ethanol precipitation, ion-exchange chromatography and gel filtration chromatography and was designated as BGL after the specific name of alga. Lectin gave a single band with molecular mass of about 19,000 Da in both non-reducing and reducing SDS-PAGE conditions, therefore lectin exists in monomer form. The hemagglutination activities of BGL were stable over a wide range of pH from 3 to 10, temperature up 60 oC and not affected by either the presence of EDTA or addition of divalent cations, indicating that lectin requires no metal for biological activity. The hemagglutination activities of BGL were not inhibited by monosaccharides and glycoproteins, D-glucose, D-mannose, D-galactose, D-xylose, N-acetyl-galactosamine, N-acetyl-glucosamine, N-acetyl-neuraminic acid, N-acety-D-mannosamine, transferrin and fetuin, but strongly inhibited by glycoproteins bearing high-mannose type N-glycan, such as yeast mannan and porcine thyroglobulin. Lectin BGL is specific for N-glycans and may recognize terminal (α1–3) or (α1–6)-linked mannose residues in structure Man(α1-6)[Man(α1-3)]Man(α1-6)[Man(α1-3)]Man(β1-4)GlcNAc(β1-4)GlcNAc of N-glycans. High-mannose type N-glycan binding specificities of this lectin highly resemble with those of the anti-cancer, anti-virus and anti-bacteria lectins from the red algae, carrageenophytes, including Eucheuma serra (ESA-2), Eucheuma denticulatum (EDA-2), Kappaphycus striatum (KSA-2), Kappaphycus alvarezii (KAA-1 and KAA-2) and Solieria filiformis (SfL1 and SfL2). The red alga B. gelatinus could promise to be a good source of valuable lectins for application in biochemistry and biomedicine.
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Manez, R., I. Diaz, A. Centeno, E. Gonzalez, M. Hermida, F. Blanco, H. Ff Davies y A. Katopodis. "Sustained decrease of serum anti-galactose α1–3-galactose antibodies in baboons by removing aerobic gram-negative bacteria from the bowel". Transplantation Proceedings 31, n.º 1-2 (febrero de 1999): 947–48. http://dx.doi.org/10.1016/s0041-1345(98)01849-1.
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LAUDER, M. Robert, N. Thomas HUCKERBY, A. Ian NIEDUSZYNSKI y H. K. Anna PLAAS. "Age-related changes in the structure of the keratan sulphate chains attached to fibromodulin isolated from articular cartilage". Biochemical Journal 330, n.º 2 (1 de marzo de 1998): 753–57. http://dx.doi.org/10.1042/bj3300753.
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Bovine articular cartilage fibromodulin has been isolated from animals aged 3 months to 8 years, and the attached keratan sulphate (KS) chains digested with keratanase II. The oligosaccharides generated have been reduced, examined by high-pH anion-exchange chromatography and their structures identified by comparison with standards. It has been shown that in fibromodulin from young articular cartilage, the KS chains do not possess either non-reducing terminal (α2-6)-linked N-acetylneuraminic acid or fucose (α1-3)-linked to sulphated N-acetylglucosamine residues. However, an age-related increase has been observed in the abundance of both (α2-6)-linked N-acetylneuraminic acid and (α1-3)-linked fucose, neither of which is found in KS isolated from non-articular cartilage, irrespective of the age of the source. Interestingly, the KS chain length remains constant as a function of age, which possibly relates to a role in collagen fibril assembly. In addition, no significant age-related changes were identified in levels of galactose sulphation.
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Li, Jun, Hui-Chen Hsu, Ping-Ar Yang, Qi Wu y John Mountz. "Fucosylation regulates cell death in rheumatoid arthritis (87.24)". Journal of Immunology 184, n.º 1_Supplement (1 de abril de 2010): 87.24. http://dx.doi.org/10.4049/jimmunol.184.supp.87.24.
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Abstract Abnormal inflammation and apoptosis are major pathogenic features of synovial fibroblasts (SF) in rheumatoid arthritis (RA). Fucosylation, an important type of glycosylation, has been identified in cancer and inflammation conditions. The role of fucosylation in RA was investigated. Real-time PCR indicated that between RASF and osteoarthritis (OA) SF (N=14 each), there was no difference in the expression of apoptosis related molecules, including tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), its receptors DR4, DR5, DR6, DcR1, DcR2, and regulators of apoptosis FLIPL and cIAPs. However, there was a higher level of α1-2-Fucosyltransferase (Fut1, P=0.016), α1-3/1-4-Fucosyltransferase (Fut3, P=0.018) and α1-3-Fucosyltransferase (Fut6, P=0.038), but not α1-6-Fucosyltransferase (Fut8, P=0.910) in RA compared to OA synovial tissues. Interestingly, a strong positive correlation between TNFα and Fut1, Fut3 and Fut6 was identified. Fut1 also correlated with Il17a. Preincubation of RASFs with 2-Deoxy-D-Galactose (15 mM/ml), a FUT1 inhibitor, decreased the sensitivity to TRA-8, an anti-human DR5 antibody, mediated apoptosis and this effect can be reversed by fucose (15 mM). Similar results were also found on human monocyte/macrophage cell lines, HL60 and THP-1. Our studies suggest that fucosylation is strongly associated with abnormal inflammation and apoptosis in RA effector cells. Fucosylation might be a novel target for RA therapy.
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Lee, Chan Hyoung, Hee Taek Kim, Eun Ju Yun, Ah Reum Lee, Sa Rang Kim, Jae-Han Kim, In-Geol Choi y Kyoung Heon Kim. "A Novel Agarolytic β-Galactosidase Acts on Agarooligosaccharides for Complete Hydrolysis of Agarose into Monomers". Applied and Environmental Microbiology 80, n.º 19 (18 de julio de 2014): 5965–73. http://dx.doi.org/10.1128/aem.01577-14.
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ABSTRACTMarine red macroalgae have emerged to be renewable biomass for the production of chemicals and biofuels, because carbohydrates that form the major component of red macroalgae can be hydrolyzed into fermentable sugars. The main carbohydrate in red algae is agarose, and it is composed ofd-galactose and 3,6-anhydro-l-galactose (AHG), which are alternately bonded by β1-4 and α1-3 linkages. In this study, a novel β-galactosidase that can act on agarooligosaccharides (AOSs) to release galactose was discovered in a marine bacterium (Vibriosp. strain EJY3); the enzyme is annotated asVibriosp. EJY3 agarolytic β-galactosidase (VejABG). Unlike thelacZ-encoded β-galactosidase fromEscherichia coli,VejABG does not hydrolyze common substrates like lactose and can act only on the galactose moiety at the nonreducing end of AOS. The optimum pH and temperature ofVejABG on an agarotriose substrate were 7 and 35°C, respectively. Its catalytic efficiency with agarotriose was also similar to that with agaropentaose or agaroheptaose. Since agarotriose lingers as the unreacted residual oligomer in the currently available saccharification system using β-agarases and acid prehydrolysis, the agarotriose-hydrolyzing capability of this novel β-galactosidase offers an enormous advantage in the saccharification of agarose or agar in red macroalgae for its use as a biomass feedstock for fermentable sugar production.
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Nakahashi, Hiromitsu, Tatsuya Oda, Osamu Shimomura, Yoshimasa Akashi, Kazuhiro Takahashi, Yoshihiro Miyazaki, Tomoaki Furuta et al. "Aberrant Glycosylation in Pancreatic Ductal Adenocarcinoma 3D Organoids Is Mediated by KRAS Mutations". Journal of Oncology 2024 (18 de marzo de 2024): 1–12. http://dx.doi.org/10.1155/2024/1529449.
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Aberrant glycosylation in tumor cells is a hallmark during carcinogenesis. KRAS gene mutations are the most well-known oncogenic abnormalities but their association with glycan alterations in pancreatic ductal adenocarcinoma (PDAC) is largely unknown. We employed patient-derived 3D organoids to culture pure live PDAC cells, excluding contamination by fibroblasts and immune cells, to gasp the comprehensive cancer cell surface glycan expression profile using lectin microarray and transcriptomic analyses. Surgical specimens from 24 PDAC patients were digested and embedded into a 3D culture system. Surface-bound glycans of 3D organoids were analyzed by high-density, 96-lectin microarrays. KRAS mutation status and expression of various glycosyltransferases were analyzed by RNA-seq. We successfully established 16 3D organoids: 14 PDAC, 1 intraductal papillary mucinous neoplasm (IPMN), and 1 normal pancreatic duct. KRAS was mutated in 13 (7 G12V, 5 G12D, 1 Q61L) and wild in 3 organoids (1 normal duct, 1 IPMN, 1 PDAC). Lectin reactivity of AAL (Aleuria aurantia) and AOL (Aspergillus oryzae) with binding activity to α1-3 fucose was higher in organoids with KRAS mutants than those with KRAS wild-type. FUT6 (α1-3fucosyltransferase 6) and FUT3 (α1-3/4 fucosyltransferase 3) expression was also higher in KRAS mutants than wild-type. Meanwhile, mannose-binding lectin (rRSL [Ralstonia solanacearum] and rBC2LA [Burkholderia cenocepacia]) signals were higher while those of galactose-binding lectins (rGal3C and rCGL2) were lower in the KRAS mutants. We demonstrated here that PDAC 3D-cultured organoids with KRAS mutations were dominantly covered in increased fucosylated glycans, pointing towards novel treatment targets and/or tumor markers.
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Hernàndez, Dimas E., Aaron Cohen, Denisse Fisher, Marı̀a Correnti y Ricardo Harner. "Antibody Levels against Galactosyl (α1 → 3) Galactose Epitopes in Cervical Mucus from Patients with Human Papillomavirus Infection". Gynecologic Oncology 84, n.º 3 (marzo de 2002): 374–77. http://dx.doi.org/10.1006/gyno.2001.6516.
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Seo, Ho Seong, Robert T. Cartee, David G. Pritchard y Moon H. Nahm. "A New Model of Pneumococcal Lipoteichoic Acid Structure Resolves Biochemical, Biosynthetic, and Serologic Inconsistencies of the Current Model". Journal of Bacteriology 190, n.º 7 (1 de febrero de 2008): 2379–87. http://dx.doi.org/10.1128/jb.01795-07.
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ABSTRACT Lipoteichoic acid (LTA) is an essential bacterial membrane polysaccharide (cell wall component) that is attached to the membrane via a lipid anchor. According to the currently accepted structure of pneumococcal LTA, the polysaccharide is comprised of several repeating units, each of which starts with glucose and ends with ribitol, with the lipid anchor predicted to be Glc(β1→3)AATGal(β1→3)Glc(α1→3)-acyl2Gro, where AATGal is 2-acetamido-4-amino-2,4,6-trideoxy-d-galactose. However, this lipid anchor has not been detected in pneumococcal membranes. Furthermore, the currently accepted structure does not explain the Forssman antigen properties of LTA and predicts a molecular weight for LTA that is larger than its actual observed molecular weight. To resolve these problems, we used mass spectrometry to analyze the structure of LTA isolated from several pneumococcal strains. Our study found that the R36A pneumococcal strain produces LTA that is more representative of pneumococci than that previously characterized from the R6 strain. Analysis of LTA fragments obtained after hydrofluoric acid and nitrous treatments showed that the fragments were consistent with an LTA nonreducing terminus consisting of GalNAc(α1→3)GalNAc(β1→, which is the minimal structure for the Forssman antigen. Based on these data, we propose a revised model of LTA structure: its polysaccharide repeating unit begins with GalNAc and ends with AATGal, and its lipid anchor is Glc(α1→3)-acyl2Gro, a common lipid anchor found in pneumococcal membranes. This new model accurately predicts the observed molecular weights. The revised model should facilitate investigation of the relationship between LTA's structure and its function.
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Dinh Hung, Le, Tran Thi Hai Yen y Dinh Thanh Trung. "Characterization of O-glycan binding lectin from the red alga Hydropuntia eucheumatoides". Vietnam Journal of Biotechnology 16, n.º 4 (8 de agosto de 2020): 687–96. http://dx.doi.org/10.15625/1811-4989/16/4/13056.
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The red alga, Hydropuntia eucheumatoides is one of the algal genera from which agar is commercially extracted, and is the main source of agar in the world. The lectin HEL from the red alga H. eucheumatoides was isolated by a combination of aqueous ethanol extraction, ethanol precipitation, ion exchange and filtration chromatography. Lectin gave a single band with molecular mass of 17,000 Da in both non-reducing and reducing SDS-PAGE conditions, therefore lectin exists in monomeric form. The hemagglutination activities of HEL were stable over a wide range of pH from 3 to 10, temperature up 60 oC and not affected by either the presence of EDTA or addition of divalent cations, indicating that lectin requires no metal for biological activity. The hemagglutination activities of HEL were not inhibited by monosaccharides and glycoproteins, D-glucose, D-mannose, D-galactose, D-xylose, N-acety-D-mannosamine, transferin, fetuin and yeast mannan, but strongly inhibited by monosaccharides containing acetamido groups at equatorial C2 position, such as N-acetyl-galactosamine, N-acetyl-glucosamine, N-acetyl-neuraminic acid and glycoprotein porcine stomach mucin bearing O-glycans. Thus, lectin is specific for O-glycans and may recognize the sequences GalNAcαSer/Thr, GalNAc(α1-3)[Fuc(α1-2)]Gal(β1-4)GlcNAc(β1-3)GalNAc- and GluNAc(α1-4)Gal- under interacting with the acetamido groups at equatorial C2 position of the terminal sugar residues in oligosaccharide structures of O-glycans. The red alga H. eucheumatoides could promise to be a source of valuable lectins for application in biochemistry and biomedicine.
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Klein, Reinhild, Rupert Timpl, Dietrich Plester, Fortunato R. Zanetti y Peter A. Berg. "High Antibody Levels against Mouse Laminin with Specificity for Galactosyl-(α1–3)Galactose in Patients with Inner Ear Diseases". Annals of Otology, Rhinology & Laryngology 98, n.º 7 (julio de 1989): 537–42. http://dx.doi.org/10.1177/000348948909800708.
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Sera of 413 patients with inner ear diseases were examined for ELISA binding to mouse laminin and compared to a normal group. Strongly enhanced antilaminin antibody reactions were observed in a large number of patients with sensorineural hearing loss (68%), tinnitus (60%), and sudden deafness (46%), but not in those with Meniere's disease (14%) or normal individuals (8%). Absorption experiments demonstrated that these antibodies are also responsible for the antisarcolemmal antibody pattern in the immunofluorescence test and for the reaction with pig kidney microsomes in the ELISA. Immunochemical studies showed that laminin binding of high or low titer in sera from patients and normal individuals is due to the Galα1-3Gal epitope present in N-linked oligosaccharides of mouse laminin. No reactions were observed with human laminin, which lacks this epitope. The findings suggest that high levels of antibodies against carbohydrate structures are triggered by persistent infections, providing some new insights about the possible cause of these diseases.
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Reynard, Olivier, Frédéric Jacquot, Gwénaëlle Evanno, Hoa Le Mai, Apolline Salama, Bernard Martinet, Odile Duvaux et al. "Anti-EBOV GP IgGs Lacking α1-3-Galactose and Neu5Gc Prolong Survival and Decrease Blood Viral Load in EBOV-Infected Guinea Pigs". PLOS ONE 11, n.º 6 (9 de junio de 2016): e0156775. http://dx.doi.org/10.1371/journal.pone.0156775.
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Shihab, Elaf M. y Haitham M. Kadhim. "The Impact of Carvedilol on Organ Index, Inflammatory Mediators, Oxidative Stress Parameters and Skin Markers in D-Galactose-Induced Aging Mice". INTERNATIONAL JOURNAL OF DRUG DELIVERY TECHNOLOGY 13, n.º 03 (25 de septiembre de 2023): 1017–23. http://dx.doi.org/10.25258/ijddt.13.3.41.
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Background: Aging processes are defined as those that increase the susceptibility of individuals, as they grow older, to the factors that eventually lead to death. It is a complex multi-factorial process where several factors may interact simultaneously and may operate at many levels of functional organization.. Accumulating evidence has suggested that active ingredients that possess antioxidative and anti-inflammatory proprties could decrease the incidence and development of aging-related diseases and promote longevity. Carvedilol is a non-selective third generation β-blocker/α1-blocker with antioxidant and inflammatory activity to evaluate its antiaging effect and to investigate if it is better to given carvedilol with aging induction or after aging induction is established. Aim: To evaluate the effect of carvedilol on organ index, inflammatory mediators, oxidative stress parameters and skin markers in d-galactose-induced aging mice. Method: Male (swiss albino mice) weighing 20 to 30 g and aged 3 to 6 months was randomly divided into six groups , each consisting of 10 animals (60 mice in total). Group I was given normal saline orally only for six weeks, group II was given d-galactose 500 mg/kg orally only for six weeks, group III was given d-galactose 500 mg/kg orally and vitamin C 100 mg/kg orally concomitantly for six weeks, group IV given d-galactose 500 mg/kg orally only for six weeks, then directly next day after ending of aging induction, vitamin c 100 mg/kg started for another six weeks, group V given d-galactose 500 mg/kg orally and carvedilol 10 mg/kg orally concomitantly for six weeks, group VI given d-galactose 500 mg/kg orally only for six weeks, then directly next day after ending of aging induction, carvedilol 10 mg/kg started for another six weeks. After that, animals were weighed, euthanized, and dissected, the heart was removed and the organ index was calculated. Also the heart tissue is divided in to two parts, one homogenated to measure interleukin-Iβ, tumor necrosis factor-alpha, glutathione peroxidase and malondialdehyde, while the other piece for histopathological analysis to determine the presence of hypertrophy. Skin tissue was taken and homogenated for ELISA assay (measurement of collagen I and III levels ). Results: Results showed a significant decrease in heart organ index in animals that received carvedilol orally administered compared to aged group, with a substantial decrease in inflammatory mediators, malondialdehyde level and a marked increase in glutathione peroxidase level, collagen I and collagen III levels. Furthermore, carvedilol reverses the myocardial hypertrophy induced by D-galactose. Conclusion: The present study suggests that carvedilol has a positive antiaging benefit in reducing oxidative stress, decreasing inflammatory and skin aging markers and improving hypertrophic cardiac cells. Regarding the timing of drug administration, although carvedilol shows a benficial continuing impact when given with and after the initiation of aging. It’s better to give at starting of the aging process to control the aging series as soon as possible
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COUTO, A., M. GONCALVES, W. COLLI y R. DELEDERKREMER. "The N-linked carbohydrate chain of the 85-kilodalton glycoprotein from Trypanosoma cruzi trypomastigotes contains sialyl, fucosyl and galactosyl (α1–3)galactose units". Molecular and Biochemical Parasitology 39, n.º 1 (febrero de 1990): 101–7. http://dx.doi.org/10.1016/0166-6851(90)90012-b.
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KARAIVANOVA, K. Velislava y G. Robert SPIRO. "Sulphation of N-linked oligosaccharides of vesicular stomatitis and influenza virus envelope glycoproteins: host cell specificity, subcellular localization and identification of substituted saccharides". Biochemical Journal 329, n.º 3 (1 de febrero de 1998): 511–18. http://dx.doi.org/10.1042/bj3290511.
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The presence of sulphate groups on various saccharide residues of N-linked carbohydrate units has now been observed in a number of glycoproteins. To explore the cell specificity of this post-translational modification, we evaluated sulphate incorporation into virus envelope glycoproteins by a variety of cells, since it is believed that assembly of their N-linked oligosaccharides is to a large extent dependent on the enzymic machinery of the host. Employing the vesicular stomatitis virus (VSV) envelope glycoprotein (G protein) as a model, we noted that the addition of [35S]sulphate substituents into its complex carbohydrate units occurred in Madin-Darby canine kidney (MDCK), Madin-Darby bovine kidney, LLC-PK1 and BHK-21 cell lines but was not detectable in BRL 3A, BW5147.3, Chinese hamster ovary, HepG2, NRK-49F, IEC-18, PtK1 or 3T3 cells. The sulphate groups were exclusively located on C-3 of galactose [Gal(3-SO4)] and/or C-6 of N-acetylglucosamine [GlcNAc(6-SO4)] residues in the N-acetyllactosamine sequence of the branch chains. Moreover, we observed that the pronounced host-cell-dependence of the terminal galactose sulphation was reflected by the 3ʹ-phosphoadenosine 5ʹ-phosphosulphate:Gal-3-O-sulphotransferase activity assayed in vitro. Comparative studies carried out on the haemagglutinin of the influenza virus envelope formed by MDCK and LLC-PK1 cells indicated that sulphate in this glycoprotein was confined to its complex N-linked oligosaccharides where it occurred as Gal(3-SO4) and GlcNAc(6-SO4) on peripheral chains as well as on the mannose-substituted N-acetylglucosamine of the core. Since sulphation in both internal and peripheral locations of the virus glycoproteins was found to be arrested by the α1 → 2 mannosidase inhibitor, kifunensine, as well as by the intracellular migration block imposed by brefeldin A, it was concluded that this modification is a late biosynthetic event which most likely takes place in the trans-Golgi network.
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ROBBE, Catherine, Calliope CAPON, Bernadette CODDEVILLE y Jean-Claude MICHALSKI. "Structural diversity and specific distribution of O-glycans in normal human mucins along the intestinal tract". Biochemical Journal 384, n.º 2 (23 de noviembre de 2004): 307–16. http://dx.doi.org/10.1042/bj20040605.
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Purified human mucins from different parts of the intestinal tract (ileum, cecum, transverse and sigmoid colon and rectum) were isolated from two individuals with blood group ALeb (A-Lewisb). After alkaline borohydride treatment the released oligosaccharides were structurally characterized by nano-ESI Q-TOF MS/MS (electrospray ionization quadrupole time-of-flight tandem MS) without prior fractionation or derivatization. More than 100 different oligosaccharides, with up to ten monosaccharide residues, were identified using this technique. Oligosaccharides based on core 3 structures, GlcNAc(β1-3)GalNAc (where GlcNAc is N-acetyl-D-glucosamine and GalNAc is N-acetylgalactosamine), were widely distributed in human intestinal mucins. Core 5 structures, GalNAc(α1-3)GalNAc, were also recovered in all fractions. Moreover, a comparison of the oligosaccharide repertoire, with respect to size, diversity and expression of glycans and terminal epitopes, showed a high level of mucin-specific glycosylation: highly fucosylated glycans, found specifically in the small intestine, were mainly based on core 4 structures, GlcNAc-(β1-3)[GlcNAc(β1-6)]GalNAc, whereas the sulpho-LeX determinant carrying core 2 glycans, Gal(β1-3)[GlcNAc(β1-6)]-GalNAc (where Gal is galactose), was recovered mainly in the distal colon. Blood group H and A antigenic determinants were present exclusively in the ileum and cecum, whereas blood group Sda/Cad related epitopes, GalNAc(β1-4)[NeuAc(α2-3)]Gal (where NeuAc is N-acetylneuraminate), were found to increase along the length of the colon. Our findings suggest that mucins create an enormous repertoire of potential binding sites for micro-organisms that could explain the regio-specific colonization of bacteria in the human intestinal tract.
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Rawley, Orla, Jamie O'Sullivan, Gudmundur Bergsson, Alain Chan, Rachel Therese McGrath, Maartje van den Biggelaar, Jan Voorberg, Vince Jenkins y James S. O'Donnell. "Specific N- and O-Linked Carbohydrate Structures Mediate Von Willebrand Factor Interaction with Galectins -1 and -3". Blood 118, n.º 21 (18 de noviembre de 2011): 2234. http://dx.doi.org/10.1182/blood.v118.21.2234.2234.
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Abstract Abstract 2234 Von Willebrand Factor (VWF) is extensively glycosylated with both N- and O-linked carbohydrates. Moreover, these complex glycan structures influence VWF functional properties, including susceptibility to ADAMTS13 proteolysis, and plasma clearance. The molecular mechanisms through which VWF glycosylation (including ABO blood group antigens) act to influence VWF physiology remains unexplained. However, recent data suggest that VWF circulates in normal plasma bound to various carbohydrate-binding proteins, including specific members of the galectin family. In addition, galectin-3 binding has been reported to influence VWF cleavage by ADAMTS13. In this context, we sought to elucidate the role of specific VWF glycan determinants in modulating galectin interaction. VWF was purified from human plasma (pdVWF) by cryoprecipitation and gel filtration. VWF glycosylation was then modified using exoglycosidases and quantified by specific lectin ELISAs. Blood group specific VWF was also purified from pooled group AB, O, or Bombay plasmas. Galectins-1 and -3 were transiently expressed in competent E-coli cells with an N-terminal histidine tag, and purified by nickel chromatography. Finally, binding interactions were characterized via modified immunosorbant assay. In keeping with the previous report of Lenting et al, human pdVWF bound to both galectin-1 and galectin-3 in a dose-dependent manner. Enzymatic desialylation of pdVWF with α2-3,6,8,9 neuraminidase (Neu-VWF) markedly enhanced binding to galectin-1 (231±6%, p<0.0001). Similarly, removal of terminal sialic acid also increased binding to galectin-3, albeit to a lesser extent (136±6%, p<0.05). To further define the role of VWF glycans in regulating galectin binding, pdVWF was exposed to sequential neuraminidase and galactosidase digestions to remove terminal sialic acid and sub-terminal galactose residues (NeuGal-VWF). In contrast to the enhanced binding of Neu-VWF, binding of NeuGal-VWF to both galectin -1 and -3 was significantly reduced (51±5% and 52±6% compared to pdVWF; p<0.005). Cumulatively these findings suggest that loss of capping sialic acid and exposure of sub-terminal galactose critically regulates VWF-galectin binding. Treatment with PNGase F to completely remove N-linked carbohydrate structures (PNG-VWF) markedly decreased binding to galectin -1 and -3 (13±1% and 57±2%, p<0.001). Moreover, combined PNGase F and O-glycosidase digestions further attenuated galectin-3 binding (21±1%, p<0.001), suggesting that both the N- and O-linked glycans are involved in mediating the VWF-galectin interaction. ABO(H) blood group antigens are expressed on both the N-linked and O-linked glycans of human VWF. Moreover, ABO(H) determinants influence VWF susceptibility to ADAMTS13 proteolysis and plasma VWF half-life, through unknown mechanisms. Purified VWF from normal group AB individuals bound to both galectin-1 and galectin-3 significantly better than group O VWF (146±8% and 483±19%; p<0.01). Conversely, no significant difference in binding was observed between Group O and Bombay VWF. Consequently, although terminal A (GalNAc) and B (Gal) sugar moieties promote galectin binding, expression of terminal α1–2 fucose residues is not important. The glycosylation profile of platelet-VWF differs from that of pdVWF. In particular, platelet-VWF expresses reduced levels of both capping sialic acid and sub-terminal galactose residues (∼50%), and lacks AB blood group antigens. To characterize the effects of this differential sugar expression on galectin binding, platelet-derived VWF was isolated and purified (platelet freeze-thawing followed by immuno-affinity chromatography with monoclonal CLB-Rag20). In keeping with the reduction in Gal and AB blood group antigen expression, platelet VWF bound less well to galectin-1 and galectin-3 (72±6% and 67±7% versus pdVWF; p<0.05). These novel data demonstrate that both the N- and O-linked oligosaccharide structures of VWF are involved in mediating galectin binding. In particular, expression of terminal AB blood group antigens, and expression of sub-terminal galactose moieties following loss of capping sialic acid, both markedly enhance galectin binding affinity. Further studies will be required to define how galectin binding is involved in mediating the functional consequences of variation in VWF glycans. Disclosures: No relevant conflicts of interest to declare.
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Perez-Aguilar, Sandra, David Torres-Tirado, Guadalupe Martell-Gallegos, Jimena Velarde-Salcedo, Ana Paulina Barba-de la Rosa, Maureen Knabb y Rafael Rubio. "G protein-coupled receptors mediate coronary flow- and agonist-induced responses via lectin-oligosaccharide interactions". American Journal of Physiology-Heart and Circulatory Physiology 306, n.º 5 (1 de marzo de 2014): H699—H708. http://dx.doi.org/10.1152/ajpheart.00481.2013.
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Blood flow acts parallel to the coronary luminal endothelial surface layer (LESL) and modulates multiple parenchymal functions via the release of paracrine agents. Evidence indicates that the LESL may be a flow-sensing organelle and that perhaps through flow-induced lectin (L)·oligosaccharide (O) complex formation (L·O) participates in this process. LESL integrins and selectins are both lectinic and flow sensitive, but the L properties of flow-sensitive G protein-coupled receptors (GPCRs) are unknown. Therefore, we investigated the presence of L in the LESL and hypothesized that if flow-sensitive GPCRs are L, flow and O will determine their response to receptor activation. The LESL protein fraction isolated from guinea pig hearts was passed through an affinity chromatography column made of three sugars, mannose, galactose, and N-acetylglucosamine, and the lectinic fraction was eluted. Immune dot blot was used to identify L proteins in the LESL fraction. Our results indicate the following. 1) Two-dimensional SDS-PAGE (2D-SDS-PAGE) of the LESL lectinic fraction revealed at least 167 Ls. 2) Among these Ls, we identified three selectins and the GPCRs: angiotensin II, bradykinin (B2-R), adenosine A1 and A2, prolactin, endothelin, α1-adrenergic (α1A-R), thromboxane A2, β1-adrenergic, β3-adrenergic, and insulin receptors; the first six GPCRs are known to be flow sensitive. 3) The amplitude of receptor-induced vascular responses by α1A-R and B2-R activation (phenylephrine or bradykinin, respectively) was a function of flow and O (hyaluronidate). Our results support a novel mechanism of GPCR-mediated responses to flow via L·O interaction.
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Sullivan, Jamie O', Orla Rawley, Vince Jenkins, Alain Chion, Teresa M. Brophy y James S. O'Donnell. "Identification Of Galectin-1 and Galectin-3 As Novel Binding Partners For Factor VIII". Blood 122, n.º 21 (15 de noviembre de 2013): 28. http://dx.doi.org/10.1182/blood.v122.21.28.28.
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Abstract During biosynthesis, Factor VIII (FVIII) undergoes complex post-translational modification including significant glycosylation. Consequently each FVIII molecule can contains 25 N- and 6 O-linked glycans. These carbohydrate structures are of physiological significance. For example, FVIII glycan expression modulates intracellular trafficking and also regulates FVIII clearance by dendritic cells. Nevertheless, the molecular mechanisms through which glycan structures influence FVIII biology remains poorly defined. Interestingly, carbohydrate-binding galectins (Gal) -1 and -3 have recently been reported to bind human VWF. Moreover, these galectin interactions significantly influence VWF function. In this study, based upon similar glycans expression profiles, we hypothesised that galectins might also constitute novel binding partners for human FVIII. In brief, His-tagged Gal-1 and Gal-3 were expressed in E-coli and purified using nickel chromatography. Recombinant FVIII (rFVIII) was purified from different commercial concentrates. Subsequently, FVIII glycosylation was modified using specific exoglycosidases and quantified by lectin-binding ELISA. Galectin-FVIII interaction was characterised using modified immunosorbant assays and surface plasmon resonance (SPR). In plate–binding assays using purified proteins and SPR studies, both Gal-1 and Gal-3 bound to full length rFVIII in a time- and dose-dependent manner. Interestingly the apparent affinities of the galectin-FVIII interactions (Kd of 0.11 ± 0.02nM for Gal-1 and 0.21 ± 0.1nM for Gal-3 respectively) were unusually high for these lectins. Digestion with PNGase F to remove N-linked glycans ablated FVIII binding to Gal-1 (8.6 ± 1%; p<0.0001). In contrast, PNG-FVIII retained significant ability to bind Gal-3 (30.3 ± 3%; p<0.0001). However, combined FVIII digestion with both PNGase F and O glycosidase further attenuated Gal-3 binding (16.5 ± 2%; p<0.05). Cumulatively these findings suggest that whilst Gal-1 binding is mediated predominantly through the N-linked glycans of FVIII, both N- and O-linked glycans modulate its interaction with Gal-3. The majority of FVIII glycans are contained within the B domain. Unsurprisingly, Gal-1 and Gal-3 binding were both markedly attenuated for B domain deleted rFVIII compared to full length rFVIII (42 ± 1% and 26 ± 0.8%; p<0.0001). Previous studies have described different glycosylation profiles for specific full length commercial rFVIII products. To investigate the relevance of this differential glycosylation, we compared the galectin-binding properties of Advate® (CHO cell line) and Helixate® (BHK cell line). Interestingly, Gal-1 and Gal-3 both displayed significantly enhanced affinity for Helixate (107 ± 2% and 124 ± 1%; p<0.05). These findings are consistent with the fact that the N-linked glycans of BHK-derived FVIII express galactose α1-3 galactose epitopes which constitute preferential galectin-binding ligands. To determine whether FVIII interacts with galectins in vivo, immunoprecipitation studies were performed using plasma from VWF-/- mice. We observed that that both Gal-1 and Gal-3 were co-precipitated with FVIII even in the absence of VWF. Consequently, both the VWF-FVIII complex and free FVIII in plasma are likely to circulate in a complex with galectins. Importantly, recent studies have reported a prothrombotic phenotype in Gal-1/Gal-3 double deficient mice compared to wild type controls following ferric chloride injury. To investigate whether galectin-binding influences FVIII function, FVIII activity was assessed using a one-stage clotting assay in the presence of increasing galectin concentrations. Interestingly, preincubation of FVIII with Gal-1 (0.5-17µM) resulted in a significant dose-dependent prolongation of the APTT (58 ± 0.2 sec compared to 26 ± 3 secs, p<0.001) In contrast, no such effect was observed for galectin-3 up to 20µM, suggesting these galectins may have differential effects on FVIII biology. In conclusion, we identify Gal-1 and Gal-3 as novel direct ligands for human FVIII. Both the N- and O-linked carbohydrates of FVIII contribute to galectin binding. Importantly, different commercial FVIII concentrates do not interact with galectins in the same manner. Finally, we also demonstrate that plasma FVIII can circulate in complex with both Gal-1 and Gal-3, and that Gal-1 binding can inhibit the procoagulant function of FVIII. Disclosures: No relevant conflicts of interest to declare.
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Ramasamy, Ranjan. "Mosquito vector proteins homologous to α1-3 galactosyl transferases of tick vectors in the context of protective immunity against malaria and hypersensitivity to vector bites". Parasites & Vectors 14, n.º 1 (5 de junio de 2021). http://dx.doi.org/10.1186/s13071-021-04801-7.
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Abstract Background An epitope, Galα1-3Galβ1-4GlcNAc-R, termed α-gal, is present in glycoconjugates of New World monkeys (platyrrhines) and other mammals but not in hominoids and Old World monkeys (catarrhines). The difference is due to the inactivation of α1-3 galactosyl transferase (α1-3 GT) genes in catarrhines. Natural antibodies to α-gal are therefore developed in catarrhines but not platyrrhines and other mammals. Hypersensitivity reactions are commonly elicited by mosquito and tick vector bites. IgE antibodies against α-gal cause food allergy to red meat in persons who have been exposed to tick bites. Three enzymes synthesising the terminal α1-3-linked galactose in α-gal, that are homologous to mammalian α and β1-4 GTs but not mammalian α1-3 GTs, were recently identified in the tick vector Ixodes scapularis. IgG and IgM antibodies to α-gal are reported to protect against malaria because mosquito-derived sporozoites of malaria parasites express α-gal on their surface. This article explores the possibility that the α-gal in sporozoites are acquired from glycoconjugates synthesised by mosquitoes rather than through de novo synthesis by sporozoites. Methods The presence of proteins homologous to the three identified tick α1-3 GTs and mammalian α1-3 GTs in two important mosquito vectors, Aedes aegypti and Anopheles gambiae, as well as Plasmodium malaria parasites, was investigated by BLASTp analysis to help clarify the source of the α-gal on sporozoite surfaces. Results Anopheles gambiae and Ae. aegypti possessed several different proteins homologous to the three I. scapularis proteins with α1-3 GT activity, but not mammalian α1-3 GTs. The putative mosquito α1-3 GTs possessed conserved protein domains characteristic of glycosyl transferases. However, the genus Plasmodium lacked proteins homologous to the three I. scapularis proteins with α1-3 GT activity and mammalian α1-3 GTs. Conclusions The putative α1-3 GTs identified in the two mosquito vectors may synthesise glycoconjugates containing α-gal that can be transferred to sporozoite surfaces before they are inoculated into skin during blood feeding. The findings merit further investigation because of their implications for immunity against malaria, hypersensitivity to mosquito bites, primate evolution, and proposals for immunisation against α-gal. Graphic abstract
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Chen, Qiushi, Han Liu y Xuechen Li. "Essential functions, syntheses and detection of sialyl Lewis X on glycoproteins". Exploration of Drug Science, 28 de febrero de 2023, 31–54. http://dx.doi.org/10.37349/eds.2023.00004.
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It is widely acknowledged that sialyl Lewis X (sLeX), the composition and linkage of which are N-acetylneuraminic acid (Neu5Ac) α2-3 galactose (Gal) β1-4 [fucose (Fuc) α1-3] N-acetylglucosamine, is usually attached to the cell surface. It presents as a terminal structure on either glycoproteins or glycolipids and has been demonstrated to be related to various biological processes, such as fertilization and selectin binding. Due to the vital role of sLeX, its synthesis as well as its determination approaches have attracted considerable attention from many researchers. In this review, the focus is sLeX on glycoproteins. The biological importance of sLeX in fertilization and development, immunity, cancers, and other aspects will be first introduced. Then the chemical and enzymatic synthesis of sLeX including the contributions from more than 15 international research groups will be described, followed by a brief view of the sLeX detection focusing on monosaccharides and linkages. This review is valuable for those readers who are interested in the chemistry and biology of sLeX.
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Kawakita, Chieko, Koki Mise, Yasuhiro Onishi, Hitoshi Sugiyama, Michihiro Yoshida, Masao Yamada y Jun Wada. "Novel urinary glycan profiling by lectin array serves as the biomarkers for predicting renal prognosis in patients with IgA nephropathy". Scientific Reports 11, n.º 1 (9 de febrero de 2021). http://dx.doi.org/10.1038/s41598-020-77736-1.
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AbstractIn IgA nephropathy (IgAN), IgA1 molecules are characterized by galactose deficiency in O-glycans. Here, we investigated the association between urinary glycosylation profile measured by 45 lectins at baseline and renal prognosis in 142 patients with IgAN. The primary outcome was estimated glomerular filtration rate (eGFR) decline (> 4 mL/min/1.73 m2/year), or eGFR ≥ 30% decline from baseline, or initiation of renal replacement therapies within 3 years. During follow-up (3.4 years, median), 26 patients reached the renal outcome (Group P), while 116 patients were with good renal outcome (Group G). Multivariate logistic regression analyses revealed that lectin binding signals of Erythrina cristagalli lectin (ECA) (odds ratio [OR] 2.84, 95% confidence interval [CI] 1.11–7.28) and Narcissus pseudonarcissus lectin (NPA) (OR 2.32, 95% CI 1.11–4.85) adjusted by age, sex, eGFR, and urinary protein were significantly associated with the outcome, and they recognize Gal(β1-4)GlcNAc and high-mannose including Man(α1-6)Man, respectively. The addition of two lectin-binding glycan signals to the interstitial fibrosis/tubular atrophy score further improved the model fitness (Akaike’s information criterion) and incremental predictive abilities (c-index, net reclassification improvement, and integrated discrimination improvement). Urinary N-glycan profiling by lectin array is useful in the prediction of IgAN prognosis, since ECA and NPA recognize the intermediate glycans during N-glycosylation of various glycoproteins.