Browsing by Subject "Glycoproteins"

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    Histochemical aspects of the yol k-sac and digestive tract of larvae of the Senegal sole, Solea senegalensis (Kaup, 1858)
    (Murcia : F. Hernández, 1996) Sarasquete, C.; Gonzalez de Canales, M.L.; Arellano, J.M.; Muñoz-Cueto, J.A.; Ribeiro, L.; Dinis, M.T.
    Histochemical distribution of glycoproteins, carbohydrates and proteins rich in different aminoacids were studied using histological and histochemical procedures, in Senegal sole, Solea senegalensis (Kaup, 1858) larvae from hatching until day 15. Glycogen, proteins and glycoproteins were detected in the yolk-sac of the larvae at hatching and during the yolk-resorption. The epithelia1 digestive system (brush border, enterocytes and goblet cells) contained neutral and acid mucins (carboxylated andlor sulphated). Glycogen was observed in the cytoplasm of the digestive absortive cells (enterocytes) and in the liver (hepatocytes) on day 3-4 posthatching. Protein reactions, and specially those that showed proteins rich in arginine, tyrosine and tryptophan, were very intense in the zymogen granules of the pancreatic cells. Oesophageal and intestinal goblet cells contained glucose N-acetyl and sialic acid residues, but the mucin content of these mucous cells did not show affinity towards Con-A, suggesting the absence of glycoproteins with Mannose andlor glucose residues. WGA showed a very intense positivity in the microvilli of the digestive epithelium of the larvae and positive granules for both lectins, specially for Con-A, were detected in the cytoplasm of the anterior intestinal enterocytes.
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    Histochemical study of lymphocystis disease in skin of gilthead seabream, Sparus aurata L.
    (Murcia : F. Hernández, 1998) Sarasquete, C.; Gonzalez de Canales, M.L.; Arellano, J.M.; Pérez-Prieto, S.; García-Rosado, E.; Borrego, J.J.
    A battery of horseradish peroxidasecorijugated lectiris (Con A, WGA arid DBA). as well as coriventional histochemical techniques (PAS. saponification, Alcian Blue pH 0.1 , 1. 2.5. chlorhydric hydrolisis. sialidasc, Bromophenol blue, Tioglycollate reduction and Ferric-ferricyanide-FeIlI) were used to study the coritent and distribution of carbohydrates, proteins and glycoconjugatc sugar residues on the skin and on the lymphocystis-infected cells of gilthead seabrcain, Spcrrus uurntcr. Variable ari-iounts of glycoproteins containing sialic acid, N-acetyl-Dglucosainine, N-acetyl-D-galactosarnine; mannose andlor glucose residues were observed in the cuticle and mucous cells of the c o r ~ o r a ls kin. tails and f ins . ~ ~ Germinative and epithelial cells of the epidermis contained glycogen. proteins. carboxylated groups, as well as glycoproteins with mannose andlor glucose and N-acetyl-U-galactosamine residues. Hyaline capsule of the mature lyniphocystis-infected cells was strongly stained with PAS, Alcian Blue (pH 0.5 and 2.5) and weakly positive with Alcian Blue (pH 1 ) . Con A reacted with the granular cytoplasm, specially around hyaline capsule. and with the basophilic intracytoplasinic inclusions developed in mature lymphocystis-infected cells of Spcrrrrs crlirntu skin. These sugar residues (niannose andlor glucose), as well as N-acetyl-Drrlucosamine andlor sialic acid and N-acetvl-D- L galactosamine were not detected in the hyaline capsule of the lyr.iphocysti5 disease.
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    Hypoglycosylation is a common finding in antithrombin deficiency in the absence of a SERPINC1 gene defect
    (Elsevier, 2016) Morena Barrio, María Eugenia de la; Martínez Martínez, Irene; Cos, Carmen de; Wypasek, Ewa; Roldán, Vanessa; Undas, Anetta; Sherpenzeel, Monique van; Lefeber, Dirk; Toderici, Mara; Sevivas, Teresa; España, Francisco; Jaeken, Jaak; Corral, Javier; Vicente, Vicente; Medicina
    Essentials We investigated the molecular base of antithrombin deficiency in cases without SERPINC1 defects. 27% of cases presented hypoglycosylation, transient in 62% and not restricted to antithrombin. Variations in genes involved in N-glycosylation underline this phenotype. These results support a new form of thrombophilia. Click here to listen to Dr Huntington's perspective on thrombin inhibition by the serpins. Summary: Background Since the discovery of antithrombin deficiency, 50 years ago, few new thrombophilic defects have been identified, all with weaker risk of thrombosis than antithrombin deficiency. Objective To identify new thrombophilic mechanisms. Patients/methods We studied 30 patients with antithrombin deficiency but no defects in the gene encoding this key anticoagulant (SERPINC1). Results A high proportion of these patients (8/30: 27%) had increased hypoglycosylated forms of antithrombin. All N-glycoproteins tested in these patients (α1-antitrypsin, FXI and transferrin) had electrophoretic, HPLC and Q-TOF patterns indistinguishable from those of the congenital disorders of glycosylation (rare recessive multisystem disorders). However, all except one had no mental disability. Moreover, intermittent antithrombin deficiency and hypoglycosylation was recorded in five out of these eight patients, all associated with moderate alcohol intake. Genetic analysis, including whole exome sequencing, revealed mutations in different genes involved in the N-glycosylation pathway. Conclusions Our study provides substantial and novel mechanistic insights into two disease processes, with potential implications for diagnosis and clinical care. An aberrant N-glycosylation causing a recessive or transient antithrombin deficiency is a new form of thrombophilia. Our data suggest that congenital disorders of glycosylation are probably underestimated, especially in cases with thrombosis as the main or only clinical manifestation.
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    Quantitation and histochemical localization of galectin-1 and galectin-1 -reactive glycoconjugates in fetal development of bovine organs
    (Murcia : F. Hernández, 1997) Kaltner, H.; Lips, K.S.; Reuter, G.; Lippert, S.; Sinowatz, F.; Gabius, H.J.
    The display of cellular oligosaccharide chains is known to undergo marked developmental changes, as monitored histochemically with plant lectins. In conjunction with endogenous lectins respective ligand structures may have a functional role during fetal development. The assumption of a recognitive, functionally productive interplay prompts the study of the expression of a tissue lectin and of lectin-reactive glycoconjugates concomitantiy. Focusing on comrnon Bgalactosides as constituents of oligosaccharide chains and the predominant member of the farnily of galectins in marnrnals, namely galectin-1, the question therefore is addressed as to whether expression of lectin and lectinreactive glycoconjugates exhibits alterations, assessed in three morphologically defined fetal stages and in adult bovine organs. Using a sandwich ELISA, the leve1 of the rather ubiquitous galectin-1 is mostly increased in adult organs relative to respective fetal stages, except for the case of kidney. This developmental course is seen rather seldom, when the amounts of lectin-reactive glycoproteins or glycolipids are quantitated in solid-phase assays after tissue homogenization. Western blotting, combined with probing by labeled galectin-1, discloses primarily quantitative changes in the reactivity of individual glycoproteins. Perforrning the same assays on extract aliquots with a plant agglutinin, namely the galactoside-binding mistletoe lectin, whose fine specificity is different @m galectin-1, its reduced extent of binding in solid-phase assays and the disparate profile of lectin-reactive glycoproteins reveal a non-uniform developmental alteration within the group of stmctural variants of B-galactosides. Although sample preparation can affect ligand preservation andlor presentation and thus restricts the comparability of biochemical and histochemical results, especially for soluble reactants, the histochemical studies on frozen and paraffinembedded sections of bovine heart, kidney and liver demonstrate that the localization of the galectin and of lectin-reactive epitopes can show a sirnilar distribution, as seen in liver and heart, with organ-typical quantitative changes of a rather similar staining profile (heart, kidney) or notable changes in the spatial distribution (liver) in the course of development. This report emphasizes the potential value of combined monitoring of the lectin and its potential in vivo ligands to contribute to eventually unravel organ-related function(s) of a tissue lectin.
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    The role of carbohydrate residues in mammalian fertilization
    (Murcia : F. Hernández, 1997) Shalgi, R.; Raz, T.
    The fertilization process in mammals involves binding and fusion of free-swimming sperm and ovulated eggs. This review focuses on the role of carbohydrate residues in the process of sperm-egg interaction in mammals. The zona pellucida (ZP), the acellular glycoprotein coat surrounding the egg is highly glycosylated and posssess both Asn- (N-) linked and SerlThr- (O-)linked oligosaccharides, with an extreme structural heterogeneity between the different species. Different carbohydrates on ZP3, such as Galactose in a-linkage, N-acetylglucosamine in B-linkage, were suggested as the complementary sperm receptors, mediating the primary binding between the spermatozoon and the ZP. Several suggested complementary ZP3 binding proteins on the sperm are sp56, O-1,4-galactosyltransferase and p95. Some carbohydrate residues of the ZP undergo postfertilization modifications that might alter the sperm receptor, thus assisting in the establishment of the block to polyspermy. The studies summarized in this review imply a main role for the carbohydrate residues in the process of sperm egg interaction.