Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.1.53 (sialidase)
2,694 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Sugar specific lectins (PNA, RCA I, LPA, SBA, DBA, GSA IB4, GSA II, WGA, LTA, UEA I, Con A, LCA) with and without prior selective glycosidase digestion (sialidase, alpha-fucosidase, alpha-mannosidase, beta-N-acetylglucosaminidase, alpha- and beta-galactosidase, beta-glucosidase) were used in order to investigate the distribution of native accessible carbohydrates and obtain information dealing with the composition of terminal disaccharides within glycoconjugates present in acinar compartments and ductal segments of mammalian (mouse, rat, hare, and rabbit) parotid glands. Glycoconjugates containing variable amounts of mannose, glucose, N-acetylgalactosamine and N-acetylglucosamine were present in the parotid glands of all species. However, these carbohydrate chains exhibited a different composition of terminal sequences within each type of gland. For example, sialylated components having the terminal dimers sialic acid-galactose and sialic acid-N-acetylgalactosamine were found in all acinar cells, whereas fucoglycoconjugates with terminal disaccharide fucose-galactose were localized in the rat striated ducts and hare acinar cells. The terminal sequence alpha-galactose-beta-galactose was demonstrated in the mouse acinar cells. Finally, glycoconjugates characterized by the terminal dimer beta-galactose-N-acetylgalactosamine were demonstrated in the mouse acinar and ductal cells and the rat ductal ones. Thus, present findings outlined and further confirmed the possibility to elucidate the oligosaccharide structure in situ using lectin histochemistry combined with enzymatic degradation.
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PMID:Glycoconjugate composition of mammalian parotid glands elucidated in situ by lectins and glycosidases. 137 7

In recent years histochemical methods using lectins with diverse carbohydrate binding specificities have proved useful tools for studying the distribution pattern of intracellular and pericellular glycoconjugates at the tissue level. Several studies of human kidneys have shown that the binding sites for certain lectins are strictly confined to various parts of the nephron. This allows the use of lectins as markers for the particular segments. The glomeruli exhibit abundant sialoglycoproteins at the free surface coat of the podocytes as detected by PNA after sialidase representing a major component of the filtration barrier; neoplastic podocytes of glomeruloid bodies in nephroblastomas as well revealed an intense lectin binding despite failing any vascularization. The lectin binding pattern of renal carcinomas varies within a wide range depending on their histological growth pattern. Whereas most renal carcinomas of clear and granular cell type rarely displayed a slight reactivity with lectins at the cell surface and at the luminal aspect of tubulopapillary tumors, a sub-group of carcinomas named chromophobe type exhibited a strong cytoplasmic staining with DBA and PNA after sialidase. Comparative evaluation of normal kidneys revealed an identical binding pattern exclusively in the intercalated cells of the collecting ducts probably indicating a histogenetic origin of these tumors from the collecting duct epithelium. This assumption derives further support from the detection of precursor lesions rarely detected in normal and tumor-bearing kidneys exhibiting the same lectin binding pattern. In accordance with recent observations in the literature the disclosure of a similar lectin binding pattern in renal oncocytomas and their precursor lesions exhibiting oncocytic transformation clearly favors the assumption of an identical histogenetic origin. On the other hand, few cases of a carcinoma mimicking collecting duct epithelium exhibited a broader lectin binding pattern revealing evidence of secretory activity; the histochemical similarities between this unusual carcinoma and transitional cell carcinoma confirmed the suggested origin from the ducts of Bellini. In conclusion, lectin histochemistry may be a useful tool for estimating the characteristics of renal tumors and elucidating their histogenesis.
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PMID:[Lectin histochemistry in the kidney and renal tumors]. 248 19

The present study investigated some lectin affinities of human dental pulps, especially of odontoblasts and pulp cells. The materials were obtained from clinically intact teeth that were caries-free, attrition and/or abrasion-free. Mucopolysaccharide staining was carried out with applied PAS and alcian blue (AB) (pH 1.0 and 2.5). Lectins used were Con A, WGA, RCA-1, UEA-1, DBA, SBA, MPA, LFA, HPA, PNA, and GS-1, and the avidin-biotin peroxidase complex method was employed. Some specimens were tested for PNA binding after treatment with sialidase. The following results were obtained: 1) On PAS and AB staining, the pulp tissue was very weakly or borderline positive. 2) Lectin binding in odontoblasts was intensely positive with Con A, WGA, RCA-1, MPA, and LFA, but negative or very weakly positive with the other lectins examined. 3) Lectin localization in odontoblasts was localized diffusely throughout the cytoplasm. 4) On PNA staining, odontoblasts were negative, but changed to positive after treatment with sialidase. 5) Odontoblast processes showed negative or borderline staining with all lectins used in this study. 6) The pulp cells were clearly positive with Con A, MPA, LFA, RCA-1, and SBA and especially LFA showed an intense reaction with the pulp cells. 7) WGA affinity for odontoblasts was very strong but that for pulp cells was very weak. 8) Lectin binding in pulp cells was observed mainly in the processes of the cells. From the above results, it is clear that the lectin binding pattern of odontoblasts differs from that of pulp cells. The data suggest that D-mannose, N-acetyl-D-glucosamine, D-galactose, and N-acetyl-D-galactosamine residues are localized in the odontoblasts and sialic acid is localized in the pulp cells.
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PMID:[Lectin histochemical study on human dental pulp. Special reference to odontoblasts and pulp cells]. 248 77

Sites of binding of eight different lectins (LTA, UEA I, WGA, SBA, DBA, CON A, PNA, RCA I) to cat submandibular gland were studied after exposure of tissue sections to sialidase, alpha-fucosidase, beta-galactosidase, alpha-mannosidase, beta-N-acetylglucosaminidase. All lectins were affected by enzymatic predigestion and the labeling of individual lectins was highly dependent upon the glycosidase used to pretreat the sections. Glycoconjugates of demilunar, acinar and ductal cells exhibited a different composition of terminal sequences. For example, fucose proved to form the disaccharide fucose-galactose in demilunar and acinar cells, whereas it was present with the sequence fucose-N-acetyl-D-glucosamine in striated duct cells. Sialic acid participated both to the terminal sequence sialic acid-galactose and sialic acid-N-acetyl-D-galactosamine either in demilunar or in ductal cells. Lectin labeling combined with glycosidase digestion was also helpful in verifying the influence of neighbouring oligosaccharides on the affinity of lectins for the respective sugars.
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PMID:Enzymatic degradation and quantitative lectin labeling for characterizing glycoconjugates which act as lectin acceptors in cat submandibular gland. 271 45

Lectin binding affinities were described in human submandibular gland (SMG) in the paraffin sections following alpha-amylase, sialidase, and trypsin digestions. Lectins in the present study were used Con A (Glc, Man binding lectins), PNA, and SBA(Gal, GalNAc), RCA-1(Gal), DBA(GalNAc), WGA(GlcNAc), and UEA-1(Fuc). Lectin stainings in serous and mucous acinar cells and ductal epithelia were reported to compare enzyme treated and nontreated sections. Amylase treatment showed increasing Con A staining in connective tissue fibers and no marked changes in SMG to lectin bindings. Sialidase digestion was characteristically intense in PNA and SBA bindings in SMG cells, and also enhanced staining to UEA-1 in serous and duct cells and to WGA in mucous and duct cells were noted. Trypsin digestion indicated a slight increase to Con A binding, and was relatively strong to UEA-1 in serous and duct cells and a little strong to WGA. The results suggested that SMG serous cells contain higher amounts of Gal, GalNAc, and Fuc residues; and mucous cells were also abundant in Gal, GalNAc, and GlcNAc residues.
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PMID:Different bindings to lectin in human submandibular gland after enzymatic digestion. 308 93

Bacteroides fragilis SBT3182 produced two sialidases which differ in molecular weight on SDS-PAGE. These sialidases, a 50 kDa and a 55 kDa enzymes, were purified separately and their properties were compared. Both enzymes preferentially hydrolyze sialyl alpha 2-8 linkage rather than alpha 2-3 and alpha 2-6 bonds. The Km values for Neu5Ac alpha 2-3lactose, Neu5Ac alpha 2-6lactose, and colominic acid, which is a homopolymer of N-acetylneuraminic acid linked by alpha 2-8 bonds, were identical between the two enzymes. These enzymes had Km value of 1.0-1.2 mM for Neu5Ac alpha 2-3lactose and 1.3-1.5 mM for Neu5Ac alpha 2-6lactose, which are in the ranges reported for other sialidases. However, the Km values for colominic acid (0.03-0.04 mM) were lower than those of other sialidases, indicating that sialidases from B. fragilis SBT3182 show high affinity for the sialyl alpha 2-8 linkage. The two sialidases also had identical N-terminal amino acid sequences and did not reveal any homology to known sialidases. PAS-staining suggested that these two sialidases were glycoproteins. In the lectin analysis, the 50 kDa enzyme was stained with Con A, DBA, and UEA-I while the 55 kDa sialidase was stained only with Con A. This suggested that the difference in molecular weight may be due to the carbohydrate composition. When the 50 kDa enzyme was incubated with UEA-I, which is a lectin specific for alpha-fucose residue, the activity decreased by 20%.
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PMID:Two sialidases which preferentially hydrolyze sialyl alpha 2-8 linkage from Bacteroides fragilis SBT3182. 751 73

Morphological and histoenzymological differences have been observed between intercalated and principal cells of the quail Coturnix coturnix japonica collecting ducts. The present study was designed to shed light on the lectin affinity of the collecting duct cells within cortex and medulla by the use of HRP-labelled lectins combined with glycosidase degradation. Binding of PNA and RCA-I lectins consequent to enzymatic release of sialic acid revealed abundant sialylated carbohydrate moieties within the principal cell cytoplasm. This characteristic binding pattern differed considerably from the staining observed in the intercalated cells. Interesting information also emerged about the presence of sialoglycoconjugates having the terminal disaccharide sialic acid-beta-N-acetylgalactosamine originating from the increased SBA binding and the unmodified DBA labelling after removal of sialic acid. Sequential degradation by sialidase/beta-galactosidase followed by incubation with DBA offered the possibility to suspect that the receptor sugar for the penultimate beta-galactose may be N-acetylgalactosamine. Conversely, we were not able to define the accept sugar for penultimate beta-GalNAc owing to the lack of availability of beta-N-acetylgalactosaminidase enzyme. When although further studies are clearly needed to elucidate the physiological role of the cellular sialoglycoconjugates detected, the present results already provide valuable insight into the carbohydrate composition of intercalated and principal cells in the quail collecting ducts.
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PMID:Mosaic lectin labelling in the quail collecting ducts. 754 Dec 64

Sialoglycoconjugates were investigated in the bovine sublingual gland by direct visualization of sialic acid with specific lectins (LPA, SNA) and by histochemical procedures combined with sialidase digestion and lectins. The most reactive histological structures were found to be acini which contained glycoconjugates with terminal disaccharides consisting of sialic acid linked to galactose or N-acetylgalactosamine. Resistance to periodate oxidation was interpreted as demonstrating a relevant presence of C7, C8 and C9 acetylated sialic acids. KOH-Sialidase-DBA and KOH-Alcian blue sequences allowed the identification of C4 acetylated sialic acids.
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PMID:Variety of sialic acids occurring in the bovine sublingual gland. 789 45

In the present work, gustatory glands (von Ebner's glands) of the horse tongue were examined by means of five peroxidase-conjugated lectins (PNA, DBA, SBA, UEA I, WGA), with and without prior sialidase digestion, in order to investigate the presence and distribution of carbohydrate residues in secretory cells and duct cells. The most intense staining of secretory cells was observed with PNA after pre-treatment with neuraminidase. This indicates that the terminal trisaccharide sequence sialic acid- (alpha 2-->3, 6) galactosyl (beta 1-->3) N-acetylgalactosamine is the most frequent oligosaccharide chain present in glycoproteins secreted by horse gustatory glands. Secretory cells also contained oligosaccharides with terminal alpha-N-acetylgalactosamine and N-acetylglucosamine, whereas fucose was found in only a few glandular cells. The apical cytoplasm of duct lining cells reacted with all the lectins except WGA.
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PMID:A lectin histochemical study of gustatory (von Ebner's) glands of the horse tongue. 858 3

The objective of this study was to characterize the glycoconjugates present in the zona pellucida of the follicular oocytes in sheep, goats and pigs. The zona pellucida was stained with periodic acid-Schiff, low iron diamine, high iron diamine, and nine different lectin horseradish conjugates: Con-A, SBA, DBA, PNA, RCA-I, GSA-II, WGA, LTA and UEA-I. Staining with DBA, PNA, SBA and RCA-I was performed with and without saponification with KOH and sialidase digestion. The results showed the presence of neutral and acidic glycoconjugates with different terminal sugars and also sialic acid radicals in the zona pellucida of all the animal studied. In particular, the positive staining with WGA, SBA, PNA and RCA-I suggests the presence of oligosaccharides with N-acetyl-D-glucosamine and sialic acid linked to the penultimate beta-N-acetyl-D-galactosamine and to the disaccharide galactosyl-(beta 1-3)-N-acetyl-D-galactosamine. The terminal trisaccharide sialic acid galactosyl-(beta 1-4)-N-acetyl-D-glucosamine was identified only in the zona pellucida of ovine and porcine oocytes. Thus, the zona pellucida exhibited species-specific variations in the content and distribution of lectin-binding patterns that may reflect the species specificity of gamete interaction.
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PMID:Characterization of the complex carbohydrates in the zona pellucida of mammalian oocytes using lectin histochemistry. 873 21


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