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PubMed2000

Characterization of the glycoconjugates of boar testis and epididymis.

Lectin histochemistry was used to perform in situ characterization of the glycoconjugates present in boar testis and epididymis. Thirteen horseradish peroxidase- or digoxigenin-labelled lectins were used in samples obtained from healthy fertile boars. The acrosomes of the spermatids were stained intensely by lectins with affinity for galactose and N-acetyl-galactosamine residues, these being soybean, peanut and Ricinus communis agglutinins. Sertoli cells were stained selectively by Maackia ammurensis agglutinin. The lamina propria of seminiferous tubules showed the most intense staining with fucose-binding lectins. The Golgi area and the apical part of the principal cells of the epididymis were stained intensely with many lectins and their distribution was similar in the three zones of the epididymis. On the basis of lectin affinity, both testis and epididymis appear to have N- and O-linked glycoconjugates. Spermatozoa from different epididymal regions showed different expression of terminal galactose and N-acetyl-galactosamine. Sialic acid (specifically alpha2,3 neuraminic-5 acid) was probably incorporated into spermatozoa along the extratesticular ducts. These findings indicate that the development and maturation of boar spermatozoa are accompanied by changes in glycoconjugates. As some lectins stain cellular or extracellular compartments specifically, these lectins could be useful markers in histopathological evaluation of diseases of boar testis and epididymis.

Acrosome↗
PubMed2000

Altered expression of jack fruit lectin specific glycoconjugates in benign and malignant human colorectum.

Lectins bind to terminal non reducing sugars of glycoconjugates in cell membranes and secretions. These glycoproteins can be very characteristic, both for the differentiation state of a tissue and for its grade of malignancy. The carbohydrate structures of cellular glycoconjugates in normal, adenoma, and carcinoma of human colorectum were analysed using HRP conjugated Jack Fruit Lectin (JFL). Fifty two rectal carcinomas, 18 adenomas and 25 normal rectal tissues were used for the study. Diaminobenzidine (DAB) was used as the visualant. Normal rectal tissues showed positive reaction with intense staining in more than 60% of the cells. Adenomas were seen to have moderate to intense staining with a range of 30 to 60% positive cells. The lowest levels of JFL staining were observed in invasive tumours. JFL binding was found to decrease with carcinomatous cells compared to adenomas and normal cells. A significant negative association was found between JFL binding and histologic abnormality (r = -0.85, P <0.0000). These results suggest that there are alterations in the carbohydrate structures of cellular glycoconjugates, which can be related to goblet cell differentiation, in normal, benign and malignant human colorectal tissue.

Adenocarcinoma↗
PubMed2001

[Physico-chemical properties and biological activities of a glycoconjugate SPPA-1 from Spirulina platensis].

AIM: To isolate polysaccharide from Spirulina platensis and determine its sugar position, molecular weight and biological activities. METHODS: Sephadex G-75 and CM-Sephadex C-50 were used. The sugar position was analyzed by gas chromatography, the molecular weight was determined by GPC. The homogeneity of this glycoconjugate was determined by HPLC and CE. IR and NMR spectra were used to determine the glycosidic linkage. RESULTS: SPPA-1 was a homogeneous glycoconjugate, its carbohydrate chain was composed of alpha-glucopyranan, carbohydrate content is 91.70%, Nitrogen content was 0.96%, the molecular weight was 69.00 x 10(4), SPPA-1 could eliminate O2-. radicals. CONCLUSION: SPPA-1 was an antioxidative glycoconjugate from Spirulina platensis.

Amino Acids↗
PubMed1992

[Molecular biology of glycoconjugates in eukaryotic cells].

Glycoconjugates, such as glycoproteins and glycolipids, are one of the macromolecules composing a living body. Biological roles of carbohydrate moieties in glycoconjugates have recently drawn great attention. Sugar chains of glycoconjugates comprise an enormous diversity of structures which are known to be expressed in a cell specific manner and are regulated with stage specificity during embryogenesis and cell-differentiation. It is generally accepted that genetic expression and regulation of glycosyltransferases which are present in Golgi apparatus determines the structures of sugar chains. For these several years, a number of successes of cDNA cloning of glycosyltransferases have been reported. Recent progress and accumulated molecular cloning evidences of glycosyltransferases are reviewed and future advance using cloned genes as useful tools for glycobiology and glycotechnology is discussed.

ABO Blood-Group System↗
PubMedDate not supplied

Glycoconjugate expression in normal human inferior turbinate mucosa: a lectin histochemical study.

BACKGROUND: Further study on the composition and concentration of normal nasal mucosal glycoconjugates is needed. METHODS: A battery of ten lectins was used to stain six carbohydrates residing in the inferior turbinate mucosa of 21 healthy individuals. RESULTS: The concentrations of glycoconjugates of the glycocalyx exceeded that of epithelial goblet, ciliated, and basal cells, and also of mucous, serous, and mixed submucosal glands. Epithelial goblet cells and submucosal mucous glands contained relatively high concentrations of glycoconjugates, whereas in epithelial ciliated and basal cells, similar to serous and mixed submucosal glands, concentrations were scanty. The concentrations of N-acetylgalactosamine and galactose were higher in goblet cells than in mucous glands (p = 0.006, and p = 0.056, respectively). Differences in the concentrations of N-acetylglucosamine, fucose, mannose, and sialic acid were insignificant. CONCLUSIONS: The findings provide a baseline for comparison of the composition and concentration of carbohydrates of the normal and pathologic inferior turbinate mucosa.

Glycoconjugates↗
PubMed1989

Metabolism of glycoconjugates in human gastric mucosa a review.

Glycoconjugates, viz. glycoproteins, glycolipids and proteoglycans, play an important role in the protection of human gastric mucosa against pepsin and hydrochloric acid. The biosynthesis and catabolism of these compounds in the human gastric mucosa have been studied. We isolated and identified the majority of the intermediates and isolated some enzymes, taking part in the biosynthesis of glycoconjugates in the human gastric mucosa, and have demonstrated that the human gastric mucosa is able to release reducing sugars from glycoconjugates and shows some glycosidase activity.

Carbohydrate Conformation↗
PubMed1989

Lectin histochemistry of secretory cell glycoconjugates in the nasal mucosa of Podarcis sicula campestris De Betta (Reptilia, Lacertidae).

Histochemical study by traditional staining methods (AB, PAS, HID) and by the use of five peroxidase-labelled lectins (ConA, WGL, WPL, SBL, PNL) were carried out to characterize glycoconjugates in the secretory cells of the nasal mucosa of the Lacertid lizard Podarcis sicula campestris De Betta. The mucus covering the nasal epithelium is produced by the supporting cells and the Bowman glands in the olfactory area, and by typical goblet cells and, probably, a second type of secretory cell, in the non-sensory area. Neutral glycoconjugates containing N-acetyl-D-glucosamine and terminal N-acetyl-D-galactosamine, D-mannose and D-glucose residues were present in the secretory product of the Bowman glands. L-fucose and D-galactose were absent. In the supporting cells the secretory product consisted mainly of sulfated glycoproteins containing D-galactose, N-acetyl-D-galactosamine, N-acetyl-D-glucosamine, D-mannose, D-glucose, but not L-fucose. Glycoconjugates containing terminal sialic acid and penultimate D-galactose were present in typical goblet cells as was N-acetyl-D-glucosamine.

Animals↗
PubMed1988

Cellular glycoconjugates and their potential endogenous receptors in the cerebral microvasculature of man: a glycohistochemical study.

Protein-carbohydrate interactions are supposed to play a pivotal role in mediation of recognitive interactions, relevant to cellular interactions and transport. The brain microvasculature is the site of numerous cell-cell and cell-matrix recognitive interactions. Assuming carbohydrate-protein interactions play important physiological roles here, then specific carbohydrate-binding proteins should be prominent components of this microvasculature, in addition to the wealth of endogenous glycoconjugates reported by other authors. Human brain and brain tumor microvessels were analyzed histochemically for expression of endogenous sugar-binding proteins using a panel of biotin-conjugated, chemically glycosylated probes with specificities for alpha-/beta-D-galactosides and -D-glucosides, alpha-L-fucosides, alpha-D-mannosides, and beta-D-xylosides, and for expression of endogenous glycoconjugates using a panel of biotin-conjugated plant lectins with specificities for fucoside, galactoside, mannoside and glucoside moieties. Wax-embedded aldehyde- or Bouin-fixed tissues or acetone-fixed frozen sections were examined. Blood-brain barrier function was checked by ascertaining immunohistochemically the extravasation of serum albumin in these tissues. Microvessels in normal human brain tissues (with intact blood-brain barrier) contained abundant endogenous sugar-binding proteins with specificities for beta-galactosides, alpha-mannosides and beta-xylosides, and lesser amounts of proteins binding alpha-galactosides, alpha-fucosides and glucosides. Endogenous glycoconjugates bearing beta-galactoside, alpha-D-mannoside/alpha-D-glucoside or alpha-L-fucoside moieties were also abundant. In brain tumors (with defective blood brain barrier) the microvessels contained altered patterns of endogenous sugar-binding proteins, particularly noticeable in glioblastomas, in which there were notable alterations in galactoside-binding proteins in the microvessels.

Adult↗
PubMed1988

Characterization of colonic cellular glycoconjugates in colitis and cancer-prone tamarins versus colitis and cancer-resistant primates.

Differences in colonic secretory glycoconjugates (ie, mucin) between normal and ulcerative colitis-prone patients have been noted. Similar differences may occur in a corresponding primate model, the cotton-top tamarin (CTT), Saguinus oedipus, a New World monkey which suffers from spontaneous chronic colitis and colon cancer. Lectin reagents were used to characterize and compare colonic cell surface, cytoplasmic, and secretory glycoconjugates of 9 clinically healthy cotton-top tamarins, 7 colitis-susceptible, cancer-resistant tamarins (Callithrix jacchus, Saguinus fuscicollis), and 8 colitis and cancer-resistant primates (Aotus trivirgatus, Saimiri sciureus, Macaca fascicularis, and Macaca mulatta). Paraffin-embedded colonic sections were labeled with ten different biotinylated lectins and visualized by the avidin-biotin peroxidase (ABC) method. Significant differences were demonstrated in the pattern of lectin staining between the colitis-resistant and colitis-prone groups of primates. The differences were noted with Griffonia simplicifolia-I (GS-I), Dolichos biflorus agglutinin (DBA), peanut agglutinin (PNA) before and after neuraminidase, Ricinus communis agglutinin-I (RCA-I), soybean agglutinin (SBA), Ulex europaeus agglutinin-I (UEA-I), wheat germ agglutinin (WGA), and succinylated WGA (S-WGA). Significant differences between the CTT and phylogenetically related colitis-prone but cancer-resistant tamarins were demonstrated with SBA, UEA-I, and PNA after desialylation with neuraminidase. These results suggest that differences in colonic cellular glycoconjugates between colitis- and cancer-susceptible species versus colitis-susceptible, cancer-resistant species may be associated with risk of cancer.

Animals↗
PubMed1988

Glycoconjugate distribution in normal human endometrium. A lectin histochemical study.

A battery of nine lectins was applied to routinely processed endometrial biopsies to evaluate changes in glycoconjugate expression during the menstrual cycle and early gestation. Specific staining patterns emerged for glands, surface epithelium, predecidual and decidual cells, stromal granulocytes, and endothelium. Three lectins--wheat germ agglutinin (WGA), Ricinus communis-I (RCA-I), and Concanavalin ensiformis (Con-A)--showed consistent binding to epithelial and stromal cells in the menstrual cycle. WGA and RCA were bound to gland secretions whereas Con-A labeled epithelial cytoplasm. These three lectins stained occasional stromal cells early in the cycle, but WGA and RCA marked granulocytes whereas Con-A labeled predecidua in the late secretory phase. Succinylated WGA had a distribution similar to WGA but lacked its consistency and intensity. In the menstrual cycle peanut agglutinin reacted with ciliated cells. In addition, this lectin along with soybean agglutinin and Dolichos biflorus labeled gland secretions in pregnancy. The remaining lectins, Phaseolus vulgaris leucoagglutin and Ulex europaeus, marked some components, especially endothelium, but generally had less reactivity than the other lectins did. The results indicate that glycoconjugate production is correlated with the functional status of the endometrium. Presumably these glycoconjugates play a role in endometrial development necessary for nidation, and alterations in lectin distribution may reflect functional abnormalities not apparent by light microscopic study.

Adult↗
PubMed1993

[Cellular expression of CFTR in cystic fibrosis: defective cyclic AMP-dependent regulation of glycoconjugate secretion in cystic fibrosis fetal tracheal epithelial cells transfected by SV40 large T oncogene].

Epithelial tracheal cells isolated from two fetuses with cystic fibrosis (CF) and non-CF fetus (control) were transfected with a plasmid vector recombined with the large T oncogene of SV40. All transfected cells expressed SV40 antigen and exhibited an epithelial morphology (junctional complex, cytokeratins). CFT cells retained the mutations of the CF gene, one heterozygous for the S549N/N1303K substitutions (CFT-1 cells), the other homozygous for the deletion delta F508 (CFT-2 cells). Accordingly, these CFT cells exhibited the defective beta-adrenergic regulation of chloride conductance. We compared the responsiveness of control (NT-1 cells) and CF cells (CFT-1 and CFT-2 cells) to agonists of the protein kinase A (PKA)-dependent pathway for stimulation of glycoconjugate secretion. We show that the isoproterenol (10(-5) M) and forskolin (10(-5) M) markedly increased the cAMP content and the PKA activity of all three cell lines. In contrast, these effectors produced an increase in glycoconjugate secretion in control cells, but not in CFT-1 and CFT-2 cells. In conclusion, our results indicate that CFT cells do not respond to agonists of the PKA-dependent pathway for stimulation of both glycoconjugate secretion and chloride transport, which suggests the involvement of CFTR in these two processes.

Cells, Cultured↗
PubMed1995

Expression of membrane glycoconjugates on sheep lung endothelium.

BACKGROUND: Carbohydrates play an important role in both the regulation and expression of endothelial cell surface molecules. EXPERIMENTAL DESIGN: To investigate the molecular phenotype of endothelial cells in the sheep lung, we used a panel of 39 lectins and carefully titrated lectin histochemistry to identify small vessel glycoconjugates. Expression of glycoconjugates on isolated cells was studied by flow cytometry and lectin Western blotting. RESULTS: Eight lectins stained small vessel endothelium with minimal background staining. To confirm cell surface binding, endothelial cells from the peripheral lung were isolated and tested for lectin recognition by flow cytometry. Three lectins (Datura stramonium, Griffonia simplicifolia-1, Lycopersicon esculentum) also stained isolated lung cells by flow cytometry. A lectin Western transfer technique demonstrated common binding to a high molecular weight (100 to 130 kD) band. CONCLUSIONS: The use of lectins as probes of cell surface carbohydrate expression supports the possibility of selective glycoconjugate expression on sheep endothelium.

Animals↗
PubMed1993

[Abnormal expression of glycoconjugate associated with the development of endometrial cancer: a basic study and its usefulness in clinical application].

We studied the abnormal expression of a glycoconjugate that appears in the process of neoplasia of endometrial cells and tried to shed light on the mechanism of their expression. Furthermore, we evaluated the effectiveness of its use in clinical application. 1. Investigation of abnormal expression of glycoconjugate We performed an immunohistochemical study on the expression of blood group-related carbohydrate antigens in endometrial cells, and found that carbohydrate side chains with galactose and fucose at their terminals were increased in association with neoplastic transformation. Using anti-endometrial cancer monoclonal antibody MSN-1, we showed that abnormal expression had already been induced in endometrial hyperplasia and increased as the lesions grew worse. A biochemical study of glycolipids showed that sulfatide (one of the sulfoglycolipids) was produced in endometrial cells, and that it varied in amount depending on the menstrual cycle, and was increased in endometrial cancer cells. Hydroxylation, which is recognized in cells in the fetal period, was seen in the ceramide region of these glycolipids. 2. Shedding light on the mechanism of the abnormal expression of glycoconjugate We examined normal and neoplastic endometrial cells for differences in the level of galactosyltransferase (GT) and fucosyltransferase (FT). Immunohistochemical staining with monoclonal antibody 8628 (an anti-GT antibody) gave the following results: GT gave a fine granular staining confined to the cytoplasma between the nucleus and glandular lumen in 70% of the cares of normal endometrium: In contrast, GT was found extensively in either a coarse granular state or spread diffusely throughout the cytoplasm in about 70% of the endometrial cancer specimens. We were also able to determine FT activity in normal and cancerous endometrial tissues by our newly developed method. The levels of alpha1-2FT, alpha 1-3FT and alpha 1-4FT were higher in endometrial cancer than in normal endometrium. Furthermore, we determined the activity of alpha 1-2FT and alpha 1-4FT in both endometrial cancer tissue and cell cultures derived from gynecological cancer, and examined the relationship between their activity levels and expression of the antigen recognized by MSN-1. There was a positive correlation between them. SNG-II cells were classified in terms of their reactivity to MSN-1 into two groups: 1) SNG-S, which was strongly reactive to MSN-1, and 2) SNG-W, which was weakly reactive to the antibody. FT activity was compared between these two cell groups. There was a marked difference in alpha 1-4FT activity between these two groups.(ABSTRACT TRUNCATED AT 400 WORDS)

Antibodies, Monoclonal↗
PubMed1996

Glycoconjugate expression changes during Rana dalmatina early development.

Glycoconjugates are generally involved in cell adhesion and morphogenetic movements. To investigate their distribution and expression changes during amphibian development, several FITC-or HRP-labeled lectins were used in Rana dalmatina embryos and larvae. During gastrulation, WGA, ConA, HPA, GSA-I, PNA and RCA-I labeled either the envelopes on the perivitelline space-contained substances, while ectodermal cells and/or extracellular matrix were mainly labeled by WGA, GSA-I, DBA and LTA. In these structures fibronectin-like molecules were also found. ConA, HPA, RCA-I, SBA also labeled ectoderm, but with lower affinity. At larval stages, ectodermal derivatives, such as larval skin, central nervous system, eye and ear, were also strongly labeled by WGA, DBA and LTA, while the affinity to ConA, HPA, GSA-I, SBA, appeared less visible; the affinity sites to RCA-I and PNA were totally lacking. Fibronectin-like immunoreactivity was hardly present at the larval stages. These results point out that glycoconjugate expression changes in cell surface and in extracellular matrix might be developmentally regulated. For this reason the different glycoconjugates seem to play stage-specific roles in early development.

Animals↗
PubMed1997

[Lectin histochemistry of the glycoconjugates in conjunctival goblet cells].

The distribution of O- and N-linked glycoconjugates in human conjunctival goblet cells was examined histochemically using biotinylated and fluorescence-labeled lectins simultaneously. Both peanut agglutinin and Erythrina cristagalli agglutinin, specific for O- and N-linked sugar chains, respectively, bound to the same goblet cell, which demonstrated that a conjunctival goblet cell produces and contains both types of glycoconjugates. Maackia amurensis lectin II, specific for sialic acid alpha 2, 3 galactose, bound to the goblet cells, while Sambueus nigra agglutinin, specific for sialic acid alpha 2, 6 galactose, did not. This observation suggested that the terminal galactosyl residue of the glycoconjugates is alpha 2, 3-sialylated in the human conjunctival goblet cells.

Conjunctiva↗
PubMed1997

Detection of glycoconjugates in the ductus epididymis of the prepubertal and adult horse by lectin histochemistry.

This paper describes an approach for studying the structure of glycoconjugates found in the principal cells lining the epididymal duct in adult and prepubertal horses, using ten different lectin horseradish conjugates: Con-A, LCA, WGA, GSA-II, SBA, PNA, RCA-I, DBA, UEA-I, and LTA. Saponification and sialidase procedures, followed by lectin binding, were employed to visualize the distribution and to reveal the sequence of sialoglycoconjugates in ductus epididymis. In the adult horse the results demonstrated variations in the content and distribution of glycosidic residues of glycoconjugates in different epididymal regions (caput, corpus, cauda) and vas deferens, suggesting that each epididymal segment has a specific function. In particular, staining of the Golgi-zone in the principal cells lining corpus epididymis was interpreted as evidence for synthesis and secretion of glycoconjugates and sialoglycoconjugates. In the prepubertal horse, only the glycocalyx of the epithelial cells lining the epididymal duct showed reactivity toward the different lectins used, suggesting hormonal regulation of the epididymis activity. Additional, the heterogeneity of the lectin staining pattern of the adult horse epididymis reported in this investigation also suggests the existence of different functional segments along the epididymal duct.

Animals↗
PubMed1997

Distribution of glycoconjugates in the uterine tube (oviduct) of horses.

OBJECTIVE: To examine glycoconjugates in the isthmic and ampullar regions of the uterine tube (oviduct) of horses during estrus, diestrus, and pregnancy. SAMPLE POPULATION: Oviductal samples from 17 mares. PROCEDURE: Oviducts were collected during estrus (n = 3), diestrus (n = 3), or pregnancy (n = 3), embedded, and snap frozen in liquid nitrogen. Frozen sections (5 to 6 microns in thickness) were stained with 100 micrograms/ml of fluorescein-isothiocyanate-conjugated lectin (30 min at 38.5 C) and were evaluated by use of epifluorescence microscopy and video image analysis. Specificity of lectins was established by blocking with the corresponding carbohydrate. Dolichos biflorus agglutinin (DBA)-affinity studies on western blots of oviductal lavage fluid, oviductal explant conditioned media, and apical membrane proteins from isthmic and ampullar regions of oviducts were used to identify glycoproteins with galactosyl residues. RESULTS: Use of 4 lectins resulted in differential labeling of the luminal surface of the oviductal epithelium. Both DBA and soybean agglutinin labeled the apical epithelium of the isthmus, but not the ampullar oviduct. Soybean agglutinin resulted in more-intensely labeled epithelium in the isthmic region of oviducts during estrus and pregnancy than during diestrus. The DBA labeled a number of glycoproteins in conditioned media from both regions of the oviduct. These glycoproteins ranged from 14 to 200 kd, with major glycoproteins identified at 31 and 57 kd. CONCLUSIONS: The predominant glycoconjugates in the oviduct of horses are galactosyl residues. There are regional differences in the distribution of these galactosyl glycoconjugates in the isthmic and ampullar oviduct.

Animals↗
PubMedDate not supplied

An investigation of the nature of bladder mucosal glycoconjugates and their role in interstitial cystitis.

The long-term objective of this study is to elucidate the role of bladder mucosal glycosaminoglycans and mucin glycoproteins in the development of interstitial cystitis and other bladder diseases. Bladder biopsies and urine samples from patients and healthy controls were analyzed for glycoconjugates by biochemical and immunochemical methods. Due to the limited availability of human bladders for research purposes, detailed analysis of rabbit bladders glycoconjugates were also carried out. Biochemical analysis of rabbit bladders indicate that while the major portion of the glycoconjugates in the urothelium is sialoglycoprotein, low levels of heparan sulfate and chondroitin sulfate are also present. The correlating immunohistochemical data show very weak staining of the rabbit bladder epithelium by antiglycosaminoglycan antibodies. In contrast, the lamina propria and muscle layers stained intensely for chondroitin sulfate and hyaluronic acid. Thus, the quantity of glycosaminoglycans associated with the bladder epithelial layer, particularly as extracellular matrix components on the luminal surface of the bladder, appears insignificant. On the other hand, several lectins and anti-epitectin (a MUC1 sialoglycoprotein) antibodies showed strong staining of the luminal surface of rabbit and normal human bladders. Further, preliminary results with anti-epitectin antibodies reveal a weaker and patchy staining of biopsy specimens from interstitial cystitis patients compared to controls. The urinary levels of glycosaminoglycans and epitectin, in interstitial cystitis patients and healthy controls were determined by chemical or immunoassays. Urinary epitectin, but not glycosaminoglycans, was decreased in interstitial cystitis patients.

Animals↗