Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Glycoconjugates”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources
PubMed1994

Lectin histochemical localization of galactose, N-acetylgalactosamine, and N-acetylglucosamine in glycoconjugates of the rat vomeronasal organ, with comparison to the olfactory and septal mucosae.

The localization of alpha-D-galactose, N-acetyl-D-galactosamine, and N-acetyl-D-glucosamine sugar residues of glycoconjugates in the vomeronasal organ, olfactory mucosa, and septal organ in the nasal mucosae of rats was investigated using lectinohistochemical techniques combined with bright-field, epifluorescence, and confocal laser scanning microscopy. Glycoconjugates in the mucomicrovillar complex of the vomeronasal organ contained all the sugar residues investigated, whereas glycoconjugates in the mucociliary complex of the olfactory mucosa and septal organ contained only N-acetyl-D-glucosamine. Vomeronasal receptor neurons expressed glycoconjugates with terminal alpha-D-galactose and beta-N-acetyl-D-galactosamine, and N-acetyl-D-glucosamine residues, whereas olfactory and septal receptor neurons expressed glycoconjugates with only N-acetyl-D-glucosamine residues. Secretory granules of glands of the vomeronasal organ contained glycoconjugates with terminal alpha-D-galactose and N-acetyl-D-galactosamine, and N-acetyl-D-glucosamine, whereas those of the Bowman's glands and glands of septal organ contained glycoconjugates with only internal N-acetyl-D-glucosamine residues. The results demonstrate that the glycoconjugates expressed by vomeronasal receptor neurons and glands contain terminal alpha-D-galactose and beta-N-acetyl-D-galactosamine sugar residues that are not expressed by analogous cells in the olfactory mucosa and septal organ.

Acetylgalactosamine↗
PubMed1992

Ibuprofen augments bradykinin-induced glycoconjugate secretion by human nasal mucosa in vivo.

Bradykinin (BK) stimulates vascular permeability and glycoconjugate secretion in human nasal mucosa. Since some of the effects of BK may be mediated by autocrine generation of arachidonic acid metabolites, the influence of ibuprofen, a cyclooxygenase inhibitor, on BK-induced nasal secretion was studied. Six normal male subjects had nasal provocations with 0, 10, 100, and 1000 nmol of BK before and after treatment with 400 mg of ibuprofen. Secretions were collected by nasal lavage. Total protein (marker of protein secretion), glycoconjugate (mucous cell marker), lysozyme (serous cell marker), and albumin (marker of vascular permeability) were measured. Basal glycoconjugate secretion was higher after ibuprofen (219 +/- 32 micrograms/ml) than before (81 +/- 56 micrograms/ml; p less than 0.05 by analysis of variance). BK stimulated significant, dose-dependent albumin, total protein, and glycoconjugate secretion. Lysozyme secretion was not stimulated. BK (1000 nmol) significantly increased total protein secretion, tenfold to twentyfold, and albumin secretion by 40-fold to 60-fold. Ibuprofen did not alter BK-induced total protein or albumin secretion. Glycoconjugate secretion after ibuprofen treatment was significantly higher than normal at 10 nmol (p less than 0.05), 100 nmol (p less than 0.02), and 1000 nmol of BK (519 micrograms/ml +/- 74 versus 213 +/- 15 micrograms/ml; p less than 0.05). Therefore, BK induces vascular permeability and exocytosis from glycoconjugate-containing cells but does not stimulate serous cells. Ibuprofen increases baseline secretion of glycoconjugate and enhances BK-induced glycoconjugate secretion. Ibuprofen does not alter BK-induced vascular permeability.

Adult↗
PubMed2005

Histochemical analysis of glycoconjugate secretion in the alimentary canal of Anguilla anguilla L.

Conventional histochemical methods as well as lectin-binding techniques were used to study glycoconjugates that are present in the alimentary canal of the European eel (Anguilla anguilla). Specimens from pharynx, oesophagus, stomach and intestine were collected from adult ("silver eel" stage) females. Alcian Blue pH 2.5/PAS and High Iron Diamine/Alcian Blue pH 2.5 reactions were performed to stain neutral and acidic glycoconjugates. In addition, lectin histochemistry was applied to identify acidic glycoconjugates containing O-acylated sialic acids. Finally, the presence of sugar residues in the oligosaccharide side chains of glycoconjugates were investigated by using biotinylated lectins. Acidic and neutral glycoconjugates were found to be secreted throughout the alimentary canal, the acidic glycoconjugates appeared to be either sialylated or sulphated. Sialylated glycoconjugates were identified to contain sialic acid substituted at carbon in position 7 (C7). Sulphated glycoconjugates were particularly abundant in the distal intestine and were not present in the secretory products of the gastric mucosa, which contained a variety of sugar residues (D-N-acetyl-galactosamine, beta-D-galactose, alpha-D-mannose, alpha-L-fucose, D-N-acetyl-glucosamine). Lectin binding was observed in mucous cells of pharynx, oesophagus and intestine, and particularly some monosaccharides (D-N-acetyl-galactosamine and beta-D-galactose) were abundantly present.

Animals↗
PubMed1997

Insulin stimulates production of glycoconjugate layers on the cell surface of gastric surface mucous cell line GSM06.

The mechanism of regulation of mucus production in the gastric mucosa remains unclear. Recently, we established a gastric surface mucous cell line GSM06, which produces periodic acid-Shiff (PAS)-positive glycoconjugate (mucus) layers on the cell surface, from transgenic mice harboring a temperature-sensitive simian virus 40 large T-antigen gene. In this study, GSM06 cells were examined for its production of PAS-positive glycoconjugate layers to acid secretagogues and growth factors. The cells were cultured at nonpermissive temperature (39 degrees C) for 3-18 days and stained with PAS. Insulin (1-30 microg/ml; 0.29-8.6 microM) time- and dose-dependently increased production of glycoconjugates on the cell surface. When glycoconjugate layers produced by stimulation of insulin (3-30 microg/ml; 0.86-8.6 microM) were removed from the cell surface of GSM06 cells by a mild trypsin treatment, PAS-positive materials were remarkably decreased (day 18). In addition, morphological findings indicate that a high concentration of insulin (30 microg/ml; 8.6 microM) produced thick PAS-positive glycoconjugate layers just like normal gastric surface mucosa on the cell surface on day 18. In contrast, histamine (0.1-100 microM), carbachol (0.1-100 microM), gastrin-17 (0.1-100 nM), epidermal growth factor (0.01-10 ng/ ml; 1.7-1,700 pM), transforming growth factor-alpha (0.01-10 ng/ml; 1.8-1,800 pM), and fetal bovine serum (1-10%) did not increase glycoconjugate production. These findings suggest that insulin is a stimulator of glycoconjugate production, and stimulates production of glycoconjugate layers on the cell surface in the gastric surface mucous cell line GSM06.

Animals↗
PubMed1987

Glycoconjugate expression in normal, metaplastic, and neoplastic human upper gastrointestinal mucosa.

Glycoconjugate structure in upper gastrointestinal epithelium was studied using five lectins to determine the relationship between aberrant differentiation and glycoconjugate expression. Specimens of normal esophagus, stomach, and duodenum were examined and compared with specimens of columnar metaplasia in the esophagus (Barrett's esophagus) and specimens of adenocarcinoma of the esophagus and stomach. Specific terminal glycoconjugate structures were found for the esophagus, stomach, and duodenum. Minor differences were found between the antral and fundic gland mucosae, reflecting their respective cell populations. In biopsies of Barrett's esophagus, gastric-type columnar metaplasia expressed glycoconjugates indistinguishable from those in the normal stomach. In specialized-type columnar metaplasia, a more restricted expression of glycoconjugates was seen resembling the normal duodenum. The presence of low grade dysplasia in Barrett's esophagus associated with adenocarcinoma had no impact on glycoconjugate expression. However, a distinctive difference in glycosylation was seen in high grade dysplasia of the columnar-lined esophagus and in adenocarcinoma of the esophagus and stomach. Barrett's esophagus is a morphological mosaic in which the glycoconjugate expression resembles that seen in the normal stomach and duodenum. However, in high grade dysplasia and carcinoma, variable deletion of glycoconjugate expression can be found.

Adenocarcinoma↗
PubMed1989

Synthesis and release of glycoconjugates in vitro by human ovarian carcinoma cells isolated from effusions.

Human ovarian carcinoma cells were isolated as multicellular aggregates from patient effusions. Freshly isolated cells were incubated with radioactive glycoconjugate precursors and the glycoconjugates released to culture medium were analyzed. The glycoconjugates appeared to contain both O- and N-linked oligosaccharides. Both fucosylation and sialylation of glycoconjugates occurred. The results of SDS-PAGE analysis showed the presence of a very heterogeneous array of glycoconjugates with no discrete components resolved. The results of glycoconjugate analyses were independent of carcinoma histology, differentiation, progression, and patient chemotherapy. In contrast, mesothelial cells synthesized a major glycoconjugate of molecular mass 65 KDa. The heterogeneous array of carcinoma-derived glycoconjugates may be transformation-related and may have utility in tumor diagnosis and prognosis.

Carbon Radioisotopes↗
PubMed1991

Changes of glycoconjugate contents of the zona pellucida during oocyte growth and development in the golden hamster: a quantitative cytochemical study.

We demonstrated here with the high resolution lectin-gold approach and quantitative analysis, changes of glycoconjugates in the hamster zona pellucida (ZP) during oocyte growth and development in the ovary and the oviduct. Glycoconjugates which contain N-acetyl-D-galactosamine as terminal sugar residues are absent in the ovary but are secreted by secretory cells in the oviduct and are added to the ZP of superovulated oocytes during oviductal transit. Glycoconjugates which carry sialic acid as terminal sugar residues appear to be acquired mainly from the ovary. The oviduct contributes little of this particular component to the ZP during the transit of oocytes in the oviduct. On the contrary D-galactose and N-acetylglucosamine associated glycoconjugates, added to the ZP in ovarian follicles, are also secreted by non-ciliated oviductal epithelial cells and these secretory products are transferred to the ZP in significant amount during passage of the oocyte through the oviduct. Lectin-gold labeling of the ZP of superovulated oocytes reveals homogeneous distribution of gold particles throughout the zona matrix. Thus, we conclude that the ZP of hamster superovulated oocytes consists of glycoconjugates that may derive from different origins. Deposition of ZP glycocomponents begins in the ovary. Similar and new glycoconjugates, secreted by oviductal non-ciliated secretory cells, are added to the ZP of oocytes during oviductal transit. At this stage the ZP is made up of a homogeneous matrix of glycoconjugates.

Animals↗
PubMed1995

Use of glycoconjugates for trypanosomatid taxonomy.

Glycoconjugates from five trypanosomatid genera--Crithidia, Herpetomonas, Endotrypanum, Leishmania, and Trypanosoma--were extracted with Triton X-114 and analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis followed by periodic acid-Schiff staining. Most of the glycoconjugates were detected in the hydrophobic phase, indicating the presence of anchored glycoconjugates. All the trypanosomatids expressed a glycoconjugate with a low molecular weight (below 20 kDa) in this phase. In each species, however, a characteristic and specific pattern of glycoconjugates was also observed in both phases. In the hydrophobic phase: 14-29 kDa glycoconjugates in C. guilhermei; 24-70 kDa in C. fasciculata, C. luciliae, E. schaudinni, and T. cruzi Y and G strains; 45-66 kDa in C. oncopelti and H. samuelpessoai; above 36 kDa in T. dionisii; 20-24 kDa, 36-45 kDa, and 70 kDa in L. tarentolae and T. mega. In the hydrophilic phase, typical glycoproteins were observed in some trypanosomatids: 60 kDa in T. mega and T. cruzi Y strain; 70 kDa in H. samuelpessoai; 66 kDa in C. oncopelti; 20-70 kDa in C. luciliae. These findings suggest that Triton X-114-extracted glycoconjugates could be useful markers for trypanosomatid taxonomy.

Animals↗
PubMedDate not supplied

Chemoenzymatic synthesis and antibody detection of DNA glycoconjugates.

A chemoenzymatic approach for the efficient synthesis of DNA-carbohydrate conjugates was developed and applied to an antibody-based strategy for the detection of DNA glycoconjugates. A phosphoramidite derivative of N-acetylglucosamine (GlcNAc) was synthesized and utilized to attach GlcNAc sugars to the 5'-terminus of DNA oligonucleotides by solid-phase DNA synthesis. The resulting GlcNAc-DNA conjugates were used as substrates for glycosyl transferase enzymes to synthesize DNA glycoconjugates. Treatment of GlcNAc-DNA with beta-1,4-galactosyl transferase (GalT) and UDP-Gal produced N-acetyllactosamine-modified DNA (LacNAc-DNA), which could be converted quantitatively to the trisaccharide Lewis X (LeX)-DNA conjugate by alpha-1,3-fucosyltransferase VI (FucT) and GDP-Fuc. The facile enzymatic synthesis of LeX-DNA from GlcNAc-DNA also was accomplished in a one-pot reaction by the combined action of GalT and FucT. The resulting glycoconjugates were characterized by gel electrophoresis, matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), and glycosidase digestion experiments. Covalent modification of the 5'-terminus of DNA with carbohydrates did not interfere with the ability of DNA glycoconjugates to hybridize with complementary DNA, as indicated by UV thermal denaturation analysis. The trisaccharide DNA glycoconjugate, LeX-DNA, was detected by a dual DNA hybridization/monoclonal antibody (mAb) detection protocol ("Southwestern"): membrane-immobilized LeX-DNA was visualized by Southern detection with a radiolabeled complementary DNA probe and by Western chemiluminescence detection with a mAb specific for the LeX antigen. The efficient chemoenzymatic synthesis of DNA glycoconjugates and the Southwestern detection protocol may facilitate the application of glycosylated DNA to cellular targeting and DNA glycoconjugate detection strategies.

Acetylglucosamine↗
PubMed2001

Design and optimization of 20-O-linked camptothecin glycoconjugates as anticancer agents.

To improve the biological profile of 20(S)-camptothecin, a novel class of 20-O-linked camptothecin glycoconjugates has been designed for preferential cellular uptake into tumor cells by an active transport mechanism. Such conjugates have been optimized for enhanced solubility, stabilization of the camptothecin lactone ring, sufficient hydrolytic and proteolytic stability, and for an overall improvement in tumor selectivity. The constitution of the peptide spacer has a major impact on stability and biological activity of the conjugates both in vitro and in vivo. Glycoconjugates 17-22 with valine residues at the linkage position to camptothecin are sufficiently stable and show good antitumor activity in vitro against HT29 and other tumor cell lines. Fluorescence microscopy and flow cytometry experiments indicate that glycoconjugates such as 19 are taken up into lysosomal compartments of the tumor cell line HT29 by an active transport mechanism. The steric configuration of the particular amino acid residues linked to the camptothecin moiety has a major impact on the in vivo activity of the corresponding glycoconjugates in the breast cancer xenograft MX-1 model. Inhibiting tumor growth by >96%, the glycoconjugates 19 and 21 show the best activity in this particular model and have been investigated more extensively. The glycoconjugate 19 compares favorably to topotecan 4 and glycoconjugate 21 with respect to toxicity against hematopoietic stem cells and hepatocytes. Based on its profile, 19 has been selected for clinical trials.

Animals↗
PubMed1992

Malaria sporozoites and circumsporozoite proteins bind specifically to sulfated glycoconjugates.

Circumsporozoite (CS) proteins, which densely coat malaria (Plasmodia) sporozoites, contain an amino acid sequence that is homologous to segments in other proteins which bind specifically to sulfated glycoconjugates. The presence of this homology suggests that sporozoites and CS proteins may also bind sulfated glycoconjugates. To test this hypothesis, recombinant P. yoelii CS protein was examined for binding to sulfated glycoconjugate-Sepharoses. CS protein bound avidly to heparin-, fucoidan-, and dextran sulfate-Sepharose, but bound comparatively poorly to chondroitin sulfate A- or C-Sepharose. CS protein also bound with significantly lower affinity to a heparan sulfate biosynthesis-deficient mutant cell line compared with the wild-type line, consistent with the possibility that the protein also binds to sulfated glycoconjugates on the surfaces of cells. This possibility is consistent with the observation that CS protein binding to hepatocytes, cells invaded by sporozoites during the primary stage of malaria infection, was inhibited by fucoidan, pentosan polysulfate, and heparin. The effects of sulfated glycoconjugates on sporozoite infectivity were also determined. P. berghei sporozoites bound specifically to sulfatide (galactosyl[3-sulfate]beta 1-1ceramide), but not to comparable levels of cholesterol-3-sulfate, or several examples of neutral glycosphingolipids, gangliosides, or phospholipids. Sporozoite invasion into hepatocytes was inhibited by fucoidan, heparin, and dextran sulfate, paralleling the observed binding of CS protein to the corresponding Sepharose derivatives. These sulfated glycoconjugates blocked invasion by inhibiting an event occurring within 3 h of combining sporozoites and hepatocytes. Sporozoite infectivity in mice was significantly inhibited by dextran sulfate 500,000 and fucoidan. Taken together, these data indicate that CS proteins bind selectively to certain sulfated glycoconjugates, that sporozoite infectivity can be inhibited by such compounds, and that invasion of host hepatocytes by sporozoites may involve interactions with these types of compounds.

Amino Acid Sequence↗
PubMed1994

Phosphorylation of vimentin is an intermediate step in protein kinase C-mediated glycoconjugate secretion.

We have previously shown that fibroblasts from patients with cystic fibrosis (CF) display a higher response to 4 beta-phorbol 12-myristate 13-acetate (PMA) than control fibroblasts for stimulation of both protein kinase C (PKC) cytosol-to-membrane translocation and glycoconjugate secretion. In this study we took advantage of these cells with differential responsiveness to PMA to investigate the endogenous substrate(s) involved in PKC stimulation of glycoconjugate secretion after verification of cystic fibrosis transmembrane conductance regulator gene expression in control and CF fibroblasts. We show that a 57-kDa protein that was associated with cytoskeleton and was identified as vimentin by immunoblotting emerged as a good candidate for mediating PKC stimulation of glycoconjugate secretion. 1) Its phosphorylation by PMA was abolished by PKC inhibition or depletion. 2) In both control and CF fibroblasts, the PMA-induced increase in its phosphorylation preceded the phorbol ester stimulation of glycoconjugate secretion. 3) For both processes, the concentration-response curves were superimposable, with higher maximal levels for CF fibroblasts relative to controls. 4) PMA-stimulated 57-kDa protein phosphorylation, like PMA-stimulated glycoconjugate secretion, was significantly increased by Ca2+. 5) Increased PMA phosphorylation of the 57-kDa protein as a result of okadaic acid inhibition of intracellular phosphatases was reflected in increased PMA stimulation of glycoconjugate secretion. In conclusion, 1) PMA phosphorylation of a cytoskeletal 57-kDa protein, identified as vimentin, appears to be an intermediate step in PKC stimulation of constitutive glycoconjugate secretion in human skin fibroblasts; and 2) this process is impaired in CF disease.

Base Sequence↗
PubMed1998

Gut glycoconjugates in Sparus aurata L. (Pisces, Teleostei). A comparative histochemical study in larval and adult ages.

This study examined the gut of the euryaline fish Sparus aurata, from the pharynx to the rectum. The specimens were collected from adult animals, both sexes, and several larval and juvenile stages, from 4 to 135 days of age. Histochemical methods of distinguish neutral and acidic glycoconjugates, as well as specific techniques to identify acidic glycoconjugates which contained O-acylated sialic acids were used. The presence and distribution of sugar residues in the oligosaccharide side chain of glycoconjugates were investigated with the use of biotinylated lectins. The pharynx and oesophagus of adult fishes showed the presence of abundant secretory cells which synthesized a large quantity of neutral, as well as sulphated and sialylated glycoconjugates, with different cellular combinations of them in the proximal and distal tract. This may be related to the complex functions carried out by this end of the gut in a marine euryaline fish. Epithelial secretory cells were found in the developing oesophagus during larval life (14 days) earlier than in the stomach and intestine (34 days). The simple columnar epithelium that lined the gastric mucosa of adult fish synthesized a mixture of neutral and acidic glycoconjugates, whereas during larval life it was shown to contain neutral glycoconjugates only. The intestinal goblet cells were shown to secrete both neutral and acidic glycoconjugates, especially sulphated forms. The adherent mucus gel of the gastric and intestinal mucosa contained many sugar residues, as revealed by lectin histochemistry. This work clearly demonstrates that the quality of gut mucosubstances varies in different ages and in regions of the fish alimentary canal. This is possibly caused by changes in environmental conditions and may in turn sustain functional alterations of the digestive apparatus.

Animals↗
PubMed1987

Dog tracheal epithelial cells in culture synthesize sulfated macromolecular glycoconjugates and release them from the cell surface upon exposure to extracellular proteinases.

To determine whether glycoconjugates can be released into airways by surface epithelial cells that do not contain secretory granules and, if so, whether extracellular proteinases can affect this release, we studied dog tracheal epithelial cells after 8-10 days in culture. Ultrastructurally, these cells showed an extensive cell surface coat and no secretory granules. Cells were pulse labeled with radioactive sulfate (Na2 35SO4, 50 microCi/ml/24 h) and washed free of the unbound label. Release of sulfated products was then measured at 20-min intervals under basal conditions and again after 20 min of incubation with various extracellular proteinase. We found that these cells synthesized sulfated products and released them spontaneously and continuously into the medium. In addition, trypsin, Pseudomonas aeruginosa elastase, thermolysin, Staphylococcus aureus proteinase, mast cell chymase, plasmin, and kallikrein (each at 10(-7) M except plasmin, at 5 X 10(-6) M) increased the release of sulfated products to 77-667% over baseline release (p less than 0.01, n = 5 dogs for each); preliminary results showed that human neutrophil elastase was also very potent. The sulfated products released by trypsin had an apparent molecular weight of greater than or equal to 10(6) da as determined by gel filtration on Sepharose Cl-4B. Over 50% of these 35S-labeled products were digested to low-molecular-weight products (500-2000 da) upon incubation with endo-beta-galactosidase or with keratanase, suggesting that they are glycoconjugates containing poly(N-acetyllactosamine)-type carbohydrate chains. Decrease in cell staining by lectins specific for poly(N-acetyllactosamine), which accompanied the release of glycoconjugates, indicates that these sulfated glycoconjugates were released by proteinases from the apical cell surface. We conclude that cultured tracheal epithelial cells synthesize and transport sulfated macromolecular glycoconjugates to apical cell surfaces. These glycoconjugates are released from cell surfaces when exposed to extracellular proteinases. We therefore suggest that macromolecular glycoconjugates in airway secretions can originate not only from secretory granules but also from epithelial cell surfaces during airway inflammation.

Animals↗
PubMed1993

A histochemical study on glycoconjugates in epithelial cells in the distal colonic mucosa of adult and developing mice.

Glycoconjugates were histochemically studied in the distal colon of developing ICR mice in view of the presence of goblet and vacuolated cells. Alcian blue, high iron diamine and periodic acid-Schiff stainings were performed to characterize glycoconjugates. In addition, two lectins, Ulex europeus agglutinin I and Limax flavus agglutinin, were applied to detect fucosyl and sialyl residues, respectively. The reactivities to these stainings, noted from day 18 of gestation, did not seem to undergo any major change throughout their development. The present results suggest that: 1) goblet cells secrete sulfated glycoconjugates containing fucosyl and sialyl residues as terminal sugars; 2) vacuolated cells have glycoconjugates containing sialyl residues but no or few fucosyl residues nor sulfonic groups, and certain sialyl residues in the glycoconjugates are probably O-acetylated or O-acylated at least in part; and 3) the brush border of absorptive cells contains glycoconjugates sialylated and fucosylated to same extent but rarely sulfated. Since glycoconjugates elaborated by goblet and vacuolated cells differ from each other, one should be fully aware of the presence of these two types of mucin-producing cells in the distal colon.

Animals↗
PubMed1999

Comparative study of glycoconjugates of the rat prostatic lobes by lectin histochemistry.

BACKGROUND: The rat prostate gland is composed of several distinct lobes: the ventral, lateral, dorsal, and anterior (also called the coagulating gland). Each prostatic lobe is different in its morphology, secretions, and response to hormones. METHODS: The present study characterized and compared the expression of glycoconjugates in three different lobes (ventral, lateral, and dorsal) of the Noble rat prostate gland by lectin histochemistry, using a battery of 30 different lectins. RESULTS: The results indicate that different prostatic lobes elaborate and secrete different glycoconjugates. The dorsal prostatic epithelium secretes mainly in an apocrine mode, as characterized by the presence of apical cytoplasmic blebs which are absent in the other two lobes, though merocrine secretion is also suggested. These cytoplasmic blebs were rich in Man, GlcNAc, Gal/GalNac, Fuc, NeuAc(alpha2,6)Gal, and oligosaccharides. Two types of cytoplasmic belbs were also identified according to their lectin bindings: blebs stained by S-Con A, LCA, PWA, UEA-II, RCA-I, DBA, ECA, WFA, Jacalin, MPA, SJA, LTA, UEA-I, PHA-E, and PHA-L, and some blebs stained by S-WGA, SBA, HAA, HPA, VAA, BPA, MAA, and SNA. The lectins, which reacted with the second type of blebs, also revealed some cytoplasmic granules in the dorsal prostatic epithelial cells. The epithelium of the lateral prostate showed weak or negative reactions to lectins, suggesting that it may express fewer glycoconjugates as compared to the other two lobes. The epithelial Golgi region of the ventral prostate is the most developed among the three lobes, and contained abundant GlcNAc, alpha/beta-GalNAc, and NeuAc(alpha2,6)Gal residues, as shown by its intense reactions to S-WGA, DBA, SBA, HAA, HPA, WFA, and SNA. GS-I-B4 reacted specifically with the basal epithelial cells in all three lobes, indicating that glycoconjugates with terminal alpha-Gal/GalNAc were commonly expressed in these basal cells. The basal cells in ventral prostate might express more complex glycoconjugates, as they were also stained by PWA, RCA-I, ECA, and PHA-L, in addition to GS-I-B4, suggesting that these basal cells contained more Gal(beta1,4)GlcNAc and Gal(beta1,4)GlcNAc(alpha1,2)Man residues. GS-I-B4 and PHA-L also demonstrated a differential staining of the stromal smooth muscles and their associated extracellular matrix in the three prostatic lobes, suggesting that these structural components in different prostatic lobes were different in their complex oligosaccharide contents, which probably has an influence on the epithelial-stromal interaction in the prostate. CONCLUSIONS: In summary, the present study has established for the first time the expression patterns of glycoconjugates in the three lobes of the Noble rat prostate gland and suggests that certain lectins are useful as histochemical markers for the three individual prostatic lobes.

Animals↗
PubMed1992

Morphology and glycoconjugate histochemistry of the palpebral glands of the adult newt, Notophthalmus viridescens.

The eyelids of the newt were studied in 10 microns serial paraffin and 1-2 microns plastic sections using standard histological stains and special stains for glycoconjugates. The eyelids contain four different glands. Simple acinar serous and simple acinar mucous glands occur in the skin; unicellular mucous glands occur in the conjunctiva; and convoluted tubular seromucous glands are present in connective tissue beneath the conjunctiva. The first two are identical to cutaneous glands found elsewhere on the head and body. The simple acinar serous glands are surrounded by myoepithelial cells and release their secretion, which is composed largely of proteins with minimal glycoconjugate content, by a holocrine mechanism. The secretory product of the simple acinar mucous glands is composed of neutral glycoconjugates with a minor content of acidic glycoconjugates; the mucin exhibits strong PAS and PAPD staining and weak staining by AB and PAPS methods. The unicellular conjunctival mucous glands secrete both neutral and acidic glycoconjugates as shown by positive reactions with PAS, PAPD, PAPS, and AB methods. Convoluted tubular seromucous glands in the ventral eyelid synthesize both proteins and neutral glycoconjugates. The mucous secretions of the conjunctival glands probably provide lubrication and protection for the cornea.

Animals↗
PubMed1994

Identification of the lipid moiety and further characterization of the novel lipophosphoglycan-like glycoconjugates of Trichomonas vaginalis and Trichomonas foetus.

The lipid moiety of the lipophosphoglycan (LPG)-like glycoconjugates of Trichomonas vaginalis and Trichomonas foetus, parasites of the urogenital tract of human and cattle, respectively, has been isolated and characterized by a combination of enzymatic and chemical degradation, chromatography, and mass spectrometry. The carbohydrate composition of the glycan inositol lipid core is also reported. The glycan inositol core of trichomonad glycoconjugates is unique in having more than one GlcN and is significantly larger than any other glycan core reported so far. T. vaginalis glycoconjugate binds strongly to the lectin RCA-I, which suggest that the macromolecule possesses terminal beta 1,4-linked galactosyl residues. The binding of T. foetus glycoconjugate to the lectin UEA-I suggests the presence of terminal alpha 1,2-linked fucose. Acid hydrolysis of deaminated and reduced LPG products yields a [3H]anhydromannitol-containing product, indicating the presence of unacetylated glucosamine in the trichomonad LPGs. Reductive radiomethylation has been applied to label free amino groups in the hexosamine or other free amine-containing residues of the trichomonad glycoconjugates. Treatment of the LPGs with phosphatidylinositol-specific phospholipase C from Bacillus thuringiensis liberates a ceramide substituent. Treatment of LPGs with nitrous acid releases a phospholipid moiety containing myo-inositol and ceramide, implying that the LPGs are anchored in the membrane via an inositol-phosphate-ceramide. Structural characterization of the ceramide by gas-liquid chromatography (GC) and GC-mass spectrometry indicated the presence of the major long-chain base sphinganine (d 18: 0 dihydrosphingosine) and a C 16:0 N-acyl group. Lipophosphoglycans from both parasites contain ceramide as their only lipid moiety. These results suggest that T. vaginalis and T. foetus anchor their LPG-like glycoconjugates on the cell surface via inositol-phosphoceramide and also the glycan inositol core of the macromolecule appears to be unique in nature.

Animals↗