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Query: UNIPROT:P06889 (Mol)
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Lectin histochemical studies were performed on paraffin embedded sections of the olfactory system of the eel to identify specific glycoconjugates on the surface of primary olfactory neurons. The olfactory receptors, the olfactory nerve fibres and their terminals in the bulbs were labelled with the lectins (SBA, BSA-I, BSA-I-B4 and DBA) HRP-conjugated or biotinylated. The lectin staining patterns indicate that the membrane of olfactory neurons of the eel had oligosaccharides with alpha-galactose and alpha-N-acetyl-D-galactosamine residues. These findings represent the demonstration of a molecular probe that recognizes specific sets of neurons. The identical histochemical features previously described in the olfactory neurons in amphibians suggest that these carbohydrate moieties might to related to modulation of the cell-cell interactions in the olfactory system of vertebrates.
Cell Mol Biol 1991
PMID:Lectin histochemical study of olfactory neurons in the eel. 205 86

The discovery of jacalin, a group of lectins from jackfruit seeds (Artocarpus heterophyllus), has attracted considerable attention due to its numerous interesting immunological properties as well as its usefulness in the isolation of various serum proteins. We have further identified a similar lectin from the seeds of Champedak (Artocarpus integer) which we refer to as lectin-C and performed comparative studies with two types of jacalin isolated from different batches of the Malaysian jackfruit seeds (jacalin-M1 and jacalin-M2). The three purified lectins demonstrated equivalent apparent Mr of about 52,500, each of which comprised of a combination of two types of non-covalently-linked subunits with apparent Mr of approximately 13,300 and 16,000. The lectins demonstrated equal haemagglutinating activity against human erythrocytes of blood groups A, B, AB and O. Our data also demonstrated that lectin-C, jacalin-M1 and jacalin-M2 are similar by selectively precipitating human serum IgA1 and colostral sIgA but not IgA2, IgD, IgG and IgM. When immunoelectrophoresis was performed on normal human sera and reacted with the lectins, single precipitin arcs corresponding to IgA immunoprecipitates were detected with lectin-C and jacalin-MI. Jacalin-M2, however, exhibited two closely associated precipitin arcs. The binding of these lectins with IgA was pronouncedly inhibited in the presence of p-nitrophenyl-beta-D-galactopyranoside, 1-o-methyl-alpha-D-galactopyranoside, D-melibiose, N-acetyl-D-galactosamine and D-galactose. The data therefore provide evidence on the differential specificity of IgA binding lectins isolated from seeds of similar as well as distinct Artocarpus species.
Mol Immunol
PMID:IgA binding lectins isolated from distinct Artocarpus species demonstrate differential specificity. 206 19

Freeze-fracture electron microscopy reveals that intramembrane particles are concentrated in a band encircling the posterior portion of the acrosome of Strongylocentrotus purpuratus sperm. Two colloidal gold labeling methods, label-fracture and replica-staining fracture-flip, were employed to show that the plant lectin wheat germ agglutinin, which recognizes a 210 kDa sperm surface glycoprotein, binds to this localized band of intramembrane particles. Monoclonal antibody J18/2, which also recognizes the 210 kDa surface glycoprotein, shows this localized binding in approximately 20% of the sperm observed in this study. The majority of sperm displayed a uniform distribution of receptor sites for monoclonal antibody J18/2. Since wheat germ agglutinin and monoclonal antibody J18/2 are known to agglutinate Strongylocentrotus purpuratus sperm but not sperm of another sea urchin, Lytechinus pictus, similar determinations were made for the latter species. Lytechinus pictus sperm are not labeled with wheat germ agglutinin and are only sparsely labeled with monoclonal antibody J18/2. The acrosomal localizations of wheat germ agglutinin and monoclonal antibody J18/2 receptors in Strongylocentrotus purpuratus sperm are consistent with the involvement of the 210 kDa surface glycoprotein in an egg jelly-induced sperm acrosome reaction. Low-temperature post-embed labeling of thin sections with wheat germ agglutinin and monoclonal antibody J18/2 show concentrations of label within the acrosomal vesicle of Strongylocentrotus purpuratus sperm, suggesting the presence of an intracellular storage site for the 210 kDa glycoprotein.
Mol Reprod Dev 1991 Apr
PMID:Localization of wheat germ agglutinin and antibody binding sites on the plasma membranes of sea urchin sperm heads as revealed by label-fracture and fracture-flip. 206 84

The administration of lectin concanavalin A (Con A) to in vitro cultures of chick embryo fibroblasts caused dose-dependent changes in cell shape, cytoskeleton network and DNA synthesis. After 6 hrs. even a low doses of Con A produced evident effects in serum-free cultures, whereas higher doses were required to cause alterations in cells cultured in serum-added medium. As the sugar competitor mannoside abolishes the effects, it would seem that the lectin acts by binding to transmembrane receptors and that the fibronectin present in the serum engages the receptors so that they are not available to Con A.
Cell Mol Biol 1990
PMID:Cytoskeletal and DNA synthesis modification by concanavalin A in embryonic fibroblasts maintained in serum-free and serum-added medium. 208 21

The present research investigated the time required for reconstructing normal microtubular pattern and the phenotype of cells after short-term (30 min.) and long-term (24 hrs.) pretreatment with the lectin concanavalin A (Con A). Short-term pretreatment led to the formation of incomplete tubules within 2 and 24 hrs. in cells cultured in 199 medium alone. The addition of serum to the medium reversed the globular phenotype and allowed the formation of normal microtubules, even after prolonged pretreatment with Con A. Whereas long-term Con A treatment provoked a reduction in DNA synthesis in 199 alone, in serum-added 199 the percentage of 3H-thymidine incorporation of treated cells tended to reach that of controls over time.
Cell Mol Biol 1990
PMID:Restoration of a normal phenotype, microtubular pattern and DNA synthesis in embryonic fibroblasts concanavalin A pretreated. 208 22

The dynamic process in rat thymocyte restoration after their destruction by glucocorticoid (GC) administration was examined. Thymus weight and thymocyte count became minimal 4-5 days after the administration. Then the thymus took a course of recovery. Endogenous DNA synthesis in thymocytes, reflecting their proliferation within thymus, decreased for 4 days but began to increase 6-8 days after GC treatment. Thymocyte responsiveness to soybean lectin (SBL), a possible stimulator for T-cell-precursors, showed elevation 4-5 days after the treatment. A marked decrease of lymphocytes in the cortex and unclearness of cortico-medullary junction were observed 2-3 days after GC treatment. Clusters of small lymphoid cells, which possibly contained SBL-responding cells, were found in the subcapsular area 4 days after the treatment and successively, large lymphocytes became visible in the same area. Thereafter, small lymphocytes in the cortical mid and deep zones increased, and cortico-medullary junction was restored. These histological features are discussed from the view of correspondence with the dynamic changes of endogenous DNA synthesis and SBL responsiveness in the thymocytes after GC administration.
Cell Mol Biol 1990
PMID:Rat thymus reconstitution after thymocyte destruction by glucocorticoid treatment--from the view of endogenous DNA synthesis and soybean lectin responsiveness in thymocytes. 208 23

A characteristic property of anhydrotrypsin, i.e., its ability to strongly bind C-terminal arginine, proved to be useful as a tool for specific enrichment of a recombinant protein. An arginine tail was introduced at the C-terminus, for example, of a human beta-galactoside-binding lectin by site-directed mutagenesis. The resulting mutant recombinant lectin, which retained sugar-binding activity as high as the wild-type lectin, became recognizable by anhydrotrypsin. It was adsorbed on an anhydrotrypsin-agarose column and eluted with benzoylglycylarginine. The added arginine tail could be specifically removed by carboxypeptidase B. When E. coli lyzate containing the mutant lectin was applied to the column more than 10-fold enrichment of the mutant lectin was attained. This procedure should be generally applicable and may be advantageous because the addition of a single arginine residue may have minimal effect on the structure and function of the target protein.
J Mol Recognit
PMID:Specific isolation by anhydrotrypsin-agarose chromatography of a recombinant protein tagged with an affinity tail arginine at the C-terminus. 209 87

The structure of the N-linked oligosaccharide of the 85-kDa surface glycoprotein (Tc-85) from the infective trypomastigote form of Trypanosoma cruzi was investigated. Tc-85 metabolically labeled with [14C]glucose was purified by affinity chromatography on wheat germ agglutinin-Sepharose. Binding to the lectin was lost on treatment of Tc-85 with neuraminidase. The N-linked asialo-oligosaccharide was released by endo-beta-N-acetylglucosaminidase F digestion of asialo-Tc-85 and was further analyzed using specific exoglycosidases. [14C]fucose was detected after alpha-L-fucosidase treatment or mild acid hydrolysis. The afucosyl oligosaccharide was 3H-labeled by the galactose oxidase-NaB3H4 method. [3H]Galactose was released by alpha-galactosidase, and only then was beta-galactosidase effective in removing another galactose. The gal(alpha 1-3)gal unit was demonstrated by periodate oxidation studies on the [3H]galactose-labeled asialo-glycoprotein. The presence of gal(alpha 1-3)gal in Tc-85 could be related to the recent finding of elevated antibody levels against this epitope in patients with Chagas' disease.
Mol Biochem Parasitol 1990 Feb
PMID:The N-linked carbohydrate chain of the 85-kilodalton glycoprotein from Trypanosoma cruzi trypomastigotes contains sialyl, fucosyl and galactosyl (alpha 1-3)galactose units. 210 74

A method for assessment of the human sperm acrosome reaction is reported using fluorescein isothiocyanate (FITC)-conjugated Concanavalin A (ConA). The technique involved labelling prefixed spermatozoa, where only those spermatozoa that showed a complete loss of the acrosome bound FITC-ConA to the acrosomal region. Competitive sugar binding studies demonstrated that binding of ConA lectin to the acrosomal area of human spermatozoa was inhibited in the presence of 0.2 M D-mannose. Staining with the supravital stain Hoechst 33258 (H258) concomitantly with FITC-ConA allowed determination of only those spermatozoa that had undergone a true and not degenerative acrosomal loss. Incubation of human spermatozoa with 0, 1, 5, and 25 microM calcium ionophore, A23187, for 60 min demonstrated that changes in acrosomal status due to the different treatment protocols may be determined by the dual-staining method. Electron microscopy studies revealed that gold-conjugated ConA bound specifically to the surface of the inner acrosomal membrane of acrosome-reacted spermatozoa. A significant correlation (r = +.97) between transmission electron microscopy (TEM) and FITC-ConA labelling methods of acrosomal status assessment was achieved. The simple ConA labelling procedure reported here therefore provides a reliable method for quantitation of the physiological acrosome reaction of a population of human spermatozoa.
Mol Reprod Dev 1990 Mar
PMID:Assessment of the human sperm acrosome reaction using concanavalin A lectin. 210 90

Aquous extracts from seeds of Artocarpus altilis (breadfruit) and Artocarpus heterophyllus (jackfruit) were compared by polyacrylamide gel electrophoresis. Two bands of the same size (12 and 15 kD) as the jacalin subunits were the major components in breadfruit seed extract. They strongly reacted with anti-jacalin antibodies by western blotting. The breadfruit lectin displayed the same IgAl and IgD precipitation specificity as jacalin in gel double diffusion experiments. It also stimulated in vitro proliferation of human peripheral blood mononuclear cells. These results suggest that lectins from both species of Artocarpus are very similar.
Mol Immunol 1990 Mar
PMID:Structural and functional similarities of breadfruit seed lectin and jacalin. 211 54


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