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Biomedical subjects

J Finne

Publications and source records attributed to J Finne.

At least 73 records · Page 4Linked to original sources
PubMed1984

Structural studies on glycoprotein oligosaccharides of chromaffin granule membranes and dopamine beta-hydroxylase.

Dopamine beta-hydroxylase present in the soluble matrix of bovine adrenal medullary chromaffin granules contains biantennary complex oligosaccharides and high-mannose oligosaccharides in a molar ratio of approximately 2:1. The high-mannose oligosaccharides contain an average of six mannose residues. The largest biantennary oligosaccharides (40% of the total) have two complete peripheral branches consisting of sialic acid-galactose-N-acetylglucosamine, but an equal proportion lack sialic acid on one branch and the remainder lack N-acetylglucosamine and/or galactose. Affinity chromatography on lentil lectin-agarose demonstrated that 84% of the dopamine beta-hydroxylase biantennary oligosaccharides are substituted by fucose on the core N-acetylglucosamine which is linked to asparagine. Based on carbohydrate concentration and the proportions of biantennary and high-mannose oligosaccharides, it would appear that the four dopamine beta-hydroxylase subunits of Mr congruent to 75,000 are not identical with respect to their oligosaccharide moieties. In chromaffin granule membranes, high-mannose and biantennary oligosaccharides comprise 20 and 35%, respectively, of the glycoprotein carbohydrate. Almost 40% is present in the form of large complex oligosaccharides with three or more antennas, less than 3% of which have both a core fucose residue and a 2,6-substituted alpha-linked mannose residue. Chromaffin granule membranes also contain a small proportion (approximately 6%) of O-glycosidically linked glycoprotein oligosaccharides which are predominantly monosialyl derivatives of galactosyl-N-acetylgalactosamine. The ratio of N-acetyl- to N-glycolylneuraminic acid in dopamine beta-hydroxylase and the glycoproteins of chromaffin granule membranes is approximately 1.5:1, which is within the same range as that previously found in membrane gangliosides and in the chromogranins isolated from the soluble granule matrix.

Adrenal Medulla↗
PubMed1984

Specific cell-surface labeling of polyglycosyl chains in human erythrocytes and HL-60 cells using endo-beta-galactosidase and galactosyltransferase.

In order to identify the molecule components carrying polyglycosyl chains on cell surfaces a two-step enzymatic method was developed. In the first step, the cells were incubated with endo-beta-galactosidase to selectively expose terminal N-acetylglucosamine residues of the lactosamine backbone to the chains. In the second step these residues were glycosylated by incubation with galactosyltransferase and radioactive UDP-galactose. As many as 2.5-3.0 X 10(6) residues per cell could be transferred to human erythrocytes. Negligible amounts of labeling occurred if either of the enzymes was omitted from the incubations. Of the label 80% was found in glycoproteins. In accordance with previous observations, bands 3 and 4.5 were found to be the main carriers of polyglycosyl chains. In human promyelotic HL-60 leukemia cells, a major band of apparent molecular weight of 110000-140000 was labeled. In addition, bands of lower molecular weight which appear to have escaped detection by previous methods were also labeled. The novel labeling method was found to be simple to perform, uses commercially available reagents, and leads to the efficient and highly specific labeling of cell surface molecules carrying polyglycosyl chains.

Cell Line↗
PubMed1984

Escherichia coli fimbriae recognizing sialyl galactosides.

Fimbriae recognizing sialyl galactosides (S fimbriae) were purified from an Escherichia coli strain. The S fimbriae were morphologically identical to type 1 and P fimbriae of E. coli and showed a hemagglutination that was abolished when erythrocytes were treated with neuraminidase. Hemagglutination by the purified fimbriae was inhibited by orosomucoid but not by its desialylated derivative. Of the oligosaccharides tested, sialyl-(alpha 2-3)-lactose and sialyl-(alpha 2-3)-N-acetyllactosamine had the strongest inhibitory activities. It was concluded that S fimbriae have the strongest affinity for (alpha 2-3)-linked sialyl galactosides. In the enzyme-linked immunosorbent assay, the hyperimmune serum to the S fimbriae reacted strongly with the homologous antigen but not with type 1, P, or nonhemagglutinating KS71C fimbriae of E. coli. Analogously, the hyperimmune sera to the other E. coli fimbriae did not react with the purified S fimbriae. The immunoprecipitation assay showed that S fimbriae on different E. coli serotypes shared immunological cross-reactivity.

Cross Reactions↗
PubMed1983

Isolation and structural characterization of five major sialyloligosaccharides and a sialylglycopeptide from normal human urine.

Five major sialyloligosaccharides and a sialylglycopeptide have been isolated from normal human urine by charcoal adsorption, gel filtration, ion-exchange chromatography, and paper chromatography. Structural studies including gas-liquid chromatography of monosaccharide and disaccharide derivatives, methylation analysis, glycosidase treatments, and CrO3 oxidation indicated the following structures for the compounds: 1, NeuAc(alpha 2-6)Gal(beta 1-4)Glc; 2, NeuAc(alpha 2-6)Gal(beta 1-4)GlcNAc; 3, NeuAc(alpha 2-3)Gal(beta 1-4)Glc; 4, NeuAc(alpha 2-3)Gal(beta 1-4) GlcNAc; 5, NeuAc(alpha 2-3)Gal(beta 1-3) [Neu-Ac(alpha 2-6)]GalNAc; and 6, NeuAc(alpha 2-3)Gal(beta 1-3) [NeuAc(alpha 2-6)]GalNAc (alpha 1-O)Ser. Compounds 4, 5, and 6 have not been described in a free form before. The presence of compound 5 in urine may suggest that it derives from glycoproteins through a catabolic pathway involving cleavage of the carbohydrate-peptide linkage by an endo-N-acetylgalactosaminidase. The predominating sialyloligosaccharides in urine were compounds 3 and 4. The predominance of the compounds with the sialyl(alpha 2-3) linkage is of interest in view of the recent discovery of uropathogenic Escherichia coli strains with binding specificity for sialyl(alpha 2-3)galactosides.

Adult↗
PubMed1983

Antigenic similarities between brain components and bacteria causing meningitis. Implications for vaccine development and pathogenesis.

Glycopeptides containing polysialic acid units were isolated from human and rat brain and tested for reactivity with antibodies against meningococcal capsules. The polysialosyl glycopeptides bound specifically to horse antiserum against meningococcus group B. The interaction was inhibited by capsular polysaccharides from meningococcus group B but not groups A or C. The capsular polysaccharide of Escherichia coli K1, which is immunochemically similar to the group B polysaccharide, also inhibited binding. These findings could explain the failure to develop efficient vaccines against group B meningococcus or E coli K1 and also suggest that immunological tolerance could be a factor in the pathogenesis of meningitis caused by these bacteria. The presence of the cross-reactive brain component calls for caution in efforts to develop capsular polysaccharide vaccines from these bacteria or the proposed use of passively administered antibodies as immunotherapy of neonatal meningitis.

Animals↗
PubMed1983

Novel cell-binding activity specific for N-acetyl-D-glucosamine in an Escherichia coli strain.

Escherichia coli strains isolated from patients with different levels of urinary tract infection and from healthy persons were tested for their ability to haemagglutinate endo-beta-galactosidase-treated human erythrocytes. Among the 104 strains studied one revealed a strong agglutination reaction with the enzyme-treated erythrocytes. From the monosaccharides tested N-acetyl-D-glucosamine inhibited agglutination most effectively. Orosomucoid and asialo-orosomucoid had no effect on the haemagglutination whereas beta-galactosidase treated asialo-orosomucoid was inhibitory. These findings indicate that the E. coli strain studied contains a novel cell-binding activity with specificity for terminal N-acetyl-D-glucosamine residues.

Acetylglucosamine↗
PubMed1983

Occurrence of alpha 2-8 linked polysialosyl units in a neural cell adhesion molecule.

A brain cell surface protein (BSP-2) was isolated from mice of different ages by affinity chromatography using a monoclonal antibody. Analysis of glycopeptides obtained after pronase digestion revealed that the embryonal and neonatal forms of the antigen contained an unusually high proportion of sialic acid, which decreased during development. Methylation analysis of native and neuraminidase treated glycopeptides indicated that the sialic acid occurred as alpha 2-8 bound polysialosyl units, similar to those of the recently described developmentally regulated polysialosyl glycopeptides of rat brain. Furthermore, the carbohydrate and amino acid composition, and electrophoretic mobility of BSP-2 antigen correspond to those reported for a neural cell adhesion molecule (N-CAM).

Aging↗
PubMed1983

Escherichia coli strains binding neuraminyl alpha 2-3 galactosides.

A total of 46 E. coli strains showing mannose-resistant, P-blood-group independent hemagglutination of human erythrocytes were tested for binding to neuraminic acid. Nine of the strains completely lost their hemagglutination activity after the erythrocytes were treated with neuraminidase. To characterize the receptor structure, different neuraminic acid containing glycoproteins, their desialylated derivatives and neuraminyl oligosaccharides were tested for hemagglutination inhibition. These studies showed that the nine strains had binding specificity for alpha 2-3 linked neuraminic acid.

Carbohydrate Conformation↗
PubMed1983

Enzymic properties of an N-acetylglucosaminide 3-alpha-L-fucosyltransferase of a wheat-germ agglutinin-resistant melanoma clone.

A fucosyltransferase was solubilized by extraction with Triton CF-54 from a wheat-germ agglutinin-resistant variant of mouse B16 melanoma. Through affinity chromatography on GDP hexanolamine--Sepharose a 44-fold enrichment of its specific activity was obtained. Analysis of its specificity indicated that the enzyme is an N-acetylglucosaminide 3-alpha-L-fucosyltransferase, which is able to transfer fucose to oligosaccharides containing Gal(beta 1-4)GlcNAc and Gal(beta 1-4)Glc structures. The enzyme is activated by divalent cations and has a maximum of activity at pH 5. It is unable to transfer fucose to sialylated glycoproteins, 6-alpha-sialyllactose or 3-alpha-sialyllactose. As suggested by its precipitation in the presence of antibodies raised in rabbit against a soluble human milk N-acetylglucosaminide 3-alpha-L-fucosyltransferase, these two enzymes seem to be structurally related.

Agglutination Tests↗
PubMed1983

Cell adhesion mediated by a purified fucosyltransferase.

Human embryonic skin fibroblasts attach and spread on surfaces on which a fucosyltransferase purified from human milk has been immobilized. The adhesion-enhancing effect of the transferase involves specific interactions of the enzyme surface with the cell surface carbohydrate acceptors, as suggested by the following findings. About 80% of human embryonic skin fibroblasts attach and spread in 1 hr on fucosyltransferase surfaces; in contrast, bovine serum albumin, fetuin, asialofetuin, and asialotransferrin surfaces fail to enhance adhesion. The adhesion-mediating activity of the transferase is destroyed by alkylation of the sulfhydryl groups or by heating. The adhesion on fucosyltransferase surfaces is inhibited by glycoprotein, glycolipid, and oligosaccharide acceptors containing the sugar sequence galactosyl-(beta 1 leads to 4)-N-acetylglucosamine, in agreement with the substrate specificity of the enzyme. The results suggest that glycosyltransferases are able to stimulate cell adhesion in a manner similar to that proposed for lectins.

Cell Adhesion↗
PubMed1982

Occurrence of unique polysialosyl carbohydrate units in glycoproteins of developing brain.

A novel type of glycopeptides comprising approximately 10% of the total protein-bound neuraminic acid in developing rat brain have been isolated and characterized. The glycopeptides displayed unique properties including precipitation with cetylpyridinium chloride, strong binding to anion exchange column, and large apparent size in gel filtration. Structural studies including methylation analysis, as well as gel filtration experiments with native and desialylated glycopeptides, suggested that they were composed of a core similar to that of normal tri- and tetraantennary N-glycosidic glycopeptides, with outer branches of the general structure (NeuAc alpha 2-8)nNeuAc alpha 2-3Gal--. The total number of sialic acid residues varied from 8 to at least 12. Similar glycopeptides were not observed in liver or kidney of the young rat or in the brain of the adult animal. These observations suggest that the polysialosylated glycopeptides represent a class of developmentally regulated carbohydrate structures characteristic of developing brain tissue.

Animals↗
PubMed1982

The influence of membrane mutations on metastasis.

In an effort to assess the effect of surface carbohydrates upon the metastasizing properties of tumor cells, lectin-resistant mouse melanoma cells were selected. Wheat-germ-agglutinin-resistant lines displayed mainly decreased metastasis properties as well as well-defined alterations in surface carbohydrates: in a glycopeptide with four side chains, two of them were missing their terminal sialic acid residues while two fucoses were newly attached to the oligosaccharide. The enzymatic defect could be pinpointed to an over-60-fold increase in fucosyltransferase, while the sialyltransferase did not decrease significantly. Revertants were again selected with lectins and their fucosyltransferase activities returned to normal values again. The metastasizing potential of the revertants was not yet assessed carefully but a return of some of the metastasizing potential was noted.

Animals↗
PubMed1982

Enzymatic basis for a lectin-resistant phenotype: increase in a fucosyltransferase in mouse melanoma cells.

In the search for the biochemical basis of the control of glycosylation of cell surface carbohydrates, revertant clones were isolated from previously characterized wheat germ agglutinin-resistant clones of B16 mouse melanoma cells by selection for resistance to Lotus tetragonolobus lectin or to ricin. Comparison of the wheat germ agglutinin-resistant clones with the parent and revertant clones indicated that this phenotype was correlated with an increased sensitivity to the Lotus lectin, a 60- to 70-fold increase in alpha 1 leads to 3 fucosyltransferase activity and a decreased sialic acid content of the N-glycosidic chains of glycoproteins. The results suggest a novel type of control mechanism for lectin resistance, an increase in a glycosyltransferase activity. The presence of alpha 1 leads to 3 bound fucose on N-acetylglucosamine residues would interfere with the addition of sialic acid by alpha 2 leads to 3 linkages to galactose residues in the carbohydrate units, and this change could explain the resistance to wheat germ agglutinin and the increased sensitivity to the Lotus lectin. A change in a regulatory gene for the fucosyltransferase as a possible primary cause for the changed phenotype is discussed.

Animals↗