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Biomedical subjects

N Gilboa-Garber

Publications and source records attributed to N Gilboa-Garber.

At least 55 records · Page 3Linked to original sources
PubMed1981

A new mitogenic D-galactosephilic lectin isolated from seeds of the coral-tree Erythrina corallodendron. Comparison with Glycine max (soybean) and Pseudomonas aeruginosa lectins.

The lectin of Erythrina corallodendron (Caesalpiniaceae) seeds was purified by heating, ammonium sulfate fractionation, and affinity chromatography on acid-treated Sepharose. The purified lectin is similar to the soybean lectin in being a glycoprotein of molecular weight around 110 000 - 120 000 and having D-galactosephilic activity. This lectin, like the soybean and Pseudomonas aeruginosa lectins, binds to D-galactosamine, N-acetyl-D-galactosamine, alpha- and beta-galactosides as well as to D-galactose. Like these lectins it absorbs onto either untreated or enzyme (papain or neuraminidase) treated human red blood cells, but exhibits a considerable mitogenic activity towards human lymphocytes (predominantly T cells) only after their treatment with neuraminidase. This mitogenic stimulation of lymphocytes is inhibited by D-galactose and its derivatives. Despite the great similarity between them, the E. corallodendron, soybean, and Pseudomonas lectins differ in regard to the intensity of their agglutinating activity towards erythrocytes obtained from different animals and human donors of diverse ABO blood groups. This phenomenon may be attributed to the difference in the affinities of the three lectins to the various D-galactose derivatives and to their molecular properties.

Acetylgalactosamine↗
PubMed1980

Estimation of nonspecific lectin-mediated staining of glutaraldehyde-fixed cells.

Lectin-mediated stainings are widely used for the visualization of carbohydrate-carrying cellular components using the electron microscope. The use of glutaraldehyde-fixed cells for these stainings introduces the possibility of low nonspecific lectin-trapping by the glutaraldehyde which coats the cells. This trapping was estimated by means of peroxidase-binding to human leukocytes. Tetrahymena pyriformis and Escherichia coli cells and was shown to be prevented by rinsing the glutaraldehyde-fixed cells in an amino solution before exposure to the lectin.

Aldehydes↗
PubMed1980

Interactions of pseudomonas aeruginosa hemagglutinins with Euglena gracilis, Chlamydomonas reinhardi, and Tetrahymena pyriformis.

The galactosephilic and mannosephilic hemagglutinins of Pseudomonas aeruginosa adsorbed onto Euglena gracilis, Chlamydomonas reinhardi, and Tetrahymena pyriformis. Furthermore, peroxidase binding to the 3 protozoan species was shown to be mediated by these lectins. Binding of Pseudomonas lectins to E. gracilis and C. reinhardi caused their specific agglutination, whereas no agglutination was observed with T. pyriformis, even after treatment by papain or by NaF. Added to the culture medium, the Pseudomonas hemagglutins stimulated growth of E. gracilis and T. pyriformis due to their binding to these protozoa; this effect was partly inhibited by the specific sugar.

Adsorption↗
PubMed1979

Interaction of the mannosephilic lectins of Pseudomonas aeruginosa with luminous species of marine enterobacteria.

The marine bacteria Beneckea harveyi and Photobacterium leiognathi were shown to bear mannose-containing binding sites for the mannosephilic lectins of Pseudomonas aeruginosa and concanavalin A (Con A). The interaction between the lectins and the marine bacteria was demonstrated by the bacteriagglutination test, by adsorption of the lectins onto the bacteria and by mannose-specific peroxidase-binding to the lectin-coated bacteria. Treatment of the bacteria with formaldehyde, phenol, ethanol or boiling them for 15 min, did not alter their ability to adsorb the lectins. The growth rate of the marine bacteria was unaffected when either the Pseudomonas lectins or Con A was added to the culture medium.

Concanavalin A↗
PubMed1978

Comparative study of the sensitivity of acetylcholinesterases and cholinesterases from animal and bacterial sources to inhibition by serotonin and its derivatives.

Serotonin was found to inhibit human erythrocyte and electric-eel acetylcholinesterase activities. The serotonin amino group, free of negative charges in its vicinity and its hydroxyl group, were important for the inhibition. Serotonin precursors and several related compounds had little or no effect. Human plasma cholinesterase was also inhibited by serotonin and tryptamine. In contrast to these animal enzymes, the cholinesterase of Pseudomonas aeruginosa was refractory to serotonin and its derivatives under the same experimental conditions.

Acetylcholinesterase↗
PubMed1977

Mannose-binding hemagglutinins in extracts of Pseudomonas aeruginosa.

Mannose-binding hemagglutinins were found in the extracts of a pyocyanin-forming Pseudomonas aeruginosa, which contain galactose-specific hemagglutinins. They were purified simultaneously with the latter proteins by heating to 70 degrees C, precipitating with ammonium sulfate, application to a Sepharose 4B column, and elution from it by 0.05 M mannose. The mannose-specific hemagglutinins were shown to be similar to the galactophilic ones in (a) being glycoproteins of very low molecular weight (about 11 000 by SDS gel electrophoresis), (b) their tendency to aggregate, and (c) their ability to effect stronger agglutination of erythrocytes treated with papain than of untreated ones. They were found to resemble them also in their reaction with simple sugars and interactions with divalent cations, which are essential for their activity. In these properties, as well as in their relative resistance to heat and to proteolytic enzymes, these two types of bacterial hemagglutinins are like most of the plant, contrasted with the animal, hemagglutinins. The reactions with mannose and mannose-bearing compounds (yeast mannan, horseradish peroxidase (EC 1.11.1.7), and serum globulins), which are not shared with the galactophilic Pseudomonas hemagglutinins, indicate a relationship of the mannose-binding protein of Pseudomonas to the plant lectin concanavalin A. The mannose-binding hemagglutinins do not exhibit identical cell-agglutinating spectra owing to difference in profiles of sugar specificity and relative affinity to mannose derivatives compared with free mannose.

Agglutinins↗
PubMed1977

Specific agglutination of Escherichia coli O128B12 by the mannose-binding proteins of Pseudomonas aeruginosa.

The mannosephilic haemagglutinins of Pseudomonas aeruginosa were found to agglutinate cells of Escherichia coli O128B12, to be adsorbed onto them and to attach peroxidase to them. These reactions were specifically inhibited by D-mannose. No agglutination by this Pseudomonas haemagglutinin was obtained when several other enteropathogenic types of Escherichia coli and some other Gram-negative bacteria were examined. Concanavalin A, which also reacted with Escherichia coli O128B12 cells, interacted with some of the other bacteria examined, too. Escherichia coli O128B12 was not agglutinated by the Pseudomonas galactosephilic haemagglutinins and those of the plant Phaseolus vulgaris. Its maximal agglutination by the Pseudomonas mannosephilic haemagglutinins was obtained employing cells grown for 4-6 h in conventional media. The growth temperature, aeration and presence of certain amino acids, but not D-mannose, in the culture medium had some effect on the agglutination in tensity; pH 6-8 was optimal for it and only at pH 3.0-3.2 no agglutination was observed. Treatment of the bacteria by proteolytic enzymes, ethanol or formaldehyde did not alter their agglutinability by either the Pseudomonas lectin or by antibodies produced against them in rabbits. Heating of the bacteria to 100 degrees C prevented their agglutination by the Pseudomonas lectin and lowered their ability to adsorb it, but did not significantly affect their reactions with the rabbit antibodies.

Agglutination↗