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N Gilboa-Garber

Publications and source records attributed to N Gilboa-Garber.

At least 19 recordsLinked to original sources
PubMed1992

Analysis of the amino acid sequence of the Pseudomonas aeruginosa galactophilic PA-I lectin.

Based on the NH2-terminal 30-amino acid sequence of Pseudomonas aeruginosa galactophilic PA-I lectin, two degenerate primer oligonucleotides were synthesized and used in polymerase chain reaction with the bacterial chromosomal DNA as a template. A predominant DNA fragment of the appropriate size was radiolabeled and used as a probe for screening a P. aeruginosa genomic lambda gt11 library. One positive clone carrying an insert of about 630 base pairs encompassing the entire PA-I lectin gene was isolated and found to contain a 369-base pair open reading frame between an initiation codon (19 base pairs downstream from the insertion site, subsequent to a Shine-Dalgarno sequence) and two consecutive stop codons, followed by an oligo (seven) A sequence, in a partial dyad symmetry. The deduced amino acid sequence shows excellent agreement with the quantitative amino acid analysis and a perfect match with the NH2-terminal amino acid sequence of the purified lectin. It reveals that the PA-I lectin subunit contains 121 amino acids (M(r) 12,754; pI 4.94) with a predominant central hydrophilic core between two hydrophobic domains. Secondary structure algorithms predict that it is rich in beta sheets and contains several highly antigenic epitopes, but no signal peptide. In the carboxyl region a potential glycosylation site (Asn-Asn-Ser) was identified. Comparative analyses of this lectin sequence with those of lectins from other sources, reported in the protein and gene data banks, did not reveal any extensive homology.

Adhesins, Bacterial↗
PubMed1992

On the specificity of the D-galactose-binding lectin (PA-I) of Pseudomonas aeruginosa and its strong binding to hydrophobic derivatives of D-galactose and thiogalactose.

The D-galactose-binding lectin (PA-I) from the bacterium Pseudomonas aeruginosa, isolated by affinity chromatography on Sepharose, was examined for its relative affinities for simple sugars and their derivatives using equilibrium dialysis and hemagglutination inhibition tests. The lectin, which was found to bind 0.68 mol of D-galactose per subunit of 12.8 kDa, exhibited an association constant (Ka) of 3.4 x 10(4) M-1 for D-galactose and higher affinities for hydrophobic and thio derivatives of D-galactose (with highest affinity for the hydrophobic thio derivatives). alpha-Methyl-galactoside was a stronger inhibitor than the beta-methyl derivative and alpha-lactose was a weak inhibitor but the hydrophobic phenylated derivatives of the beta-configuration of D-galactose were more potent inhibitors than the respective alpha-galactosides.

Galactose↗
PubMed1991

Antitumoral effects of Pseudomonas aeruginosa lectins on Lewis lung carcinoma cells cultured in vitro without and with murine splenocytes.

Examination of the in vitro effects of PA-I and PA-II lectins of Pseudomonas aeruginosa on Lewis lung carcinoma cells revealed that these lectins differ in their effects. PA-I, the galactophilic lectin, exhibited both cytotoxic and cytostatic activities on these cells (tested by [3H]thymidine incorporation and by crystal violet vital staining). The two activities were dose and time dependent and inhibitable by the addition of methyl-alpha-D-galactoside to the culture medium. PA-II, the L-fucose and D-mannose binding lectin of the same Pseudomonas strain did not exhibit such a direct toxic effect on the tumor cells but affected them in the presence of splenocytes. Its addition to the tumor cells cocultured with murine (C57B1) splenocytes led to a profound cytolysis of the tumor cells, an effect which was inhibited by L-fucose.

Animals↗
PubMed1991

Erythrina lectins detect the H/HI blood groups.

The lectin purified from Erythrina corallodendron seeds which binds N-acetyllactosamine greater than N-acetyl-D-galactosamine greater than alpha and beta galactosides greater than D-galactose was examined for its ABO(H) blood group specificity. It has been shown that this lectin causes the strongest hemagglutination of O(H) and weakest of Oh(Bombay) red blood cells, and interacts with the H antigen in association with the I antigen. The reactions of Erythrina corallodendron and Erythrina indica lectins (which are similar in sugar specificity) with erythrocytes of different ABO(H) and Ii blood groups (the I bloods were all from adults and the i from either cord or adult bloods) revealed the following order of activity: O(H)I greater than A2 I greater than O(H)i adult greater than A2BI greater than BI greater than O(H)i cord greater than A1I greater than A1i adult greater than Bi cord greater than A1BI greater than Ai cord greater than ABi cord greater than OhI. The Erythrina indica lectin showed a lower differentiation between the agglutination of O(H) and Oh erythrocytes. Both Erythrina lectins exhibited H/HI blood group preference but were not inhibited by the saliva from ABO(H) "secretors". Thus they may be classified with the Cytisus sessilifolius, Lotus tetragonolobus and Laburnum alpinum lectins which are inhibited by lactose but not by H blood group substances in secretions.

ABO Blood-Group System↗
PubMed1989

Microbial lectin cofunction with lytic activities as a model for a general basic lectin role.

Lectins are ubiquitous proteins, which exhibit a specific and reversible sugar-binding activity. They react with glycosylated macromolecules and cells and may coaggragate them and lead to their lysis or alterations. Various lectin biological effects are well known, but their basic biological function is considered as yet unknown. In the present review, an experimental evidence and theoretical considerations are forwarded for supporting our suggestion that the general basic lectin or lectinoid (lectin-like protein) function in microorganisms, plants and animals is a cofunction enabling the activities of key lytic enzymes (lysins: glycosidases, proteases, esterases, phosphatases, hemolysin, etc.). The lectin service is: homing onto glycosylated receptors, anchoring to them and induction of cooperative conformational effects which enable their counterpart lysin activity on exogenous or endogenous target molecules and cells. The 'lectin-lysin' pair may reside in the same molecule, or in linked subunits. It may also be formed by cofunction of two separate entities originating from one or two (homogenous or heterogenous) cell sources. The lectin and lysin may be free or cell-bound components located intra or extracellularly. The final result of their cofunction is practically irreversible; either cell and macro-molecule lysis for nutrition, homeostasis and protection or cell alteration, reorganization and new productivity. Our suggestion emphasizes the prominent analogy of lectins to lytic enzyme positioning sites (LEPS), immunoglobulins and polypeptide hormones. The lectin analogy to LEPS and immunoglobulins is exhibited in the lectin-dependent cell and macromolecule lysis for nutritional and homeostatic purposes or for protection, respectively. The hormone-like lectin activity is exhibited in the lectin-dependent cell alterations. In addition to similar functions and effects, the analogy also includes the properties and behavior of these proteins. The suggested hypothesis is based on experimental evidence from microorganisms, plants and animals. It envisions the lectin and lectinoid function in cell attacks on glycosylated molecules or cells, cell-substratum and cell-cell interactions (fusion, invasion, etc.), cell transformation and formation of special structures. All of them according to a developmental program, or special (especially unfavourable) environmental conditions. The lectin resistance to proteolysis and unfavourable pH or temperature is in accord with the suggested hypothesis.

Animals↗
PubMed1988

H blood group detection by the L-fucose binding lectin of the green marine alga Ulva lactuca.

Extracts of the green marine alga Ulva lactuca collected along the seashore of Tel-Aviv exhibit hemagglutinating activity towards papain-treated human erythrocytes. This hemagglutinating activity was shown to be inhibited by L-fucose and EDTA, and to be relatively resistant to heating at 60 degrees C, while sensitive to low pH. Like the lectin of Ulex europeus, the Ulva lectin exhibits blood group H specificity. It agglutinates most strongly erythrocytes of blood group 0(H) followed by B greater than A greater than AB. A2 and A2B erythrocytes are agglutinated by it considerably more strongly than A1 and A1B respectively. Bombay 0(hh) type erythrocytes are almost non-reactive. The lectin can be stored at -20 degrees C for years.

ABO Blood-Group System↗
PubMed1988

Pseudomonas aeruginosa lectins as a model for lectin production, properties, applications and functions.

Pseudomonas aeruginosa is one of the most troublesome human pathogens in the antibiotic consuming era. It produces lectins and lectinoid adhesins as secondary metabolites. The production of these compounds is genetically determined and is highly sensitive to changing environmental conditions. These dictate the type of the lectin produced ["type" variation], the lectin level ["on-off" variation], and its localization ["in-out" variation]. PA-I [galactophilic] and PA-II [fucose and mannose-binding] P. aeruginosa lectins are sensitive to EDTA and exhibit biophysical properties, resembling those of classical plant lectins. They exert similar in vitro biological effects and have an equal applicative potential. Lectin deficient strains and mutants of P. aeruginosa may be used for studies on lectin role in "conditioning" the bacterium lytic and toxic activities in its attacks on cells or macromolecules. The Pseudomonas lectins confunction with lytic and toxic activities: We suggest that they serve the homing and "condition" the lytic enzyme optimal activity on cellular and macromolecular targets. Namely their role resembles that of "positioning sites" of lytic enzymes and "receptor-binding" domains of powerful microbial, plant and animal toxic or lytic systems [including immunoglobulins, which "condition" the lytic activities of complement and phagocytes], as well as certain hormones, which condition limited key lytic activities, and thereby trigger a cascade of metabolic reactions.

Animals↗
PubMed1988

A new lectin-gold complex for ultrastructural localization of galacturonic acids.

We report the development of a cytochemical affinity technique for detection of galacturonic acids at the ultrastructural level. The highly purified gonad lectin from Aplysia depilans (AGL) was tagged with colloidal gold particles and used for labeling carbohydrates in resin-embedded sections of various plant and fungal tissues. Patterns of AGL binding sites were compared to those obtained with a D-galactose-specific lectin, Ricinus communis agglutinin I. Differences in labeling patterns were noted, indicating that the lectins exhibited differential carbohydrate binding. In addition, the considerable loss of labeling over isolated wheat coleoptile walls treated for removal of pectin, after incubation with the AGL-gold complex, strongly suggested an affinity of AGL for pectic substances. A series of cytochemical controls, including sugar inhibition tests, has proven the specificity of the technique and the high affinity of AGL towards galacturonic acids. The potential value of this new lectin for ultrastructural studies on cell wall pectic substances in plant biology and pathology is demonstrated.

Candida albicans↗
PubMed1987

PA-II, the L-fucose and D-mannose binding lectin of Pseudomonas aeruginosa stimulates human peripheral lymphocytes and murine splenocytes.

Pseudomonas aeruginosa lectin PA-II agglutinates human peripheral lymphocytes and stimulates mitogenesis (predominantly in T cells), like the plant lectins PHA and Con A. Murine splenocytes are also agglutinated and stimulated by PA-II as by Con A. Sialidase treatment of the human and murine cells enhances their agglutination and augments the stimulation of human lymphocytes at low PA-II concentrations. The PA-II agglutinating and mitogenic effects are specifically inhibited by L-fucose. The bacterial source and the specificity of PA-II for L-fucose are both rare features among the hitherto described mitogenic lectins. However, since this lectin also binds mannose, a mannose-bearing receptor might be involved in its mitogenicity.

Adhesins, Bacterial↗
PubMed1987

Stimulation of human peripheral lymphocytes and induction of interleukin 2 production by a lectin from the gonad of the sea hare, Aplysia fasciata.

The lectin from gonads of the sea hare, Aplysia fasciata, which reacts with D-galacturonic acid and D-galactose derivatives, was purified by affinity chromatography on Sepharose 4B. The purified lectin was shown to stimulate human peripheral blood lymphocytes and to induce interleukin 2 production like PHA. These activities were specifically inhibited by D-galactose and neutralized galacturonic acid (not by glucuronic acid). The rate of lymphocyte proliferation was similar at 72 and 96 hours in culture. The main stimulation was observed in the T lymphocyte population obtained by rosette formation with sheep red blood cells.

Animals↗
PubMed1986

Interaction of lectins from gonads and haemolymph of the sea hare Aplysia with bacteria.

Gonads and haemolymph of two Mediterranean species of Aplysia (A. depilans and A. fasciata) contain lectins. A. depilans gonad lectin is specific for D-galacturonic acid and D-galactosides, while its haemolymph agglutinin binds N-acetylated sugars. A. fasciata gonad lectin is also specific for D-galacturonic acid, but its haemolymph haemagglutinin exhibits heterogenic specificity. Both Aplysia gonad lectin and haemolymph agglutinins interact with bacteria, including certain Escherichia coli strains, Bacillus subtilis, Pseudomonas aeruginosa strains and marine bacteria such as the light producing Vibrio harveyi and Photobacterium leiognathi, as well as marine bacteria cultured from the close environment of Aplysia.

Adsorption↗
PubMed1985

Pseudomonas lectin PA-I detects hybrid product of blood group AB genes in saliva.

Pseudomonas aeruginosa galactophilic lectin PA-I exhibits an outstanding affinity for soluble hybrid oligosaccharide products of human A and B genes in saliva of heterozygous AB individuals. Neither A nor B salivas, nor an artificial mixture of them, inhibit PA-I hemagglutinating activity to the same extent as saliva from heterozygotes. Other lectins examined do not exhibit this property.

ABO Blood-Group System↗
PubMed1985

Purification and characterization of the gonad lectin of Aplysia depilans.

Extracts of gonads and fertilized eggs of Aplysia depilans contain a D-galacturonic and D-galactose-binding lectin. This lectin reacts strongly with rabbit and human erythrocytes independent of ABO blood groups, weakly with dog, mouse, rat, and chick erythrocytes and not at all or very weakly with sheep erythrocytes. Purification of the gonad lectin was easily achieved, with a high yield, by heating to 70 degrees C, precipitation with ammonium sulfate and affinity chromatography on Sepharose 4B. The purified lectin was found to be a glucoprotein of molecular mass around 55-60 kDa; it stimulates mitogenesis of human peripheral lymphocytes.

Animals↗
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↗