Studies on lectins. XXXVII. Isolation and characterization of the lectin from Jimson-weed seeds (Datura stramonium L.)

The lectin of Jimson-weed seeds (Datura stramonium L.) was isolated by affinity chromatography on a polysaccharide mixture from mycelium of Aspergillus niger. The lectin yields two bands on disc electrophoresis, it has sedimentation coefficient s20,w = 3.8 S and its apparent molecular weight estimated by thin layer gel chromatography is 120,000. The lectin reduced with mercaptoethanol yields on polyacrylamide gel electrophoresis in the presence of dodecyl sulfate three zones corresponding to subunits of molecular weight 72,000, 45,000 and 25,000. The lectin contains large amounts of cystine, glycine, 6.3% of hydroxyproline residues, 4.5% glucosamine and 28% of neutral sugar, predominantly arabinose. The lectin is nonspecific in human erythrocyte ABO system, it is not inhibited by simple sugars but is inhibited by a partial hydrolysate of chitin-containing mixture of polysaccharides from Aspergillus niger.     

Studies on lectins. XXXVIII. Isolation and characterization of the lectin from black locust bark (Robinia pseudacacia L.)

The lectin of black locust (Robinia pseudacacia) bark was isolated by specific adsorption on formaldehyde-fixed human erythrocytes and elution with a borate solution. The lectin is homogeneous on disc electrophoresis and ultracentrifugation (s20,w = 5.8 S) but yields three bands on isoelectric focusing. It has a molecular weight of approximately 110,000 and consists of two types of subunit (mol. wt 29,000 and 31,500). Its pI is approximately 5.9; it contains high amounts of aspartic acid, threonine and serine, no cysteine and very little methionine. Also 7.2% of covalently bound neutral sugar and 0.47% of glucosamine are present. The lectin is nonspecific in agglutination of human erythrocytes, it is inhibited by high concentrations of N-acetyl-D-galactosamine and is mitogenic in rabbit lymph node lymphocytes.     

Studies on lectins: XLIII. Isolation and characterization of the lectin from restharrow boots (Ononis hircina Jacq.)

From 1 kg of dried Ononis hircina Jacq. roots 36 mg of a lectin were isolated by affinity chromatography on O-β-lactosyl polyacrylamide gel. The lectin is homogeneous as judged by ultracentrifugal analysis (s_20,w = 6.2 S), polyacrylamide disc electrophoresis at pH 8.9 or 4.5, gel filtration on thin layers of Sephadex G-200 (M_r = 110 000) and dodecyl sulfate electrophoresis (M_r of sub-units 31 000, both in presence and absence of mercaptoethanol) and disc dodecyl sulfate electrophoresis (pH 9.5). The lectin contains much aspartic and glutamic acids, serine and threonine and also 7.2% of neutral sugar. It is relatively specific for human type O erythrocytes that are agglutinated at a minimal lectin concentration 0.3 μg/ml. The erythroagglutinating activity is not stimulated by Ca²⁺, Zn²⁺, Mg²⁺, Mn²⁺, Co²⁺, or Ni²⁺ salts; it is inhibited most effectively by N-acetyl-D-galactosamineandanumberofD-galactosederivatives. Dissociation constants of several lectin · sugar complexes were estimated by affinity electrophoresis. The lectin is not mitogenic in rabbit lymph nodes lymphocytes.     

Life histories of the powan,Coregonus lavaretus (L.) (Salmonidae,Coregoninae) of Loch Lomond and Loch Eck

Four aspects of the life histories of the two populations of powan Coregonus lavaretus (L.) in Scotland are described: growth (Eck powan are shorter and with greater year to year variance than Lomond); sexual maturation (Eck powan mature younger, but at similar weight to Lomond); spawning (timing in Eck varies, but is consistent in Lomond); and recruitment/mortality (fecundity, sex ratios, and mortality also vary in the short term). Short term differences between the physiological ecology of the populations can be ascribed to the size and topography of the lochs. Long term differences are more difficult to account for, and are more important in that they may signal changes in sustainability. Conservation of powan must be considered in terms of their synecological relationships, not in isolation.     

Fine specificities of two lectins from Cymbosema roseum seeds: a lectin specific for high-mannose oligosaccharides and a lectin specific for blood group H type II trisaccharide

The legume species of Cymbosema roseum of Diocleinae subtribe produce at least two different seed lectins. The present study demonstrates that C. roseum lectin I (CRL I) binds with high affinity to the "core" trimannoside of N-linked oligosaccharides. Cymbosema roseum lectin II (CRL II), on the other hand, binds with high affinity to the blood group H trisaccharide (Fucα1,2Galα1-4GlcNAc-). Thermodynamic and hemagglutination inhibition studies reveal the fine binding specificities of the two lectins. Data obtained with a complete set of monodeoxy analogs of the core trimannoside indicate that CRL I recognizes the 3-, 4- and 6-hydroxyl groups of the α(1,6) Man residue, the 3- and 4-hydroxyl group of the α(1,3) Man residue and the 2- and 4-hydroxyl groups of the central Man residue of the trimannoside. CRL I possesses enhanced affinities for the Man5 oligomannose glycan and a biantennary complex glycan as well as glycoproteins containing high-mannose glycans. On the other hand, CRL II distinguishes the blood group H type II epitope from the Lewis(x), Lewis(y), Lewis(a) and Lewis(b) epitopes. CRL II also distinguishes between blood group H type II and type I trisaccharides. CRL I and CRL II, respectively, possess differences in fine specificities when compared with other reported mannose and fucose recognizing lectins. This is the first report of a mannose-specific lectin (CRL I) and a blood group H type II-specific lectin (CRL II) from seeds of a member of the Diocleinae subtribe.     

Purification and characterization of an anti-(A+B) specific lectin from the mushroom Hygrophorus hypothejus.

A lectin (HHL) was isolated from the fruiting body of the mushroom Hygrophorus hypothejus by a combination of affinity chromatography on stromas of group B erythrocytes embedded in polyacrylamide gel, and DEAE-trisacryl and gel filtration chromatography. Its molecular mass, as determined by gel filtration, is estimated to be 68000 kDa and its structure is tetrameric with four identical subunits assembled with non-covalent bonds. HHL agglutinates specifically A and B blood group erythrocytes and in hemagglutination inhibition assays, exhibits sugar-binding specificity toward lactose, the anomeric alpha form being more effective than the beta form.     

Purification and characterization of a lectin (plant hemagglutinin) with N blood group specificity from Vicia graminea seeds.

A lectin with N blood group specificity was isolated from Vicia graminea seeds. This lectin was purified from a crude extract by precipitation with ammonium sulfate, DEAE-cellulose chromatography and Sephadex G-150 gel filtration. Purification steps were followed by increase of specific activity. Its homogeneity was demonstrated by polyacrylamide gel electrophoresis, immunoelectrophoresis, electrofocusing and ultracentrifugation. This lectin is an acid glycoprotein with 7.3% carbohydrate, a high percentage of serine and contains no sialic acid. The native lectin has a molecular weight about 100 000 and dissociates into four subunits of 25 000 as shown by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Preliminary hemagglutination inhibition has shown that the lectin was not inhibited by any of the monosaccharides contained in N blood group substances; however it was inhibited by the erythrocyte membrane major glycoprotein and the tryptic fragments obtained from erythrocytes.     

Isolation and characterization of a lectin from peanut roots.

A glucose-specific lectin has been purified to apparent homogeneity from 7-day-old peanut (Arachis hypogaea) roots by affinity chromatography on a Sephadex G-50. The lectin has a 66 kDa native molecular mass and a 33 kDa subunit molecular mass as revealed by native and denaturing sodium dodecyl sulphate-polyacrylamide gel electrophoresis, respectively. The purified lectin, gives a single precipitin line with the antiserum produced against 7-day-old root extract and shows 5 bands in the pH range of 4.4-5.4 in the isoelectric focusing gel. The glucose-specific lectin activity in the peanut roots appears from the fourth day onwards. Lipopolysaccharides isolated from the host specific Rhizobium strain are a 68-fold more potent inhibitor of the lectin as compared to glucose.     

New affinity procedure for the isolation and further characterization of the blood group B specific lectin from the red marine alga Ptilota plumosa

The red marine alga Ptilota plumosa has been shownto contain an anti-human blood group B lectin. We report here a new isolationprocedure by affinity chromatography on Sephadex G-200 and characterisation ofthe isolated lectin. The M _r , determined by gelfiltration, was 52,500. SDS-PAGE revealed a single protein band withM _r 17,440, indicating the native lectin was atrimer of subunits with the same M_r, as reported for the lectinsfromtwo other Ptilota species, P.filicinaand P. serrata. Analysis of amino acid composition showedslightly more basic than acidic amino acids. This was in contrast to theP. filicina and P. serrata lectinspreviously found to contain a higher proportion of acidic than basic aminoacids. Haemagglutination inhibition tests showed the P.plumosa lectin was inhibited by galactose, glucose and theirderivatives with p-nitrophenyl--D-galactoside moststrongly inhibitory. All glycoproteins tested failed to inhibit the lectin. Theamino acid composition, human blood group-B specificity and lack of inhibitionby glycoproteins indicate the lectin from P. plumosapossesses unique characteristics among marine algal lectins.     

Isolation and characterization of lectins from kidney beans (Phaseolus vulgaris)

The bioactive properties of lectins obtained from raw and canned red kidney bean (Phaseolus vulgaris) were studied to determine the changes in their bioactivity during the canning process. Phytohaemagglutinin (PHA) was extracted using Affi-gel Blue gel and thyroglobulin-Sepharose and had a molecular weight of 32 kDa. Both the raw and the canned kidney beans possessed the ability to agglutinate red blood cells and inhibit α-glucosidase. The activity found in the canned beans was similar to that from the in the raw kidney beans. However, the amount of lectin that could be extracted from thyroglobulin-Sepharose was much less in the canned samples than in the raw kidney bean samples. The extracted lectin from the raw kidney beans was also subjected to a heating and cooling treatment using a differential scanning calorimeter. The lectin had a nonset denaturation temperature of 77.76 °C and it did not renature upon cooling. In this study, we demonstrated that extracts from raw red kidney bean and canned red kidney bean contain bioactive compounds capable of inhibiting HIV-1 RT in vitro.     

A comparative assessment of temporal variation in diet of powan, Coregonus lavaretus (L.), from Loch Lomond and Loch Eck, Scotland, U.K.

Stomach contents of powan caught throughout the year from Loch Lomond and Loch Eck were examined. Adult powan in Loch Lomond fed mainly on planktonic Cladocera, switching to benthic food during December-April. Bosmina coregoni was the principal planktonic food with Daphnia hyalina an important late summer and autumn prey. Loch Eck powan fed throughout the year on chironomid larvae and Pisidium spp. from the benthos and ingested large amounts of non-food material. Mean dry weights of food in stomachs were correlated with water temperature in Loch Lomond but not in Loch Eck and were higher in powan from Loch Eck over most of the year.     

Isolation and characterization of an N-acetylgalactosamine specific lectin from Salvia sclarea seeds

Crude extracts from Salvia sclarea seeds were known to contain a lectin which specifically agglutinates Tn erythrocytes (Bird, G. W. G., and Wingham, G. (1974) Vox Sang. 26, 163-166). We have purified the lectin to homogeneity by ion-exchange chromatography and affinity chromatography. The agglutinin was found to be a glycoprotein of Mr = 50,000, composed of two identical subunits of Mr = 35,000 linked together by disulfide bonds. The purified lectin agglutinates specifically Tn erythrocytes and, at higher concentrations, also Cad erythrocytes. Native A, B, or O red blood cells are not agglutinated by the lectin and, even after treatment with sialidase or papain, these cells are not recognized. Tn red cells present 1.45 X 10(6) accessible sites to the lectin which binds to these erythrocytes with an association constant of 1.8 X 10(6) M-1. On Cad red cells, 1.73 X 10(6) sites are accessible to the lectin which binds with an association constant of 1.0 X 10(6) M-1. The carbohydrate specificity of the S. sclarea lectin has been determined in detail, using well defined monosaccharide, oligosaccharide, and glycopeptide structures. The lectin was found to be specific for terminal N-acetylgalactosamine (GalNAc) residues. It binds preferentially alpha GalNAc determinants either linked to Ser or Thr (as in Tn structures) or linked in 1-3 to a beta GalNAc or to an unsubstituted beta Gal. Although more weakly, the lectin binds beta GalNAc residues linked in 1-4 to a beta Gal (as in Cad structures). It does not recognize beta GalNAc determinants linked in 1-3 to a Gal (as in globoside) or the alpha GalNAc residues of blood group A structures.     

A blood group A specific lectin from the seeds of Crotalaria striata

A lectin, monospecific for human blood group A red blood cells was extracted from seeds of Crotalaria striata and purified by molecular sieving on Sephadex G-100 and ion-exchange on DEAE-cellulose. A molecular mass of 30 kDa was determined by SDS-polyacrylamide gel electrophoresis under non-reducing and reducing conditions. Molecular sieving on a Superose 12 column indicated a molecular mass of 110 kDa, suggesting the tetrameric nature of the native protein. Amino-acid composition showed the presence of aminated carbohydrate residues on the lectin. N-terminal amino-acid sequencing showed a striking similarity with the N-terminal sequence of the lectin from Crotalaria juncea, which is blood-group non-specific. The potency order of agglutination inhibition with galactose containing monosaccharides was N-acetyl-D-galactosamine greater than D-galactose greater than D-galactosamine as found for blood-group-A-specific lectins from other species.     

Ultrastructure of the retina of two subspecies of Coregonus lavaretus (Teleostei) from Lake Constance (Germany)

In the two studied subspecies of Coregonus lavaretus , the pollan ( C. l. wartmanni ) (which lives deep in the pelagial) and the gangfish ( C. l. macrophthalmus ) (which lives near the slope, closer to the bottom), duplex retinae containing rod and cone photoreceptors are found. Four morphologically different cone types were observed: unequal double cones, short single cones, long single cones and triple cones. The cones are arranged in a square pattern (four double cones around a central short single cone) in the ventral and ventrotemporal and in a row pattern in the nasal and dorsal areas of the retina. Moreover, intermediate patterns can be observed in several regions indicating that double cone twisting occurs, i.e. double cones twist about their longitudinal axis. The highest cone densities are found in the ventrotemporal area. Conversely, the rod photoreceptor density is the highest in the dorsal retina. While the basic morphology of the retina is the same in both subspecies, the distribution of long single and triple cones differs between the studied animals. While these cone types are very rare in the pollan, they are common in the gangfish, though not exhibiting a regular pattern. The findings are discussed with regard to the photic habitat conditions, the systematic position of coregonids and variation of retinal morphology in the two subspecies.