Purification of an L-fucose binding lectin fromUlex europeus by affinity column chromatography

Summary An L-fucose binding lectin fromUlex europeus was purified by affinity column chromatography using an L-fucose-starch complex. The lectin thus purified had a mol.wt of 60,000, and consisted of 2 glycoprotein subunit with mol.wt 29,000 and 31,000, respectively.     

A lectin from the liverwortMarchantia polymorpha L

Bryophytes have been screened for lectins. From the liverwortMarchantia polymorpha (Marchiantiales) a lectin could be purified to homogeneity using a combination of ultrafiltration, size exclusion chromatography and ion exchange chromatography. SDS polyacrylamide gel electrophoresis, size exclusion chromatography and electrospray mass spectroscopy showed that the lectin is a monomeric protein with a M_r of 16,134.64 ± 2.93.Marchantia polymorpha lectin agglutinates erythrocytes of different mammalia and exhibits carbohydrate specifity against complex carbohydrate structures. This is the first report of a lectin isolated from liverworts.This article forms Publication No. 71 of the Arbeitskreis Biologie und Chemie der Moose.     

Isolation and characterization of biologically active lectin from Korean mistletoe, Viscum album var. Coloratum

A mistletoe lectin was isolated from water extracts of Korean mistletoe, a subspecies of Viscum album, grown on Quercus mongolica using CM-Sepharose chromatography followed by an affinity chromatography on a concanavalin A-Sepharose column. The compound proved to be a mistletoe lectin II with D-galactose and N-acetyl-D-galactosamine specificity. Matrix-assisted laser desorption time-of-flight mass spectroscopy showed it to have an average molecular mass of 62.7 kDa and to consist of two subunits of 30.6 kDa and 32.5 kDa. It was a basic protein with isoelectric points of 9.4 and 9.6 by capillary isoelectric focusing and was cytotoxic to Molt4 cell. Received 17 November 1998; received after revision 3 March 1999; accepted 3 March 1999     

Effect of aloe lectin on deoxyribonucleic acid synthesis in baby hamster kidney cells

Summary A homogeneous glycoprotein (mol.wt 40,000) containing 34% carbohydrate was isolated fromAloe arborescens var.natalensis. At a concentration of 5 g/ml, this glycoprotein was shown to stimulate deoxyribonucleic acid (DNA) synthesis in baby hamster kidney (BHK) cells and to have the properties of a lectin which reacts with sheep blood cells. The chemical and physical properties of the glycoprotein (aloe lectin) are also discussed.     

Biochemistry of frog ribonucleases

Frogs have unique pyrimidine base-specific RNases, with structures similar to those of turtle, iguana and chicken RNases. Among the four frog RNases discussed here, three from Rana pipiens, R. catesbeiana and R. japonica oocyte cells show anti-tumour activity, and the latter two show lectin activity towards sialic acid-rich glycoproteins. In this review, (i) we compare their unique primary structures with respect to the locations of their disulphide bridges, three-dimensional structure, base specificity and heat stability as compared with RNase A, and (ii) we summarize current knowledge about the mode of action of lectin and the antitumour activities of the three frog RNases.     

Different precipitin reactions of theAbrus precatorius lectin

Summary Different precipitin reactions of theAbrus precatorius plant lectin with various galactan-polysaccharides are described and compared with a number of other anti-galactose lectins from different sources.     

The lectin fromViscum album L. purification by biospecific affinity chromatography

Summary A lectin fromViscum album which specifically binds to D-galactose was isolated by affinity chromatography on O-lactosyl-, O-galactosyl-polycarylamide or hydrolized sepharose 4 B. Some serological and physicochemical properties of the agglutinin are reported.     

Selective effects of PHA on rat brush border hydrolases along the crypt-villus axis

Summary The mechanism of the toxicity of lectin fromPhaseolus vulgaris seeds has been investigated on rat enterocytes. Cell isolation procedures showed a selectivity in the loss of brush border hydrolases; this indicated that the microvilli blebbing was not the only mechanism of action of lectins on rat enterocytes.     

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

Summary Lectin-mediated stainings are widely used for the visualization of carbohydrate-carrying cellular components using the electron microscope. The use of glutarladehyde-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 andEscherichia coli cells and was shown to be prevented by rinsing the glutaraldehyde-fixed cells in an amino acid solution before exposure to the lectin.     

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

Summary 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.     

Naturally occurring hemagglutinins in the hemolymph of the scorpionParuroctonus mesaensis Stahnke

Summary Lectins which bind sialic acid-containing receptors are present in the hemolymph of the scorpionParuroctonus mesaensis Stahnke. Glycoproteins like bovine submaxillary mucin, fetuin and human orosomucoid behave as strong inhibitors forParuroctonus lectins; desialylation of glycoproteins results in a drastic reduction of their inhibitory capabilities confirming that sialic acids are the terminal monosaccharides ofParuroctonus lectin receptors.We wish to thank Dr H. L. Stahnke, Arizona State University, Tempe, Arizona, for taxonomic assistance. This work received fellowship support from the Consejo Nacional de Investigaciones Cientificas y Técnicas de la República Argentina.     

Platelet aggregation is inhibited by phycolectins

Lectins from four marine algal species were examined for interaction with human platelets. The lectin designated hypnin A, from the red algaHypnea japonica, inhibited adenosine diphosphate (ADP)-or collagen-induced human platelet aggregation in a dose-dependent manner. Complete inhibition was observed at concentrations of 100 and 5 g/ml of the lectin with, ADP (2 M) and collagen (0.2 g/ml)-induced platelet aggregation, respectively. At the inhibitory concentration of 0.5 to 100 g/ml, the lectin did not induce aggregation of resting platelets. Lectins from the other three algal species also inhibited ADP-induced human platelet aggregation. These results indicate that the algal lectins are a new group of inhibitors and may be useful to study glycoconjugates on platelet membranes and to design novel platelet aggregation inhibitors.     

Lectin receptors in snail proteogalactans. II.Archachatina marginata andAchatina achatina (preliminary report)

Summary The lectin receptor sites on the proteogalactans from the albumin glands of West African land snails,Archachatina marginata andAchatina achatina have been studied by precipitin reactions using the agar-gel double diffusion technique with various lectins. The proteogalactans from both snails have predominantly terminal -D-galactose structures; but they show characteristic differences in the topographical features at the surfaces of the carbohydrate structures presumed to be compatible with the combining site for these lectins.     

Differential binding of conA and WGA on the cell surface,the role of sialic acid in their expression and the increased activity of sialidase after cis-Platin treatment

Summary It is reported that concanavalin A (conA) and wheat germ agglutinin (WGA) have a differential binding pattern on normal mouse spleen lymphocytes and the surface of Dalton's lymphoma cells. It is suggested that sialic acid on the cell surface controls the expression of lectin binding sites. Further, it has been observed that the increased release of sialic acid from cell surfaces aftercis-dichlorodiammine platinum (II) (cis-Platin) treatment is due to the increased activity of sialidase.To whom reprint requests should be addressed.     

Isolation of a potent allergen from house dust mite by interaction with the lectin tridacnin

Summary Tridacnin, the lectin from the clamTridacna maxima, precipitates with house dust mite extracts and provides a simple procedure for obtaining a potent, purified mite allergen. Allergenic activity was investigated using the radioallergosorbent test (RAST).We thankKarin Williams, Jill Butler, Elizabeth Quinn andGisela Steinhausen for technical help. This work was supported by the Princess Margaret Children's Medical Research Foundation, the Asthma Foundation of Western Australia, the National Health and Medical Research Council and the Deutsche Forschungsgemeinschaft.     

Additional lectin receptors in galactans from the albumin gland of theAchatina fulica snail

Summary The lectin receptor-site specificity of a purified galactan from snail (Achatina fulica) albumin glands has been studied by precipitin reactions in agar-gel double diffusion experiments with different lectins. Most lectins were found to be specific for terminal -D-galactose structures. Some findings suggest, that the structure DGal13DGal may be one of the receptor sites on the polysaccharide.     

CD23 (the low-affinity IgE receptor) as a C-type lectin: a multidomain and multifunctional molecule

This review, regards the low-affinity receptor CD23 as a C-type lectin and compares it with other C-type lectins and C-type lectin-like receptors. C-type lectins such as the asialoglycoprotein receptor, as well as the dendritic cell immunoreceptor and the dendritic cell-specific intercellular adhesion molecule-3-grabbing nonintegrin on dendritic cell lectin, possess amino acid sequences which interact with Ca⁺⁺ and sugar, and many of them possess an endocytosis signal sequence that includes tyrosine or serine in the cytoplasmic region. In contrast, natural killer receptors lack the Ca⁺⁺ and sugar-binding amino acids but conserve homologous cysteines in the form of C-type lectin, and possess an immunoreceptor tyrosine-based inhibitory motif in the cytoplasmic region which inhibits killer activity when they recognize the self major histocompatibility (MHC) class I molecule. Since human CD23a form has a similar amino acid sequence, the possibility that this sequence is an endocytosis signal or an ITIM is discussed. The function of the reverse RGD and RGD-binding inhibitory peptide in human CD23 from the point of view of the relation between a C-type lectin and MHC class II molecules is also considered. Received 21 May 2001; received after revision 28 November 2001; accepted 29 November 2001     

The amino acid sequence of the agglutinin isolated from the red marine alga Bryothamnion triquetrum defines a novel lectin structure

The primary structure of a lectin isolated from the red alga Bryothamnion triquetrum was established by combination of Edman degradation of sets of overlapping peptides and mass spectrometry. It contains 91 amino acids and two disulphide bonds. The primary structure of the B. triquetrum lectin does not show amino acid sequence similarity with known plant and animal lectin structures. Hence, this protein may be the paradigm of a novel lectin family.     

Disruption of clc-5 leads to a redistribution of annexin A2 and promotes calcium crystal agglomeration in collecting duct epithelial cells

Mutations in CLCN5, which encodes the voltage-dependent Cl⁻/H⁺antiporter, CLC-5, cause Dent’s disease. This disorder is characterized by low molecularweight proteinuria, hypercalciuria, nephrocalcinosis and nephrolithiasis. Using a collecting duct cell model (mIMCD-3) in which endogenous clc-5 is disrupted by antisense clc-5 or overexpression of truncated clc-5, we demonstrate altered expression of the crystal adhesion molecule, annexin A2. Endogenously expressed annexin A2 is intracellular with limited plasma membrane localization. Following clc-5 disruption, there is both a marked increase in plasma membrane annexin A2 and an increase in cell surface crystal retention and agglomeration, which may be attenuated using pretreatment with anti-annexin A2 antibodies or wheat germ agglutinin lectin but not by concanavalin A. We hypothesize that in Dent’s disease, endocytic failure leads to an accumulation at the plasma membrane of crystal-binding molecules that include annexin A2 leading to retention of calcium crystals and ultimately nephrocalcinosis and nephrolithiasis. Received 22 October 2005; received after revision 26 November 2005; accepted 2 December 2005     

Conversion of glycine max seed agglutinins from nonspecific to anti-(A + B).

The seeds of glycine max contain agglutinins which are typically nonspecific in their reactivity. Our investigations show that the phytagglutinins in GM can be converted from nonspecific to anti-(A + B) after the lectin is absorbed with horse red cells. The anti-A and anti-B fractions can be further separated by suitably absorbing the lectin with human red cells. The lectin absorbed with horse red cells or with group-0 human red cells shows an A-stressed activity.