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 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.     

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.     

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.     

Studies on the interaction of the mistletoe lectin I with carbohydrates

Summary Carbohydrates and modified derivatives of D-galactose have been studied for their capacity to inhibit the hemagglutination of human erythrocytes by mistletoe lectin I. Inhibition data suggest that unmodified hydroxyl groups at the C-2, C-3, and C-4 position of the D-galactopyranosyl ring are essential for binding to the active sites of the lectin.     

A lectin in the pollen of marihuana,Cannabis sativa L.

Summary A lectin was found in the pollen ofCannabis sativa L. which reacted with papain treated erythrocytes. The lectin has an affinity for glucose containing receptor sites.     

Differential properties of two molecular forms of 4-aminobutyrate-2-ketoglutarate transaminase (GABAT) from pig brain (author's transl)]

The two forms isolated exhibit some differences concerning their physicochemical and functional properties. They are identical with the previously purified molecular fomrs, GABAT I and GABAT II, separated by DEAE cellulose chromatography.     

Enhancement of vertebrate cardiogenesis by a lectin from perivitelline fluid of horseshoe crab embryo

Cardiac myocytes are the first cells to differentiate during the development of a vertebrate embryo. A wide variety of molecules take part in various steps in this process. While exploring biologically active molecules from marine sources, we found that a constituent of perivitelline fluid from embryos of the Indian horseshoe crab can enhance growth and differentiation of chick embryonic heart. We have purified the factor and identified the cardiac promoting molecule to be a novel lectin. We show that this molecule influences cardiac development by increasing the number of cells constituting the heart and by modulating the expression of several cardiac development regulatory genes in chick embryos. Using mouse embryonic stem cells we show that the cardiac myocyte-enhancing capacity of this molecule extends to mammals and its effects can be blocked using methylated sugars. This molecule may prove to be an important tool in the study of cardiomyocyte differentiation.     

Oncostatic activity of extracts from Alangium vitiense on murine lymphoid neoplasms]

A total alkaloid and two purified alkaloid extracts of Alangium Vitiense were revealed by our experimental screening to be oncostatic on L1210 leukemia and two other lymphoid neoplasias in Mice. They are not active on myelomonocytoid leukemia WEHI3 nor on B16 melanoma.     

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.     

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

Summary 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.     

Co-localization of galectin-1 with GM1 ganglioside in the course of its clathrin- and raft-dependent endocytosis

Mammalian galectin-1 (Gal-1), a beta-galactoside-binding lectin has a prominent role in regulating cell adhesion, cell growth and immune responses. Downregulation of these biological functions may occur via internalization of Gal-1. In the present study we have investigated the mechanism and possible mediator(s) of Gal-1 endocytosis. We show that internalization occurs at a temperature higher than 22 degrees C in an energy dependent fashion. After one hour incubation Gal-1 localizes in the Golgi system within the cells, and then disappears without accumulation in degradation compartments, such as lysosomes. Based on their strong intracellular co-localization, two glycoconjugates, GM1 ganglioside and CD7 are implicated in the sorting of internalized Gal-1 into Golgi. Other known Gal-1 binding glycoproteins on T cells (CD2, CD3, CD43 and CD45) do not cointernalize with the lectin. Internalization of Gal-1 depends on its lectin activity and follows dual pathways involving clathrin-coated vesicles and raft-dependent endocytosis.     

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     

Binding of ferritin-lectin conjugates to C-type virus in intact cells.

Ferritin-Ricin II and Ferritin-Concanavalin A bound to budding as well as mature C-type viral particles. No differencies in binding between the viral coat and adjacent plasma membrane were detected with either lectin conjugate. Aggregation of viral particles by lectin conjugates was observed, and linking of virus to the plasma membrane resulted in phagocytosis of viral particles.     

Neutrophil extracellular traps in cancer progression

Neutrophils are being increasingly recognized as an important element in tumor progression. They have been shown to exert important effects at nearly every stage of tumor progression with a number of studies demonstrating that their presence is critical to tumor development. Novel aspects of neutrophil biology have recently been elucidated and its contribution to tumorigenesis is only beginning to be appreciated. Neutrophil extracellular traps (NETs) are neutrophil-derived structures composed of DNA decorated with antimicrobial peptides. They have been shown to trap and kill microorganisms, playing a critical role in host defense. However, their contribution to tumor development and metastasis has recently been demonstrated in a number of studies highlighting NETs as a potentially important therapeutic target. Here, studies implicating NETs as facilitators of tumor progression and metastasis are reviewed. In addition, potential mechanisms by which NETs may exert these effects are explored. Finally, the ability to target NETs therapeutically in human neoplastic disease is highlighted.     

Studies on chemically induced tumors in rats: I. Heterogeneity of tumor cells and establishment of syngeneic, tumor-specific cytotoxic T cell clones

Sarcoma P1 was induced in DA rats by DMBA. Anti-P1 antibodies were produced in DA rats, purified via fixed tumor cells and used to induce anti-idiotypic antibodies in syngeneic rats. The anti-idiotypic antibodies were used to generate cytotoxic, P1 specific DA T cells in vitro. These cytotoxic T cells and P1 tumor cells were cloned by limiting dilution. Using the DA anti-P1 specific cytotoxic T cell clones, we were able to characterize 2 types of P1 tumor cell clones, namely those which were susceptible and those which were resistant to the P1 specific cytotoxic T cells. Cytotoxic T cell injected i.v. into syngeneic DA rats could not prevent the development of lethal P1 tumors.     

Side effects of Ricinus lectin (RCA 120) on nucleic acid synthesis in chick embryo fibroblasts

When fibroblasts from chick embryos were treated with Ricinus lectin, the effects observed depended on the stage of development of the embryo from which the cells were prepared. Thus, in 16-day fibroblasts, which have a weak proliferative capacity, nucleic acid synthesis was less sensitive to the effect of this lectin than that in 8-day fibroblasts, whose proliferative capacity is high.     

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

A homogeneous glycoprotein (mol. wt 40,000) containing 34% carbohydrate was isolated from Aloe arborescens var. natalensis. At a concentration of 5 micrograms/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.     

Aplysianin-A, an antibacterial and antineoplastic glycoprotein in the albumen gland of a sea hare, Aplysia kurodai

Aplysianin-A, an antibacterial and antineoplastic factor in the albumen gland of the sea hare Aplysia kurodai, was isolated. It had a molecular weight of approximately 320 kD and consisted of subunits with a molecular weight of 85 kD. It contained 9.8% neutral sugar. Aplysianin A showed 50% inhibition of Bacillus subtilis growth at a concentration of 4 microgram protein/ml and 50% lysis of murine MM46 tumor cells at 14 ng protein/ml. A partial identity of antigenic specificity of the purified specimen with an antineoplastic factor from Aplysia eggs was observed in immunodiffusion tests.