Amount Of Wheat Germ Agglutinin Research Articles

Lectin-Mediated Drug Targeting: Quantification of Binding and Internalization of Wheat germ Agglutinin and Solatium tuberosum Lectin Using Caco-2 and HT-29 Cells

For the potential use of Wheat germ agglutinin (WGA) and Solarium tuberosum lectin (STL) as auxiliary excipients for targeting drugs to colonocytes, the number of Caco-2 and HT-29-bound lectins was determined by fluorimetry using fluorescein-labelled derivatives of the N-acetylglucosamine-specific lectins. After 1 h of incubation, the WGA-binding capacity of 5 × 104 Caco-2 cells was 26.9 ± 0.5 pmol at 4°C and 27.2 ± 1.0 pmol at 37°C respectively. In comparison, 19.5 ±2.9 pmol (37°C) and 16.7 ±0.9 pmol (4°C) WGA were bound within 1 h to 5 × 104 HT-29 cells referring to about 80% of the total amount of WGA bound within 4 h of incubation. In contrast, binding of STL to the colon carcinoma cell lines was independent of incubation times and temperatures tested exhibiting a binding rate of 8.4 ± 0.6 pmol (HT-29) and 9.9 ± 0.8 pmol (Caco-2) STL/ 5 × 104 cells. As determined by flow cytometry, non-specific binding is lower than 1.0% (WGA) and 3.4% (STL). Uptake and intracellular accumulation of the lectins were investigated by confocal laser scanning microscopy at 4°C and 37°C respectively. A decrease of initially membrane-bound lectins concurrent with increasing cytoplasmic enrichment by time was observed by digital cell image analysis. Due to specific and numerically sufficient adhesion as well as internalization, WGA and STL are anticipated as targeting tools in lectin-mediated drug delivery systems.

Lectin histochemistry, ploidy level and proliferation indices in meningioma subtypes

The glycohistochemical expression of binding sites for eight lectins is characterized in a series of 15 meningothelial, 10 fibroblastic and 15 transitional meningiomas. The correlation between lectin staining and either the proliferation index or ploidy level has also been investigated. The data show that the cytochemical binding of some lectins is of value in distinguishing between the different meningioma subgroups. For example, fibroblastic meningiomas express significantly higher amounts of wheat germ agglutinin (WGA) and Ulex europaeus agglutinin (UEA-I) than the meningothelial sub-type. Diploid tumours express a higher glycine maximus (SBA), Arachis hypogaea (PNA) and Phaseolus vulgaris leukoagglutinin (PHA-L) binding than aneuploid tumours. These differences are probably due to the modification of post-transcriptional glycosylation events linked to tumour ageing. The data also reveal that the increased binding of PHA-L is inversely correlated with the proliferation indices of the tumours.

Optimization of Synthesis of Agarose-Based Lectin Affinity Sorbents

Different amounts of wheat germ agglutinin were immobilized to agarose gel, previously activated by different amounts of the coupling agent divinyl sulfone. The effectiveness of these affinity sorbents was characterized specific binding of ovomucoid with the gel. These studies revealed the formation of clear optima in binding capacity of the affinity gel, depending on conditions of its synthesis. The ratio between the concentration of the coupling agent and immobilized lectin were found to be crucial for optimization of binding properties of the affinity sorbent.

Afferent and efferent projections of the inferior area 6 in the macaque monkey

The rostral part of the agranular frontal cortex (area 6) can be subdivided on the basis of its cytoarchitecture, enzymatic properties, and connections into two large sectors: a superior region, lying medial to the spur of the arcuate sulcus, and an inferior region, lying lateral to it. In this study we traced the afferent and efferent connections of the inferior region of area 6 by injecting small amounts of wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP) and fluorescent tracers (fast blue and diamidino yellow) into restricted parts of inferior area 6 and in physiologically determined fields of area 4. There is an ordered topographic pattern of connections between inferior area 6 and area 4. The region near the spur of the arcuate sulcus (hand field) projects to the area 4 hand field while the lateral part of inferior area 6 (mouth field) is connected with the corresponding field in area 4. The organization of the connections between the two fields is, however, different. The hand fields in area 6 and 4 have direct reciprocal projections, whereas the mouth field in the postarcuate cortex relays information to area 4 via a zone intermediate between the arcuate and the central sulcus. This zone corresponds to the cytochrome oxidase area F4 (Matelli, Luppino, and Rizzolatti: Behav. Brain Res. 18: 125-137, '85). The inferior area 6 also has topographically organized connections with the supplementary motor area. The inferior area 6 receives and sends fibers to a series of discrete cortical areas located in the lower cortical moiety (Sanides: The Structure and Function of the Nervous Tissue, Vol. 5. New York: Academic Press, pp 329-453, '72). These areas that form a broad ring around the central sulcus are the ventral bank of the principal sulcus and the adjacent area 46, the precentral operculum (PrOC), area SII (Jones and Burton: J. Comp. Neurol. 168:197-248, '76), the parietal operculum, and the rostral part of the inferior parietal lobule including the lower bank of the intraparietal sulcus. Finally, the inferior area 6 has sparse but consistent connections with insular and cingulate cortices. The functional significance of this complex pattern of connections is discussed.

Interaction of sialoglycoproteins with wheat germ agglutinin-sepharose of varying ratio of lectin to Sepharose. Use for the purification of mucin glycoproteins from membrane extracts.

The influence of varying the amount of wheat germ agglutinin immobilized on Sepharose beads on the binding of glycoproteins to these beads was investigated. A series of wheat germ agglutinin-Sepharose gels containing between 0.10 and 10.0 mg of lectin/ml of gel was prepared, and the actual lectin content was established by acid hydrolysis of the gel followed by analysis of glycine, a major amino acid in wheat germ agglutinin. Affinity chromatography of labeled glycoproteins indicated that glycophorin bound to all the wheat germ agglutinin-Sepharose preparations. Fetuin, ovomucoid, and alpha 1-acid glycoprotein bound not at all or very poorly to gels with a low content of wheat germ agglutinin (less than 0.95 mg/ml). The specific binding of these glycoproteins increased with increasing lectin content on the gels, and on gels of high content (greater than 3 mg/ml) the binding was virtually quantitative. On chromatographing a mixture of glycophorin, alpha 1-acid glycoprotein, fetuin, and ovomucoid on wheat germ agglutinin-Sepharose, containing 0.08 mg of lectin/ml of gel, glycophorin was selectively retained on the gel. It was possible to purify glycophorin from an extract of human erythrocyte membranes in one step by chromatography on the above gel. By using the series of gels, it was demonstrated that Morris hepatoma 7777 membranes contained at least 4-fold more sialoglycoproteins which bound to low density wheat germ agglutinin-Sepharose compared to rat liver membranes. These hepatoma sialoglycoproteins were isolated, purified, and partially characterized as having a high proportion of O-linked sialyloligosaccharides. Our studies illustrate the use of low density wheat germ agglutinin-Sepharose gels both for the detection and for easy isolation of mucin-type glycoproteins from crude extracts of cells or membranes.

Characterization of a wheat germ agglutinin-like lectin from adult wheat plants

Radioimmuno-and enzyme-linked immunosorbent assays show that a substantial amount of wheat germ agglutinin(WGA)-like protein is present at the base of the shoot and in the roots of adult wheat (Triticum aestivum L.) plants. The protein can be purified by hapten-and antibody-mediated affinity procedures. It forms an arc of identity with the embryo lectin upon Ouchterlony double-diffusion and is an active lectin that agglutinates trypsinized erythrocytes in an N-acetylglucosamine-and chitin-inhibitable manner. Reduced and carboxyamidated protein comigrates with the 18-kdalton subunits of embryo lectin on sodium dodecyl sulfate-polyacrylamide gels. Invivo labeling of 9-d-old, hydroponically grown plants with (35)S-labeled sulfate demonstrates that at least some of the WGA-like protein is synthesized de novo. Immunocytochemistry with rabbit anti-WGA and colloidal-gold-conjugated second antibody shows that cross-reactive protein is present at the tips of new adventitious roots. In reactive cells, the lectin is localized near the inner surface of the vacuole membrane. Wheat plants contain up to 100 ng of WGA-like protein after the first week of growth, but the level fluctuates thereafter. Since most of the lectin is present at the base of the shoot and much less is found in older roots, these fluctuations may be the consequence of changes in the initiation of new advantitious roots.

Changes in the binding of concanavalin A and wheat germ agglutinin to human lymphocytes during [formula omitted] transformation

Concanavalin A binds to human circulating lymphocytes in a complex manner suggesting the presence of multiple binding sites. Saturation of one or more of these binding sites is observed at concentrations of concanavalin A which induce blast transformation in lymphocytes. In contrast, only one saturable binding site is observed for wheat germ agglutinin. During in vitro transformation, the amount of concanavalin A which can be bound by lymphocytes increases, whereas the amount of wheat germ agglutinin which can be bound remains unchanged. Since the size increases during transformation, there must be a fall in the density of surface receptors for wheat germ agglutinin whereas the density of concanavalin A receptors remains unchanged.