Effects of concanavalin A on developing ganglion cells in the retina of chick embryos

Development ◽  
1981 ◽  
Vol 65 (1) ◽  
pp. 27-39
Author(s):  
K. Meller
Keyword(s):  
Cell Death ◽  
Concanavalin A ◽  
Ganglion Cells ◽  
Positional Information ◽  
Chick Embryos ◽  
Con A ◽  
The Third ◽  
Receptor Sites ◽  
Retinal Neurogenesis ◽  
Natural Cell

The administration of concanavalin A (Con A) (50–200 µg/egg) to chick embryos between the third and the seventh day of incubation has the following effects on the retina: (1) Con A causes the degeneration of a large number of ganglion cells and consequently the layer that should be formed by these cells is not present or is constituted only by a small number of ganglion cells. (2) The lectin seems to be effective only when it is administered during the postmitotic phase of the ganglion cells. (3) The degenerated cells are phagocytosed by the Müller cells in a manner similar to that occurring during the natural cell death in normal retinal development. (4) The differentiation of other retinal elements (photoreceptors, bipolar, amacrine and Müller cells) is not affected by the lectin administration. (5) The administration of Con A in later stages of development, even at ten times higher dosages (2000 µg/egg), fails to affect retinal neurogenesis. It is suggested that Con A binding to receptor sites of the cell membrane affects the distribution or mobility of surface components producing an alteration in the mechanism by which the developing cells regulate positional information during retinal neurogenesis.

Adhesion of Phytophthora palmivora zoospores: detection and ultrastructural visualization of concanavalin A-receptor sites appearing during encystment

1975 ◽  
Vol 19 (1) ◽  
pp. 11-20
Author(s):  
V.O. Sing ◽  
S. Bartnicki-Garcia
Keyword(s):  
Electron Microscopy ◽  
Cell Surface ◽  
Concanavalin A ◽  
Solid Surfaces ◽  
Trypsin Digestion ◽  
Phytophthora Palmivora ◽  
Con A ◽  
Binding Material ◽  
Ultraviolet Microscopy ◽  
Receptor Sites

The binding of concanavalin A (Con A) to the cell surface of zoospores and cysts of Phytophthora palmivora was studied by radiometry (125I-Con A), ultraviolet microscopy (fluorescein-Con A) and electron microscopy peroxidase-diaminobenzidine technique). Zoospores were found to secrete during the early stages of encystment a Con A-binding material susceptible to trypsin digestion. This glycoprotein is contained in the so-called peripheral vesicles and is probably responsible for the adhesion of the encysting zoospores to solid surfaces.

scholarly journals Concanavalin-A Induces Granulosa Cell Death and Inhibits FSH-Mediated Follicular Growth and Ovarian Maturation in Female Rats

Endocrinology ◽  
2013 ◽  
Vol 154 (5) ◽  
pp. 1885-1896 ◽  
Author(s):  
Ethel V. Velasquez ◽  
Mariana Ríos ◽  
María Elena Ortiz ◽  
Carlos Lizama ◽  
Elizabeth Nuñez ◽  
...  
Keyword(s):  
Cell Death ◽  
Granulosa Cell ◽  
Granulosa Cells ◽  
Concanavalin A ◽  
Ex Vivo ◽  
Female Rats ◽  
Carbohydrate Binding ◽  
Con A ◽  
Follicular Maturation

Abstract Reproductive success stems from a finely regulated balance between follicular maturation and atresia, in which the role of carbohydrate structure is poorly understood. Here, we describe for the first time a fraction of purified recombinant human FSH that is capable of bringing about the cell death of granulosa cells and preventing follicular maturation in a rat model. Further analysis by mass spectrometry revealed the presence of the lectin Concanavalin-A (Con-A) within this fraction of recombinant FSH. Using both the fractionated FSH and Con-A, the observed cell death was predominantly located to the granulosa cells. Ex vivo culture of rat follicles demonstrated that follicle degeneration occurred and resulted in the release of a denuded and deteriorated oocyte. Moreover, in vivo experiments confirmed an increase in atresia and a corresponding reduction confined to follicle in early antral stage. As a mechanism of action, Con-A reduces ovarian proliferation, Von Willebrand staining, and angiogenesis. Based on the observation that Con-A may induce granulosa cell death followed by follicle death, our results further demonstrate that follicular carbohydrate moiety is changing under the influence of FSH, which may allow a carbohydrate-binding lectin to increase granulosa cell death. The physiological consequences of circulating lectin-like molecules remain to be determined. However, our results suggest a potential exploitation of carbohydrate binding in fertility and ovarian cancer treatment. This work may shed light on a key role of carbohydrates in the still obscure physiological process of follicular selection and atresia.

The distribution of Concanavalin A receptor sites on the membrane of chromaffin granules

1975 ◽  
Vol 19 (1) ◽  
pp. 33-54
Author(s):  
P.A. Eagles ◽  
L.N. Johnson ◽  
C. Van Horn
Keyword(s):  
Concanavalin A ◽  
Plasma Membranes ◽  
Asymmetric Distribution ◽  
Chromaffin Granules ◽  
Intracellular Membrane ◽  
Chromaffin Granule ◽  
Binding Studies ◽  
Cell Cytoplasm ◽  
Con A ◽  
Receptor Sites

The distribution of concanavalin A (con A) receptor sites on the membranes of chromaffin granules has been investigated by binding studies using 125I-labelled con A and by electron-microscope studies using ferritin-labelled con A. In both experiments con A was observed to bind to chromaffin granule membranes but not to intact granules. The ferritin-con A particles bind to only one of the two possible surfaces of the chromaffin granule membranes. These results are in agreement with previous observations concerning the asymmetric distribution of saccharide residues on the surfaces of a number of different plasma membranes. They suggest that for the intracellular membrane of the chromaffin granule the saccharide sites, like those in plasma membranes, are not exposed to the cell cytoplasm. Further work is necessary to establish whether these sites are on the inner surface of the membrane or whether they are unmasked during the conversion of granules to membrane ghosts.

Electron microscopic localization of concanavalin A receptor sites in pollen surface material after fixation with glutaraldehyde-cetylpyridinium chloride.

1984 ◽  
Vol 32 (8) ◽  
pp. 869-871 ◽  
Author(s):  
M Grote ◽  
H G Fromme
Keyword(s):  
Concanavalin A ◽  
Cetylpyridinium Chloride ◽  
Pollen Grains ◽  
Dense Material ◽  
Con A ◽  
Electron Microscopic ◽  
Electron Dense Material ◽  
Receptor Sites ◽  
Pollen Surface ◽  
Ultrathin Sections

Pollen from birch trees (Betula pendula) was fixed in glutaraldehyde containing 0.5% cetylpyridinium chloride (CPC), incubated with concanavalin A (Con A)-ferritin, postfixed in osmium, dehydrated, and embedded in Epon. On ultrathin sections, ferritin particles were observed closely associated with the electron-dense material precipitated by CPC on the surface of the pollen grains. Controls for CPC, which were fixed in glutaraldehyde alone, showed no electron-dense material on the surface. In controls for Con A, which were incubated in Con A-ferritin in the presence of the inhibitory sugar (alpha-methyl-D-mannopyranoside), no ferritin particles were observed. The above-described procedure thus allows the localization of sugar residues in highly soluble pollen wall glycoproteins.

scholarly journals Ultrastructural localization of concanavalin A and wheat germ agglutinin binding sites in adult and embryonic mouse myocardium.

1982 ◽  
Vol 30 (3) ◽  
pp. 193-200 ◽  
Author(s):  
D Gros ◽  
B Bruce ◽  
C E Challice ◽  
J Schrevel
Keyword(s):  
Concanavalin A ◽  
Wheat Germ Agglutinin ◽  
Wheat Germ ◽  
Ultrastructural Localization ◽  
Embryonic Cells ◽  
Con A ◽  
Embryonic Mouse ◽  
Transverse Tubular System ◽  
Receptor Sites ◽  
Ultrathin Sections

The lectins, concanavalin A (Con A) and wheat germ agglutinin (WGA), have been used to localize with precision glycosyl residues in adult and embryonic mouse myocardium. They were detected by means of an affinity method using peroxidase and chitobiosylperoxidase, respectively, which then were revealed with 3,3'-diaminobenzidine and H2O2. Exhaustive controls have shown that the binding of Con A and WGA is reversible when experiments are performed with adult specimens (tissue blocks or ultrathin sections of glycol methacrylate-embedded material) or with isolated embryonic cells. Experiments carried out with tissue blocks from embryonic hearts have shown peroxidase binding. This finding is discussed on the basis of the presence of the endogenous lectin-like components in embryonic hearts. Results show that the surface of adult and embryonic myocardial cells specifically bind both Con A and WGA, thus indicating the presence of glycosyl residues similar to alpha-methyl-D-mannoside and N-acetyl-D-glucosamine. In adult heart the transverse tubular system was also labeled. The absence of Con A and WGA receptor sites in the gap junction regions was demonstrated by means of an electron microscope postembedding staining method.

scholarly journals THE EFFECT OF TOASTING, DRY UREA TREATMENT AND SPROUTING ON SOME THERMOSTABLE TOXIC FACTORS IN THE JACKBEAN SEED

2021 ◽  
Vol 25 (1) ◽  
pp. 36-39
Author(s):  
B. O. ESOUN ◽  
A. B. I. UDEDIBIE ◽  
C. R. CARLINI
Keyword(s):  
Concanavalin A ◽  
Crude Protein ◽  
Appreciable Effect ◽  
Con A ◽  
Feed Ingredient ◽  
Urea Treatment ◽  
The Third ◽  
Toxicological Studies ◽  
Ruminant Animals ◽  
Toxic Factors

Raw unprocessed jackbean seed contains 26 – 32% crude protein and also toxic elements most of which are thermostable, which limit its use as feed ingredient for livestock especially non-ruminant animals. Raw jackbean seeds were divided into three batches. One batch was ground and toasted, the second, batch was ground raw and mixed with 2% of its weight of dry area and allowed to stand for 11days. The third batch was sprouted for four days and later ground into meal. Toxicological studies on the batches of the jackbean meals were conducted for concanavalin A (Con A) and canatoxin in jackbean seed, while sprouting was effective in detoxifying concanavalin A (Con A) and canatoxin but not very effective in detoxifying the urease activity in jackbean seed. Toasting alone did not have appreciable effect on these toxic factors

The role of the cell surface in the migration of primordial germ cells in early chick embryos: effects of concanavalin A

Development ◽  
1978 ◽  
Vol 46 (1) ◽  
pp. 5-20
Author(s):  
H. Lee ◽  
N. Karasanyi ◽  
R. G. Nagele
Keyword(s):  
Cell Surface ◽  
Germ Cells ◽  
Concanavalin A ◽  
Primordial Germ Cells ◽  
Sublethal Dose ◽  
Chick Embryos ◽  
Con A ◽  
And Migration ◽  
Coat Material

Effects of concanavalin A (Con A) on the morphology and migration of primordial germ cells (PGCs) in stage-6 to -12 chick embryos were investigated. Con A, at a sublethal dose (10µg/ml), inhibited migration of PGCs from the germinal crescent area to other parts of the embryo. Affected PGCs were more rounded without the usual cytoplasmic extensions, but the integrity of other structures was unaffected. Nearly identical results were obtained with another lectin, wheat germ agglutinin (10µg/ml). Histochemistry using Con A-horseradish peroxidase revealed that PGCs in control embryos had a thin, rather uniform layer of extracellular coat material (ECM). Con A appeared to alter the distribution of ECM on PGCs, i.e. some parts of the cell surface were devoid of any detectable ECM, while others had small, scattered patches of ECM. Con A effects were alleviated by α-methyl-d-mannoside. Overall results of the present study indicated that the observed inhibition of PGC migration in early chick embryos is a consequence of Con A-induced alterations of cell surface properties.

A structural basis for four distinct elution profiles on concanavalin A – Sepharose affinity chromatography of glycopeptides

1979 ◽  
Vol 57 (1) ◽  
pp. 83-96 ◽  
Author(s):  
Saroja Narasimhan ◽  
James R. Wilson ◽  
Eva Martin ◽  
Harry Schachter
Keyword(s):  
Affinity Chromatography ◽  
Weak Interaction ◽  
Concanavalin A ◽  
Tight Binding ◽  
Structural Basis ◽  
Con A ◽  
Mannose Residue ◽  
Terminal Residue ◽  
The Third ◽  
Profile Type

Twelve 14C-acetylated glycopeptides have been subjected to affinity chromatography on concanavalin A (Con A) – Sepharose at pH 7.5. The elution profiles could be classified into four distinct patterns. The first pattern showed no retardation of glycopeptide on the column and was elicited with a glycopeptide having three peripheral oligosaccharide chains:[Formula: see text]Such glycopeptides have only a single mannose residue capable of interacting with Con A – Sepharose; an interacting mannose residue is either an α-linked nonreducing terminal residue or an α-linked 2-O-substituted residue. The second type of profile showed a retarded elution of glycopeptide with buffer lacking methyl α-D-glucopyranoside (indicative of weak interaction with the column) and was given by glycopeptides with the structures:[Formula: see text]where R1 is either H or a sialyl residue. The third profile type showed tight binding of glycopeptide to Con A – Sepharose and elution as a sharp peak with 0.1 M methyl α-D-glucopyranoside; glycopeptides giving this pattern had the structures:[Formula: see text]where R2 is either H, GlcNAc, Gal-β1,4-GlcNAc, or sialyl-Gal-β1,4-GlcNAc. These glycopeptides all have two interacting mannose residues, the minimum required for binding to the column; one of these mannose residues must, however, be a terminal residue to obtain tight binding and sharp elution. The fourth profile type showed tight binding of glycopeptide to the column but elution with 0.1 M methyl α-D-glucopyranoside resulted in a broad peak indicating very tight binding; glycopeptides showing this behaviour had the structures:[Formula: see text]where R3 is either GlcNAc, Gal-β1,4-GlcNAc, or siaryl-Gal-β1,4-GlcNAc. Therefore it can be concluded that although a minimum of two interacting mannose residues is required for binding to Con A – Sepharose, the residues linked to these mannoses can either strengthen or weaken binding to the column.

Fractionation of large glycopeptides of human teratocarcinoma-derived cells by concanavalin A – Sepharose chromatography

1980 ◽  
Vol 58 (4) ◽  
pp. 281-286 ◽  
Author(s):  
Maija-Liisa Rasilo
Keyword(s):  
Concanavalin A ◽  
Gel Filtration ◽  
Neuraminic Acid ◽  
Void Volume ◽  
Con A ◽  
The Third ◽  
Large Size

Human teratocarcinoma derived cells, line PA 1, were labeled with radioactive monosaccharides and subsequently digested with pronase. Large sized glycopeptides (fraction A) were isolated by gel filtration on Bio-Gel P-10. Their chromatography on concanavalin A – Sepharose gave three subfractions, two of which were eluted with a sugar-free buffer and the third with 10 mM α-methyl mannoside. The first subfraction (fraction A – Con A Ia) incorporated label from [3H]galactose and [3H]glucosamine and contained the largest components of fraction A. The second and the third subfractions (fractions A – Con A Ib and A – Con A II) were glycopeptides which incorporated label from tritiated fucose, mannose, galactose, and glucosamine. Even these molecules were of large size eluting partially at the void volume from Bio-Gel P-60. The glycopeptides of fraction A – Con A Ib contained mannose, fucose, galactose, N-acetylglucosamine, and N-acetylgalactosamine. Fucose and galactose residues occupied ultimate or penultimate positions at the nonreducing termini of the oligosaccharides. N-Acetyl-neuraminic acid, too, was present in the glycopeptides of fraction A.

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