Electron microscope assessment of fertilization of rabbit ova treated with Concanavalin A and Wheat Germ Agglutinin

1976 ◽  
Vol 198 (3) ◽  
pp. 437-442 ◽  
Author(s):  
M. Gordon ◽  
P. V. Dandekar
Keyword(s):  
Electron Microscope ◽  
Concanavalin A ◽  
Wheat Germ Agglutinin ◽  
Wheat Germ

scholarly journals Receptor-mediated gonadotropin action in the ovary. Inhibitory actions of concanavalin A and wheat-germ agglutinin on gonadotropin-stimulated cyclic AMP and progesterone responses in ovarian cells

1981 ◽  
Vol 200 (1) ◽  
pp. 153-159 ◽  
Author(s):  
S Azhar ◽  
K M Menon
Keyword(s):  
Cyclic Amp ◽  
Concanavalin A ◽  
Wheat Germ Agglutinin ◽  
Wheat Germ ◽  
Carbohydrate Chain ◽  
Inhibitory Effect ◽  
Dolichos Biflorus ◽  
Acetylneuraminic Acid ◽  
Ovarian Cells ◽  
Proline Incorporation

Pretreatment of ovarian cells with concanavalin A and wheat-germ agglutinin blocked the gonadotropin-induced cyclic AMP and progesterone responses and this effect was time- and concentration-dependent. Basal production of either cyclic AMP or progesterone, however, was not affected by treatment of cells with lectin. The effect of concanavalin A on gonadotropin-mediated cyclic AMP and progesterone responses was blocked by alpha-methyl D-mannoside and alpha-methyl d-glucoside. Similarly the inhibitory effect of wheat-germ agglutinin was reversed by N-acetyl-D-glucosamine. Pretreatment of ovarian cells with concanavalin A or wheat-germ agglutinin had no effect on protein synthesis in the ovary as monitored by [3H]proline incorporation studies. Concanavalin A and wheat-germ agglutinin did not affect steroid production in response to dibutyryl cyclic AMP and 8-bromo cyclic AMP, indicating that the inhibitory action of lectin was occurring at a step before cyclic AMP formation. Lectins specific for L-fucose, D-galactose and N-acetyl-D-galactosamine, gorse seed agglutinin, peanut agglutinin and Dolichos biflorus agglutinin respectively, did not interfere with gonadotropin-induced cyclic AMP and progesterone responses. The present studies suggest that gonadotropin receptors may be glycoprotein in nature or closely associated with glycoprotein structures with the carbohydrate chain containing N-acetyl-D-glucosamine, mannose and possibly N-acetylneuraminic acid.

An ultrastructural study of the effects of wheat germ agglutinin (WGA) on cell cortex organization during the first cleavage of Xenopus laevis eggs. II. Cortical wound healing

1979 ◽  
Vol 37 (1) ◽  
pp. 59-67
Author(s):  
M. Geuskens ◽  
R. Tencer
Keyword(s):  
Wound Healing ◽  
Plasma Membrane ◽  
Electron Microscope ◽  
Xenopus Laevis ◽  
Ultrastructural Study ◽  
Wheat Germ Agglutinin ◽  
Wheat Germ ◽  
Cell Cortex ◽  
Animal Pole ◽  
Annular Zone

Uncleaved fertilized eggs of Xenopus laevis treated with wheat germ agglutinin (WGA) have been pricked at the animal pole both inside and outside the regressed furrow region. The wounded cortex of both regions has been studied with the electron microscope and compared with the same region of wounded, untreated eggs. In all 3 cases, filaments are organized in an annular zone in the damaged cortex. When the surface is pricked outside the regressed furrow of WGA-treated embryos, bundles of microfilaments radiate from the ring and extend in deep folds which form a ‘star’ around the wound at the surface of the embryo. However, when the surface is pricked in the new membrane of the regressed furrow, filaments are intermingled with internalized portions of the plasma membrane. It is suggested that, when the surface is pricked outside the furrow region, more filaments are mobilized to counteract the tangential retraction of the membrane which has acquired more rigidity after WGA binding.

Inhibition of H+ secretion by lectins in turtle bladder: role of a cell type on acidification

1985 ◽  
Vol 248 (5) ◽  
pp. R584-R594
Author(s):  
D. M. Potter ◽  
J. A. Arruda
Keyword(s):  
Concanavalin A ◽  
Wheat Germ Agglutinin ◽  
Wheat Germ ◽  
Granular Cell ◽  
Cell Fraction ◽  
Dependent Manner ◽  
O2 Consumption ◽  
Cell Type ◽  
Double Labeling ◽  
Morphological Studies

Because certain lectins have been shown to bind to the intercalated cell of the cortical collecting tubule, we investigated the effect of concanavalin A and wheat germ agglutinin on urinary acidification in isolated turtle bladders. After addition to the mucosal but not serosal fluid, concanavalin A and wheat germ agglutinin decreased H+ secretion in a dose-dependent manner, and these effects were specifically inhibited by the competitive antagonists of concanavalin A (alpha-methyl-D-mannoside) and of wheat germ agglutinin (N-acetylglucosamine). Concanavalin A decreased H+ secretion by decreasing both the proton motive force and the active conductance of protons. Although electroneutral HCO3 secretion was not inhibited by either lectin, Na transport was decreased by 18 and 25%, respectively, after concanavalin A and wheat germ agglutinin. Concanavalin A failed to inhibit O2 consumption by the granular cell fraction but significantly inhibited O2 consumption by the carbonic anhydrase rich cell fraction. Morphological studies utilizing peroxidase or fluorescein-labeled concanavalin A showed that concanavalin A stained one cell type and that this staining was specific since it could be blocked by the competitive antagonist alpha-methyl-D-mannoside. Studies utilizing double labeling with fluorescein concanavalin A and acridine orange suggested that both probes stain the same cell type. The data strongly suggest that concanavalin A interacts specifically with the cell responsible for H+ secretion.

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