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 and wheat germ agglutinin receptors on dictyostelium: Their visualization by scanning electron microscopy with microspheres

1976 ◽  
Vol 71 (1) ◽  
pp. 314-322 ◽  
Author(s):  
R Molday ◽  
R Jaffe ◽  
D McMahon
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cell Surface ◽  
Wheat Germ ◽  
Cellular Interactions ◽  
Con A ◽  
Stages Of Development ◽  
Lectin Receptors ◽  
Plant Lectins ◽  
Scanning Electron

The cellular slime mold, Dictyostelium discoideum, is a convenient model for studying cellular interactions during development. Evidence that specific cell surface components are involved in cellular interactions during its development has been obtained by Gerisch and co-workers (1, 2) using immunological techniques. Smart and Hynes (3) have shown that a cell surface protein can be iodinated on cells in aggregation phase, but not in vegetative phase, by the lactoperoxidase procedure. Recently, McMahon et al. (4), and Hoffman and McMahon have demonstrated, by SDS gel electrophoresis, considerable differences in cell surface proteins and glycoproteins of plasma membranes isolated from cells at different stages of development. Plant lectins have also been used to monitor changes in cell surface properties of D. discoideum cells during development. Weeks and co-workers (5, 6) have detected differences in the binding and agglutination of cells by concanavalin A (Con A). Gillette and Filosa (7) have shown that Con A inhibits cell aggregation and prematurely induces cyclic AMP phosphodiesterase. Capping of Con A receptors has also been reported (8). Reitherman et al. (9) have recently reported that agglutination of cells by several plant lectins and the slime mold agglutination, discoidin, changes during development. Such studies indicate that differences in surface properties exist for cells at various stages of development. However, owing to the uncertainties in the factors which contribute to lectin-induced cell agglutination (10), the molecular basis for these observations remain to be determined. In this study, we have used microspheres (11-14) coupled to either Con A or wheat germ agglutinin (WGA) as visual markers to study by scanning electron microscopy the topographical distribution of lectin receptors on D. discoideum cells fixed at different stages of development. We also describe the effect of labeling on the distribution of lectin receptors and on the morphology of the cell surface.

scholarly journals Distribution of concanavalin A binding sites on the surface of dissociated rat submandibular gland acinar cells.

1975 ◽  
Vol 23 (8) ◽  
pp. 607-617 ◽  
Author(s):  
T Amakawa ◽  
T Barka
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Surface ◽  
Concanavalin A ◽  
Binding Sites ◽  
Lectin Binding ◽  
Single Cells ◽  
Apical Cell ◽  
Acinar Cells ◽  
Con A ◽  
Dissociated Cells

The submandibular glands of 4-week-old rats were dissociated by a procedure involving digestions with collagenase and hyaluronidase, chelation of divalent cations and mechanical force. A suspension of single cells was obtained in low yield by centrifugation in a Ficoll-containing medium. Immediately after dissociation and after a culture period of 16-18 hr the dissociated cells were tested for agglutinability by concanavalin A (Con A). Using ferritin (tfer)-conjugated Con A the lectin binding by the isolated acinar cells was also studied. The dissociated cells were agglutinated by low concentrations of Con A and bound Fer-Con A molecules on their entire surface without any indication of polarization of the cell membrane. There was a considerable cell to cell variation in the amount of Fer-Con A binding which was, in general, sparse and patchy. The contact surfaces between agglutinated cells revealed a dense binding of Fer-Con A molecules irrespective of the types of cells participating in the agglutination reaction. Cells cultured for 16-18 hr were no longer agglutinated by Con A. As compared to the freshly dissociated cells the cultured acinar cells revealed a more uniform and denser binding of Fer-Con A molecules. Furthermore, there were more lectin molecules bound to the cell surface corresponding to the basal part of the cell, where the nucleus and most of the rough surface endoplasmic reticulum were located, than to the apical cell surface. It is suggested that the higher density of lectin-binding sites on the cell surface in the vicinity of the cisternae of the rough endoplasmic reticulum indicates insertion sites of newly synthesized membrane glycoproteins.

scholarly journals Immune complex receptors on cell surface. I. Ultrastructural demonstration of macrophages.

1976 ◽  
Vol 24 (8) ◽  
pp. 948-955 ◽  
Author(s):  
P E McKeever ◽  
A J Garvin ◽  
S S Spicer
Keyword(s):  
Electron Microscopy ◽  
Horseradish Peroxidase ◽  
Cell Surface ◽  
Immune Complex ◽  
Immune Complexes ◽  
External Surface ◽  
Binding Capacity ◽  
Ultrastructural Localization ◽  
Soluble Complex ◽  
Receptor Sites

A method is described for ultrastructural localization of immune complex receptors on the surface of viable peritoneal exudate cells. The technique entails incubation with a soluble complex of horseradish peroxidase (HRP) and specific antibody to HRP at 4 degrees C followed by exposure to diaminobenzidine and processing for electron microscopy. The bound immune complexes were evident as focal deposits of HRP reaction product, adhering closely to the external surface of macrophages with an uninterrupted periodicity varying between 30 and 120 nm. Following incubation with an insoluble immune complex containing a higher proportion of antibody, receptor sites stained frequently, but large aggregates adhered to the cells. Rinsing cells after staining with soluble complexes partially displaced the bound immune complexes. Fixation prior to exposure to immune complexes largely eliminated the binding capacity of the immune complex receptors.

scholarly journals Reversibility of cell surface label rearrangement.

1976 ◽  
Vol 68 (3) ◽  
pp. 629-641 ◽  
Author(s):  
S S Brown ◽  
J P Revel
Keyword(s):  
Electron Microscopy ◽  
Cell Surface ◽  
Binding Sites ◽  
Random Distribution ◽  
Cytochalasin B ◽  
Con A ◽  
Original Distribution ◽  
Sensitive Structure ◽  
Membrane Components ◽  
Scanning Electron

Cell surface labeling can cause rearrangements of randomly distributed membrane components. Removal of the label bound to the cell surface allows the membrane components to return to their original random distribution, demonstrating that label is necessary to maintain as well as to induce rearrangements. With scanning electron microscopy, the rearrangement of concanavalin A (con A) and ricin binding sites on LA-9 cells has been followed by means of hemocyanin, a visual label. The removal of con A from its binding sites at the cell surface with alpha-methyl mannoside, and the return of these sites to their original distribution are also followed in this manner. There are labeling differences with con A and ricin. Under some conditions, however, the same rearrangements are seen with both lectins. The disappearance of labeled sites from areas of ruffling activity is a major feature of the rearrangements seen. Both this ruffling activity and the rearrangement of label are sensitive to cytochalasin B, and ruffling activity, perhaps along with other cytochalasin-sensitive structure, may play a role in the rearrangements of labeled sites.

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.

Cell Agglutination Mediated by Concanavalin A and the Dynamic State of the Cell Surface

1974 ◽  
Vol 14 (1) ◽  
pp. 197-202
Author(s):  
M. INOUE
Keyword(s):  
Cell Surface ◽  
Concanavalin A ◽  
Binding Sites ◽  
Dynamic Condition ◽  
Dynamic State ◽  
Con A ◽  
Cell Agglutination ◽  
Surface Receptors ◽  
Topographical Distribution ◽  
Ehrlich Ascites Tumour

The binding of 131I-labelled concanavalin A (131I-Con A) to the cell surface has been studied in Ehrlich ascites tumour cells (EATC) and beef erythrocytes under various conditions. The binding of concanavalin A (Con A) to the cell surface was very specific and the available binding sites were saturated within a few minutes. The amount of 131I-Con A bound to EATC was 4.14 x 107 molecules/cell at 37 °C and 2.12 x 107 molecules/cell at 0 °C. Under these conditions, cell agglutination was observed only at 37 °C and not at 0 °C. However, the binding sites measured at 0 °C were also effective for agglutination at 37 °C. Beef erythrocytes were agglutinated by Con A only after treatment of cells with papain. The number of binding sites for Con A on the cell surface was decreased by this treatment to about half the number present on untreated cells. Various reagents such as colchicine, monoiodoacetic acid, dinitrophenol, rotenone, sodium azide and carboxyl cyanide-m-fluorophenylhydrazone (FCCP) had no effect on Con A-mediated cell agglutination. In contrast, periodate treatment produced a remarkable decrease in the agglutinability of cells. From these data, it is concluded that the cell agglutination induced by Con A was due to the topographical distribution of the surface receptors for the lectin, and not the result of energy-dependent or microtubule-dependent reaction processes. The number and the state of Con A receptors on the cell surface were in a dynamic condition, their conformation, orientation, and/or topographical distribution changing under different conditions.

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 Distribution of receptor sites on large glycoprotein molecules by electron microscopy. Application to epiglycanin

1981 ◽  
Vol 193 (1) ◽  
pp. 203-207 ◽  
Author(s):  
H S Slayter ◽  
J F Codington
Keyword(s):  
Electron Microscopy ◽  
Concanavalin A ◽  
Active Sites ◽  
Ricinus Communis ◽  
Tumour Cells ◽  
Mammary Tumour ◽  
New Approach ◽  
Extended Conformation ◽  
Receptor Sites ◽  
Carbohydrate Chains

Electron microscopy was used to map the loci of immunochemically active sites on individual glycoprotein molecules. The positions of specific galactose residues and asparagine-linked carbohydrate chains containing specific mannose residues in epiglycanin, a glycoprotein of extended conformation from the surface of TA3 mouse mammary tumour cells, were observed in complexes with Ricinus communis toxin and concanavalin A respectively. The maximum number of Ricinus communis toxin molecules attached to a single epiglycanin molecule was 23, and the average number was 16. Only one concanavalin A molecule was observed attached to any epiglycanin molecule, and this at one end of the molecule, suggesting the presence of only one receptor for this lectin. By means of this new approach for mapping specific residues, evidence has been obtained that suggests microheterogeneity in epiglycanin with respect to the locations of carbohydrate chains containing receptors for Ricinus communis toxin.

scholarly journals Laser cytophotometric detection of variations in spatial distribution of concanavalin-A cell surface receptors following viral infection.

1977 ◽  
Vol 25 (7) ◽  
pp. 908-912 ◽  
Author(s):  
J F Leary ◽  
P Todd
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Cell Surface ◽  
Con A ◽  
Receptor Sites ◽  
Spatial Redistribution ◽  
A Cell ◽  
Infected Cells ◽  
Simplex Virus

Human cells in culture (H.Ep. 2) were infected with herpes simplex virus type 2 at a multiplicity of infection (m.o.i.) of 3 for 3, 18 and 36 hr. Spatial redistribution of concanavalin (Con-A) cell surface receptor sites was detected by an indirect double-antibody (peroxidase-conjugated goat anti-rabbit to rabbit anti-Con-A) immunoenzymatic staining reaction which rendered the Con-A sites visible to light microscopy and to flow laser cytophotometry. Significant spatial redistribution of cell surface Con-A receptor sites occurred within the first 3 hr after infection with herpes simplex virus type 2. The infected cells must be in the presence of Con-A for the redistribution to occur, and significant redistribution occurs only at 37 degrees C. Fixation of infected cells prior to application of Con-A prevented this spatial redistribution of Con-A receptor sites.

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.

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