scholarly journals Membrane structure and surface coat of Entamoeba histolytica. Topochemistry and dynamics of the cell surface: cap formation and microexudate.

1975 ◽  
Vol 64 (3) ◽  
pp. 538-550 ◽  
Author(s):  
P P Silva ◽  
A Martínez-Palomo ◽  
A Gonzalez-Robles
Keyword(s):  
Plasma Membrane ◽  
Cell Surface ◽  
Binding Sites ◽  
Membrane Structure ◽  
Ruthenium Red ◽  
Iron Binding ◽  
Con A ◽  
Colloidal Iron ◽  
Acidic Sites ◽  
Membrane Components

Treatment of living entamoeba histolytica cells with low concentrations of concanavalin A (con A) and peroxidase results in redistribution of the plasma membrane con A receptors to one pole of the cell where a morphologically distinct region--the uroid--is formed. Capping of con A receptors is not accompanied by parallel accumulation of ruthenium red-stainable components. In capped cells, the pattern of distribution of acidic sites ionized at pH 1.8 (labeled by colloidal iron) at the outer surface and of membrane particles (integral membrane components revealed by freeze-fracture) is not altered over the uroid region. Cytochemistry of substrate-attached microexudate located in regions adjacent to E. histolytica cells demonstrates the presence of con A binding sites and ruthenium red- and alcian blue-stainable components and the absent of colloidal iron binding sites. In a previous report we demonstrated that glycerol-induced aggregation of the plasma membrane particles is accompanied by a discontinuous distribution of colloidal iron binding sites, while con A receptors and acidic sites ionized at pH 4.0 remain uniformly distributed over the cell surface. Taken together, our experiments show that, in E. histolytica cells, peripheral membrane components may move independently of integral components and, also, that certain surface determinants may redistribute independently of others. These results point to the complexity of the membrane structure-cell surface relationship in E. histolytica plasma membranes relative to the membrane of the erythrocyte ghost where integral components (the membrane-intercalated particles) contain all antigens, receptors, and anionic sites labeled so far. We conclude that fluidity of integral membrane components (integral membrane fluidity) cannot be inferred from the demonstration of the mobility of surface components nor, conversely, can the fluidity of peripheral membrane components (peripheral membrane fluidity) be assumed from demonstration of the mobility of integral membrane components.

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.

scholarly journals Topographical differences in the distribution of surface coat components and intramembrane particles. A cytochemical and freeze-fracture study in culture forms of Trypanosoma cruzi.

1976 ◽  
Vol 69 (2) ◽  
pp. 507-513 ◽  
Author(s):  
A Martínez-Palomo ◽  
W DeSouza ◽  
A Gonzalez-Robles
Keyword(s):  
Plasma Membrane ◽  
Binding Sites ◽  
Freeze Fracture ◽  
Ruthenium Red ◽  
Regional Differentiation ◽  
Surface Coat ◽  
Colloidal Iron ◽  
Regional Specialization ◽  
Poor Region ◽  
Fracture Study

A regional specialization of the cell surface of T. cruzi culture forms was found at the cytostome as a localized thick surface coat rich in carbohydrate-containing components. The prominent surface coat was located over a region of the plasma membrane where intramembranous particles were exceedingly low in number. In turn, the particle-poor region was related to specialized submembrane fibrils not present under other regions of the plasma membrane. The cystostome region provides a striking example of a stable regional differentiation of the plasma membrane, involving the outer surface, the membrane interior, and the underlying cytoplasm. In addition, independence of Con A receptors, colloidal iron binding sites, and ruthenium red-stainable surface components from membrane particles was demonstrated at the flagellar membrane.

Opisthorchis viverrini: ultrastructure and cytochemistry of the glycocalyx of the tegument

2000 ◽  
Vol 74 (1) ◽  
pp. 23-29 ◽  
Author(s):  
W. Apinhasmit ◽  
P. Sobhon ◽  
C. Tarasub ◽  
W. Mothong ◽  
P. Saitongdee ◽  
...  
Keyword(s):  
Sialic Acid ◽  
Binding Sites ◽  
Ricinus Communis ◽  
Ruthenium Red ◽  
Opisthorchis Viverrini ◽  
Binding Studies ◽  
Con A ◽  
Colloidal Iron ◽  
Dolichos Biflorus ◽  
Ulex Europaeus

AbstractThe ultrastructure and cytochemistry of the glycocalyx of the tegument of Opisthorchis viverrini during maturation from newly excysted juvenile to adult stages were investigated using colloidal iron, ruthenium red and lectin stainings. The results showed that the glycocalyx was intensely stained by the first two dyes, thus indicating the presence of relatively high amounts of negative charges. However, the thickness and intensity of the staining decreased during the fluke's maturation. Binding studies using lectin probes on the surface of adult parasites showed that binding sites for Canavaliaensiformis (Con A), Triticum vulgaris (WGA) and Ricinus communis I(RCA I) were present in relative large amounts on the glycocalyx of the adult tegument, whereas those for Dolichos biflorus (DBA) were relatively fewer in number, and those for Ulex europaeus I (UEA I) were absent. The binding patterns of Con A, WGA, RCA I and DBA were generally similar, and the reaction product was uniformly distributed over the dorsal and ventral surfaces of the parasite's body. These bindings, therefore, indicate the presence of D-mannose/D-glucose, N-acetyl-D-glucosamine/sialic acid, D-galactose and N-acetyl-D-galactosamine residues on the glycocalyx of the adult tegument.

Target cell surface glycoconjugates and neural induction in an amphibian

Development ◽  
1985 ◽  
Vol 86 (1) ◽  
pp. 39-51
Author(s):  
Lydie Gualandris ◽  
Pierre Rouge ◽  
Anne-Marie Duprat
Keyword(s):  
Cell Surface ◽  
Binding Sites ◽  
Neural Induction ◽  
Specific Receptor ◽  
Con A ◽  
Neural Signal ◽  
Electrophysiological Properties ◽  
Ionic Fluxes ◽  
Target Membrane ◽  
Cell Surface Glycoconjugates

The possible involvement of target membrane specific receptor(s) in the transmission of the neural signal leading to activation of the intracellular machinery involved in the process of neural determination, has been examined using lectin probes (Con A, succinylated-ConA, LcA, PsA and SBA). Not only Con A binding sites but many different glycoconjugated molecules (α-Dgalactose, N-acetyl-D-galactosamine, α-D-fucose, N-acetyl-D-glucosamine, etc.) would have to be involved, if neural receptor(s) are invoked to explain initiation of neural induction. We show here that the close involvement of such receptor molecules in neural induction is so far hypothetical and remains to be demonstrated. Moreover we are inclined to the view of Barth and others who suggested that ionic fluxes and physicochemical and electrophysiological properties of the target membrane could play a crucial role in neural induction.

Participation of concanavalin A binding sites in the interaction between Trypanosoma cruzi and macrophages

1983 ◽  
Vol 62 (1) ◽  
pp. 287-299
Author(s):  
M.N. Meirelles ◽  
A. Martinez-Palomo ◽  
T. Souto-Padron ◽  
W. De Souza
Keyword(s):  
Plasma Membrane ◽  
Cell Surface ◽  
Trypanosoma Cruzi ◽  
Uniform Distribution ◽  
Concanavalin A ◽  
Binding Sites ◽  
Peritoneal Macrophages ◽  
Untreated Mouse ◽  
Mouse Peritoneal Macrophages

Untreated mouse peritoneal macrophages as well as macrophages treated with concanavalin A (ConA) were incubated in the presence of untreated or ConA-treated epimastigotes and trypomastigotes of Trypanosoma cruzi. Treatment of epimastigotes or trypomastigotes with ConA increased or decreased their uptake by macrophages, respectively. Treatment of their macrophages with ConA reduced by 70% and increased by five times the ingestion of epimastigotes and trypomastigotes, respectively. These results are discussed in relation to previous studies on the mobility of ConA receptors in the membrane of the parasite. Using fluorescein- or ferritin-labelled ConA we observed that ConA binding sites located on the plasma membrane of macrophages are internalized during endocytosis of T. cruzi, and observed in association with the membrane of the endocytic vacuole. Vacuoles without parasites showed a uniform distribution of ConA binding sites, while these sites were distributed in patches in vacuoles containing parasites. These results, in association with others previously reported, suggest the involvement of glycoproteins and/or glycolipids localized on the cell surface of T. cruzi and macrophages during the T. cruzi-macrophage interaction.

Trypanosoma cruzi: cell surface dynamics in trypomastigotes of different strains

Parasitology ◽  
2019 ◽  
Vol 147 (3) ◽  
pp. 310-321
Author(s):  
Roberta Ferreira Cura das Neves ◽  
Camila Marques Adade ◽  
Anne Cristine Silva Fernandes ◽  
Angela Hampshire Lopes ◽  
Thaïs Souto-Padrón
Keyword(s):  
Cell Surface ◽  
Trypanosoma Cruzi ◽  
Binding Sites ◽  
Host Cells ◽  
Cationized Ferritin ◽  
Surface Dynamics ◽  
Con A ◽  
Low Intensity ◽  
Intense Labelling ◽  
Different Strains

AbstractCapping and shedding of ectodomains in Trypanosoma cruzi may be triggered by different ligands. Here, we analysed the mobility and shedding of cell surface components of living trypomastigotes of the Y strain and the CL Brener clone in the presence of poly-L-lysine, cationized ferritin (CF) and Concanavalin A (Con A). Poly-L-lysine and CF caused intense shedding in Y strain parasites. Shedding was less intense in CL Brener trypomastigotes, and approximately 10% of these parasites did not show any decrease in poly L-lysine or CF labelling. Binding of Con A induced low-intensity shedding in Y strain and redistribution of Con A-binding sites in CL Brener parasites. Trypomastigotes of the Y strain showed intense labelling with anti-〈-galactosyl antibodies, resulting in the lysis of approximately 30% of their population, in contrast with what was observed in CL Brener parasites. Incubation with Con A and CF protected trypomastigotes of the Y strain from lysis by anti-αGal. The last treatment did not interfere with the survival of the CL Brener parasites. This study corroborates with the idea that a ligand can differentially modulate the cell surface of T. cruzi, depending on the strain used, resulting in variable immune system responses and recognition by host cells.

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 Surface redistribution and release of antibody-induced caps in entamoebae.

1980 ◽  
Vol 151 (1) ◽  
pp. 184-193 ◽  
Author(s):  
J Calderón ◽  
M de Lourdes Muñoz ◽  
H M Acosta
Keyword(s):  
Plasma Membrane ◽  
Cell Surface ◽  
Surface Segregation ◽  
Surface Membrane ◽  
Single Layer ◽  
Surface Antigens ◽  
Spontaneous Release ◽  
Plasma Membrane Regeneration ◽  
Membrane Components ◽  
Radiolabeled Antibodies

Polyspecific antibodies bound to Entamoeba induced surface redistribution of membrane components toward the uroid region. Capping of surface antigens was obtained with a single layer of antibodies in E. histolytica and E. invadens. This surface segregation progressed to a large accumulation of folded plasma membrane that extruded as a defined vesicular cap. A spontaneous release of the cap at the end of the capping process took place. These released caps contained most of the antibodies that originally bound to the whole cell surface. Two-thirds of radiolabeled antibodies bound to the surface of E. histolytica were released into the medium in 2 h. Successive capping induced by repeated exposure of E. invadens to antibodies produced conglomerates of folded surface membrane, visualized as stacked caps, in proportion to the number of antibody exposures. These results indicate the remarkable ability of Entamoeba to rapidly regenerate substantial amounts of plasma membbrane. The properties of surface redistribution, liberation of caps, and plasma membrane regeneration, may contribute to the survival of the parasite in the host during infection.

scholarly journals alpha 2 Macroglobulin binding to the plasma membrane of cultured fibroblasts. Diffuse binding followed by clustering in coated regions.

1979 ◽  
Vol 82 (3) ◽  
pp. 614-625 ◽  
Author(s):  
M C Willingham ◽  
F R Maxfield ◽  
I H Pastan
Keyword(s):  
Plasma Membrane ◽  
Cell Surface ◽  
Coated Vesicles ◽  
The Other ◽  
Con A ◽  
Coated Pits ◽  
Cultured Fibroblasts ◽  
Receptor Complexes ◽  
Transmission Electron ◽  
Epidermal Growth

Using transmission electron microscopy, we have studied the interaction of alpha 2 macroglobulin (alpha 2 M) with the surface of cultured fibroblasts. When cells were incubated for 2 h at 4 degrees C with ferritin-conjugated alpha 2 M, approximately 90% of the alpha 2 M was diffusely distributed on the cell surface, and the other 10% was concentrated in "coated" pits. A pattern of diffuse labeling with some clustering in "coated" pits was also obtained when cells were incubated for 5 min at 4 degrees C with alpha 2 M, fixed with glutaraldehyde, and the alpha 2 M was localized with affinity-purified, peroxidase-labeled antibody to alpha 2 M. Experiments in which cells were fixed with 0.2% paraformaldehyde before incubation with alpha 2 M showed that the native distribution of alpha 2 M receptors was entirely diffuse without significant clustering in "coated" pits. This indicates that some redistribution of the alpha 2 M-receptor complexes into clusters occurred even at 4 degrees C. In experiments with concanavalin A(Con A), we found that some of the Con A clustered in coated regions of the membrane and was internalized in coated vesicles, but much of the Con A was directly internalized in uncoated vesicles or pinosomes. We conclude that unoccupied alpha 2 M receptors are diffusely distributed on the cell surface. When alpha 2 M-receptor complexes are formed, they rapidly cluster in coated regions or pits in the plasma membrane and subsequently are internalized in coated vesicles. Because insulin and epidermal growth factor are internalized in the same structures as alpha 2 M (Maxfield, F.R., J. Schlessinger, Y. Schechter, I. Pastan, and M.C. Willingham. 1978. Cell, 14: 805--810.), we suggest that all peptide hormones, as well as other proteins that enter the cell by receptor-mediated endocytosis, follow this same pathway.

The formation and function of the extraacrosomal layer and modification of the plasma membrane in spermiogenesis of Acrida lata motschulsky (Orthoptera)

1978 ◽  
Vol 36 (2) ◽  
pp. 570-571
Author(s):  
Gonpachiro Yasuzumi ◽  
Toshikatsu Asai
Keyword(s):  
Plasma Membrane ◽  
Fine Structure ◽  
Cell Surface ◽  
Membrane Structure ◽  
Early Stage ◽  
Cell Types ◽  
Unit Membrane ◽  
Sharp Point ◽  
Specific Proteins ◽  
And Function

Receptor-specific proteins are now being widely and usefully applied to the study of cell-surface topography. We have been actively interested in this field from the standpoint of spermiogenesis of the grasshopper. The surface of developing spermatids is in contact with other cells or with their environment, and in addition to carrying on metabolic processes necessary for maturation they must also exhibit the specificity that distinguishes cells from the same cell types from different individuales. The cell bodies of the grasshopper, Acrida lata Motschulsky, spermatids are spherical in the early stage of metamorphosis, but later they become conical and more and more elongate until they are long slender rods, rounded at the base and tapering at the tip to a sharp point. Concurrently with these changes in the spermatid cell bodies, the remarkable trans formation occurs in the fine structure of the cell-surface. In the early stage of maturation of spermatids, the cell-surface is smooth and consists of the unit membrane structure.

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