Effects of colchicine and cytochalasin B on distribution of concanavalin A receptors in isolated and cultured guinea pig epidermal cells

1987 ◽  
Vol 279 (6) ◽  
pp. 392-397 ◽  
Author(s):  
M. Takigawa ◽  
K. Danno ◽  
F. Furukawa
Keyword(s):  
Guinea Pig ◽  
Concanavalin A ◽  
Cytochalasin B ◽  
Epidermal Cells ◽  
Concanavalin A Receptors

scholarly journals Nonuniform distribution of concanavalin-A receptors and surface antigens on uropod-forming thymocytes.

1978 ◽  
Vol 79 (1) ◽  
pp. 235-251 ◽  
Author(s):  
S de Petris
Keyword(s):  
Electron Microscopy ◽  
Normal Distribution ◽  
Concanavalin A ◽  
Cytochalasin B ◽  
Surface Antigens ◽  
Nonuniform Distribution ◽  
Inhomogeneous Distribution ◽  
Spherical Cells ◽  
Concanavalin A Receptors

Uropods can form spontaneously in a variable fraction of mouse thymocytes incubated for 30--60 min in vitro at temperatures between about 8 degrees and 37 degrees C. The majority of the cells with a typical uropod are medium and large thymocytes. The "normal" distribution of concanavalin-A receptors and antigens recognized by a rabbit anti-mouse thymocyte serum was studied on these cells by electron microscopy using ferritin-conjugated lectin or antibodies. The cells were fixed with glutaraldehyde or formaldehyde before labeling. The distribution was essentially uniform on spherical cells. On the contrary, on cells which had formed a uropod the labeled receptors and antigens appeared to be preferentially concentrated around the nucleus, and depleted over the uropod, and especially over the constriction at the base of the uropod. Uropod formation and inhomogeneous distribution were inhibited or reversed by cytochalasin B, but not by vinblastine or colchicine. When the same ligands were applied to unfixed cells, the labeled and cross-linked components capped normally towards the cytoplasmic pole of the cell. These observations are described in relation to the ability of receptors and antigens to interact with an intracellular mechanical structure, and to the mechanism of capping.

scholarly journals Kinetic evidence for a common mechanism of capping on lymphocytes

1982 ◽  
Vol 204 (1) ◽  
pp. 229-237 ◽  
Author(s):  
Anthony N. Corps ◽  
James C. Metcalfe ◽  
Tullio Pozzan
Keyword(s):  
Concanavalin A ◽  
Cytochalasin B ◽  
Specific Effect ◽  
Common Mechanism ◽  
Cross Linking ◽  
Detectable Effect ◽  
Membrane Flow ◽  
Surface Immunoglobulin ◽  
Fixed Times ◽  
Concanavalin A Receptors

1. Differences in the rates at which ligands cap various receptors on the same cells, and their sensitivity to various drugs, have been interpreted as evidence that there are distinct mechanisms for ‘fast’ and ‘slow’ cap formation. We have examined the factors which determine the rate of cap formation of three receptors on mouse splenic lymphocytes or thymocytes, and compared the effects of cytochalasin B or colchicine under conditions where the different receptors cap at similar rates. 2. When surface immunoglobulin, concanavalin A receptors, or θ antigen are induced to cap at their maximal rates by appropriate concentrations of one or more cross-linking ligands, the half-time for maximal capping of each receptor population is between 1.5 and 3.0min at 37°C. Slower rates of cap formation are obtained by using non-optimal concentrations of the cross-linking ligands. 3. When the three receptors were induced to cap at similar rates (either maximal or slower), 10μm-cytochalasin B caused a similar decrease in the rate of cap formation for each receptor, without affecting the eventual extent of capping. At comparable capping rates on control cells, colchicine (10μm) increased the rate of cap formation for surface immunoglobulin and concanavalin A receptors to a similar extent, without affecting the eventual extent of cap formation. In contrast, colchicine had no detectable effect on the capping of θ antigen. 4. From these results, we conclude that there are no intrinsic differences in the rates at which different receptors can be induced to cap that can be used to diagnose differences in their mechanisms of cap formation. The observation that ligand concentration and the drugs acting on the cytoskeleton generally affect the rate but not the extent of cap formation accounts for the wide variation in reported effects of the drugs on cap formation measured at fixed times. The receptor-specific effect of colchicine on surface immunoglobulin and concanavalin A receptors, but not θ antigen, is not readily compatible with models of cap formation which depend on lipid or membrane flow.

scholarly journals Concanavalin A receptors, immunoglobulins, and theta antigen of the lymphocyte surface. Interactions with concanavalin A and with Cytoplasmic structures.

1975 ◽  
Vol 65 (1) ◽  
pp. 123-146 ◽  
Author(s):  
S de Petris
Keyword(s):  
Electron Microscopy ◽  
Concanavalin A ◽  
Cytochalasin B ◽  
Active Role ◽  
Spleen Cells ◽  
Con A ◽  
Lymphocyte Surface ◽  
Antimitotic Drugs ◽  
Cytoplasmic Structures ◽  
Concanavalin A Receptors

The effect of concanavalin A (Con A) on the capping of mouse lymphocyte surface immunoglobulin (surface Ig), cross-linked by rabbit anti-mouse Ig antibody, and on the capping of mouse thymocyte theta antigen, cross-linked by anti-theta alloantibody and rabbit anti-mouse Ig antibody, has been studied by immunofluorescence, using fluorescein conjugated Con A and rhodamine-conjugated anti-mouse Ig antibody, and by electron microscopy, using native or fluorescein-conjugated Con A and ferritin-conjugated anti-mouse Ig antibody. Prior incubation of the cells with Con A inhibited only partially capping os surface Ig, whereas it blocked almost completely capping of theta antigens. Both on cells with rings and on cells with caps the staining for surface Ig or theta antigen was superimposed to the staining for Con A. When Con A receptors on spleen cells were capped by Con A at concentrations of 10 mug/ml or higher, and the distribution of surface Ig was examined under noncapping conditions, all detectable surface Ig were found in the caps. As shown by electron microscopy, surface Ig remained dispersed in a layer of Con A. The ability of Con A to cap surface Ig was not altered by the presence of cohchicine or vinblastine. These results suggest that surface Ig are cross-linked by Con A to other Con A receptors. In these conditions surface Ig behave essentially as Con A receptors, as for example, in their sensitivity to cytochalasin B during inhibition or reversal of capping induced by this drug. The behavior of surface Ig parallels that of Con A receptors also in the presence of vinblastine. It is concluded that in the presence of Con A, antimitotic drugs do not modify directly the interaction between Con A receptors and surface Ig, but probably influence the capping ability of the Con A receptors or, more in general, affect the ability to elicit movements over the cell surface. The role in capping of cytochalasin-sensitive and vinblastine-sensitive structures is discussed. Both types of structures appear to play an active role in the formation of a cap, although the former probably corresponds to the main mechanical system responsible for the active displacement of cytoplasmic and surface material.

Ultrastructural and chemical evidences of heterogeneity and hormone dependence of certain glycocalyces

1978 ◽  
Vol 36 (2) ◽  
pp. 322-323
Author(s):  
B. Monis ◽  
D. Lis ◽  
I. Parlanti ◽  
A. R. Eynard ◽  
M. A. Valentich ◽  
...  
Keyword(s):  
Guinea Pig ◽  
Concanavalin A ◽  
Ruthenium Red ◽  
Transitional Epithelium ◽  
Membrane Material ◽  
Hormone Dependence ◽  
Cellulose Acetate Electrophoresis ◽  
Electrophoretic Data ◽  
Fat Globule ◽  
Collecting Tubules

We are gathering evidences which indicate ultrastructural variations and chemical heterogeneity of certain glycocalyces as well as hormone dependence of some of them. Thus, in the lumenal glycocalyx of renal collecting tubules of the guinea-pig granular and filamentous structures were seen (1, fig. 1). By isolation, chemical analysis and cellulose acetate electrophoresis in various buffers of tubular membrane material, glycopeptides and glycosaminoglycans were identified (fig. 2).Guinea-pig and rat transitional epithelium of urinary tract showed a filamentous lumenal glycocalyx demonstrable with ruthenium red (fig. 3) but which only in part stained with concanavalin A. Chemical and electrophoretic data indicated that urothelium contains glycoproteins, glycosaminoglycans and glycolipids.The glycocalyx of the fat globule membrane of milk of several species has a granular appearance as shown by cationic dyes and by concanavalin A (2, 3, fig. 4 and 5). Also, several glycoproteins were isolated and identified on polyacrilamide gel electrophoresis (fig. 6). Glycosaminoglycans and certain glycolipids such as sulfatides were chemically identified in this glycocalyx.

Cyclic AMP-Elevating Agents Inhibit Proliferation of Keratinizing Guinea Pig Epidermal Cells

1974 ◽  
Vol 2 (6) ◽  
pp. 343-350 ◽  
Author(s):  
C. Delescluse ◽  
N.H. Colburn ◽  
E.A. Duell ◽  
J.J. Voorhees
Keyword(s):  
Cyclic Amp ◽  
Guinea Pig ◽  
Epidermal Cells

Changes in lectin-mediated agglutinability during primary embryonic induction in the amphibian embryo

Development ◽  
1980 ◽  
Vol 57 (1) ◽  
pp. 95-106
Author(s):  
Francisco D. Barbieri ◽  
Sara S. Sánchez ◽  
Enrique J. Del Pino
Keyword(s):  
Cell Surface ◽  
Concanavalin A ◽  
Cytochalasin B ◽  
The Other ◽  
Embryonic Induction ◽  
Potassium Oxalate ◽  
Amphibian Embryo ◽  
Structural Alterations ◽  
Significant Difference ◽  
Primary Embryonic Induction

The present study was undertaken to investigate structural alterations at the surfaceof presumptive neural cells after primary embryonic induction. For this purpose, plant lectinmediated agglutinability of dissociated cells from the epiblast of Bufo arenarum gastrulae was tested. Two fragments of epiblast were excised from the same mid-gastrula: one from the dorsal side of the egg, making contact with the invaginating chordamesoblast and assumed to be composed of determined cells and the other from the ventral region of the egg, facing the blastocoele cavity and assumed to be composed of undetermined cells. Cells of the pooled fragments were dissociated in calcium-free Holtfreter's solution with potassium oxalate and incubated in the presence of different concentrations of phytohemagglutinin and concanavalin A. Epiblast cells overlying the archenteron roof are less agglutinated with both lectins than undetermined cells. On the other hand, when egg fragments were removed from the dorsal and ventral regions of early gastrulae before the archenteron was formed, no significant difference in lectin-mediated agglutinability was observed, even after having been cultured in vitro in absence of inducing tissue. These results suggest that the target of the inducing signal generated in the mesoblast is likely to be located on the surface of epiblast cells. Additional experiments showed that cells pretreated with colchicine, cytochalasin B or colchicine and cytochalasin B simultaneously exhibit no significant variation in agglutinability, suggesting that the cytoskeleton was not be involved in the cell surface alteration here described. Treatment of whole embryos or sandwich explants with concanavalin A or phytohemagglutinin has no effect on neural tube formation, suggesting that the carbohydratecontaining binding sites for these lectins are not involved in primary embryonic induction. Changes in cell agglutinability described in this paper are to be interpreted thus as a secondary expression of structural alterations in the cell surface concomitant with neural determination.

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