scholarly journals An analysis of lectin-initiated cell agglutination in a series of CHO subclones which respond morphologically to growth in dibutyryl cyclic AMP.

1976 ◽  
Vol 70 (1) ◽  
pp. 204-216 ◽  
Author(s):  
J van Veen ◽  
R M Roberts ◽  
K D Noonan
Keyword(s):  
Surface Membrane ◽  
Con A ◽  
Cell Agglutination ◽  
Lectin Receptors ◽  
Lectin Receptor ◽  
Free Mobility ◽  
Receptor Sites ◽  
Protein And Rna Synthesis ◽  
A Cell ◽  
Membrane Components

We have investigated the molecular basis of the agglutinability of CHO subclones which respond differentially in terms of morphology and surface architecture in the presence of dB-cAMP in the medium. We have demonstrated that the agglutinability of these subclones with both wheat germ agglutinin (WGA) and concanavalin A (Con A) probably depends on the free lateral mobility of the lectin receptor sites in the plane of the membrane. The nonagglutinable surface architecture seems to depend on the presence in the membrane of a protease-labile peptide(s), which appears to be distinct from the lectin receptors, as well as on continuous protein and RNA synthesis. This dependence on continuous transcription and translation may be related to the maintenance of the protease-labile peptide(s) in such a state as to restrict mobility of the lectin receptors. The surface architecture defined as nonagglutinable also depends on the state of polymerization of the intracellular microtubules and microfilaments. It is suggested that these microskeletal elements serve to anchor the lectin receptors in such a manner as to restrict their mobility and thereby reduce the relative agglutinability of a cell line. We suggest that control of the free mobility of both the Con A and WGA receptor sites is dependent on two constraints, one applied by protease-labile ("surface") membrane components and the other by components of the intracellular microskeletal system.

Detection of Concannavalin a Receptors in Trophozoites and Cysts of Acanthamoeba sp. (W4) Philippine Isolate

1997 ◽  
Vol 3 (S2) ◽  
pp. 119-120
Author(s):  
A.M. Argayosa ◽  
F.F. Natividad ◽  
R.R. Matias ◽  
G.L. Enriquez
Keyword(s):  
Plasma Membrane ◽  
Cell Adhesion ◽  
Con A ◽  
Strong Fluorescence ◽  
Lectin Receptors ◽  
Lectin Receptor ◽  
Adhesion Sites ◽  
Receptor Sites ◽  
Topographical Distribution ◽  
Green Fluorescent

Distribution of glucose and mannose moieties of Acanthamoeba sp. (W4) Philippine isolate was detected using fluorescem isothiocyanate (FITC)- labeled Concannavalin A (Con A) lectin. Green fluorescent patches around the plasma membrane of agglutinated trophozoites (Fig.1) were observed. Isolated Acanthamoeba cyst exhibited strong fluorescence on the cyst wall Brighter fluorescence was detected on the site of adherence between the Acanthamoeba (W4) cysts and trophozoites (Fig. 1,3). These lectin receptors were concentrated at the uroidal region of the trophozoite. The fluorescence, however, was absent in the newly forming hyaline cap (Fig.4). Upon addition of α -methyl-mannoside (0.5 M), Con A binding to sugar moieties in cyst and trophozoites was blocked and no fluorescence was observed.The binding specificity of Con A-FITC and Acanthamoeba cell surface mannose moieties demonstrate topographical distribution of lectin receptor sites. Ultrastructurally, ferritin-labeled Con A at cell adhesion sites showed clustering of lectin receptors. Occurrence of fluorescence in Naegleria sp. using Con A-FITC has been shown to concentrate at the uroidal region but no fluorescence was seen at the anterior of newly formed pseudopodia.

scholarly journals Metastatic potential severely altered by changes in tumor cell adhesiveness and cell-surface sialylation.

1983 ◽  
Vol 157 (1) ◽  
pp. 371-376 ◽  
Author(s):  
M Fogel ◽  
P Altevogt ◽  
V Schirrmacher
Keyword(s):  
Sialic Acid ◽  
Cell Surface ◽  
Tumor Cell ◽  
Metastatic Potential ◽  
Lectin Receptors ◽  
Lectin Receptor ◽  
Receptor Sites ◽  
Variant Line

A plastic adherent variant line (ESb-M) of a highly invasive and metastatic murine T cell lymphoma (ESb) was found to have lost its metastatic potential while still being tumorigenic in normal syngeneic hosts. The variant retained most of its ESb-derived antigenic and biochemical characteristics but differed at binding sites for certain lectins with specificity for terminal N-acetylgalactosamine residues. Whereas such sites were masked by sialic acid on metastatic ESb cells, they became unmasked on the adherent variant line. Metastatic revertants of ESb-M cells did not express the respective lectin receptor sites because these were again masked by sialic acid. It is suggested that the masking of specific lectin receptors sites on the tumor cell surface is of crucial importance for metastatis. If freely exposed, these sites may change adherence characteristics of the cells possibly not only in vitro (to plastic) but also in vivo.

Lectin receptor sites on rat liver cell nuclear membranes

1976 ◽  
Vol 22 (2) ◽  
pp. 335-344
Author(s):  
I. Virtanen ◽  
J. Wartiovaara
Keyword(s):  
Rat Liver ◽  
Liver Cell ◽  
Liver Cells ◽  
Nuclear Surface ◽  
Con A ◽  
Lectin Receptor ◽  
Nuclear Membranes ◽  
Cytoplasmic Surface ◽  
Receptor Sites ◽  
Rat Liver Cells

The presence and localization of lectin receptor sites on rat liver cell nuclear and other endomembranes was studied by light and electron microscopy using fluorescein and ferritin-coupled lectin conjugates. Isolated nuclei labelled with fluorescein-conjugated Concanavalin A (Con A) or wheat germ agglutinin (WGA) often showed membrane staining, which sometimes was especially bright on small stretches of the nuclear surface. Unlabelled nuclei and nuclei with a complete ring fluorescence were also seen. The nuclear fluorescence corresponded in intensity to that seen on the surface of isolated rat liver cells. Con A-ferritin particles were seldom detected on the cytoplasmic surface of the intact nuclear envelope. However, at places where the 2 leaflets of the envelope were widely separated or where the outer nuclear membrane was partly torn away, heavy labelling was seen on the cisternal surface of both the inner and outer nuclear membranes. Labelling with Con A-ferritin was also found on the cisternal side of rough endoplasmic reticulum present in the specimens. No labelling was seen on the cytoplasmic surface of mitochondrial outer membrane. The results demonstrate the presence of binding sites for Con A and WGA in nuclei and an asymmetric localization of these sites on the cisternal side of ribosome-carrying endomembranes in rat liver cells.

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 STUDIES ON THE PHYSIOLOGICAL EFFECTS OF NON-POLAR-POLAR ORGANIC ELECTROLYTES

1947 ◽  
Vol 30 (5) ◽  
pp. 389-397 ◽  
Author(s):  
Rudolf Höber
Keyword(s):  
Organic Anion ◽  
Surface Membrane ◽  
Resting Potential ◽  
Detergent Solution ◽  
Surrounding Water ◽  
Alkyl Radicals ◽  
Reversible Potential ◽  
A Cell ◽  
Strong Attachment ◽  
Membrane Components

1. The commonly used detergents have a poisonous effect, which is due to the non-polar-polar configuration of their organic anion. The non-polar organophilic half of the ion is built up by a long chain of alkyl radicals (8 to 18 carbon atoms), the polar hydrophilic half by a sulfonate or sulfate. If brought into contact with the organic surface membrane of a cell, this structure, due to the strong attachment of the alkyl chains to its surface, and due to the pull of the hydrophilic part towards the surrounding water, is subjected to a heavy stress terminating in tearing to pieces the membrane (by denaturing and loosening the membrane components; bacteriolysis, cytolysis). Correspondingly, with frog muscle, one end of which has been treated with the detergent solution, an irreversible negative injury potential is produced. 2. Applying, instead, the compounds bearing short chains of alkyl radicals (1 to 6 carbon atoms), producing less stress on the membrane and correspondingly a slighter derangement of its architecture, a reversible positive resting potential appears. This is interpreted to be the effect of the non-polar part of the anion, which, due to its surface activity, intrudes into the pores of the membranes, notwithstanding the negative charge of their walls. 3. The short chained detergents seem to be replaceable by various organic "semidetergents," the organophilic behavior of their anion being represented by a slight chemical affinity (NH2), the hydrophilic by the effect of a carboxyl group (COO) instead of sulfate or sulfonate. The effect of the semidetergents on muscle is a positive reversible potential. Their physiological significance may be visualized as a functional activation.

The organization of cell surface membrane domains

1989 ◽  
Vol 47 ◽  
pp. 804-805
Author(s):  
Michael Edidin
Keyword(s):  
Cell Surface ◽  
Membrane Lipids ◽  
Surface Membrane ◽  
Lateral Diffusion ◽  
Cell Types ◽  
Membrane Domains ◽  
Membrane Biology ◽  
Morphological Polarity ◽  
Discrete Domains ◽  
Membrane Components

Cell surface membranes are based on a fluid lipid bilayer and models of the membranes' organization have emphasised the possibilities for lateral motion of membrane lipids and proteins within the bilayer. Two recent trends in cell and membrane biology make us consider ways in which membrane organization works against its inherent fluidity, localizing both lipids and proteins into discrete domains. There is evidence for such domains, even in cells without obvious morphological polarity and organization [Table 1]. Cells that are morphologically polarised, for example epithelial cells, raise the issue of membrane domains in an accute form.The technique of fluorescence photobleaching and recovery, FPR, was developed to measure lateral diffusion of membrane components. It has also proven to be a powerful tool for the analysis of constraints to lateral mobility. FPR resolves several sorts of membrane domains, all on the micrometer scale, in several different cell types.

Modification of fibroblast surface amines alters receptor-mediated cell spreading on protein-coated substrata but not adsorptive endocytosis

1981 ◽  
Vol 49 (1) ◽  
pp. 283-297
Author(s):  
J.D. Aplin ◽  
R.C. Hughes
Keyword(s):  
Cell Attachment ◽  
Surface Membrane ◽  
Fluorescein Isothiocyanate ◽  
Adhesive Interaction ◽  
Cultured Fibroblasts ◽  
Amine Groups ◽  
Coated Surfaces ◽  
Amine Compounds ◽  
Membrane Components ◽  
Dose Dependent

Fluorescein isothiocyanate (FITC) and other anionic reagents specific for amine groups have previously been shown to inhibit the adhesion and spreading of cultured fibroblasts to fibronectin-coated surfaces (Butters, Devalia, Aplin & Hughes, 1980). Here it is demonstrated that a population of FITC-labelled cells can be separated using flow cytometry into fractions displaying greater and lesser adhesivity at lower and higher fluorescence, respectively, demonstrating that the inhibition is dose-dependent. Glass coverslips covalently derivatized with the lectins ricin and concanavalin A are used to show that the inhibition also occurs in lectinmediated cell adhesion as well as in adhesion to collagen coated with fibronectin and plastic coated with serum or antibody, suggesting that all of these responses share a common, FITC-sensitive component. Simple primary amine compounds inhibit adhesion to fibronectin, but specific inhibitors of transglutaminases do not affect the process. Transglutaminase activity of cell surfaces has been implicated in protein endocytosis and receptor recycling (Davies et al. 1980). FITC modification of cells appears to affect specifically adhesive interaction, since ricin cytotoxicity and infection of cells with influenza and Sendai viruses (phenomena thought to proceed by means of receptor-mediated endocytosis) are unaffected. Evidently, receptor-mediated cell attachment, spreading on protein-coated surfaces and protein endocytosis are functionally separate events requiring different cell-surface membrane components, even when the same protein (ricin) is used to trigger these 2 processes.

scholarly journals MICRURGICAL STUDIES IN CELL PHYSIOLOGY

1926 ◽  
Vol 10 (1) ◽  
pp. 9-21 ◽  
Author(s):  
Paul Reznikoff
Keyword(s):  
Heavy Metals ◽  
Metal Cation ◽  
Surface Membrane ◽  
The Other ◽  
Contractile Vacuole ◽  
Toxic Action ◽  
Cell Physiology ◽  
Relative Toxicity ◽  
A Cell

I. Plasmalemma. 1. The order of toxicity of the salts used in these experiments on the surface membrane of a cell, taking as a criterion viability of amebæ immersed in solutions for 1 day, is HgCl2, FeCl3> AlCl3> CuCl2> PbCl2> FeCl2. Using viability for 5 days as a criterion, the order of toxicity is PbCl2> CuCl2> HgCl2> AlCl3> FeCl3> FeCl2. 2. The rate of toxicity is in the order FeCl3> HgCl2> AlCl3> FeCl2> CuCl2> PbCl2. 3. The ability of amebæ to recover from a marked tear of the plasmalemma in the solutions of the salts occurred in the following order: AlCl3> PbCl2> FeCl2> CuCl2> FeCl3> HgCl2. II. Internal Protoplasm. 4. The relative toxicity of the salts on the internal protoplasm, judged by the recovery of the amebæ from large injections and the range over which these salts can cause coagulation of the internal protoplasm, is in the following order: PbCl2> CuCl2> FeCl3> HgCl2> FeCl2> AlCl3. 5. AlCl3 in concentrations between M/32 and M/250 causes a marked temporary enlargement of the contractile vacuole. FeCl2, FeCl3, and CuCl3 produce a slight enlargement of the vacuole. 6. PbCl2, in concentrations used in these experiments, appears to form a different type of combination with the internal protoplasm than do the other salts. III. Permeability. 7. Using the similarity in appearance of the internal protoplasm after injection and after immersion to indicate that the surface is permeable to a substance in which the ameba is immersed, it is concluded that AlCl3 can easily penetrate the intact plasmalemma. CuCl2 also seems to have some penetrating power. None of the other salts studied give visible internal evidence of penetrability into the ameba. IV. Toxicity. 8. The toxic action of the chlorides of the heavy metals used in these experiments, and of aluminum, is exerted principally upon the surface of the cell and is due not only to the action of the metal cation but also to acid which is produced by hydrolysis.

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