Concanavalin A binding to amphibian embryo and effect on morphogenesis

Development ◽  
1979 ◽  
Vol 51 (1) ◽  
pp. 63-72
Author(s):  
J. C. Boucaut ◽  
B. Bernard ◽  
M. Aubery ◽  
R. Bourrillon ◽  
Ch. Houillon
Keyword(s):  
Concanavalin A ◽  
Direct Interaction ◽  
Fluorescein Isothiocyanate ◽  
Inhibitory Effect ◽  
Vitelline Membrane ◽  
Con A ◽  
Amphibian Embryo ◽  
Before And After ◽  
Three Stages ◽  
Pleurodeles Waltlii

The effect of Concanavalin A (Con A) on morphogenesis in Pleurodeles waltlii has been studied. Embryos were incubated with various concentrations of the lectin for a period of 6 days. Three stages of development were examined, late blastula, young gastrula and late gastrula. In the presence of the lectin at a concentration of 200, 150 or 100 μg/ml morphogenic movements were delayed, altered and finally blocked. At lower concentrations, 50 or 25 μg/ml, there was a slight delay in gastrulation, but in some cases development was normal. These findings indicate that Con A exerted an inhibitory effect on amphibian morphogenesis and there is evidence that the lectin effect was concentration dependent. The effects of Con A were specific since they were totally inhibited by α-methyl-D-mannopyranoside (0·05 m). The viability of the 24 h lectin-treated embryos was demonstrated by washing experiments. Labelled Con A binding to the embryos was investigated before and after discarding the vitelline membrane. The results suggest a direct interaction between Con A and the cell surface and this was confirmed by using fluorescein isothiocyanate Con A.

Inversion in Volvox tertius: the effects of con A

1981 ◽  
Vol 48 (1) ◽  
pp. 355-366
Author(s):  
G.W. Ireland ◽  
S.E. Hawkins
Keyword(s):  
Cell Division ◽  
Cell Shape ◽  
Shape Change ◽  
Fluorescein Isothiocyanate ◽  
Inhibitory Effect ◽  
Con A ◽  
Cell Shape Change ◽  
Enhanced Production ◽  
Inside Out

During the development of Volvox tertius spheroids, a single-celled gonidium enlarges and undergoes multiple incomplete cleavages to give an embryo which is ‘inside-out’ with respect to the adult organism. A morphogenetic movement, termed ‘inversion’, turns this hollow ball of cells ‘inside-out’ through a hole, the phialopore. In V. tertius this phialopore possesses 4 inwardly directed lips. Normal inversion was studied in vitro in slide chambers and involved cell-shape changes accompanied by the production of pseudopodia and the bending backwards of the phialopore lips. 100 micrograms/ml Con A specifically and reversibly blocked inversion. Despite the inhibitory effect on cell division, the blocking of inversion was not due to the blocking of the last cell division some 50–100 min prior to inversion. Neither did the first cell-shape change from pear- to spindle-shape appear blocked. A feature of inhibition by Con A was the enhanced production of pseudopodia by embryos blocked at inversion, and the abnormal production of pseudopodia by embryos blocked at earlier stages. Non-inverting embryos showed internal flagella. We suggest that the Con A block to inversion, which may be reversed by alpha-methyl mannoside, arises from the prevention of backwards-bending of the phialopore lips. Fluorescein-isothiocyanate-Con A bound to embryo and cell coat, ane more strongly to the embryo at pre-inversion. SDS-polyacrylamide gel analysis of proteins isolated from embryos showed 4 glycoprotein bands, but Con A binding to these bands could not be demonstrated.

scholarly journals FACTORS AFFECTING THE REDISTRIBUTION OF SURFACE-BOUND CONCANAVALIN A ON HUMAN POLYMORPHONUCLEAR LEUKOCYTES

1974 ◽  
Vol 62 (2) ◽  
pp. 351-365 ◽  
Author(s):  
Graeme B. Ryan ◽  
Joan Z. Borysenko ◽  
Morris J. Karnovsky
Keyword(s):  
Concanavalin A ◽  
Polymorphonuclear Leukocytes ◽  
Cytochalasin B ◽  
Immobilized Cells ◽  
Fluorescein Isothiocyanate ◽  
Cross Linking ◽  
Con A ◽  
Factors Affecting ◽  
Motile Cells ◽  
Cellular Locomotion

Human neutrophil polymorphonuclear leukocytes (PMN) were studied to determine the influence of cellular locomotion upon the redistribution and capping of concanavalin A (Con A). Con A was detected by fluorescence (using Con A conjugated to fluorescein isothiocyanate [Con A-FITC]), or on shadow-cast replicas (using Busycon canaliculatum hemocyanin as a marker for Con A). After labeling with Con A 100 µg/ml at 4°C and warming to 37°C, locomotion occurred, and the Con A quickly aggregated into a cap at the trailing end of the cell. When locomotion was inhibited (with cytochalasin B, or by incubation in serum-free medium at 18°C) Con A rapidly formed a cap over the central region of the cell. Iodoacetamide inhibited capping. PMN labeled with FITC, a monovalent ligand, developed caps at the tail only on motile cells; FITC remained dispersed on immobilized cells. PMN exposed to Con A 100 µg/ml at 37°C bound more lectin than at 4°C, became immobilized, and showed slow central capping. The Con A soon became internalized to form a perinuclear ring. Such treatment in the presence of cytochalasin B resulted in the quick formation of persistent central caps. Colchicine (or prior cooling) protected PMN from the immobilizing effect of Con A, and tail caps were found on 30–40% of cells. Immobilization of colchicine-treated cells caused Con A to remain in dispersed clusters. Thus, capping on PMN is a temperature- and energy-dependent process that proceeds independently of cellular locomotion, provided a colchicine-sensitive system is intact and the ligand is capable of cross linking receptors. On the other hand, if the cell does move, it appears that ligands may be swept into a cap at the tail whether cross-linking occurs or not.

scholarly journals Transmembrane linkage between surface glycoproteins and components of the cytoplasm in neutrophil leukocytes.

1981 ◽  
Vol 90 (3) ◽  
pp. 743-754 ◽  
Author(s):  
P Sheterline ◽  
C R Hopkins
Keyword(s):  
Plasma Membrane ◽  
Concanavalin A ◽  
Fluorescein Isothiocyanate ◽  
Total Cell ◽  
Membrane Glycoproteins ◽  
Con A ◽  
Fluorescence And Electron Microscopy ◽  
Nonionic Detergent ◽  
Enzyme Markers ◽  
Neutrophil Leukocytes

An experimental approach is described that enables the analysis of interactions between exogenous surface ligands and components of the cytoplasm in neutrophil leukocytes. Neutrophils treated with the nonionic detergent Lubrol PX, under controlled conditions, yield intact detergent-insoluble ghosts. Morphological analysis of neutrophil ghosts shows that they retain the original dimensions of the cell and consist almost entirely of a peripheral filamentous network, representing the submembranous cortical web, concentric to nuclear remnants. All intracellular membrane-bounded organelles, plasma membrane, and background cytoplasmic electron density are absent. Biochemical analysis of the ghosts shows that less than 10% of enzyme markers for the soluble and granule fractions remain, and that greater than 90% of total cell phospholipid is removed during detergent extraction. The major proteins remaining in the ghosts comigrate, on polyacrylamide gels in the presence of SDS, with chicken gizzard actin, myosin, filamin, and a 110-kdalton protein. Patches and caps induced on neutrophils with either fluorescein isothiocyanate-concanavalin A or ferritin-concanavalin A retain their original location and morphology on ghosts after lysis, as determined by both fluorescence and electron microscopy. In similar experiments, but using 125I-labeled lectins, 37% of total cell bound concanavalin A (Con A) and 25% succinylated Con A remain attached to the ghosts. A major 125I-labeled membrane glycoprotein (80 kdaltons) is associated with ghosts prepared from intact neutrophils iodinated in the presence of exogenous lactoperoxidase. Further 125I-labeled membrane glycoproteins (217, 170, and 147 kdaltons) become associated with ghosts prepared from iodinated cells treated before lysis with Con A, but not with succinylated Con A. These data taken together suggest that linkages exist in neutrophils between proteins exposed on the outer surface of the plasma membrane and the peripheral filamentous network independent of the presence of lipid bilayer. The implications of these findings for surface motile phenomena will be discussed.

scholarly journals Genetic control of lymphocyte activation: lack of response to low doses of concanavalin A in lipopolysaccharide-nonresponder mice

1977 ◽  
Vol 146 (4) ◽  
pp. 1146-1151 ◽  
Author(s):  
PH Bick ◽  
U Persson ◽  
E Smith ◽  
E Moller ◽  
L Hammarstrom
Keyword(s):  
B Cell ◽  
Dose Response ◽  
Concanavalin A ◽  
Single Gene ◽  
Lymphocyte Activation ◽  
Inhibitory Effect ◽  
Low Doses ◽  
Spleen Cells ◽  
Con A ◽  
Protein Locus

C3H/HeJ mice do not respond to the polyclonal B-cell activator lipopolysaccharide (LPS) from Escherichia coli; this was first described by Sultzer who observed that mice of this strain did not respond to an intraperitoneal (i.p.) injection of LPS as measured by the accumulation of leukocytes in the peritoneal cavity. Neither were C3H/HeJ mice as susceptible to LPS toxcitiy (1). It was later reported that LPS-induced mitogenesis (2,3), adjuvanticity (4), and the appearance of Ia antigens on B lymphocytes as induced by LPS, (5) was also absent in C3H/HeJ mice. However, lymphocytes from these mice respond normally to the polyclonal B-cell activators purified protein derivative of tuberculin (2,6) and dextran sulfate and have also been reported to respond normally to concanavalin A (Con A) (2). Furthermore, the immune responses to sheep erythrocytes (7) and soluble thymus-dependent antigens (4) are normal in C3H/HeJ mice. Unresponsiveness to LPS in C3H/HeJ mice has been found to Be due to a defect in a single gene or a set of linked genes (3,8) which has been mapped between the major urinary protein locus and the locus coding for polysyndactyly on chromosome 4. (1) We have reported that injection of LPS into mice of an LPS-responsive strain causes a shift in the Con A dose-response curve of cultured spleen cells, suppressing the low does response (9). Therefore, we tested the Con A proliferative response in cultures of normal or LPS-activated spleen cells from LPS-responder (C3H/Tif) and LPS-nonresponder (C3H/HeJ) mice. We report here that C3H/HeJ spleen cells respond poorly to low concentrations of Con A (0.05-0.1 μg/ml). Injection of LPS 2 days before culture inhibits the response to low doses of Con A in cultures of C3H/Tif spleen cells but has no inhibitory effect on the dose response profile of C3H/HeJ spleen cells. Furthermore, the low dose Con A response of spleen cells is dependent upon the presence of an Ia-positive cell. (2) The role of Ia-positive cells in the Con A response of C3H/Tif and C3H/HeJ spleen cells is described.

Concanavalin A Induces Patching/Capping of the Platelet Membrane Glycoprotein llb/llla Complex

1988 ◽  
Vol 59 (02) ◽  
pp. 281-283 ◽  
Author(s):  
R M Kakaiya ◽  
T L Kiraly ◽  
R G Cable
Keyword(s):  
Molecular Mechanism ◽  
Concanavalin A ◽  
Fluorescein Isothiocyanate ◽  
Platelet Membrane ◽  
Membrane Glycoprotein ◽  
Membrane Glycoproteins ◽  
Con A ◽  
Antibody Preparation ◽  
Platelet Membrane Glycoprotein ◽  
Normal Human

SummaryTwo recent reports have shown platelet patching/capping by concanavalin A (Con A). In these studies, Con A receptors were shown to mobilize from pseudopodia and lamellipodia to the central cell parts during platelet attachment and spreading. The molecular mechanism underlying Con A receptor capping was not examined in either study.Con a binds maximally to human platelet membrane glycoproteins IIb and IIIa. In order to test whether Con A-induced capping caused the capping of this membrane glycoprotein complex, we treated normal human platelets with unlabeled Con A. After fixation, platelets were further treated with mouse monoclonal antibodies against the membrane glycoprotein IIb/IIIa complex and stained with fluorescein isothiocyanate (FITC) tagged anti-mouse IgG. An average of 16% platelets manifested capping with one monoclonal antibody preparation (N = 2) and 12% with a second preparation (N = 2).Control studies showed that only 18% of normal human fresh platelets exhibit capping with FITC-Con A (N = 17). If platelets were first incubated with unlabeled Con A, followed by staining with FITC-labeled anti-Con A antibody, an average of 15% platelets manifested caps (N = 17). Capping was inhibited by methyl-alpha-D-mannopyranoside (a known inhibitor of Con A), at cold temperature and by pre-treatment of platelets with colchicine.Our studies confirm the earlier findings on Con A induced capping. Also, our findings suggest that the molecular mechanism for Con A receptor capping involves patching and capping of the platelet membrane glycoprotein IIb/IIIa complex. It is possible that glycoprotein Ilb/IIIa redistribution might be intimately involved during platelet attachment and spreading.

scholarly journals Identification of concanavalin A receptors and galactose-binding proteins in purified plasma membranes of Dictyostelium discoideum.

1977 ◽  
Vol 74 (1) ◽  
pp. 264-273 ◽  
Author(s):  
C M West ◽  
D McMahon
Keyword(s):  
Dictyostelium Discoideum ◽  
Concanavalin A ◽  
Plasma Membranes ◽  
Sodium Dodecyl ◽  
Fluorescein Isothiocyanate ◽  
Binding Activity ◽  
Cellular Slime Mold ◽  
Con A ◽  
Stage Of Development ◽  
Cellular Slime

Two techniques have been modified to provide simple means for the identification of molecules which bind concanavalin A (Con A). Crossed immunoelectrophoresis was altered by replacing antibody with Con A, and receptors were identified by the precipitin arcs which they produced. Con A, tagged with fluorescein isothiocyanate, was also diffused into prefixed sodium dodecyl sulfate (SDS)-polyacrylamide gels, and additional receptors identified by fluorescence. More than 35 molecules in the plasma membranes of the cellular slime mold Dictyostelium discoideum which bind Con A were identified with these techniques. At least 12 of these diminish and 12 increase in importance as receptors during differentiation of the cells from the vegetative to the preculmination stage of development. In the course of these experiments, it was possible to confirm the presence of the galactose-binding protein discoidin, in the plasma membrane, by electrophoresing membrane proteins into an agarose gel. This lectin regains its sugar-binding activity after denaturation and electrophoresis in SDS.

scholarly journals Inhibitory Effect of Hydroxymethylfurfural in Viability of BALB/C Mice Splenocytes

2019 ◽  
Vol 25 (1) ◽  
pp. 31-36
Author(s):  
Sevda Saleh-Ghadimi ◽  
Hamed Jafari-Vayghan ◽  
Sorayya Kheirouri ◽  
Mohammad Alizadeh
Keyword(s):  
Cell Proliferation ◽  
Dna Damage ◽  
T Cells ◽  
B Cells ◽  
Concanavalin A ◽  
Untreated Control ◽  
Inhibitory Effect ◽  
Spleen Cells ◽  
Con A ◽  
Significant Difference

Background: This study was designed to discover if hydroxymethylfurfural (HMF) exposure modifies cell proliferation and DNA damage in BALB/c mice splenocytes. Methods: Mitogenesis in T cells and B cells was induced by Concanavalin A (Con A) and lipopolysaccharide (LPS). The colorimetric tetrazolium assay was used to evaluate cell proliferation. DNA damaging consequences were evaluated via measurement of 8-hydroxy-2-deoxyguanosine (8-OHdG) level in BALB/c mice splenocytes. Results: Spleen cells proliferation elicited by ConA, was dramatically suppressed by 25, 50 and 100 mM of HMF. However, there was not any significant difference between various concentrations of HMF. The same result was observed following treatment with LPS and HMF in different concentrations. Eight-OHdG concentration was elevated significantly in HMF treated groups compared with untreated control and mitogens. Conclusion: HMF was found to have immunosuppressing and DNA damaging properties in mM concentrations in mice splenocytes.

scholarly journals Emodin Protects Against Concanavalin A-Induced Hepatitis in Mice Through Inhibiting Activation of the p38 MAPK-NF-κB Signaling Pathway

2015 ◽  
Vol 35 (4) ◽  
pp. 1557-1570 ◽  
Author(s):  
Jihua Xue ◽  
Feng Chen ◽  
Jing Wang ◽  
Shanshan Wu ◽  
Min Zheng ◽  
...  
Keyword(s):  
P38 Mapk ◽  
Inflammatory Cytokines ◽  
Concanavalin A ◽  
Molecular Mechanisms ◽  
Hepatic Necrosis ◽  
Con A ◽  
Beneficial Effects ◽  
Cytokines And Chemokines ◽  
Before And After ◽  
Pro Inflammatory Cytokines

Background/Aims: To investigate the effects of emodin on concanavalin A (Con A)-induced hepatitis in mice and to elucidate its underlying molecular mechanisms. Methods: A fulminant hepatitis model was established successfully by the intravenous administration of Con A (20 mg/kg) to male Balb/c mice. Emodin was administered to the mice by gavage before and after Con A injection. The levels of pro-inflammatory cytokines and chemokines, numbers of CD4+ and F4/80+ cells infiltrated into the liver, and amounts of phosphorylated p38 MAPK and NF-γB in mouse livers and RAW264.7 and EL4 cells were measured. Results: Pretreatment with emodin significantly protected the animals from T cell-mediated hepatitis, as shown by the decreased elevations of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST), as well as reduced hepatic necrosis. In addition, emodin pretreatment markedly reduced the intrahepatic expression of pro-inflammatory cytokines and chemokines, including tumor necrosis factor (TNF)-a, interferon (IFN)-γ, interleukin (IL)-1ß, IL-6, IL-12, inducible nitric oxide synthase (iNOS), integrin alpha M (ITGAM), chemokine (C-C motif) ligand 2 (CCL2), macrophage inflammatory protein 2 (MIP-2) and chemokine (CXC motif) receptor 2 (CXCR2). Furthermore, emodin pretreatment dramatically suppressed the numbers of CD4+ and F4/80+ cells infiltrating into the liver as well as the activation of p38 MAPK and NF-γB in Con A-treated mouse livers and RAW264.7 and EL4 cells. Conclusion: The results indicate that emodin pretreatment protects against Con A-induced liver injury in mice; these beneficial effects may occur partially through inhibition of both the infiltration of CD4+ and F4/80+ cells and the activation of the p38 MAPK-NF-γB pathway in CD4+ T cells and macrophages.

Lysolecithin Induced Membrane Alterations in Thymocytes

1975 ◽  
Vol 30 (11-12) ◽  
pp. 785-792 ◽  
Author(s):  
Hans Ulrich Weltzien
Keyword(s):  
Immune Response ◽  
Concanavalin A ◽  
Lectin Binding ◽  
Inhibitory Effect ◽  
Short Chain ◽  
Membrane Properties ◽  
Con A ◽  
Lectin Receptors ◽  
Induced Membrane ◽  
Kinetics Of

Abstract The effects of lysolecithin and of 2 synthetic ether-desoxy lysolecithin analogs, containing alkyl residues of 16 or 12 carbon atoms, on the agglutination kinetics of calf and rabbit thymocytes by concanavalin A (Con A) were investigated. Unlike the natural lysolecithin, these synthetic analogs are resistant to metabolism by membrane associated enzymes. It was found that pretreatment of thymocytes with lysolecithin or with the C16-analog leads to slightly increased agglutination rates. The C12-analog, in contrast, significantly inhibits thymocyte agglutination by Con A. More­ over, a comparison of these results with lysophosphatide effects on the agglutinability of erythrocytes of various species revealed that the inhibitory effect of the short-chain phosphatide is rather specific for thymocytes. The finding that long-and short-chain lysophosphatides, which have previously been shown to react as adjuvants or immunosuppressants, respectively, induce adserve alterations in thymocyte membranes indicates that these substances may affect the immune response by changing the membrane properties of immune competent cells. Concerning the nature of these membrane alterations it was shown that lysolecithin did not affect the number of Con A receptors per cell nor the affinity of lectin binding. It is therefore concluded that the lysophosphatide in­ duced alterations of Con A agglutinability can not be caused by an uncovering or covering of lectin-receptors.

Mobility of concanavalin A receptors and distribution of cytoplasmic actin in odontogenic epithelial and mesenchymal cells

1978 ◽  
Vol 33 (1) ◽  
pp. 329-340
Author(s):  
S.S. Prime ◽  
B.H. Toh
Keyword(s):  
Epithelial Cells ◽  
Concanavalin A ◽  
Cytochalasin B ◽  
Fluorescein Isothiocyanate ◽  
Tooth Germ ◽  
Cell Types ◽  
Mesenchymal Cells ◽  
Staining Procedure ◽  
Con A ◽  
Cytoplasmic Actin

The distribution of concanavalin A (Con A) surface receptors and cytoplasmic actin in the same cell was studied in monolayer cultures of 2 odontogenic epithelial cells of different developmental age and in ecto-mesenchymal cells derived from the same tooth germ. Con A receptors were demonstrated by fluorescein-isothiocyanate-labelled Con A (FITC-Con A) and cytoplasmic actin by a specific anti-actin autoantibody (AAA) traced with a rhodamine-labelled goat anti-human globulin (R-AHG). All 3 cell types, incubated with FITC-Con A at 37 degrees C for increasing time periods, showed progressive changes in staining patterns from clusters, caps to perinuclear globules. Capping was seen in the majority of immature epithelial cells at 120–180 min, in cells of more mature epithelium at 180–240 min and in ecto-mesenchymal cells at 240–360 min. Binding of FITC-Con A to cell surfaces resulted in sequential changes in AAA staining from filamentous to an aggregated or diffuse pattern, co-capping of aggregated or diffusely stained areas with those capped by FITC-Con A, presence of aggregated or diffusely stained areas in sites similar to the perinuclear globules stained by FITC-Con A, to final re-emergence of filamentous staining. Prior treatment of cells with cytochalasin B or colchicine promoted capping in epithelial but not in ecto-mesenchymal cells while presence of either drug throughout the staining procedure inhibited capping. The results show that Con A receptors are more mobile in epithelial compared to ecto-mesenchymal cells and in immature epithelial cells compared to their more mature counterparts, and that binding and mobility of Con A receptors on the cell surface is associated with redistribution of cytoplasmic actin. The cytochalasin B and colchicine experiments suggest that both microfilaments and microtubules may have synergistic roles in the opposing functions of receptor anchorage and mobility, and that the relative receptor immobility of ectomesenchymal compared to epithelial cells may be attributed to firmer receptor anchorage to the cytoskeleton.

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