scholarly journals Surface morphology and agglutinability with concanavalin A in normal and transformed murine fibroblasts.

1976 ◽  
Vol 68 (1) ◽  
pp. 101-112 ◽  
Author(s):  
J G Collard ◽  
J H Temmink
Keyword(s):  
Surface Morphology ◽  
Concanavalin A ◽  
Ethylenediaminetetraacetic Acid ◽  
Simian Virus 40 ◽  
Cell Surfaces ◽  
3T3 Cells ◽  
Con A ◽  
Transformed Fibroblasts ◽  
Murine Fibroblasts

The surface morphology of attached and suspended normal and transformed fibroblasts has been studied with the scanning electron microscope. Normal murine fibroblasts (3T3) grow in vitro with widely extended leading lamellae. During most parts of the cell cycle the surfaces of these cells are practically free of microvilli. When the cells round up for mitosis, their cell surfaces become adorned with many microvilli. In contrast, simian virus 40-transformed fibroblasts (SV3T3) grow more compact, and their cell surfaces remain smooth throughout the life cycle. When confluent 3T3 and SV3T3 cells are suspended with ethylenediaminetetraacetic acid (EDTA) for agglutination assays, similar differences in surface morphology are found: 3T3 cells always bear many microvilli, whereas most SV3T3 cells are essentially free of microvilli. The addition of concanavalin A (Con A) does not influence the surface morphology of the suspended cells. The morphological differences described here may be important for the agglutination process of the normal and transformed 3T3 cells, because they affect the real cell surface area and thus the density of Con A-binding sites.

Differences in density of Concanavalin A-binding sites due to differences in surface morphology of suspended normal and transformed 3T3 fibroblasts

1975 ◽  
Vol 19 (1) ◽  
pp. 21-32
Author(s):  
J.G. Collard ◽  
J.H. Temmink
Keyword(s):  
Surface Morphology ◽  
Concanavalin A ◽  
Binding Sites ◽  
3T3 Cells ◽  
Con A ◽  
3T3 Fibroblasts ◽  
Transformed Fibroblasts ◽  
Transmission Electron ◽  
The Difference ◽  
Electron Microscopes

Calculations of the density of Concanavalin A (Con A)-binding sites on normal and transformed fibroblasts have, as yet, been based on the unproven assumption that suspended cells are smooth spheres. We studied the surface morphology of suspended normal and transformed fibroblasts with scanning and transmission electron microscopes, and found a large difference in surface morphology between suspended normal and transformed 3T3 cells. When this difference in surface morphology was taken into account, the estimated cell surface area of normal 3T3 cells was approximately seven times larger than that of transformed 3T3 cells. Since equal numbers of 3H-Con A molecules are bound on normal and transformed cells, the density of Con A-binding sites is approximately seven times greater on transformed than on normal 3T3 cells. The difference in density of Con A-binding sites between normal and transformed fibroblasts might be sufficient to explain the difference in agglutination response, as originally suggested by Burger, and may also be the cause of the different degrees of clustering of Con A-binding sites on the plasma membrane of these cells.

Partial purification and characterization of cysteine proteinases in eccrine sweat

1987 ◽  
Vol 252 (6) ◽  
pp. R1119-R1129
Author(s):  
H. Yokozeki ◽  
T. Hibino ◽  
K. Sato
Keyword(s):  
Concanavalin A ◽  
Cathepsin B ◽  
Ethylenediaminetetraacetic Acid ◽  
Sweat Glands ◽  
Partial Purification ◽  
Aminopeptidase Activity ◽  
Specific Substrate ◽  
Cysteine Proteinases ◽  
Eccrine Sweat

Attempts were made to purify and characterize cysteine proteinases in human eccrine sweat and further clarify their origin. Benzoyl-DL-arginine-beta-naphthylamide (BANA) and L-leucine beta-naphthylamide (LeuNA) hydrolases in thermally induced sweat were sequentially purified by Sephacryl S-200 chromatography and chromatofocusing, which yielded two major peaks of BANA hydrolase activity, BANA-I and BANA-II. Both enzymes are cysteine proteinases as evidenced by stimulation of enzymic activity by dithiothreitol and ethylenediaminetetraacetic acid and its inhibition by iodoacetic acid, (PCMB), and trans-epoxysuccinyl-L-leucylamido-(4-guanidino)-butane (E-64). Unlike BANA-II, BANA-I showed an additional aminopeptidase activity, an affinity to concanavalin A-Sepharose but no affinity to organomercurial sepharose and failed to hydrolyze benzyloxycarbonyl-phenylalanyl-arginine 4-methyl 7-coumarylamide (Z-Phe-Arg-NMec), a specific substrate for cathepsin B, which is poorly sensitive to leupeptin [inhibitor constant (Ki) = 1 X 10(-5) M] and relatively heat resistant. These and other characteristics such as its isoelectric points (PI) (= 5.8) and the Km for Arg-NMec (0.1 mM) and BANA (0.71 mM) all support the possibility that BANA-I is closely related to cathepsin H. In contrast, BANA-II is sensitive to Zn2+, leupeptin (Ki = 5.5 X 10(-9) M), is not adsorbed by concanavalin A- (Con-A)Sepharose, but is bound to organomercurial sepharose. It has a specificity to Z-Phe-Arg-NMec but not to Arg-NMec, has the molecular weight of 27, PI of 5.2, the pH optima for BANA (6.0), and the Km for BANA of 3.3 mM and the Km for Z-Phe-Arg-NMec of 0.1 mM. These features resemble those of liver cathepsin B. Leupeptin-sensitive BANA hydrolase was observed in the glandular extract of isolated sweat glands, which was increased after stimulation with methacholine and isoproterenol in vitro. The data are consistent with the notion that cathepsins B- and H-like enzymes are present in eccrine sweat and the former may be derived from the sweat gland.

scholarly journals Antagonism by dibutyryl adenosine cyclic 3',5'-monophosphate and testololactone of concanavalin A capping.

1975 ◽  
Vol 66 (2) ◽  
pp. 392-403 ◽  
Author(s):  
B Storrie
Keyword(s):  
Concanavalin A ◽  
Binding Sites ◽  
Cytochalasin B ◽  
Cold Treatment ◽  
Intracellular Camp ◽  
Camp Concentration ◽  
Con A ◽  
Cell Rounding ◽  
Intracellular Camp Concentration

Exposure of CHO-K1 cells in vitro to dibutyryl adenosine cyclic 3',5'-monophosphate (DBcAMP) plus testololactone produces a rapid, reversible antagonism of ligand-induced collection of initially dispersed concanavalin A (Con A) binding sites into a caplike mass. Morphologically, as Con A capping occurs, the cells become less spread and then round completely. With prolonged Con A exposure, cells cultured in either the absence or the presence of DBcAMP plus testololactone cap and round. Capping is blocked by cold treatment and respiratory inhibitors. Colcemid at concentrations greater than 1 muM promotes both Con A capping and cell rounding. Cytochalasin B at similar concentrations inhibits both capping and cell rounding. Treatment of cells with Con A has little effect on intracellular cAMP concentration. Possible mechanisms by which cAMP may modulate the movement of Con A binding sites are discussed.

scholarly journals A C21-Steroidal Glycoside from Cynanchum atratum Attenuates Concanavalin A-Induced Liver Injury in Mice

Molecules ◽  
2019 ◽  
Vol 24 (6) ◽  
pp. 1087 ◽  
Author(s):  
Jian Yang ◽  
Bin Wang ◽  
Chao-feng Zhang ◽  
Xiang-hong Xu ◽  
Mian Zhang
Keyword(s):  
T Lymphocytes ◽  
Concanavalin A ◽  
Underlying Mechanism ◽  
Dependent Manner ◽  
Histopathological Changes ◽  
Con A ◽  
Concentration Dependent Manner ◽  
Steroidal Glycoside ◽  
First Time

Cynatratoside A (CyA) is a C21 Steroidal glycoside with pregnane skeleton isolated from the root of Cynanchum atratum Bunge (Asclepiadaceae). This study aimed to investigate the effects of CyA on concanavalin A (Con A)-induced autoimmune hepatitis (AIH) and the underlying mechanism. CyA was orally administered to mice at 10 and 40 mg/kg 8 h before and 1 h after Con A treatment. The effects of CyA on Con A-induced spleen and liver in mice were assessed via histopathological changes, T lymphocyte amounts and the expressions of IL-1β and ICAM-1. Con A-induced L-02 hepatocytes were used to evaluate whether CyA (0.1–10 μM) can directly protect hepatocytes from cytotoxicity and the possible mechanism. The results revealed that CyA treatment could significantly improve the histopathological changes of spleen and liver, reduce the proliferation of splenic T lymphocytes, and decrease the expressions of IL-1β and ICAM-1 in liver. The experiment in vitro showed that CyA inhibited Con A-induced hepatotoxicity in a concentration-dependent manner. CyA (10 μM) significantly increased/decreased the expression of Bcl-2/Bax and reduced the levels of cleaved caspases-9 and -3. Our study demonstrated for the first time that CyA has a significant protective effect on Con A-induced AIH by inhibiting the activation and adhesion of T lymphocytes and blocking hepatocyte apoptosis.

Effects of the Japanese herbal medicine ‘Inchinko-to’ (TJ-135) on concanavalin A-induced hepatitis in mice

2000 ◽  
Vol 99 (5) ◽  
pp. 421-431 ◽  
Author(s):  
Masayoshi YAMASHIKI ◽  
Akihito MASE ◽  
Ichiro ARAI ◽  
Xian-Xi HUANG ◽  
Tsutomu NOBORI ◽  
...  
Keyword(s):  
Herbal Medicine ◽  
Concanavalin A ◽  
Serum Levels ◽  
Interferon Γ ◽  
Hepatic Necrosis ◽  
Interleukin 12 ◽  
Con A ◽  
Ifn Γ

Inchinko-to (TJ-135) is a herbal medicine consisting of three kinds of crude drugs, and in Japan it is administered mainly to patients with cholestasis. The present study evaluated the effects of TJ-135 on concanavalin A (con A)-induced hepatitis in mice in vivo and con A-induced cytokine production in vitro. When mice were pretreated with oral TJ-135 for 1 week before intravenous con A injection, the activities of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) were significantly decreased 8 h after con A administration (-82%, -96% and -66% respectively). In histological investigations, sub-massive hepatic necrosis accompanying inflammatory cell infiltration was not observed in mice pretreated with TJ-135. Serum levels of interleukin-12 (IL-12), interferon-γ (IFN-γ) and IL-2 were significantly lower in mice pretreated with TJ-135 compared with controls, while IL-10 levels were higher in these mice. Intrasplenic IL-12 levels were significantly lower in mice pretreated with TJ-135, while intrasplenic IL-10 levels were higher in these mice. In vitro, IL-10 production by splenocytes was increased by the addition of TJ-135 to the culture medium, whereas the production of IL-12 and IFN-γ was inhibited. These results suggest that con A-induced hepatitis was ameliorated by pretreatment with TJ-135. With regard to the mechanism of these effects of TJ-135, we speculate that TJ-135 inhibits the production of inflammatory cytokine and enhances the production of anti-inflammatory cytokines. Therefore administration of TJ-135 may be useful in patients with severe acute hepatitis accompanying cholestasis or in those with autoimmune hepatitis.

scholarly journals Isolation of a glycoprotein responsible for the enhanced concanavalin A agglutinability of erythrocytes in Yoshida-ascites-sarcoma-bearing rats: the mechanism of paraneoplastic syndromes

1993 ◽  
Vol 292 (1) ◽  
pp. 163-170 ◽  
Author(s):  
R D Kalraiya ◽  
A Sanjay ◽  
N G Mehta
Keyword(s):  
Molecular Mass ◽  
Concanavalin A ◽  
Paraneoplastic Syndromes ◽  
Host Cells ◽  
Ascites Fluid ◽  
Con A ◽  
Tumour Bearing ◽  
Apparent Homogeneity

As a model for the development of paraneoplastic syndromes, we have studied the mechanism by which erythrocytes in the circulation of rats bearing intraperitoneal Yoshida ascites sarcoma acquire higher agglutinability with concanavalin A (Con A). The in vitro incubation of erythrocytes from normal animals with the cell-free ascites fluid or the plasma of tumour-bearing animals is able to confer an enhanced agglutinability on the cells. Fractionation of the ascites fluid has yielded three subfractions that are active in vitro. Two of these, occurring in small amounts, are a particulate fraction rich in plasma-membrane markers and a soluble fraction containing protein of molecular mass equal to or less than 50 kDa. These two are, however, unable to affect the agglutinability of erythrocytes in vivo, i.e. when injected intraperitoneally into normal rats. The third, and major, fraction consists of proteins of molecular mass equal to or greater than 680 kDa, and is able to modify the erythrocyte agglutinability in vivo. From this fraction, by using a combination of Con A affinity chromatography, gel filtration, (NH4)2SO4 fractionation and DEAE-Sephadex chromatography, an active protein has been purified to apparent homogeneity. It yields a subunit of 310 kDa in the presence of SDS and further breaks down into a polypeptide of 170 kDa when reduced with 2-mercaptoethanol. It has a pI of 5.35. The protein is rich in Glx, and appears to contain hybrid-type N-linked oligosaccharides. The protein is also present in the blood plasma of tumour-bearing, but not normal, rats. The radioiodinated protein binds to the erythrocyte surface adding about 7400 molecules/cell. The study unequivocally demonstrates that a protein from the tumour fluid can appear in the circulation, interact with host cells that are not in contact with the tumour and modify their properties.

scholarly journals Concanavalin-A shows synergistic cytotoxicity with tamoxifen via inducing apoptosis in estrogen receptor-positive breast cancer: In vitro and molecular docking studies

2021 ◽  
Author(s):  
Mohamed Elshal ◽  
Norhan Eid ◽  
Ibrahim El-Sayed ◽  
Wael El-Sayed ◽  
Ahmed Ali Al-Karmalawy
Keyword(s):  
Breast Cancer ◽  
Estrogen Receptor ◽  
Molecular Docking ◽  
Concanavalin A ◽  
Combined Treatment ◽  
Con A ◽  
Synergistic Cytotoxicity ◽  
Mcf 7 ◽  
Positive Breast Cancer

Background: Tamoxifen (TAM) is the main treatment of estrogen receptor (ER)-positive breast cancer, however; its adverse effects and development of resistance hinder its use. Concanavalin A (Con A) is a mannose/glucose-binding lectin that has been reported to induce apoptosis in a variety of cell lines. Methods: Therefore, we aimed to elucidate the effects of Con A on TAM-induced cell death in ERα positive cell line (MCF-7) and to identify the potential underlying molecular mechanisms using in silico and in vitro techniques. Results: Our results demonstrated that combined treatment with Con A and TAM reduced the expression of ERα, which showed clear synergistic effects on inhibiting the cell viability of MCF-7 cells. Interestingly, the combined treatment induces G1 phase arrest and reduces cyclin D1 activity while increasing apoptosis and autophagy as indicated by decreasing the expression level of anti-apoptosis gene BCl-2 and increased apoptosis/autophagic gene BNIP3. Molecular docking was conducted to evaluate the binding affinity of Con A towards ERα, and it revealed its potential activity as an ERα antagonist. Our data further indicated that Con A administration increased the drug reduction index of TAM. Conclusion: Overall, our findings suggested that Con A could be used as an adjuvant agent with TAM to improve its effectiveness as an anticancer agent while minimizing its side effects.

Post-translational regulation of the 54K cellular tumor antigen in normal and transformed cells

1981 ◽  
Vol 1 (2) ◽  
pp. 101-110
Author(s):  
M Oren ◽  
W Maltzman ◽  
A J Levine
Keyword(s):  
Tumor Antigen ◽  
Ribonucleic Acid ◽  
Translational Regulation ◽  
Simian Virus 40 ◽  
T Antigen ◽  
Transformed Cells ◽  
Permissive Temperature ◽  
3T3 Cells ◽  
Messenger Ribonucleic Acid

The 54K cellular tumor antigen has been translated in vitro, using messenger ribonucleic acids from simian virus 40 (SV40)-transformed cells or 3T3 cells. The in vitro 54K product could be immunoprecipitated with SV40 tumor serum and had a peptide map that was similar, but not identical, to the in vivo product. The levels of this 54K protein in SV3T3 cells were significantly higher than those detected in 3T3 cells (D. I. H. Linzer, W. Maltzman, and A. J. Levine, Virology 98:308-318, 1979). In spite of this, the levels of translatable 54K messenger ribonucleic acid from 3T3 and SV3T3 cells were roughly equivalent or often greater in 3T3 cells. Pulse-chase experiments with the 54K protein from 3T3 or SV3T3 cells demonstrated that this protein, once synthesized, was rapidly degraded in 3T3 cells but was extremely stable in SV3T3 cells. Similarly, in an SV40 tsA-transformed cell line, temperature sensitive for the SV40 T-antigen, the 54K protein was rapidly turned over at the nonpermissive temperature and stable at the permissive temperature, whereas the levels of translatable 54K messenger ribonucleic acid at each temperature were roughly equal. These results demonstrate a post-translational regulation of the 54K cellular tumor antigen and suggest that this control is mediated by the SV40 large T-antigen.

scholarly journals Two distinct mechanisms regulate the in vivo generation of cytotoxic T cells.

1982 ◽  
Vol 156 (3) ◽  
pp. 918-923 ◽  
Author(s):  
M S Sy ◽  
S H Lee ◽  
M Tsurufuji ◽  
K L Rock ◽  
B Benacerraf ◽  
...  
Keyword(s):  
T Cells ◽  
T Lymphocytes ◽  
Concanavalin A ◽  
Cytotoxic T Cells ◽  
Cytolytic T Lymphocytes ◽  
Spleen Cells ◽  
Suppressor T Cells ◽  
Con A

Treatment of responder cells with monoclonal anti-Ly-1,2 antibodies plus complement in vitro completely eliminated their ability to generate azobenzenearsonate (ABA)-specific cytolytic T lymphocytes (CTL). However, addition of the concanavalin A-stimulated supernatants of rat spleen cells (Con A-Sup) can fully reconstitute the response. Therefore, Lyt-1,2-bearing T cells are required for the generation of ABA-specific CTL, and such requirement can be replaced by factors present in the Con A- sup. Suppressor T cells (Ts), when adoptively transferred into naive recipients, will inhibit the in vivo priming of CTL. This inhibition can also be reversed by in vitro addition of Con A-Sup. furthermore, mice serving as donors of Ts also show profound unresponsiveness when primed and restimulated in vitro. In contrast to the Ts-mediated inhibition, in vitro addition of Con A-Sup was unable to abolish the unresponsiveness observed in these cultures. Thus, we identified two unresponsive states in a hapten-specific killing system that differ in their ability to be reconstituted by Con A-Sup.

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