scholarly journals The glycoprotein nature of pig kidney diamine oxidase. Role of disulphide groups and arginine residues in the concanavalin A-diamine oxidase interaction

1988 ◽  
Vol 253 (1) ◽  
pp. 103-107 ◽  
Author(s):  
M A Shah ◽  
R Ali
Keyword(s):  
Concanavalin A ◽  
Diamine Oxidase ◽  
Con A ◽  
Acetylneuraminic Acid ◽  
Pig Kidney ◽  
Arginine Residues ◽  
Arginine Modification ◽  
Kinetics Of ◽  
Protein Moiety

Pig kidney diamine oxidase (DAO) was found to contain 5% (w/w) natural hexose, 3.25% glucosamine, 2.61% N-acetylglucosamine and 0.25% N-acetylneuraminic acid. The enzyme exhibited strong affinity towards concanavalin A (Con A) with a stoichiometry of 1:4.6. The kinetics of interaction approached an apparent first-order rate, with a rate constant (Kapp.) value of 1.5 × 10(-2) min-1. The enzyme reduced with dithiothreitol followed by alkylation with iodoacetamide showed an increase in the stoichiometry of the Con A-DAO interaction. Similarly arginine modification by phenylglyoxal caused decreased affinity, with an altered Kapp. value of 9.09 × 10(-3) min-1. The results suggest that, besides the carbohydrate content, the protein moiety of the enzyme also plays a significant role in the Con A-DAO interaction.

scholarly journals Concanavalin-A Induces Granulosa Cell Death and Inhibits FSH-Mediated Follicular Growth and Ovarian Maturation in Female Rats

Endocrinology ◽  
2013 ◽  
Vol 154 (5) ◽  
pp. 1885-1896 ◽  
Author(s):  
Ethel V. Velasquez ◽  
Mariana Ríos ◽  
María Elena Ortiz ◽  
Carlos Lizama ◽  
Elizabeth Nuñez ◽  
...  
Keyword(s):  
Cell Death ◽  
Granulosa Cell ◽  
Granulosa Cells ◽  
Concanavalin A ◽  
Ex Vivo ◽  
Female Rats ◽  
Carbohydrate Binding ◽  
Con A ◽  
Follicular Maturation

Abstract Reproductive success stems from a finely regulated balance between follicular maturation and atresia, in which the role of carbohydrate structure is poorly understood. Here, we describe for the first time a fraction of purified recombinant human FSH that is capable of bringing about the cell death of granulosa cells and preventing follicular maturation in a rat model. Further analysis by mass spectrometry revealed the presence of the lectin Concanavalin-A (Con-A) within this fraction of recombinant FSH. Using both the fractionated FSH and Con-A, the observed cell death was predominantly located to the granulosa cells. Ex vivo culture of rat follicles demonstrated that follicle degeneration occurred and resulted in the release of a denuded and deteriorated oocyte. Moreover, in vivo experiments confirmed an increase in atresia and a corresponding reduction confined to follicle in early antral stage. As a mechanism of action, Con-A reduces ovarian proliferation, Von Willebrand staining, and angiogenesis. Based on the observation that Con-A may induce granulosa cell death followed by follicle death, our results further demonstrate that follicular carbohydrate moiety is changing under the influence of FSH, which may allow a carbohydrate-binding lectin to increase granulosa cell death. The physiological consequences of circulating lectin-like molecules remain to be determined. However, our results suggest a potential exploitation of carbohydrate binding in fertility and ovarian cancer treatment. This work may shed light on a key role of carbohydrates in the still obscure physiological process of follicular selection and atresia.

scholarly journals Alkaline phosphatase from pig kidney. Microheterogeneity and the role of neuraminic acid

1974 ◽  
Vol 141 (1) ◽  
pp. 293-298 ◽  
Author(s):  
Kunio Hiwada ◽  
Ernst D. Wachsmuth
Keyword(s):  
Alkaline Phosphatase ◽  
Brush Border Membrane ◽  
Deae Cellulose ◽  
Multiple Forms ◽  
Alkaline Phosphatases ◽  
Acetylneuraminic Acid ◽  
Pig Kidney ◽  
Ph Dependency ◽  
Polypeptide Chains

Several alkaline phosphatases (EC 3.1.3.1) could be obtained from pig kidney brush-border membrane on extraction with butan-1-ol. Three of the multiple forms were separated by DEAE-cellulose chromatography and further purified. They form a regular series with different degrees of glycosylation (mainly owing to N-acetylneuraminic acid), of charge, of molecular weight, of stability to temperature, to pH and to urea, of minimal requirement for Mg2+ and of extractability by butan-1-ol. In contrast, the detectable antigenic sites, the inhibition by amino acids and the pH-dependency of Km and Vmax. were identical for these multiple forms. On treatment with neuraminidase, the multiple forms became identical in all their properties. It was therefore concluded that the microheterogeneity of alkaline phosphatase is due to different degrees of glycosylation at polypeptide chains which appear to be otherwise identical.

scholarly journals Glycophorin A interferes in the agglutination of human erythrocytes by concanavalin A Explanation of the requirement for enzymic predigestion

1987 ◽  
Vol 241 (2) ◽  
pp. 505-511 ◽  
Author(s):  
S M Gokhale ◽  
N G Mehta
Keyword(s):  
Sialic Acid ◽  
Correlation Coefficient ◽  
Concanavalin A ◽  
Binding Sites ◽  
Band 3 ◽  
Human Erythrocytes ◽  
The Other ◽  
Glycophorin A ◽  
Con A

Human erythrocytes become agglutinable with concanavalin A (Con A) after treatment with various proteinases or neuraminidase. The extent of agglutinability achieved with different enzymes is, however, different: Pronase, papain, trypsin, neuraminidase and chymotrypsin enhance the agglutinability in decreasing order, the last being barely effective. The actions of the enzymes on band 3, the Con A receptor, do not correlate with their abilities to increase the agglutinability: Pronase, papain and chymotrypsin cleave the protein, but not trypsin or neuraminidase. No significant differences are found in the number of Con A-binding sites or the affinities for the lectin between the normal and trypsin- or Pronase-treated cells. Thus the receptor does not seem to play a role in determining the Con A-agglutinability of erythrocytes. On the other hand, the cleavage of glycophorins, especially glycophorin A, and the release of sialic acid (in the peptide-bound form) are well-correlated with the enhancement in agglutination after the action of proteinases. The release of sialic acid by graded neuraminidase digestion and the increase in Con A-agglutinability show a correlation coefficient of 0.88. The major inhibitory role of glycophorin A in the process is indicated by the agglutination of En(a) heterozygous erythrocytes; the cells, known to bear about 50% glycophorin A molecules in their membrane, are agglutinated approximately half as well without proteolysis as are the trypsin-treated cells. Possible mechanisms by which glycophorin A could affect Con A-mediated agglutination are discussed.

The role of the cell surface in the migration of primordial germ cells in early chick embryos: effects of concanavalin A

Development ◽  
1978 ◽  
Vol 46 (1) ◽  
pp. 5-20
Author(s):  
H. Lee ◽  
N. Karasanyi ◽  
R. G. Nagele
Keyword(s):  
Cell Surface ◽  
Germ Cells ◽  
Concanavalin A ◽  
Primordial Germ Cells ◽  
Sublethal Dose ◽  
Chick Embryos ◽  
Con A ◽  
And Migration ◽  
Coat Material

Effects of concanavalin A (Con A) on the morphology and migration of primordial germ cells (PGCs) in stage-6 to -12 chick embryos were investigated. Con A, at a sublethal dose (10µg/ml), inhibited migration of PGCs from the germinal crescent area to other parts of the embryo. Affected PGCs were more rounded without the usual cytoplasmic extensions, but the integrity of other structures was unaffected. Nearly identical results were obtained with another lectin, wheat germ agglutinin (10µg/ml). Histochemistry using Con A-horseradish peroxidase revealed that PGCs in control embryos had a thin, rather uniform layer of extracellular coat material (ECM). Con A appeared to alter the distribution of ECM on PGCs, i.e. some parts of the cell surface were devoid of any detectable ECM, while others had small, scattered patches of ECM. Con A effects were alleviated by α-methyl-d-mannoside. Overall results of the present study indicated that the observed inhibition of PGC migration in early chick embryos is a consequence of Con A-induced alterations of cell surface properties.

scholarly journals Antioxidant Capacity and Hepatoprotective Role of Chitosan-Stabilized Selenium Nanoparticles in Concanavalin A-Induced Liver Injury in Mice

Nutrients ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 857 ◽  
Author(s):  
Kaikai Bai ◽  
Bihong Hong ◽  
Jianlin He ◽  
Wenwen Huang
Keyword(s):  
Liver Injury ◽  
Antioxidant Capacity ◽  
Concanavalin A ◽  
Radical Scavenging ◽  
Lactic Dehydrogenase ◽  
Selenium Nanoparticles ◽  
Con A ◽  
Ultra Filtration ◽  
Hepatocyte Necrosis

Selenium nanoparticles (SeNPs) have attracted wide attention for their use in nutritional supplements and nanomedicine applications. However, their potential to protect against autoimmune hepatitis has not been fully investigated, and the role of their antioxidant capacity in hepatoprotection is uncertain. In this study, chitosan-stabilized SeNPs (CS-SeNPs) were prepared by means of rapid ultra-filtration, and then their antioxidant ability and free-radical scavenging capacity were evaluated. The hepatoprotective potential of a spray-dried CS-SeNPs powder against autoimmune liver disease was also studied in the concanavalin A (Con A)-induced liver injury mouse model. CS-SeNPs with size of around 60 nm exhibited acceptable oxygen radical absorbance capacity and were able to scavenge DPPH, superoxide anion, and hydroxyl radicals. The CS-SeNPs powder alleviated Con A-caused hepatocyte necrosis and reduced the elevated levels of serum alanine transaminase, aspartate transaminase, and lactic dehydrogenase in Con A-treated mice. These results suggest that the CS-SeNPs powder protected the mice from Con-A-induced oxidative stress in the liver by retarding lipid oxidation and by boosting the activities of superoxide dismutase, glutathione peroxidase, and catalase, partly because of its ability to improve Se retention. In conclusion, SeNPs present potent hepatoprotective potential against Con A-induced liver damage by enhancing the redox state in the liver; therefore, they deserve further development.

scholarly journals The Role of Serotonin in Concanavalin A-Induced Liver Injury in Mice

2020 ◽  
Vol 2020 ◽  
pp. 1-16 ◽  
Author(s):  
Qing Pang ◽  
Hao Jin ◽  
Xiquan Ke ◽  
Zhongran Man ◽  
Yong Wang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Liver Injury ◽  
Inflammatory Response ◽  
Concanavalin A ◽  
Serum Levels ◽  
Hepatocyte Apoptosis ◽  
Con A ◽  
Serotonin 2A Receptor ◽  
Serotonin 2A

Serotonin is involved in the pathological processes of several liver diseases via the regulation of inflammatory response and oxidative stress. We aimed to investigate the role of serotonin in Concanavalin A- (Con A-) induced acute liver injury (ALI). ALI was induced in C57B/6 wild-type (WT) mice and tryptophan hydroxylase 1 (TPH1) knockout mice through tail vein injection of Con A (15 mg/kg body weight). Another group of TPH1 knockout ALI mice was supplied with 5-hydroxytryptophan (5-HTP) in advance to recover serotonin. The blood and liver tissues of mice were collected in all groups. Markedly increased serum levels of serotonin were identified after the injection of Con A. Increased serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and stronger hepatic tissue pathology were detected, suggesting that serotonin could mediate Con A-induced liver damage. Serotonin significantly facilitated the release of serum and intrahepatic inflammatory cytokines, including interleukin-2 (IL-2), interleukin-6 (IL-6), interleukin-17A (IL-17A), interferon-gamma (IFN-γ), and tumor necrosis-alpha (TNF-α), after the administration of Con A. In addition, serotonin significantly increased the intrahepatic levels of oxidative stress markers malonaldehyde (MDA), myeloperoxidase (MPO), and nitric oxide (NO) and decreased antioxidant stress indicator glutathione (GSH) in Con A-treated mice. Additionally, serotonin promoted hepatocyte apoptosis and autophagy based on B-cell lymphoma-2 (Bcl-2), Bcl-2-asociated X protein (Bax), and Beclin-1 levels and TUNEL staining. More importantly, serotonin activated nuclear factor kappa B (NF-κB) and upregulated the hepatic expressions of high mobility group protein B1 (HMGB1), toll-like receptor-4 (TLR4), and downstream molecules in Con A-mediated liver injury. Serotonin 2A receptor was upregulated in liver tissue after Con A injection, and serotonin 2A receptor antagonist Ketanserin protected against Con A-induced hepatitis. These results indicated that serotonin has the potential to aggravate Con A-induced ALI via the promotion of inflammatory response, oxidative stress injury, and hepatocyte apoptosis and the activation of hepatic HMGB1-TLR signaling pathway and serotonin 2A receptor.

scholarly journals Concanavalin A-agglutinability of membrane-skeleton-free vesicles and aged cellular remnants derived from human erythrocytes. Is the membrane skeleton required for agglutination?

1987 ◽  
Vol 241 (2) ◽  
pp. 513-520 ◽  
Author(s):  
S M Gokhale ◽  
N G Mehta
Keyword(s):  
Concanavalin A ◽  
Wheat Germ Agglutinin ◽  
Wheat Germ ◽  
Ricinus Communis ◽  
Membrane Skeleton ◽  
Con A ◽  
Intact Cells ◽  
Rigid Skeleton

Vesicles and cell remnants have been obtained by aging of erythrocytes in vitro. The vesicles lacking the membrane skeletal proteins and the remnants known to possess a rigid skeleton have been used to assess the role of membrane skeletal proteins in the process of Con A (concanavalin A)-mediated agglutination of erythrocytes. Both the vesicles and the remnants were found to bind Con A at the same density as did intact cells. The vesicles, isolated from normal as well as from the Con A-agglutinable trypsin- and Pronase-treated cells, failed to agglutinate with Con A. They were, however, well agglutinated by WGA (wheat-germ agglutinin) and RCA [Ricinus communis (castor bean) agglutinin], indicating that the vesicles are not defective in agglutination. Large, cytoskeleton-free, vesicles prepared by another procedure also gave the same results. The aged remnants from trypsin- and Pronase-treated erythrocytes showed significantly decreased agglutination with Con A, but were agglutinated as well as the fresh cells by WGA and RCA. The agglutination with Con A is thus abolished when the membrane skeleton is absent, and reduced when it is rigid, suggesting that the skeleton may play an important role in the agglutination of erythrocytes by Con A.

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.

scholarly journals A role for P-selectin in neutrophil and platelet infiltration in immune complex glomerulonephritis.

1997 ◽  
Vol 8 (12) ◽  
pp. 1838-1844 ◽  
Author(s):  
C R Zachem ◽  
C E Alpers ◽  
W Way ◽  
S J Shankland ◽  
W G Couser ◽  
...  
Keyword(s):  
Immune Complex ◽  
Concanavalin A ◽  
Leukocyte Adhesion ◽  
Glomerular Injury ◽  
Con A ◽  
Inflammatory Conditions ◽  
Platelet Accumulation ◽  
Macrophage Accumulation ◽  
Neutrophil Infiltrate

P-selectin is one of the key early mediators of leukocyte adhesion in inflammatory conditions. This report examines the role of P-selectin in a neutrophil- and platelet-mediated model of glomerulonephritis (the concanavalin A [con A] model). The administration of neutralizing anti-P-selectin antibody (PB 1.3) reduced the platelet influx at 10 min (P < 0.05) and was associated with a 60% reduction in the neutrophil infiltrate and a 50% reduction in the number of oxidant-producing cells at 3 h within glomeruli. No effect on glomerular monocyte-macrophage accumulation was observed, and proteinuria was reduced by 20% but did not reach significance. It is concluded that P-selectin plays an important role in mediating the neutrophil and platelet accumulation in this model and likely has a role in mediating the glomerular injury.

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