Binding of chemical derivatives of Phaseolus vulgaris phytohemagglutinin to pig spleen lymphocytes

1980 ◽  
Vol 58 (5) ◽  
pp. 399-404 ◽  
Author(s):  
Gilles Dupuis ◽  
Sylvie Clairoux-Moreau
Keyword(s):  
Phaseolus Vulgaris ◽  
Binding Sites ◽  
Lectin Binding ◽  
Lymphocyte Activation ◽  
Binding Studies ◽  
Chemical Derivatives ◽  
Nitro Derivatives ◽  
Spleen Lymphocytes ◽  
Derivatives Of ◽  
Apparent Association

The mitogenic activity of Phaseolus vulgaris phytohemagglutinin (PHA) and its acetyl, citraconyl, glycinyl, homoarginyl, N-bromosuccinimide, and nitro derivatives has been assayed using pig spleen lymphocytes. Nitrated and N-bromosuccinimide-treated PHA were not mitogenic. Whereas the mitogenicity of acetyl PHA was impaired, the other derivatives were as active as untreated lectin. Binding studies of [125I]PHA and derivatives to purified pig spleen lymphocytes were performed at 37 °C. Results show that the lymphocytes bound various amounts of lectin derivatives. Maximum amounts were observed in the case of mitogenic lectins. Data were analyzed by Scatchard plots and two kinds of binding sites were found for PHA and the mitogenic derivatives. High affinity and low affinity binding sites have been characterized in terms of (apparent) association constant and (apparent) number of sites. Binding of PHA or its chemical derivatives to a small fraction (4.6–9.0%) of all available lectin binding sites was sufficient for maximal lymphocyte stimulation. Nonmitogenic PHA derivatives (nitro or N-bromosuccinimide) bound, with low affinity, to one kind of binding site. The relevancy of these findings to lymphocyte activation is discussed.

Lectin Binding Studies on RNA Tumor Virus-Infected Cells

1975 ◽  
Vol 33 ◽  
pp. 326-327
Author(s):  
D. C. Hixson
Keyword(s):  
Binding Sites ◽  
Lectin Binding ◽  
Culture Conditions ◽  
3T3 Cells ◽  
Binding Studies ◽  
Con A ◽  
Microscopic Studies ◽  
Tumor Virus ◽  
Infected Cells ◽  
Cell Culture Conditions

The abilities of plant lectins to preferentially agglutinate malignant cells and to bind to specific monosaccharide or oligosaccharide sequences of glycoproteins and glycolipids make them a new and important biochemical probe for investigating alterations in plasma membrane structure which may result from malignant transformation. Electron and light microscopic studies have demonstrated clustered binding sites on surfaces of SV40-infected or tryp- sinized 3T3 cells when labeled with concanavalin A (con A). No clustering of con A binding sites was observed in normal 3T3 cells. It has been proposed that topological rearrangement of lectin binding sites into clusters enables con A to agglutinate SV40-infected or trypsinized 3T3 cells (1). However, observations by other investigators have not been consistent with this proposal (2) perhaps due to differences in reagents used, cell culture conditions, or labeling techniques. The present work was undertaken to study the lectin binding properties of normal and RNA tumor virus-infected cells and their associated viruses using lectins and ferritin-conjugated lectins of five different specificities.

Effects of bovine serum albumin on the interaction of concanavalin A and succinyl-concanavalin A with phospholipid bilayers

1985 ◽  
Vol 63 (1) ◽  
pp. 64-70 ◽  
Author(s):  
Christina A. Chicken ◽  
Frances J. Sharom
Keyword(s):  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Concanavalin A ◽  
High Purity ◽  
Binding Sites ◽  
Bovine Serum ◽  
Lectin Binding ◽  
Affinity Column ◽  
Binding Studies ◽  
High Affinity

Under physiological conditions, concanavalin A interacts with the surface of phospholipid liposomes through two distinct classes of binding sites, a relatively small number of high affinity sites and a much larger number of lower affinity sites. Addition of bovine serum albumin induces extensive additional binding of concanavalin A to liposomal membranes and this binding is saturable and "specific" (α-methyl mannoside inhibitable). Fraction V and high purity albumin both induce almost identical levels of concanavalin A binding to liposomes. Scatchard plots of the binding data demonstrate the induction of a large number of new, relatively high affinity lectin-binding sites on addition of albumin. Albumin-induced binding of concanavalin A to the bilayer surface shows a broad pH optimum and is not inhibited by 40% (w/v) ethylene glycol, suggesting that hydrophobic forces are relatively unimportant. In contrast, divalent succinyl-concanavalin A shows very little tendency to bind to liposomes, either in the absence or presence of albumin. Passage of high purity albumin down a concanavalin A affinity column or treatment with periodate completely eliminates the additional lectin binding. It thus seems likely that albumin-induced concanavalin A binding to liposomes is related to the presence of a concanavalin-A-binding component. This phenomenon may have important implications for lectin-binding studies carried out on membranes which have been exposed to serum proteins.

QSAR Analysis of Selected Antimicrobial Structures Belonging to Nitro-derivatives of Heterocyclic Compounds

2020 ◽  
Vol 17 (2) ◽  
pp. 214-225 ◽  
Author(s):  
Piotr Kawczak ◽  
Leszek Bober ◽  
Tomasz Bączek
Keyword(s):  
Antimicrobial Activity ◽  
Heterocyclic Compounds ◽  
Molecular Descriptors ◽  
Microbiological Activity ◽  
Activity Data ◽  
Qsar Analysis ◽  
Qsar Models ◽  
Nitro Derivatives ◽  
Semi Empirical ◽  
Derivatives Of

Background: Nitro-derivatives of heterocyclic compounds were used as active agents against pathogenic microorganisms. A set of 4- and 5-nitroimidazole derivatives exhibiting antimicrobial activity was analyzed with the use of Quantitative Structure-Activity Relationships (QSAR) method. The study included compounds used both in documented treatment and those described as experimental. Objective: The purpose of this study was to demonstrate the common and differentiating characteristics of the above-mentioned chemical compounds alike physicochemically as well as pharmacologically based on the quantum chemical calculations and microbiological activity data. Methods: During the study PCA and MLR analysis were performed, as the types of proposed chemometric approach. The semi-empirical and ab initio level of in silico molecular modeling was performed for calculations of molecular descriptors. Results: QSAR models were proposed based on chosen descriptors. The relationship between the nitro-derivatives structure and microbiological activity data was able to class and describe the antimicrobial activity with the use of statistically significant molecular descriptors. Conclusion: The applied chemometric approaches revealed the influential features of the tested structures responsible for the antimicrobial activity of studied nitro-derivatives.

Electrochemical reduction of para-substituted 2-acyl-5-phenylfuranes in dimethylformamide

1981 ◽  
Vol 46 (2) ◽  
pp. 498-502 ◽  
Author(s):  
Jozef Černák ◽  
František Tomanovič ◽  
Andrej Staško ◽  
Anna Fedosyevna Oleinikova ◽  
Jaroslav Kováč
Keyword(s):  
Electrochemical Reduction ◽  
Unpaired Electron ◽  
Anion Radical ◽  
Electron Wave ◽  
Epr Method ◽  
Electron Center ◽  
Nitrogen Nucleus ◽  
Nitro Derivatives ◽  
Stable Anion ◽  
Derivatives Of

para Substituted chloro, bromo, and nitro derivatives of 2-acyl-5-phenylfurane are reduced polarographically in a one-electron wave to the corresponding anion radicals, which were studied by the EPR method. The reduction of nitro derivatives, studied by the Kalousek switch, is reversible and leads to a stable anion radical with an unpaired electron center on the nitrogen nucleus; the reduction of the halogen derivatives is only partly reversible and leads to unstable ketyl radicals. The bromo derivatives give polarographic maxima typical for concurrent reactions.

scholarly journals Chemical Derivatives of α-Chymotrypsinogen

1960 ◽  
Vol 235 (2) ◽  
pp. 396-404
Author(s):  
Djahanguir M. Abadi ◽  
Philip E. Wilcox
Keyword(s):  
Chemical Derivatives ◽  
Derivatives Of

scholarly journals Chemical Derivatives of α-Chymotrypsinogen

1961 ◽  
Vol 236 (5) ◽  
pp. 1328-1337
Author(s):  
Marilynn S. Doscher ◽  
Philip E. Wilcox
Keyword(s):  
Chemical Derivatives ◽  
Derivatives Of

Glycosylation of developing human glomeruli: lectin binding sites during cell induction and maturation.

1987 ◽  
Vol 35 (1) ◽  
pp. 33-37 ◽  
Author(s):  
H Holthöfer ◽  
I Virtanen
Keyword(s):  
Binding Sites ◽  
Mesangial Cells ◽  
Ricinus Communis ◽  
Lectin Binding ◽  
Helix Pomatia ◽  
Cell Types ◽  
Basement Membranes ◽  
Phenotypic Change ◽  
Neuraminidase Treatment ◽  
Nephron Development

Expression of cellular glycoconjugates during differentiation of human fetal kidney was studied using fluorochrome-labeled lectins. Each lectin revealed a characteristic binding pattern during the phenotypic change of the nephrogenic mesenchyme and during distinct stages of nephron development. The uninduced mesenchymal cells were positive for Pisum sativum (PSA), Concanavalin A (ConA), Wistaria floribunda (WGA), and Ricinus communis (RCA-I) lectins. However, these lectins failed to react with the uninduced cells of the S-shaped bodies, whereas Maclura pomifera (MPA), Triticum vulgaris (WGA) and, after neuraminidase treatment, Arachis hypogaea (PNA) agglutinins bound intensely to the presumptive podocytes. During later stages of nephrogenesis, MPA positively on the podocytes weakened and could not be observed in adult kidney glomeruli. Binding sites for Helix pomatia (HPA) agglutinin in glomeruli were also expressed only transiently during nephrogenesis. During further development PSA, ConA, WFA, and RCA-I reacted with mesangial cells in addition to the glomerular basement membranes. The segment-specific lectin binding patterns of the tubuli emerged in parallel with the appearance of brush border and Tamm-Horsfall antigens of the proximal and distal tubuli. The results show that nephron site-specific saccharides appear in a developmentally regulated manner and in parallel with morphologic maturation of the nephron. Lectins therefore appear to be useful tools for study of induction and maturation of various nephron cell types.

Synthesis of 5,7-dihydroxynaphthoquinone derivatives and their reactions with nucleophiles: Nitration of 2,3-dimethylnaphthalene and subsequent transformations

1976 ◽  
Vol 29 (10) ◽  
pp. 2247 ◽  
Author(s):  
HJ Banks ◽  
DW Cameron ◽  
MJ Crossley ◽  
EL Samuel
Keyword(s):  
Unusual Reaction ◽  
Nitro Derivatives ◽  
Reactions With Nucleophiles ◽  
Derivatives Of ◽  
Related Compounds ◽  
Benzenoid Ring

5,7-Dihydroxy-2,3-dimethyl-l,4-naphthoquinone (5) and related compounds have been synthesized. The quinone affords an accessible substrate for studying an unusual reaction with nucleophiles, which involves attack at the 8-position, i.e. at the benzenoid ring. An unsuccessful approach to (5) has led to tri- and tetra-nitro derivatives of 2,3-dimethylnaphthalene. Reduction of the former and subsequent conversions have given aminonaphthoquinone and perimidinone derivatives.

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