Role of receptor aggregation in complement-dependent inhibition of lymphocytes by high concentrations of concanavalin A

Nature ◽  
1977 ◽  
Vol 267 (5609) ◽  
pp. 358-360 ◽  
Author(s):  
D. R. FORSDYKE
Keyword(s):  
Concanavalin A ◽  
Receptor Aggregation ◽  
Dependent Inhibition ◽  
High Concentrations

Evidence for a relationship between chloroquine and complement from studies with lymphocyte mitogens: possible implications for the mechanism of action of chloroquine in disease

1975 ◽  
Vol 21 (10) ◽  
pp. 1581-1586 ◽  
Author(s):  
D. R. Forsdyke
Keyword(s):  
Autoimmune Disease ◽  
Mechanism Of Action ◽  
Concanavalin A ◽  
Time Course ◽  
Con A ◽  
Therapeutic Value ◽  
Dependent Inhibition ◽  
High Concentrations

Chloroquine increases the inhibition of cultured lymphocytes by high concentrations of phytohemagglutinin (PHA) or concanavalin A (Con A). The inhibition is also increased by complement. Thus chloroquine and complement have similar effects. Time-course studies show that chloroquine increases the rate of onset of the complement-dependent inhibition. In serum preheated to inactivate complement, chloroquine can partially simulate the effect of complement. It is suggested that at certain stages in malaria or autoimmune disease the rate of clearance of parasitized erythrocytes or autoreactive lymphocytes is limited by the concentration of complement. Under these conditions a drug such as chloroquine, which could enhance or simulate the action of complement, might be of therapeutic value.

Protein–carbohydrate interaction. XV. The role of bivalent cations in concanavalin A – polysaccharide interaction

1968 ◽  
Vol 46 (9) ◽  
pp. 1147-1150 ◽  
Author(s):  
B. B. L. Agrawal ◽  
I. J. Goldstein
Keyword(s):  
Acetic Acid ◽  
Protein Structure ◽  
Concanavalin A ◽  
Optimum Range ◽  
Metal Free ◽  
Cation Concentration ◽  
Bivalent Cations ◽  
High Concentrations

Extensive dialysis of concanavalin A solution against 1.0 M acetic acid results in the loss of its ability to precipitate specific polysaccharides. This activity is restored upon the addition of bivalent cations such as Mg2+, Mn2+, Ca2+, Co2+, and Zn2+. An optimum range of the cation concentration is observed for the activation of metal-free concanavalin A. High concentrations of bivalent cations (> 0.05 M) are inhibitory to the interaction of concanavalin A with specific polysaccharides. Of all the metals tested, Mn2+ appears to be bound most strongly. Urea and guanidine-HCl cause the inhibition of polysaccharide-precipitating activity of concanavalin A, probably by virtue of their unfolding effect on the protein structure.

The role of microbiota in concanavalin A-mediated liver injury

2018 ◽  
Vol 56 (01) ◽  
pp. E2-E89
Author(s):  
B Schiller ◽  
C Wegscheid ◽  
L Berkhout ◽  
A Zarzycka ◽  
U Steinhoff ◽  
...  
Keyword(s):  
Liver Injury ◽  
Concanavalin A

Investigation on the antibacterial activity of electronic cigarette liquids (ECLs): a proof of concept study

2020 ◽  
Vol 21 ◽  
Author(s):  
Virginia Fuochi ◽  
Massimo Caruso ◽  
Rosalia Emma ◽  
Aldo Stivala ◽  
Riccardo Polosa ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Bacterial Species ◽  
A549 Cells ◽  
Bactericidal Effect ◽  
Minimal Bactericidal Concentration ◽  
Viability Assay ◽  
Dependent Inhibition ◽  
Dose Dependent Inhibition ◽  
Dose Dependent

Background: The key ingredients of e-cigarettes liquid are commonly propane-1,2-diol (also called propylene glycol) and propane-1,2,3-triol (vegetal glycerol) and their antimicrobial effects are already established. The nicotine and flavors which are often present in e-liquids can interfere with the growth of some microorganisms. Objective: The effect of the combining these elements in e-liquids is unknown. The aim of the study was to investigate the possible effects of these liquids on bacterial growth in the presence or absence of nicotine and flavors. Methods: Susceptibilities of pathogenic strains (Klebsiella pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumannii, Escherichia coli, Enterococcus faecalis and Sarcina lutea) were studied by means of a multidisciplinary approach. Cell viability and antioxidant assays were also evaluated. Results: All e-liquids investigated showed antibacterial activity against at least one pathogenic strain. A higher activity was correlated to the presence of flavors and nicotine. Discussion: In most cases the value of minimal bactericidal concentration is equal to the value of minimal inhibitory concentration showing that these substances have a bactericidal effect. This effect was observed in concentrations up to 6.25% v/v. Antioxidant activity was also correlated to presence of flavors. Over time, the viability assay in human epithelial lung A549 cells showed a dose-dependent inhibition of cell growth. Conclusion: Our results have shown that flavors considerably enhance the antibacterial activity of propane-1,2-diol and propane-1,2,3-triol. This study provides important evidence that should be taken into consideration in further investigative approaches, to clarify the different sensitivity of the various bacterial species to e-liquids, including the respiratory microbiota, to highlight the possible role of flavors and nicotine.

scholarly journals TP53-Induced Glycolysis and Apoptosis Regulator (TIGAR) Is Upregulated in Lymphocytes Stimulated with Concanavalin A

2021 ◽  
Vol 22 (14) ◽  
pp. 7436
Author(s):  
Helga Simon-Molas ◽  
Xavier Vallvé-Martínez ◽  
Irene Caldera-Quevedo ◽  
Pere Fontova ◽  
Claudia Arnedo-Pac ◽  
...  
Keyword(s):  
Concanavalin A ◽  
Carbon Flux ◽  
Human Lymphocytes ◽  
Tumor Development ◽  
Pentose Phosphate ◽  
Akt Signaling Pathway ◽  
G6pdh Activity ◽  
Physiological Conditions ◽  
Glucose 6 Phosphate Dehydrogenase

The glycolytic modulator TP53-Inducible Glycolysis and Apoptosis Regulator (TIGAR) is overexpressed in several types of cancer and has a role in metabolic rewiring during tumor development. However, little is known about the role of this enzyme in proliferative tissues under physiological conditions. In the current work, we analysed the role of TIGAR in primary human lymphocytes stimulated with the mitotic agent Concanavalin A (ConA). We found that TIGAR expression was induced in stimulated lymphocytes through the PI3K/AKT pathway, since Akti-1/2 and LY294002 inhibitors prevented the upregulation of TIGAR in response to ConA. In addition, suppression of TIGAR expression by siRNA decreased the levels of the proliferative marker PCNA and increased cellular ROS levels. In this model, TIGAR was found to support the activity of glucose 6-phosphate dehydrogenase (G6PDH), the first enzyme of the pentose phosphate pathway (PPP), since the inhibition of TIGAR reduced G6PDH activity and increased autophagy. In conclusion, we demonstrate here that TIGAR is upregulated in stimulated human lymphocytes through the PI3K/AKT signaling pathway, which contributes to the redirection of the carbon flux to the PPP.

scholarly journals Environmentally persistent free radicals are ubiquitous in wildfire charcoals and remain stable for years

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Gabriel Sigmund ◽  
Cristina Santín ◽  
Marc Pignitter ◽  
Nathalie Tepe ◽  
Stefan H. Doerr ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Free Radicals ◽  
Reactive Oxygen ◽  
Resonance Spectroscopy ◽  
Oxygen Species ◽  
Pyrogenic Carbon ◽  
Spin Resonance ◽  
Long Time ◽  
High Concentrations

AbstractGlobally landscape fires produce about 256 Tg of pyrogenic carbon or charcoal each year. The role of charcoal as a source of environmentally persistent free radicals, which are precursors of potentially harmful reactive oxygen species, is poorly constrained. Here, we analyse 60 charcoal samples collected from 10 wildfires, that include crown as well as surface fires in forest, shrubland and grassland spanning different boreal, temperate, subtropical and tropical climate. Using electron spin resonance spectroscopy, we measure high concentrations of environmentally persistent free radicals in charcoal samples, much higher than those found in soils. Concentrations increased with degree of carbonization and woody fuels favoured higher concentrations. Moreover, environmentally persistent free radicals remained stable for an unexpectedly long time of at least 5 years. We suggest that wildfire charcoal is an important global source of environmentally persistent free radicals, and therefore potentially of harmful reactive oxygen species.

scholarly journals Atypical role of sprouty in p21 dependent inhibition of cell proliferation in colorectal cancer

2015 ◽  
Vol 55 (9) ◽  
pp. 1355-1368 ◽  
Author(s):  
Qiong Zhang ◽  
Katherine Shim ◽  
Kevin Wright ◽  
Alexander Jurkevich ◽  
Sharad Khare
Keyword(s):  
Colorectal Cancer ◽  
Cell Proliferation ◽  
Dependent Inhibition

scholarly journals The Role of CYP2C8 and CYP2C9 Genotypes in Losartan-Dependent Inhibition of Paclitaxel Metabolism in Human Liver Microsomes

2015 ◽  
Vol 118 (6) ◽  
pp. 408-414 ◽  
Author(s):  
Yuji Mukai ◽  
Asuna Senda ◽  
Takaki Toda ◽  
Erik Eliasson ◽  
Anders Rane ◽  
...  
Keyword(s):  
Human Liver ◽  
Liver Microsomes ◽  
Human Liver Microsomes ◽  
Dependent Inhibition

Singlet oxygen feedback delayed fluorescence of protoporphyrin IX in organic solutions

2017 ◽  
Vol 16 (4) ◽  
pp. 507-518 ◽  
Author(s):  
Ivo S. Vinklárek ◽  
Marek Scholz ◽  
Roman Dědic ◽  
Jan Hála
Keyword(s):  
Partial Pressure ◽  
Singlet Oxygen ◽  
Protoporphyrin Ix ◽  
Clinical Applications ◽  
Delayed Fluorescence ◽  
Diagnostic Tools ◽  
Partial Pressure Of Oxygen ◽  
High Concentrations ◽  
Organic Solutions

The PpIX DF show the significant role of SOFDF mechanism at high concentrations and at atmospheric partial pressure of oxygen and should be considered when developing diagnostic tools for clinical applications.

Sign in / Sign up

Export Citation Format

Share Document