Search results for "Formazan"
showing 10 items of 15 documents
Synthesis, characterization, and cytotoxic activity of copper(II) and platinum(II) complexes of 2-benzoylpyrrole and X-ray structure of bis[2-benzoyl…
2004
Copper(II) and platinum(II) complexes of 2-benzoylpyrrole (2-BZPH) were synthesized and characterized with IR, 1 H and 1 3 C NMR spectroscopies and coordination geometry with ligands arranged in transoid fashion. The crystal structure of [Cu I I (2-BZP) 2 ] was determined by X-ray diffraction. Death of complex treated Jurkat cells was measured by flow cytometry. The bis-chelate complexes [Cu I I (2-BZP) 2 ] and [Pt I I (2-BZP) 2 ] adopt square-planar coordination geometry with ligands, arranged in transoid fashion. Concentrations of 1-10 μM Platinum(II) complexes reduced cell survival from 100% to 20%, in contrast to the copper(II) complex which caused no cell death at a concentration of 10…
Development of a rapid and highly sensitive biochemical method for the measurement of fungal spore viability. An alternative to the CFU method
2001
Abstract 1 A biochemical method, based on dehydrogenase activity (DHA) measurement, has been developed as an alternative to colony forming unit (CFU) enumeration, for assessing the viability of fungal spores. In viable cells, a tetrazolium salt (MTT) is reduced to a coloured formazan (MTTf) by cellular dehydrogenase enzymes. From the colorimetric assay developed by Mosmann for mammalian cells, the procedure has been adapted and optimised using P. digitatum spores as a model. Propan-2-ol has been selected as the best solvent to extract the MTTf from the spores. The sensitivity of the method has been considerably increased by determining the optimal conditions of incubation for the MTT reduct…
Experimental conditions affect the site of tetrazolium violet reduction in the electron transport chain of Lactococcus lactis
2009
The reduction of tetrazolium salts to coloured formazans is often used as an indicator of cell metabolism during microbiology studies, although the reduction mechanisms have never clearly been established in bacteria. The objective of the present study was to identify the reduction mechanisms of tetrazolium violet (TV) in Lactococcus lactis using a mutagenesis approach, under two experimental conditions generally applied in microbiology: a plate test with growing cells, and a liquid test with non-growing (resting) cells. The results showed that in both tests, TV reduction resulted from electron transfer from an intracellular donor (mainly NADH) to TV via the electron transport chain (ETC), …
Cytotoxic effects of mycotoxin combinations in mammalian kidney cells
2011
The cytotoxicity of three Fusarium mycotoxins (beauvericin, deoxynivalenol and T-2 toxin) has been investigated using the NR assay, after 24, 48 and 72h of incubation. The IC(50) values ranged from 6.77 to 11.08, 3.30 to 10.00 and 0.004 to 0.005 for beauvericin, deoxynivalenol and T-2 toxin, respectively. Once the potential interaction has been detected, a quantitative assessment is necessary to ensure and characterize these interactions, that is, each mycotoxin contributes to the toxic effect in accord with its own potency. Combination of mycotoxins was determined in Vero cells after 24, 48 and 72h of exposure. Isobolograms and median effect method of Chou and Talalay were used to assess t…
The use of cultured hepatocytes to investigate the metabolism of drugs and mechanisms of drug hepatotoxicity.
2001
Hepatotoxins can be classified as intrinsic when they exert their effects on all individuals in a dose-dependent manner, and as idiosyncratic when their effects are the consequence of an abnormal metabolism of the drug by susceptible individuals (metabolic idiosyncrasy) or of an immune-mediated injury to hepatocytes (allergic hepatitis). Some xenobiotics are electrophilic, and others are biotransformed by the liver into highly reactive metabolites that are usually more toxic than the parent compound. This activation process is the key to many hepatotoxic phenomena. Mitochondria are a frequent target of hepatotoxic drugs, and the alteration of their function has immediate effects on the ene…
Upon oxidative stress, the antiapoptotic Hsp60/procaspase-3 complex persists in mucoepidermoid carcinoma cells.
2008
Hsp60, a mitochondrial chaperonin highly conserved during evolution, has been found elevated in the cytosol of cancer cells, both in vivo and in vitro, but its role in determining apoptosis during oxidative stress (OS) has not yet been fully elucidated. The aim of the present work was to study the effects of OS on Hsp60 levels and its interactions with procaspase- 3 (p-C3) and p53 in tumor cells. NCI-H292 (mucoepidermoid carcinoma) cells were exposed to various concentrations of hydrogen peroxide (H2O2) for 24 hours. Cell viability was determined by Trypan blue and MTT assays. DNA damage was assessed by the Comet assay, and apoptosis was measured by the AnnexinV cytofluorimetric test. Expos…
Screening of lactic acid bacteria for reducing power using a tetrazolium salt reduction method on milk agar.
2013
WOS:000315703100020 ; www.elsevier.com/locate/jbiosc; International audience; Reducing activity is a physiological property of lactic acid bacteria (LAB) of technological importance. We developed a solid medium with tetrazolium dyes enabling weakly and strongly reducing LAB to be discriminated. It was used to quantify populations in a mixed culture (spreading method) and screen strains (spot method).
Potential hepatoprotective effects of new Cuban natural products in rat hepatocytes culture.
2008
The protective effects of five Cuban natural products (Mangifera indica L. (MSBE), Erythroxylum minutifolium, Erythroxylum confusum, Thalassia testudinum and Dictyota pinnatifida extracts and mangiferin) on the oxidative damage induced by model toxicants in rat hepatocyte cultures were studied. Cells were pre-incubated with the natural products (5-200 microg/mL) for 24 h. Then hepatotoxins (tert-butyl hydroperoxide, ethanol, carbon tetrachloride and lipopolysaccharide) were individually added and post-incubated for another 24 h. After treatments, cell viability was determined using the MTT assay. Mangiferin and MSBE exhibited the highest cytoprotective potential (EC50 between 50 and 125 mic…
Toxicity of used orthodontic archwires assessed by three-dimensional cell culture
2006
The aim of the present study was to determine whether used orthodontic wires made of different materials cause toxicity and loss of viability on three-dimensional (3D) cell cultures. Three types of orthodontic wires, stainless steel, Nitinol, and TMA (n = 9) which had been used clinically in fixed appliances for a period of 1 month, were retrieved at random from five patients. Both upper and lower archwires were collected and subjected to two different protocols: to assess toxicity, two pieces of each wire were placed on 3D cell cultures (reconstituted human epithelium); to investigate the possibility of cell damage, the 3-(4,5-dimethylthiazol-2-yl)2,5-diphenyl tetrazolium bromide (MTT) ass…
Nitroblue-tetrazolium test for the functional evaluation of phagocytic cells: a critical analysis of the methodology.
1981
The reduction of NBT to formazan has been suggested as an indicator of the reduction potential of biological systems. An increase in the amount of reduced formazan reflects the activation of the hexose monophosphate shunt of phagocytes cultivated in vitro, as a result of cellular stimulation by chemical or biological factors, or during phagocytosis. This phenomenon has been widely used for the determination of activated phagocytes by different methods. However, the technical limitations of these methods have not been evaluated carefully. In the investigations presented here three solvents for formazan, pyridine, dioxane and dimethyl-formamide, have been tested for their suitability as extra…