Search results for "Oxidation."
showing 10 items of 1877 documents
Squaramide-based reagent for selective chromogenic sensing of Cu(II) through a zwitterion radical.
2010
A minimalist squaramide-based chemodosimeter for Cu(2+) is described. Upon selective chelation to 2, Cu(2+) induces the formation of a highly colored zwitterionic radical, which is kinetically stable for hours. The presence of a radical is confirmed by EPR and ESI-MS. It is then possible to use reagent 2 for visual and selective sensing of Cu(2+) at neutral pH.
Increased p53 mutation load in nontumorous human liver of Wilson disease and hemochromatosis: Oxyradical overload diseases
2000
Hemochromatosis and Wilson disease (WD), characterized by the excess hepatic deposition of iron and copper, respectively, produce oxidative stress and increase the risk of liver cancer. Because the frequency of p53 mutated alleles in nontumorous human tissue may be a biomarker of oxyradical damage and identify individuals at increased cancer risk, we have determined the frequency of p53 mutated alleles in nontumorous liver tissue from WD and hemochromatosis patients. When compared with the liver samples from normal controls, higher frequencies of G:C to T:A transversions at codon 249 ( P < 0.001) and C:G to A:T transversions and C:G to T:A transitions at codon 250 ( P < 0.001 and P &…
Catalytic Synergism in a C60IL10TEMPO2 Hybrid in the Efficient Oxidation of Alcohols
2014
A novel fullerene (5:1)hexakisadduct bearing two 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) radicals and ten 1-propyl-3-methylimida- zolium bromide moieties has been synthesized and characterized. Such an C60IL10TEMPO2 hybrid has been successfully employed as a catalyst in the se- lective oxidation of a wide series of alcohols and is highly active at just 0.1 mol% loading. Moreover, it can be easily recovered by adsorption onto a multi- layered covalently-linked SILP phase (mlc-SILP) through a "release and catch" approach and reused for up to 12 cycles without loss in efficiency. Inter- estingly, a catalytic synergistic effect of TEMPO and imidazolium bromide moieties combined in the same…
Effects of Diets Supplemented with Medicinal Mushroom Myceliated Grains on Some Production, Health, and Oxidation Traits of Dairy Ewes
2019
The beneficial properties of mushrooms’ bioactive compounds indicate their potential for use as performance-enhancing natural additives for livestock animals. A study was undertaken to evaluate the effects of diets supplemented with mushroom myceliated grains (MMGs) fed to dairy ewes on intestinal parasite load, milk production, milk fatty acid (FA) composition, and cheese oxidative stability. During an 8-week experimental period, 21 lactating Valle del Belice ewes were divided into 3 groups named MMG20, MMG10, and MMG0. Ewes in each group were fed hay ad libitum and 1.3 kg/day/head of 1 of 3 concentrates with MMGs at 20% (MMG20), 10% (MMG10), or 0% (MMG0). The ewes fed MMG20 had comparable…
A chemical approach for the reduction of beauvericin in a solution model and in food systems.
2014
Abstract Beauvericin (BEA) is a bioactive compound produced by the secondary metabolism of several Fusarium strains with a strong antibacterial, antifungal, and insecticidal activities. This study evaluated the reduction of BEA added at 25 mg/kg in phosphate buffer saline (PBS) solutions at pH of 4, 7 and 10, or to different cereal products (kernels and flours) by the bioactive compounds phenyl isothiocyanate (PITC) and benzyl isothiocyanate (BITC). The concentration of the mycotoxin was evaluated using liquid chromatography coupled to the diode array detector (LC-DAD). In solution, BEA reduction ranged from 9% to 94% on a time-dependent fashion and lower pH levels resulted in higher BEA re…
Beauvericin-induced cytotoxicity via ROS production and mitochondrial damage in Caco-2 cells.
2013
The cytotoxicity of beauvericin (BEA) on human colon adenocarcinoma (Caco-2) cells was studied as a function of time. Moreover, the oxidative damage and cell death endpoints were monitored after 24, 48 and 72 h. After BEA exposure, the IC₅₀ values ranged from 1.9 ± 0.7 to 20.6 ± 6.9 μM. A decrease in reduced glutathione (GSH; 31%) levels, as well as an increase in oxidized glutathione (GSSG, 20%) was observed. In the presence of BEA, reactive oxygen species (ROS) level was highly increased at an early stage with the highest production of 2.0-fold higher than the control that was observed at 120 min. BEA induced cell death by mitochondria-dependent apoptotic process with loss of the mitochon…
Tools for studying water vapor at high temperatures
2014
1. Kinetics and Oxidation Mechanisms 1.1 Experimental Devices that Produce Water Vapor1.2 Using the Jump Method to Understand Oxidation Mechanisms and Kinetics1.3 Detection of Breakaway Oxidation with Acoustic Emission during Thermal Oxide Scale Growth 1.4 Stress Analysis during and after Oxidation 2. Characterization 2.1 Use and Potential of Environmental SEM (ESEM) in High-Temperature Oxidation and Corrosion Studies in Wet Air 2.2 In Situ X-Ray Diffraction for Water Vapor Analyses2.3 Use of Synchrotron Beam for Evaluating the Influence of Water Vapor on the Corrosion of Metallic Materials 2.4 Raman Spectrometry2.5 In Situ Steam Oxidation Chamber Coupled to XPS 2.6 Hydrogen Profiling in Ox…
Glutathione peroxidase-1 in health and disease: from molecular mechanisms to therapeutic opportunities.
2011
Reactive oxygen species, such as superoxide and hydrogen peroxide, are generated in all cells by mitochondrial and enzymatic sources. Left unchecked, these reactive species can cause oxidative damage to DNA, proteins, and membrane lipids. Glutathione peroxidase-1 (GPx-1) is an intracellular antioxidant enzyme that enzymatically reduces hydrogen peroxide to water to limit its harmful effects. Certain reactive oxygen species, such as hydrogen peroxide, are also essential for growth factor-mediated signal transduction, mitochondrial function, and maintenance of normal thiol redox-balance. Thus, by limiting hydrogen peroxide accumulation, GPx-1 also modulates these processes. This review explor…
GADD45a physically and functionally interacts with TET1
2015
AbstractDNA demethylation plays a central role during development and in adult physiology. Different mechanisms of active DNA demethylation have been established. For example, Growth Arrest and DNA Damage 45-(GADD45) and Ten-Eleven-Translocation (TET) proteins act in active DNA demethylation but their functional relationship is unresolved. Here we show that GADD45a physically interacts – and functionally cooperates with TET1 in methylcytosine (mC) processing. In reporter demethylation GADD45a requires endogenous TET1 and conversely TET1 requires GADD45a. On GADD45a target genes TET1 hyperinduces 5-hydroxymethylcytosine (hmC) in the presence of GADD45a, while 5-formyl-(fC) and 5-carboxylcyto…
In vitro oxidation of hispidin and gallic acid by horseradish peroxidase
2023
Gallic acid and hispidin have been previously described by us as inhibitors of horseradish peroxidase (Benarous, K., Benali, F. Z., Bekhaoua, I. C., and Yousfi, M. Journal of Biomolecular Structure & Dynamics, (2021) 39(18), 7168-7180). However, additional experiments have demonstrated that under the applied assay conditions both compounds are rapidly oxidized by this enzyme. After oxidation, the components of the reaction mixture undergo complex reactions giving products with much weaker absorption at the detection wavelength. This was interpreted by us as enzyme inhibition, which, however, is only apparent. In fact, the activity of horseradish peroxidase is not affected by these compounds…