Search results for "OXIDASE"
showing 10 items of 927 documents
Effect of corn oil and vitamin E on the oxidative status of adipose tissues and liver in rat
2003
Abstract The diet is usually formed of a varying antioxidant and fatty acid content acquired from oils. The purpose of this study was to determine the effects of corn oil-rich diet supplemented or not with vitamin E on oxidative damage and antioxidant status in liver and adipose tissue of rat. Male Wistar rats were fed during 4 weeks with a hyperlipidic diet. The groups fed with hyperlipidic diets showed lower activity levels than the control groups with the exception of superoxide dismutase and glutathione peroxidase in brown adipose tissue. Supplementation of the control group with vitamin E (CE) did not produce any significant changes in the superoxide dismutase and catalase levels, but …
N-3 fatty acids modulate antioxidant status in diabetic rats and their macrosomic offspring.
2006
We investigated the role of dietary n-3 polyunsaturated fatty acids (n-3 PUFA) in the modulation of total antioxidant status in streptozotocin (STZ)-induced diabetic rats and their macrosomic offspring. Female wistar rats, fed on control diet or n-3 PUFA diet, were rendered diabetic by administration of five mild doses of STZ on day 5 and were killed on days 12 and 21 of gestation. The macrosomic (MAC) pups were killed at the age of 60 and 90 days. Lipid peroxidation was measured as the concentrations of plasma thiobarbituric acid reactive substances (TBARS), and the total antioxidant status was determined by measuring (i) plasma oxygen radical absorbance capacity (ORAC), (ii) plasma vitami…
Anti-inflammatory Function of High-Density Lipoproteins via Autophagy of IκB Kinase
2015
Background & Aims: Plasma levels of high-density lipoprotein (HDL) cholesterol are frequently found decreased in patients with inflammatory bowel disease (IBD). Therefore, and because HDL exerts anti-inflammatory activities, we investigated whether HDL and its major protein component apolipoprotein A-I (apoA-I) modulate mucosal inflammatory responses in vitro and in vivo. Methods: The human intestinal epithelial cell line T84 was used as the in vitro model for measuring the effects of HDL on the expression and secretion of tumor necrosis factor (TNF), interleukin-8 (IL-8), and intracellular adhesion molecule (ICAM). Nuclear factor-κB (NF-κB)-responsive promoter activity was studied by …
Regeneration of the cell wall in protoplasts of Candida albicans. A cytochemical study using wheat germ agglutinin and concanavalin A.
1988
To assess the dynamics of synthesis of the wall by regenerating Candida albicans protoplasts deposition of chitin and mannoproteins were investigated ultrastructurally using wheat germ agglutinin conjugated with either horseradish peroxidase or colloidal gold, and Concanavalin A coupled to ferritin respectively. Freshly prepared protoplasts lacked wheat germ agglutinin receptor sites but after 1-2 h of regeneration, they were detected. After 4-5 h of regeneration, the cell wall showed a discrete structure which was only labelled with wheat germ agglutinin in thin sections. At this stage of regeneration the outermost layer of the wall was labelled with clusters of Concanavalin A-ferritin par…
Evolution of anthocyanin profile from grape to wine
2010
<p style="text-align: justify;"><strong>Aims</strong>: This study aimed at acquiring knowledge of the evolution of anthocyanins from grape to wine and the possibility of deducing the varietal origin of a wine from its anthocyanin profile.</p><p style="text-align: justify;"><strong>Methods and results</strong>: The anthocyanin « fingerprint », or profile, of a series of autochthonous Sicilian accessions and their respective young wines was determined by HPLC-DAD in 2008. Data were evaluated by taking into account the evolution of the percentages of side-ring dioxygenated and tri-oxygenated anthocyanins, the ratio between acetylated and p-coumaroylate…
Wine-making with protection of must against oxidation in a warm, semi-arid terroir
2016
In order to defend varietal aromas from oxidation before alcoholic fermentation, two musts were prepared from white grapes pre-cooled and added with ascorbic acid and solid CO2 (trial ACO2) or SO2 (trial BSO2). Experiments were performed with grapes of a white grape variety indigenous to western Sicily, the wines from which, obtained by vinification of musts protected from oxidation and poor in copper, as previously proven, have aroma descriptors ascribed to passion fruit and grapefruit skin. The smaller content in flavanols in the ACO2 trial, demonstrated that the use of solid CO2, instead of SO2, reduced the extraction of such polyphenols from grape solids. The higher content in hydroxyci…
Polyphenoloxidase from Riesling and Dornfelder wine grapes (Vitis vinifera) is a tyrosinase.
2015
Abstract Polyphenoloxidases (PPO) of the type-3 copper protein family are considered to be catecholoxidases catalyzing the oxidation of o-diphenols to their corresponding quinones. PPO from Grenache grapes has recently been reported to display only diphenolase activity. In contrast, we have characterized PPOs from Dornfelder and Riesling grapes which display both monophenolase and diphenolase activity. Ultracentrifugation and size exclusion chromatography indicated that both PPOs occur as monomers with Mr of about 38 kDa. Non-reducing SDS–PAGE shows two bands of about 38 kDa exhibiting strong activity. Remarkably, three bands up to 60 kDa displayed only very weak PPO activity, supporting th…
Induction of mitochondrial xanthine oxidase activity during apoptosis in the rat mammary gland
2006
Oxidative stress is an important signal for apoptosis to start. So far the mitochondrial respiratory chain has been considered as the major, if not the only, cause of such stress. Here we report that this is not the case. Xanthine oxidase, a O2(-) and H2O2 generating enzyme which is important in causing significant oxidative stress in the cytosol, is also present in the mitochondrial fraction of rat mammary gland. After weaning, during the involution of the mammary gland, massive apoptosis occurs. Mitochondrial xanthine oxidase activity increases and high mitochondrial H2O2 production takes place. Inhibition of xanthine oxidase activity by allopurinol, a specific inhibitor of xanthine oxida…
Flavonols and flavan-3-ols as modulators of xanthine oxidase and manganese superoxide dismutase activity.
2014
Experiments were performed to assess the dose-dependent effects of quercetin, kaempferol, (+) catechin, and (-) epicatechin on superoxide radical production through the modulation of manganese superoxide dismutase and xanthine oxidase activities. The experiments were carried out at flavanoid concentrations ranging from 1 µM to 100 µM. This investigation highlighted that flavonols induced opposite effects on superoxide radical production at different doses, i.e. pro-oxidant at the highest concentration (100 µM) and anti-oxidant at the lowest concentration (1 µM). Similar behaviors were observed for xanthine oxidase with flavan-3ols. The diastereoisomer (the catechin) acted as a stronger radi…
Vascular oxidative stress, nitric oxide and atherosclerosis.
2014
In the vascular wall, reactive oxygen species (ROS) are produced by several enzyme systems including NADPH oxidase, xanthine oxidase, uncoupled endothelial nitric oxide synthase (eNOS) and the mitochondrial electron transport chain. On the other hand, the vasculature is protected by antioxidant enzyme systems, including superoxide dismutases, catalase, glutathione peroxidases and paraoxonases, which detoxify ROS. Cardiovascular risk factors such as hypercholesterolemia, hypertension, and diabetes mellitus enhance ROS generation, resulting in oxidative stress. This leads to oxidative modification of lipoproteins and phospholipids, mechanisms that contribute to atherogenesis. In addition, oxi…