Reactive oxygen species

The objective of this work is to experimentally investigate the effect of the oxygen potential on the fuel and FP chemical behaviour in conditions representative of a severe accident. More specifically, the speciation of Cs, Mo and Ba is investigated.

10p christabelhuynh 29-05-2020 11 3   Download

The Na+-translocating NADH:quinone oxidoreductase (Na+-NQR) from Vibrio alginolyticus was inactivated by reactive oxygen species. Highest Na+-NQR activity was observed in anaerobically prepared membranes that exhibited 1 : 1 coupling of NADH oxidation and Q reduction activities (1.6 UÆmg)1). Optical and EPR spectroscopy documented the presence of b-type cytochromes, a [2Fe)2S] cluster and an organic radical signal in anaerobically pre- pared membranes from V. alginolyticus.

6p research12 01-06-2013 46 4   Download

Reactive oxygen species (ROS) are products of normal metabolic activities and are thought to be the cause of many diseases. A selenium-containing single-chain abzyme 2F3 (Se-2F3-scFv) that imitates glutathione peroxidase has been produced which has the capacity to remove ROS. To evaluate the antioxidant ability of Se-2F3-scFv, we con-structeda ferrous sulfate/ascorbate (Vc/Fe 2+ )-inducedmito-chondrial damage model system and investigated the capacity of Se-2F3-scFv to protect mitochondria from oxi-dative damage.

6p tumor12 20-04-2013 33 4   Download

Exposure of mammalian cells to oxidant stress causes early (iron catalysed) lysosomal rupture followed by apoptosis or necrosis. Enhanced intracellular production of reactive oxygen species (ROS), presumably of mitochondrial origin, is also observed when cells are exposed to nonoxidant pro-apoptotic agonists of cell death. We hypothesized that ROS generation in this latter case might promote the apoptotic cascade and could arise from effects of released lysosomal materials on mitochondria.

9p tumor12 20-04-2013 30 1   Download

Ascorbic acid is often regarded as an antioxidantin vivo, where it protects against cancer by scavenging DNA-dam-aging reactive oxygen species. However, the detailed mech-anism of the action of ascorbic acid on genetic DNA is still unclear. We examined the effect of ascorbic acid on the higher-order structure of DNA through real-time observa-tion by fluorescence microscopy. We found that ascorbic acid generates a pearling structure in single giant DNA molecules, with elongated and compact regions coexisting along a molecular chain. ...

6p tumor12 20-04-2013 32 5   Download

The peroxidase–oxidase reaction is known to involve react-ive oxygen species as intermediates. These intermediates inactivatemany types of biomolecules, including peroxidase itself. Previously,wehave shown that oscillatorydynamics in the peroxidase–oxidase reaction seem to protect the enzyme frominactivation. It was suggested that this is due to a lower average concentration of reactive oxygen species in the oscillatory state compared to the steady state. Here, we studied the peroxidase–oxidase reaction with either 4-hydroxybenzoic acid or melatonin as cofactors. ...

9p fptmusic 16-04-2013 45 4   Download

Photodynamic treatment (PDT) is an emerging therapeutic procedure for the management of cancer, based on the use of photosensitizers, compounds that generate highly reactive oxygen species (ROS) on irradiation with visible light. The ROS generated may oxidize a variety of bio-molecules within the cell, loaded with a photosensitizer. The high reactivity of these ROS restricts their radius of action to 5–20 nm from the site of their generation.

7p fptmusic 12-04-2013 44 3   Download

Oxidative stress and imbalance between free radical generation and detoxi-fication may play a pivotal role in the pathogenesis of Leber’s hereditary optic neuropathy (LHON). Mitochondria, carrying the homoplasmic 11778⁄ND4, 3460⁄ND1 and 14484⁄ND6 mtDNA point mutations associ-ated with LHON, were used to generate osteosarcoma-derived cybrids. Enhanced mitochondrial production of reactive oxygen species has recently been demonstrated in these cybrids [Beretta S, Mattavelli L, Sala G, Trem-olizzo L, Schapira AHV, Martinuzzi A, Carelli V & Ferrarese C (2004) Brain127, 2183–2192]. ...

0p awards 05-04-2013 44 4   Download

Metformin (1,1-dimethylbiguanide) is an antihyperglycae-mic drug used to normalize glucose concentrations in type 2 diabetes. Furthermore, antioxidant benefits have been reported in diabetic patients treated with metformin. This work was aimed at studying the scavenging capacity of this drug against reactive oxygen species (ROS) like Æ OH and O Æ
2 -free radicals. ROS were produced by gamma radio-lysis of water. The irradiated solutions of metformin were analyzed by UV/visible absorption spectrophotometry.

8p awards 05-04-2013 60 1   Download

Three pairs of parental (q + ) and established mitochondrial DNAdepleted (q 0 ) cells, derived frombone, lungandmuscle were used to verify the influence of the nuclear background and the lack of efficient mitochondrial respiratory chain on antioxidant defences and homeostasis of intracellular reactive oxygen species (ROS).

11p awards 05-04-2013 45 4   Download

The retinal pigment epithelium (RPE) is essential for main-tenance of photoreceptors and normally functions under conditions enriched with reactive oxygen species. RPE therefore expresses various defense enzymes against oxida-tive stress, including heme oxygenase-1 (HO-1). HO-1 catalyzes heme breakdown to release iron, carbon monox-ide, and biliverdin, which is reduced to bilirubin, a potent radical scavenger. HO-1 expression is induced by various environmental factors, which has been established as a def-ense mechanism....

9p awards 05-04-2013 41 4   Download

The extracellular signal regulated protein kinases (ERK1/2) are essential for normal development and functional plasti-city of the central nervous system. However, a growing number of recent studies in models of cerebral ischemia, brain trauma and neurodegenerative diseases implicate a detrimental role for ERK1/2 signaling during oxidative neuronal injury. Neurons undergoing oxidative stress-rela-ted injuries typically display a biphasic or sustained pattern of ERK1/2 activation.

7p dell39 03-04-2013 40 3   Download

The interplay among reactive oxygen species (ROS) formation, elevated intracellular calcium concentration and mitochondrial demise is a recurring theme in research focusing on brain pathology, both for acute and chronic neurodegenerative states. However, causality, extent of contribution or the sequence of these events prior to cell death is not yet firmly established.

18p dell39 27-03-2013 41 3   Download

Peroxiredoxins belong to a family of antioxidant proteins that neutralize reactive oxygen species. One member of this family, peroxiredoxin I (PRDX1), suppresses DNA oxidation. Peroxiredoxin V (PRDX5) has been cloned as a transcriptional corepressor, as a peroxisomal⁄mitochondrial antioxidant protein, and as an inhibitor of p53-dependent apoptosis.

11p inspiron33 26-03-2013 46 4   Download

We recently reported that the transient expression of polyglutamine tracts of various size in exon 1 of the huntingtin polypeptide (httEx1) generated abnormally high levels of intracellular reactive oxygen species that directly contributed to cell death. Here, we compared the protection generated by heat shock proteins to that provided by the antioxidant agentN-acetyl-l-cysteine.

18p inspiron33 25-03-2013 45 5   Download

Inhibition of the mitochondrial adenine nucleotide translocator (ANT) by long-chain acyl-CoA esters has been proposed to contribute to cellular dys-function in obesity and type 2 diabetes by increasing formation of reactive oxygen species and adenosine via effects on the coenzyme Q redox state, mitochondrial membrane potential (Dw) and cytosolic ATP concentrations.

15p inspiron33 23-03-2013 55 4   Download

Although essentially unknown, several functions are hypothesized for neu-roglobin and cytoglobin, two new members of the globin family. In this article, we try to shed more light on their possible roles in hypoxia and detoxification of reactive oxygen speciesin vivo. Thijs

6p galaxyss3 21-03-2013 36 4   Download

Ascorbate peroxidase (APX) isoforms localized in the stroma and thyla-koid membrane of chloroplasts play a central role in scavenging reactive oxygen species generated by photosystems. These enzymes are inactivated within minutes by H2O2 when the reducing substrate, ascorbate, is deple-ted.

8p galaxyss3 19-03-2013 31 3   Download

Cyclosporin A induces closure of the mitochondrial permeability transition pore. We aimed to investigate whether this closure results in concomitant increases in mitochondrial membrane potential (DWm) and the produc-tion of reactive oxygen species.

10p galaxyss3 19-03-2013 30 5   Download

Onchocerciasis or river blindness, caused by the filarial nematodeOncho-cerca volvulus, is the second leading cause of blindness due to infectious diseases. The protective role of the omega-class glutathione transferase 3 from O. volvulus(OvGST3) against intracellular and environmental reactive oxygen species has been described previously.

16p galaxyss3 07-03-2013 44 2   Download