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Query: EC:1.9.3.1 (
cytochrome oxidase
)
8,822
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The possible relation between respiratory capacity and antioxidant capacity and susceptibility to oxidative stress of the liver has been investigated in Rattus norvegicus, Gallus gallus domesticus, Lacerta s. sicula, and Rana esculenta. Accordingly, we measured oxygen consumption and
cytochrome oxidase
activity,
glutathione peroxidase
and glutathione reductase activity and overall antioxidant capacity, and lipid peroxidation and response to oxidative stress in vitro in liver. The order of liver oxygen consumption and
cytochrome oxidase
activity among the different species was rat > chick > lizard > frog. The antioxidant defenses supplied by the combined action of
glutathione peroxidase
and glutathione reductase were not adapted to the respiratory capacities. In particular, there was no correlation either between the activities of two enzymes or between their activities and oxygen consumption. In contrast, the overall antioxidant capacity of the liver appeared to be related to its oxidative capacity, and the malondialdehyde formation, an indirect measure of lipid peroxidation, was inversely related to antioxidant capacity. The response to oxidative stress in vitro indicated that the liver susceptibility to oxidative challenge is higher in ectothermic than in endothermic species. Such higher susceptibility appeared to depend on both lower antioxidant capacity and higher levels of free radical producing species. This finding is apparently in contrast with a higher content of cytochromes in endotherms, which are able to determine both respiratory characteristics and sensitivity to pro-oxidants. However, it could indicate the existence of species-related differences in the tissue content of either preventive antioxidants or hemoproteins able to trap the radicals produced at their active center. J. Exp. Zool. 284:610-616, 1999.
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PMID:Protection against oxidative stress in liver of four different vertebrates. 1053 47
Supplementation of human mononuclear cells with 3 and 6 mM of lipoic acid produces an inhibition of the antioxidant adaptive response triggered by treatment with UV-B light (0.30 W/m2 for 15 min). Supplementation with 1.5 mM of lipoic acid gives no conclusive results. The adaptive response is characterized by an increase in the activities of superoxide dismutase, catalase,
glutathione peroxidase
and DT-diaphorase. Catalase (5.5 +/- 0.6 pmol/mg prot) increases its activity by up to 22 +/- 3 pmol/mg prot, after irradiation with UV-B. Supplementation with 3 and 6 mM of lipoic acid completely inhibits the adaptive response. The activities of the membrane-bound mitochondrial enzymes succinate dehydrogenase and
cytochrome oxidase
do not increase after UV-B exposure. Moreover, their activities are found to decrease and the addition of lipoic acid does not prevent this effect. The inhibition of the antioxidant response by lipoic acid in human cells appears as indirect evidence of the existence of oxidative stress in the development of this response. As lipoic acid behaves as an effective antioxidant, it seems that its action decreases the intracellular oxidative signals necessary to develop the adaptive response in human mononuclear cells.
...
PMID:Antioxidant adaptive response of human mononuclear cells to UV-B: effect of lipoic acid. 1094 75
The influence of thyroxine on activity of enzymes of energy metabolism (hexokinase, phosphofructokinase, pyruvate kinase, laktate dehydrogenase, glucose-6-phosphate dehydrogenase, NADP-isocitrate dehydrogenase,
cytochrome-c oxidase
) and antioxidative system (
glutathione peroxidase
, glutathione reductase, superoxide dismutase) of neonatal piglet neutrophils was investigated. It has been found, that after durable injections of hormone (4 mg/kg body weight) the increase of glycolytic enzymes activities as well as aerobic energy pathway catalyzers took place. Simultaneously the augmentation of superoxide dismutase reaction occurred after the thyroxine treatment. Such effect might represent an important link in compensatory mechanism, which prevents the destructive action of reactive oxygen species.
...
PMID:[The effect of thyroxine on the enzymatic activity of the energy metabolism and antioxidant system in the neutrophilic granulocytes of piglets]. 1105 92
Dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin; TCDD) causes an oxidative stress response in liver and several extrahepatic tissues. The subcellular sources and underlying mechanisms of dioxin-induced reactive oxygen, however, are not well understood. In this study, we examined whether mitochondria, organelles that consume the majority of cellular oxygen, might be a source of dioxin-induced reactive oxygen. Female C57BL/6 mice were treated with dioxin (15 microg/kg body wt ip) on 3 consecutive days, and liver mitochondria were examined at 1, 4, and 8 weeks after the first treatment. Mitochondrial aconitase activity, an enzyme inactivated by superoxide, was decreased by 44% at 1 week, 22% at 4 weeks, and returned to control levels at 8 weeks. Dioxin elevated succinate-stimulated mitochondrial H2O2 production twofold at 1 and 4 weeks; H2O2 production remained significantly elevated at 8 weeks. The enhanced H2O2 production was due to neither increased Mn-superoxide dismutase activity nor decreased mitochondrial
glutathione peroxidase
activity. Dioxin treatment augmented mitochondrial glutathione, but not glutathione disulfide levels, a result that might be explained by increased mitochondrial glutathione reductase activity. Liver ATP levels were significantly lowered at 1 and 4 weeks, the peak times of mitochondrial reactive oxygen production. Increased dioxin-stimulated reactive oxygen at 1 and 4 weeks did not appear to be related to the observed decrease in
cytochrome oxidase
activity, since State 3 and State 4 respiration were not diminished. To our knowledge, this is the first report to show that dioxin increases mitochondrial respiration-dependent reactive oxygen production, which may play an important role in dioxin-induced toxicity and disease.
...
PMID:Dioxin increases reactive oxygen production in mouse liver mitochondria. 1246 Jul 39
We report here that estrogen (E(2)) modulates mitochondrial function in the vasculature. Mitochondrial dysfunction is implicated in the etiology of vascular disease; thus, vasoprotection by estrogen may involve hormonal effects on the mitochondria. To test this hypothesis, mitochondria were isolated from cerebral blood vessels obtained from ovariectomized female rats, with or without E(2) replacement. Estrogen receptor-alpha (ER-alpha) was detected in mitochondria by immunoblot and confocal imaging of intact vessels. E(2) treatment in vivo increased the levels of specific proteins in cerebrovascular mitochondria, such as ER-alpha, cytochrome c, subunit IV of
complex IV
, and manganese superoxide dismutase, all encoded in the nuclear genome, and subunit I of
complex IV
, encoded in the mitochondrial genome. Levels of
glutathione peroxidase
-1 and catalase, however, were not affected. Functional assays of mitochondrial citrate synthase and
complex IV
, key rate-limiting steps in energy production, showed that E(2) treatment increased enzyme activity. In contrast, mitochondrial production of hydrogen peroxide was decreased in vessels from E(2)-treated animals. In vitro incubation of cerebral vessels with 10 nM 17beta-estradiol for 18 h also elevated levels of mitochondrial cytochrome c. This effect was blocked by the estrogen receptor antagonist fulvestrant (ICI-182,780, Faslodex) but was unaffected by inhibitors of nitric-oxide synthase or phosphoinositide-3-kinase. Nuclear respiratory factor-1 protein, a primary regulator of nuclear gene-encoded mitochondrial genes, was significantly increased by long-term estrogen treatment in vivo. In summary, these novel findings suggest that vascular protection by E(2) is mediated, in part, by modulation of mitochondrial function, resulting in greater energy-producing capacity and decreased reactive oxygen species production.
...
PMID:Estrogen increases mitochondrial efficiency and reduces oxidative stress in cerebral blood vessels. 1599 67
The antioxidant activity of a novel artificial
glutathione peroxidase
-like enzyme, selenium-containing glutathione 5-transferase from Lucilia cuprina (seleno-LuGST1-1), was studied by using a ferrous sulfate/ascorbate-induced mitochondrial damage model system. Swelling of mitochondria, lipid peroxidation, and
cytochrome-c oxidase
activity were selected to evaluate the preservation of mitochondrial integrity in this system. Seleno-LuGST1-1 could effectively protect the mitochondria against oxidative damage in a dose-dependent manner and exhibited both higher catalytic activity and greater antioxidant ability than the classic mimic, 2-phenyl-1,2-benziososelenazol-3(2H)-one (Ebselen). This novel artificial biocatalyst therefore may have great potential for pharmacologic application in the treatment of reactive oxygen species-related diseases.
...
PMID:Protection of mitochondrial integrity from oxidative stress by selenium-containing glutathione transferase. 1625 90
The effect of gender and caloric restriction on mitochondrial content and oxidative-phosphorylative capacities has been investigated in rat gastrocnemius muscle. Muscle protein, mitochondrial protein and DNA contents, enzymatic activities of mitochondrial oxidative and phosphorylative system, mitochondrial antioxidant enzymes, protein levels of
complex IV
(subunit I and IV) and ATPase, and the gene and protein expression of mitochondrial transcription factor A (TFAM), involved in mitochondrial replication and transcription, were measured in rats of both genders fed ad libitum and subjected to three months of 40% caloric restriction. Compared to males, gastrocnemius muscle of female rats showed higher mitochondrial DNA and protein contents, TFAM protein level, oxidative and phosphorylative machinery and activities, and
glutathione peroxidase
activity. In conclusion, the present data show a clear gender dimorphism in rat muscle mitochondrial features, which could explain the higher facility of females to adapt to altered metabolic energy situations.
...
PMID:Skeletal muscle of female rats exhibit higher mitochondrial mass and oxidative-phosphorylative capacities compared to males. 1731 Jan 14
Reactive oxygen species may contribute to the pathogenesis of muscular dystrophy. High intensity exercise clearly induces muscle damage in mdx mice; however, the effects of low intensity exercise training (LIT) on mdx muscle are less clear. We examined the effect of LIT on markers of oxidative stress (malondialdehyde and protein carbonyls), antioxidant (superoxide dismutase, catalase, and
glutathione peroxidase
), and mitochondrial (2-oxoglutarate dehydrogenase and
cytochrome oxidase
) enzymes in skeletal muscle of mdx and wild-type mice. Mdx and wild-type mice were allocated to LIT and sedentary groups. Malondialdehyde levels were higher in white muscle from sedentary mdx as compared to both sedentary and LIT wild-type mice (P<0.001). Protein carbonyl content was higher in white and red muscle of mdx versus wild-type mice (P<0.05). LIT was associated with lower levels of malondialdehyde and protein carbonyls in white muscle of mdx mice (decreased 38 and 44%, P<0.001 and P<0.01, respectively). Antioxidant and mitochondrial enzyme activities were higher in white muscle of mdx than in wild-type mice (P<0.05). LIT in mdx mice induced physiological adaptation resulting in lower levels of markers of oxidative stress that were not different than those from wild type. These results are of relevance for therapeutic exercise in patients with dystrophinopathy where exercise prescription remains controversial.
...
PMID:Low intensity training decreases markers of oxidative stress in skeletal muscle of mdx mice. 1756 Nov 3
Acute exercise in mice induces intestinal lymphocyte (IL) apoptosis. Freewheel running reduces apoptosis and forced exercise training increases splenocyte antioxidant levels. The purpose of this study was to examine the effect of freewheel running and acute exercise on mouse IL numbers and concentrations of apoptosis and antioxidant proteins and pro-inflammatory cytokines in IL. Female C57BL/6 mice had access to in-cage running wheels (RW) or cages without wheels (NRW) for 16 weeks and were randomized at the end of training to no exercise control (TC) or to treadmill exercise with sacrifice after 90 min of running (TREAD; 30 min, 22 m min(-1); 30 min, 25 m min(-1); 30 min, 28 m min(-1); 2 degrees slope). IL were analyzed for pro-(caspase 3 and 7) and anti-(Bcl-2) apoptotic proteins, endogenous antioxidants (
glutathione peroxidase
: GPx; catalase: CAT) and the pro-inflammatory cytokine, TNF-alpha. RW mice had higher
cytochrome oxidase
(p<0.001) and citrate synthase (p<0.01) activities in plantaris and soleus muscles and higher GPx and CAT expression in IL (p<0.05) (indicative of training) compared with NRW mice. TNF-alpha expression was lower (p<0.05) and IL numbers higher (p<0.05) in RW vs. NRW mice. No training effect was observed for apoptotic protein expression, although TREAD resulted in higher caspase and lower Bcl-2. These results suggest that freewheel running in mice for 16 weeks enhances antioxidant and reduces TNF-alpha expression in IL but does not reduce pro-apoptotic protein expression after acute exercise. Results are discussed in terms of implications for inflammatory bowel diseases where apoptotic proteins and TNF-alpha levels are elevated.
...
PMID:Voluntary exercise training in mice increases the expression of antioxidant enzymes and decreases the expression of TNF-alpha in intestinal lymphocytes. 1948 47
Oral toxicity of several cyanogens and their reversal by alpha-ketoglutarate (A-KG; oral) were studied in rats. LD(50) of acetonitrile (ATCN), acrylonitrile (ACN), malononitrile (MCN), propionitrile (PCN), sodium nitroprusside (SNP), and succinonitrile (SCN) was 4891, 143.3, 69.8, 122.9, 69.8 and 488.7 mg/kg, respectively while the protection index of A-KG (ratio of LD(50) of cyanogens in the presence or absence of A-KG) was>2.0 against MCN (7.6), PCN (2.7) and SNP (3.6) only. We further studied the efficacy of A-KG against acute toxicity of these three cyanogens (0.75 LD(50)) on various hematological and biochemical variables in blood and soft tissues 24h post-exposure. We observed increase in white blood cells (SNP), plasma alanine (PCN, SNP) and aspartate (PCN) aminotransferase, lactate dehydrogenase (MCN, PCN, SNP), Na(+) (MCN, PCN) and cyanide (PCN), and decrease in K(+) (MCN, SNP) accompanied by an increase in brain, kidney and liver malondialdehyde (PCN), decrease in brain
glutathione peroxidase
, glutathione reductase (PCN, SNP), reduced glutathione (MCN, PCN, SNP) and
cytochrome oxidase
(PCN), liver rhodanese (PCN, SNP), and kidney
cytochrome oxidase
(PCN). The study indicates that (i) PCN was most toxic among all the cyanogens and (ii) beside cyanide, A-KG could be considered as an effective antidote for cyanogens.
...
PMID:Acute toxicity of some synthetic cyanogens in rats and their response to oral treatment with alpha-ketoglutarate. 1953 83
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