Role of oxidative stress

Plant lipoxygenases (LOXs) are a class of dioxygenases which display diverse functions in several physiological processes such as growth, development and response to biotic and abiotic stresses.Even though LOXs have been characterized from several plant species, the physiological role of seed LOXs is still unclear.With the aim to better clarify the occurrence of LOXs and their influence on hazelnut seed quality, we carried out the biochemical and molecular characterization of the main LOX isoforms expressed during seed development....

11p tumor12 20-04-2013 34 4   Download

Intravenous iron, used for the treatment of anemia in chronic renal failure andother diseases, represents a possible source of free iron in tissue cells, particularly in the liver. In this study we examined the effect of different sources of intravenous iron (IVI) on the labile iron pool (LIP) which represents the nonferritin-bound, redox-active iron that is implicated in oxidative stress and cell injury. Furthermore, we examined the role of the LIP for the synthesis of ferritin.

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The physiological role of a bifunctional enzyme, 3,4-dihydrocoumarin hydrolase (DCH), which is capable of both hydrolysis of ester bonds and organic acid-assisted bromination of organic compounds, was investigated. Purified DCH fromAcinetobacter calcoaceticusF46 cata-lysed dose- and time-dependent degradation of peracetic acid. The gene (dch) was cloned from the chromosomal DNA of the bacterium.

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GlutathioneS-transferases (GSTs) play critical roles in detoxification, response to oxidative stress, regeneration of S-thiolated proteins, and cata-lysis of reactions in nondetoxification metabolic pathways. Liver GSTs were purified from the anoxia-tolerant turtle,Trachemys scripta elegans. Purification separated a homodimeric (subunit relative molecular mass¼ 34 kDa) and a heterodimeric (subunit relative molecular mass¼32.6 and 36.8 kDa) form of GST.

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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]. ...

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The role of oxidative stress in pilocarpine-induced status epilepticus was investigated by measuring lipid peroxidation level, nitrite content, GSH con-centration, and superoxide dismutase and catalase activities in the hippo-campus of Wistar rats. The control group was subcutaneously injected with 0.9% saline. The experimental group received pilocarpine (400 mgÆkg )1 , subcutaneous). Both groups were killed 24 h after treatment.

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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.

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Metallothioneins are typically low relative molecular mass (6000–7000), sulfhydryl-rich metal-binding proteins with characteristic repeating cysteine motifs (Cys-X-Cys or Cys-Xn-Cys) and a prolate ellipsoid shape containing single a-andb-domains. While functionally diverse, they play important roles in the homeostasis, detoxification and stress response of metals. The originally reported metallothionein of the American oyster,Crassostrea virginicashowed the canonical molluscanab-domain structure. ...

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Bcp2 was identified as a putative peroxiredoxin (Prx) in the genome data-base of the aerobic hyperthermophilic archaeonSulfolobus solfataricus.Its role in oxidative stress was investigated by transcriptional analysis of RNA isolated from cultures that had been stressed with various oxidant agents.

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A number of drugs used in cancer chemotherapy induce oxidative stress by generation of oxygen free radicals (ROS) which might be an alternative mechanism for their cytotoxic effect via indu-cing apoptosis. In order to clarify the roles of antioxidants in chemotherapy, we investigated Quercetin (3,3’,4’,5,7-pentahyd-roxyflavone) and N-acetylcysteine (NAC) in different cell types treated with anticancer drugs. We studied cytotoxic activity of Topotecan alone and/or in combination with Quercetin in two human breast cancer cell lines, MCF-7 and MDA-MB-231. ...

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Prion protein (PrP) plays an important role in cell protection from oxida-tive stress due to its action as copper-chelating protein. The present study demonstrates that PrP participates in reductions of Cu 2+ to Cu + ions, and that this process results in fragmentation of protein.

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Bacterial glutathione transferases (GSTs) are part of a superfamily of enzymes that play a key role in cellular detoxification. GSTs are widely dis-tributed in prokaryotes and are grouped into several classes. Bacterial GSTs are implicated in a variety of distinct processes such as the biodegra-dation of xenobiotics, protection against chemical and oxidative stresses and antimicrobial drug resistance.

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Glutathione (GSH) plays a key role in defense against oxidative stress. The availability of GSH is ensured in tissues by systems devoted to its mainte-nance in the reduced state and by the flux of GSH and cysteine between sites of biosynthesis and sites of utilization. Little is known about the effect of oxidative stress on the distribution of low-molecular-mass thiols and their exchange rate between tissues.

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There is strong evidence thatb-amyloid (Ab) causes oxidative stress and induces mitochondrial dysfunction in the pathogenesis of Alzheimer’s dis-ease. Mitochondrial transcription factor A (Tfam) has multiple roles in the maintenance of mtDNA. To study the protective roles of Tfam against amyloid neurotoxicity, we established SH-SY5Y cell lines stably over-expressing Tfam and exposed them to 10lmAb1-42 for 24 h.

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Tribble3 (TRB3), a mammalian homolog ofDrosophilatribbles, slows cell-cycle progression, and its expression is increased in response to various stresses. The aim of this study was to investigate the role of theTRB3gene in macrophage apoptosis induced by oxidized low-density lipoprotein (ox-LDL). We found that, in human monocyte-derived macrophages, TRB3is upregulated by ox-LDL in a dose- and time-dependent manner.

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Arsenic is a strong stimulus of heme oxygenase (HO)-1 expression in experimental studies in response to oxidative stress caused by a stimulus. A functional GT-repeat polymorphism in the HO-1 gene promoter was inversely correlated to the development of coronary artery disease in diabetics and development of restenosis following angioplasty in patients. The role of this potential vascular protective factor in carotid atherosclerosis remains unclear. We previously reported a graded association of arsenic...

11p toshiba23 18-11-2011 88 2   Download

Paraplegia remains a potential complication of spinal cord ischemic reperfusion injury (IRI) in which oxidative stress induced cyclooxygenase activities may contribute to ischemic neuronal damage. Prolonged administration of vitamin E (α-TOL), as a potent biological antioxidant, may have a protective role in this oxidative inflammatory ischemic cascade to reduce the incidence of paraplegia. The present study was designed to evaluate the preventive value of α-TOL in IRI of spinal cord.

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