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H2O2 Treatment (h2o2 + treatment)
Selected AbstractsThe adaptive response of anaerobically grown Saccharomyces cerevisiae to hydrogen peroxide is mediated by the Yap1 and Skn7 transcription factorsFEMS YEAST RESEARCH, Issue 8 2008Anthony G. Beckhouse Abstract The molecular mechanisms involved in the ability of cells to adapt and respond to differing oxygen tensions are of great interest to the pharmaceutical, medical and fermentation industries. The transcriptional profiles reported in previous studies of cells grown under anaerobic, aerobic and dynamic growth conditions have shown significantly altered responses including induction of genes regulated by the oxidative stress transcription factor Yap1p when oxygen was present. The present study investigated the phenotypic changes that occur in cells when shifted from anaerobic to aerobic growth conditions and it was found through mutant analyses that the elevated activity of Yap1p during the shift was mediated by the phospholipid hydroperoxide-sensing protein encoded by GPX3. Cell viability and growth rate were unaffected even though anaerobically grown cells were found to be hypersensitive to low doses of the oxidative stress-inducing compound hydrogen peroxide (H2O2). Adaptation to H2O2 treatment was demonstrated to occur when anaerobically grown wild-type cells were aerated for a short time that was reliant on the Yap1p and Skn7p transcription factors. [source] Colour improvement of common carp (Cyprinus carpio) fillets by hydrogen peroxide for surimi productionINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 9 2008Ali Jafarpour Summary The preferred colour for surimi is white, but surimi prepared from light fillets of common carp (Cyprinus carpio) is slightly pink. Hydrogen peroxide (H2O2; 1,3% v/v) with and without sodium tri-polyphosphate (STP; 1,2% w/v) was added to a sodium carbonate bath (pH 7.0,11.5) resulting in a final pH range of 4.4,10.1 which was injected into carp fillets. After soaking and tumbling for 30 min at 4,10 °C, the fillets were evaluated for colour and water holding capacity (WHC). Fillets tumbled with treatment solution with different pH levels (7.0,11.5), but with no H2O2 or STP added, had improved colour with significantly (P < 0.05) higher L* compared with untreated fillets as the control. However, the colour improvement [(L* and colour deviation (,E)] was not significantly different (P > 0.05) within the pH levels (7.0,11.5) trialled. With increasing H2O2 levels (1,3%), fillets became lighter and ,E increased significantly (P < 0.05), especially with a 3% H2O2 treatment at pH of 10.5 (adjusted pH before H2O2 addition, actual pH after H2O2 addition was 8.2). The whiteness (L*,3b*) of kamaboko produced from treated (3% H2O2, pH 10.5) common carp light fillets was not significantly different to that of kamaboko from Alaska pollock and threadfin bream. Treatments combining H2O2 (3%) with STP (1,2%) significantly reduced the L* value obtained in comparison with fillets treated with only H2O2 (3%). Similarly, fillets treated with STP (1%) alone, resulting in lower L* values, irrespective of treatment pH (7.0,11.5). WHC, an indicator of the quality of the fillet texture, increased from 816 g/kg at pH 7.0 without STP to 841 g/kg at pH 11.5 with 1% STP. Treatment with H2O2 (without STP) decreased the WHC of the fillets. [source] Bcl-2 overexpression in hepatic stellate cell line CFSC-2G, induces a pro-fibrotic stateJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 7 2010Viridiana Y González-Puertos Abstract Background and Aim:, Development of hepatic fibrosis is a complex process that involves oxidative stress (OS) and an altered balance between pro- and anti-apoptotic molecules. Since Bcl-2 overexpression preserves viability against OS, our objective was to address the effect of Bcl-2 overexpression in the hepatic stellate cells (HSC) cell-line CFSC-2G under acetaldehyde and H2O2 challenge, and explore if it protects these cells against OS, induces replicative senescence and/or modify extracellular matrix (ECM) remodeling potential. Methods:, To induce Bcl-2 overexpression, HSC cell line CFSC-2G was transfected by lipofection technique. Green fluorescent protein-only CFSC-2G cells were used as a control. Cell survival after H2O2 treatment and total protein oxidation were assessed. To determine cell cycle arrest, proliferation-rate, DNA synthesis and senescence were assessed. Matrix metalloproteinases (MMP), tissue-inhibitor of MMP (TIMP), transglutaminases (TG) and smooth muscle a-actin (,-SMA) were evaluated by western blot in response to acetaldehyde treatment as markers of ECM remodeling capacity in addition to transforming growth factor-, (TGF-,) mRNA. Results:, Cells overexpressing Bcl-2 survived , 20% more than control cells when exposed to H2O2 and , 35% proteins were protected from oxidation, but Bcl-2 did not slow proliferation or induced senescence. Bcl-2 overexpression did not change ,-SMA levels, but it increased TIMP-1 (55%), tissue transglutaminases (tTG) (25%) and TGF-, mRNA (49%), when exposed to acetaldehyde, while MMP-13 content decreased (47%). Conclusions:, Bcl-2 overexpression protected HSC against oxidative stress but it did not induce replicative senescence. It increased TIMP-1, tTG and TGF-, mRNA levels and decreased MMP-13 content, suggesting that Bcl-2 overexpression may play a key role in the progression of fibrosis in chronic liver diseases. [source] The mechanisms underlying the anti-aging activity of the Chinese prescription Kangen-karyu in hydrogen peroxide-induced human fibroblastsJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 10 2005Akiko Satoh Our previous study showed that Kangen-karyu extract protected against cellular senescence by reducing oxidative damage through the inhibition of reactive oxygen species generation and regulation of the antioxidative status. Although these findings suggest that Kangen-karyu could delay the aging process, the mechanisms responsible for protection against aging have rarely been elucidated. Therefore, this study was focussed on the mechanisms responsible for the anti-aging activity of Kangen-karyu extract using hydrogen peroxide (H2O2)-induced human diploid fibroblasts, a well-established experimental model of cellular aging. Kangen-karyu extract exerted a protective effect against the morphological changes induced by H2O2 treatment and inhibited senescence-associated ,-galactosidase activity. In addition, the beneficial effects of Kangen-karyu extract on cell viability and lifespan indicated that Kangen-karyu extract could delay the cellular aging process. The observation that Kangen-karyu extract prevented nuclear factor kappa B (NF-,B) translocation in response to oxidative stress suggested that Kangen-karyu exerted its anti-aging effect through NF-,B modulation and prevention of H2O2 -induced overexpression of haem oxygenase-1 protein. Moreover, pretreatment with Kangen-karyu extract reduced overexpression of bax protein and prevented the mitochondrial membrane potential decline, suggesting that Kangen-karyu extract may protect mitochondria from mitochondrial oxidative stress and dysfunction. These findings indicate that Kangen-karyu is a promising potential anti-aging agent that may delay, or normalize, the aging process by virtue of its protective activity against oxidative stress-related conditions. [source] S -Allyl cysteine, S -ethyl cysteine and S -propyl cysteine alleviate oxidative stress-induced damage within PC12 cellsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 14 2008Chiu-mei Chen Abstract BACKGROUND: The PC12 cell line is a suitable model for the investigation of neurodegenerative diseases. In this study, PC12 cells were used to examine in vitro antioxidative and antiapoptotic protection by S -allyl cysteine (SAC), S -ethyl cysteine (SEC) and S -propyl cysteine (SPC). PC12 cells were treated with these agents at 5 and 10 µmol L,1 before exposure to hydrogen peroxide (H2O2). RESULTS: H2O2 treatment significantly decreased mitochondrial membrane potential (MMP) and cell viability and increased lactate dehydrogenase (LDH) release and DNA fragmentation (P < 0.05). The pre-treatments with SAC, SEC and SPC significantly and concentration-dependently elevated cell viability and MMP and lowered LDH release and DNA fragmentation (P < 0.05). H2O2 treatment also significantly increased levels of malondialdehyde (MDA), reactive oxygen species (ROS) and oxidised glutathione (GSSG) and decreased glutathione (GSH) content (P < 0.05). The pre-treatments with SAC, SEC and SPC significantly decreased subsequent H2O2 -induced formation of MDA, ROS and GSSG (P < 0.05) and also alleviated H2O2 -induced GSH depletion (P < 0.05). Finally, H2O2 treatment significantly decreased Na+ -K+ -ATPase activity and elevated caspase-3 activity (P < 0.05). The pre-treatments with SAC, SEC and SPC significantly attenuated H2O2 -induced Na+ -K+ -ATPase activity reduction and caspase-3 activity elevation (P < 0.05). CONCLUSION: The results obtained support that the three cysteine-containing compounds studied are potent neuroprotective agents. Copyright © 2008 Society of Chemical Industry [source] Proteomic profiling and identification of cofilin responding to oxidative stress in vascular smooth musclePROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 24 2006Chang-Kwon Lee Abstract We used 2-DE and MALDI-TOF/TOF to identify proteins of vascular smooth muscle cells whose expression was or was not altered by exposure to 500,,M H2O2 for 30,min. We detected more than 800 proteins on silver-stained gels of whole protein extracts from rat aortic smooth muscle strips. Of these proteins, 135 clearly unaffected and 19 having levels altered by exposure to H2O2 were identified. Protein characterization revealed that the most prominent vascular smooth muscle proteins were those with antioxidant, cytoskeletal structure, or muscle contraction. In addition, cofilin, an isoform of the actin depolymerizing factor family, shifted to its basic site on the 2-DE gel as a result of H2O2 treatment. In Western blot analysis of proteins from A7r5 aortic smooth muscle cells, the phosphorylation, but not the expression, of cofilin was decreased by H2O2 in a dose-dependent manner. The H2O2 -induced dephosphorylation of cofilin and apoptosis was inhibited by Na3VO4, an inhibitor of protein tyrosine phosphatase (PTP). These results suggest that cofilin is one of the proteins regulated by H2O2 treatment in vascular smooth muscle, and has an important role in the induction of vascular apoptosis through PTP-dependent mechanisms. [source] Antiapoptotic Cardioprotective Effect of Hypothermia Treatment Against Oxidative Stress InjuriesACADEMIC EMERGENCY MEDICINE, Issue 9 2009Chien-Hua Huang MD Abstract Objectives:, The effect of hypothermia on cardiomyocyte injury induced by oxidative stress remains unclear. The authors investigated the effects of hypothermia on apoptosis and mitochondrial dysfunction in cardiomyocytes exposed to oxidative stress. Methods:, Cardiomyocytes (H9c2) derived from embryonic rat heart cell culture were exposed to either normothermic (37°C) or hypothermic (31°C) environments before undergoing oxidative stress via treatment with hydrogen peroxide (H2O2). The degree of apoptosis was determined by annexin V and terminal deoxynucleotidyl transferase (TUNEL) staining. The amount of reactive oxygen species (ROS) was compared after H2O2 exposure between normo- and hypothermic-pretreated groups. Mitochondrial dysfunction in both groups was measured by differential reductase activity and transmembrane potential (,,m). Results:, Hydrogen peroxide induced significant apoptosis in both normothermic and hypothermic cardiomyocytes. Hypothermia ameliorated apoptosis as demonstrated by decreased annexin V staining (33 ± 1% vs. 49 ± 4%; p < 0.05) and TUNEL staining (27 ± 17% vs. 80 ±25%; p < 0.01). The amount of intracellular ROS increased after H2O2 treatment and was higher in the hypothermic group than that in the normothermic group (237.9 ± 31.0% vs. 146.6 ± 20.6%; p < 0.05). In the hypothermic group, compared with the normothermic group, after H2O2 treatment mitochondrial reductase activity was greater (72.0 ± 17.9% vs. 27.0 ± 13.3%; p < 0.01) and the mitochondria ,,m was higher (101.0 ± 22.6% vs. 69.7 ± 12.9%; p < 0.05). Pretreatment of cardiomyocytes with the antioxidant ascorbic acid diminished the hypothermia-induced increase in intracellular ROS and prevented the beneficial effects of hypothermia on apoptosis and mitochondrial function. Conclusions:, Hypothermia at 31°C can protect cardiomyocytes against oxidative stress,induced injury by decreasing apoptosis and mitochondrial dysfunction through intracellular ROS-dependent pathways. [source] Effects on Lipid Peroxidation and Antioxidative Enzymes of Euonymus alatus in Cultured Rat HepatocytesBASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 1 2009Kyung-Woon Kim In this paper, we investigate the effects of E. alatus on cultured hepatocyte cell system and lipid peroxidation in hydrogen peroxide (H2O2) treatment conditions. The study covers the physiological activity (the antioxidative activity and the nitrite-scavenging effect) of E. alatus. H2O2 that can produce intracellular free radical was used for inducer of the peroxidation of cellular lipids. Treatment of E. alatus attenuated in cell killing enhanced by increasing concentrations of H2O2. The increased malondialdehyde level induced by H2O2 treatment was reduced by pre-treatment of E. alatus. Furthermore, addition of E. alatus in cell culture medium significantly reduced cell killing and content of intracellular antioxidants. Changes in nitrite-scavenging effect of E. alatus at various concentrations (5,25 mg/ml) and various pH levels (pH 1.2, 4.2 and 6.0) were also observed. The present study was also done to investigate the effects of E. alatus on cultured hepatocyte cell system, H2O2 -induced cytotoxicity and antioxidative enzyme activities, including catalase, superoxide dismutase, glutathione peroxidase and glutathione S-transferase in H2O2 treatment conditions. E. alatus treatment had significant protective or elevating activities on these antioxidative enzyme activities compared to a normal group. The results indicate that E. alatus provides a strong antioxidant protection of cells against H2O2 -induced oxidative stress. [source] Accumulation of deoxynivalenol and its 15-acetylated form is significantly modulated by oxidative stress in liquid cultures of Fusarium graminearumFEMS MICROBIOLOGY LETTERS, Issue 1 2006Nadia Ponts Abstract Liquid cultures of Fusarium graminearum were supplemented with H2O2 or other oxidative compounds. The accumulation kinetics of the resulting trichothecenes were monitored. At non-lethal concentrations, the H2O2 treatments modulated toxin accumulation, dependent on the method of supplementation. When H2O2 was added at the same time as the inoculation, higher levels of toxins accumulated 30 days later. Conversely, adding H2O2 2 or 7 days after inoculation had little effect. When H2O2 was added daily over the course of the culture, the accumulation of trichothecenes was rapidly and strongly enhanced. The fungus may adapt to oxidative stress when the first exposure to H2O2 occurs at the beginning of the culture course. The highest toxin levels were measured when the H2O2 was added daily. The importance of the first hours of culture was confirmed: pre-treating conidia with H2O2 does not affect their germination kinetics but leads to a reduction in the yield of trichothecenes 40 days later. The H2O2 regulation of this trichothecene accumulation may be specific, as paraquat, another pro-oxidant compound, inhibits their production. Since H2O2 is a major component of the oxidative burst occurring in pathogen/host interactions, these data support the theory that trichothecenes may act as virulence factors. [source] Catalase inhibition alters suberization and wound healing in potato (Solanum tuberosum) tubersPHYSIOLOGIA PLANTARUM, Issue 3 2007Mohammed Bajji In response to wounding, potato (Solanum tuberosum L.) tubers generate hydrogen peroxide (H2O2) in association with suberization, a critical phase of the wound-healing process. In the present study, the effect of aminotriazole (AT), a catalase (CAT, EC 1.11.1.6) inhibitor, on cut tubers was investigated using fresh weight (FW) loss and pathogen attack symptoms as indicators of wound-healing efficiency. Seven days after treatment, AT-treated tuber halves lost more FW and developed infection signs compared with the controls. Thiourea, another CAT inhibitor, as well as exogenous H2O2 treatments induced the same effects as AT suggesting that the alteration of the wound healing may be caused by CAT inhibition and the resulting accumulation of H2O2. Using transgenic tubers, FW losses 1 week after wounding were either higher (CAT repression) or lower (CAT overexpression) than those of the wild-type. When tuber halves were allowed to wound heal for different periods before treatment, AT had no effect on the progress of their wound healing if wound-healed for at least 3 days. This implies that AT may affect early wound-healing-related events, especially those occurring before or during suberization. A time-course analysis of the effects of AT treatment on wounded tuber tissues revealed that AT prevented the deposition of the polyphenolic domain of suberin in association with CAT inhibition and H2O2 accumulation. These data are important in identifying factors that may be required to regulate suberization and contribute to a better understanding of this critical process to hasten its rate and limit wound-related losses in stored potato tubers. [source] | ||||||||||||||||