Removal Of Peroxide Research Articles

Influence of feedstocks and modification methods on biochar’s capacity to activate hydrogen peroxide for tetracycline removal

Three types of raw biochar (i.e. CBC, OBC, PBC produced from cornstalk, orange peel and peanut hull, respectively) and the modified ones (i.e., KMnO4-, KOH- and H3PO4-treatment) were employed to activate H2O2 for the removal of tetracycline (TC). The effects of pyrolysis temperatures, H2O2 concentration and initial pH were examined. TC removal by raw biochars w/o H2O2 was dependent on the feedstock and pyrolysis temperature of biochar, but the removal efficiency was still quite low under optimum conditions. The KMnO4-treatment significantly enhanced the adsorption of TC on all three biochars, but only enhanced the TC removal by CBC + H2O2. The KOH-treatment had insignificant effect on the adsorption of TC on biochar, but improved the performance of CBC/PBC + H2O2. The H3PO4-treatment had a negative impact on TC removal by biochar w/o H2O2. Overall, H2O2 could either enhance or decrease the TC removal by biochar, depending on biochar type, H2O2 concentration and solution pH.

Peroxiredoxin expression and redox status in neutrophils and HL-60 cells

Peroxiredoxins (Prxs) are thiol peroxidases with a key role in antioxidant defense and redox signaling. They could be important in neutrophils for handling the large amount of oxidants that these cells produce. We investigated the redox state of Prx1 and Prx2 in HL-60 promyelocytic cells differentiated to neutrophil-like cells (dHL-60) and in human neutrophils. HL-60 cell differentiation with dimethyl sulfoxide caused a large decrease in expression of both Prxs, and all-trans retinoic acid also decreased Prx1 expression. Prx1 was mostly reduced in dHL-60 cells. NADPH oxidase activation by phorbol myristate acetate (PMA) or ingestion of Staphylococcus aureus induced rapid oxidation to disulfide-linked dimers, and eventually hyperoxidation. The NADPH oxidase inhibitor, diphenyleneiodonium, prevented Prx1 dimerization in stimulated dHL-60 cells, and decreased the extent of oxidation under resting conditions. In contrast, Prx1 and Prx2 were present in neutrophils from human blood as disulfides, and PMA or S. aureus caused no further oxidation. They remained oxidized on incubation with diphenyleneiodonium in media. Although this suggests that Prx redox cycling could be deficient in neutrophils, thioredoxin expression and thioredoxin reductase activity were similar in neutrophils and dHL-60 cells. Additionally, neutrophil thioredoxin was initially reduced and underwent oxidation after PMA activation. Thus, although the Prxs respond to oxidant generation in dHL-60 cells, in neutrophils they appear “locked” as disulfides. On this basis we propose that neutrophil Prxs are inefficient antioxidants and contribute little to peroxide removal during the oxidative burst, and speculate that they might be involved in other cell processes.

UV activation of hydrogen peroxide for removal of azithromycin antibiotic from aqueous solution: determination of optimum conditions by response surface methodology

Antibiotics have caused major concerns in environmental control due to the cumulative adverse effects on human health. This study investigates the effect of four variables: pH (3, 6, and 9), azithromycin concentration (2, 6, and 10 mg/L), hydrogen peroxide concentration (2, 6, and 10 mg/L) and contact time (30, 45, and 60 min) on azithromycin removal efficiency. The initial concentration of azithromycin is the most important and effective parameter which is inversely related to the efficiency of the treatment process. Increasing the hydrogen peroxide concentration had the least effect on the efficiency of UV/H2O2. The highest removal efficiency (76%) was at azithromycin concentration of 2 mg/L, and hydrogen peroxide concentration of 10 mg/L, 60-min contact time, and pH 3 were obtained. The lowest efficiency (38%) was obtained at pH 9, contact time of 30 min, hydrogen peroxide concentration of 2 mg/L, and azithromycin concentration of 10 mg/L. According to the results, the 2-factorial interaction fitted model was governed by the purification process. The results of this study indicate the high efficiency of UV/H2O2 process in azithromycin removal from aqueous solutions.

ITRAQ-Based Quantitative Proteomic Analysis of Chemically Induced Aquilaria sinensis Provides Insights into Agarwood Formation Mechanism.

Agarwood is a precious traditional Chinese medicine with a variety of pharmacological effects. Although efforts have been made in elucidating the mechanism of agarwood formation, little progress is obtained till now. Therefore, the molecular mechanism of agarwood formation needs to be further explored using different biological approaches. In this study, the quantitative proteomic analysis using iTRAQ technology combined with transcriptomic and metabolomic analyses on chemically induced Aquilaria sinensis is performed to elucidate the agarwood formation mechanism by formic acid stimulus. Data are available via ProteomeXchange with identifier PXD007586; 1884 proteins are detected, 504 differential proteins that show at least twofold differences in their expression levels are selected based on GO annotations, KEGG, STRING analysis, and quantitative RT-PCR analysis. The results indicate that sesquiterpene synthase, germin-like protein, pathogenesis-related protein, 6-phosphogluconate dehydrogenase, lipoyl synthase, and superoxide dismutase play important roles in the agarwood formation, suggesting that the proteins related to the plant defensive response, the removal of peroxide, the disease-resistance, the biosythesis of glycan, fatty acids, and sesquiterpene are crucial for agarwood formation.

ESTIMATION OF THE KINETIC PARAMETERS FOR H2O2 ENZYMATIC DECOMPOSITION AND FOR CATALASE DEACTIVATION

Catalase is a potentially useful biocatalyst in various industrial bioprocesses (textile industry, food processing, and pulp and paper) that require removal of hydrogen peroxide. This process can be achieved in such reactors even under isothermal conditions. However, it is usually connected with a long duration of the process or with spending a considerable amount of biocatalyst for a unit mass of the transformed substrate, which in turn leads to an increase in operating costs. They can be limited by applying the optimal temperature control, which requires the values of the thermodynamic parameters -the activation energy for reaction and the activation energy for deactivation must be known. This work reports these parameters for hydrogen peroxide decomposition and Aspergillus niger catalase deactivation at temperatures ranging from 35ºC to 50ºC.

Steering reduction and decomposition of peroxide compounds by interface interactions between MgO thin film and transition-metal support

The detection, removal and reduction of hydrogen peroxide and organic peroxides is of significant importance for its increasing application in the areas of environment, food, electrochemistry and clinical laboratory. Herein the dissociative adsorption behavior of H2O2 and organic peroxides on ultrathin magnesia (0 0 1) films deposited on transition metal is uncovered for the first time by employing periodic density-functional theory calculations with van der Waals corrections. Splitting of H2O2 on bulk MgO(0 0 1) is highly endothermic process with activation barrier 1.85 eV, indicating it is extraordinarily difficult to dissociate H2O2 on pristine MgO(0 0 1). The H2O2 is dissociated smoothly and reduced to surface hydroxyls on MgO(0 0 1)/TM, and the dissociative adsorption energies of all the considered fragmentation configurations are substantially negative, demonstrating dissociation and reduction of H2O2 is thermodynamically favorable. The mechanism of reactivity enhancement for energetically and dynamically favorable decomposition of H2O2 on supported magnesia is elucidated by characterizing the geometric structures and electronic properties. The fragmentation and reduction of diethyl peroxide and peroxyacetone are also studied to reveal the catalytic activity of ultrathin magnesia toward splitting organic peroxides. The results are wished to provide useful clue for detecting and reducing hydrogen peroxide and organic peroxides by employing oxide-metal hybrid nanostructure.

Calculated cell-specific intracellular hydrogen peroxide concentration: Relevance in cancer cell susceptibility during ascorbate therapy.

The high extracellular hydrogen peroxide (H2O2) concentrations generated during pharmacological ascorbate (P-AscH-) therapy has been shown to exhibit a high flux into susceptible cancer cells leading to a decrease in clonogenic survival. It is hypothesized that the intracellular H2O2 concentration for susceptibility is independent of cell type and that the variation observed in dosing is associated with differences in the cell-specific overall steady-state intracellular H2O2 concentration values. The steady-state variation in intracellular H2O2 concentration is coupled to a number of cellular specific transport and reaction factors including catalase activity and membrane permeability. Here a lumped-parameter mathematical modeling approach, assuming a catalase-dominant peroxide removal mechanism, is used to calculate intracellular H2O2 concentration for several cell lines. Experimental measurements of critical parameters pertaining to the model are obtained. The cell lines investigated are normal pancreatic cells, H6c7, the pancreatic cancer cell line, MIA PaCa-2 and the glioblastoma cell lines, LN-229, T98G, and U-87; all which vary in susceptibility. The intracellular H2O2 concentration estimates are correlated with the clonogenic surviving fraction for each cell line, in-vitro. The results showed that, despite the fact that the experimental parameters including catalase concentration and plasma membrane permeability demonstrated significant variability across cell lines, the calculated steady-state intracellular to extracellular H2O2 concentration ratio did not vary significantly across cell lines. Thus, the calculated intracellular H2O2 concentration is not unique in characterizing susceptibility. These results imply that, although intracellular H2O2 concentration plays a key role in cellular susceptibility to P-AscH- adjuvant therapy, its overall contribution in a unifying mechanism across cell types is complex.

Synergistic reduction of copper (II) and oxidation of norfloxacin over a novel sewage sludge-derived char-based catalyst: Performance, fate and mechanism

Abstract Nowadays, clean-up of waters with coexisting heavy metal ions and organic pollutants is of great environmental importance. In this study, a novel sewage sludge-derived char-based catalyst was firstly synthesized, and coupled with hydrogen peroxide for the simultaneous removal of copper (II) and norfloxacin in aqueous solutions. The most relevant findings revealed that zero-valent iron and zero-valent aluminum particles were successfully formed on the catalyst surface when the leaching of the sludge-derived char was reduced by the green tea extract. Nearly 100% of both copper (II) and norfloxacin were simultaneously removed due to a synergistic effect between the reduction of copper (II) and the oxidation of norfloxacin over the catalyst. The gradual addition mode of hydrogen peroxide exhibited a better performance on the simultaneous removal of copper (II) and norfloxacin. The coexisting anions like nitrate and phosphate had significant negative effects on the copper (II) removal, whereas carbonate, fluoride and phosphate had significant negative effects on the norfloxacin removal. Different copper species like zero-valent copper, copper oxide and copper hydroxide were identified in copper (II) reduction process, whereas a total of eight oxidative products were identified in norfloxacin oxidation process. A possible reaction mechanism for the simultaneous removal of copper (II) and norfloxacin by the sewage sludge-derived char-based catalyst/hydrogen peroxide system was proposed. The adsorption of both copper (II) and norfloxacin over the catalyst were firstly occurred, and then the reduction of copper (II) over both zero-valent iron and zero-valent aluminum particles on the catalyst surface as well as the Fenton oxidation of norfloxacin were followed.

105 - A Proposed DNA Binding Activity of Mitochondrial Iron-sulfur Protein Miner2

Miner2 (mitoNEET-related protein 2) is a member of a new CDGSH (Cys-Asp-Gly-Ser-His) iron-sulfur proteins family. The primary sequence analysis showed that human Miner2 has a typical mitochondrial signal peptide (residues 1-14) in its N-terminus and the mature Miner2 (113 residues) is a soluble mitochondrial matrix protein. Although Miner2 is found to be highly expressed in lung cancer, breast cancer and other types of cancer, it has not been previously purified or characterized, and very little is known on the function of Miner2 in mitochondria. Here we report that mature human Miner2 is able to bind double-stranded DNA (dsDNA), but not single-stranded DNA (ssDNA). Binding of Miner2 effectively protects the bound dsDNA from DNase I digestion. While the [2Fe-2S] clusters in Miner2 are not required for the dsDNA binding activity of Miner2, the reduced Miner2 [2Fe-2S] clusters are readily oxidized by hydrogen peroxide without disruption of the clusters, indicating that redox transition of the Miner2 [2Fe-2S] clusters may remove hydrogen peroxide in the vicinity of the Miner2-bound dsDNA. The results suggest that Miner2 may act as a DNA binding protein which protects mitochondrial DNA from oxidative damage via the redox transition of its [2Fe-2S] clusters.

131 - Inhibition of Peroxide Removal Enhances Pharmacological Ascorbate and Ionizing Radiation-Induced Cytotoxicity of Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDA) is the third leading cause of cancer deaths with a poor 5 year survival rate of only 8.2%. PDA cells produce high levels of reactive oxygen species (ROS) compared to normal cells, thereby increasing their susceptibility to oxidative stress-induced cell death. Therefore, targeting pathways that are essential in peroxide removal, such as the enzymes glutathione reductase and thioredoxin reductase, could be utilized as a tool for cancer therapy to further disrupt a cancer cells ability to overcome excess ROS. Pharmacological ascorbate is a pro-oxidant that has been shown to enhance cytotoxicity and radio-sensitize several cancer types through an H2O2-mediated mechanism. The objective of this study was to examine the effects of pharmacological ascorbate on PDA cells as an adjuvant to radiation therapy in addition to therapies that inhibit peroxide removal including auranofin (inhibits thioredoxin reductase) and 2-deoxyglucose or glucose deprivation (inhibits regeneration of NADPH). Human PDA cell lines AsPC-1 and MiaPaCa-2 were evaluated for clonogenic survival after treatment with either auranofin (500 nM), 2-deoxyglucose (25 mM), or glucose deprivation for 24 hrs, in combination with irradiation (1-2 Gy) and pharmacological ascorbate (1-2 mM) for 1 hr. Auranofin was shown to inhibit thioredoxin reductase activity, sensitize PDA cells to pharmacological ascorbate treatment and significantly reduce clonogenic cell survival by an additional 50% or 36% for MiaPaca-2 cells (P≤ 0.0001) and 29% or 39% for AsPC-1 cells (P≤ 0.01-0.0001) at 1 and 2 Gy, respectively. Inclusion of 2-deoxyglucose reduced clonogenic cell survival by an additional 20% or 9.5% for MiaPaCa-2 cells (P≤ 0.001-0.01) and 23% or 8% for AsPC-1 cells (P≤ 0.01-0.0001) at 1 and 2 Gy, respectively. Glucose deprivation enhanced cytotoxicity of MiaPaca-2 cells by an additional 40% or 29% (P≤ 0.0001) at 1 and 2 Gy, respectively. Inhibition of peroxide removal sensitizes PDA cells to irradiation and pharmacological ascorbate cytotoxicity. Therapies incorporating these strategies have the potential to be effective for the treatment of PDA.

The impact of elevated CO2 on Prochlorococcus and microbial interactions with 'helper' bacterium Alteromonas.

Prochlorococcus is a globally important marine cyanobacterium that lacks the gene catalase and relies on 'helper' bacteria such as Alteromonas to remove reactive oxygen species. Increasing atmospheric CO2 decreases the need for carbon concentrating mechanisms and photorespiration in phytoplankton, potentially altering their metabolism and microbial interactions even when carbon is not limiting growth. Here, Prochlorococcus (VOL4, MIT9312) was co-cultured with Alteromonas (strain EZ55) under ambient (400 p.p.m.) and elevated CO2 (800 p.p.m.). Under elevated CO2, Prochlorococcus had a significantly longer lag phase and greater apparent die-offs after transfers suggesting an increase in oxidative stress. Whole-transcriptome analysis of Prochlorococcus revealed decreased expression of the carbon fixation operon, including carboxysome subunits, corresponding with significantly fewer carboxysome structures observed by electron microscopy. Prochlorococcus co-culture responsive gene 1 had significantly increased expression in elevated CO2, potentially indicating a shift in the microbial interaction. Transcriptome analysis of Alteromonas in co-culture with Prochlorococcus revealed decreased expression of the catalase gene, known to be critical in relieving oxidative stress in Prochlorococcus by removing hydrogen peroxide. The decrease in catalase gene expression was corroborated by a significant ~6-fold decrease in removal rates of hydrogen peroxide from co-cultures. These data suggest Prochlorococcus may be more vulnerable to oxidative stress under elevated CO2 in part from a decrease in ecosystem services provided by heterotrophs like Alteromonas. This work highlights the importance of considering microbial interactions in the context of a changing ocean.

Planar and Cell Aggregate-Like Assemblies Consisting of Microreactors and HepG2 Cells.

The assembly of microreactors has made considerable progress toward the fabrication of artificial cells. However, their characterization remains largely limited to buffer solution-based assays in the absence of their natural role model—the biological cells. Herein, the combination of microreactors with HepG2 cells either in planar cell cultures or in the form of cell aggregates is reported. Alginate (Alg)-based microreactors loaded with catalase are assembled by droplet microfluidics, and their activity is confirmed. The acceptance of polymer-coated ∼40 μm Alg particles by proliferating HepG2 cells is depending on the terminating polymer layer. When these functional microreactors are cocultured with HepG2 cells, they can be employed for detoxification, that is, hydrogen peroxide removal, and by doing so, they assist the cells to survive. This report is among the first successful combination of microreactors with biological cells, that is, HepG2 cells, contributing to the fundamental understanding of integrating synthetic and biological partners toward the maturation of this semisynthetic concept for biomedical applications.

Redox imbalance due to the loss of mitochondrial NAD(P)-transhydrogenase markedly aggravates high fat diet-induced fatty liver disease in mice

The mechanisms by which a high fat diet (HFD) promotes non-alcoholic fatty liver disease (NAFLD) appear to involve liver mitochondrial dysfunctions and redox imbalance. We hypothesized that a HFD would increase mitochondrial reliance on NAD(P)-transhydrogenase (NNT) as the source of NADPH for antioxidant systems that counteract NAFLD development. Therefore, we studied HFD-induced liver mitochondrial dysfunctions and NAFLD in C57Unib.B6 congenic mice with (Nnt+/+) or without (Nnt-/-) NNT activity; the spontaneously mutated allele (Nnt-/-) was inherited from the C57BL/6J mouse substrain. After 20 weeks on a HFD, Nnt-/- mice exhibited a higher prevalence of steatohepatitis and content of liver triglycerides compared to Nnt+/+ mice on an identical diet. Under a HFD, the aggravated NAFLD phenotype in the Nnt-/- mice was accompanied by an increased H2O2 release rate from mitochondria, decreased aconitase activity (a redox-sensitive mitochondrial enzyme) and higher susceptibility to Ca2+-induced mitochondrial permeability transition. In addition, HFD led to the phosphorylation (inhibition) of pyruvate dehydrogenase (PDH) and markedly reduced the ability of liver mitochondria to remove peroxide in Nnt-/- mice. Bypass or pharmacological reactivation of PDH by dichloroacetate restored the peroxide removal capability of mitochondria from Nnt-/- mice on a HFD. Noteworthy, compared to mice that were chow-fed, the HFD did not impair peroxide removal nor elicit redox imbalance in mitochondria from Nnt+/+ mice. Therefore, HFD interacted with Nnt mutation to generate PDH inhibition and further suppression of peroxide removal. We conclude that NNT plays a critical role in counteracting mitochondrial redox imbalance, PDH inhibition and advancement of NAFLD in mice fed a HFD. The present study provide seminal experimental evidence that redox imbalance in liver mitochondria potentiates the progression from simple steatosis to steatohepatitis following a HFD.

Acute hydrogen peroxide (H2O2) exposure does not cause oxidative stress in late-copepodite stage of Calanus finmarchicus

ABSTRACTUse of hydrogen peroxide (H2O2) for removal of salmon lice in the aquaculture industry has created concern that non-target organisms might be affected during treatment scenarios. The aim of the present study was to examine the potential for H2O2 to produce oxidative stress and reduce survival in one of the most abundant zooplankton species in Norwegian coastal areas, the copepod Calanus finmarchicus. Copepods were subjected to two 96-hr tests: (1) acute toxicity test where mortality was determined and (2) treated copepods were exposed to concentrations below the No Observed Effect Concentration (0.75 mg/L) H2O2 and analyzed for antioxidant enzyme activities, as well as levels of glutathione (GSH) and malondialdehyde (MDA). Compared to available and comparable LC50 values from the literature, our results suggest that C. finmarchicus is highly sensitive to H2O2. However, 96-hr exposure of C. finmarchicus to 0.75 mg H2O2/L did not significantly affect the antioxidant systems even though the concentration is just below the level where mortality is expected. Data suggest that aqueous H2O2 exposure did not cause cellular accumulation with associated oxidative stress, but rather produced acute effects on copepod surface (carapace). Further investigation is required to ensure that aqueous exposure during H2O2 treatment in salmon fish farms does not exert adverse effects on local non-target crustacean species and populations. In particular, studies on copepod developmental stages with a more permeable carapace are warranted.

Effect of Methotrexate and Omega-3 Combination on Cytogenetic Changes of Bone Marrow and Some Enzymatic Antioxidants: An Experimental Study

Effect of Methotrexate and Omega-3 Combination on Cytogenetic Changes of Bone Marrow and Some Enzymatic Antioxidants: An Experimental Study

Effect of Methotrexate and Omega-3 Combination on Cytogenetic Changes of Bone Marrow and Some Enzymatic Antioxidants: An Experimental Study

Effect of Methotrexate and Omega-3 Combination on Cytogenetic Changes of Bone Marrow and Some Enzymatic Antioxidants: An Experimental Study

Methylglyoxal-Induced Protection Response and Toxicity: Role of Glutathione Reductase and Thioredoxin Systems.

Thioredoxin (Trx) and glyoxalase (Glo) systems have been suggested to be molecular targets of methylglyoxal (MGO). This highly reactive endogenous compound has been associated with the development of neurodegenerative pathologies and cell death. In the present study, the glutathione (GSH), Trx, and Glo systems were investigated to understand early events (0.5-3h) that may determine cell fate. It is shown for the first time that MGO treatment induces an increase in glutathione reductase (GR) protein in hippocampal slices (1h) and HT22 nerve cells (0.5 and 2.5h). Thioredoxin interacting protein (Txnip), thioredoxin reductase (TrxR), Glo1, and Glo2 were markedly increased (2- to 4-fold) in hippocampal slices and 1.2- to 1.3-fold in HT22 cells. This increase in protein levels in hippocampal slices was followed by a corresponding increase in GR, TrxR, and Glo1 activities, but not in HT22 cells. In these cells, GR and TrxR activities were decreased by MGO. This result is in agreement with the idea that MGO can affect the Trx/TrxR reducing system, and now we show that GR and Txnip can also be affected by MGO. Impairment in the GR or TrxR reducing capacity can impair peroxide removal by glutathione peroxidase and peroxiredoxin, as both peroxidases depend on reduced GSH and Trx, respectively. In this regard, inhibition of GR and TrxR by 2-AAPA or auranofin, respectively, potentiated MGO toxicity in differentiated SH-SY5Y cells. Overall, MGO not only triggers a clear defense response in hippocampal slices and HT22 cells but also impairs the Trx/TrxR and GSH/GR reducing couples in HT22 cells. The increased MGO toxicity caused by inhibition of GR and TrxR with specific inhibitors, or their inhibition by MGO treatment, supports the notion that both reducing systems are relevant molecular targets of MGO.

АЛЕЛЬНИЙ ПОЛІМОРФІЗМ ГЕНІВ GSTS У МАТЕРІВ ІЗ ПЛАЦЕНТАРНОЮ ДИСФУНКЦІЄЮ ТА ЇХ НОВОНАРОДЖЕНИХ: АКУШЕРСЬКІ ТА ПЕРИНАТАЛЬНІ НАСЛІДКИ

Роль плаценти зумовлена реалізацією ряду функціональних механізмів забезпечення росту і внутрішньоутробного розвитку плода. Глутатіон-S-трансферази беруть активну участь у знешкодженні продуктів пероксидного окиснення ліпідів та пероксидів ДНК, відновлюючи органічні гідроперекиси в спирти та сприяючи ізомеризації деяких стероїдів та простагландинів. При наявності певних поліморфних варіантів GSTT1, GSTM1, GSTP1 генів сімейства глутатіон-S-трансфераз проходить виснаження глутатіонзалежного АОЗ та пригнічення детоксикаційної функції плаценти.Мета дослідження – визначити алельний поліморфізм генів глутатіон-S-трансфераз GSTT1 та GSTM1 у жінок із плацентарною дисфункцією, в здорових новонароджених та новонароджених із затримкою внутрішньоутробного розвитку на основе проведеного молекулярно-генетичного дослідження пуповинної крові.Матеріли і методи. У дослідження було залучено 105 жінок: основну групу склали 33 жінки з плацетарною дисфункцією (ПД) без затримки внутрішньоутробного розвитку (ЗВУР) у дітей, яких вони народили (перша група), та 17 жінок із ПД та ЗВУР (друга група). Контрольну групу склали 55 жінок (третя група), які народили здорових доношених дітей.Результати досліджень та їх обговорення. Встановлено, що ризик розвитку ПД та ПД зі ЗВУР за домінантної моделі успадкування (313AG + 313GG порівняно з 313AA) достовірно зростав. Перспективними прогностичними моделями міжгенної взаємодії для оцінки розвитку ПД передбачається аналіз варіантів генів GSTM1, GSTP1, а ПД зі ЗВУР – GSTT1, GSTM1, GSTP1. У результаті аналізу проб сироватки пуповинної крові та отриманих даних встановлено, що частота поліморфного варіанта GSTМ1“+” у всіх новонароджених області склала 42,69 %, а GSTМ1 “–” – 57,30 %. Частота поліморфного варіанта GSTT1“+” у всіх новонароджених області становила 79,77 %, а GSTT1 “–” – 20,22 %.Висновки. Результати досліджень розподілу різних алельних варіантів генів GSTM1 і GSTT1 показали їх відмінності у різних групах новонароджених. Виявлено вірогідну різницю між частотами делеційного варіанта гена GSTM1 у здорових новонароджених та новонароджених із ЗВУР. Сукупний аналіз комбінованого впливу декількох чинників виявив, що перебіг вагітності у жінок із ПД, гестозом та генотипом GSTМ1deletion асоціюється із значним зростанням ризику ЗВУР у плодів.

Redox environment in stem and differentiated cells: A quantitative approach

Stem cells are believed to maintain a specific intracellular redox status through a combination of enhanced removal capacity and limited production of ROS. In the present study, we challenge this assumption by developing a quantitative approach for the analysis of the pro- and antioxidant ability of human embryonic stem cells in comparison with their differentiated descendants, as well as adult stem and non-stem cells. Our measurements showed that embryonic stem cells are characterized by low ROS level, low rate of extracellular hydrogen peroxide removal and low threshold for peroxide-induced cytotoxicity. However, biochemical normalization of these parameters to cell volume/protein leads to matching of normalized values in stem and differentiated cells and shows that tested in the present study cells (human embryonic stem cells and their fibroblast-like progenies, adult mesenchymal stem cells, lymphocytes, HeLa) maintain similar intracellular redox status. Based on these observations, we propose to use ROS concentration averaged over the cell volume instead of ROS level as a measure of intracellular redox balance. We show that attempts to use ROS level for comparative analysis of redox status of morphologically different cells could lead to false conclusions. Methods for the assessment of ROS concentration based on flow cytometry analysis with the use of H2DCFDA dye and HyPer, genetically encoded probe for hydrogen peroxide, are discussed.

Cloning, expression and antioxidant activity of a thioredoxin peroxidase from Branchiostoma belcheri tsingtaunese.

Peroxiredoxins (Prxs) are ubiquitous antioxidant enzymes that catalyze the thioredoxin- dependent reduction of hydroperoxides. In this study, a novel thioredoxin peroxidase (Bbt-TPx1), a member of the peroxiredoxin superfamily, was found by EST sequence analysis of a cDNA library of Branchiostoma belcheri tsingtaunese ovary. The sequence of a full-length cDNA clone contained an open reading frame encoding a polypeptide of 198 amino acid residues, with a calculated molecular weight of 22,150 Da. The expression patterns of the protein at different developmental stages and adult amphioxus tissues indicate that this enzyme may play important roles in anti-oxidation and innate immunity. The recombinant Bbt-TPx1 protein was expressed with a polyhistidine-tag in Escherichia coli and purified using Ni chromatography followed by SP cation exchange chromatography. The rBbt-TPx1 protein existed as a dimer under non-reducing conditions, and was dissociated into monomers by dithiothreitol (DTT); it might predominantly exist in oligomeric form. The rBbt-TPx1 protein showed a significant thiol-dependent peroxidase activity, removing hydrogen peroxide in the presence of dithiothreitol (DTT), but not glutathione (GSH). Protection of plasmid DNA and the thiol-protein from damage by metal-catalyzed oxidation (MCO) in vitro was also revealed.