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Registros recuperados: 36
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A method for multiple sequential analyses of macrophage functions using a small single cell sample BJMBR
Nascimento,F.R.F.; Rodríguez,D.; Gomes,E.; Fernvik,E.C.; Russo,M..
Microbial pathogens such as bacillus Calmette-Guérin (BCG) induce the activation of macrophages. Activated macrophages can be characterized by the increased production of reactive oxygen and nitrogen metabolites, generated via NADPH oxidase and inducible nitric oxide synthase, respectively, and by the increased expression of major histocompatibility complex class II molecules (MHC II). Multiple microassays have been developed to measure these parameters. Usually each assay requires 2-5 x 10(5) cells per well. In some experimental conditions the number of cells is the limiting factor for the phenotypic characterization of macrophages. Here we describe a method whereby this limitation can be circumvented. Using a single 96-well microassay and a very small...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Macrophages; Nitric oxide; Hydrogen peroxide; MHC II; Method.
Ano: 2003 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2003000900012
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Age-related changes and effects of regular low-intensity exercise on gait, balance, and oxidative biomarkers in the spinal cord of Wistar rats BJMBR
Silveira,E.M.S.; Kroth,A.; Santos,M.C.Q.; Silva,T.C.B.; Silveira,D.; Riffel,A.P.K.; Scheid,T.; Trapp,M.; Partata,W.A..
The present study aimed to analyze age-related changes to motor coordination, balance, spinal cord oxidative biomarkers in 3-, 6-, 18-, 24-, and 30-month-old rats. The effects of low-intensity exercise on these parameters were also analyzed in 6-, 18-, and 24-month-old rats. Body weight, blood glucose, total cholesterol, and high-density lipoprotein (HDL) cholesterol were assessed for all rats. The soleus muscle weight/body weight ratio was used to estimate skeletal muscle mass loss. Body weight increased until 24 months; only 30-month-old rats exhibited decreased blood glucose and increased total cholesterol and HDL cholesterol. The soleus muscle weight/body weight ratio increased until 18 months, followed by a small decrease in old rats. Exercise did not...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Superoxide anion generation; Hydrogen peroxide; Total thiol content; Lipid hydroperoxide levels; Total antioxidant capacity; Superoxide dismutase.
Ano: 2019 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2019000700608
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Análise de processos alternativos na preparação de esqueletos para uso didático - DOI: 10.4025/actascibiolsci.v30i4.5876 Biological Sciences
Silveira, Márcio José da; UEM; Teixeira, Gustavo Monteiro; UNESP/Botucatu; Oliveira, Edson Fontes de; UEM.
Laboratórios de Zoologia em Instituições de Pesquisa e Ensino têm demonstrado grande demanda por peças anatômicas para utilização em aulas práticas. No entanto, embora a bibliografia voltada para este tema não seja escassa, são raras as análises das relações custo/benefício de tais processos levando em consideração aspectos técnicos, como tempo de preparo, qualidade das peças e recursos materiais e humanos. Além de técnicas usualmente utilizadas, novos produtos de baixo custo, não-citados na literatura e encontrados facilmente no mercado, também foram testados. O principal objetivo deste trabalho foi a elaboração e organização de informações sobre técnicas alternativas de maceração de peças ósseas para coleções didáticas, realizando análises comparativas...
Palavras-chave: Maceração; Clarificação de esqueletos; Peróxido de hidrogênio; Suco de mamão maceration; Skeleton clarification; Hydrogen peroxide; Papaya juice.
Ano: 2008 URL: http://periodicos.uem.br/ojs/index.php/ActaSciBiolSci/article/view/5876
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Antioxidant responses of Laeonereis acuta (Polychaeta) after exposure to hydrogen peroxide BJMBR
Rosa,C.E. da; Bianchini,A.; Monserrat,J.M..
The effects of H2O2 were evaluated in the estuarine worm Laeonereis acuta (Polychaeta, Nereididae) collected at the Patos Lagoon estuary (Southern Brazil) and maintained in the laboratory under controlled salinity (10 psu diluted seawater) and temperature (20°C). The worms were exposed to H2O2 (10 and 50 µM) for 4, 7, and 10 days and the following variables were determined: oxygen consumption, catalase (CAT) and glutathione peroxidase activity in both the supernatant and pellet fractions of whole body homogenates. The concentrations of non-protein sulfhydryl and lipid peroxides (LPO) were also measured. The oxygen consumption response was biphasic, decreasing after 4 days and increasing after 7 and 10 days of exposure to 50 µM H2O2 (P < 0.05). At the...
Tipo: Info:eu-repo/semantics/other Palavras-chave: Worms; Laeonereis acuta; Hydrogen peroxide; Oxidative stress; Antioxidant enzymes; Oxygen consumption.
Ano: 2008 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2008000200007
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Characterization of native and oxidized starches of two varieties of Peruvian carrot (Arracacia xanthorrhiza, B.) from two production areas of Paraná state, Brazil BABT
Matsuguma,Luciana Shizue; Lacerda,Luiz Gustavo; Schnitzler,Egon; Carvalho Filho,Marco Aurélio da Silva; Franco,Célia Maria Landi; Demiate,Ivo Mottin.
Two commercial varieties of Peruvian carrot ('Amarela de Carandaí' and 'Senador Amaral') were processed into flour, starch and bagasse and chemically evaluated. The starch was extracted, modified with H2O2 and characterized by the physicochemical methods. By using the methylene blue dyeing, the granules of the modified starches showed intense blue color. The carboxyl content, the reducing power and the amount of the water liberated from the pastes after the freeze-thawing were higher for the oxidized starches and their pastes were clearer than those of the native starches of the two varieties from the two production areas. The RVA viscoamylography showed that the modified starches had lower viscosities with differences between the varieties. In the thermal...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Peruvian carrot varieties; Starch; Hydrogen peroxide; Technological properties.
Ano: 2009 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132009000300022
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Cytotoxic activity of BCG-activated macrophages against L929 tumor cells is nitric oxide-dependent BJMBR
Nascimento,F.R.F.; Ribeiro-Dias,F.; Russo,M..
The tumoricidal activity of activated macrophages has been attributed largely to the release of tumor necrosis factor (TNF), or to the production of reactive oxygen or nitrogen intermediates. The L929 tumor cell line (a murine fibroblast-like cell) when treated with actinomycin D (ActD) has been used to measure TNF<FONT FACE="Symbol">a</FONT> cytotoxicity. In the present study, we determined the cytotoxic activity of BCG-activated peritoneal macrophages against ActD-untreated L929 tumor cells. Furthermore, we measured the production of hydrogen peroxide (H2O2), nitric oxide (NO) and TNF by macrophages cultured in the presence or absence of L929 cells. As expected, BCG-activated macrophages produced significant amounts of H2O2 (16.0 ± 3.0 µM),...
Tipo: Info:eu-repo/semantics/other Palavras-chave: Cytotoxicity; Macrophages; L929 tumor cells; Nitric oxide; TNF; Hydrogen peroxide.
Ano: 1998 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1998001200012
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Cytotoxicity of chlorhexidine digluconate to murine macrophages and its effect on hydrogen peroxide and nitric oxide induction BJMBR
Bonacorsi,C.; Raddi,M.S.G.; Carlos,I.Z..
Chlorhexidine, even at low concentrations, is toxic for a variety of eukaryotic cells; however, its effects on host immune cells are not well known. We evaluated in vitro chlorhexidine-induced cytotoxicity and its effects on reactive oxygen/nitrogen intermediate induction by murine peritoneal macrophages. Thioglycollate-induced cells were obtained from Swiss mice by peritoneal lavage with 5 ml of 10 mM phosphate-buffered saline, washed twice and resuspended (10(6) cells/ml) in appropriate medium for each test. Cell preparations contained more than 95% macrophages. The cytotoxicity was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assay and the presence of hydrogen peroxide (H2O2) and nitric oxide (NO) by the horseradish...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Chlorhexidine; Cytotoxicity; Macrophages; Nitric oxide; Hydrogen peroxide.
Ano: 2004 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2004000200007
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Development of a comet-FISH assay for the detection of DNA damage in hemocytes of Crassostrea gigas ArchiMer
Perez Garcia, Maria Concepcion; Rouxel, Julien; Akcha, Farida.
In this work, the DNA-damaging effect of hydrogen peroxide on the structural integrity of nucleolar organizer regions (NORs) was studied for the first time by comet-FISH in the Pacific oyster Crassostrea gigas. Global DNA damage was assessed in hemocytes using an alkaline version of the comet assay. Next, NOR sensitivity was analysed by mapping major rDNA repeat unit by fluorescence in situ hybridisation (FISH) on the same comet slides. Exposure of hemocytes to 100 μM of hydrogen peroxide induced a significant increase in both DNA damage and number of FISH-signals of major ribosomal genes versus the control. Moreover, a significant positive correlation was shown between DNA damage as measured by the comet assay (percentage of DNA in comet tail) and the...
Tipo: Text Palavras-chave: Crassostrea gigas; Hydrogen peroxide; Comet assay; Comet-FISH; Genotoxicity.
Ano: 2015 URL: https://archimer.ifremer.fr/doc/00250/36157/34712.pdf
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Efeito do etanol e do peróxido de hidrogênio intragástrico sobre a mucosa gástrica de rã (Rana catesbeiana, SHAW) BABT
Estivallet,Hidê Virgínia; Rodrigues,Maria Inês; Marroni,Norma Possa.
This work investigated the frog gastric mucosa response to hydrogen peroxide and ethanol induced injury. Acid and mucus secretion were estimated "in vitro" in control animals with intragastric absolute ethanol (1ml/30min. or 2ml/60min.) and hydrogen peroxide. The gastric mucosa morphological conditions were assessed "in vivo", concerning lesion area, pH and mucus. Ethanol (1ml/30min.) was observed to cause hyperemia, cell damage, rupture, edema, erosions, necrosis in gastric mucosa and significant increase in acid secretion. Absolute ethanol (2ml/60min.) caused a decrease in acid secretion due to alcalinization and an increase of mucus and pH. Intragastric hydrogem peroxide provoked gastric unwrinkling and hyperemia, acid secretions were not increased,...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Gastric acid secretion; Mucus; Ethanol; Hydrogen peroxide; Frog.
Ano: 1998 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89131998000100007
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Effect of trolox C on cardiac contracture induced by hydrogen peroxide BJMBR
Belló-Klein,A.; Oliveira,A.R.; Miranda,M.F.S.; Irigoyen,M.C.; Homem-de-Bittencourt Jr.,P.I.; Llesuy,S.; Belló,A.A..
Hydrogen peroxide (H2O2) perfused into the aorta of the isolated rat heart induces a positive inotropic effect, with cardiac arrhythmia such as extrasystolic potentiation or cardiac contractures, depending on the dose. The last effect is similar to the "stone heart" observed in reperfusion injury and may be ascribed to lipoperoxidation (LPO) of the membrane lipids, to protein damage, to reduction of the ATP level, to enzymatic alterations and to cardioactive compounds liberated by LPO. These effects may result in calcium overload of the cardiac fibers and contracture ("stone heart"). Hearts from male Wistar rats (300-350 g) were perfused at 31oC with Tyrode, 0.2 mM trolox C, 256 mM H2O2 or trolox C + H2O2. Cardiac contractures (baseline elevation of the...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Trolox C; "stone heart"; Free radicals; Hydrogen peroxide.
Ano: 1997 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1997001100013
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Effects of H2O2, Fe2+ and Fe3+ on curcumin-induced chromosomal aberrations in CHO cells Genet. Mol. Biol.
Antunes,Lusânia Maria Greggi; Araújo,Maria Cristina Paiva; Dias,Francisca da Luz; Takahashi,Catarina Satie.
The effects of H2O2, Fe2+ and Fe3+ on curcumin-induced clastogenicity were evaluated in CHO cells. Curcumin combined with H2O2 did not increase the chromosomal aberrations more than expected based on a simple additive effect. In contrast, the combination of curcumin-Fe significantly decreased the total number of chromosomal aberrations and the number of abnormal metaphases. The clastogenicity of curcumin may be related to its pro-oxidant properties and its ability to generate free radicals.
Tipo: Info:eu-repo/semantics/article Palavras-chave: CHO; Chromosomal aberrations; Curcumin; Hydrogen peroxide; Mutagenesis.
Ano: 2005 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572005000100028
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Effects of hydrogen peroxide mouthwash on preventing ventilator-associated pneumonia in patients admitted to the intensive care unit BJID
Nobahar,Monir; Razavi,Mohammad Reza; Malek,Farhad; Ghorbani,Raheb.
Abstract Aims The aim of the study was to determine the effect of hydrogen peroxide (HP) mouthwash on the incidence of ventilator associated pneumonia (VAP) in patients admitted to the intensive care unit (ICU). Methods This was a randomized clinical trial conducted on 68 patients. The intervention group used 3% HP as mouthwash and the control group used mouthwashes with 0.9% normal saline (NS) twice a day. Data were collected using a questionnaire and the Modified Clinical Pulmonary Infection Score (MCPIS). MCPIS includes five items, body temperature: white blood cell count, pulmonary secretions, the ratio of pressure of arterial oxygen (PaO2) to fraction of inspired oxygen (FiO2), and the chest X-ray. Each of these items scored 0–2. Scores ≥6 were...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Nosocomial infection; Ventilator associated pneumonia; Hydrogen peroxide; Intensive care unit.
Ano: 2016 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-86702016000500444
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Evaluation of pregerminative treatments in gulupa seeds (P. edulis f. edulis Sims). Rev. Bras. Frutic.
Camargo,María Antonia Martínez; Coronado,Ana Cruz Morillo; Mora,Edilberto Cepeda; Fernández,Sandra Yaneth Mesa.
Abstract The genus Passiflora, commonly known as fruits of passion, includes numerous species, including gulupa (Passiflora edulis f. edulis), of nutracetic and economic importance, both for consumption in nature and for its agro-industrial applicability. This research was developed to evaluate the effects of various pre-germinative treatments on the germination of gulupa seeds from the municipality of Ramiriquí (Boyacá), such as: exposure to hydrogen peroxide (H2O2), hypochlorite of sodium (NaOCl), gibberellic acid (GA3), distilled water imbibition and stratification at 4 °C, in varying concentrations and exposure times (24 and 48 hours), using an experimental design completely random, with three repetitions of 50 seed each one. Statistical analysis...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Passiflora; Gulupa; Germination; Hydrogen peroxide; Gibberellic acid; Sodium hypochlorite.
Ano: 2020 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-29452020000302003
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Experimental study on the performance of microwave assisted Hydrogen peroxide (H2O2) pretreatment of rice straw CIGR Journal
Singh, Renu; Tiwari, Sapna; Srivastava, Monika; Shukla, Ashish.
Biofuels are essentials as they can provide impending substitute for fossil fuels.  Rice straw has gained much attention from researchers because of its usability as a potential feedstock for bioethanol production.  Pre-treatments are crucial for enzymatic hydrolysis of rice straw.  In this study, combination of microwave and hydrogen peroxide (H2O2) is employed for the delignification of rice straw.  The Response surface methodology is used to optimize the pretreatment conditions with respect to H2O2 concentration, microwave power and irradiation time.  Under optimum conditions, maximum reducing sugar obtained through microwave assisted H2O2 is 1,453.64 µg/mL.  The chemical and morphological analysis ascertained that the surface of the samples treated...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Biofuel; Bio-ethanol Biomass Enzymatic hydrolysis; Rice straw; Biofuel; Microwave; Hydrogen peroxide.
Ano: 2014 URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/2633
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Gastrodin induced HO-1 and Nrf2 up-regulation to alleviate H2O2-induced oxidative stress in mouse liver sinusoidal endothelial cells through p38 MAPK phosphorylation BJMBR
Zhang,Hongbin; Yuan,Bo; Huang,Hanfei; Qu,Siming; Yang,Shikun; Zeng,Zhong.
Nuclear factor erythroid-related factor 2 (Nrf2) has been implicated in several detoxifying and antioxidant defense processes. Nrf2-mediated heme oxygenase-1 (HO-1) expression was demonstrated to play a key role against oxidative stress. Gastrodin (GSTD) is a well-known active compound isolated from the roots of Rhizoma gastrodiae, a plant used in ancient Chinese traditional medicine. The aim of this work was to investigate whether GSTD could alleviate H2O2-induced oxidative stress in mouse liver sinusoidal endothelial cells (LSECs). In LSECs exposed to 1 mM H2O2, treatment with GSTD (1, 10, or 50 µM) resulted in higher cell viability than the untreated control. Treated cells maintained a higher Bcl2/Bax ratio and suppressed caspase-9 expression compared...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Gastrodin; Liver sinusoidal endothelial cells; Heme oxygenase 1; Oxidative stress; Hydrogen peroxide.
Ano: 2018 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2018001000611
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Glutathione peroxidase induction protects Saccharomyces cerevisiae sod1deltasod2delta double mutants against oxidative damage BJMBR
Manfredini,V.; Roehrs,R.; Peralba,M.C.R.; Henriques,J.A.P.; Saffi,J.; Ramos,A.L.L.P.; Benfato,M.S..
Saccharomyces cerevisiae mutants deficient in superoxide dismutase genes (sod1delta, sod2delta and the double mutant) were subjected to H2O2 stress in the stationary phase. The highest sensitivity was observed in the sod2delta mutant, while the sod1deltasod2delta double mutant was not sensitive. Sod mutants had lower catalase activity (44%) than wild-type cells, independent of H2O2 stress. Untreated cells of sod1deltasod2delta double mutants showed increased glutathione peroxidase activity (126%), while sod1delta had lower activity (77%) than the wild type. Glutathione levels in sod1delta were increased (200-260%) after exposure to various H2O2 concentrations. In addition, the highest malondialdehyde levels could be observed without H2O2 treatment in...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Catalase; Superoxide dismutase; Glutathione; Hydrogen peroxide; Saccharomyces cerevisiae; Reactive oxygen species.
Ano: 2004 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2004000200001
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Heterologous expression of a rice metallothionein isoform (OsMTI-1b) in Saccharomyces cerevisiae enhances cadmium, hydrogen peroxide and ethanol tolerance BJM
Ansarypour,Zahra; Shahpiri,Azar.
Abstract Metallothioneins are a superfamily of low-molecular-weight, cysteine (Cys)-rich proteins that are believed to play important roles in protection against metal toxicity and oxidative stress. The main purpose of this study was to investigate the effect of heterologous expression of a rice metallothionein isoform (OsMTI-1b) on the tolerance of Saccharomyces cerevisiae to Cd2+, H2O2 and ethanol stress. The gene encoding OsMTI-1b was cloned into p426GPD as a yeast expression vector. The new construct was transformed to competent cells of S. cerevisiae. After verification of heterologous expression of OsMTI-1b, the new strain and control were grown under stress conditions. In comparison to control strain, the transformed S. cerevisiae cells expressing...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Cadmium; Ethanol; Hydrogen peroxide; Rice metallothionein; S. cerevisiae.
Ano: 2017 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822017000300537
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High levels of catalase in sod mutants of Saccharomyces cerevisiae in high aeration conditions BJM
Martins,Vanessa; Manfredini,Vanusa; Benfato,Mara Silveira.
Saccharomyces cerevisiae mutants deficient in superoxide dismutase genes (sod1delta, sod2delta and sod1deltasod2delta mutants) in a stationary phase of growth under high aeration conditions were subjected to H2O2 stress. All the mutants were sensitive after H2O2 treatment. Glutathione peroxidase levels were significantly lower in sod1delta and sod2delta single mutants than in the wild-type without treatment. After exposure to H2O2 concentrations, glutathione peroxidase levels were increased in sod1deltasod2delta double mutants and the sod2delta single mutant, while sod1delta maintained lower gluthatione peroxidase activities. The sod2delta mutant demonstrated a similar catalase activity to that of the wild-type without treatment, whilst decreased catalase...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Catalase; Superoxide dismutase; High aeration; Hydrogen peroxide; S. cerevisiae.
Ano: 2005 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822005000400008
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Hydrogen Peroxide Induced Oxidative Damage on Mineral Density and Mechanical Properties of Bone BABT
Cicek,Ekrem; Cakmak,Enes.
ABSTRACT Hydrogen peroxide is a common reactive oxygen species involved in the catalytic mechanism though it is toxic to cells due to its oxidative nature. This work investigates the effects of hydrogen peroxide induced oxidative damage on bone mineral density and mechanical properties of bone which is primarily a composite material composed primarily of collagen fibers and biominerals. Sheep leg bones were exposed to hydrogen peroxide for a week. Bone mineral density was measured by using dual energy X-ray absorptiometry. Compressive modulus tests were applied to bone in order to determine mechanical properties. Our study shows that the hydrogen peroxide induced oxidative stress has negative effects on bone mineral density and stiffness. We observed...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Bone mineral density; Compressive modulus; Hydrogen peroxide; Reactive oxygen species.
Ano: 2018 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132018000100320
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Hydrogen peroxide induces a specific DNA base change profile in the presence of the iron chelator 2,2’ dipyridyl in Escherichia coli BJMBR
Felício,D.L.; Almeida,C.E.B.; Silva,A.B.; Leitão,A.C..
Pretreatment of Escherichia coli cultures with the iron chelator 2,2’-dipyridyl (1 mM) protects against the lethal effects of low concentrations of hydrogen peroxide (<15 mM). However, at H2O2 concentrations equal to or greater than 15 mM, dipyridyl pretreatment increases lethality and mutagenesis, which is attributed to the formation of different types of DNA lesions. We show here that pretreatment with dipyridyl (1 mM) prior to challenge with high H2O2 concentrations (≥15 mM) induced mainly G:C→A:T transitions (more than 100X with 15 mM and more than 250X with 20 mM over the spontaneous mutagenesis rate) in E. coli. In contrast, high H2O2 concentrations in the absence of dipyridyl preferentially induced A:T→T:A transversions (more than 1800X and more...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Hydrogen peroxide; Dipyridyl; Mutagenesis; Iron; Fenton reaction.
Ano: 2009 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2009001100003
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