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1.
Chem Commun (Camb) ; 55(72): 10740-10743, 2019 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-31432813

RESUMO

We constructed a two-photon fluorescence ratio probe (CST) for in situ quantitative real-time detection of mitochondrial O2˙-. Fluorescence imaging showed that O2˙- was over-generated from mitochondria and conveyed to the cytoplasm via voltage-dependent anion channels in hepatic ischemia-reperfusion mice, damaging the important functional protein aconitase in the cytoplasm.


Assuntos
Fígado/metabolismo , Mitocôndrias/química , Imagem Óptica , Fótons , Traumatismo por Reperfusão/metabolismo , Superóxidos/química , Animais , Ânions/química , Ânions/metabolismo , Transporte Biológico , Corantes Fluorescentes/química , Camundongos , Mitocôndrias/metabolismo , Estrutura Molecular , Superóxidos/metabolismo
2.
Food Chem ; 298: 125093, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31260960

RESUMO

The purpose of this study was to investigate the impact of ozonation process on the level of oxidative stress markers in raspberries stored at room temperature. Raspberry fruit was ozonated with an ozone concentration of 8-10 ppm for 30 min, every 12 h, for 72 h of storage at room temperature. Research showed that ozonated raspberries were characterized by higher activity of superoxide dismutase, ascorbate peroxidase and phenylalanine ammonia-lyase. In turn, the ability to generate superoxide anion radical and hydrogen peroxide by ozone-treated fruit was significantly lower than in the control sample due to higher activities of ROS detoxification systems.


Assuntos
Armazenamento de Alimentos/métodos , Frutas/metabolismo , Estresse Oxidativo , Ozônio/química , Rubus/metabolismo , Antioxidantes/química , Antioxidantes/metabolismo , Ascorbato Peroxidases/metabolismo , Biomarcadores/química , Biomarcadores/metabolismo , Frutas/química , Peróxido de Hidrogênio/química , Peróxido de Hidrogênio/metabolismo , Fenilalanina Amônia-Liase/metabolismo , Espécies Reativas de Oxigênio/química , Espécies Reativas de Oxigênio/metabolismo , Rubus/química , Superóxido Dismutase/metabolismo , Superóxidos/química , Superóxidos/metabolismo , Temperatura Ambiente
3.
Pestic Biochem Physiol ; 157: 45-52, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31153476

RESUMO

Herein, we describe the enhanced antifungal activity of silver nanoparticles biosynthesized by cell free filtrate of Trichoderma viride (MTCC 5661) in comparison to chemically synthesized silver nanoparticles (CSNP) of similar shape and size. Biosynthesized silver nanoparticles (BSNP) enhanced the reduction in dry weight by 20 and 48.8% of fungal pathogens Fusarium oxysporum and Alternaria brassicicola respectively in comparison to their chemical counterparts (CSNP). Nitroblue tetrazolium and Propidium iodide staining demonstrated the higher generation of superoxide radicals lead to higher death in BSNP treated fungus in comparison to CSNP. Scanning electron microscopy of A. brassicicola revealed the osmotic imbalance and membrane disintegrity to be major cause for fungal cell death after treatment with BSNP. To gain an insight into the mechanistic aspect of enhanced fungal cell death after treatment of BSNP in comparison to CSNP, stress responses and real time PCR analysis was carried out with A. brassicicola. It revealed that generation of ROS, downregulation of antioxidant machinery and oxidative enzymes, disruption of osmotic balance and cellular integrity, and loss of virulence are the mechanisms employed by BSNP which establishes them as superior antifungal agent than their chemical counterparts. With increasing drug resistance and ubiquitous presence of fungal pathogens in plant kingdom, BSNP bears the candidature for new generation of antifungal agent.


Assuntos
Antifúngicos/química , Antifúngicos/farmacologia , Nanopartículas Metálicas/química , Doenças das Plantas/microbiologia , Prata/química , Alternaria/efeitos dos fármacos , Fusarium/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Oxirredução/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Superóxidos/metabolismo
4.
Environ Sci Pollut Res Int ; 26(22): 22625-22640, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31168715

RESUMO

Endogeic earthworm Metaphire posthuma (Valliant, 1868) is a common biological component of the tropical soil of India and other countries. The species is reported to influence fertility and porosity of soil and bear a high composting potential. Intensive agricultural, industrial, and mining activities increase the amount of toxic metals in soil causing physiological adversity in earthworm and other biotic components in soil. Coelomocytes, the chief immunoeffector cells of earthworm, perform diverse physiological functions under the challenge of toxins and pathogens. The experimental earthworms collected separately from soils with agricultural and tannery activities were subjected to quantitation of prooxidation and antioxidation parameters for estimation of oxidative stress. Total count, cellular aggregation, generation of reactive oxygen species (ROS), superoxide anion, nitric oxide, activities of phenoloxidase, superoxide dismutase, catalase and glutathione-s-transferase, and amount of total protein were estimated in the coelomocytes of M. posthuma as experimental end points of toxicity screening. Concentrations of cadmium, chromium, lead, and mercury were determined in the soil samples to assess the degree of toxic contamination. The increase in the amount of prooxidants and decrease in the activities of antioxidant enzymes indicated the signs of oxidative stress in the coelomocytes of the organism. Aggregation of circulating coelomocytes is considered as an immune response involved in pathogen encapsulation response as reported in many invertebrates. Decrease in coelomocyte aggregation in earthworm collected from contaminated sites suggested a state of inappropriate shift of the innate immune status. Toxin-induced oxidative stress and reductions in cell aggregation response are the signs of immunocompromisation of M. posthuma. Present findings bear a prospect of this experimental species as an indicator of soil pollution.


Assuntos
Coelomomyces/fisiologia , Metais/toxicidade , Oligoquetos/fisiologia , Poluentes do Solo/toxicidade , Agricultura , Animais , Antioxidantes/metabolismo , Cádmio/metabolismo , Catalase/metabolismo , Agregação Celular , Monitoramento Ambiental , Poluição Ambiental , Glutationa Transferase/metabolismo , Índia , Mineração , Oligoquetos/metabolismo , Estresse Oxidativo , Espécies Reativas de Oxigênio/metabolismo , Solo , Poluentes do Solo/análise , Poluentes do Solo/metabolismo , Superóxido Dismutase/metabolismo , Superóxidos/metabolismo
5.
IET Nanobiotechnol ; 13(2): 230-236, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31051456

RESUMO

The present study was designed to check the role of silver nanoparticles (AgNPs) on physiological, biochemical parameters and antioxidants of wheat (Triticum aestivum L.) under heat stress. Plant extract of Moringa oleifera was used for AgNPs synthesis followed by characterization through UV-Vis spectroscopy, SEM, XRD and Zeta analyser. Heat stress was applied in range of 35-40°C for 3 hrs/ day for 3 days to wheat plants at trifoliate stage. Heat stress decreased the RWC (13.2%), MSI (16.3%), chl a (5.2%), chl b (4.1%) and TCCs (9.9%). Wheat plants treated with AgNPs showed significant increase in RWC (12.2%), MSI (26.5%), chl a (10%), chl b (16.4%), TCCs (19%), TPC (2.4%), TFC (2.5%), TASC (2.5%), SOD (1.3%), POX (1.5%), CAT (1.8%), APX (1.2%) and GPX (1.4%), under heat stress. Lower concentration of AgNPs (50 mg/l) decreased the sugar (5.8%) and proline contents (4%), while increase was observed in higher AgNPs concentrations. Overall, AgNPs treatment enhanced thermo-tolerance in wheat plants, but the mechanism of AgNPs action needs further investigation at genome and proteome level in wheat plants under heat stress.


Assuntos
Antioxidantes/farmacologia , Resposta ao Choque Térmico/efeitos dos fármacos , Nanopartículas Metálicas/química , Prata/farmacologia , Triticum/efeitos dos fármacos , Antioxidantes/química , Poluentes Ambientais/química , Poluentes Ambientais/farmacologia , Resposta ao Choque Térmico/fisiologia , Moringa oleifera/química , Extratos Vegetais/química , Extratos Vegetais/metabolismo , Prata/química , Superóxidos/metabolismo , Triticum/química , Triticum/metabolismo , Triticum/fisiologia
6.
J Plant Physiol ; 238: 20-28, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31125706

RESUMO

The aim of this study was to observe the possible function of increased superoxide and NO production in the response of barley root tip to the harmful level of Cd. While superoxide generation was detected only in the transition zone, the formation of NO was observed in the apical elongation zones of the control root tips. However, the root region with the superoxide generation was also associated with peroxynitrite specific fluorescence signal. Superoxide, H2O2 and peroxynitrite generation increased with Cd treatment in a dose-dependent manner. In turn, NO level increased at low 10-20 µM but decreased at high 50-60 µM Cd concentrations in comparison with the control. While co-treatment of roots with rotenone markedly attenuated the Cd-induced superoxide generation and lipid peroxidation, it increased the level of NO in the root tips. Although rotenone did not influence the Cd-induced increase of GPX activity at 10-30 µM Cd concentrations, it markedly reversed the high 40-60 µM Cd concentrations-induced decline of GPX activity. Cd-induced cell death was associated with robust superoxide generation, but not with a high level of peroxynitrite. The Cd-evoked inhibition of root growth was significantly reversed by a strong antioxidant N-acetyl cysteine but not by a peroxynitrite scavenger uric acid, suggesting that similarly to Cd-induced cell death, an imbalance in the ROS homeostasis and not an enhanced level of peroxynitrite is responsible for the Cd-induced root growth inhibition. Based on these findings, it can be assumed that NO acts mainly in the regulation of superoxide level in the tips of root. Under Cd stress, the enhanced NO level is involved in the scavenging of highly toxic superoxide through the formation of peroxynitrite, thus reducing the superoxide-mediated cell death in barley root.


Assuntos
Cádmio/toxicidade , Hordeum/efeitos dos fármacos , Meristema/efeitos dos fármacos , Óxido Nítrico/metabolismo , Ácido Peroxinitroso/metabolismo , Superóxidos/metabolismo , Morte Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Hordeum/metabolismo , Peróxido de Hidrogênio/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Meristema/metabolismo , Espécies Reativas de Oxigênio/metabolismo
7.
Plant Sci ; 283: 366-374, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31128707

RESUMO

The tau (U) and phi (F) classes of glutathione transferase (GST) enzymes reduce the glutathione (GSH) pool using GSH as a co-substrate, thus influence numerous redox-dependent processes including hormonal and stress responses. We performed detailed analysis of the redox potential and reactive oxygen species levels in longitudinal zones of 7-day-old roots of Arabidopsis thaliana L. Col-0 wild type and Atsgtf8 and Atgstu19 insertional mutants. Using redox-sensitive cytosolic green fluorescent protein (roGFP2) the redox status of the meristematic, transition, and elongation zones was determined under control and salt stress (3-hour of 75 or 150 mM NaCl treatment) conditions. The Atgstu19 mutant had the most oxidized redox status in all root zones throughout the experiments. Using fluorescent dyes significantly higher superoxide radical (O2-) levels was detected in both Atgst mutants than in the Col-0 control. Salt treatment resulted in the highest O2- increase in the Atgstf8 root, while the amount of H2O2 elevated most in the case of Atgstu19. Moreover, vitality decreased in Atgstu19 roots more than in wild type under salt stress. Our results indicate that AtGSTF8 and especially the AtGSTU19 proteins function in the root fine-tuning the redox homeostasis both under control and salt stress conditions.


Assuntos
Proteínas de Arabidopsis/fisiologia , Arabidopsis/fisiologia , Glutationa Transferase/fisiologia , Meristema/fisiologia , Raízes de Plantas/fisiologia , Arabidopsis/enzimologia , Arabidopsis/metabolismo , Homeostase , Peróxido de Hidrogênio/metabolismo , Meristema/metabolismo , Oxirredução , Raízes de Plantas/enzimologia , Raízes de Plantas/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Estresse Salino , Superóxidos/metabolismo
8.
Adv Exp Med Biol ; 1127: 85-95, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31140173

RESUMO

Arachidonic acid (AA) is a polyunsaturated fatty acid that participates in the inflammatory response mainly through bioactive-lipids formation in macrophages and also in the phagocytic NADPH oxidase 2 (NOX2) activation. NOX2 is the enzyme responsible for a huge superoxide formation in macrophages, essential to eliminate pathogens inside the phagosome. The oxidase is an enzymatic complex comprised of a membrane-bound flavocytochrome b 558 (gp91phox/p22phox), three cytosolic subunits (p47phox, p40phox and p67phox) and a Rac-GTPase. The enzyme becomes active when macrophages are exposed to appropriate stimuli that trigger the phosphorylation of cytosolic subunits and its migration to plasmatic membrane to form the active complex. It is proposed that AA stimulates NOX2 activity through AA interaction with different components of the NADPH oxidase complex. In inflammatory conditions, there is an increase in reactive oxygen and nitrogen species that results in the production of nitrated derivatives of AA, such as nitroarachidonic acid (NO2-AA). NO2-AA is capable to inhibit NOX2 activity by interfering with p47phox migration to the membrane without affecting phosphorylation of cytosolic proteins. Also, NO2-AA is capable to interact with protein disulfide isomerase (PDI), which is involved on NOX2 active complex formation. It has been demonstrated that NO2-AA forms a covalent adduct with PDI that could prevent the interaction with NOX2 and it would explain the inhibitory effects of the fatty acid upon NOX2. Together, current data indicate that AA is an important activator of NOX2 formed in the early events of the inflammatory response, leading to a massive production of oxidants that may, in turn, promote NO2-AA formation and shutting down the oxidative burst. Hence, AA and its derivatives could have antagonistic roles on NOX2 activity regulation.


Assuntos
Ácido Araquidônico/metabolismo , Inflamação/metabolismo , NADPH Oxidase 2/metabolismo , Humanos , Macrófagos/metabolismo , Fosfoproteínas/metabolismo , Fosforilação , Espécies Reativas de Nitrogênio/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Explosão Respiratória , Superóxidos/metabolismo
9.
BMC Complement Altern Med ; 19(1): 88, 2019 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-31023287

RESUMO

BACKGROUND: Stevia rebaudiana Bertoni has various pharmacological actions, which includes antidiabetic, antioxidant, anti-inflammatory activities. The superoxide and consequently NADPH oxidase (Nox) are relevant targets involved in biological effects of Stevia. The presence of NADPH-containing superoxide-producing lipoprotein (suprol) in Stevia leaves has not yet been tested. The mechanism of producing superoxide radicals (O2-) by suprol was determined in vitro, which is associated with the electron transfer from NADPH in the composition of suprol by traces of transition metal ions (Fe3+ or Cu2+) to molecular oxygen, turning it into O2-. It is expected that the therapeutic efficacy of Stevia leaves is caused by specific activity of superoxide-producing lipoprotein fraction. METHODS: For the first time, from the dry leaves of Stevia the NADPH-containing superoxide-producing lipoprotein was isolated and purified. The specific content of suprol (milligrams in 1 g of Stevia leaves- mg/g) was determined after desalination of suprol and lyophilization. RESULTS: According to the method provided, the specific content of the isolated suprol from Stevia's leaves was up to 4.5 ± 0.2 mg / g (yields up to 68.5 ± 4.7%, p < 0.05, n = 6). Nox forms a stable complex with suprol. The optical absorption spectrum of the Nox-suprol complex represents the overlapping suprol and Nox spectra, with a certain background increase and characteristic features of optical absorption for Nox. Due to O2- producing capacity suprol-Nox complex discolors KMnO4 solutions, Coomassie brilliant blue, restores nitrotetrazolium blue to formazan and oxidizes epinephrine to adrenochrome. The oxidation activity of adrenaline is 50.3 ± 5.1 U / mg / ml (p < 0.05, n = 6). CONCLUSION: Superoxide-producing lipoprotein fraction-Nox complex from Stevia leaves (membranes) can modulate redox regulated signaling pathways and may play a positive role in type-2 diabetes by means of adrenaline oxidation mechanism.


Assuntos
Lipoproteínas , NADP , Proteínas de Plantas , Stevia/química , Superóxidos , Lipoproteínas/química , Lipoproteínas/metabolismo , NADP/química , NADP/metabolismo , NADPH Oxidases/química , NADPH Oxidases/metabolismo , Oxirredução , Extratos Vegetais/química , Extratos Vegetais/metabolismo , Folhas de Planta/química , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Superóxidos/química , Superóxidos/metabolismo
10.
Nat Commun ; 10(1): 1914, 2019 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-31015473

RESUMO

Degradation of extracellular matrix (ECM) underlies loss of cartilage tissue in osteoarthritis, a common disease for which no effective disease-modifying therapy currently exists. Here we describe BNTA, a small molecule with ECM modulatory properties. BNTA promotes generation of ECM components in cultured chondrocytes isolated from individuals with osteoarthritis. In human osteoarthritic cartilage explants, BNTA treatment stimulates expression of ECM components while suppressing inflammatory mediators. Intra-articular injection of BNTA delays the disease progression in a trauma-induced rat model of osteoarthritis. Furthermore, we identify superoxide dismutase 3 (SOD3) as a mediator of BNTA activity. BNTA induces SOD3 expression and superoxide anion elimination in osteoarthritic chondrocyte culture, and ectopic SOD3 expression recapitulates the effect of BNTA on ECM biosynthesis. These observations identify SOD3 as a relevant drug target, and BNTA as a potential therapeutic agent in osteoarthritis.


Assuntos
Anti-Inflamatórios/farmacologia , Benzamidas/farmacologia , Cartilagem Articular/efeitos dos fármacos , Matriz Extracelular/efeitos dos fármacos , Depuradores de Radicais Livres/farmacologia , Fatores Imunológicos/farmacologia , Osteoartrite/tratamento farmacológico , Sulfonamidas/farmacologia , Animais , Cartilagem Articular/imunologia , Cartilagem Articular/patologia , Condrócitos/efeitos dos fármacos , Condrócitos/imunologia , Condrócitos/patologia , Citocinas/genética , Citocinas/imunologia , Modelos Animais de Doenças , Progressão da Doença , Matriz Extracelular/imunologia , Matriz Extracelular/patologia , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Humanos , Injeções Intra-Articulares , Masculino , Osteoartrite/genética , Osteoartrite/imunologia , Osteoartrite/patologia , Cultura Primária de Células , Ratos , Ratos Sprague-Dawley , Superóxido Dismutase/genética , Superóxido Dismutase/imunologia , Superóxidos/antagonistas & inibidores , Superóxidos/metabolismo , Transcriptoma/imunologia
11.
Food Chem ; 289: 369-376, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-30955625

RESUMO

The effects of postharvest treatment with sodium silicate (Si) (100 mM) on mitochondrial ROS production and energy metabolism of the muskmelon fruits (cv. Yujinxiang) on development of defense responses to Trichothecium roseum were studied. Si treatment decreased decay severity of inoculated muskmelons, enhanced the activities of energy metabolism of key enzymes and kept the intracellular ATP at a higher level; meanwhile, Si also induced the mtROS accumulation such as H2O2 and superoxide anion. TMT-based quantitative proteomics analysis revealed that a total of 24 proteins with significant differences in abundance involved in energy metabolism, defense and stress responses, glycolytic and TCA cycle, and oxidation-reduction process. It is suggested by our study that melon fruit mitochondria, when induced by Si treatments, play a key role in priming of host resistance against T. roseum infection through the regulation of energy metabolism and ROS production in the pathogen infected muskmelon fruits.


Assuntos
Cucumis , Metabolismo Energético/efeitos dos fármacos , Frutas/metabolismo , Mitocôndrias/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Silicatos/farmacologia , Trifosfato de Adenosina/análise , Frutas/efeitos dos fármacos , Peróxido de Hidrogênio/metabolismo , Oxirredução , Doenças das Plantas/prevenção & controle , Proteínas/metabolismo , Superóxidos/metabolismo
12.
Mar Drugs ; 17(4)2019 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-31013895

RESUMO

A previous report indicated that collagen hydrolysate fraction (F7) from Spanish mackerel (Scomberomorous niphonius) skins showed high reducing power and radical scavenging activities on 2,2-Diphenyl-1-picrylhydrazyl (DPPH) (EC50 value of 1.57 mg/mL) and hydroxyl (EC50 value of 1.20 mg/mL). In this work, eight peptides were isolated from F7 and identified as Gly-Pro-Tyr (GPY, 335.31 Da), Gly-Pro-Thr-Gly-Glu (GPTGE, 459.47 Da), Pro-Phe-Gly-Pro-Asp (PFGPD, 531.52 Da), Gly-Pro-Thr-Gly-Ala-Lys (GPTGAKG, 586.65 Da), Pro-Tyr-Gly-Ala-Lys-Gly (PYGAKG, 591.69 Da), Gly-Ala-Thr-Gly-Pro-Gln-Gly (GATGPQG, 586.61 Da), Gly-Pro-Phe-Gly-Pro-Met (GPFGPM, 604.73 Da), and Tyr-Gly-Pro-Met (YGPM, 466.50 Da), respectively. Among them, PFGPD, PYGAKG, and YGPM exhibited strong radical scavenging activities on DPPH (EC50 values of 0.80, 3.02, and 0.72 mg/mL for PFGPD, PYGAKG, and YGPM, respectively), hydroxyl (EC50 values of 0.81, 0.66, and 0.88 mg/mL for PFGPD, PYGAKG, and YGPM, respectively), superoxide anion (EC50 values of 0.91, 0.80, and 0.73 mg/mL for PFGPD, PYGAKG, and YGPM, respectively), and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) cation (EC50 values of 0.86, 1.07, and 0.82 mg/mL for PFGPD, PYGAKG, and YGPM, respectively) in a positive concentration-activity relationship. Furthermore, PFGPD, PYGAKG, and YGPM could effectively reduce Fe3+ to Fe2+ and inhibit lipid peroxidation. Hence, eight collagen peptides from hydrolysate of Spanish mackerel skins might be served as antioxidant candidates for various industrial applications.


Assuntos
Antioxidantes/química , Colágeno/química , Colágeno/farmacologia , Peptídeos/química , Peptídeos/farmacologia , Perciformes/metabolismo , Pele/química , Animais , Antioxidantes/farmacologia , Peroxidação de Lipídeos/efeitos dos fármacos , Hidrolisados de Proteína/metabolismo , Superóxidos/metabolismo
13.
Int J Mol Sci ; 20(7)2019 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-30974814

RESUMO

Manganese-dependent superoxide dismutase (MnSOD, SodA) and iron-dependent SOD (FeSOD, SodB) are critical cytosolic enzymes for alleviating superoxide stress. Distinct from the singular sodA gene in most bacteria, Stenotrophomonas maltophilia harbors two sodA genes, sodA1 and sodA2. The roles of SodA1, SodA2, and SodB of S. maltophilia in alleviating superoxide stress were investigated. The expression of sod genes was determined by promoter-xylE transcriptional fusion assay and qRT-PCR. SodA2 and sodB expressions were proportional to the bacterial logarithmic growth, but unaffected by menadione (MD), iron, or manganese challenges. SodA1 was intrinsically unexpressed and inducibly expressed by MD. Complementary expression of sodA1 was observed when sodA2 was inactivated. The individual or combined sod deletion mutants were constructed using the gene replacement strategy. The functions of SODs were assessed by evaluating cell viabilities of different sod mutants in MD, low iron-stressed, and/or low manganese-stressed conditions. Inactivation of SodA1 or SodA2 alone did not affect bacterial viability; however, simultaneously inactivating sodA1 and sodA2 significantly compromised bacterial viability in both aerobic growth and stressed conditions. SodA1 can either rescue or support SodA2 when SodA2 is defective or insufficiently potent. The presence of two MnSODs gives S. maltophilia an advantage against superoxide stress.


Assuntos
Proteínas de Bactérias/metabolismo , Estresse Oxidativo , Stenotrophomonas maltophilia/enzimologia , Superóxido Dismutase/metabolismo , Superóxidos/metabolismo , Proteínas de Bactérias/genética , Stenotrophomonas maltophilia/genética , Superóxido Dismutase/genética
14.
Cell Biol Int ; 43(6): 678-694, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30977575

RESUMO

We sought to determine the mechanism by which angiotensin II (ANGII) stimulates NADPH oxidase-mediated superoxide (O2 .- ) production in bovine pulmonary artery smooth muscle cells (BPASMCs). ANGII-induced increase in phospholipase D (PLD) and NADPH oxidase activities were inhibited upon pretreatment of the cells with chemical and genetic inhibitors of PLD2, but not PLD1. Immunoblot study revealed that ANGII treatment of the cells markedly increases protein kinase C-α (PKC-α), -δ, -ε, and -ζ levels in the cell membrane. Pretreatment of the cells with chemical and genetic inhibitors of PKC-ζ, but not PKC-α, -δ, and -ε, attenuated ANGII-induced increase in NADPH oxidase activity without a discernible change in PLD activity. Transfection of the cells with p47phox small interfering RNA inhibited ANGII-induced increase in NADPH oxidase activity without a significant change in PLD activity. Pretreatment of the cells with the chemical and genetic inhibitors of PLD2 and PKC-ζ inhibited ANGII-induced p47phox phosphorylation and subsequently translocation from cytosol to the cell membrane, and also inhibited its association with p22phox (a component of membrane-associated NADPH oxidase). Overall, PLD-PKCζ-p47phox signaling axis plays a crucial role in ANGII-induced increase in NADPH oxidase-mediated O2 .- production in the cells.


Assuntos
Angiotensina II/farmacologia , NADPH Oxidases/metabolismo , Fosfolipase D/metabolismo , Angiotensina II/metabolismo , Angiotensina II/fisiologia , Animais , Bovinos , Técnicas de Cultura de Células/métodos , Membrana Celular/metabolismo , Miócitos de Músculo Liso/metabolismo , NADPH Oxidases/fisiologia , Oxirredução , Fosfolipase D/antagonistas & inibidores , Fosfoproteínas/metabolismo , Fosforilação , Proteína Quinase C/metabolismo , Proteína Quinase C-alfa/metabolismo , Artéria Pulmonar/metabolismo , Transdução de Sinais/efeitos dos fármacos , Superóxidos/metabolismo
15.
Plant Cell Rep ; 38(7): 793-801, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30968200

RESUMO

KEY MESSAGE: Arabidopsis GI negatively regulates chloroplast biogenesis and resistance to the herbicide butafenacil by enhanced activity and transcriptional levels of antioxidant enzymes Chloroplast biogenesis is blocked by retrograde signaling triggered by diverse internal and external cues, including sugar, reactive oxygen species (ROS), phytohormones, and abiotic stress. Efficient chloroplast biogenesis is essential for crop productivity due to its effect on photosynthetic efficiency, and is associated with agronomic traits such as insect/disease resistance, herbicide resistance, and abiotic stress tolerance. Here, we show that the circadian clock-controlled gene GIGANTEA (GI) regulates chloroplast biogenesis in Arabidopsis thaliana. The gi-2 mutant showed reduced sensitivity to the chloroplast biogenesis inhibitor lincomycin, maintaining high levels of photosynthetic proteins. By contrast, wild-type and GI-overexpressing plants were sensitive to lincomycin, with variegated leaves and reduced photosynthetic protein levels. GI is degraded by lincomycin, suggesting that GI is genetically linked to chloroplast biogenesis. The GI mutant alleles gi-1 and gi-2 were resistant to the herbicide butafenacil, which inhibits protoporphyrinogen IX oxidase activity and triggers ROS-mediated cell death via the accumulation of chlorophyll precursors. Butafenacil-mediated accumulation of superoxide anions and H2O2 was not detected in gi-1 or gi-2, as revealed by histochemical staining. The activities of the antioxidant enzymes superoxide dismutase, peroxidase, and catalase were 1.2-1.4-fold higher in both gi mutants compared to the wild type. Finally, the expression levels of antioxidant enzyme genes were 1.5-2-fold higher in the mutants than in the wild type. These results suggest that GI negatively regulates chloroplast biogenesis and resistance to the herbicide butafenacil, providing evidence for a genetic link between GI and chloroplast biogenesis, which could facilitate the development of herbicide-resistant crops.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/efeitos dos fármacos , Arabidopsis/metabolismo , Herbicidas/farmacologia , Hidrocarbonetos Fluorados/farmacologia , Pirimidinas/farmacologia , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Cloroplastos/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/genética , Peróxido de Hidrogênio/metabolismo , Superóxidos/metabolismo
16.
BMC Plant Biol ; 19(1): 152, 2019 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-31010418

RESUMO

BACKGROUND: During sexual reproduction, pollen grains land on the stigma, rehydrate and produce pollen tubes that grow through the female transmitting-tract tissue allowing the delivery of the two sperm cells to the ovule and the production of healthy seeds. Because pollen tubes are single cells that expand by tip-polarized growth, they represent a good model to study the growth dynamics, cell wall deposition and intracellular machineries. Aiming to understand this complex machinery, we used a low throughput chemical screen approach in order to isolate new tip-growth disruptors. The effect of a chemical inhibitor of monogalactosyldiacylglycerol synthases, galvestine-1, was also investigated. The present work further characterizes their effects on the tip-growth and intracellular dynamics of pollen tubes. RESULTS: Two small compounds among 258 were isolated based on their abilities to perturb pollen tube growth. They were found to disrupt in vitro pollen tube growth of tobacco, tomato and Arabidopsis thaliana. We show that these 3 compounds induced abnormal phenotypes (bulging and/or enlarged pollen tubes) and reduced pollen tube length in a dose dependent manner. Pollen germination was significantly reduced after treatment with the two compounds isolated from the screen. They also affected cell wall material deposition in pollen tubes. The compounds decreased anion superoxide accumulation, disorganized actin filaments and RIC4 dynamics suggesting that they may affect vesicular trafficking at the pollen tube tip. CONCLUSION: These molecules may alter directly or indirectly ROP1 activity, a key regulator of pollen tube growth and vesicular trafficking and therefore represent good tools to further study cellular dynamics during polarized-cell growth.


Assuntos
Arabidopsis/crescimento & desenvolvimento , Tubo Polínico/crescimento & desenvolvimento , Bibliotecas de Moléculas Pequenas/farmacologia , Citoesqueleto de Actina/efeitos dos fármacos , Citoesqueleto de Actina/metabolismo , Actinas/metabolismo , Arabidopsis/efeitos dos fármacos , Parede Celular/efeitos dos fármacos , Parede Celular/metabolismo , Germinação/efeitos dos fármacos , Conformação Molecular , Tubo Polínico/efeitos dos fármacos , Bibliotecas de Moléculas Pequenas/química , Superóxidos/metabolismo
17.
Pestic Biochem Physiol ; 156: 116-122, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31027570

RESUMO

Cucumber mosaic virus (CMV) is a plant virus with one of the largest host ranges, the widest distribution, and economic importance, and ningnanmycin (NNM) is a commercial antiviral agent. Studies have shown that NNM induces and promotes pathogenesis-related proteins in tobacco mosaic virus-inoculated tobacco. In the present study, the defense enzymes and the biochemical factors of CMV-inoculated tobacco treated with NNM were measured. The biochemical factors of CMV-inoculated tobacco leaves treated with NNM were analyzed. Results showed that the phenylalanine ammonia-lyase, peroxidase, polypheuoloxidase, and superoxide in the CMV-inoculated tobacco leaves treated with NNM were higher than those in non-treated tobacco leaves. Furthermore, NNM activated the oxidation-reduction process, metabolic process, and oxidoreductase activity in the CMV-infected tobacco.


Assuntos
Cucumovirus/patogenicidade , Citidina/análogos & derivados , Tabaco/metabolismo , Tabaco/virologia , Citidina/farmacologia , Oxirredução , Peroxidase , Fenilalanina Amônia-Liase/metabolismo , Doenças das Plantas/virologia , Folhas de Planta/metabolismo , Folhas de Planta/virologia , Superóxidos/metabolismo
18.
MBio ; 10(2)2019 03 12.
Artigo em Inglês | MEDLINE | ID: mdl-30862752

RESUMO

There is a growing appreciation within animal and plant physiology that the reactive oxygen species (ROS) superoxide is not only detrimental but also essential for life. Yet, despite widespread production of extracellular superoxide by healthy bacteria and phytoplankton, this molecule remains associated with stress and death. Here, we quantify extracellular superoxide production by seven ecologically diverse bacteria within the Roseobacter clade and specifically target the link between extracellular superoxide and physiology for two species. We reveal for all species a strong inverse relationship between cell-normalized superoxide production rates and cell number. For exponentially growing cells of Ruegeria pomeroyi DSS-3 and Roseobacter sp. strain AzwK-3b, we show that superoxide levels are regulated in response to cell density through rapid modulation of gross production and not decay. Over a life cycle of batch cultures, extracellular superoxide levels are tightly regulated through a balance of both production and decay processes allowing for nearly constant levels of superoxide during active growth and minimal levels upon entering stationary phase. Further, removal of superoxide through the addition of exogenous superoxide dismutase during growth leads to significant growth inhibition. Overall, these results point to tight regulation of extracellular superoxide in representative members of the Roseobacter clade, consistent with a role for superoxide in growth regulation as widely acknowledged in fungal, animal, and plant physiology.IMPORTANCE Formation of reactive oxygen species (ROS) through partial reduction of molecular oxygen is widely associated with stress within microbial and marine systems. Nevertheless, widespread observations of the production of the ROS superoxide by healthy and actively growing marine bacteria and phytoplankton call into question the role of superoxide in the health and physiology of marine microbes. Here, we show that superoxide is produced by several marine bacteria within the widespread and abundant Roseobacter clade. Superoxide levels outside the cell are controlled via a tightly regulated balance of production and decay processes in response to cell density and life stage in batch culture. Removal of extracellular superoxide leads to substantial growth inhibition. These findings point to an essential role for superoxide in the health and growth of this ubiquitous group of microbes, and likely beyond.


Assuntos
Oxidantes/metabolismo , Roseobacter/crescimento & desenvolvimento , Roseobacter/metabolismo , Superóxidos/metabolismo , Carga Bacteriana , Meios de Cultura/química
19.
J Photochem Photobiol B ; 193: 100-108, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30826583

RESUMO

Silver nanoparticles (AgNPs) have been widely recognized as antibacterial agents. However, its stability and activity over time have been poorly studied. In this work, the properties and characteristics of differently stabilized AgNPs were evaluated during a span of time. The surface capping agents were diclofenac (d), and ketorolac (k), which currently are used as anti-inflammatory in human medicine. On evaluating the size variation over time, it was observed that the AgNPs-k are the most stable, unlike the non-capped nanoparticles agglomerate and precipitate. UV-Vis spectroscopy analysis showed that the absorbance during time decreases for the three types of nanoparticles, but the decrease is less marked for the two types of anti-inflammatory-capped AgNPs. The rapid loss of the optical prop- erties of bare AgNPs, is mainly due to oxidation, agglomeration, and precipitation of this nanoparticles. The potential cytotoxicity of the AgNPs, evaluated through the formation of the superoxide anion using XXT, showed that both, AgNPs-k and AgNPs-d, generate the radical anion when the samples are irradiated with UV light at 365 nm. This effect appears associated with the capping agents, since the bare nanoparticles did not promote the formation of the superoxide anion. The antibacterial activity of the AgNPs throughout time, against two microorganisms (Escherichia coli and Staphylococcus aureus), was also evaluated. The results showed that capping agents played a decisive role in the antibacterial ability of AgNPs and also in enhancing the antibacterial activity over time.


Assuntos
Antibacterianos/química , Anti-Inflamatórios/química , Nanopartículas Metálicas/química , Prata/química , Superóxidos/metabolismo , Ânions/química , Antibacterianos/farmacologia , Diclofenaco/química , Difusão Dinâmica da Luz , Escherichia coli/efeitos dos fármacos , Cetorolaco/química , Ligantes , Nanopartículas Metálicas/toxicidade , Testes de Sensibilidade Microbiana , Microscopia Eletrônica de Transmissão , Espectrofotometria , Staphylococcus aureus/efeitos dos fármacos , Raios Ultravioleta
20.
Int J Mol Sci ; 20(5)2019 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-30866540

RESUMO

Melatonin (MT; N-acetyl-5-methoxytryptamine) is a pleiotropic signaling molecule that has been demonstrated to play an important role in plant growth, development, and regulation of environmental stress responses. Studies have been conducted on the role of the exogenous application of MT in a few species, but the potential mechanisms of MT-mediated stress tolerance under salt stress are still largely unknown. In this study, naked oat seedlings under salt stress (150 mM NaCl) were pretreated with two different concentrations of MT (50 and 100 µM), and the effects of MT on the growth and antioxidant capacity of naked oat seedlings were analyzed to explore the regulatory effect of MT on salt tolerance. The results showed that pretreating with different concentrations of MT promoted the growth of seedlings in response to 150 mM NaCl. Different concentrations of MT reduced hydrogen peroxide, superoxide anion, and malondialdehyde contents. The exogenous application of MT also increased superoxide dismutase, peroxidase, catalase, and ascorbate peroxide activities. Chlorophyll content, leaf area, leaf volume, and proline increased in the leaves of naked oat seedlings under 150 mM NaCl stress. MT upregulated the expression levels of the lipid peroxidase genes lipoxygenase and peroxygenase, a chlorophyll biosynthase gene (ChlG), the mitogen-activated protein kinase genes Asmap1 and Aspk11, and the transcription factor genes (except DREB2), NAC, WRKY1, WRKY3, and MYB in salt-exposed MT-pretreated seedlings when compared with seedlings exposed to salt stress alone. These results demonstrate an important role of MT in the relief of salt stress and, therefore, provide a reference for managing salinity in naked oat.


Assuntos
Antioxidantes/farmacologia , Avena/crescimento & desenvolvimento , Melatonina/farmacologia , Proteínas de Plantas/genética , Tolerância ao Sal , Avena/efeitos dos fármacos , Avena/metabolismo , Relação Dose-Resposta a Droga , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Peróxido de Hidrogênio/metabolismo , Malondialdeído/metabolismo , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Plântula/metabolismo , Superóxidos/metabolismo
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