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1.
Mar Environ Res ; 156: 104919, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32056798

RESUMO

This study investigated the role of the feeding regime on cellular (lysosomal membrane impairment), oxidative (superoxides and nitric oxides generation, as well as lipid peroxidation) and genotoxic (nuclear abnormalities) biomarkers measured in hemocytes of mussels Mytilus galloprovincialis treated with diclofenac (DCF). Specifically, unfed mussels, or mussels fed ad libitum with algal species Tisochrysis lutea or Tetraselmis suecica (Tiso/DCF- and Tetra/DCF- treated mussels, respectively) were exposed to DCF (20 µgL-1) for 4 days. The results showed that biomarkers' responsiveness against DCF, were more pronounced in unfed and Tetra/DCF-, rather than Tiso/DCF- treated mussel hemocytes, thus revealing food deprivation, changes in mussel feeding/filtration rate and digestion processes, as potent factors of mussels' immune efficiency and response against DCF. Those findings could provide valuable data for the optimization of mussels' feeding regime during laboratory studies, in order to assess reliably the effects of emerging contaminants on non-target sentinel organisms, such as mussels.


Assuntos
Biomarcadores/análise , Diclofenaco/toxicidade , Mytilus/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais , Peroxidação de Lipídeos , Lisossomos , Óxido Nítrico/análise , Superóxidos/análise
2.
Biosens Bioelectron ; 148: 111799, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31675611

RESUMO

Smart and green construction of noble metal nanostructures on two-dimensional nanomaterials-based flexible paper-like materials have gained extensive attention due to the formed hybrid papers have shown great promise in the applications of energy devices, sensing electronics, actuators, and chemical filters. Herein, a cost-effective and environment-friendly strategy to realize the spontaneous growth of noble metal nanoparticles (Au, Pd, and Pt) on flexible biomimetic MXene paper was proposed. The self-defined regulation of formed noble metal nanoparticles could be easily achieved, and the bimetallic (AuPt, PdPt) nanoparticles decorated MXene paper could be obtained at the mean time. These findings bring a simple, efficient and green way for constructing various hybrid MXene paper with outperforming electrocatalytic activities, which was demonstrated by the sensitive detection of superoxide (O2•-) and the good stability and reproducibility after a long-term usage. The outstanding analytical performance of the obtained AuPtNPs/MXene paper in O2•- monitoring leads to a satisfactory application in real-time extracellular biosensing. The investigation for spontaneous growth and regulation of noble metal nanoparticles on flexible biomimetic MXene paper exhibits a huge application potential for constructing high-performance flexible bioelectronics and energy-related devices.


Assuntos
Materiais Biomiméticos/química , Técnicas Biossensoriais/métodos , Nanopartículas Metálicas/química , Superóxidos/análise , Biomimética/métodos , Ouro/química , Células Hep G2 , Humanos , Limite de Detecção , Nanopartículas Metálicas/ultraestrutura , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Paládio/química , Papel , Platina/química
3.
Free Radic Res ; 53(11-12): 1135-1143, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31744337

RESUMO

As mitochondrial superoxide is becoming an attractive metabolic and pharmacological target, there is an important need for developing analytical tools able to detect superoxide with high sensitivity and specificity. Among EPR-based methods, it has been recently reported that cyclic hydroxylamines offer a high sensitivity to measure superoxide production. Here, we report the synthesis and evaluation of mitoCPH, in which a 5-membered ring hydroxylamine was coupled to a triphenylphosphonium moiety to allow mitochondrial accumulation. MitoCPH efficiently reacted with superoxide with a bimolecular rate constant of 1.5 × 104 M-1 s-1. We assessed the ability of this compound to detect superoxide in PBS buffer, lysates, and in paraquat-stimulated cells. We compared its performance with CMH, a nontargeted 5-membered ring hydroxylamine, and mitoTEMPO-H, a classically used 6-membered ring hydroxylamine targeted to mitochondria. MitoCPH presented a higher sensitivity for superoxide anion detection than commonly used mitoTEMPO-H, both in buffer and in cell lysates. While we have described the ability of mitoCPH to detect superoxide in different cellular media, we cannot exclude other potential contributors to the nitroxide production from this probe. Therefore, mitoCPH should be considered as a mitochondria-targeted probe and its use as selective superoxide probe should be used cautiously.


Assuntos
Hidroxilamina/química , Mitocôndrias/química , Compostos Organofosforados/química , Superóxidos/análise , Linhagem Celular , Espectroscopia de Ressonância de Spin Eletrônica , Humanos , Hidroxilamina/síntese química , Mitocôndrias/metabolismo , Estrutura Molecular , Óxidos de Nitrogênio/análise , Óxidos de Nitrogênio/metabolismo , Superóxidos/metabolismo
4.
Biosensors (Basel) ; 9(4)2019 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-31623083

RESUMO

BACKGROUND: In vitro cell culture monitoring can be used as an indicator of cellular oxidative stress for the assessment of different chemotherapy agents. METHODS: A cell-based bioelectric biosensor was used to detect alterations in superoxide levels in the culture medium of HeLa cervical cancer cells after treatment with the chemotherapeutic agent 5-fluorouracil (5-FU). The cytotoxic effects of 5-fluorouracil on HeLa cells were assessed by the MTT proliferation assay, whereas oxidative damage and induction of apoptosis were measured fluorometrically by the mitochondria-targeted MitoSOX™ Red and caspase-3 activation assays, respectively. RESULTS: The results of this study indicate that 5-FU differentially affects superoxide production and caspase-3 activation when applied in cytotoxic concentrations against HeLa cells, while superoxide accumulation is in accordance with mitochondrial superoxide levels. Our findings suggest that changes in superoxide concentration could be detected with the biosensor in a non-invasive and rapid manner, thus allowing a reliable estimation of oxidative damage due to cell apoptosis. CONCLUSIONS: These findings may be useful for facilitating future high throughput screening of different chemotherapeutic drugs with a cytotoxic principle based on free radical production.


Assuntos
Antimetabólitos Antineoplásicos/farmacologia , Técnicas Biossensoriais , Fluoruracila/farmacologia , Superóxidos/análise , Antimetabólitos Antineoplásicos/química , Apoptose/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Fluoruracila/química , Células HeLa , Humanos , Mitocôndrias/química , Mitocôndrias/metabolismo , Superóxidos/metabolismo
5.
Exp Parasitol ; 207: 107770, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31586454

RESUMO

Neutrophils respond differently to violations of the body's physiological barriers during infections. Extracellular traps comprise one of the mechanisms used by these cells to reduce the spread of pathogens to neighboring tissues, as well as ensure a high concentration of antimicrobial agents at the site of infection. To date, this innate defense mechanism has not been previously demonstrated in neutrophils of cats exposed to Toxoplasma gondii. The aim of this study was to characterize the in vitro release of neutrophil extracellular traps (NETs) when neutrophils isolated from cats were exposed to T. gondii. First, cellular viability was tested at different time points after parasite exposure. The production of reactive oxygen species (ROS) and lactate dehydrogenase and the amount of extracellular DNA were quantified. In addition, the number of parasites associated with neutrophils was determined, and the observed NETs formed were microscopically characterized. Results showed that (i) in culture, neutrophils isolated from cats presented diminished cellular viability after 4 h of incubation, and when neutrophils were incubated with T. gondii, they displayed cytotoxic effects after 3 h of interaction; (ii) neutrophils were able to release structures composed of DNA and histones, characterized as NETs under optical, immunofluorescence, and electron scanning microscopy, when stimulated with T. gondii; (iii) only 11.4% of neutrophils were able to discharge NETs during 3 h of incubation; however, it was observed through extracellular quantification of DNA that this small number of cells were able to display different behavior compared to a negative control (no parasite) group; (iv) significant differences in ROS production were observed in neutrophils exposed to T. gondii. In conclusion, our results showed that neutrophils isolated from cats exposed to T. gondii release structures composed of DNA and histones, similar to what has already been described in other neutrophil species infected with the parasite.


Assuntos
Armadilhas Extracelulares/metabolismo , Neutrófilos/parasitologia , Toxoplasma/imunologia , Animais , Gatos , Sobrevivência Celular , Chlorocebus aethiops , DNA/análise , Formazans/metabolismo , L-Lactato Desidrogenase/metabolismo , Microscopia Eletrônica de Varredura , Microscopia de Fluorescência , Neutrófilos/imunologia , Neutrófilos/ultraestrutura , Espécies Reativas de Oxigênio/metabolismo , Superóxidos/análise , Sais de Tetrazólio/metabolismo , Células Vero
6.
Molecules ; 24(18)2019 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-31500271

RESUMO

Garlic and formulations containing allicin are used widely as fungicides in modern agriculture. However, limited reports are available on the allelopathic mechanism of green garlic volatile organic compounds (VOCs) and its component allelochemicals. The aim of this study was to investigate VOCs of green garlic and their effect on scavenging of reactive oxygen species (ROS) in cucumber. In this study, green garlic VOCs were collected by HS-SPME, then analyzed by GS-MS. Their biological activity were verified by bioassays. The results showed that diallyl disulfide (DADS) is the main allelochemical of green garlic VOCs and the DADS content released from green garlic is approximately 0.08 mg/g. On this basis, the allelopathic effects of green garlic VOCs in vivo and 1 mmol/L DADS on scavenging of ROS in cucumber seedlings were further studied. Green garlic VOCs and DADS both reduce superoxide anion and increase the accumulation of hydrogen peroxide of cucumber seedlings. They can also regulate active antioxidant enzymes (SOD, CAT, POD), antioxidant substances (MDA, GSH and ASA) and genes (CscAPX, CsGPX, CsMDAR, CsSOD, CsCAT, CsPOD) responding to oxidative stress in cucumber seedlings.


Assuntos
Compostos Alílicos/farmacologia , Cucumis sativus/metabolismo , Dissulfetos/farmacologia , Alho/química , Espécies Reativas de Oxigênio/análise , Compostos Alílicos/isolamento & purificação , Cucumis sativus/efeitos dos fármacos , Cucumis sativus/genética , Dissulfetos/isolamento & purificação , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Peróxido de Hidrogênio/análise , Estresse Oxidativo/efeitos dos fármacos , Feromônios/isolamento & purificação , Feromônios/farmacologia , Proteínas de Plantas/genética , Plântula/efeitos dos fármacos , Plântula/metabolismo , Superóxidos/análise , Compostos Orgânicos Voláteis/química , Compostos Orgânicos Voláteis/isolamento & purificação
7.
Chem Commun (Camb) ; 55(73): 10912-10915, 2019 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-31441468

RESUMO

A novel AIE probe with ESIPT characteristics, myricetin, has been easily purified from vine tea for reversible, selective and sensitive targeting of O2˙- in turn-on mode. Its AIE nanocrystals exhibit large Stokes shift, high photostability, excellent biocompatibility, and low cytotoxicity for endogenous O2˙- detection and imaging in vitro and in vivo.


Assuntos
Flavonoides/química , Corantes Fluorescentes/química , Superóxidos/análise , Ampelopsis/química , Animais , Feminino , Flavonoides/isolamento & purificação , Flavonoides/toxicidade , Fluorescência , Corantes Fluorescentes/isolamento & purificação , Corantes Fluorescentes/toxicidade , Células HeLa , Humanos , Camundongos Endogâmicos ICR , Nanopartículas/química , Nanopartículas/toxicidade , Oxirredução , Espectrometria de Fluorescência/métodos , Superóxidos/química
8.
J Trace Elem Med Biol ; 55: 96-106, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31345373

RESUMO

Leaf senescence is a genetically programmed process that can also be induced by nitrogen (N) deficiency. Although selenium (Se) delays leaf senescence, the underlying mechanisms are still unknown. To explore the mechanisms of Se-mediated delay of leaf senescence, we studied the biochemical and molecular events that occur during developmental and N deficiency-induced senescence. Oilseed rape (Brassica napus L.) plants were grown under adequate N (AN, 16 mM) or low N (LN, 4 mM) conditions during the rosette growth stage and treated with Se (15 µg plant-1 as Na2SeO4) either through roots or leaves for four weeks. Shoot dry matter production was not influenced, while the photosynthetic parameters were improved by Se application in both young and old leaves under both AN and LN conditions. The Se treatment rarely influenced the concentrations of reactive oxygen species (ROS), while it increased the nitric oxide (NO) levels in young and old leaves under both AN and LN conditions. The positive correlation between the NO level and leaf photosynthetic parameters in old leaves of LN plants suggested a role for NO boosting, mediated by Se, in the protection of aging leaves from LN-induced accelerated senescence. This implication was further supported by the clear down-regulation of SAG12-1 and up-regulation of Cab, particularly by root application of Se in old leaves of LN plants. Our results provide the first evidence that Se influences the expression of senescence-associated genes and delays senescence through NO signalling but is independent of the ROS defence system.


Assuntos
Brassica napus/metabolismo , Folhas de Planta/metabolismo , Selênio/metabolismo , Sequência de Aminoácidos , Brassica napus/química , Brassica napus/genética , Óxido Nítrico/análise , Óxido Nítrico/metabolismo , Processos Fotoquímicos , Folhas de Planta/química , Selênio/química , Superóxidos/análise , Superóxidos/metabolismo
9.
Biomed Chromatogr ; 33(10): e4630, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31243785

RESUMO

A new capillary electrophoresis method was developed to study the synergistic effect of superoxide dismutase and jujuboside A or B on scavenging superoxide anion radical in serum matrix respectively, in which superoxide anion radical was generated from pyrogallol autoxidation. The electrophoresis conditions, and the factors affecting the productive rate of purpurogallin, such as pyrogallol autoxidation product and the activity of superoxide dismutase, were optimized. Under optimal conditions, the content of superoxide dismutase in Gibco newborn calf serum was 7.06 mg/L, RSD was 2.01% and the average recovery was 98.4%. The values of IC50 for jujuboside A and B in the serum matrix were 157.67 and 31.60 mg/L respectively, and they both had synergy on scavenging superoxide anion radical with superoxide dismutase, but there was no the dose-dependency on this synergy.


Assuntos
Eletroforese Capilar/métodos , Saponinas/farmacologia , Superóxido Dismutase/farmacologia , Superóxidos , Ânions/análise , Ânions/metabolismo , Sinergismo Farmacológico , Depuradores de Radicais Livres/farmacologia , Modelos Lineares , Pirogalol/análise , Pirogalol/química , Pirogalol/metabolismo , Reprodutibilidade dos Testes , Superóxidos/análise , Superóxidos/metabolismo
10.
Chem Commun (Camb) ; 55(54): 7836-7839, 2019 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-31215559

RESUMO

It is of great importance to determine the superoxide anion (O2˙-), a kind of active free radical that plays important roles in catalytic and biological processes. We present here a high-energy-state biomimetic enzyme with extraordinary activity for O2˙- by inducing surface oxygen defects in MnTiO3 nanodiscs. Oxygen defects enable surface rich active Mn sites with high oxidation ability, which significantly promote the adsorption and electro-oxidation of O2˙-. The oxygen deficient MnTiO3 towards O2˙- exhibits a sensitivity of 126.48 µA µM-1 cm-2 and a detection limit of 1.54 nM, among the best performance of O2˙- sensing platforms.


Assuntos
Materiais Biomiméticos/química , Compostos de Manganês/química , Nanoestruturas/química , Óxidos/química , Superóxidos/análise , Titânio/química , Técnicas Eletroquímicas/métodos , Limite de Detecção , Oxirredução , Oxirredutases/química
11.
Mikrochim Acta ; 186(6): 370, 2019 05 22.
Artigo em Inglês | MEDLINE | ID: mdl-31119470

RESUMO

Two kinds of carbon-based nanozymes were constructed from the same precursor of zeolitic imidazolate framework-8 (ZIF-8) for O2•- determination. Hollow carbon cubic nanomaterial (labelled as HCC) was obtained by chemically etching ZIF-8 with tannic acid and a subsequent calcination. A porous carbon cubic nanomaterial (labelled as PCC) was prepared by directly pyrolysis. Then HCC and PCC were immobilized on the surface of screen printed carbon electrodes (SPCE), fabricating HCC and PCC modified electrodes (denoted as HCC/SPCE and PCC/SPCE). HCC/SPCE, best operated at -0.5 V (vs. Ag/AgCl), has a sensitivity of 6.55 × 102 nA µM-1 cm-2 with a detection limit of 207 nM (at S/N = 3) for O2•- sensing. And PCC/SPCE, best operated at -0.4 V (vs. Ag/AgCl), exhibited a superior performance for O2•- detection with a sensitivity of 1.14 × 103 nA µM-1 cm-2 and a low detection limit of 140 nM (at S/N = 3). The two sensors possess excellent reproducibility and stability. They were used to sense O2•- released from HeLa cells. Graphical abstract Illustration of the synthesis of the hollow carbon cubic nanomaterial (HCC) and of the porous carbon cubic nanomaterial (PCC), and the scheme for detection of superoxide anions in HeLa cell.


Assuntos
Carbono/química , Técnicas Eletroquímicas/métodos , Nanoestruturas/química , Superóxidos/análise , Técnicas Eletroquímicas/instrumentação , Eletrodos , Células HeLa , Humanos , Limite de Detecção , Oxirredução , Reprodutibilidade dos Testes , Oxigênio Singlete/química , Superóxidos/metabolismo , Zeolitas/química , Zimosan/farmacologia
12.
Microb Pathog ; 130: 226-231, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30872146

RESUMO

We evaluated the inactivation of DNA gyrase on the oxidative stress response and sensitivity of A. baumannii to lophirones B and C. The sensitivity of parental and the mutant strains of A. baumannii to lophirones B and C was determined using minimum inhibitory concentration (MIC) and time-kill sensitivity. Inactivation of sodB, katG, recA enhanced the sensitivity of A. baumannii to lophirones B and C. Furthermore, this inactivation increased the accumulation of superoxide anion radical and hydrogen peroxide in lophirones B and C-treated A. baumannii, which was reversed in the presence of thiourea. Inactivation of gyrA stalled lophirones B and C-mediated ROS accumulation in A. baumannii. In addition, lophirones B and C raised the Fe2+ contents of A. baumannii. Dipyridyl (Fe chelator) reversed the sensitivity of A. baumannii to lophirones B and C. Lophirones significantly lowered the NAD+/NADH ratio of A. baumannii. The results of this study revealed that the impact of DNA gyrase in lophirones B and C-mediated ROS accumulation, Fe2+ release and cell death.


Assuntos
Acinetobacter baumannii/efeitos dos fármacos , Antibacterianos/farmacologia , Chalconas/farmacologia , DNA Girase/metabolismo , Estresse Oxidativo , Inibidores da Topoisomerase II/farmacologia , Acinetobacter baumannii/enzimologia , Peróxido de Hidrogênio/análise , Ferro/análise , Testes de Sensibilidade Microbiana , Viabilidade Microbiana/efeitos dos fármacos , Superóxidos/análise
13.
Mikrochim Acta ; 186(3): 198, 2019 02 22.
Artigo em Inglês | MEDLINE | ID: mdl-30796529

RESUMO

A sensor is described for determination of superoxide anion (O2˙-). The electrode consists of nitrogen-doped cotton carbon fiber (NCFs) modified with silver nanoparticles (AgNPs) which have excellent catalytic capability. The resulting sensor, best operated at working potentials around -0.5 V (vs. SCE), can detect O2˙- over an extraordinarily wide range that covers 10 orders of magnitude, and the detection limit is 2.32 ± 0.07 fM. The electrode enables the release of O2˙- from living cells under normal or under oxidative stress conditions to be determined. The ability to scavenge the superoxide anions of antioxidants was also investigated. In the authors' perception, the method represents a viable tool for studying diseases related to oxidative stress. Graphical abstract Schematic presentation of the construction of an electrochemical sensor based on Nitrogen-doped cotton carbon fiber and silver nanoparticles. It can be used for the direct detection of superoxide anions released from Glioma cells (U87) under normal or under oxidative stress conditions.


Assuntos
Fibra de Carbono/química , Fibra de Algodão , Superóxidos/análise , Antioxidantes/análise , Técnicas Biossensoriais , Catálise , Linhagem Celular Tumoral , Técnicas Eletroquímicas , Eletrodos , Humanos , Limite de Detecção , Nanopartículas Metálicas/química , Oxirredução , Estresse Oxidativo , Tamanho da Partícula , Prata/química , Propriedades de Superfície
14.
Talanta ; 197: 239-248, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-30771930

RESUMO

Monitoring superoxide anion radical (O2•-) in live cells and in vivo is of great significance since O2•- is the precursor of other reactive oxygen species and has been closely associated with various physiological and pathological processes. Herein, we developed a novel mitochondria-targeted fluorescent probe PF-MitoSOX Green in which the phosphinate moiety is utilized to recognize O2•- with high sensitivity and selectivity. Confocal imaging results illustrated that PF-MitoSOX Green can not only detect intracellular O2•-, but also can conveniently visualize its production in cells and Caenorhabditis elegans. The present study illustrates that PF-MitoSOX Green provides a novel approach for imaging and detecting O2•- in live cells and in vivo.


Assuntos
Caenorhabditis elegans/química , Corantes Fluorescentes/química , Mitocôndrias/química , Imagem Óptica , Ácidos Fosfínicos/química , Superóxidos/análise , Animais , Linhagem Celular , Corantes Fluorescentes/síntese química , Estrutura Molecular , Ácidos Fosfínicos/síntese química , Ratos
15.
Analyst ; 144(5): 1704-1710, 2019 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-30657475

RESUMO

The superoxide anion (O2˙-) plays a crucial role in several physiological processes and many human diseases. Developing new methods for O2˙- detection in biological systems is very important. A FRET-based two-photon (TP) fluorescent probe with a ratiometric signal, TFR-O, was developed. A naphthalene derivative based TP fluorescent group was selected as the energy donor group, and a rhodol fluorescent group was chosen as the energy acceptor; the trifluoromethanesulfonate group was chosen as the recognition moiety. After reacting with O2˙-, the recognition moiety was removed and the fluorophore was released, leading to a fluorescence intensity decrease at the wavelength of 425 nm and a significant enhancement of the fluorescence intensity at 550 nm. The fluorescence intensity ratio between 550 and 425 nm (I550/I425) varied from 0.15 to 6.72, with the O2˙- concentration increasing from 0 to 50 µM. The detection limit of the TFR-O was 83 nM. Moreover, TFR-O was applied for detecting and imaging O2˙- in cells and liver tissues.


Assuntos
Fluoresceínas/química , Corantes Fluorescentes/química , Mesilatos/química , Naftalenos/química , Superóxidos/análise , Animais , Fluoresceínas/síntese química , Fluoresceínas/efeitos da radiação , Fluoresceínas/toxicidade , Fluorescência , Transferência Ressonante de Energia de Fluorescência/métodos , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/efeitos da radiação , Corantes Fluorescentes/toxicidade , Limite de Detecção , Fígado/metabolismo , Mesilatos/síntese química , Mesilatos/efeitos da radiação , Mesilatos/toxicidade , Camundongos , Naftalenos/síntese química , Naftalenos/efeitos da radiação , Naftalenos/toxicidade , Fótons , Células RAW 264.7 , Superóxidos/metabolismo
16.
Nanoscale ; 11(6): 2624-2630, 2019 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-30693354

RESUMO

The great challenge in preparing a biomimetic enzyme sensor is to have sensitivity and selectivity equal to or better than its corresponding biological sensor. Porous electrodes possess a large surface area and are often used to greatly improve the sensor sensitivity. However, how to tailor the pore structure, especially the pore size distribution to further improve the sensitivity and selectivity of a biomimetic sensor, has not been investigated yet. The superoxide anion (O2˙-) plays essential roles in various biological processes and is of importance in clinical diagnosis and life science research. It is generally detected by the superoxide dismutase enzyme. Herein, we delicately tailor the pore structure of carbon nanofibers (CNFs) by pyrolysis to obtain an optimal mesopore structure for strong adsorption of DNA, followed by guiding the growth of Mn3(PO4)2 as a biomimetic enzyme toward highly sensitive detection of O2˙-. The Mn3(PO4)2-DNA/CNF sensor achieves the best sensitivity among the reported O2˙- sensors while possessing good selectivity. The enhancement mechanism is also investigated, indicating that the mesopore ratio of CNFs plays an essential role in the high sensitivity and selectivity due to their strong adsorption of DNA for guiding the growth of a large amount of uniform sensing components, Mn3(PO4)2, toward high sensitivity and selectivity. The biomimetic sensor was further used to in situ monitor O2˙- released from human keratinocyte cells and human malignant melanoma cells under drug stimulation, showing high sensitivity to real-time quantitative detection of O2˙-. This work provides a highly sensitive in situ real-time biomimetic O2˙- sensor for applications in biological research and diagnosis, while shedding light on the enhancement mechanism of the pore structure, especially the pore size distribution of a porous electrode for high performance sensing processes.


Assuntos
Técnicas Biossensoriais/métodos , DNA , Enzimas , Nanotubos de Carbono/química , Compostos Organometálicos , Superóxidos/análise , Adsorção , Linhagem Celular Tumoral , DNA/química , DNA/metabolismo , Enzimas/química , Enzimas/metabolismo , Humanos , Nanofibras/química , Compostos Organometálicos/química , Compostos Organometálicos/metabolismo , Porosidade
17.
Br J Pharmacol ; 176(3): 386-399, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30403290

RESUMO

BACKGROUND AND PURPOSE: Glucagon-like peptide-1 (GLP-1) is an incretin hormone that regulates insulin biosynthesis and secretion in a glucose-dependent manner and has been reported to induce vasodilatation. Here, we examined the possible vasorelaxant effect of GLP-1 and its underlying mechanisms. EXPERIMENTAL APPROACH: Rat mesenteric arteries (diameter ≈ 200-400 µm) and human s.c. arteries were mounted in microvascular myographs for isometric tension recordings. The effect of GLP-1 on vascular responses was examined under normoglycaemic conditions and at high glucose concentrations. KEY RESULTS: In rat mesenteric arteries and human s.c. arteries without branches, physiological concentrations (1-100 nM) of GLP-1(7-36) and liraglutide failed to cause relaxation or affect contractions evoked by electrical field stimulation. In contrast to GLP-1(7-36), liraglutide induced relaxations antagonized by the GLP-1 receptor antagonist, exendin-(9-39), in branched mesenteric arteries. In contrast to liraglutide, GLP-1 leftward shifted the concentration relaxation curves for bradykinin in s.c. arteries from patients with peripheral arterial disease, an effect resistant to exendin-(9-39). Under normoglycaemic conditions, neither GLP-1 nor liraglutide affected ACh relaxation in rat mesenteric arteries. In arteries exposed to 40 mM glucose, GLP-1, in contrast to liraglutide, potentiated ACh-induced relaxation by a mechanism that was not antagonized by exendin-(9-39). GLP-1 decreased superoxide levels measured with dihydroethidium in rat mesenteric arteries exposed to 40 mM glucose. CONCLUSIONS AND IMPLICATIONS: GLP-1 receptors are involved in the liraglutide-induced relaxation of branched arteries, under normoglycaemic conditions, while GLP-1 inhibition of vascular superoxide levels contributes to GLP-1 receptor-independent potentiation of endothelium-dependent vasodilatation in hyperglycaemia.


Assuntos
Peptídeo 1 Semelhante ao Glucagon/farmacologia , Liraglutida/farmacologia , Artérias Mesentéricas/efeitos dos fármacos , Vasodilatação/efeitos dos fármacos , Animais , Relação Dose-Resposta a Droga , Receptor do Peptídeo Semelhante ao Glucagon 1/agonistas , Receptor do Peptídeo Semelhante ao Glucagon 1/metabolismo , Masculino , Artérias Mesentéricas/metabolismo , Miócitos de Músculo Liso/efeitos dos fármacos , Miócitos de Músculo Liso/metabolismo , Ratos , Ratos Wistar , Relação Estrutura-Atividade , Superóxidos/análise , Superóxidos/metabolismo
18.
J Mater Chem B ; 7(3): 401-407, 2019 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-32254727

RESUMO

Transition metal phosphates have shown great potential as nanozymes for selective detection of reactive oxygen species (ROS), but its application has been hindered by the complicated synthesis and difficulty in shape and size control. Herein, we present a facile method to fabricate transition metal phosphates by using hollow carbon structures as substrates. Manganese phosphate is a typical Nanozyme used in this design and the shape and size of the Mnx(PO4)y layer can be efficiently controlled by altering the carbon substrates. Characterization demonstrated that Mnx(PO4)y layer modified hollow carbon sphere (Mn-MPSA-HCS) and hollow carbon cubic (Mn-MPSA-HCC) were successfully prepared and used as nanozymes for superoxide detection. The established electrochemical sensor was employed in the online monitoring of drug stimulated superoxide anions released from cancer cells. This method can be adapted as a general way to prepare transition metal phosphate layers with various controllable shapes and sizes as nanozymes for different uses in the future.


Assuntos
Carbono/química , Nanopartículas/química , Compostos Organometálicos/química , Superóxidos/análise , Ânions/análise , Técnicas Eletroquímicas , Células HeLa , Humanos , Tamanho da Partícula , Porosidade , Propriedades de Superfície
19.
Cell Death Dis ; 9(11): 1097, 2018 10 26.
Artigo em Inglês | MEDLINE | ID: mdl-30367086

RESUMO

We investigated the role of oxidative stress and the inflammasome in trauma-induced axon degeneration and vision loss using a mouse model. The left eyes of male mice were exposed to over-pressure air waves. Wild-type C57Bl/6 mice were fed normal, high-vitamin-E (VitE), ketogenic or ketogenic-control diets. Mice lacking the ability to produce vitamin C (VitC) were maintained on a low-VitC diet. Visual evoked potentials (VEPs) and retinal superoxide levels were measured in vivo. Tissue was collected for biochemical and histological analysis. Injury increased retinal superoxide, decreased SOD2, and increased cleaved caspase-1, IL-1α, IL-1ß, and IL-18 levels. Low-VitC exacerbated the changes and the high-VitE diet mitigated them, suggesting that oxidative stress led to the increase in IL-1α and activation of the inflammasome. The injury caused loss of nearly 50% of optic nerve axons at 2 weeks and astrocyte hypertrophy in mice on normal diet, both of which were prevented by the high-VitE diet. The VEP amplitude was decreased after injury in both control-diet and low-VitC mice, but not in the high-VitE-diet mice. The ketogenic diet also prevented the increase in superoxide levels and IL-1α, but had no effect on IL-1ß. Despite this, the ketogenic diet preserved optic nerve axons, prevented astrocyte hypertrophy, and preserved the VEP amplitude. These data suggest that oxidative stress induces priming and activation of the inflammasome pathway after neurotrauma of the visual system. Further, blocking the activation of the inflammasome pathway may be an effective post-injury intervention.


Assuntos
Antioxidantes/uso terapêutico , Ácido Ascórbico/uso terapêutico , Inflamação/prevenção & controle , Traumatismos do Nervo Óptico/dietoterapia , Traumatismos do Nervo Óptico/tratamento farmacológico , Retina/lesões , Vitamina E/uso terapêutico , Animais , Antioxidantes/farmacologia , Ácido Ascórbico/farmacologia , Axônios/metabolismo , Dieta Cetogênica , Modelos Animais de Doenças , Potenciais Evocados Visuais , Inflamassomos/metabolismo , Interleucina-1alfa/metabolismo , Interleucina-1beta/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Estresse Oxidativo/fisiologia , Espécies Reativas de Oxigênio/metabolismo , Superóxidos/análise
20.
Crit Care ; 22(1): 269, 2018 10 27.
Artigo em Inglês | MEDLINE | ID: mdl-30367644

RESUMO

BACKGROUND: Sepsis and related multiple organ dysfunction result in high morbidity and mortality. Angiotensin (Ang)-(1-7), a biologically active peptide, has various opposing effects of Ang II. Because the effect of Ang-(1-7) on sepsis is unknown, in this study we aimed to determine the impact of Ang-(1-7) on pathophysiologic changes in a clinically relevant model of polymicrobial sepsis induced by cecal ligation and puncture (CLP). METHODS: Sepsis was induced by CLP in rats under anesthesia. Rats were randomized to one of the following five groups: (1) sham-operated group, (2) Ang-(1-7) (1 mg/kg intravenously infused for 1 h) at 3 h and 6 h after sham operation, (3) CLP, (4) Ang-(1-7) at 3 h after CLP, and (5) Ang-(1-7) at 3 h and 6 h after CLP. Rats were observed for 24 h after CLP surgery and then killed for subsequent histological examination. RESULTS: Ang-(1-7) significantly improved the survival of septic rats (83.3% vs. 36.4% at 24 h following CLP; p = 0.009). Ang-(1-7) attenuated the CLP-induced decreased arterial pressure and organ dysfunction, indicated by diminished biochemical variables and fewer histological changes. Ang-(1-7) significantly reduced the level of plasma interleukin-6 and pulmonary superoxide production (p < 0.05). Moreover, caspase-3 and cytoplasmic IκB expression in liver was significantly lower in the Ang-(1-7)-treated CLP rats (p < 0.05). CONCLUSIONS: In this clinically relevant model of sepsis, Ang-(1-7) ameliorates CLP-induced organ dysfunction and improves survival, possibly through suppressing the inflammatory response, oxidative stress, and apoptosis, suggesting that Ang-(1-7) could be a potential novel therapeutic approach to treatment of peritonitis and polymicrobial sepsis.


Assuntos
Angiotensina I/farmacologia , Fragmentos de Peptídeos/farmacologia , Sepse/mortalidade , Sobrevivência de Tecidos/fisiologia , Angiotensina I/uso terapêutico , Animais , Apoptose/fisiologia , Biomarcadores/análise , Biomarcadores/sangue , Coinfecção/mortalidade , Modelos Animais de Doenças , Interleucina-6/análise , Interleucina-6/sangue , Escores de Disfunção Orgânica , Estresse Oxidativo , Fragmentos de Peptídeos/uso terapêutico , Ratos , Ratos Wistar , Estatísticas não Paramétricas , Superóxidos/análise , Superóxidos/sangue
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