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1.
Food Chem ; 333: 127492, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-32659673

RESUMO

In this study, recombinant rice quiescin sulfhydryl oxidase (rQSOX) was expressed and characterized, and its performance in flour-processing quality was further evaluated. The purified rQSOX exhibited the highest sulfhydryl oxidation activity (1.96 IU/mg) using dithiothreitol as a substrate, accompanying the production of H2O2. The optimal temperature and pH were 60 °C and pH 8.0 for rQSOX catalyzing oxidation of dithiothreitol. And rQSOX retained 50% of its maximum activity after incubation at 80 °C for 1 h. Moreover, rQSOX supplementation improved the farinograph properties of dough, indicated by the increased dough stability time and decreased degree of softening, and enhanced viscoelastic properties of the dough. Addition of rQSOX (10 IU/g flour) provided remarkable improvement in specific volume (37%) and springiness (17%) of the steamed bread, and significantly reduced the hardness by half, which was attributed to the strengthened gluten network. The results provide an understanding for rQSOX using in flour-processing industry.


Assuntos
Farinha/análise , Oryza/enzimologia , Oxirredutases/química , Proteínas de Plantas/química , Triticum/química , Biocatálise , Pão/análise , Manipulação de Alimentos , Glutens/química , Dureza , Peróxido de Hidrogênio/análise , Oryza/química , Oryza/genética , Oxirredutases/genética , Oxirredutases/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo
2.
Chemosphere ; 259: 127396, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32645596

RESUMO

The performance of the UV/H2O2 advanced oxidation process (AOP) is dependent on water quality parameters, including the UV absorbance coefficient at 254 nm and hydroxyl radical (•OH) water background demand (scavenging factor, s-1). The •OH scavenging factor represents the •OH scavenging rate of the background substances in the water matrix, and it is known to be one of the key parameters to predict the performance of the UV/H2O2 process. The •OH scavenging factor has been determined experimentally by using a probe compound such as pCBA and rhodamine B. The experimental method has been validated to accurately predict the micropollutants removal in the UV/H2O2 process, but there is a need for an easier and simple method of determining the OH scavenging factor. We evaluated the alternative method to analyze the •OH scavenging factor using fluorescence excitation-emission matrix and parallel factor analysis (F-EEM/PARAFAC). The correlation between •OH scavenging factor and the spectroscopic characteristics and structure of different organic matter types was evaluated. Organic matter was characterized using a fluorescence excitation-emission matrix, parallel factor analysis, and liquid chromatography-organic carbon detection. Second-order reaction rates of humic acid sodium salt, sodium alginate, Suwannee River humic acid and bovine serum albumin were calculated as 1.30 × 108 M-1 s-1, 1.39 × 108 M-1 s-1, 1.03 × 108 M-1 s-1, and 3.17 × 107 M-1 s-1, respectively. Results of PARAFAC analysis, the ratio of humic and fulvic fluorescence component 2 to terrestrial humic-like fluorescence component 1 (C2/C1), and •OH scavenging factor showed high linearity. A predictive model, which combines with the F-EEM/PARAFAC method, predicted the optimal UV and H2O2 dose to achieve target compound removal.


Assuntos
Poluentes Químicos da Água/química , Purificação da Água/métodos , Análise Fatorial , Fluorescência , Substâncias Húmicas/análise , Peróxido de Hidrogênio/análise , Radical Hidroxila/química , Oxirredução , Rios/química , Espectrometria de Fluorescência/métodos , Água/análise , Poluentes Químicos da Água/análise , Qualidade da Água
3.
Int J Mol Sci ; 21(15)2020 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-32717853

RESUMO

As SARS-CoV-2 is spreading rapidly around the globe, adopting proper actions for confronting and protecting against this virus is an essential and unmet task. Reactive oxygen species (ROS) promoting molecules such as peroxides are detrimental to many viruses, including coronaviruses. In this paper, metal decorated single-wall carbon nanotubes (SWCNTs) were evaluated for hydrogen peroxide (H2O2) adsorption for potential use for designing viral inactivation surfaces. We employed first-principles methods based on the density functional theory (DFT) to investigate the capture of an individual H2O2 molecule on pristine and metal (Pt, Pd, Ni, Cu, Rh, or Ru) decorated SWCNTs. Although the single H2O2 molecule is weakly physisorbed on pristine SWCNT, a significant improvement on its adsorption energy was found by utilizing metal functionalized SWCNT as the adsorbent. It was revealed that Rh-SWCNT and Ru-SWCNT systems demonstrate outstanding performance for H2O2 adsorption. Furthermore, we discovered through calculations that Pt- and Cu-decorated SWNCT-H2O2 systems show high potential for filters for virus removal and inactivation with a very long shelf-life (2.2 × 1012 and 1.9 × 108 years, respectively). The strong adsorption of metal decorated SWCNTs and the long shelf-life of these nanomaterials suggest they are exceptional candidates for designing personal protection equipment against viruses.


Assuntos
Betacoronavirus/efeitos dos fármacos , Desinfetantes/farmacologia , Peróxido de Hidrogênio/análise , Nanotubos de Carbono/química , Adsorção , Infecções por Coronavirus/prevenção & controle , Teoria da Densidade Funcional , Desinfetantes/química , Estabilidade de Medicamentos , Humanos , Ferro/química , Ferro/farmacologia , Pandemias/prevenção & controle , Equipamento de Proteção Individual , Platina/química , Platina/farmacologia , Pneumonia Viral/prevenção & controle , Ródio/química , Ródio/farmacologia , Rutênio/química , Rutênio/farmacologia , Inativação de Vírus
4.
Proc Natl Acad Sci U S A ; 117(22): 12017-12028, 2020 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-32434917

RESUMO

Synthetic chemical elicitors, so called plant strengtheners, can protect plants from pests and pathogens. Most plant strengtheners act by modifying defense signaling pathways, and little is known about other mechanisms by which they may increase plant resistance. Moreover, whether plant strengtheners that enhance insect resistance actually enhance crop yields is often unclear. Here, we uncover how a mechanism by which 4-fluorophenoxyacetic acid (4-FPA) protects cereals from piercing-sucking insects and thereby increases rice yield in the field. Four-FPA does not stimulate hormonal signaling, but modulates the production of peroxidases, H2O2, and flavonoids and directly triggers the formation of flavonoid polymers. The increased deposition of phenolic polymers in rice parenchyma cells of 4-FPA-treated plants is associated with a decreased capacity of the white-backed planthopper (WBPH) Sogatella furcifera to reach the plant phloem. We demonstrate that application of 4-PFA in the field enhances rice yield by reducing the abundance of, and damage caused by, insect pests. We demonstrate that 4-FPA also increases the resistance of other major cereals such as wheat and barley to piercing-sucking insect pests. This study unravels a mode of action by which plant strengtheners can suppress herbivores and increase crop yield. We postulate that this represents a conserved defense mechanism of plants against piercing-sucking insect pests, at least in cereals.


Assuntos
Acetatos/farmacologia , Comportamento Alimentar/efeitos dos fármacos , Flavonoides , Hemípteros , Imunidade Vegetal/efeitos dos fármacos , Animais , Bioensaio , Produtos Agrícolas/efeitos dos fármacos , Flavonoides/análise , Flavonoides/metabolismo , Herbivoria , Hordeum/efeitos dos fármacos , Peróxido de Hidrogênio/análise , Peróxido de Hidrogênio/metabolismo , Oryza/efeitos dos fármacos , Peroxidases/análise , Peroxidases/metabolismo , Controle de Pragas/métodos , Folhas de Planta/química , Triticum/efeitos dos fármacos
5.
Chemosphere ; 254: 126773, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32334249

RESUMO

In this study, persulfate (PS) activated with microwave (MW) irradiation was used to treat strongly alkaline (pH = 12.70-12.80) wastewater containing dinitrodiazophenol (DDNP). The effects of key factors such as the PS dosage, MW output power, influent chemical oxygen demand (COD), and inorganic anions concentration were studied, and the presence of reactive oxygen species was monitored in the MW-PS process. The results showed that at a PS dosage of 6.0 g L-1, MW output power of 750 W, and reaction time of 16 min, the COD was reduced by 74.07% and the color number by 99.40%. In addition, the reaction during the MW-PS process for the treatment of industrial wastewater containing DDNP was comparatively stable and it was relatively unaffected by anions (i.e., chloride, carbonate, nitrate, and bicarbonate ions). Furthermore, SO4·-, OH·, and O2·- jointly degraded organics in the MW-PS process, and O2·- played a vital role in the degradation of organics in the industrial wastewater containing DDNP. Controlled experiments showed that the MW-PS process performed better than MW-H2O2 and ozonation processes in the treatment of alkaline industrial wastewater containing DDNP. Ultraviolet-visible and Fourier transform infrared spectroscopy analyses also indicated that refractory organic compounds with functional groups such as benzene rings, nitro groups (-NO2), and diazo groups (-NN-) were effectively decomposed in the MW-PS process and transformed into intermediate products that contained N-H and -OH. Overall, the MW-PS process was found to be highly effective in the treatment of a strongly alkaline wastewater containing DDNP.


Assuntos
Micro-Ondas , Sulfatos/química , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/química , Análise da Demanda Biológica de Oxigênio , Peróxido de Hidrogênio/análise , Compostos Orgânicos , Oxirredução , Águas Residuárias/química , Poluentes Químicos da Água/análise
6.
J Nutr ; 150(5): 1116-1125, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-32101618

RESUMO

BACKGROUND: Liver dysfunction impairs immunological homeostasis. Glycine (Gly) has been reported to have antioxidative and anti-inflammatory effects and to regulate apoptosis in various models. OBJECTIVES: The aim of the present study was to determine whether Gly could attenuate LPS-induced liver injury. METHODS: In Experiment 1, 48 6-week-old male C57BL/6 mice were randomly assigned into one of 4 groups: CON (control), GLY [orally administered Gly, 5 g · kg body weight (BW)-1 · d-1 for 6 d], LPS (5 mg/kg BW, intraperitoneally administered), and GLY + LPS (Gly supplementation, and on day 7 LPS treatment). In Experiment 2, mice were untreated, pretreated with Gly as above, or pretreated with Gly + l-buthionine sulfoximine (BSO) (0.5 g/kg BW, intraperitoneally administered every other day) for 6 d. On day 7, mice were injected with LPS as above. Histological alterations, activities of antioxidative enzymes, apoptosis, and immune cell infiltration were analyzed. RESULTS: In Experiment 1, compared with CON, LPS administration resulted in increased karyolysis and karyopyknosis in the liver by 8- to 10-fold, enhanced serum activities of alanine transaminase (ALT), aspartate transaminase (AST), and lactate dehydrogenase (LDH) by 1- to 1.8-fold, and increased hepatic apoptosis by 5.5-fold. Furthermore, LPS exposure resulted in increased infiltration of macrophages and neutrophils in the liver by 3.2- to 7.5-fold, elevated hepatic concentrations of malondialdehyde and hydrogen peroxide (H2O2), and elevated myeloperoxidase (MPO) activity by 1.5- to 6.3-fold. In Experiment 2, compared with the LPS group, mice in the GLY + LPS group had fewer histological alterations (68.5%-75.9%); lower serum ALT, AST, and LDH activities (24.3%-64.7%); and lower hepatic malondialdehyde and H2O2 concentrations (46.1%-80.2%), lower MPO activity (39.2%), immune cell infiltration (52.3%-85.3%), and apoptosis (69.6%), which were abrogated by BSO. Compared with the GLY + LPS group, mice in the GLY + BSO + LPS group had lower hepatic activities of catalase, superoxide dismutase, and glutathione peroxidase by 33.5%-48.5%; increased activation of NF-κB by 2.3-fold; and impaired nuclear factor (erythroid-derived 2)-like 2 signaling by 38.9%. CONCLUSIONS: Gly is a functional amino acid with an ability to protect the liver against LPS-induced injury in mice.


Assuntos
Apoptose/efeitos dos fármacos , Doença Hepática Induzida por Substâncias e Drogas/prevenção & controle , Glicina/farmacologia , Inflamação/prevenção & controle , Lipopolissacarídeos/administração & dosagem , Fígado/efeitos dos fármacos , Alanina Transaminase/sangue , Animais , Aspartato Aminotransferases/sangue , Doença Hepática Induzida por Substâncias e Drogas/patologia , Peróxido de Hidrogênio/análise , L-Lactato Desidrogenase/sangue , Fígado/química , Macrófagos/patologia , Masculino , Malondialdeído/análise , Camundongos , Camundongos Endogâmicos C57BL , Neutrófilos/patologia , Peroxidase/metabolismo
7.
Food Chem ; 315: 126296, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32014663

RESUMO

Some minor constituents of honey samples were determined through a fluorometric-chemical characterization method and related multifactorially with their antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa and with their geographical origin. Rotated principal component analysis identified five significant components in honey: three related to antibacterial activity and linked to phenolic compounds; Maillard products; proteins; the concentration of H2O2 at 3 and 24 h of incubation; and a tyrosine-containing entity. On the other hand, five constituents (phenolic compounds were the most relevant) allowed the classification of honey samples by geographical origin with 87% certainty. The results showed that phenolic compounds and Maillard products are related to the sustained production of H2O2 over time, which in turn boosts the antibacterial activity of honey. Native flora could promote this capability. The results showed the effect of geographic origin on the content of the analyzed minor constituents of honey, particularly phenolic compounds.


Assuntos
Mel/análise , Antibacterianos/farmacologia , Fluorometria , Peróxido de Hidrogênio/análise , Testes de Sensibilidade Microbiana , Fenóis/análise , Pseudomonas aeruginosa/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos
8.
Molecules ; 25(2)2020 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-31940924

RESUMO

Over the past few decades, nanostructured conducting polymers have received great attention in several application fields, including biosensors, microelectronics, polymer batteries, actuators, energy conversion, and biological applications due to their excellent conductivity, stability, and ease of preparation. In the bioengineering application field, the conducting polymers were reported as excellent matrixes for the functionalization of various biological molecules and thus enhanced their performances as biosensors. In addition, combinations of metals or metal oxides nanostructures with conducting polymers result in enhancing the stability and sensitivity as the biosensing platform. Therefore, several methods have been reported for developing homogeneous metal/metal oxide nanostructures thin layer on the conducting polymer surfaces. This review will introduce the fabrications of different conducting polymers nanostructures and their composites with different shapes. We will exhibit the different techniques that can be used to develop conducting polymers nanostructures and to investigate their chemical, physical and topographical effects. Among the various biosensors, we will focus on conducting polymer-integrated electrochemical biosensors for monitoring important biological targets such as DNA, proteins, peptides, and other biological biomarkers, in addition to their applications as cell-based chips. Furthermore, the fabrication and applications of the molecularly imprinted polymer-based biosensors will be addressed in this review.


Assuntos
Técnicas Biossensoriais , DNA/análise , Técnicas Eletroquímicas , Glucose/análise , Peróxido de Hidrogênio/análise , Nanoestruturas/química , Proteínas/análise , Animais , Compostos Bicíclicos Heterocíclicos com Pontes/química , Condutividade Elétrica , Humanos , Metais/química , Impressão Molecular/métodos , Óxidos/química , Polímeros/química , Piridinas/química
9.
Mikrochim Acta ; 187(2): 132, 2020 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-31942660

RESUMO

The multifunctional hemin@carbon dot hybrid nanozymes (hemin@CD) with simultaneous peroxidase-like activity and fluorescence signalling property was prepared for the first time. Based on these properties, hemin@CD was applied to develop a dual-channel fluorescent probe for H2O2 and H2O2-based biocatalytic systems. By virtue of the peroxidase-like activity, hemin@CD can catalyze the oxidative coupling of 4-aminoantipyrine with phenol in the presence of H2O2 to form a pink-red quinoneimine dye with a maximum absorbance at 505 nm. Under the excitation wavelength of 480 nm, the green fluorescence of hemin@CD peaks at 540 nm and is quenched by the generated quinoneimine dye due to an inner filter effect, and also by H2O2 because of dynamic quenching. Thus, a colorimetric and fluorimetric dual-channel optical probe for H2O2 is obtained. Due to the glucose/xanthine transformations under formation of H2O2 by the relevant oxidase catalysis, the probe can be applied for detection of glucose and xanthine. The colorimetric detection limits for H2O2, glucose and xanthine are 0.11, 0.15, 0.11 µM, and the and fluorimetric detection limits are 0.15, 0.15, 0.12 µM, respectively. Graphical abstractSchematic representation of the colorimetric and fluorimetric dual probe for H2O2, glucose and xanthine based on the multifunctional emin@carbon dot) hybrid nanozymes with simultaneous peroxidase-like activity and fluorescence signalling property.


Assuntos
Glucose/análise , Peróxido de Hidrogênio/análise , Xantina/análise , Biocatálise , Carbono , Colorimetria/métodos , Colorimetria/normas , Corantes Fluorescentes/química , Fluorometria/métodos , Fluorometria/normas , Hemina , Limite de Detecção , Mimetismo Molecular , Peroxidase/metabolismo
10.
Anal Chim Acta ; 1097: 230-237, 2020 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-31910964

RESUMO

With this research we presented a ratiometric and mitochondria-target fluorescent probe (Mito-HT) for detection of H2O2 both in vitro and in live cells. Mito-HT was constructed by direct conjugation of aryl boronate to fluorophore with three synthetic steps. The borate group is cleaved from Mito-HT in the presence of H2O2, resulting in the exposure of the hydroxyl group of the electron donating group. Then the ICT mechanism was turned on, and the fluorescence emission of Mito-HT at 493 nm was red-shifted to 562 nm, thereby achieving radiometric detection of H2O2. Mito-HT exhibited a highly selectivity towards H2O2, and this interaction can be completed within 40 min. Mito-HT could be used for quantitative detection of H2O2 (0-200 µM) through ratiometric fluorescence signal readout. And limit of detection (LOD) is approximately 0.33 µM. The relatively high stability and medium fluorescence quantum yield of Mito-HT (0.39) and Mito-HT-OH (0.43) enable clear mitochondria localization and dual-channel fluorescence imaging of H2O2 in live cells with confocal microscopy.


Assuntos
Corantes Fluorescentes/química , Peróxido de Hidrogênio/análise , Mitocôndrias/química , Animais , Células CHO , Sobrevivência Celular , Cricetulus , Corantes Fluorescentes/síntese química , Microscopia de Fluorescência , Estrutura Molecular , Fatores de Tempo
11.
Anal Chim Acta ; 1097: 78-84, 2020 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-31910972

RESUMO

A biomimetic assembly of per-O-methylated-cyclodextrin dimer with cobalt proto-porphyrin (CoIII-PPIX@Py2CD) was achieved via covalent linkage between CoIII of CoIII-PPIX and pyridine N of Py2CD (primarily synthesized by the acyl chlorination reaction of two ß-CDs monomers with 3,5-bis (bromomethyl) pyridine). Ultraviolet-visible (UV-vis) and circular dichroism (CD) absorption spectroscopy, and NMR hydrogen spectroscopy (H1-NMR) were adopted to carefully characterize the structure of Py2CD and its functional assembly with CoIII-PPIX. X-ray photoelectron spectroscopy (XPS) was employed to affirm the binding of the as-obtained CoIII-PPIX@Py2CD, whose electrochemical kinetics were extensively studied to validate the feasibility in the catalytic reduction of hydrogen peroxide (H2O2). The developed sensor displayed the wide linear range for H2O2 detection and the low detection limit of 2.47 × 10-7 M. This work sheds some constructive lights on rational design and synthesis of preeminently biomimic carrier and high cost-effectiveness catalyst for (bio)analytical applications.


Assuntos
Cobalto/química , Ciclodextrinas/química , Peróxido de Hidrogênio/análise , Porfirinas/química , Dimerização , Estrutura Molecular
12.
Ecotoxicol Environ Saf ; 190: 110123, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31891837

RESUMO

In this work, a novel manganese dioxide-graphene nanosheets (MnO2-GNSs) composite was synthesized by a facile one-step hydrothermal method, in which manganese dioxide (MnO2) was fabricated by hydrothermal reduction of KMnO4 with GNSs. The structure and morphology of MnO2-GNSs composite were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) analysis and X-ray photoelectron spectroscopy (XPS). A sensitive non-enzymatic electrochemical sensor based on MnO2-GNSs composite for the detection of low concentration hydrogen peroxide (H2O2) was fabricated. The electrochemical properties of MnO2-GNSs composite modified glassy carbon electrode (MnO2-GNSs/GCE) were investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and amperometry. The observations confirmed that the fabricated sensor exhibited high electrocatalytic activity for oxidation of H2O2 owing to the catalytic ability of MnO2 particles and the conductivity of GNSs. Under the optimum conditions, the calibration curve was linear for the amperometric response versus H2O2 concentration over the range 0.5-350 µM with a low detection limit of 0.19 µM (S/N = 3) and high sensitivity of 422.10 µA mM-1 cm-2. The determination and quantitative analysis of H2O2 in antiseptic solution on MnO2-GNSs/GCE exhibited percent recovery of 96.50%-101.22% with relative standard deviation (RSD) of 1.48%-4.47%. The developed MnO2-GNSs/GCE might be a promising platform for the practical detection of H2O2 due to its prominent properties including excellent reproducibility, good anti-interference and repeatability.


Assuntos
Técnicas Eletroquímicas/métodos , Grafite/química , Peróxido de Hidrogênio/análise , Compostos de Manganês/química , Modelos Químicos , Óxidos/química , Carbono/química , Catálise , Espectroscopia Dielétrica , Eletrodos , Limite de Detecção , Reprodutibilidade dos Testes
13.
Physiol Plant ; 168(3): 648-659, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31278755

RESUMO

The effects of low pH on antioxidant metabolism and nitrogen (N) assimilation in ginger seedlings under salt stress were investigated. A two-way randomized block design was used: the main treatment consisted of two pH levels, normal and low pH (6.0 and 4.0, respectively), and the other treatment consisted of two salinity levels, 0 and 100 mmol l-1 Na+ (NaCl and Na2 SO4 ). The results showed that low pH decreased the malondialdehyde (MDA) and hydrogen peroxide contents of ginger seedling leaves under salt stress. Moreover, low pH and salt stress significantly decreased the contents of non-enzymatic antioxidants, including ascorbate (AsA) and glutathione (GSH), and increased the activities of antioxidant enzymes, such as superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR) and glutathione reductase (GR). In addition, salt stress inhibited the N assimilation process in ginger seedling leaves, but low pH improved N assimilation under salt stress. Our finding was that low pH alleviated oxidative damage and promoted N assimilation under salt stress.


Assuntos
Antioxidantes/metabolismo , Gengibre/metabolismo , Nitrogênio/metabolismo , Estresse Salino , Ascorbato Peroxidases/metabolismo , Ácido Ascórbico/metabolismo , Catalase/metabolismo , Glutationa/metabolismo , Peróxido de Hidrogênio/análise , Concentração de Íons de Hidrogênio , Malondialdeído/análise , Estresse Oxidativo , Plântula/metabolismo , Superóxido Dismutase/metabolismo
14.
Physiol Plant ; 168(2): 345-360, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31343742

RESUMO

We conducted a study to evaluate the interactive effect of NO and H2 S on the cadmium (Cd) tolerance of wheat. Cadmium stress considerably reduced total dry weight, chlorophyll a and b content and ratio of Fv/Fm by 36.7, 48.6, 26.7 and 19.5%, respectively, but significantly enhanced the levels of hydrogen peroxide (H2 O2 ) and malondialdehyde (MDA), endogenous H2 S and NO, and the activities of antioxidant enzymes. Exogenously applied sodium nitroprusside (SNP) and sodium hydrosulfide (NaHS), donors of NO and H2 S, respectively, enhanced total plant dry matter by 47.8 and 39.1%, chlorophyll a by 92.3 and 61.5%, chlorophyll b content by 29.1 and 27.2%, Fv/Fm ratio by 19.7 and 15.2%, respectively, and the activities of antioxidant enzymes, but lowered oxidative stress and proline content in Cd-stressed wheat plants. NaHS and SNP also considerably limited both the uptake and translocation of Cd, thereby improving the levels of some key mineral nutrients in the plants. Enhanced levels of NO and H2 S induced by NaHS were reversed by hypotuarine application, but they were substantially reduced almost to 50% by cPTIO (a NO scavenger) application. Hypotuarine was not effective, but cPTIO was highly effective in reducing the levels of NO and H2 S produced by SNP in the roots of Cd-stressed plants. The results showed that interactive effect of NO and H2 S can considerably improve plant resistance against Cd toxicity by reducing oxidative stress and uptake of Cd in plants as well as by enhancing antioxidative defence system and uptake of some essential mineral nutrients.


Assuntos
Antioxidantes/fisiologia , Cádmio/toxicidade , Sulfeto de Hidrogênio/farmacologia , Óxido Nítrico/farmacologia , Estresse Oxidativo , Triticum/efeitos dos fármacos , Clorofila A/análise , Peróxido de Hidrogênio/análise , Malondialdeído/análise , Triticum/fisiologia
15.
Phytopathology ; 110(2): 297-308, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31483224

RESUMO

The reduction-oxidation (redox) environment of the phytobiome (i.e., the plant-microbe interface) can strongly influence the outcome of the interaction between microbial pathogens, commensals, and their host. We describe a noninvasive method using a bacterial bioreporter that responds to reactive oxygen species and redox-active chemicals to compare microenvironments perceived by microbes during their initial encounter of the plant surface. A redox-sensitive variant of green fluorescent protein (roGFP2), responsive to changes in intracellular levels of reduced and oxidized glutathione, was expressed under the constitutive SP6 and fruR promoters in the epiphytic bacterium Pantoea eucalypti 299R (Pe299R/roGFP2). Analyses of Pe299R/roGFP2 cells by ratiometric fluorometry showed concentration-dependent responses to several redox active chemicals, including hydrogen peroxide (H2O2), dithiothreitol (DTT), and menadione. Changes in intracellular redox were detected within 5 min of addition of the chemical to Pe299R/roGFP2 cells, with approximate detection limits of 25 and 6 µM for oxidation by H2O2 and menadione, respectively, and 10 µM for reduction by DTT. Caffeic acid, chlorogenic acid, and ascorbic acid mitigated the H2O2-induced oxidation of the roGFP2 bioreporter. Aqueous washes of peach and rose flower petals from young blossoms created a lower redox state in the roGFP2 bioreporter than washes from fully mature blossoms. The bioreporter also detected differences in surface washes from peach fruit at different stages of maturity and between wounded and nonwounded sites. The Pe299R/roGFP2 reporter rapidly assesses differences in redox microenvironments and provides a noninvasive tool that may complement traditional redox-sensitive chromophores and chemical analyses of cell extracts.


Assuntos
Técnicas Biossensoriais , Monitoramento Ambiental , Pantoea , Plantas , Técnicas Biossensoriais/métodos , Monitoramento Ambiental/métodos , Expressão Gênica/efeitos dos fármacos , Glutationa/farmacologia , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Peróxido de Hidrogênio/análise , Oxirredução , Pantoea/genética , Pantoea/metabolismo , Plantas/microbiologia , Espécies Reativas de Oxigênio/análise , Propriedades de Superfície , Vitamina K 3/análise
16.
Bioelectrochemistry ; 132: 107419, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31837615

RESUMO

Improved electron transfer properties and catalytic activity of manganese oxide (MnOx) was demonstrated following its electrochemical deposition on a deoxyribonucleic acid (DNA) modified glassy carbon electrode. The MnOx showed different morphologies, electrocatalytic properties and electrochemical kinetics. Scanning electron microscopy showed that electrodeposition of MnOx on a bare glassy carbon electrode led to the formation of irregular-shapes while a nanowire cluster (NWC) was formed on a GCE/DNA due to the DNA serving as a template. Electrochemical impedance spectroscopy (EIS) revealed lower charge transfer resistance of the MnOxNWC compared with MnOx. A new mechanism is presented for the electrodeposition of MnOx on the surface of a GC/DNA electrode. An electrochemical biosensor was fabricated based on depositing MnOx onto a glassy carbon /DNA electrode (GCE/DNA/MnOxNWC) and was used to detect hydrogen peroxide (H2O2). The MnOx nanowire cluster and DNA exhibited significant electrocatalytic activity for simultaneous electrocatalytic oxidation at two oxidation potentials (0.6 V and 0.98 V vs Ag/AgCl) and one reduction potential (-0.5 V vs Ag/AgCl) for H2O2 at pH 6.0. A new mechanism for the detection of H2O2 is presented. Excellent electrocatalytic activity, stability and facility for simultaneous detection of H2O2 at different of applied potentials are proposed advantages of the proposed electrochemical biosensor.


Assuntos
DNA/química , Peróxido de Hidrogênio/análise , Compostos de Manganês/química , Nanofios/química , Óxidos/química , Moldes Genéticos , Reprodutibilidade dos Testes
17.
Chemosphere ; 241: 125006, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31590016

RESUMO

The use of ornamental plant will increase with the improvement in living standards in green and blue-green infrastructure of urban settings. Nicotiana alata is an ornamental plant, frequently grown as a model plant for horticulture, medicine, and scientific research studies throughout the world. Despite its popularity, little is known about the response of N. alata against heavy metals (HMs). This work is based on the hydroponic study to identify the impacts of selected HMs (Cd, Cr, Cu, Ni and Pb) on N. alata, at 0, 50 and 100 µM concentration, with the co-application of EDTA, at 0 and 2.5 mM in hydroponics system. The HMs uptake was found to be dose dependent, with significant higher uptake at 100 µM of respective HM. Highest cumulative uptake (mg kg-1 of HMs in root, shoot, and leaf dried weight) noted were 767.50 ±â€¯50.83, 862.30 ±â€¯23.83, 271.29 ±â€¯18.68, 1117.49 ±â€¯46.10 and 2166.81 ±â€¯102.09, for Cd, Cr, Cu, Ni, and Pb at 100 µM, respectively. It was identified that EDTA co-application with HMs resulted in boosted HMs uptake, with cumulative uptake percentage increment of 41.62, 54.67, 53.98, 34.48 and 19.92% for 100 µM of Cd, Cr, Cu, Ni, and Pb, respectively. Higher uptake led to negative impact on plant physiology, photosynthetic pigments, and higher lipid peroxidation, H2O2 contents, and electrolyte leakage that increased the stress. Higher HMs uptake induced higher antioxidant enzymatic response. It is recommended to incorporate appropriate soil modification to grow N. alata in sustainable infrastructures.


Assuntos
Ácido Edético/farmacologia , Metais Pesados/farmacocinética , Poluentes do Solo/farmacocinética , Tabaco/crescimento & desenvolvimento , Tabaco/metabolismo , Peróxido de Hidrogênio/análise , Metais Pesados/análise , Oxirredutases/análise , Folhas de Planta/metabolismo , Raízes de Plantas/metabolismo , Poluentes do Solo/análise
18.
Nat Biomed Eng ; 4(2): 159-171, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31659307

RESUMO

Mechanical mismatches between implanted electronics and biological tissues can lead to inaccurate readings and long-term tissue damage. Here, we show that functionalized multi-walled carbon nanotubes twisted into helical fibre bundles that mimic the hierarchical structure of muscle can monitor multiple disease biomarkers in vivo. The flexible fibre bundles are injectable, have a low bending stiffness and display ultralow stress under compression. As proof-of-concept evidence of the sensing capabilities of these fibre bundles, we show that the fibre bundles enable the spatially resolved and real-time monitoring of H2O2 when implanted in tumours in mice, and that they can be integrated with a wireless transmission system on an adhesive skin patch to monitor calcium ions and glucose in the venous blood of cats for 28 d. The versatility of the helical fibre bundles as chemically functionalized electrochemical sensors makes them suitable for multiple sensing applications in biomedicine and healthcare.


Assuntos
Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/métodos , Diabetes Mellitus Tipo 1/metabolismo , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Nanotubos de Carbono , Neoplasias/metabolismo , Animais , Materiais Biocompatíveis , Biomarcadores/metabolismo , Biomarcadores Tumorais/metabolismo , Gatos , Diabetes Mellitus Tipo 1/diagnóstico , Feminino , Peróxido de Hidrogênio/análise , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Monitorização Fisiológica , Nanotubos de Carbono/ultraestrutura , Neoplasias/diagnóstico
19.
Environ Pollut ; 256: 113272, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31672353

RESUMO

Cadmium (Cd) pollution in mangrove wetlands has received increasing attention as urbanization expands rapidly. As a dominant mangrove species, Kandelia obovata is highly tolerant to Cd toxicity. Plant hormones and superoxide dismutase (SODs) play critical roles in the response to heavy metal stress in K. obovata roots. Although theirs important influence have been reported, the regulation mechanism between SODs and plant hormones in Cd detoxification by K. obovata roots remains limited. Here, we investigated relationships among SOD, plant hormones, and Cd tolerance in K. obovata roots exposed to Cd. We found that Cd was retained in the epidermis and exodermis of roots, and the epidermis and exodermis had highest hydrogen peroxide (H2O2) content and SOD activity. Similarly, SOD isozymes also exhibited distinct activity in the different parts of root. Overexpressed KoCSD3 and KoFSD2 individually in Nicotiana benthamiana revealed that different SOD members contributed to H2O2 content regulation by promote the activity of downstream antioxidant enzymes under Cd treatment. In addition, assays on the effects of hormones showed that increased endogenous indole-3-acetic acid (IAA) was observed in the cortex and stele, whereas the abscisic acid (ABA) content was enhanced in the epidermis and exodermis in roots during Cd treatment. The results of exogenous hormones treatment indicated that KoFSD2 upregulated under ABA and IAA treatment, but KoCSD3 only induced by ABA stimulation. Taken together, our results reveal the relationship between SODs and plant hormones, which expands the knowledge base regarding KoSODs response to plant hormones and mediating H2O2 concentration under Cd stress.


Assuntos
Cádmio/toxicidade , Peróxido de Hidrogênio/análise , Reguladores de Crescimento de Planta/metabolismo , Rhizophoraceae/efeitos dos fármacos , Superóxido Dismutase/metabolismo , Poluentes Químicos da Água/toxicidade , Adaptação Fisiológica/efeitos dos fármacos , Cádmio/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/enzimologia , Rhizophoraceae/enzimologia , Superóxido Dismutase/genética , Poluentes Químicos da Água/metabolismo , Áreas Alagadas
20.
ACS Appl Mater Interfaces ; 12(2): 1973-1987, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31846292

RESUMO

Nanomagnet-silica shell (Fe3O4@SiO2) decorated with Au@Pd nanoparticles (NPs) were synthesized successfully. The characterization of Fe3O4@SiO2-NH2-Au@PdNPs was achieved using several spectroscopic and microscopic techniques. The quantitative surface analysis was confirmed using X-ray photoelectron spectroscopy. The Fe3O4@SiO2-NH2-Au@Pd0.30NPs exhibited excellent peroxidase-like activity by effectively catalyzing the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of H2O2. The absorption peaks at 370 and 652 nm confirmed the peroxidase-like activity of the Fe3O4@SiO2-NH2-Au@Pd0.30NPs. The Michaelis-Menten constant (Km) of 0.350 and 0.090 mM showed strong affinity toward H2O2 and TMB at Fe3O4@SiO2-NH2-Au@Pd0.30NPs. The mechanism of the peroxidase-like activity was found to proceed via an electron transfer process. A simple colorimetric sensor based on glucose oxidase and Fe3O4@SiO2-NH2-Au@Pd0.30NPs showed excellent selectivity and sensitivity towards the detection of glucose. The fabricated glucose biosensor exhibited a wide linear response toward glucose from 0.010 to 60.0 µM with an limit of detection of 60.0 nM and limit of quantification of 200 nM. The colorimetric biosensor based on Fe3O4@SiO2-NH2-Au@Pd0.30NPs as a peroxidase mimic was also successfully applied for the determination of glucose concentrations in serum samples. The synthesized Fe3O4@SiO2-NH2-Au@Pd0.30NPs nanozymes exhibited excellent potential as an alternative to horseradish peroxidase for low-cost glucose monitoring.


Assuntos
Colorimetria/métodos , Glucose/análise , Ouro/química , Nanopartículas de Magnetita/química , Paládio/química , Peroxidases/metabolismo , Dióxido de Silício/química , Animais , Benzidinas/análise , Técnicas Biossensoriais , Glicemia/análise , Bovinos , Difusão Dinâmica da Luz , Peróxido de Hidrogênio/análise , Concentração de Íons de Hidrogênio , Cinética , Nanopartículas de Magnetita/ultraestrutura , Tamanho da Partícula , Espectroscopia Fotoeletrônica , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta , Temperatura
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