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1.
Talanta ; 237: 122954, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34736679

RESUMO

Herein, a simple microfluidic paper-based analytical device (µPAD) by using platinum nanoparticles (Pt NPs) as highly active peroxidase mimic for simultaneous determination of glucose and uric acid was fabricated. The µPAD consisted of one sample transportation layer, four paper-based detection chips, and two layers of hydrophobic polyethylene terephthalate (PET) films. The four detection chips were immobilized with various chromogenic reagents, Pt NPs, and specific oxidase (glucose oxidase or uricase). H2O2 generated by specific enzymatic reactions could oxidize co-immobilized chromogenic reagents to produce colored products by using Pt NPs as efficient catalyst. The multi-layered structure of µPAD could effectively improve the color uniformity and color intensity. Total color intensity from each two detection chips modified with distinct chromogenic reagents were used for quantitative analysis of glucose and uric acid, respectively, resulting in significantly improved sensitivity. The linear range for glucose and uric acid detection was 0.01-5.0 mM and 0.01-2.5 mM, respectively. Satisfied results were obtained for glucose and uric acid detection in real serum samples. An easy-to-use smartphone APP was developed for convenient and intelligent detection. The developed µPAD integrated with smartphone as detector holds great applicability for simple and portable on-site analysis.


Assuntos
Nanopartículas Metálicas , Técnicas Analíticas Microfluídicas , Colorimetria , Glucose , Peróxido de Hidrogênio , Microfluídica , Papel , Peroxidase , Peroxidases , Platina , Smartphone , Ácido Úrico
2.
Bioresour Technol ; 343: 126138, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34678456

RESUMO

Herein, it was unearthed that manganese peroxidase (MnP) from Phanerochaete chrysosporium, a lignin-degrading enzyme, is capable of not only directly decomposing cellulosic components but also boosting cellulase activity. MnP decomposes various cellulosic substrates (carboxymethyl cellulose, cellobiose [CMC], and Avicel®) and produces reducing sugars rather than oxidized sugars such as lactone and ketoaldolase. MnP with MnII in acetate buffer evolves the MnIII-acetate complex functioning as a strong oxidant, and the non-specificity of MnIII-acetate enables cellulose-decomposition. The catalytic mechanism was proposed by analyzing catalytic products derived from MnP-treated cellopentaose. Notably, MnP also boosts cellulase activity on CMC and Avicel®, even considering the cellulolytic activity of MnP itself. To the best of the authors' knowledge, this is the first report demonstrating a previously unknown fungal MnP activity in cellulose-decomposition in addition to a known delignification activity. Consequently, the results provide a promising insight for further investigation of the versatility of lignin-degrading biocatalysts.


Assuntos
Celulase , Phanerochaete , Lignina , Peroxidases
3.
Food Chem ; 366: 130560, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34284183

RESUMO

The colorimetric method can determine the initial results even by the naked eyes, but its main challenge for antibiotics detection in food at present is the relatively low sensitivity. Herein, an ultrasensitive colorimetric biosensor based on G-quadruplex DNAzyme was firstly proposed for the rapid detection of trace tetracycline antibiotics like tetracycline, oxytetracycline, chlortetracycline and doxycycline. DNAzyme composed of hemin and G-quadruplex has peroxidase-like activity, and tetracyclines can combine with hemin to form a stable complex and reduce catalytic activity, making the color of solution changes from yellow to green. The limits of detection (LOD) of the proposed colorimetric biosensor for tetracyclines is determined as low as 3.1 nM, which is lower than most of the other colorimetric methods for antibiotics detection. Moreover, the average recovery range of tetracyclines in actual samples is from 89% to 99%, indicating that such strategy may has bright application prospects for tetracyclines detection in foods.


Assuntos
Técnicas Biossensoriais , DNA Catalítico , Tetraciclinas/análise , Antibacterianos , Colorimetria , Quadruplex G , Hemina , Peroxidase , Peroxidases
4.
Spectrochim Acta A Mol Biomol Spectrosc ; 265: 120348, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34507032

RESUMO

A label-free sensing strategy based on the enzyme-mimicking property of Glutathione-Ag nanoparticles (GSH-AgNPs) was demonstrated for colorimetric detection of vitamin B1 (VB1). Firstly, obvious blue color accompanied with an absorption peak at 652 nm was observed due to the high peroxidase-like activity of GSH-AgNPs towards 3,3',5,5'-tetramethylbenzidine (TMB). Then, in the presence of VB1, the mimetic activity of GSH-AgNPs could be strongly restrained, evidenced as a promiment colorimetric change to colorless, which can be used to achieve the visualization detection VB1. Linear relationship between absorbance response and VB1 concentration from 0 to 0.2 µM were obtained. The detection limit was calculated as low as 40 nM. The inhibition reasons were thoroughly discussed. Considering the advantages of rapid response, easy procedure and high selectivity, the proposed method possesses potential application in environment and biological analysis for VB1 detection.


Assuntos
Colorimetria , Nanopartículas Metálicas , Glutationa , Peroxidase , Peroxidases , Prata , Tiamina
5.
Spectrochim Acta A Mol Biomol Spectrosc ; 266: 120467, 2022 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-34637988

RESUMO

A novel Au NPs/GeO2 nanozymes are developed as Surface-Enhanced Raman Scattering (SERS) substrates with the promising prospect for detection ChI. Herein, it is discovered that both Au NPs and GeO2 nanozymes have peroxidase-like activity, catalyzing colorless 3,3',5,5'-tetramethylbenzidine (TMB) to produce blue TMBox. Interestingly, compared with single Au NPs or GeO2 nanozymes, the Au NPs/GeO2 nanozymes show stronger peroxidase-like activity, and significantly ameliorated SERS signal of TMBox. The mentioned two enhancements are ascribed to a positive synergistic function of Au NPs/GeO2 nanozymes. Surprisingly, choline iodide (ChI) can inhibit the positive synergy in Au NPs/GeO2 nanozymes, and slow down the reaction of TMB-H2O2-Au NPs/GeO2 system. On this foundation, a new Au NPs/GeO2 SERS technique with high sensitivity, label-free detection method of choline iodide (ChI) is established, suggesting that Au NPs/GeO2 nanozymes have the potential application of water environment.


Assuntos
Ouro , Nanopartículas Metálicas , Colina , Peróxido de Hidrogênio , Iodetos , Peroxidase , Peroxidases , Análise Espectral Raman
6.
J Colloid Interface Sci ; 607(Pt 1): 470-478, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34509729

RESUMO

Effective electronic interactions between molecular catalysts and supports are critical for heterogeneous enzyme mimics, yet they are frequently neglected in most catalyst designs. Taking the enzyme mimics of hemin immobilized on graphdiyne (Hemin-GDY) as an example, we explicate for the first time the underlying role of GDY as a co-catalyst. Based on the robust conjugation between GDY and hemin, the delocalized π-electrons in GDY act as a ligand for Fe ions so that the orbital interactions including electron transport from GDY â†’ Fe can induce the formation of an electron-rich Fe center and an electron-deficient π-electron conjugated system. This mechanism was validated by electron paramagnetic resonance (EPR), Raman spectroscopy, and DFT calculations. Moreover, both EPR spetra and Lineweaver-Burk plots revealed that Hemin-GDY could efficiently catalyze the decomposition of hydrogen peroxide (H2O2) to produce hydroxyl radical (•OH) and superoxide anion (O2•-) by a ping-pong type catalytic mechanism, and particularly, the catalytic activity was increased by 2.3-fold comparing to that of hemin immobilized on graphene (Hemin-GR). In addition, Hemin-GDY with the exceptional activity and stability was demonstrated for efficient catalytic degradation of organic pollutants under acidic conditions. Collectively, this work provides a theoretical basis for the design of GDY supported catalysts and renders great promises of the GDY based enzyme mimics.


Assuntos
Grafite , Biomimética , Hemina , Peróxido de Hidrogênio , Peroxidase , Peroxidases
7.
Anal Chim Acta ; 1187: 339171, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34753561

RESUMO

Nanozyme-mediated 3,3',5,5'-tetramethylbenzidine (TMB) - H2O2 systems have spawned the establishment of multiple colorimetric sensing platforms that are effective but sometimes subject to low sensitivity. Taking temperature as the output signal, photothermal effects lead to new strategies for sensitive detection. In this paper, a colorimetric and photothermal dual-mode immunoassay for diethylstilbestrol (DES) was constructed. It is based on the oxidation reaction of TMB catalyzed by black phosphorus-gold nanoparticle (BP/Au) nanohybrids, and the kinetics as well as catalytic mechanism of the nanohybrids were investigated in detail for the first time. Herein, the nanohybrids playcatalytic and photothermal dual roles. Moreover, the one-electron oxidation product of TMB (oxidized TMB) not only acts as chromogenic agent but also an excellent NIR laser-driven photothermal agent. The temperature (ΔT/°C) was gauged by a portable digital thermometer. Through an indirect competition strategy, a simple, sensitive, and economic immunosensor was proposed. Higher DES content in the sample correlated with less BP/Au nanohybrids conjugated to the surface of ELISA microplate, a weaker color change, and a lower temperature variation when exposed to laser irradiation. This method was applied for DES determination in real samples with gratifying recovery rates, showing great promise in food safety inspection applications.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Colorimetria , Dietilestilbestrol , Ouro , Peróxido de Hidrogênio , Imunoensaio , Peroxidase , Peroxidases , Fósforo
8.
Anal Chim Acta ; 1186: 339126, 2021 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-34756257

RESUMO

CuxO nanorods with excellent NADH peroxidase mimics were synthesized by a simple hydrothermal method. The catalytic oxidation of NADH to NAD cofactor strictly follows the enzymatic kinetics with high catalytic rate and strong affinity. The catalytic mechanism of CuxO NRs was that in the presence of hydrogen peroxide, the catalytic oxidizing NADH to NAD + involving with O2.-.anion production, making it realistic to mutually convert between coenzymes. Considering that the mutual transformation of NADH/NAD cofactors plays an important role in biological function, combination of CuxO NRs with alcohol dehydrogenase, a highly selective method for fluorimetric detection of ethanol was established. The as-proposed sensing platform is capable of dectecting alcohol with the limit of detection of 26.7 µM (S/N = 3) and applied in practical sample with satisfied accuracy and recovery. The as-developed regenerable NADH peroxidase mimics would also cast lights in biocatalysis, synthetic biology and bioenergy.


Assuntos
Etanol , Nanotubos , Fluorometria , Peroxidases
9.
Enzyme Microb Technol ; 151: 109917, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34649688

RESUMO

Lignin is a major byproduct of pulp and paper industries, which is resistant to depolymerization due to its heterogeneous structure. The enzymes peroxidases can be utilized as potent bio-catalysts to degrade lignin. In the current study, an Efeb gene of 1251bp encoding DyP-type peroxidase from Bacillus sp. strain BL5 (DyPBL5) was amplified, cloned into a pET-28a (+) vector and expressed in Escherichia coli BL21 (DE3) cells. A 46 kDa protein of DyPBL5 was purified through ion-exchange chromatography. Purified DyPBL5 was active at wide temperature (25-50 °C) and pH (3.0-8.0) range with optimum activity at 35 °C and pH 5.0. Effects of different chemicals on DyPBL5 were determined. The enzyme activity was strongly inhibited by SDS, DDT and ß-mercaptoethanol, whereas stimulated in the presence of organic solvents such as methanol and ethanol. The kinetic parameters were determined and Km, Vmax and Kcat values were 1.06 mM, 519.75 µmol/min/mg and 395 S̶ 1, respectively. Docking of DyPBL5 with ABTS revealed that, Asn 244, Arg 339, Asp 383 and Thr 389 are putative amino acids, taking part in the oxidation of ABTS. The recombinant DyPBL5 resulted in the reduction of lignin contents up to 26.04 %. The SEM and FT-IR analysis of test samples gave some indications about degradation of lignin by DyPBL5. Various low molecular weight lignin degradation products were detected by analyzing the samples through gas chromatography mass spectrometry. High catalytic efficiency and lignin degradation rate make DyPBL5 an ideal bio-catalyst for remediation of lignin-contaminated sites.


Assuntos
Bacillus , Lignina , Bacillus/genética , Clonagem Molecular , Peroxidases/genética , Espectroscopia de Infravermelho com Transformada de Fourier
10.
Int J Mol Sci ; 22(19)2021 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-34638559

RESUMO

Although peroxisomes play an essential role in viral pathogenesis, and viruses are known to change peroxisome morphology, the role of genotype in the peroxisomal response to viruses remains poorly understood. Here, we analyzed the impact of wheat streak mosaic virus (WSMV) on the peroxisome proliferation in the context of pathogen response, redox homeostasis, and yield in two wheat cultivars, Patras and Pamir, in the field trials. We observed greater virus content and yield losses in Pamir than in Patras. Leaf chlorophyll and protein content measured at the beginning of flowering were also more sensitive to WSMV infection in Pamir. Patras responded to the WSMV infection by transcriptional up-regulation of the peroxisome fission genes PEROXIN 11C (PEX11C), DYNAMIN RELATED PROTEIN 5B (DRP5B), and FISSION1A (FIS1A), greater peroxisome abundance, and activation of pathogenesis-related proteins chitinase, and ß-1,3-glucanase. Oppositely, in Pamir, WMSV infection suppressed transcription of peroxisome biogenesis genes and activity of chitinase and ß-1,3-glucanase, and did not affect peroxisome abundance. Activity of ROS scavenging enzymes was higher in Patras than in Pamir. Thus, the impact of WMSV on peroxisome proliferation is genotype-specific and peroxisome abundance can be used as a proxy for the magnitude of plant immune response.


Assuntos
Resistência à Doença/imunologia , Peroxissomos/metabolismo , Doenças das Plantas/imunologia , Doenças das Plantas/microbiologia , Potyviridae , Triticum/imunologia , Triticum/virologia , Quitinases/metabolismo , Clorofila/metabolismo , Glucana 1,3-beta-Glucosidase/metabolismo , Oxirredução , Peroxidases/metabolismo , Peroxissomos/genética , Peroxissomos/virologia , Fenótipo , Folhas de Planta/imunologia , Folhas de Planta/virologia , Espécies Reativas de Oxigênio/metabolismo
11.
Analyst ; 146(21): 6470-6473, 2021 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-34609387

RESUMO

A novel and low-cost DNAzyme, Ni/Fe layered double hydroxide (LDH) nanosheet/G-quadruplex (without hemin) with enhanced peroxidase-mimic activity was designed. The catalytic mechanism was investigated. The detection of Cu(II) in actual serum samples could be realized sensitively via this efficient DNAzyme-based method.


Assuntos
Técnicas Biossensoriais , DNA Catalítico , Quadruplex G , DNA Catalítico/metabolismo , Hemina , Hidróxidos , Peroxidase , Peroxidases
12.
An Acad Bras Cienc ; 93(suppl 3): e20210296, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34586183

RESUMO

Fungi are excellent producers of extracellular enzymes. Therefore, the present study aimed to investigate the screening of marine fungi, which are laccase and manganese peroxidase potential producers, in solid fermentation for future applications in bioremediation processes of contaminated sites. For this purpose, two-level factorial planning was adopted, using time (6 and 15 days) and the absence or presence of oil (0 and 1%) as factors. The semi-quantitative evaluation was carried out by calculating radial growth, enzyme activity and enzyme index by measuring phenol red or syringaldazine oxidation halo. The results showed that all the studied strains showed a positive result for manganese peroxidase production, with an enzymatic activity in solid medium less than 0.61, indicating a strongly positive activity. Through the enzyme index, the study also showed prominence for Penicillium sp. strains, with values > 2. The enzyme index increase in oil presence and the inexpressive use of the genera studied for ligninolytic enzymes production from crude oil demonstrated these data importance for fermentative processes optimization. Considering the ability of these strains to develop into recalcitrant compounds and the potential for manganese peroxidase production, they are indicated for exploitation in various bioremediation technologies, as well as other biotechnological applications.


Assuntos
Lacase , Peroxidases , Biodegradação Ambiental , Meios de Cultura , Fermentação , Fungos/metabolismo , Peroxidases/metabolismo
13.
Mater Sci Eng C Mater Biol Appl ; 129: 112404, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34579916

RESUMO

Herein a nano-scale bimetallic Fe/Eu-MOF with a regular octahedral structure was synthesized for the first time. The synthesized Fe/Eu-MOF has both peroxidase-like activity and fluorescence properties. Fe/Eu-MOF can catalyze H2O2 to oxidize the chromogenic substrate TMB to produce blue oxTMB, which has ultraviolet absorption at 652 nm. Unexpectedly, the generated oxTMB can effectively quench the fluorescence of the catalyst Fe/Eu-MOF at 450 nm. The quenching mechanism is mainly the internal filtration effect (IFE), accompanied by static quenching (SQE), Förster resonance energy transfer (FRET) and photoelectron transfer (PET). Fe/Eu-MOF has a high affinity for sodium pyrophosphate (PPi). PPi can be adsorbed to the surface of Fe/Eu-MOF, destroying the structure of Fe/Eu-MOF and inhibiting its catalytic activity, resulting in a decrease in UV absorbance and the decline of fluorescence quenching. In contrast, phosphoric acid (Pi) has almost no effect on the reaction system. Alkaline phosphatase (ALP) can catalyze the hydrolysis of PPi to Pi, thereby reducing the inhibitory effect of PPi. Based on this, we successfully constructed a dual-mode ALP sensor with high selectivity. The linear ranges based on the 652 nm absorption or the fluorescence detection are from 1 to 200 U/L, and the detection limits are 0.6 for the absorption method and 0.9 U/L for the fluorescence method, respectively.


Assuntos
Fosfatase Alcalina , Peroxidase , Corantes Fluorescentes , Peróxido de Hidrogênio , Peroxidases
14.
Chemistry ; 27(63): 15730-15736, 2021 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-34505733

RESUMO

The morphology of nanomaterials (geometric shape and dimension) play a significant role in its various physical and chemical properties. Thus, it is essential to link morphology with performance in specific applications. For this purpose, the morphology of copper metal-organic polyhedra (Cu-MOP) can be modulated through distinct assembly process, which facilitates the exploration of the relationship between morphology and catalytic performance. In this work, the assemblies of Cu-MOP with three different morphologies (nanorods, nanofibers and nanosheets) were facilely prepared by the variation of solvent mixture of N, N-dimethylformamide (DMF) and methanol, revealed the important role of the interaction between the surface group and the solvent on the morphology of these assemblies. Cu-MOP nanofibers exhibited the highest mimetic peroxidase enzyme activity over the Cu-MOP nanosheets and nanorods, which have been utilized in the detection of glucose. Cu-MOPs assemblies with tunable morphology accompanied with adjustable mimic peroxidase activity, had great potential applications in the field of bioanalytical chemistry and biomedicals.


Assuntos
Cobre , Peroxidase , Catálise , Oxirredução , Peroxidases
15.
Environ Pollut ; 290: 118022, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34492527

RESUMO

Volatile brominated compounds are important trace gases for stratospheric ozone chemistry. In this study, the spatial variations of dibromomethane (CH2Br2), bromodichloromethane (CHBrCl2), dibromochloromethane (CHBr2Cl) and bromoform (CHBr3) in the seawater and overlying atmosphere were measured in the Yellow Sea (YS) and the East China Sea (ECS) in winter. The air-sea fluxes of CH2Br2, CHBrCl2, CHBr2Cl and CHBr3 ranged from -11.46 to 25.33, -4.68 to 7.91, -8.60 to 4.08 and -88.57 to 8.84 nmol m-2·d-1, respectively. In order to understand the mechanism of halocarbons production, we measured bromoperoxidase (BrPO) activity (39.18-186.74 µU·L-1) in the YS and ECS for the first time using an aminophenyl fluorescein (APF) method and performed in-situ incubation experiments in BrPO-treated seawater. The production rates of CH2Br2, CHBrCl2, CHBr2Cl and CHBr3 ranged from 14.21 to 94.74, 0.00 to 19.74, 0.00 to 30.62 and 6.18-72.75 pmol L-1·h-1, respectively, in BrPO-treated seawater. There were significantly higher production rates in coastal waters compared with the open sea (P = 0.016) because of higher DOC levels near the coast. Moreover, the production rates of halocarbons increased with BrPO activity and H2O2 concentration. The results showed that enzyme-mediated reaction was an important source for the production of halocarbons in seawater. The present research is of great significance for understanding the production mechanisms of halocarbons in seawater and global oceanic halocarbons emissions.


Assuntos
Poluentes Atmosféricos , Monitoramento Ambiental , Poluentes Atmosféricos/análise , China , Peróxido de Hidrogênio , Oceanos e Mares , Peroxidases , Água do Mar
16.
Anal Chem ; 93(36): 12353-12359, 2021 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-34469123

RESUMO

Although single-atom catalysts with high enzyme-like activities have been found, the rational design of highly active peroxidase (POD)-like nanozymes is still a formidable challenge. Herein, highly active POD-like nanozymes were synthesized through loading Pt clusters on the Fe single-atom (FeSA-PtC) nanozymes. The POD-like activity of FeSA-PtC nanozymes is enhanced 4.5-fold and 7-fold, in comparison to that of FeSA and PtC nanozymes, respectively, which is attributed to the unexpected synergistic effect between Fe single atoms and Pt clusters. Based on the outstanding POD-like activity of FeSA-PtC nanozymes, a cascade signal amplification strategy was constructed by combining glucose oxidase for the colorimetric biosensing of prostate-specific antigens, exhibiting satisfactory sensitivity, high selectivity, a low detection limit of 1.8 pg/mL, and practical feasibility in serum sample detection. This work may serve as a tough foundation to guide the design of superior POD-like nanozymes and expand the application in biosensing.


Assuntos
Técnicas Biossensoriais , Colorimetria , Peróxido de Hidrogênio , Imunoensaio , Peroxidases
17.
Anal Chim Acta ; 1180: 338740, 2021 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-34538313

RESUMO

Total Antioxidant Capacity (TAC) Assay plays an important role in evaluating the quality of antioxidant food and monitoring the oxidative stress level of human body. It is mainly achieved by measuring the contents of antioxidants such as AA, L-Cys and GSH, while TAC can be detected by using peroxidase-like activity of artificial nanoenzyme materials. In this work, the N-Doped, defect-rich N-MoS2NFs nano-materials were used to build the nano enzyme, which has strong stability and high peroxidase-like activity. H2O2 was detected because it can be catalyzed to generate the intermediate ·OH and make TMB appears blue. However, when H2O2, AA, L-Cys and GSH coexist in solution, due to the oxidation resistance of AA, L-Cys and GSH, they can competitively react with ·OH in solution or reduce TMB in oxidation state (oxTMB), which reduces the characteristic absorption of oxTMB, indirectly achieves the purpose of detecting AA, L-Cys and GSH, and finally realizes the determination of TAC, even in actual serum and saliva samples. At the same time, the N-MoS2 NFs/NH2-MIL-53(Al)+OPD system is further constructed. Based on the fluorescence resonance energy transfer (FRET) between NH2-MIL-53(Al) and oxidized OPD (oxOPD), the purpose of detecting TAC by fluorescence method was realized.


Assuntos
Antioxidantes , Peroxidase , Colorimetria , Humanos , Peróxido de Hidrogênio , Molibdênio , Peroxidases
18.
Sensors (Basel) ; 21(16)2021 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-34450980

RESUMO

Copper (II) ions have been shown to greatly improve the chemical stability and peroxidase-like activity of gold nanoclusters (AuNCs). Since the affinity between Cu2+ and pyrophosphate (PPi) is higher than that between Cu2+ and AuNCs, the catalytic activity of AuNCs-Cu2+ decreases with the introduction of PPi. Based on this principle, a new colorimetric detection method of PPi with high sensitivity and selectivity was developed by using AuNCs-Cu2+ as a probe. Under optimized conditions, the detection limit of PPi was 0.49 nM with a linear range of 0.51 to 30,000 nM. The sensitivity of the method was three orders of magnitude higher than that of a fluorescence method using AuNCs-Cu2+ as the probe. Finally, the AuNCs-Cu2+ system was successfully applied to directly determine the concentration of PPi in human urine samples.


Assuntos
Ouro , Nanopartículas Metálicas , Colorimetria , Cobre , Difosfatos , Corantes Fluorescentes , Humanos , Limite de Detecção , Peroxidase , Peroxidases , Espectrometria de Fluorescência
19.
Biochim Biophys Acta Gene Regul Mech ; 1864(10): 194734, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34339889

RESUMO

Glutathione peroxidase 7 (GPx7) acts as an intracellular stress sensor/transmitter and plays an important role in adipocyte differentiation and the prevention of obesity related pathologies. For this reason, finding the regulatory mechanisms that control GPx7 expression is of great importance. As microRNAs (miRNAs) could participate in the regulation of GPx7 expression, we studied the inhibition of GPx7 expression by four selected miRNAs with relation to obesity and adipogenesis. The effect of the transfection of selected miRNAs mimics on GPx7 expression was tested in three cell models (HEK293, SW480, AT-MSC). The interaction of selected miRNAs with the 3'UTR of GPx7 was followed up on using a luciferase gene reporter assay. In addition, the levels of GPx7 and selected miRNAs in adipose tissue mesenchymal stem cells (AT-MSC) and mature adipocytes from four human donors were compared, with the changes in these levels during adipogenesis analyzed. Our results show for the first time that miR-137 and miR-29b bind to the 3'UTR region of GPx7 and inhibit the expression of this enzyme at the mRNA and protein level in all the human cells tested. However, no negative correlation between miR-137 nor miR-29b level and GPx7 was observed during adipogenesis. Despite the confirmed inhibition of GPx7 expression by miR-137 and miR-29b, the action of these two molecules in adipogenesis and mature adipocytes must be accompanied by other regulators.


Assuntos
Adipogenia/genética , Regulação Enzimológica da Expressão Gênica , MicroRNAs/metabolismo , Peroxidases/genética , Regiões 3' não Traduzidas , Adipócitos/metabolismo , Linhagem Celular Tumoral , Células Cultivadas , Feminino , Humanos , Pessoa de Meia-Idade , RNA Mensageiro/metabolismo , Células-Tronco/metabolismo
20.
Plant Physiol Biochem ; 167: 577-585, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34461554

RESUMO

Sweetpotato (Ipomoea batatas [L.] Lam) is a prospective food crop that ensures food and nutrition security under the dynamic changes in global climate. Peroxidase (POD) is a multifunctional enzyme involved in diverse plant physiological processes, including stress tolerance and cell wall lignification. Although various POD genes were cloned and functionally characterized in sweetpotato, the role of POD in lignification and low-temperature storage ability of sweetpotato tuberous roots is yet to be investigated. In this study, we isolated the cold-induced lignin forming peroxidase (IbLfp) gene of sweetpotato, and analyzed its physiological functions. IbLfp showed more predominant expression in fibrous roots than in other tissues. Moreover, IbLfp expression was up-regulated in leaves and roots under cold stress, and was altered by other abiotic stresses. Tuberous roots of transgenic sweetpotato lines overexpressing IbLfp (LP lines) showed improved tolerance to low temperature, with lower malondialdehyde and hydrogen peroxide contents than non-transgenic sweetpotato plants under cold stress. The enhanced cold tolerance of LP lines could be attributed to the increased basal activity of POD, which is involved in reactive oxygen species (ROS) scavenging. Moreover, greater accumulation of lignin could also contribute to the enhanced cold tolerance of LP lines, as lignin acts as a protective barrier against invading pathogens, which is a secondary symptom of chilling injury in sweetpotato. Overall, the results of this study enhance our understanding of the function of POD in low-temperature storage of sweetpotato tuberous roots.


Assuntos
Ipomoea batatas , Resposta ao Choque Frio , Regulação da Expressão Gênica de Plantas , Ipomoea batatas/genética , Peroxidases , Plantas Geneticamente Modificadas , Estudos Prospectivos , Temperatura
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