Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 269
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Insect Sci ; 2020 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-32166878

RESUMO

Spodoptera litura is a destructive agricultural pest in tropical and subtropical areas. Understanding the molecular mechanisms of S. litura adaptation to its preferred host plants may help identify target genes useful for pest control. We used high-throughput sequencing to characterize the expression patterns of mRNAs and microRNAs (miRNAs) in the midgut of S. litura fed on Brassica juncea for 6 h and 48 h. A total of 108 known and 134 novel miRNAs were identified, 29 miRNAs and 237 mRNAs were differentially expressed at 6 h of B. juncea feeding, 26 miRNAs and 433 mRNAs were differentially expressed at 48 h. For the mRNAs, the up-regulated genes were mostly enriched in detoxification enzymes (cytochrome P450, esterase, glutathione S-transferase, UDP-glucuronosyl transferase), while the down-regulated genes were mostly enriched in proteinases and immune related genes. Furthermore, most detoxification enzymes begin to up-regulated at 6 h, while most digestion and immune related gene begin to up or down-regulated at 48 h. 18 and 37 differently expressed transcription factors were identified at 6 h and 48 h, which may regulate the functional genes. We acquired 136 and 41 miRNA vs mRNA pairs at 6 h and 48 h, respectively. Some down-regulated and up-regulated miRNAs were predicted to targeting detoxification enzymes and proteinases, respectively. RT-qPCR of 9 randomly selected miRNAs and 28 genes confirmed the results of RNA-seq. This analyses of miRNA and mRNA transcriptomes provided useful information about the molecular mechanisms of S. litura response to B. juncea. This article is protected by copyright. All rights reserved.

2.
Org Lett ; 2020 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-32186385

RESUMO

Reported herein is the hydride transfer initiated redox-neutral cascade cyclizations of aurones, providing a variety of [6,5] spiro-heterocycles in satisfactory yields and good diastereoselectivities.

3.
Mikrochim Acta ; 187(4): 240, 2020 03 20.
Artigo em Inglês | MEDLINE | ID: mdl-32198661

RESUMO

A fluorescence resonance energy transfer (FRET)-based in situ fluorescence signal amplification strategy is described for the determination of tyrosinase (TYR). In this assay, a dual-templated copper nanocluster (CuNCs) stabilized by bovine serum albumin (BSA) and glycylglycine (Gly-Gly) was used as an energy donor. Metyrosine was employed as a TYR substrate because its enzyme catalytic product (methyldopa) was able to function as a monomer molecule to form fluorescent polymethyldopa (PMeDP) with the assistance of BSA/Gly-Gly CuNCs. In this process, PMeDP can combine with BSA/Gly-Gly CuNCs without extra modification and then acts as an energy receptor, which leads to a remarkable FRET from BSA/Gly-Gly CuNCs to PMeDP. Interestingly, the fluorescence intensity of PMeDP was strengthened greatly in the FRET-based sensor compared to the separate excitation, which provided good sensitivity for TYR sensing. Illuminated under a UV light source, the fluorescence signal change is observed from dark violet to bright green. Therefore, the present sensing system affords a reliable ratiometric assay for TYR determination. Also, the ratio of fluorescence intensity between PMeDP (λem at 505 nm, F505) and BSA/Gly-Gly CuNCs (λem at 415 nm, F415) was used for quantitative determination of TYR. The sensing system was easily operated in aqueous media with an exciting detection limit of 44.0 U L-1. This sensing strategy has been applied to the screening of inhibitors. Graphical abstract Schematic representation of the strategy for the determination of tyrosinase.

4.
J Cancer Res Clin Oncol ; 146(4): 821-841, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32103339

RESUMO

PURPOSE: Lung cancer has the highest morbidity and mortality among all cancer types. Reliable prognostic biomarkers are needed to identify high-risk patients apart from TNM system for precision medicine. The present study is designed to identify robust prognostic biomarkers in lung adenocarcinoma (LUAD) based on integration of multiple GEO datasets, The Cancer Genome Atlas (TCGA) database and Clinical Proteomic Tumor Analysis Consortium (CPTAC) database. METHODS: Four LUAD GEO datasets (GSE10072, GSE2514, GSE43458, and GSE32863) and TCGA database were implemented to analyze the differently expressed genes (DEGs). Gene ontology, KEGG pathway, and protein-protein interaction network (PPI) were conducted based on the above DEGs. Hub genes were selected based on connectivity degree in the PPI network. Expression analysis and Kaplan-Meier survival analysis were conducted in CPTAC lung adenocarcinomas cohort. Kaplan-Meier survival analysis and Cox proportional hazards regression were performed on these hub genes using TCGA and our own cohort. RESULTS: A total of 430 shared genes in all five datasets were identified as DEGs. Based on their PPI network, nine hub genes were selected and all of them were significantly associated with overall survival using GEPIA analysis. Two hub genes, TOP2A and UBE2C, were further combined and showed poorer prognosis in both TCGA dataset and our validated cohort. Analysis in CPTAC revealed that TOP2A and UBE2C were significantly highly expressed in tumor sample. Multivariable analysis suggested TOP2A and UBE2C as independent prognostic factors in LUAD. CONCLUSION: Using data mining approach, we identified TOP2A and UBE2C as two robust prognostic factors in LUAD. We also demonstrated the TOP2A/UBE2C co-expression status in LUAD, and TOP2A/UBE2C co-expression correlated with poorer prognosis. More in-depth research is needed for transforming this result into clinical setting.

5.
DNA Cell Biol ; 2020 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-32096653

RESUMO

Lung adenocarcinoma (LUAD) accounts for an increasing proportion of non-small-cell lung cancer and an increasing number of cancer-related deaths worldwide. However, few biomarkers are available for prognosis and patient stratification. In all eight datasets from the Oncomine and The Cancer Genome Atlas (TCGA) LUAD cohorts, solute carrier family 2 member 1 (SLC2A1) was significantly more highly expressed in LUAD tissue than in normal lung tissue. High SLC2A1 expression was also significantly (p < 0.05) associated with a poor prognosis in stage I, II, and III subgroups using the Kaplan-Meier plotter. In the National Cancer Center of China (NCC) cohort, SLC2A1 expression correlated significantly (p < 0.05) with several parameters, including sex, smoking history, tumor size, tumor differentiation, T stage, N stage, and pathologic TNM stage. Moreover, multivariate Cox regression indicated SLC2A1 to be an independent prognostic factor (p < 0.05) in both TCGA and NCC cohorts. Eleven hallmark pathways were significantly enriched (p < 0.01, false discovery rate <0.25) in the high-SLC2A1 expression group. SLC2A1 is a promising biomarker that can be used to predict the prognosis of LUAD.

6.
Bioresour Technol ; 300: 122670, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31901512

RESUMO

Ammonia (NH3) is the predominant harmful odor emitted from sludge aerobic composting plants, however, this NH3 could be recycled and used as energy or nitrogen fertilizer. Therefore, the aim of this study was to use molecular imprinting technology to prepare an adsorbent that could separate NH3 from mixed gases. An NH3 molecular imprinted polymer (NH3-MIP) was prepared by precipitation polymerization and optimal synthesis was determined by testing several different ratios of reaction components. NH3 adsorption capacity of the optimal NH3-MIP was 1.62 times that of non-imprinted material. NH3 separation factors increased from 154 (dimethyl sulfides) and 217 (dimethyl disulfides) for non-imprinted material, to 213 (dimethyl sulfides) and 302 (dimethyl disulfides) for the NH3-MIP. The adsorption mechanism was identified as physical adsorption and hydrogen bonding between H-O on the -COOH in NH3-MIP and the nitrogen in NH3. Effective desorption at 150 °C with vacuum maintained over 95% of the NH3 adsorption capacity.


Assuntos
Compostagem , Impressão Molecular , Adsorção , Amônia , Esgotos
7.
Chemosphere ; 242: 125235, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31698209

RESUMO

A core-shell structured zero-valent iron@carbon (ZVI@C) nanocompoiste was designed to improve the electron utilization of ZVI in the Cr(VI) reduction. The porosity of carbon layer in ZVI@C was optimized for improving the efficiency of electron utilization of ZVI in the Cr(VI) reduction process. The porous structure of carbon layer was controllably synthesized by adjusting the carbon source and the ratio of C/Fe in the precursor. The glucose was suggested as the optimal carbon source, and a high specific surface area (37.067 m2/g) was reached for the prepared ZVI@C when the ratio of C/Fe was controlled at 20. These ZVI@C performed well on Cr(VI) reduction, e.g. a complete reduction of Cr(VI) (2 mg/L) to Cr(III) within 10 min. The removal capacity (800 mg/g) exceeded previously recorded ZVI based adsorbents. The pH and initial Cr(VI) concentration were demonstrated as the key factors for the efficient electron utilization of ZVI. Furthermore, the efficiency of electron utilization of the ZVI increased up to 80% when the concentration of Cr(VI) was 2000 mg/L and the pH was controlled at 3, which was much higher than 8% of the naked ZVI.


Assuntos
Carbono , Cromo/química , Elétrons , Ferro/química , Nanopartículas/química , Concentração de Íons de Hidrogênio , Oxirredução
8.
Anal Chem ; 92(1): 1236-1244, 2020 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-31779312

RESUMO

In recent years, inorganic biomimetic nanozymes that mimic the activity of natural biological enzymes have attracted extensive research interest, and some mimic enzymes have been successfully applied in the fields of biosensing, catalysis, and oncotherapy. Herein, we report the preparation and mechanism study of a novel nanocomposite, Cu2+-modified hexagonal boron nitride nanosheets-supported subnanometer gold nanoparticles (Au NPs/Cu2+-BNNS). Interestingly, our investigation reveals that Cu2+-BNNS exhibits strong peroxidase mimetic nanoenzyme activity, while Au NPs/Cu2+-BNNS exhibits excellent oxidase-like activity, that is, it can catalyze the oxidation reaction of the substrate in the absence of an oxidant such as H2O2. For example, Au NPs/Cu2+-BNNS can efficiently and selectively oxidize 3,3',5,5'-tetramethylbenzidine (TMB) and 3,3'-dimethylbiphenyl-4,4'-diamine (OT) coloration without the presence of horseradish peroxidase (HRP) and H2O2. It is worthy to note that AuNPs/Cu2+-BNNS-induced TMB coloration only takes 4 min to reach the platform, while the conventional HRP-H2O2 system takes more than 30 min to reach the platform. Further mechanism study shows that the zeta potential, oxidation potential, and steric hindrance of the oxidative chromogenic substrate determine the selectivity of oxidation coloration, while the oxidase-like properties of Au NPs/Cu2+-BNNS are derived from reactive oxygen species generated by the adsorbed oxygen, and Cu2+ ion can synergistically promote the oxidation process. Compared with conventional biological enzymes, Au NPs/Cu2+-BNNS has the advantages of being HRP free and H2O2 free, having high efficiency, low cost, and good stability, and is successfully demonstrated for the detection of carcinoembryonic antigen (a universal cancer biomarker) and H2S (the third gaseous signal molecule).

9.
Food Chem ; 307: 125528, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31648181

RESUMO

Simple, rapid, convenient, and economical surface enhanced Raman scattering (SERS) substrate is developed for on-site evaluation of Aflatoxin B1 (AFB1) in food matrix using handheld Raman Spectrometer. Self-assembly of gold nanobipyramids (Au NBPs) into the nanoholes of anodic aluminum oxide (AAO) template/pattern using 'drop-dry' approach provides a reliable pathway for the rapid fabrication of highly active and uniform SERS substrate. It shows enhanced and reproducible SERS signals towards the probe molecule, 4-aminothiophenol (4-ATP) with a relative standard deviation (RSD) of less than 10% and an average enhancement factor (EF) of 1 × 108. For practical application, the proposed method is demonstrated for the detection of aflatoxin B1 (AFB1) in peanut extracts. The results show that the AFB1 in peanut extracts can be identified within 1 min, with a limit of detection of 0.5 µg/L. Compared with conventional ELISA based AFB1 analysis, our method is much more efficient (1 min versus >30 min).


Assuntos
Aflatoxina B1/análise , Arachis/química , Nanoestruturas/química , Extratos Vegetais/química , Análise Espectral Raman/métodos , Óxido de Alumínio/química , Arachis/metabolismo , Ouro/química , Limite de Detecção
10.
Clin Nutr ; 2019 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-31882231

RESUMO

BACKGROUND: The effects of low-protein diet (LPD) on kidney function and nutrition in nephropathy are so far unclear. OBJECTIVE: To investigate the effect of LPD on kidney function and nutrition. DATA SOURCES: PubMed, Embase and Cochrane library up to January 2019 and references of retrieved relevant articles. RESULT: Twenty-nine studies with 1784 individuals in the LPD arm and 1782 individuals in the normal protein diet were identified. Compared with normal protein diet, LPD significantly reduced BUN (WMD -20.756 mg/dl; 95% CI: -33.969 to -7.544 mg/dl; P = 0.002), UREA (WMD -1.400 g/24 h; 95% CI: -1.713 to -1.088 mmol/L; P < 0.001), proteinuria (WMD -0.416 g/24 h; 95% CI: -0.715 to -0.117 g/24 h; P = 0.006), body weight (WMD -2.757 kg; 95% CI: -3.890 to 1.623 kg; P < 0.001) and BMI (WMD -0.646 kg/m2; 95% CI: -1.068 to -0.223 kg/m2; P = 0.003). Dose-response analysis showed that reduction of protein intake by 0.1 g/kg/d was associated with a 0.68009 kg, 0.08771 kg/m2, 0.27147 g/L and 0.00309 g/24 hS reduction in body weight, BMI, ALB and Proteinuria, associated with a 0.135289 ml/min/1.73 m2 increase in GFR. The effects of LPD were more obvious on aged, obesity, moderate or severe renal impairment and DN patients. CONCLUSION: Low-protein diet was significantly associated with improvement of nephropathy, but LPD increases the risk of malnutrition such as BMI. The present meta-analysis provides evidence that LPD was associated with malnutrition, and high-quality RCTs with multi-center and large simple-size should be performed to confirm the present findings.

11.
Org Lett ; 21(22): 8904-8908, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31697087

RESUMO

Described herein is an unprecedented N-alkylation-initiated redox-neutral [5 + 2] annulation of 3-alkylindoles with o-aminobenzaldehydes via a cascade N-alkylation/dehydration/[1,5]-hydride transfer/Friedel-Crafts alkylation sequence. A series of indole-1,2-fused 1,4-benzodiazepines are facilely constructed in moderate to good yields in one step. This protocol features excellent regioselectivity, metal-free conditions, high step economy, and wide substrate scope.

12.
J Thorac Dis ; 11(10): 4282-4291, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31737313

RESUMO

Background: Lung cancer is one of the most common malignant tumors in the world and mainly occurs in elderly patients, but rarely in young patients. The purpose of this retrospective study was to examine the clinicopathological features and prognosis of lung cancer patients aged 30 years and younger. Methods: Patients aged 30 years and younger with lung cancer admitted to our center from November 2013 to October 2018 were retrospectively identified. Data included sex, age, smoking history, family history of cancer, high resolution computed tomography results, size and location of tumors, histology of tumors, lymph node status, stage of tumors, treatment methods and prognosis of patients. Results: The patient group included more females (56.3%) than males (43.7%) among lung cancer patients aged 30 and younger. Some patients had a history of tobacco inhalation and family cancer (17.5% and 22.3%, respectively). The most common tumors were in the left lower lobe (27.2%). Nearly half (49.5%) of the patients had pathological adenocarcinomas and 59.3% of the patients were showed early clinical stage and had no lymph node metastasis. All patients received surgical treatment; 47.1% received lobectomy and only 17.9% received adjuvant therapy such as radiotherapy, chemotherapy or targeted therapy after operation. Only seven (7.4%) of the successful follow-up patients died. Local recurrence occurred in two cases and distant metastasis in six cases. Conclusions: The main clinicopathological type of lung cancer in young lung cancer patients aged 30 years and younger is adenocarcinoma, and most cases were at the early stage. Surgical treatment based on lobectomy is still the main treatment method and the prognosis of these patients is very good. Early screening of lung cancer should be actively promoted for young people.

13.
Anal Chem ; 91(24): 15915-15921, 2019 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-31755262

RESUMO

The instability and insolubility of perovskite quantum dots in aqueous solution prohibit applications in polar solvents. As a highly toxic gas pollutant and also an endogenous gaseous signaling molecule existing in a variety of physiological processes, hydrogen sulfide (H2S), with high selectivity and high specificity, detection is of great significance. In this study, a simple device has been designed to separate H2S from aqueous solution and CsPbBr3 quantum dots (CsPbBr3 QDs) have been used as the detection probe to develop a novel fluorescent sensor for rapid H2S detection. The addition of hydrogen sulfide to the phosphoric acid solution results in the escape of H2S from the aqueous sample and hence it passing into the n-hexane solution containing CsPbBr3 QDs, resulting in the quenching of the fluorescence of CsPbBr3 QDs. The fluorescence intensity of the system has a linear relationship with the concentration of H2S in the range of 0-100 µM with the detection limit of 0.18 µM. The proposed system has been applied to detection of H2S in rat brain microdialysate with satisfying results. The potential mechanism regarding the quenching of fluorescence from CsPbBr3 QDs by H2S has been studied as well.

14.
Analyst ; 145(1): 132-138, 2019 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-31746827

RESUMO

This study reports a surface-enhanced electrochemiluminescence (SEECL) sensor for the ultrasensitive detection of prostate-specific antigen (PSA) in human serum. First, we prepared the Au-SiO2 core-shell nanocomposites doped with Ru(bpy)32+ (Au@SiO2-Ru) as the ECL signal generation and amplification element of the SEECL sensor. Ru(bpy)32+ could emit ECL under the excitation of an electrochemical reaction, and generate the local surface plasmon resonance (LSPR) electromagnetic field from the gold nanoparticle (AuNP) core. The produced LSPR then effectively enhanced the ECL signals. This sensing strategy was utilized for the detection of PSA, which can be absorbed on the electrode surface by the reaction between PSA and monoclonal antibodies. When polyclonal antibody-modified Au@SiO2-Ru was added, the PSA-double-antibody sandwich structure was formed on the electrode surface and thus, the Au@SiO2-Ru were quantitatively immobilized on the electrode surface. The results show that this kind of SEECL sensor has good selectivity toward PSA. Notably, the minimum detection concentration reached 7 × 10-7 ng mL-1 under the optimum experimental conditions, which is much better than most of the previously reported approaches for the detection of PSA in serum.

15.
Anal Chem ; 91(22): 14751-14756, 2019 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-31651147

RESUMO

Ribonuclease A (RNase A) is increasingly considered as a biomarker for tumor diagnosis, and it is of great significance to develop an ultrasensitive, cost-effective assay for RNase A detection. Electrochemiluminescence (ECL) technology has distinctive advantages in the development of biosensors for diverse targets. However, most of the ECL biosensors require the complex process of electrode modification, which is laborious and time consuming. In this work, an immobilization-free homogeneous ECL assay was developed for the highly sensitive detection of RNase A activity for the first time. On the basis of the fact that RNase A can specifically hydrolyze RNA at the site of ribonucleotide uracil (rU), a rU-containing chimeric DNA probe is designed and labeled with Ru(bpy)32+ (act as ECL indicator). The chimeric DNA probe hardly diffuses to the surface of negatively charged indium tin oxide (ITO) electrode due to the strong electrostatic repulsion between the negatively charged DNA and ITO electrode, resulting in a weak ECL signal detected. When the RNase A is present, the chimeric DNA probe is hydrolyzed into small fragments, which contains little negative charge and can diffuse easily to the ITO electrode surface due to the decreased electrostatic repulsion. In this case, an enhanced ECL signal can be detected. Under the optimal conditions, there is a linear relationship between the ECL signal and the concentration of RNase A in the range of 0.001-0.10 ng/mL, and the detection limit is 0.2 pg/mL. In addition, the proposed ECL sensing system is also applied to detect the RNase A inhibitor, taking As3+ as an example. The proposed homogeneous ECL sensing system provides a new approach for the highly sensitive and convenient detection of RNase A as well as other ribonucleases only by redesigning a responding chimeric DNA probe.

16.
Inorg Chem ; 58(21): 14842-14852, 2019 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-31621303

RESUMO

Mononuclear nonheme manganese complexes are highly efficient catalysts in the catalytic oxidation of hydrocarbons by hydrogen peroxide in the presence of carboxylic acids. Although high-valent Mn(V)-oxo complexes have been proposed as the active oxidants that afford high regio-, stereo-, and enantioselectivities in the catalytic oxidation reactions, the importance of the spin state (e.g., S = 0 or 1) of the proposed Mn(V)-oxo species is an area that requires further study. In the present study, we have theoretically demonstrated that a mononuclear nonheme Mn(V)-oxo species with an S = 1 ground spin state is the active oxidant that effects the stereo- and enantioselective alkane hydroxylation reaction; it is noted that synthetic octahedral Mn(V)-oxo complexes, characterized spectroscopically and/or structurally, possess an S = 0 spin state and are sluggish oxidants. In an experimental approach, we have investigated the catalytic hydroxylation of alkanes by a mononuclear nonheme Mn(II) complex, [(S-PMB)MnII]2+, and H2O2 in the presence of carboxylic acids; alcohol is the major product with high stereo- and enantioselectivities. A synthetic Mn(IV)-oxo complex, [(S-PMB)MnIV(O)]2+, is inactive in C-H bond activation reactions, ruling out the Mn(IV)-oxo species as an active oxidant. DFT calculations have shown that a Mn(V)-oxo species with an S = 1 spin state, [(S-PMB)MnV(O)(OAc)]2+, is highly reactive and capable of oxygenating the C-H bond via oxygen rebound mechanism; we propose that the triplet spin state of the Mn(V)-oxo species results from the consequence of breaking the equatorial symmetry due to the binding of an equatorial oxygen from an acetate ligand. Thus, the present study reports that, different from the previously reported S = 0 Mn(V)-oxo species, Mn(V)-oxo species with a triplet ground spin state are highly reactive oxidants that are responsible for the regio-, stereo-, and enantioselectivities in the catalytic hydroxylation of alkanes by mononuclear nonheme manganese complexes and terminal oxidants.

17.
Chem Commun (Camb) ; 55(86): 12980-12983, 2019 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-31603440

RESUMO

Nuclear factor kappa B p50 (NF-κB p50) induces various biological processes. In this study, a highly selective and sensitive electrochemiluminescence (ECL) biosensor for the detection of NF-κB p50 has been developed, which combines the high selectivity of the proximity hybridization assay (PHA) with the high efficiency of the hybridization chain reaction (HCR).


Assuntos
Técnicas Biossensoriais/métodos , Subunidade p50 de NF-kappa B/análise , DNA/química , Técnicas Eletroquímicas , Eletrodos , Humanos , Medições Luminescentes , Técnicas de Amplificação de Ácido Nucleico , Hibridização de Ácido Nucleico
18.
ACS Sens ; 4(9): 2465-2470, 2019 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-31525917

RESUMO

Lead ions (Pb2+) cause harm to human health. Therefore, the development of fast, effective, and convenient sensors for Pb2+ monitoring has received great attention. In this study, a portable method has been proposed for Pb2+ detection using normal electronic balance as a readout. Magnetic bead-catalytic strand is hybridized with platinum nanoparticles (Pt NPs) functioned substrate strand (Pt-Sub) to form double-stranded DNA first. In the presence of Pb2+, the DNAzyme is activated and cleaved at the ribo-adenosine site of the substrate strand and hence causes Pt NPs to be released into the supernatant, which can be easily separated from the Pt-Sub by a magnet. The separated Pt NPs can effectively catalyze the decomposition of H2O2 to produce O2. In a sealed bottle, the pressure inside the bottle is increased by the generation of oxygen so that the water is discharged from the drainage device, and the weight of the water can be easily and precisely measured by a normal electronic balance. The weighting water has a linear relationship with the concentration of Pb2+ in the range of 2.5-100 nM and the detection limit of 0.83 nM (S/N = 3). The proposed method has been applied to detect Pb2+ in water with satisfactory results. Because the electronic balance is one of the most commonly used analytical tools for the laboratory, it is very practical and convenient without the need for expensive instruments and complicated data processing.

19.
Int J Biol Macromol ; 140: 206-215, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31415856

RESUMO

Tetrastigma hemsleyanum Diels et Gilg (THDG) is used as a Chinese traditional anti-inflammatory medicine for about thousands of years. In this work, Tetrastigma hemsleyanum Diels et Gilg's polysaccharide (TP) can inhibit E. coli's growth in initial dosing period. Compared with the antibacterial effect of Achyranthe's polysaccharide (AP) from their metabolic profile, it's obviously that their metabolic sites for E. coli were inconsistent. Moreover, TP could not only increase the level of fructose-6-phosphate (F6P), decrease the level of fructose-1,6-diphosphate (FBP), but also charge the amount of the two differential metabolic with the change of the concentration and the dosing time. Actually, F6P could transform into FBP by catalyze of 6-phosphofructokinase-1(6-PFK-1), which is an important process in glycolysis. Furthermore, FBP was considered have positively correlated with E. coli's growth rate. Therefore, TP can inhibit the E. coli's proliferation by interfering with the process for glycolysis and gluconeogenesis. Based on the experimental result, we proposed a new mouthwash method to evaluate the anti-bacterial activity. Compared with AP, TP can inhibit the E. coli's growth within 2 h with a low concentration (0.5%) and a short dosing time (5 min). This study extends the applications of THDG and establishes a new assessment method for the pharmacology activity of Chinese herbal medicine.

20.
Anal Chem ; 91(18): 11821-11826, 2019 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-31436088

RESUMO

The development of simple but sensitive methods for hyaluronidase (HAase) detection has been paid a great deal of attention because HAase is a potential cancer marker. In this work, a novel system coupled with a controlled release system has been designed for HAase determination without complex analytical instruments and skilled technicians. Pt@SiO2 nanoparticles (NPs), which can catalyze the breakdown of H2O2 into O2 and H2O, was embedded in the hydrogel constructed by polyethylenimine (PEI) and hyaluronic acid (HA). In the presence of HAase, the hydrogel was broken down as HAase can catalyze the degradation of HA and hence the Pt@SiO2 NPs in the hydrogel was released. The released Pt@SiO2 NPs mixed with H2O2 solution in a drainage device, and then O2 was generated due to the decomposition of H2O2, resulting in an enhancement of pressure in the drainage device because of the low solubility of O2. A certain amount of H2O overflowed from the drainage device because the difference of the pressure between the inner and outer of the drainage device. The overflowed H2O was collected by a tube, and its amount was easily measured by an electronic balance. The weight of the H2O has a linear relationship with the HAase concentration in the range of 1-60 U/mL (120 min enzymatic hydrolysis time) and 0.2-10 U/mL (240 min enzymatic hydrolysis time). The developed system has been applied to detect the activity of HAase in urine samples with satisfied results.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA