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1.
Zhongguo Zhong Yao Za Zhi ; 46(19): 4950-4958, 2021 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-34738389

RESUMO

In this study, the gene encoding the key enzyme 3-ketoacyl-CoA thiolase(KAT) in the fatty acid ß-oxidation pathway of Atractylodes lancea was cloned. Meanwhile, bioinformatics analysis, prokaryotic expression and gene expression analysis were carried out, which laid a foundation for the study of fatty acid ß-oxidation mechanism of A. lancea. The full-length sequence of the gene was cloned by RT-PCR with the specific primers designed according to the sequence information of KAT gene in the transcriptomic data of A. lancea and designated as AIKAT(GenBank accession number MW665111). The results showed that the open reading frame(ORF) of AIKAT was 1 323 bp, encoding 440 amino acid. The deduced protein had a theoretical molecular weight of 46 344.36 and an isoelectric point of 8.92. AIKAT was predicted to be a stable alkaline protein without transmembrane segment. The secondary structure of AIKAT was predicted to be mainly composed of α-helix. The tertiary structure of AIKAT protein was predicted by homology modeling method. Homologous alignment revealed that AIKAT shared high sequence identity with the KAT proteins(AaKAT2, CcKAT2, RgKAT and AtKAT, respectively) of Artemisia annua, Cynara cardunculus var. scolymus, Rehmannia glutinosa and Arabidopsis thaliana. The phylogenetic analysis showed that AIKAT clustered with CcKAT2, confirming the homology of 3-ketoacyl-CoA thiolase genes in Compositae. The prokaryotic expression vector pET-32 a-AIKAT was constructed and transformed into Escherichia coli BL21(DE3) for protein expression. The target protein was successfully expressed as a soluble protein of about 64 kDa. A real-time quantitative PCR analysis was performed to profile the AIKAT expression in different tissues of A. lancea. The results demonstrated that the expression level of AIKAT was the highest in rhizome, followed by that in leaves and stems. In this study, the full-length cDNA of AIKAT was cloned and expressed in E. coli BL21(DE3), and qRT-PCR showed the differential expression of this gene in different tissues, which laid a foundation for further research on the molecular mechanism of fatty acid ß-oxidation in A. lancea.


Assuntos
Atractylodes , Sequência de Aminoácidos , Atractylodes/genética , Clonagem Molecular , Coenzima A , Escherichia coli/genética , Filogenia
2.
Planta ; 255(1): 8, 2021 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-34845523

RESUMO

MAIN CONCLUSION: Two squalene synthase genes AlSQS1 and AlSQS2 were isolated from Atractylodes lancea and functionally characterized using in vitro enzymatic reactions. Atractylodes lancea is a traditional herb used for the treatment of rheumatic diseases, gastric disorders, and influenza. Its major active ingredients include sesquiterpenoids and triterpenes. Squalene synthase (SQS; EC 2.5.1.21) catalyzes the first enzymatic step in the central isoprenoid pathway towards sterol and triterpenoid biosynthesis. In this study, we aimed to investigate two SQSs from A. lancea using cloning and in vitro enzymatic characterization. Bioinformatics and phylogenetic analyses revealed that the AlSQSs exhibited high homology with other plant SQSs. Furthermore, AlSQS1 was observed to be localized in both the nucleus and cytoplasm, whereas AlSQS2 was localized in the cytoplasm and endoplasmic reticulum. To obtain soluble recombinant enzymes, AlSQS1 and AlSQS2 were successfully expressed as glutathione S-transferase (GST)-tagged fusion proteins in Escherichia coli Transetta (DE3). Approximately 68 kDa recombinant proteins were obtained using GST-tag affinity chromatography and Western blot analysis. Results of the in vitro enzymatic reactions established that both AlSQS1 and AlSQS2 were functional, which verifies their catalytic ability in converting two farnesyl pyrophosphates to squalene. The expression patterns of AlSQS and selected terpenoid genes were also investigated in two A. lancea chemotypes using available RNA sequencing data. AlSQS1 and AlSQS2, which showed relatively similar expression in the three tissues, were more highly expressed in the stems than in the leaves and rhizomes. Methyl jasmonate (MeJA) was used as an elicitor to analyze the expression profiles of AlSQSs. The results of qRT-PCR analysis revealed that the gene expression of AlSQS1 and AlSQS2 plummeted at lowest value at 12 h and reached its peak at 24 h. This study is the first report on the cloning, characterization, and expression of SQSs in A. lancea. Therefore, our findings contribute novel insights that may be useful for future studies regarding terpenoid biosynthesis in A. lancea.

3.
Opt Express ; 29(18): 29402-29411, 2021 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-34615050

RESUMO

Yttrium oxide (Y2O3) has garnered some attention in view of its potential to be integrated into a wide range of high-strength structural components, microelectronic and optoelectronic devices. However, the nonlinear optical research of this promising material has not been implemented yet. In this paper, not only the electronic band structures of Y2O3 are theoretically calculated but also the optical nonlinearity of Y2O3 is validated by using the fiber laser as a platform. Meanwhile, the influence of sample thickness on laser performance is further explored by using Y2O3 saturable absorbers with different thickness. Results indicate that Y2O3 not only has impressive optical nonlinearity but also is beneficial to the investigation of ultrafast photons by adjusting the thickness of Y2O3. Therefore, Y2O3 can be used as a potential saturable absorber candidate for in-depth research and application.

4.
Nanotechnology ; 32(50)2021 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-34479216

RESUMO

This article introduces an innovative technique for achieving a giant magnetoresistance (GMR) switch with an adjustable sensing field range. A spin-valve (SV) patterned into a strip shape is grown on a specific (110)-cut Pb(Mg1/3Nb2/3)0.7Ti0.3O3(PMN-PT) substrate. In the process of depositing films, a magnetic easy axis of the free layer in the SV is produced along the [001] direction (thex-axis) of the PMN-PT. This PMN-PT can produce a nonvolatile strain by using a positive voltage pulse. Accordingly, the magnetic moment of the free layer can be modulated to they-axis by the strain-mediated magnetoelectric coupling effect produced in the SV/PMN-PT heterostructure. Furthermore, a negative voltage pulse can release the strain and revert the magnetic moment to the initial [001] direction. The effective field along the [1-10] direction produced by the nonvolatile strain can modulate the easy axis of the free layer, changing it from thex-axis to they-axis. Therefore, large and small switching fields are achieved in a bipolar GMR switch. Furthermore, by applying positive and negative voltage pulses at appropriate moments, two asymmetrical switching field ranges are obtained. Thus, a GMR switch with four adjustable switching field ranges can be obtained. The proposed modulating model is flexible and can meet the requirements of specific and different application systems. The proposed design reveals a great potential for the application to the internet of things and the development of low-power and high-efficient magnetoresistive sensors.

5.
Adv Sci (Weinh) ; 8(20): e2102915, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34473424

RESUMO

Understanding the relationship between the electronic state of active sites and N2 reduction reaction (NRR) performance is essential to explore efficient electrocatalysts. Herein, atomically dispersed Fe and Mo sites are designed and achieved in the form of well-defined FeN4 and MoN4 coordination in polyphthalocyanine (PPc) organic framework to investigate the influence of the spin state of FeN4 on NRR behavior. The neighboring MoN4 can regulate the spin state of Fe center in FeN4 from high-spin (dxy 2 dyz 1 dxz 1 d z 2 1 d x 2 - y 2 1 ) to medium-spin (dxy 2 dyz 2 dxz 1 d z 2 1 ), where the empty d orbitals and separate d electron favor the overlap of Fe 3d with the N 2p orbitals, more effectively activating N≡N triple bond. Theoretical modeling suggests that the NRR preferably takes place on FeN4 instead of MoN4 , and the transition of Fe spin state significantly lowers the energy barrier of the potential determining step, which is conducive to the first hydrogenation of N2 . As a result, FeMoPPc with medium-spin FeN4 exhibits 2.0 and 9.0 times higher Faradaic efficiency and 2.0 and 17.2 times higher NH3 yields for NRR than FePPc with high-spin FeN4 and MoPPc with MoN4 , respectively. These new insights may open up opportunities for exploiting efficient NRR electrocatalysts by atomically regulating the spin state of metal centers.

6.
J Am Med Dir Assoc ; 2021 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-34389337

RESUMO

OBJECTIVES: To determine the sex-specific associations of handgrip strength (HGS) and asymmetry with incident multimorbidity and examine whether these relationships differ by sex. DESIGN: Prospective cohort study. SETTING AND PARTICIPANTS: Secondary analyses of data from the English Longitudinal Study of Ageing (ELSA, waves 2-8). The analytic sample included 3977 participants (51.4% female) aged ≥50 years who had data for HGS on both hands and were living without multimorbidity at baseline. MEASURES: HGS was assessed with a handheld dynamometer. Individuals in the lowest tertile of sex-specific age-adjusted HGS were defined as having low HGS. The largest HGS readings from the nondominant and dominant hand were used to calculate HGS ratio [nondominant HGS (kg)/dominant HGS (kg)]. Those with HGS ratio <0.90 or >1.10 had any HGS asymmetry. Further, those with HGS ratio <0.90 had dominant HGS asymmetry, whereas those with HGS ratio >1.10 had nondominant HGS asymmetry. Multimorbidity was defined as the coexistence of ≥2 chronic diseases. Cox proportional hazards regression models were conducted for analyses. RESULTS: Low HGS was associated with multimorbidity among older men [hazard ratio (HR) 1.20, 95% confidence interval (CI) 1.03-1.40] and women (HR 1.19, 95% CI 1.03-1.38). No significant effect modification by sex was observed (P-interaction = .71). HGS asymmetry increased the risk of multimorbidity in women only (HR 1.23, 95% CI 1.07-1.41). The relationship between HGS asymmetry and multimorbidity risk differed by sex (P-interaction = .01). Similarly, both dominant HGS asymmetry (HR 1.21, 95% CI 1.05-1.40) and nondominant HGS asymmetry (HR 1.32, 95% CI 1.03-1.68) were related to incident multimorbidity in women only. There was a significant interaction between dominant HGS asymmetry and sex (P-interaction = .02). CONCLUSIONS AND IMPLICATIONS: Examining HGS asymmetry in HGS test protocols can provide novel insights for the predictive power of HGS in the accumulation of diseases, particularly in women.

7.
Planta ; 254(2): 34, 2021 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-34291354

RESUMO

MAIN CONCLUSION: Comprehensive transcriptome analysis of different Platycodon grandiflorus tissues discovered genes related to triterpenoid saponin biosynthesis. Platycodon grandiflorus (Jacq.) A. DC. (P. grandiflorus), a traditional Chinese medicine, contains considerable triterpenoid saponins with broad pharmacological activities. Triterpenoid saponins are the major components of P. grandiflorus. Here, single-molecule real-time and next-generation sequencing technologies were combined to comprehensively analyse the transcriptome and identify genes involved in triterpenoid saponin biosynthesis in P. grandiflorus. We quantified four saponins in P. grandiflorus and found that their total content was highest in the roots and lowest in the stems and leaves. A total of 173,354 non-redundant transcripts were generated from the PacBio platform, and three full-length transcripts of ß-amyrin synthase, the key synthase of ß-amyrin, were identified. A total of 132,610 clean reads obtained from the DNBSEQ platform were utilised to explore key genes related to the triterpenoid saponin biosynthetic pathway in P. grandiflorus, and 96 differentially expressed genes were selected as candidates. The expression levels of these genes were verified by quantitative real-time PCR. Our reliable transcriptome data provide valuable information on the related biosynthesis pathway and may provide insights into the molecular mechanisms of triterpenoid saponin biosynthesis in P. grandiflorus.


Assuntos
Platycodon , Saponinas , Triterpenos , Perfilação da Expressão Gênica , Platycodon/genética , Transcriptoma
8.
Nano Lett ; 21(14): 6071-6079, 2021 07 28.
Artigo em Inglês | MEDLINE | ID: mdl-34269590

RESUMO

Streamlined architectures with a low fluid-resistance coefficient have been receiving great attention in various fields. However, it is still a great challenge to synthesize streamlined architecture with tunable surface curvature at the nanoscale. Herein, we report a facile interfacial dynamic migration strategy for the synthesis of streamlined mesoporous nanotadpoles with varied architectures. These tadpole-like nanoparticles possess a big streamlined head and a slender tail, which exhibit large inner cavities (75-170 nm), high surface areas (424-488 m2 g-1), and uniform mesopore sizes (2.4-3.2 nm). The head curvature of the streamlined mesoporous nanoparticles can be well-tuned from ∼2.96 × 10-2 to ∼5.56 × 10-2 nm-1, and the tail length can also be regulated from ∼30 to ∼650 nm. By selectively loading the Fe3O4 catalyst in the cavity of the streamlined silica nanotadpoles, the H2O2-driven mesoporous nanomotors were designed. The mesoporous nanomotors with optimized structural parameters exhibit outstanding directionality and a diffusion coefficient of 8.15 µm2 s-1.


Assuntos
Nanopartículas , Dióxido de Silício , Catálise , Peróxido de Hidrogênio , Porosidade
9.
Fitoterapia ; 153: 104988, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34246745

RESUMO

Orchidaceae, well known for its fascinating flowers, is one of the largest and most diverse families of flowering plants. There are many kinds of plants in this family; these are distributed practically globally and have high ornamental and medicinal values. Gastrodia elata Blume, a traditional Chinese medicinal herb, is a rootless and leafless achlorophyllous orchid. Phenolic compounds are considered to be the major bioactive constituents in G. elata, with antioxidant, antiangiogenic, neuroprotective, antidepressant, anxiolytic, and sedative activities. In this study, we determined the contents of six main phenolic components in tubers, stems and flowers from G. elata. Meanwhile, the transcriptomes of the tuber, stem and flower tissues of G. elata were obtained using the BGISEQ-500 platform. A total of 58.29 Gb of data and 113,067 unigenes were obtained, of which 74,820 unigenes were functionally annotated against seven public databases. Differentially expressed genes between tuber, stem and flower tissues were identified. A total of 76 DEGs encoding eight key enzymes were identified as candidate genes involved in the biosynthesis of phenolics in G. elata. For further validation, the expression levels of unigenes were measured using quantitative real-time PCR. Our results greatly enrich the transcriptomic data of G. elata and provide valuable information for the identification of candidate genes involved in the biosynthesis of secondary metabolites.


Assuntos
Gastrodia/genética , Genes de Plantas , Fenóis/metabolismo , Transcriptoma , Vias Biossintéticas/genética , Flores/genética , Estrutura Molecular , Caules de Planta/genética , Tubérculos/genética , Metabolismo Secundário/genética
10.
Ying Yong Sheng Tai Xue Bao ; 32(6): 2259-2266, 2021 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-34212632

RESUMO

Soil-plant system is the basic structural unit of the biosphere, with close mutual feedback between soil and plants. The degradation of soil exerts various abiotic stresses to plants, disturbs the physiological metabolism of plants, and inhibits nutrient acquisition. Earthworms are known as "ecosystem engineers", which can regulate soil physical-chemical-biological characteristics, improve the quality of the degraded soil (saline soil, heavy metals and organic pollutants contaminated soil), alleviate plants under stress, increase soil nutrient availability, promote plant growth. Furthermore, through the secretion of signal substances, earthworms could improve the resistance of plants. The ecological remediation effects of earthworms on soil-plant system are of great significance for improving environment of plant growth and maintaining the health and stability of soil.


Assuntos
Oligoquetos , Poluentes do Solo , Animais , Biodegradação Ambiental , Ecossistema , Solo , Poluentes do Solo/análise
11.
Arch Gerontol Geriatr ; 94: 104369, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33556636

RESUMO

OBJECTIVE: To explore the effect of sleep duration at baseline on the incident IADL disability among middle-aged and older Chinese, and test whether cognition mediates this causality. METHODS: Data were collected from wave 1 (2011-2012) to wave 3 (2015-2016) of the China Health and Retirement Longitudinal Study (CHARLS). Sleep duration was self-reported at baseline. Cognitive function, including episodic memory and mental intactness were measured via a questionnaire. IADL was assessed at baseline and follow-up. Baron and Kenny's causal steps and Karlson/Holm/Breen (KHB) method were conducted to examine the mediating effect. RESULTS: A total of 10,328 participants free of IADL disability at baseline were included in this study. Over 4 years of follow-up, 17.1% of participants developed IADL disability. Compared to 7-8 h sleep duration, both short sleep (OR=1.460; 95% CI: 1.261-1.690 for sleeping ≤5 h; OR= 1.189; 95% CI: 1.011-1.400 for sleeping 5-7 h) and long sleep (OR=1.703; 95% CI: 1.269-2.286 for sleeping >9 h) were linked with incident IADL disability. KHB method identified significant mediating effect of cognition on the relationship between extreme sleep durations (≤5 h or >9 h) and IADL disability and the proportional mediation through cognition was 21.32% and 21.06% for sleeping ≤5 h and >9 h, respectively. CONCLUSION: Both short (sleeping ≤5 h) and long sleep duration (sleeping >9 h) predicted incident IADL disability. Cognition partially mediated the effect of extreme sleep durations on IADL disability.


Assuntos
Atividades Cotidianas , Cognição , Idoso , China/epidemiologia , Avaliação da Deficiência , Humanos , Estudos Longitudinais , Pessoa de Meia-Idade , Sono
12.
J Pharm Anal ; 11(2): 129-137, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33520327

RESUMO

The outbreak and spread of novel coronavirus disease 2019 (COVID-19) with pandemic features, which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), have greatly threatened global public health. Given the perniciousness of COVID-19 pandemic, acquiring a deeper understanding of this viral illness is critical for the development of new vaccines and therapeutic options. In this review, we introduce the systematic evolution of coronaviruses and the structural characteristics of SARS-CoV-2. We also summarize the current diagnostic tools and therapeutic strategies for COVID-19.

13.
Pharm Biol ; 58(1): 157-164, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32037930

RESUMO

Context: Er Miao San (EMS) is a traditional Chinese medicine composed of Atractylodis Rhizoma and Phellodendri Cortex in a 1:1 weight ratio. EMS has been used to treat rheumatism in China for many years.Objective: To evaluate the anti-arthritic activity of EMS extract on adjuvant-induced arthritis (AA) in Sprague-Dawley rats and to clarify its mechanisms of action.Materials and methods: EMS (0.75, 1.5 and 3 g/kg, once daily) was orally administered from day 18 after immunization to day 31. The effects of EMS on AA rats were evaluated by histopathological examination, paw swelling and polyarthritis index. The proliferation of fibroblast-like synoviocyte (FLS) and T cells was detected by CCK-8. The percentages of Th17 cells and Treg cells in splenocytes were determined by flow cytometry. Levels of cytokines in serum were detected by ELISA.Results: EMS treatment significantly decreased the paw volume (from 1.20 to 0.81), polyarthritis index (from 9.56 to 4.46) and alleviated ankle joint histopathology in AA rats. EMS inhibited the proliferation of FLS and T cells. Furthermore, EMS treatment decreased Th17 cells (from 4.62 to 2.08%) and increased Treg cells (from 2.77 to 4.75%) in splenocytes. The levels of IL-17A, TNF-α and IL-6 were remarkably decreased in the serum of EMS-treated rats, whereas the levels of IL-10 and TGF-ß1 were significantly increased.Conclusions: EMS exhibits anti-arthritic activity in the AA model by regulating the balance of cytokines and the ratio of Th17 and Treg cells. These insights may provide an experimental basis for the clinical treatment of RA.


Assuntos
Antirreumáticos/farmacologia , Artrite Experimental/tratamento farmacológico , Medicamentos de Ervas Chinesas/farmacologia , Animais , Antirreumáticos/administração & dosagem , Artrite Experimental/patologia , Proliferação de Células/efeitos dos fármacos , Citocinas/sangue , Relação Dose-Resposta a Droga , Medicamentos de Ervas Chinesas/administração & dosagem , Adjuvante de Freund , Masculino , Ratos , Ratos Sprague-Dawley , Linfócitos T Reguladores/metabolismo , Células Th17/metabolismo
14.
PLoS One ; 15(2): e0227284, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32050262

RESUMO

Phytophthora blight caused by Phytophthora capsici is a devastating disease for melon plant. However, the underlying resistance mechanisms are still poorly understood. In this study, the transcriptome differences between the resistant ZQK9 and susceptible E31 at 0, 3, and 5 days post-inoculation (dpi) were identified by RNA-seq. A total of 1,195 and 6,595 differentially expressed genes (DEGs) were identified in ZQK9 and E31, respectively. P. capsici infection triggered massive transcript changes in the inoculated tissues. Genes related to plant defense responses were activated, which was reflected by a lot of up-regulated DEGs involved in pathogenesis-related (PR) genes, hormones biosynthesis and signal transduction, secondary metabolites biosynthesis and cell wall modification in resistant ZQK9. The dataset generated in this study may provide a basis for identifying candidate resistant genes in melon against P. capsici and lay a foundation for further research on the molecular mechanisms.


Assuntos
Cucurbitaceae/genética , Resistência à Doença/genética , Regulação da Expressão Gênica de Plantas/genética , Doenças das Plantas/genética , Proteínas de Plantas/genética , Transcriptoma/genética , Perfilação da Expressão Gênica/métodos , Phytophthora/crescimento & desenvolvimento
15.
Int J Pharm ; 577: 119046, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31982559

RESUMO

A rotigotine (ROT)-loaded polymer micelles thermosensitive gel (ROT-PM-TSG) delivery system was engineered to enhance the solubility of the drug, prolong the residence time, and increase the concentration of the drug in the brain tissue. First, ROT-loaded polymer micelles (ROT-PM) were tailored and optimized. The average particle size, encapsulation efficiency, and drug loading of the ROT-PM were (88.62 ± 1.47) nm, (93.5 ± 0.79) %, and (19.9 ± 0.60) %. The optimal ROT-PM-TSG formulation contained 22% P407 and 2% P188 with a gelation temperature of about 32.3 °C and a pH of 5.186. In vivo, the MRT of ROT-PM and ROT-PM-TSG nasal administration was 1.43 and 1.79 times extended than that of the intravenous. In comparison with the intravenous group, the distribution of ROT in olfactory bulb, cerebrum, cerebellum and striatum was 276.6%, 170.5%, 166.5% and 184.4%, respectively. In conclusion, the ROT-PM-TSG system has proven to be a potential application prospect as a ROT nose-to-brain delivery system.


Assuntos
Agonistas de Dopamina/administração & dosagem , Sistemas de Liberação de Medicamentos , Polímeros/química , Tetra-Hidronaftalenos/administração & dosagem , Tiofenos/administração & dosagem , Administração Intranasal , Animais , Encéfalo/metabolismo , Agonistas de Dopamina/farmacocinética , Portadores de Fármacos/química , Feminino , Hidrogéis , Masculino , Micelas , Tamanho da Partícula , Coelhos , Ratos , Ratos Sprague-Dawley , Solubilidade , Temperatura , Tetra-Hidronaftalenos/farmacocinética , Tiofenos/farmacocinética
16.
J Phys Condens Matter ; 32(23): 235802, 2020 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-31778978

RESUMO

A series of Ta/NiCo/Ta films was grown through DC-sputtering. During deposition, a constant magnetic field was applied along the substrate in different directions to induce different orientations of the easy axis. Three different magnitudes of external fields were applied in the angle-dependent anisotropic magnetoresistance (AMR) measurements of the samples. Through an effective analysis, the angle-direction extracted via the intersection of three angle-dependent AMR curves was confirmed as the easy axis. Compared to the normal methods applied to achieve the easy axis, the results are convincing. This new method provides an effective, convenient and low cost way of studying magnetic materials and devices.

17.
Ecotoxicol Environ Saf ; 189: 109996, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31785943

RESUMO

A large proportion (60-90%) of ingested tetracyclines are released to slurry, soils, surface waters and ground water, which has raised extensive concerns and may pose a risk to the soil ecosystem. A 56-day experiment was conducted to study the bioremediation by earthworms on soil microbial diversity and partial nitrification processes in oxytetracycline (OTC)-contaminated soil. The results showed that high OTC concentration significantly decreased the activity of soil bacteria, ammonia-oxidizing bacteria (AOB) and archaea (AOA). Earthworms were found to accelerate the degradation efficiency and rate of OTC, and its main metabolites were 4-epi-oxytetracycline (EOTC) and 2-acetyl-2-decarboxamido-oxytetracycline (ADOTC). Earthworms had an important role in the bioremediation of soil microbial diversity by degrading OTC and its metabolite (EOTC), especially in the high OTC condition. Additionally, the results indicated that the effects of earthworms on the degradation of OTC could remediate the abundances of 16S rRNA and AOB amoA genes and the NO3- content in both low and high OTC-contaminated soils. The structural equation model suggested that earthworms could remediate the microbial diversity, the abundances of 16s rRNA and AOB amoA genes by accelerating the degradation of OTC, which contributed to the bioremediation by earthworms on soil microbial diversity and partial nitrification processes in oxytetracycline-contaminated soil.


Assuntos
Biodegradação Ambiental , Oligoquetos/metabolismo , Oxitetraciclina/metabolismo , Microbiologia do Solo , Poluentes do Solo/metabolismo , Solo/química , Animais , Archaea/efeitos dos fármacos , Ecossistema , Nitrificação , Oxirredução , Oxitetraciclina/análise , RNA Ribossômico 16S/genética , Poluentes do Solo/análise
18.
Nanomaterials (Basel) ; 9(6)2019 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-31234413

RESUMO

A convenient bipolar-electrode (BPE) electrochemical method was engineered to produce molybdenum disulfide (MoS2) quantum dots (QDs) using pure phosphate buffer (PBS) as the electrolyte and the MoS2 powder as the precursor. Meanwhile, the corresponding by-product precipitate was studied, in which MoS2 nanosheets were observed. The BPE design would not be restricted by the shape and size of the MoS2 precursor. It could lead to the defect generation and 2H → 1T phase variation of the MoS2, resulting in the formation of nanosheets and finally the QDs. The as-prepared MoS2 QDs exhibited high photoluminescence (PL) quantum yield of 13.9% and average lateral size of 4.4 ± 0.2 nm, respectively. Their excellent PL property, low cytotoxicity, and good aqueous dispersion offer promising applicability in PL staining and cell imaging. Meanwhile, the as-obtained byproduct containing the nanosheets could be used as an effective electromagnetic wave (EMW) absorber. The minimum reflection loss (RL) value was -54.13 dB at the thickness of 3.3 mm. The corresponding bandwidth with efficient attenuation (<-10 dB) was up to 7.04 GHz (8.8-15.84 GHz). The as-obtained EMW performance was far superior over most previously reported MoS2-based nanomaterials.

19.
Talanta ; 195: 706-712, 2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-30625605

RESUMO

Organophosphorus pesticide (OP) residues in agricultural products, herbal medicines and environment have attracted increasing concerns because they cause high healthy risk. Herein, a tyrosinase-mediated photoinduced electron transfer system was constructed for OPs analysis by using dopamine-functionalized upconversion nanoparticles (UCNPs) as fluorescent (FL) sensors. Dopamine quinone was produced by tyrosinase-mediated oxidation of dopamine on the surface of UCNPs, which acted as electron accepter to quench the FL emission of UCNPs. The FL quenching was inhibited by OP since it inhibited the activity of tyrosinase. Chlorpyrifos was used as a model analyte to investigate the feasibility of the FL sensor for the analysis of OPs. Under the optimal conditions, chlorpyrifos can be analysed in a wide range of 1.0 ‒ 1000 ng mL-1, with a detection limit of 0.38 ng mL-1 (3σ). Some other groups pesticides, including organonitrogen pesticide, organochlorine pesticide and chloronicotinyl insecticide all showed negligible interference. The proposed sensor was successfully used to analyse chlorpyrifos spiked in Balloonflower and Angelica with acceptable recovery values of 95.4-120.0%, demonstrating its application potential for real samples. It exhibits some advantages like low cost, high sensitivity and free of autofluorescent interference and photobleaching.


Assuntos
Clorpirifos/análise , Dopamina/análogos & derivados , Corantes Fluorescentes/química , Inseticidas/análise , Metais Terras Raras/química , Nanopartículas/química , Angelica/química , Campanulaceae/química , Clorpirifos/química , Dopamina/química , Inseticidas/química , Monofenol Mono-Oxigenase/química
20.
J Mater Chem B ; 7(6): 897-902, 2019 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-32255094

RESUMO

The metal-induced FL quenching of two-dimensional material-derived quantum dots (2D-QDs) has been playing vital roles in optical sensing recently; however, the metal type and concentration are usually chosen arbitrarily based on the maximum FL decrease although several metals may offer similar FL quenching effects towards the same 2D-QDs. Thus, a rational strategy was urgently needed to discover more efficient metal-mediated FL system for further applications. Taking boron nitride QDs (BNQDs) as a promising 2D-QD model, it was discovered that both Fe3+ and Cu2+ could quench their FL, which could be further switched on and off upon the addition of pyrophosphate and alkaline phosphatase, respectively. By comparing the percentage of FL quenching and recovery of BNQDs, it was rationally calculated that 300 µM Fe3+-mediated FL quenching of BNQDs paved a more efficient way for the sensitive and selective assay of ALP. Quantitative measurement of the ALP activity can be achieved with a low limit of detection of 0.8 U L-1 (S/N ≥ 3) in a wide range between 2 and 200 U L-1. In addition, the aforementioned ensemble could be exploited to newly construct a 2D-QD-based "INH" logic gate. This approach possessed many superiorities i.e. low cost, simplicity, and high sensitivity.


Assuntos
Fosfatase Alcalina/análise , Compostos de Boro/química , Pontos Quânticos/química , Espectrometria de Fluorescência/métodos , Fosfatase Alcalina/metabolismo , Corantes Fluorescentes/química , Limite de Detecção
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