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1.
Yi Chuan ; 42(2): 153-160, 2020 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-32102772

RESUMO

Mosquito-borne diseases have become an important public health issue of global concern because of their high incidence and transmission rate. As a vector for mosquito-borne diseases, studying the interaction mechanism between mosquitoes and mosquito-borne viruses will help control mosquito-borne diseases. The impaired innate immunity and immune barriers evasion caused by mosquito-borne viruses in mosquitoes pose a potential risk for the persistent infection of the virus in mosquitoes and the outbreak of mosquito-borne diseases. The RNA interference (RNAi) pathway, as a powerful antiviral defense barrier in mosquitoes, can inhibit viral replication and transmission by producing a variety of small RNAs to degrade viral RNA. In this review, we summarize the related studies on the innate immune mechanism against mosquito- borne virus infection in mosquitoes about small interfering RNA (siRNA), microRNA (miRNA), and Piwi-interacting RNA (piRNA), aiming to provide a theoretical reference for the prevention and control of mosquito-borne diseases.


Assuntos
Culicidae/virologia , Interferência de RNA , Viroses , Animais , Culicidae/imunologia , Imunidade Inata , Mosquitos Vetores/imunologia , Mosquitos Vetores/virologia , RNA Interferente Pequeno , Viroses/prevenção & controle , Viroses/transmissão
2.
J Org Chem ; 85(2): 622-632, 2020 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-31799847

RESUMO

An efficient Pd-catalyzed arylation of alkylpyridine based on the pyridinium activation strategy has been developed for synthesis of mixed aryl alkylpyridines. It was found that (1) the N-methyl group in the pyridinium salts acted as a transient activator and could be automatically departed after the reaction, (2) CuBr was an indispensable additive for achieving the C6-selective arylation, (3) the α-branched alkyl chain on the alkylpyridine greatly increased the yield of the product. Deuterium labelling experiment revealed that in the case of the α-branched alkylpyridine, the presence of CuBr completely inhibited the H/D exchange at the benzylic position and thus enabled the selective arylation at the C6 position. This protocol demonstrates a broad substrate scope, and with respect to both the aryl iodides and the α-branched alkylpyridine, the desired mixed aryl alkylpyridines were obtained in generally good to excellent yields.

3.
J Org Chem ; 84(14): 9151-9160, 2019 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-31273988

RESUMO

A selective catalytic system for the dehydrogenation of primary alcohols to carboxylic acids using a facial ruthenium complex generated in situ from the [Ru(COD)Cl2]n and a hybrid N-heterocyclic carbene (NHC)-phosphine-phosphine ligand (CPP) has been first reported. The facial coordination model was unveiled by NMR analysis of the reaction mixture. Such a fac-ruthenium catalyst system exhibited high catalytic activity and stability, and a high turnover number of 20 000 could be achieved with catalyst loading as low as 0.002 mol %. The exceedingly high catalyst stability was tentatively attributed to both the anchoring role of NHC and the hemi-lability of phosphines. The catalytic system also features a wide substrate scope. In particular, the facial coordination of CPP ligands was found to be beneficial for sterically hindered alcohols, and ortho-substituted benzylic alcohols and bulky adamantanyl methanol as well as cholesterol were all found to be viable dehydrogenation substrates.

4.
J Org Chem ; 84(4): 2158-2168, 2019 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-30676029

RESUMO

Herein, an efficient and green method for the selective synthesis of tertiary amines has been developed that involves iridium-catalyzed alkylation of various primary amines with aromatic or aliphatic alcohols. Notably, the catalytic protocol enables this transformation in the absence of additional base and solvent. Furthermore, the alkylation of nitrobenzene with primary alcohol to tertiary amine has also been achieved by the same catalytic system. Deuterium-labeling experiments and a series of control experiments were conducted, and the results suggested that an intermolecular borrowing hydrogen pathway might exist in the alkylation process.

5.
Adv Mater ; 31(11): e1804769, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30680808

RESUMO

Oxygen evolution reaction (OER) is a pivotal reaction in many technologies for renewable energy, such as water splitting, metal-air batteries, and regenerative fuel cells. However, this reaction is known to be kinetically sluggish and proceeds at rather high overpotential due to the universal scaling relationship, namely, the adsorption energies of intermediates are linearly correlated and cannot be optimized simultaneously. Several approaches have been proposed to break the scaling relationship by introducing additional active sites; however, positive experimental results are still absent. Herein, a different solution is suggested on the basis of dynamic tridimensional adsorption of the OER intermediates at NiO/NiFe layered double hydroxide intersection, by which the adsorption energy of each intermediate can be adjusted independently, so as to bypass the scaling relationship and achieve high catalytic performance. Experimentally, the OER overpotential is reduced to ≈205 mV at current density of 30 mA cm-2 , which represents the best performance achieved by state-of-the-art OER catalysts.

6.
Int J Med Mushrooms ; 21(9): 851-864, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-32450025

RESUMO

Polysaccharides are some of the most important bioactive compounds in Lentinus edodes, but little attention has been devoted to the genetic basis of polysaccharide content. Here, the polysaccharide content of fruiting body, and 11 agronomic traits related to morphologic characteristics of fruiting body, yield and precocity of 50 L. edodes strains were screened and analyzed. Results showed that polysaccharide content in L. edodes fruiting bodies is a quantitative trait controlled by the polygenic system. Several wild strains possess desirable polysaccharide contents, exhibiting the potential to improve shiitake cultivars by introducing the promising alleles. There were no close correlations between polysaccharide content and the 11 agronomic traits related with fruiting body morphology, yield and precocity, suggesting that polysaccharide content and the development of fruiting bodies may genetically be controlled independently. Moreover, based on polysaccharide content and the 11 agronomic traits, grey relational analysis (GRA) was employed for a comprehensive strain evaluation by calculating grey relational grades. The results demonstrate that weighted relational grade analysis is effective in the comprehensive evaluation of L. edodes strains. The ranking of most cultivars was higher than that of wild strains. Cultivar ZP9 was the best strain, concerning its comprehensive phenotypic performance. Wild strain YS1 with the highest polysaccharide content (6.60%) also ranked in the top seven. In our study, we developed the first multiple-trait strategy for L. edodes strain evaluation. The step-by-step procedures of GRA described here provide an important reference for strain evaluation and selection of other edible mushrooms.

7.
J Org Chem ; 83(8): 4441-4454, 2018 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-29595260

RESUMO

The first Pd-catalyzed multicomponent reaction of aryl iodides, alkenyl bromides, and strained alkenes has been developed, which allowed us to synthesize a variety of multisubsituted olefins in yields of 45-96% with excellent stereoselectivity. The configuration of the product was controlled by the configuration of the alkenyl bromides. Moreover, this practical methodology employing readily available substrates was found to be tolerant to a wide range of functional groups. Fifty six examples of highly stereoselective tri- or tetrasubstituted olefins have been successfully synthesized via this methodology. Most of the synthesized tetrasubstituted olefins are good aggregation-induced emission (AIE) luminogens.

8.
Int J Mol Sci ; 18(5)2017 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-28481288

RESUMO

It is well-documented that CL316,243 (a ß3 agonist) or rosiglitazone (a PPARγ agonist) can induce white adipocyte populations to brown-like adipocytes, thus increasing energy consumption and combating obesity. However, whether there is a combined effect remains unknown. In the present study, stromal vascular cells of inguinal white adipose tissue (iWAT-SVCs for short) from mice were cultured and induced into browning by CL316,243, rosiglitazone, or both. Results showed that a combination of CL316,243 and rosiglitazone significantly upregulated the expression of the core thermogenic gene Ucp1 as well as genes related with mitochondrial function (Cidea, Cox5b, Cox7a1, Cox8b, and Cycs), compared with the treatment of CL316,243 or rosiglitazone alone. Moreover, co-treatment with rosiglitazone could reverse the downregulation of Adiponectin resulting from CL316,243 stimuli alone. Taken together, a combination of rosiglitazone and CL316,243 can produce an additive effect of promoting thermogenic gene expression and an improvement of insulin sensitivity in mouse iWAT-SVCs.


Assuntos
Adipócitos Marrons/metabolismo , Adipócitos Brancos/metabolismo , Adipogenia , Hipoglicemiantes/farmacologia , Mitocôndrias/metabolismo , Adipócitos Marrons/citologia , Adipócitos Marrons/efeitos dos fármacos , Adipócitos Brancos/citologia , Adipócitos Brancos/efeitos dos fármacos , Adiponectina/genética , Adiponectina/metabolismo , Animais , Células Cultivadas , Dioxóis/farmacologia , Camundongos , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Rosiglitazona , Células Estromais/citologia , Células Estromais/efeitos dos fármacos , Células Estromais/metabolismo , Tiazolidinedionas/farmacologia
9.
Small ; 13(16)2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-28195444

RESUMO

Manganese-based oxides have exhibited high promise as noncoinage alternatives to Pt/C for catalyzing oxygen reduction reaction (ORR) in basic solution and a mix of Mn3+/4+ valence is believed to be vital in achieving optimum ORR performance. Here, it is proposed that, distinct from the most studied perovskites and spinels, Mn-based mullites with equivalent molar ratio of Mn3+ and Mn4+ provide a unique platform to maximize the role of Mn valence in facile ORR kinetics by introducing modest content of oxygen deficiency, which is also beneficial to enhanced catalytic activity. Accordingly, amorphous mullite SmMn2 O5-δ nanoparticles with finely tuned concentration of oxygen vacancies are synthesized via a versatile top-down approach and the modest oxygen-defective sample with an Mn3+ /Mn4+ ratio of 1.78, i.e., Mn valence of 3.36 gives rise to a superior overall ORR activity among the highest reported for the family of Mn-based oxides, comparable to that of Pt/C. Altogether, this study opens up great opportunities for mullite-based catalysts to be a cost-effective alternative to Pt/C in diverse electrochemical energy storage and conversion systems.

10.
J Org Chem ; 82(5): 2523-2534, 2017 03 03.
Artigo em Inglês | MEDLINE | ID: mdl-28165232

RESUMO

A simple and efficient strategy for the synthesis of 1-propenylnaphthols from readily accessible 3-arylallylnaphthyl ethers has been developed. By using K2CO3 as base and 2-methoxyethanol as solvent, direct access to a wide range of 1-propenylnaphthols can be achieved in generally good yield (up to 99%) with high stereoselectivity toward the Z isomer. The control experiments indicate that the reaction proceeds through a sequential Claisen rearrangement/isomerization process. Furthermore, starting from the same material, the highly valuable 3-arylnaphtho[2,1-b]furans can be obtained in N,N-dimethylformamide and in the presence of Ag2O as the oxidant via a one-pot sequential Claisen rearrangement/isomerization/cyclization reaction. Mechanistic studies confirm that 1-propenylnaphthols are the key intermediates to form the 3-arylnaphtho[2,1-b]furans. In addition, these two operationally simple and practical protocols could be scaled up to a gram level.

11.
Artigo em Chinês | MEDLINE | ID: mdl-30134092

RESUMO

DNA barcoding technique is a fast and accurate method for species identification. The DNA barcoding based on cytochrome c oxidase subunit Ⅰ (COⅠ) has recently been successfully applied for species identification of Culicidae. In this paper, we introduce the technique and principle of DNA barcoding, application and limitation of the technique based on CO I gene for species identification, as well as research development on applications of other molecular makers such as COⅡ,16S RNA, and the first and the second internal transcribed spacers (ITS1 and ITS2) in species identification and to assist the COⅠ gene in identifying Culicidae species.


Assuntos
Culicidae , Código de Barras de DNA Taxonômico , Animais
12.
Adv Mater ; 28(24): 4943, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27311095

RESUMO

T. Ling, X.-W. Du, S. Z. Qiao, and co-workers report strongly coupled Nafion molecules and ordered-porous CdS networks for visible-light water splitting. The image conceptually shows how the three-dimensional ordered structure effectively harvests incoming light. As described on page 4935, the inorganic CdS skeleton is homogeneously passivated by the organic Nafion molecules to facilitate hydrogen generation.

13.
Small ; 12(23): 3181-8, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27145726

RESUMO

TiO2 has excellent electrochemical properties but limited solar photocatalytic performance in light of its large bandgap. One important class of visible-wavelength sensitizers of TiO2 is based on ZnFe2 O4 , which has shown fully a doubling in performance relative to pure TiO2 . Prior efforts on this important front have relied on presynthesized nanoparticles of ZnFe2 O4 adsorbed on a TiO2 support; however, these have not yet achieved the full potential of this system since they do not provide a consistently maximized area of the charge-separating heterointerface per volume of sensitizing absorber. A novel atomic layer deposition (ALD)-enhanced synthesis of sensitizing ZnFe2 O4 leaves grown on the trunks of TiO2 trees is reported. These new materials exhibit fully a threefold enhancement in photoelectrochemical performance in water splitting compared to pristine TiO2 under visible illumination. The new materials synthesis strategy relies first on the selective growth of FeOOH nanosheets, 2D structures that shoot off from the sides of the TiO2 trees; these templates are then converted to ZnFe2 O4 with the aid of a novel ALD step, a strategy that preserves morphology while adding the Zn cation to achieve enhanced optical absorption and optimize the heterointerface band alignment.

14.
Adv Mater ; 28(24): 4935-42, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27038367

RESUMO

Strongly coupled Nafion molecules and ordered porous CdS networks are fabricated for visible-light photoelectrochemical (PEC) hydrogen evolution. The Nafion layer coating shifts the band position of CdS upward and accelerates charge transfer in the photoelectrode/electrolyte interface. It is highly expected that the strong coupling effect between organic and inorganic materials will provide new routes to advance PEC water splitting.

15.
Mol Cell Biochem ; 395(1-2): 53-64, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24878992

RESUMO

The process of preadipocytes differentiation plays a vital role in adipose tissue expansion and many factors are involved in this event. Cathepsin B (CTSB), secreted from lysosome, has been reported in regulating a variety of physiological processes. In this study, we demonstrated CTSB promotes lipid accumulation and adipogenic genes expression in porcine primary preadipocytes by degrading fibronectin (Fn), a key component of extracellular matrix. Lithium chloride (LiCl) is an activator of Wnt/ß-catenin signaling through stabilizing ß-catenin. We found that CTSB can relieve the anti-adipogenic effects of LiCl, indicating that CTSB could impact Wnt/ß-catenin signaling pathway. Interestingly, Fn is an important target gene of Wnt/ß-catenin. So we considered that CTSB promote preadipocytes differentiation by suppressing these two pathways.


Assuntos
Adipócitos/citologia , Catepsina B/metabolismo , Matriz Extracelular/metabolismo , Fibronectinas/metabolismo , Cloreto de Lítio/farmacologia , Adipogenia , Animais , Catepsina B/genética , Diferenciação Celular , Células Cultivadas , Técnicas de Silenciamento de Genes , Suínos , Via de Sinalização Wnt/efeitos dos fármacos
16.
Mol Cell Biochem ; 395(1-2): 155-65, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24952481

RESUMO

MicroRNAs are a family of small, non-coding RNAs that regulate gene expression in a sequence-specific manner. Estrogen-related receptor α (ERRα) is an orphan nuclear receptor which plays an important role in adipocyte differentiation. Our previous Solexa sequencing results indicated a high expression of miR-125a in adult pig backfat. In this study, we predicated and experimentally validated ERRα as a target of miR-125a. To explore the role of miR-125a in porcine preadipocytes differentiation, miRNA agomir and antagomir were used to perform miR-125a overexpression or knockdown, respectively. Our results showed that overexpression of miR-125a could dramatically reduce the mRNA expression of adipogenic markers PPARγ, LPL, and aP2, as well as its target gene ERRα. Western blotting showed the protein level of aP2 and ERRα was also significantly down-regulated. The overexpression of miR-125a also led to a notable reduction in lipid accumulation which was detected by Oil Red O staining. In contrast, we observed promoted differentiation of porcine preadipocytes upon miR-125a inhibition. In conclusion, we verified miR-125a inhibits porcine preadipocytes differentiation through targeting ERRα for the first time, which may provide new insights in pork quality improvement and obesity control.


Assuntos
Adipócitos/fisiologia , MicroRNAs/genética , MicroRNAs/metabolismo , Receptores Estrogênicos/genética , Sus scrofa/fisiologia , Adipócitos/citologia , Animais , Diferenciação Celular , Células Cultivadas , Regulação da Expressão Gênica , Técnicas de Silenciamento de Genes , Modelos Biológicos , Receptores Estrogênicos/metabolismo
17.
Chem Commun (Camb) ; 50(45): 6023-6, 2014 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-24770847

RESUMO

A catalyst composed of [Pd(η(3)-C3H5)Cl]2 and N,N,N',N'-tetra(diphenylphosphinomethyl)pyridine-2,6-diamine (L) was found to be effective for one-pot synthesis of 2-substituted benzo[b]furans from 2-halophenols and alkynes. For 2-bromo-3-hydroxypyridine, the catalyst loading could be as low as 1 ppm and the turnover number (TON) was up to 870,000.


Assuntos
Alquinos/química , Benzofuranos/síntese química , Compostos Organometálicos/química , Paládio/química , Fenóis/química , Fosfinas/química , Catálise
18.
Int J Infect Dis ; 17(7): e498-504, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23485430

RESUMO

BACKGROUND: After an absence of 29 years, dengue virus type 3 (DENV-3) re-emerged in Guangzhou in 2009 and again in 2010. However, the geographical route by which the virus entered the city, and how it has changed genetically, remain unclear. Therefore, we carried out a comprehensive investigation into the molecular characteristics of the DENV-3 involved. METHODS: The envelope (E) genes of viruses isolated from dengue patients during the 2009-2010 epidemics were sequenced and compared with previously published E gene sequences of global representative DENV-3 strains available in GenBank, including isolates circulating in other provinces of China. RESULTS: A total of 13 isolates (seven from 2009 and six from 2010) were obtained from human serum samples. Phylogenetic analysis revealed that the isolates were grouped into three genotypes (I, III, and V) and then two clades within genotype III (genotype I from Indonesia, genotype III clade A from Côte d'Ivoire, genotype III clade B from Tanzania, and genotype V from Philippines). In addition, there were 1.3-9.0% and 0.5-3.9% differences in the nucleic and deduced amino acid sequences between the 2009 and 2010 strains, respectively. CONCLUSIONS: The DENV-3 viruses from the period 2009-2010 were not from the continuous spread of an epidemic strain or the re-emergence of the 2009 strains in the 2-year period. The introduction of different DENV-3 genotypes following more than one geographical route was an important contributing factor to the 2009-2010 dengue epidemics in Guangzhou.


Assuntos
Vírus da Dengue/genética , Dengue/epidemiologia , RNA Viral/genética , Proteínas do Envelope Viral/genética , China/epidemiologia , Dengue/genética , Vírus da Dengue/classificação , Vírus da Dengue/isolamento & purificação , Epidemias , Genótipo , Humanos , Epidemiologia Molecular , Filogenia , Reação em Cadeia da Polimerase em Tempo Real , Análise de Sequência de DNA
19.
Artigo em Chinês | MEDLINE | ID: mdl-23072139

RESUMO

OBJECTIVE: To perform molecular cloning of the AGO2 and Dcr-2 gene fragments associated with RNA interference pathway of Aedes albopictus and characterize the transcription level of the two genes across all life stages of the mosquito. METHODS: The degenerate primers were designed based on the conserved regions of AGO2 and Dcr-2 amino acid sequences, and the AGO2 and Dcr-2 cDNA fragments were amplified from total RNA of a female mosquito by RT-PCR. The PCR products were cloned into pMD18-T vector and transformed into E. coli DH5alpha strain, and the positive clones were selected and sequenced, with the results for homology analysis by Blastx. The specific primers were designed according to the sequences of AGO2 and Dcr-2 from Ae. albopictus, which were used to investigate the transcription levels of these two genes from eggs, I and II instars larvae, III and IV instars larvae, pupa, male and female mosquitoes by semi-quantitative RT-PCR. RESULTS: The AGO2 and Dcr-2 cDNA fragments obtained were 326 bp and 491 bp in length, with the Accession number of JQ764670 and JQ764671, respectively. The Blastx analysis showed that the AGO2 and Dcr-2 amino acid sequences shared 91% similarity to AGO2 of Ae. aegypti and 98% to Dcr-2 of Ae. albopictus. The transcription of AGO2 and Dcr-2 genes was detected in all life stages of Ae. albopictus, with the highest level of mRNA in female mosquitoes, which was 3.1 times and 15.5 times higher for AGO2 and Dcr-2 than in male mosquitoes, respectively, and significantly higher than other developmental stages (P<0.05). CONCLUSION: The AGO2 and Dcr-2 cDNA sequences have been partially obtained and the highest transcription level found in female Ae. albopictus, suggesting that AGO2 and Dcr-2 are the key genes of RNA interference in female mosquitoes.


Assuntos
Aedes/crescimento & desenvolvimento , Aedes/genética , Genes de Insetos , Proteínas de Insetos/metabolismo , Animais , Clonagem Molecular , Primers do DNA , DNA Complementar , Feminino , Proteínas de Insetos/genética , Larva/genética , Masculino , Interferência de RNA , Transcrição Genética
20.
J Vector Ecol ; 37(1): 230-40, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22548558

RESUMO

To understand its unprecedented resurgence, we examined the epidemiological, virological, and entomological features of dengue in Guangzhou during 1978-2009. Cases reported to the Guangzhou Centre for Disease Control and Prevention and data from virological and entomological surveillance were analyzed from three periods: 1978-1988, 1989-1999, and 2000-2009. Although cases decreased over time: 6,649 (1978-1988) to 6,479 (1989-1999) to 2,526 (2000-2009), geographical expansion resulted in districts with an average incidence >2.5/100,000, increasing from five (1978-1988, 1989-1999) to seven (2000-2009). Age distribution (mean age: 34.9 years) provided a trend of increasing dengue incidence among adults, and there was a significantly higher incidence among men with a sex ratio of 1.15:1 (P<0.001). Cases occurred from May through November with a peak between August and October, and a long-term trend was characterized by a three to five-year cyclical pattern. The most frequently isolated serotypes were DENV-2 (1978-1988) and DENV-1 (1989-1999 and 2000-2009). Seasonal fluctuations in immature densities of Aedes albopictus (sole transmission vector in Guangzhou) were consistent with the dengue seasonality. After a 30-year apparent absence, DENV-3 had reemerged in 2009. The current epidemiological situation is highly conducive to periodic dengue resurgences. Thus, a high degree of surveillance and strict control measures in source reduction should be maintained.


Assuntos
Dengue/epidemiologia , Dengue/virologia , Insetos Vetores/fisiologia , Adolescente , Adulto , Distribuição por Idade , Idoso , Animais , Criança , Pré-Escolar , China/epidemiologia , Culicidae/fisiologia , Dengue/transmissão , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Estações do Ano , Adulto Jovem
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