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1.
Chemosphere ; 234: 917-924, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31519100

RESUMO

Nickel, massively used in plating industry but detrimental to ecosystem, tends to form stable complexes with organic additives in industrial effluents. Currently, most of the available processes aim at water decontamination from free toxic metal ions and thus, could not effectively remove nickel-carboxyl complexes from water. Herein, we employed a proprietary combined process Fe(III)/UV/NaOH, namely Fe(III) displacement and UV irradiation followed by alkaline precipitation, to validate its feasibility on the efficient removal of nickel-carboxyl complexes from synthetic and authentic effluents. Fe(III)/UV/NaOH outperformed other commonly used processes including NaOH precipitation, UV/NaOH, Fe(III) coagulation, and Fenton/NaOH. Each unit of the combined process was optimized, and the underlying mechanism was elucidated. Fe(III) displacement favored the stoichiometric release of free nickel ions and formation of Fe(III)-carboxyl complexes, which could be decarboxylated via ligand-metal charge transfer under UV irradiation. The precipitation unit aims at simultaneously removing the released Ni along with Fe species. Attractively, the presence of other organic species (ethylene glycol, ethyl acetate and humic acid) and anions (chloride and sulfate) exerted very slight effect on the final Ni removal, whereas greatly adverse effect occurred on the Fenton process under similar conditions. The feasibility of the combined process was validated by testing on an authentic electroplating effluent, resulting in the residual Ni below 0.1 mg/L, the most stringent discharge standard for Ni in electroplating effluent in China.


Assuntos
Compostos Férricos/química , Níquel/química , Poluentes Químicos da Água/química , Purificação da Água/métodos , China , Ecossistema , Galvanoplastia , Hidróxido de Sódio , Sulfatos , Raios Ultravioleta , Água , Poluentes Químicos da Água/análise
2.
New Phytol ; 224(2): 860-874, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-30883796

RESUMO

Extracellular DNA, released by damaged plant cells, acts as a damage-associated molecular pattern (DAMP). We demonstrated previously that the small brown planthopper (Laodelphax striatellus, SBPH) secreted DNase II when feeding on artificial diets. However, the function of DNase II in insect feeding remained elusive. The influences of DNase II on SBPHs and rice plants were investigated by suppressing expression of DNase II or by application of heterogeneously expressed DNase II. We demonstrated that DNase II is mainly expressed in the salivary gland and is responsible for DNA-degrading activity of saliva. Knocking down the expression of DNase II resulted in decreased performance of SBPH reared on rice plants. The dsDNase II-treated SBPH did not influenced jasmonic acid (JA), salicylic acid (SA), ethylene (ET) pathways, but elicited a higher level of H2 O2 and callose accumulation. Application of heterogeneously expressed DNase II in DNase II-deficient saliva slightly reduced the wound-induced defence response. We propose a DNase II-based invading model for SBPH feeding on host plants, and provide a potential target for pest management.

3.
Water Res ; 153: 21-28, 2019 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-30685633

RESUMO

Considerable amount of phosphorous is present as organic phosphonates (usually in the form of metal complexes, e.g., Ca(II)-phosphonate) in domestic and industrial effluents, which cannot be effectively removed by traditional processes for phosphate. Herein, we employed a proprietary process, i.e., Fe(III) displacement/UV irradiation/co-precipitation (denoted Fe(III)/UV/NaOH), to enable an efficient removal of Ca(II)-phosphonate complexes from water. The combined process includes three basic steps, i.e., Fe(III) replacement with the complexed Ca(II) to form Fe(III)-phosphonate of high photo-reactivity, UV-mediated degradation of Fe(III)-phosphonate to form phosphate and other intermediates, and the final phosphorous removal via co-precipitation at pH = 6. The operational conditions for the combined process to remove a typical phosphonate Ca(II)-NTMP (nitrilotrismethylenephosphonate) are optimized, where ∼60% NTMP is transformed to phosphate with the total phosphorous reduction from 1.81 mg/L to 0.17 mg/L. Under UV irradiation, the cleavage of NTMP is identified at the C-N and C-P bonds to form the intermediate products and phosphate in sequence. Also, the combined process is employed for treatment of two authentic effluents before and after activated sludge treatment, resulting in the phosphorous drop from 4.3 mg/L to 0.23 mg/L and from 0.90 mg/L to 0.14 mg/L respectively, which is much superior to other processes including Fenton/co-precipitation. In general, the combined process exhibits great potential for efficient removal of phosphonates from contaminated waters.


Assuntos
Organofosfonatos , Poluentes Químicos da Água , Compostos Férricos , Peróxido de Hidrogênio , Raios Ultravioleta , Água
4.
J Am Chem Soc ; 141(9): 3901-3909, 2019 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-30696242

RESUMO

Enantioenriched molecules bearing indole-substituted stereocenters form a class of privileged compounds in biological, medicinal, and organic chemistry. Thus, the development of methods for asymmetric indole alkylation is highly valuable in organic synthesis. Traditionally, achieving N-selectivity in indole alkylation reactions is a significant challenge, since there is an intrinsic preference for alkylation at C3, the most nucleophilic position. Furthermore, selective and predictable access to either N- or C3-alkylated chiral indoles using catalyst control has been a long-standing goal in indole functionalization. Herein, we report a ligand-controlled regiodivergent synthesis of N- and C3-alkylated chiral indoles that relies on a polarity reversal strategy. In contrast to conventional alkylation reactions in which indoles are employed as nucleophiles, this transformation employs electrophilic indole derivatives, N-(benzoyloxy)indoles, as coupling partners. N- or C3-alkylated indoles are prepared with high levels of regio- and enantioselectivity using a copper hydride catalyst. The regioselectivity is governed by the use of either DTBM-SEGPHOS or Ph-BPE as the supporting ligand. Density functional theory (DFT) calculations are conducted to elucidate the origin of the ligand-controlled regiodivergence.

5.
Sci Total Environ ; 654: 35-42, 2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30439692

RESUMO

The electroless nickel (EN) industry has suffered from the reduction in Ni concentration to lower than 0.1 mg/L. Hence, Ni speciation along a typical sequential treatment scheme has important implications to optimize the design of advanced treatment. For the first time, we revealed the Ni speciation in segmented EN outfall effluents by virtue of multiple analytical methods. After ensuring all the Ni-bearing complexes were completely dissolved by size-fractioned ultrafiltration trials, customized mass spectra analysis was conducted. In a series of ICP-MS assays, the potential polyatomic interfering species was primarily excluded. The chromatography hyphenated IC-ICP-MS and SEC-ICP-MS results demonstrated that the dominant Ni species in the EN effluents was similar to EDTA-Ni but with a smaller size. The LC-MS experiment further distinguished several typical Ni-bearing complexes. Although Ni concentration declined continuously along the treatment scheme, the number of detected Ni-bearing complexes gradually increased but with lower molecular weights. Most of the detected mononuclear complexes had higher indexes of hydrogen deficiency (IHD) than EDTA-Ni, whereas it was believed that the similar stereo ring shape was widespread in the EN effluent. Considering the efficient Ni decrease after the Fenton unit, further post-treatment approaches featuring higher active radical yields were suggested.

6.
Environ Sci Technol ; 52(18): 10657-10664, 2018 09 18.
Artigo em Inglês | MEDLINE | ID: mdl-30130960

RESUMO

Fenton reaction is a widely used pretreatment technology to degrade toxic metal-organic complexes. However, its efficiency is greatly compromised for Cr(III)-organic complexes due to accumulation of more toxic Cr(VI) and pH dependence. Herein, we proposed a combined pyrite/H2O2-precipitation process to efficiently remove Cr(III) (initially at 10.4 mg Cr/L) complexed by various ligands (citrate, EDTA, oxalate, and tartrate). Negligible Cr(VI) and <0.3 mg/L Cr were detected in the effluent treated by pyrite/H2O2-precipitation over a wide pH range of 3-9. In contrast, > 0.5 mg/L Cr(VI) and >5 mg/L Cr remained after treatment by the ZVI/H2O2-precipitaion process at pH0 > 5. As for the mechanisms, pyrite/H2O2 produced a considerable amount of aqueous Fe(II) to initiate Fenton reaction, concurrently releasing massive H+ to keep the reaction pH at ∼3.0 irrespective of the initial pHs. The generated •OH radicals oxidized Cr(III) into Cr(VI) and thereby releasing the organic ligands for further mineralization. The generated Cr(VI) was in situ reduced back to Cr(III) by aqueous Fe(II) and FeS2. Subsequently, all the free metal ions including Cr(III), Fe(III), and Fe(II) were removed via precipitation. Kinetic modeling of the pyrite/H2O2 process involving 17 reactions was performed to verify the proposed mechanism. Additionally, the effectiveness of the combined process was further validated by its satisfactory performance in treating authentic tannery wastewater.


Assuntos
Peróxido de Hidrogênio , Água , Cromo , Descontaminação , Compostos Férricos , Ferro , Oxirredução , Sulfetos
7.
Proc Natl Acad Sci U S A ; 115(20): 5175-5180, 2018 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-29712872

RESUMO

Cuticle, mainly composed of chitin and cuticular proteins (CPs), is a multifunctional structure of arthropods. CPs usually account for >1% of the total insect proteins. Why does an insect encode so many different CP genes in the genome? In this study, we use comprehensive large-scale technologies to study the full complement of CPs (i.e., the CP-ome) of the brown planthopper (BPH), Nilaparvata lugens, a major rice plant pest. Eight CP families (CPR, CPF, TWDL, CPLCP, CPG, CPAP1, CPAP3, and CPAPn) including 140 proteins in BPH, in which CPAPn is a CP family that we discovered. The CPG family that was considered to be restricted to the Lepidoptera has also been identified in BPH. As reported here, CPLCP family members are characterized by three conserved sequence motifs. In addition, we identified a testis protein family with a peritrophin A domain that we named TPAP. We authenticated the real existence of 106 proteins among the 140 CPs. RNA interference (RNAi) experiments were conducted against 135 CP genes in early- and late-instar nymphs and newly emerged female adults, demonstrating that 32 CPs were essential for BPH normal development or egg production. Combined RNAi experiments suggested redundant and complementary functions of the large number of CPs. Transcriptomic data revealed that the CP genes were expressed in a tissue-specific manner, and there were four clusters of developmental expression patterns. This study gives a comprehensive understanding of the roles of CPs in an insect cuticle.


Assuntos
Hemípteros/genética , Proteínas de Insetos/genética , Família Multigênica , Interferência de RNA , Transcriptoma , Animais , Variação Genética , Hemípteros/crescimento & desenvolvimento , Proteínas de Insetos/antagonistas & inibidores , Proteínas de Insetos/metabolismo
8.
Polymers (Basel) ; 10(9)2018 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-30960888

RESUMO

Cellulose is the most abundant and widely used biopolymer on earth and can be produced by both plants and micro-organisms. Among bacterial cellulose (BC)-producing bacteria, the strains in genus Komagataeibacter have attracted wide attention due to their particular ability in furthering BC production. Our previous study reported a new strain of genus Komagataeibacter from a vinegar factory. To evaluate its capacity for BC production from different carbon sources, the present study subjected the strain to media spiked with 2% acetate, ethanol, fructose, glucose, lactose, mannitol or sucrose. Then the BC productivity, BC characteristics and biochemical transformation pathways of various carbon sources were fully investigated. After 14 days of incubation, strain W1 produced 0.040⁻1.529 g L-1 BC, the highest yield being observed in fructose. Unlike BC yields, the morphology and microfibrils of BCs from different carbon sources were similar, with an average diameter of 35⁻50 nm. X-ray diffraction analysis showed that all membranes produced from various carbon sources had 1⁻3 typical diffraction peaks, and the highest crystallinity (i.e., 90%) was found for BC produced from mannitol. Similarly, several typical spectra bands obtained by Fourier transform infrared spectroscopy were similar for the BCs produced from different carbon sources, as was the Iα fraction. The genome annotation and Kyoto Encyclopedia of Genes and Genomes analysis revealed that the biochemical transformation pathways associated with the utilization of and BC production from fructose, glucose, glycerol, and mannitol were found in strain W1, but this was not the case for other carbon sources. Our data provides suggestions for further investigations of strain W1 to produce BC by using low molecular weight sugars and gives clues to understand how this strain produces BC based on metabolic pathway analysis.

9.
Chemosphere ; 193: 42-49, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29126064

RESUMO

Various organic compounds extensively used in the leather industry could influence the performance of alkaline precipitation with Cr(III). This study focused on two typical Cr(III)-bearing complexes (Cr(III)-collagen and Cr(III)-citrate) ubiquitous in tannery effluent yet with distinct treatment efficiencies, as Cr(III) was much more difficult to remove in the Cr(III)-citrate solution. Comprehensive analytical methods were employed to explore the intrinsic mechanism. It was found that a lower removal efficiency towards Cr(III) was significantly associated with higher oligomers. The molecular size of the Cr(III)-citrate complex continued to increase with rising pH, making it larger overall than Cr(III)-collagen species. The growing oligomer moiety of dissolved Cr(III)-complex species could persist in the stronger basic pH range, leading to the large amount of residual Cr(III) in the Cr(III)-citrate system. Combining this result with potentiometric titration and X-ray photoelectron spectroscopy data, it was believed that the polymeric species other than monomers facilitated resisting the attack from hydroxide ions, and the postulated Cr(III)-citrate species towards higher oligomers were discovered. Beyond that, both charge neutralization and sweeping effects were presented among the gradually emerging flocs in the Cr(III)-collagen system together with the electric double layer compression effect derived from salinity, thus resulting in a larger floc size and higher Cr(III) removal efficiency in saline solutions.


Assuntos
Cromo/química , Curtume , Águas Residuárias/química , Poluentes Químicos da Água/análise , Cromo/análise , Citratos , Ácido Cítrico/química , Concentração de Íons de Hidrogênio , Hidróxidos , Indústrias , Eliminação de Resíduos Líquidos
10.
Water Res ; 126: 172-178, 2017 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-28946060

RESUMO

Most available processes are incapable of removing Cr(III)-organic complexes from water due to their high solubility, extremely slow decomplexation rate, and possible formation of more toxic Cr(VI) during oxidation. Herein, we proposed a new combined process, i.e., UV/Fe(III) followed by alkaline precipitation (namely UV/Fe(III)+OH), to achieve highly efficient and environmentally benign removal of Cr(III)-organic complexes from water. The combined process could remove Cr(III)-citrate from 10.4 mg Cr/L to 0.36 mg Cr/L and ∼60% total organic carbon as well. More attractively, negligible Cr(VI) (<0.06 mg/L) was formed during the process. In the viewpoint of mechanism, the added Fe(III) generates ·OH radicals to transform Cr(III) into Cr(VI) and simultaneously released the citrate ligand to form Fe(III)-citrate simultaneously. Then, the photolysis of Fe(III)-citrate under UV irradiation involved the citrate degradation and the production of massive Fe(II) species, which in turn transformed the formed Cr(VI) back to Cr(III). The free metal ions, including Cr(III), Fe(II) and Fe(III) were removed by the subsequent alkaline precipitation. Also, the combined process is applicable to other Cr(III) complexes with EDTA, tartrate, oxalate, acetate. The applicability of the combined process was further demonstrated by treating two real tanning effluents, resulting in the residual Cr(III) below 1.5 mg/L (the discharge standard of China) and negligible formation of Cr(VI) (<0.004 mg/L) as well. In general, the combined process has a great potential for efficient removal of Cr(III) complexes from contaminated waters.


Assuntos
Compostos de Cromo/isolamento & purificação , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Acetatos/química , Cromo/química , Compostos de Cromo/química , Ácido Edético/química , Radical Hidroxila/química , Ferro/química , Oxirredução , Fotólise , Solubilidade , Tartaratos/química , Raios Ultravioleta
11.
Open Biol ; 7(6)2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-28615473

RESUMO

Most animals are oviparous. However, the genes regulating egg shell formation remain not very clear. In this study, we found that Nilaparvata lugens Forkhead box transcription factor L2 (NlFoxL2) directly activated follicle cell protein 3C (NlFcp3C) to regulate chorion formation. NlFoxL2 and NlFcp3C had a similar expression pattern, both highly expressed in the follicular cells of female adults. Knockdown of NlFoxL2 or NlFcp3C also resulted in the same phenotypes: obesity and female infertility. RNA interference (RNAi) results suggested that NlFcp3C is a downstream gene of NlFoxL2 Furthermore, transient expression showed that NlFoxL2 could directly activate the NlFcp3C promoter. These results suggest that NlFcp3C is a direct target gene of NlFoxL2. Depletion of NlFoxL2 or NlFcp3C prevented normal chorion formation. Our results first revealed the functions of Fcp3C and FoxL2 in regulation of oocyte maturation in an oviparous animal.


Assuntos
Proteínas do Ovo/genética , Proteína Forkhead Box L2/metabolismo , Animais , Córion/citologia , Córion/crescimento & desenvolvimento , Sequência Conservada , Proteínas do Ovo/metabolismo , Feminino , Proteína Forkhead Box L2/genética , Técnicas de Silenciamento de Genes , Hemípteros/genética , Hemípteros/crescimento & desenvolvimento , Oócitos/metabolismo , Oócitos/ultraestrutura , Alinhamento de Sequência
12.
Angew Chem Int Ed Engl ; 55(50): 15559-15563, 2016 12 12.
Artigo em Inglês | MEDLINE | ID: mdl-27862732

RESUMO

A method for the palladium-catalyzed fluorination of cyclic vinyl triflates has been developed. As with several previous palladium-catalyzed fluorination reactions using fluoride salts, controlling the regioselectivity presented a challenge in developing a practical synthetic procedure. The addition of triethyl(trifluoromethyl)silane (TESCF3 ) was found to effectively address this problem and resulted in drastically improved regioselectivities in this palladium-catalyzed fluorination reaction. This discovery, along with the use of a new biarylphosphine ligand, allowed for the development of an efficient and highly regioselective protocol for the fluorination of vinyl triflates. This method is compatible with a range of sensitive functional groups and provides access to five-, six-, and seven-membered cyclic vinyl fluorides.


Assuntos
Mesilatos/química , Paládio/química , Silanos/química , Compostos de Vinila/química , Catálise , Ciclização , Halogenação , Mesilatos/síntese química , Silanos/síntese química , Estereoisomerismo , Compostos de Vinila/síntese química
13.
J Hazard Mater ; 316: 169-77, 2016 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-27232728

RESUMO

It is difficult to completely remove Cr(III) from tannery effluent by alkaline precipitation due to the abundance of strong organic ligands. Thereby, the speciation of the residual Cr after alkaline precipitation is of crucial significance to guide the selection and design of further treatment process. For the first time, we revealed the speciation of the residual Cr with the aid of comprehensive analytical techniques. Results showed that the residual Cr(III) mostly located in two size ranges, i.e. the 13-100nm fraction and the <4nm fraction. Combined spectral analyses demonstrated Cr(III) was coordinated by carboxyl groups or hydroxyl groups in both fractions, while the complexation by nitrogen-containing groups was excluded by the total nitrogen and UPLC-MS analysis in the two fractions, respectively. Based on the comprehensive analyses, the structures of Cr(III) complexes in both fractions were proposed. Cr(III) cross-linked the carboxyl groups from polyacrylic acid chains to form the network gel structure in the 13-100nm fraction, while the complex structure of Cr(III) in the <4nm fraction was formed through hydroxyl-carboxyl chelation by masking agents such as tartrate and citrate. Although polyoxyethylene ether was abundantly present, it was responsible for the complexation of Cr(III) in neither fraction.

14.
Insect Sci ; 23(3): 478-86, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26792263

RESUMO

There exists a kind of symbiotic bacterium named "Candidatus Arsenophonus nilaparvatae" in the brown planthopper (BPH), Nilaparvata lugens. After being filtered and assembled from the BPH genome sequencing project, the genome sequence of this bacterial symbiont was obtained. After initial analysis based on the genome, we have found its potential role to synthesize B vitamins for the host. In order to better understand the lifestyle and the genomic changes of this symbiotic bacterium after the symbiotic relationship was established, we further report the characteristics of this draft genome. Compared with several other related bacteria, "Candidatus Arsenophonus nilaparvatae" has proven to be a facultative endosymbiont at the genomic level. Concurrently, the presence of fimbriae and flagella formation related genes indicates this maternally transmitted endosymbiont is most likely to retain the capacity to invade new hosts. Through further analysis of annotated gene sets, we also find evidence of genome reduction in its secretion system and metabolic pathways. These findings reflect its evolutionary trend to be an obligate one and enable a deeper study of microbe-insect interactions.


Assuntos
Enterobacteriaceae/genética , Genoma Bacteriano , Hemípteros/microbiologia , Animais , Proteínas de Bactérias/metabolismo , Hemípteros/fisiologia , Filogenia , Análise de Sequência de DNA , Simbiose , Complexo Vitamínico B/biossíntese
15.
Insect Biochem Mol Biol ; 63: 124-32, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26107750

RESUMO

The multicopper oxidase (MCO) family of enzymes includes laccases, ascorbate oxidases, bilirubin oxidases and a subgroup of metal oxidases. On the basis of a bioinformatics investigation, we identified 7 genes encoding putative multicopper oxidase proteins in the genome of the brown planthopper (BPH), Nilaparvata lugens (Hemiptera: Delphacidae). MCO1 and MCO2 are conserved, while others diverse in insects. Analysis of developmental and tissue-specific expression patterns revealed the following: NlMCO2 was mainly expressed in the integument, and its expression peaked periodically during molting; NlMCO3 was an ovary-specific MCO gene with a high expression level only at the adult stage; NlMCO4 was a salivary gland-specific MCO gene that was expressed at all developmental stages; NlMCO5 only had short-term expression in the middle of the fourth instar stage and was expressed mainly in the gut; NlMCO6 had a developmental expression pattern similar to that of NlMCO2 and was expressed in most N. lugens tissues; and NlMCO1 was expressed in most N. lugens tissues except for the testis, whereas NlMCO7 was mainly expressed in the gut and the Malpighian tube. BPHs injected with double-stranded RNA (dsRNA) targeting NlMCO2 failed to pigment and sclerotize, were colorless and soft-bodied and subsequently died in a short time. Lethal phenotypes were also observed in insects challenged by dsRNA targeting NlMCO6. However, no observable morphological or internal structural abnormality was obtained in the insects treated with dsRNA for NlMCO1, NlMCO3, NlMCO4, NlMCO5 or NlMCO7.


Assuntos
Hemípteros/enzimologia , Hemípteros/genética , Oxirredutases/genética , Sequência de Aminoácidos , Animais , Feminino , Expressão Gênica , Hemípteros/crescimento & desenvolvimento , Masculino , Dados de Sequência Molecular , Muda/genética , RNA de Cadeia Dupla
16.
Nature ; 519(7544): 464-7, 2015 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-25799997

RESUMO

Wing polyphenism is an evolutionarily successful feature found in a wide range of insects. Long-winged morphs can fly, which allows them to escape adverse habitats and track changing resources, whereas short-winged morphs are flightless, but usually possess higher fecundity than the winged morphs. Studies on aphids, crickets and planthoppers have revealed that alternative wing morphs develop in response to various environmental cues, and that the response to these cues may be mediated by developmental hormones, although research in this area has yielded equivocal and conflicting results about exactly which hormones are involved. As it stands, the molecular mechanism underlying wing morph determination in insects has remained elusive. Here we show that two insulin receptors in the migratory brown planthopper Nilaparvata lugens, InR1 and InR2, have opposing roles in controlling long wing versus short wing development by regulating the activity of the forkhead transcription factor Foxo. InR1, acting via the phosphatidylinositol-3-OH kinase (PI(3)K)-protein kinase B (Akt) signalling cascade, leads to the long-winged morph if active and the short-winged morph if inactive. InR2, by contrast, functions as a negative regulator of the InR1-PI(3)K-Akt pathway: suppression of InR2 results in development of the long-winged morph. The brain-secreted ligand Ilp3 triggers development of long-winged morphs. Our findings provide the first evidence of a molecular basis for the regulation of wing polyphenism in insects, and they are also the first demonstration--to our knowledge--of binary control over alternative developmental outcomes, and thus deepen our understanding of the development and evolution of phenotypic plasticity.


Assuntos
Hemípteros/anatomia & histologia , Hemípteros/metabolismo , Receptor de Insulina/metabolismo , Asas de Animais/crescimento & desenvolvimento , Asas de Animais/metabolismo , Animais , Feminino , Fatores de Transcrição Forkhead/deficiência , Fatores de Transcrição Forkhead/metabolismo , Hemípteros/enzimologia , Hemípteros/genética , Insulina/metabolismo , Masculino , Dados de Sequência Molecular , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Receptor de Insulina/deficiência , Transdução de Sinais , Asas de Animais/anatomia & histologia , Asas de Animais/enzimologia
17.
Chem Commun (Camb) ; 50(33): 4361-3, 2014 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-24643782

RESUMO

A mild and efficient method for the synthesis of 3-trifluoromethylpyrazoles has been established via trifluoromethylation/cyclization of α,ß-alkynic hydrazones using a hypervalent iodine reagent under transition-metal-free conditions.


Assuntos
Hidrazonas/química , Iodo/química , Pirazóis/química , Catálise , Ciclização , Metilação , Pirazóis/síntese química
18.
Genome Biol ; 15(12): 521, 2014 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-25609551

RESUMO

BACKGROUND: The brown planthopper, Nilaparvata lugens, the most destructive pest of rice, is a typical monophagous herbivore that feeds exclusively on rice sap, which migrates over long distances. Outbreaks of it have re-occurred approximately every three years in Asia. It has also been used as a model system for ecological studies and for developing effective pest management. To better understand how a monophagous sap-sucking arthropod herbivore has adapted to its exclusive host selection and to provide insights to improve pest control, we analyzed the genomes of the brown planthopper and its two endosymbionts. RESULTS: We describe the 1.14 gigabase planthopper draft genome and the genomes of two microbial endosymbionts that permit the planthopper to forage exclusively on rice fields. Only 40.8% of the 27,571 identified Nilaparvata protein coding genes have detectable shared homology with the proteomes of the other 14 arthropods included in this study, reflecting large-scale gene losses including in evolutionarily conserved gene families and biochemical pathways. These unique genomic features are functionally associated with the animal's exclusive plant host selection. Genes missing from the insect in conserved biochemical pathways that are essential for its survival on the nutritionally imbalanced sap diet are present in the genomes of its microbial endosymbionts, which have evolved to complement the mutualistic nutritional needs of the host. CONCLUSIONS: Our study reveals a series of complex adaptations of the brown planthopper involving a variety of biological processes, that result in its highly destructive impact on the exclusive host rice. All these findings highlight potential directions for effective pest control of the planthopper.


Assuntos
Genoma de Inseto , Hemípteros/genética , Hemípteros/microbiologia , Herbivoria , Oryza/fisiologia , Adaptação Biológica , Animais , Artrópodes/genética , Ásia , Bactérias/genética , Evolução Molecular , Genômica , Hemípteros/fisiologia , Especificidade de Hospedeiro , Dados de Sequência Molecular , Família Multigênica , Filogenia , Homologia de Sequência do Ácido Nucleico , Simbiose
19.
Angew Chem Int Ed Engl ; 52(40): 10573-6, 2013 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-23963827

RESUMO

From methyl to nitrile: A mild ammoxidation method, which directly converts methyl arenes into aromatic nitriles, has been developed by using Pd(OAc)2 and N-hydroxyphthalimide (NHPI) as the catalysts, and tert-butyl nitrite as the nitrogen source and oxidant.

20.
Org Lett ; 15(14): 3730-3, 2013 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-23808704

RESUMO

An efficient and practical methodology has been developed to introduce the CF3 group onto quinones through Cu(I)-catalyzed direct C-H trifluoromethylation of quinones.


Assuntos
Cobre/química , Hidrocarbonetos Fluorados/química , Quinonas/química , Catálise , Estrutura Molecular , Estereoisomerismo
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