Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 27
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Chemistry ; 29(35): e202300391, 2023 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-37069130

RESUMO

A three-component umpolung cascade coupling reaction of phenols, C60 , and different nucleophiles which includes H2 O, alcohols, triphenylamines and carbazoles was developed. Furthermore, one-pot 1,4-bisphenol coupling on C60 has been realized by this method. This practical protocol features high chemo- and regioselectivity, wide substrate range, easy operation and low cost, thus providing a robust method for the one-pot synthesis of various unsymmetrical 1,4-[60]fullerephenols.

2.
J Org Chem ; 88(1): 116-131, 2023 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-36538325

RESUMO

A KOtBu-promoted, three-component cross-coupling of arenes(indoles/phenols), C60, and (per/poly)fluoroarenes has been established for the one-pot efficient synthesis of various 1,4-arene-bridged bis(polyfluoroaryl)-functionalized [60]fullerenes. This developed reaction system demonstrates good functional group compatibilities with broad substrate scope, which exhibits high regio- and chemoselectivities. Further control experiment succeeded in providing a one-pot protocol for the synthesis of various 1,2-N-(per/poly)fluoroarene-substituted 1,2-(3-indole)(hydro)fullerenes.

3.
J Org Chem ; 87(12): 7945-7954, 2022 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-35671227

RESUMO

An unprecedented multicomponent domino reaction of [60]fullerene, indole, and DMSO/HCl has been developed for the one-pot efficient synthesis of diverse N-substituted [60]fulleroindole derivatives. This methodology features simple operation, low cost, and transition-metal-circumvented and good functional group tolerance in indole.

4.
Phys Rev Lett ; 126(10): 103601, 2021 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-33784152

RESUMO

Flat bands play an important role in diffraction-free photonics and attract fundamental interest in many-body physics. Here we report the engineering of flat-band localization of collective excited states of atoms in Creutz superradiance lattices with tunable synthetic gauge fields. Magnitudes and phases of the lattice hopping coefficients can be independently tuned to control the state components of the flat band and the Aharonov-Bohm phases. We can selectively excite the flat band and control the flat-band localization with the synthetic gauge field. Our study provides a room-temperature platform for flat bands of atoms and holds promising applications in exploring correlated topological materials.

5.
Plant Physiol Biochem ; 151: 214-222, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32229406

RESUMO

NAC [No apical meristem (NAM), Arabidopsis transcription activation factor (ATAF), Cup-shaped cotyledon (CUC)] transcription factors (TFs) play an important role in plant growth and response to various environmental stress. Drought stress is the primary factor limiting the growth and fruit quality of grapevines worldwide. However, the biological function of the NAC family members in grapevine is not clear. In this study, we reported that VvNAC08, a novel NAC transcription factor gene, was expressed after drought, salicylic acid (SA) and abscisic acid (ABA), jasmonic acid (JA) and melatonin (MT) treatments in grapevine. VvNAC08 was expressed in various tissues. The open reading frame (ORF) of VvNAC08 was 792 bp, encoding 263 amino acids. The VvNAC08 protein could bind to NACRS [CGTA/CACG] in yeast. When subjected to drought and dehydration stress, VvNAC08-overexpression (OE) Arabidopsis had a higher survival rate and a lower water loss rate than wild type (WT) plants. Under drought conditions, transgenic Arabidopsis overexpressing VvNAC08 had a lower malondialdehyde (MDA), H2O2 contents, but a higher peroxidase (POD), superoxide dismutase (SOD) and catalase (CAT) activities as well as more proline content. Moreover, the expressions of marker genes, including ABI5, AREB1, COR15A, COR47, P5CS, RD22, and RD29A, were up-regulated in VvNAC08-overexpression lines when subjected to drought treatments. The results suggest that the transgenic Arabidopsis overexpressing VvNAC08 enhances resistance to drought while up-regulating the expressions of ABA- and stress-related genes.


Assuntos
Arabidopsis/fisiologia , Secas , Proteínas de Plantas/genética , Estresse Fisiológico , Fatores de Transcrição/genética , Vitis/genética , Arabidopsis/genética , Regulação da Expressão Gênica de Plantas , Plantas Geneticamente Modificadas/fisiologia
6.
Plant Physiol Biochem ; 146: 98-111, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31734522

RESUMO

Drought stress is the primary factor limiting the growth and fruit quality of grapevines worldwide. However, the biological function of the NAC [No apical meristem (NAM), Arabidopsis transcription activation factor (ATAF), Cup-shaped cotyledon (CUC)] transcription factor (TF) in grapevine is not clear. In this study, we reported that VvNAC17, a novel NAC transcription factor, was expressed in various tissues following drought, high temperature (45 °C), freezing (4 °C), salicylic acid (SA), and abscisic acid (ABA) treatments in grapevine. The VvNAC17 protein was localized in the nucleus of Arabidopsis thaliana protoplasts and demonstrated transcriptional activation activities at its C-terminus in yeast. The VvNAC17 gene was overexpressed in Arabidopsis thaliana. Under mannitol and salt stress, the germination rates of the VvNAC17-overexpression lines were higher than those of the wild-type plants, as were the root lengths. The VvNAC17-overexpression lines showed greater tolerance to freezing stress along with a higher survival rate. Following ABA treatment, the seed germination rate and the root length of the VvNAC17-overexpression lines were inhibited, and the stomatal opening and stomatal density were reduced. When subjected to drought and dehydration stress, the VvNAC17-overexpression lines showed improved survival and reduced water loss rates in comparison to the wild-type plants. Under drought conditions, the VvNAC17-overexpression lines had lower malondialdehyde and H2O2 contents, but higher peroxidase, superoxide dismutase, and catalase activities as well as higher proline content. Moreover, the expression of marker genes, including ABI5, AREB1, COR15A, COR47, P5CS, RD22, and RD29A, was up-regulated in the VvNAC17-overexpression lines when subjected to ABA and drought treatments. The results suggest that in transgenic Arabidopsis over-expression of VvNAC17 enhances resistance to drought while up-regulating the expression of ABA- and stress-related genes.


Assuntos
Arabidopsis , Vitis , Ácido Abscísico , Secas , Congelamento , Regulação da Expressão Gênica de Plantas , Peróxido de Hidrogênio , Proteínas de Plantas , Plantas Geneticamente Modificadas , Salinidade , Estresse Fisiológico , Fatores de Transcrição
7.
Phys Rev Lett ; 122(2): 023601, 2019 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-30720297

RESUMO

Chiral edge currents play an important role in characterizing topological matter. In atoms, they have been observed at such a low temperature that the atomic motion can be measured. Here we report the first experimental observation of chiral edge currents in atoms at room temperature. Staggered magnetic fluxes are induced by the spatial phase difference between two standing-wave light fields, which couple atoms to form a momentum-space zigzag superradiance lattice. The chiral edge currents are measured by comparing the directional superradiant emissions of two timed Dicke states in the lattice. Our results pave the way for simulating topological physics in hot atoms.

8.
Molecules ; 23(8)2018 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-30096898

RESUMO

Amino acid contents and their derived volatile compositions in Cabernet Sauvignon grapes and wines after regulated deficit irrigation (RDI) were investigated during the 2015 and 2016 growing seasons in Yinchuan (NingXia, China). High-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS) were used for amino acid and volatile compound analyses. Three RDI strategies were tested: 60% (RDI-1), 70% (RDI-2), and 80% (RDI-3) of grapevine estimated evapotranspiration (ETc), and 100% ETc was used as the control group (CK). RDI-treated vines had lower yields and berry weights with higher total soluble solids than the control treatment. RDI-1 increased proline levels in berries and wines. RDI-2 enhanced tyrosine and asparagine levels in wines. RDI-3 enhanced arginine, alanine, valine, leucine, and isoleucine levels in berries and wines. RDI-2 and RDI-3 increased the concentrations of 2-methyl-1-butyl acetate, benzaldehyde, 3-methyl-1-pentanol, and 3-methyl-1-butanol in wines. The accumulation of volatile compounds was closely related to the amino acid concentrations-especially isoleucine, valine, and leucine-in grapes. Our results showed that RDI treatments altered amino acid concentrations and their derived volatile compositions in wines.


Assuntos
Irrigação Agrícola , Aminoácidos/análise , Frutas/química , Vitis/química , Compostos Orgânicos Voláteis/análise , Vinho/análise , Análise por Conglomerados , Tempo (Meteorologia)
9.
Sci Rep ; 8(1): 1609, 2018 01 25.
Artigo em Inglês | MEDLINE | ID: mdl-29371639

RESUMO

As important secondary plant metabolites, naphthoquinones exhibit a wide range of biological activities. However, their potential as sustainable alternatives to synthetic acaricides has not been studied. This study for the first time investigates the acaricidal activity of naphthoquinones against Psoroptes cuniculi in vitro. Furthermore, the in vivo activity, the skin irritation effects, the cytotoxicity and the inhibitory activities against mite acetylcholinesterase (AChE) and glutathione S-transferase (GST) of the two compounds that displayed the best insecticidal activity in vitro were evaluated. Among fourteen naphthoquinones and their analogs, juglone and plumbagin were observed to possess the strongest acaricidal activities against P. cuniculi with LC50 values of 20.53 ppm and 17.96 ppm, respectively, at 24 h. After three treatments, these two chemicals completely cured naturally infested rabbits in vivo within 15 days, and no skin irritation was found in any of the treated rabbits. Compared to plumbagin, juglone presented no or weak cytotoxicity against HL-7702 cells. Moreover, these two chemicals significantly inhibited AChE and GST activity. These results indicate that juglone has promising toxicity against P. cuniculi, is safe for both humans and animals at certain doses, and could be used as a potential alternative bio-acaricide for controlling the development of psoroptic mange in agricultural applications.


Assuntos
Acaricidas/farmacologia , Agricultura/métodos , Naftoquinonas/farmacologia , Compostos Fitoquímicos/farmacologia , Psoroptidae/efeitos dos fármacos , Acaricidas/administração & dosagem , Animais , Bioensaio , Sobrevivência Celular/efeitos dos fármacos , Inibidores da Colinesterase/farmacologia , Modelos Animais de Doenças , Glutationa Transferase/antagonistas & inibidores , Infestações por Ácaros/tratamento farmacológico , Naftoquinonas/administração & dosagem , Compostos Fitoquímicos/administração & dosagem , Coelhos , Pele/efeitos dos fármacos , Análise de Sobrevida , Resultado do Tratamento
10.
Food Chem ; 245: 1248-1256, 2018 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-29287349

RESUMO

Cabernet Gernischt (CG) is a famous Chinese wine grape cultivar, the red wine of which is known for its green trait, especially when produced from grapes cultivated in regions with monsoon climate. To modify CG wine aroma, three enzyme preparations (H. uvarum extracellular enzyme, AR2000, and pectinase) were introduced in different winemaking stages with Saccharomyces cerevisiae. Free and bound aroma compounds in young wines were detected using headspace solid-phase micro-extraction and gas chromatography-mass spectrometry, and aroma characteristics were quantified by trained panelists. Results showed that simultaneous inoculation of enzymes and yeasts improved wine aroma. Partial least-squares regression revealed that the green trait was due mainly to varietal compounds, especially C6 compounds, and could be partly weakened by fermentative compounds. Moreover, H. uvarum enzyme treatments enriched the acid fruit note of CG wine by enhancing the synergistic effect of varietal volatiles and certain fermentative compounds, such as esters and phenylethyls.


Assuntos
Enzimas , Manipulação de Alimentos/métodos , Odorantes/análise , Vinho , China , Enzimas/química , Enzimas/metabolismo , Feminino , Fermentação , Cromatografia Gasosa-Espectrometria de Massas/métodos , Glicosídeo Hidrolases/química , Glicosídeo Hidrolases/metabolismo , Hanseniaspora/enzimologia , Humanos , Análise dos Mínimos Quadrados , Masculino , Poligalacturonase/química , Poligalacturonase/metabolismo , Saccharomyces cerevisiae/metabolismo , Microextração em Fase Sólida/métodos , Vitis/química , Vitis/metabolismo , Compostos Orgânicos Voláteis/análise , Vinho/análise
11.
Food Chem ; 245: 667-675, 2018 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-29287424

RESUMO

The effect of regulated deficit irrigation (RDI) on fatty acids and their derived volatiles in 'Cabernet Sauvignon' grapes and wines was investigated during two growing seasons in the east foot of Mt. Helan, the semi-arid area. The vines received water with 60% (RDI-1), 70% (RDI-2), 80% (RDI-3), 100% (CK, traditional drip irrigation) of their estimated evapotranspiration (ETc) respectively. RDI treatments resulted in lower yield, berry weight and titratable acidity with higher total soluble solids. RDI-1 increased the content of unsaturated fatty acids in berries and decreased the level of alcohols and esters volatiles in wines. RDI-2 and RDI-3 enhanced 1-hexanol and esters in wines in comparison with CK. The concentrations of C6 aroma compounds were closely correlated with unsaturated fatty acids (p < .05), especially linolenic acid and linoleic acid. The present results provided direct evidence and detailed data to explain the effect of RDI on grapes and wines composition regarding fatty acids and their derived volatiles.


Assuntos
Irrigação Agrícola/métodos , Ácidos Graxos/metabolismo , Vitis/metabolismo , Vinho/análise , Álcoois/metabolismo , China , Ésteres/análise , Ésteres/metabolismo , Ácidos Graxos/análise , Frutas/química , Frutas/metabolismo , Hexanóis/análise , Hexanóis/metabolismo , Odorantes/análise , Estações do Ano , Vitis/química , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/metabolismo , Água
12.
Bioorg Med Chem Lett ; 27(17): 3959-3962, 2017 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-28789891

RESUMO

In our continuing search for camptothecin (CPT)-derived antitumor drugs, novel 7-substituted CPT derivatives incorporating piperazinyl-sulfonylamidine moieties were designed, synthesized and evaluated for cytotoxicity against five tumor cell lines (A-549, MDA-MB-231, MCF-7, KB, and KB-VIN). All of the derivatives showed promising in vitro cytotoxic activity against the tested tumor cell lines, and were more potent than irinotecan. Remarkably, most of the compounds exhibited comparable cytotoxicity against the multidrug-resistant (MDR) KB-VIN and parental KB tumor cell lines, while irinotecan lost activity completely against KB-VIN. Especially, compounds 13r and 13p (IC50 0.38 and 0.85µM, respectively) displayed the greatest cytotoxicity against the MDR KB-VIN cell line and merit further development into preclinical and clinical drug candidates for treating cancer, including MDR phenotype.


Assuntos
Amidinas/farmacologia , Antineoplásicos/farmacologia , Camptotecina/farmacologia , Desenho de Fármacos , Piperazinas/farmacologia , Amidinas/química , Antineoplásicos/síntese química , Antineoplásicos/química , Camptotecina/síntese química , Camptotecina/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Estrutura Molecular , Piperazina , Piperazinas/química , Relação Estrutura-Atividade
13.
Dalton Trans ; 45(41): 16283-16289, 2016 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-27711799

RESUMO

An acylhydrazone zinc porphyrin P1 and its coordination polymers (CPs, denoted as P1M, M = Mn, Co, Ni, Cu, Zn) with different metal ions (Mn2+, Co2+, Ni2+, Cu2+ and Zn2+) were synthesized. Then these coordination polymers were assembled into bilayer structured supramolecular chromophores through axially coordinating with anchoring porphyrin AP, and their performance in dye sensitized solar cells was investigated. Our results reveal that the bilayer structured supramolecular chromophore based solar cells show significantly improved photocurrent conversion efficiency. Particularly, P1Mn and P1Zn based solar cells showed a relatively higher short circuit current density (JSC) due to their broad absorption bands and remarkable light harvesting abilities. Meanwhile, the VOC values of the cells fabricated with the bilayered chromophores slightly decreased. Electrochemical impedance spectroscopy (EIS) in combination with charge extraction (CE) and transient photovoltage decay (TPD) measurements indicates that the decreased VOC resulted from the vigorous electron recombination and the downward shifted conduction band edge (ECB) of titania.

14.
Yi Chuan ; 38(3): 254-70, 2016 03.
Artigo em Chinês | MEDLINE | ID: mdl-27001479

RESUMO

The WRKY transcription factors are one of the largest families of transcriptional regulators and play diverse regulatory roles in biotic and abiotic stresses, plant growth and development processes. In this study, the WRKY DNA-binding domain (Pfam Database number: PF03106) downloaded from Pfam protein families database was exploited to identify WRKY genes from the peach (Prunus persica 'Lovell') genome using HMMER 3.0. The obtained amino acid sequences were analyzed with DNAMAN 5.0, WebLogo 3, MEGA 5.1, MapInspect and MEME bioinformatics softwares. Totally 61 peach WRKY genes were found in the peach genome. Our phylogenetic analysis revealed that peach WRKY genes were classified into three Groups: Ⅰ, Ⅱ and Ⅲ. The WRKY N-terminal and C-terminal domains of Group Ⅰ (group I-N and group I-C) were monophyletic. The Group Ⅱ was sub-divided into five distinct clades (groupⅡ-a, Ⅱ-b, Ⅱ-c, Ⅱ-d and Ⅱ-e). Our domain analysis indicated that the WRKY regions contained a highly conserved heptapeptide stretch WRKYGQK at its N-terminus followed by a zinc-finger motif. The chromosome mapping analysis showed that peach WRKY genes were distributed with different densities over 8 chromosomes. The intron-exon structure analysis revealed that structures of the WRKY gene were highly conserved in the peach. The conserved motif analysis showed that the conserved motifs 1, 2 and 3, which specify the WRKY domain, were observed in all peach WRKY proteins, motif 5 as the unknown domain was observed in group Ⅱ-d, two WRKY domains were assigned to GroupⅠ. SqRT-PCR and qRT-PCR results indicated that 16 PpWRKY genes were expressed in roots, stems, leaves, flowers and fruits at various expression levels. Our analysis thus identified the PpWRKY gene families, and future functional studies are needed to reveal its specific roles.


Assuntos
Genoma de Planta , Família Multigênica , Proteínas de Plantas/genética , Prunus persica/genética , Fatores de Transcrição/genética , Motivos de Aminoácidos , Sequência de Aminoácidos , Evolução Molecular , Regulação da Expressão Gênica de Plantas , Dados de Sequência Molecular , Filogenia , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Plantas/química , Plantas/classificação , Plantas/genética , Estrutura Terciária de Proteína , Prunus persica/química , Prunus persica/classificação , Prunus persica/metabolismo , Alinhamento de Sequência , Fatores de Transcrição/química , Fatores de Transcrição/metabolismo
15.
G3 (Bethesda) ; 4(8): 1445-53, 2014 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-24898708

RESUMO

The fungal pathogen Cochliobolus carbonum (anamorph, Bipolaris zeicola) causes Northern Leaf Spot, leading to a ubiquitous and devastating foliar disease of corn in Yunnan Province, China. Asexual spores (conidia) play a major role in both epidemics and pathogenesis of Northern Leaf Spot, but the molecular mechanism of conidiation in C. carbonum has remained elusive. Here, using a map-based cloning strategy, we cloned a single dominant gene, designated as BZcon1 (for Bipolaris zeicola conidiation), which encodes a predicted unknown protein containing 402 amino acids, with two common conserved SANT/Myb domains in N-terminal. The BZcon1 knockout mutant completely lost the capability to produce conidiophores and conidia but displayed no effect on hyphal growth and sexual reproduction. The introduced BZcon1 gene fully complemented the BZcon1 null mutation, restoring the capability for sporulation. These data suggested that the BZcon1 gene is essential for the conidiation of C. carbonum.


Assuntos
Ascomicetos/genética , Genes Fúngicos , Esporos Fúngicos/genética , Sequência de Aminoácidos , Ascomicetos/fisiologia , Passeio de Cromossomo , Cromossomos Artificiais Bacterianos , DNA Fúngico , Escherichia coli/genética , Micélio/metabolismo , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos
16.
Phys Rev Lett ; 110(9): 093901, 2013 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-23496710

RESUMO

Optical diodes controlling the flow of light are of principal significance for optical information processing. They transmit light from an input to an output, but not in the reverse direction. This breaking of time reversal symmetry is conventionally achieved via Faraday or nonlinear effects. For applications in a quantum network, features such as the abilities of all-optical control, on-chip integration, and single-photon operation are important. Here we propose an all-optical optical diode which requires neither magnetic fields nor strong input fields. It is based on a "moving" photonic crystal generated in a three-level electromagnetically induced transparency medium in which the refractive index of a weak probe is modulated by the moving periodic intensity of a strong standing coupling field with two detuned counterpropagating components. Because of the Doppler effect, the frequency range of the crystal's band gap for the probe copropagating with the moving crystal is shifted from that for the counterpropagating probe. This mechanism is experimentally demonstrated in a room temperature Cs vapor cell.

17.
Hepatology ; 55(6): 1840-51, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22223166

RESUMO

UNLABELLED: Hepatocellular carcinoma (HCC) is a particularly lethal form of cancer, yet effective therapeutic options for advanced HCC are limited. The poly(ADP-ribose) polymerases (PARPs) and histone deacetylases (HDACs) are emerging to be among the most promising targets in cancer therapy, and sensitivity to PARP inhibition depends on homologous recombination (HR) deficiency and inhibition of HDAC activity blocks the HR pathway. Here, we tested the hypothesis that cotargeting both enzymatic activities could synergistically inhibit HCC growth and defined the molecular determinants of sensitivity to both enzyme inhibitors. We discovered that HCC cells have differential sensitivity to the HDAC inhibitor suberoylanilide hydroxamic acid (SAHA) and PARP inhibitor olaparib, and identified one pair of cell lines, termed SNU-398 and SNU-449, with sensitive versus resistant phenotype to both enzyme inhibitors, respectively. Coadministration of SAHA and olaparib synergistically inhibited the growth of SNU-398 but not SNU-449 cells, which was associated with increased apoptosis and accumulated unrepaired DNA damage. Multiple lines of evidence demonstrate that the hepatic fibrosis/hepatic stellate cell activation may be an important genetic determinant of cellular sensitivity to both enzymatic inhibitors, and coordinate activation or inactivation of the aryl hydrocarbon receptor (AhR) and cyclic adenosine monophosphate (cAMP)-mediated signaling pathways are involved in cell response to SAHA and olaparib treatment. CONCLUSION: These findings suggest that combination therapy with both enzyme inhibitors may be a strategy for therapy of sensitive HCC cells, and identification of these novel molecular determinants may eventually guide the optimal use of PARP and HDAC inhibitors in the clinic.


Assuntos
Carcinoma Hepatocelular/tratamento farmacológico , Inibidores de Histona Desacetilases/farmacologia , Ácidos Hidroxâmicos/farmacologia , Neoplasias Hepáticas/tratamento farmacológico , Ftalazinas/farmacologia , Piperazinas/farmacologia , Inibidores de Poli(ADP-Ribose) Polimerases , Apoptose/efeitos dos fármacos , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , AMP Cíclico/fisiologia , Dano ao DNA , Resistencia a Medicamentos Antineoplásicos , Sinergismo Farmacológico , Células Estreladas do Fígado/efeitos dos fármacos , Humanos , Neoplasias Hepáticas/patologia , Receptores de Hidrocarboneto Arílico/fisiologia , Vorinostat
18.
Proc Natl Acad Sci U S A ; 108(21): 8791-6, 2011 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-21555589

RESUMO

Although metastasis-associated protein 1 (MTA1), a component of the nucleosome remodeling and histone deacetylation complex, is widely up-regulated in human cancers and correlates with tumor metastasis, its regulatory mechanism and related signaling pathways remain unknown. Here, we report a previously unrecognized bidirectional autoregulatory loop between MTA1 and tumor suppressor alternative reading frame (ARF). MTA1 transactivates ARF transcription by recruiting the transcription factor c-Jun onto the ARF promoter in a p53-independent manner. ARF, in turn, negatively regulates MTA1 expression independently of p53 and c-Myc. In this context, ARF interacts with transcription factor specificity protein 1 (SP1) and promotes its proteasomal degradation by enhancing its interaction with proteasome subunit regulatory particle ATPase 6, thereby abrogating the ability of SP1 to stimulate MTA1 transcription. ARF also physically associates with MTA1 and affects its protein stability. Thus, MTA1-mediated activation of ARF and ARF-mediated functional inhibition of MTA1 represent a p53-independent bidirectional autoregulatory mechanism in which these two opposites act in concert to regulate cell homeostasis and oncogenesis, depending on the cellular context and the environment.


Assuntos
Inibidor p16 de Quinase Dependente de Ciclina/genética , Histona Desacetilases/genética , Homeostase/genética , Neoplasias/etiologia , Proteínas Repressoras/genética , Linhagem Celular , Inibidor p16 de Quinase Dependente de Ciclina/antagonistas & inibidores , Inibidor p16 de Quinase Dependente de Ciclina/metabolismo , Regulação da Expressão Gênica , Histona Desacetilases/metabolismo , Humanos , Fases de Leitura , Proteínas Repressoras/antagonistas & inibidores , Proteínas Repressoras/metabolismo , Transativadores , Ativação Transcricional , Proteína Supressora de Tumor p53
19.
Zhonghua Xin Xue Guan Bing Za Zhi ; 39(1): 79-83, 2011 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-21418804

RESUMO

OBJECTIVE: To establish an animal model of congenital heart defect with decreased pulmonary blood flow for better understanding the pathophysiology of pulmonary vascular development and related regulatory mechanisms of congenital heart defect with decreased pulmonary blood flow. METHOD: One to two months old pigs were randomly divided into three groups: control group (group C, n = 6) with right chest small incisions induced transient pulmonary blood reduction; light-moderate stenosis groups (group T(1), n = 7): artificial atrial septum defect (ASD) plus controlled pulmonary artery banding to generate a systolic pressure gradient of 20 - 30 mm Hg (1 mm Hg = 0.133 kPa); severe stenosis groups (group T(2), n = 7): similar surgical procedures as group T(1), and controlled pulmonary artery banding to generate a systolic pressure gradient ≥ 30 - 50 mm Hg. 64-slice computed tomography scanning was performed at one month post operation. Arterial blood gas analysis, hemoglobin value, pulmonary vessel, ASD and banding ring diameters and trans-pulmonary artery banding pressure (Trans-PABP) were determined at two months post operation. RESULTS: One pig died due to tracheal intubation accident in the C group, one pig died due to bowel obstruction in the T(1) group and two pigs died due to acute right heart failure and chronic heart failure respectively in T(2) group. 64-slice CT angiography results showed that aortic diameter of T(1) group was significantly lower than that of C group and banding diameter was significantly lower than aortic diameter in the T(1) and T(2) groups at one month post operation. Two months after operation, the size of ASD were (8.0 ± 0.5) mm and (8.9 ± 1.4) mm (P > 0.05) respectively in the T(1) and T(2) groups after operation. The Trans-PABP was significantly higher in the T(1) and T(2) groups than in C group (P < 0.01), and the Trans-PABP was significantly higher in the T(2) group than in T(1) group (P < 0.01). PaO2 and SaO2 in the T(1) and T(2) groups were significantly lower than those in C group. CONCLUSION: Artificial atrial septum defect combined pulmonary artery banding procedures could be successfully used to establish model of congenital heart defect with decreased pulmonary blood flow and this model could help to understand the pathophysiology and monitor therapy efficacy for patients with congenital heart defect with decreased pulmonary blood flow.


Assuntos
Modelos Animais de Doenças , Cardiopatias Congênitas/fisiopatologia , Artéria Pulmonar/fisiopatologia , Circulação Pulmonar , Animais , Pulmão/irrigação sanguínea , Veias Pulmonares/fisiopatologia , Suínos
20.
Opt Lett ; 34(10): 1510-2, 2009 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-19448804

RESUMO

The Dirac point (DP) with a double-cone structure for optical fields can be realized in optically homogenous media. The condition for the realization of DP in optical systems is the varying of refractive index from negative to zero and then to positive. Our analysis verify that, similar to electrons in graphene, the light field near DP possesses of the pseudodiffusive property obeying the 1/L scaling law, where L is the propagation distance inside the media.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...