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1.
Nanotechnology ; 30(43): 435202, 2019 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-31304918

RESUMO

AlGaN-based deep ultraviolet (DUV) multiple-quantum-wells (MQWs) incorporating strain-modulated nanostructures are proposed, demonstrating enhanced degree of polarization (DOP) and improved light extraction efficiency (LEE). The influence of Al composition and bi-axial strains on the optical behaviors of the DUV-MQWs were carefully examined. Compared with planar DUV-MQWs, strain-modulated nanostructure patterned MQWs show three times higher photoluminescence and increased DOP from -0.43 to -0.16. Moreover, nanostructure patterned DUV-MQWs under compressive strains further illustrate higher DOP and LEE values than those under tensile strains due to more efficient diffraction of the guided modes of the transverse electric (TE) polarized light. Our work demonstrates, for the first time, that a combination of compressive in-plane strain and surface nanostructure show unambiguous advantages in facilitating TE mode emission, thus have great promises in the design and optimization of highly efficient polarized DUV optoelectronic devices.

2.
Opt Express ; 27(11): 16195-16205, 2019 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-31163803

RESUMO

The optical properties of hexagonal GaN microdisk arrays grown on sapphire substrates by selective area growth (SAG) technique were investigated both experimentally and theoretically. Whispering-gallery-mode (WGM) lasing is observed from various directions of the GaN pyramids collected at room temperature, with the dominant lasing mode being Transverse-Electric (TE) polarized. A relaxation of compressive strain in the lateral overgrown region of the GaN microdisk is illustrated by photoluminescence (PL) mapping and Raman spectroscopy. A strong correlation between the crystalline quality and lasing behavior of the GaN microdisks was also demonstrated.

3.
Oxid Med Cell Longev ; 2019: 3685817, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31210839

RESUMO

Purpose: Prostate cancer (PC) is a common malignant tumor and a leading cause of cancer-related death in men worldwide. In order to design new therapeutic interventions for PC, an understanding of the molecular events underlying PC tumorigenesis is required. Bloom syndrome protein (BLM) is a RecQ-like helicase, which helps maintain genetic stability. BLM dysfunction has been implicated in tumor development, most recently during PC tumorigenesis. However, the molecular basis for BLM-induced PC progression remains poorly characterized. In this study, we investigated whether BLM modulates the phosphorylation of an array of prooncogenic signaling pathways to promote PC progression. Methods: We analyzed differentially expressed proteins (DEPs) using iTRAQ technology. Site-directed knockout of BLM in PC-3 prostate cancer cells was performed using CRISPR/Cas9-mediated homologous recombination gene editing to confirm the effects of BLM on DEPs. PathScan® Antibody Array Kits were used to analyze the phosphorylation of nodal proteins in PC tissue. Immunohistochemistry and automated western blot (WES) analyses were used to validate these findings. Results: We found that silencing BLM in PC-3 cells significantly reduced their proliferative capacity. In addition, BLM downregulation significantly reduced levels of phosphorylated protein kinase B (AKT (Ser473)) and proline-rich AKT substrate of 40 kDa (PRAS40 (Thr246)), and this was accompanied by enhanced ROS (reactive oxygen species) levels. In addition, we found that AKT and PRAS40 inhibition reduced BLM, increased ROS levels, and induced PC cell apoptosis. Conclusions: We demonstrated that BLM activates AKT and PRAS40 to promote PC cell proliferation and survival. We further propose that ROS act in concert with BLM to facilitate PC oncogenesis, potentially via further enhancing AKT signaling and downregulating PTEN expression. Importantly, inhibiting the BLM-AKT-PRAS40 axis induced PC cell apoptosis. Thus, we highlight new avenues for novel anti-PC treatments.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/biossíntese , Proliferação de Células , Regulação Neoplásica da Expressão Gênica , Neoplasias da Próstata/metabolismo , Proteínas Proto-Oncogênicas c-akt/biossíntese , RecQ Helicases/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Sobrevivência Celular , Humanos , Masculino , Células PC-3 , Neoplasias da Próstata/genética , Neoplasias da Próstata/patologia , Proteínas Proto-Oncogênicas c-akt/genética , Espécies Reativas de Oxigênio/metabolismo , RecQ Helicases/genética
4.
Mol Med Rep ; 19(6): 4819-4831, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30957187

RESUMO

BLM RecQ like helicase (BLM) has a pivotal role in genetic recombination, transcription, DNA replication and DNA repair, which presents the possibility of using BLM as an anti­cancer target for treatment. However, the post­transcriptional control regulation of BLM gene expression is not fully understood and limits the application of drugs targeting BLM for carcinoma therapy in the future. MicroRNAs (miRNAs) inhibit gene expression through interaction with the 3' untranslated region (3'­UTR) of mRNA at the post­transcriptional stage. Therefore, the current study screened for miRNAs that regulate BLM gene expression, with software predicting that miRNA (miR)­27b­3p, miR­607, miR­361­3p, miR­628­5p and miR­338­3p. BLM gene expression levels in the PC3 prostate cancer cell line and RWPE­2 normal prostate epithelium cell line were detected by reverse transcription­quantitative PCR. Additionally, BLM mRNA levels were following miRNA overexpression for 24 and 48 h. For further miRNA filtration and validation, a dual­luciferase reporter system and western blot analysis were performed, which demonstrated that miR­27b­3p and miR­607 reduce BLM gene expression by directly targeting the BLM mRNA 3'­UTR. A Box­Behnken design experiment suggested that miR­27b­3p and miR­607 have synergetic mutual effects on BLM gene expression. Finally, the suppressive effect of miR­27b­3p and miR­607 on PC3 cell proliferation, colony formation, migration and invasion indicated the benefit of studying BLM as a drug target in cancer. In conclusion, the findings of the current provide evidence that miR­27b­3p and miR­607 have an oncosuppressive function in PC3 cells and cooperatively downregulate BLM expression at the post­transcriptional level.


Assuntos
Regiões 3' não Traduzidas/genética , Regulação da Expressão Gênica , MicroRNAs/genética , RecQ Helicases/genética , Movimento Celular , Proliferação de Células , Ensaio de Unidades Formadoras de Colônias , Humanos , MicroRNAs/metabolismo , Mutação , Células PC-3 , RNA Mensageiro/metabolismo , Deleção de Sequência
5.
Nanotechnology ; 29(45): 45LT01, 2018 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-30160239

RESUMO

Enhanced photoluminescence and improved internal quantum efficiency were demonstrated for ultraviolet light emitting diodes (UV-LEDs) with Al nanohole arrays deposited on the top surface. The effects of the thickness and periodicity of the plasmonic structures on the optical properties of UV-LEDs were studied, and an optimized nanohole array parameter was illustrated. Classical electrodynamic simulations showed that the radiated power is mostly concentrated along the edge of the Al nanohole arrays. Even though no obvious dip was observed in the transmission spectra associated with localized surface plasmon resonance, significant improvements in radiatiative recombination and light extraction efficiency were demonstrated, indicating the influence of Al nanohole arrays on the light emission control of UV-LEDs. It is anticipated that the enhanced luminescence can be obtained for various emitting wavelengths by directly adjusting the periodicity and morphology of the Al nanohole arrays and this new technology can alleviate crystal quality requirements of III-nitride thin films in the development of high efficiency UV optoelectronic devices.

6.
Virulence ; 9(1): 783-803, 2018 12 31.
Artigo em Inglês | MEDLINE | ID: mdl-29532715

RESUMO

The matrix (M) protein of Newcastle disease virus (NDV) is demonstrated to localize in the nucleus via intrinsic nuclear localization signal (NLS), but cellular proteins involved in the nuclear import of NDV M protein and the role of M's nuclear localization in the replication and pathogenicity of NDV remain unclear. In this study, importin ß1 was screened to interact with NDV M protein by yeast two-hybrid screening. This interaction was subsequently confirmed by co-immunoprecipitation and pull-down assays. In vitro binding studies indicated that the NLS region of M protein and the amino acids 336-433 of importin ß1 that belonged to the RanGTP binding region were important for binding. Importantly, a recombinant virus with M/NLS mutation resulted in a pathotype change of NDV and attenuated viral replication and pathogenicity in chicken fibroblasts and SPF chickens. In agreement with the binding data, nuclear import of NDV M protein in digitonin-permeabilized HeLa cells required both importin ß1 and RanGTP. Interestingly, importin α5 was verified to interact with M protein through binding importin ß1. However, importin ß1 or importin α5 depletion by siRNA resulted in different results, which showed the obviously cytoplasmic or nuclear accumulation of M protein and the remarkably decreased or increased replication ability and pathogenicity of NDV in chicken fibroblasts, respectively. Our findings therefore demonstrate for the first time the nuclear import mechanism of NDV M protein and the negative regulation role of importin α5 in importin ß1-mediated nuclear import of M protein and the replication and pathogenicity of a paramyxovirus.


Assuntos
Transporte Ativo do Núcleo Celular , Fibroblastos/virologia , Carioferinas/metabolismo , Doença de Newcastle/virologia , Vírus da Doença de Newcastle/fisiologia , Proteínas da Matriz Viral/metabolismo , Replicação Viral , Animais , Linhagem Celular , Galinhas , Regulação da Expressão Gênica , Imunoprecipitação , Modelos Biológicos , Mapeamento de Interação de Proteínas , Técnicas do Sistema de Duplo-Híbrido
7.
Arch Biochem Biophys ; 634: 57-68, 2017 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-29017749

RESUMO

Numerous studies have shown that nuclear localization of BLM protein, a member of the RecQ helicases, mediated by nuclear localization signal (NLS) is critical for DNA recombination, replication and transcription, but the mechanism by which BLM protein is imported into the nucleus remains unknown. In this study, the nuclear import pathway for BLM was investigated. We found that nuclear import of BLM was inhibited by two dominant-negative mutants of importin ß1 and NTF2/E42K, which lacks the ability to bind Ran and RanGDP, respectively, but was not inhibited by the Ran/Q69L, which is deficient in GTP hydrolysis. Further studies revealed that nuclear import of BLM was reconstituted using importin ß1, RanGDP and NTF2 in digitonin-permeabilized HeLa cells. Moreover, BLM had direct binding to importin ß1 through its NLS domain with the 14-16 HEAT repeats of importin ß1. Furthermore, importin ß1, Ran or NTF2 depletion by siRNA disrupted the accumulation of BLM protein in the nucleus. These results showed that BLM enters the nucleus via the importin ß1, RanGDP and NTF2 dependent pathway, demonstrating for the first time the nuclear trafficking mechanism of a DNA helicase.


Assuntos
Núcleo Celular/metabolismo , Proteínas de Transporte Nucleocitoplasmático/metabolismo , Proteínas da Gravidez/metabolismo , RecQ Helicases/metabolismo , beta Carioferinas/metabolismo , Proteína ran de Ligação ao GTP/metabolismo , Transporte Ativo do Núcleo Celular/fisiologia , Células HeLa , Humanos , Modelos Biológicos , Transdução de Sinais/fisiologia
8.
Genome Announc ; 4(6)2016 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-27932647

RESUMO

Here, we report the complete genome sequences of two Newcastle disease viruses, Sheldrake duck/China/Guizhou/01/2016 and Sheldrake duck/China/Guizhou/02/2016, isolated from Sansui Sheldrake ducks in Guizhou Province, China. The genome of the isolates is 15,198 nucleotides in length. Phylogenetic analysis revealed that the isolates are clustered into subgenotype 1b in class I.

9.
Genome Announc ; 4(3)2016 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-27174267

RESUMO

Here, we report the complete genome sequence of an H6N6 avian influenza virus (AIV) isolated from Sansui Sheldrake ducks in Guizhou Province, China, in 2014. Phylogenetic analysis showed that the H6N6 virus was a reassortant virus derived from three different H6 subtype lineages. The finding of this study will help us understand the epidemiology and the evolutionary characteristics of H6 subtypes of AIV in ducks in southwestern China.

10.
Int J Mol Sci ; 17(5)2016 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-27164086

RESUMO

Uncoupling protein 3 (UCP3) is mainly expressed in muscle. It plays an important role in muscle, but less research on the regulation of cattle UCP3 has been performed. In order to elucidate whether cattle UCP3 can be regulated by muscle-related factors, deletion of cattle UCP3 promoter was amplified and cloned into pGL3-basic, pGL3-promoter and PEGFP-N3 vector, respectively, then transfected into C2C12 myoblasts cells and UCP3 promoter activity was measured using the dual-Luciferase reporter assay system. The results showed that there is some negative-regulatory element from -620 to -433 bp, and there is some positive-regulatory element between -433 and -385 bp. The fragment (1.08 kb) of UCP3 promoter was cotransfected with muscle-related transcription factor myogenic regulatory factors (MRFs) and myocyte-specific enhancer factor 2A (MEF2A). We found that UCP3 promoter could be upregulated by Myf5, Myf6 and MyoD and downregulated by MyoG and MEF2A.


Assuntos
Bovinos/genética , Fatores de Transcrição MEF2/metabolismo , Fator Regulador Miogênico 5/metabolismo , Regiões Promotoras Genéticas , Proteína Desacopladora 3/genética , Animais , Masculino , Ativação Transcricional , Proteína Desacopladora 3/metabolismo
11.
Future Microbiol ; 10(8): 1307-23, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26234909

RESUMO

Recent advances in recombinant genetic engineering techniques have brought forward a leap in designing new vaccines in modern medicine. One attractive strategy is the application of reverse genetics technology to make recombinant Newcastle disease virus (rNDV) deliver protective antigens of pathogens. In recent years, numerous studies have demonstrated that rNDV-vectored vaccines can induce quicker and better humoral and mucosal immune responses than conventional vaccines and are protective against pathogen challenges. With deeper understanding of NDV molecular biology, it is feasible to develop gene-modified rNDV vaccines accompanied by good safety, high efficacy, low toxicity and better immunogenicity. This review summarizes the development of reverse genetics technology in using NDV as a promising vaccine vector to design new vaccines for human and animal use.


Assuntos
Vetores Genéticos , Vírus da Doença de Newcastle/genética , Vírus da Doença de Newcastle/imunologia , Genética Reversa , Vacinas Sintéticas/imunologia , Vacinas Virais/imunologia , Animais , Controle de Doenças Transmissíveis/métodos , Engenharia Genética , Genoma Viral , Humanos , Imunidade Humoral , Imunidade nas Mucosas , Vacinas Sintéticas/administração & dosagem , Vacinas Virais/administração & dosagem
12.
Genome Announc ; 3(2)2015 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-25858828

RESUMO

In this study, we report the complete genome sequence of a novel Newcastle disease virus (NDV) strain, Sheldrake duck/China/Guizhou/SS1/2014, isolated from Sansui Sheldrake duck flocks in Guizhou Province, southwestern China. The genome of this isolate is 15,192 nucleotides in length, which belongs to NDV genotype VIId in class II. This discovery will help us further study the epidemiology characteristics and molecular pathogenesis of genotype VIId NDV in Sansui Sheldrake ducks.

13.
Biomed Environ Sci ; 24(1): 47-55, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21440839

RESUMO

OBJECTIVE: Bloom's syndrome is an autosomal recessive disorder characterized by genomic instability and a predisposition to many cancers. Mutations of the BLM gene (encoding a BLM helicase) may form a structure of the etiology of this disease. As a global pollutant, mercury poses a major threat to human health. The current study was conducted to elucidate the effects of Hg(2+) on the structure and activity of BLM642-1290 recombinant helicase, and to further explore the molecular mechanisms of mercury toxicity to the DNA helicase. METHODS: The effects of Hg(2+) on biological activity and structure of BLM642-1290 recombinant helicase were determined by fluorescence polarized, ultraviolet spectroscopic, and free-phosphorus assay technologies, respectively. RESULTS: The helicase activity, the DNA-binding activity, and the ATPase activity of BLM642-1290 recombinant helicase were inhibited by Hg(2+) treatment. The LMCT (ligand-to-metal charge transition) peaks of the helicase were enhanced with the increase of the Hg(2+) level. The LMCT peaks of the same concentration of helicase gradually increased over time. CONCLUSION: The biological activity of BLM642-1290 recombinant helicase is inhibited by Hg(2+) treatment. The conformation of the helicase is significantly altered by Hg(2+). There exist two binding sites between Hg(2+) and the helicase, which are located in the amino acid residues 1063-1066 and 940-944 of the helicase, respectively.


Assuntos
Mercúrio/toxicidade , RecQ Helicases/efeitos dos fármacos , Adenosina Trifosfatases/metabolismo , Sequência de Bases , Primers do DNA , Polarização de Fluorescência , Humanos , Conformação Proteica , RecQ Helicases/química , RecQ Helicases/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/efeitos dos fármacos , Proteínas Recombinantes/metabolismo , Espectrofotometria Ultravioleta , Relação Estrutura-Atividade
14.
Biochemistry ; 49(4): 656-68, 2010 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-20028084

RESUMO

Bloom's syndrome (BS) is a rare human autosomal recessive disorder characterized by a strong predisposition to a wide range of cancers commonly affecting the general population. Understanding the functioning mechanism of the BLM protein may provide the opportunity to develop new effective therapy strategies. In this work, we studied the DNA unwinding kinetic mechanism of the helicase core of the BLM protein using various stopped-flow assays. We show that the helicase core of BLM unwinds duplex DNA as monomers even under conditions strongly favoring oligomerization. An unwinding rate of approximately 20 steps per second and a step size of 1 bp have been determined. We have observed that the helicase has a very low processivity. From dissociation and inhibition experiments, we have found that during its ATP hydrolysis cycle in DNA unwinding the helicase tends to dissociate from the DNA substrate in the ADP state. The experimental results imply that the BLM helicase core may unwind duplex DNA in an inchworm manner.


Assuntos
DNA/química , RecQ Helicases/metabolismo , Difosfato de Adenosina/metabolismo , Trifosfato de Adenosina/metabolismo , Sítios de Ligação , Síndrome de Bloom/enzimologia , Síndrome de Bloom/metabolismo , DNA/metabolismo , Dimerização , Humanos , Hidrólise , Cinética , RecQ Helicases/química
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