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1.
Plant Dis ; 103(8): 1889-1901, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31161920

RESUMO

Apple fruit spot disease has caused serious economic losses for years in China since the widespread application of fruit bagging in production. Although the three genera Trichothecium, Alternaria, and Acremonium have been reported to be the causal agents, studies on the disease etiology and pathogen biology are still sparse. Here, we report characterization of eight fungal isolates from lesions on 126 symptomatic fruit samples collected in Shaanxi Province, China. Pathogenicity of the isolates was assessed. DNA sequences were obtained at four loci, including D1/D2 domains of the large-subunit nrRNA gene, internal transcribed spacer regions 1 and 2, 5.8S nrDAN gene, a fragment of the actin gene, and a fragment of the ß-tubulin. Based on phylogenetic analysis and morphological features, three new species were found: Acremonium mali, Sarocladium liquanensis, and Sarocladium mali. In addition, we made the first report of Sarocladium terricola as a plant pathogen. Temperature and moisture significantly affected in vitro conidial germination of five Acremonium-like species, and their impact on infection of apple fruit was tested using Acremonium sclerotigenum. Conidia of five species germinated from 15 to 35°C in free water; four of the species had optimum temperature around 25°C, whereas conidia of S. terricola had an optimum temperature of 30°C. Conidial germination rate increased as relative humidity (RH) increased. The five isolates had relatively high conidial germination rates at RH > 97%, with a significant decline at 95% RH. Incidence of infection also increased in proportion to RH. In free water, conidial germination was relatively unaffected by temperature.


Assuntos
Acremonium , Ascomicetos , Frutas , Malus , Acremonium/classificação , Acremonium/fisiologia , Ascomicetos/classificação , Ascomicetos/fisiologia , China , Frutas/microbiologia , Malus/microbiologia , Filogenia , Temperatura
2.
Genet Mol Res ; 14(2): 5699-709, 2015 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-26125769

RESUMO

Three-dimensional ultrasound speckle tracking imaging was used to evaluate the effects of recombinant human brain natriuretic peptide (rhBNP) in acute anterior and extensive anterior myocardial infarction. Ninety patients with acute anterior or extensive myocardial infarction were randomly divided into 3 groups: Group A [emergency percutaneous coronary intervention (PCI)], Group B (emergency PCI + rhBNP early treatment), and Group C (emergency PCI + late rhBNP treatment). Within 6 h of admission and at 1 week and 3 and 6 months after PCI, patients underwent routine transthoracic echocardiography and real-time three-dimensional echocardiography. At 1 week, 1 month, 3 months, 6 months, and 12 months, ejection fraction values in groups B and C were significantly greater than those in group A (P < 0.05), and left ventricular end-diastolic volume and left ventricular end-systolic volume values in groups B and C were less than those in group A (P < 0.05). Within 6 h of admission in each group, long-axis, radial, circumferential, and area variables corresponding to anterior descending artery segments showed no significant difference (all P > 0.05). However, at 1 week, 1 month, 3 months, 6 months, and 12 months, long-axis, radial, circumferential and area variables in groups B and C were significantly less than those in group A (P < 0.05). Intervention with rhBNP can im-prove resilience of the local myocardium, left ventricular mechanical function, and cardiac remodeling. Within 6 h of admission or after PCI, rhBNP application showed no significant difference in heart function improvement or myocardial remodeling inhibition.


Assuntos
Infarto Miocárdico de Parede Anterior/tratamento farmacológico , Peptídeo Natriurético Encefálico/administração & dosagem , Proteínas Recombinantes/administração & dosagem , Função Ventricular/efeitos dos fármacos , Adulto , Idoso , Infarto Miocárdico de Parede Anterior/diagnóstico por imagem , Infarto Miocárdico de Parede Anterior/genética , Infarto Miocárdico de Parede Anterior/patologia , Infarto Miocárdico de Parede Anterior/cirurgia , Ecocardiografia Tridimensional , Feminino , Humanos , Imageamento Tridimensional , Masculino , Pessoa de Meia-Idade , Peptídeo Natriurético Encefálico/genética , Radiografia , Proteínas Recombinantes/genética , Função Ventricular/genética
3.
Bull Entomol Res ; 104(6): 742-50, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25208627

RESUMO

Rhynchophorus ferrugineus (Coleoptera, Curculionidae) is the most destructive pest of palm trees worldwide containing it invasive areas, such as the southern part of China. It is always emphasized to develop integrated pest management based on biological agents, but their success is not very exciting. Presently, the immune defenses of this pest against biological agents attract scarce attention. It is still unclear whether immune priming also generally occurs in insect pests and in response to different pathogens. Our results indicated that previous challenge of bacteria pathogen enhanced the magnitude of phenoloxidase activity and antibacterial activity in R. ferrugineus larvae against the secondary infection. Furthermore, trans-generational immune priming was also determined in this pest, and only challenged R. ferrugineus mothers transferred the immune protection to their offspring which suggested males and females of this pest might have evolved different strategies on the investment of delivering immune protection to their offspring. Importantly, our data provide the evidence to suggest that different kinds of biological control agents might be used alternatively or in combination to fight against R. ferrugineus because of the existence of immune priming with low species-specific level. On the other hand, for this invasive pest, the immune priming may also facilitate its adaptation and dispersal in the new regions.


Assuntos
Gorgulhos/imunologia , Gorgulhos/microbiologia , Animais , Escherichia coli/fisiologia , Feminino , Imunidade Inata , Larva/imunologia , Larva/microbiologia , Masculino , Gorgulhos/crescimento & desenvolvimento
4.
Eur Rev Med Pharmacol Sci ; 17(12): 1583-9, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23832722

RESUMO

BACKGROUND: Coronary chronic total occlusion (CTO) is the end stage of coronary artery atherosclerosis. CTO revascularization can be performed by percutaneous transluminal coronary angioplasty (PTCA), bare metal stent (BMS) or drug-eluting stent (DES). It is important to scientifically evaluate the effectiveness of CTO interventional treatments. METHODS: Relevant studies of long term outcomes for several kinds of CTO treatments were examined. Data were extracted and assessed by two independent clinical experts, pooled and analyzed using meta-analysis. RESULTS: (1) Totally 8 articles comparing outcomes between PTCA and BMS treatment were analyzed. Follow-up variables such as mortality, subsequent coronary artery bypass graft surgery (CABG), re-occlusion, re-stenosis and target lesion revascularization (TLR) were analyzed by meta-analysis. Compared with BMS intervention, PTCA was associated with significant higher rate of re-occlusion, re-stenosis, subsequent PTCA and TLR. (2) Totally 12 articles compared long term outcomes between BMS groups and DES groups, encompassed 3605 CTO patients. During the long-term follow-up, six variables as major adverse cardiac events (MACE), myocardial infarction, all-cause death, subsequent CABG, accumulated MACE-free survival rate, re-stenosis/re-occlusion rate were analyzed by meta-analysis. Compared with patients in DES groups, patients in BMS groups had significant higher MACE, subsequent CABG, re-stenosis/re-occlusion rate, TLR, target vessel revascularization, while lower MACE-free survival rate. CONCLUSIONS: Incidence of re-occlusion, re-stenosis, subsequent PTCA and TLR were significantly lower for BMS implantation than for PTCA procedure. Variables, including MACE, subsequent CABG, re-stenosis/re-occlusion rate were higher while accumulated MACE-free survival rate was lower in BMS groups than in DES groups.


Assuntos
Oclusão Coronária/cirurgia , Angioplastia Coronária com Balão , Humanos , Stents
5.
Rev Sci Instrum ; 94(3): 033508, 2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-37012805

RESUMO

The fast-ion D-alpha diagnostic (FIDA) is employed to detect Dα light emitted by neutralized fast ions during neutral beam injection. A tangentially viewing FIDA has been developed for the HuanLiuqi-2A (HL-2A) tokamak and typically achieves temporal and transverse spatial resolutions of ∼30 ms and ∼5 cm, respectively. A fast-ion tail on the red shifted wing of the FIDA spectrum is obtained and analyzed with the Monte Carlo code FIDASIM. Good agreement has been presented between the measured and simulated spectra. As the FIDA diagnostic's lines of sight intersect the central axis of neutral beam injection with small angles, the beam emission spectrum is observed with a large Doppler shift. Thus, tangentially viewing FIDA could detect only a small portion of fast ions with an energy of ≈ 20 ∼ 31 keV and a pitch angle of ≈ -1 ∼ -0.8. A second FIDA installation with oblique viewing is designed to minimize spectral contaminants.

6.
Mol Psychiatry ; 16(5): 548-56, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-20386566

RESUMO

We report the first genome-wide association study in 1000 bipolar I patients and 1000 controls, with a replication of the top hits in another 409 cases and 1000 controls in the Han Chinese population. Four regions with most strongly associated single-nucleotide polymorphisms (SNPs) were detected, of which three were not found in previous GWA studies in the Caucasian populations. Among them, SNPs close to specificity protein 8 (SP8) and ST8 α-N-acetyl- neuraminide α-2,8-sialyltransferase (ST8SIA2) are associated with Bipolar I, with P-values of 4.87 × 10(-7) (rs2709736) and 6.05 × 10(-6) (rs8040009), respectively. We have also identified SNPs in potassium channel tetramerization domain containing 12 gene (KCTD12) (rs2073831, P=9.74 × 10(-6)) and in CACNB2 (Calcium channel, voltage-dependent, ß-2 subunit) gene (rs11013860, P=5.15 × 10(-5)), One SNP nearby the rs1938526 SNP of ANK3 gene and another SNP nearby the SNP rs11720452 in chromosome 3 reported in previous GWA studies also showed suggestive association in this study (P=6.55 × 10(-5) and P=1.48 × 10(-5), respectively). This may suggest that there are common and population-specific susceptibility genes for bipolar I disorder.


Assuntos
Transtorno Bipolar/etnologia , Transtorno Bipolar/genética , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Polimorfismo de Nucleotídeo Único/genética , Anquirinas/genética , Povo Asiático/etnologia , Povo Asiático/genética , Transtorno Bipolar/epidemiologia , Canais de Cálcio Tipo L/genética , Proteínas de Ligação a DNA/genética , Feminino , Genótipo , Humanos , Masculino , Razão de Chances , Fenótipo , Proteínas/genética , Reprodutibilidade dos Testes , Sialiltransferases/genética , Fatores de Transcrição/genética
7.
Rev Sci Instrum ; 93(11): 113507, 2022 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-36461440

RESUMO

A new neutral particle analyzer (NPA) diagnostic based on single crystal chemical vapor deposition (sCVD) diamond detector that provides measurements of fast ions has been designed and installed on HL-2A tokamak. Diamond detectors have been applied in some magnetic confinement fusion devices due to their outstanding properties of compact size and radiation hardness. This DNPA can measure energies above 13.4 keV. The line of sight (LOS) of the DNPA intersects with the NBI No. 2 with a tangency radius of 154.8 cm. Due to the pitch angle defined by the LOS and geometry of the diagnostic, the DNPA is mainly sensitive to trapped ions. To interpret the energy spectrum and verify the feasibility of the design of the DNPA, a Monte Carlo code called FIDASIM, which is a synthetic diagnostic code that simulates fast ion D-alpha and NPA signals, is applied to model the neutral flux reaching the detector. The results show that the flux is mainly contributed by the low energy fast ions (E < 10 keV) and it is mainly coming from the active components, the passive signal is dominant in the high energy region (E > 15 keV). The modeling features the ability to distinguish between active and passive signals, and the simulated strong passive signals are suggested to come from charge exchange between cold neutrals and fast ions around the plasma edge. In addition, despite the large ratio of halo neutrals, essentially it has a limited contribution to the energy spectrum.

8.
Eur Rev Med Pharmacol Sci ; 25(18): 5610-5618, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34604953

RESUMO

OBJECTIVE: This study aims to explore the biological roles of long non-coding RNA (lncRNA) ZNF281 and KLF15 in regulating cervical carcinoma progression. PATIENTS AND METHODS: Differential expressions of ZNF281 in 58 collected cervical carcinoma and normal tissues were detected by quantitative real-time polymerase chain reaction (qRT-PCR). The relationship between ZNF281 and clinicopathologic characteristics in cervical carcinoma patients was analyzed. By generating ZNF281 knockdown model in HeLa and SiHa cells through the transfection of shZNF281, migratory ability changes were examined via transwell and wound healing assay. The role of ZNF281 in in vivo tumorgenicity of cervical carcinoma was examined by implanting xenografted cancers in nude mice. The downstream target of ZNF281 and their interaction were assessed by bioinformatics tool and Dual-Luciferase reporter assay, respectively. Finally, co-regulations of ZNF281 and KLF15 on cervical carcinoma progression were elucidated. RESULTS: ZNF281 was upregulated in cervical carcinoma tissues and cell lines. It was correlated to TNM staging, and incidences of lymphatic metastasis and distant metastasis in cervical carcinoma patients, while it was unrelated to age and tumor size. The knockdown of ZNF281 effectively attenuated migratory ability in HeLa and SiHa cells. Besides, knockdown of ZNF281 also reduced tumorigenicity of cervical carcinoma in nude mice. KLF15 was the downstream gene binding ZNF281, and they were negatively correlated to each other in cervical carcinoma tissues. Notably, KLF15 was responsible for ZNF281-induced regulation on cervical carcinoma migration. CONCLUSIONS: LncRNA ZNF281 is upregulated in cervical carcinoma samples, and it is correlated to lymphatic metastasis, distant metastasis, and poor prognosis in cervical carcinoma patients. By targeting KLF15, ZNF281 triggers migratory potential in cervical carcinoma. We believed that ZNF281 is a promising biomarker for cervical carcinoma.


Assuntos
Regulação Neoplásica da Expressão Gênica/genética , Fatores de Transcrição Kruppel-Like/metabolismo , Fatores de Transcrição Kruppel-Like/fisiologia , RNA Longo não Codificante/metabolismo , RNA Longo não Codificante/fisiologia , Proteínas Repressoras/metabolismo , Proteínas Repressoras/fisiologia , Neoplasias do Colo do Útero/genética , Animais , Carcinogênese/genética , Linhagem Celular Tumoral , Movimento Celular/genética , Progressão da Doença , Feminino , Células HeLa , Humanos , Metástase Linfática/genética , Camundongos Nus , Ligação Proteica/genética , Neoplasias do Colo do Útero/patologia
9.
Trends Biochem Sci ; 24(8): 295-8, 1999 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10431171

RESUMO

The tRNAs are central components in translation. In addition, they are essential for replication of retroviruses: tRNAs bind to viral genomes through their 3'-end sequences and act as primers for initiation of viral replication. Here, I discuss the possibility that tRNAs also play a role in the horizontal transfer of bacterial pathogenicity islands between different pathogens. Such a role would implicate tRNAs in DNA recombination.


Assuntos
Bactérias/genética , Bactérias/patogenicidade , RNA Bacteriano/genética , RNA de Transferência/genética , Sequência de Bases , Transferência Genética Horizontal , Modelos Biológicos , Recombinação Genética , Virulência/genética
10.
Trends Biochem Sci ; 14(6): 233-7, 1989 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-2669241

RESUMO

The recognition of transfer RNAs (tRNAs) by aminoacyl tRNA synthetases establishes the connection between amino acids and trinucleotides. However, for E. coli alanine tRNA the trinucleotide sequence which specifies alanine is not important for recognition. Instead a single base pair is a major determinant for the identity of this tRNA. Even a synthetic RNA microhelix with seven base pairs can be aminoacylated if it includes the major determinant.


Assuntos
Alanina/metabolismo , Anticódon , Escherichia coli/genética , RNA de Transferência de Alanina/genética , RNA de Transferência Aminoácido-Específico/genética , RNA de Transferência , Aminoacil-tRNA Sintetases/metabolismo , Sequência de Bases , Evolução Biológica , Cinética , Dados de Sequência Molecular , Conformação de Ácido Nucleico
11.
Nucleic Acids Res ; 29(4): 976-85, 2001 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-11160931

RESUMO

We have investigated the role of 2'-OH groups in the specific interaction between the acceptor stem of Escherichia coli tRNA(Cys) and cysteine-tRNA synthetase. This interaction provides for the high aminoacylation specificity observed for cysteine-tRNA synthetase. A synthetic RNA microhelix that recapitulates the sequence of the acceptor stem was used as a substrate and variants containing systematic replacement of the 2'-OH by 2'-deoxy or 2'-O-methyl groups were tested. Except for position U73, all substitutions had little effect on aminoacylation. Interestingly, the deoxy substitution at position U73 had no effect on aminoacylation, but the 2'-O-methyl substitution decreased aminoacylation by 10-fold and addition of the even bulkier 2'-O-propyl group decreased aminoacylation by another 2-fold. The lack of an effect by the deoxy substitution suggests that the hydrogen bonding potential of the 2'-OH at position U73 is unimportant for aminoacylation. The decrease in activity upon alkyl substitution suggests that the 2'-OH group instead provides a monitor of the steric environment during the RNA-synthetase interaction. The steric role was confirmed in the context of a reconstituted tRNA and is consistent with the observation that the U73 base is the single most important determinant for aminoacylation and therefore is a site that is likely to be in close contact with cysteine-tRNA synthetase. A steric role is supported by an NMR-based structural model of the acceptor stem, together with biochemical studies of a closely related microhelix. This role suggests that the U73 binding site for cysteine-tRNA synthetase is sterically optimized to accommodate a 2'-OH group in the backbone, but that the hydroxyl group itself is not involved in specific hydrogen bonding interactions.


Assuntos
Aminoacil-tRNA Sintetases/metabolismo , Escherichia coli/enzimologia , Escherichia coli/genética , RNA de Transferência de Cisteína/química , RNA de Transferência de Cisteína/metabolismo , Proteínas de Ligação a RNA/metabolismo , Acilação , Aminoacil-tRNA Sintetases/química , Aminoacil-tRNA Sintetases/genética , Bacillus subtilis/genética , Sequência de Bases , Cisteína/metabolismo , Ligação de Hidrogênio , Cinética , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Dados de Sequência Molecular , Estrutura Molecular , Conformação de Ácido Nucleico , Oligorribonucleotídeos/química , Oligorribonucleotídeos/genética , Oligorribonucleotídeos/metabolismo , RNA Bacteriano/química , RNA Bacteriano/genética , RNA Bacteriano/metabolismo , RNA de Transferência de Cisteína/genética , Proteínas de Ligação a RNA/química , Proteínas de Ligação a RNA/genética , Uridina/análogos & derivados , Uridina/química , Uridina/metabolismo
12.
Nucleic Acids Res ; 27(24): 4743-50, 1999 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-10572174

RESUMO

The core region of Escherichia coli tRNA(Cys)is important for aminoacylation of the tRNA. This core contains an unusual G15:G48 base pair, and three adenosine nucleotides A13, A22 and A46 that are likely to form a 46:[13:22] adenosine base triple. We recently observed that the 15:48 base pair and the proposed 46:[13:22] triple are structurally and functionally coupled to contribute to aminoacylation. Inspection of a database of tRNA sequences shows that these elements are only found in one other tRNA, the Haemophilus influenzae tRNA(Cys). Because of the complexity of the core, conservation of sequence does not mean conservation of function. We here tested whether the conserved elements in H. influenzae tRNA(Cys)were also important for aminoacylation of H. influenzae tRNA(Cys). We cloned and purified a recombinant H. influenzae cysteine-tRNA synthe-tase and showed that it depends on 15:48 and 13, 22 and 46 in a relationship analogous to that of E. coli cysteine-tRNA synthetase. The functional conservation of the tRNA core is correlated with sequence conservation between E.coli and H.influenzae cysteine-tRNA synthetases. As the genome of H. influenzae is one of the smallest and may approximate a small autonomous entity in the development of life, the dependence of this genome on G15:G48 and its coupling with the proposed A46:[A13:A22] triple for aminoacylation with cysteine suggests an early role of these motifs in the evolution of decoding genetic information.


Assuntos
Aminoacil-tRNA Sintetases/genética , Escherichia coli/genética , Haemophilus influenzae/genética , RNA de Transferência de Cisteína/química , RNA de Transferência de Cisteína/genética , Acilação , Adenina , Sequência de Aminoácidos , Aminoacil-tRNA Sintetases/química , Aminoacil-tRNA Sintetases/metabolismo , Bactérias/enzimologia , Bactérias/genética , Pareamento de Bases , Sequência de Bases , Sequência Conservada , Evolução Molecular , Humanos , Dados de Sequência Molecular , Conformação de Ácido Nucleico , Filogenia , RNA Bacteriano/química , RNA Bacteriano/genética , Saccharomyces cerevisiae/enzimologia , Saccharomyces cerevisiae/genética , Schizosaccharomyces/enzimologia , Schizosaccharomyces/genética , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Transcrição Gênica
13.
Rev Sci Instrum ; 87(11): 11D429, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27910502

RESUMO

A filterscope diagnostic system has been mounted to observe the line emission and visible bremsstrahlung emission from plasma on the experimental advanced superconducting tokamak during the 2014 campaign. By this diagnostic system, multiple wavelengths including Dα (656.1 nm), Dγ (433.9 nm), He ii (468.5 nm), Li i (670.8 nm), Li ii (548.3 nm), C iii (465.0 nm), O ii (441.5 nm), Mo i (386.4 nm), W i (400.9 nm), and visible bremsstrahlung radiation (538.0 nm) are monitored with corresponding wavelength filters. All these multi-channel signals are digitized at up to 200 kHz simultaneously. This diagnostic plays a crucial role in studying edge localized modes and H-mode plasmas, due to the high temporal resolution and spatial resolution that have been designed into it.

14.
Rev Sci Instrum ; 87(11): 11D616, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27910316

RESUMO

Volume recombination plays an important role towards plasma detachment for magnetically confined fusion devices. High quantum number states of the Balmer series of deuterium are used to study recombination. On EAST (Experimental Advanced Superconducting Tokamak), two visible spectroscopic measurements are applied for the upper/lower divertor with 13 channels, respectively. Both systems are coupled with Princeton Instruments ProEM EMCCD 1024B camera: one is equipped on an Acton SP2750 spectrometer, which has a high spectral resolution ∼0.0049 nm with 2400 gr/mm grating to measure the Dα(Hα) spectral line and with 1200 gr/mm grating to measure deuterium molecular Fulcher band emissions and another is equipped on IsoPlane SCT320 using 600 gr/mm to measure high-n Balmer series emission lines, allowing us to study volume recombination on EAST and to obtain the related line averaged plasma parameters (Te, ne) during EAST detached phases. This paper will present the details of the measurements and the characteristics of deuterium Balmer series line emissions during density ramp-up L-mode USN plasma on EAST.

15.
Rev Sci Instrum ; 87(11): 11E542, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27910390

RESUMO

To investigate the fast ion behavior, a fast ion D-alpha (FIDA) diagnostic system has been installed on EAST. Fast ion features can be inferred from the Doppler shifted spectrum of Balmer-alpha light from energetic hydrogenic atoms. This paper will focus on the validation of FIDA measurements performed using MHD-quiescent discharges in 2015 campaign. Two codes have been applied to calculate the Dα spectrum: one is a Monte Carlo code, Fortran 90 version FIDASIM, and the other is an analytical code, Simulation of Spectra (SOS). The predicted SOS fast-ion spectrum agrees well with the measurement; however, the level of fast-ion part from FIDASIM is lower. The discrepancy is possibly due to the difference between FIDASIM and SOS velocity distribution function. The details will be presented in the paper to primarily address comparisons of predicted and observed spectrum shapes/amplitudes.

16.
Rev Sci Instrum ; 87(11): 11E552, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27910605

RESUMO

In toroidal magnetic fusion devices, fast-ion D-alpha diagnostic (FIDA) is a powerful method to study the fast-ion feature. The fast-ion characteristics can be inferred from the Doppler shifted spectrum of Dα light according to charge exchange recombination process between fast ions and probe beam. Since conceptual design presented in the last HTPD conference, significant progress has been made to apply FIDA systems on the Experimental Advanced Superconducting Tokamak (EAST). Both co-current and counter-current neutral beam injectors are available, and each can deliver 2-4 MW beam power with 50-80 keV beam energy. Presently, two sets of high throughput spectrometer systems have been installed on EAST, allowing to capture passing and trapped fast-ion characteristics simultaneously, using Kaiser HoloSpec transmission grating spectrometer and Bunkoukeiki FLP-200 volume phase holographic spectrometer coupled with Princeton Instruments ProEM 1024B eXcelon and Andor DU-888 iXon3 1024 CCD camera, respectively. This paper will present the details of the hardware descriptions and experimental spectrum.

17.
Biochim Biophys Acta ; 951(1): 230-4, 1988 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-3056525

RESUMO

The cDNA of mouse metallothionein, a small metal-binding protein rich in cysteine, has been cloned downstream from a bacterial inducible promoter and expressed in Escherichia coli. Upon induction, E. coli harboring this cDNA clone contained a protein species readily labelled by [35S]cysteine in vivo and incorporated 10-times as much 109Cd from the medium than would otherwise be the case. We show that expression of metallothionein endows resistance in E. coli to heavy metal ions such as mercury, silver, copper, cadmium and zinc by sequestering rather than exclusion or conversion, common mechanisms of metal resistance in bacteria.


Assuntos
Escherichia coli/genética , Metalotioneína/genética , Metais/farmacologia , Animais , Cádmio/farmacologia , Cobre/farmacologia , DNA/genética , Sondas de DNA , Resistência Microbiana a Medicamentos/genética , Eletroforese em Gel de Poliacrilamida , Escherichia coli/efeitos dos fármacos , Regulação da Expressão Gênica , Mercúrio/farmacologia , Camundongos , Plasmídeos , RNA Mensageiro/genética , Prata/farmacologia , Transformação Genética , Zinco/farmacologia
18.
J Mol Biol ; 295(4): 777-89, 2000 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-10656790

RESUMO

The contribution of the tRNA "core" to aminoacylation is beginning to be recognized. One example is the core region of Escherichia coli tRNA(Cys), which has been shown by biochemical studies to be important for aminoacylation. This core has several layers of unusual base-pairs, which are revealed by the recent crystal structure of the tRNA complexed with the elongation factor EF-Tu and an analog of GTP. One of these layers consists of a 9:[13:22] base-triple, rather than the 46:[13:22] or 45:[13:22] base-triple that is commonly observed in tRNA structure. Because 13:22 is an important element in aminoacylation of E. coli tRNA(Cys), a better understanding of its structure in the tRNA core will shed light on its role in aminoacylation. In this study, we used the phage T7 transcript of the tRNA as a substrate. We probed the structure of 13:22 by dimethyl sulfate and tested its partner in a base-triple by generating mutations that could be assayed for aminoacylation. The results of this study in general are in a better agreement with a 46:[13:22] base-triple that we previously proposed. Although these results are not interpreted as direct proof for the 46:[13:22] base-triple, they shed new light on features of the tRNA core that are important for aminoacylation.


Assuntos
Escherichia coli/genética , Conformação de Ácido Nucleico , RNA de Transferência de Cisteína/química , RNA de Transferência de Cisteína/metabolismo , Pareamento de Bases , Sequência de Bases , Cisteína/metabolismo , Escherichia coli/metabolismo , Humanos , Ligação de Hidrogênio , Modelos Moleculares , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , RNA Bacteriano/química , RNA Bacteriano/metabolismo , RNA Fúngico/química , Saccharomyces cerevisiae/genética , Ésteres do Ácido Sulfúrico , Transcrição Gênica
19.
J Mol Biol ; 303(4): 503-14, 2000 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-11054287

RESUMO

The core of Escherichia coli tRNA(Cys) is important for aminoacylation of the tRNA by cysteine-tRNA synthetase. This core differs from the common tRNA core by having a G15:G48, rather than a G15:C48 base-pair. Substitution of G15:G48 with G15:C48 decreases the catalytic efficiency of aminoacylation by two orders of magnitude. This indicates that the design of the core is not compatible with G15:C48. However, the core of E. coli tRNA(Gln), which contains G15:C48, is functional for cysteine-tRNA synthetase. Here, guided by the core of E. coli tRNA(Gln), we sought to test and identify alternative functional design of the tRNA(Cys) core that contains G15:C48. Although analysis of the crystal structure of tRNA(Cys) and tRNA(Gln) implicated long-range tertiary base-pairs above and below G15:G48 as important for a functional core, we showed that this was not the case. The replacement of tertiary interactions involving 9, 21, and 59 in tRNA(Cys) with those in tRNA(Gln) did not construct a functional core that contained G15:C48. In contrast, substitution of nucleotides in the variable loop adjacent to 48 of the 15:48 base-pair created functional cores. Modeling studies of a functional core suggests that the re-constructed core arose from enhanced stacking interactions that compensated for the disruption caused by the G15:C48 base-pair. The repacked tRNA core displayed features that were distinct from those of the wild-type and provided evidence that stacking interactions are alternative means than long-range tertiary base-pairs to a functional core for aminoacylation.


Assuntos
Aminoacil-tRNA Sintetases/metabolismo , Escherichia coli/genética , Mutação/genética , Conformação de Ácido Nucleico , RNA de Transferência de Cisteína/química , RNA de Transferência de Cisteína/metabolismo , Acilação , Anticódon/genética , Pareamento de Bases/genética , Sequência de Bases , Escherichia coli/enzimologia , Cinética , Modelos Moleculares , Dados de Sequência Molecular , RNA Bacteriano/química , RNA Bacteriano/genética , RNA Bacteriano/metabolismo , RNA de Transferência de Cisteína/genética , RNA de Transferência de Glutamina/química , RNA de Transferência de Glutamina/genética , Especificidade por Substrato , Ésteres do Ácido Sulfúrico/metabolismo , Termodinâmica
20.
J Mol Biol ; 299(2): 431-46, 2000 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-10860750

RESUMO

The position of the tertiary Levitt pair between nucleotides 15 and 48 in the transfer RNA core region suggests a key role in stabilizing the joining of the two helical domains, and in maintaining the relative orientations of the D and variable loops. E. coli tRNA(Gln) possesses the canonical Pu15-Py48 trans pairing at this position (G15-C48), while the tRNA(Cys) species from this organism instead features an unusual G15-G48 pair. To explore the structural context dependence of a G15-G48 Levitt pair, a number of tRNA(Gln) species containing G15-G48 were constructed and evaluated as substrates for glutaminyl and cysteinyl-tRNA synthetases. The glutaminylation efficiencies of these mutant tRNAs are reduced by two to tenfold compared with native tRNA(Gln), consistent with previous findings that the tertiary core of this tRNA plays a role in GlnRS recognition. Introduction of tRNA(Cys) identity nucleotides at the acceptor and anticodon ends of tRNA(Gln) produced a tRNA substrate which was efficiently aminoacylated by CysRS, even though the tertiary core region of this species contains the tRNA(Gln) G15-C48 pair. Surprisingly, introduction of G15-G48 into the non-cognate tRNA(Gln) tertiary core then significantly impairs CysRS recognition. By contrast, previous work has shown that CysRS aminoacylates tRNA(Cys) core regions containing G15-G48 with much better efficiency than those with G15-C48. Therefore, tertiary nucleotides surrounding the Levitt pair must significantly modulate the efficiency of aminoacylation by CysRS. To explore the detailed nature of the structural interdependence, crystal structures of two tRNA(Gln) mutants containing G15-G48 were determined bound to GlnRS. These structures show that the larger purine ring of G48 is accommodated by rotation into the syn position, with the N7 nitrogen serving as hydrogen bond acceptor from several groups of G15. The G15-G48 conformations differ significantly compared to that observed in the native tRNA(Cys) structure bound to EF-Tu, further implicating an important role for surrounding nucleotides in maintaining the integrity of the tertiary core and its consequent ability to present crucial recognition determinants to aminoacyl-tRNA synthetases.


Assuntos
Aminoacil-tRNA Sintetases/metabolismo , Escherichia coli/enzimologia , Escherichia coli/genética , Conformação de Ácido Nucleico , RNA de Transferência/química , RNA de Transferência/metabolismo , Aminoacil-tRNA Sintetases/química , Pareamento de Bases/genética , Sequência de Bases , Sítios de Ligação , Catálise , Cristalização , Cristalografia por Raios X , Ligação de Hidrogênio , Cinética , Modelos Moleculares , Dados de Sequência Molecular , Mutação/genética , Estabilidade de RNA , RNA Bacteriano/química , RNA Bacteriano/genética , RNA Bacteriano/metabolismo , RNA de Transferência/genética , RNA de Transferência de Cisteína/química , RNA de Transferência de Cisteína/genética , RNA de Transferência de Cisteína/metabolismo , RNA de Transferência de Glutamina/química , RNA de Transferência de Glutamina/genética , RNA de Transferência de Glutamina/metabolismo , Proteínas de Ligação a RNA/química , Proteínas de Ligação a RNA/metabolismo , Alinhamento de Sequência , Especificidade por Substrato
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