Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 3 de 3
Filtrar
Mais filtros











Base de dados
Intervalo de ano de publicação
1.
Plant Sci ; 238: 46-52, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26259173

RESUMO

Non-coding RNAs (ncRNAs) regulate gene expression at the transcriptional and post-transcriptional levels. Many ncRNAs have been identified in the past decade, including small ncRNAs, such as microRNAs (miRNAs), and long ncRNAs (lncRNAs). These novel molecules have important roles in a wide range of biological processes such as the regulation of reproduction and sex determination. Due to their ability to regulate specific genes or entire gene families, these molecules have the potential for uses in the development of breeding strategies as well as in the genetic modification of agronomic traits. In this review, we summarize recent progress on the understanding of plant miRNAs and lncRNAs in male and female development. We also discuss future challenges of using these molecules in agricultural applications, including transgenic plants in hybrid breeding, for novel genetic trait selection, for rapid character screening, and genetic modification for crop improvement.


Assuntos
MicroRNAs/metabolismo , Desenvolvimento Vegetal/genética , RNA Longo não Codificante/metabolismo , MicroRNAs/genética , RNA Longo não Codificante/genética , RNA de Plantas/genética , RNA de Plantas/metabolismo , Pequeno RNA não Traduzido/genética , Pequeno RNA não Traduzido/metabolismo , Reprodução/genética
2.
Dalton Trans ; (33): 6593-8, 2009 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-19672503

RESUMO

A series of dysprosium complex doped xerogels with the same first ligand (acac = acetylacetone) and different neutral ligands were synthesized in situ via a sol-gel process. The Fourier transform infrared (FTIR) spectra, diffuse reflectance (DR) spectra, and near-infrared (NIR) luminescent properties of dysprosium complexes and dysprosium complex doped xerogels are described in detail. The results reveal that the dysprosium complex is successfully synthesized in situ in the corresponding xerogel. Excitation at the maximum absorption wavelength of the ligands resulted in the characteristic NIR luminescence of the Dy3+ ion, which contributes to the energy transfer from the ligands to the central Dy3+ ion in both the dysprosium complexes and xerogels via an antenna effect. The NIR luminescent properties of the dysprosium complexes and xerogels were compared, respectively. The evidence showed that the neutral ligand triphenyl phosphine oxide (TPPO) could increase the emission intensity of the dysprosium complex while 1,10-phenanthroline (phen) gave the negative effect. In addition, the coordinated water molecules affect the emission intensity of the dysprosium complex doped xerogel without the neutral ligand.

3.
Phys Chem Chem Phys ; 11(29): 6051-9, 2009 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-19606313

RESUMO

We report a comparative quantum-chemical study of the electronic structures and optical properties of a series of cationic complexes [M(ppy)(2)(N--N)](+) (N--N = Hcmbpy = 4-carboxy-4'-methylbpy, M = Rh (Rh1), Ir(Ir2); N--N = H(2)dcbpy = 4,4'-dicarboxy-bpy, M = Rh (Rh3) and Ir (Ir4)). The theoretical calculation reveals that the increased number of -COOH groups on the bpy ligand can decrease the energy levels of LUMO more than HOMO and narrow down the HOMO-LUMO energy gaps, which results in the red-shifted of the lowest-lying absorption and phosphorescent spectra. The lowest-lying singlet absorptions were categorized as d(M,M = Rh or Ir) + pi(ppy) -->pi*(bpy) with MLCT and LLCT characters. The calculated phosphorescence at 628 and 668 nm for and is mainly bpy-based intraligand pi* -->pi transition, while 743 and 827 nm emission for and are mixed characters of (3)MLCT and (3)LLCT {[pi*(bpy)] --> [d(Ir) + pi(ppy)]}. Moreover, the reasons for different transition characters and phosphorescence quantum yield between Rh and Ir species, and between and are discussed in this paper.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA