Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 2 de 2
Filtrar
Adicionar filtros








Intervalo de ano
1.
Indian J Biochem Biophys ; 2008 Aug; 45(4): 244-9
Artigo em Inglês | IMSEAR | ID: sea-27884

RESUMO

Thylakoid membranes were isolated and purified from diploid filamentous sporophytes of Porphyra yezoensis Ueda using sucrose density gradient ultracentrifugation (SDGUC). After thylakoid membranes were solubilized with SDS, the phtosystem II (PSII) particles with high 2, 6-dichloroindophenol (DCIP) photoreduction activity were isolated by SDGUC. The absorption and fluorescence spectra, DCIP photoreduction activity and oxygen evolution activity of the thylakoid membranes and PSII particles were determined. The polypeptide composition of purified PSII particles was distinguished by SDS-PAGE. Results showed that PSII particles of sporophytes differed from the gametophytes in spectral properties and polypeptide composition. Apart from 55 kDa D1-D2 heterodimer, CP47, CP43, 33 kDa protein, D1, D2, cyt b559 and 12 kDa protein were identified from PSII particles from sporophytes; a new 102 kDa protein was also detected. However, cyt c-550, 20 kDa, 14 kDa and 16 kDa proteins found in PSII particles from gametophytes were not detected in the sporophytes.


Assuntos
2,6-Dicloroindofenol/farmacologia , Dimerização , Eletroforese em Gel de Poliacrilamida , Peso Molecular , Complexo de Proteína do Fotossistema II/química , Porphyra/química , Dodecilsulfato de Sódio/química , Solubilidade , Espectrometria de Fluorescência , Tilacoides/química , Ultracentrifugação
2.
Indian J Biochem Biophys ; 2006 Oct; 43(5): 284-8
Artigo em Inglês | IMSEAR | ID: sea-28884

RESUMO

Astaxanthin, a high-value ketocarotenoid is mainly used in fish aquaculture. It also has potential in human health due to its higher antioxidant capacity than beta-carotene and vitamin E. The unicellular green alga Haematococcus pluvialis is known to accumulate astaxanthin in response to environmental stresses, such as high light intensity and salt stress. Carotenoid hydroxylase plays a key role in astaxanthin biosynthesis in H. pluvialis. In this paper, we report the characterization of a promoter-like region (-378 to -22 bp) of carotenoid hydroxylase gene by cloning, sequence analysis and functional verification of its 919 bp 5'-flanking region in H. pluvialis. The 5'-flanking region was characterized using micro-particle bombardment method and transient expression of LacZ reporter gene. Results of sequence analysis showed that the 5'-flanking region might have putative cis-acting elements, such as ABA (abscisic acid)-responsive element (ABRE), C-repeat/dehydration responsive element (C-repeat/DRE), ethylene-responsive element (ERE), heat-shock element (HSE), wound-responsive element (WUN-motif), gibberellin-responsive element (P-box), MYB-binding site (MBS) etc., except for typical TATA and CCAAT boxes. Results of 5' deletions construct and beta-galactosidase assays revealed that a highest promoter-like region might exist from -378 to -22 bp and some negative regulatory elements might lie in the region from -919 to -378 bp. Results of site-directed mutagenesis of a putative C-repeat/DRE and an ABRE-like motif in the promoter-like region (-378 to -22 bp) indicated that the putative C-repeat/DRE and ABRE-like motif might be important for expression of carotenoid hydroxylase gene.


Assuntos
Clorófitas/enzimologia , Sequência de Bases , Sítios de Ligação , Clonagem Molecular , Deleção de Genes , Óperon Lac , Oxigenases de Função Mista/biossíntese , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Mutação , Plasmídeos/metabolismo , Regiões Promotoras Genéticas
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA