摘要：
The photosensitive resveratrol was successfully encapsulated in yeast cells for the first time, as characterized by FT-IR spectra, fluorescence and confocal micrographs of the yeast cells, resveratrol and microcapsules. The release characteristic of the obtained yeast-encapsulated resveratrol in simulated gastric fluid was evaluated, and its storage stability as a powder was investigated at 25 degrees C/75% relative humidity (RH), 25 degrees C/90% RH and 60 degrees C under the laboratory fluorescent lighting conditions (ca. 300 lx) or in the dark. Also, the scavenging capacity of yeast-encapsulated resveratrol on DPPH radical was compared with that of non-encapsulated resveratrol. It could be demonstrated clearly that no chemical changes occurred during the encapsulation. Besides, the DPPH radical-scavenging activity increased after the encapsulation. In addition, the yeast-encapsulated resveratrol exhibited good stability, and its bioavailability was enhanced as a result of increased solubility of resveratrol and sustained releasing. (c) 2007 Elsevier B.V. All rights reserved.
摘要：
SummaryImprovement of drought tolerance in plants depends upon understanding their molecular responses to dehydration stress. The drought resistance of 14 varieties of tall fescue (Festuca arundinacea Schreb.) was analysed by measuring various physiological traits under high temperature and drought conditions. A dehydration-responsive element-binding-2 (DREB2) homologue cDNA from the cultivar ‘Plantation’, with high drought tolerance, designated FapDREB2, was isolated and sequenced. The FapDREB2 cDNA was predicted to encode a protein of 262 amino acid residues, with a molecular mass of 41.3 kDa and a pI of 5.28. Its deduced protein sequence, with a conserved AP2 DNA-binding domain, shared characteristics with the DREB2 gene family based on sequence homology, structure and phylogenetic analysis. Expression of the FapDREB2 gene in different plant organs indicated that its transcripts were abundant in leaves and leaf sheaths, and scarce in roots. In addition, FapDREB2 gene expression under drought and high temperature conditions was stronger than without such treatments in the laboratory. FapDREB2 mRNA accumulated in response to various abiotic stresses, confirming that its expression was induced more prominently by drought or salt treatment than by cold stress, and did not respond to abscisic acid (ABA) treatment. FapDREB2 gene expression in seedlings grown in a study plot varied irregularly under drought and high temperature conditions, in contrast to seedlings grown with drought treatment in the laboratory. This suggests that expression of the DREB2 transcription factor would be complex during plant responses to different stresses. We concluded that the FapDREB2 gene is involved in plant responses to drought or salt stress through an ABA-independent pathway, which may lead to a better understanding of the regulatory mechanism of the DREB2 transcription factor in tall fescue.
