作者机构：
[He, Feifei; Chen, Qing; Zhang, Fusuo; Su, Fang; Jiang, Rongfeng] Key Laboratory of Plant-soil Interactions of Ministry of Education, Key Laboratory of Plant Nutrition of Minstry of Agriculture, College of Resources and Environmental Sciences, China Agricultural University, No. 2 Yuanmingyuan West Road, Haidian District, Beijing 100193, China;[He, Feifei] College of Bioscience and Biotechnology, Hunan Agricultural University, Furong District, Changsha 410128, China
通讯机构：
[Su, F.] K;Key Laboratory of Plant-soil Interactions of Ministry of Education, Key Laboratory of Plant Nutrition of Minstry of Agriculture, College of Resources and Environmental Sciences, China Agricultural University, No. 2 Yuanmingyuan West Road, China
摘要：
Laboratory batch experiments were conducted to study arsenic （As） removal from a naturally contaminated soil using phosphoric acid （H_3PO_4） and potassium dihydrogen phosphate （KHEPO_4）. Both H_3PO_4 and KHEPO_4 proved to reduce toxicity of the soil in terms of soil As content, attaining more than 20% As removal at a concentration of 200 mmol/L. At the same time, acidification of soil and dissolution of soil components （Ca, Mg, and Si） resulted from using these two extractants, especially H_3PO_4. The effectiveness of these two extractants could be attributed to the replacement of As by phosphate ions （PO~(3-)_4）. The function of H_3PO_4 as an acid to dissolve soil components had little effects on As removal. KH_2PO_4 almost removed as much As as H_3PO_4, but it did not result in serious damage to soils, indicating that it was a more promising extractant. The results of a kinetic study showed that As removal reached equilibrium after incubation for 360 rain, but dissolution of soil components, especially Mg and Ca, was very rapid. Therefore dissolution of soil components would be inevitable if As was further removed. Elovich model best described the kinetic data of As removal among the four models used in the kinetic study.
摘要：
Shikonin and its derivatives are formed in large amounts in dark-cultured Onosma paniculatum cells. In order to isolate and identify the genes regulating shikonin biosynthesis, we constructed and characterized a full-length-enriched cDNA Library of dark-cultured cells by using the SMART (Switching Mechanism At 5'-end of RNA Transcript) cDNA synthesis and LD-PCR (tong-distance PCR) strategies. The titer of the primary cDNA library was 1.04 x 10(6) pfu/mL with a recombination rate of 99.60%. Most of the cDNA inserts ranged from 1.0 to 2.5 kb, and 78.33% of the 76 randomly selected clones contained full-length coding regions. Expression analysis of randomly selected genes by small scale microarray revealed that 23 genes were down-regulated, including 17 genes with known functions, 2 genes with putative functions, and 4 novel genes, and that 3 genes were up-regulated (two-fold) in cells cultured under white tight as compared with those cultured in the dark. Interestingly, two of the down-regulated genes, encoding aci-reductone dioxygenase (ARD)-like protein and ethylene responsive factor (ERF), are involved in ethylene biosynthesis and signal transduction, implying that ethylene might play an important role as a signal molecule in tight-regulated shikonin formation. These data contribute to a better understanding of light-involvement in regulating the formation of plant secondary metabolites. (C) 2007 Elsevier GmbH. All rights reserved.
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.
摘要：
The transcription factor WRKY70 was previously reported to be a common component in salicylic acid (SA) and jasmonate (JA) mediated signal pathways in Arabidopsis. Here, we present that the inactivation of the WRKY70 gene in wrky70-1 mutant does not alter the responses of both JA and SA, and that wrky70 mutation is unable to restore the coi1 mutant in JA responses. However, overexpression of WRKY70 reduces JA responses such as expression of JA-induced genes and JA-inhibitory root growth, and activates expression of SA-inducible PR1. These data indicate that the WRKY70 is important but not indispensable for JA and SA signaling, and that other regulators may display the redundant role with WRKY70 in modulation of JA and SA responses in Arabidopsis. Furthermore, we showed that JA inhibits expression of WRKY70 and PR1 by both COI1-dependent and COI1-independent pathways.
摘要：
Ubiquitin ligases play a central role in determining the specificity of the ubiquitination system by selecting a myriad of appropriate candidate proteins for modification. The U-box is a recently identified, ubiquitin ligase activity-related protein domain that shows greater presence in plants than in other organisms. In this study, we identified 77 putative U-box proteins from the rice genome using a battery of whole genome analysis algorithms. Most of the U-box protein genes are expressed, as supported by the identification of their corresponding expressed sequence tags (ESTs), full-length cDNAs, or massively parallel signature sequencing (MPSS) tags. Using the same algorithms, we identified 61 U-box proteins from the Arabidopsis genome. The rice and Arabidopsis U-box proteins were classified into nine major classes based on their domain compositions. Comparison between rice and Arabidopsis U-box proteins indicates that the majority of rice and Arabidopsis U-box proteins have the same domain organizations. The inferred phylogeny established the homology between rice and Arabidopsis U-box/ARM proteins. Cell death assay using the rice protoplast system suggests that one rice U-box gene, OsPUB51, might act as a negative regulator of cell death signaling. In addition, the selected U-box proteins were found to be functional E3 ubiquitin ligases. The identification and analysis of rice U-box proteins hereby at the genomic level will help functionally characterize this class of E3 ubiquitin ligase in the future.
作者机构：
[Hao, Xiao-Jiang] Kunming Inst Bot, State Key Lab Phytochem Plant Resource W China, Kunming 650204, Yunnan, Peoples R China.;Hunan Agr Univ, Coll Living Creature Sci & Technol, Changsha 410128, Hunan, Peoples R China.;Hunan Agr Univ, Coll Hort & Landscape, Changsha 410128, Hunan, Peoples R China.
通讯机构：
[Hao, Xiao-Jiang] K;Kunming Inst Bot, State Key Lab Phytochem Plant Resource W China, Kunming 650204, Yunnan, Peoples R China.
关键词：
Cipadessa cinerascens;Tetranortriterpenoids;Triterpenoids;Cipadesin D and E
摘要：
Two new tetranortriterpenoids, cipadesin D (1) and E (2), were isolated from the stems of Cipadessa cinerascens. Their structures were elucidated by analysis of their spectroscopic data.
摘要：
The water-soluble antioxidant, chlorogenic acid, was successfully encapsulated in the low cost-high volume yeast cells for the first time, as characterized by FT-IR spectra and fluorescence micrograph of the yeast cells, chlorogenic acid and microcapsule. The encapsulation efficiency (EE) of yeast cells could be enhanced significantly (P < 0.001) by the treatment of yeast cells with plasmolyser before encapsulation. Also, the release characteristics of the obtained yeast-encapsulated chlorogenic acid were evaluated, and its storage stability as a powder were investigated at 25 degrees C/75% relative humidity (RH), 25 degrees C/90% RH and 60 degrees C. It could be clearly demonstrated that no chemical changes had taken place during the encapsulation, and the yeast-encapsulated chlorogenic acid exhibited a good stability. This study would be helpful to promote the application of chlorogenic acid. The new yeast-cell-based encapsulation protocol may have some general interests for maintaining the stability of other water-soluble substances. (c) 2006 Elsevier Ltd. All rights reserved.
摘要：
The piezoelectric bulk acoustic wave (BAW) impedance analysis method was employed to monitor in situ the proteinase-catalyzed hydrolyzation of casein and the effect of pesticide D-allethrin on the proteinase activity in the midgut of the spider Pardosa pseudoannulata, and the results obtained were verified by ultraviolet spectroscopy. The hydrolyzation was significantly increased in the presence of low-dose D-allethrin, whereas significantly inhibited in the presence of high-dose D-allethrin, and a correlation was found precisely between the enzyme activity reflected by the final frequency shift after the hydrolyzation and the concentration of D-allethrin, with a significant frequency response observed even at a 1.5 × 10-5 volume ratio of D-allethrin to distilled water. The present work may have presented a novel method feasible for study on the mechanism of excitability of spiders under low-dose D-allethrin pesticide and quick detection of proteinase activity.
