葡萄白藜芦醇合成酶基因的克隆

为了构建白藜芦醇合成酶(RS)基因的克隆载体,用PCR技术从葡萄叶片总DNA中扩增出RS基因全长,然后将其重组到克隆载体中。通过酶切对重组质粒进行了鉴定和测序,结果表明,RS基因已经正确克隆至pUC19中,将重组质粒转入大肠杆菌里,使RS基因能够在大肠杆菌里保存并且大量扩增,为RS基因构建表达载体表达白藜芦醇合成酶奠定了基础。     

白藜芦醇合酶的研究进展

白藜芦醇是一种重要的植物抗毒素,具有多种医疗保健作用,因此其应用前景 非常广泛,已引起多方关注。白藜芦醇合酶是白藜芦醇生物合成途径中的关键酶之一,它催化1分子4-香豆酰辅酶A和3分子丙二酰辅酶A反应合成白藜芦醇,它是白藜芦醇生物合成中惟一必需的酶,关于它的研究已广泛开展起来。本文综述了白藜芦醇的药理活性、白藜芦醇合 酶的酶学性质、诱导途径和机制以及分子生物学方面的研究进展。     

基因枪法在水稻工程育种中的应用

至今,基因枪法以其实用性和有效性应用于水稻工程育种已有十几年,本文阐述了其在水稻工程育种的六个主要领域的应用现状,同时评价了外源基因在转基因水稻中的稳定性和对转基因水稻主要农艺性状的影响。当然,基因枪法的转化效率还有待提高,随着转不同基因的工程水稻的日益增多,进一步的安全性试验显得十分必要,它是转基因水稻商品化的前提。     

烟酰胺合成酶基因在植物铁胁迫应答反应中的功能

铁离子在植物的生理生化代谢中具有重要的功能.缺铁和铁过量都会对植物造成伤害,因此,维持植物铁离子的动态平衡具有很重要的作用.烟酰胺合成酶基因(NAS)与植物铁离子的吸收转运关系非常密切,但在机理Ⅰ型和机理Ⅱ型植物中,NAS基因的作用机理和表达模式却不同.在双子叶和非禾本科单子叶植物中,烟酰胺(NA)的主要功能是铁离子的储藏和运输,NAS基因的表达不受缺铁胁迫诱导.而在禾本科植物中,NAS基因的表达受缺铁胁迫诱导,并且与铁元素的吸收关系密切.     

彩色小麦种质资源在生物强化和功能食品应用中的研究进展北大核心CSCD

因为人类膳食不平衡和微量营养缺乏导致的隐性饥饿已经受到国内外高度重视。利用生物育种技术培育富含各种微量营养的优良作物品种是生物强化和功能食品的主要发展方向。国内外大量研究表明,彩色小麦种质资源富含花青素、铁、锌、硒、维生素、叶酸等微量营养和蛋白质等,对抗炎、抗癌、糖尿病、心脑血管疾病、贫血病、生长发育不良等有一定的功效,将在保障粮食安全和人类健康中发挥重要作用。本研究首先介绍了隐性饥饿、生物强化、功能食品、功能农业和功能品种等方面的发展趋势,重点介绍了国内外彩色小麦种质资源功能营养成分及遗传育种方面的研究进展。建议广泛收集和创制彩色功能营养小麦新种质,挖掘优异营养基因资源,揭示彩色小麦花青素和微量营养(硒、锌、铬等微量元素,维生素,人体不能合成的8种氨基酸,叶酸等)以及品质(蛋白质含量和组分)性状的遗传耦合机理,以期为彩色小麦生物强化和主粮功能化提供理论依据和技术支撑。     

谷氨酸棒杆菌海藻糖合成酶基因的克隆及功能鉴定

利用生物信息学手段,在GenBank数据库进行氨基酸的同源性检索分析,发现来自谷氨酸棒杆茵(Corynebacterium glutamicum)一功能未确定的ORF序列被注释为假设的海藻糖酶(putative trehalose sesynthase),它与已报道的海藻糖合成酶的氨基酸序列有60％以上的同源性。本研究把这段ORF克隆到大肠杆茵进行表达及进行功能鉴定。实验表明这段ORF序列为一新的海藻糖合成酶基因,其表达产物能将麦芽糖分子转化成海藻糖分子。重组酶性质的初步研究表明重组酶在pH7．0～7．5,30℃转化麦芽糖效率最高。     

RNA干扰技术在功能基因研究中的应用

RNA干扰是与靶基因序列同源的双链RNA所诱导的一种特异性的转录后基因沉默现象。它是一种跨越多种种属的古老的生物途径,同时它的出现为生物学家提供了一种快速,简便的反向遗传学技术,在后基因组时代功能基因的研究中具有重要的应用前景。     

灰树花海藻糖合成酶基因的克隆及其在大肠杆菌中的表达

海藻糖主要作用是作为生物体的结构组分、以及保护生物膜和保护蛋白质。在灰树花中 ,海藻糖在干重中所占比例最高可达到 1 5 %～ 1 7% ,说明灰树花合成海藻糖的能力很强。将灰树花海藻糖合成酶基因克隆 ,并在大肠杆菌表达系统里表达。表达量为 1 90mg L。通过活性测定 ,证明在大肠杆菌中表达的海藻糖合成酶具有酶活性 ,结合基因工程和酶工程方法 ,为合成海藻糖的研究提供了新的方向     

植物纤维素合成酶基因的研究进展

纤维素是植物细胞壁的主要成分。自然界中每年大约有1800亿吨的纤维素产物生成。纤维素的巨大经济价值使纤维素合成酶基因成为基因工程的热点之一。1996年, Delmer小组首次从植物中克隆出纤维素合成酶基因。近年来,在纤维素合成酶的结构、功能、定位和基因功能的研究方面成果斐然。本文概述了植物纤维素合成酶基因的研究进展。 Abstract:Cellulose is a major component in plant cell wall.About 180 billion tons of cellulose are produced per year in nature.The commercial importance of cellulose makes the genes coding it one of attractive targets for plant genetic engineering.A number of cellulose synthase genes have been first cloned from plant species by Delmer's group in 1996.Recently,research achievement has been obtained in accumulating to understanding the cellulose synthase function,location,and the gene function.The paper summarized the research progress of cellulose synthase genes in higher plants.     

白藜芦醇的研究进展

白藜芦醇是一种含有芪类结构的非黄酮类多酚化合物.它不仅是植物遭受胁迫时产生的一种能提高植物抵抗病原性攻击和环境恶化的植物抗毒素,还具有抗癌,抗氧化、调节血脂,影响寿命等多方面有益于人类健康的重要功能.以下对白藜芦醇的理化特性、合成、提取、纯化与检测方法进行了全面总结,并在其作用的分子机制基础上,对其生物学活性、基因工程研究及产业化情况进行了重点介绍.发现在传统育种的基础上,借助于现代生物技术手段,将白藜芦醇的天然活性保健作用应用于保健食品的开发、作物经济附加值的提高具有广阔的前景.它的开发和利用,必将为食品及制药工业新产品的开发提供新的挑战与机遇.     

An ozone-responsive region of the grapevine resveratrol synthase promoter differs from the basal pathogen-responsive sequence

Plant Molecular Biology - Stilbene synthase (STS) is an enzyme involved in the biosynthesis of stilbenes, which are synthesized in various plants in response to pathogen attack, UV irradiation or...     

Ozone- and ethylene-induced regulation of a grapevine resveratrol synthase promoter in transgenic tobacco

Stilbene synthases (STSs) are enzymes that play a critical role in the biosynthesis of stilbene, phytoalexins in a small number of unrelated plant species, and are induced by various biotic and abiotic stressors like pathogen attack, UV-irradiation or ozone exposure. To investigate the molecular basis for ozone-induced plant stress responses, we have examined the promoter of the grapevine resveratrol synthase (Vst1). In this report we summarize the influence of ozone on gene regulation. In transgenic tobacco a chimeric gene construct, containing the Vst1 promoter combined with the β-glucuronidase (GUS) reporter gene, is rapidly induced by ozone (0.1 μl·l⁻¹, 12 h). The same construct is also strongly induced by ethylene (20 μl·l⁻¹, 12 h). Promoter deletion analysis of the 5′ flanking sequence identified a positive regulatory element between −430 bp and −280 bp. This region contains ethylene-responsive enhancer elements, as well as an elicitor-responsive sequence in inverse orientation.     

Expression of a stilbene synthase gene in Nicotiana tabacum results in synthesis of the phytoalexin resveratrol

A gene from groundnut (Arachis hypogaea) coding for stilbene synthase was transferred together with a chimaeric kanamycin resistance gene. It was found to be rapidly expressed after induction with UV light and elicitor in tobacco cells (Nicotiana tabacum). Comparative studies of stilbene synthase mRNA synthesis in groudnut and transgenic tobacco suspension cultures revealed the same kinetics of gene expression. Stilbene synthase specific mRNA was detectable 30 minutes after elicitor induction and 10 minutes after UV irradiation. The maximum of mRNA accumulation was between 2 and 8 hours post induction. 24 hours after induction stilbene synthase mRNA accumulation ceased. Furthermore, in transgenic tobacco plants, the gene was found to be inducible in sterile roots, stems and leaves. Stilbene synthase was demonstrated in crude protein extracts from transgenic tobacco cell cultures using specific antibodies. Resveratrol, the product of stilbene synthase, was identified by HPLC and antisera raised against resveratrol.     

前列腺素内过氧化物合酶2基因的研究进展

前列腺素内过氧化物合酶2是前列腺素生物合成的限速酶。本文介绍了前列腺素内过氧化物合酶2基因的结构、表达、调控机理及其与繁殖性能的关系。     

Analysis of the sucrose synthase gene family in Arabidopsis

The properties and expression patterns of the six isoforms of sucrose synthase in Arabidopsis are described, and their functions are explored through analysis of T-DNA insertion mutants. The isoforms have generally similar kinetic properties. Although there is variation in sensitivity to substrate inhibition by fructose this is unlikely to be of major physiological significance. No two isoforms have the same spatial and temporal expression patterns. Some are highly expressed in specific locations, whereas others are more generally expressed. More than one isoform is expressed in all organs examined. Mutant plants lacking individual isoforms have no obvious growth phenotypes, and are not significantly different from wild-type plants in starch, sugar and cellulose content, seed weight or seed composition under the growth conditions employed. Double mutants lacking the pairs of similar isoforms sus2 and sus3, and sus5 and sus6, are also not significantly different in these respects from wild-type plants. These results are surprising in the light of the marked phenotypes observed when individual isoforms are eliminated in crop plants including pea, maize, potato and cotton. A sus1/sus4 double mutant grows normally in well-aerated conditions, but shows marked growth retardation and accumulation of sugars when roots are subjected to hypoxia. The sucrose synthase activity in roots of this mutant is 3% or less of wild-type activity. Thus under well-aerated conditions sucrose mobilization in the root can proceed almost entirely via invertases without obvious detriment to the plant, but under hypoxia there is a specific requirement for sucrose synthase activity.     

Expression of a chimeric stilbene synthase gene in transgenic wheat lines

A chimeric stilbene synthase (sts)gene was transferred into wheat. Stilbene synthases play a role in the defence against fungal diseases in some plant species (e.g. groundnut or grapevine) by producing stilbenetype phytoalexins like resveratrol. Resveratrol is also claimed to have positive effects to human health. Embryogenic scutellar calli derived from immature embryos of the two commercial German spring wheat cultivars Combi and Hanno were used as target tissue for cotransformation by microprojectile delivery. The selectable marker/reporter gene constructs contained the bargene either driven by the ubiquitinpromoter from maize (pAHC 25, also containing the uidAgene driven by the ubiquitinpromoter), or by the actinpromoter (pDM 302) from rice. The cotransferred plasmid pStil 2 consisted of a grapevine stscoding region driven by the ubiquitin promoter. Eight transgenic Combi and one Hanno T_Oplant were obtained and, except one Combi T_Oplant, found to be cotransformants due to the integration of both the stsgene and the selectable marker or reporter genes. Expression of the stsgene was proven by RTPCR, and, for the first time, by detection of the stilbene synthase product resveratrol by HPLC and mass spectrometry. The stsgene was expressed in four of the seven transgenic Combi T_{_o}plants. Two of the respective T₁progenies segregated in a Mendelian manner were still expressing the gene. Investigations into methylation of the stsgene showed that in three nonexpressing progenies inactivation was paralleled by methylation.     

植物类型III聚酮合酶超家族基因结构、功能及代谢产物

植物聚酮类化合物主要包括酚类、芪类及类黄酮化合物等,在植物花色、防止紫外线伤害、预防病原菌、昆虫危害以及作为植物与环境互作信号分子方面行使着重要的生物学功能。该类化合物具有显著多样的生物学活性,对人体保健及疾病治疗有显著意义。植物类型III 聚酮化合物合酶 (PKS) 在该类化合物生物合成起始反应中行使着关键作用,决定该类化合物基本分子骨架建成和代谢途径碳硫走向,为合成途径关键酶和限速酶。以查尔酮合酶为原型酶的植物类型III PKS超家族是研究系统进化和蛋白结构与功能关系的模式分子家族,目前已经分离得到14种植物类型III PKS基因,这些同祖同源基因及其表达产物既有共性,也表现出许多独特个性,这些个性赋予此类次生代谢产物结构上的多样性。以下综述了植物类型III PKS超家族基因结构、功能及代谢产物研究进展。     

All members in the sphingomyelin synthase gene family have ceramide phosphoethanolamine synthase activity

Sphingomyelin synthase-related protein (SMSr) synthesizes the sphingomyelin analog ceramide phosphoethanolamine (CPE) in cells. Previous cell studies indicated that SMSr is involved in ceramide homeostasis and is crucial for cell function. To further examine SMSr function in vivo, we generated Smsr KO mice that were fertile and had no obvious phenotypic alterations. Quantitative MS analyses of plasma, liver, and macrophages from the KO mice revealed only marginal changes in CPE and ceramide as well as other sphingolipid levels. Because SMS2 also has CPE synthase activity, we prepared Smsr/Sms2 double KO mice. We found that CPE levels were not significantly changed in macrophages, suggesting that CPE levels are not exclusively dependent on SMSr and SMS2 activities. We then measured CPE levels in Sms1 KO mice and found that Sms1 deficiency also reduced plasma CPE levels. Importantly, we found that expression of Sms1 or Sms2 in SF9 insect cells significantly increased not only SM but also CPE formation, indicating that SMS1 also has CPE synthase activity. Moreover, we measured CPE synthase K_m and V_max for SMS1, SMS2, and SMSr using different NBD ceramides. Our study reveals that all mouse SMS family members (SMSr, SMS1, and SMS2) have CPE synthase activity. However, neither CPE nor SMSr appears to be a critical regulator of ceramide levels in vivo.