PMI基因为选择标记植物表达载体的构建及在雪柑转基因中的应用

以PMI基因替换植物表达载体pCAMBIA1301中的hpt基因以及pBI121中的GUS基因，构建了以PMI基因为选择标记基因的植物表达载体pCAMBIA1301PMI和pBIPMI，并导入根癌农杆菌EHA105中。研究了两种表达载体对雪柑上胚轴的转化，在培养基附加25 g•L-1甘露糖和5 g•L-1蔗糖为碳源的选择压下，pCAMBIA1301PMI的转化率为27.7％，pBIPMI的转化率为12.7％，对再生植株进行了氯酚红检测和PCR检测，建立了以PMI/甘露糖为选择系统的雪柑转基因体系。     

PMI基因作为选择标记的植物表达载体构建及其在雪柑转基因中的应用

以大肠杆菌(Escherichia coli)6-磷酸甘露糖异构酶(6-phosphomannose isomerase,PMI)基因替换植物表达载体pCAMBIA1301中的hpt基因以及pBI121中的gus基因,构建了以PMI基因为选择标记基因的植物表达载体pCAMBIA1301PMI和pBIPMI,并导人根癌农杆菌(Agrobacterium tumefaciens)EHA105中.研究了两种表达载体对雪柑(Citrus sinensis L.Osbeck)上胚轴的转化,在培养基附加25 g/L甘露糖和5 g/L蔗糖为碳源的选择压力下,pCAMBIA1301PMI的转化率为27.7%,pBIPMI转化率为12.7%,对再生植株用氯酚红和PCR检测证实了PMI基因的导入,建立了以PMI/甘露糖为选择系统的雪柑转基因体系.     

玉米Ubi-1启动子驱动挪威鼠Hspa4基因植物表达载体的构建

根据Genbank中挪威鼠（Rattus norvegicus）Hspa4基因序列(登录号：NM 153629)和玉米Ubi-1启动子序列(登录号：DQ141598 )设计引物,采用RT-PCR和PCR技术分别进行克隆。测序及同源性分析结果表明：Hspa4基因片段含有2530bp,编码840个氨基酸;获得的启动子Ubi-1序列大小为1992bp;克隆的序列与相应原序列同源性分别为99.96％和99.55%。以植物表达载体pCAMBIA1301质粒为基础,成功构建了植物表达载体pCAMBIA1301-Ubi-Hspa4,为利用Hspa4基因改良植物抗逆性打下了基础。     

大熊猫生长激素基因Am-GH的表达载体构建及其表达研究

植物反应器生产药品成本低,具有改变传统制药方法的光明前景。本研究 以PCR法克隆的大熊猫生长激素基因Am-GH,构建了原核表达载体pEGX-AmGH和植物表达载体pCAMBIA13011-GH。pEGX-AmGH转化E. coli得到高效表达。pCAMBIA13011-GH通过根癌农杆菌GV3101的介导转化烟草无菌叶片外植体,经过四轮潮霉素(Hygromycin, Hyg)递增筛选,获得抗性植株。其中部分Hyg抗性植株经GUS和PCR检测为阳性。鉴定结果表明Am-GH 已成功整合到烟草基因组中。为进一步探讨大熊猫生长激素基因Am-GH在烟草中的表达奠定了基础。     

以木糖异构酶基因作为选择标记的花生遗传转化

用木糖异构酶基因xylA替换掉pCAMBIA1301中的潮霉素磷酸转移酶基因(hygromycin-B-phosphotransferase,Hpt),构建了植物表达载体pCAMBIA1301-xylA。再利用农杆菌介导法将pCAMBIA1301-xylA导入花生,转移到添加蔗糖(5g/L)和不同浓度木糖(5,10,20,30g/L)的体胚诱导及体胚萌发培养基上培养。对外植体成苗率及转基因阳性率进行统计,结果表明,当木糖浓度为10g/L时,诱导成苗率为15.25%,再生植株生长健壮,且转基因阳性率高达77.27%,最终确定10g/L为最适木糖筛选浓度。该筛选方法利用木糖作为筛选剂,可以避免利用抗生素筛选可能造成的安全隐患,转化效率高,是一种安全、高效的筛选方法。     

番茄EBF2基因的克隆、亚细胞定位与遗传转化

为研究番茄EBF2基因的功能,利用RT-PCR技术从番茄果实cDNA中扩增了全长EBF2基因,将其与绿色荧光蛋白(GFP)构建成融合表达载体,在烟草原生质体中进行瞬时表达。结果表明,该基因定位于细胞核内。将该基因定向克隆到植物表达载体pCambia1301,构建成由组成型启动子CaMV35S启动的植物表达载体pCambia1301-EBF2,通过农杆菌介导方法转化MicroTom番茄。经PCR及GUS组织染色检测,外源基因已整合到番茄基因组中。     

水稻钙依赖型蛋白激酶0sCPK9基因RNAi表达载体的构建及遗传转化

水稻钙依赖型蛋白激酶（CDPKs）是一个响应逆境胁迫并在植物发育过程中起重要作用的蛋白激酶。我们采用RT—PCR从水稻品种日本晴（Oryza sativa L．CV．Nipponbare）中克隆了OsCPK9基因靠近翻译起始位点下游的一段280bp的特异基因片段。将该片段以正、反向分别连接到来源于小麦TAK14基因的548bp内含子片段（NCBIaccessionnumber：AF325198）两侧,从而获得pSK．OsCPK9-RNAi的中间表达载体。进而将其克隆到植物双元表达载体pCAMBIA1301中,构建shRNAi表达载体pCAMBIA．05CPK9一RNAi。经酶切和测序鉴定正确后,利用农杆菌介导转化水稻。通过抗性筛选和标记基因hyg和gus进行PCR鉴定,筛选到20株转基因水稻植株,实时荧光定量PCR分析显示,部分转基因植株OsCPK9的表达受到显著抑制。     

植物表达载体pCAMBIA2301-del-ros的构建及其在草莓上的验证

为了研究多基因互作,减少多次转化的不确定性,本研究在花青素合成调节基因del(delila)和ros(rosea1)的上下游分别引入CaMV 35S启动子和nos终止子,以pBI121-del和pCAMBIA1301-ros做中间载体,并利用BamHⅠ和BglⅡ产生相同4碱基末端的片段,在连接酶的作用下将CaMV 35S启动子分别驱动的del和ros基因构建在同一个植物表达载体pCAMBIA2301上,利用所构建的载体pCAMBIA2301-delros通过根癌农杆菌(Agrobacterium tumefaciens)LBA4404介导的方法转化草莓(Fragaria ananassa Duch.),并进行PCR检测,获得转基因草莓。通过组织观察发现,转基因草莓的根和叶的颜色变成红紫色;实时RT-PCR分析表明,在转基因草莓中花青素合成的结构基因花色素合成酶(anthocyanidinsynthase,ANS)、查尔酮异构酶(chalcone-flavanone isomerase,CHI)、查尔酮合酶(chalcone synthase,CHS)、二羟黄酮醇-4-还原酶(dihydroflavonol-4-reductase,DFR)、黄烷酮-3-羟化酶(flavanone 3-hydroxylase,F3H)和类黄酮-3-O-葡糖基转移酶(UDP glucose-flavonoid 3-O-glcosyl-transferase,UFGT)在转基因株系中的表达均上调,这也进一步证实通过该方法构建的植物表达载体pCAMBIA2301-del-ros可以用来转化植物。本研究结果表明,植物表达载体pCAMBIA2301-del-ros成功构建,为多基因植物表达载体的构建提供了一种思路,也为在植物体内同时研究多个基因的互作提供借鉴。     

多选择标记植物表达载体的构建

具有多选择标记的植物基因表达载体有利于转基因植物研究中的转基因植株的筛选。本研究对植物基因表达载体pCAMBIA1301进行了改造,产生了1个具有可溶性的红移绿色荧光蛋白基因（smRS-GFP）、抗除草剂Basta、葡萄糖苷酸酶（GUS）及潮霉素（Hpt）的多选择标记的新的植物基因表达载体。运用这一表达载体的多选择标记可以有效降低检测和筛选转化植株时的假阳性率。此外,如此的基因表达载体也能满足实验室的不同筛选方法的需求。     

香石竹ACC氧化酶基因克隆及其反义表达载体构建

据已报道的香石竹氨基环丙烷羧酸(ACC)氧化酶基因的cDNA序列设计特异引物,以香石竹品种“Master”基因组DNA为模板,用PCR方法克隆出香石竹ACO基因的部分序列。测序结果显示,克隆的序列与已报道序列基本一致。将克隆的香石竹ACO片段反向连接到植物表达载体pCAMBIA 1301中CaMV 35S启动子的下游,构建了香石竹ACO基因的反义表达载体pCAM-ACO2,为进一步通过反义技术延长转基因香石竹的花期奠定了基础。     

Multiple receptors as targets of Cry toxins in mosquitoes

Bacillus thuringiensis (Bt) produces inclusions that are composed of proteins known as crystal proteins or Cry toxins. Due to their high specificity and their safety to humans and the environment, these Cry toxins are considered to be valuable alternatives to chemical pesticides in insect control programs. It is believed that Cry toxin-induced membrane pore formation is responsible for insect toxicity. The molecular mechanism of pore formation involves recognition and subsequent binding of the toxin to membrane receptors. This binding is accompanied by toxin oligomerization and transfer of domain I helices of the toxin to the lipid-water interface. This toxin insertion creates pores that lyse the cells. Several receptors from lepidopteran, coleopteran, and dipteran insects have been well characterized. This paper provides an overview of the understanding of the interactions between Cry toxin and multiple receptors in mosquitoes, in particular Aedes aegypti and reviews the manner by which the receptors were identified and characterized, with a focus on three proteins, cadherin, alkaline phosphatase, and aminopeptidase-N.     

小麦Wcor719基因的原核表达及转化烟草和棉花提高抗冷性研究

为研究Wcor719基因的抗寒功能,获得具有抗寒性的棉花新种质,构建小麦冷诱导基因原核表达载体Wcor719-pET28a进行蛋白表达,SDS-PAGE分析表明其诱导蛋白大小约为24.0kD,表达量在诱导4h时达到最大,且与IPTG诱导浓度无明显相关性。同时通过农杆菌介导的叶盘法将构建的Wcor719-pCambia1301植物表达载体转入烟草(Nicotiana tabacum)SR-1中,T1代转基因烟草植株经过抗生素筛选和PCR检测后进行低温胁迫,测定抗寒生理指标,结果显示转基因植株的脯氨酸和可溶性糖含量均比对照有所提高。该基因经过功能验证后用花粉管通道法转入棉花(Gossypium hirsutum)新陆中49,T0代、T1代经过田间检测及PCR检测后研究T2代转基因棉花低温胁迫下的抗寒性,结果显示,转基因棉花脯氨酸含量和可溶性糖含量均在第5天达到峰值,且明显高于对照;而丙二醛含量低于对照,初步证明转基因烟草和棉花的抗寒性均有所提高,由此表明通过转冷调节基因来提高植物的抗寒性具有良好的应用前景。     

Chemical composition and mosquito larvicidal activity of essential oils from leaves of different Cinnamomum osmophloeum provenances

Chemical compositions of leaf essential oils from eight provenances of indigenous cinnamon (Cinnamomum osmophloeum Kaneh.) were compared. According to GC-MS and cluster analyses, the leaf essential oils of the eight provenances and their relative contents were classified into five chemotypes-cinnamaldehyde type, linalool type, camphor type, cinnamaldehyde/cinnamyl acetate type, and mixed type. The larvicidal activities of leaf essential oils and their constituents from the five chemotypes of indigenous cinnamon trees were evaluated by mosquito larvicidal assay. Results of larvicidal tests demonstrated that the leaf essential oils of cinnamaldehyde type and cinnamaldehyde/cinnamyl acetate type had an excellent inhibitory effect against the fourth-instar larvae of Aedes aegypti. The LC(50) values for cinnamaldehyde type and cinnamaldehyde/cinnamyl acetate type against A. aegypti larvae in 24 h were 36 ppm (LC(90) = 79 ppm) and 44 ppm (LC(90) = 85 ppm), respectively. Results of the 24-h mosquito larvicidal assays also showed that the effective constituents in leaf essential oils were cinnamaldehyde, eugenol, anethole, and cinnamyl acetate and that the LC(50) values of these constituents against A. aegypti larvae were <50 ppm. Cinnamaldehyde had the best mosquito larvicidal activity, with an LC(50) of 29 ppm (LC(90) = 48 ppm) against A. aegypti. Comparisons of mosquito larvicidal activity of cinnamaldehyde congeners revealed that cinnamaldehyde exhibited the strongest mosquito larvicidal activity.     

Emodin isolated from Cassia obtusifolia (Leguminosae) seed shows larvicidal activity against three mosquito species

Mosquito larvicidal activity of Cassia obtusifolia (Leguminosae) seed-derived materials against the fourth-instar larvae of Aedes aegypti, Aedes togoi, and Culex pipiens pallens was examined. The chloroform fraction of C. obtusifolia extract showed a strong larvicidal activity of 100% mortality at 25 mg/L. The biologically active component of C. obtusifolia seeds was characterized as emodin by spectroscopic analyses. The LC(50) values of emodin were 1.4, 1.9, and 2.2 mg/L against C. pipiens pallens, A. aegypti, and A. togoi, respectively. Pirimiphos-methyl acts as a positive control directly compared to emodin. Pirimiphos-methyl was a much more potent mosquito larvicide than emodin. Nonetheless, emodin may be useful as a lead compound and new agent for a naturally occurring mosquito larvicidal agent. In tests with hydroxyanthraquinones, no activity was observed with alizarin, danthron, and quinizarin, but purpurin has an apparent LC(50) value of approximately 19.6 mg/L against A. aegypti.     

Larvicidal activity of lignans identified in Phryma leptostachya Var. asiatica roots against three mosquito species

The insecticidal activity of phytochemicals isolated from the roots of Phryma leptostachya var. asiatica against third instar larvae of Culex pipiens pallens, Aedes aegypti, and Ocheratatos togoi was examined. The two constituents of P. leptostachya var. asiatica roots were identified as the leptostachyol acetate (I) and 8'-acetoxy-2,2',6-trimethoxy-3,4,4',5'-dimethylenedioxyphenyl-7,7'-dioxabicyclo[3.3.0]octane (II) by spectroscopic analysis. Compound I was lethal to C. pipiens pallens, A. aegypti, and O. togoi at 10 ppm. Compound II showed weak or no insecticidal activity against three mosquito species at 10 ppm. The LC(50) values of I against C. pipiens pallens, A. aegypti, and O. togoi were 0.41, 2.1, and 2.3 ppm, respectively. Naturally occurring P. leptostachya var. asiatica root-derived compounds merit further study as potential mosquito larval control agents or lead compounds.     

苏云金芽孢杆菌高效杀蚊菌株BRC-ZLL13的鉴定

苏云金芽孢杆菌BRC-ZLL13是一株从白玉兰叶片中分离的高效杀蚊菌株。它对埃及伊蚊、白纹伊蚊和致倦库蚊的毒力均高于国际标准菌株以色列亚种IPS82,其生长速度也明显快于后者。本实验对该菌株毒力、血清型、生理生化反应、药敏实验、质粒、杀蚊基因和晶体蛋白等方面的生物学特性进行了研究。结果显示,BRC-ZLL13与对照菌株IPS82同属于以色列亚种,均含有cyt1、cyt2、cry4A、cry4B、cry10和cry11等杀蚊基因,二者在生理生化反应、药敏实验和晶体蛋白图谱等生物学特性上也表现出极高的相似性。另一方面,前者比后者少2条质粒带,这可能是导致BRC-ZLL13生长速度较快的主要原因。综上所述,笔者认为该菌株在公共卫生和生物防治领域具有开发和应用潜力。     

Isolation and identification of mosquito bite deterrent terpenoids from leaves of American (Callicarpa americana) and Japanese (Callicarpa japonica) beautyberry

Essential oil extracts from Callicarpa americana and Callicarpa japonica were investigated. Bioassay-guided fractionation of C. americana extracts using the yellow fever mosquito, Aedes aegypti, led to the isolation of alpha-humulene, humulene epoxide II, and intermedeol and a newly isolated terpenoid (callicarpenal). Similar work involving C. japonica resulted in the isolation of an additional compound, spathulenol, as well as the four compounds isolated from C. americana. Structure elucidation was performed on all isolated compounds using a combination of gas chromatography-mass spectrometry-electron ionization, high-resolution liquid chromatography-MS-electrospray ionization, and one- and two-dimensional NMR experiments. Heretofore, 13,14,15,16-tetranorclerodane, callicarpenal, has never been identified from natural sources. Complete (1)H and (13)C NMR assignment data are provided for this compound. In bite deterrent studies, spathulenol, intermedeol, and callicarpenal showed significant repellent activity against A. aegypti and Anopheles stephensi.     

由根癌农杆菌介导将葡萄糖氧化酶基因转入水稻

摘要:将具有广谱抗病作用的葡萄糖氧化酶（glucose oxidase , GO）基因插入具有潮霉素抗性选择标记的双元载体pCAMBIA1301，新构建了水稻高效表达载体pCAG1301。将此质粒导入根癌农杆菌（Agrobacterium tumefaciens ）菌株LBA4404后,转化粳稻(Oryza. sativa L.ssp.japonica )品种日本晴(Nipponbare)的幼胚，并由筛选出的潮霉素抗性愈伤组织分化再生植株。对所得潮霉素抗性水稻植株的Southern杂交分析表明，GO基因已整合到受体基因组。淀粉-碘化钾显色反应检测到了转基因植株产生的过氧化氢，证实GO基因表达产生的葡萄糖氧化酶已经在水稻中发挥功能。抗病性鉴定表明，所得转基因水稻对稻瘟菌(Magnaporthe grisea )具有良好的抗性。     

Furan-2,5-dimethylene-tethered bis-imidacloprid insecticide conferring high potency

Bis-imidacloprid (bis-IMI) analogues with suitable alkylene spacers have plant-systemic insecticidal properties. The alkylene-tethered bis-IMI binds in a unique mode to the insect nicotinic acetylcholine receptor (nAChR) wherein the chloropyridine moieties are embraced by two distinct and distant domains. The heptamethylene spacer optimally bridges these two subsites, yet the linker itself binds in a relatively nonspecific manner. This investigation examines the hypothesis that a bis-IMI analogue with a heteroaromatic tether, which undergoes specific interaction(s) with the newly recognized receptor cavity, may enhance the potency relative to those of the alkylene-tethered derivatives. Remarkably, a novel bis-IMI with a furan-2,5-dimethylene fulcrum showed highest receptor potency and insecticidal activity among the analogues with various chemotype spacers. The nAChR structural model, simulating the binding site interactions of the furan-2,5-dimethylene-tethered bis-IMI, reveals that the furan ring is nestled in a hydrophobic pocket, consisting of three aromatic amino acids, and is stabilized via hydrogen bonding.