莴苣1-FFT基因的克隆及其功能分析

利用反转录PCR技术和cDNA末端快速扩增(RACE)技术从莴苣中分离出1-FFT(果聚糖:果聚糖1-果糖基转移酶)候选全长cDNA,序列分析表明该基因的开放阅读框中具有β-果糖苷酶单元(蔗糖结合框)、RDP域和EC域三个活性中心域.Southern杂交分析表明该基因在莴苣基因组中以单拷贝形式存在.利用农杆菌介导的叶盘转化法将该基因转入无1-FFT基因的烟草细胞,获得了转基因植株.体外酶反应证实转基因叶片提取物中具有1-FFT活性,该基因编码1-FFT.     

植物生物反应器在药物蛋白生产中的应用

以植物为生物反应器表达和生产药物蛋白是近十几年来基因工程研究的一大热点．植物药物蛋白的生产具有成本低、安全、有效等优点,但是植物药物蛋白生产中存在表达量低、下游加工处理困难、糖链结构改变等问题,严重限制了植物表达重组药物蛋白的产业化发展．综述了植物生产重组药物蛋白的优缺点,并对潜在的问题及应对策略进行了探讨．     

美国转基因大西洋鲑产业化对我国的启示

2015年11月19日,美国食品药品监督管理局(FDA)批准了转全鱼生长激素基因(gh)大西洋鲑为第一种可供食用的转基因动物产品,从而取得世界转基因动物育种研究与产业化的历史性突破。经过了长达20年的严格审核,转gh大西洋鲑才获准产业化,不仅充分说明了对包括转基因鱼在内的创新产业的管理决策尤其需要尊重科学规律和客观事实;而且表明基础研究只是产业创新的因素之一,转基因知识的科学普及与企业的积极参与是推动高新技术发展和创新产业形成不可或缺的重要条件;高屋建瓴地制定我国基因改良农业品种市场准入的条例和操作细则已经刻不容缓。     

Purification and characterization of recombinant human erythropoietin from milk of transgenic pigs

BACKGROUND: Human erythropoietin (hEPO), a hydrophobic acidic glycoprotein responsible for the regulation of red blood cell production in mammals, is used for the treatment of anemia. In general, the purification of transgenic animal‐derived therapeutic proteins is not easy due to their low titer concentrations and abundant contaminant proteins. For the first time, here the purification and characterization of rhEPO from the milk of transgenic pigs are described. RESULTS: The rhEPO was purified by heparin chromatography, reverse‐phase chromatography, and gel filtration chromatography, resulting in a 16.5% yield and > 98% purity. The rhEPO purified from the milk of transgenic pigs contained less acidic isoforms and was underglycosylated in contrast to CHO‐derived rhEPO. Cell proliferation of the F‐36/EPO‐dependent cell line was proportional to the dose of transgenic pig‐derived rhEPO. CONCLUSION: Transgenic pig‐derived rhEPO with high purity was achieved after three‐step chromatography following two‐step precipitation. The transgenic pig‐derived rhEPO was demonstrated to have comparable potency with CHO‐derived rhEPO. Transgenic pig‐derived rhEPO may not be therapeutically feasible because of different glycosylation, and thus further studies are required to elucidate the effect of this aberrant glycosylation on the biological activity and stability in vivo. Copyright © 2008 Society of Chemical Industry     

Three-Dimensional Visualization of Transgenic Tobacco Leaves

We have done a three-dimensional visualization of transgenic tobacco (Nicotiana tabacum) leaves for the study of chloroplast gene expression and regulation. The aim was to visualize tobacco leaves shot with tungsten particles. These tungsten particles were coated with the foreign DNA and shot into the leaf using the biolistic technique of DNA insertion. The visualization can be used to examine the leaves to gauge the efficiency of the shooting process, i.e.,to see what parts of the leaves have been effectively penetrated by the DNA-coated tungsten particles and also to judge the depth of penetration. The image data for the 3D visualization was collected at planes 10 microns apart, using a prototype version of a High Numerical Aperture Reflecting Microscope. The raw image data collected from the microscope was restored using the Row Action Projection (RAP) algorithm and the Partial Minimization and Constrained Iteration (PCMI) algorithm. These restored images were then used for 3D visualization using the Visualization Toolkit.     

Trehalose Metabolism: From Osmoprotection to Signaling

Trehalose is a non-reducing disaccharide formed by two glucose molecules. It is widely distributed in Nature and has been isolated from certain species of bacteria, fungi, invertebrates and plants, which are capable of surviving in a dehydrated state for months or years and subsequently being revived after a few hours of being in contact with water. This disaccharide has many biotechnological applications, as its physicochemical properties allow it to be used to preserve foods, enzymes, vaccines, cells etc., in a dehydrated state at room temperature. One of the most striking findings a decade ago was the discovery of the genes involved in trehalose biosynthesis, present in a great number of organisms that do not accumulate trehalose to significant levels. In plants, this disaccharide has diverse functions and plays an essential role in various stages of development, for example in the formation of the embryo and in flowering. Trehalose also appears to be involved in the regulation of carbon metabolism and photosynthesis. Recently it has been discovered that this sugar plays an important role in plant-microorganism interactions.