基因工程的发展现状与前景展望

1972年,PaulBerg构建了世界上第一个重组DNA分子,自此,基因工程便诞生了,并很快掀起了基因工程研究的热潮。27年来,基因工程技术已获得了突飞猛进的发展,取得了许多世人瞩目的成就,对农业生产、医疗卫生、轻工食品和环境卫生等诸多方面产生了巨大的影响,正在成为生物学研究的最前沿学科。科学家们预言,以基因工程技术为主体的生物技术将成为21世纪新技术的主导技术之一。     

Biotechnology and sustainable development in sub-Saharan Africa

Whether development is defined by the long-standing economic parameter of per capita gross national product (GNP) or by the newly introduced Human Development Index (HDI), which is not based exclusively on per capita GNP, the countries of sub-Saharan Africa rank at or near the bottom of the developing world. Agriculture and agro-based processing are the mainstays of the economies of the majority of these countries. Because of this, and also because many of the diseases endemic in these countries are communicable, the application of modern biotechnology (including genetic engineering, tissue culture and monoclonal antibody technology) and related biotechnologies could play an important part in creating sustainable development in the region. There is, therefore, an urgent need to train more of the region's indigenous citizens, and to equip more laboratories, in modern biotechnology. It is suggested that, in order to accelerate the harnessing of the fruits of biotechnology, more countries in the region should affiliate with the International Centre for Genetic Engineering and Biotechnology (ICGEB). It is further suggested that a regional equivalent of the ICGEB be built and the services of non-governmental biotechnology organizations used.The author is with Nnamdi Azikiwe University, P. M. B. 5025, Awka, Nigeria. Address correspondence to P. M. B. 1457, Enugu, Nigeria     

生物多样性的几个问题（续）

从生物多样性的现状、存在的问题及应采取的措施等三个方面比较全面地叙述了我国生物多样性的情况。“生物安全”是《生物多样性公约《签订后每次缔约国会议都要讨论的中心议题之一。为之本文也用一定的篇幅作了较详细的介绍。     

生物多样性的几个问题

本文从生物多样性的现状、存在的问题及应采取的措施等三个方面比较全面地叙述了我国生物多样性的情况。“生物安全”是《生物多样性公约》签订后每次缔约国会议都要讨论的中心议题之一。为之,本文也用一定的篇幅作了较详细的介绍。现状部分从物种多样性、遗传多样性及生态系统多样性等三个方面作了介绍,又从自然因素以及由于人类活动造成栖息地的丧失、环境恶化、偷猎走私、过度捕捞和水产养殖、高新技术发展、全球气候变化以及外     

The Fungal Genetics Stock Center in the context of a world wide community of ex situ fungal germplasm repositories

Most fungal biology researchers depend on culture collections, or more aptly, ex situ fungal germplasm repositories, either for the materials upon which they work, or as a long-term home for their materials after their projects are finished. These collections are broadly distributed and typically supported by the local government. The large number of collections, notwithstanding, some collections have greater impact than others. This review will discuss the fungal germplasm repositories around the world with special attention paid to the Fungal Genetics Stock Center. To facilitate their activities collections have joined together in networks, both locally and internationally. Additional information on public policy and how it impacts collections will be presented and the impact of collections will be highlighted.     

Evolutionary Impact of In tracellular Symbiosis

Intracellular symbiosis involving two or more species can influence the rapid development and evolution of both the participating organisms, and the environments where they are found. At the cellular level, such associations direct the evolution of metabolic pathways and organelle systems, providing degrees of flexibility not found in single organisms. At the environmental level, they are a significant biogeochemical force that shapes habitats and ecosystems. As such, they are major elements of production and stability. Specific examples of both the cellular and the environmental impact of intracellular symbiosis are presented. Their significance in the overall evolution of the organic world is discussed.     

猪-人异种器官移植研究现状

异种器官移植有望用于解决临床移植的器官供需失衡问题。猪具有的天然优势使其比非人灵长类动物更适合作为移植器官的供体。而猪器官移植后出现的一系列生物学障碍已被人们通过基因工程和药物抑制等手段克服。同时,基因工程技术的日渐成熟显著优化了异种移植适用猪的构建方案,推动了猪器官移植研究的发展。尽管猪器官异种移植真正进入临床实验阶段尚需时日,但近年来在少数脑死亡或重症患者身上进行的猪器官移植实验已展现出猪器官异种移植在解决临床移植器官供需失衡问题上的巨大应用前景。     

Stable transformation of the cotton plastid genome and maternal inheritance of transgenes

Chloroplast genetic engineering overcomes concerns of gene containment, low levels of transgene expression, gene silencing, positional and pleiotropic effects or presence of vector sequences in transformed genomes. Several therapeutic proteins and agronomic traits have been highly expressed via the tobacco chloroplast genome but extending this concept to important crops has been a major challenge; lack of 100 homologous species-specific chloroplast transformation vectors containing suitable selectable markers, ability to regulate transgene expression in developing plastids and inadequate tissue culture systems via somatic embryogenesis are major challenges. We employed a Double Gene/Single Selection (DGSS) plastid transformation vector that harbors two selectable marker genes (aphA-6 and nptII) to detoxify the same antibiotic by two enzymes, irrespective of the type of tissues or plastids; by combining this with an efficient regeneration system via somatic embryogenesis, cotton plastid transformation was achieved for the first time. The DGSS transformation vector is at least 8-fold (1 event/2.4 bombarded plates) more efficient than Single Gene/Single Selection (SGSS) vector (aphA-6; 1 event per 20 bombarded plates). Chloroplast transgenic lines were fertile, flowered and set seeds similar to untransformed plants. Transgenes stably integrated into the cotton chloroplast genome were maternally inherited and were not transmitted via pollen when out-crossed with untransformed female plants. Cotton is one of the most important genetically modified crops ($ 120 billion US annual economy). Successful transformation of the chloroplast genome should address concerns about transgene escape, insects developing resistance, inadequate insect control and promote public acceptance of genetically modified cotton.     

Defying the activity–stability trade-off in enzymes: taking advantage of entropy to enhance activity and thermostability

The biotechnological applications of enzymes are limited due to the activity–stability trade-off, which implies that an increase in activity is accompanied by a concomitant decrease in protein stability. This premise is based on thermally adapted homologous enzymes where cold-adapted enzymes show high intrinsic activity linked to enhanced thermolability. In contrast, thermophilic enzymes show low activity around ambient temperatures. Nevertheless, genetically and chemically modified enzymes are beginning to show that the activity–stability trade-off can be overcome. In this review, the origin of the activity–stability trade-off, the thermodynamic basis for enhanced activity and stability, and various approaches for escaping the activity–stability trade-off are discussed. The role of entropy in enhancing both the activity and the stability of enzymes is highlighted with a special emphasis placed on the involvement of solvent water molecules. This review is concluded with suggestions for further research, which underscores the implications of these findings in the context of productivity curves, the Daniel–Danson equilibrium model, catalytic antibodies, and life on cold planets.     

植物外源凝集素及其在植物基因工程中的应用

植物外源凝集素及其基因研究近年来发展迅速 ,尤其是在植物基因工程中 ,植物外源凝集素越来越受到重视。本文介绍了植物外源凝集素的分类、分布、多样性、基本组成与结构、凝集素基因同源性、表达及生物学功能等。重点讨论了凝集素基因在植物基因工程中的应用     

植物磷酸烯醇式丙酮酸羧化酶的功能及其在基因工程中的应用

植物磷酸烯醇式丙酮酸羧化酶(Phosphoenolpyruvate carboxylase,PEPC,EC 4.1.1.31)是广泛存在的一种细胞质酶,催化磷酸烯醇式丙酮酸(PEP)和HCO3-生成草酰乙酸(OAA),后者可转化生成三羧酸循环的多种中间产物.PEPC在植物细胞中参与植物的光合碳同化等重要代谢途径,并且在不同组织中具有多种生理功能.PEPC同时也参与调控植物种子的营养物质合成与代谢过程,控制糖类物质流向脂肪酸合成或蛋白质合成途径.以下介绍了植物PEPC的种类、蛋白质结构特点及其在植物组织中的调控方式,并重点论述了PEPC在生物基因工程中的应用方面的进展,随着对其功能机制和应用研究的深入,将有助于植物PEPC在高产优质农作物育种、能源植物和工业微生物等的开发利用等方面得到更好的发展与应用.     

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.     

奇异果甜蛋白及其基因工程

奇异果甜蛋白(thaumatin)是迄今为止最甜的物质之一,对其研究具有很重要的意义。奇异果甜蛋白的生化性质基本清楚,基因序列和氨基酸序列都已测定。它的甜味可能是由奇异果甜蛋白上特定基团和受体结合引起的。对奇异果甜蛋白的生理功能知之甚少。近二十年来,在奇异果甜蛋白的基因工程上取得了一定进展,但仍然存在许多困难。Abstract:Thaumatin is one of the sweetest substances known to date,it is important to study the thaumatin.The biochemical properties of thaumatin have been clarified clearly.Thaumatin had been isolated and sequenced.The mechanism of the sweetness of thaumatin may be due to the combination of some special groups and the receptors.The exact function of thaumatin is still not clear.Although gene engineering of thaumatin has been carried out for 20 years,there are still some difficulties to be solved for using in the market.     

Stable transformation of petunia plastids

Plastid transformation results in stably expressed foreign genes, which for most Angiosperms are largely excluded from sperm cells, thereby greatly reducing the risk of foreign gene spread through pollen. Prior to this work, fertile plastid transformants were restricted to tobacco, tomato and Lesquerella . Application of plastid engineering in the important floriculture industry requires the development of stable plastid transformation in a major ornamental plant species such as Petunia hybrida. Here we describe the successful isolation of fertile and stable plastid transformants in a commercial cultivar of P. hybrida (var. Pink Wave). Plastid targeting regions from tobacco were used to integrate aad A and gusA between the acc D and rbc L genes of P. hybrida plastid DNA following particle bombardment of leaves. For three spectinomycin and streptomycin resistant lines, DNA blot analysis confirmed transgene integration into plastid DNA and homoplasmy. Maternal inheritance and homoplasmy resulted in 100 transmission of spectinomycin resistance to progeny after selfing. Plastid transformants expressed the gusA gene uniformly within leaves and to comparable levels in all three lines. Insertion of trait genes in place of gusA coding sequences enables immediate applications of our plastid transformation vector. Establishment of plastid transformation in P. hybrida facilitates a safe and reliable use of this important ornamental plant for research and plant biotechnology.These two authors contributed equally to this work.