转基因作物和转基因技术的发展与未来

转基因作物的安全性问题在20世纪末引起全球性的争论,一些人反对转基因植物和转基因技术.本文概述了转基因植物产生的必然性、应用现状、发展趋势、引起争论的主要原因以及必须建立的安全性保障,阐明对转基因作物和技术应采取的科学态度.     

复合性状转基因植物安全性评价的研究进展

随着转基因技术的不断发展,转基因作物实现了产业化。目前,单性状的转基因作物无法满足农业发展的需求,而复合性状转基因作物拓宽了转基因作物的功能,提高了资源的利用率,满足了农民多元化需求,具有广阔的应用前景,是转基因植物发展的新方向。由于转基因技术有一定的风险,因此对转基因作物的安全性监管较为重要,对于复合性状转基因作物,不同国家的安全性评价制度却不尽相同。综述了不同国家对复合性状转基因作物的安全性评价体制,旨为我国复合性状作物提供监管依据。     

转基因作物安全性的解决方法研究进展

随着转基因技术的不断发展,转基因作物的种植面积逐年扩大.转基因技术在解决全球不断增长的粮食需求和保障农业的可持续发展等方面发挥了重要作用.然而,人们对转基因作物和转基因食品的安全性一直存在争议.为了解决这个问题,科学家研究出了多项分子技术来消除转基因带来的潜在威胁,尤其是近几年出现的"外源基因清除技术",有望成为解决该问题的有力工具.综述了几种解决转基因作物安全性问题的方法及其最新进展,并对几种方法进行了优缺点分析.     

转基因作物的生态安全性问题及其对策

随着转基因作物商业化进程的加快,转基因作物的安全性引起了人们越来越多的关注,主要就转基因作物生态安全性问题以及产生的原因进行综述,并提出我国现阶段应采取的对策。     

提高转基因作物生物安全性的分子策略

随着各类转基因作物的问世及其农产品的不断上市,转基因作物的安全性问题已成为公众关心的焦点。综述了提高转基因作物生物安全性的几种分子策略,其中包括选择标记的去除,转基因的组织特异表达和诱导性表达以及转基因逃逸的控制等。     

转基因抗虫作物对捕食性瓢虫的安全性研究进展

转基因抗虫作物的商业化种植带来了显著的经济、生态和社会效益,对转基因抗虫作物的安全性评价也一直是国内外学者研究的热点。对生物非靶标效应的研究是转基因抗虫作物安全性评价的重要组成部分,农田天敌类生物是其中的重点内容之一。瓢虫是农田生态系统重要的捕食性天敌,评价其在转基因抗虫作物田间是否能通过捕食猎物或取食花粉而接触到杀虫蛋白并富集于体内,进而对自身产生一定的非靶标效应,这对捕食性瓢虫的安全性研究具有重要的意义。本文从捕食性天敌瓢虫的生命表参数、行为功能参数、田间群落参数及体内微环境指标等方面综述了转基因抗虫作物对瓢虫的安全性研究进展,并对后期转基因抗虫作物对田间捕食性天敌的研究方向提出了建议,以期为转基因抗虫作物的环境安全性研究提供理论指导和为进一步完善转基因抗虫作物对瓢虫安全性评价的技术体系提供系统的数据资料。     

转基因作物的食用与环境安全性问题及其对策

自转基因技术研发和商业化生产以来,针对转基因作物的食用安全性和环境安全性问题一直是公众争论的焦点。面对全球粮食安全形势的严峻压力,如何使公众对转基因技术及其产品的客观性保持一种科学性的认识,是摆在各国(特别是发展中国家)政府和科学家面前不可忽视的课题。本文从食品和环境两个方面简要介绍了转基因作物的安全性问题,旨在还原转基因技术的科学真实性,并简要提出转基因作物的安全性对策。     

中国转基因作物风险评估技术研究进展

现代生物技术的发展为利用外源基因培育优良作物品种提供了新的途径,目前国内外已培育出多个高抗害虫的转基因作物。但是,人们对转基因作物潜在的风险尚存在疑问,这是目前转基因作物是否能进一步获准商品化生产的一个重要原因。综述了中国转基因作物研究和转基因产品安全性检测技术取得的主要进展,对我国转基因作物的研究前景进行了展望,并对将来的工作提出了几点建议。     

国内外转基因作物产业化的比较

当前,全球转基因作物研发和产业化迅猛发展, 创造了巨大的经济、社会和生态效益。转基因作物产业化发展的快慢, 是关系到我国农业可持续发展和提高农产品国际竞争力的重大问题。就国内外转基因作物的产业化进行了优劣势比较, 并从影响转基因作物产业化的技术瓶颈和安全性监管两方面进行了探讨。     

国内外转基因作物产业化的比较

当前,全球转基因作物研发和产业化迅猛发展, 创造了巨大的经济、社会和生态效益。转基因作物产业化发展的快慢, 是关系到我国农业可持续发展和提高农产品国际竞争力的重大问题。就国内外转基因作物的产业化进行了优劣势比较, 并从影响转基因作物产业化的技术瓶颈和安全性监管两方面进行了探讨。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.