DNA病毒编码的病毒因子和病毒受体

ＤＮＡ病毒编码的病毒因子和病毒受体杨天兵金奇（病毒基因工程国家重点实验室,北京１０００５２）关键词ＤＮＡ病毒病毒因子病毒受体病毒在长期的进化过程中已演绎出一套用于逃避宿主免疫系统攻击,有利于病毒存活与繁殖的微妙策略。近年来国际上提出了病毒因子（ｖｉｒ...     

XJ-160病毒为辛德毕斯病毒新亚型

ＸＪ－１６０病毒是我国首次分离的辛德毕斯病毒,在对其全基因组核苷酸序列测定的基础上,对病毒基因组序列、病毒同源性和病毒系统进化等进行了较为详细的分析,结果表明：ＸＪ－１６０病毒具有典型的甲病毒属德毕斯病毒的序列特征。该病毒ｎｓｐ３蛋白基因中１１处制失及两处插入（４５１７￣５４８５）,涉及９０年核苷酸。核苷酸序列的系统进化分析表明,ＸＪ－１６０病毒属于辛德毕斯病毒欧洲／非洲亚组。病毒全基因组核苷酸序     

昆津病毒复制子——一种新型病毒载体

病毒复制子 (Replicon) 是指来源于病毒基因组的能够自主复制的RNA分子,保留了病毒非结构蛋白基因,而结构蛋白基因缺失或由外源基因替代。昆津病毒 (Kunjun virus) 为黄病毒科黄病毒属成员,其复制子具有表达效率高、细胞毒性低、遗传稳定等特点,在病毒基因组复制调控机制、外源蛋白表达、新型疫苗和基因治疗等领域得到了广泛应用。以下就昆津病毒复制子系统的构建、特性及应用方面的研究进展作一综述。     

琉球病毒、索尔韦齐病毒、苏里斯病毒等三种沙粒病毒实时荧光RT-PCR检测方法研究

建立可检测琉球病毒(Ryukyu virus,RYKV),索尔韦齐病毒(Solwezi virus,SOLV)以及苏里斯病毒(Souris virus,SOUV)等三种沙粒病毒的实时荧光定量RT-PCR检测方法.分析三种病毒流行病学分布特征,从国际公共数据库搜索下载基因组序列,进行比对分析,确定检测靶标,借助primer premier 6.0生物信息学软件,设计引物和探针,建立实时荧光定量RT-PCR检测方法,利用化学合成和体外转录方法制备模拟样本,比较评价三种方法的检测限、特异性、重复性特征.所建实时荧光定量RT-PCR检测方法均可有效扩增检测病毒RNA靶标,检测限分别为40拷贝/μL、7拷贝/μL和15拷贝/μL,检测汉城病毒、汉滩病毒、登革病毒Ⅰ～Ⅳ型分离株、发热伴血小板减少综合病毒及30份健康人血清样本无非特异性扩增,三种病毒相互间以及其他8种出血热相关沙粒病毒RNA间无交叉反应,重复性比较分析显示变异系数均在2％以内.本研究建立的检测RYKV、SOLV和SOUV三种沙粒病毒的实时荧光RT-PCR方法具备用于相关疑似感染者临床样本、宿主动物标本以及进出口物品的筛查检测的潜力,但因未经基于实际病毒感染样本的比较评价,检测结果的解释仍具有一定的局限性.     

病毒装配的分子生物学

病毒的装配是病毒复制和增殖过程中的一个重要步骤,它不是一个简单的静态的结构生物学问题,而是一个综合的动态的过程。它至少包括了下列几个问题：１．病毒的衣壳蛋白亚基是如何互相识别和装配成病毒衣壳的,是什么机制来控制这一过程的？２．病毒的基因组（ＤＮＡ或Ｒ...     

水生甲壳类动物病毒研究动态——Ⅰ.杆形病毒

水生甲壳类动物病毒的研究始于一种地中海螃蟹(Portunus depurator或Liocarcinus d epurator)体内发现的类呼肠孤病毒 [1]}.随后,人们相继在这类动物体内发现多种病毒,其中约17种为杆形病毒.     

植物病毒的卫星病毒和卫星RNA

植物病毒的卫星病毒和卫星ＲＮＡ陈金标（南京农业大学微生物系２１００９５）病毒是一种无细胞结构的生物体,个体极小,约为２０—４００ｕｒｎ。Ｍａｔｔｈｅｗｓ将它定义为：病毒是丁组或多组核酸分子、它通常祛外完蛋白包裹,且只在适合的寄主细胞里复制。在这种细胞...     

中国番茄黄化曲叶病毒——双生病毒的一个新种

用 2 0个单抗对中国番茄黄化曲叶病毒 (TYLCV CHI)和其他双生病毒进行了测定 ,在血清学水平上证实中国番茄黄化曲叶病毒与中国烟草曲叶病毒有较大的亲缘关系 ;同时报道了TYLCV CHI部分共同区、外壳蛋白N端基因和AV1基因的PCR及其克隆和序列分析 ,从分子水平上证实TYLCV CHI与世界各地的其他双生病毒不同 ,是一种新的粉虱传双生病毒     

脊髓灰质炎病毒2A蛋白在重组病毒中的功能研究

应用所构建的不同脊髓灰质炎病毒-痘苗病毒(下简称PV-VV)重组体,探讨脊髓灰质炎病毒(下简称PV)2A蛋白在重组病毒中的作用。所得到的四个以不同PV基因片段插入痘苗病毒(下简称VV)TK区而形成的重组病毒均有PV抗原的表达,并可诱导抗体产生,但此表达水平明显受到2A蛋白的影响。同时,重组病毒对不同细胞的适应性亦有变化。对此,本文进行了初步的探讨。     

反转录病毒载体系统

反转录病毒载体系统曹虎（江苏省东海县教育局２２２３００）反转录病毒是一种ＲＮＡ病毒,由糖蛋白外壳、两条ＲＮＡ链和含有反转录酶的核心蛋白组成。当包着ＲＮＡ链的核心蛋白进入宿主细胞后。反转录酶启动,以病毒ＲＮＡ链为模板,反转录出单链ＤＮＡ,继而生成双链Ｄ...     

Single-chain antibodies against a plant viral RNA-dependent RNA polymerase confer virus resistance

Crop loss due to viral diseases is still a major problem for agriculture today. We present a strategy to achieve virus resistance based on the expression of single-chain Fv fragments (scFvs) against a conserved domain in a plant viral RNA-dependent RNA polymerase (RdRp), a key enzyme in virus replication. The selected scFvs inhibited complementary RNA synthesis of different plant virus RdRps in vitro and virus replication in planta. Moreover, the scFvs also bound to the RdRp of the distantly related hepatitis C virus. T(1) and T(2) progeny of transgenic lines of Nicotiana benthamiana expressing different scFvs either in the cytosol or in the endoplasmic reticulum showed varying degrees of resistance against four plant viruses from different genera, three of which belong to the Tombusviridae family. Virus resistance based on antibodies to RdRps adds another tool to the repertoire for combating plant viruses.     

植物病毒病媒介昆虫的传毒特性和机制研究进展

植物病毒病是农作物的“癌症”, 至今缺少有效的防治方法。目前已知80%的植物病毒病依赖于媒介昆虫传播, 而媒介昆虫对植物病毒的传播是一个昆虫、 病毒、 寄主植物互作的过程, 历经获毒、 持毒和传毒等多个阶段, 昆虫体内一系列病毒受体或蛋白参与了这个过程。昆虫传播病毒的方式有口针携带式、 前肠保留式和体内循环式3类, 它们各自对应的持久性为非持久性、 半持久性和持久性, 不同昆虫获取这3类病毒的获毒时间、 在体内存留位置和传毒时间也各不相同。 这个过程受到媒介昆虫的性别及龄期、 寄主植物、 环境条件、 昆虫体内共生菌等多种因素的影响。与之相关的蛋白主要有病毒衣壳蛋白(CP)、 次要衣壳蛋白（CPm）、 GroEL蛋白、 辅助因子(HC)和下颚口针蛋白等。近年来对植物病毒基因组的研究也取得了很大的进展, 对昆虫传毒机制的研究正受到越来越广泛的关注。本文综述了近年来该领域内的相关研究进展, 包括昆虫传播植物病毒的传毒方式、 影响传毒效率的因素、 传毒机制特别是昆虫体内与病毒传播可能相关的受体等。     

Влнянне характера эаселення ноля капустноii совкоii(Barathra brassicae L.) эффективноеть трихограммы (Trichogramma evanescens Westw.) (Lepidoptera,Noctuidae; Hymenoptera,Trichogrammatidae)

TSWV belongs to the genus Tospovirus which was established in the family Bunyaviridae, a family of animal viruses. Besides TSWV, Impatiens necrotic spot virus (INSV) and ground nut bud necrosis virus (GBNV) were established as different Tospovirus species. Tospoviruses have quasispherical particles of 85 nm diametre which are surrounded by a membrane and contain 3 RNA species and 4 structural proteins. In Tospovirus infected plant cells virions were detected in cavaties of the endoplasmatic reticulum and additionally amorphous electron dense material accumulates in infected cells. Defective forms of TSWV lack the ability to form complete virus particles. TSWV is the only plant pathogenic virus that is transmitted by thrips which transmit the virus with different efficiency. The virus has an extensive plant host range of more than 360 different species. The developing symptoms depend on the Tospovirus species, the virulence of the virus strains and the environmental conditions.

Based on the reaction of TSWV isolates with N‐specific polyclonal antisera, 3 serogroups were established. The most frequently used technique for serologically based diagnosis of Tospoviruses is DAS ELISA with N‐specific or preadsorbed antisera against complete virus. For TSWV epidemiology distinct weeds and cultural host plants play an important role for the survival of virus and vector. Breeding for resistance is the most important preventive measure of control.     

A guide to the contained use of plant virus infectious clones

Plant virus infectious clones are important tools with wide‐ranging applications in different areas of biology and medicine. Their uses in plant pathology include the study of plant–virus interactions, and screening of germplasm as part of prebreeding programmes for virus resistance. They can also be modified to induce transient plant gene silencing (Virus Induced Gene Silencing – VIGS) and as expression vectors for plant or exogenous proteins, with applications in both plant pathology and more generally for the study of plant gene function. Plant viruses are also increasingly being investigated as expression vectors for in planta production of pharmaceutical products, known as molecular farming. However, plant virus infectious clones may pose a risk to the environment due to their ability to reconstitute fully functional, transmissible viruses. These risks arise from both their inherent pathogenicity and the effect of any introduced genetic modifications. Effective containment measures are therefore required. There has been no single comprehensive review of the biosafety considerations for the contained use of genetically modified plant viruses, despite their increasing importance across many biological fields. This review therefore explores the biosafety considerations for working with genetically modified plant viruses in contained environments, with focus on plant growth facilities. It includes regulatory frameworks, risk assessment, assignment of biosafety levels, facility features and working practices. The review is based on international guidance together with information provided by plant virus researchers.     

CRISPR/Cas9系统在培育抗病毒植物新种质中的应用

随着CRISPR/Cas9系统在基因组编辑技术上的开发和完善,CRISPR/Cas9系统在应用于动物病毒感染性疾病防治并取得相当成效的同时,也逐步被应用到对植物病毒基因组进行高效靶向修饰的研究中。CRISPR/Cas9系统对基因组靶向修饰作用不仅实现了对植物DNA病毒基因组序列的编辑,还展示了其有效作用于植物RNA病毒基因组的潜力,同时CRISPR/Cas9系统还能在基因转录和转录后调控水平发挥作用,说明该系统具有通过多种途径调控植物病毒复制的潜能。相对其他植物病毒病防治策略,该系统对病毒基因组的编辑更精准、对基因表达的调控更稳定,对病毒病的抗性也更为广谱。本文将CRISPR/Cas9系统与其他植物病毒病防治策略进行了比较,概述了该系统在培育植物抗病毒病新种质中的优势,分析了其具体应用在该领域中面临的主要问题,讨论了该系统在培育抗病毒植物新种质应用中的发展趋势。     

Plant virus ecology and epidemiology: historical perspectives,recent progress and future prospects

After clarifying the relationship between the closely related concepts of ecology and epidemiology as they are used in plant virology, this article provides a historical perspective on the subject before discussing recent progress and future prospects. Ecology focuses on virus populations interacting with host populations within a variable environment, while epidemiology focuses on the complex association between virus and host plant, and factors that influence spread. The evolution and growth of plant virus ecology and epidemiology since its inception to the present day, and the major milestones in its development, are illustrated by examples from influential historical reviews published in the Annals of Applied Biology over the last 100 years. Original research papers published in the journal are used to illustrate important ecological and epidemiological principles and new developments in both fields. Both areas are multifaceted with many factors influencing host plants, and virus and vector behaviour. The highly diverse scenarios that arise from this process influence the virus population and the spatiotemporal dynamics of virus distribution and spread. The review then describes exciting progress in research in the areas of molecular epidemiology and ecology, and understanding virus–vector interactions. Application of new molecular techniques has greatly accelerated the rate of progress in understanding virus populations and the way changes in these populations influence epidemics. Viruses cause direct and plant‐mediated indirect effects on insect vectors by modifying their life cycles, fitness and behaviour, and one of the most fascinating recent fields of research concerns plant‐mediated indirect virus manipulation of insect vector behaviour that encourages virus spread. Next, the review describes the current state of knowledge about spread of plant viruses at the critical agro‐ecological interface between managed and natural vegetation. There is an urgent need to understand how viruses move in both directions between the two and be able to anticipate these kinds of events. To obtain an understanding of, and ability to foresee, such events will require a major research effort into the future. The review finishes by discussing the implications of climate change and rapid technological innovation for the types of research needed to avoid virus threats to future world food supplies and plant biodiversity. There has been lamentably little focus on research to determine the magnitude of the threat from diseases caused in diverse plant virus pathosystems under different climate change scenarios. Increasing technological innovation offers many opportunities to help ensure this situation is addressed, and provide plant virus ecology and epidemiology with a very exciting future.     

SOME EFFECTS OF HOST-PLANT NUTRITION ON THE MULTIPLICATION OF VIRUSES

The amounts of tobacco mosaic virus present in systemically infected tobacco plants varied greatly with the mineral nutrition of the plants and were related to the effects on plant growth. With plants in soil, supplements of phosphorus produced the greatest increases in plant size, in virus concentration of expressed sap, and in total virus per plant; nitrogen increased plant size only when phosphorus was also added, and only then increased virus concentration and total virus per plant. Combined supplements of phosphorus and nitrogen doubled the virus concentration of sap and increased the total virus per plant by factors up to forty. Potassium slightly reduced the virus concentration of sap, though it usually increased plant size and total virus per plant. From all plants, only about one-third of the virus contained in leaves was present in sap. Virus production seemed to occur at the expense of normal plant proteins, and the ratio of virus to other nitrogenous materials was highest in plants receiving a supplement of phosphorus but not of nitrogen.
The effects of host nutrition on the production of virus in inoculated leaves resembled those in systemically infected leaves, but were more variable.
No evidence was obtained, with plants grown in soil or sand, that host nutrition had any consistent effect on the intrinsic infectivity of tobacco mosaic virus.
The concentration of virus in sap from potato plants systemically infected with two strains of potato virus X was not consistently affected by fertilizers; the chief effect of host nutrition on virus production was indirect by altering plant size.     

The structure of a spherical plant virus (bromegrass mosaic virus) established by neutron diffraction.

The localization of the RNA in a spherical plant virus is established by neutron diffraction. For BMV, this localization is different at low pH than it is at high pH (swollen virus).     

The C terminus of brome mosaic virus coat protein controls viral cell-to-cell and long-distance movement

To investigate the functional domains of the coat protein (CP; 189 amino acids) of Brome mosaic virus, a plant RNA virus, 19 alanine-scanning mutants were constructed and tested for their infectivity in barley and Nicotiana benthamiana. Despite its apparent normal replicative competence and CP production, the C-terminal mutant F184A produced no virions. Furthermore, virion-forming C-terminal mutants P178A and D182A failed to move from cell to cell in both plant species, and mutants D181A and V187A showed host-specific movement. These results indicate that the C-terminal region of CP plays some important roles in virus movement and encapsidation. The specificity of certain mutations for viral movement in two different plant species is evidence for the involvement of host-specific factors.