Multiple Genetic Components in Bromegrass Mosaic Virus

Bromegrass mosaic virus has three types of structurally similar virions all of which are required for infectivity. The virions contain either one RNA molecule of molecular weight 1.09×10⁶ or 0.99×10⁶ or two of molecular weights 0.75×10⁶ and 0.28×10⁶. A mixture of the isolated RNAs is infectious and deletion of any but the smallest greatly reduces infectivity. The third largest RNA component contains the coat protein gene.     

The Molecular Weight and Other Biophysical Properties of Bromegrass Mosaic Virus

Data are presented which show that bromegrass mosaic virus has a particularly low molecular weight and nucleic acid content. A molecular weight of 4.6 × 10⁶ was calculated from the sedimentation coefficient, S°_20,w = 86.2S, the diffusion coefficient, D_20,w = 1.55 × 10^-7 cm²/sec., and an assumed partial specific volume, [UNK] = 0.708 ml/gm. The virus has a ribonucleic acid content of 1.0 × 10⁶ atomic mass units. Electrophoresis experiments showed that the virus is stable in 0.10 ionic strength buffers in the pH range 3-6. Breakdown of the virus was observed outside this pH range. Some characteristics of the breakdown products are described.     

An X-Ray Scattering Investigation of Wild Cucumber Mosaic Virus and a Related Protein

X-ray scattering data are presented on solutions of wild cucumber mosaic virus and the associated “top component” particles which have little or no RNA. The radii of gyration are 112 Å and 135 Å for bottom and top component, respectively. The radial density distribution within each particle is calculated by Fourier inversion of the scattered amplitudes. The virus particle or bottom component has approximately uniform density with an outer radius of about 140 Å. The transform of the top component shows an almost hollow center extending out to 105 Å with a surrounding shell of high density about 35 Å thick. Thus the RNA would appear to occupy the region inside 105 Å and does not overlap appreciably the region occupied by protein. The virus has associated with it approximately 0.38 gm of water per gm of virus, resulting in an average electron density of 1.25 times that of water.     

Properties of Single- and Double-stranded Ribonucleic Acid from Barley Plants Infected with Bromegrass Mosaic Virus

Incorporation of ³²P into nucleic acids in barley plants infected with bromegrass mosaic virus (BMV) was analyzed by chromatography on methylated albumin kieselguhr (MAK) columns. Treatment with actinomycin D reduced the synthesis of ribosomal ribonucleic acid (RNA) to low levels and allowed the detection of the three components of BMV-RNA in vivo. The kinetic study on ³²P incorporation into these BMV-RNA components suggested that a single cleavage occurred in some of the intact RNA shortly after completion of its synthesis, giving rise to the small and medium components. Chromatographic analyses also revealed a double-stranded, ribonuclease-resistant RNA which has been purified by differential extraction, sucrose-density gradient centrifugation, and MAK column chromatography. This RNA sediments at approximately 14S, is alkali-labile, and has a sharp thermal transition with a T_m of 96 C in 0.1 × standard saline citrate buffer, as determined by susceptibility to ribonuclease. The RNA is absent in uninfected barley plants.     

Structural Analysis of A-Protein of Cucumber Green Mottle Mosaic Virus and Tobacco Mosaic Virus by Synchrotron Small-Angle X-Ray Scattering

The size and shape of A-protein of tobacco mosaic virus coat protein (TMVP) and cucumber green mottle mosaic virus coat protein (CGMMVP) were evaluated by means of small-angle X-ray scattering (SAXS) using a synchrotron radiation source, complemeted by electron microscopic observations. The results imply that TMV and CGMMV A-proteins are composed of three and two subunits, respectively, stacked in the shape of an isosceles triangular prism at lower ionic strength. Considering the difference of the A-protein structure at higher and lower ionic strength, the globular core structure was proposed as a subunit which might be modeled as a thin isosceles triangular prism composed of four globular cores joined by rather flexible segments. These cores correspond probably to four helical regions in a subunit, and rearrange their relative positions according to the external conditions. A slight rearrangement of core positions in a subunit may result in the formation of A-proteins of various shapes.     

黄瓜花叶病毒侵染源的研究

试验证明黄瓜花叶病毒(CMV)可经黄瓜种子传播,传毒率为0.20％,传毒部位为种皮和种胚。经ELISA检测和枯斑反应,7种一年生和12种两年或多年生杂草感染CMV,其中刺儿菜、苦菜、还阳参、黄花蒿、伏委陵菜、鼠掌草和本氏蓼是CMV野生寄主新种,苍耳、柱腺独行菜、凤花菜、益母草和酸浆5种杂草作为CMV野生寄主,属国内首次报道。另外,4种观赏植物和2种树木也感染CMV,变该病毒的防治提供了依据。     

引起马蹄莲花叶病的芋花叶病毒

在采自杭州、北京、上海等地的表现花叶和扭曲症状的马蹄莲(Zanledeschia aethiopica)上检测到一种线状病毒。经测定,其平均粒子长度为745nm,病毒粒子最大分布范围为720—750nm。该病毒经免疫电镜观察与芋花叶病毒(DMV)有紧密的血清学关系,且与3个PVY抗血清也有一定的反应。在病叶细胞中观察到紧密聚集。松散聚集和分散的线状病毒粒子和典型的风轮状内含体。作者认为:感染马蹄莲的该种病毒符合芋花叶病毒的特征。本文对该病毒的血清学关系和组织病变情况进行了分析讨论。     

一株辣椒花叶病毒的生化特性研究

本文对辣椒花叶病毒的生化特性进行了研究。病毒蛋白的紫外吸收,最高280毫微米,最低为260毫微米;以SDS-PAGE测定其分子量为17500;病毒蛋白亚基由148个氨基酸组成。从病毒提纯的核酸为线状RNA;紫外吸收最高为260毫微米,最低230毫微米;经聚丙烯酰胺凝胶电泳测定,其分子量为2.0×10~6。根据形态结构、血清学试验、外壳蛋白亚基组成、核酸和蛋白的分子量等综合分析,我们认为这株辣椒花叶病毒是烟草花叶病毒组(TMV)中的一个毒株。     

Nuclear Magnetic Relaxation Study of Tobacco Mosaic Virus Solutions

The molecular order of water in liquid-crystalline 5-28% tobacco mosaic virus (TMV) solutions was studied by proton spin-spin, spin-lattice, and translational self-diffusion coefficient measurements at various concentrations as well as by deuteron D₂O nuclear magnetic resonance (NMR) studies. The results show that the average H₂O molecule spends less than 1% of its time in an ordered state bound to the TMV backbone. The protons on the TMV molecules themselves, on the other hand have a very short spin-spin relaxation time T₂ of about 20 μs, demonstrating the existence of a high degree of liquid-crystalline order.     

由高粱花叶病毒和甘蔗花叶病毒引发的浙江甘蔗花叶病害

从浙江省5个地区采集表现花叶症状的甘蔗病叶,用马铃薯Y病毒科简并引物做PCR扩增及测序鉴定.序列分析表明,5个甘蔗样品均含有高粱花叶病毒(SrMV),其中3个样品中还存在甘蔗花叶病毒(SCMV)的复合侵染.序列比较和系统进化树分析表明,浙江甘蔗样品中的SrMV序列彼此很相似,核苷酸同源性大于93%,与已报道的4个美国分离物在CP区域同源性很高,但是3′非编码区的同源性却仅为70%左右.SCMV欧洲和中国玉米分离物及美国、南非和澳大利亚甘蔗分离物分别形成两个远缘群体,浙江甘蔗分离物群体位于两者之间;群体间CP氨基酸序列同源性均大于80%.甘蔗和玉米上的SCMV差异明显,多为无义突变.     

菜豆黄色花叶病毒(BYMV)—新疆苜蓿分离株的鉴定

从新疆苜蓿黄斑花叶病株上分离到病毒分离物M-4,该分离物能引起多种豆科值物系统花叶,并在藜科植物上产生局部褪绿斑,易经汁液摩擦接种和蚜虫传毒,不经菜豆种子传毒。病毒致死温度60—65℃,体外保毒期4—5天,稀释限点10~(-3)—10~(-4)。病毒粒体线状,长约660—740nm,宽15nm;在感病的寄主叶片细胞中,电镜观察到风轮状、带状和环状内含体。免疫电镜法测定,该分离物与菜豆黄色花叶病毒(BYMV)抗血清有血清反应。经SDS-聚丙烯酰胺凝胶电泳和氨基酸自动分析仪分析分别测得该病毒的衣壳蛋白亚基分子量为16,200道尔顿,氨基酸残基数128个。鉴定结果认为,分离物M-4是BYMV的一个株系。     

An Isolate of Cucumber Mosaic Virus from Fluted Pumpkin in Nigeria

The properties of a virus isolated from fluted pumpkin (Telfairia occidentalis) was investigated. It produced symptoms in some members of the Solanaceae and Leguminosae, and was transmitted nonpersistently by the aphid, Aphis spiraecola. On the basis of these alone, it is distinct from another previously described virus, Telfairia mosaic virus, which neither caused symptoms in members of these families nor was it transmitted by insects. Furthermore, the virus in crude sap or purified preparations reacted with antiserum to cucumber mosaic virus (CMV), but not with antisera to several common viruses in Nigeria. Electron microscopic examination revealed isometric particles of 29 × 1 nm in diameter. These properties confirmed that the virus is an isolate of CMV, and closely resembles the Y-strain in causing systemic mosaic symptoms in Vigna unguiculata. From infectivity and pathogenicity tests, it is concluded that it is the main cause of mosaic disease in fluted pumpkin.     

应用免疫电镜技术快速检测菜豆黄花叶病毒、马铃薯M病毒和燕麦花叶病毒

应用免疫吸附电流技术(ISEM)可有效地检测腐汁液中的菜豆黄花叶病毒(BYMV)、马铃薯M病毒(PVM)和燕麦花叶病毒(OMV)。BYMV,PVM和OMV三种抗血清的适宜工作浓度和对铜网的适宜包被时间均为1000倍和1小时,对同源病毒的适宜捕获时间分别为4℃下2、2和8小时。PVM和OMV的病汁液检测灵敏度均为稀释4000倍,而BYMV病汁液稀释16000倍时还能检测到少量病毒料子。ISEM捕获法和修饰法的结果表明,这三种病毒之间无血清学交叉反应。     

Dielectric spectroscopy of Tobacco Mosaic Virus

The dielectric properties of the Tobacco Mosaic Virus (TMV) have been measured using time domain dielectric spectroscopy (TDDS) in the temperature range from 1 to 40 degrees C. A single dielectric dispersion is observed in the MHz range. The activation energy of the process is found to be in the range 1-2 kcal/mol. The experimental data could not be completely accounted for by current theoretical models, but evidence indicates that the dielectric loss arises from polarisation of charge on and around the virus.     

黄瓜花叶病毒和烟草花叶病毒在双抗转基因线辣椒内的增殖

本试验以转化CMV CP和TMV CP基因的转基因线辣椒纯合系植株作为研究试材 ,比较了单独或混合接种CMV和TMV后 ,转化线辣椒的抗病性表达特点 ,并测定了两种病毒在植株体内的病毒含量。结果表明 :转化线辣椒不仅能抵抗CMV和TMV的单独侵染 ,而且还能抵抗CMV和TMV的复合侵染。转化线辣椒表现为系统症状延迟出现 7 15d ,显症株率和病害严重度级别大幅度降低 ,CMV和TMV在接种叶、新生叶中的病毒含量明显减低。转基因线辣椒原生质体作为研究试材接种CMV ,测定病毒含量结果表明 :CMV病毒的增殖在转基因线辣椒原生质体内受到明显抑制。在CMV接种浓度为 4 0 μg/mL ,感染原生质体 4 8h后 ,CP(- )植株原生质体内CMV是CP( )的 4 .2倍。这一结果揭示了转基因线辣椒具有抑制病毒增殖的抗病性。