Capping of Viral RNA in Cultured Spodoptera frugiperda Cells Infected with Autographa californica Nuclear Polyhedrosis Virus

Viral RNA from fall armyworm (Spodoptera frugiperda) cells infected with Autographa californica nuclear polyhedrosis virus contains cap structures. Most of the cap labeled in vivo with [³H]methionine or ³²P_i cochromatographed on DEAE-cellulose with the −5 charge marker; a minor component appeared at −4 net charge. The former is probably a cap 1 structure (m⁷GpppX^m_pYp), and the latter is probably a cap 0 (m⁷GpppXp). On the basis of relative labeling of the two caps with [³H]adenosine and [³H]guanosine, we concluded that each cap contained at least one adenosine residue in addition to guanosine and, therefore, that cap 0 contained m⁷GpppAp. Cleavage of [³H]methionine-labeled viral RNA with tobacco acid pyrophosphatase released a labeled component that cochromatographed on polyethyleneimine-cellulose with m⁷Gp, confirming the m⁷GpppX linkage in the cap. These results were also seen with host polyadenylated RNA. The caps appeared in nearly equal abundance in viral polyadenylated and non-polyadenylated RNAs. The ratio of ³²P_i incorporated into the cap to that incorporated into mononucleotides suggested average lengths for the polyadenylated and non-polyadenylated RNAs of 1,800 and 1,200 nucleotides, respectively.     

Separation and Structure of Components of Nuclear Polyhedrosis Virus of the Silkworm

Morphology of structural components of nuclear polyhedrosis virus (NPV) particles of the silkworm (Bombyx mori Linné) was studied by electron microscope using negative staining. NPV particles isolated from polyhedra could be separated into five structural components by centrifugation in sucrose density gradients. The lowest band (band I) was found to consist of thick rod-shaped particles (330 by 80 nm) with knobby surfaces and with occasional protrusion at one end. The second band from the bottom (band II) was shown to consist mainly of slender rod-shaped particles (360 by 60 nm), in which internal structures were visible as a dense mass. Regular striations were also seen on the surface of these particles. By treatment with mercaptoethanol, these particles were drastically damaged, and in some cases the internal substances were partially released, producing empty inner membranes of various degrees of disintegration. In bands III and IV, both empty spherical and empty rod-shaped membranes were present. Band III was rich in empty spherical membranes which were shown to be the outer membranes of thick rod-shaped particles. The empty rod-shaped membranes, the inner membranes, were mainly located in band IV and have cross striations on the surface. It is remarkable that the uppermost band (band V) consisted purely of small spherical particles, somewhat heterogeneous in size and shape (around 20 to 25 nm in diameter), indicating the particles to be the degradation product of the virus particles. Similar particles could also be observed within the empty inner membranes.     

Inhibition of Gene Expression by Peptide Nucleic Acids in Cultured Cells

Abstract

We have tested in cultured cells the capacity of antisense and antigene PNAs to inhibit, in a sequence specific manner, the expression of oncogenes in leukaemia and pancreatic carcinoma cells. The results observed appeared promising and suggest that PNA may play in the future an important role in targeting disease-related genes.     

荨麻蛱蝶核型多角体病毒在病虫脂肪体中的形态发生

本文叙述了一种在高山草原地区较低温度下感染荨麻蛱蝶(Vanessa urticae)的核型多角体病毒的形态发生过程。荨麻蛱蝶幼虫经其病毒多角体感染5日后出现明显变化:细胞核膨大,核仁消失,核内出现清晰区及病毒发生基质。在病毒发生基质的周围,核衣壳大量产生。核衣壳是从这些病毒发生基质四周的模样结构碎片上获得套膜,装配成病毒粒子。随后病毒粒子逐渐进入多角体蛋白中,形成了成熟的单粒包埋型的多角体。观察结果表明,在较低温度下生长的荨麻蛱蝶NPV与在常温下生长的其它NPV有着类似的形态发生过程。     

Characterization of Nuclear Polyhedrosis Virus DNAs

The nuclear polyhedrosis virus DNAs characterized and compared in this study consist of the singly-enveloped nucleocapsids (SNPV) of Trichoplusia ni and the bundles of nucleocapsids common to a single envelope (MNPV) from Spodoptera frugiperda and Rachiplusia ou. The SNPV and MNPV DNAs are very similar in hydrodynamic properties and molecular weights. In addition, the NPV DNAs are similar in size to those extracted from the granulosis viruses that infect T. ni and S. frugiperda. As isolated from purified virus or directly from occluded virus, the nuclear polyhedrosis virus DNAs consist of a mixture of about 20 to 30% double-stranded covalently closed molecules and approximately 60% relaxed circles, with less than 10% in linear duplex form. The molecular weights of all nuclear polyhedrosis virus DNAs as compared in this study are slightly smaller than those of T4 bacteriophage DNA and perhaps slightly smaller than those of the granulosis virus DNAs. The best estimates of these molecular weights by neutral sucrose sedimentation for the nuclear polyhedrosis viruses range from 90 to 100 x 10(6) relative to a size of 108 x 10(6) for T4 DNA. The base compositions of the nuclear polyhedrosis viruses that infect T. ni and S. frugiperda are compared with the respective insect host DNAs.     

油桐尺蠖核型多角体病毒感染Bs484细胞的研究

本文报道利用油桐尺蠖核型多角体病毒感染处于不同培养基及不同培养时间的Ｂｓ４８４细胞的部分感染效果和特征。结果表明,细胞培养基的类型和细胞传代后的时间对病毒感染率和多角体产量以及其它感染特征都有比较明显的影响;经过比较,处于Ｇｒａｃｅ培养基组的传你后三天的Ｂｓ４８４细胞是一个理想ＢｓＮＰＶ感染受试系统。同时发现,健康的油桐尺蠖血淋巴具有提高细胞活性及病毒感染效果的作用。     

Double-stranded Ribonucleic Acid from Cytoplasmic Polyhedrosis Virus of the Silkworm

Ribonucleic acid (RNA) was extracted by phenol treatment from cytoplasmic polyhedrosis virus isolated from the midgut of infected silkworms. This RNA appears as threads when precipitated in alcohol. Two components having different sedimentation constants were observed. The molecular weight of the RNA preparation obtained by sedimentation coefficient (weight-averaged) and intrinsic viscosity was about 2 × 10⁶ to 3 × 10⁶. It was one-half to one-third the size of the calculated molecular weight for an entire RNA molecule in a virion. Electron micrographs of this RNA preparation showed two peaks in the distribution of contour length, at 0.4 and 1.3 μm, which would correspond to molecular weights of 10⁶ and 3 × 10⁶, respectively. The extracted RNA seemed to split into segments at a preferential breaking point. This RNA was soluble in concentrated salt solution, differing from single stranded high-molecular-weight RNA. The base composition of this RNA was complementary in the ratios of adenosine to uridine and guanosine to cytosine. It contained 43% guanosine plus cytosine. Based on its filamentous appearance by electron microscopy, typical pattern of optical rotatory dispersion and circular dichroism, sharp transition of the optical properties on heating, great hyperchromicity on degradation, nonreactivity with formaldehyde, and resistance to ribonucleases, it is concluded that this RNA is double-stranded and has regular base pairings of guanosine-cytosine and adenosine-uridine.     

油桐尺蠖核型多角体病毒的空斑测定

在油桐尺蠖卵巢细胞系上对油桐尺蠖核型多角体病毒(BsNPV)进行了空斑测定。用此方法测定了BsNPV的感染力,并将所得的结果与其TCID_(50)进行比较,结果显示这两种方法在测定病毒感染力时敏感性相似。     

杨树毒蛾核型多角体病毒在病虫脂肪体细胞中的形态发生

本文介绍杨毒蛾核型多角体病毒(Leucoma selicis Nuclear Polyhedrosis Virus)在病虫脂肪体细胞中的形态发生,描述了病毒粒子的形成和包被,包含体的沉积过程以及相伴随的细胞病变。     

Synthesis of Polypeptides Encoded by the Double-stranded RNA Genome of Silkworm Cytoplasmic Polyhedrosis Virus in Xenopus Oocytes

A novel antibacterial compound, macrocarpal A, was isolated from the leaves of Eucalyptus macrocarpa, and its structure was determined on the basis of an X-ray crystal structure analysis. Macrocarpal A is composed of a phloroglucinol dialdehyde and diterpene, having a 3-membered ring, a 5-membered ring and a 7-membered ring.     

In Vitro Survey of Autographa californica Nuclear Polyhedrosis Virus Interaction with Nontarget Vertebrate Host Cells

Thirty-five nontarget host cell lines, 23 of human and 12 of nonhuman vertebrate origin, were exposed to Autographa californica nuclear polyhedrosis virus preparations derived from four different sources: polyhedra, hemolymph, cell culture medium, and cultured cells. The virus and cells were incubated together at two different temperatures, 28 or 37°C, for four different lengths of time, 16, 40, 64, or 168 h, and the cells were assayed for the presence of virus by a peroxidase-antiperoxidase detection method. The estimated sensitivity of the assay as routinely conducted was 0.98 ng of alkali-liberated viral protein and 1.95 ng of budded viral protein per mm². No evidence of frank replication was obtained in any of the 35 cell lines tested, although virus uptake appeared to be quite common. Virus uptake was confirmed in some cases by electron microscopy. The degree of virus uptake appeared to be dependent on cell type, time and temperature of incubation, and viral phenotype. Virus purified from polyhedra was generally taken up more readily than were the other forms tested.     

川尾尺蠖核型多角体病毒的分离鉴定

川尾尺蠖 (ＯｕｒａｐｔｅｒｙｘｅｂｕｌｅａｔＭｏｏｒｅ) ,属鳞翅目 ,尺蛾科。又名寸寸虫 ,拱拱虫。川尾尺蠖食性杂 ,最近发现在贵州危害茶树。川尾尺蠖一年发生两代 ,以老龄幼虫在枝条或叶片上越冬 ,越冬代成虫在湄潭地区于 5月上旬出现 ,第二代成虫于 9月上旬至 1 0月下旬陆续羽化产卵 ,9月下旬至 1 1月上旬孵化进入越冬。 1 995年 8月于贵州湄潭茶园获得自然死亡的川尾尺蠖幼虫 ,经分离鉴定是一株核型多角体病毒。1　材料与方法1.1　多角体的分离纯化将自然死亡的病死虫体充分捣碎 ,以 50 0ｒ/ｍｉｎ离心 3ｍｉｎ ,除去沉淀 (细胞碎片…     

蜀柏毒蛾核型多角体病毒的分离鉴定

本文报道了新分离的一株核型多角体病毒:蜀柏毒蛾核型多角体病毒(Paroceneria orient Nuclear Polyhedrosis Virus)。其多角体为四边形、五边形、大小在1.06—2.42μm。病毒粒子杆状,大小为385×55nm。室内感染蜀柏毒蛾幼虫其死亡率达9S％具较强的毒力。     

柏毒蛾核型多角体病毒的分离鉴定

柏毒蛾核型多角体病毒的分离鉴定李崇荣,彭辉银,周显明,陈新文,谢天恩（贵州省铜仁地区林科所,铜仁５５４３００）（中国科学院武汉病毒研究所,武汉４３００７１）（贵州省林业科学研究院,贵阳５５００１１）关键词柏毒蛾,核型多角体病毒柏毒蛾（Ｐａｒｏｃｅｎｅ...     

Pathways for Virus Assembly around Nucleic Acids

Understanding the pathways by which viral capsid proteins assemble around their genomes could identify key intermediates as potential drug targets. In this work, we use computer simulations to characterize assembly over a wide range of capsid protein–protein interaction strengths and solution ionic strengths. We find that assembly pathways can be categorized into two classes, in which intermediates are either predominantly ordered or disordered. Our results suggest that estimating the protein–protein and the protein–genome binding affinities may be sufficient to predict which pathway occurs. Furthermore, the calculated phase diagrams suggest that knowledge of the dominant assembly pathway and its relationship to control parameters could identify optimal strategies to thwart or redirect assembly to block infection. Finally, analysis of simulation trajectories suggests that the two classes of assembly pathways can be distinguished in single-molecule fluorescence correlation spectroscopy or bulk time-resolved small-angle X-ray scattering experiments.     

茶毛虫核型多角体病毒的血清学特性

用免疫双扩散、对流免疫电泳、酶联免疫吸附试验(ELISA),固相免疫电镜(SPIEM)等技术,对茶毛虫核型多角体病毒(EpNPV)的抗原特性及与其它10种核型多角体病毒的血清学关系进行分析。结果表明,EpNPV粒子的抗血清只能与EpNPV粒子起反应,不与EpNPV的多角体蛋白及其它10种昆虫核型多角体病毒(NPV)粒子发生交叉反应;EpNPV多角体蛋白抗血清除了和其同源的多角体蛋白起反应外,还能和其它两种NPV的多角体蛋白起反应。以上结果说明了EpNPV的结构蛋白具有较高的抗原特异性,而多角体蛋白则没有种间特异性。同时将固相免疫电镜技术应用到昆虫病毒的血清学检测中,取得了较为理想的结果。     

以核多角体病毒为载体在家蚕中生产外源蛋白

以家蚕核多角体病毒(BmNPV)为载体,在家蚕幼虫或家蚕培养细胞系中表达的外源基因越来越多,其表达的产物已涉及到医用药物、医疗诊断、疫苗生产、生物防治等诸多领域,文章就BmNPV的特性及其基因组构造,多角体蛋白基因的特性,重组BmNPV的构建及其在家蚕幼虫体内和细胞系中的表达,BmNPV-家蚕表达系统的外源蛋白生产效率及其应用等各个方面作了全面、系统的综述.     

山楂粉蝶NPV的形态发生及其宿主细胞器的超微病理变化

应用电子显微技术,对山楂粉蝶核型多角体病毒感染三龄幼虫后,该病毒在体内的形态发生过程及其宿主细胞病理超微结构的变化等进行了观察与分析。结果表明：病毒感染７２～１６８ｈ后,山楂粉蝶幼虫中肠上皮细胞内出现病毒发生基质、核衣壳、套膜、丝状纤维或称前多角体蛋白。病毒粒子、病毒束,以及病毒束嵌入多角体蛋白,装配成完全的病毒多角体。在相应的中肠上皮细胞内,细胞器如线粒体、粗面内质网、核糖体、溶酶体等均发生显著的病理变化。同时还应指出的是内质网呈指纹图谱型,板层体与示髓样小体等膜状结构的病理变化比较特殊。