Detection of a non-structural protein of M r 11 000 encoded by the virion DNA of maize streak virus

A polypeptide of approximately 11 000 daltons (11 kDa protein) encoded by an open reading frame (10.9 ORF) from the virion sense of maize streak virus (MSV) DNA has been detected among the products of in vitro translation reactions programmed with RNA from infected maize plants and also in total protein extracts from infected leaves. The 11 kDa protein has not been detected in virions and is therefore proposed to have a nonstructural role.Viral DNA with an additional in-frame translation stop codon in the 10.9 ORF was not infectious when transmitted to maize plants via Agrobacterium tumefaciens agroinfection, suggesting that the 10.9 ORF may be essential for virus function. Computer comparison data show that equivalent ORFs in wheat dwarf virus (WDV) and digitaria streak virus (DSV) have some sequences in common with the 10.9 ORF of MSV. Further-more, the absence of similar sequences in geminiviruses which infect dicotyledonous plants suggests that the 11 kDa protein and its putative homologs in WDV and DSV have a function necessary only for those geminiviruses which infect the Gramineae.The significance of the 11 kDa protein in relation to expression of the virion sense DNA of MSV is discussed.     

A putative replicative form of the abutilon mosaic virus (gemini group) in a chromatin-like structure

Summary The putative replicative form of the abutilon mosaic virus (AbMV), a geminivirus, was purified from infected plants. It was shown to consist of a bipartite genome of 2660 and 2640 bp. This double-stranded DNA has a closed or relaxed circular conformation and part of it is packed in nucleoprotein complexes with a chromatin-like structure. Similarities between the geminiviruses and the animal simian virus 40 are discussed against this back-ground.Cloning was performed under L2/B1 conditions according to the licence of the ZKBS 1526/1This article is based on a doctoral study by A.A. and T.F. in the Faculty of Biology, University of Hamburg     

应用蛋白印迹法检测鼻咽癌病人血清中抗Epstein—Barr病毒IgA/EA抗体

曾毅等建立了一系列检测EB病毒IgA/VCA和IgA/EA抗体的鼻咽癌早期诊断方法,取得了满意的结果。为了进一步提高对鼻咽癌诊断更为特异的IgA/EA抗体的检出率,我们建立了检测EB病毒IgA/EA抗体的蛋白印迹法。方法敏感特异,结果令人满意。 本法中所用的两个质粒系由本实验室与西德Pettenkofer研究所Wolf教授的实验室合作构建。pUCARG1140和pUC9MBcE3.2质粒均为表达质粒,前者携带着来源于EB病毒Bam     

单克隆抗体对肾综合征出血热病毒50k蛋白的分析

用18株抗肾综合征出血热(Hemorrhagic fever with renal syndrome,以下简称HFRS)病毒McAb,以Western-blot技术分析了纯化的该病毒50k蛋白。结果有7株McAb可与该蛋白反应。这7株McAb的特性(包括感染细胞膜抗原免疫荧光染色模式、中和活性及HI活性等)亦各不相同,提示它们所针对的抗原决定簇的特性也不同。用ELISA阻断试验等证明,上述7株McAb中,有5株所针对的抗原决定簇之间有部分相同或重叠,提示这些具有不同特性的抗原决定簇确实位于同一结构蛋白上。分析结果表明,该50k蛋白的特性及结构均较复杂,尚须进一步研究。     

纸坊病病毒病因的研究

1985年4～10月与1986年6～8月,在贵州省沿河县的纸坊村和崔家坨村先后发生了病因不明的传染病。纸坊村约有1/5的村民发病,病死率为12％,崔家坨村有1/10的村民发病,病死率高达30％。发病波及各年龄组,以青壮年为多,有家庭集聚现象。 本病起病急,轻症者只有头晕、乏力、肌痛、多汗、心悸伴以低热,有的初期有短暂的腹泻。重症者有高热(40℃以上)、大汗、心悸、游走性肌肉痉挛伴有明显疼痛和触痛,以腰骶部及四肢肌肉为好发部位。病人烦燥不安,2～5天内死亡。经实验室检查,排除了食物中毒、农药中毒、钩端螺旋体病和弓形体感染。从病人和接触者的粪便中分离到9株病毒,性状一致,为RNA型25nm的球形颗粒,耐酸,耐乙醚,能凝集人“O”型血球。经血清学鉴定为ECHO3型病毒。16份病人双份血清的检测结果表明,恢复期血清对该病毒中和抗体有4倍以上升高者共8例(纸坊村和崔家坨各4例)。病人单份血清也都有较高的抗体。有理由认为两年中先后在两个村庄发生的传染病与ECHO3型病毒有密切关系。查阅文献,尚未见有关ECHO3型病毒引起以肌痛、游走性肌痉挛为特征的疾病的报道。     

用体外免疫法建立人—人抗流行性乙型脑炎病毒杂交瘤细胞株

利用单克隆抗体(McAb)进行病毒病的治疗是人们所关心的一个重大课题。 流行性乙型脑炎(乙脑)是一种严重威胁人民健康的急性传染病,病死率高,后遗症严重。国内外目前尚无特效疗法。陈伯权等用乙脑病毒皮下或腹腔感染3周龄小白鼠24、48小时及5天后,分别用乙脑病毒51-8McAb进行治疗,平均治愈率分别为78％、73％及22％。     

流行性出血热病毒R22株cDNA克隆及其特异性鉴定

用家鼠型流行性出血热病毒R22株RNA,经polyA接尾,以Oligo-dT做引物,合成cDNA。用pUC18为载体转染E.coli Mc1061,建立cDNA克隆。再经菌落杂交,选择病毒特异性的5个阳性克隆制成缺口翻译探针,与病毒RNA3个片段进行反杂交,确定RNA片段的特异性。结果表明,3个克隆为中(M)片段的cDNA,另两个分别为大(L)和小(S)片段cDNA。核苷酸序列分析证明,克隆的DNA中含病毒特异的核苷酸序列。     

Resistance ofSpodoptera frugiperda [Lep.: Noctuidae] to a nuclear polyhedrosis virus in the field and laboratory

Median lethal doses (LD₅₀s) of nuclear polyhedrosis virus (NPV) were determined in neonatal offspring ofSpodoptera frugiperda (J. E. Smith) (Sf) larvae captured in southeastern Louisiana in 1981, 1982, and 1984. These LD₅₀s ranged from 1.8 to 16.3 polyhedral inclusion bodies (PIB)/insect. The LD₅₀s significantly (P<0.05) increased during the season of 1982 but had no pattern in 1981 or 1984. However, the Sf populations increased in heterogeneity of response to the NPV during all 3 years. The LD₅₀ increased from 4.1 to 18.7 PIB/insect in a Sf laboratory colony exposed to the NPV LD₈₀ for 7 generations, whereas in a control colony not exposed to NPV the LD₅₀ was 5.9 PIB/insect after 7 generations.     

Control ofThrips tabaci [Thysanoptera: Thripidae] on glasshouse cucumber using large introductions of predatory mitesAmblyseius barkeri [Acarina: Phytoseiidae]

The phytoseiid miteAmblyseius barkeri (Hughes) (=Amblyseius mckenziei Sch. & Pr.) was used for biological control ofThrips tabaci Lind. in 7 commercial glasshouses with cucumber (a total of 5780 m²). Predatory mites were introduced 3–4 times in densities ranging from 40 to 300/m² at each release. In 6 of the 7 glasshouses, control of thrips was satisfactory throughout the growing season. Thrips densities were kept below 15 individuals per leaf. In 1 glasshouse, thrips damage was seen on the fruits at densities of 25 thrips per leaf, but the thrips population was quickly reduced and remained at low densities for the next 3 months.      

Persistent measles virus infection enhances major histocompatibility complex class I expression and immunogenicity of murine neuroblastoma cells

The effect of persistent measles virus infection on the expression of major histocompatibility complex (MHC) class I antigens was studied. Mouse neuroblastoma cells C1300, clone NS20Y, were persistently infected with the Edmonston strain of measles virus. The persistently infected cell line, NS20Y/MS, expressed augmented levels of both H-2K^k and H-2D^d MHC class I glycoproteins. Activation of two interferon(IFN)-induced enzymes, known to be part of the IFN system: (2–5)oligoadenylate synthetase and double-stranded-RNA-activated protein kinase, was detected. Measles-virus-infected cells elicited cytotoxic T lymphocytes that recognized and lysed virus-infected and uninfected neuroblastoma cells in an H-2-restricted fashion. Furthermore, immunization of mice with persistently infected cells conferred resistance to tumor growth after challenge with the highly malignant NS20Y cells. The rationale for using measles virus for immunotherapy is that most patients develop lifelong immunity after recovery or vaccination from this infection. Patients developing cancer are likely to have memory cells. A secondary response induced by measles-virus-infected cells may therefore induce an efficient immune response against non-infected tumour cells.