马立克氏病病毒pp38基因启动子和增强子的克隆和序列分析

参考GeneBank发表的马立克氏病病毒(MDV)国际标准强毒株GA的基因序列，设计合成一对引物，分别以RBIB，814，GD2(广东分离株)，J-1-E(北京分离株)，Md11，Md5，CV1988等不同毒株的MDV基因组DNA为模板，通过PCR扩增，获得了预期大小的PCR产物。该产物经pGEM-T-easy克隆后测序，将所得序列进行比较分析。结果发现：不同毒株间pp38基因的启动子和增强子序列间有缺失突变，序列的同源性大于95．9％，其中大多数的突变发生在MDV复制的原点附近。     

数字图书馆中的一种容灾系统的设计与实现

随着网络技术的发展，数字图书馆起着越来越重要的作用，但其容灾措施未引起重视。文章首先描述了容灾的概念和原理，然后设计了一种基于复制技术的容灾系统，给出了详细的算法。该容灾系统通过增加服务器的远程备份节点以增强系统的可用性。     

猪瘟病毒在宿主细胞中增殖与遗传变异的研究进展

就瘟病毒属尤其是猪瘟病毒在宿主细胞中的增殖过程及遗传变异两个方面进行了介绍,其中增殖过程主要包括病毒吸附宿主细胞及其内化、基因复制表达、病毒粒子的装配及释放几个步骤,以期为研究瘟病毒在体内的增殖分布规律提供参考。     

新城疫病毒在鸡胚不同组织增殖的研究

不同新城疫病毒Ｆ４８Ｅ８、Ｎ－７９、ＬａＳｏｔａ和分离株Ｘ以１∶１００００稀释接种９日龄ＳＰＦ鸡胚,每胚０．２ｍｌ,结果发现,Ｆ４８Ｅ８和分离株Ｘ毒力较强,可在５０小时左右致死鸡胚,ＬａＳｏｔａ和Ｎ－７９较弱。Ｆ４８Ｅ８和Ｘ株接种鸡胚的肌肉、肝脏、脑和尿囊液均有大量病毒存在,而Ｎ－７９和ＬａＳｏｔａ只在尿囊液中有大量病毒存在,胚体病毒极少。     

PRRSV强、弱毒株Nsp9基因对PRRSV复制的影响

为了探索猪繁殖与呼吸综合征病毒(PRRSV)强、弱毒株的Nsp9基因对PRRSV复制的影响,构建含有PRRSV XH-GD强毒株、CH-1R弱毒株Nsp9全长基因的质粒p IRes2-EGFP-Nsp9-XH-GD、p IRes2-EGFP-Nsp9-CH-1R,并将重组质粒分别转染到Marc-145细胞中,以MOI=1的剂量接种PRRSV XH-GD毒株,通过TCID50试验测定病毒的滴度,采用荧光定量PCR和Western Blot方法来测定病毒的N蛋白表达情况。结果表明,转染弱毒株CH-1R Nsp9基因的Marc-145细胞中,PRRSV的N蛋白在mRNA水平、蛋白质水平上的表达量均高于转染强毒株XH-GD组,且病毒的滴度也显著高于转染强毒株XH-GD组。综上,在Marc-145细胞中,弱毒株CH-1R Nsp9基因对PRRSV复制的促进作用优于强毒株XH-GD。     

Comparative analysis of receptor-binding specificity and pathogenicity in natural reassortant and non-reassortant H3N2 swine influenza virus

Genetic reassortment between human and avian influenza viruses can create pandemic viruses. Influenza surveillance of pigs in Jilin Province, in China during 2007–2008 revealed that there were two distinguishable genotypes: a human-like H3N2 genotype and a double-reassortant genotype derived from the human H3N2 and avian H5 viruses. In this study, viral infection potential, replication kinetics, and pathogenicity were compared. The solid-phase binding assay demonstrated that both viruses prominently maintained a preference for the human-type receptor and the reassortant A/swine/Jilin/37/2008 (Sw/JL/37/08) showed relatively higher binding affinities than the non-reassortant A/swine/Jilin/19/2007 (Sw/JL/19/07). Replication kinetics showed that Sw/JL/37/08 had higher replicability in MDCK cells than Sw/JL/19/07. The mouse experiments clearly revealed that Sw/JL/37/08 had higher virulence than Sw/JL/19/07 as measured by more significant body weight loss, higher viral lung load, delayed viral clearance from lungs, and more severe pulmonary lesions. Sequence analysis indicated that the absence of glycosylation sites at residue 126 of HA and 93 of NA, as well as the characteristic NS1 C-terminal PL residues of ESEV may account for the increased replication and pathogenicity of Sw/JL/37/08. These results may imply that human may have infection risk by the reassortant swine influenza virus and emphasize the necessity for enhanced viral surveillance strategies, which monitor reassortment events in nature to reduce the public health threat posed by influenza viruses with the potential for human-to-human transmission currently circulating in pig populations.     

Ultrastructural Studies of Orf Virus Infection and Replication in Fetal Lamb Fibrocytes

Résumé— Le cycle de réplication du virus de l'ecthyma contagieux a été identifié dans des études in vitro et un modèle hypothétique a été développé. Pendant la premiére phase, qui dure à peu près 5 heures, le virus pénètre la cellule par le biais d'un processus de phagocytose, et perd ses enveloppes. La phase d'éclipse, pendant laquelle le virus est apparemment intégréà l'ADN de l'hôte, dure environ 8 à 10 heures. Pendant la phase finale, les virions se développent dans des zones biens définies du viroplasme à partir desquelles les viriojns matures vont migrer jusqu'aux bords de la cellule. Là, ils sortent soit par exocytose, soit à l'intérieur de projections microvilleuses qui sont pincées à leur base, soit encore par désintégration de la cellule hôte. [Onwuka, S.K., Jenkinson, D. Mc, Inglis, L., Pow, I., GRAY, E.W., Reid, H.W. Ultrastructural studies of orf virus infection and replication in fetal lamb fibrocytes (Etudes ultrasturcturales de l'infection par le virus de l'ecthyma contagieux et de sa réplication dans les fibrocytes de foetus d'agneau). Resumen— Se identificó el ciclo de replicación del virus del ectima contagioso en estudios temporales in vitro y se desarroló un posible modelo experimental. Durante la primera fase, que dura unas 5 h, el virus penetra en la células por fagocitosis y se libera de la cubierta. La fase de “eclipse”, con el virus presentándose como hebras de DNA, dura aproximadamente de 8 a 10 h. En la fase final los viriones se desarrollan dentro de zonas bien definidas en el viroplasma desde las cuales los viriones maduros migran hasta los limites celulares. A partir de alii parecen salir por exocitosis o en proyecciones de microvellosidades “pinzadas” hacia el exterior; también pueden ser liberados como consecuencia de la desintegración de la célula huésped. [Onwuka, S.K., Jenkinson, D. Mc, Inglis, L., Pow, I., GRAY, E.W., Reid, H.W. Ultrastructural studies of orf virus infection and replication in fetal lamb fibrocytes (Estudios ultraestructurales de la infección por el virus del ectima contagioso y replicación en fibrocitos fetales de carnero). Abstract— The cycle of replication of orf virus was identified in temporal in vitro studies and a putative model was developed. During the first phase, which lasts about 5 h, the virus enters the cells by a phagocytic process and uncoats. The “eclipse” phase, with the virus apparently present as strands of DNA, lasts for approximately the next 8–10 h. In the final phase virions develop within well-defined zones of viroplasm from which mature virions migrate to the margins of the cell. There they apparently exit either by exocytosis or within microvillous projections which are “pinched off”; they can also be released by disintegration of the host cell.     

甲型流感病毒NS1蛋白研究进展

甲型流感病毒(Influenza A virus,IAV)是引起每年季节性流感及偶尔的流感大流行的主要病原体,严重危害公共卫生和社会经济。IAV属于分节段的单股负链RNA病毒,其基因组编码多种不同的蛋白质,其中非结构蛋白1(non-structural protein 1,NS1)是IAV的调节宿主免疫应答和病毒致病性的重要毒力因子。NS1具有多种功能,它可以与多种宿主RNA及细胞因子相互作用,在增强病毒mRNA翻译、抑制I型干扰素和细胞凋亡等方面发挥重要作用,因此,深入研究IAV NS1在宿主细胞中的作用,对于更好地理解病毒感染和复制的机制是至关重要的。论文主要根据NS1的免疫逃逸机制、促进病毒复制和适应性进化,以及NS1作为新型治疗靶点在抗流感药物及疫苗的研发上的作用,进行系统分析和综述。