小RNA病毒与细胞凋亡

在小RNA病毒科中,口蹄疫病毒等不同病毒的不同基因可诱导宿主细胞发生凋亡,其作用机制也不完全相同.论文对小RNA病毒诱导细胞凋亡的机制进行了综述,并对相关研究进行了展望.     

细胞自噬与小RNA病毒相互作用分子机制研究进展

细胞自噬是真核生物中普遍存在的、对细胞内物质进行循环更新,维持内环境稳态的一种自我保护机制。近年研究表明,细胞自噬能够参与小RNA病毒的感染过程,小RNA病毒感染细胞时,快速激活自噬途径,自噬可以通过递呈病毒抗原发挥抗病毒天然免疫功能;同时自噬体为部分小RNA病毒提供复制相关蛋白质和非细胞裂解性释放途径,促进病毒的复制。论文对近年来小RNA病毒感染和细胞自噬相互作用的研究进展进行综述,为进一步阐明小RNA病毒参与自噬调节的作用机制提供参考。     

应用流式细胞术研究犬瘟热病毒感染细胞的凋亡

用犬瘟热病毒 ( CDV) 2种不同毒株感染非洲绿猴肾细胞 ( Vero) ,用流式细胞术分析了病毒诱导的感染细胞的凋亡。结果发现 ,2种毒株感染引起的细胞病变类型不同 ,分为圆缩型与合胞体型 ;2种毒株均可诱导感染细胞凋亡 ,但毒株间的凋亡细胞比例存在差异 ,即产生合胞体型细胞病变的毒株凋亡出现较晚 ,凋亡细胞比例显著低于产生圆缩型细胞病变的毒株 ( P<0 .0 1 )。结果提示 ,不同毒株导致细胞死亡的机制可能不同     

应用流式细胞术研究瘟热病毒感染细胞的凋亡

用犬瘟热病毒（ＣＤＶ）２种不同毒株感染非洲绿猴肾细胞（Ｖｅｒｏ）,用流式细胞术分析了病毒诱导的感染细胞的凋亡。结果发现,２种毒株感染引起的细胞病变类型不同,分为圆缩型与合胞体型;２种毒株均可诱导感染细胞凋亡,但毒株间的凋亡细胞化例存在差异,即产生合胞体型细胞病变的毒株凋亡出现较晚,凋亡细胞比例显著低于产生圆缩型细胞为的毒株（Ｐ〈０．０１）。结果提示,不同毒株导致细胞死亡的机制可能不同。     

山羊痘病毒诱导BHK-21细胞凋亡的检测

为验证山羊痘病毒诱导BHK-21细胞出现凋亡现象的存在,分别采用HE染色、凋亡试剂盒检测、流式细胞仪检测和DNA Ladder检测,对山羊痘病毒感染的BHK[21细胞培养物进行细胞凋亡检测.不同方法检测结果均显示,山羊痘病毒感染BHK-21细胞组相同时间细胞凋亡数明显高于对照组.表明山羊痘病毒可诱导BHK-21细胞发生...     

小RNA病毒基因表达调控研究进展

小RNA病毒科属于正链RNA病毒,该科各属病毒基因组结构和基因表达机制具有保守性。文章对小RNA病毒科病毒基因表达调控,包括非依赖帽状结构的翻译起始、宿主细胞翻译的关闭、病毒多聚蛋白的加工处理和RNA的复制研究进行综述,为阐明该科病毒的致病机理和研究真核生物的基因表达调控提供可借鉴的资料。     

鸡传染性贫血病毒诱导细胞凋亡的研究进展

鸡传染性贫血病毒是鸡传染性贫血病的病原体,能引起雏鸡贫血、淋巴组织萎缩、出血及免疫抑制,是导致许多疫苗免疫失败及雏鸡死亡的主要原因之一。该病毒在世界范围内广泛存在,是养鸡业潜在的巨大威胁。近年来的研究表明,鸡传染性贫血病毒主要是通过其编码的凋亡素诱导雏鸡胸腺和骨髓中的造血祖细胞凋亡而致病的,而凋亡素诱导细胞凋亡的能力与其在细胞中的核定位及半胱氨酸蛋白酶(caspase)等因素密切有关。文章就鸡传染性贫血病毒生物学特征、诱导细胞凋亡的现象及机制的研究进行了综述。     

猪流行性腹泻病毒结构与非结构蛋白诱导细胞凋亡的研究

为了弄清猪流行性腹泻病毒(PEDV)感染后诱导细胞凋亡的关键蛋白，采用基因克隆技术构建PEDV相关病毒蛋白的真核表达质粒，转染至HEK-293T细胞，通过流式细胞术检测其细胞凋亡率。结果显示：PEDV非结构蛋白Nsp3和Nsp5以及结构蛋白M的重组质粒转染细胞后显著诱导细胞凋亡，且诱导的细胞凋亡呈现时间和剂量依赖性，提示Nsp3、Nsp5和M蛋白可能是PEDV的关键促凋亡因子。该结果为进一步研究PEDV诱导细胞凋亡的分子机制奠定了基础。     

蚕的细胞凋亡相关基因及其检测技术

家蚕细胞凋亡是家蚕细胞的主动死亡过程,在家蚕细胞的发育和疾病的发生中起重要的作用,同时也是一种抵御病毒感染的天然性保护机制。而病毒也在长期进化过程中获得了适应性调节细胞凋亡的能力,或通过在病毒复制早期表达凋亡抑制产物,以阻止细胞凋亡达到繁殖子代病毒的目的,或通过晚期表达凋亡诱导物诱导细胞凋亡,以快速有效地释放子代病毒。根据细胞凋亡的典型特征,已经发展出ELISA法,流式细胞仪法等分子生物学检测方法,为更深入地了解细胞凋亡的机制打下了坚实的基础。     

LncRNA 053065对高致病性H5N1亚型禽流感病毒复制能力的影响及其机制初步探索

试验旨在基于前期研究筛选到的功能性长链非编码RNA(lncRNA 053065),探讨其对高致病性H5N1亚型禽流感病毒复制能力的影响及其相关机制。首先对lncRNA 053065进行了一系列生物信息学分析,证实其可能调控病毒复制;通过过表达和敲降lncRNA 053065,发现其显著抑制病毒复制;通过流式细胞术检测病毒感染后细胞的凋亡和坏死,发现过表达lncRNA 053065显著抑制细胞凋亡;通过双荧光素酶检测系统检测病毒聚合酶活性,发现lncRNA 053065对病毒聚合酶活性并无显著影响。结果表明,lncRNA 053065可能通过抑制细胞凋亡来抑制H5N1亚型禽流感病毒的复制。研究为揭示高致病性H5N1亚型禽流感病毒潜在致病机制奠定了基础,也为其防治提供了潜在靶点。     

病毒感染细胞过程中caspases介导的病毒蛋白自剪切研究概况

很多宿主细胞在病毒感染下通常会启动caspases通路凋亡途径导致细胞死亡,避免病毒的进一步扩增和传播.但最近的一些研究表明,病毒能利用激活的caspase蛋白酶对自身(非)结构蛋白进行特异性剪切,以利于病毒在细胞内的复制或参与病毒或宿主其他基因的转录调控等过程.作为一个病毒与宿主细胞相互作用关系的新的研究领域,论文对...     

The structure of foot-and-mouth disease virus: implications for its physical and biological properties

The structure of foot-and-mouth disease virus has been solved at a resolution of 2.9 A by X-ray diffraction techniques. The overall structural organisation of the particle is similar to that seen in other picornaviruses but there are several unique features. Many of these help to explain its characteristic physical and biological properties. In particular the canyon or pit found at the surface of other picornaviruses is lacking, which has important implications for cell attachment and the process of infection. Also there are 60 large disordered protrusions at the surface corresponding to the major antigenic site. This disorder is of particular interest in relation to the striking ability of linear synthetic peptides to induce protective immunity against foot-and-mouth disease.     

Viral intestinal infections of animals and man

The extensive use of negative staining techniques and electron microscopy in diagnostic centers has resulted in a dramatic increase in the number of reported viral enteric infections in man and animals in the last 10 yr. Enteric infection due to adenoviruses, astroviruses, coronaviruses, paramyxoviruses, parvoviruses, picornaviruses (caliciviruses), rotaviruses as well as some unidentified viral particles are described. The brief literature review on each of these virus families is supplemented with clinical cases submitted to the Texas Veterinary Medical Diagnostic Laboratory. Comparative aspects of viral infections between different animal species as well as man are discussed wherever possible.     

Virus Diseases of The Respiratory Tract of Cats

Feline rhinotracheitis (FR) virus antigenically similar to the only known antigenic type of FR virus was isolated from nasal and pharyngeal swabs obtained from four cats with respiratory disease. The incidence of FR virus neutralising antibody in 45 cat serums obtained in the environs of Melbourne was approximately 50%. Data is presented that shows that the incidence of neutralising antibody to 2 antigenically distinct feline picornaviruses was 96% and 87% respectively. Complement fixing antibody to the Chlamydia (Psittacosis) group antigen was not found in any of 35 serums tested; it is suggested that the significance of Chlamydia sp as a cause of feline pneumonitis may require reappraisal.     

Interaction of the attenuated recombinant rIHNV-Gvhsv GFP virus with macrophages from rainbow trout (Oncorhynchus mykiss)

One of the most important threats to the salmonid aquaculture industry is infection caused by novirhabdoviruses such as infectious haematopoietic necrosis virus (IHNV) or viral haemorrhagic septicaemia virus (VHSV). Using reverse genetics, an avirulent recombinant rIHNV-Gvhsv GFP strain was generated, which was able to replicate as effectively as wild type IHNV in a fish cell line and in macrophages. Although this recombinant virus induced protective responses against IHNV and VHSV, the response did not involve the production of antibodies or modulate the expression of some antiviral genes. To determine the immune mechanisms underlying the protection conferred by the rIHNV-Gvhsv GFP virus, different immune parameters (NO production, respiratory burst activity and the induction of apoptosis) were assessed in the macrophage population. The results obtained in the present work may indicate that the Nv protein could be important in the modulation of NO and ROS production. rIHNV-Gvhsv GFP did not appear to have a clear effect on nitric oxide production or apoptosis. However, an increased respiratory burst activity (with levels induced by the recombinant virus significantly higher than the levels induced by the wild type virus), suggests a stimulation of the macrophage population, which could be related to the protection against virulent viruses.     

Electron microscopy demonstration of fibrillar structures in the foot-and-mouth disease virus]

Purified FMD virus was heat treated and then examined by electron microscopy with the negative contrast technique. Fibrils of varying length and thickness were present; they were not present after ribonuclease treatment. They were similar to the fibrils described for other picornaviruses. Viral RNA was the essential component of these artificially arranged fibrils, which were composed of threads about 10 A wide, separated from one another by a gap of about 10 A.     

A rapid procedure for the purification of avian encephalomyelitis viruses

A rapid procedure for the purification of egg-grown or field preparations of avian encephalomyelitis virus (AEV) of neural origin is described. Extracts of infected tissues were clarified and then partly purified with trichlorotrifluorethane (Freon TF), and the virus present was concentrated with polyethylene glycol. The concentrates were then re-extracted with Freon, and a portion was labeled with 125iodine. During subsequent purification steps, virus could be readily detected by monitoring for radioactivity, thus eliminating the need to determine the infectivity in individual fractions or to examine for the presence of virions by electron microscopy. Final purification was achieved by cesium-chloride equilibrium or sucrose-velocity-gradient centrifugation. Virus purified in this manner was shown to be free of tissue debris, to be specific for AEV by immune electron microscopy, and to possess structural proteins characteristic of picornaviruses.     

THE ISOLATION OF PICORNAVIRUSES FROM CATS WITH RESPIRATORY DISEASE

One hundred and sixty samples including nasal swabs, conjunctival swabs, lung tissue, swabs of tonsil and an oral swab were taken from 59 cats suffering from respiratory disease. Thirty-nine of the specimens (from 23 cats) contained agents that produced a rapid cytopathic effect in cultures of feline kidney cells. Two of the isolates were studied in detail, and they were found to be resistant to lipid solvents, stable at pH 5 but not at pH 3, able to pass through a 50 mμ filter and not stabilized to inactivation at 50°C in the presence of molar concentrations of MgCl₂. Electron microscopy of negatively stained preparations revealed particles about 45 mμ in diameter that lacked an outer envelope. These properties indicate that the agents are feline picornaviruses.
Antibodies to one of the isolates were present in 14 of 56 cat serums. Four kittens inoculated with picornaviruses developed upper respiratory tract disease, but 3 died with signs of enteritis possibly caused by concurrent infection with pan-leucopenia virus. Picornaviruses were isolated from nasal swabs from 3 of these kittens, and from lung and spleen of the other.     

H3N2 canine influenza virus causes severe morbidity in dogs with induction of genes related to inflammation and apoptosis

Dogs are companion animals that live in close proximity with humans. Canine H3N2 influenza virus has been isolated from pet dogs that showed severe respiratory signs and other clinical symptoms such as fever, reduced body weight, and interstitial pneumonia. The canine H3N2 influenza virus can be highly transmissible among dogs via aerosols. When we analyzed global gene expression in the lungs of infected dogs, the genes associated with the immune response and cell death were greatly elevated. Taken together, our results suggest that canine H3N2 influenza virus can be easily transmitted among dogs, and that severe pneumonia in the infected dogs may be partially due to the elevated expression of genes related to inflammation and apoptosis.