Effective oral infection is set off by interaction of a group of conserved per os infectivity factors(PIFs) with larval midgut columnar epithelial cells. We constructed pseudotyped viruses by substituting pif1, pif2 o...Effective oral infection is set off by interaction of a group of conserved per os infectivity factors(PIFs) with larval midgut columnar epithelial cells. We constructed pseudotyped viruses by substituting pif1, pif2 or pif3 genes of Helicoverpa armigera nucleopolyhedrovirus(Hear NPV) with their homologs from Mamestra bracissae multiple nucleopolyhedrovirus and tested their infectivity to tissue culture cells and to larvae. Transfection and infection assays revealed that all recombinant viruses generated infectious budded virus in both cell culture and in larvae. Electron microscopy showed synthesized occlusion body and occlusion derived virus(ODV) were morphologically indistinguishable from those of the parental virus. By contrast, feeding assays revealed that pseudotyped viruses could not rescue oral infectivity except for pif3 pseudotyped virus that only partially rescued oral infectivity but at a mortality rate much lower than that of the parental Hear NPV. Consistent with the bioassay result, PIF complex was detected in ODVs of pif3 pseudotyped virus only but not in pif1 or pif2 pseudotyped viruses. Our results suggest that PIF complex is essential for oral infectivity, and in the formation of the PIF complex, PIF1, 2 are virus-specific while PIF3 does not appear to be as specific and can function in heterologous environment, albeit to a much more limited extent.展开更多
在DVD视频光盘文件系统的逻辑结构中,视频管理器(VMG:Video Manager)与视频节目集(VTS:Video Title Set)是两个重要的概念。上一篇文章介绍过VMG是DVD盘片上所有视频节目集的信息汇总表,而VTS是某个影片节目的信息汇总表。VMG包括VMGI,V...在DVD视频光盘文件系统的逻辑结构中,视频管理器(VMG:Video Manager)与视频节目集(VTS:Video Title Set)是两个重要的概念。上一篇文章介绍过VMG是DVD盘片上所有视频节目集的信息汇总表,而VTS是某个影片节目的信息汇总表。VMG包括VMGI,VMGM_VOBS和VMGI_BUP;VTS包括VTS,VTSM_VOBS和VTSI_BUP。VMGI与VTSI对应了DVD光盘中的信息文件,即IFO文件。本篇文章将主要介绍信息文件的结构,主要内容及数据。展开更多
基金supported by grants from the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences (grant No.QYZDJ-SSW-SMC021)the National Natural Science Foundation of China (grants No.31621061 and 31130058)+2 种基金the Virology Key Frontier Science Program of State Key Laboratory of Virology (grant No.klv-2016-03)the National Key R&D Program of China (2017YFD0200400)sponsored by CAS-TWAS President’s Fellowship for International PhD Students
文摘Effective oral infection is set off by interaction of a group of conserved per os infectivity factors(PIFs) with larval midgut columnar epithelial cells. We constructed pseudotyped viruses by substituting pif1, pif2 or pif3 genes of Helicoverpa armigera nucleopolyhedrovirus(Hear NPV) with their homologs from Mamestra bracissae multiple nucleopolyhedrovirus and tested their infectivity to tissue culture cells and to larvae. Transfection and infection assays revealed that all recombinant viruses generated infectious budded virus in both cell culture and in larvae. Electron microscopy showed synthesized occlusion body and occlusion derived virus(ODV) were morphologically indistinguishable from those of the parental virus. By contrast, feeding assays revealed that pseudotyped viruses could not rescue oral infectivity except for pif3 pseudotyped virus that only partially rescued oral infectivity but at a mortality rate much lower than that of the parental Hear NPV. Consistent with the bioassay result, PIF complex was detected in ODVs of pif3 pseudotyped virus only but not in pif1 or pif2 pseudotyped viruses. Our results suggest that PIF complex is essential for oral infectivity, and in the formation of the PIF complex, PIF1, 2 are virus-specific while PIF3 does not appear to be as specific and can function in heterologous environment, albeit to a much more limited extent.
文摘在DVD视频光盘文件系统的逻辑结构中,视频管理器(VMG:Video Manager)与视频节目集(VTS:Video Title Set)是两个重要的概念。上一篇文章介绍过VMG是DVD盘片上所有视频节目集的信息汇总表,而VTS是某个影片节目的信息汇总表。VMG包括VMGI,VMGM_VOBS和VMGI_BUP;VTS包括VTS,VTSM_VOBS和VTSI_BUP。VMGI与VTSI对应了DVD光盘中的信息文件,即IFO文件。本篇文章将主要介绍信息文件的结构,主要内容及数据。
