PCR方法制备地高辛标记DNA探针检测中国对虾非包涵体型杆状病毒

A pair of primers created from information of PmNOBⅢ genome DNA Sal I fragment produced a 355bp band by using Penaeus chinensis non occluded baculovirus (PcNOBV),the WSBV isolate from P.hinensis in mainland China,as the DNA template.The specific PCR product was cloned,sequenced and labeled with digoxigenin (DIG)DNA labeling kit(Boehringer Mannheim).The DIG labeled fragment was tested by dot blot hybridization for sensitivity and specificity with purified PcNOBV nucleocapsid,PcNOBV infected shrimp tissues and healthy shrimp tissues.The detection limit of the DNA probe is 6.8pg of purified PcNOBV DNA.No hybridization signals were observed using DNA from healthy shrimp as template.Healthy P.chinensis,artificially infected P.chinensis and pond reared adult P.chinensis were screened for PcNOBV infection by both PCR and the hybridization assay.The results showed a good relationship between PCR and the hybridization assay.These findings demonstrate that the DIG labeled probe can be used as a sensitive,specific and cost effective reagent for detection of PcNOBV.     

中国对虾非包涵体型杆状病毒核衣壳的分离纯化

An effective procedure for isolation and purification of nucleocapsids of Penaeus chinensis non-occluded baculovirus (PcNOBV) which has destroyed the Chinese shrimp industry since 1993 was described. Gill, stomach, gut and cuticle epidermis under exoskeleton were excised from cultured P. chinensis diseased with typical white spot syndrome and homogenized in liquid nitrogen with TNE buffer containing PMSF and β-ME. The homogenized mixture was filtered through a 0.45μm millipore filter membrane to remove cell debris and ultracentrifuged to pellet the remaining material.The pellet was suspended in PMTNE buffer and laid onto a handmade CsCl gradient. An obvious viral band was observed in the middle of the gradient. Large amounts of virus nucleocapsids were visualized under electron microscope consistently corresponding to the milk-colored viral band. The viral envelope was all lost after purification. The nucleocapsid was bacilliform averaging 80±13nm×380±24nm in size. The negatively stained PcNOBV nucleocapsids revealed 13-16 conspicuous stripes located periodically perpendicular to the longitudinal axis of the nucleocapsids. Six to seven capsomers of 9 nm in diameter were visualized on each side of the stripe.     

慢病毒介导的重组TM9SF1蛋白通过诱导自噬和内质网应激抑制293T细胞生长

九次跨膜超家族蛋白成员1（transmembrane 9 superfamily protein member 1,TM9SF1）在进化过程中高度保守,在人体组织和多种细胞系广泛表达。目前,关于该蛋白质的功能研究十分有限和初步。本研究采用慢病毒介导的TM9SF1表达系统,研究了重组TM9SF1蛋白的生化特点及其对细胞生长的调控作用。慢病毒感染的293T全细胞裂解液的蛋白质免疫印迹结果揭示,TM9SF1蛋白具有表观分子质量约为70 kD的单体及寡聚体两种主要形式;在室温及加热37℃时蛋白质相对稳定,随变性温度升高（56 ℃以上）逐渐失去其稳定性。CCK8法显示,与慢病毒空载体感染的293T细胞比较,TM9SF1慢病毒表达载体感染的293T细胞在感染2 d后增殖明显减缓（P<0.001）。Western印迹结果证明,过表达TM9SF1引起LC3Ⅱ表达明显上调,LC3Ⅱ/LC3Ⅰ比例升高,说明TM9SF1可引起293T细胞发生自噬。荧光实时定量PCR结果显示,过表达TM9SF1的293T细胞内质网应激标志分子CHOP、GADD34和XBP1（S）表达水平是对照细胞的3～4倍,提示发生了内质网应激反应。以上结果提示,TM9SF1具有抑制293T细胞生长的功能,该功能可能与其引起的内质网应激和自噬有关。这一结论将进一步加深对TM9SF1在细胞生长调控中的功能的认识。