da Silveira Eni Braga, Cordeiro Bruno Arrivabene, Ribeiro Bergmann Morais, de Castro Maria Elita Batista, Soares Elisa Filgueiras, Báo Sônia Nair
Departamento de Biologia Celular, Instituto de Ciências Biológicas, Universidade Estadual de Campinas, C.P. 6109, Campinas 13083-863, SP, Brazil.
Virus Res. 2007 Dec;130(1-2):182-92. doi: 10.1016/j.virusres.2007.06.010. Epub 2007 Jul 23.
An Anticarsia gemmatalis multiple nucleopolyhedrovirus (AgMNPV) mutant, vApAg, induces apoptosis in a cell culture derived from Anticarsia gemmatalis (UFL-AG-286), reducing viral progeny. We have investigated apoptosis induction in vivo by vApAg in A. gemmatalis larvae and its correlation to infectivity reduction. LC(50), LD(50), LT(50) and the mean time to death of larvae were determined for vApAg and AgMNPV. Apoptosis was accessed for hemocytes of infected larvae using light and transmission electron microscopy. All types of hemocytes can be infected by vApAg. After 12h post-infection (h p.i.), typical cellular modifications associated to nucleopolyhedrovirus infection were observed. Apoptosis becomes evident after 24h p.i., and massive after 72h p.i. Necrosis of infected cells was also observed. Despite cell death, hemocytes produced budded viruses and polyhedra. Pl and gh1-type hemocytes presented phagocytic activity. Agarose gel electrophoresis revealed fragmentation of hemocytes DNA at late times post-infection. The LC(50) and LD(50) were between five- and six-fold higher for vApAg. The LT(50) and the mean time to death were higher for vApAg in a same treatment or for a similar mortality induced by AgMNPV. These results show correlation of apoptosis and the reduced infectivity of vApAg in A. gemmatalis larvae.
一种夜蛾多核多角体病毒（AgMNPV）突变体vApAg，可在源自夜蛾（UFL-AG-286）的细胞培养物中诱导细胞凋亡，从而减少病毒后代。我们研究了vApAg在夜蛾幼虫体内诱导的细胞凋亡及其与感染性降低的相关性。测定了vApAg和AgMNPV的半数致死浓度（LC50）、半数致死剂量（LD50）、半数致死时间（LT50）以及幼虫的平均死亡时间。使用光学显微镜和透射电子显微镜观察感染幼虫血细胞的凋亡情况。所有类型的血细胞均可被vApAg感染。感染后12小时（h p.i.），观察到与多核多角体病毒感染相关的典型细胞变化。感染后24小时细胞凋亡变得明显，72小时后大量出现。还观察到感染细胞的坏死。尽管细胞死亡，但血细胞仍产生出芽病毒和多角体。Pl和gh1型血细胞具有吞噬活性。琼脂糖凝胶电泳显示感染后期血细胞DNA发生片段化。vApAg的LC50和LD50高出五到六倍。在相同处理或由AgMNPV诱导的类似死亡率情况下，vApAg的LT50和平均死亡时间更高。这些结果表明细胞凋亡与vApAg在夜蛾幼虫中感染性降低之间存在相关性。
