Federici B A, Govindarajan R
Department of Entomology, University of California, Riverside 92521.
J Invertebr Pathol. 1990 Nov;56(3):300-11. doi: 10.1016/0022-2011(90)90116-n.
The histopathology caused by three ascoviruses isolated respectively from Heliothis zea, Spodoptera frugiperda, and Trichoplusia ni was studied in the host species from which the viruses were isolated originally, or in the case of the H. zea isolate, in H. virescens. In all three isolates, infected cells and virion-containing vesicles in the hemolymph were observed by 3 days postinoculation. The isolates from H. zea and T. ni exhibited relatively broad tissue tropisms infecting the tracheal matrix, epidermis, and connective tissue, and in the latter isolate, the fat body. Although considered variants of the same virus, these isolates varied slightly in their tissue tropism in that the isolate from H. zea replicated more extensively in the epidermis. The isolate from T. ni replicated in the fat body during early stages of disease, but not in advanced stages, and was not as common in the epidermis as the isolate from H. zea. The isolate from S. frugiperda replicated only in the fat body and completely destroyed this tissue by 12 days postinoculation. The progression of disease within the tissues was correlated with a rise in the concentration of virion-containing vesicles in the hemolymph of all three isolates. Vesicle concentrations rose from 10(7) on day 2 to 10(8)/ml of hemolymph on day 9, plateaued for 5-7 days, and then declined gradually through day 20. These results indicate that the chronic nature of the diseases caused by ascoviruses is due to the limited degree to which they infect major tissues (isolates from T. ni and H. zea) or the infection of tissues less essential to the maintenance of larval life (isolate from S. frugiperda).
分别从玉米螟、草地贪夜蛾和粉纹夜蛾中分离出的三种浓核病毒所引起的组织病理学，在最初分离出病毒的宿主物种中进行了研究，对于从玉米螟中分离出的病毒，研究是在绿铃夜蛾中进行的。在所有三种分离物中，接种后3天可观察到感染细胞和血淋巴中含病毒粒子的囊泡。从玉米螟和粉纹夜蛾中分离出的病毒表现出相对广泛的组织嗜性，感染气管基质、表皮和结缔组织，对于后者分离物，还感染脂肪体。尽管被认为是同一病毒的变体，但这些分离物在组织嗜性上略有不同，即从玉米螟中分离出的病毒在表皮中复制更广泛。从粉纹夜蛾中分离出的病毒在疾病早期在脂肪体中复制，但在晚期不复制，并且在表皮中不如从玉米螟中分离出的病毒常见。从草地贪夜蛾中分离出的病毒仅在脂肪体中复制，并在接种后12天完全破坏该组织。所有三种分离物的组织内疾病进展与血淋巴中含病毒粒子囊泡浓度的升高相关。囊泡浓度从第2天的10⁷上升到第9天的10⁸/毫升血淋巴，稳定5 - 7天，然后在第20天逐渐下降。这些结果表明，浓核病毒引起的疾病的慢性性质是由于它们感染主要组织的程度有限（粉纹夜蛾和玉米螟的分离物）或感染对维持幼虫生命不太重要的组织（草地贪夜蛾的分离物）。
