Resistance of Insect to Pathogenic Viruses

蚕核多角体病毒（NPV）经蚕血淋巴孵育后灭活。失活活性位于通过5Kd分子量过滤器的部分，该活性的抑制剂存在于大于5Kd的部分。经热处理和蛋白酶处理后，该组分仍保持失活活性。我们还检测到谷胱甘肽使NPV失活，并正在分析血淋巴和其他化合物使NPV失活的机制。对斜纹夜蛾（Spodoptera litura Fab）感染的核多角体病毒（NPV）进行生物测定，发现随着幼虫年龄的增加，中位致死剂量（LD50）和中位致死时间（LT50）值均有所增加。幼虫。LD50值和LT50值随幼虫龄的增加而增加。即使在试验的最高剂量下，对孵化后11天以上的幼虫进行口服接种也未发生感染。然而，腹腔内注射NPV导致成熟幼虫因病毒感染而死亡，这可能是由于幼虫接近化蛹时肠道介导的屏障造成的。

Nucleopolyhedrovirus (NPV) of the silkworm was inactivated after incubation with the silkworm hemolymph. Inactivation activity was located in the fraction that passed a filter with 5 kd M.W.and inhibitors of that activity existed in the fraction with more than 5Kd. Inactivation activity was retained after heat and protease treatment of the fraction. We also detected that glutathion inactivated NPV and are analyzing inactivation mechanism of NPV by the hemolymph and other compounds.An increase in median lethal dose (LD50) and median lethal time (LT50) values with increased larval age was recorded in bioassay studies of the nucleopolyhedrovirus (NPV) infected Spodoptera litura Fab. larvae. The LD50 values and LT50 increase with increased larval age. Larvae those were more than 11-day-old after hatching was not infected through oral inoculation even at the highest dose of the trial. However, intrahaemocoelic injection of NPV into matured larvae resulted into death due to viral infection indicating a lack of susceptibility possibly due to gut mediated barrier that developed as the larvae approached pupation.