The Food and Environment Research Agency, Sand Hutton, York YO41 1LZ, United Kingdom.
J Invertebr Pathol. 2010 May;104(1):51-7. doi: 10.1016/j.jip.2010.01.010. Epub 2010 Feb 1.
The precise mechanisms underlying Bacillus thuringiensis-mediated killing of pest insects are not clear. In some cases, death may be due to septicaemia caused by Bt and/or gut bacteria gaining access to the insect haemocoel. Since insects protect themselves from microbes using an array of cellular and humoral immune defences, we aimed to determine if a recombinant immunosuppressive wasp venom protein (rVPr1) could increase the susceptibility of two pest Lepidoptera (Lacanobia oleracea and Mamestra brassicae) to Bt. Bio-assays indicated that injection of 6 microl of rVPr1 into the haemocoel of both larvae caused similar levels of mortality (less than 38%). On the other hand, the LD(30-40) of Bt for M. brassicae larvae was approximately 20 times higher than that for L. oleracea larvae. Furthermore, in bio-assays where larvae were injected with rVPr1, then fed Bt, a significant reduction in survival of larvae for both species occurred compared to each treatment on its own (P<0.001); and for L. oleracea larvae, this effect was more than additive. The results are discussed within the context of insect immunity and protection against Bt.
苏云金芽孢杆菌介导的害虫致死的精确机制尚不清楚。在某些情况下，死亡可能是由于 Bt 和/或肠道细菌进入昆虫血腔引起的败血症。由于昆虫使用一系列细胞和体液免疫防御来保护自己免受微生物的侵害，我们旨在确定重组免疫抑制蜂毒液蛋白（rVPr1）是否可以增加两种害虫鳞翅目（Lacanobia oleracea 和 Mamestra brassicae）对 Bt 的敏感性。生物测定表明，向两种幼虫的血腔注射 6 微升 rVPr1 会导致相似水平的死亡率（低于 38%）。另一方面，Bt 对 M. brassicae 幼虫的 LD（30-40）比 L. oleracea 幼虫高约 20 倍。此外，在向幼虫注射 rVPr1 然后喂食 Bt 的生物测定中，与每种处理单独处理相比，两种物种的幼虫存活率均显著降低（P<0.001）；对于 L. oleracea 幼虫，这种效果超过了相加效应。结果在昆虫免疫和对 Bt 的保护的背景下进行了讨论。
