草地螟滞育幼虫的蛋白和核酸含量变化

为了阐明草地螟Loxostege sticticalis 滞育的分子调控基础， 本研究应用Trizol法、 DNA和蛋白质定量试剂盒、 SDS-PAGE电泳技术分别对进入滞育1， 2， 3和4个月、 解除滞育以及非滞育草地螟老熟幼虫中的核酸含量、 总蛋白含量和组分的变化进行了测定。结果表明： 滞育不同月份幼虫的总RNA含量显著低于非滞育幼虫的总RNA含量（P＜0.05）； 解除滞育幼虫的总RNA含量显著高于滞育2， 3和4个月的幼虫， 但仍显著低于非滞育的对照组。滞育不同月份、 非滞育以及解除滞育幼虫的总DNA含量没有显著差异（P＞0.05）。RNA/DNA比值随滞育的开始而显著下降， 随着滞育的结束而显著上升。滞育不同月份的幼虫总蛋白含量显著高于非滞育幼虫的总蛋白含量（P<0.05）， 但解除滞育与非滞育幼虫的总蛋白含量无显著差异。利用SDS-PAGE电泳分析发现滞育幼虫体内存在滞育关联蛋白， 蛋白条带在24 kDa左右， 但非滞育和已经解除滞育的幼虫则没有该蛋白条带。这些结果表明， 总RNA含量的降低、 RNA/DNA比值下降、 总蛋白含量的升高， 以及24 kDa蛋白的存在是草地螟幼虫滞育的主要生理特征。

Changes in protein and nucleic acid contents in diapause larvae of the beet webworm, Loxostege sticticalis ( Lepidoptera : Pyralidae)

To understand the molecular regulation of diapause in the beet webworm, Loxostege sticticalis L. , we analyzed the contents and compositions of proteins and nucleic acids in non-diapause larvae, diapausing larvae with the diapause duration of 1, 2, 3, and 4 months, and post-diapause larvae of this species by using Trizol method, DNA and protein quantitative kit, and SDS-PAGE technique. The results showed that the RNA content in the diapausing larvae with the diapause duration of 1 to 4 months was significantly lower than that of the non-diapause larvae. Although RNA content in the post-diapause larvae increased significantly as compared with that of the diapausing larvae with the diapause duration of 2, 3 and 4 months, it was significantly lower than that of the non-diapause larvae. The DNA content among these treatments was not significantly different, but the RNA/DNA ratio in the diapausing larvae with the diapause duration of 1 to 4 months was lower than that in the non-diapause and post-diapause larvae. The protein content in all the diapause larvae was significantly higher than that in the non-diapause larvae, but there was no significant difference between the non-diapause and the post-diapause larvae. A protein band of 24 kDa was found in the diapausing larvae with the diapause duration of 1 to 4 months but was not detected in the non-diapause and post diapause larvae by using the SDS-PAGE technique. These results suggest that the lower RNA content, the lower RNA/DNA ratio, and higher protein content, as well as the presence of 24 kDa-protein, are the major characteristics of the diapause larvae distinguishing from the non-diapause and post-diapause larvae of L. sticticalis.