龟纹瓢虫卵黄蛋白的分子特性及发生动态

研究了龟纹瓢虫Propylea japonica (Thunberg) 卵黄蛋白的基本特性以及卵黄发生过程中卵黄蛋白的动态变化。PAGE和SDS-PAGE实验表明，龟纹瓢虫卵黄蛋白分子量为294.81±40.70 kD，并由分子量分别为144.68±0.03 kD和51.23±0.27 kD的两种亚基组成。对卵黄蛋白的氨基酸组成和含量分析发现，其必需氨基酸总量占57.48％，略高于非必需氨基酸，其中谷氨酸（Glu）含量最高，为15.26％；色氨酸（Trp）和蛋氨酸（Met）含量较低，分别为0.50％和0.11％。采用间接竞争ELISA法，系统测定了龟纹瓢虫成虫期脂肪体、血淋巴和卵巢中卵黄蛋白的动态变化，结果表明：脂肪体是卵黄原蛋白合成的场所，卵黄原蛋白的合成始于羽化后第2天；脂肪体、血淋巴和卵巢中卵黄原蛋白的滴度在羽化后第4天开始迅速上升，至成虫期的第8天左右达到高峰期。

Molecular characterization and dynamic analysis on vitellin of Propylea japonica ( Thunberg) (Coleoptera: Coccinellidae)

The characteristics of vitellin and its content in vitellogenesis were studied in Propylea japonica (Thunberg). The characterization of vitellin was carried out by PAGE and SDS-PAGE. The results indicated that vitellin had a molecular weight of approximately 294.81±40.70 kD and was composed of two subunits, whose molecular weights were 144.68±0.03 kD and 51.23±0.27 kD respectively. The content of essential amino acid was 57.48%, which was little higher than that of non-essential amino acid. The amino acid with the highest content in vitellin was Glu, its content was 15.26%; while contents of Trp and Met were very low, only 0.50% and 0.11%, respectively. Using indirect ELISA, the contents of vitellin in the fat body, haemolymph and ovary of P. japonica were detected. The results suggested that the vitellogenin was synthesized in fat body at the 2nd day after eclosion. The contents of vitellogenin in fat body, haemolymph and ovary increased quickly on the 4th day after eclosion and reached the peak stage approximately on the 8th day in adult stage.