家蚕幼虫总蛋白酶和胰蛋白酶活性的测定

Determination of Total Protease and Trypsin Activity of Silkworm,Bombyx mori

为了调查家蚕幼虫总蛋白酶和胰蛋白酶活性,并探讨与丝氨酸蛋白酶基因表达之间的关系。对家蚕不同组织、不同时期、不同品种来源的样品进行了总蛋白酶和胰蛋白酶活性的检测。在Ysh品种中肠中的总蛋白酶和胰蛋白酶活性都高于丝腺,性别差异不显著,品种中Dazao和Ysh显著高于Y-1和C108;Ysh品种5龄3日中肠中的胰蛋白酶活性显著高于5龄7日,高浓度蜕皮激素(20E)处理后24 h中肠中胰蛋白酶活性下降幅度比较大,保幼激素处理后变化不显著。胰蛋白酶活性测定结果与SPs家族基因特异性的在中肠表达,5龄中期表达高于5龄末期,20 E处理后24 h出现下调表达的结果是一致的;不同品种酶活性的差异可能与生命力差异有关。为家蚕丝物质形成和积累提供了分子调控的参考依据。

To investigate total protease and trypsin activity and the relationship with the serine protease gene expression of silkworm,Bombyx mori,the total protease and trypsin activity of different tissue,developmental stages and silkworm varieties were tested. The results showed that two enzymic activity in midgut of Ysh variety were higher than in silkgland,and not predominance difference between the sexes. Two values in Ysh and Dazao were notablely higher than Y-1 and C108; In midgut of Ysh,the trypsin activity on fifth instar 3 was significantly higher than that on fifth instar 7 and displayed large decline after 24 h treatment by molting hormone（ 20E） and no change treatment by juvenile hormone. Trypsin activity was consistent with gene expression level of SPs family,the latter had a higher expression of midgut and a higher expression stage on mid-5th instar stage than on later-5th instar stage,as well as appeared a down regulation expression at 24 h post-20 E. Differences in enzyme activity may be associated with different varieties vitality. This provides the molecular regulation reference for the formation and accumulation of silk material in silkworm.