人参总皂苷对粘虫体内蛋白质含量及消化酶活性的影响

Effect of total ginsenoside on content of protein and activity of digestive enzyme of Mythimna separata larvae

目的:测定人参总皂苷对粘虫Mythimna separata体内蛋白质总含量及消化酶(纤维素酶和α-淀粉酶)活性的影响,探讨人参总皂苷的生态学作用。方法:在室内模拟粘虫的自然生长条件,采用载毒叶碟法饲喂4龄粘虫,通过Folin-酚试剂盒法测定粘虫体内蛋白质总含量,二硝基水杨酸法测定α-淀粉酶活性,滤纸法测定纤维素酶活性。结果:人参总皂苷能够显著降低粘虫体内蛋白质总含量,对粘虫体内消化酶(纤维素酶和α-淀粉酶)活性具有抑制作用,并且差异性显著。处理组蛋白质总含量、纤维素酶和α-淀粉酶活性显著低于对照组,且参总皂苷对α-淀粉酶和纤维素酶活性的抑制率与人参总皂苷浓度呈正相关,即20 g.L-1组>10 g.L-1组>5 g.L-1组。结论:人参总皂苷对粘虫体内蛋白质含量和消化酶活性的抑制,可能是引起粘虫表现拒食和生长发育不良的重要原因之一。

Objective： This study aims to reveal the effect of total ginsenoside on the protein content and digestive enzyme activities of 4th-instar Mythimna separata larvae, including α-amylase and cellulose, and explore the ecological function of total ginsenoside. Method： While simulating natural growing condition indoors, 4th-instar M. separata larvae were fed by poison leaf disk method. The protein content was tested by Lowry Protein Assay Kit method, the activity of α-amylase was measured by dinitrosalicylic acid test, and the activity of cellulase was determined by the filter paper method. Result： The total ginsenoside could reduce the content of protein of 4th-instar M. separata larvae significantly, and the activity of digestive enzyme, including α-amylase and cellulase. The protein content, α-amylase and cellulase activity of treatments were obviously lower than that of the control. Inhibition ratio of α-amylase and cellulase activity was positively correlated with total ginsenoside concentration： i.e. 20 g·L-1〉10 g·L-1〉5 g·L-1. Conclusion： The results suggest that the inhibition effect of total ginsenoside on protein content and digestive enzymes may be one of the causes to antifeedant and dysplasia of M. separata larvae.