Activity of digestive proteinases and carbohydrases in the alimentary tract of the fig leaf roller, Choreutis nemorana Hübner (Lepidoptera: Choreutidae)

Abstract

.The fig leaf roller or Fig-tree Skeletoniser, Choreutis nemorana (Lep.: Choreutidae), is a destructive pest of fig trees found in some fig-growing areas of Iran. The larvae feed on the upper level of leaves, near the main vein. In this study, digestive carbohydrases including α-glucosidase, β-glucosidase, α-galactosidase, β-galactosidase and proteinases including trypsin, chymotrypsin and elastase were investigated. The results showed that the carbohydrases were present in the alimentary tracts of the pest. Optimum pH for α-glucosidase and β-glucosidase activity was at pH 6.0 and 7.0, respectively. Maximum activity of α-galactosidase and β-galactosidase occurred at pH 6.0. Total proteolitic activity against the substrate azocasein was optimally occurred at pH 10.0. The greatest activity of trypsin, chymotrypsin and elastase was determined at pH 10.0, 11.0 and 11.0, respectively. Zymogram analyses using nitrocellulose membrane revealed two trypsin isoforms in which one of them was completely inhibited by Soybean Kunitz inhibitor and the other was notably inhibited.

Keywords:

• carbohydrases
• proteinases
• native-PAGE
• nitrocellulose
• Choreutis nemorana