Some Biochemical Characters of Gut α-amylases of Anagasta kuehniella Zeller (Lepidoptera: Pyralidae) and Inhibitory Effects of Three Proteinaceous Extracts on Their Activities

Anagasta kuehniella Zeller (Lepidoptera: Pyralidae) causes the quality loss of the bread by feeding on flour. Disruption in insect’s digestive enzymes through transgenic plants, expressing enzyme inhibitors, is a methods of pest control. So, the aim of the current study was to investigate the inhibitory effects of proteinaceous extracts of two varieties of wheat (Sivand, Sardari) and Triticale against activity of digestive α-amylase of fourth (L4) and fifth (L5) instars larvae of A.kuehniella. Ammonium sulfate (70%) was used to extract proteins from seeds. The optimal temperature and pH of α-amylase activity was found 40°C and 10, respectively. The results showed that the highest dose of proteinaceous extracts of Sivand and Sardari (13 µg ml-1 protein) and Triticale (16 µg ml-1 protein) reduced the enzyme activity, 73.08%, 71.07% and 65.88% of L5 and 58.16%, 42.14% and 50.25% of L4, respectively. The lowest dose of proteinaceous extracts of Sivand and Sardari (0.812 µg ml-1 protein) and Triticale (1 µg ml-1 protein) inhibited the enzyme activity, 19.93%, 17.8% and 25.26% of L5 and 11.78%, 12.81% and 10.09% of L4, respectively. In the gel electrophoresis of enzyme without usage of inhibitors, one band was observed. At the highest dose of extracts, in the L5, amylase band disappeared and in the L4, waned band clearly. Band resolution was increased by reducing inhibitor dose. It was concluded that Sivand, Sardari and Triticale proteinaceous extracts can be used for management of A.kuehniella.