Zymogram analysis of partially purified protein from two leguminose seeds on protease activity of Indian meal moth, Plodia interpunctella Hübner (Lepidoptera: Pyralidae)

Plodia interpunctella Hübner (Indian meal moth) is a cosmopolitan pest that infests many strategic stored products such as pistachio, dried fruits, nuts, walnut and cereal grains. Plant Protease inhibitors have been shown to play inhibitory roles in proteolytic processes. The experiment was carried out was the inhibition effect of proteinaceous extracts obtained from two leguminose seeds, Senna (Cassia angustifolia) and Fenugreek (Trigonella foenum-graecum) on proteases activity of Indian meal moth, Plodia interpunctella Hübner (Lepidoptera: Pyralidae). Enzyme stability assay with 5 h pre incubation showed that Senna and Fenugreek seeds play maximum inhibitory role in pH of 7 and 12, respectively. A polyacrylamide gel technique was used to evaluate the proteolytic activity of larval midgut samples treated by inhibitors that were precipitated by purified fractions. The large numbers of thick bands in the control lines showed high proteolytic activity of larval midgut. The proteolytic activity was reduced by progress in purification process and the highest inhibitory effect was detected at the final stage of purification. Zymogram analysis of trypsin-like activity by gel overlay with nitrocellulose shown high power inhibitory of these two proteinaceous compounds. Tryptic bands were reduced by using Senna inhibitor fraction that purified by ion exchange chromatography. Usage of these two compounds is suggested for further studies in transgenic plants.