| The enhancin named P96 is a part of the protein expressed by the full-lengthenhancin gene from TnGV in Escherichia coli. As a new kind of biologic synergist, ithas be primitively demonstrated that it can significantly increase the virulence ofBacillus thuringiensis(Bt) and Avermactins to Helicoverpa armigera. Based on that,further research was carried out armed at P96's scale of broad-spectrum.A recombinant enhancing protein from Trichoplusia ni granulovirus, expressed inEscherichia coli and named as P96, had been shown to increase the susceptibility ofbio-insecticides to insect pests significantly in the previous study. A series of bioassaywere carried out for estimating the bioactivities of P96. In this paper, several biologicalcharacters were clarified to provide further proofs for P96's activity and its application.The results were indicated in the following. Occlusion bodies formed by P96 werequite stable when expressed in E. coli, however, it could be dissolved effectively inNa2CO3 solution or in midgut digestive juice of the 5th instar larvae of cottonbollworm, Helicoverpa armigera, in vitro. According to SDS-PAGE, peritropicmembrane of cotton bollworm was decomposed clearly by P96. With the increase ofconcentration of P96, the mortality of cotton bollworm caused by nuclear polyhedrosisvirus increased till its saturation concentration, 6.76×105occlusionbodies/mL. Itsbioactivity was inhibited strongly by ethylene diaminetraacetic acid, which formed acomplex compound with the metal ion (Zn2+) in the protein. |
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