Specific Binding of Radiolabeled Cry1Fa Insecticidal Protein from Bacillus thuringiensis to Midgut Sites in Lepidopteran Species

摘要

Cry1Fa insecticidal protein was successfully radiolabeled with ~(125)I-Na. Specific binding to brush border membrane vesicles was shown for the lepidopteran species Ostrinia nubilalis , Spodoptera frugiperda , Spodoptera exigua , Helicoverpa armigera , Heliothis virescens , and Plutella xylostella . Homologous competition assays were performed to obtain equilibrium binding parameters ( K_(d) [dissociation constant] and R_(t) [concentration of binding sites]) for these six insect species.