Binding Analyses of Bacillus thuringiensis Cry δ-Endotoxins Using Brush Border Membrane Vesicles of Ostrinia nubilalis

摘要: Transgenic corn expressing the Bacillus thuringiensis Cry1Ab gene is highly insecticidal to Ostrinia nubilalis (European borer) larvae. We ascertained whether Cry1F, Cry9C, or Cry9E recognizes binding site on O. brush border by three approaches. An optical biosensor technology based surface plasmon resonance measured of membrane vesicles (BBMV) injected over a immobilized Cry toxin. Preincubation with reduced BBMV Cry1Ab, whereas preincubation did not inhibit binding. Cry1F-coated was when were preincubated in Cry1F but Cry9C Cry9E. A radioligand approach 125 I-Cry1Ab toxin presence homologous (Cry1Ab) and heterologous (Cry1Ac, Cry9E) toxins. Unlabeled Cry1Ac effectively competed for ICry1Ab manner comparable itself. toxins BBMV. inhibited at concentrations greater than 500 nM. had low-level affinity site. Ligand blot analysis identified Cry1Ac, proteins The major signals ligand blots 145 kDa 154 kDa, strong signal present 220 weak 167 kDa. detected Anti-Manduca sexta aminopeptidase serum recognized 145, 154, anti-cadherin protein. speculate that isoforms cadherin serve as proteins. transgene commercial controls pest insect proposed model B. intoxication involves three-step process: activation, binding, pore formation. Activation refers specific proteolytic processing protein molecule midgut susceptible organism. This occurs through combination pH prote