Transgenic corn expressing the Bacillus thuringiensis Cry1Ab gene is highly insecticidal to Ostrinia nubilalis (European corn borer) larvae. We ascertained whether Cry1F, Cry9C, or Cry9E recognizes the Cry1Ab binding site on the O. nubilalis brush border by three approaches. An optical biosensor technology based on surface plasmon resonance measured binding of brush border membrane vesicles (BB...

A phage repertoire was constructed using antibody genes from the bone marrow and the spleen of a rabbit immunized with Cry1Ab toxin. Biopanning against either the Cry1Ab toxin or a domain II loop 3 synthetic peptide resulted in the identification of monoclonal antibodies in scFv format. They inhibited binding and toxicity of Cry1Ab toxin against Manduca sexta. Toxin overlay assays, using the sc...

The cadherin protein Bt-R(1a) is a receptor for Bacillus thuringiensis Cry1A toxins in Manduca sexta. Cry1Ab toxin is reported to bind specific epitopes located in extracellular cadherin repeat (CR) 7 and CR11 on Bt-R(1) (Gomez, B., Miranda-Rios, J., Riudino-Pinera, E., Oltean, D. I., Gill, S. S., Bravo, A., and Soberon, M. (2002) J. Biol. Chem. 277, 30137-30143; Dorsch, J. A., Candas, M., Grik...

Tritrophic interactions between Mythimna separata, its tachinid parasite Exorista civilis and the Cry1Ab were examined. Although 6th instar M. separata mortality increased with increasing Cry1Ab concentration, some tolerance was evident. Likewise, parasitization by E. civilis resulted in only 18% host mortality. However, combination of Cry1Ab and E. civilis parasitization resulted in a signific...

Exposure to Bacillus thuringiensis (Bt) toxins in low- and moderate-dose transgenic crops may induce sublethal effects and increase the rate of Bt resistance evolution, potentially compromising control efficacy against target pests. We tested this hypothesis using the fall armyworm Spodoptera frugiperda, a major polyphagous lepidopteran pest relatively tolerant to Bt notorious for evolving fiel...

The modified truncated Bt-cry1Ab gene of Bacillus thuringiensis has been used for the development and selection of over expressing transgenic events in a commercially important variety of tomato (Solanum lycopersicum L.) by Agrobacterium-mediated leaf-disc transformation procedure. The integration and inheritance of cry1Ab gene in T0 transgenic plants and their progenies were determined by PCR,...

The distribution of Cry1Ab toxin was detected in the leaves of genetically modified maize of genetic event MON 810 by enzyme-linked immunosorbent assay. Cry1Ab toxin contents in the leaves at reproductive (milk, R3) phenological stage were measured to be between 3,878 and 11,148 ng Cry1Ab toxin/g fresh weight. Toxin content was significantly lesser (significant difference (SD) = 1,823 ng Cry1Ab...

The relationship between the mRNA level and the corresponding protein level of the cry1Ab/c gene is not well characterized in transgenic rice (Bt-ShanYou63). In this study, we compared cry1Ab/c mRNA and its protein expression in leaves at different growth stages in Bt-ShanYou63 rice. The results demonstrated that both cry1Ab/c mRNA and its protein levels changed at all of the growth stages. The...

Heritability of Chilo suppressalis (Walker) tolerance to the Cry1Ab toxin of Bacillus thuringiensis Berliner was estimated using a half-sibling design. Artificial diet with and without Cry1Ab was infested with progenies of 20 males, each mated with 2 females, and mortality was scored 5 d after infestation. The progeny of each female was reared and scored separately. Mean mortality of the 20 fam...