We developed sugarcane plants with improved resistance to the sugarcane borer, Diatraea saccharalis (F). An expression vector pGcry1Ac0229, harboring the cry1Ac gene and the selectable marker gene, bar, was constructed. This construct was introduced into the sugarcane cultivar FN15 by particle bombardment. Transformed plantlets were identified after selection with Phosphinothricin (PPT) and Bas...

Binding studies using (125)I-Cry1Ac and biotinylated Cry1Fa toxins indicate the occurrence of a common receptor for Cry1Ac, Cry1Fa, and Cry1Ja in Helicoverpa armigera, Helicoverpa zea, and Spodoptera exigua. Our results, along with previous binding data and the observed cases of cross-resistance, suggest that this pattern seems to be widespread among lepidopteran species.

Twelve local B. thuringiensis strains are used in the study, which previously isolated from the soil of seven governorates and characterized by their high toxicity against 2 instars larvae of cotton nd leafworm (Spodoptera littoralis). The PCR amplification analysis of the 12 Bt isolates revealed the presence of amplified fragments characteristic of five different cry genes. Results showed the ...

Bacillus thuringiensis crystal protein family (Cry) consists of a diverse group of proteins with activity against insects of different orders, such as the Lepidoptera members. Their primary action is to lyse midgut epithelial cells by inserting into the target membrane and forming pores. Among this group, members of Cry1A family are used worldwide for insect control, and their mode of action ha...

Transgenic crops producing Bacillus thuringiensis (Bt) toxins kill some key insect pests and can reduce reliance on insecticide sprays. Sustainable use of such crops requires methods for delaying evolution of resistance by pests. To thwart pest resistance, some transgenic crops produce 2 different Bt toxins targeting the same pest. This "pyramid" strategy is expected to work best when selection...

Bacillus thuringiensis produces large amounts of various pesticidal proteins during the stationary phase. In order to achieve a high yield and form crystals, some pesticidal proteins require the presence of other proteins. Helper protein P20 is required for efficient production of both the Cyt1A and Cry11A crystal proteins in B. thuringiensis subsp. israelensis. Although full-length Cry1 protox...

Nanobodies are the smallest natural fragments with useful properties such as high affinity, distinct paratope and high stability, which make them an ideal tool for detecting target antigens. In this study, we generated and characterized nanobodies against the Cry1Ac toxin and applied them in a biotin-streptavidin based double antibodies (nanobodies) sandwich-ELISA (DAS-ELISA) assay. After immun...

Aminopeptidase N purified from whole Manduca sexta midgut binds the Cry1Ac insecticidal toxin from Bacillus thuringiensis and this binding is inhibited by N-acetylgalactosamine (GalNAc). We have examined the membrane permeabilising activity of the Cry1Ac toxin using brush border membrane vesicles (BBMV) prepared from the anterior (A-BBMV) and posterior (P-BBMV) subregions of the M. sexta midgut...

Research on non-target effects of transgenic crop plants has focused primarily on bitrophic, tritrophic and indirect effects of entomotoxins from Bacillus thuringiensis, but little work has considered intergenerational transfer of Cry proteins. This work reports a lepidopteran (Chlosyne lacinia) taking up a Bt entomotoxin when exposed to sublethal or low concentrations, transferring the entomot...

AIMS Some Cry proteins produced by the soil bacterium Bacillus thuringiensis (Bt) or by transgenic Bt plants persist in agricultural soils for an extended period of time, which may pose a hazard for nontarget soil organisms. The aims of our study were to screen for soil fungi capable of degrading the Cry1Ac toxin and to identify the mechanisms that lead to the inactivation of this protein. ME...