We have evaluated the binding of Bacillus thuringiensis Cry toxins to aminopeptidase N (APN) purified from Lymantria dispar (gypsy moth) brush border membrane vesicle (BBMV). CryIAc toxin bound strongly to APN, while either the structurally related CryIAa and CryIAb toxins or CryIC, CryIIA, and CryIIIA toxins showed weak binding to APN. An in vitro competition binding study demonstrated that th...

Two different 30-nucleotide regions of the cryIAc insecticidal protoxin gene from Bacillus thuringiensis were randomly mutagenized. One region was within one of seven amphipathic helices believed to be important for the formation of ion channels. There was no loss of toxicity for three test insects by any of 27 mutants, a result similar to that obtained previously for mutations within another s...

The Egyptian Bacillus thuringiensis isolate (M5) produce crystal proteins that is toxic against insects was irradiated with UV light to induce mutants. Upon testing 10 of the resulting mutants for their toxicity against cotton leafworm larvae, the three mutants 62, 64 and 85 proved to be the most toxic ones. Upon testing these mutants along with their parental isolate by SDS-PAGE analysis of sp...

Somatic embryos of jack, a Glycine max (L.) Merrill cultivar, were transformed using microprojectile bombardment with a synthetic Bacillus thuringiensis insecticidal crystal protein gene (Bt cryIAc) driven by the 35S promoter and linked to the HPH gene. Approximately 10 g of tissue was bombarded, and three transgenic lines were selected on hygromycin-containing media and converted into plants. ...

Lepidopteran types of podborer and homopteran aphid insects are damaging pests of chickpea. CryIAc toxins are established control agents for podborers but do not or only slightly affect homopteran (sucking) insects. However, certain plant lectins are known for their power of killing aphids. Bioassay experiments carried out in our laboratory with lectins isolated from garlic leaves have already ...

Bollgard cotton (Gossypium hirsutum L.) containing the CryIAc endotoxin of Bacillus thuringiensis Berliner became commercially available to cotton producers in 1996. Bollgard cultivars since that time have provided excellent control of the tobacco budworm, Heliothis virescens F., for growers in Arkansas. Control of bollworm, Helicoverpa zea (Boddie), and other lepidopterous pests has been less ...