Mohd Amir F Abdullah

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The insecticidal crystal proteins produced by Bacillus thuringiensis (Bt) are broadly used to control insect pests with agricultural importance. The cadherin Bt-R(1) is a binding protein for Bt Cry1A toxins in midgut epithelia of tobacco hornworm (Manduca sexta). We previously identified the Bt-R(1) region most proximal to the cell membrane (CR12-MPED) as(More)
The Cry3Aa and Cry3Bb insecticidal proteins of Bacillus thuringiensis are used in biopesticides and transgenic crops to control larvae of leaf-feeding beetles and rootworms. Cadherins localized in the midgut epithelium are identified as receptors for Cry toxins in lepidopteran and dipteran larvae. Previously, we discovered that a peptide of a toxin-binding(More)
Novel Bacillus thuringiensis subsp. israelensis (Bti) Cry4Ba toxin-binding proteins have been identified in gut brush border membranes of the Aedes (Stegomyia) aegypti mosquito larvae by combining 2-dimensional gel electrophoresis (2DE) and ligand blotting followed by protein identification using mass spectrometry and database searching. Three alkaline(More)
Aminopeptidase N (APN) type proteins isolated from several species of lepidopteran insects have been implicated as Bacillus thuringiensis (Bt) toxin-binding proteins (receptors) for Cry toxins. We examined brush border membrane vesicle (BBMV) proteins from the mosquito Anopheles quadrimaculatus to determine if APNs from this organism would bind(More)
A midgut cadherin AgCad1 cDNA was cloned from Anopheles gambiae larvae and analyzed for its possible role as a receptor for the Cry4Ba toxin of Bacillus thuringiensis strain israelensis. The AgCad1 cadherin encodes a putative 1735-residue protein organized into an extracellular region of 11 cadherin repeats (CR) and a membrane-proximal extracellular domain(More)
Bacillus thuringiensis mosquitocidal toxin Cry4Ba has no significant natural activity against Culex quinquefasciatus or Culex pipiens (50% lethal concentrations [LC(50)], >80,000 and >20,000 ng/ml, respectively). We introduced amino acid substitutions in three putative loops of domain II of Cry4Ba. The mutant proteins were tested on four different species(More)
Improvements in the mosquitocidal activity of Bacillus thuringiensis Cry19Aa were achieved by protein engineering of putative surface loop residues in domain II through rational design. The improvement of Aedes toxicity in Cry19Aa was 42,000-fold and did not affect its toxicity against Anopheles or Culex.
BACKGROUND Specific Bacillus thuringiensis Berliner (Bt) toxins are effective against a narrow spectrum of species. While specificity is an advantage for limiting adverse effects on non-target organisms, it is also the primary drawback of Bt's application for controlling multiple pest species in agriculture, forestry and other areas. Recently, it was(More)
A peptide from cadherin AgCad1 of Anopheles gambiae larvae was reported as a synergist of Bacillus thuringiensis subsp. israelensis Cry4Ba's toxicity to the Anopheles mosquito (G. Hua, R. Zhang, M. A. Abdullah, and M. J. Adang, Biochemistry 47:5101-5110, 2008). We report that CR11 to the membrane proximal extracellular domain (MPED) (CR11-MPED) and a longer(More)
The Cry proteins produced by Bacillus thuringiensis (Bt) are the most widely used biopesticides effective against a range of crop pests and disease vectors. Like chemical pesticides, development of resistance is the primary threat to the long-term efficacy of Bt toxins. Recently discovered cadherin-based Bt Cry synergists showed the potential to augment(More)