title: Ephestia kuehniella tolerance to Bacillus thuringiensis Cry1Aa is associated with reduced oligomer formation.
abstract: The basis of the different susceptibility of Ephestia kuehniella to the Cry1Aa and Cry1Ac δ-endotoxins from Bacillus thuringiensis kurstaki BNS3 was studied. Both toxins bound specifically to the BBMV of E. kuehniella. The result of the ligand blot showed that Cry1Ac bound to three putative receptors of about 100, 65 and 80 kDa and Cry1Aa interacted only with a 100 kDa protein. Pronase digestion of the BBMV-bound toxins was used to analyze the toxin insertion. Both toxins inserted into the BBMV as monomers however, a 14 kDa peptide of α4-α5 which correspond to the oligomeric form of this peptide was detected in case of Cry1Ac only. Analysis of the in vitro oligomerisation of these toxins in the presence of the BBMV of E. kuehniella showed reduced oligomer formation in case of Cry1Aa in comparison with Cry1Ac. Taken together, these results strongly suggest that the difference of toxicity between Cry1Aa and Cry1Ac to E. kuehniella is due to a deficient oligomerisation of Cry1Aa.
authors.affiliation: Laboratory of Biopesticides, Centre of Biotechnology of Sfax, P.O. Box "1177", 3018, Sfax, Tunisia; ERI de Biotecnología y Biomedicina (BIOTECMED), Universitat de València, 46-100, Burjassot, Spain.
authors.forename: Maissa
authors.initials: M
authors.lastname: Chakroun
authors.affiliation: Laboratory of Biopesticides, Centre of Biotechnology of Sfax, P.O. Box "1177", 3018, Sfax, Tunisia.
authors.forename: Sameh
authors.initials: S
authors.lastname: Sellami
authors.affiliation: ERI de Biotecnología y Biomedicina (BIOTECMED), Universitat de València, 46-100, Burjassot, Spain.
authors.forename: Juan
authors.initials: J
authors.lastname: Ferré
authors.affiliation: Laboratory of Biopesticides, Centre of Biotechnology of Sfax, P.O. Box "1177", 3018, Sfax, Tunisia.
authors.forename: Slim
authors.initials: S
authors.lastname: Tounsi
authors.affiliation: Laboratory of Biopesticides, Centre of Biotechnology of Sfax, P.O. Box "1177", 3018, Sfax, Tunisia. Electronic address: souad.rouis@cbs.rnrt.tn.
authors.forename: Souad
authors.initials: S
authors.lastname: Rouis
mesh_terms: D000818:Animals; D001413:Bacillus thuringiensis / Q000737:chemistry / Q000502:physiology*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity*; D004731:Endotoxins / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity*; D006460:Hemolysin Proteins / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity*; D007915:Lepidoptera / Q000187:drug effects / Q000382:microbiology* / Q000502:physiology; D011487:Protein Conformation; D055503:Protein Multimerization
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis
keywords: Cry1Ac; Ephestia kuehniella; Oligomerisation; Pronase