title: The impact of the Bacillus subtilis SPB1 biosurfactant on the midgut histology of Spodoptera littoralis (Lepidoptera: Noctuidae) and determination of its putative receptor.
abstract: SPB1 is a Bacillus subtilis strain producing a lipopeptide biosurfactant. The insecticidal activity of this biosurfactant was evaluated against the Egyptian cotton leaf worm (Spodoptera littoralis). It displayed toxicity with an LC(50) of 251 ng/cm(2). The histopathological changes occurred in the larval midgut of S. littoralis treated with B. subtilis SPB1 biosurfactant were vesicle formation in the apical region, cellular vacuolization and destruction of epithelial cells and their boundaries. Ligand-blotting experiments with S. littoralis brush border membrane vesicles showed binding of SPB1 biosurfactant to a protein of 45 kDa corresponding to its putative receptor. The latter differs in molecular size from those recognized by Bacillus thuringiensis Vip3A and Cry1C toxins, commonly known by their activity against S. littoralis. This result wires the application of B. subtilis biosurfactant for effective control of S. littoralis larvae, particularly in the cases where S. littoralis will develop resistance against B. thuringiensis toxins.
authors.affiliation: Unit of Enzymes and Bioconversion, National School of Engineers of Sfax, University of Sfax, BP W, 3038 Sfax, Tunisia.
authors.forename: Dhouha
authors.initials: D
authors.lastname: Ghribi
authors.forename: Lobna
authors.initials: L
authors.lastname: Abdelkefi-Mesrati
authors.forename: Hanen
authors.initials: H
authors.lastname: Boukedi
authors.forename: Mouna
authors.initials: M
authors.lastname: Elleuch
authors.forename: Semia
authors.initials: S
authors.lastname: Ellouze-Chaabouni
authors.forename: Slim
authors.initials: S
authors.lastname: Tounsi
mesh_terms: D000818:Animals; D001412:Bacillus subtilis / Q000378:metabolism*; D001681:Biological Assay; D041981:Gastrointestinal Tract / Q000187:drug effects* / Q000473:pathology; D019476:Insect Proteins / Q000378:metabolism; D007306:Insecticides / Q000378:metabolism / Q000633:toxicity*; D007814:Larva / Q000187:drug effects; D007928:Lethal Dose 50; D033902:Periplasmic Binding Proteins / Q000378:metabolism / Q000633:toxicity*; D010572:Pest Control, Biological / Q000379:methods; D011485:Protein Binding; D018411:Spodoptera / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D013501:Surface-Active Agents / Q000378:metabolism / Q000633:toxicity*
chemical_list: D019476:Insect Proteins; D007306:Insecticides; D033902:Periplasmic Binding Proteins; D013501:Surface-Active Agents; C044773:sulfate-binding protein, bacteria