title: Towards novel Cry toxins with enhanced toxicity/broader: a new chimeric Cry4Ba / Cry1Ac toxin.
abstract: Attempts have been made to express or to merge different Cry proteins in order to enhance toxic effects against various insects. Cry1A proteins of Bacillus thuringiensis form a typical bipyramidal parasporal crystal and their protoxins contain a highly conserved C-terminal region. A chimerical gene, called cry(4Ba-1Ac), formed by a fusion of the N-terminus part of cry4Ba and the C-terminus part of cry1Ac, was constructed. Its transformation to an acrystalliferous B. thuringiensis strain showed that it was expressed as a chimerical protein of 116 kDa, assembled in spherical to amorphous parasporal crystals. The chimerical gene cry(4Ba-1Ac) was introduced in a B. thuringiensis kurstaki strain. In the generated crystals of the recombinant strain, the presence of Cry(4Ba-1Ac) was evidenced by MALDI-TOF. The recombinant strain showed an important increase of the toxicity against Culex pipiens larvae (LC50= 0.84 mg l-1± 0.08) compared to the wild type strain through the synergistic activity of Cry2Aa with Cry(4Ba-1Ac). The enhancement of toxicity of B. thuringiensis kurstaki expressing Cry(4Ba-1Ac) compared to that expressing the native toxin Cry4Ba, might be related to its a typical crystallization properties. The developed fusion protein could serve as a potent toxin against different pests of mosquitoes and major crop plants.
authors.affiliation: Laboratory of Biopesticides, Centre of Biotechnology of Sfax, University of Sfax, P.O. Box "1177", 3018, Sfax, Tunisia. raida.zribi@cbs.rnrt.tn.
authors.forename: Raida Zribi
authors.initials: RZ
authors.lastname: Zghal
authors.affiliation: Laboratory of Biopesticides, Centre of Biotechnology of Sfax, University of Sfax, P.O. Box "1177", 3018, Sfax, Tunisia.
authors.forename: Jihen
authors.initials: J
authors.lastname: Elleuch
authors.affiliation: Laboratoire de Microorganismes et de Biomolécules, Centre de Biotechnologie de Sfax, Université de Sfax, Sfax, Tunisia.
authors.forename: Mamdouh
authors.initials: M
authors.lastname: Ben Ali
authors.affiliation: Institut de Recherche pour le Développement (IRD), UMR MIVEGEC (UM1-UM2-CNRS 5290-IRD 224) Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle, Laboratoire de Lutte contre les Insectes Nuisibles (LIN), Montpellier, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Darriet
authors.affiliation: Research Group on Molecular and Cellular Screening Processes, Laboratory of Microorganisms and Biomolecules, Centre of Biotechnology of Sfax, Sfax, Tunisia.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Rebaï
authors.affiliation: Institut de Recherche pour le Développement (IRD), UMR MIVEGEC (UM1-UM2-CNRS 5290-IRD 224) Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle, Laboratoire de Lutte contre les Insectes Nuisibles (LIN), Montpellier, France.
authors.forename: Fabrice
authors.initials: F
authors.lastname: Chandre
authors.affiliation: Biological & Environmental Sciences Department, College of Arts and Sciences, Qatar University, P.O. Box: 2713, Doha, Qatar.
authors.forename: Samir
authors.initials: S
authors.lastname: Jaoua
authors.affiliation: Laboratory of Biopesticides, Centre of Biotechnology of Sfax, University of Sfax, P.O. Box "1177", 3018, Sfax, Tunisia.
authors.forename: Slim
authors.initials: S
authors.lastname: Tounsi
mesh_terms: D000818:Animals; D001413:Bacillus thuringiensis / Q000235:genetics* / Q000378:metabolism*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000633:toxicity*; D003465:Culex / Q000382:microbiology / Q000502:physiology; D004731:Endotoxins / Q000737:chemistry / Q000235:genetics* / Q000633:toxicity*; D015870:Gene Expression; D006460:Hemolysin Proteins / Q000737:chemistry / Q000235:genetics* / Q000633:toxicity*; D008970:Molecular Weight; D015202:Protein Engineering; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics* / Q000633:toxicity*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D016019:Survival Analysis; D014170:Transformation, Genetic
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; D011993:Recombinant Fusion Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis
keywords: Bacillus thuringiensis kurstaki; Chimerical protein Cry(4Ba-1Ac); Toxicity improvement to Culex pipiens