Horizon 1 1 17 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES Applied Microbiology and Biotechnology 113-122 [+ erratum, vol. 101, no 14, p. 5949] Bacillus thuringiensis kurstaki Chimerical protein Cry(4Ba-1Ac) Toxicity improvement to Culex pipiens 2017 fdi:010068859 ENG Applied Microbiology and Biotechnology 0175-7598 ISI:000391365800009 1 10.1007/s00253-016-7766-3 https://www.documentation.ird.fr/hor/fdi:010068859 https://www.documentation.ird.fr/intranet/publi/depot/2017-08-25/010068859.pdf 101 Horizon (IRD) 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. 084 ; 020 ; 052 UR224 Tunisie