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Genetics Research International
Volume 2012, Article ID 543286, 9 pages
Research Article

Sequence Analysis of Inducible Prophage phIS3501 Integrated into the Haemolysin II Gene of Bacillus thuringiensis var israelensis ATCC35646

1UMR1319 Micalis, CRJ Institut National de la Recherche Agronomique, Bat. 440, Domaine de Vilvert, F-78352 Jouy-en-Josas, France
2Sécurité et Qualité des Produits d’Origine Végétale, UMR408, INRA Université d’Avignon, 84914 Avignon Cedex 9, France

Received 26 August 2011; Accepted 30 November 2011

Academic Editor: Tomaso Patarnello

Copyright © 2012 Bouziane Moumen et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Diarrheic food poisoning by bacteria of the Bacillus cereus group is mostly due to several toxins encoded in the genomes. One of them, cytotoxin K, was recently identified as responsible for severe necrotic syndromes. Cytotoxin K is similar to a class of proteins encoded by genes usually annotated as haemolysin II (hlyII) in the majority of genomes of the B. cereus group. The partially sequenced genome of Bacillus thuringiensis var israelensis ATCC35646 contains several potentially induced prophages, one of them integrated into the hlyII gene. We determined the complete sequence and established the genomic organization of this prophage-designated phIS3501. During induction of excision of this prophage with mitomycin C, intact hlyII gene is formed, thus providing to cells a genetic ability to synthesize the active toxin. Therefore, this prophage, upon its excision, can be implicated in the regulation of synthesis of the active toxin and thus in the virulence of bacterial host. A generality of selection for such systems in bacterial pathogens is indicated by the similarity of this genetic arrangement to that of Staphylococcus aureus   -haemolysin.