Comparative phylogenetic and transcriptional analysis of the Bacillus cereus sensu lato enterotoxin genes nhe, hbl and cytK

B. cereus sensu lato was found to comprise seven genomospecies. Enterotoxin genes are distributed irregularly among them. Hbl, cytK and plcR evolved through frequent horizontal gene transfer, while nhe developed strictly vertical. Transcription of nhe and hbl is strain-specific, media-dependent and controlled by several regulators via exceptionally long 5' untranslated regions.