Cloning and sequencing of three new putative toxin genes from Clostridium bifermentans CH18

Three new open reading frames were found downstream from cbm71, a toxin gene from Clostridium bifermentans malaysia (Cbm) strain CH18. The first one (91 bp downstream) called cbm72, is 1857 bp long and encodes a 71 727-Da protein (Cbm72) with a sequence similar to that of Bacillus thuringiensis delta-endotoxins. This protein shows no significant toxicity to mosquito larvae. The two others, cbm17.1 (462 bp) and cbm17.2 (459 bp), are copies of the same gene encoding Cbm P18 and P16 polypeptides and located 426 bp and 1022 bp downstream from cbm72, respectively. They encode 17 189-Da and 17 451-Da proteins with sequences 44.6% similar to that of Aspergillus fumigatus hemolysin; however, they were not hemolytic in the conditions tested. (C) 1998 Elsevier Science B.V. All rights reserved.