Evidence for non-ribosomal peptide synthetase production of cereulide (the emetic toxin) in Bacillus cereus.
Little is known about the process whereby the emetic toxin (or cereulide) of Bacillus cereus is produced. Two cereulide-producing strains of B. cereus were cloned and sequenced following polymerase chain reaction (PCR) amplification with primers that were specific for conserved regions of non-ribosomal peptide synthetase (NRPS) genes. The cloned regions of the B. cereus strains were highly homologous to conserved regions of other peptide synthetase nucleotide sequences. Primers were designed for two variable regions of the NRPS gene sequence to ensure specificity for the emetic strains. A total of 86 B. cereus strains of known emetic or non-emetic activity were screened using these primers. All of the emetic strains (n=30) displayed a 188 bp band following amplification and gel electrophoresis. We have developed an improved method of identifying emetic strains of B. cereus and provided evidence that cereulide is produced by peptide synthetases.
Horwood
Paul F
PF
Department of Microbiology and Immunology, James Cook University, Townsville, Qld 4816, Australia. paul.horwood@dpi.qld.gov.au
Burgess
Graham W
GW
Oakey
H Jane
HJ
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001409:Bacillus cereus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D001427:Bacterial Toxins / Q000096:biosynthesis*; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000737:chemistry / Q000302:isolation & purification; D047630:Depsipeptides / Q000096:biosynthesis*; D008969:Molecular Sequence Data; D046908:Peptide Biosynthesis, Nucleic Acid-Independent; D010453:Peptide Synthases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D017434:Protein Structure, Tertiary; D012680:Sensitivity and Specificity; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
D001427:Bacterial Toxins; D004269:DNA, Bacterial; D047630:Depsipeptides; C089294:cereulide; D010453:Peptide Synthases; C104385:non-ribosomal peptide synthase