title: Chemodiversity of cereulide, the emetic toxin of Bacillus cereus.
abstract: Food-borne intoxications are increasingly caused by the dodecadepsipeptide cereulide, the emetic toxin produced by Bacillus cereus. As such intoxications pose a health risk to humans, a more detailed understanding on the chemodiversity of this toxin is mandatory for the reliable risk assessment of B. cereus toxins in foods. Mass spectrometric screening now shows a series of at least 18 cereulide variants, among which the previously unknown isocereulides A-G were determined for the first time by means of UPLC-TOF MS and ion-trap MS(n) sequencing, (13)C-labeling experiments, and post-hydrolytic dipeptide and enantioselective amino acid analysis. The data demonstrate a high microheterogeneity in cereulide and show evidence for a relaxed proof reading function of the non-ribosomal cereulide peptide synthetase complex giving rise to an enhanced cereulide chemodiversity. Most intriguingly, the isocereulides were found to differ widely in their cell toxicity correlating with their ionophoric properties (e.g., purified isocereulide A showed about 8-fold higher cytotoxicity than purified cereulide in the HEp-2 assay and induced an immediate breakdown of bilayer membranes). These findings provide a substantial contribution to the knowledge-based risk assessment of B. cereus toxins in foods, representing a still unsolved challenge in the field of food intoxications.
authors: Chair of Food Chemistry and Molecular Sensory Science, Technische Universität München, Lise-Meitner-Straße 34, 85354, Freising, Germany.
authors: Sandra
authors: S
authors: Marxen
authors: Timo D
authors: TD
authors: Stark
authors: Elrike
authors: E
authors: Frenzel
authors: Andrea
authors: A
authors: Rütschle
authors: Genia
authors: G
authors: Lücking
authors: Gabriel
authors: G
authors: Pürstinger
authors: Elena E
authors: EE
authors: Pohl
authors: Siegfried
authors: S
authors: Scherer
authors: Monika
authors: M
authors: Ehling-Schulz
authors: Thomas
authors: T
authors: Hofmann
mesh_terms: D001409:Bacillus cereus / Q000737:chemistry*; D001427:Bacterial Toxins / Q000032:analysis* / Q000633:toxicity; D002470:Cell Survival / Q000187:drug effects; D002851:Chromatography, High Pressure Liquid; D047630:Depsipeptides / Q000032:analysis* / Q000633:toxicity; D004639:Emetics / Q000032:analysis* / Q000633:toxicity; D056945:Hep G2 Cells; D006801:Humans; D013058:Mass Spectrometry
chemical_list: D001427:Bacterial Toxins; D047630:Depsipeptides; D004639:Emetics; C089294:cereulide