title: LC-MS analysis of the emetic toxin, cereulide, produced by Bacillus cereus.
abstract: A quantitative and chemical assay of cereulide produced in the cultures by some strains of Bacillus cereus was performed on a HPLC and a ESI electrospray ion trap mass analyzer, using the synthetic cereulide as a standard. All 20 strains of emetic B. cereus were found to produce 27 - 740 ng/ml of cereulide by the LC-MS analysis. In contrast, none of the 10 diarrheal strains produced it. 10(2) cfu/ml of the cereulide producible strain with a 210 ng/ml yield was inoculated into the 10% suspensions of 14 food products, and was incubated at 32°C for 24h. The B. cereus counts in the cultures grew in the order of 10(8) to 10(9) cfu/ml, although the bacteria could not grow in fruits, and the yields of cereulide ranged from 5.18μg in curry to 0.03μg/g of raw material and/or powder material, except for fruits. These culture supernatants were also tested for the biological activity in the HEp-2 cell culture assay. Consequently, a certain correlation was shown between the yields of cereulide and the HEp-2 vacuolation activities. In addition, the supernatants were administered i.p. to 5 Suncus marinus test animals. The emetic dose was calculated to be approximately 16μg/kg.
authors.affiliation: Laboratory of Hygiene, Kagawa Nutrition University, 3-9-1, Chiyoda, Sakado-shi, Saitama 350-0214, Japan.
authors.forename: Shigeko
authors.initials: S
authors.lastname: Ueda
authors.forename: Hajime
authors.initials: H
authors.lastname: Nakajima
authors.forename: Miki
authors.initials: M
authors.lastname: Iwase
authors.forename: Kunihiro
authors.initials: K
authors.lastname: Shinagawa
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Kuwabara
mesh_terms: D000818:Animals; D001409:Bacillus cereus / Q000378:metabolism*; D002460:Cell Line; D002623:Chemistry Techniques, Analytical; D002853:Chromatography, Liquid / Q000379:methods*; D047630:Depsipeptides / Q000032:analysis* / Q000633:toxicity; D004639:Emetics / Q000032:analysis* / Q000633:toxicity; D005516:Food Microbiology; D022781:Hepatocytes / Q000187:drug effects; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods*
chemical_list: D047630:Depsipeptides; D004639:Emetics; C089294:cereulide