title: Quantitative analysis of cereulide, an emetic toxin of Bacillus cereus, by using rat liver mitochondria.
abstract: An emetic toxin cereulide, produced by Bacillus cereus, causes emetic food poisonings, but a method for quantitative measurement of cereulide has not been well established. A current detection method is a bioassay method using the HEp-2 cell vacuolation test, but it was unable to measure an accurate concentration. We established a quantitative assay for cereulide based on its mitochondrial respiratory uncoupling activity. The oxygen consumption in a reaction medium containing rat liver mitochondria was rapid in the presence of cereulide. Thus uncoupling effect of cereulide on mitochondrial respiration was similar to those of uncouplers 2,4-dinitrophenol (DNP), carbonylcyanide m-chlorophenylhydrazone (CCCP), and valinomycin. This method gave constant results over a wide range of cereulide concentrations, ranging from 0.05 to 100 microg/ml. The minimum cereulide concentration to detect uncoupled oxygen consumption was 50 ng/ml and increased dose-dependently to the maximum level. Semi-log relationship between the oxygen consumption rate and the cereulide concentration enables this method to quantify cereulide. The results of this method were highly reproducible as compared with the HEp-2 cell vacuolation test and were in good agreement with those of the HEp-2 cell vacuolation test. The enterotoxin of B. cereus or Staphylococcus aureus did not show any effect on the oxygen consumption, indicating this method is specific for the identification of cereulide as a causative agent of emetic food poisonings.
authors.affiliation: Department of Medical Technology, Nagoya University Graduate School of Health Science, Nagoya, Aichi, Japan.
authors.forename: Kumiko
authors.initials: K
authors.lastname: Kawamura-Sato
authors.forename: Yumi
authors.initials: Y
authors.lastname: Hirama
authors.forename: Norio
authors.initials: N
authors.lastname: Agata
authors.forename: Hideo
authors.initials: H
authors.lastname: Ito
authors.forename: Kenzo
authors.initials: K
authors.lastname: Torii
authors.forename: Akira
authors.initials: A
authors.lastname: Takeno
authors.forename: Tadao
authors.initials: T
authors.lastname: Hasegawa
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Shimomura
authors.forename: Michio
authors.initials: M
authors.lastname: Ohta
mesh_terms: D019297:2,4-Dinitrophenol / Q000494:pharmacology; D000818:Animals; D001409:Bacillus cereus / Q000254:growth & development / Q000378:metabolism*; D001427:Bacterial Toxins / Q000032:analysis* / Q000302:isolation & purification / Q000633:toxicity*; D001681:Biological Assay; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000031:analogs & derivatives* / Q000494:pharmacology; D002460:Cell Line; D019069:Cell Respiration / Q000187:drug effects; D047630:Depsipeptides / Q000032:analysis* / Q000302:isolation & purification / Q000633:toxicity*; D004768:Enterotoxins / Q000633:toxicity; D005516:Food Microbiology; D005517:Foodborne Diseases / Q000209:etiology; D006801:Humans; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008930:Mitochondria, Liver / Q000187:drug effects* / Q000378:metabolism; D010101:Oxygen Consumption / Q000187:drug effects; D051381:Rats; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013211:Staphylococcus aureus; D014475:Uncoupling Agents / Q000494:pharmacology; D014634:Valinomycin / Q000494:pharmacology
chemical_list: D001427:Bacterial Toxins; D047630:Depsipeptides; D004768:Enterotoxins; D014475:Uncoupling Agents; C089294:cereulide; D014634:Valinomycin; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D019297:2,4-Dinitrophenol