TY  - JOUR
TI  - Cytotoxicity Assay for Detection of Cereulide Produced by Emetic Bacillus cereus
AU  - Frenzel , Elrike 
AU  - Ehling-Schulz, Monika 
VL  - 3
IS  - 2
PY  - 2013
DA  - 2013/01/20
SP  - e318
C1  - Bio-protocol 2013;3:e318
DO  - 10.21769/BioProtoc.318
UR  - https://doi.org/10.21769/BioProtoc.318
AB  - The emetic subgroup of Bacillus cereus strains produces cereulide, a dodecadepsipeptide (1.2 kDa), which is the causative agent of food poisonings. Cereulide is synthesized by a nonribosomal peptide synthetase (NRPS), the Ces-NRPS (Ehling-Schulz et al., 2006). Cereulide is a cyclic and lipophilic potassium ionophor structurally related to the macrolide antibiotic valinomycin. Both substances act on mitochondria by depolarization and uncoupling of ATP synthesis, and this effect (mitochondrial swelling) is used to quantify cereulide in a HEp-2 cell based viability assay.   In this protocol, which was modified from an assay published by Finlay et al. (1999), valinomycin is used as a reference standard for ionophor–induced cytotoxicity, because purified cereulide is not commercially available yet. This assay has been used to quantify cereulide amounts from different B. cereus mutants (Lücking et al., 2009; Frenzel et al., 2012) and to estimate cereulide levels extracted from foods (artificially) contaminated with B. cereus (Frenzel et al., 2011).
KW  - Cereulide
KW  - Bacillus cereus
KW  - Cytotoxicity assay
KW  - Cell culture
KW  - Food poisoning
JF  - Bio-protocol
SN  - 2331-8325
PB  - Bio-protocol LLC.
BIO101  - False