Without bacteriocin addition, the final OD600 values were about 1.1 ± 0.1 for B. cereus, 0.8 ± 0.1 for B. subtilis. All experiments were performed in triplicate. Inhibition curves were made by plotting OD600 at the end of exponential phase in the case of the non treated strain versus bacteriocin concentration.
The minimal inhibitory concentration values were determined from the inhibition curves by interpolation. The lowest concentration of bacteriocin at which less than 1% of the total increase in the OD600, measured in the absence of bacteriocin, had occurred, was taken as the MIC value. The MIC values of AS-48, nisin and bacitracin for B. cereus ATCC14579 were 2.5 μg/ml, 5 μg/ml and 50 μg/ml, respectively. Acknowledgements This work was supported by the Spanish Ministry of Education
(research project AGL2008-01553/ALI). Vactosertib research buy M.J.G. was financially supported by the Research Programme of the University of Jaén, and the Research Plan of the Junta de Andalucía (research group AGR230, project P05-AGR-107), A.T.K. by grant 818.02.004 from ALW-NWO Open programma and O.P.K. by ALW-NWO Middelgroot support. This project was carried out within the research programme of the Kluyver Centre for Genomics of Industrial Fermentation which is part of the Netherlands Genomics Initiative/Netherlands Organization for Scientific Research. References 1. Granum PE, Lund T:Bacillus cereus and its food poisoning toxins. FEMS Microbiol Lett 1997, 157:223–228.CrossRefPubMed 2. Granum PE:Bacillus LDK378 nmr cereus. Food Microbiology Fundamentals and applications 2 Edition (Edited by: Doyle MP, Beuchat LR, Montville TJ). Washington D C, ASM Press 2009, 373–381. 3. Cleveland J, Montville TJ, Nes IF, Chikindas ML: Bacteriocins: safe, natural antimicrobials for food preservation. Int Oxymatrine J Food Microbiol 2001, 71:1–20.CrossRefPubMed 4. Devlieghere F, Vermeiren L, Debevere J: New preservation technologies: Possibilities and limitations. Int Dairy J 2004, 14:273–285.CrossRef 5. Galvez A, Lucas Lopez R, Abriouel
H, CDK inhibitor Valdivia E, Ben Omar N: Application of bacteriocins in the control of foodborne pathogenic and spoilage bacteria. Crit Rev Biotechnol 2008, 28:125–152.CrossRefPubMed 6. Jack RW, Tagg JR, Ray B: Bacteriocins of gram-positive bacteria. Microbiol Rev 1995, 59:171–200.PubMed 7. Franz CM, van Belkum MJ, Holzapfel WH, Abriouel H, Galvez A: Diversity of enterococcal bacteriocins and their grouping in a new classification scheme. FEMS Microbiol Rev 2007, 31:293–310.CrossRefPubMed 8. Samyn B, Martinez-Bueno M, Devreese B, Maqueda M, Galvez A, Valdivia E, Coyette J, Van Beeumen J: The cyclic structure of the enterococcal peptide antibiotic AS-48. FEBS Lett 1994, 352:87–90.CrossRefPubMed 9. Sanchez-Barrena MJ, Martinez-Ripoll M, Galvez A, Valdivia E, Maqueda M, Cruz V, Albert A: Structure of bacteriocin AS-48: from soluble state to membrane bound state. J Mol Biol 2003, 334:541–549.CrossRefPubMed 10.