Evidence for a chromosomally determined mesenterocin, a bacteriocin produced by Leuconostoc mesenteroides subsp....

Mesenterocin, a small anti-listerial peptide of 3.5 kDa produced by Leuconostoc mesenteroides subsp. mesenteroides OZ at the end of exponential growth was inactivated by proteolytic enymes, stable to cold storage (4 °C for 3 d), heat, organic solvents and surfactants, and exhibited maximum bactericidal mode of activity in the pH range 3 to 10. Although Leu. mesenteroides subsp. mesenteroides OZ harboured plasmids ranging in size from 3.6 to 9.7 kbp, no evidence was obtained indicating that mesenterocin was under the control of extrachromosomal plasmids because loss of bacteriocin production following plasmid curing experiments could not be correlated with plasmid loss and the lack of detectable plasmids suggested a chromosomal location for the genetic determinants of mesenterocin. To determine its chromosomal location, genetic determinants of the bacteriocin of Leu. mesenteroides subsp. mesenteroides OZ were tested with previously described bacteriocins of the Leuconostocs through PCR and results of PCR indicated that the gene for mesenterocin activity is located on the chromosome. No papers have been published, to the best of our knowledge, on chromosomal location of bacteriocin of Leuconostoc species. Association of meat spoilage with bacteriocin producing heterofermentative Leu. mesenteroides subsp. mesenteroides OZ is also suggested.