ACTION OF THE TWO COMPONENT BACTERIOCIN LACTOCIN 705 AGAINST LACTOBACILLUS PLANTARUM CRL 691

CUOZZO, S ; CASTELLANO , P; SESMA, F; VIGNOLO, G; R. RAYA

PROCEEDINGS OF ENPROMER

EMPROER

Año: 2001 vol. 3 p. 1861 - 1866

1666-1621

Lactocin705 is a two-component bacteriocin produced by Lactobacillus casei CRL 705, a strain isolated from dry fermented sausage. In this work, the mode of action of the two peptides, of 33 amino acid residues each and termed alfa and beta , has been evaluated against the indicator strain Lactobacillus plantarum CRL 691. Lactocin 705 has a bactericide effect om sensitive CRL 691 cells with a MIC of 45 nM. A different response was observed when the two peptides were added separately to a diluted supernatant of L. Casei CRL 705, which showed an intermediate level of inhibition on the growth of L. Plantarum CRL 691. While the beta peptide potentiated the antimicrobial effect of the diluted supernatant, the alfa peptide protected CRL 691 cells from inhibition when compared to the diluted supernatant alone. Electron microscopy of sensitive cells treated with lactocin 705 (alfa plus beta) showed that the cell wall of CRL 691 was severely damaged with mesosome-like membranous formations producing into the cytoplasm. A similar effect, although less pronounced, was also observed when the beta peptide, was added alone to the cell suspension. These data suggested the beta peptides were as effective in dissipating the transmembrane electrical potential suggesting that the presence of both peptides is necessary to inhibit CRL 691 cells