Protoplasts from Listeria monocytogenes 7 resistant mutant cannot interact with enterocin CRL35

MASIAS E; DUPUY FG; MINAHK CJ; BELLOMIO A; CILLI E; ACUÑA L

Rosario

Congreso; SAIB L Reunión Anual; 2014

SAIB

Enterocin CRL35 is a pediocin-like bacteriocin produced by Enterococcus mundtii CRL35. It is active against thefood-borne pathogen Listeria monocytogenes. To further study its mechanism of action, two resistant Listeriavariants were isolated from sensitive cells. Once confirmed the identity of the mutant strains by rep-PCR and 16Sribosomal RNA gene sequencing, its phenotype was compared with the sensitive parental strain, Listeriamonocytogenes 7. The growth of the resistant mutants was slower as compared to the parental strain with lowerglucose consumption and a lower medium acidification, showing differences in their metabolisms. On the other hand,even though enterocin CRL35 was able to bind to both sensitive and resistant cells with similar affinity, it was unableto interact with the protoplasts of one of the resistant mutant, as it was revealed by fluorescence polarization. The lackof membrane association in protoplasts strongly suggests that major changes in the plasma membrane of that mutantmay take place. Therefore, a complete analysis of the membrane was carried out in order to fully describe theenterocin interaction. The present work shows novel information about the enterocin CRL35 requirements formembrane binding, which is believed to be the key step in the mechanism of action.