title: Inhibition of enterocin CRL35 antibiotic activity by mono- and divalent ions.
abstract: OBJECTIVE
  The aim of this work was to study the influence of different cations on the enterocin CRL35 activity.
  
  
  RESULTS
  The antilisterial activity of enterocin CRL35 was tested by performing viability curves and measuring the dissipation of the proton motive force by fluorescent methods upon the addition of Ca2+, Mg2+, Li+, K+ and Na+ chlorides. The peptide uptake by sensitive cells was studied in the different conditions as well. The addition of calcium and magnesium chlorides (0.5-2 mmol l(-1)) induced an inhibition of the peptide activity. Potassium, sodium and lithium chlorides have an inhibitory effect as well, but at different range of concentration compared with divalent cations (50-150 mmol l(-1)). Interestingly, we found a differential protection effect among monovalent ions, KCl being almost nonprotective, meanwhile LiCl shows the stronger effect and NaCl has an intermediate effect. The ion effect depends on the pH, being more efficient in acidic media. Both mono and divalent ions inhibited the ability of the peptide to dissipate the transmembrane electric potential and pH gradient. Furthermore, the peptide uptake was also inhibited.
  
  
  CONCLUSIONS
  The enterocin CRL35 activity is strongly dependent on the pH and the nature of the salts present in the medium.
  
  
  CONCLUSIONS
  These findings will allow definition of the best system in which this peptide can be applied as biopreservative.
authors: Departamento de Bioquímica de la Nutrición, Instituto Superior de Investigaciones Biológicas, Instituto de Química Biológica Dr Bernabé Bloj, San Miguel de Tucumán, Argentina.
authors: C J
authors: CJ
authors: Minahk
authors: R D
authors: RD
authors: Morero
mesh_terms: D001430:Bacteriocins / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D002413:Cations, Divalent / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D008087:Listeria / Q000187:drug effects* / Q000378:metabolism; D008274:Magnesium / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D011188:Potassium / Q000494:pharmacology; D012964:Sodium / Q000494:pharmacology
chemical_list: D001430:Bacteriocins; D002413:Cations, Divalent; C121783:enterocin CRL35; D012964:Sodium; D008274:Magnesium; D011188:Potassium; D002118:Calcium