Bacterial membrane injuries induced by lactacin F and nisin.
The combined action of nisin and lactacin F, two bacteriocins produced by lactic acid bacteria, is additive. In this report, the basis of this effect is examined. Channels formed by lactacin F were studied by experiments using planar lipid bilayers, and bactericidal effects were analyzed by flow cytometry. Lactacin F produced pores with a conductance of 1 ns in black lipid bilayers in 1 mM KCI at 10 mV at 20 degrees C. Pore formation was strongly dependent on voltage. Although lactacin F formed pores at very low potential (10 mV), the dependence was exponential above 40 mV. The injuries induced by nisin and lactacin F in the membranes of Lactobacillus helveticus produced different flow cytometric profiles. Probably, when both bacteriocins are present, each acts separately; their cooperation may be due to an increase in the number of single membrane injuries.
Biomedical Research Center of Bellvitge, University of Barcelona, Spain.
M
M
Dalmau
Elke
E
Maier
Natalia
N
Mulet
Miguel
M
Viñas
Roland
R
Benz
D001430:Bacteriocins / Q000302:isolation & purification / Q000494:pharmacology*; D002462:Cell Membrane / Q000187:drug effects* / Q000378:metabolism; D005434:Flow Cytometry; D007778:Lactobacillus / Q000187:drug effects* / Q000502:physiology; D008051:Lipid Bilayers / Q000378:metabolism; D008564:Membrane Potentials / Q000187:drug effects; D009561:Nisin / Q000494:pharmacology*
D001430:Bacteriocins; D008051:Lipid Bilayers; C067573:lactacin F; D009561:Nisin