Mode of action of plantaricin L-1, an antilisteria bacteriocin produced by Lactobacillus plantarum

Abstract:

Plantaricin L-1, an anti-Listeria bacteriocin, was produced by Lactobacillus plantarum and successfully purified by SP-Sepharose FF cation exchange chromatography. The mechanism on energized cells of Listeria monocytogenes was studied with purified plantaricin L-1. After adding plantaricin L-1 to Listeria monocytogenes at 64AU/mL, leakage of intercellular K⁺ ions, inorganic phosphate, lactic dehydrogenase, UV-absorbing materials and the intracellular ATP was observed, and the action resulted in the dissipation of the membrane potential (△ψ) and pH gradient (△pH), two components of the proton motive force (PMF). All the data suggested that the primary site of action of plantaricin L-1 was the cytoplasmic membrane of sensitive cells. By forming the nonselective pores which leak ions and small organic compounds plantaricin L-1 induced the cells death, this action was similar to membrane corruption caused by peptide effect. Penetrability increased due to the enlarged pore and dysfuction of membrane transporters, which ensured efficient killing of target bacteria.