摘要：It was found that lactococcin R adsorbed to all gram-positive but not to the gram-negative bacteria tested and its adsorption was dependent on pH. It was observed that the binding of lactococcin R was prevented by anions of several salts (CI-, PO4-3) and lipoteichoic acid. It was determined that pretreatments of sensitive cells and cell walls with detergents, organic solvents or enzymes did not reduce subsequent binding of lactococcin R. However, treatment of cell wall preparations with methanol: chloroform and hot 20% TCA caused such walls to lose their ability to adsorb lactococcin R. It was found sensitive cells treated with lactococcin R lost high amounts of intracellular K+ ions, UV-absorbing materials and became more permeable to ONPG. In addition, it was observed that different lactococcin R concentrations (0-2560 AU/ml) decreased the colony counts of Listeria monocytogenes by 99% and also caused a reduction in the absorbance values of L. monocytogenes . This results show that the mode of action of lactococcin R is bactericidal rather than bacteriostatic.
