Ion permeability induced by bacteriocins of Lactobacillus acidophilus M247 on artificial lipid membranes

Bacteriocins produced by lactic acid bacteria are known to induce ion permeability on the cytoplasmic membranes of several competing bacteria. The activity of a bacteriocin produced by Lactobacillus acidophilus M247 was studied on artificial lipid membranes made using the technique of Montal–Mueller. Bacteriocin was added to the KCl solution bathing one side of black lipid membrane (BLM). By applying external voltages of different polarity, increases in the membrane conductance were observed and channels with elementary conductance of about 68–70 pS were detected. The log–log plot of macroscopic conductance versus bacteriocin concentration was linear with a slope of 1 for the purest samples, indicating that one molecule of active bacteriocin is involved in the channel formation.