METHODS TO DEMONSTRATE THE BACTERICIDAL ACTIVITY OF BACTERIOCINS

Two simple techniques were developed to demonstrate bactericidal activ ity of bacteriocins. Both were based on allowing a lawn of indicator s train to grow first, then exposing the lawn to bacteriocin-containing cell-free supernatants in a well cut in the seeded agar lawn or by ino culating the bacteriocin-producing strain onto the indicator lawn. Lys is of cells of the indicator strain resulted in a clear zone. These te chniques may be adapted to test antimicrobial substances other than ba cteriocins and to help to determine their modes of action.