Partial characterization of Yersinia intermedia bacteriocin

Yersinia intermedia produces a temperature-dependent (25°C) bactericidal substance that is active against other Yersinia species. Crude preparations of the inhibitory substance were inactivated by chymotrypsin, trypsin, pronase, and heating but were not affected by lipolytic enzymes, chloroform, or other organic solvents. These data suggest that the active molecule is a bacteriocin of a proteinaceous nature. The molecular weight of the bacteriocin was estimated to be >14,000. Exposure of agar fragments containing the active component to a pH range of 3 to 11 did not affect bactericidal activity. Bactericidal activity against the Y. frederiksenii indicator strain was shown by simultaneous and deferred antagonism and by the associative culture technique. The liquor from cell-free macerated agar fragments and broth cultures, however, were devoid of antibacterial activity.