THE EFFECTS OF MAGAININ-2, CECROPIN, MASTOPARAN AND MELITTIN ON BRUCELLA-ABORTUS

The effect of the alpha-helical polycationic peptides magainin 2, meli ttin, mastoparan and cecropin on the viability of Brucella abortus 544 (type species), B. abortus S19 (vaccine strain) and B. abortus S2308 (vaccine challenge strain) was determined. Rough mutants of these stra ins and the rough candidate vaccine strain B. abortus RB51 were also t ested. S. typhimurium was used as a control. The peptides did not affe ct the viability of B. abortus smooth strains but some of the peptides affected viability of the rough strains. Magainin 2 at a concentratio n of 100 mu g ml(-1) did not reduce the viability of the rough B. abor tus strains. Cecropin at a concentration of 15 mu g ml(-1) reduced the viability of the rough strains by approximately 10-fold. Mastoparan a t a concentration of 50 mu g ml(-1) reduced the viability of the rough strains by approximately 100-fold. Melittin at a concentration of 20 mu g ml(-1) reduced the viability of the rough strains of B. abortus b y approximately 1000-fold. The brucellae were significantly more resis tant to all the cationic peptides than was S. typhimurium.