ON THE MODE OF ACTION OF A NEW ANTIFUNGAL ANTIBIOTIC, PYRROLNITRIN

Abstract

Pyrrolnitrin inhibits the syntheses of protein, RNA and DNA to almost the same degree. It also inhibits respiration but this site does not seem to be the primary action. It does not inhibit the biosynthesis of porphyrin. It is not an uncoupler of oxidative phosphorylation. It inhibits the transport of many substances, and causes the leakage of A_260mμ absorbing materials inside the cells. Pyrrolnitrin bursts the protoplasts of Bacillus megaterium KM strain at the growth inhibitory concentration. This action is completely neutralized by an approximately equimolar concentration of some phospholipids in the cell membrane components. It is concluded that the primary damage by pyrrolnitrin occurs in the cell membrane through a combination of pyrrolnitrin and some phospholipids.