Antimicrobial Activities and Antagonists of Bacilysin and Anticapsin

Abstract

The dipeptide antibiotic bacilysin is active against a wide range of bacteria and against Candida albicans. Its C-terminal amino acid, anticapsin, is a very poor antibacterial agent. The activities of both substances are strongly dependent on the nature of the culture medium. In a minimal medium the minimum inhibitory concentration for bacilysin with Escherichia coli B is 10-3 .mu.g ml-1. The action of bacilysin is antagonized by a variety of dipeptides and that of anticapsin by a number of amino acids. With several bacteria, bacilysin-resistant mutants are found in unusually large numbers. Peptide and amino acid transport systems may play a role in these phenomena. The antimicrobial action of bacilysin is also inhibited by glucosamine and N-acetylglucosamine. This antibiotic may interfere with glucosamine synthesis and with the synthesis of microbial cell walls.