ANTAGONISM OF THE D-ALANINE REVERSAL OF D-CYCLOSERINE ACTION BY L-ALANINE IN MYCOBACTERIUM ACAPULCENSIS.

Abstract

Summary Growth of Mycobacterium acapulcensis is inhibited by D-cycloserine. This effect is completely reversed by equimolecular concentrations of D-alanine. L-alanine is totally inactive while DL-alanine is only effective at higher concentrations. L-alanine antagonized the protection afforded by D-alanine, a fact that cannot be explained by a simple competition between these diastereoisomers at the cell membrane level. In the presence of D-cycloserine a mucopeptide accumulates in the sensitive strain and also in the resistant mutant when allowed to grow at high antibiotic concentrations.