The mycoplasmacidal effect of herbicolin A.

This study was to determine if the inhibitory effect of herbicolin A to sterol-requiring members of the class Mollicutes is due to a mycoplasmastatic or a mycoplasmacidal effect. Two strains were used as test organisms, Mycoplasma capricolum (California kid) and Ureaplasma urealyticum (T-960). Following exposure of the mycoplasmas to various inhibitory concentrations of herbicolin A for various periods of time, elimination of the antibiotic as a preliminary to demonstration of any surviving organisms was endeavoured by three different procedures: (a) serial dilution, (b) filtration through a membrane filter, and (c) separation of the organisms by centrifugation. The results of these experiments showed a mycoplasmacidal effect of herbicolin A.