"Bioassay and MICs of filipin III and its intermediates. Bioassays were performed with ethyl acetate-extracted culture broths from early stationary phase-grown cells. C. utilis was used as test organism. MICs of the purified filipin derivatives for C. utilis and S. cerevisiae were measured by broth microdilution assay (see "" Methods ""). Abbreviations are as in Fig. 4 ."