FIG 3.
The effect of milbemycin oxime on TruMDR1, TruMDR2, TruMDR3, and TruMDR5. A total of 106 cells of S. cerevisiae transformants were seeded to make a lawn on MMG plates with a sub-MIC of ITC (0.5 μg/ml) or VRC (0.64 μg/ml) incorporated into the medium. Nonimpregnated cellulose disks, 6 mm in diameter, were then placed at the surface of the medium and individually saturated with 5 μg of milbemycin oxime. The plates were incubated at 30°C, and growth inhibition was observed after 5 days. Growth inhibition was recorded for TruMDR3. No effect was observed for TruMDR1, TruMDR2, and TruMDR5, or for TruMFS1 and TruMFS2 (not shown). Milbemycin oxime has only been tested when the transporter induced resistance to VRC or ITC.