FIG. 1.
Inhibition of vaccinia virus by distamycin. (A) Effect of distamycin on vaccinia virus plaque formation. Monolayers of BSC40 cells were infected with 60 PFU of vaccinia virus for 48 h in the presence of the indicated concentrations of distamycin A (Sigma). Plaques were visualized by staining with crystal violet. (B) Effect of distamycin on virus yield in a single-step infection. BSC40 cells were infected with 10 PFU of vaccinia virus per cell for 24 h in the presence of the indicated concentrations of distamycin A. Cells were harvested and lysed, and virus yield was quantitated by plaque assay in the absence of the drug.