FIG. 7.

Effect of IPTG on virus yields. (A) Effect of IPTG concentration on 24-h yields. BS-C-1 cells were infected with WR (⧫), vG4L/G4Li (■), or vG4Li (▴) at a multiplicity of 5 and incubated with medium containing 0 to 250 μM IPTG for 24 h. Virus yields were determined by plaque assay in the presence of 50 μM IPTG for all viruses. (B to D) Time course of virus production in the presence (filled symbols) or absence (unfilled symbols) of 50 μM IPTG. The virus was WR (B), vG4L/G4Li (C), or vG4Li (D). Virus titers were determined by plaque assay as described for panel A.