Effect of cyclic imide and the RNA synthesis inhibitor actinomycin (act.) D on the expression of half-amidase and imidase. The experimental conditions (sets A through D) are described in Materials and Methods. Symbols: set A (glutarimide addition without actinomycin D), ■ (half-amidase activity), ┌ (imidase activity), and ⧫ (cell growth); set B (glutarimide addition with actinomycin D), ● (half-amidase activity), (imidase activity), and ▴ (cell growth); set C (sucrose addition without actinomycin D), □ (half-amidase activity), ⊞ (imidase activity), and ◊ (cell growth); set D (sucrose addition with actinomycin D), ○ (half-amidase activity), ⊕ (imidase activity), and ▵ (cell growth). Addition of glutarimide or sucrose without or with actinomycin D is indicated by a thick arrow. The values of half-amidase activity, imidase activity, and optical density (OD) are the averages of three separate determinations that were reproducible within ±5%.