Figure 2. Influence of irradiation on plating efficiency. Untreated or treated cells were plated with 1,000 or 2,000 cells/well in 6-well plates, cultured for 5 to 11 d. Colonies greater 50 cells were counted, and plating efficiency was calculated as ratio of the number of colonies to the number of seeded cells × 100%. Three independent experiments, each in duplicate were performed. Upper panel: representative wells after staining. Lower panel: data after counting the cell clones. Symbols represent means ± SEM, (p ≤ 0.05, two-tailed), *, vs. 0 Gy; # vs. A2058-0 Gy; Mann-Whitney U test.