Mitomycin C treatment results in amplification of RD2. A Rapid decrease in O.D. of a liquid culture of strain MGAS6180 after mitomycin C addition. The decreased O.D. is likely due to prophage induction followed by lytic cycle phage release. Smaller drop in OD is observed after treatment with hydrogen peroxide. B. The RD2 element is present in 6-9 copies per chromosome in the absence of inducer. C. The RD2 element is not induced by oxidative stress. Bars in each group represent the RD2 copy number after 1 h, 2 h, 3 h, and 16 h after treatment with hydrogen peroxide. D. RD2 is induced by DNA damage. Bars in each group represent the increase in copy number at 1 h, 2 h, 3 h, and 16 h after treatment with mitomycin C. The statistical significance of the increase in RD2 copy number was determined by t-test, *** on the graph denotes p value below 0.001.