“…)Actinomycin D inhibited the incorporation of 14 C from [ 14 C]-formate, [1- 14 C]-glycine, […, [8- 14 C]guanine, [2- 14 C]2,6-diaminopurine, and [6- 14 C]orotic acid into RNA more than into DNA, and in a … was inhibited more than the incorporation into adenine.”