1966 Volume 31 Issue 1 Pages 80-88
1. RNA accumulated during the course of regeneration in both the macronucleus and cytoplasm of stentors. Levels were higher at eight hours near the end of regeneration than at four hours.
2. With both actinomycin D and 5-flurouracil, levels which inhibit RNA synthesis in mammalian cells were initially ineffective in suppressing regeneration in stentors, but after exposure for relatively long periods, levels of macronuclear and cytoplasmic RNA was reduced, and regeneration was inhibited.
3. Very high levels (15-25 γ/ml) of actinomycin D will inhibit regeneration in stentors if added before achievement of stage four, but if added at the sixth hour, regeneration is completed. The critical product emanating from the macronucleus prior to stage four is probably messenger RNA.
4. The results obtained with both actinomycin D and 5-flurouracil suggest that the high degree of polyploidy of the macronucleus protects the organism from the effects of antimetabolites which operate on genetic loci.
5. RNase at 0.5 mg/ml concentration prevented regeneration, and appeared to physiologically destroy RNA in the stentors, but organisms which had almost been depleted of RNA were able to regenerate after a very short lag period.