The action of ribonuclease and 8-azaguanine on mate-killer paramecia

Abstract

1. Mate-killer paramecia (derived from stock 540, P. aurelia) were treated with ribonuclease and 8-azaguanine to determine the effect of these two substances on the mu particles and metagons.2. Ribonuclease destroyed the metagons in living paramecia but had no direct effect on the viability of the mu particles. The latter were however destroyed precisely after one fission of cells whose metagons had been eliminated by ribonuclease treatment.3. Re-synthesis of metagons was found to take place between the second and third fissions after treatment with ribonuclease, if the dominant gene M2 was present.4. Increasing the concentration of ribonuclease in the external medium, or in the duration of exposure of paramecia to ribonuclease, resulted in destruction of increasing proportions of metagons.5. 8-azaguanine did not destroy metagons already present, but destroyed the mu particles immediately.6. It is concluded that the results obtained with these two substances are consistent with the view that RNA is an essential constituent of metagons.