Further studies on the maintenance of mate-killer (mu) particles in Stock 540Paramecium aurelia

Abstract

SUMMARY1. Mu particles can be removed from stock 540Paramecium aureliaby incubation in a solution of 1·0 mg/ml RNAase for 12 h. Only a relatively small percentage of cells become mu-free and it is suggested that this variation is due to the activity of the M genes producing metagons at different times.2. Paramecia, made mu-free by growth at elevated temperatures, can be re-infected with mu by allowing the cells to swim in a brei of stock 540 paramecia. The re-infection is only permanently successful with cells that were made mu-free 10 days earlier.