The Growth in vitro of Killer Particles from Paramecium aurelia and the Axenic Culture of this Protozoon

摘要

Summary: Paramecia belonging to certain strains of Paramecium aurelia (syngens 1, 2 and 8) were transferred from dual culture with bacteria to axenic media, where the growth of some stocks continued, with weekly subculturing. The only axenically grown stock found to be capable of supporting growth of mu particles indefinitely was stock 138 (syngen 8).Lambda and mu particles from axenically grown Paramecium aurelia were cultivated in vitro in a highly complex medium at 27° under aerobic conditions. The particles retained their characteristic killing action on certain P. aurelia stocks but could not infect sensitive paramecia. The particles divided at approximately one fission per day and achieved a maximum density of only 16-20 x 103/ml. The implications of these studies for the interaction of the nuclear genes and the killer particles are discussed.