The free-living, ciliated protist Tetrahymena, which can be grown in synchronized cultures, lends itself to studies of protein synthesis and organelle morphogenesis in eukaryotic cells . The isolation of polyribosomes, the sites of protein synthesis, from Tetrahymena was reported by Whitson et al . (5) . After lysis of the cells by indole-saturated buffer, the polysomes were isolated in 0 .01 M Tris buffer, pH 7.5 containing 0 .5 trial MgC1 2 . These investigators presented evidence for the presence of dimers to pentamers, and for changes in the polysome profile during various phases of the cell cycle . However, the yields of polysomes were low,