Journal of Cell Science, Vol 9, 719-726, Copyright © 1971 by Company of Biologists

Submitted on March 29, 1971

DNA from Isolated Pellicles of Tetrahymena

¹ Department of Biochemistry, University of Hull Hull HU6 7RX, U.K.

Large pellicle fragments were isolated from Tetrahymena pyriformis, strain T, by 2 procedures: homogenization after treatment with 40% ethanol at -20 °C, or direct homogenization in a sucrose-EDTA buffer. All preparations contained entrapped mitochondria. DNA prepared from these pellicles was analysed on a CsCl gradient, and contained 3 components of buoyant densities 1.685, 1.688, and 1.698 g cm^-3 in variable proportions. The component at 1.685 g cm^-3 is similar in density to mitochondrial DNA and those at 1.688 and 1.698g cm^-3 to components of nuclear DNA. Most pellicle preparations contained a higher proportion of the heavy component (1.698 g cm^-3) than does nuclear DNA. A similar enrichment of this component could be demonstrated in high-speed pellets from fragmented nuclei. No unique pellicle-associated component could be demonstrated. No DNA could be isolated from very pure preparations of oral plates and we conclude that there is no evidence for the presence of a specific DNA associated with the pellicle.