Studies on nuclei of Paramecium aurelia. I. Isolation and purification by continuous or discontinuous sucrose gradient centrifugation and biochemical composition.

Abstract

SYNOPSIS. Nuclei of Paramecium aurelia were isolated and purified by a new method involving the use of continuous or discontinuous sucrose gradient centrifugation. As judged from the DNA levels or nuclear counts in the purified samples, 21–22% of the nuclei were recovered by this method. The single density of the nuclei estimated on the basis of linear sucrose gradients was between 1.35 ± 0.01 and 1.36 ± 0.01. The average picogram quantities of total protein, DNA, and RNA per nucleus were 435, 62.2, and 51.2, respectively.