Fractionation of rat liver nuclei by sucrose gradient centrifugation

Separation of Nuclei Representing Different Phases of the Growth Cycle From Unsynchronized Mammalian Cell Cultures

“…Nuclei isolated from rat liver homogenates have been fractionated previously by unit gravity sedimentation (17) and by low-speed centrifugation (18) in the presence of stabilizing density gradients . The fractionation appeared primarily to resolve the nuclei of different cell types (17), namely stromal and hepatic parenchymal nuclei, although there was also some resolution of diploid and tetraploid (17,18) parenchymal nuclei .…”

Ploidy and biochemical characteristics of liver cell nuclei in rats fed different amounts of dietary protein

“…Quantitatively, diploid parenchymal nuclei of the rat contain approximately 7 pg DNA (Falzone.. Barrows, and Yiengst 1952). (Falzone, Barrows, and Yiengst 1962;Albrecht 1968, Johnston et al, 1968a and the relative distribution within each class assessed. The latter method has not been utilized to quantitate growth-associated tetraploidization or relative changes in protein deficiency.…”

“…For the studies described as experiment II, single degree of freedom orthogonal compari sons and minimum differences required for statistical signi ficance (P< 0.01) were computed,H. Sucrose Gradient Sedimentation AnalysesNuclei were separated into diploid and, tetrapioid classes using the principle of velocity of sedimentation at unit gravity(Falzone, Barrows, and Yiengst 1962) and employing low speed centrifugation to permit more rapid separations(Albrecht 1968). Aliquots (2.0 ml) of nuclear suspensions were layered onto 49.5 ml linear sucrose gradients (15 to40% w/v in TKM) in cellulose nitrate tubes (prepared at room temperature and equilibrated overnight at 4 C).…”

Ploidy and biochemical characteristics of liver cell nuclei in rats fed different amounts of dietary protein

“…Classical chemical estimates require enumeration of nuclei either in whole homogenates or in isolated nuclear preparations and the chemical determina tion of DNA to obtain data in absolute amounts of DNA per nucleus. Finally, nuclei of diploid and tetraploid classes may be separated on the basis of their velocity of sedi mentation (Falzone, Barrows, and Yiengst 1962;Albrecht 1968, Johnston et al, 1968a and the relative distribution within each class assessed. The latter method has not been utilized to quantitate growth-associated tetraploidization or relative changes in protein deficiency.…”

“…Nuclei were separated into diploid and, tetrapioid classes using the principle of velocity of sedimentation at unit gravity (Falzone, Barrows, and Yiengst 1962) and employing low speed centrifugation to permit more rapid separations (Albrecht 1968). Aliquots (2.0 ml) of nuclear suspensions were layered onto 49.5 ml linear sucrose gradients (15 to When studies in this laboratory were performed using 15 to 40% w/v linear sucrose gradients combined with low speed centrifugation, separations could be effected in 10 minutes, and discrete bands corresponding to two major sedi mentation classes of hepatic nuclei were grossly visible.…”