Buoyant density of native chromatin

Laser Raman spectra of calf thymus chromatin and its constituents

“…Finally, the DNA was separated from its histone complement by fractionation of either the core chromatin or the (H3.H4)/DNA complex in a 2.0 M NaCI-Tris buffer. The protein/DNA ratio in the isolated complexes was determined after each chromatographic separation from the ultraviolet (UV) spectrum of the collected samples (Raynauld and Ohlenbusch, 1972), to insure that the expected DNA/histone stoichiometry was in fact obtained.…”

The fractionation of active and inactive chromatins from erythroid cells of chicken

“…After Triton X-100 treatment, all of the chromatin banded above 1.340 with the main peak above 1.362. This is in the same range of density as calf thymus chromatin [5].…”

“…Triton-treated nuclei) was fractionated by centrifugation in sucrose:glucose gradients made as described by Raynaud and Ohlenbusch [5]. The chromatin suspensions in Triton-containing I.S.…”

“…However, these enrichments have not produced substantial amounts of cells still capable of cell division from which reasonably pure chromatin retaining transcriptional potential could be prepared for biochemical examination. We have succeeded in approaching this goal by taking the marrow of chickens recovering from phenylhydrazine-induced anaemia, preparing nuclei relatively free of cell membranes following the technique of Zentgraf et al [4], removing extranuclear membranes with non ionic detergents, and fractionating the unsheared chromatin by isopyenic centrifugation in density gradients of sucrose and glucose as described by Raynaud and Ohlenbusch [5].…”

Isopycnic Centrifugation of Chromatin in Renografin Solutions

“…Other experiments have tried to avoid the high salt concentrations by the use of nonionic solutes . Raynaud and Ohlenbusch (1972) have described the use of gradients of sucrose and glucose, and Hossainy, Zweidler, and Block (1973) have reported results with chloral hydrate gradi-7 8 0 ABSTRACT Solutions of Renografin (30-60%) can be centrifuged to form density gradients in the range from 1 .0 g/cm 3 to 1 .4 g/cm 3 , or, alternatively, preformed gradients can be made which under appropriate conditions of centrifugation have an indefinite stability . Such solutions have a low viscosity and a relatively low ionic strength .…”