title: Hydrogen ion dependent reversible fibrillarization and hydration of chromatin in divalent cation-depleted isolated rat liver nuclei.
abstract: Rat liver cell nuclei isolated in the presence of Ca++ and Mg++ ions were exposed to citrate buffer at different pH levels. Their morphology was studied with the electron microscope and the water content measured. At a low pH the chromatin remained compact, but at neutral pH an intense fibrillarization of the chromatin was observed; and, seemed to be reversible, because of deoxyribonucleoproteins (DNP) filaments which dispersed at a pH of 7 were repacked to their previous site at a pH of 3. The ribonucleo-proteins (RNP)-containing structures did not show the same reversible fibrillarization. In addition to the morphological changes, a large increase in the water content ("water-holding capacity") of the chromatin structures was observed.
mesh_terms: D000818:Animals; D002458:Cell Fractionation / Q000379:methods; D002467:Cell Nucleus / Q000648:ultrastructure*; D002843:Chromatin / Q000648:ultrastructure; D006863:Hydrogen-Ion Concentration; D008099:Liver / Q000648:ultrastructure*; D008297:Male; D008854:Microscopy, Electron / Q000379:methods; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D002843:Chromatin