A solution containing plasmid DNA, saturating amounts of ethidium bromide, and CsCl (44% w/v) is layered between two solutions of lesser (35% w/v CsCl) and greater density (59% w/v CsCl). During centrifugation to equilibrium, the closed circular plasmid DNA and linear DNAs form bands at different densities. - [Read Purification of Closed Circular DNA by Equilibrium Centrifugation in CsCl-Ethidium Bromide Gradient]
Solutions containing plasmid DNA are adjusted to a density of 1.55 g/ml with solid CsCl. The intercalating dye, ethidium bromide, which binds differentially to closed circular and linear DNAs, is then added to a concentration of 200 mu;g/ml. During centrifugation to equilibrium, the closed circular DNA and linear DNAs form bands at different densities. - [Read Purification of Closed Circular DNA by Equilibrium Centrifugation in CsCl-Ethidium Bromide Gradients]
The liver of a rat is cannulated and perfused in situ with buffer, following which it is excised and perfused in a closed system with a collagenase solution. After a period of time the liver begins to break up, at which point it is transferred to a measuring cylinder and culture medium is added. It is then gently agitated to cause the release of cells which are subsequently filtered and allowed to settle out. The parenchymal and non-parenchymal cells form two distinct layers which can be separat - [Read The Isolation and Culture of Rat Hepatic Cells Protocol]