Ethidium bromide CsCl density gradient

Fig. 6.1. (a) CsCl density gradient centrifugation separates DNA from RNA and proteins due to their different buoyant densities, (b) By addition of ethidium bromide, chromosomal DNA can be separated from plasmid DNA. 

The DNA can he seen directly in the CsCl gradient by reversibly staining with ethidium bromide (Firtel and Bonner 1971). Solid CsCl is added to the DNA solution to make the density up to about 1.55 g ml (0.97 g CsCl to each 1 ml original DNA solution) followed hy 1/20 volume of ethidium bromide solution (10 mg/ml in water). Spinning time is 48 hr at 40,000 rev/min. RNA and... 

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