FIG. 5.

Purification of recoated particles by isopycnic density centrifugation. (A) Particle distribution. The solid line shows the fluorescence of each fraction of a CsCl density gradient after mixing with ethidium bromide and illuminating at 302 nm. Black circles indicate density. The peak of fluorescence, which identifies RNA-containing particles, is at 1.36 g/ml. Fractions were combined into pools a to h. (B) Infectivity of each pool from panel A.