fractionation by precipitation with 1 m nacl , followed by chromatography on cellulose columns , and by rate zonal centrifugation in sucrose density gradients of labeled rna isolated from actinomycin d-treated and infected baby hamster kidney cells revealed the presence of the following virus-specific types of rna : ( i ) single-stranded rna with a heterogeneous sedimentation pattern , the 38s viral rna becoming the predominant species only after long periods of labeling late after infection ;
C0010934
actinomycin d
C0021270
baby