when plasma membranes were prepared from cells which had been incubated for 18 h in the presence of 0.5 muci/ml [ 3h ] thymidine such that greater than 10 ( 9 ) acid insoluble counts could be demonstrated in the whole cell homogenates , no [ 3h ] thymidine label and presumably , therefore , no dna , could be shown to be coincident with either the 1.10 or 1.17 density .
C0007603
plasma membranes
C0007634
cells