ehrlich ascites cells , in which replication units at the beginning of the s phase started and grew synchronously , were obtained by the following protocol : ( 1 ) selection of g1 cells by zonal centrifugation , ( 2 ) hypoxia for 12 h , ( 3 ) reaeration , ( 4 ) addition of cycloheximide ( 30 microm ) within the first minute after reoxygenation .
C0242961
replication
C0007634
cells