Chloramphenicol and chromosomal morphology

Eight-hundred mcg of chloramphenicol (CM) was added to 10 ml of normal phytohemagglutinin-stimulated leukocyte cultures at various stages of cell cycle. The diluent used to dissolve CM was added to the control cultures. The cultures were terminated for chromsomal analyses. More abnormalities were seen in the CM added cultures. The highest incidence was seen when CM was added at G0 and the lowest, at G2. These parallel well with the acidic residual chromosomal protein fraction in HeLa S-3 cells. It was concluded that CM is capable of inhibiting protein synthesis resulting in chromosomal protein deficiency. This deficiency produces "weakness" in the chromosomal backbone.