Abstract
A screening method for the antibiotics capable of inhibiting synthesis of nucleic acid in bacterial cells or mammalian tumor cells was investigated. The DNA and RNA syn-theses in Bacillus subtilis 168 thymine-, indole- were studied by the assay of incorporations of 3H-thymine and 14C-uracil into the cells, respectively. With known antibiotics against nucleic acid synthesis, the adequacy of the method was examined, and the result proved that this method is more sensitive and specific than the conventional assay methods.
It was found as a new fact that cellocidin is a potent and specific inhibitor to the thymine incorporation into DNA.
By an almost similar procedure, an inhibitory effect of several antibiotics on the incorporations of 3H-thymidine and 14C-uridine into Ehrlich ascites carcinoma cells was also studied.
