In vitro activity: The antibiotic puromycin is produced by the actinoniycete, Streptornyces alboniger, and has been used as a tool for studying protein synthesis in a number of systems. Puromycin can be used for the selection of recombinant cells from noncultured cells.

Cell Assay: When treated with puromycin dihydrochloride at different concentrations, the growth rates of T. thermophila changed. In the first 24 h, puromycin dihydrochloride at a concentration of 50 μg/ml reduced the growth rate by 80%, but did not completely block the cell growth; until 72 h, there was a gradual cell number increase. At 100 μg/ml, puromycin dihydrochloride completely blocked the cell growth; in the first 48 h under this condition, almost all of the cells died, surviving cells grew rapidly after 48 h. Puromycin dihydrochloride at 150 μg/ml completely inhibited the cell growth for 72 h. By 72 h, the majority of cells died, and then surviving cells grew. Puromycin dihydrochloride at 200 μg/ml made almost all the cells die by 48 h, and hence no survivors appeared.