Table 1.

LD₁₀₀ values for E. coli KY895 exposed to AZT

KY895 transformed with	LD100 for AZT (μM)
pGEX-2T	>100
toTK1	0.0316
HSV-tk	1.000

toTK1 or HSV-tk was subcloned into pGEX-2T, and the TK-deficient E. coli strain KY895 was transformed with the resulting plasmids or the empty vector. Growth of colonies was tested with logarithmic dilutions of AZT. The values are the average from 2 to 4 independent experiments.