Effect of nalidixic acid on the growth of deoxyribonucleic acid bacteriophages

The effect of nalidixic acid on the growth of various deoxyribonucleic acid (DNA) bacteriophages has been investigated by one-step growth experiments. The Escherichia coli bacteriophages T5, lambda, T7 and phiR are strongly inhibited by nalidixic acid, whereas T4 and T2 are only partially inhibited. The Bacillus subtilis bacteriophages SP82, SP50, and phi29 are relatively unaffected by nalidixic acid. There is no correlation between those bacteriophages which can grow in the presence of nalidixic acid and the presence of an unusual base in the phage DNA.