Table 1 DNA sequence changes in spontaneous, MO34-, and 6-HAP–induced d-cycloserine–resistant cycA mutants.

Mutation typeSpontaneous
No. (%)
MO34 (1 μg/ml)
No. (%)
6-HAP (4 ng/ml)
No. (%)
Transitions7 (11%)64 (97%)*65 (99%)*
G·C→A·T5 (7.9%)19 (29%)34 (52%)
A·T→G·C2 (3.2%)45 (68%)31 (47%)
Transversions7 (11%)00
G·C→T·A3 (4.8%)00
G·C→C·G1 (1.6%)00
A·T→C·G3 (4.8%)00
Deletions 1 nt9 (14%)01 (1%)
Deletions >1 nt15 (24%)2 (3%)0
Duplications9 (14%)00
IS elements16 (25%)00
Total mutations6366**66**

*Significantly different from the spontaneous value (Fisher’s exact test, P < 10−4).

**Two Cycr clones contained two mutations in the cycA gene.