FIG. 3.

Survival after exposure to UV light of recA mutant E. coli strain Top10F′ containing cloned recA genes. The doses of UV light (254 nm) delivered to the bacteria on plates are indicated. The number of colonies on the untreated control plate was defined as 100% survival, and the mean percentages of survival on treated plates were determined by comparison of colony counts with the control colony counts. The error bars indicate the 95% confidence interval at each dose based on three to six replicates. Data for cells with plasmids containing E. coli recA (pEc:recA), L. biflexa recA (pLb:recA), B. burgdorferi recA (pBb:recA), and B. hermsii recA (pBh:recA), as well as an empty vector control (pBluescript), are shown.