FIG. 4.

Survival of E. coli recA mutant strain Top10F′ containing cloned recA genes grown in the presence of different concentrations of MMS. The number of colonies on the plates without MMS was defined as 100% survival, and the mean percentages of survival and 95% confidence intervals were determined by using 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.