Figure 3
Complementation assay in the E. coli DNA repair deficient strains.
(A) Survival curve of the recA- strain subjected to increasing concentrations of H2O2 (0–2 mM) for 30 min. recA- strain transformed with empty vector (•) and with pTrc-ExoMeg1 (▲).Values are the mean ± SD of three independent experiments in duplicate. Statistical analysis by two-way ANOVA and Bonferroni post-test, *P < 0.05, **P < 0.01 and ***P < 0.001. (B) Complementation assay in the E. coli xthA-nfo- strain. A survival increase in plates with MMS or H2O2 was observed in the presence of pTrc-ExoMeg1 in the E. coli double mutant strain. The cultures were induced by 0.1 mM IPTG. Undiluted cultures and serial dilutions (10−1, 10−2, 10−3 and 10−4) from cultures (OD600 of 0.8) were plated on LB agar containing different concentrations of MMS or H2O2. AB1157 was used as wild type (WT) strain proficient in DNA repair.
