Abstract 1384 Manganese deficient strains of E. coli exhibit elevated rates of mutation

The role of the divalent manganese ion, Mn2+ in helping organisms survive hydrogen peroxide (H2O2) stress, was investigated by studying mutation rates in E. coli. Mn2+ is imported by the proton-coupled metal transport pump MntH in E. coli and several other species of bacteria, and although it is not necessary for normal growth in E. coli, it is crucial for survival in the face of hydrogen peroxide threat. Here, Lambda Red recombination was used to knock out mntH in reporter strains of E. coli. The knockout strains are deficient in their ability to import manganese as measured by atomic absorption spectroscopy (AAS). Under a Lac-reversion assay, mnth knockout strains exhibit lower rates of reversion than the parent strains. This effect is attenuated under anaerobic growth conditions and is absent in a reporter strain for non-oxidative DNA mutation events. This suggests a role for manganese in mechanisms that maintain genomic integrity in the face of oxidative stress. This work was possible with the generous support of a Mount Saint Mary's University Professional Development Grant, the W.M. Keck Foundation, NSF S-STEM Grant 1564677, NSF HSI Grant 1832472, a Department of Education Title III Grant, the StaufferFoundation, and the EastonFoundation.