Decreased DNA damage by acid and increased repair of acid-damaged DNA in acid-habituated Escherichia coli.

A study of the conjugal transfer of ColV,I-K94 tn 10 from acid-treated donors suggested that acid-habituated recipients repair acid-damaged plasmid DNA better than those that are not habituated. The presence of an increased repair activity for acid-damaged DNA in habituated cells was confirmed by isolating pBR322 from acid-treated organisms; habituated cells produced more transformants when transformed by it than did non-habituated ones. Additionally, agarose gel electrophoretic studies of pBR322 DNA isolated from acid-damaged cells and tests of its transforming activity both indicated that plasmid DNA in habituated cells is less damaged by extreme acidity than is that in non-habituated organisms.