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Mutagenesis in Escherichia coli lacking catalase
Author(s) -
Abril Nieves,
Pueyo Carmen
Publication year - 1990
Publication title -
environmental and molecular mutagenesis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1
H-Index - 87
eISSN - 1098-2280
pISSN - 0893-6692
DOI - 10.1002/em.2850150403
Subject(s) - catalase , mutagenesis , escherichia coli , mutant , hydrogen peroxide , biology , mutation , bacteria , strain (injury) , mutagen , gene , microbiology and biotechnology , biochemistry , enzyme , genetics , dna , anatomy
Escherichia coli K‐12 strains completely lacking catalase activity due to mutations in katG , katE , and katF genes were constructed in order to assess the role of hydrogen peroxide in mutagenesis. Mutagenesis was monitored by selecting forward mutations to L‐arabinose resistance. Lethality was measured at experimental conditions equivalent to those of the mutant yield by using a mixed culture of pairs of isogenic strains distinguished by their differential nutritional requirements. Deficiency in katG , katE , and katF genes leads to an enhanced spontaneous mutation rate as well as an enhanced sensitivity to both the lethal and mutagenic effects of hydrogen peroxide or an H 2 O 2 ‐generating mixture of compounds, such as coffee. To compare further the responses of the catalase‐deficient bacteria to those of catalase‐proficient counterparts, other genotoxins were analyzed. Both catalase‐deficient and catalase‐proficient strains were equally mutated by MMS, 4‐NQO, and ultraviolet light. It is concluded that the bacterial strains and the mutagenicity tests described in the paper represent a useful tool to study the role of H 2 O 2 in mutagenesis.