Hydrazine and Methylhydrazine as recA+ Independent Mutagens in Escherichia coli
Hydrazine (H2N-NH2) and methylhydrazine (CH3-HN-NH2) are both carcinogenic (IARC Monograph Vol.4, 1974). They react with pyrimidine bases in DNA causing ring opening and loss of pyrimidines, or more commonly, forming different adducts. Some of these adducts, especially N4-aminocytosine are suspected to cause mutations by a base mispairing mechanism (see the review of Kimball, 1977). In this work the mutagenic action of hydrazine and methylhydrazine was studied using both bacterial and phage test systems. Both the bacterial test strains and the phage hosts used in the experiments differed in their repair capacities and in their expression of the postulated recA + -dependent, error-prone, inducible repair system (“SOS repair”) (Radman, 1975). The aim of the work has been to find out whether “SOS repair” is involved in the mutagenic action of hydrazine.
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