DNA Damage–Inducible Gene Expression and Formation of 5-Fluorouracil–Resistant Mutants in Escherichia coli Exposed to 2-Dodecylcyclobutanone

2-Dodecylcyclobutanone (2-DCB) is formed by the radiolysis of palmitic acid and is present at low part-per-million (approximately 0.1 g/g) levels in irradiated meat products. Recently, equivocal results obtained using a DNA strand breakage test, the Comet Assay, raised the possibility that 2-DCB could be a weak genotoxin. To more accurately assess 2-DCB’s potential genotoxicity, it was tested for the ability to increase expression of the DNA damage–inducible genes dinD, nfo, recA, and umuDC using Escherichia coli that contained promoter/ -galactosidase reporter constructs, and for the ability to increase the formation of 5-fluorouracil (5-FU)–resistant mutants. When E. coli was exposed to 125, 250, 500, and 1000 g/mL 2-DCB, with and without exogenous metabolic activation, no increase in dinD, nfo, recA, or umuDC gene expression, as measured by an increase in -galactosidase activity, was observed. In addition, 2-DCB did not increase the formation of 5FU–resistant mutants in E. coli, with and without exogenous metabolic activation, at the same concentrations. No evidence of 2-DCB–associated genotoxic activity was detected in this study.