LACK OF UNIFORMITY IN THE MUTATIONAL SPECTRA OF CHLOROHYDROXYFURANONES IN SALMONELLA-TYPHIMURIUM STRAIN TA100

The mutational specificity of three chlorohydroxyfuranones found in chlorinated drinking water, 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX), 3-chloro-4(chloromethyl)-5-hydroxy-2(5H) -furanone (CMCF) and 3,4-dichloro-5-hydroxy-2(5H)-furanone (mucochloric acid, MCA), was examined in Salmonella typhimurium strain TA100, DNA colony-hybridization of TA100 revertants showed that MX and CMCF both induced predominantly G:C --> T:A transversions (87 and 75% of total, respectively) with a 3:1 preference for the second position of the hisG46 (CCC) target codon. By contrast, MCA produced primarily G:C --> A:T transitions (66% of the total) with a 4:1 preference for the second position of the CCC codon, The mutational specificity of MCA is consistent with the idea that chloroacetaldehyde, a degradation product of MCA, is responsible for the observed mutations. The chemical mechanism by which either MX or CMCF induces G:C --> T:A transversions remains unknown.