32P-Postlabeling Analysis of Aromatic DNA Adducts in Fish from Polluted Areas

摘要

Brown bullheads (Ictalurus nebulosus) were sampled from sites in the Buffalo and Detroit Rivers where fish are exposed to high levels of sediment bound polycyclic aromatic hydrocarbons, and suffer from an elevated frequency of liver cancer. DNA was isolated from the livers of these wild fish and from control specimens which were raised in clean aquariums. DNA was enzymatically digested to normal and adducted nucleotides, and hydrophobic/bulky adducts were enriched in the digests either by preparative reverse-phase high-pressure liquid chromatography, or selective nuclease P1 dephosphorylation of normal nucleotides. Aromatic DNA-carcinogen adducts were then quantitated using (32)P-postlabeling analysis. Using both adduct enrichment procedures, chromatograms derived from DNA of fish from polluted areas showed a diffuse diagonal radioactive zone not present in DNA from aquarium raised fish.