Roger E. Martinelli

Radiation-induced DNA-strand breakage and repair in the marine polychaete, Neanthes arenaceodentata

Abstract We used an alkaline unwinding assay, which provides an index of DNA-strand breakage and repair, to study the genotoxic effects of gamma radiation in adult Neanthes arenaceodentata . To determine radiation-induced DNA-strand damage, we exposed the worms to radiation levels from 3·13 to 100 Gy. Significant DNA-strand damage was found at exposures ≥3·13 Gy. To determine the repair of radiation-induced DNA-strand damage, we irradiated worms at 100 Gy and then harvested and analyzed their DNA on days 0, 2, 5 and 14 post-irradiation. A significant increase in DNA-strand breaks was found to exist between control and radiation-exposed groups on days 0–5. By day 14 post-irradiation, however, no significant relationship was found between control and radiation-exposed groups.

Comparison of Genotoxic Responses of Some Benthic Marine Invertebrates to Radiation

The impact of radiation on the genetic material of a group of benthic inverterbates is under investigation to identify sensitive methods to be used to quantify genotoxic responses both under laboratory conditions and field conditions. Responses that have been compared are the induction of chromosomal aberrations, sister chromatid exchanges, lethal mutations, and DNA strand breakage. Of these, DNA strand breakage appears to be a sensitive and cost-effective method applicable for rapidly assessing radiation-induced damage.