MP7 Toxicogenomics in Environmental Studies
Monday, 14 November 2005: 8:00 AM - 5:30 PM in Exhibit Hall

(TSY-1117-852590) Radiation-induced DNA stand-breakage in Japanese medaka (Oryzias latipes).

Tsyusko, O.¹, Glenn, T.¹, Hinton, T.¹, Coughlin, D.¹, ¹ Savannah River Ecology Laboratory, The university of Georgia, Aiken, SC, USA

ABSTRACT- During the last decades, there has been a need for rapid and simple tests to evaluate the effects of exposure to environmental contaminants which can have an adverse health impacts due to DNA damage. Comet assay, a sensitive method for detecting DNA damage in individual cells, allows the detection of diverse DNA alterations including double and single strand breaks, alkali-labile sites, and incomplete repair sites. By quantifying strand breaks for relatively many cells, standard statistical approaches can be used to quantify differences within and among individuals and treatments. This method was used to detect total DNA damage due to radiation exposure in Japanese medaka (Oryzias latipes), one of the most widely used fish in comparative mutagenesis, carcinogenesis, and genomic instability studies. The adult fish was irradiated at three different dose rates, and their red blood cells were subjected to the Comet assay. Our preliminary data showed elevated level of DNA damage in irradiated medaka cells when compared to that of control fish. Relatively minor DNA damage was observed at low-dose rates suggesting that exposure to environmentally relevant radiation doses has the potential to induce DNA strand breakage in medaka. The amount of the DNA damage increased with increasing dose rate. Further work is necessary to determine if the Comet assay can be used as bio-indicator for radiation-induced DNA damage in medaka.

Key words: Oryzias latipes, Comet assay, DNA strand breakage, radiation