Excision of an oxidative DNA lesion (8-oxo-deoxyguanosine) in Mytilus edulis populations from two sites in the eastern Irish Sea

Abstract

Mussels (Mytilus edulis) from the urban/industrialised site of New Brighton, Merseyside, UK and the reference site of Llandudno, North Wales, UK were collected at various time-points in 2005-2006. The excision capacity of mussel gill towards a radio-labelled probe containing the oxidative lesion 8-oxo-dG (8-oxo-deoxyguanosine) was quantified for both populations within 24 h of collection. Fpg (formamidopyrimidine glycosylase)-sensitive sites (which are proportional to 8-oxo-dG levels) were also quantified via the Fpg-modified Comet assay. Generally, excision capacity in New Brighton mussels was lower compared to Llandudno mussels, with the exception of May when activities from both groups were at their lowest. No substantial differences between Fpg-sensitive sites were noted but the ratio mean Fpg-sensitive sites/mean 8-oxo-dG excision capacity was elevated for New Brighton mussels. It is possible that the evident oxidative stress these mussels undergo is linked to pollutants found in their natural environment. These pollutants may act not only by direct oxidative DNA damage but also by down-regulation of DNA repair pathways.