Research output

Article in Journal ()

Mitochondrial DNA mutation frequencies in experimentally irradiated compost worms, Eisenia fetida

Citation
Wilding CS, Trikic MZ, Hingston JL, Copplestone D & Tawn EJ (2006) Mitochondrial DNA mutation frequencies in experimentally irradiated compost worms, Eisenia fetida, Mutation Research - Genetic Toxicology and Environmental Mutagenesis, 603 (1), pp. 56-63.

Abstract
The compost worm Eisenia fetida is routinely used in ecotoxicological studies. A standard assay to assess genetic damage in this species would be extremely valuable. Since mitochondrial DNA (mtDNA) is known to exhibit an increased mutation rate following exposure to ionising radiation we assessed the validity of a mtDNA-based assay for measuring increases in mutation rate in laboratory-irradiated compost worms. To this end the mutation frequency in the mtDNA of the compost worm E. fetida was quantified following in vivo γ-irradiation of adult worms in three dose groups. Five adult worms exposed to 1.4 mGy/h for 55 days (total dose 1.85 Gy), five adult worms exposed to 8.5 mGy/h for 55 days (total dose 11.22 Gy) and five adult control worms were used to assess the effect of irradiation on mtDNA mutation induction. DNA samples extracted from irradiated adult worms were used in high-fidelity PCR of a 486 bp region of mtDNA spanning the ATPase 8 gene, chosen for its high spontaneous mutation rate. PCR products were cloned and sequenced to identify mutations, with 89–102 clones successfully sequenced per individual. A significant elevation in mtDNA mutation frequency (p = 0.032) was seen in worms exposed at the higher dose rate (8.5 mGy/h, total dose 11.22 Gy; mutation frequency 27.98 ± 4.85 × 10−5 mutations/bp) in comparison to controls (mutation frequency 12.68 ± 3.06 × 10−5 mutations/bp), but no elevation in mutation frequency (p = 0.764) was seen for the lower dose rate (1.4 mGy/h, total dose 1.85 Gy; mutation frequency 13.74 ± 1.29 × 10−5 mutations/bp) compared with controls. This indicates that although the technique has the potential to detect an elevation in mutation frequency, it does not have sufficient sensitivity at the doses likely to be encountered in environmental monitoring scenarios.

Keywords
annelid; biomarker; compost worm; ionising radiation; mitochondrial DNA; mutation

StatusPublished
AuthorsWilding Craig S, Trikic Michael Z, Hingston Joanne L, Copplestone David, Tawn E Janet
Publication date31/01/2006
PublisherElsevier
ISSN 1383-5718
LanguageEnglish

Journal
Mutation Research - Genetic Toxicology and Environmental Mutagenesis: Volume 603, Issue 1 (JAN 31 2006)

© University of Stirling FK9 4LA Scotland UK • Telephone +44 1786 473171 • Scottish Charity No SC011159
My Portal