T2 AM 'Omic' Technologies: Current and Future Application to Environmental Toxicology (Part 1)
Tuesday, 15 November 2005: 8:00 AM - 11:40 AM in Ballroom 2

(CHI-1118-083046) Biomarkers from (eco)toxicogenomics : the European flounder as a non-model organism and the distinction between compensatory versus toxic responses.

Chipman, J K¹, George, S G ², Williams, T D¹, Diab, A.M. ², Sabine, V², Godfrey, R E¹, Minchin, S D¹, ¹ School of Biosciences, University of Birmingham, Birmingham, UK² University of Stirling, Stirling, Scotland

ABSTRACT- There is increasing interest in gaining information on altered gene expression in response to exposure to toxic chemicals. These studies will aid identification of toxic mechanisms and the development of novel, sensitive and early biomarkers for use in screening and in environmental monitoring. Information is relatively forthcoming in model organisms for which adequate databases are available. However, toxicogenomics in organisms of environmental relevance is more difficult. We initiated studies in the flounder by designing degenerate primers for a range of genes of toxicological interest. In addition, subtractive suppressive hybridisations (SSH) between flounder collected from the Alde (reference) and Tyne (polluted) estuaries provided clones of differentially expressed genes, as did SSH between flounder treated with benzo(a)pyrene or cadmium in comparison to controls. These clones were combined with clones from a liver cDNA library to produce a 13,000 cDNA microarray for the flounder (EU-GENIPOL Project). Proof of principle has been achieved by comparing the differences in gene expression between flounder sampled from estuaries of different pollution status and also between flounder treated in the laboratory with model toxicants. We have detected induction of known biomarker genes, eg. CYP1A with PAH treatments, metallothionein with cadmium, vitellogenin and choriogenin with estradiol and ethinyl-estradiol. Importantly, interactive effects have been discovered e.g. between PAH and metals. Bioinformatics analyses including gene ontology have been initiated as more complete sequencing of clones is being achieved. Activated processes are being identified and correlations are emerging between laboratory and field responses e.g. induction of CYP1A, Cu/Zn SOD. Potential novel biomarkers have been indicated such as HSP 30B, fatty acid binding protein and other, yet to be characterised, ESTs. A major challenge is the integration of such studies into risk assessment for example in the derivation of novel batteries of biomarkers. However, to achieve this, it is necessary to distinguish between compensatory and toxic responses and these issues will be illustrated with reference to CYP and HSP induction. This work was funded by the NERC, CEFAS and EU and has involved GENIPOL collaborations.

Key words: flounder, toxicogenomics, biomarkers, array