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(336) Integrating life-cycle and diagnostic approaches to establish the relevance of earthworm biomarker tools . Spurgeon, David1, Morgan, A2, Sturzenbaum, Stephen 2, Svendsen, Claus1, Kille, Peter2, Weeks, Jason3, 1 2 3 ABSTRACT- Approaches to assessing the impact of metals on human health (toxicology) and the environment (ecotoxicology) have differed, with the focus in human toxicology on establishing molecular mechanisms for metal handing and in ecotoxicology on evaluating whole organism responses. Here we show interrelationship between these approaches in a multi-disciplinary study, in which life-cycle, organelle (lysosome membrane integrity) and molecular (gene expression) responses are assessed in a functionally important terrestrial macroinvertebrate exposed to copper and cadmium. Results show concentration dependent impacts forlife-cycle traits such a sexual maturation, fecundity and adult and juvenile reproduction that underlie population fitness. Further reductions in lysosomal integrity and changes in gene abundance for both metals are also demonstrated. Statistical comparisons between the different responses measured, reveal significant linkage between expression and both lysosomal integrity and population performance, with strongest correlation for genes, such as that encoding the metal chelating protein metallothionein, in which a mechanistic link with metal detoxification is recognised. By establishing inter-linkages between biological responses, this study indicates the presence of hierarchical response cascade in organisms subjected to contaminant stress. Such a cascade, in which molecular changes underpin life-cycle responses, offer the potential to use genetic tools as diagnostic indicators of pollutant exposure. Key words: Earthworm, Biomarker, Fitness, Gene expression |
