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2C - Biomarkers (TUP/89) Gene expression studies in Daphnia magna: linking biomarkers with ecological relevance. Connon, Richard1, Hooper, Helen1, Sibly, Richard1, Callaghan, Amanda1, 1 The University of Reading, Reading, Berkshire, UK ABSTRACT- Toxic responses are often preceded by alterations in gene expression, thus studies based on gene expression may offer insights into the overall health of an organism and therefore that of a community and population. Gene expression studies carried out over short term exposures may sometimes allow the prediction of the chronic effects toxicants may have over the overall health of a population. Gene expression can sometimes be used as biomarkers of pollution, providing an early warning of changing environmental contamination and even help to identify chemicals responsible for the measured toxicity. A number of genes were selected from Daphnia magna exposed to 25 % kerosene water-soluble fraction by means of subtractive hybridisation. Quantitative PCR has been used as a tool to investigate the expression responses of D. magna exposed to varying kerosene dose and time-course parameters. A significant increase in haemoglobin synthesis resulted from 24 h exposure to 12.5 % soluble kerosene fraction suggesting that kerosene prevents the uptake of dissolved oxygen by the filter-feeding water-fleas. Since haemoglobin plays a mayor part in embryonic development, measurements of haemoglobin synthesis may be used as a biomarker on neonate D. magna, to predict the effect kerosene may have on reproduction and thus population dynamics. Key words: daphnia magna, gene expression, haemoglobin, population dynamics |
