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3A - Biomarker/Biomonitoring (TUP/164) Evaluation of Lysosomal membrane integrity as a potential biomarker of multiple stressors in Mytilus edulis. Engell-Kofoed, Anders1, 2, Strand, Jakob1, 2, Dahllöf, Ingela1, 1 National Environmental Research Institute (NERI), Roskilde, Denmark2 Roskilde University, Roskilde, Denmark ABSTRACT- Lysosomes are subcellular organelles that contain hydrolytic enzymes capable of processing damaged or redundant cellular components. Another function of the lysosomes is the capability to accumulate a wide range of toxic compounds, which are damaging to cells. However, the uptake of toxic compounds can affect the lysosomal membrane and result in loss of lysosomal membrane integrity. Effects on lysosomal membrane integrity in molluscan blood cells has been related to exposure of various environmental contaminants such as PAHs, heavy metals and organotins using the neutral red assay. It has been shown that haemocyte lysosomes of stressed mussels have an enhanced uptake of neutral red but show a reduction in neutral red retention time compared to lysosomes from healthy mussels. In the present study we have evaluated the kinetic of neutral red uptake and retention in lysosomes in order to develop a simple absorbance detection based method that allows for large sample numbers for the determination of toxic stress in M. edulis. The method can be seen as a supplement to microscopy methods. The aim is to determine the point during uptake and/or retention where the largest difference between control and treated cells occurs. The method is applied to laboratory experiments where mussels are treated with toxicants in order to elucidate whether long-term treatments eventually will lessen the impact on lysosomal stability due to an adaptive response from the organisms. A field study of lysosomal stability in areas with known impact of contaminants will also be presented. Key words: lysosomes, biomarker, molluscs, neutral red |
