THE USE OF A LYSOSOME ASSAY FOR THE RAPID ASSESSMENT OF CELLULAR STRESS FROM COPPER TO THE FRESH-WATER SNAIL VIVIPARUS-CONTECTUS (MILLET)

To enable efficient monitoring and the early detection of toxic metal effects a rapid low cost test has been developed for use with freshwater gastropods. A cellular assay formerly developed for marine organisms has been modified for use with freshwater snails. A modified neutral-red retention assay makes use of the fact that lysosomes in unstressed cells retain the neutral-red dye for a long duration after uptake. In contrast, following uptake in stressed cells, the dye will leak from the lysosomes into the cytoplasm more rapidly, an indication of cell-membrane damage. The higher the stress level, the shorter the period of dye retention. In this study freshwater snails Viviparus contectus were exposed to dissolved copper. Blood cells extracted from snails exposed to the highest concentrations exhibited the shortest lysosomal neutral-red retention times. This early detectable change may be useful for routine environmental monitoring, identifying low level contamination, the moment it occurs.