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(M/EH018) Embryotoxicity test with sea urchins: a reduced bioassay. Manzo, Sonia1, Torricelli, Leonardo1, 1 ABSTRACT- The use of sea urchin embryos and gametes in testing developmental, reproductive and cytogenetic effect of pollutants has been successfully developed by a number of laboratories worldwide. Bioassays with sea urchin embryos show many advantages but routine use of sea urchin embryos toxicity test isn't very developed, probably because of laboriousness of method. In the present study, we investigated the possibility to realize an easier methodology for routine application of the method. Mediterranean sea urchin Paracentrotus lividus were collected in the Bay of Naples. After acclimatization male and female were induced to spawn. Pools of three female eggs and three male sperm were then mixed together. After 10 min, counting 100 eggs determinate fertilization rate. Five concentrations (plus a blank) of chemical substances to test were prepared, with six replicates for each concentration. We added under stereomicroscope, 10 fertilized eggs to each chamber test (5 ml). We incubate the samples at 18°C. After 48 h we evaluated the dead and determinated the EC50. We tested the sensibility of the New Embryotoxicity Test (NET) with different chemical substances (K2Cr2O7, CuSO4, etc.) and different natural samples. In all cases we started from a good fertilization rate (>90%). Fertilized eggs selected at the beginning of test produced, after 48 h in control chamber, healthy pluteus with satisfying rate. This shows that further manipulation of fertilized eggs in NET doesn't produce any damage, but it allows exposing a restricted number of surely fertilized eggs to different concentrations and makes easier and faster the final counting of dead and alive organisms. Our results are in good accordance with that obtained with traditional methodologies; NET might be a first step to carrying out a new routine ecotoxicological kit for sea-waters. Key words: Paracentrotus lividus , Embriotoxicity, Sea Water |
