Vazquez Lourdes C
Water Quality Laboratory, Department of Environmental Services, City and County of Honolulu, 1350 Sand Island Parkway Building 9, Honolulu, Hawaii 96819, USA.
Environ Toxicol Chem. 2003 Sep;22(9):2191-4. doi: 10.1897/02-614.
The sea urchin sperm fertilization bioassay is an approved U.S. Environmental Protection Agency (U.S. EPA) biomonitoring tool for regulatory and compliance purposes. The method adapted for the Hawaiian species Tripneustes gratilla recommends a sperm-to-egg ratio of 2,500. Using a fixed ratio for all tests does not sufficiently account for seasonal and individual variabilities of this organism. Our studies showed that gametes must be present at specific concentrations, which are unique for each batch. Parallel experiments were conducted to compare tests using a constant 2,500 sperm-to-egg ratio with tests using an optimized sperm dosage determined prior to each analysis. The recommended 2,500 sperm-to-egg ratio often gave overfertilized controls and reduced toxicological response. The risks of oversperming and concomitant toxicity masking were minimized when the bioassays were performed with optimum sperm-to-egg ratio.
海胆精子受精生物测定法是美国环境保护局（U.S. EPA）批准的一种用于监管和合规目的的生物监测工具。适用于夏威夷物种T. gratilla的方法建议精子与卵子的比例为2500。对所有测试使用固定比例并不能充分考虑该生物的季节性和个体变异性。我们的研究表明，配子必须以特定浓度存在，而每个批次的特定浓度都是独特的。进行了平行实验，以比较使用恒定的2500精子与卵子比例的测试和使用每次分析前确定的优化精子剂量的测试。推荐的2500精子与卵子比例常常导致对照过度受精，并降低毒理学反应。当以最佳精子与卵子比例进行生物测定时，过度授精和伴随的毒性掩盖风险降至最低。
