2020 年 23 巻 2 号 p. 38-46
We compared stage-dependent sensitivities of the sea urchin Anthocidaris crassispina to silver nitrate (AgNO3) and silver nanocolloids (SNCs). Our experimental design included three different exposure experiments: (1) pre-fertilization exposures (to assess effects on first cleavage and embryogenesis); (2) exposures of fertilized eggs (to assess effects on cleavage and embryogenesis); and (3) exposures of gastrulae (to assess effects on the gastrula stage and embryogenesis). In the case of the pre-fertilization exposures, exposure of sperm to SNCs induced higher rates of abnormal development than did exposure to AgNO3, and SNCs had higher teratogenicity on pluteus formation than did AgNO3. In the case of the fertilized egg exposures, exposed embryos experienced high rates of cytolysis. These rates exceeded those observed in pre-fertilization exposures of eggs and sperm and were similar to those observed in exposures of sperm alone. In the case of the gastrula exposures, rates of cytolysis were higher than those observed in pre-fertilization exposures of eggs and sperm and lower than those observed in exposures of fertilized eggs and of sperm alone. Sperm exposures showed the highest chemical sensitivity, followed by exposures of gastrulae and of unfertilized eggs and sperm.