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In this study, the effects of silver nanocolloids (SNCs) on the early life stages of the reef-building coral Acropora japonica were investigated. The tolerance of this species to SNC contamination was estimated by exposing gametes, larvae, and primary polyps to a range of SNC concentrations (0, 0.5, 5, 50, and 500 μg l(-1)). Pure SNCs were immediately ionized to Ag(+) in seawater and concentrations of ≥50 μg l(-1) SNC had a significant detrimental effect on fertilization, larval metamorphosis, and primary polyp growth. Exposure to 50 μg l(-1) SNC did not significantly affect larval survival; however, the larvae were deformed and lost their ability to metamorphose. At the highest concentration (500 μg l(-1) SNC), all gametes, larvae, and primary polyps died. These experiments provide the first data on the effects of silver-nanomaterial-contaminated seawater on cnidarians, and suggest that silver nanomaterials can influence the early development of corals through anthropogenic wastewater inputs., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Prolactin has an antimetamorphic action in amphibian tadpoles. In the Japanese flounder, Paralichthys olivaceus, ovine prolactin (oPRL, 100 ng/ml) antagonized the stimulatory effect of triiodothyronine (T3, 1 ng/ml) on the resorption of the dorsal fin rays of prometamorphic larvae in vitro. Ovine growth hormone (oGH) at the same dose was without effect. Injections with oPRL (50 ng/fish, six times) into prometamorphic larvae also delayed the resorption of the dorsal fin rays without affecting the rates of eye migration and settling, while oGH was again without effect. The changes in the expression of both PRL and GH mRNAs in the pituitary during metamorphosis were monitored by in situ hybridization using cDNA probes. Both PRL and GH genes were increasingly expressed during successive metamorphic stages. These results are discussed in light of the possible interactions of PRL and GH with thyroid hormones in the control of development in the flounder.