Ade Yamindago, Nayun Lee, Seonock Woo, Hyosun Choi, Ji Young Mun, Seok-Won Jang, Sung Ik Yang, Friederike Anton-Erxleben, Thomas C.G. Bosch, Seungshic Yum
Zinc oxide nanoparticles (ZnO NPs) are increasingly used in various products as coating and additive materials for household goods, personal-care products, and drug delivery systems. Because of their broad applications, the potential risks to nontarget organisms associated with their input into aquatic environments have generated much concern. We investigated the acute toxicity, morphological responses, and potential impact on physiology and metabolism in polyps exposed to spherical ZnO NPs of either 20 nm (ZnO NP20) or 100 nm (ZnO NP100). The median lethal concentrations (LC50) of ZnO NP20 were 55.3, 8.7, and 7.0 μg/mL after exposure for 48, 72, and 96 h, respectively; and those of ZnO NP100 were 262.0, 14.9, and 9.9 μg/mL, respectively. The morphological responses of the hydra polyps to a range of ZnO NP concentrations suggest that ZnO NPs may negatively affect neurotransmission in Hydra. ZnO NPs may also induce abnormal regeneration in the polyps by affecting the expression of several genes related to the Wnt signaling pathway. The presence of ZnO NP20 in the hydra tissue was confirmed with electron microscopy. A Gene Ontology analysis of the genes differentially expressed in hydra polyps after exposure to ZnO NP20 for 12 or 24 h revealed changes in various processes, including cellular and metabolic process, stress response, developmental process, and signaling. A KEGG pathway analysis of hydra polyps after exposure of ZnO NP20 or ZnO NP100 for 12 or 24 h demonstrated various changes, including in the DNA replication and repair, endocytosis, lysosomes, Wnt signaling, and natural killer-cell-mediated cytotoxicity pathways, suggesting the mechanisms that maintain cellular homeostasis in response to ZnO NPs. Progesterone-mediated oocyte maturation was also affected by the ZnO NPs nanoparticles, suggesting that they are potential endocrine disruptors. This study should increase our concern regarding the dispersal of ZnO NPs in aquatic environments. © 2018 Elsevier B.V.
South Sea Environment Research Center, Korea Institute of Ocean Science and Technology (KIOST), Geoje, 53201, South Korea; Faculty of Marine Environmental Science, University of Science and Technology (UST), Geoje, 53201, South Korea; Faculty of Fisheries and Marine Science, Brawijaya University, Malang, 65145, Indonesia; Marine Biotechnology Research Center, Korea Institute of Ocean Science and Technology (KIOST), Busan, 49111, South Korea; BK21 Plus Program, Department of Senior Healthcare, Graduate School, Eulji University, Daejeon, 34824, South Korea; Department of Structure and Function of Neural Network, Korea Brain Research Institute, Dong-gu, Daegu, 41068, South Korea; Department of Applied Chemistry, Kyung Hee University, Yongin, 17104, South Korea; Zoological Institute, Christian-Albrechts University of Kiel, Kiel, D-24118, Germany
