title: Diofenolan induces male offspring production through binding to the juvenile hormone receptor in Daphnia magna.
abstract: Juvenile hormone (JH) and JH agonists have been reported to induce male offspring production in various daphnid species including Daphnia magna. We recently established a short-term in vivo screening assay to detect chemicals having male offspring induction activity in adult D. magna. Diofenolan has been developed as a JH agonist for insect pest control, but its male offspring induction activity in daphnids has not been investigated yet. In this study, we found that the insect growth regulator (IGR) diofenolan exhibited a potent male offspring induction activity at low ng/L to μg/L concentrations, as demonstrated by the short-term in vivo screening assay and the recently developed TG211 ANNEX 7 test protocol. A two-hybrid assay performed using the D. magna JH receptor confirmed that diofenolan had a strong JH activity. Global whole body transcriptome analysis of D. magna exposed to 10 ng/L diofenolan showed an up-regulation of JH-responsive genes and modulation of several genes involved in the ecdysone receptor signaling pathway. These results clearly demonstrate that diofenolan has strong JH activity and male offspring induction activity, and that a combination of modified standardized regulatory testing protocols and rapid in vitro and in vivo screening assays are able to identify potential endocrine disruptors in D. magna. The observation that diofenolan modulates multiple endocrine signaling pathways in D. magna suggests that further investigation of potential interference with growth, development and reproduction is warranted.
authors.affiliation: Environmental Quality Measurement Section, Research Center for Environmental Risk, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba 305-8506, Ibaraki, Japan.
authors.forename: Ryoko
authors.initials: R
authors.lastname: Abe
authors.affiliation: Department of Basic Biology, Faculty of Life Science, Graduate University for Advanced Studies (SOKENDAI), 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Aichi, Japan; Okazaki Institute for Integrative Bioscience, National Institute for Basic Biology, National Institutes of Natural Sciences, and Department of Basic Biology, School of Life Science, Graduate University for Advanced Studies (SOKENDAI), 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Toyota
authors.affiliation: Okazaki Institute for Integrative Bioscience, National Institute for Basic Biology, National Institutes of Natural Sciences, and Department of Basic Biology, School of Life Science, Graduate University for Advanced Studies (SOKENDAI), 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Miyakawa
authors.affiliation: Environmental Quality Measurement Section, Research Center for Environmental Risk, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba 305-8506, Ibaraki, Japan.
authors.forename: Haruna
authors.initials: H
authors.lastname: Watanabe
authors.affiliation: Japan Environmental Management Association for Industry, 2-2-1 Kajicho, Chiyoda-ku, Tokyo 101-0044, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Oka
authors.affiliation: Department of Basic Biology, Faculty of Life Science, Graduate University for Advanced Studies (SOKENDAI), 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Aichi, Japan; Okazaki Institute for Integrative Bioscience, National Institute for Basic Biology, National Institutes of Natural Sciences, and Department of Basic Biology, School of Life Science, Graduate University for Advanced Studies (SOKENDAI), 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Miyagawa
authors.affiliation: Data Integration and Analysis Facility, National Institute for Basic Biology, 38 Nishigonaka, Myodaiji, Okazaki 444-8585, Aichi, Japan.
authors.forename: Hiroyo
authors.initials: H
authors.lastname: Nishide
authors.affiliation: Data Integration and Analysis Facility, National Institute for Basic Biology, 38 Nishigonaka, Myodaiji, Okazaki 444-8585, Aichi, Japan.
authors.forename: Ikuo
authors.initials: I
authors.lastname: Uchiyama
authors.affiliation: Norwegian Institute for Water Research (NIVA), Gaustadallèen 21, N-0349 Oslo, Norway.
authors.forename: Knut Erik
authors.initials: KE
authors.lastname: Tollefsen
authors.affiliation: Department of Basic Biology, Faculty of Life Science, Graduate University for Advanced Studies (SOKENDAI), 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Aichi, Japan; Okazaki Institute for Integrative Bioscience, National Institute for Basic Biology, National Institutes of Natural Sciences, and Department of Basic Biology, School of Life Science, Graduate University for Advanced Studies (SOKENDAI), 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan.
authors.forename: Taisen
authors.initials: T
authors.lastname: Iguchi
authors.affiliation: Environmental Quality Measurement Section, Research Center for Environmental Risk, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba 305-8506, Ibaraki, Japan. Electronic address: tatarazako.norihisa@nies.go.jp.
authors.forename: Norihisa
authors.initials: N
authors.lastname: Tatarazako
mesh_terms: D000818:Animals; D060829:Arthropod Proteins / Q000235:genetics; D003621:Daphnia / Q000187:drug effects*; D052244:Endocrine Disruptors / Q000633:toxicity; D007605:Juvenile Hormones / Q000378:metabolism; D008297:Male; D010671:Phenylurea Compounds / Q000633:toxicity*; D012098:Reproduction / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects; D059467:Transcriptome; D015854:Up-Regulation / Q000187:drug effects; D014874:Water Pollutants, Chemical / Q000633:toxicity
chemical_list: D060829:Arthropod Proteins; D052244:Endocrine Disruptors; D007605:Juvenile Hormones; D010671:Phenylurea Compounds; D014874:Water Pollutants, Chemical; C471807:diofenolan
keywords: IGR; Insecticide; Juvenile hormone receptor; Juvenile hormone-responsive genes; Reproduction; Two-hybrid assay