title: Sex Reversal and Analyses of Possible Involvement of Sex Steroids in Scallop Gonadal Development in Newly Established Organ-Culture Systems.
abstract: Many molluscs perform sex reversal, and sex hormones may be involved in the process. In adult scallops, Patinopecten yessoensis, gonadotropin releasing hormone and 17β-estradiol (E2) are involved in male sexual maturation, however, little is known about the effects of E2and testosterone (T) on the gonadal differentiation in young scallops. In the present study, scallop gonadal development was analyzed to determine the sex reversal stage in Funka bay, and effects of E2and T were examined. In Funka bay, almost all scallops were male at month 12. Scallops equipped with ambiguous gonads were 61.1% at month 16 and disappeared at month 18. Therefore, sex reversal in Funka bay occurs at around month 16. For establishment of organ culture systems for bivalves, Manila clam gonads were cultured in 15% L-15 medium diluted with HBSS containing 10% KSR on agarose gel at 10°C, and the gonads survived for 14 days. Scallop gonads were also able to be cultured in 30% L15 medium diluted with ASW containing 10% KSR on agarose gel for seven days. At mature stage, Foxl2 and Tesk were predominantly expressed in ovary and testis, respectively. When scallop gonads at sex reversal stage were organ-cultured, sex steroid treatment decreased Tesk expression in the majority of scallop gonads at sex reversal stage. However, no obvious change in Foxl2 and Tesk expression was detected in mature gonads in response to either E2or T in culture, suggesting sex steroid treatment might affect gonadal development at sex reversal stage.
authors.affiliation: 1 Department of Biological Science and Technology, Faculty of Industrial Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan.
authors.forename: Ayano
authors.initials: A
authors.lastname: Otani
authors.affiliation: 1 Department of Biological Science and Technology, Faculty of Industrial Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan.
authors.forename: Tadaaki
authors.initials: T
authors.lastname: Nakajima
authors.affiliation: 1 Department of Biological Science and Technology, Faculty of Industrial Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan.
authors.forename: Tomomi
authors.initials: T
authors.lastname: Okumura
authors.affiliation: 2 Department of Liberal Arts Education, Faculty of Industrial Science and Technology, Tokyo University of Science, 102-1 Tomino, Oshamambe-cho, Yamakoshi-gun, Hokkaido 049-3514, Japan.
authors.forename: Shiro
authors.initials: S
authors.lastname: Fujii
authors.affiliation: 1 Department of Biological Science and Technology, Faculty of Industrial Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Tomooka
mesh_terms: D000818:Animals; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D006066:Gonads / Q000187:drug effects* / Q000502:physiology*; D008297:Male; D009924:Organ Culture Techniques / Q000379:methods*; D049897:Pectinidae / Q000502:physiology*; D012733:Sex Differentiation / Q000187:drug effects; D013739:Testosterone / Q000494:pharmacology*
chemical_list: D013739:Testosterone; D004958:Estradiol
keywords: gonadal development; organ culture; scallop; sex reversal; sex steroid