title: Neuronal peptides induce oocyte maturation and gamete spawning of sea cucumber, Apostichopus japonicus.
abstract: Extracts prepared from tissues containing buccal ring nerve or longitudinal radial nerve of sea cucumber induce oocyte maturation and ovulation from ovarian tissues. We purified two small peptides, a pentapeptide and a heptapeptide, from the buccal tissues of Japanese common sea cucumber, Apostichopus japonicas. Both peptides induced oocyte maturation and gamete spawning. The pentapeptide was identified as NGIWYamide. This peptide induced in vitro germinal vesicle breakdown and ovulation of fully-grown oocytes at less than 1 pM and in vivo spawning at 10 nM. A synthetic derivative of the pentapeptide, NGLWYamide, was 10-100 times more potent compared to the natural NGIWYamide. The heptapeptide was less potent, inducing ovulation at 1 muM. NGIWYamide and NGLWYamide induced a characteristic spawning behavior when injected into sexually matured individuals. Mature eggs artificially spawned were fertilized, and developed normally and metamorphosed into young sea cucumbers. The details of the production and the mechanism of action of NGIWYamide are still unclear, but the high biopotency of the peptide will aid understanding of the neuronal and hormonal control of reproduction of sea cucumber.
authors.affiliation: Fishery Research Laboratory, Kyushu University, 2506 Tsuyazaki, Fukutsu 811-3304, Japan.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Kato
authors.forename: Saori
authors.initials: S
authors.lastname: Tsurumaru
authors.forename: Makoto
authors.initials: M
authors.lastname: Taga
authors.forename: Tomoki
authors.initials: T
authors.lastname: Yamane
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Shibata
authors.forename: Kaoru
authors.initials: K
authors.lastname: Ohno
authors.forename: Atushi
authors.initials: A
authors.lastname: Fujiwara
authors.forename: Keisuke
authors.initials: K
authors.lastname: Yamano
authors.forename: Michiyasu
authors.initials: M
authors.lastname: Yoshikuni
mesh_terms: D000818:Animals; D005260:Female; D005306:Fertilization / Q000187:drug effects / Q000502:physiology; D005854:Germ Cells / Q000187:drug effects / Q000502:physiology*; D009479:Neuropeptides / Q000494:pharmacology*; D009865:Oocytes / Q000187:drug effects / Q000502:physiology*; D009866:Oogenesis / Q000187:drug effects / Q000502:physiology*; D047528:Stichopus / Q000502:physiology*
chemical_list: D009479:Neuropeptides; C113892:asparaginyl-glycyl-isoleucyl-tryptophyl-tyrosinamide