The identification of ᴅ-tryptophan as a bioactive substance for postembryonic ovarian development in the planarian Dugesia ryukyuensis.
Many metazoans start germ cell development during embryogenesis, while some metazoans possessing pluripotent stem cells undergo postembryonic germ cell development. The latter reproduce asexually but develop germ cells from pluripotent stem cells or dormant primordial germ cells when they reproduce sexually. Sexual induction of the planarian Dugesia ryukyuensis is an important model for postembryonic germ cell development. In this experimental system, hermaphroditic reproductive organs are differentiated in presumptive gonadal regions by the administration of a crude extract from sexual planarians to asexual ones. However, the substances involved in the first event during postembryonic germ cell development, i.e., ovarian development, remain unknown. Here, we aimed to identify a bioactive compound associated with postembryonic ovarian development. Bioassay-guided fractionation identified ʟ-tryptophan (Trp) on the basis of electrospray ionization-mass spectrometry, circular dichroism, and nuclear magnetic resonance spectroscopy. Originally masked by a large amount of ʟ-Trp, ᴅ-Trp was detected by reverse-phase high-performance liquid chromatography. The ovary-inducing activity of ᴅ-Trp was 500 times more potent than that of ʟ-Trp. This is the first report describing a role for an intrinsic ᴅ-amino acid in postembryonic germ cell development. Our findings provide a novel insight into the mechanisms of germ cell development regulated by low-molecular weight bioactive compounds.
Department of Biology, Faculty of Agriculture and Life Science, Hirosaki University, 3 Bunkyo-cho, Hirosaki, Aomori 036-8561, Japan.
Kazuya
K
Kobayashi
Advanced Science Course, Department of Integrated Science and Technology, National Institute of Technology, Tsuyama College, 624-1 Numa, Tsuyama, Okayama 708-8509, Japan.
Takanobu
T
Maezawa
Department of Biochemistry and Molecular Biology, Shiga University of Medical Science, Tsukiwa-cho, Seta, Ohtsu, Shiga 520-2192, Japan.
Hiroyuki
H
Tanaka
RIKEN Genomic Sciences Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan.
Hiroyuki
H
Onuki
Center for Integrated Medical Research, School of Medicine, Keio University, 35 Shinano-machi, Shinjuku-ku, Tokyo 160-8582, Japan.
Yurie
Y
Horiguchi
RIKEN Genomic Sciences Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan.
Hiroshi
H
Hirota
Department of Biochemistry and Molecular Biology, Shiga University of Medical Science, Tsukiwa-cho, Seta, Ohtsu, Shiga 520-2192, Japan.
Tetsuo
T
Ishida
Department of Biochemistry and Molecular Biology, Shiga University of Medical Science, Tsukiwa-cho, Seta, Ohtsu, Shiga 520-2192, Japan.
Kihachiro
K
Horiike
Department of Biochemistry and Molecular Biology, Shiga University of Medical Science, Tsukiwa-cho, Seta, Ohtsu, Shiga 520-2192, Japan.
Yasutoshi
Y
Agata
Department of Biosciences and Informatics, Keio University, 3-14-1 Hiyoshi, Kouhoku-ku, Yokohama 223-8522, Japan.
Manabu
M
Aoki
Department of Biosciences and Informatics, Keio University, 3-14-1 Hiyoshi, Kouhoku-ku, Yokohama 223-8522, Japan.
Motonori
M
Hoshi
Department of Biosciences and Informatics, Keio University, 3-14-1 Hiyoshi, Kouhoku-ku, Yokohama 223-8522, Japan.
Midori
M
Matsumoto
D000818:Animals; D005260:Female; D057850:Hermaphroditic Organisms / Q000254:growth & development / Q000378:metabolism; D008297:Male; D009866:Oogenesis; D010053:Ovary / Q000166:cytology / Q000000981:diagnostic imaging / Q000378:metabolism*; D010932:Planarians / Q000254:growth & development / Q000378:metabolism*; D014364:Tryptophan / Q000378:metabolism*
D014364:Tryptophan