title: Participation of D-serine in the development and reproduction of the silkworm Bombyx mori.
abstract: The silkworm Bombyx mori contains high concentrations of free D-serine, an optical isomer of L-serine. To elucidate its function, we first investigated the localization of D-serine in various organs of silkworm larvae, pupae, and adult moths. Using immunohistochemical analysis with an anti-D-serine antibody, we found D-serine in the microvilli of midgut goblet and cylindrical cells and in peripheral matrix components of testicular and ovarian cells. By spectrophotometric analysis, D-serine was also found in the hemolymph and fat body. D-Alanine was not detected in the various organs by immunohistochemistry. Serine racemase, which catalyzes the inter-conversion of L- and D-serine, was found to co-localize with D-serine, and D-serine production from L-serine by intrinsic serine racemase was suggested. O-Phospho-L-serine is an inhibitor of serine racemase, and it was administered to the larvae to reduce the D-serine level. This reagent decreased the midgut caspase-3 level and caused a delay in spermatogenesis and oogenesis. The reagent also decreased mature sperm and egg numbers, suggesting D-serine participation in these processes. D-Serine administration induced an increase in pyruvate levels in testis, midgut, and fat body, indicating conversion of D-serine to pyruvate. On the basis of these results, together with our previous investigation of ATP biosynthesis in testis, we consider the possible involvement of D-serine in ATP synthesis for metamorphosis and reproduction.
authors.affiliation: Department of Materials and Applied Chemistry, College of Science and Technology, Nihon University, Chiyoda-Ward, Tokyo 101-8308, Japan.
authors.forename: Minoru
authors.initials: M
authors.lastname: Tanigawa
authors.affiliation: Department of Materials and Applied Chemistry, College of Science and Technology, Nihon University, Chiyoda-Ward, Tokyo 101-8308, Japan.
authors.forename: Chihiro
authors.initials: C
authors.lastname: Suzuki
authors.affiliation: Department of Materials and Applied Chemistry, College of Science and Technology, Nihon University, Chiyoda-Ward, Tokyo 101-8308, Japan.
authors.forename: Kimio
authors.initials: K
authors.lastname: Niwano
authors.affiliation: Department of Applied Biology, Faculty of Textile Science and Technology, Shinshu University, Ueda, Nagano 386-8567, Japan.
authors.forename: Rensuke
authors.initials: R
authors.lastname: Kanekatsu
authors.affiliation: Department of Biochemistry and Molecular Biology, Shiga University of Medical Science, Seta, Shiga 520-2192, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tanaka
authors.affiliation: Department of Biochemistry and Molecular Biology, Shiga University of Medical Science, Seta, Shiga 520-2192, Japan.
authors.forename: Kihachiro
authors.initials: K
authors.lastname: Horiike
authors.affiliation: Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Hamase
authors.affiliation: Department of Materials and Applied Chemistry, College of Science and Technology, Nihon University, Chiyoda-Ward, Tokyo 101-8308, Japan. Electronic address: ocean_nagata@axel.ocn.ne.jp.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Nagata
mesh_terms: D000818:Animals; D012831:Bombyx / Q000254:growth & development*; D005260:Female; D008297:Male; D012098:Reproduction; D012694:Serine / Q000378:metabolism*
chemical_list: D012694:Serine
keywords: Morphogenesis; Pyruvate; Serine racemase; Silkworm; Spermatogenesis; d-Serine; d-Serine dehydratase