Identification of a Prothoracicostatic Peptide in the Larval Brain of the Silkworm,Bombyx mori

Yue-Jin Hua, Yoshiaki Tanaka, Keiji Nakamura, Mika Sakakibara, Shinji Nagata, Hiroshi Kataoka
1999 Journal of Biological Chemistry  
Prothoracicotropic hormone (PTTH) stimulates ecdysteroid biosynthesis in the prothoracic gland (PG) of insects. A peptide inhibiting ecdysteroid biosynthesis in the PG was isolated from the extracts of 2,000 larval brains of the silkworm, Bombyx mori, using a protocol that included four reversed-phase high performance liquid chromatography procedures. The primary structure of this prothoracicostatic peptide (Bom-PTSP) was determined to be H-Ala-Trp-Gln-Asp-Leu-Asn-Ser-Ala-Trp-NH 2 . This
more » ... -NH 2 . This neuropeptide has the same sequence as Mas-MIP-I, a myoinhibitory peptide previously isolated from the ventral nerve cord of the tobacco hornworm, Manduca sexta, and is highly homologous with the Nterminal portion of vertebrate peptides of the galanin family. This peptide inhibited PTTH-stimulated ecdysteroidogenesis in the PG at both the spinning and feeding stages, which indicates that Bom-PTSP interferes with PTTH-stimulated ecdysteroidogenesis. Ecdysteroid RIA The ecdysteroid RIA was performed as described by Takeda et al. (15). The cross-reactivity ratio between ecdysone and 20-hydroxyecdysone is 1:2.5 (15). The results are expressed as ecdysone equivalents. a The activation ratio is significantly different from that of the respective control (without PTSP); p Ͻ 0.01. b The activation ratio is significantly different from that of the respective control (without PTSP); p Ͻ 0.05. We suggest that subscribers photocopy these corrections and insert the photocopies at the appropriate places where the article to be corrected originally appeared. Authors are urged to introduce these corrections into any reprints they distribute. Secondary (abstract) services are urged to carry notice of these corrections as prominently as they carried the original abstracts. 9892
doi:10.1074/jbc.274.44.31169 pmid:10531308 fatcat:3bwnsc6c5nay5p4jsnekxv77pa