title: Life cycle expression of a bombyxin-like neuropeptide in the tobacco hornworm, Manduca sexta.
abstract: Immunocytochemistry was used to investigate the developmental expression of the insulin-like neuropeptide bombyxin in the tobacco hornworm, Manduca sexta. A mouse monoclonal antibody raised against a synthetic peptide corresponding to bombyxin's A-chain N-terminus was used to localize a bombyxin-like peptide to a group of cerebral medial neurosecretory cells, the M-NSC IIa(2). Immunostaining was first detected on day 0 of the second larval instar, localized in the M-NSC IIa(2) somata and in the neurohemal organ, the corpora allata (CA). By day 0 of the fourth larval instar, the peptide was present throughout the M-NSC IIa(2) somata, axons, dendritic fields and CA. Between days 7 and 9 of the fifth instar, a dramatic reduction in the dendritic fields and CA staining occurred, suggesting the peptide is released. After day 2 of the pupal period, only M-NSC IIa(2) somata immunostained, a pattern that persisted through day 2 of the adult stage. The specificity of immunostaining was demonstrated by using a synthetic bombyxin peptide to block staining. These developmental data reveal times of potential Manduca bombyxin-like peptide release which should provide insight into the peptide's function.
authors.affiliation: Department of Biology CB# 3280, Coker Hall, 010A University of North Carolina at Chapel Hill, Chapel Hill, U.S.A.
authors.forename: W E.
authors.initials: WE
authors.lastname: Bollenbacher
authors.forename: R S.
authors.initials: RS
authors.lastname: Gray
authors.forename: L R.
authors.initials: LR
authors.lastname: Whisenton
authors.forename: D P.
authors.initials: DP
authors.lastname: Muehleisen
authors.forename: B V.
authors.initials: BV
authors.lastname: Nogueira