title: Insulin-like peptides in Spodoptera littoralis (Lepidoptera): Detection, localization and identification.
abstract: Insulin is an extensively studied peptide hormone in mammals. However, insulin is not restricted to vertebrates, but has also been identified in invertebrates, among whom several insect species. These insulin-like peptides (ILPs) show structural and-at least some-functional homology with mammalian insulin and act through a conserved pathway. Yet many aspects of insulin function in insects remain to be unveiled. We analyzed the presence of ILPs in the cotton leafworm, Spodoptera littoralis, at two levels: (1) cellular localization of ILPs in whole tissues of the central nervous system from S. littoralis, and (2) detection and identification of ILPs at nucleotide level. To our knowledge, nothing about the presence of ILPs in S. littoralis has been described so far. By whole mount in situ immunolocalization, we localized bombyxin-like material in S. littoralis in four pairs of pars intercerebralis cells and in the corpus cardiacum-corpus allatum complexes. In addition, we have cloned two different S. littoralis ILP precursor cDNAs by a combination of PCR and RAcE. The corresponding precursor polypeptides ('Sl-ILPP1' and 'Sl-ILPP2') show significant sequence homology with precursors for bombyxin and other bombyxin-related peptides. Our results strongly suggest that the S. littoralis ILPs belong to the category of bombyxin-analogs.
authors.affiliation: Laboratory of Agrozoology, Department of Crop Protection, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium. sandrien.vandevelde@ugent.be
authors.forename: Sandrien
authors.initials: S
authors.lastname: Van de Velde
authors.forename: Liesbeth
authors.initials: L
authors.lastname: Badisco
authors.forename: Ilse
authors.initials: I
authors.lastname: Claeys
authors.forename: Peter
authors.initials: P
authors.lastname: Verleyen
authors.forename: Xi
authors.initials: X
authors.lastname: Chen
authors.forename: Luc
authors.initials: L
authors.lastname: Vanden Bosch
authors.forename: Jozef
authors.initials: J
authors.lastname: Vanden Broeck
authors.forename: Guy
authors.initials: G
authors.lastname: Smagghe
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000378:metabolism; D003001:Cloning, Molecular; D007301:Insect Hormones / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D007328:Insulin / Q000235:genetics*; D008969:Molecular Sequence Data; D009479:Neuropeptides / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D018411:Spodoptera / Q000235:genetics*; D014018:Tissue Distribution
chemical_list: D007301:Insect Hormones; D007328:Insulin; D009479:Neuropeptides; C075028:bombyxins