allatostatin-1 and phenylalanyl-leucyl-arginyl-phenylalaninamide

The central complex is a major integrative region within the insect brain with demonstrated roles in spatial orientation, the regulation of locomotor behavior, and sound production. In the hemimetabolous grasshopper, the central complex comprises the protocerebral bridge, central body (CB), ellipsoid body, noduli, and accessory lobes, and this modular organization develops entirely during embryogenesis. From a biochemical perspective, a range of neuroactive substances has been demonstrated in these modules of the adult central complex, but little is known about their developmental expression. In this study, we use matrix-assisted laser desorption/ionization-imaging mass spectrometry on single brain slices to confirm the presence of several peptide families (tachykinin, allatostatin, periviscerokinin/pyrokinin, FLRFamide, and neuropeptide F) in the adult central complex and then use immunohistochemistry and histology to examine their developmental expression, together with that of the indolamin serotonin, and the endogenous messenger nitric oxide (NO; via its synthesizing enzyme). We find that each neuromodulator is expressed according to a unique, stereotypic, pattern within the various modules making up the central complex. Neuropeptides such as tachykinin (55%) and allatostatin (65%), and the NO-synthesizing enzyme diaphorase (70%), are expressed earlier during embryonic development than the biogenic amine serotonin (80%), whereas periviscerokinin-like peptides and FLRFamide-like peptides begin to be expressed only postembryonically. Within the CB, these neuroactive substances are present in tangential projection neurons before they appear in columnar neurons. There is also no colocalization of serotonin-positive and peptide-positive projections up to the third larval instar during development, consistent with the clear dorsoventral layering of the neuropil we observe. Our results provide the first neurochemical fingerprint of the developing central complex in an hemimetabolous insect.

Topics: Animals; Brain; Brain Chemistry; Grasshoppers; Immunohistochemistry; NADPH Dehydrogenase; Neurons; Neuropeptides; Neuropil; Oligopeptides; Serotonin; Tachykinins

The need for more environmentally sound strategies of plant protection has become a driving force in physiological entomology to combat insect pests more efficiently. Since neuropeptides regulate key biological processes, these "special agents" or their synthetic analogues, mimetics, agonists or antagonists may be useful tools. We examined brain-suboesophageal ganglia and corpora cardiaca-corpora allata complexes of the cabbage moth, Mamestra brassicae, in order to obtain clues about possible peptide candidates which may be appropriate for the biological control of this pest. With the aid of bioassays, reversed phase high performance liquid chromatography, and mass spectrometry, five neuropeptides were unequivocally identified and the presence of a further three were inferred solely by comparing mass spectra with known peptides. Only one neuropeptide with adipokinetic capability was identified in M. brassicae. Data from the established homologous bioassay indicated that the cabbage moths rely on a lipid-based metabolism which is aided by an adipokinetic hormone (viz. Manse-AKH) that had previously been isolated in many different lepidopterans. Other groups of neuropeptides identified in this study are: FLRFamides, corazonin, allatostatin and pheromonotropic peptide.

Topics: Amino Acid Sequence; Animals; Biological Assay; Carbohydrate Metabolism; Chromatography, High Pressure Liquid; Cockroaches; Female; Grasshoppers; Hemolymph; Insect Hormones; Insect Proteins; Lipid Metabolism; Male; Mass Spectrometry; Molecular Sequence Data; Moths; Neuropeptides; Neurosecretory Systems; Oligopeptides; Pyrrolidonecarboxylic Acid

A brain-retrocerebral complex-subesophageal ganglion acidified methanolic extract of 100 larval Galleria mellonella (greater wax moth) was prepared for the isolation and identification of (neuro)peptides. To reduce sample complexity, the isolated peptides were roughly separated using a single, conventional chromatographic separation step. Subsequently, screening of these fractions with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry in combination with nanoflow electrospray ionization quadrupole time-of-flight tandem mass spectrometry resulted in the identification of 12 lepidopteran peptides. None of these had been previously isolated or characterized within this species. VIFTPKLamide encoded by the diapause hormone-pheromone biosynthesis activating neuropeptide precursor was for the first time isolated and biochemically identified in a tissue extract, providing irrefutable evidence of its expression in larval nervous tissue. Another pentapeptide, AMVRFamide, with no resemblance to other lepidopteran peptides, was de novo sequenced and is most related to the neuropeptide F peptide family.

Topics: Amino Acid Sequence; Animals; Brain Chemistry; Chromatography, High Pressure Liquid; Ganglia, Invertebrate; Genes, Insect; Head; Insect Proteins; Kinins; Larva; Molecular Sequence Data; Moths; Neuropeptides; Oligopeptides; Spectrometry, Mass, Electrospray Ionization; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization

The pericardial organs (POs) are a pair of neurosecretory organs that surround the crustacean heart and release neuromodulators into the hemolymph. In adult crustaceans, the POs are known to contain a wide array of peptide and amine modulators. However, little is known about the modulatory content of POs early in development. We characterize the morphology and modulatory content of pericardial organs in the embryonic lobster, Homarus americanus. The POs are well developed by midway through embryonic (E50) life and contain a wide array of neuromodulatory substances. Immunoreactivities to orcokinin, extended FLRFamide peptides, tyrosine hydroxylase, proctolin, allatostatin, serotonin, Cancer borealis tachykinin-related peptide, cholecystokinin, and crustacean cardioactive peptide are present in the POs by approximately midway through embryonic life. There are two classes of projection patterns to the POs. Immunoreactivities to orcokinin, extended FLRFamide peptides, and tyrosine hydroxylase project solely from the subesophageal ganglion (SEG), whereas the remaining modulators project from the SEG as well as from the thoracic ganglia. Double-labeling experiments with a subset of modulators did not reveal any colocalized peptides in the POs. These results suggest that the POs could be a major source of neuromodulators early in development.

Topics: Animals; Heart; Nephropidae; Nervous System; Neural Pathways; Neuropeptides; Neurosecretory Systems; Neurotransmitter Agents; Oligopeptides; Serotonin; Tyrosine 3-Monooxygenase