crustacean-cardioactive-peptide and corazonin-protein--insect

Topics: Animals; Behavior, Animal; Ecdysterone; Endocrine System; Insect Hormones; Insect Proteins; Insecta; Invertebrate Hormones; Larva; Molting; Neuropeptides

Neuropeptides are among the structurally most diverse signaling molecules and participate in intercellular information transfer from neurotransmission to intrinsic or extrinsic neuromodulation. Many of the peptidergic systems have a very ancient origin that can be traced back to the early evolution of the Metazoa. In recent years, new insights into the evolution of these peptidergic systems resulted from the increasing availability of genome and transcriptome data which facilitated the investigation of the complete neuropeptide precursor sequences. Here we used a comprehensive transcriptome dataset of about 200 species from the 1KITE initiative to study the evolution of single-copy neuropeptide precursors in Polyneoptera. This group comprises well-known orders such as cockroaches, termites, locusts, and stick insects. Due to their phylogenetic position within the insects and the large number of old lineages, these insects are ideal candidates for studying the evolution of insect neuropeptides and their precursors. Our analyses include the orthologs of 21 single-copy neuropeptide precursors, namely ACP, allatotropin, AST-CC, AST-CCC, CCAP, CCHamide-1 and 2, CNMamide, corazonin, CRF-DH, CT-DH, elevenin, HanSolin, NPF-1 and 2, MS, proctolin, RFLamide, SIFamide, sNPF, and trissin. Based on the sequences obtained, the degree of sequence conservation between and within the different polyneopteran lineages is discussed. Furthermore, the data are used to postulate the individual neuropeptide sequences that were present at the time of the insect emergence more than 400 million years ago. The data confirm that the extent of sequence conservation across Polyneoptera is remarkably different between the different neuropeptides. Furthermore, the average evolutionary distance for the single-copy neuropeptides differs significantly between the polyneopteran orders. Nonetheless, the single-copy neuropeptide precursors of the Polyneoptera show a relatively high degree of sequence conservation. Basic features of these precursors in this very heterogeneous insect group are explained here in detail for the first time.

Topics: Amino Acid Sequence; Animals; Drosophila Proteins; Evolution, Molecular; Insect Hormones; Insect Proteins; Insecta; Neoptera; Neuropeptides; Oligopeptides; Phylogeny; Protein Precursors

The mosquito Anopheles gambiae is an important vector for malaria, which is one of the most serious human parasitic diseases in the world, causing up to 2.7 million deaths yearly. To contribute to our understanding of A. gambiae and to the transmission of malaria, we have now cloned four evolutionarily related G protein-coupled receptors (GPCRs) from this mosquito and expressed them in Chinese hamster ovary cells. After screening of a library of thirty-three insect or other invertebrate neuropeptides and eight biogenic amines, we could identify (de-orphanize) three of these GPCRs as: an adipokinetic hormone (AKH) receptor (EC(50) for A. gambiae AKH, 3x10(-9)M), a corazonin receptor (EC(50) for A. gambiae corazonin, 4x10(-9)M), and a crustacean cardioactive peptide (CCAP) receptor (EC(50) for A. gambiae CCAP, 1x10(-9)M). The fourth GPCR remained an orphan, although its close evolutionary relationship to the A. gambiae and other insect AKH receptors suggested that it is a receptor for an AKH-like peptide. This is the first published report on evolutionarily related AKH, corazonin, and CCAP receptors in mosquitoes.

Topics: Amino Acid Sequence; Animals; Anopheles; CHO Cells; Cloning, Molecular; Cricetinae; Cricetulus; Evolution, Molecular; Gene Order; Insect Hormones; Insect Proteins; Insect Vectors; Malaria; Molecular Sequence Data; Neuropeptides; Oligopeptides; Phylogeny; Pyrrolidonecarboxylic Acid; Receptors, G-Protein-Coupled; Receptors, Neuropeptide

Changes in the frequency of cardiac pulsations have been monitored in the decapitated body of adult P. americana before and 5 h after the injections of [Arg(7)]-corazonin and CCAP, using newly invented touch-free, noninvasive optocardiographic methods. Relatively large dosages of these peptides (10(-6) M concentrations in the body) had no effect on the rate of the heartbeat beyond the Ringer control limits. It has been concluded, therefore, that Corazonin and CCAP, which are currently cited in the literature as "the most potent cardiostimulating peptides" in insects, have no effect on the physiological regulation of cardiac functions in the living body.

Topics: Animals; Electrocardiography; Female; Heart Rate; Insect Proteins; Male; Neuropeptides; Optics and Photonics; Periplaneta; Time Factors