Insight into mosquito GnRH-related neuropeptide receptor specificity revealed through analysis of naturally occurring and synthetic analogs of this neuropeptide family

Adipokinetic hormone (AKH), corazonin (CRZ), and the AKH/CRZ-related peptide (ACP) are neuropeptides considered homologous to the vertebrate gonadotropin-releasing hormone (GnRH). All three Aedes aegypti GnRH-related neuropeptide receptors have been characterized and functionally deorphanized. Individually they exhibit high specificity for their native ligands, prompting us to investigate the contribution of ligand structures in conferring receptor specificity for two of these receptors. Here, we designed a series of analogs based on the native ACP sequence and screened them using a heterologous system to identify critical residues required for ACP receptor (ACPR) activation. Analogs lacking the carboxy-terminal amidation, replacing aromatics, as well as truncated analogs were either completely inactive or had very low activities on ACPR. The polar threonine (position 3) and the blocked amino-terminal pyroglutamate are also critical, whereas ACP analogs with alanine substitutions at position 2 (valine), 5 (serine), 6 (arginine), and 7 (aspartate) were less detrimental including the substitution of charged residues. Replacing asparagine (position 9) with an alanine resulted in a 5-fold more active analog. A naturally-occurring ACP analog, with a conserved substitution in position two, was well tolerated yet displayed significantly reduced activity compared to the native mosquito ACP peptide. Chain length contributes to ligand selectivity in this system, since the endogenous octapeptide Aedae-AKH does not activate the ACPR whereas AKH decapeptides show low albeit significant activity. Similarly, we utilized this in vitro heterologous assay approach against an A. aegypti AKH receptor (AKHR-IA) testing carefully selected naturally-occurring AKH analogs from other insects to determine how substitutions of specific residues in the AKH ligand influence AKHR-IA activation. AKH analogs having single substitutions compared to Aedae-AKH revealed position 7 (either serine or asparagine) was well tolerated or had slightly improved activation whereas changes to position 6 (proline) compromised receptor activation by nearly 10-fold. Substitution of position 3 (threonine) or analogs with combinations of substitutions were quite detrimental with a significant decrease in AKHR-IA activation. Collectively, these results advance our understanding of how two GnRH-related systems in A. aegypti sharing the most recent evolutionary origin sustain independence of function and signaling despite their relatively high degree of ligand and receptor homology.York University Librarie

A Calcium Bioluminescence Assay for Functional Analysis of Mosquito (Aedes aegypti) and Tick (Rhipicephalus microplus) G Protein-coupled Receptors

Arthropod hormone receptors are potential targets for novel pesticides as they regulate many essential physiological and behavioral processes. The majority of them belong to the superfamily of G protein-coupled receptors (GPCRs). We have focused on characterizing arthropod kinin receptors from the tick and mosquito. Arthropod kinins are multifunctional neuropeptides with myotropic, diuretic, and neurotransmitter function. Here, a method for systematic analyses of structure-activity relationships of insect kinins on two heterologous kinin receptor-expressing systems is described. We provide important information relevant to the development of biostable kinin analogs with the potential to disrupt the diuretic, myotropic, and/or digestive processes in ticks and mosquitoes

CAPA neuropeptides and their receptor form an anti-diuretic hormone signalling system in the human disease vector, Aedes aegypti

Insect CAPA neuropeptides are homologs of mammalian neuromedin U and are known to influence ion and water balance by regulating the activity of the Malpighian ‘renal’ tubules (MTs). Several diuretic hormones are known to increase primary fluid and ion secretion by insect MTs and, in adult female mosquitoes, a calcitonin-related peptide (DH31) called mosquito natriuretic peptide, increases sodium secretion to compensate for the excess salt load acquired during blood-feeding. An endogenous mosquito anti-diuretic hormone was recently described, having potent inhibitory activity against select diuretic hormones, including DH31. Herein, we functionally deorphanized, both in vitro and in vivo, a mosquito anti-diuretic hormone receptor (AedaeADHr) with expression analysis indicating highest enrichment in the MTs where it is localized within principal cells. Characterization using a heterologous in vitro system demonstrated the receptor was highly sensitive to mosquito CAPA neuropeptides while in vivo, AedaeADHr knockdown abolished CAPA-induced anti-diuretic control of DH31-stimulated MTs. CAPA neuropeptides are produced within a pair of neurosecretory cells in each of the abdominal ganglia, whose axonal projections innervate the abdominal neurohaemal organs, where these neurohormones are released into circulation. Lastly, pharmacological inhibition of nitric oxide synthase (NOS) and protein kinase G (PKG) signaling eliminated anti-diuretic activity of CAPA, highlighting the role of the second messenger cGMP and NOS/PKG in this anti-diuretic signaling pathway.York University Librarie

Molecular biological studies on neuropeptides of the adipokinetic hormone/red pigment-concentrating hormone family and the neuroparsin family in the arthropod sister groups of insects and crustaceans

Includes abstract.Includes bibliographical references.This study describes the identification of three novel precursor transcripts which includes the adipokinetic hormone (AKH) / red pigment-concentrating hormone (RPCH) and the neuroparsin (NP) from the South African spiny lobster, Jasus lalandii, the RPCH and the RPCH receptor (RPCHR) from the water flea D. pulex and the NP from the southern green stinkbug, Nezara viridula. The study also investigates the localisation and expression profiles of the AKH/RPCH and NP transcripts within crustaceans and insects

Regulatory Needs for the Implementation of Urban Air Mobility In Spain. Innovative Air Mobility Noise Impact in Urban Areas - Regulatory Proposal

SUMARY: 1. EUROPEAN STRATEGIES TO ADDRESS NOISE AND OTHER HARMFUL EFFECTS OF INNOVATIVE AIR MOBILITY. 2. CURRENT REGULATION IN SPAIN. 3. NOTES ON THE REGULATORY NEEDS FOR THE IMPLEMENTATION OF URBAN AIR MOBILITY IN SPAIN. 4. NOISE IMPACT OF INNOVATIVE AIR MOBILITY IN URBAN AREAS. 4.1. Noise emissions from aircraft and their infrastructure (aerodromes) . 4.2. Specific aspects of UAS/UAM noise and future challenges. 4.3. EASA actions. A) Consultation document: Environmental Protection Technical Specification (EPTS) applicable to eVTOL powered by multiple, vertical, non-tilting, evenly distributed rotors I EASA. B) Environmental research - rotorcraft noise I EASA. C) Technical specifications of the vertiports prototype PTS-VPT-DSN. D) Guidelines on noise measurement of unmanned aircraft systems of less than 600 kg operating in the specific category (low and medium risk) - EASA. 4.4. From the generation to the reception (or immission) of noise by the UAS. 4.5. Digital models of the urban environment. 4.6. Digital UAS Models. 4.7. Conclusions

Unique PFK regulatory property from some mosquito vectors of disease, and from Drosophila melanogaster

Effect of F2, 6BP on Aedes aegypti PFK activity. PFK activity was measured at pH = 7.4, 1 mM F6P, 5 mM ATP at several F2, 6BP concentrations (0.01–50 μM). Values are the means ± SEM of three independent experiments. (TIF 466 kb

Functional Elucidation of The Adipokinetic Hormone/Corazonin Related Peptide and Insights into Its Receptor Specificity Using Receptor Chimera in Aedes Aegypti Mosquito

Mosquitoes Aedes aegypti are an essential organism to study as they are significant vectors responsible for transmitting arboviral diseases such as Yellow fever, Dengue and Zika virus. The adipokinetic hormone/corazonin-related peptide (ACP) is an insect neuropeptide that is structurally intermediate between corazonin (CRZ) and adipokinetic hormone (AKH). A well-known function of the AKH signaling system is the mobilization of energy while CRZ was initially described as a cardioacceleratory factor. Contrastingly, the role of ACP and its receptor (ACPr) remains unclear in many insects. Despite the structural similarity and the close evolutionary relationship between ACP and AKH, their signaling systems function independently due to the high selectivity of their corresponding receptors. In light of this knowledge, this thesis sought to advance our understanding of the role of the ACP in A. aegypti by mapping the distribution of ACP in the nervous system, examining the ACPr transcript expression in the abdominal ganglia, assessing the possible involvement of ACP in controlling energy substrate levels, and determining adult survival rate after injection with ACP. Moreover, this study aimed to determine the most critical regions of the ACPr necessary for ligand-binding specificity and discern specific residues critical for functional ligand-binding by singly replacing the three ACPr extracellular loops or critical highly conserved residues and incorporating those from the AKH receptor and testing these ACPr chimeras using a heterologous functional assay. Together, this study gives insight to advance our mechanistic understanding of the broad and critical functions of the ACP signaling system in A. aegypti

Dynamical tunneling in optical cavities

The lifetime of whispering gallery modes in a dielectric cavity with a metallic inclusion is shown to fluctuate by orders of magnitude when size and location of the inclusion are varied. We ascribe these fluctuations to tunneling transitions between resonances quantized in different regions of phase space. This interpretation is confirmed by a comparison of the classical phase space structure with the Husimi distribution of the resonant modes. A model Hamiltonian is introduced that describes the phenomenon and shows that it can be expected in a more general class of systems.Comment: 8 pages LaTeX with 5 postscript figure

First Report of the European Oak Borer, \u3ci\u3eAgrilus Sulcicollis\u3c/i\u3e (Coleoptera: Buprestidae), in the United States

Agrilus sulcicollis Lacordaire was first reported in North America from (Quercus rubra L.), on sticky traps, and also found in insect collections that dated from 1995. After hearing of this discovery in Ontario, unidentified Agrilus specimens that had been collected in Michigan during recent field studies of the emerald ash borer, Agrilus planipennis Fairmaire, were examined. As a result, A. sulcicollis specimens were identified that had been collected in four Michigan counties during 2003 to 2008: Ingham, Oakland, Saint Clair, and Washtenaw. All Michigan specimens had been collected from sticky traps or reared from English oak, Q. robur L. This is the first establishment record of A. sulcicollis in the United States. In addition, A. sulcicollis adults were collected on sticky traps in Monroe and Orleans counties, New York, during surveys in 2009 that targeted A. planipennis. In Europe, A. sulcicollis infests primarily oak. Information is provided on U.S. collection records, U.S. port interception records, and basic life history data of A. sulcicollis