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Abou El Asrar R, Cools D, Vanden Broeck J. Role of peptide hormones in insect gut physiology. CURRENT OPINION IN INSECT SCIENCE 2020; 41:71-78. [PMID: 32814267 DOI: 10.1016/j.cois.2020.07.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 05/09/2020] [Accepted: 07/22/2020] [Indexed: 06/11/2023]
Abstract
Nutrient uptake and digestion are essential for optimal growth and development. In insects, these processes are regulated by the gut-brain axis, which is a neurohumoral communication system for maintaining gut homeostasis. The insect gut is a complex organ consisting of three distinct structures, denominated foregut, midgut and hindgut, each with their specific specializations. These specializations are tightly regulated by the interplay of several neuropeptides: a versatile group of signalling molecules involved in a multitude of processes including gut physiology. Neuropeptides take part in the regulation of gut processes ranging from digestive enzyme release to muscle activity and satiety. Some neuropeptide mimetics are a promising strategy for ecological pest management. This review focuses on a selection of neuropeptides that are well-known for their role in gut physiology, and neuropeptides for which the mode of action is yet to be unravelled.
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Affiliation(s)
- Rania Abou El Asrar
- KU Leuven, Department of Biology, Research Group of Molecular Developmental Physiology and Signal Transduction, Naamsestraat 59 Box 2465, 3000 Leuven, Belgium
| | - Dorien Cools
- KU Leuven, Department of Biology, Research Group of Molecular Developmental Physiology and Signal Transduction, Naamsestraat 59 Box 2465, 3000 Leuven, Belgium
| | - Jozef Vanden Broeck
- KU Leuven, Department of Biology, Research Group of Molecular Developmental Physiology and Signal Transduction, Naamsestraat 59 Box 2465, 3000 Leuven, Belgium.
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Zhang F, Wang J, Thakur K, Hu F, Zhang JG, Jiang XF, An SH, Jiang H, Jiang L, Wei ZJ. Isolation functional characterization of allatotropin receptor from the cotton bollworm, Helicoverpa armigera. Peptides 2019; 122:169874. [PMID: 29198647 DOI: 10.1016/j.peptides.2017.11.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Revised: 11/24/2017] [Accepted: 11/27/2017] [Indexed: 12/31/2022]
Abstract
Insect allatotropin (AT) plays multi-functions including regulation of juvenile hormone synthesis, growth, development and reproduction. In the present study, the full-length cDNA encoding the AT receptor was cloned from the brain of Helicoverpa armigera (Helar-ATR). The ORF of Helar-ATR exhibited the characteristic seven transmembrane domains of the G protein-coupled receptor (GPCR) and was close to the ATR of Manduca sexta in the phylogenetic tree. The Helar-ATR expressed in vertebrate cell lines can be activated by Helar-AT and each Helar-ATL in a dose-responsive manner, in the following order: Helar-ATLI > Helar-ATLII > Helar-AT > Helar-ATLIII. Helar-ATLI and Helar-ATLII represented the functional ligands to Helar-ATR in vitro, while Helar-AT and Helar-ATLIII behaved as partial agonists. The in vitro functional analysis suggested that the Helar-ATR signal was mainly coupled with elevated levels of Ca2+ and independent of cAMP levels. Helar-ATR mRNA in larvae showed the highest level in the brain, followed by the thorax ganglion, abdomen ganglion, fat body and midgut. Helar-ATR mRNA levels in the complex of the brain-thoracic-abdomen ganglion on the 2nd day of the larval stage and during later pupal stages were observed to be relatively higher than in the wandering and early pupal stages.
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Affiliation(s)
- Fang Zhang
- School of Food Science and Engineering, Hefei University of Technology, Hefei 230009, China
| | - Jun Wang
- School of Food Science and Engineering, Hefei University of Technology, Hefei 230009, China
| | - Kiran Thakur
- School of Food Science and Engineering, Hefei University of Technology, Hefei 230009, China
| | - Fei Hu
- School of Food Science and Engineering, Hefei University of Technology, Hefei 230009, China
| | - Jian-Guo Zhang
- School of Food Science and Engineering, Hefei University of Technology, Hefei 230009, China
| | - Xing-Fu Jiang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Shi-Hen An
- College of Plant Protection, Henan Agricultural University, Zhengzhou 450002, China
| | - Hongbo Jiang
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing 400715, China
| | - Li Jiang
- School of Food Science and Engineering, Hefei University of Technology, Hefei 230009, China.
| | - Zhao-Jun Wei
- School of Food Science and Engineering, Hefei University of Technology, Hefei 230009, China.
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The pharmacological and functional characterization of the serotonergic system in Anopheles gambiae and Aedes aegypti: influences on flight and blood-feeding behavior. Sci Rep 2019; 9:4421. [PMID: 30872615 PMCID: PMC6418270 DOI: 10.1038/s41598-019-38806-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 01/09/2019] [Indexed: 12/28/2022] Open
Abstract
Aedes aegypti and Anopheles gambiae harbor the causative agents of diseases such as dengue fever and malaria, afflicting human morbidity and mortality worldwide. Given the worldwide emergence of resistance to insecticides, the current mainstay for vector control, identification of alternative modes of action for future insecticides is paramount. The serotonergic (5-HT) system has been documented to impact physiological mechanisms involved in disease transmission, suggesting its potential as a new mode of action target for future insecticide development. Target 5-HT receptors were cloned and expressed in the HEK293 cell line for functional and pharmacological characterization. Manipulation of the 5-HT system through microinjection of compounds suggests its involvement in the modulation of flight performance and blood-feeding behavior. By attenuating these two determinants of vectorial capacity, transmission and burden of disease could effectively be reduced. Considering these positive global health implications, the 5-HT system is a compelling target for the novel insecticide pipeline.
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Bednár B, Roller L, Čižmár D, Mitrová D, Žitňan D. Developmental and sex-specific differences in expression of neuropeptides derived from allatotropin gene in the silkmoth Bombyx mori. Cell Tissue Res 2017; 368:259-275. [PMID: 28091775 DOI: 10.1007/s00441-016-2556-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 12/06/2016] [Indexed: 01/01/2023]
Abstract
Allatotropin (AT) and related neuropeptides are widespread bioactive molecules that regulate development, food intake and muscle contractions in insects and other invertebrates. In moths, alternative splicing of the at gene generates three mRNA precursors encoding AT with different combinations of three structurally similar AT-like peptides (ATLI-III). We used in situ hybridization and immunohistochemistry to map the differential expression of these transcripts during the postembryonic development of Bombyx mori. Transcript encoding AT alone was expressed in numerous neurons of the central nervous system and frontal ganglion, whereas transcripts encoding AT with ATLs were produced by smaller specific subgroups of neurons in larval stages. Metamorphosis was associated with considerable developmental changes and sex-specific differences in the expression of all transcripts. The most notable was the appearance of AT/ATL transcripts (1) in the brain lateral neurosecretory cells producing prothoracicotropic hormone; (2) in the male-specific cluster of about 20 neurons in the posterior region of the terminal abdominal ganglion; (3) in the female-specific medial neurons in the abdominal ganglia AG2-7. Immunohistochemical staining showed that these neurons produced a mixture of various neuropeptides and innervated diverse peripheral organs. Our data suggest that AT/ATL neuropeptides are involved in multiple stage- and sex-specific functions during the development of B. mori.
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Affiliation(s)
- Branislav Bednár
- Institute of Zoology, Slovak Academy of Sciences, Dúbravská cesta 9, 845 06, Bratislava, Slovakia
| | - Ladislav Roller
- Institute of Zoology, Slovak Academy of Sciences, Dúbravská cesta 9, 845 06, Bratislava, Slovakia
| | - Daniel Čižmár
- Institute of Zoology, Slovak Academy of Sciences, Dúbravská cesta 9, 845 06, Bratislava, Slovakia
| | - Diana Mitrová
- Institute of Zoology, Slovak Academy of Sciences, Dúbravská cesta 9, 845 06, Bratislava, Slovakia
| | - Dušan Žitňan
- Institute of Zoology, Slovak Academy of Sciences, Dúbravská cesta 9, 845 06, Bratislava, Slovakia.
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Petrova A, Moffett DF. Comprehensive Immunolocalization Studies of a Putative Serotonin Receptor from the Alimentary Canal of Aedes aegypti Larvae Suggest Its Diverse Roles in Digestion and Homeostasis. PLoS One 2016; 11:e0146587. [PMID: 26808995 PMCID: PMC4726579 DOI: 10.1371/journal.pone.0146587] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Accepted: 12/18/2015] [Indexed: 11/17/2022] Open
Abstract
Serotonin regulates key processes including digestion and homeostasis in insects. Serotonin effects are mediated by serotonin receptors that transduce information through initiation of second messenger signaling pathways. Lack of information on serotonin receptors associated with the alimentary canal impedes the understanding of the serotonergic role in insect physiology. To address this void, the present study has cloned and identified a putative serotonin receptor (hereafter AaSeR-1) from the alimentary canal of Aedes aegypti (yellow fever mosquito) larvae. In addition to in-silico analyses of AaSeR-1 primary sequence, immunohistochemical investigations were carried out to elucidate receptor expression patterns. Specific AaSeR-1 immunofluorescence was detected in the caeca, the mid- and hindgut, including the Malpighian tubules. These findings point out not only receptor ubiquitous nature but also its involvement in regulation of different stages of nutrient processing and homeostasis. Furthermore, AaSeR-1 may mediate an array of effects through its differential expression at various cell compartments. While AaSeR-1 specific immunofluorescence was depicted in the nucleus and nucleolus of principal cells of the anterior midgut, in the posterior, analyses suggest receptor association with the plasma membrane of both principal and regenerative cells. In addition, AaSeR-1 immunofluorescence was also found in some enteroendocrine cells and in both circular and longitudinal muscles that innervate the alimentary canal. Overall, immunohistochemical analyses of AaSeR-1 expression indicate that this receptor exercises multiple roles in digestion- and homeostasis-related mechanisms.
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Affiliation(s)
- Adelina Petrova
- School of Biological Sciences, Washington State University, Pullman, WA, United States of America
| | - David Franklin Moffett
- School of Biological Sciences, Washington State University, Pullman, WA, United States of America
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Verlinden H, Gijbels M, Lismont E, Lenaerts C, Vanden Broeck J, Marchal E. The pleiotropic allatoregulatory neuropeptides and their receptors: A mini-review. JOURNAL OF INSECT PHYSIOLOGY 2015; 80:2-14. [PMID: 25982521 DOI: 10.1016/j.jinsphys.2015.04.004] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 04/17/2015] [Accepted: 04/20/2015] [Indexed: 06/04/2023]
Abstract
Juvenile hormones (JH) are highly pleiotropic insect hormones essential for post-embryonic development. The circulating JH titer in the hemolymph of insects is influenced by enzymatic degradation, binding to JH carrier proteins, uptake and storage in target organs, but evidently also by rates of production at its site of synthesis, the corpora allata (CA). The multiple processes in which JH is involved alongside the critical significance of JH in insect development emphasize the importance for elucidating the control of JH production. Production of JH in CA cells is regulated by different factors: by neurotransmitters, such as dopamine and glutamate, but also by allatoregulatory neuropeptides originating from the brain and axonally transported to the CA where they bind to their G protein-coupled receptors (GPCRs). Different classes of allatoregulatory peptides exist which have other functions aside from acting as influencers of JH production. These pleiotropic neuropeptides regulate different processes in different insect orders. In this mini-review, we will give an overview of allatotropins and allatostatins, and their recently characterized GPCRs with a view to better understand their modes of action and different action sites.
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Affiliation(s)
- Heleen Verlinden
- Research Group of Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59, 3000 Leuven, Belgium.
| | - Marijke Gijbels
- Research Group of Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59, 3000 Leuven, Belgium.
| | - Els Lismont
- Research Group of Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59, 3000 Leuven, Belgium.
| | - Cynthia Lenaerts
- Research Group of Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59, 3000 Leuven, Belgium.
| | - Jozef Vanden Broeck
- Research Group of Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59, 3000 Leuven, Belgium.
| | - Elisabeth Marchal
- Research Group of Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59, 3000 Leuven, Belgium.
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Khornchatri K, Kornthong N, Saetan J, Tinikul Y, Chotwiwatthanakun C, Cummins SF, Hanna PJ, Sobhon P. Distribution of serotonin and dopamine in the central nervous system of the female mud crab, Scylla olivacea (Herbst). Acta Histochem 2015; 117:196-204. [PMID: 25618422 DOI: 10.1016/j.acthis.2014.12.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 12/12/2014] [Accepted: 12/12/2014] [Indexed: 01/13/2023]
Abstract
In crustaceans serotonin (5-HT) and dopamine (DA) are neurotransmitters that play roles in the modulation of numerous physiological functions, including reproduction. However, in the mud crab, Scylla olivacea, the distributions of 5-HT and DA in the CNS have not yet been investigated. The aim of our study was to map the distributions of these two neurotransmitters in the central nervous system (CNS) of the female of this crab during the late stage of ovarian development. We found 5-HT immunoreactivity (-ir) and DA-ir in many parts of the CNS, including the eyestalk, brain, and thoracic ganglia. In the eyestalk, 5-HT-ir was localized in the medulla terminalis (MT), hemi-ellipsoid body (HB), and protocerebral tract (PT), whereas DA-ir was present in neuronal cluster 1, the LG neuropils, and PT. In the brain, 5-HT-ir and DA-ir were detected in cells and fibers of neuronal clusters 6, 7, 8, 9, 10, 11, 14, and 15. In the ventral nerve cord, 5-HT-ir was present in neurons of the abdominal ganglia, whereas DA was only present in fibers. These spatial distributions of 5-HT and DA suggest that they may be involved in the neuromodulation of important physiological functions, including ovarian maturation, as shown in other non-crab decapods.
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Masood M, Orchard I. Molecular characterization and possible biological roles of allatotropin in Rhodnius prolixus. Peptides 2014; 53:159-71. [PMID: 24177575 DOI: 10.1016/j.peptides.2013.10.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2013] [Revised: 10/16/2013] [Accepted: 10/16/2013] [Indexed: 11/28/2022]
Abstract
Allatotropins (ATs) are a family of neuropeptides that have been shown to stimulate the biosynthesis of juvenile hormone in certain insect species, and to have stimulatory activity on some visceral muscles. Here, we have examined the AT in Rhodnius prolixus. Molecular analysis revealed a cDNA fragment of 973 bp encoding one mature amidated AT (Rhopr-AT) with transcript levels observed in the central nervous system (CNS) and pool of fat body, trachea and associated peripheral nerves. AT-like immunoreactive neurons were found throughout the CNS and AT-like immunoreactive processes were present on some peripheral tissues. Bioassays based upon changes in hindgut and dorsal vessel contractions failed to demonstrate any myotropic effects of Rhopr-AT on these tissues; however Rhopr-AT stimulated contractions of muscles surrounding the salivary glands and secretion of saliva, as judged by the reduction in content of the cherry red saliva from the salivary glands. Serotonin stimulated an increase in peristaltic contractions of the gland though no secretion was observed. Co-application of Rhopr-AT and serotonin resulted in a more rapid secretion than either chemical alone.
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Affiliation(s)
- Maryam Masood
- Department of Biology, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada.
| | - Ian Orchard
- Department of Biology, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada.
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Wang C, Zhang J, Tobe SS, Bendena WG. Defining the contribution of select neuropeptides and their receptors in regulating sesquiterpenoid biosynthesis by Drosophila melanogaster ring gland/corpus allatum through RNAi analysis. Gen Comp Endocrinol 2012; 176:347-53. [PMID: 22245290 DOI: 10.1016/j.ygcen.2011.12.039] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Revised: 12/23/2011] [Accepted: 12/24/2011] [Indexed: 10/14/2022]
Abstract
The larval ring gland and adult corpus allatum (CA) of Drosophila melanogaster produce at least three sesquiterpenoid products: methyl farnesoate (MF), juvenile hormone III (JHIII), and JHIII bisepoxide (JHB(3)). Our understanding of neuropeptide regulation of sesquiterpenoid biosynthesis in D. melanogaster has been hampered by uncertainty over the biosynthetic pathway and the sites of action of regulators. As an approach to defining the neuropeptide regulators, we have used in vivo gene-specific silencing (RNAi). D. melanogaster strains containing an inducible UAS-RNAi construct made to either PheGlyLeu-NH(2)-allatostatin (FGLa/AST) and its cognate receptors Dar-1 and Dar-2 or PISCF-allatostatin (PISCF/AST) or its cognate receptors Drostar-1 or Drostar-2 were expressed in vivo. MF, JHIII and JHB(3) production was measured in ring glands of 3rd instars or corpora allata (CA) of adult females using the radiochemical assay. Reduction in FGLa/AST and Dar-1 or Dar-2 mRNA levels had no effect on MF, JHIII, or JHB(3) production in larvae or adults. Inhibition of Drostar-1 expression resulted in a significant decrease in MF and JHB(3) production in 3rd instars with little effect on JHIII biosynthesis. In contrast, inhibition of Drostar-1 in adult females led to a significant increase in MF and JHIII production. Inhibition of Drostar-2 also reduced MF biosynthesis in 3rd instars. In adults, inhibition of Drostar-2 led to a significant increase in MF and JHIII production but showed no effect on JHB(3). PISCF/AST had no effect on sesquiterpenoid biosynthesis when incubated with 3rd instar ring glands but was stimulatory when incubated with adult glands. Inhibition of short neuropeptide F (sNPF) expression by RNAi or application of sNPF to ring glands had no effect on MF, JHIII, or JHB3 biosynthesis in larvae or adults. Reduction in the neuropeptide Y receptor (NepYr) or neuropeptide F receptor (NPF-R) inhibited JHIII and JHB(3) production in 3rd instars but only reduction in NepYr resulted in JHB(3) reduction in adults.
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Affiliation(s)
- Christine Wang
- Department of Biology, Queen's University, Kingston, ON, Canada K7L 3N6
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Bendena WG, Tobe SS. Families of allatoregulator sequences: a 2011 perspective1This review is part of a virtual symposium on recent advances in understanding a variety of complex regulatory processes in insect physiology and endocrinology, including development, metabolism, cold hardiness, food intake and digestion, and diuresis, through the use of omics technologies in the postgenomic era. CAN J ZOOL 2012. [DOI: 10.1139/z2012-012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Three different peptide families have been named “allatostatins” (ASTs), based on their initial purifications which were based on their ability to inhibit juvenile hormone (JH) biosynthesis. These include (i) a family of peptides that have a consensus C-terminal sequence Y/FXFGL-NH2; (ii) a family of peptides with a conserved C-terminal sequence W(X)6W-NH2; and(iii) a family of peptides with C-terminal sequence PISCF, some of which are C-terminally-amidated. Each allatostatin family has functions distinct and apart from the inhibition of JH biosynthesis. A peptide family known as the “allatotropins” serve to stimulate JH biosynthesis. This family of peptides also has been proven to exert multiple effects dependent on the species in question. Genome and peptidome projects are uncovering new members of these families and it is clear that these structures are not just confined to Insecta but are found in a range of invertebrates. The receptors for these neuropeptides have been identified and tested experimentally for specific ligand binding. The Y/FXFGLa-ASTs exert their action through galanin-like receptors, W(X)6Wa-ASTs through a sex peptide-binding receptor, and PISCF-ASTs through somatostatin-like receptors. These receptors are conserved through evolutionary time and are being identified in numerous invertebrates by way of genome projects.
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Affiliation(s)
- William G. Bendena
- Department of Biology and Centre for Neurosciences, Queen’s University, Kingston, ON K7L 3N6, Canada
| | - Stephen S. Tobe
- Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
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Horodyski FM, Verlinden H, Filkin N, Vandersmissen HP, Fleury C, Reynolds SE, Kai ZP, Broeck JV. Isolation and functional characterization of an allatotropin receptor from Manduca sexta. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2011; 41:804-814. [PMID: 21699978 DOI: 10.1016/j.ibmb.2011.06.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Revised: 06/01/2011] [Accepted: 06/06/2011] [Indexed: 05/31/2023]
Abstract
Manduca sexta allatotropin (Manse-AT) is a multifunctional neuropeptide whose actions include the stimulation of juvenile hormone biosynthesis, myotropic stimulation, cardioacceleratory functions, and inhibition of active ion transport. Manse-AT is a member of a structurally related peptide family that is widely found in insects and also in other invertebrates. Its precise role depends on the insect species and developmental stage. In some lepidopteran insects including M. sexta, structurally-related AT-like (ATL) peptides can be derived from alternatively spliced mRNAs transcribed from the AT gene. We have isolated a cDNA for an AT receptor (ATR) from M. sexta by a PCR-based approach using the sequence of the ATR from Bombyx mori. The sequence of the M. sexta ATR is similar to several G protein-coupled receptors from other insect species and to the mammalian orexin receptor. We demonstrate that the M. sexta ATR expressed in vertebrate cell lines is activated in a dose-responsive manner by Manse-AT and each Manse-ATL peptide in the rank order ATL-I > ATL-II > ATL-III > AT, and functional analysis in multiple cell lines suggest that the receptor is coupled through elevated levels of Ca(2+) and cAMP. In feeding larvae, Manse-ATR mRNA is present at highest levels in the Malpighian tubules, followed by the midgut, hindgut, testes, and corpora allata, consistent with its action on multiple target tissues. In the adult corpora cardiaca--corpora allata complex, Manse-ATR mRNA is present at relatively low levels in both sexes.
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Affiliation(s)
- Frank M Horodyski
- Department of Biomedical Sciences, College of Osteopathic Medicine, Ohio University, Athens, OH, USA.
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12
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Zhao XC, Feng HQ, Wu B, Wu XF, Liu ZF, Wu KM, McNeil JN. Does the onset of sexual maturation terminate the expression of migratory behaviour in moths? A study of the oriental armyworm, Mythimna separata. JOURNAL OF INSECT PHYSIOLOGY 2009; 55:1039-1043. [PMID: 19643107 DOI: 10.1016/j.jinsphys.2009.07.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2009] [Revised: 07/19/2009] [Accepted: 07/20/2009] [Indexed: 05/28/2023]
Abstract
It is generally accepted that in most insects adults are sexually immature when they initiate migration and that migratory behaviour terminates with the onset of sexual maturation. However, a few studies examining the mating status of field collected moths have suggested that sexually mature individuals may continue migrating, but in these cases it was impossible to completely eliminate the possibility that the mated females captured came from local, non-migrant populations. In this study we examined the ovarian development of Mythimna separata females captured using a vertical pointing searchlight trap on Beihuang Island in the Bohai Gulf, China, a site >40km from land. Moths were collected from May to October from 2003 to 2008 in order to test the hypothesis that the onset of sexual maturation resulted in the termination of migratory behaviour. While females at the end of the summer had little ovarian development and were unmated, a significant proportion of those migrating northward in the early summer had developed ovaries and often had at least one spermatophore. Given that theses insects were captured while flying up to 500m above sea level, at a site with no local populations, the findings would not support the hypothesis and suggest that both ovarian development and mating may occur during migration.
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Affiliation(s)
- Xin Cheng Zhao
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, PR China
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13
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Siju KP, Hansson BS, Ignell R. Immunocytochemical localization of serotonin in the central and peripheral chemosensory system of mosquitoes. ARTHROPOD STRUCTURE & DEVELOPMENT 2008; 37:248-59. [PMID: 18424232 DOI: 10.1016/j.asd.2007.12.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2007] [Revised: 12/18/2007] [Accepted: 12/22/2007] [Indexed: 05/11/2023]
Abstract
Female mosquitoes depend on blood to complete their reproductive cycle and rely mainly on chemosensory systems to obtain blood meals. An immunocytochemical analysis reveals a number of serotonin-immunoreactive neurons that innervate the chemosensory systems, suggesting a potential role of serotonin in modulating chemosensory processes. In the primary olfactory system, we identify a single ipsilateral centrifugal neuron with arborizations in higher brain centers; the varicosities of this neuron display volumetric changes in response to both blood feeding and during a circadian rhythm. Six to eight pairs of serotonin-immunoreactive neurons are identified in the primary gustatory neuropil, including the subesophageal ganglion and tritocerebrum. The peripheral chemosensory organs, i.e. the antenna, the maxillary palp and the labium, are described as having extensive serotonergic neurohemal plexi. In addition, we describe the presence of serotonin-immunoreactive fibers in the mechanosensory Johnston's organ. Taking these results together, we discuss the potential role of serotonin as a neuromodulator in the chemosensory system of disease vector mosquitoes.
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Affiliation(s)
- K P Siju
- Division of Chemical Ecology, Department of Plant Protection Biology, SLU, Box 44, 230 53 Alnarp, Sweden
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Bede JC, McNeil JN, Tobe SS. The role of neuropeptides in caterpillar nutritional ecology. Peptides 2007; 28:185-96. [PMID: 17161504 DOI: 10.1016/j.peptides.2006.08.030] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2006] [Revised: 08/10/2006] [Accepted: 08/10/2006] [Indexed: 11/17/2022]
Abstract
Plant diet strongly impacts the fitness of insect herbivores. Immediately, we think of plant defensive compounds that may act as feeding deterrents or toxins. We are, probably, less aware that plants also influence insect growth and fecundity through their nutritional quality. However, most herbivores respond to their environment and select the diet which optimizes their growth and development. This regulation of nutritional balance may occur on many levels: through selecting and ingesting appropriate plant tissue and nutrient digestion, absorption and utilization. Here, we review evidence of how nutritional requirements, particularly leaf protein to digestible carbohydrate ratios, affect caterpillar herbivores. We propose a model where midgut endocrine cells assess and integrate hemolymph nutritional status and gut content and release peptides which influence digestive processes. Understanding the effects of diet on the insect herbivore is essential for the rational design and implementation of sustainable pest management practices.
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Affiliation(s)
- Jacqueline C Bede
- Department of Plant Science, McGill University, Ste-Anne-de-Bellevue, Que., Canada H9X 3V9.
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15
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Rachinsky A, Mizoguchi A, Srinivasan A, Ramaswamy SB. Allatotropin-like peptide in Heliothis virescens: tissue localization and quantification. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2006; 62:11-25. [PMID: 16612808 DOI: 10.1002/arch.20117] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The mating-induced increase in juvenile hormone (JH) biosynthesis in Heliothis virescens females may be stimulated by production and/or release of stimulatory neuropeptides such as allatotropins (AT). Although there is evidence that H. virescens allatotropin may be structurally related to Manduca sexta allatotropin (Manse-AT), little is known of its occurrence and distribution in H. virescens. An enzyme-linked immunosorbent assay (ELISA) using a monoclonal antibody against Manse-AT was used to quantify concentrations of Manse-AT immunoreactivity in tissue extracts of H. virescens. In mated females, the highest concentrations of Manse-AT-like material occurred in the brain. The ventral nervous system and the accessory glands also contained considerable amounts of Manse-AT-like material, whereas concentrations were very low in ovaries, fat body, and flight muscle. The Manse-AT antibody was used for whole-mount immunocytochemistry to localize Manse-AT-immunoreactivity in the central nervous system. Several groups of Manse-AT-immunoreactive cells were discovered in the brain, subesophageal ganglion, and thoracic and abdominal ganglia of H. virescens females and males. Strong immunoreactivity was detected in axons going through the corpora cardiaca and branching out over the surface of the corpora allata. The presence of Manse-AT-like material in various locations in the central nervous system suggests that these peptides may have other as yet unknown functions. At the posterior margin of the terminal ganglion of males, a group of large immunoreactive cells was observed that was not present in females. Other than that, there were no obvious differences between virgin and mated females or males. The lack of differences in AT distribution in mated and virgin females suggests that mating-induced differences in female JH biosynthesis rates may be caused by changes in cellular response to AT at the level of the CA, rather than by changes in the amounts of AT acting on the CA.
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Affiliation(s)
- Anna Rachinsky
- Department of Entomology, Kansas State University, Manhattan, Kansas, USA.
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Yin H, Zhang TY, Xu WH. Structural organization and expression analysis of the cDNA encoding allatotropin in the cotton bollworm, Helicoverpa armigera. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2005; 60:71-83. [PMID: 16175534 DOI: 10.1002/arch.20082] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The cDNA encoding allatotropin (AT), which stimulates juvenile hormone (JH) biosynthesis by the adult corpora allata (CA) of Lepidoptera, was cloned from Helicoverpa armigera (Har). Har-AT cDNA encodes a 135-amino acid polypeptide precursor containing a 13-amino acid AT sequence identical to Manduca sexta AT (Mas-AT). Three other H. armigera AT cDNAs encoding 172, 213, and 246 amino acids were also cloned. The four isoforms were produced by alternative splicing and termed Har-AT1, -AT2, -AT3, and -AT4, respectively. The basic organization of the Har-AT1 polypeptide precursor is similar to that of known ATs from other Lepidoptera with 80-97% identity at amino acid level. From the processing of the polypeptide precursor, three AT-like peptides named Har-ATL-I, -II, and -III were predicted. However, functions of the three AT-like peptides remain to be further elucidated. The evidence of Northern blots showed that a 0.7-kb Har-AT1 transcript is present in the brain and 0.7-kb Har-AT1 and 1.0-kb Har-AT4 transcripts are present in the abdominal ganglion (AG). Using quantitative RT-PCR, Har-AT mRNAs were detectable at much lower levels in other neural tissues, such as suboesophageal ganglion (SG) and thoracic ganglion (TG), but not in non-neural tissue, such as the epidermis, midgut, and fat body. We investigated the spatial and temporal expression of Har-AT gene in the central nervous system, and showed that expression patterns of four isoforms are distinct from each other. The results from immunocytochemistry showed that Har-AT transcript is located in the central nervous system, mainly in the brain and terminal abdominal ganglion (TAG). Thus, the AT gene products, besides affecting JH biosynthesis, might have broad influence on many biological processes in H. armigera.
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Affiliation(s)
- Han Yin
- Department of Molecular and Cell Biology, School of Life Sciences, University of Science and Technology of China, Hefei, China
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17
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Rankin SM, Kwok R, Seymour ML, Shaon Rahman U, Tobe SS. Effects of Manduca allatotropin and localization of Manduca allatotropin-immunoreactive cells in earwigs. Comp Biochem Physiol B Biochem Mol Biol 2005; 142:113-22. [PMID: 16019245 DOI: 10.1016/j.cbpc.2005.06.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2005] [Revised: 06/14/2005] [Accepted: 06/17/2005] [Indexed: 11/23/2022]
Abstract
Manduca sexta allatotropin (Manse-AT) was first isolated on the basis of its ability to stimulate production of juvenile hormone in that insect. We examined whether this neuropeptide affects corpus allatum activity and visceral muscle contraction in adult females of the earwig, Euborellia annulipes. We also assessed the presence of allatotropin-like material in tissues using immunocytochemistry. Manse-AT at 1 nM to 10 muM stimulated juvenile hormone production in vitro by glands of low activity from 2-day virgin females. In glands of high activity from 12-day mated females, 1 and 100 nM allatotropin were effective, but 10 muM was not. Similarly, hindguts of 2-day and 12-day females significantly increased in motility in vitro in response to Manse-AT. A monoclonal antibody to Manse-AT was used to demonstrate allatotropin-like material throughout the nervous system of 2-day, virgin females. Immunoreactivity was most pronounced within varicosities of the corpora cardiaca and perisympathetic organs. No immunofluorescence was observed in gut tissue. Lastly, we showed that extract of retrocerebral complexes also enhanced in vitro hindgut motility from 2-day virgin females, in a dose-dependent manner. These results indicate material similar to M. sexta allatotropin in female earwigs and that such peptides may modulate juvenile hormone biosynthesis and visceral muscle contractions. Sensitivity to the peptides may change with physiological stage.
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Affiliation(s)
- Susan M Rankin
- Department of Biology, Allegheny College, Meadville, PA 16335, USA.
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Homberg U, Brandl C, Clynen E, Schoofs L, Veenstra JA. Mas-allatotropin/Lom-AG-myotropin I immunostaining in the brain of the locust, Schistocerca gregaria. Cell Tissue Res 2004; 318:439-57. [PMID: 15480799 DOI: 10.1007/s00441-004-0913-7] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2003] [Accepted: 05/03/2004] [Indexed: 11/26/2022]
Abstract
Mas-allatotropin (Mas-AT) and Lom-accessory gland-myotropin I (Lom-AG-MTI) are two members of a conserved family of insect neuropeptides, collectively termed allatotropins, which have diverse functions, ranging from stimulation of juvenile hormone secretion to myotropic effects on heart and hindgut. In addition, allatotropins appear to be abundant within the nervous system, suggesting neuroactive roles. To identify neurons in the insect brain suitable for a neurophysiological analysis of the roles of allatotropins, we used antisera against Mas-AT and Lom-AG-MTI to map allatotropin-immunoreactive neurons in the brain of a suitable insect, the locust Schistocerca gregaria. Both antisera revealed basically identical staining patterns throughout the locust brain with more than 12,500 immunostained interneurons per brain hemisphere. Neurosecretory cells were not labeled, and the retrocerebral complex was devoid of immunostaining. Prominent immunoreactive cell types include about 9,600 lamina monopolar neurons, medulla to lobula interneurons, local neurons of the antennal lobe, a giant interneuron of the mushroom body, projection neurons of the glomerular lobe to the mushroom body, and three systems of tangential neurons of the central complex. Several groups of neurons showed colocalization of Mas-AT- and gamma-aminobutyric acid immunostaining. Mass spectrometric analysis identified a peptide with a molecular mass identical to Lom-AG-MTI in all major parts of the locust brain but not in the retrocerebral complex. This study strongly suggests that Lom-AG-MTI is highly abundant in the locust brain, and is likely to play a neuroactive role in many brain circuits including all stages of sensory processing, learning and memory, and higher levels of motor control.
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Affiliation(s)
- Uwe Homberg
- Fachbereich Biologie/Tierphysiologie, Universität Marburg, 35032 Marburg, Germany.
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Elekonich MM, Horodyski FM. Insect allatotropins belong to a family of structurally-related myoactive peptides present in several invertebrate phyla. Peptides 2003; 24:1623-32. [PMID: 14706542 DOI: 10.1016/j.peptides.2003.08.011] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Originally named for its ability to stimulate juvenile hormone production by lepidopteran corpora allata, allatotropin has emerged as a neuropeptide with multiple neural, endocrine and myoactive roles. This paper describes the experimental evidence for allatotropin action, its localization in several species of insects, and its multiple effects on a variety of different tissues that lead to increased hemolymph circulation and gut motility. The overall physiological effects may also include species-specific effects such as the regulation of nutrient absorption, modulation of the circadian cycle and migratory preparedness. In addition, we present evidence suggesting that allatotropins are members of a family of myoactive peptides found in several invertebrate phyla. Finally, we speculate that the myoactive properties of allatotropins are basal and it is likely that the stimulatory action of allatotropins on juvenile hormone synthesis evolved secondarily.
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Affiliation(s)
- Michelle M Elekonich
- Department of Biomedical Sciences and the College of Osteopathic Medicine, Ohio University, Athens, OH 45701, USA
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