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Kannangara JR, Mirth CK, Warr CG. Regulation of ecdysone production in Drosophila by neuropeptides and peptide hormones. Open Biol 2021; 11:200373. [PMID: 33593157 PMCID: PMC8103234 DOI: 10.1098/rsob.200373] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
In both mammals and insects, steroid hormones play a major role in directing the animal's progression through developmental stages. To maximize fitness outcomes, steroid hormone production is regulated by the environmental conditions experienced by the animal. In insects, the steroid hormone ecdysone mediates transitions between developmental stages and is regulated in response to environmental factors such as nutrition. These environmental signals are communicated to the ecdysone-producing gland via the action of neuropeptide and peptide hormone signalling pathways. While some of these pathways have been well characterized, there is evidence to suggest more signalling pathways than has previously been thought function to control ecdysone production, potentially in response to a greater range of environmental conditions. Here, we review the neuropeptide and peptide hormone signalling pathways known to regulate the production of ecdysone in the model genetic insect Drosophila melanogaster, as well as what is known regarding the environmental signals that trigger these pathways. Areas for future research are highlighted that can further contribute to our overall understanding of the complex orchestration of environmental, physiological and developmental cues that together produce a functioning adult organism.
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Affiliation(s)
- Jade R Kannangara
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia
| | - Christen K Mirth
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia
| | - Coral G Warr
- Tasmanian School of Medicine, University of Tasmania, Hobart, Tasmania 7000, Australia
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VAFOPOULOU XANTHE, STEEL COLING. Prothoracicotropic hormone ofRhodnius prolixus: partial characterization and rhythmic release of neuropeptides related toBombyxPTTH and bombyxin. INVERTEBR REPROD DEV 2002. [DOI: 10.1080/07924259.2002.9652767] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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3
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Sehnal F, Hansen I, Scheller K. The cDNA-structure of the prothoracicotropic hormone (PTTH) of the silkmoth Hyalophora cecropia. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2002; 32:233-237. [PMID: 11755069 DOI: 10.1016/s0965-1748(01)00107-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The structure of the prothoracicotropic neurohormone (PTTH) of the silkmoth Hyalophora cecropia was elucidated at the cDNA level. The identified cDNA of 803 nt, which is over 90% identical with the corresponding part of the Samia cynthia ricini PTTH gene, encodes a preprohormone of 240 amino acids. Presence of proteolytic cleavage sites indicates that the preprohormone is split into a signal peptide, an intercalated peptide (64 residues), and the PTTH monomer (125 residues). Preprohormones of H. cecropia, S. c. ricini, Antheraea pernyi, and Bombyx mori diversified considerably in all these parts, indicating that the evolution of PTTH is unusually fast. Since a similarly rapid, and concerted evolution of the corresponding receptor is unlikely, the PTTH activity probably depends on the conservation of relatively few amino acids allowing proper molecular folding.
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Affiliation(s)
- Frantisek Sehnal
- Institute of Entomology, Academy of Sciences, Ceské Budejovice, Czech Republic.
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Dedos SG, Fugo H, Nagata S, Takamiya M, Kataoka H. Differences between recombinant PTTH and crude brain extracts in cAMP-mediated ecdysteroid secretion from the prothoracic glands of the silkworm, Bombyx mori. JOURNAL OF INSECT PHYSIOLOGY 1999; 45:415-422. [PMID: 12770324 DOI: 10.1016/s0022-1910(98)00140-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The ability of recombinant prothoracicotropic hormone (rPTTH) or crude brain extract (cBRAIN) of Bombyx mori to stimulate ecdysteroid secretion from prothoracic glands (PGs) was investigated throughout the fifth instar and the first day of the pupal stage. Crude brain extracts could stimulate much higher ecdysteroid secretion than rPTTH during a 2h incubation. Recombinant PTTH did not increase the level of glandular cyclic AMP, except on days 4 and 5 of the fifth instar. Glandular cAMP levels were increased by cBRAIN from day 0 until day 5 of the fifth instar with the highest increase on day 3. On this day, rPTTH could not stimulate any increase of ecdysteroid secretion from the PGs during a 30min incubation. On the contrary, PGs incubated with cBRAIN for 30min showed increased secretory activity. Furthermore, on day 3 and in the absence of extracellular Ca(2+), rPTTH did not increase the glandular cAMP levels but cBRAIN did. Recombinant PTTH-stimulated ecdysteroid secretion from day 3 PGs was dependent on extracellular Ca(2+) in a dose-dependent manner. However, cBRAIN could stimulate ecdysteroid secretion even in the absence of extracellular Ca(2+). Taken together, the results of these experiments suggest the presence of a previously unknown cerebral prothoracicotropic factor that can stimulate glandular cAMP levels and ecdysteroid secretion from the PGs of Bombyx mori.
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Affiliation(s)
- S G. Dedos
- Department of Biological Production, Tokyo University of Agriculture and Technology, Fuchu-shi, Tokyo, Japan
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Henrich VC, Rybczynski R, Gilbert LI. Peptide hormones, steroid hormones, and puffs: mechanisms and models in insect development. VITAMINS AND HORMONES 1999; 55:73-125. [PMID: 9949680 DOI: 10.1016/s0083-6729(08)60934-6] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- V C Henrich
- Department of Biology, University of North Carolina, Greensboro 27412-5001, USA
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Mansfield SG, Cammer S, Alexander SC, Muehleisen DP, Gray RS, Tropsha A, Bollenbacher WE. Molecular cloning and characterization of an invertebrate cellular retinoic acid binding protein. Proc Natl Acad Sci U S A 1998; 95:6825-30. [PMID: 9618497 PMCID: PMC22650 DOI: 10.1073/pnas.95.12.6825] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
We have cloned a cDNA and gene from the tobacco hornworm, Manduca sexta, which is related to the vertebrate cellular retinoic acid binding proteins (CRABPs). CRABPs are members of the superfamily of lipid binding proteins (LBPs) and are thought to mediate the effects of retinoic acid (RA) on morphogenesis, differentiation, and homeostasis. This discovery of a Manduca sexta CRABP (msCRABP) demonstrates the presence of a CRABP in invertebrates. Compared with bovine/murine CRABP I, the deduced amino acid sequence of msCRABP is 71% homologous overall and 88% homologous for the ligand binding pocket. The genomic organization of msCRABP is conserved with other CRABP family members and the larger LBP superfamily. Importantly, the promoter region contains a motif that resembles an RA response element characteristic of the promoter region of most CRABPs analyzed. Three-dimensional molecular modeling based on postulated structural homology with bovine/murine CRABP I shows msCRABP has a ligand binding pocket that can accommodate RA. The existence of an invertebrate CRABP has significant evolutionary implications, suggesting CRABPs appeared during the evolution of the LBP superfamily well before vertebrate/invertebrate divergence, instead of much later in evolution in selected vertebrates.
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Affiliation(s)
- S G Mansfield
- Intron LLC, 710 West Main Street, Durham, NC 27701-2801, USA
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Gilbert LI, Song Q, Rybczynski R. Control of ecdysteroidogenesis: activation and inhibition of prothoracic gland activity. INVERTEBRATE NEUROSCIENCE : IN 1997; 3:205-16. [PMID: 9783446 DOI: 10.1007/bf02480376] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The ecdysteroid hormones, mainly 20-hydroxyecdysone (20E), play a pivotal role in insect development by controlling gene expression involved in molting and metamorphosis. In the model insect Manduca sexta the production of ecdysteroids by the prothoracic gland is acutely controlled by a brain neurohormone, prothoracicotropic hormone (PTTH). PTTH initiates a cascade of events that progresses from the influx of Ca2+ and cAMP generation through phosphorylation of the ribosomal protein S6 and S6-dependent protein synthesis, and concludes with an increase in the synthesis and export of ecdysteroids from the gland. Recent studies indicate that S6 phosphorylation probably controls the steroidogenic effect of PTTH by gating the translation of selected mRNAs whose protein products are required for increased ecdysteroid synthesis. Inhibition of S6 phosphorylation prevents an increase in PTTH-stimulated protein synthesis and subsequent ecdysteroid synthesis. Two of the proteins whose translations are specifically stimulated by PTTH have been identified, one being a beta tubulin and the other a heat shock protein 70 family member. Current data suggest that these two proteins could be involved in supporting microtubule-dependent protein synthesis and ecdysone receptor assembly and/or function. Recent data also indicate that the 20E produced by the prothoracic gland feeds back upon the gland by increasing expression and phosphorylation of a specific USP isoform that is a constituent of the functional ecdysone receptor. Changes in the concentration and composition of the ecdysone receptor complex of the prothoracic gland could modulate the gland's potential for ecdysteroid synthesis (e.g. feedback inhibition) by controlling the levels of enzymes or other proteins in the ecdysteroid biosynthetic pathway.
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Affiliation(s)
- L I Gilbert
- Department of Biology, University of North Carolina at Chapel Hill 27599-3280, USA.
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Bollenbacher WE, Gray RS, Whisenton LR, Muehleisen DP, Nogueira BV. Life cycle expression of a bombyxin-like neuropeptide in the tobacco hornworm, Manduca sexta. JOURNAL OF INSECT PHYSIOLOGY 1997; 43:47-53. [PMID: 12769929 DOI: 10.1016/s0022-1910(96)00068-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Immunocytochemistry was used to investigate the developmental expression of the insulin-like neuropeptide bombyxin in the tobacco hornworm, Manduca sexta. A mouse monoclonal antibody raised against a synthetic peptide corresponding to bombyxin's A-chain N-terminus was used to localize a bombyxin-like peptide to a group of cerebral medial neurosecretory cells, the M-NSC IIa(2). Immunostaining was first detected on day 0 of the second larval instar, localized in the M-NSC IIa(2) somata and in the neurohemal organ, the corpora allata (CA). By day 0 of the fourth larval instar, the peptide was present throughout the M-NSC IIa(2) somata, axons, dendritic fields and CA. Between days 7 and 9 of the fifth instar, a dramatic reduction in the dendritic fields and CA staining occurred, suggesting the peptide is released. After day 2 of the pupal period, only M-NSC IIa(2) somata immunostained, a pattern that persisted through day 2 of the adult stage. The specificity of immunostaining was demonstrated by using a synthetic bombyxin peptide to block staining. These developmental data reveal times of potential Manduca bombyxin-like peptide release which should provide insight into the peptide's function.
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Affiliation(s)
- W E. Bollenbacher
- Department of Biology CB# 3280, Coker Hall, 010A University of North Carolina at Chapel Hill, Chapel Hill, U.S.A
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Kim AJ, Cha GH, Kim K, Gilbert LI, Lee CC. Purification and characterization of the prothoracicotropic hormone of Drosophila melanogaster. Proc Natl Acad Sci U S A 1997; 94:1130-5. [PMID: 9037018 PMCID: PMC19756 DOI: 10.1073/pnas.94.4.1130] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/1996] [Accepted: 11/03/1996] [Indexed: 02/03/2023] Open
Abstract
The prothoracicotropic hormone (PTTH) of Drosophila melanogaster is a modulator of ecdysteroid (molting hormone) synthesis and was isolated and characterized from extracts of whole larvae (approximately 4 x 10(5) larvae). The purification protocol included delipidation, salt-extraction, heat treatment, conventional column chromatography, and HPLC, and yielded about 50 microg of pure hormone. Biological activity was followed using a ring gland in vitro assay in which ecdysteroidogenesis by control ring glands as measured by radioimmunoassay was compared with ring gland incubations containing active fractions. The molecular weight of the purified PTTH was 45 kDa and N-terminal amino acid sequence analysis indicated that those analyzed sequences displayed no significant homology with known peptides or peptide hormones, including PTTH from the silkmoth, Bombyx mori. Western blot analysis indicated that the native form of Drosophila PTTH was a single 66-kDa polypeptide with N-linked carbohydrate chains and intrachain disulfide bonds. The purified 45-kDa peptide is the deglycosylated form, a result of glycosidase activity present during preparation of the PTTH extract. The deglycosylated form shows heterogeneity, presumably as a result of varying degrees of deglycosylation at the N terminus.
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Affiliation(s)
- A J Kim
- Department of Molecular Biology, College of Natural Sciences, Seoul National University, Korea
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Gade G. The Explosion of Structural Information on Insect Neuropeptides. FORTSCHRITTE DER CHEMIE ORGANISCHER NATURSTOFFE / PROGRESS IN THE CHEMISTRY OF ORGANIC NATURAL PRODUCTS 1997. [DOI: 10.1007/978-3-7091-6529-4_1] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
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Girgenrath S, Smith WA. Investigation of presumptive mobilization pathways for calcium in the steroidogenic action of big prothoracicotropic hormone. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 1996; 26:455-463. [PMID: 8763164 DOI: 10.1016/0965-1748(96)00001-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Ecdysteroidogenesis in the prothoracic glands of the tobacco hornworm Manduca sexta is stimulated by the cerebral neuropeptide prothoracicotropic hormone (PTTH). PTTH-stimulated cAMP synthesis and ecdysone secretion are dependent on the presence of extracellular calcium, suggesting that PTTH enhances calcium entry into the cytosol. Such entry into the cytosol might involve the opening of a plasma membrane calcium channel, or a mechanism dependent upon prior inositol triphosphate (IP3)-mediated release of intracellularly stored calcium. In pupal prothoracic glands, PTTH does not increase IP3 or other inositol phosphates over-times ranging from seconds up to 30 min, even in the presence of lithium. However, the L-type calcium channel antagonist nitrendipine completely prevents PTTH-stimulated ecdysone synthesis. A 41 kDa G-protein in prothoracic glands is ADP-ribosylated by pertussis toxin. However, PTTH-stimulated ecdysone synthesis is unaffected by prior exposure to pertussis toxin, indicating that the 41 kDa protein is not involved in the acute stimulation of steroidogenesis. By contrast, cholera toxin has a stimulatory effect on ecdysone secretion suggesting the involvement of a Gs-like protein. Based on the absence of PTTH-stimulated inositol phosphate formation in pupal prothoracic glands, it is suggested that calcium mobilization may occur through the opening of a calcium channel, possibly regulated by Gs.
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Affiliation(s)
- S Girgenrath
- Department of Biology, Northeastern University, Boston, MA 02115, USA
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Smith WA, Varghese AH, Healy MS, Lou KJ. Cyclic AMP is a requisite messenger in the action of big PTTH in the prothoracic glands of pupal Manduca sexta. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 1996; 26:161-170. [PMID: 8882659 DOI: 10.1016/0965-1748(95)00078-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Prothoracicotropic hormone (PTTH), a peptide produced by the insect brain, stimulates the prothoracic glands to secrete ecdysteroids. The big form of this peptide (25.5 kDa) has been postulated to act through cyclic AMP in larval Manduca sexta, but the role of the cyclic nucleotide in the action of PTTH in pupal glands has been less clear. Results of the present study indicate that PTTH-stimulated ecdysteroid secretion and protein phosphorylation by glands removed from pupal Manduca sexta are blocked by two inhibitors of cAMP-dependent protein kinase: Rp-cAMPS, an antagonist of cAMP binding to the regulatory subunit of the kinase, and H-89, an inhibitor of the catalytic subunit of the kinase. Further, PTTH stimulates significant accumulation of cAMP in pupal glands, although less than that previously seen in PTTH-stimulated larval glands. Cyclic AMP-dependent protein kinase is found in cytoplasmic and membrane-associated glandular subfractions, as measured by incorporation of [32P]8-N3cAMP into the regulatory subunit of the kinase. PTTH enhances cytoplasmic cAMP content and appears to increase the amount of cAMP bound to a cytoplasmic type II regulatory subunit of cAMP-dependent protein kinase. The results indicate that cAMP plays a requisite role in PTTH action in pupal glands, thus arguing in favor of a uniform mechanism of action for the peptide during Manduca development.
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Affiliation(s)
- W A Smith
- Department of Biology, Northeastern University, Boston, MA 02115, U.S.A
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Hayes GC, Muehleisen DP, Bollenbacher WE, Watson RD. Stimulation of ecdysteroidogenesis by small prothoracicotropic hormone: role of calcium. Mol Cell Endocrinol 1995; 115:105-12. [PMID: 8674858 DOI: 10.1016/0303-7207(95)03679-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Insect prothoracic glands are regulated by neuropeptide prothoracicotropic hormones (PTTH). In Manduca sexta PTTH exists as two size variants, big PTTH (approximately 25.5 kDa) and small PTTH (approximately 7 kDa). Previous studies indicate that both size variants employ cAMP as a second messenger and that stimulation of ecdysteroid secretion by big PTTH is Ca(2+)-dependent. In the present study, experiments were performed to assess the role of Ca2+ in small PTTH-stimulated ecdysteroid secretion by prothoracic glands from fifth instar larvae. Basal ecdysteroid secretion was not affected by Ca2+ channel blockers (verapamil or lanthanum) or by omission of Ca2+ from the incubation medium. Treatment of glands with a Ca2+ ionophore (A23187 or ionomycin) produced a concentration-dependent stimulation of ecdysteroid secretion. Stimulation of ecdysteroid secretion by small PTTH was suppressed (1) by Ca2+ channel blockers and (2) in Ca(2+)-free medium. A cAMP analog (Sp-cAMPS) stimulated ecdysteroid secretion in the presence of a Ca2+ channel blocker (verapamil) and in Ca(2+)-free incubation medium, and ionophore-induced ecdysteroid secretion appeared to be suppressed by a cAMP antagonist (Rp-cAMPS). The combined results indicate that basal ecdysteroid secretion is not dependent on external Ca2+, and suggest that small PTTH-stimulated ecdysteroid secretion is mediated by an influx of Ca2+ that precedes cAMP formation.
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Affiliation(s)
- G C Hayes
- Department of Biology, University of Alabama at Birmingham 35294, USA
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Zitnan D, Kingan TG, Kramer SJ, Beckage NE. Accumulation of neuropeptides in the cerebral neurosecretory system of Manduca sexta larvae parasitized by the braconid wasp Cotesia congregata. J Comp Neurol 1995; 356:83-100. [PMID: 7629311 DOI: 10.1002/cne.903560106] [Citation(s) in RCA: 110] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Fifth instar larvae of Manduca sexta that were parasitized by the braconid wasp Cotesia congregata failed to develop after the parasitoid larvae emerged, and these host larvae lingered for 2-3 weeks in a quiescent, nonfeeding state without initiating a larval molt or metamorphosis. This study was focused on the neuroendocrine changes associated with the host's developmental arrest. Immunohistochemical studies suggested that the host brain neurosecretory cells as well as their axon terminals in the corpora cardiaca-corpora allata complex accumulated multiple neuropeptides. The extent of accumulation in cells and axons increased with time, so that hosts examined 7-14 days after the wasps emerged showed the most intense staining with antibodies against prothoracicotropic hormone, bombyxin, allatotropin, allatostatin, diuretic hormone, eclosion hormone, proctolin, and FMRFamide. Increased levels of prothoracicotropic hormone and FMRFamide-like peptides in the brains of parasitized larvae were confirmed using Western blots and enzyme-linked immunosorbent assay (ELISA), respectively. Starvation of the unparasitized larvae induced some accumulation of the neuropeptides; however, the intensity of staining and number of immunopositive cells and axons were in most cases clearly higher in the parasitized larvae. Our results suggest that accumulation of the neuropeptides is associated with developmental arrest of parasitized larvae. Because a similar developmental arrest occurs in a wide range of parasitized insects, our findings may have relevance for many other species. Moreover, these data illustrate the potential value of using parasitized M. sexta larvae as a model for studying the mechanisms governing the rates of neuropeptide expression, processing, packaging, and release, as well as providing a rich source of neuropeptides, thus facilitating their isolation and characterization.
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Affiliation(s)
- D Zitnan
- Department of Entomology, University of California, Riverside 92521, USA
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Smith WA. Regulation and consequences of cellular changes in the prothoracic glands of Manduca sexta during the last larval instar: a review. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 1995; 30:271-293. [PMID: 7579575 DOI: 10.1002/arch.940300214] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The prothoracic glands of the tobacco hornworm, Manduca sexta, respond to prothoracicotropic hormone (PTTH) by a regulatory pathway involving cAMP, protein phosphorylation, protein synthesis, and enhanced secretion of ecdysteroids including ecdysone and 3-dehydroecdysone. Recent investigations have revealed that PTTH acts by this general mechanism throughout the fifth larval instar, i.e., during the transition from larva to pupa. However, the glands undergo developmental changes in size, steroidogenic capacity, and in elements of the signalling pathway associated with synthesis, degradation, and intracellular action of cAMP. The present review describes such changes, and their possible regulation and consequences, in the general context of endocrine events underlying larval-pupal metamorphosis during the fifth larval stage.
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Affiliation(s)
- W A Smith
- Department of Biology, Northeastern University, Boston, Massachusetts 02115, USA
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DAI JIDA, MIZOGUCHI AKIRA, GILBERT LAWRENCEI. Immunoreactivity of neurosecretory granules in the brain-retrocerebral complex ofManduca sextato heterologous antibodies againstBombyxprothoracicotropic hormone and bombyxin. INVERTEBR REPROD DEV 1994. [DOI: 10.1080/07924259.1994.9672417] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Muehleisen DP, Katahira EJ, Gray RS, Bollenbacher WE. Physical characteristics of the cerebral big prothoracicotropic hormone from Manduca sexta. EXPERIENTIA 1994; 50:159-63. [PMID: 8125174 DOI: 10.1007/bf01984956] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The prothoracicotropic hormones (PTTHs) are cerebral peptides that control insect postembryonic development by stimulating the prothoracic glands to synthesize ecdysteroids. In Manduca sexta, the tobacco hornworm, two classes of PTTH are distinguished by their M(r), small (ca. 7 kDa) and big PTTH (ca. 25-30 kDa). Little is known about the physical nature of the PTTHs and this study takes a first step towards defining characteristics of the Manduca big PTTH. The neurohormone has a Stokes radius of 2.59 nm and a sedimentation coefficient of 2.76 S. Based on these data, an M(r) of 29,443.7 and an f/fo of 1.27 were calculated. Combined, the physical data reveal Manduca big PTTH is an asymmetrical acidic homodimeric peptide with intra- and intermolecular disulfide bonds.
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Affiliation(s)
- D P Muehleisen
- Department of Biology, University of North Carolina at Chapel Hill 27599-3280
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Gray RS, Muehleisen DP, Katahira EJ, Bollenbacher WE. The prothoracicotropic hormone (PTTH) of the commercial silkmoth, Bombyx mori, in the CNS of the tobacco hornworm, Manduca sexta. Peptides 1994; 15:777-82. [PMID: 7984494 DOI: 10.1016/0196-9781(94)90029-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Immunocytochemistry revealed that a Bombyx mori prothoracicotropic hormone (PTTH)-like peptide is expressed by the Manduca sexta big PTTH-producing neurons, the lateral neurosecretory cell group III (L-NSC III). Independent PCR of genomic DNA and a L-NSC III cDNA library yielded products with 99% sequence similarity to the cDNA encoding Bombyx PTTH. This similarity necessitated evaluation of the relationship between Manduca big PTTH and Bombyx PTTH by 1) bioassay of IEF separated Manduca PTTH and 2) direct assessment of Bombyx PTTH biological activity with Manduca prothoracic glands. Together, these studies indicate that Bombyx PTTH and Manduca PTTH are different peptides expressed by the L-NSC III. The possible physiological significance of a Bombyx PTTH-like peptide in Manduca and its coexpression with Manduca big PTTH by the L-NSC III are discussed.
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Affiliation(s)
- R S Gray
- Department of Biology, University of North Carolina at Chapel Hill 27599-3280
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Gray RS, Muehleisen DP, Katahira EJ, Bollenbacher WE. A 28-kDa cerebral neuropeptide from Manduca sexta: relationship to the insect prothoracicotropic hormone. Cell Mol Neurobiol 1993; 13:39-58. [PMID: 8458062 DOI: 10.1007/bf00712988] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
1. A 28-kDa peptide from the brain of the tobacco hornworm, Manduca sexta, was purified via HPLC. The peptide copurified with the insect neurohormone, prothoracicotropic hormone (PTTH), through two HPLC columns. 2. Immunocytochemistry using polyclonal antibodies against the 28-kDa peptide revealed that the peptide was produced in the same protocerebral neurons that produce PTTH. Western blot analysis demonstrated that the 28-kDa peptide and big PTTH are different molecules. 3. A PTTH in vitro bioassay indicated that despite having chromatographic properties similar to those of big PTTH and being produced by the same neurons, the 28-kDa peptide did not have PTTH activity. 4. Amino acid sequence analysis yielded a 27 N-terminal amino acid sequence that had no similarity with known peptides. 5. Immunocytochemical studies revealed that the 28-kDa peptide is present as early as 30% embryonic development and is absent by adult eclosion. This is in contrast to big PTTH, which is expressed throughout the Manduca life cycle. 6. These data suggest that the 28-kDa peptide is another secretory phenotype of the lateral neurosecretory cell group III (L-NSC III) which may have functions distinct from those for big PTTH or may act synergistically with big PTTH.
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Affiliation(s)
- R S Gray
- Department of Biology, University of North Carolina, Chapel Hill 27599-3280
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