Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Insect Hormones”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 127 records · Page 7Linked to original sources
PubMed1996

Insect adipokinetic hormone stimulates inositol phosphate metabolism: roles for both Ins(1,4,5)P3 and Ins(1,3,4,5)P4 in signal transduction?

Adipokinetic hormones (AKHs) control the mobilization of energy reserves from the insect fat body as fuels for flight activity. As a part of our investigations on AKH signal transduction, we demonstrate in this study that the inositol lipid cycle may be involved in the action of AKH-I on fat body of the migratory locust. We show that [3H]inositol is incorporated into fat body phosphoinositides in vitro, whose hydrolysis leads to the formation of the following inositol phosphates (InsPs): Ins(1 and/or 3)P, Ins(4)P, Ins(1,3)P2, Ins(1,4)P2, Ins(3,4)P3, Ins(1,3,4)P3, Ins(1,4,5)P3 and Ins(1,3,4,5)P4. AKH stimulates the formation of these isomers, eliciting an increase in radioactivity of total InsPs already after 1 min. Mass measurements show that Ins(1,4,5)P3 levels are substantially enhanced by AKH, which is indicative of hormonal activation of phospholipase C. In cell-free tissue preparations, Ins(1,4,5)P3 is metabolized through dephosphorylation as well as further phosphorylation. Ins(1,3,4,5)P4 is dephosphorylated primarily to Ins(1,3,4)P3, although the ability for its reconversion to Ins(1,4,5)P3 suggests that in vivo Ins(1,3,4,5)P4 may function as a rapidly mobilizable pool for Ins(1,4,5)P3 generation. Metabolic pathways for the conversion of InsPs to inositol in the locust fat body are proposed.

Animals↗
PubMed1992

A novel DNA-binding motif abuts the zinc finger domain of insect nuclear hormone receptor FTZ-F1 and mouse embryonal long terminal repeat-binding protein.

Fruit fly FTZ-F1, silkworm BmFTZ-F1, and mouse embryonal long terminal repeat-binding protein are members of the nuclear hormone receptor superfamily, which recognizes the same sequence, 5'-PyCAAGGPyCPu-3'. Among these proteins, a 30-amino-acid basic region abutting the C-terminal end of the zinc finger motif, designated the FTZ-F1 box, is conserved. Gel mobility shift competition by various mutant peptides of the DNA-binding region revealed that the FTZ-F1 box as well as the zinc finger motif is involved in the high-affinity binding of FTZ-F1 to its target site. Using a gel mobility shift matrix competition assay, we demonstrated that the FTZ-F1 box governs the recognition of the first three bases, while the zinc finger region recognizes the remaining part of the binding sequence. We also showed that the DNA-binding region of FTZ-F1 recognizes and binds to DNA as a monomer. Occurrence of the FTZ-F1 box sequence in other members of the nuclear hormone receptor superfamily raises the possibility that these receptors constitute a unique subfamily which binds to DNA as a monomer.

Amino Acid Sequence↗
PubMed2005

Segment-specific muscle degeneration is triggered directly by a steroid hormone during insect metamorphosis.

During metamorphosis of the hawkmoth, Manduca sexta, some larval muscles degenerate while others are respecified for new functions. In larvae, accessory planta retractor muscles (APRMs) are present in abdominal segments 1 to 6 (A1 to A6). APRMs serve as proleg retractors in A3 to A6 and body wall muscles in A1 and A2. At pupation, all APRMs degenerate except those in A2 and A3, which are respecified to circulate hemolymph in pupae. The motoneurons that innervate APRMs, the APRs, likewise undergo segment-specific programmed cell death (PCD), as a direct, cell-autonomous response to the prepupal peak of ecdysteroids. The segment-specific patterns of APR and APRM death differ. The present study tested the hypothesis that APRM death is a direct, cell-autonomous response to the prepupal peak of ecdysteroids. Prevention of the prepupal peak prevented APRM degeneration, and replacement of the peak by infusion of 20-hydroxyecdysone restored the correct segment-specific pattern of APRM degeneration. Surgical denervation of APRMs did not perturb their segment-specific degeneration at pupation, indicating that signals from APRs are not required for the muscles' segment-specific responses to ecdysteroids. The possibility that instructive signals originate from APRMs' epidermal attachment points was tested by treating the epidermis with a juvenile hormone analog to prevent pupal development. This manipulation likewise did not alter APRM fate. We conclude that both the muscles and motoneurons in this motor system respond directly and cell-autonomously to prepupal ecdysteroids to produce a segment-specific pattern of PCD that is matched to the functional requirements of the pupal body.

Animals↗
PubMed1986

Insect hypertrehalosemic hormone: isolation and primary structure from Blaberus discoidalis cockroaches.

A new neurohormone was isolated and structurally characterized that increased hemolymph carbohydrate (trehalose) levels in the cockroach, Blaberus discoidalis. The hormone was isolated in high yield by a rapid HPLC procedure. The sequence, pGlu-Val-Asn-Phe-Ser-Pro-Gly-Trp-Gly-Thr-NH2, was suggested from gas-phase Edman degradation of a peptide fragment of the natural peptide after deblocking with pyroglutamate aminopeptidase. The structure was confirmed by synthesis of the suggested sequence. The synthetic peptide had identical chromatographic and biological properties as the natural peptide.

Amino Acid Sequence↗
PubMed2002

Production of the baculovirus-expressed dengue virus glycoprotein NS1 can be improved dramatically with optimised regimes for fed-batch cultures and the addition of the insect moulting hormone, 20-Hydroxyecdysone.

A perennial problem in recombinant protein expression is low yield of the product of interest. A strategy which has been shown to increase the production of baculovirus-expressed proteins is to utilise fed-batch cultures. One disadvantage of this approach is the time-consuming task of optimising the feeding strategy. Previously, a statistical optimisation routine was applied to develop a feeding strategy that increased the yield of beta-Galactosidase (beta-Gal) by 2.4-fold (Biotechnol. Bioeng. 59 (1998) 178). This involves the single addition of nutrient concentrates (amino acids, lipids, glucose and yeastolate ultrafiltrate) into Sf 9 cell cultures grown in SF 900II medium. In this study, it is demonstrated that this optimised fed-batch strategy developed for a high-yielding intracellular product beta-Gal could be applied successfully to a relatively low-yielding glycosylated and secreted product such as the dengue virus glycoprotein NS1. Optimised batch infections yielded 4 microg/ml of NS1 at a peak cell density of 4.2 x 10 (6) cells/ml. In contrast, optimised fed-batch infections exhibited a 3-fold improvement in yield, with 12 microg/ml of NS1 produced at a peak cell density of 11.3 x 10 (6) cells/ml. No further improvements in yield were recorded when the feed volumes were doubled and the peak cell density was increased to 23 x 10 (6) cells/ml, unless the cultures were stimulated by the addition of 4 microg/ml of 20-Hydroxyecdysone (an insect moulting hormone). In this case, the NS1 yield was increased to 20 microg/ml, which was nearly 5-fold higher than optimised batch cultures.

Animals↗
PubMed2002

Coherence between biosynthesis and secretion of insect adipokinetic hormones.

The importance of the process of continuous biosynthesis of locust adipokinetic hormones (AKHs) for the availability of these peptide hormones for release was assessed in vitro by inhibiting this biosynthesis followed by secretory stimulation. Inhibition of the biosynthetic activity for AKHs by brefeldin A caused a considerable inhibition of the AKH release induced by the endogenous crustacean cardioactive peptide (CCAP). After brefeldin A treatment followed by potassium depolarization, CCAP-induced AKH release was completely abolished. In vitro pulse-chase labeling experiments indicated that constitutive secretion from the AKH-producing cells does not occur. It is concluded that AKH secretion involves a regulated release from a relatively small pool of newly formed secretory granules, while older AKH-containing granules appear to be unavailable for release.

Animals↗
PubMed1988

Cyclic AMP: a second messenger of the newly characterized AVP-like insect diuretic hormone, the migratory locust diuretic hormone.

An AVP-like neurohormone was extracted from suboesophageal and thoracic ganglia of Locusta migtatoria, isolated, characterized and synthesized. It functions as a diuretic hormone in this species by enhancing the excretion of urine from the MT. It appears to act by increasing cyclic AMP; synthetic AVP-like IDH increases cyclic AMP of the MT in vitro in a time-dependant, dose-dependant and very specific manner. 8-BR-cyclic AMP, an analog of cyclic AMP known to enter the cells, mimics the diuretic action of the AVP-like IDH. Furthermore, the combined actions of forskolin (the activator of the adenylate cyclase) and IBMX (the inhibitor of the phosphodiestherase activity) increase both MT cyclic AMP level and excretion of the primary urine. We conclude from these results that cyclic AMP is a second messenger of the AVO-like IDH.

1-Methyl-3-isobutylxanthine↗
PubMed2002

A possible molecular ancestor for mollusk APGWamide, insect adipokinetic hormone, and crustacean red pigment concentrating hormone.

Precursor structures of various members of the neuropeptide family adipokinetic hormone/red pigment concentrating hormone (AKH/RPCH) of mandibular arthropods and the APGWamide family of mollusks were compared. Amino acid alignments showed a common overall architecture (signal peptide, active peptide, related peptide), with a similar alpha helix-random coil secondary structure. DNA sequence alignments revealed close similarities between the genes encoding for the peptides of the two families. The APGWamide genes are larger than the AKH/RPCH genes. The sequence environment occupied by introns is similar in AKH/RPCH and APGWamide genes. Such similarities suggest that these peptide families might have been originated by gene rearrangements from a common ancestor having either an AKH/RPCH/APGWamide-like structure or both an AKH/RPCH-like and an APGWamide-like structures. In the former model, DNA fragments could have been gained when the ancestor evolved to mollusks and it could have lost nucleotides when the progression to mandibular arthropods took place. In the second model, AKH/RPCH-like structures could have been fused during evolution toward mandibular arthropods, whereas in mollusks they could have been lost with the possible amplification of the APGWamide-like structure. Loss of domains in exon 1 may have originated the signal peptide and the first codon of the active RPCH. In exon 2, loss of domains possibly determined the junctions of codons 2 to 5 with the loss of a APGWamide copy; exon 3 underwent fewer variations. The similarity of the mollusk APGWamide precursors is closer to that of the RPCH family than the insect AKH family, indicating an earlier evolutionary departure.

Amino Acid Sequence↗
PubMed1983

A kinetic analysis of the action of the insect prothoracicotropic hormone.

A modified in vitro assay was used to assess the kinetics of activation and the decay of activation of the prothoracic glands (PG) by the prothoracicotropic hormone (PTTH) in Manduca sexta. Time-courses of ecdysone synthesis by PTTH-activated day 3 larval and day 0 pupal PG were comparable both quantitatively and temporally, but dose-responses of PTTH activation revealed that larval glands were 1.8 times more sensitive to the neurohormone. The exposure time necessary for maximal activation of the PG by PTTH was the same for both glands, with half-maximal activation in approximately 0.5 min. Once PTTH was removed the rate of ecdysone synthesis by larval and pupal PG remained constant for about 2 h, after which the activated response for both glands decayed rapidly, reaching the unactivated basal synthesis rate within 45 min. These kinetics data suggest that PG activation by PTTH in vitro occurs in a manner indicative of activation in situ and, thus, that this in vitro system is suitable for probing the molecular mechanism by which PTTH activates the PG.

Animals↗
PubMed1998

Expression, processing and secretion of a proteolytically-sensitive insect diuretic hormone by Saccharomyces cerevisiae requires the use of a yeast strain lacking genes encoding the Yap3 and Mkc7 endoproteases found in the secretory pathway.

A system is described for the heterologous expression of peptides in Saccharomyces cerevisiae. A synthetic gene encoding a precursor of the 41 amino acid Manduca sexta diuretic hormone (Mas-DH) was expressed at 0.8 mg/l purified peptide. A precursor of a mutant peptide of Mas-DH, Mas-DH[K22Q] was also expressed. The peptides were purified, then treated with peptidylglycine alpha-amidating enzyme to generate the alpha-amidated, mature, form of Mas-DH or Mas-DH[K22Q], which were biologically active. Successful expression of full-length Mas-DH+Gly depended upon the use of a protease-deficient yeast strain. In wild-type strains, Mas-DH+Gly was recovered only as proteolytic fragments, even in the presence of various protease inhibitors. Expression of Mas-DH+Gly in strains deficient in either the Mkc7 or the Yap3 protease reduced proteolysis, while no proteolysis of Mas-DH+Gly was detectable in a strain lacking both proteases. This protease-deficient strain may prove of general utility for expression of peptides. Analysis of recovered proteolytic fragments revealed a complex pattern of cleavage sites. Both the Yap3 and Mkc7 proteases preferred to cleave at a single Glu-Lys downward arrow-Glu-Arg site. Analysis of secondary cleavage sites showed that Yap3 preferred to cleave after either Lys or Arg and Mkc7 after Lys. This paper is the first report on the in vivo activity and specificity of Yap3 and Mkc7 expressed at physiological levels.

Amino Acid Sequence↗
PubMed1977

Biological activity of insect juvenile hormone analogues against the stable fly and toxicity studies in domestic animals.

The insect JHAs are effective inhibitors of adult stable fly development. Laboratory and field evaluation studies demonstrated that area application of the analogues to larval breeding sites was efficacious for stable fly control in cattle feed lots and in marine grasses. Analytical methods by quantification with gas chromatography with flame ionization detection was developed to measure residual properties as well as aging and leaching in fly breeding media. The analogues did not interfere with the oviposition and development of the endoparasites, M. raptor and S. endius. Toxicity studies against swine, hamsters, and sheep showed that when compounds of high purity were used that no toxic effects were observed in any of the species.

Animals↗
PubMed2003

Insect peptide hormones: a selective review of their physiology and potential application for pest control.

Our knowledge on primary structure, synthesis, release, receptor binding, structure-activity relationships, mode of action and degradation of, mainly, neuropeptides from insects has increased dramatically during the last 10 years or so. Here, five case studies are presented, which deal selectively with effects on: reproduction (trypsin modulating oostatic factor in mosquito); energy metabolism, locomotion and the immune system (adipokinetic hormones); water and ion balance, and feeding behaviour (diuretic hormones, kinins, sulfakinins); sex attraction (pheromone biosynthesis activating neuropeptide); and growth and development, and muscle activity (allatostatins). The literature is reviewed in the context of how the knowledge on neuropeptides has been and can be used for the design of novel, safe and selective compounds to control pest insects in the foreseeable future.

Amino Acid Sequence↗
PubMed1976

Hormonal control of growth and differentiation of insect tissues cultured in vitro.

This paper reviews the effects of insect hormones on lepidopteran imaginal discs cultured in vitro. Beta-ecdysone showed that RNA and protein synthesis was required for evagination and cuticle deposition. In particular, studies with actinomycin D and cycloheximide (at nontoxic levels) showed that RNA and protein synthesis during the ecdysone-dependent period was essential for subsequent development. These findings support the hypothesis that stimulation of macromolecular synthesis is fundamental to the action of ecdysone on imaginal discs. The influence of beta-ecdysone on chitin synthesis was also examined. Beta-ecdysone stimulated uptake and incorporation of tritiated-glucosamine by cultured P.interpunctella wing discs. Addition of hexosamines to the culture medium had no influence on ecdysone-induced cuticle deposition, but inhibition of glucose-uptake by cytochalasin B prevented the formation of cuticle. The action of ecdysone on particular enzymes in the chitin pathway remains to be elucidated.timulated both evatination and cuticle deposition of wing discs of Plodia interpunctella(Hubner). However, evagination required a shorter exposure to ecdysone than did cuticle deposition. Cuticle deposition was obtained under the following conditions: (a) a 24-hour pulse of beta-ecdysone (0.5-5.0 mug/ml); (b) continuous treatment with 0.2 mug/ml beta-ecdysone; or (c) continuous treatment with 0.5 to 50.0 mug/ml beta-ecdysone in medium conditioned with larval fat body...

Acetylglucosamine↗
PubMed2002

Diastereomeric ecdysteroids with a cyclic hemiacetal in the side chain produced by cytochrome P450 in hormonally resistant insect cells.

A microsomal cytochrome P450 from a cell line of the insect Chironomus tentans has been shown to hydroxylate the steroid hormone 20-hydroxyecdysone at C(26) to yield 20,26-dihydroxyecdysone, P1, which is further metabolized to P2 and P3. Based on (1)H NMR studies, acetonide formation and quantum chemical calculations, P2 and P3 represent novel slowly interconvertible geometrical isomers, occurring at a 3:1 ratio, presumably arising from hemiacetal formation between the 26-aldehyde group and the 22R-hydroxyl group to build a tetrahydropyran ring in the side chain. The stereochemistry at C(26) was S in P2 (trans-diol) and R in P3 (cis-diol), respectively. Both metabolites showed S configuration at C(25). With Chironomus cells, P2/P3 was inactive as both a hormonal agonist and antagonist, whereas 20,26-dihydroxyecdysone (P1) showed weak agonist activity. Thus, cytochrome P450-mediated inactivation of 20-hydroxyecdysone may be responsible for the hormonal insensitivity observed in some subclones of this cell line.

Acetals↗
PubMed2005

The mevalonate pathway and the synthesis of juvenile hormone in insects.

The mevalonate pathway in insects has two important peculiarities, the absence of the sterol branch and the synthesis of juvenile hormone (JH), that may have influenced the mechanisms of regulation. The data available on these mechanisms indicate that cholesterol does not play a regulatory role and that JH modulates transcript levels of a number of genes of the mevalonate pathway or can influence the translatability and/or stability of the transcripts themselves. These data suggest that the mevalonate pathway in insects can best be interpreted in terms of coordinated regulation, in which regulators act in parallel to a number of enzymes, as occurs in the cholesterol-driven pathway in vertebrates.

Animals↗
PubMed1998

Expression and purification of biologically active porcine follicle-stimulating hormone in insect cells bearing a baculovirus vector.

Biologically active recombinant porcine FSH (rec-pFSH) free from the cognate pituitary glycoprotein hormone LH was produced. It was synthesized by a baculovirus vector-insect cell system using two cDNAs encoding the glycoprotein alpha and FSH beta subunits. Its antigenicity was the same as that of pFSH prepared from the pituitary. Glycosylation of rec-pFSH was shown by tunicamycin treatment but the molecular mass of each subunit was lower than that of pituitary-derived FSH, because of the absence of trimming of terminal sugars in insect cells. Rec-pFSH was secreted into the culture medium at about 1 mg/l and purified in six fractions, because of the heterogeneity of the sugar group, by S-Sepharose and concanavalin A-Sepharose column chromatography. The biological activity of rec-pFSH was examined by measuring its effect on progesterone secretion from porcine granulosa cells and germinal vesicle breakdown (GVBD) of porcine oocytes. It showed adequate activity with respect to progesterone secretion, although some fractions rich in the sugar group showed lower activity than that of pituitary-derived FSH. It exhibited higher GVBD activity than that of pituitary-derived FSH at concentrations as low as 1 ng/ml. These results demonstrate that the baculovirus vector-insect cell system can provide biologically active rec-pFSH.

Animals↗