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Biotechnology and Applied Biochemistry 2013Juvenile hormones (JHs) represent a family of sesquiterpenoid hormones in insects, and they play a key role in regulating development, metamorphosis, and reproduction.... (Review)
Review
Juvenile hormones (JHs) represent a family of sesquiterpenoid hormones in insects, and they play a key role in regulating development, metamorphosis, and reproduction. The last two steps of the JH biosynthetic pathway, epoxidation and methyl esterification of farnesoic acid to JH, are insect specific, and thus have long been considered a promising target for biorational insecticides. Recently, the enzymes involved in the last two steps have been molecularly identified: JH acid methyltransferase catalyzes the esterification step and the cytochrome P450 CYP15 enzyme catalyzes the epoxidation step. In this review, we describe the recent progress on the characterization of JH biosynthetic enzymes, with special focus on the function and diversity of the CYP15 family. CYP15 genes have evolved lineage-specific substrate specificity and regulatory mechanisms in insects, which appear to be associated with the lineage-specific acquisition of unique JH structure and function. In addition, the lack of CYP15 genes in crustacean (Daphnia pulex) and arachnid (Tetranychus urticae) species, whose genomes have been fully sequenced, may imply that CYP15 enzymes are an evolutionary innovation in insects to use the epoxide forms of methylated farnesoid molecules as their principal JHs. Molecular identification and characterization of CYP15 genes from broad taxa of insects have paved the way to the design of target-specific, biorational anti-JH agents.
Topics: Animals; Cytochrome P-450 Enzyme System; Insecta; Juvenile Hormones
PubMed: 23586995
DOI: 10.1002/bab.1058 -
Journal of Insect Physiology Sep 2015
Topics: Animals; Insecta; Juvenile Hormones
PubMed: 26253750
DOI: 10.1016/j.jinsphys.2015.07.016 -
Hormonal regulation of insect metamorphosis with special reference to juvenile hormone biosynthesis.Current Topics in Developmental Biology 2013Ecdysteroids and juvenile hormones (JHs) are key hormones that are responsible for insect molting and metamorphosis. JH maintains the larval state and the decline of its... (Review)
Review
Ecdysteroids and juvenile hormones (JHs) are key hormones that are responsible for insect molting and metamorphosis. JH maintains the larval state and the decline of its level in the hemolymph is crucial to elicit transformation to the pupal stage; therefore, the precise control of JH biosynthesis is necessary for normal development and the initiation of metamorphosis. This chapter summarizes mechanisms of the regulation of JH biosynthesis by the corpora allata and shows that several factors such as ecdysteroids, neurotransmitters, and peptides act together in the stage-specific manner to guarantee the accurate production of JH in each stage, in particular, in the last larval stage when metamorphosis is initiated with the transformation of the larva to the pupa. In addition, recent progress in understanding the JH signaling pathway is briefly discussed, including the identification of a long elusive JH receptor.
Topics: Animals; Insecta; Juvenile Hormones; Metamorphosis, Biological; Molting; Signal Transduction
PubMed: 23347516
DOI: 10.1016/B978-0-12-385979-2.00003-4 -
Science (New York, N.Y.) Aug 1976Two simple chromenes with anti-JH activity have been isolated and identified from the bedding plant Ageratum houstoianum. By contact and fumigation these compounds...
Two simple chromenes with anti-JH activity have been isolated and identified from the bedding plant Ageratum houstoianum. By contact and fumigation these compounds induce precocious metamorphosis and sterilization in several hemipteran species of insects. Certain holometabolous species are sterilized, forced into diapause, or both. Each of these biological actions is equivalent to removal of the corpora allata, which produce the JH's, and is reversible by treatment with exogenous JH. Thus, the action of these compounds is to stop the production or depress the titer of the JH's. To our knowledge, this is the first discovery of anti-JH, and we hope it will guide the way to the emergence of a fourth generation of safe and insect-specific pesticides.
Topics: Female; Hibernation; Insect Control; Insecta; Insecticides; Juvenile Hormones; Metamorphosis, Biological; Neurosecretory Systems; Ovary; Ovum; Plants
PubMed: 986685
DOI: 10.1126/science.986685 -
Journal of Insect Physiology Jun 2008
Topics: Animals; Insecta; Juvenile Hormones
PubMed: 18514706
DOI: 10.1016/j.jinsphys.2008.04.014 -
Annals of the New York Academy of... Apr 2009Juvenile hormones (JH), produced by the corpora allata, have an essential role in growth and development, morphogenesis, and reproductive processes of insects. The... (Review)
Review
Juvenile hormones (JH), produced by the corpora allata, have an essential role in growth and development, morphogenesis, and reproductive processes of insects. The output of JH and circulating titer are required to be precisely regulated throughout the insect's life in response to developmental requirements and environmental factors. The synthesis of JH must be periodically turned off and on, or finely tuned, in a highly coordinated way. Except for a few key or intensely studied insect species, the control of synthesis of JH by regulatory peptides remains largely undefined and many of the details remain obscure. Several different classes of neuropeptide are believed to be involved in the regulation of corpus allatum function and hence JH output. In different insect species and at different stages of development, these regulatory peptides may include at least three types of inhibitory allatostatins, at least one type of stimulatory allatotropin, and perhaps several other, as yet largely undefined, additional neuropeptides. The details of how each of these peptides acts to affect JH production and their relationship to each other in the coordination of JH synthesis remain to be established. There are several insect orders for which almost nothing is known concerning the regulation of JH synthesis and the peptides that might be involved. Current proteomic and genomic studies are helping to redress this balance but at the same time posing new questions. Other neuropeptides are implicated in the regulation of JH production, and there is new evidence concerning the mode of action of allatotropins.
Topics: Animals; Biological Transport; Humans; Juvenile Hormones; Neuropeptides; Protein Precursors
PubMed: 19456353
DOI: 10.1111/j.1749-6632.2009.04459.x -
Annual Review of Entomology 1998Agrochemical research over the last two decades has resulted in the discovery of chemically novel insecticides that mimic the action of the two insect growth and... (Review)
Review
Agrochemical research over the last two decades has resulted in the discovery of chemically novel insecticides that mimic the action of the two insect growth and developmental hormones, the steroidal 20-hydroxyecdysone (20E) and the sesquiterpenoid juvenile hormone (JH). Bisacylhydrazines are non-steroidal agonists of 20E and exhibit their insecticidal activity via interaction with the ecdysteroid receptor proteins. Interestingly, two of the bisacylhydrazine (tebufenozide and RH-2485) insecticides are very selectively toxic to lepidopteran pests. These insecticides are safe to beneficial insects and have a benign ecotoxicological profile. Aromatic non-terpenoidal insecticides (fenoxycarb and pyriproxyfen) mimic the action of JHs. However, like the JHs, their exact mode of action is not well understood. These insecticides are toxic to a broad spectrum of insects during their embryonic, last larval, or reproductive stages. The insecticidal, ecotoxicological properties and the mode of action of the two groups of insecticides are reviewed in this article.
Topics: Animals; Ecdysteroids; Forecasting; Hydrazines; Insecta; Insecticides; Juvenile Hormones; Molecular Mimicry; Molecular Structure; Steroids
PubMed: 9444757
DOI: 10.1146/annurev.ento.43.1.545 -
Annual Review of Entomology 2007Allatostatins are pleiotropic neuropeptides for which one function in insects is the inhibition of juvenile hormone synthesis. Juvenile hormone, an important regulator... (Review)
Review
Allatostatins are pleiotropic neuropeptides for which one function in insects is the inhibition of juvenile hormone synthesis. Juvenile hormone, an important regulator of development and reproduction in insects, is produced by the corpora allata. Mandibular organs, the crustacean homologs of insect corpora allata, produce precursors of juvenile hormone with putatively similar functions. Three types of allatostatins in insects have been isolated: FGLamides, W(X)(6)Wamides, and PISCFs. All act rapidly and reversibly; however, although these types occur in all groups of insects studied, they act as inhibitors of juvenile hormone production in only some groups. Only the FGLamide-type peptides have been isolated in crustaceans, in which they may function to stimulate production of hormone by the mandibular glands, as occurs in early cockroach embryos. Much remains to be learned in order to understand the role of allatostatins in the modulation of hormone production.
Topics: Animals; Corpora Allata; Crustacea; Drosophila Proteins; Insecta; Juvenile Hormones; Neuropeptides; Receptors, G-Protein-Coupled; Receptors, Neuropeptide
PubMed: 16968202
DOI: 10.1146/annurev.ento.51.110104.151050 -
Developmental Neuroscience 1996Juvenile hormone regulates metamorphosis in insects, and its effects on the nervous system during the larval-pupal transition have been studied primarily in the hawk... (Review)
Review
Juvenile hormone regulates metamorphosis in insects, and its effects on the nervous system during the larval-pupal transition have been studied primarily in the hawk moth, Manduca sexta. The effects of juvenile hormone on the nervous system of adult insects have been little studied. Elucidating the role of juvenile hormone during behavioral development in adult honey bees provides an opportunity to study hormone regulation of nervous system structure and function in an insect with a rich behavioral repertoire and social life. A worker honey bee typically lives 30-60 days. During this time, she performs a sequence of different tasks that sustain the colony. A striking behavioral transition typically occurs at about 3 weeks of age. At this time, worker bees stop performing within-hive tasks such as rearing brood and building comb and begin to forage outside the hive. This behavioral development is accompanied by a marked increase in the production of juvenile hormone. The mushroom bodies of the protocerebrum, the region of the insect brain most often associated with learning and memory, also undergo an internal reorganization during behavioral development. High titers of juvenile hormone and an increased volume of neuropil associated with the mushroom bodies are characteristic of the forager. Importantly, the time of the behavioral transition to foraging is not fixed. Individual bees can respond to changing colony or environmental conditions by accelerating or delaying the switch from within-hive tasks to foraging. For example, in the absence of older workers, some bees will undergo precocious development and may forage as early as 4 days of age. These workers also experience a precocious rise in juvenile hormone and an earlier reorganization of the mushroom bodies. Our current studies investigate the roles played by juvenile hormone and experience in shaping the mushroom bodies of the adult honey bee, and the relationship of these changes to the bee's ability to forage successfully. It is proposed that juvenile hormone may mediate neural plasticity in the brains of adult honey bees to support the demanding cognitive task of foraging.
Topics: Animals; Bees; Behavior, Animal; Brain; Juvenile Hormones
PubMed: 8840089
DOI: 10.1159/000111474 -
Insect Biochemistry and Molecular... Jan 2020This study reports the development and application of a liquid chromatography method coupled to electrospray tandem mass spectrometry (LC-MS/MS) for the identification...
Common structural features facilitate the simultaneous identification and quantification of the five most common juvenile hormones by liquid chromatography-tandem mass spectrometry.
This study reports the development and application of a liquid chromatography method coupled to electrospray tandem mass spectrometry (LC-MS/MS) for the identification and quantification of the five most common juvenile hormone (JH) homologs and methyl farnesoate (MF). The protocol allows the simultaneous analysis in a single LC run of JH I, JH II, JH III, JH III bisepoxide (JHB) and JH III skipped bisepoxide (JHSB). The identification of JHs is based on multiple reaction monitoring (MRM), using two of the most abundant fragmentation transitions for each hormone. Addition of deuterated JH III as an internal standard permits the absolute quantification of the different JHs. The JH homologs common structural features led to similar chromatographic behavior, as well as related fragmentation patterns, which facilitated the simultaneous detection of all the homologs in a single LC-MS/MS run. The protocol detects JHs in the low femtomole range, allowing often the analysis of JH in individual insects. Fragmentation of each of the JH homologs generates unique diagnostic ions that permitted the identification and quantification of JHs from samples of different species of Diptera, Lepidoptera, Heteroptera and Hymenoptera. Having a simple protocol, which can undisputedly determine the identity of the homologs present in a particular species, provides us with the opportunity to identify and quantify JHs existing in insects that are pests, vector of diseases or important research models.
Topics: Animals; Chromatography, Liquid; Diptera; Heteroptera; Hymenoptera; Juvenile Hormones; Lepidoptera; Tandem Mass Spectrometry
PubMed: 31760138
DOI: 10.1016/j.ibmb.2019.103287