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Steven J. Seybold - One of the best experts on this subject based on the ideXlab platform.
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isolation and extreme sex specific expression of cytochrome p450 genes in the bark beetle Ips paraconfusus following feeding on the phloem of host ponderosa pine pinus ponderosa
Insect Molecular Biology, 2007Co-Authors: M L Erickson, Dezene P W Huber, Christian M Leutenegger, Joerg Bohlmann, Steven J. SeyboldAbstract:We have identified cDNAs and characterized the expression of 13 novel cytochrome P450 genes of potential importance in host colonization and reproduction by the California fivespined Ips, Ips paraconfusus. Twelve are of the Cyp4 family and one is of the Cyp9 family. Following feeding on host Pinus ponderosa phloem, bark beetle transcript levels of several of the Cyp4 genes increased or decreased in males only or in both sexes. In one instance (IparaCyp4A5) transcript accumulated significantly in females, but declined significantly in males. The Cyp9 gene (Cyp9T1) transcript levels in males were > 85 000 x higher at 8 h and > 25 000 x higher at 24 h after feeding compared with nonfed controls. Transcript levels in females were approximately 150 x higher at 24 h compared with nonfed controls. Cyp4G27 transcript was present constitutively regardless of sex or feeding and served as a better housekeeping gene than beta-actin or 18S rRNA for the real-time TaqMan polymerase chain reaction analysis. The expression patterns of Cyp4AY1, Cyp4BG1, and, especially, Cyp9T1 in males suggest roles for these genes in male-specific aggregation pheromone production. The differential transcript accumulation patterns of these bark beetle P450s provide insight into ecological interactions of I. paraconfusus with its host pines.
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Pine monoterpenes and pine bark beetles: a marriage of convenience for defense and chemical communication
Phytochemistry Reviews, 2006Co-Authors: Steven J. Seybold, Dezene P W Huber, Jana C. Lee, Andrew D. Graves, Jörg BohlmannAbstract:Pine-feeding bark beetles (Coleoptera: Scolytidae) interact chemically with their host pines (Coniferales: Pinaceae) via the behavioral, physiological, and biochemical effects of one class of isoprenoids, the monoterpenes and their derivatives. Pine monoterpenes occur in the oleoresin and function as behaviorally active kairomones for pine bark beetles and their predators, presenting a classic example of tri-trophic chemical communication. The monoterpenes are also essential co-attractants for pine bark beetle aggregation pheromones. Ironically, pine monoterpenes are also toxic physiologically to bark beetles at high vapor concentrations and are considered an important component of the defense of pines. Research over the last 30 years has demonstrated that some bark beetle aggregation pheromones arise through oxygenation of monoterpenes, linking pheromone biosynthesis to the host pines. Over the last 10 years, however, several frequently occurring oxygenated monoterpene pheromone components (e.g., Ipsenol, Ipsdienol and frontalin) have also been shown to arise through highly regulated de novo pathways in the beetles (reviewed in Seybold and Tittiger, 2003). The most interesting nexus between these insects and their plant hosts involves the late-stage reactions in the monoterpenoid biosynthetic pathway, during which isomeric dimethylallyl diphosphate and isopentenyl diphosphate are ultimately elaborated to stereospecific monoterpenes in the trees and to hydroxylated monoterpenes or bicyclic acetals in the insects. There is signal stereospecificity in both production of and response to the monoterpenoid aggregation pheromones of bark beetles and in response to␣the monoterpenes of the pines. In the California fivespined Ips, Ips paraconfusus, we have discovered a number of cytochome P450 genes that have expression patterns indicating that they may be involved in detoxifying monoterpene secondary metabolites and/or biosynthesizing pheromone components. Both processes result in the production of oxygenated monoterpenes, likely with varying degrees of stereospecificity. A behavioral analysis of the stereospecific response of I. paraconfusus to its pheromone is providing new insights into the development of an efficacious bait for the detection of this polyphagous insect in areas outside the western United States. In contrast, a Eurasian species that has arrived in California, the Mediterranean pine engraver, Orthotomicus (Ips) erosus, utilizes both a monoterpenoid (Ipsdienol) and a hemiterpenoid (2-methyl-3-buten-2-ol) in its pheromone blend. The stereospecificity of the response of O. erosus to the monoterpenoid appears to be the key factor to the improved potency of the attractant bait for this invasive species.
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insect pheromones an overview of biosynthesis and endocrine regulation
Insect Biochemistry and Molecular Biology, 1999Co-Authors: Julie A Tillman, Steven J. Seybold, Russell A Jurenka, Gary J. BlomquistAbstract:This overview describes, compares, and attempts to unify major themes related to the biosynthetic pathways and endocrine regulation of insect pheromone production. Rather than developing and dedicating an entirely unique set of enzymes for pheromone biosynthesis, insects appear to have evolved to add one or a few tissue-specific auxiliary or modified enzymes that transform the products of “normal” metabolism to pheromone compounds of high stereochemical and quantitative specificity. This general understanding is derived from research on model species from one exopterygote insect order (Blattodea) and three endopterygote insect orders (Coleoptera, Diptera, and Lepidoptera). For instance, the ketone hydrocarbon contact sex pheromone of the female German cockroach, Blattella germanica, derives its origins from fatty acid biosynthesis, arising from elongation of a methyl-branched fatty acyl‐CoA moiety followed by decarboxylation, hydroxylation, and oxidation. Coleopteran sex and aggregation pheromones also arise from modifications of fatty acid biosynthesis or other biosynthetic pathways, such as the isoprenoid pathway (e.g. Cucujidae, Curculionidae, and Scolytidae), or from simple transformations of amino acids or other highly elaborated host precursors (e.g. Scarabaeidae and Scolytidae). Like the sex pheromone of B. germanica, female-produced dipteran (e.g. Drosophilidae and Muscidae) sex pheromone components originate from elongation of fatty acyl‐CoA moieties followed by loss of the carbonyl carbon and the formation of the corresponding hydrocarbon. Female-produced lepidopteran sex pheromones are also derived from fatty acids, but many moths utilize a species-specific combination of desaturation and chain-shortening reactions followed by reductive modification of the carbonyl carbon. Carbon skeletons derived from amino acids can also be used as chain initiating units and elongated to lepidopteran pheromones by this pathway (e.g. Arctiidae and Noctuidae). Insects utilize at least three hormonal messengers to regulate pheromone biosynthesis. Blattodean and coleopteran pheromone production is induced by juvenile hormone III (JH III). In the female common house fly, Musca domestica, and possibly other species of Diptera, it appears that during hydrocarbon sex pheromone biosynthesis, ovarian-produced ecdysteroids regulate synthesis by affecting the activities of one or more fatty acyl‐CoA elongation enzyme(s) (elongases). Lepidopteran sex pheromone biosynthesis is often mediated by a 33 or 34 amino acid pheromone biosynthesis activating neuropeptide (PBAN) through alteration of enzyme activities at one or more steps prior to or during fatty acid synthesis or during modification of the carbonyl group. Although a molecular level understanding of the regulation of insect pheromone biosynthesis is in its infancy, in the male California fivespined Ips, Ips paraconfusus (Coleoptera: Scolytidae), JH III acts at the transcriptional level by increasing the abundance of mRNA for 3-hydroxy-3-methylglutaryl-CoA reductase, a key enzyme in de novo isoprenoid aggregation pheromone biosynthesis. © 1999 Elsevier Science Ltd. All rights reserved.
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insect pheromones an overview of biosynthesis and endocrine regulation
Insect Biochemistry and Molecular Biology, 1999Co-Authors: Julie A Tillman, Steven J. Seybold, Russell A Jurenka, Gary J. BlomquistAbstract:Abstract This overview describes, compares, and attempts to unify major themes related to the biosynthetic pathways and endocrine regulation of insect pheromone production. Rather than developing and dedicating an entirely unique set of enzymes for pheromone biosynthesis, insects appear to have evolved to add one or a few tissue-specific auxiliary or modified enzymes that transform the products of “normal” metabolism to pheromone compounds of high stereochemical and quantitative specificity. This general understanding is derived from research on model species from one exopterygote insect order (Blattodea) and three endopterygote insect orders (Coleoptera, Diptera, and Lepidoptera). For instance, the ketone hydrocarbon contact sex pheromone of the female German cockroach, Blattella germanica, derives its origins from fatty acid biosynthesis, arising from elongation of a methyl-branched fatty acyl–CoA moiety followed by decarboxylation, hydroxylation, and oxidation. Coleopteran sex and aggregation pheromones also arise from modifications of fatty acid biosynthesis or other biosynthetic pathways, such as the isoprenoid pathway (e.g. Cucujidae, Curculionidae, and Scolytidae), or from simple transformations of amino acids or other highly elaborated host precursors (e.g. Scarabaeidae and Scolytidae). Like the sex pheromone of B. germanica, female-produced dipteran (e.g. Drosophilidae and Muscidae) sex pheromone components originate from elongation of fatty acyl–CoA moieties followed by loss of the carbonyl carbon and the formation of the corresponding hydrocarbon. Female-produced lepidopteran sex pheromones are also derived from fatty acids, but many moths utilize a species-specific combination of desaturation and chain-shortening reactions followed by reductive modification of the carbonyl carbon. Carbon skeletons derived from amino acids can also be used as chain initiating units and elongated to lepidopteran pheromones by this pathway (e.g. Arctiidae and Noctuidae). Insects utilize at least three hormonal messengers to regulate pheromone biosynthesis. Blattodean and coleopteran pheromone production is induced by juvenile hormone III (JH III). In the female common house fly, Musca domestica, and possibly other species of Diptera, it appears that during hydrocarbon sex pheromone biosynthesis, ovarian-produced ecdysteroids regulate synthesis by affecting the activities of one or more fatty acyl–CoA elongation enzyme(s) (elongases). Lepidopteran sex pheromone biosynthesis is often mediated by a 33 or 34 amino acid pheromone biosynthesis activating neuropeptide (PBAN) through alteration of enzyme activities at one or more steps prior to or during fatty acid synthesis or during modification of the carbonyl group. Although a molecular level understanding of the regulation of insect pheromone biosynthesis is in its infancy, in the male California fivespined Ips, Ips paraconfusus (Coleoptera: Scolytidae), JH III acts at the transcriptional level by increasing the abundance of mRNA for 3-hydroxy-3-methylglutaryl-CoA reductase, a key enzyme in de novo isoprenoid aggregation pheromone biosynthesis.
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Insect pheromones—an overview of biosynthesis and endocrine regulation
Insect biochemistry and molecular biology, 1999Co-Authors: Julie A Tillman, Steven J. Seybold, Russell A Jurenka, Gary J. BlomquistAbstract:Abstract This overview describes, compares, and attempts to unify major themes related to the biosynthetic pathways and endocrine regulation of insect pheromone production. Rather than developing and dedicating an entirely unique set of enzymes for pheromone biosynthesis, insects appear to have evolved to add one or a few tissue-specific auxiliary or modified enzymes that transform the products of “normal” metabolism to pheromone compounds of high stereochemical and quantitative specificity. This general understanding is derived from research on model species from one exopterygote insect order (Blattodea) and three endopterygote insect orders (Coleoptera, Diptera, and Lepidoptera). For instance, the ketone hydrocarbon contact sex pheromone of the female German cockroach, Blattella germanica, derives its origins from fatty acid biosynthesis, arising from elongation of a methyl-branched fatty acyl–CoA moiety followed by decarboxylation, hydroxylation, and oxidation. Coleopteran sex and aggregation pheromones also arise from modifications of fatty acid biosynthesis or other biosynthetic pathways, such as the isoprenoid pathway (e.g. Cucujidae, Curculionidae, and Scolytidae), or from simple transformations of amino acids or other highly elaborated host precursors (e.g. Scarabaeidae and Scolytidae). Like the sex pheromone of B. germanica, female-produced dipteran (e.g. Drosophilidae and Muscidae) sex pheromone components originate from elongation of fatty acyl–CoA moieties followed by loss of the carbonyl carbon and the formation of the corresponding hydrocarbon. Female-produced lepidopteran sex pheromones are also derived from fatty acids, but many moths utilize a species-specific combination of desaturation and chain-shortening reactions followed by reductive modification of the carbonyl carbon. Carbon skeletons derived from amino acids can also be used as chain initiating units and elongated to lepidopteran pheromones by this pathway (e.g. Arctiidae and Noctuidae). Insects utilize at least three hormonal messengers to regulate pheromone biosynthesis. Blattodean and coleopteran pheromone production is induced by juvenile hormone III (JH III). In the female common house fly, Musca domestica, and possibly other species of Diptera, it appears that during hydrocarbon sex pheromone biosynthesis, ovarian-produced ecdysteroids regulate synthesis by affecting the activities of one or more fatty acyl–CoA elongation enzyme(s) (elongases). Lepidopteran sex pheromone biosynthesis is often mediated by a 33 or 34 amino acid pheromone biosynthesis activating neuropeptide (PBAN) through alteration of enzyme activities at one or more steps prior to or during fatty acid synthesis or during modification of the carbonyl group. Although a molecular level understanding of the regulation of insect pheromone biosynthesis is in its infancy, in the male California fivespined Ips, Ips paraconfusus (Coleoptera: Scolytidae), JH III acts at the transcriptional level by increasing the abundance of mRNA for 3-hydroxy-3-methylglutaryl-CoA reductase, a key enzyme in de novo isoprenoid aggregation pheromone biosynthesis.
David L Wood - One of the best experts on this subject based on the ideXlab platform.
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Relationship between a host plant compound, myrcene and pheromone production in the bark beetle, Ips paraconfusus
Journal of Insect Physiology, 2007Co-Authors: John A. Byers, Lloyd E. Browne, R. H. Fish, B. Piatek, David L Wood, L.b. HendryAbstract:Abstract The pheromonal components, Ipsenol and Ipsdienol were found in increasing quantities in hindguts of only the male sex of Ips paraconfusus following exposure of both sexes to a series of increasing concentrations of myrcene vapour. Hindguts of female and male beetles contained similar quantities of myrcene and other volatile compounds associated with myrcene exposure. Unexposed beetles of both sexes did not contain detectable amounts of any volatile compound. This indicates that myrcene induces or is a precursor for sex-specific pheromone biosynthesis.
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feeding response of Ips paraconfusus to phloem and phloem metabolites of heterobasidion annosum inoculated ponderosa pine pinus ponderosa
Journal of Chemical Ecology, 2003Co-Authors: William R Mcnee, David L Wood, Andrew J. Storer, Pierluigi Bonello, Thomas R. GordonAbstract:In studies of feeding by the bark beetle, Ips paraconfusus, two pine stilbenes (pinosylvin and pinosylvin methyl ether), ferulic acid glucoside, and enantiomers of the four most common sugars present in ponderosa pine phloem (sucrose, glucose, fructose, and raffinose) did not stimulate or reduce male feeding when assayed on wet α-cellulose with or without stimulatory phloem extractives present. When allowed to feed on wet α-cellulose containing sequential extracts (hexane, methanol, and water) of ponderosa pine phloem, methanol and water extractives stimulated feeding, but hexane extractives did not. Males confined in wet α-cellulose containing aqueous or organic extracts of culture broths derived from phloem tissue and containing the root pathogen, Heterobasidion annosum, ingested less substrate than beetles confined to control preparations. In an assay using logs from uninoculated ponderosa pines, the mean lengths of phloem in the digestive tracts increased as time spent feeding increased. Males confined to the phloem of basal logs cut from ponderosa pines artificially inoculated with H. annosum ingested significantly less phloem than beetles in logs cut from trees that were (combined) mock-inoculated or uninoculated and did not contain the pathogen. However, individual pathogen-containing treatments were not significantly different from uninoculated controls. It was concluded that altered feeding rates are not a major factor which may explain why diseased ponderosa pines are colonized by I. paraconfusus.
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Effects of pitch canker pathogen on gallery excavation and oviposition by Ips paraconfusus (Coleoptera: Scolytidae)
The Canadian Entomologist, 2002Co-Authors: Andrew J. Storer, David L Wood, Thomas R. GordonAbstract:Ips paraconfusus Lanier est un vecteur du champignon pathogene qui cause le chancre fusarien du pin, Fusarium circinatum Nirenberg et O'Donnell, en Californie. Les infections multiples sur les branches et les rameaux principaux du pin de Monterey, Pinus radiata D. Don. (Pinaceae), semblent predisposer les arbres aux infestations d'I. paraconfusus. La presence des chancres apparus en reaction au pathogene affectent apparemment la ponte et la construction de tunnels. Les scolytes introduits dans des chancres naturels et des chancres provoques artificiellement ont moins de chances de pondre que les scolytes introduits dans des troncs sains et leurs tunnels sont plus courts. Chez tous les adultes qui produisent des oeufs, le nombre moyen d'oeufs par adulte est le meme dans les troncs sains et dans les troncs malades; cependant, la distance entre le point de transmission de la maladie et le premier oeuf, mesuree perpendiculairement au grain du bois, est plus grande chez les adultes introduits dans les chancres que chez ceux qui sont inseres loin des chancres. Ces resultats indiquent que le pathogene responsable du chancre fusarien du pin a un effet negatif sur I. paraconfusus parce que les chancres apparus en reaction au pathogene ne peuvent etre exploites par le scolyte.
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Pre-Emergence Feeding in Bark Beetles (Coleoptera: Scolytidae)
Environmental Entomology, 2000Co-Authors: William R Mcnee, David L Wood, Andrew J. StorerAbstract:Dissection of digestive tracts showed that five bark beetle species, Ips paraconfusus Lanier, Dendroctonus jeffreyi Hopkins, Tomicus piniperda (L.), Scolytus multistriatus (Marsham), and Phloeosinus sequoiae Hopkins, feed beneath the bark as callow adults before emergence from their brood trees. T. piniperda, S. multistriatus, and P. sequoiae also feed in host shoots before colonizing trees in which reproduction occurs. Callow I. paraconfusus and D. jeffreyi were found to ingest food material once the cuticle became yellow, whereas callow T. piniperda and S. multistriatus did not feed until their cuticles were light brown and black, respectively. Feeding behavior differed between the sexes only in D. jeffreyi, in which yellow males contained less food material than yellow females. Yellow I. paraconfusus removed from beneath the bark of Monterey pine, Pinus radiata D. Don, did not blacken without additional feeding, and some starved, brown adults became black. Callow adults that were allowed to feed survived longer and became darker-colored individuals more frequently than starved beetles. The potential benefits of pre-emergence feeding are discussed.
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de novo biosynthesis of the aggregation pheromone components Ipsenol and Ipsdienol by the pine bark beetles Ips paraconfusus lanier and Ips pini say coleoptera scolytidae
Proceedings of the National Academy of Sciences of the United States of America, 1995Co-Authors: Steven J. Seybold, Julie A Tillman, D R Quilici, Désirée Vanderwel, David L WoodAbstract:Abstract The California five-spined Ips, Ips paraconfusus Lanier, produces the myrcene-derived acyclic monoterpene alcohols Ipsenol (2-methyl-6-methylene-7-octen-4-ol) and Ipsdienol (2-methyl-6-methylene-2,7-octadien-4-ol) as components of its aggregation pheromone. The pine engraver beetle, Ips pini (Say), produces only Ipsdienol. Previous studies have shown that myrcene, a monoterpene in the pines colonized by these beetles, is a direct precursor to these pheromone components. In vivo radiolabeling studies reported here showed that male I. paraconfusus incorporated [1-14C]acetate into Ipsenol, Ipsdienol, and amitinol (trans-2-methyl-6-methylene-3,7-octadien-2-ol), while male I. pini incorporated [1-14C]acetate into Ipsdienol and amitinol. Females of these species produced neither labeled nor unlabeled pheromone components. The purified radiolabeled monoterpene alcohols from-males were identified by comparison of their HPLC and GC retention times with those of unlabeled standards. HPLC-purified fractions containing the individual radiolabeled components were analyzed by GC-MS and were shown to include only the pure alcohols. To further confirm that Ipsdienol and Ipsenol were radiolabeled, diastereomeric ester derivatives of the isolated alcohols were synthesized and analyzed by HPLC and GC-MS. After derivatization of the radiolabeled alcohols, the HPLC analysis demonstrated expected shifts in retention times with conservation of naturally occurring stereochemistry. The results provide direct evidence for de novo biosynthesis of Ipsenol, Ipsdienol, and amitinol by bark beetles.
Dezene P W Huber - One of the best experts on this subject based on the ideXlab platform.
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isolation and extreme sex specific expression of cytochrome p450 genes in the bark beetle Ips paraconfusus following feeding on the phloem of host ponderosa pine pinus ponderosa
Insect Molecular Biology, 2007Co-Authors: M L Erickson, Dezene P W Huber, Christian M Leutenegger, Joerg Bohlmann, Steven J. SeyboldAbstract:We have identified cDNAs and characterized the expression of 13 novel cytochrome P450 genes of potential importance in host colonization and reproduction by the California fivespined Ips, Ips paraconfusus. Twelve are of the Cyp4 family and one is of the Cyp9 family. Following feeding on host Pinus ponderosa phloem, bark beetle transcript levels of several of the Cyp4 genes increased or decreased in males only or in both sexes. In one instance (IparaCyp4A5) transcript accumulated significantly in females, but declined significantly in males. The Cyp9 gene (Cyp9T1) transcript levels in males were > 85 000 x higher at 8 h and > 25 000 x higher at 24 h after feeding compared with nonfed controls. Transcript levels in females were approximately 150 x higher at 24 h compared with nonfed controls. Cyp4G27 transcript was present constitutively regardless of sex or feeding and served as a better housekeeping gene than beta-actin or 18S rRNA for the real-time TaqMan polymerase chain reaction analysis. The expression patterns of Cyp4AY1, Cyp4BG1, and, especially, Cyp9T1 in males suggest roles for these genes in male-specific aggregation pheromone production. The differential transcript accumulation patterns of these bark beetle P450s provide insight into ecological interactions of I. paraconfusus with its host pines.
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Pine monoterpenes and pine bark beetles: a marriage of convenience for defense and chemical communication
Phytochemistry Reviews, 2006Co-Authors: Steven J. Seybold, Dezene P W Huber, Jana C. Lee, Andrew D. Graves, Jörg BohlmannAbstract:Pine-feeding bark beetles (Coleoptera: Scolytidae) interact chemically with their host pines (Coniferales: Pinaceae) via the behavioral, physiological, and biochemical effects of one class of isoprenoids, the monoterpenes and their derivatives. Pine monoterpenes occur in the oleoresin and function as behaviorally active kairomones for pine bark beetles and their predators, presenting a classic example of tri-trophic chemical communication. The monoterpenes are also essential co-attractants for pine bark beetle aggregation pheromones. Ironically, pine monoterpenes are also toxic physiologically to bark beetles at high vapor concentrations and are considered an important component of the defense of pines. Research over the last 30 years has demonstrated that some bark beetle aggregation pheromones arise through oxygenation of monoterpenes, linking pheromone biosynthesis to the host pines. Over the last 10 years, however, several frequently occurring oxygenated monoterpene pheromone components (e.g., Ipsenol, Ipsdienol and frontalin) have also been shown to arise through highly regulated de novo pathways in the beetles (reviewed in Seybold and Tittiger, 2003). The most interesting nexus between these insects and their plant hosts involves the late-stage reactions in the monoterpenoid biosynthetic pathway, during which isomeric dimethylallyl diphosphate and isopentenyl diphosphate are ultimately elaborated to stereospecific monoterpenes in the trees and to hydroxylated monoterpenes or bicyclic acetals in the insects. There is signal stereospecificity in both production of and response to the monoterpenoid aggregation pheromones of bark beetles and in response to␣the monoterpenes of the pines. In the California fivespined Ips, Ips paraconfusus, we have discovered a number of cytochome P450 genes that have expression patterns indicating that they may be involved in detoxifying monoterpene secondary metabolites and/or biosynthesizing pheromone components. Both processes result in the production of oxygenated monoterpenes, likely with varying degrees of stereospecificity. A behavioral analysis of the stereospecific response of I. paraconfusus to its pheromone is providing new insights into the development of an efficacious bait for the detection of this polyphagous insect in areas outside the western United States. In contrast, a Eurasian species that has arrived in California, the Mediterranean pine engraver, Orthotomicus (Ips) erosus, utilizes both a monoterpenoid (Ipsdienol) and a hemiterpenoid (2-methyl-3-buten-2-ol) in its pheromone blend. The stereospecificity of the response of O. erosus to the monoterpenoid appears to be the key factor to the improved potency of the attractant bait for this invasive species.
Gary J. Blomquist - One of the best experts on this subject based on the ideXlab platform.
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3.14 – Biochemistry and Molecular Biology of Pheromone Production
Reference Module in Life Sciences, 2017Co-Authors: Russell A Jurenka, Gary J. Blomquist, C. Schal, C. TittigerAbstract:The elucidation of the structure of the first insect sex pheromone, bombykol (( E , Z )-10,12-hexadecadien-1-ol) from the silkworm moth, Bombyx mori , spanned more than 20 years and required a half million female abdomens. A few years later, ( Z )-7-dodecenyl acetate was identified as the sex pheromone of the cabbage looper, Trichoplusia ni . At about the same time three terpenoid alcohols, Ipsenol, Ipsdienol, and verbenol were identified as the pheromone of the bark beetle, Ips paraconfusus . This latter finding led to the recognition that most insect pheromones consisted of multicomponent blends. This has since been shown to be true for most insects, while single component pheromones are rare. Rapid improvements in analytical instrumentation and techniques reduced the number of insects needed for pheromone extracts from a half million or more to where now individual insects can sometimes provide sufficient material for chemical analysis. Over the last five decades, extensive research on insect pheromones has resulted in the chemical and/or behavioral elucidation of pheromone components from well over 3000 insect species, with much of the work concentrating on sex pheromones from economically important pests. This chapter will provide an up to date analysis of the biochemistry and molecular biology of pheromone production in insects concentrating on sex pheromone production in moths, aggregation pheromones in bark beetles, and hydrocarbon pheromones in flies and cockroaches. The biosynthesis of select pheromone components will be presented as well as the hormonal regulation of pheromone production.
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Site of pheromone biosynthesis and isolation of HMG-CoA reductase cDNA in the cotton boll weevil, Anthonomus grandis
Archives of insect biochemistry and physiology, 2006Co-Authors: A. Huma Taban, Claus Tittiger, Jacob Blake, Ami Awano, Gary J. BlomquistAbstract:Isolated gut tissue from male cotton boll weevil, Anthonomus grandis (Coleoptera: Curculionidae), incorporated radiolabeled acetate into components that co-eluted with monoterpenoid pheromone components on HPLC. This demonstrates that pheromone components of male A. grandis are produced de novo and strongly suggests that pheromone biosynthesis occurs in gut tissue. A central enzyme in isoprenoid biosynthesis is 3-hydroxy-3-methylglutaryl-CoA reductase (HMG-R), and a full-length HMG-R cDNA was isolated from A. grandis. The predicted translation product was 54 and 45% identical to HMG-R from Ips paraconfusus and Drosophila melanogaster, respectively. HMG-R gene expression gradually increased with age in male A. grandis, which correlates with pheromone production. However, topical application of JH III did not significantly increase HMG-R mRNA levels.
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insect pheromones an overview of biosynthesis and endocrine regulation
Insect Biochemistry and Molecular Biology, 1999Co-Authors: Julie A Tillman, Steven J. Seybold, Russell A Jurenka, Gary J. BlomquistAbstract:This overview describes, compares, and attempts to unify major themes related to the biosynthetic pathways and endocrine regulation of insect pheromone production. Rather than developing and dedicating an entirely unique set of enzymes for pheromone biosynthesis, insects appear to have evolved to add one or a few tissue-specific auxiliary or modified enzymes that transform the products of “normal” metabolism to pheromone compounds of high stereochemical and quantitative specificity. This general understanding is derived from research on model species from one exopterygote insect order (Blattodea) and three endopterygote insect orders (Coleoptera, Diptera, and Lepidoptera). For instance, the ketone hydrocarbon contact sex pheromone of the female German cockroach, Blattella germanica, derives its origins from fatty acid biosynthesis, arising from elongation of a methyl-branched fatty acyl‐CoA moiety followed by decarboxylation, hydroxylation, and oxidation. Coleopteran sex and aggregation pheromones also arise from modifications of fatty acid biosynthesis or other biosynthetic pathways, such as the isoprenoid pathway (e.g. Cucujidae, Curculionidae, and Scolytidae), or from simple transformations of amino acids or other highly elaborated host precursors (e.g. Scarabaeidae and Scolytidae). Like the sex pheromone of B. germanica, female-produced dipteran (e.g. Drosophilidae and Muscidae) sex pheromone components originate from elongation of fatty acyl‐CoA moieties followed by loss of the carbonyl carbon and the formation of the corresponding hydrocarbon. Female-produced lepidopteran sex pheromones are also derived from fatty acids, but many moths utilize a species-specific combination of desaturation and chain-shortening reactions followed by reductive modification of the carbonyl carbon. Carbon skeletons derived from amino acids can also be used as chain initiating units and elongated to lepidopteran pheromones by this pathway (e.g. Arctiidae and Noctuidae). Insects utilize at least three hormonal messengers to regulate pheromone biosynthesis. Blattodean and coleopteran pheromone production is induced by juvenile hormone III (JH III). In the female common house fly, Musca domestica, and possibly other species of Diptera, it appears that during hydrocarbon sex pheromone biosynthesis, ovarian-produced ecdysteroids regulate synthesis by affecting the activities of one or more fatty acyl‐CoA elongation enzyme(s) (elongases). Lepidopteran sex pheromone biosynthesis is often mediated by a 33 or 34 amino acid pheromone biosynthesis activating neuropeptide (PBAN) through alteration of enzyme activities at one or more steps prior to or during fatty acid synthesis or during modification of the carbonyl group. Although a molecular level understanding of the regulation of insect pheromone biosynthesis is in its infancy, in the male California fivespined Ips, Ips paraconfusus (Coleoptera: Scolytidae), JH III acts at the transcriptional level by increasing the abundance of mRNA for 3-hydroxy-3-methylglutaryl-CoA reductase, a key enzyme in de novo isoprenoid aggregation pheromone biosynthesis. © 1999 Elsevier Science Ltd. All rights reserved.
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insect pheromones an overview of biosynthesis and endocrine regulation
Insect Biochemistry and Molecular Biology, 1999Co-Authors: Julie A Tillman, Steven J. Seybold, Russell A Jurenka, Gary J. BlomquistAbstract:Abstract This overview describes, compares, and attempts to unify major themes related to the biosynthetic pathways and endocrine regulation of insect pheromone production. Rather than developing and dedicating an entirely unique set of enzymes for pheromone biosynthesis, insects appear to have evolved to add one or a few tissue-specific auxiliary or modified enzymes that transform the products of “normal” metabolism to pheromone compounds of high stereochemical and quantitative specificity. This general understanding is derived from research on model species from one exopterygote insect order (Blattodea) and three endopterygote insect orders (Coleoptera, Diptera, and Lepidoptera). For instance, the ketone hydrocarbon contact sex pheromone of the female German cockroach, Blattella germanica, derives its origins from fatty acid biosynthesis, arising from elongation of a methyl-branched fatty acyl–CoA moiety followed by decarboxylation, hydroxylation, and oxidation. Coleopteran sex and aggregation pheromones also arise from modifications of fatty acid biosynthesis or other biosynthetic pathways, such as the isoprenoid pathway (e.g. Cucujidae, Curculionidae, and Scolytidae), or from simple transformations of amino acids or other highly elaborated host precursors (e.g. Scarabaeidae and Scolytidae). Like the sex pheromone of B. germanica, female-produced dipteran (e.g. Drosophilidae and Muscidae) sex pheromone components originate from elongation of fatty acyl–CoA moieties followed by loss of the carbonyl carbon and the formation of the corresponding hydrocarbon. Female-produced lepidopteran sex pheromones are also derived from fatty acids, but many moths utilize a species-specific combination of desaturation and chain-shortening reactions followed by reductive modification of the carbonyl carbon. Carbon skeletons derived from amino acids can also be used as chain initiating units and elongated to lepidopteran pheromones by this pathway (e.g. Arctiidae and Noctuidae). Insects utilize at least three hormonal messengers to regulate pheromone biosynthesis. Blattodean and coleopteran pheromone production is induced by juvenile hormone III (JH III). In the female common house fly, Musca domestica, and possibly other species of Diptera, it appears that during hydrocarbon sex pheromone biosynthesis, ovarian-produced ecdysteroids regulate synthesis by affecting the activities of one or more fatty acyl–CoA elongation enzyme(s) (elongases). Lepidopteran sex pheromone biosynthesis is often mediated by a 33 or 34 amino acid pheromone biosynthesis activating neuropeptide (PBAN) through alteration of enzyme activities at one or more steps prior to or during fatty acid synthesis or during modification of the carbonyl group. Although a molecular level understanding of the regulation of insect pheromone biosynthesis is in its infancy, in the male California fivespined Ips, Ips paraconfusus (Coleoptera: Scolytidae), JH III acts at the transcriptional level by increasing the abundance of mRNA for 3-hydroxy-3-methylglutaryl-CoA reductase, a key enzyme in de novo isoprenoid aggregation pheromone biosynthesis.
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Insect pheromones—an overview of biosynthesis and endocrine regulation
Insect biochemistry and molecular biology, 1999Co-Authors: Julie A Tillman, Steven J. Seybold, Russell A Jurenka, Gary J. BlomquistAbstract:Abstract This overview describes, compares, and attempts to unify major themes related to the biosynthetic pathways and endocrine regulation of insect pheromone production. Rather than developing and dedicating an entirely unique set of enzymes for pheromone biosynthesis, insects appear to have evolved to add one or a few tissue-specific auxiliary or modified enzymes that transform the products of “normal” metabolism to pheromone compounds of high stereochemical and quantitative specificity. This general understanding is derived from research on model species from one exopterygote insect order (Blattodea) and three endopterygote insect orders (Coleoptera, Diptera, and Lepidoptera). For instance, the ketone hydrocarbon contact sex pheromone of the female German cockroach, Blattella germanica, derives its origins from fatty acid biosynthesis, arising from elongation of a methyl-branched fatty acyl–CoA moiety followed by decarboxylation, hydroxylation, and oxidation. Coleopteran sex and aggregation pheromones also arise from modifications of fatty acid biosynthesis or other biosynthetic pathways, such as the isoprenoid pathway (e.g. Cucujidae, Curculionidae, and Scolytidae), or from simple transformations of amino acids or other highly elaborated host precursors (e.g. Scarabaeidae and Scolytidae). Like the sex pheromone of B. germanica, female-produced dipteran (e.g. Drosophilidae and Muscidae) sex pheromone components originate from elongation of fatty acyl–CoA moieties followed by loss of the carbonyl carbon and the formation of the corresponding hydrocarbon. Female-produced lepidopteran sex pheromones are also derived from fatty acids, but many moths utilize a species-specific combination of desaturation and chain-shortening reactions followed by reductive modification of the carbonyl carbon. Carbon skeletons derived from amino acids can also be used as chain initiating units and elongated to lepidopteran pheromones by this pathway (e.g. Arctiidae and Noctuidae). Insects utilize at least three hormonal messengers to regulate pheromone biosynthesis. Blattodean and coleopteran pheromone production is induced by juvenile hormone III (JH III). In the female common house fly, Musca domestica, and possibly other species of Diptera, it appears that during hydrocarbon sex pheromone biosynthesis, ovarian-produced ecdysteroids regulate synthesis by affecting the activities of one or more fatty acyl–CoA elongation enzyme(s) (elongases). Lepidopteran sex pheromone biosynthesis is often mediated by a 33 or 34 amino acid pheromone biosynthesis activating neuropeptide (PBAN) through alteration of enzyme activities at one or more steps prior to or during fatty acid synthesis or during modification of the carbonyl group. Although a molecular level understanding of the regulation of insect pheromone biosynthesis is in its infancy, in the male California fivespined Ips, Ips paraconfusus (Coleoptera: Scolytidae), JH III acts at the transcriptional level by increasing the abundance of mRNA for 3-hydroxy-3-methylglutaryl-CoA reductase, a key enzyme in de novo isoprenoid aggregation pheromone biosynthesis.
Thomas R. Gordon - One of the best experts on this subject based on the ideXlab platform.
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feeding response of Ips paraconfusus to phloem and phloem metabolites of heterobasidion annosum inoculated ponderosa pine pinus ponderosa
Journal of Chemical Ecology, 2003Co-Authors: William R Mcnee, David L Wood, Andrew J. Storer, Pierluigi Bonello, Thomas R. GordonAbstract:In studies of feeding by the bark beetle, Ips paraconfusus, two pine stilbenes (pinosylvin and pinosylvin methyl ether), ferulic acid glucoside, and enantiomers of the four most common sugars present in ponderosa pine phloem (sucrose, glucose, fructose, and raffinose) did not stimulate or reduce male feeding when assayed on wet α-cellulose with or without stimulatory phloem extractives present. When allowed to feed on wet α-cellulose containing sequential extracts (hexane, methanol, and water) of ponderosa pine phloem, methanol and water extractives stimulated feeding, but hexane extractives did not. Males confined in wet α-cellulose containing aqueous or organic extracts of culture broths derived from phloem tissue and containing the root pathogen, Heterobasidion annosum, ingested less substrate than beetles confined to control preparations. In an assay using logs from uninoculated ponderosa pines, the mean lengths of phloem in the digestive tracts increased as time spent feeding increased. Males confined to the phloem of basal logs cut from ponderosa pines artificially inoculated with H. annosum ingested significantly less phloem than beetles in logs cut from trees that were (combined) mock-inoculated or uninoculated and did not contain the pathogen. However, individual pathogen-containing treatments were not significantly different from uninoculated controls. It was concluded that altered feeding rates are not a major factor which may explain why diseased ponderosa pines are colonized by I. paraconfusus.
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Effects of pitch canker pathogen on gallery excavation and oviposition by Ips paraconfusus (Coleoptera: Scolytidae)
The Canadian Entomologist, 2002Co-Authors: Andrew J. Storer, David L Wood, Thomas R. GordonAbstract:Ips paraconfusus Lanier est un vecteur du champignon pathogene qui cause le chancre fusarien du pin, Fusarium circinatum Nirenberg et O'Donnell, en Californie. Les infections multiples sur les branches et les rameaux principaux du pin de Monterey, Pinus radiata D. Don. (Pinaceae), semblent predisposer les arbres aux infestations d'I. paraconfusus. La presence des chancres apparus en reaction au pathogene affectent apparemment la ponte et la construction de tunnels. Les scolytes introduits dans des chancres naturels et des chancres provoques artificiellement ont moins de chances de pondre que les scolytes introduits dans des troncs sains et leurs tunnels sont plus courts. Chez tous les adultes qui produisent des oeufs, le nombre moyen d'oeufs par adulte est le meme dans les troncs sains et dans les troncs malades; cependant, la distance entre le point de transmission de la maladie et le premier oeuf, mesuree perpendiculairement au grain du bois, est plus grande chez les adultes introduits dans les chancres que chez ceux qui sont inseres loin des chancres. Ces resultats indiquent que le pathogene responsable du chancre fusarien du pin a un effet negatif sur I. paraconfusus parce que les chancres apparus en reaction au pathogene ne peuvent etre exploites par le scolyte.
