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Sample records for juvenile hormone influence

  1. THE INFLUENCE OF INSECT JUVENILE HORMONE AGONISTTS ON METAMORPHOSIS AND REPRODUCTION IN ESTUARINE CRUSTACEANS

    EPA Science Inventory

    Comparative developmental and reproductive studies were performed on several species of estuarine crustaceans in response to three juvenile hormone agonists (JHAs) (methoprene, fenoxycarb, and pyriproxyfen). Larval development of the grass shrimp, Palaemonetes pugio, was greater ...

  2. THE INFLUENCE OF INSECT JUVENILE HORMONE AGONISTTS ON METAMORPHOSIS AND REPRODUCTION IN ESTUARINE CRUSTACEANS

    EPA Science Inventory

    Comparative developmental and reproductive studies were performed on several species of estuarine crustaceans in response to three juvenile hormone agonists (JHAs) (methoprene, fenoxycarb, and pyriproxyfen). Larval development of the grass shrimp, Palaemonetes pugio, was greater ...

  3. The influence of insect juvenile hormone agonists on metamorphosis and reproduction in estuarine crustaceans.

    PubMed

    McKenney, Charles L

    2005-01-01

    Comparative developmental and reproductive studies were performed on several species of estuarine crustaceans in response to three juvenile hormone agonists (pyriproxyfen, methoprene and fenoxycarb). Larval development of the grass shrimp, Palaemonetes pugio, was greater than two orders of magnitude more sensitive to disruption by methoprene and fenoxycarb than was embryonic development. Developing larvae of the mud crab, Rhithropanopeus harrisii, exhibited reduced metamorphic success at lower concentrations of methoprene and pyriproxyfen than grass shrimp larvae. These responses suggest that the more rigidly controlled metamorphic process in crabs is more sensitive to compounds acting as endocrine disruptors than is the more flexible metamorphic pattern in shrimp. The final crab larval stage, the megalopa, was more sensitive to methoprene and fenoxycarb exposure than earlier zoeal stages. Mud crab larvae exposed to fenoxycarb had reduced biomass and lipid content, particularly triglycerides and sterols. Concentrations of fenoxycarb which reduced the reproductive capacity in single life-cycle exposures of the estuarine mysid, Americamysis bahia, were similar to those concentrations which inhibited metamorphosis in grass shrimp. Juvenile mysids released by exposed adults and reared through maturation without further exposure produced fewer young and had altered sex ratios (lower percentages of males) at lower parental-exposure concentrations than directly affected parental reproduction. These transgenerational responses may well be a product of irreversible effects during developmental exposures which become apparent following maturation and initiation of reproduction. These findings support using a functional approach as an appropriate screening procedure to evaluate potential environmental endocrine-disrupting chemicals in aquatic environments.

  4. Influence of juvenile hormone and mating on oogenesis and oviposition in the codling moth, cydia pomonella

    PubMed

    Webb; Shu; Ramaswamy; Dorn

    1999-01-01

    Oogenesis in the codling moth, Cydia pomonella, and the role of juvenile hormones (JHs) were addressed. Rudimentary ovarian structures were recognisable in day 3-4 pupae, when haemolymph JH was still undetectable by coupled gas chromatography-mass spectrometry in the selected ion mode (GC-MS/SIM). The presence of developing oocytes was observed by light microscopy on day 8, coincident with very low JH titres (0.74 +/- 0.05 ng/ml JH II). Chorionation was only evident upon emergence, following an increase in JH in the pharate adult (0h old: 4.71 +/- 0.34 ng/ml JH II). Analysis of haemolymph from virgin and mated females indicated that JH II was predominant, with approximately equal and lower quantities of JHs I and III (3.3- to 5.0-fold less). When pupae or newly emerged adults were treated with JH homologues, no alteration in ovarian protein content was apparent, but the JH mimetic, fenoxycarb, depressed the number of oocytes filling >/= 50% follicular volume. Chorion deposition was stimulated by JHs I, II, or III (10 &mgr;g), but not by fenoxycarb (0.05 &mgr;g, 10 &mgr;g). Mating provided correct stimuli for enhanced choriogenesis and egg laying, and, since haemolymph JH titres were concomitantly elevated (approximately 2-fold), it was postulated that the rise in JH elicited both these events. Application of JHs to virgin females, however, could not mimic mating; only increases in choriogenesis were induced: JH-treatment of virgins (or mated insects) significantly decreased oviposition rates over 24 and 48 h and markedly reduced the life-time total number of eggs. Arch. Copyright 1999 Wiley-Liss, Inc.

  5. Influence of the juvenile hormone analogue, methoprene, on development of the southern pine beetle, Dendroctonus frontalis Zimm. (Col. Scolytidae)

    Treesearch

    J.W. Van Sambeek; J.R. Bridges

    1980-01-01

    To determine the effects of juvenoids on the development and sensitivity of the southern pine beetle (SPB) Dendroctonus frontalis Zimm, we treated last-instar larvae, pupae, and callow adults with methoprene, a potent juvenile hormone analogue. From this study we identified a number of juvenoid effects on SPB. Methoprene has the greatest effect on...

  6. Light exposure leads to reorganization of microglomeruli in the mushroom bodies and influences juvenile hormone levels in the honeybee.

    PubMed

    Scholl, Christina; Wang, Ying; Krischke, Markus; Mueller, Martin J; Amdam, Gro V; Rössler, Wolfgang

    2014-11-01

    Honeybees show a remarkable behavioral plasticity at the transition from nursing inside the hive to foraging for nectar and/or pollen outside. This plasticity is important for age-related division of labor in honeybee colonies. The behavioral transition is associated with significant volume and synaptic changes in the mushroom bodies (MBs), brain centers for sensory integration, learning, and memory. We tested whether precocious sensory exposure to light leads to changes in the density of synaptic complexes [microglomeruli (MG)] in the MBs. The results show that exposure to light pulses over 3 days induces a significant decrease in the MG density in visual subregions (collar) of the MB. Earlier studies had shown that foragers have increased levels of juvenile hormone (JH) co-occurring with a decrease of vitellogenin (Vg). Previous work further established that RNAi-mediated knockdown of vg and ultraspiracle (usp) induced an upregulation of JH levels, which can lead to precocious foraging. By disturbing both Vg and JH pathways using gene knockdown of vg and usp, we tested whether the changes in the hormonal system directly affect MG densities. Our study shows that MG numbers remained unchanged when Vg and JH pathways were perturbed, suggesting no direct hormonal influences on MG densities. However, mass spectrometry detection of JH revealed that precocious light exposure triggered an increase in JH levels in the hemolymph (HL) of young bees. This suggests a dual effect following light exposure via direct effects on MG reorganization in the MB calyx and a possible positive feedback on HL JH levels.

  7. Juvenile hormone regulation of Drosophila aging

    PubMed Central

    2013-01-01

    Background Juvenile hormone (JH) has been demonstrated to control adult lifespan in a number of non-model insects where surgical removal of the corpora allata eliminates the hormone’s source. In contrast, little is known about how juvenile hormone affects adult Drosophila melanogaster. Previous work suggests that insulin signaling may modulate Drosophila aging in part through its impact on juvenile hormone titer, but no data yet address whether reduction of juvenile hormone is sufficient to control Drosophila life span. Here we adapt a genetic approach to knock out the corpora allata in adult Drosophila melanogaster and characterize adult life history phenotypes produced by reduction of juvenile hormone. With this system we test potential explanations for how juvenile hormone modulates aging. Results A tissue specific driver inducing an inhibitor of a protein phosphatase was used to ablate the corpora allata while permitting normal development of adult flies. Corpora allata knockout adults had greatly reduced fecundity, inhibited oogenesis, impaired adult fat body development and extended lifespan. Treating these adults with the juvenile hormone analog methoprene restored all traits toward wildtype. Knockout females remained relatively long-lived even when crossed into a genotype that blocked all egg production. Dietary restriction further extended the lifespan of knockout females. In an analysis of expression profiles of knockout females in fertile and sterile backgrounds, about 100 genes changed in response to loss of juvenile hormone independent of reproductive state. Conclusions Reduced juvenile hormone alone is sufficient to extend the lifespan of Drosophila melanogaster. Reduced juvenile hormone limits reproduction by inhibiting the production of yolked eggs, and this may arise because juvenile hormone is required for the post-eclosion development of the vitellogenin-producing adult fat body. Our data do not support a mechanism for juvenile hormone control

  8. Influence of age and juvenile hormone on brain dopamine level in male honeybee (Apis mellifera): association with reproductive maturation.

    PubMed

    Harano, Ken-ichi; Sasaki, Ken; Nagao, Takashi; Sasaki, Masami

    2008-05-01

    Dopamine (DA) is a major functional biogenic amine in insects and has been suggested to regulate reproduction in female honeybees. However, its function has not been investigated in male drones. To clarify developmental changes of DA in drones, brain DA levels were investigated at various ages and showed a similar pattern to the previously reported juvenile hormone (JH) hemolymph titer. The DA level was lowest at emergence and peaked at day 7 or 8, followed by decline. Application of JH analog increased brain DA levels in young drones (2-4-days-old), suggesting regulation of DA by JH in drones. In young drones, maturation of male reproductive organs closely matched the increase in brain DA. The dry weight of testes decreased and that of seminal vesicles increased from emergence to day 8. The dry weight of mucus glands increased up to day 4. Consequently, DA regulated by JH might have reproductive behavior and/or physiological functions in drones.

  9. Behavioural effects of juvenile hormone and their influence on division of labour in leaf-cutting ant societies.

    PubMed

    Norman, Victoria C; Hughes, William O H

    2016-01-01

    Division of labour in social insects represents a major evolutionary transition, but the physiological mechanisms that regulate this are still little understood. Experimental work with honey bees, and correlational analyses in other social insects, have implicated juvenile hormone (JH) as a regulatory factor, but direct experimental evidence of behavioural effects of JH in social insects is generally lacking. Here, we used experimental manipulation of JH to show that raised JH levels in leaf-cutting ants results in workers becoming more active, phototactic and threat responsive, and engaging in more extranidal activity - behavioural changes that we show are all characteristic of the transition from intranidal work to foraging. These behavioural effects on division of labour suggest that the JH mediation of behaviour occurs across multiple independent evolutions of eusociality, and may be a key endocrine regulator of the division of labour which has produced the remarkable ecological and evolutionary success of social insects.

  10. Seasonal changes in juvenile hormone titers and rates of biosynthesis in honey bees.

    PubMed

    Huang, Z Y; Robinson, G E

    1995-01-01

    Honey bee colonies can respond to changing environmental conditions by showing plasticity in age related division of labor, and these responses are associated with changes in juvenile hormone. The shift from nest tasks to foraging has been especially well characterized; foraging is associated with high juvenile hormone titers and high rates of juvenile hormone biosynthesis, and can be induced prematurely in young bees by juvenile hormone treatment or by a shortage of foragers. However, very few studies have been conducted that study plasticity in division of labor under naturally occurring changes in the environment. To gain further insight into how the environment and juvenile hormone influence foraging behavior, we measured juvenile hormone titers and rates of biosynthesis in workers during times of the year when colony activity in temperature climates is reduced: late fall, winter, and early spring. Juvenile hormone titers and rates of biosynthesis decreased in foragers in the fall as foraging diminished and bees became less active. This demonstration of a natural drop in juvenile hormone confirms and extends previous findings when bees were experimentally induced to revert from foraging to within-hive tasks. In addition, endocrine changes in foragers in the fall are part of a larger seasonally related phenomenon in which juvenile hormone levels in younger, pre-foraging bees also decline in the fall and then increase the following spring as colony activity increases. The seasonal decline in juvenile hormone in foragers was mimicked in summer by placing a honey bee colony in a cold room for 8 days. This suggests that seasonal changes in juvenile hormone are not related to photoperiod changes, but rather to changes in temperature and/or colony social structure that in turn influence endocrine and behavioral development. We also found that active foragers in the late winter and early spring had lower juvenile hormone levels than active foragers in late spring. In

  11. Seasonal variation in plasma thyroid hormone concentrations in coastal versus inland populations of juvenile American alligators (Alligator mississippiensis): influence of plasma iodide concentrations.

    PubMed

    Boggs, Ashley S P; Hamlin, Heather J; Lowers, Russell H; Guillette, Louis J

    2011-12-01

    Thyroid hormones, essential for normal growth and health, are associated with changes in temperature, photoperiod, and reproduction. Iodide, a necessary element for thyroid hormone production, varies in diet, and is more abundant in estuarine environments, which could alter thyroid hormone variation. However, associations between thyroid hormone concentrations in animals from marine versus freshwater environments, which could become more pertinent with rising sea levels associated with global climate change, are not well studied. To determine the importance of dietary iodide in seasonal variation of plasma thyroid hormone concentrations, we analyzed seasonal variation of plasma thyroxine (T(4)) and triiodothyronine (T(3)) concentrations in juvenile alligators from an estuarine habitat (Merritt Island National Wildlife Refuge; MI) and a freshwater habitat (Lake Woodruff National Wildlife Refuge; LW) and compared these results to plasma inorganic iodide (PII) concentrations. Alligators from MI did not display seasonal variation in plasma T(4), but exhibited a seasonal pattern in plasma T(3) concentrations similar to alligators from LW. Plasma thyroid hormone concentrations were consistently higher at MI than at LW. PII concentrations were correlated with plasma T(4) and T(3) concentrations in juvenile alligators from LW but not MI. The data on plasma T(4) and T(3) concentrations suggest altered iodide metabolism in estuarine alligators. Differences in thyroid hormone concentrations between the populations could be due to differences in dietary iodide, which need to be further evaluated. Copyright © 2011 Elsevier Inc. All rights reserved.

  12. Juvenile hormone esterase: biochemistry and structure

    PubMed Central

    Kamita, Shizuo G.; Hammock, Bruce D.

    2013-01-01

    Synopsis Normal insect development requires a precisely timed, precipitous drop in hemolymph juvenile hormone (JH) titer. This drop occurs through a coordinated halt in JH biosynthesis and increase in JH metabolism. In many species, JH esterase (JHE) is critical for metabolism of the resonance-stabilized methyl ester of JH. JHE metabolizes JH with a high kcat/KM ratio that results primarily from an exceptionally low KM. Here we review the biochemistry and structure of authentic and recombinant JHEs from six insect orders, and present updated diagnostic criteria that help to distinguish JHEs from other carboxylesterases. The use of a JHE-encoding gene to improve the insecticidal efficacy of biopesticides is also discussed. PMID:23543805

  13. Comparative genomics of insect juvenile hormone biosynthesis⋆

    PubMed Central

    Noriega, F.G.; Ribeiro, J.M.C.; Koener, J.F.; Valenzuela, J.G.; Hernandez-Martinez, S.; Pham, V.M.; Feyereisen, R.

    2009-01-01

    The biosynthesis of insect juvenile hormone (JH) and its neuroendocrine control are attractive targets for chemical control of insect pests and vectors of disease. To facilitate the molecular study of JH biosynthesis, we analyzed ESTs from the glands producing JH, the corpora allata (CA) in the cockroach Diploptera punctata, an insect long used as a physiological model species and compared them with ESTs from the CA of the mosquitoes Aedes aegypti and Anopheles albimanus. The predicted genes were analyzed according to their probable functions with the Gene Ontology classification, and compared to Drosophila and Anopheles gambiae genes. A large number of reciprocal matches in the cDNA libraries of cockroach and mosquito CA were found. These matches defined known and suspected enzymes of the JH biosynthetic pathway, but also several proteins associated with signal transduction that might play a role in the modulation of JH synthesis by neuropeptides. The identification in both cockroach and mosquito CA of homologs of the small ligand binding proteins from insects, Takeout/JH binding protein and retinol-binding protein highlights a hitherto unsuspected complexity of metabolite trafficking, perhaps JH precursor trafficking, in these endocrine glands. Furthermore, many reciprocal matches for genes of unknown function may provide a fertile ground for an in-depth study of allatal-specific cell physiology. PMID:16551550

  14. Aedes aegypti juvenile hormone acid methyl transferase, the ultimate enzyme in the biosynthetic pathway of juvenile hormone III, exhibits substrate control

    USDA-ARS?s Scientific Manuscript database

    We report on the cloning, sequencing, characterization, 3D modeling and docking of Aedes aegypti juvenile hormone acid methyl transferase (AeaJHAMT), the enzyme that converts juvenile hormone acid (JHA) into juvenile hormone (JH). Purified recombinant AeaJHAMT was extensively characterized for enzym...

  15. The synthesis of insect juvenile hormones and their analogues

    NASA Astrophysics Data System (ADS)

    Odinokov, Viktor N.; Kukovinets, Olga S.; Zainullin, R. A.; Tolstikov, Genrikh A.

    1992-07-01

    The methods of synthesis of insect juvenile hormones and their natural and synthetic analogues (juvenoids) are considered. Much attention is paid to juvenoids of the 2,4-dienoate class, including oxa and aza derivatives and cyclic and heterocyclic compounds, which display selective activity towards vairous forms of insect. The bibliography includes 263 references.

  16. Juvenile hormone agonists affect the occurrence of male Daphnia.

    PubMed

    Tatarazako, Norihisa; Oda, Shigeto; Watanabe, Hajime; Morita, Masatoshi; Iguchi, Taisen

    2003-12-01

    The water flea Daphnia magna reproduces primarily by cyclic parthenogenesis. Environmental stimuli that signal a change to adverse conditions induce the organisms to switch from parthenogenesis to gamogenetic reproduction. During the gamogenetic period, they produce male daphnids and dormant resting eggs, which can survive prolonged periods of environmental adversity. However, little is known about the mechanisms associated with the switch from parthenogenesis to gamogenetic reproduction. We investigated the effects of several juvenoids on sex determination in Daphnia. Females less than 24 h old were exposed to various concentrations of the test substance and were observed for 21 days. It was found that they can trigger the appearance of male daphnids: the percentage of males in the population increases to a level greater than what occurs under ordinary environmental conditions. We found that methylfarnesoate, juvenile hormone III, methoprene, and the phenoxyphenoxy derivatives pyriproxyfen and fenoxycarb (both insecticides) reduced the production of offspring and produced sex ratios dominated by male daphnids. Pyriproxyfen and fenoxycarb showed striking effects at low concentrations. Exposure to either of these chemicals at a concentration of 330 ngl(-1) caused adult females to produce almost all male neonates. Methylfarnesoate, juvenile hormone III, and methoprene showed an effect in inducing male production at higher concentrations (3.7 x 10(3), 3.3 x 10(5), and 1.3 x 10(5) ngl(-1), respectively). Our findings suggest that juvenile hormone agonists, including some insecticides, affect the chemical signaling responsible for inducing the production of male offspring.

  17. Juvenile hormone regulation of longevity in the migratory monarch butterfly.

    PubMed

    Herman, W S; Tatar, M

    2001-12-22

    Monarch butterflies (Danaus plexippus) of eastern North America are well known for their long-range migration to overwintering roosts in south-central Mexico. An essential feature of this migration involves the exceptional longevity of the migrant adults; individuals persist from August/September to March while their summer counterparts are likely to live less than two months as adults. Migrant adults persist during a state of reproductive diapause in which both male and female reproductive development is arrested as a consequence of suppressed synthesis of juvenile hormone. Here, we describe survival in monarch butterflies as a function of the migrant syndrome. We show that migrant adults are longer lived than summer adults when each are maintained under standard laboratory conditions, that the longevity of migrant adults is curtailed by treatment with juvenile hormone and that the longevity of summer adults is increased by 100% when juvenile hormone synthesis is prevented by surgical removal of its source, the corpora allatum. Thus, monarch butterfly persistence through a long winter season is ensured in part by reduced ageing that is under endocrine regulation, as well as by the unique environmental properties of their winter roost sites. Phenotypic plasticity for ageing is an integral component of the monarch butterflies' migration-diapause syndrome.

  18. Larval feeding substrate and species significantly influence the effect of a juvenile hormone analog on sexual development/performance in four tropical tephritid flies.

    PubMed

    Aluja, Martín; Ordano, Mariano; Teal, Peter E A; Sivinski, John; García-Medel, Darío; Anzures-Dadda, Alberto

    2009-03-01

    The juvenile hormone (JH) analog methoprene reduces the amount of time it takes laboratory-reared Anastrepha suspensa (Caribbean fruit fly) males to reach sexual maturity by almost half. Here, we examined if methoprene exerted a similar effect on four other tropical Anastrepha species (Anastrepha ludens, Anastrepha obliqua, Anastrepha serpentina and Anastrepha striata) reared on natural hosts and exhibiting contrasting life histories. In the case of A. ludens, we worked with two populations that derived from Casimiroa greggii (ancestral host, larvae feed on seeds) and Citrus paradisi (exotic host, larvae feed on pulp). We found that the effects of methoprene, when they occurred, varied according to species and, in the case of A. ludens, according to larval host. For example, in the case of the two A. ludens populations the effect of methoprene on first appearance of male calling behavior and number of copulations was only apparent in flies derived from C. greggii. In contrast, males derived from C. paradisi called and mated almost twice as often and females started to lay eggs almost 1 day earlier than individuals derived from C. greggii, but in this case there was no significant effect of treatment (methoprene) only a significant host effect. There were also significant host and host by treatment interactions with respect to egg clutch size. A. ludens females derived from C. paradisi laid significantly more eggs per clutch and total number of eggs than females derived from C. greggii. With respect to the multiple species comparisons, the treatment effect was consistent for A. ludens, occasional in A. serpentina (e.g., calling by males, clutch size), and not apparent in the cases of A. obliqua and A. striata. Interestingly, with respect to clutch size, in the cases of A. ludens and A. serpentina, the treatment effect followed opposite directions: positive in the case of A. ludens and negative in the case of A. serpentina. We center our discussion on two hypotheses

  19. Juvenile Hormone Titer Versus Juvenile Hormone Synthesis in Female Nymphs and Adults of the German Cockroach, Blattella germanica

    PubMed Central

    Treiblmayr, Karl; Pascual, Nuria; Piulachs, Maria-Dolors; Keller, Thomas; Belles, Xavier

    2006-01-01

    Patterns of juvenile hormone have been intensively studied in the cockroach Blattella germanica under different physiological situations. However, data have been mainly obtained in vitro, and refer to hormone synthesized by isolated corpora allata, whereas information available on hormone concentration in the hemolymph is restricted to adult females. In order to complement our studies in vitro, we have measured juvenile hormone titer in the hemolymph of B. germanica females in four characteristic physiological situations: penultimate and last instar nymphs, adults during the first vitellogenic cycle, and adults transporting egg cases (ootheca). In general, a significant positive correlation between rates of hormone synthesis and concentration in the hemolymph is observed. The main disparities appear in the penultimate day of the period of ootheca transport, where titer is high whereas synthesis is low, and on day 6 of the first vitellogenic cycle, where synthesis increases whereas titer decreases. At these stages, the observed disparities between synthesis and titer might be explained by differential action of degradation enzymes. PMID:20233097

  20. Modeling resistance to juvenile hormone analogs: linking evolution, ecology and management

    USDA-ARS?s Scientific Manuscript database

    Juvenile hormone analogs (JHAs) are insecticides that mimic insect juvenile hormone and interfere with normal insect development. JHAs disrupt a hormonal system that is specific to insects and thus kill some target pests while causing little or no harm to most non-target organisms. Because of thei...

  1. Isolation and characterization of juvenile hormone esterase from gypsy moth (Lymantria dispar)

    Treesearch

    Algimantas P. Valaitis; Joan Jolliff

    1991-01-01

    Insect metamorphosis is under precise hormonal control. During the last larval stadium, the degradation of juvenile hormone by juvenile hormone esterase (JHE) is essential for the initiation of pupation. Therefore, we have targeted this system for disruption with a strategy to produce a recombinant gypsy moth virus which expresses JHE. In order to clone and insert the...

  2. The effects of juvenile hormone on Lasius niger reproduction.

    PubMed

    Pamminger, T; Buttstedt, A; Norman, V; Schierhorn, A; Botías, C; Jones, J C; Basley, K; Hughes, W O H

    2016-12-01

    Reproduction has been shown to be costly for survival in a wide diversity of taxa. The resulting trade-off, termed the reproduction-survival trade-off, is thought to be one of the most fundamental forces of life-history evolution. In insects the pleiotropic effect of juvenile hormone (JH), antagonistically regulating reproduction and pathogen resistance, is suggested to underlie this phenomenon. In contrast to the majority of insects, reproductive individuals in many eusocial insects defy this trade-off and live both long and prosper. By remodelling the gonadotropic effects of JH in reproductive regulation, the queens of the long-lived black garden ant Lasius niger (living up to 27 years), have circumvented the reproduction-survival trade off enabling them to maximize both reproduction and pathogen resistance simultaneously. In this study we measure fertility, vitellogenin gene expression and protein levels after experimental manipulation of hormone levels. We use these measurements to investigate the mechanistic basis of endocrinological role remodelling in reproduction and determine how JH suppresses reproduction in this species, rather then stimulating it, like in the majority of insects. We find that JH likely inhibits three key aspects of reproduction both during vitellogenesis and oogenesis, including two previously unknown mechanisms. In addition, we document that juvenile hormone, as in the majority of insects, has retained some stimulatory function in regulating vitellogenin expression. We discuss the evolutionary consequences of this complex regulatory architecture of reproduction in L. niger, which might enable the evolution of similar reproductive phenotypes by alternate regulatory pathways, and the surprising flexibility regulatory role of juvenile hormone in this process. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Ecdysteroids, Juvenile Hormone and Vitellogenesis in the Cockroach Leucophaea maderae.

    PubMed Central

    Engelmann, Franz

    2002-01-01

    Topical application of 400µg of the juvenile hormone analog, methoprene, to females of the penultimate instar of Leucophaea maderae failed to induce vitellogenin synthesis. However, last instar females showed an increasing response level in making vitellogenin as they aged during the first half of the instar. In the second half of the last instar the response to methoprene declined to nearly zero when the prothoracic glands have become highly active. Then, a few days before the metamorphic molt the responsiveness reached maximal levels, i.e., comparable to adult females. These data suggest that the fat body develops competency to produce vitellogenin during the last nymphal instar, but increasing titers of ecdysone then interfere with the action of methoprene and consequently production of vitellogenin is curtailed. When prothoracic glands from the second half of the last instar were implanted into adult females, the normal activation of the corpora allata, or their accelerated activation induced by mating, did not occur. Likewise, an activation of the corpora allata due to the severance of the NCCI was not observed when prothoracic glands had been implanted prior to such operations. Thus, ecdysone released by the prothoracic glands appeared to directly inhibit the isolated corpora allata in vivo i.e. without the mediation by the brain. Methoprene applied to allatectomized adult females induced vitellogenin synthesis in a dose dependent manner. This induction was, however, quantitatively reduced by implanted active prothoracic glands, particularly when low doses of methoprene had been applied. Methoprene higher than 5µg overcame the inhibitory potency of the implanted prothoracic glands. The effect of the prothoracic glands, i.e. ecdysone, appears to signal an interference with the action of methoprene at the target tissues, the fat body. The exposure of the fat body to a given juvenile hormone/ecdysone ratio dictates the apparent effectiveness of ecdysone. The

  4. Juvenile hormone diol kinase. I. Purification, characterization, and substrate specificity of juvenile hormone-selective diol kinase from Manduca sexta.

    PubMed

    Maxwell, Robert A; Welch, William H; Schooley, David A

    2002-06-14

    Manduca sexta juvenile hormone diol kinase (JHDK) catalyzes the conversion of juvenile hormone (JH) diol to JH diol phosphate. JHDK may be the first example of a phosphotransferase directly involved in the catabolism and inactivation of a lipid-soluble hormone. JHDK is an enzyme crucial for secondary metabolism of JH and possesses high specificity and catalytic efficiency for JH diol. In this study, the purification and characterization of native JHDK are described; its enzymatic properties are examined; and its role in cellular JH metabolism is explored. Using a variety of potential substrates, we show that JHDK has a preference for ATP, but will catalyze the formation of JH diol phosphate with GTP as the phosphate donor. JHDK has a nanomolar K(m) for JH I diol and a low micromolar value for MgATP. JH II and III diols also serve as phosphate acceptors with low micromolar K(m), whereas other diol derivatives of terpenoid esters structurally similar to JH metabolites are not phosphorylated. The reaction proceeds via a sequential Bi Bi mechanism. JHDK is active as a homodimer with a subunit molecular mass of 20 kDa. JHDK binds 5'-p-fluorosulfonylbenzoyladenosine and is inhibited by micromolar levels of Ca2+.

  5. Vitellogenin, juvenile hormone, insulin signaling, and queen honey bee longevity

    PubMed Central

    Corona, Miguel; Velarde, Rodrigo A.; Remolina, Silvia; Moran-Lauter, Adrienne; Wang, Ying; Hughes, Kimberly A.; Robinson, Gene E.

    2007-01-01

    In most animals, longevity is achieved at the expense of fertility, but queen honey bees do not show this tradeoff. Queens are both long-lived and fertile, whereas workers, derived from the same genome, are both relatively short-lived and normally sterile. It has been suggested, on the basis of results from workers, that vitellogenin (Vg), best known as a yolk protein synthesized in the abdominal fat body, acts as an antioxidant to promote longevity in queen bees. We explored this hypothesis, as well as related roles of insulin–IGF-1 signaling and juvenile hormone. Vg was expressed in thorax and head fat body cells in an age-dependent manner, with old queens showing much higher expression than workers. In contrast, Vg expression in worker head was much lower. Queens also were more resistant to oxidative stress than workers. These results support the hypothesis that caste-specific differences in Vg expression are involved in queen longevity. Consistent with predictions from Drosophila, old queens had lower head expression of insulin-like peptide and its putative receptors than did old workers. Juvenile hormone affected the expression of Vg and insulin–IGF-1 signaling genes in opposite directions. These results suggest that conserved and species-specific mechanisms interact to regulate queen bee longevity without sacrificing fecundity. PMID:17438290

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

    PubMed

    Bellés, Xavier; Martín, David; Piulachs, Maria-Dolors

    2005-01-01

    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.

  7. A mutation in the receptor Methoprene-tolerant alters juvenile hormone response in insects and crustaceans.

    PubMed

    Miyakawa, Hitoshi; Toyota, Kenji; Hirakawa, Ikumi; Ogino, Yukiko; Miyagawa, Shinichi; Oda, Shigeto; Tatarazako, Norihisa; Miura, Toru; Colbourne, John K; Iguchi, Taisen

    2013-01-01

    Juvenile hormone is an essential regulator of major developmental and life history events in arthropods. Most of the insects use juvenile hormone III as the innate juvenile hormone ligand. By contrast, crustaceans use methyl farnesoate. Despite this difference that is tied to their deep evolutionary divergence, the process of this ligand transition is unknown. Here we show that a single amino-acid substitution in the receptor Methoprene-tolerant has an important role during evolution of the arthropod juvenile hormone pathway. Microcrustacea Daphnia pulex and D. magna share a juvenile hormone signal transduction pathway with insects, involving Methoprene-tolerant and steroid receptor coactivator proteins that form a heterodimer in response to various juvenoids. Juvenile hormone-binding pockets of the orthologous genes differ by only two amino acids, yet a single substitution within Daphnia Met enhances the receptor's responsiveness to juvenile hormone III. These results indicate that this mutation within an ancestral insect lineage contributed to the evolution of a juvenile hormone III receptor system.

  8. The role of allatostatins in juvenile hormone synthesis in insects and crustaceans.

    PubMed

    Stay, Barbara; Tobe, Stephen S

    2007-01-01

    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.

  9. Socially selected ornaments influence hormone titers of signalers and receivers.

    PubMed

    Tibbetts, Elizabeth A; Crocker, Katherine; Huang, Zachary Y

    2016-07-26

    Decades of behavioral endocrinology research have shown that hormones and behavior have a bidirectional relationship; hormones both influence and respond to social behavior. In contrast, hormones are often thought to have a unidirectional relationship with ornaments. Hormones influence ornament development, but little empirical work has tested how ornaments influence hormones throughout life. Here, we experimentally alter a visual signal of fighting ability in Polistes dominulus paper wasps and measure the behavioral and hormonal consequences of signal alteration in signalers and receivers. We find wasps that signal inaccurately high fighting ability receive more aggression than controls and receiving aggression reduces juvenile hormone (JH) titers. As a result, immediately after contests, inaccurate signalers have lower JH titers than controls. Ornaments also directly influence rival JH titers. Three hours after contests, wasps who interacted with rivals signaling high fighting ability have higher JH titers than wasps who interacted with rivals signaling low fighting ability. Therefore, ornaments influence hormone titers of both signalers and receivers. We demonstrate that relationships between hormones and ornaments are flexible and bidirectional rather than static and unidirectional. Dynamic relationships among ornaments, behavior, and physiology may be an important, but overlooked factor in the evolution of honest communication.

  10. Socially selected ornaments influence hormone titers of signalers and receivers

    PubMed Central

    Tibbetts, Elizabeth A.; Crocker, Katherine; Huang, Zachary Y.

    2016-01-01

    Decades of behavioral endocrinology research have shown that hormones and behavior have a bidirectional relationship; hormones both influence and respond to social behavior. In contrast, hormones are often thought to have a unidirectional relationship with ornaments. Hormones influence ornament development, but little empirical work has tested how ornaments influence hormones throughout life. Here, we experimentally alter a visual signal of fighting ability in Polistes dominulus paper wasps and measure the behavioral and hormonal consequences of signal alteration in signalers and receivers. We find wasps that signal inaccurately high fighting ability receive more aggression than controls and receiving aggression reduces juvenile hormone (JH) titers. As a result, immediately after contests, inaccurate signalers have lower JH titers than controls. Ornaments also directly influence rival JH titers. Three hours after contests, wasps who interacted with rivals signaling high fighting ability have higher JH titers than wasps who interacted with rivals signaling low fighting ability. Therefore, ornaments influence hormone titers of both signalers and receivers. We demonstrate that relationships between hormones and ornaments are flexible and bidirectional rather than static and unidirectional. Dynamic relationships among ornaments, behavior, and physiology may be an important, but overlooked factor in the evolution of honest communication. PMID:27402762

  11. How does juvenile hormone control insect metamorphosis and reproduction?

    PubMed

    Riddiford, Lynn M

    2012-12-01

    In insects juvenile hormone (JH) regulates both metamorphosis and reproduction. This lecture focuses on our current understanding of JH action at the molecular level in both of these processes based primarily on studies in the tobacco hornworm Manduca sexta, the flour beetle Tribolium castaneum, the mosquito Aedes aegypti, and the fruit fly Drosophila melanogaster. The roles of the JH receptor complex and the transcription factors that it regulates during larval molting and metamorphosis are summarized. Also highlighted are the intriguing interactions of the JH and insulin signaling pathways in both imaginal disc development and vitellogenesis. Critical actions of JH and its receptor in the timing of maturation of the adult optic lobe and of female receptivity in Drosophila are also discussed.

  12. Differential Juvenile Hormone Variations in Scale Insect Extreme Sexual Dimorphism.

    PubMed

    Vea, Isabelle Mifom; Tanaka, Sayumi; Shiotsuki, Takahiro; Jouraku, Akiya; Tanaka, Toshiharu; Minakuchi, Chieka

    2016-01-01

    Scale insects have evolved extreme sexual dimorphism, as demonstrated by sedentary juvenile-like females and ephemeral winged males. This dimorphism is established during the post-embryonic development; however, the underlying regulatory mechanisms have not yet been examined. We herein assessed the role of juvenile hormone (JH) on the diverging developmental pathways occurring in the male and female Japanese mealybug Planococcus kraunhiae (Kuwana). We provide, for the first time, detailed gene expression profiles related to JH signaling in scale insects. Prior to adult emergence, the transcript levels of JH acid O-methyltransferase, encoding a rate-limiting enzyme in JH biosynthesis, were higher in males than in females, suggesting that JH levels are higher in males. Furthermore, male quiescent pupal-like stages were associated with higher transcript levels of the JH receptor gene, Methoprene-tolerant and its co-activator taiman, as well as the JH early-response genes, Krüppel homolog 1 and broad. The exposure of male juveniles to an ectopic JH mimic prolonged the expression of Krüppel homolog 1 and broad, and delayed adult emergence by producing a supernumeral pupal stage. We propose that male wing development is first induced by up-regulated JH signaling compared to female expression pattern, but a decrease at the end of the prepupal stage is necessary for adult emergence, as evidenced by the JH mimic treatments. Furthermore, wing development seems linked to JH titers as JHM treatments on the pupal stage led to wing deformation. The female pedomorphic appearance was not reflected by the maintenance of high levels of JH. The results in this study suggest that differential variations in JH signaling may be responsible for sex-specific and radically different modes of metamorphosis.

  13. Differential Juvenile Hormone Variations in Scale Insect Extreme Sexual Dimorphism

    PubMed Central

    Vea, Isabelle Mifom; Tanaka, Sayumi; Shiotsuki, Takahiro; Jouraku, Akiya; Tanaka, Toshiharu; Minakuchi, Chieka

    2016-01-01

    Scale insects have evolved extreme sexual dimorphism, as demonstrated by sedentary juvenile-like females and ephemeral winged males. This dimorphism is established during the post-embryonic development; however, the underlying regulatory mechanisms have not yet been examined. We herein assessed the role of juvenile hormone (JH) on the diverging developmental pathways occurring in the male and female Japanese mealybug Planococcus kraunhiae (Kuwana). We provide, for the first time, detailed gene expression profiles related to JH signaling in scale insects. Prior to adult emergence, the transcript levels of JH acid O-methyltransferase, encoding a rate-limiting enzyme in JH biosynthesis, were higher in males than in females, suggesting that JH levels are higher in males. Furthermore, male quiescent pupal-like stages were associated with higher transcript levels of the JH receptor gene, Methoprene-tolerant and its co-activator taiman, as well as the JH early-response genes, Krüppel homolog 1 and broad. The exposure of male juveniles to an ectopic JH mimic prolonged the expression of Krüppel homolog 1 and broad, and delayed adult emergence by producing a supernumeral pupal stage. We propose that male wing development is first induced by up-regulated JH signaling compared to female expression pattern, but a decrease at the end of the prepupal stage is necessary for adult emergence, as evidenced by the JH mimic treatments. Furthermore, wing development seems linked to JH titers as JHM treatments on the pupal stage led to wing deformation. The female pedomorphic appearance was not reflected by the maintenance of high levels of JH. The results in this study suggest that differential variations in JH signaling may be responsible for sex-specific and radically different modes of metamorphosis. PMID:26894583

  14. Synthesis and binding affinity of an iodinated juvenile hormone

    SciTech Connect

    Prestwich, G.D.; Eng, W.S.; Robles, S.; Vogt, R.G.; Wisniewski, J.R.; Wawrzenczyk, C.

    1988-01-25

    The synthesis of the first iodinated juvenile hormone (JH) in enantiomerically enriched form is reported. This chiral compound, 12-iodo-JH I, has an iodine atom replacing a methyl group of the natural insect juvenile hormone, JH I, which is important in regulating morphogenesis and reproduction in the Lepidoptera. The unlabeled compound shows approximately 10% of the relative binding affinity for the larval hemolymph JH binding protein (JHBP) of Manduca sexta, which specifically binds natural /sup 3/H-10R,11S-JH I (labeled at 58 Ci/mmol) with a KD of 8 X 10(-8) M. It is also approximately one-tenth as biologically active as JH I in the black Manduca and epidermal commitment assays. The 12-hydroxy and 12-oxo compounds are poor competitors and are also biologically inactive. The radioiodinated (/sup 125/I)12-iodo-JH I can be prepared in low yield at greater than 2500 Ci/mmol by nucleophilic displacement using no-carrier-added /sup 125/I-labeled sodium iodide in acetone; however, synthesis using sodium iodide carrier to give the approximately 50 Ci/mmol radioiodinated ligand proceeds in higher radiochemical yield with fewer by-products and provides a radioligand which is more readily handled in binding assays. The KD of (/sup 125/I)12-iodo-JH I was determined for hemolymph JHBP of three insects: M. sexta, 795 nM; Galleria mellonella, 47 nM; Locusta migratoria, 77 nM. The selectivity of 12-iodo-JH I for the 32-kDa JHBP of M. sexta was demonstrated by direct autoradiography of a native polyacrylamide gel electrophoresis gel of larval hemolymph incubated with the radioiodinated ligand. Thus, the in vitro and in vivo activity of 12-iodo-JH I indicate that it can serve as an important new gamma-emitting probe in the search for JH receptor proteins in target tissues.

  15. Synthesis and binding affinity of an iodinated juvenile hormone.

    PubMed

    Prestwich, G D; Eng, W S; Robles, S; Vogt, R G; Wiśniewski, J R; Wawrzeńczyk, C

    1988-01-25

    The synthesis of the first iodinated juvenile hormone (JH) in enantiomerically enriched form is reported. This chiral compound, 12-iodo-JH I, has an iodine atom replacing a methyl group of the natural insect juvenile hormone, JH I, which is important in regulating morphogenesis and reproduction in the Lepidoptera. The unlabeled compound shows approximately 10% of the relative binding affinity for the larval hemolymph JH binding protein (JHBP) of Manduca sexta, which specifically binds natural 3H-10R,11S-JH I (labeled at 58 Ci/mmol) with a KD of 8 X 10(-8) M. It is also approximately one-tenth as biologically active as JH I in the black Manduca and epidermal commitment assays. The 12-hydroxy and 12-oxo compounds are poor competitors and are also biologically inactive. The radioiodinated [125I]12-iodo-JH I can be prepared in low yield at greater than 2500 Ci/mmol by nucleophilic displacement using no-carrier-added 125I-labeled sodium iodide in acetone; however, synthesis using sodium iodide carrier to give the approximately 50 Ci/mmol radioiodinated ligand proceeds in higher radiochemical yield with fewer by-products and provides a radioligand which is more readily handled in binding assays. The KD of [125I]12-iodo-JH I was determined for hemolymph JHBP of three insects: M. sexta, 795 nM; Galleria mellonella, 47 nM; Locusta migratoria, 77 nM. The selectivity of 12-iodo-JH I for the 32-kDa JHBP of M. sexta was demonstrated by direct autoradiography of a native polyacrylamide gel electrophoresis gel of larval hemolymph incubated with the radioiodinated ligand. Thus, the in vitro and in vivo activity of 12-iodo-JH I indicate that it can serve as an important new gamma-emitting probe in the search for JH receptor proteins in target tissues.

  16. The molecular site of action of juvenile hormone and juvenile hormone insecticides during metamorphosis: how these compounds kill insects.

    PubMed

    Wilson, Thomas G

    2004-01-01

    Studies in a variety of insects during the past four decades has deepened our understanding of juvenile hormone (JH) physiology, but how this hormone works at the molecular level remains elusive. Similarly, the mechanism of toxicity of JH analogue insecticides is still in question. There is much evidence from laboratory usage that JHAs act as JH agonists and generally show the highest toxicity when applied at the onset of metamorphosis. A physiological basis for the toxicity and morphogenetic effects has been suggested by recent work linking these effects with interference with the expression or action of certain genes, particularly the Broad-Complex (BR-C) transcription factor gene, that direct metamorphic change. Misexpressed BR-C then leads to improper expression of one or more downstream effector genes controlled by BR-C gene products, resulting in abnormal developmental and physiological changes that disrupt metamorphosis. Therefore, JH is a necessary molecule at certain times in insect development but becomes toxic when present during metamorphosis.

  17. TRANSGENERATIONAL EFFECTS OF A JUVENILE HORMONE MIMIC ON THE ESTUARINE MYSID, MYSIDOPSIS BAHIA (CRUSTACEA: MYSIDACEA)

    EPA Science Inventory

    Fenoxycarb is a juvenile hormone (JH) mimic used to control insect pests by interfering with reproductive and developmental processes mediated by JH. Crustaceans are ideal organisms to monitor environmental effects of these endocrine disruptors, since they are dominant aquatic ar...

  18. Sex-specific developmental profiles of juvenile hormone synthesis in honey bee larvae.

    PubMed

    Hartfelder, Klaus; de Oliveira Tozetto, Sibele; Rachinsky, Anna

    1993-02-01

    Juvenile hormone synthesis in drone larvae of the honey bee was measured by an in vitro radiochemical assay. The developmental profile of corpora allata activity in male larvae showed considerable differences from queen larvae, the presumptive reproductive females, and was comparable to workers, the sterile female morph. Drone and worker larvae, however, differed drastically in the regulation of juvenile hormone biosynthesis, as revealed by the addition of farnesoic acid to the culture medium. This precursor stimulated juvenile hormone synthesis of drone glands nearly eightfold, whereas in worker larvae it is known to lead to an accumulation of methyl farnesoate. The sex-specific differences in endocrine activity indicate a role for juvenile hormone in the expression of genetically determined sexually dimorphic characters during metamorphosis, a role not currently accounted for in models describing endocrine regulation of insect development.

  19. Biosynthesis of the Juvenile Hormones of Manduca sexta: Labeling Pattern from Mevalonate, Propionate, and Acetate

    PubMed Central

    Schooley, David A.; Judy, Kenneth J.; Bergot, B. John; Hall, M. Sharon; Siddall, John B.

    1973-01-01

    Using organ culture, high-resolution liquid chromatography, and microchemical techniques, we demonstrated the efficient incorporation in vitro of several radiolabeled precursors into the two juvenile hormones of Manduca sexta. JH II, a homosesquiterpene hormone, reported from M. sexta as well as several other insects, incorporates radiolabel from acetate, mevalonate, and propionate. JH III, a sesquiterpene hormone recently reported as a natural product of M. sexta, incorporates label from acetate and mevalonate, but not from propionate. Based on the position of the labeled atoms in the precursors and upon the position of incorporation obtained from label-distribution data, a scheme for juvenile hormone biosynthesis is advanced. PMID:16592112

  20. Juvenile hormone and allatostatins in the German cockroach embryo.

    PubMed

    Maestro, José L; Pascual, Núria; Treiblmayr, Karl; Lozano, Jesús; Bellés, Xavier

    2010-09-01

    Levels of juvenile hormone III (JH), FGLamide allatostatin peptides (ASTs), ASTs precursor (preproAST) mRNA and methyl farnesoate epoxidase (CYP15A1) mRNA were measured in embryos of the cockroach Blattella germanica. JH starts to rise just after dorsal closure, reaches maximal levels between 60% and 80% of embryogenesis, and decrease subsequently to undetectable levels. ASTs show low levels during the first two thirds of embryogenesis, increase thereafter and maintain high levels until hatching. PreproAST mRNA shows quite high levels during the two days following oviposition, thus behaving as a maternal transcript, the levels then become very low until mid embryogenesis, and increase afterwards, peaking towards the end of embryo development. CYP15A1 transcripts were detected around 25% embryogenesis and the levels tended to increase through embryogenesis, although differences amongst the days studied were not statistically significant. The opposite patterns of JH and AST towards the end of embryo development, along with the detection of AST immunoreactivity in corpora allata from late embryos, suggest that JH decline is caused by the increase of AST. Moreover, the uncorrelated patterns of JH concentration and CYP15A1 mRNA levels suggest that CYP15A1 expression does not modulate JH production.

  1. Molecular impact of juvenile hormone agonists on neonatal Daphnia magna.

    PubMed

    Toyota, Kenji; Kato, Yasuhiko; Miyakawa, Hitoshi; Yatsu, Ryohei; Mizutani, Takeshi; Ogino, Yukiko; Miyagawa, Shinichi; Watanabe, Hajime; Nishide, Hiroyo; Uchiyama, Ikuo; Tatarazako, Norihisa; Iguchi, Taisen

    2014-05-01

    Daphnia magna has been used extensively to evaluate organism- and population-level responses to pollutants in acute toxicity and reproductive toxicity tests. We have previously reported that exposure to juvenile hormone (JH) agonists results in a reduction of reproductive function and production of male offspring in a cyclic parthenogenesis, D. magna. Recent advances in molecular techniques have provided tools to understand better the responses to pollutants in aquatic organisms, including D. magna. DNA microarray was used to evaluate gene expression profiles of neonatal daphnids exposed to JH agonists: methoprene (125, 250 and 500 ppb), fenoxycarb (0.5, 1 and 2 ppb) and epofenonane (50, 100 and 200 ppb). Exposure to these JH analogs resulted in chemical-specific patterns of gene expression. The heat map analyses based on hierarchical clustering revealed a similar pattern between treatments with a high dose of methoprene and with epofenonane. In contrast, treatment with low to middle doses of methoprene resulted in similar profiles to fenoxycarb treatments. Hemoglobin and JH epoxide hydrolase genes were clustered as JH-responsive genes. These data suggest that fenoxycarb has high activity as a JH agonist, methoprene shows high toxicity and epofenonane works through a different mechanism compared with other JH analogs, agreeing with data of previously reported toxicity tests. In conclusion, D. magna DNA microarray is useful for the classification of JH analogs and identification of JH-responsive genes.

  2. Ecdysis triggering hormone ensures proper timing of juvenile hormone biosynthesis in pharate adult mosquitoes.

    PubMed

    Areiza, Maria; Nouzova, Marcela; Rivera-Perez, Crisalejandra; Noriega, Fernando G

    2014-11-01

    Juvenile hormones (JHs) are synthesized by the corpora allata (CA) and play a key role in insect development. A decrease of JH titer in the last instar larvae allows pupation and metamorphosis to proceed. As the anti-metamorphic role of JH comes to an end, the CA of the late pupa (or pharate adult) becomes again "competent" to synthesize JH, which would play an essential role orchestrating reproductive maturation. In the present study, we provide evidence that ecdysis triggering hormone (ETH), a key endocrine factor involved in ecdysis control, acts as an allatotropic regulator of JH biosynthesis, controlling the exact timing of CA activation in the pharate adult mosquito. Analysis of the expression of Aedes aegypti ETH receptors (AeaETHRs) revealed that they are present in the CA and the corpora cardiaca (CC), and their expression peaks 4 h before eclosion. In vitro stimulation of the pupal CA glands with ETH resulted in an increase in JH synthesis. Consistent with this finding, silencing AeaETHRs by RNA interference (RNAi) in pupa resulted in reduced JH synthesis by the CA of one day-old adult females. Stimulation with ETH resulted in increases in the activity of juvenile hormone acid methyltransferase (JHAMT), a key JH biosynthetic enzyme. Furthermore, inhibition of IP3R-operated mobilization of endoplasmic reticulum Ca(2+) stores prevented the ETH-dependent increases of JH biosynthesis and JHAMT activity. All together these findings provide compelling evidence that ETH acts as a regulatory peptide that ensures proper developmental timing of JH synthesis in pharate adult mosquitoes.

  3. Ecdysis triggering hormone ensures proper timing of juvenile hormone biosynthesis in pharate adult mosquitoes

    PubMed Central

    Areiza, Maria; Nouzova, Marcela; Rivera-Perez, Crisalejandra; Noriega, Fernando G.

    2014-01-01

    Juvenile hormones (JHs) are synthesized by the corpora allata (CA) and play a key role in insect development. A decrease of JH titer in the last instar larvae allows pupation and metamorphosis to proceed. As the anti-metamorphic role of JH comes to an end, the CA of the late pupa (or pharate adult) becomes again “competent” to synthesize JH, which would play an essential role orchestrating reproductive maturation. In the present study, we provide evidence that ecdysis triggering hormone (ETH), a key endocrine factor involved in ecdysis control, acts as an allatotropic regulator of JH biosynthesis, controlling the exact timing of CA activation in the pharate adult mosquito. Analysis of the expression of Aedes aegypti ETH receptors (AeaETHRs) revealed that they are present in the CA and the corpora cardiaca (CC), and their expression peaks 4 h before eclosion. In vitro stimulation of the pupal CA glands with ETH resulted in an increase in JH synthesis. Consistent with this finding, silencing AeaETHRs by RNA interference (RNAi) in pupa resulted in reduced JH synthesis by the CA of one day-old adult females. Stimulation with ETH resulted in increases in the activity of juvenile hormone acid methyltransferase (JHAMT), a key JH biosynthetic enzyme. Furthermore, inhibition of IP3R-operated mobilization of endoplasmic reticulum Ca2+ stores prevented the ETH-dependent increases of JH biosynthesis and JHAMT activity. All together these findings provide compelling evidence that ETH acts as a regulatory peptide that ensures proper developmental timing of JH synthesis in pharate adult mosquitoes. PMID:25257939

  4. Exploring the role of juvenile hormone and vitellogenin in reproduction and social behavior in bumble bees

    PubMed Central

    2014-01-01

    Background The genetic and physiological pathways regulating behavior in solitary species are hypothesized to have been co-opted to regulate social behavior in social species. One classic example is the interaction between vitellogenin (an egg-yolk and storage protein) and juvenile hormone, which are positively correlated in most insect species but have modified interactions in highly eusocial insects. In some of these species (including some termites, ants, and the honey bee), juvenile hormone and vitellogenin levels are negatively correlated and juvenile hormone has shifted its role from a gonadotropin to a regulator of maturation and division of labor in the primarily sterile workers. The function of vitellogenin also seems to have broadened to encompass similar roles. Thus, the functions and molecular interactions of juvenile hormone and vitellogenin are hypothesized to have undergone changes during the evolution of eusociality, but the mechanisms underlying these changes are unknown. Bumble bees offer an excellent model system for testing how the relationship between juvenile hormone and vitellogenin evolved from solitary to social species. Bumble bee colonies are primitively eusocial and comprised of a single reproductive queen and facultatively sterile workers. In Bombus terrestris, juvenile hormone retains its ancestral role as a gonadotropin and is also hypothesized to regulate aggressive behavior. However, the function of vitellogenin and its interactions with juvenile hormone have not yet been characterized. Results By characterizing vitellogenin RNA expression levels (vg) in B. terrestris we show that vg is not associated with task and only partially associated with worker age, queen presence, and caste (queen vs worker). The correlations of vg with ovarian activation were not consistent across experiments, but both vg and ovarian activation were significantly associated with levels of aggression experienced by workers. Treatment with juvenile hormone

  5. Exploring the role of juvenile hormone and vitellogenin in reproduction and social behavior in bumble bees.

    PubMed

    Amsalem, Etya; Malka, Osnat; Grozinger, Christina; Hefetz, Abraham

    2014-03-11

    The genetic and physiological pathways regulating behavior in solitary species are hypothesized to have been co-opted to regulate social behavior in social species. One classic example is the interaction between vitellogenin (an egg-yolk and storage protein) and juvenile hormone, which are positively correlated in most insect species but have modified interactions in highly eusocial insects. In some of these species (including some termites, ants, and the honey bee), juvenile hormone and vitellogenin levels are negatively correlated and juvenile hormone has shifted its role from a gonadotropin to a regulator of maturation and division of labor in the primarily sterile workers. The function of vitellogenin also seems to have broadened to encompass similar roles. Thus, the functions and molecular interactions of juvenile hormone and vitellogenin are hypothesized to have undergone changes during the evolution of eusociality, but the mechanisms underlying these changes are unknown.Bumble bees offer an excellent model system for testing how the relationship between juvenile hormone and vitellogenin evolved from solitary to social species. Bumble bee colonies are primitively eusocial and comprised of a single reproductive queen and facultatively sterile workers. In Bombus terrestris, juvenile hormone retains its ancestral role as a gonadotropin and is also hypothesized to regulate aggressive behavior. However, the function of vitellogenin and its interactions with juvenile hormone have not yet been characterized. By characterizing vitellogenin RNA expression levels (vg) in B. terrestris we show that vg is not associated with task and only partially associated with worker age, queen presence, and caste (queen vs worker). The correlations of vg with ovarian activation were not consistent across experiments, but both vg and ovarian activation were significantly associated with levels of aggression experienced by workers. Treatment with juvenile hormone did not affect vg

  6. Microarray Analysis of Juvenile Hormone Response in Drosophila melanogaster S2 cells

    USDA-ARS?s Scientific Manuscript database

    A microchip array encompassing probes for 14,010 genes of Drosophila melanogaster was used to analyze the effect of juvenile hormone (JH) on genome-wide gene expression. JH is a member of a key group of insect hormones involved in regulating larval development and adult reproductive processes. Altho...

  7. Evolutionary Endocrinology of Hormonal Rhythms: Juvenile Hormone Titer Circadian Polymorphism in Gryllus firmus.

    PubMed

    Zera, Anthony J

    2016-08-01

    Daily rhythms for hormonal traits are likely widespread and important aspects of organismal (e.g., life history) adaptation. Yet they remain substantially understudied, especially with respect to variable rhythms within species. The cricket, Gryllus firmus, exhibits a genetically polymorphic circadian rhythm for the blood titer of the key hormone, juvenile hormone (JH). Gryllus firmus is also wing-polymorphic, consisting of a dispersing morph that delays reproduction and a flightless morph with substantially enhanced egg production. JH circadian phenotype strongly covaries with morph type: The blood JH titer is strongly rhythmic in multiple populations artificially-selected for the dispersing morph (LW(f) = long wings with functional flight muscles) and is essentially arrhythmic in populations selected for the SW (short-winged) morph. Association between JH titer cycle and LW(f) morph is also found in natural populations of G. firmus and in several related species in the field. This is one of the very few studies of endocrine titer variation in natural populations of an insect. The morph-specific cycle is underlain by a circadian rhythm in hormone biosynthesis, which in turn is underlain by a rhythm in a brain neuropeptide regulator of JH biosynthesis. The morph-specific JH titer circadian cycle is also strongly correlated with a morph-specific daily rhythm in global gene expression. This is currently the only example of a genetically-variable hormone circadian rhythm in both the laboratory and field that is strongly associated with an ecologically important polymorphism. The extensive information on the underlying causes of the morph-specific JH titer rhythm, coupled with the strong association between the JH circadian rhythm and wing polymorphism makes this system in G. firmus an exceptional experimental model to investigate the mechanisms underlying circadian hormonal adaptations. Genetic polymorphism for the JH titer circadian rhythm in G. firmus is discussed

  8. Spruce budworm (Choristoneura fumiferana) juvenile hormone esterase: hormonal regulation, developmental expression and cDNA cloning.

    PubMed

    Feng, Q L; Ladd, T R; Tomkins, B L; Sundaram, M; Sohi, S S; Retnakaran, A; Davey, K G; Palli, S R

    1999-02-25

    We have used the differential display of mRNAs technique to identify Choristoneura fumiferana genes that are induced by juvenile hormone I (JH I). Of the six PCR products identified, one bound to a 2.8-kb mRNA from CF-203 cells whose abundance increased when the cells were grown in the presence of JH I. The same 2.8-kb mRNA decreased to undetectable levels when the CF-203 cells were grown in the presence of 20-hydroxyecdysone (20E). The PCR fragment probe also detected a 2.8-kb mRNA in the C. fumiferana larval tissues. This 2.8-kb mRNA was present on the first day of the first, third, fourth, fifth and sixth larval and pupal stadia, but was conspicuously absent on the first day of the second larval stadium, as well as during the intermolt periods of the first to fifth instar larval stages. In the sixth instar larvae the 2.8-kb mRNA was detected in the fat body, epidermis and midgut during the intermolt period. The PCR fragment was used as a probe to screen a cDNA library. The deduced amino acid sequence of this 2.8-kb cDNA clone showed similarity with the deduced amino acid sequences of Heliothis virescens juvenile hormone esterases (HvJHE). The deduced amino acid sequence of the cDNA clone contained all five functional motifs that are present in most of esterases, proteases and lipases. The cDNA clone was expressed in the baculovirus expression system, producing a protein that showed JHE activity.

  9. Juvenile hormone regulates extreme mandible growth in male stag beetles.

    PubMed

    Gotoh, Hiroki; Cornette, Richard; Koshikawa, Shigeyuki; Okada, Yasukazu; Lavine, Laura Corley; Emlen, Douglas J; Miura, Toru

    2011-01-01

    The morphological diversity of insects is one of the most striking phenomena in biology. Evolutionary modifications to the relative sizes of body parts, including the evolution of traits with exaggerated proportions, are responsible for a vast range of body forms. Remarkable examples of an insect trait with exaggerated proportions are the mandibular weapons of stag beetles. Male stag beetles possess extremely enlarged mandibles which they use in combat with rival males over females. As with other sexually selected traits, stag beetle mandibles vary widely in size among males, and this variable growth results from differential larval nutrition. However, the mechanisms responsible for coupling nutrition with growth of stag beetle mandibles (or indeed any insect structure) remain largely unknown. Here, we demonstrate that during the development of male stag beetles (Cyclommatus metallifer), juvenile hormone (JH) titers are correlated with the extreme growth of an exaggerated weapon of sexual selection. We then investigate the putative role of JH in the development of the nutritionally-dependent, phenotypically plastic mandibles, by increasing hemolymph titers of JH with application of the JH analog fenoxycarb during larval and prepupal developmental periods. Increased JH signaling during the early prepupal period increased the proportional size of body parts, and this was especially pronounced in male mandibles, enhancing the exaggerated size of this trait. The direction of this response is consistent with the measured JH titers during this same period. Combined, our results support a role for JH in the nutrition-dependent regulation of extreme mandible growth in this species. In addition, they illuminate mechanisms underlying the evolution of trait proportion, the most salient feature of the evolutionary diversification of the insects.

  10. Production of male neonates in Daphnia magna (Cladocera, Crustacea) exposed to juvenile hormones and their analogs.

    PubMed

    Oda, Shigeto; Tatarazako, Norihisa; Watanabe, Hajime; Morita, Masatoshi; Iguchi, Taisen

    2005-12-01

    We exposed the water flea Daphnia magna (Cladocera, Crustacea) to either juvenile hormone I (JH I), juvenile hormone II (JH II), or the juvenile hormone-mimicking insecticides kinoprene, hydroprene, epofenonane, or fenoxycarb. By 21-day reproduction tests, we investigated the effects on the number of neonates born per female and the offspring sex ratio. All six chemicals induced D. magna to produce male neonates; the male sex ratio of the offspring increased as the chemical concentration increased. EC50 values for production of male neonates were estimated as 400 (JH I), 410 (JH II), 190 (kinoprene), 2.9 (hydroprene), 64 (epofenonane), and 0.92 (fenoxycarb) microg/l. The number of neonates produced was reduced with all chemicals at the concentrations investigated. At the EC50 for male production, five of the six chemicals reduced the reproductive rate to less than 50%; the exception was epofenonane, which caused only a slight reduction in reproductive rate. These results were similar to those obtained for five juvenoids studied previously, one of which was studied here again. There are now 10 chemical substances--all juvenile hormones or their analogs-that are known to induce D. magna to produce male neonates. This suggests that juvenile hormone is involved in initiating male production followed by sexual reproduction in D. magna, and probably in most cladocerans that exhibit cyclic parthenogenesis.

  11. Juvenile hormone regulation of male accessory gland activity in the red flour beetle, Tribolium castaneum

    PubMed Central

    Parthasarathy, R.; Tan, A.; Sun, Z.; Chen, J.; Rainkin, M.; Palli, S. R.

    2009-01-01

    Male accessory gland proteins (Acps) act as key modulators of reproductive success in insects by influencing the female reproductive physiology and behavior. We used custom microarrays and identified 112 genes that were highly expressed in male accessory glands (MAG) in the red flour beetle, Tribolium castaneum. Out of these 112 identified genes, 59 of them contained sequences coding for signal peptide and cleavage site and the remaining 53 contained transmembrane domains. The expression of 14 these genes in the MAG but not in other tissues of male or female was confirmed by quantitative real-time PCR. In virgin males, juvenile hormone (JH) levels increased from second day post adult emergence (PAE), remained high on third day PAE and declined on fourth day PAE. The ecdysteroid titers were high soon after adult emergence but declined to minimal levels from 1-5 days PAE. Feeding of juvenile hormone analog, hydroprene, but not the ecdysteroid analog, RH-2485, showed an increase in size of MAGs, as well as an increase in total RNA and protein content of MAG. Hydroprene treatment also increased the expression Acp genes in the MAG. RNAi-mediated knock-down in the expression of JHAMT gene decreased the size of MAGs and expression of Acps. JH deficiency influenced male reproductive fitness as evidenced by a less vigor in mating behavior, poor sperm transfer, low egg and the progeny production by females mated with the JH deficient males. These data suggest a critical role for JH in the regulation of male reproduction especially through MAG secretions. PMID:19324087

  12. Juvenile hormone regulation of male accessory gland activity in the red flour beetle, Tribolium castaneum.

    PubMed

    Parthasarathy, R; Tan, A; Sun, Z; Chen, Z; Rankin, M; Palli, S R

    2009-07-01

    Male accessory gland proteins (Acps) act as key modulators of reproductive success in insects by influencing the female reproductive physiology and behavior. We used custom microarrays and identified 112 genes that were highly expressed in male accessory glands (MAG) in the red flour beetle, Tribolium castaneum. Out of these 112 identified genes, 59 of them contained sequences coding for signal peptide and cleavage site and the remaining 53 contained transmembrane domains. The expression of 14 of these genes in the MAG but not in other tissues of male or female was confirmed by quantitative real-time PCR. In virgin males, juvenile hormone (JH) levels increased from second day post adult emergence (PAE), remained high on third day PAE and declined on fourth day PAE. The ecdysteroid titers were high soon after adult emergence but declined to minimal levels from 1 to 5 days PAE. Feeding of juvenile hormone analog, hydroprene, but not the ecdysteroid analog, RH-2485, showed an increase in size of MAGs, as well as an increase in total RNA and protein content of MAG. Hydroprene treatment also increased the expression of Acp genes in the MAG. RNAi-mediated knock-down in the expression of JHAMT gene decreased the size of MAGs and expression of Acps. JH deficiency influenced male reproductive fitness as evidenced by a less vigor in mating behavior, poor sperm transfer, low egg and the progeny production by females mated with the JH deficient males. These data suggest a critical role for JH in the regulation of male reproduction especially through MAG secretions.

  13. ISOLATION OF JUVENILE HORMONES ESTERASE AND ITS PARTIAL CDNA CLONE FROM THE BEETLE, TENEBRIO MOLITOR. (R825433)

    EPA Science Inventory

    Juvenile hormone esterase (JHE) plays an essential role in insect development. It is partially responsible for the clearance of juvenile hormone (JH) which regulates various aspects of insect development and reproduction. Because of its role in regulating JH titer, this enzyme...

  14. ISOLATION OF JUVENILE HORMONES ESTERASE AND ITS PARTIAL CDNA CLONE FROM THE BEETLE, TENEBRIO MOLITOR. (R825433)

    EPA Science Inventory

    Juvenile hormone esterase (JHE) plays an essential role in insect development. It is partially responsible for the clearance of juvenile hormone (JH) which regulates various aspects of insect development and reproduction. Because of its role in regulating JH titer, this enzyme...

  15. High specific activity enantiomerically enriched juvenile hormones: synthesis and binding assay

    SciTech Connect

    Prestwich, G.D.; Wawrzenczyk, C.

    1985-08-01

    A stereoselective total synthesis of chiral juvenile hormone I is described that allows stoichiometric introduction of two tritium atoms in the final step. Both optical antipodes of the pivotal epoxy alcohol intermediate were prepared in 95% enantiomeric excess by the Sharpless epoxidation of a (Z)-allylic alcohol. Elaboration of the hydroxy-methyl group to a vinyl group followed by selective homogeneous tritiation affords optically active juvenile hormone I analogs at 58 Ci/mmol. Competitive binding of the labeled 10R, 11S and 10S,11R enantiomers with unlabeled enantiomers to the hemolymph binding protein of Manduca sexta larvae was determined by using a dextran-coated charcoal assay. The natural 10R,11S enantiomer has twice the relative binding affinity of the 10S,11R enantiomer. The availability of such high specific activity optically pure hormones will contribute substantially to the search for high-affinity receptors for juvenile hormones in the nuclei of cells. Moreover, the chiral 12-hydroxy-(10R,11S)-epoxy intermediate allows modification of juvenile hormone for solid-phase biochemical and radioimmunochemical work without altering either the biologically important carbomethoxy or epoxy recognition sites.

  16. High specific activity enantiomerically enriched juvenile hormones: synthesis and binding assay.

    PubMed Central

    Prestwich, G D; Wawrzeńczyk, C

    1985-01-01

    A stereoselective total synthesis of chiral juvenile hormone I is described that allows stoichiometric introduction of two tritium atoms in the final step. Both optical antipodes of the pivotal epoxy alcohol intermediate were prepared in 95% enantiomeric excess by the Sharpless epoxidation of a (Z)-allylic alcohol. Elaboration of the hydroxy-methyl group to a vinyl group followed by selective homogeneous tritiation affords optically active juvenile hormone I analogs at 58 Ci/mmol. Competitive binding of the labeled 10R, 11S and 10S,11R enantiomers with unlabeled enantiomers to the hemolymph binding protein of Manduca sexta larvae was determined by using a dextran-coated charcoal assay. The natural 10R,11S enantiomer has twice the relative binding affinity of the 10S,11R enantiomer. The availability of such high specific activity optically pure hormones will contribute substantially to the search for high-affinity receptors for juvenile hormones in the nuclei of cells. Moreover, the chiral 12-hydroxy-(10R,11S)-epoxy intermediate allows modification of juvenile hormone for solid-phase biochemical and radioimmunochemical work without altering either the biologically important carbomethoxy or epoxy recognition sites. PMID:3860862

  17. High specific activity enantiomerically enriched juvenile hormones: synthesis and binding assay.

    PubMed

    Prestwich, G D; Wawrzeńczyk, C

    1985-08-01

    A stereoselective total synthesis of chiral juvenile hormone I is described that allows stoichiometric introduction of two tritium atoms in the final step. Both optical antipodes of the pivotal epoxy alcohol intermediate were prepared in 95% enantiomeric excess by the Sharpless epoxidation of a (Z)-allylic alcohol. Elaboration of the hydroxy-methyl group to a vinyl group followed by selective homogeneous tritiation affords optically active juvenile hormone I analogs at 58 Ci/mmol. Competitive binding of the labeled 10R, 11S and 10S,11R enantiomers with unlabeled enantiomers to the hemolymph binding protein of Manduca sexta larvae was determined by using a dextran-coated charcoal assay. The natural 10R,11S enantiomer has twice the relative binding affinity of the 10S,11R enantiomer. The availability of such high specific activity optically pure hormones will contribute substantially to the search for high-affinity receptors for juvenile hormones in the nuclei of cells. Moreover, the chiral 12-hydroxy-(10R,11S)-epoxy intermediate allows modification of juvenile hormone for solid-phase biochemical and radioimmunochemical work without altering either the biologically important carbomethoxy or epoxy recognition sites.

  18. A mosquito hemolymph odorant-binding protein family member specifically binds juvenile hormone.

    PubMed

    Kim, Il Hwan; Pham, Van; Jablonka, Willy; Goodman, Walter G; Ribeiro, José M C; Andersen, John F

    2017-09-15

    Juvenile hormone (JH) is a key regulator of insect development and reproduction. In adult mosquitoes, it is essential for maturation of the ovary and normal male reproductive behavior, but how JH distribution and activity is regulated after secretion is unclear. Here, we report a new type of specific JH-binding protein, given the name mosquito juvenile hormone-binding protein (mJHBP), which circulates in the hemolymph of pupal and adult Aedes aegypti males and females. mJHBP is a member of the odorant-binding protein (OBP) family, and orthologs are present in the genomes of Aedes, Culex, and Anopheles mosquito species. Using isothermal titration calorimetry, we show that mJHBP specifically binds JH II and JH III but not eicosanoids or JH derivatives. mJHBP was crystallized in the presence of JH III and found to have a double OBP domain structure reminiscent of salivary "long" D7 proteins of mosquitoes. We observed that a single JH III molecule is contained in the N-terminal domain binding pocket that is closed in an apparent conformational change by a C-terminal domain-derived α-helix. The electron density for the ligand indicated a high occupancy of the natural 10R enantiomer of JH III. Of note, mJHBP is structurally unrelated to hemolymph JHBP from lepidopteran insects. A low level of expression of mJHBP in Ae. aegypti larvae suggests that it is primarily active during the adult stage where it could potentially influence the effects of JH on egg development, mating behavior, feeding, or other processes.

  19. Do hormones influence melanoma? Facts and controversies.

    PubMed

    Gupta, Amie; Driscoll, Marcia S

    2010-01-01

    The issue of whether hormones influence malignant melanoma (MM) has been controversial for many years. Although early case reports demonstrated a negative effect of hormones, recent evidence has not supported a potential role for hormones in MM. We address whether exogenous and endogenous hormones influence a woman's risk for MM or affect her prognosis if diagnosed with MM. Multiple epidemiologic studies show the use of oral contraceptives or hormone replacement therapy does not appear to increase a woman's risk for MM. Pregnancy does not appear to influence a woman's risk of MM, nor does pregnancy appear to affect prognosis in the woman diagnosed with MM. When counseling the woman who is diagnosed with MM during pregnancy or during the childbearing years, future use of oral contraceptives or hormone replacement therapy is not contraindicated; counseling concerning future pregnancies should be done on a case-by-case basis, with emphasis placed on established prognostic factors for MM.

  20. A Structural Equation Modeling Analysis of Influences on Juvenile Delinquency

    ERIC Educational Resources Information Center

    Barrett, David E.; Katsiyannis, Antonis; Zhang, Dalun; Zhang, Dake

    2014-01-01

    This study examined influences on delinquency and recidivism using structural equation modeling. The sample comprised 199,204 individuals: 99,602 youth whose cases had been processed by the South Carolina Department of Juvenile Justice and a matched control group of 99,602 youth without juvenile records. Structural equation modeling for the…

  1. A Structural Equation Modeling Analysis of Influences on Juvenile Delinquency

    ERIC Educational Resources Information Center

    Barrett, David E.; Katsiyannis, Antonis; Zhang, Dalun; Zhang, Dake

    2014-01-01

    This study examined influences on delinquency and recidivism using structural equation modeling. The sample comprised 199,204 individuals: 99,602 youth whose cases had been processed by the South Carolina Department of Juvenile Justice and a matched control group of 99,602 youth without juvenile records. Structural equation modeling for the…

  2. Evolutionary Endocrinology of Juvenile Hormone Esterase in Gryllus Assimilis: Direct and Correlated Responses to Selection

    PubMed Central

    Zera, A. J.; Zhang, C.

    1995-01-01

    Hemolymph juvenile hormone esterase (JHE) activity on the third day of the last stadium in the cricket, Gryllus assimilis, exhibited a significant response to selection in each of six replicate lines. Mean realized heritability was 0.26 +/- 0.04. The response was due to changes in whole-organism enzyme activity as well as to changes in the proportion of enzyme allocated to the hemolymph compartment. In vivo juvenile hormone metabolism differed between some lines selected for high vs. low enzyme activity. Only minimal differences were observed between lines with respect to hemolymph protein concentration or whole-cricket activity of juvenile hormone epoxide hydrolase, the other major JH-degrading enzyme. Dramatic correlated responses to selection, equal in magnitude to the direct response, were observed for JHE activity on each of three other days of the last juvenile stadium. In contrast, no correlated responses in JHE activity were observed in adults. This indicates that JHE activities throughout the last stadium will evolve as a highly correlated unit independent of adult activities and the evolution of endocrine mechanisms regulating juvenile development can be decoupled from those controlling adult reproduction. This study represents the first quantitative-genetic analysis of naturally occurring endocrine variation in an insect species. PMID:8582618

  3. Juvenile Hormone Regulation of Drosophila Epac - A Guanine Nucleotide Exchange Factor for Rap1 Small GTPase

    USDA-ARS?s Scientific Manuscript database

    Previously, we utilized a microchip array encompassing probes for 14,010 genes of Drosophila melanogaster to analyze the effect of (10R) juvenile hormone III (JH) on genome-wide gene expression in Drosophila S2 cells. Treatment with JH yielded a collection of 32 gene transcripts that demonstrated a ...

  4. Production of male neonates in four cladoceran species exposed to a juvenile hormone analog, fenoxycarb.

    PubMed

    Oda, Shigeto; Tatarazako, Norihisa; Watanabe, Hajime; Morita, Masatoshi; Iguchi, Taisen

    2005-06-01

    Previous studies have found that exposure of a cyclic parthenogen, the water flea Daphnia magna (Cladocera, Crustacea), to juvenile hormones and their analogs results in the production of neonates of male sex at concentration-dependent rates. We conducted reproduction experiments in four different species (Moina macrocopa, M. micrura, Ceriodaphnia dubia and C. reticulata) of cladoceran to test for the first time whether the occurrence of this phenomenon after exposure of the parent to such hormones is a generalized phenomenon. In the presence of a juvenile hormone analog, fenoxycarb, all four species produced male neonates and showed reduced rates of reproduction. The estimated median effective concentration (EC50) for the production of male neonates varied with species, ranging from 0.60 x 10(3) to 9.3 x 10(3) ng/l. Although there was a wide range of sensitivity to fenoxycarb, the production of male neonates in all four species demonstrates that this phenomenon is a common response to juvenile hormone analogs and further suggests that these hormones are capable of initiating sexual reproduction in cladocerans, most of which exhibit cyclic parthenogenesis.

  5. Influence of Photoperiod and Temperature on Migrations of Meloidogyne Juveniles

    PubMed Central

    Prot, Jean-Claude; Van Gundy, S. D.

    1981-01-01

    Photoperiod influences the migration of M. incognita juveniles toward tomato roots. Approximately 33% migrated vertically 20 cm in 7 days to roots when 12 h dark were alternated with 12 h light. Only 7% migrated when light was constant for 24 h. Vertical migration of M. incognita juveniles was studied at 14, 16, 18, 20, and 22 C. The migration of M. incognita juveniles begins at about 18 C and reaches its maximum at 22 C. The migration of M. hapla and M. incognita juveniles were compared at 14, 18, and 22 C. Juveniles of M. hapla were able to migrate at a lower temperature than those of M. incognita. With M. hapla, there was no significant difference in migration between 18 and 22 C. PMID:19300748

  6. Emergence, survival, and fecundity of adult cat fleas (Siphonaptera: Pulicidae) exposed as pupae to juvenile hormone mimics.

    PubMed

    Miller, R J; Broce, A B; Dryden, M W; Throne, J E

    1999-11-01

    Cat flea, Ctenocephalides felis felis (Bouché), adults exposed to sprays of methoprene, pyriproxyfen, or fenoxycarb as cocooned pupae emerged approximately 1 d earlier than adults from water-treated control pupae. Mortality of adult fleas, after exposure to juvenile hormone mimics as pupae, was increased over that of controls. Females had higher mortality than males within the first 48 h of feeding. Fecundity of females exposed as pupae to juvenile hormone mimics was not different from that of controls. Early emergence of preemerged adults from treated cocoons is discussed along with reasons for higher female susceptibility to juvenile hormone mimics.

  7. Juvenile Hormone Synthesis: “esterify then epoxidize” or “epoxidize then esterify”? Insights from the Structural Characterization of Juvenile Hormone Acid Methyltransferase

    PubMed Central

    Defelipe, L.A; Dolghih, E.; Roitberg, A.E.; Nouzova, M.; Mayoral, J.G; Noriega, F.G.; Turjanski, A.G.

    2011-01-01

    Juvenile hormones (JHs) play key roles in regulating metamorphosis and reproduction in insects. The last two steps of JH synthesis diverge depending on the insect order. In Lepidoptera, epoxidation by a P450 monooxygenase precedes esterification by a juvenile hormone acid methyltransferase (JHAMT). In Orthoptera, Dictyoptera, Coleoptera and Diptera epoxidation follows methylation. The aim of our study was to gain insight into the structural basis of JHAMT’s substrate recognition as a means to understand the divergence of these pathways. Homology modeling was used to build the structure of Aedes aegypti JHAMT. The substrate binding site was identified, as well as the residues that interact with the methyl donor (S-adenosylmethionine) and the carboxylic acid of the substrate methyl acceptors, farnesoic acid (FA) and juvenile hormone acid (JHA). To gain further insight we generated the structures of Anopheles gambiae, Bombyx mori, Drosophila melanogaster and Tribolium castaneum JHAMTs. The modeling results were compared with previous experimental studies using recombinant proteins, whole insects, corpora allata or tissue extracts. The computational study helps explain the selectivity towards the (10R)-JHA isomer and the reduced activity for palmitic and lauric acids. The analysis of our results supports the hypothesis that all insect JHAMTs are able to recognize both FA and JHA as substrates. Therefore, the order of the methylation/epoxidation reactions may be primarily imposed by the epoxidase’s substrate specificity. In Lepidoptera, epoxidase might have higher affinity than JHAMT for FA, so epoxidation precedes methylation, while in most other insects there is no epoxidation of FA, but esterification of FA to form MF, followed by epoxidation to JH III. PMID:21195763

  8. Wolbachia-induced paternal defect in Drosophila is likely by interaction with the juvenile hormone pathway.

    PubMed

    Liu, Chen; Wang, Jia-Lin; Zheng, Ya; Xiong, En-Juan; Li, Jing-Jing; Yuan, Lin-Ling; Yu, Xiao-Qiang; Wang, Yu-Feng

    2014-06-01

    Wolbachia are endosymbionts that infect many insect species. They can manipulate the host's reproduction to increase their own maternal transmission. Cytoplasmic incompatibility (CI) is one such manipulation, which is expressed as embryonic lethality when Wolbachia-infected males mate with uninfected females. However, matings between males and females carrying the same Wolbachia strain result in viable progeny. The molecular mechanisms of CI are currently not clear. We have previously reported that the gene Juvenile hormone-inducible protein 26 (JhI-26) exhibited the highest upregulation in the 3rd instar larval testes of Drosophila melanogaster when infected by Wolbachia. This is reminiscent of an interaction between Wolbachia and juvenile hormone (JH) pathway in flies. Considering that Jhamt gene encodes JH acid methyltransferase, a key regulatory enzyme of JH biosynthesis, and that methoprene-tolerant (Met) has been regarded as the best JH receptor candidate, we first compared the expression of Jhamt and Met between Wolbachia-infected and uninfected fly testes to investigate whether Wolbachia infection influence the JH signaling pathway. We found that the expressions of Jhamt and Met were significantly increased in the presence of Wolbachia, suggesting an interaction of Wolbachia with the JH signaling pathway. Then, we found that overexpression of JhI-26 in Wolbachia-free transgenic male flies caused paternal-effect lethality that mimics the defects associated with CI. JhI-26 overexpressing males resulted in significantly decrease in hatch rate. Surprisingly, Wolbachia-infected females could rescue the egg hatch. In addition, we showed that overexpression of JhI-26 caused upregulation of the male accessory gland protein (Acp) gene CG10433, but not vice versa. This result suggests that JhI-26 may function at the upstream of CG10433. Likewise, overexpression of CG10433 also resulted in paternal-effect lethality. Both JhI-26 and CG10433 overexpressing males

  9. The role of juvenile hormone and insulin/TOR signaling in the growth of Manduca sexta.

    PubMed

    Hatem, Nicole E; Wang, Zhou; Nave, Keelin B; Koyama, Takashi; Suzuki, Yuichiro

    2015-06-25

    In many insect species, fitness trade-offs exist between maximizing body size and developmental speed. Understanding how various species evolve different life history strategies requires knowledge of the physiological mechanisms underlying the regulation of body size and developmental timing. Here the roles of juvenile hormone (JH) and insulin/target of rapamycin (TOR) signaling in the regulation of the final body size were examined in the tobacco hornworm, Manduca sexta. Feeding rapamycin to wild-type larvae decreased the growth rate but did not alter the peak size of the larvae. In contrast, feeding rapamycin to the JH-deficient black mutant larvae caused the larvae to significantly increase the peak size relative to the DMSO-fed control animals by lengthening the terminal growth period. Furthermore, the critical weight was unaltered by feeding rapamycin, indicating that in Manduca, the critical weight is not influenced by insulin/TOR signaling. In addition, post-critical weight starved black mutant Manduca given rapamycin underwent metamorphosis sooner than those that were fed, mimicking the "bail-out mechanism". Our study demonstrates that JH masks the effects of insulin/TOR signaling in the determination of the final body size and that the critical weights in Drosophila and Manduca rely on distinct mechanisms that reflect different life history strategies. Our study also suggests that TOR signaling lengthens the terminal growth period in Manduca as it does in Drosophila, and that JH levels determine the relative contributions of nutrient- and body size-sensing pathways to metamorphic timing.

  10. The effect of juvenile hormone on Polistes wasp fertility varies with cooperative behavior.

    PubMed

    Tibbetts, Elizabeth A; Sheehan, Michael J

    2012-04-01

    Social insects provide good models for studying how and why the mechanisms that underlie reproduction vary, as there is dramatic reproductive plasticity within and between species. Here, we test how the effect of juvenile hormone (JH) on fertility covaries with cooperative behavior in workers and nest-founding queens in the primitively eusocial wasp Polistes metricus. P. metricus foundresses and workers appear morphologically similar and both are capable of reproduction, though there is variation in the extent of social cooperation and the probability of reproduction across castes. Do the endocrine mechanisms that mediate reproduction co-vary with cooperative behavior? We found dramatic differences in the effect of JH on fertility across castes. In non-cooperative nest-founding queens, all individuals responded to JH by increasing their fertility. However, in cooperative workers, the effect of JH on fertility varies with body weight; large workers increase their fertility in response to JH while small workers do not. The variation in JH response may be an adaptation to facilitate resource allocation based on the probability of independent reproduction. This work contrasts with previous studies in closely related Polistes dominulus paper wasps, in which both foundresses and workers form cooperative associations and both castes show similar, condition-dependent JH response. The variation in JH responsiveness within and between species suggests that endocrine responsiveness and the factors influencing caste differentiation are surprisingly evolutionarily labile. Copyright © 2012 Elsevier Inc. All rights reserved.

  11. Juvenile hormone catabolism and oviposition in the codling moth, Cydia pomonella, as functions of age, mating status, and hormone treatment.

    PubMed

    Cole, Tracey J; Ramaswamy, Sonny B; Srinivasan, Asoka; Dorn, Silvia

    2002-01-01

    In vitro catabolism of juvenile hormone (JH) in haemolymph of adult female Cydia pomonella was ascribed mainly to juvenile hormone esterase (JHE) activity. No significant differences were noted between virgin and mated females 0-96 h post-emergence. Changes in JHE activity did not appear dependent upon fluctuations in JH titre; conversely, changes in JHE activity could not explain the changes in JH titres. Maximal JHE activity was recorded at 24 h (331.47 +/- 47.25 pmol/h/microl; 355.93 +/- 36.68 pmol/h/microl, virgin; mated insects, respectively) and preceded the peak in JH titres at 48 h. Topical application of JH II (10 ng-10 microg) or fenoxycarb (50 ng) enhanced JHE activity up to 640 and 56%, respectively. Treatment upon emergence with 10 microg JH II induced enzymic activity for less than 24 h, and when 10 microg JH II or 50 ng fenoxycarb were applied, circulating JH titres returned to control levels within 24 h. Oviposition was highly sensitive to exogenous JH and declined significantly with dosages >100 pg. To allow a degree of oocyte maturation before JH treatment, the hormone was administered at 6, 12, 24, or 48 h post-emergence and/or females were mated. Neither measure "protected" the system; oviposition declined immediately after JH application.

  12. Characterization of the juvenile hormone pathway in the viviparous cockroach, Diploptera punctata.

    PubMed

    Huang, Juan; Marchal, Elisabeth; Hult, Ekaterina F; Tobe, Stephen S

    2015-01-01

    Juvenile hormones (JHs) are key regulators of insect development and reproduction. The JH biosynthetic pathway is known to involve 13 discrete enzymatic steps. In the present study, we have characterized the JH biosynthetic pathway in the cockroach Diploptera punctata. The effect of exogenous JH precursors on JH biosynthesis was also determined. Based on sequence similarity, orthologs for the genes directly involved in the pathway were cloned, and their spatial and temporal transcript profiles were determined. The effect of shutting down the JH pathway in adult female cockroaches was studied by knocking down genes encoding HMG-CoA reductase (HMGR) and Juvenile hormone acid methyltransferase (JHAMT). As a result, oocyte development slowed as a consequence of reduction in JH biosynthesis. Oocyte length, fat body transcription of Vg and ovarian vitellin content significantly decreased. In addition, silencing HMGR and JHAMT resulted in a decrease in the transcript levels of other genes in the pathway.

  13. Characterization of the Juvenile Hormone Pathway in the Viviparous Cockroach, Diploptera punctata

    PubMed Central

    Huang, Juan; Marchal, Elisabeth; Hult, Ekaterina F.; Tobe, Stephen S.

    2015-01-01

    Juvenile hormones (JHs) are key regulators of insect development and reproduction. The JH biosynthetic pathway is known to involve 13 discrete enzymatic steps. In the present study, we have characterized the JH biosynthetic pathway in the cockroach Diploptera punctata. The effect of exogenous JH precursors on JH biosynthesis was also determined. Based on sequence similarity, orthologs for the genes directly involved in the pathway were cloned, and their spatial and temporal transcript profiles were determined. The effect of shutting down the JH pathway in adult female cockroaches was studied by knocking down genes encoding HMG-CoA reductase (HMGR) and Juvenile hormone acid methyltransferase (JHAMT). As a result, oocyte development slowed as a consequence of reduction in JH biosynthesis. Oocyte length, fat body transcription of Vg and ovarian vitellin content significantly decreased. In addition, silencing HMGR and JHAMT resulted in a decrease in the transcript levels of other genes in the pathway. PMID:25706877

  14. Electrochemical impedance spectroscopy for the study of juvenile hormones-recombinant protein interactions.

    PubMed

    Stobiecka, Agata; Dvornyk, Anzhela; Grzelak, Krystyna; Radecka, Hanna

    2008-01-01

    The interactions of recombinant juvenile hormone binding protein (His8-rJHBP) with juvenile hormones (JHs), methoprene and farnesol have been studied with electrochemical impedance spectroscopy (EIS). The protein was immobilized on the dodecanethiol (DDT) modified gold electrodes. Each step of electrode modification has been confirmed with cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The conformation changes of His8-rJHBP upon JHs and methoprene binding have been presented. The EIS determined association constants in the JHs analogs-immobilized His8-rJHBP system indicate that lack of the epoxide moiety in methoprene molecule is not critical for observed high affinity of this compound to the binding region of the His8-rJHBP protein.

  15. Characterization and affinity purification of juvenile hormone esterase from Bombyx mori.

    PubMed

    Shiotsuki, T; Bonning, B C; Hirai, M; Kikuchi, K; Hammock, B D

    2000-08-01

    Juvenile hormone esterase (JHE) from hemolymph of the silkworm moth Bombyx mori was characterized for substrate specificity and inhibitor sensitivity. B. mori JHE hydrolyzed the juvenile hormone surrogate substrate methyl n-heptylthioacetothioate (HEPTAT) more efficiently than p-nitrophenyl acetate and 1-naphthyl acetate substrates widely used to assay total carboxylesterase activity. B. mori JHE was sensitive to 3-octylthio-1,1,1-trifluoro-2-propanone (OTFP), which was developed as a selective inhibitor for lepidopteran JHE, and relatively insensitive to diisopropyl fluorophosphate (DFP), an inhibitor of serine esterases but not of all JHEs. Affinity purification with a trifluoromethyl ketone ligand was more efficient for purification of B. mori JHE than DEAE ion exchange chromatography.

  16. Juvenile hormone regulates vitellogenin gene expression through insulin-like peptide signaling pathway in the red flour beetle, Tribolium castaneum.

    PubMed

    Sheng, Zhentao; Xu, Jingjing; Bai, Hua; Zhu, Fang; Palli, Subba R

    2011-12-09

    Our recent studies identified juvenile hormone (JH) and nutrition as the two key signals that regulate vitellogenin (Vg) gene expression in the red flour beetle, Tribolium castaneum. Juvenile hormone regulation of Vg synthesis has been known for a long time in several insects, but the mechanism of JH action is not known. Experiments were conducted to determine the mechanism of action of these two signals in regulation of Vg gene expression. Injection of bovine insulin or FOXO double-stranded RNA into the previtellogenic, starved, or JH-deficient female adults increased Vg mRNA and protein levels, thereby implicating the pivotal role for insulin-like peptide signaling in the regulation of Vg gene expression and possible cross-talk between JH and insulin-like peptide signaling pathways. Reduction in JH synthesis or its action by RNAi-mediated silencing of genes coding for acid methyltransferase or methoprene-tolerant decreased expression of genes coding for insulin-like peptides (ILPs) and influenced FOXO subcellular localization, resulting in the down-regulation of Vg gene expression. Furthermore, JH application to previtellogenic female beetles induced the expression of genes coding for ILP2 and ILP3, and induced Vg gene expression. FOXO protein expressed in baculovirus system binds to FOXO response element present in the Vg gene promoter. These data suggest that JH functions through insulin-like peptide signaling pathway to regulate Vg gene expression.

  17. Juvenile Hormone Regulates Vitellogenin Gene Expression through Insulin-like Peptide Signaling Pathway in the Red Flour Beetle, Tribolium castaneum*

    PubMed Central

    Sheng, Zhentao; Xu, Jingjing; Bai, Hua; Zhu, Fang; Palli, Subba R.

    2011-01-01

    Our recent studies identified juvenile hormone (JH) and nutrition as the two key signals that regulate vitellogenin (Vg) gene expression in the red flour beetle, Tribolium castaneum. Juvenile hormone regulation of Vg synthesis has been known for a long time in several insects, but the mechanism of JH action is not known. Experiments were conducted to determine the mechanism of action of these two signals in regulation of Vg gene expression. Injection of bovine insulin or FOXO double-stranded RNA into the previtellogenic, starved, or JH-deficient female adults increased Vg mRNA and protein levels, thereby implicating the pivotal role for insulin-like peptide signaling in the regulation of Vg gene expression and possible cross-talk between JH and insulin-like peptide signaling pathways. Reduction in JH synthesis or its action by RNAi-mediated silencing of genes coding for acid methyltransferase or methoprene-tolerant decreased expression of genes coding for insulin-like peptides (ILPs) and influenced FOXO subcellular localization, resulting in the down-regulation of Vg gene expression. Furthermore, JH application to previtellogenic female beetles induced the expression of genes coding for ILP2 and ILP3, and induced Vg gene expression. FOXO protein expressed in baculovirus system binds to FOXO response element present in the Vg gene promoter. These data suggest that JH functions through insulin-like peptide signaling pathway to regulate Vg gene expression. PMID:22002054

  18. Cyp15F1: A novel cytochrome P450 gene linked to juvenile hormone-dependent caste differention in the termite R. flavipes

    USDA-ARS?s Scientific Manuscript database

    Termites are eusocial insects that perform social interactions that facilitate chemical signaling. Previous research identified two cytochrome P450s that have homology to other insect p450s responsible for the production of juvenile hormone. Juvenile hormone is an important morphogenic hormone tha...

  19. Juvenile Hormone Regulates the Expression of Drosophila Epac– a Guanine Nucleotide Exchange Factor for Rap1 Small GTPase

    USDA-ARS?s Scientific Manuscript database

    The juvenile hormones (JH) are a key group of insect hormones involved in regulating larval development and adult reproductive processes. Although well-studied from the physiological standpoint, the molecular actions of JH remain unclear. Using cDNA microchip array technology, we previously identifi...

  20. Resistance to juvenile hormone and an insect growth regulator in Drosophila is associated with an altered cytosolic juvenile hormone-binding protein

    SciTech Connect

    Shemshedini, L.; Wilson, T.G. )

    1990-03-01

    The Met mutant of Drosophila melanogaster is highly resistant to juvenile hormone III (JH III) or its chemical analog, methoprene, an insect growth regulator. Five major mechanisms of insecticide resistance were examined in Met and susceptible Met{sup +} flies. These two strains showed only minor differences when penetration, excretion, tissue sequestration, or metabolism of ({sup 3}H)JH III was measured. In contrast, when we examined JH III binding by a cytosolic binding protein from a JH target tissue, Met strains had a 10-fold lower binding affinity than did Met{sup +} strains. Studies using deficiency-bearing chromosomes provide strong evidence that the Met locus controls the binding protein characteristics and may encode the protein. These studies indicate that resistance in Met flies results from reduced binding affinity of a cytosolic binding protein for JH III.

  1. Juvenile hormone-binding proteins of Melanoplus bivittatus identified by EFDA photoaffinity labeling

    SciTech Connect

    Winder, B.S.

    1988-01-01

    Proteins that bind juvenile hormone in the hemolymph and fat body of the grasshopper, Melanoplus bivittatus were identified by photoaffinity labeling with radiolabeled epoxyfarnesyl diazoacetate ({sup 3}H-EFDA), and were characterized by electrophoretic analysis. A protocol was developed which allowed detection of {sup 3}H-EFDA that was covalently linked to proteins upon exposure to ultraviolet light at 254 nm. Quantification of protein-linked {sup 3}H-EFDA by liquid scintillation spectrometry took advantage of the differential solubility of unlinked {sup 3}H-EFDA in toluene alone, and of the protein-linked {sup 3}H-EFDA in toluene plus the detergent, Triton X-100. Competition between EFDA and juvenile hormone (JH) for binding to JH-specific binding sites was measured by hydroxyapatite protein binding assays in the presence of radiolabeled JH or EFDA and competing non-radiolabeled hormone. The protein-linked EFDA was detected on fluorograms of SDS or nondenaturing polyacrylamide gels (PAGE), and by liquid scintillation spectrometry of membranes to which the proteins had been electrophoretically transferred. Proteins which specifically bound JH were identified by photolabeling proteins in the presence and absence of nonlabeled JH-III.

  2. Insecticidal juvenile hormone analogs stimulate the production of male offspring in the crustacean Daphnia magna.

    PubMed

    Olmstead, Allen W; LeBlanc, Gerald A

    2003-06-01

    Juvenile hormone analogs (JHAs) represent a class of insecticides that were designed specifically to disrupt endocrine-regulated processes relatively unique to insects. Recently we demonstrated that the crustacean juvenoid hormone methyl farnesoate programs oocytes of the crustacean Daphnia magna to develop into males. We hypothesized that insecticidal JHAs might mimic the action of methyl farnesoate, producing altered sex ratios of offspring. Daphnids were exposed chronically (3 weeks) to sublethal concentrations of methyl farnesoate, the JHA pyriproxyfen, and several nonjuvenoid chemicals to discern whether excess male offspring production is a generic response to stress or a specific response to juvenoid hormones. Only methyl farnesoate and pyriproxyfen increased the percentage of males produced by exposed maternal organisms. As previously reported with methyl farnesoate, acute exposure (24 hr) to either pyriproxyfen or the JHA methoprene caused oocytes maturing in the ovary to develop into males. We performed experiments to determine whether combined effects of a JHA and methyl farnesoate conformed better to a model of concentration addition (indicative of same mechanism of action) or independent joint action (indicative of different mechanisms of action). Combined effects conformed better to the concentration-addition model, although some synergy, of unknown etiology, was evident between the insecticides and the hormone. These experiments demonstrate that insecticidal JHAs mimic the action of the crustacean juvenoid hormone methyl farnesoate, resulting in the inappropriate production of male offspring. The occurrence of such an effect in the environment could have dire consequences on susceptible crustacean populations.

  3. Evidence for differential biosynthesis of juvenile hormone (and related) sesquiterpenoids in Drosophila melanogaster.

    PubMed

    Bendena, William G; Zhang, Jinrui; Burtenshaw, Sally M; Tobe, Stephen S

    2011-05-15

    Previous studies in Drosophila melanogaster have demonstrated that biosynthesis and regulation of juvenile hormone bisepoxide (JHB(3)) may not be coordinated with that of juvenile hormone (JH III). In this study, we have used the radiochemical assay to confirm the coordinated developmental sesquiterpenoid profile during adult life and analyze the effect of farnesol and farnesoic acid addition on methyl farnesoate, JH III and JHB(3) production by isolated ring glands of Drosophila third instar larvae or corpora allata of adult females. Application of exogenous farnesol or farnesoic acid to glands in vitro stimulated MF and JH III biosynthesis in both larvae and adults. Farnesol and farnesoic acid were inhibitory to JHB(3) biosynthesis in larvae. N-acetyl-geranyl-L-cysteine (NAGC) and S-farnesyl-thioacetic acid (SFTA) are farnesyl pyrophosphatase inhibitors that have specificity towards two different ring gland phosphatases. NAGC and SFTA had no effect on MF or JH III biosynthesis, whereas SFTA inhibited JHB(3) biosynthesis. SFTA shows specificity for a ring gland phosphatase, Phos2680, which has not been previously implicated as a contributor to JHB(3) biosynthesis. This finding suggests that farnesol production occurs in two alternate pools; one pool utilized for MF and JH III production and the other for JHB(3) production. Finally, we have used the UAS-GAL4 system in Drosophila to express juvenile hormone acid methyltransferase (JHAMT) in vivo. In contrast to in vitro studies, JHAMT expression had no effect on MF or JH III biosynthesis but stimulated JHB(3) in both larvae and adults.

  4. The POU factor ventral veins lacking/Drifter directs the timing of metamorphosis through ecdysteroid and juvenile hormone signaling.

    PubMed

    Cheng, CeCe; Ko, Amy; Chaieb, Leila; Koyama, Takashi; Sarwar, Prioty; Mirth, Christen K; Smith, Wendy A; Suzuki, Yuichiro

    2014-06-01

    Although endocrine changes are known to modulate the timing of major developmental transitions, the genetic mechanisms underlying these changes remain poorly understood. In insects, two developmental hormones, juvenile hormone (JH) and ecdysteroids, are coordinated with each other to induce developmental changes associated with metamorphosis. However, the regulation underlying the coordination of JH and ecdysteroid synthesis remains elusive. Here, we examined the function of a homolog of the vertebrate POU domain protein, Ventral veins lacking (Vvl)/Drifter, in regulating both of these hormonal pathways in the red flour beetle, Tribolium castaneum (Tenebrionidae). RNA interference-mediated silencing of vvl expression led to both precocious metamorphosis and inhibition of molting in the larva. Ectopic application of a JH analog on vvl knockdown larvae delayed the onset of metamorphosis and led to a prolonged larval stage, indicating that Vvl acts upstream of JH signaling. Accordingly, vvl knockdown also reduced the expression of a JH biosynthesis gene, JH acid methyltransferase 3 (jhamt3). In addition, ecdysone titer and the expression of the ecdysone response gene, hormone receptor 3 (HR3), were reduced in vvl knockdown larvae. The expression of the ecdysone biosynthesis gene phantom (phm) and spook (spo) were reduced in vvl knockdown larvae in the anterior and posterior halves, respectively, indicating that Vvl might influence ecdysone biosynthesis in both the prothoracic gland and additional endocrine sources. Injection of 20-hydroxyecdysone (20E) into vvl knockdown larvae could restore the expression of HR3 although molting was never restored. These findings suggest that Vvl coordinates both JH and ecdysteroid biosynthesis as well as molting behavior to influence molting and the timing of metamorphosis. Thus, in both vertebrates and insects, POU factors modulate the production of major neuroendocrine regulators during sexual maturation.

  5. The POU Factor Ventral Veins Lacking/Drifter Directs the Timing of Metamorphosis through Ecdysteroid and Juvenile Hormone Signaling

    PubMed Central

    Chaieb, Leila; Koyama, Takashi; Sarwar, Prioty; Mirth, Christen K.; Smith, Wendy A.; Suzuki, Yuichiro

    2014-01-01

    Although endocrine changes are known to modulate the timing of major developmental transitions, the genetic mechanisms underlying these changes remain poorly understood. In insects, two developmental hormones, juvenile hormone (JH) and ecdysteroids, are coordinated with each other to induce developmental changes associated with metamorphosis. However, the regulation underlying the coordination of JH and ecdysteroid synthesis remains elusive. Here, we examined the function of a homolog of the vertebrate POU domain protein, Ventral veins lacking (Vvl)/Drifter, in regulating both of these hormonal pathways in the red flour beetle, Tribolium castaneum (Tenebrionidae). RNA interference-mediated silencing of vvl expression led to both precocious metamorphosis and inhibition of molting in the larva. Ectopic application of a JH analog on vvl knockdown larvae delayed the onset of metamorphosis and led to a prolonged larval stage, indicating that Vvl acts upstream of JH signaling. Accordingly, vvl knockdown also reduced the expression of a JH biosynthesis gene, JH acid methyltransferase 3 (jhamt3). In addition, ecdysone titer and the expression of the ecdysone response gene, hormone receptor 3 (HR3), were reduced in vvl knockdown larvae. The expression of the ecdysone biosynthesis gene phantom (phm) and spook (spo) were reduced in vvl knockdown larvae in the anterior and posterior halves, respectively, indicating that Vvl might influence ecdysone biosynthesis in both the prothoracic gland and additional endocrine sources. Injection of 20-hydroxyecdysone (20E) into vvl knockdown larvae could restore the expression of HR3 although molting was never restored. These findings suggest that Vvl coordinates both JH and ecdysteroid biosynthesis as well as molting behavior to influence molting and the timing of metamorphosis. Thus, in both vertebrates and insects, POU factors modulate the production of major neuroendocrine regulators during sexual maturation. PMID:24945490

  6. Genistein excitation of gonadotrophin-releasing hormone neurones in juvenile female mice.

    PubMed

    Bhattarai, J P; Abrahám, I M; Han, S K

    2013-05-01

    We investigated the effects of the phytoestrogen genistein on gonadotrophin-releasing hormone (GnRH) neurones using single-cell electrophysiology on GnRH-green fluorescent protein (GFP) transgenic juvenile female mice. Perforated patch-clamp recordings from GnRH-GFP neurones showed that approximately 83% of GnRH neurones responded to 30 μm genistein with a markedly prolonged membrane depolarisation. This effect not only persisted in the presence of tetrodotoxin, but also in the presence of amino acid receptor antagonists, indicating the direct site of action on postsynaptic GnRH neurones. Using a voltage clamp technique, we found that 30 μm genistein increased the frequency of synaptic current of GnRH neurones clamped at -60 mV in the presence of glutamate receptor blocker but not GABAA receptor blocker. Pre-incubation of GnRH neurones with 30 μm genistein enhanced kisspeptin-induced membrane depolarisation and firing. GnRH neurones of juvenile mice injected with genistein in vivo showed an enhanced kisspeptin response compared to vehicle-injected controls. The transient receptor potential channel (TRPC) blocker 2-aminoethoxydiphenyl borate (75 μm) blocked the genistein-mediated response on GnRH neurones. These results demonstrate that genistein acts on GnRH neurones in juvenile female mice to induce excitation via GABA neurotransmission and TRPCs to enhance kisspeptin-induced activation. © 2013 British Society for Neuroendocrinology.

  7. Interplay between insulin signaling, juvenile hormone, and vitellogenin regulates maternal effects on polyphenism in ants

    PubMed Central

    Libbrecht, Romain; Corona, Miguel; Wende, Franziska; Azevedo, Dihego O.; Serrão, Jose E.; Keller, Laurent

    2013-01-01

    Polyphenism is the phenomenon in which alternative phenotypes are produced by a single genotype in response to environmental cues. An extreme case is found in social insects, in which reproductive queens and sterile workers that greatly differ in morphology and behavior can arise from a single genotype. Experimental evidence for maternal effects on caste determination, the differential larval development toward the queen or worker caste, was recently documented in Pogonomyrmex seed harvester ants, in which only colonies with a hibernated queen produce new queens. However, the proximate mechanisms behind these intergenerational effects have remained elusive. We used a combination of artificial hibernation, hormonal treatments, gene expression analyses, hormone measurements, and vitellogenin quantification to investigate how the combined effect of environmental cues and hormonal signaling affects the process of caste determination in Pogonomyrmex rugosus. The results show that the interplay between insulin signaling, juvenile hormone, and vitellogenin regulates maternal effects on the production of alternative phenotypes and set vitellogenin as a likely key player in the intergenerational transmission of information. This study reveals how hibernation triggers the production of new queens in Pogonomyrmex ant colonies. More generally, it provides important information on maternal effects by showing how environmental cues experienced by one generation can translate into phenotypic variation in the next generation. PMID:23754378

  8. Sex Determination in Bees. IV. Genetic Control of Juvenile Hormone Production in MELIPONA QUADRIFASCIATA (Apidae)

    PubMed Central

    Kerr, Warwick Estevam; Akahira, Yukio; Camargo, Conceição A.

    1975-01-01

    Cell number and volume of corpora allata was determined for 8 phases of development, the first prepupal stage to adults 30 days old, in the social Apidae Melipona quadrifasciata. In the second prepupal stage a strong correlation was found between cell number and body weight ( r=0.651**), and cell number and corpora allata volume in prepupal stage (r=0.535*), which indicates that juvenile hormone has a definite role in caste determination in Melipona. The distribution of the volume of corpus allatum suggest a 3:1 segregation between bees with high volume of corpora allata against low and medium volume. This implies that genes xa and xb code for an enzyme that directly participates in juvenile hormone production. It was also concluded that the number of cells in the second prepupal stage is more important than the weight of the prepupa for caste determination. A scheme summarizing the genic control of sex and caste determination in Melipona bees in the prepupal phase is given. PMID:1213273

  9. BLACK SPOT INFESTATION IN JUVENILE COHO SALMON AND THE INFLUENCE OF OREGON COASTAL STREAM SUMMER TEMPERATURES

    EPA Science Inventory

    Freshwater survival and growth of juvenile salmon are affected by many factors, including high summer temperatures and other stressors such as parasitism. Delayed or suppressed growth related to stress can influence subsequent survival of juvenile salmonids in freshwater and mar...

  10. Aspergillus nidulans Synthesize Insect Juvenile Hormones upon Expression of a Heterologous Regulatory Protein and in Response to Grazing by Drosophila melanogaster Larvae

    PubMed Central

    Rohlfs, Marko; Anyaogu, Diana Chinyere; Nielsen, Jakob Blæsbjerg; Gotfredsen, Charlotte Held; Andersen, Mikael Rørdam; Hansen, Bjarne Gram; Mortensen, Uffe Hasbro; Larsen, Thomas Ostenfeld

    2013-01-01

    Secondary metabolites are known to serve a wide range of specialized functions including communication, developmental control and defense. Genome sequencing of several fungal model species revealed that the majority of predicted secondary metabolite related genes are silent in laboratory strains, indicating that fungal secondary metabolites remain an underexplored resource of bioactive molecules. In this study, we combine heterologous expression of regulatory proteins in Aspergillus nidulans with systematic variation of growth conditions and observe induced synthesis of insect juvenile hormone-III and methyl farnesoate. Both compounds are sesquiterpenes belonging to the juvenile hormone class. Juvenile hormones regulate developmental and metabolic processes in insects and crustaceans, but have not previously been reported as fungal metabolites. We found that feeding by Drosophila melanogaster larvae induced synthesis of juvenile hormone in A. nidulans indicating a possible role of juvenile hormone biosynthesis in affecting fungal-insect antagonisms. PMID:23991191

  11. Identification of two juvenile hormone inducible transcription factors from the silkworm, Bombyx mori.

    PubMed

    Matsumoto, Hitoshi; Ueno, Chihiro; Nakamura, Yuki; Kinjoh, Terunori; Ito, Yuka; Shimura, Sachiko; Noda, Hiroaki; Imanishi, Shigeo; Mita, Kazuei; Fujiwara, Haruhiko; Hiruma, Kiyoshi; Shinoda, Tetsuro; Kamimura, Manabu

    2015-09-01

    Juvenile hormone (JH) regulates many physiological processes in insects. However, the signal cascades in which JH is active have not yet been fully elucidated, particularly in comparison to another major hormone ecdysteroid. Here we identified two JH inducible transcription factors as candidate components of JH signaling pathways in the silkworm, Bombyx mori. DNA microarray analysis showed that expression of two transcription factor genes, E75 and Enhancer of split mβ (E(spl)mβ), was induced by juvenile hormone I (JH I) in NIAS-Bm-aff3 cells. Real time RT-PCR analysis confirmed that expression of four E75 isoforms (E75A, E75B, E75C and E75D) and E(spl)mβ was 3-8 times greater after JH I addition. Addition of the protein synthesis inhibitor cycloheximide did not suppress JH-induced expression of the genes, indicating that they were directly induced by JH. JH-induced expression of E75 and E(spl)mβ was also observed in four other B. mori cell lines and in larval hemocytes of final instar larvae. Notably, E75A expression was induced very strongly in larval hemocytes by topical application of the JH analog fenoxycarb; the level of induced expression was comparable to that produced by feeding larvae with 20-hydroxyecdysone. These results suggest that E75 and E(spl)mβ are general and direct target genes of JH and that the transcription factors encoded by these genes play important roles in JH signaling.

  12. Depletion of juvenile hormone esterase extends larval growth in Bombyx mori.

    PubMed

    Zhang, Zhongjie; Liu, Xiaojing; Shiotsuki, Takahiro; Wang, Zhisheng; Xu, Xia; Huang, Yongping; Li, Muwang; Li, Kai; Tan, Anjiang

    2017-02-01

    Two major hormones, juvenile hormone (JH) and 20-hydroxyecdysone (20E), regulate insect growth and development according to their precisely coordinated titres, which are controlled by both biosynthesis and degradation pathways. Juvenile hormone esterase (JHE) is the primary JH-specific degradation enzyme that plays a key role in regulating JH titers, along with JH epoxide hydrolase (JHEH) and JH diol kinase (JHDK). In the current study, a loss-of-function analysis of JHE in the silkworm, Bombyx mori, was performed by targeted gene disruption using the transgenic CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/RNA-guided Cas9 nucleases) system. Depletion of B. mori JHE (BmJHE) resulted in the extension of larval stages, especially the penultimate and ultimate larval stages, without deleterious effects to silkworm physiology. The expression of JHEH and JHDK was upregulated in mutant animals, indicating the existence of complementary routes in the JH metabolism pathway in which inactivation of one enzyme will activate other enzymes. RNA-Seq analysis of mutant animals revealed that genes involved in protein processing in the endoplasmic reticulum and in amino acid metabolism were affected by BmJHE depletion. Depletion of JHE and subsequent delayed JH metabolism activated genes in the TOR pathway, which are ultimately responsible for extending larval growth. The transgenic Cas9 system used in the current study provides a promising approach for analysing the actions of JH, especially in nondrosophilid insects. Furthermore, prolonging larval stages produced larger larvae and cocoons, which is greatly beneficial to silk production. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. 20-Hydroxyecdysone stimulation of juvenile hormone biosynthesis by the mosquito corpora allata.

    PubMed

    Areiza, Maria; Nouzova, Marcela; Rivera-Perez, Crisalejandra; Noriega, Fernando G

    2015-09-01

    Juvenile hormone III (JH) is synthesized by the corpora allata (CA) and plays a key role in mosquito development and reproduction. JH titer decreases in the last instar larvae allowing pupation and metamorphosis to progress. As the anti-metamorphic role of JH comes to an end, the CA of the late pupa (or pharate adult) becomes again "competent" to synthesize JH, which plays an essential role orchestrating reproductive maturation. 20-hydroxyecdysone (20E) prepares the pupae for ecdysis, and would be an ideal candidate to direct a developmental program in the CA of the pharate adult mosquito. In this study, we provide evidence that 20E acts as an age-linked hormonal signal, directing CA activation in the mosquito pupae. Stimulation of the inactive brain-corpora allata-corpora cardiaca complex (Br-CA-CC) of the early pupa (24 h before adult eclosion or -24 h) in vitro with 20E resulted in a remarkable increase in JH biosynthesis, as well as increase in the activity of juvenile hormone acid methyltransferase (JHAMT). Addition of methyl farnesoate but not farnesoic acid also stimulated JH synthesis by the Br-CA-CC of the -24 h pupae, proving that epoxidase activity is present, but not JHAMT activity. Separation of the CA-CC complex from the brain (denervation) in the -24 h pupae also activated JH synthesis. Our results suggest that an increase in 20E titer might override an inhibitory effect of the brain on JH synthesis, phenocopying denervation. All together these findings provide compelling evidence that 20E acts as a developmental signal that ensures proper reactivation of JH synthesis in the mosquito pupae.

  14. Nutrient limitation results in juvenile hormone-mediated resorption of previtellogenic ovarian follicles in mosquitoes.

    PubMed

    Clifton, Mark E; Noriega, Fernando G

    2011-09-01

    Juvenile hormone (JH) is a central hormonal regulator of previtellogenic development in female Aedes aegypti mosquitoes. JH levels are low at eclosion and increase during the first day after adult emergence. This initial rise in JH is essential for female reproductive maturation. After previtellogenic maturation is complete, the mosquito enters a 'state-of-arrest' during which JH synthesis continues at a slower pace and further ovary development is repressed until a blood meal is taken. By examining the relationships between juvenile hormone, follicular resorption and nutrition in A. aegypti, we were able to define a critical role of JH during the previtellogenic resting stage. The rate of follicular resorption in resting stage mosquitoes is dependent on nutritional quality. Feeding water alone caused the rate of follicular resorption to reach over 20% by day 7 after emergence. Conversely, feeding a 20% sucrose solution caused resorption to remain below 5% during the entire experimental period. Mosquitoes fed 3% sucrose show rates of resorption intermediate between water and 20% sucrose and only reached 10% by day 7 after emergence. Follicular resorption is related to JH levels. Ligated abdomens separated from a source of JH (the corpora allata) showed an increase in resorption comparable to similarly aged starved mosquitoes (16%). Resorption in ligated abdomens was reduced to 6% by application of methoprene. The application of methoprene was also sufficient to prevent resorption in intact mosquitoes starved for 48 h (14% starved vs. 4% starved with methoprene). Additionally, active caspases were localized to resorbing follicles indicating that an apoptotic cell-death mechanism is responsible for follicular resorption during the previtellogenic resting stage. Taken together, these results indicate that JH mediates reproductive trade-offs in resting stage mosquitoes in response to nutrition.

  15. Nutrient limitation results in juvenile hormone-mediated resorption of previtellogenic ovarian follicles in mosquitoes

    PubMed Central

    Clifton, Mark E.; Noriega, Fernando G.

    2011-01-01

    Juvenile hormone (JH) is a central hormonal regulator of previtellogenic development in female Aedes aegypti mosquitoes. JH levels are low at eclosion and increase during the first day after adult emergence. This initial rise in JH is essential for female reproductive maturation. After previtellogenic maturation is complete, the mosquito enters a ‘state-of-arrest’ during which JH synthesis continues at a slower pace and further ovary development is repressed until a blood meal is taken. By examining the relationships between juvenile hormone, follicular resorption and nutrition in A. aegypti, we were able to define a critical role of JH during the previtellogenic resting stage. The rate of follicular resorption in resting stage mosquitoes is dependent on nutritional quality. Feeding water alone caused the rate of follicular resorption to reach over 20% by day 7 after emergence. Conversely, feeding a 20% sucrose solution caused resorption to remain below 5% during the entire experimental period. Mosquitoes fed 3% sucrose show rates of resorption intermediate between water and 20% sucrose and only reached 10% by day 7 after emergence. Follicular resorption is related to JH levels. Ligated abdomens separated from a source of JH (the corpora allata) showed an increase in resorption comparable to similarly aged starved mosquitoes (16%). Resorption in ligated abdomens was reduced to 6% by application of methoprene. The application of methoprene was also sufficient to prevent resorption in intact mosquitoes starved for 48 hours (14% starved vs. 4% starved with methoprene). Additionally, active caspases were localized to resorbing follicles indicating that an apoptotic cell-death mechanism is responsible for follicular resorption during the previtellogenic resting stage. Taken together, these results indicate that JH mediates reproductive trade-offs in resting stage mosquitoes in response to nutrition. PMID:21708165

  16. The glutathione-related detoxication responses to juvenile and ecdysone hormones in Galleria mellonella.

    PubMed

    Tarhan, Leman; Kayalı, Hülya Ayar; Karacali, Sabire

    2013-08-01

    The effect of 20-hydroxyecdysone (20E) and juvenile hormone (JH) on the glutathione pathway of the greater wax moth Galleria mellonella (Lepidoptera: Pyralidae) was determined by investigating glutathione peroxidase (GSH-Px), glutathione S-transferases (GST), and glutathione reductase (GR) activities as well as reduced and oxidized glutathione (GSH and GSSG) content with respect to developmental stage. The continuous decreases of GSH-Px and GST activities dependent on the growth period of G. mellonella occurred in JH and 20E groups over and under their controls, respectively. While the GR activities of G. mellonella showed increases in young pupa (YP) for both control and in old larvae (OL) for the 20E groups after the minimum at these periods, they also increased after old pupa (OP) for the JH group with a maximum in OL period. Although GR activity levels in the JH group were significantly higher compared with controls and 20E groups up to OP period, the activity levels for the control and 20E groups were higher than those of the JH group at adult (AD) and old pupa (OP) periods, respectively. In spite of increases in the GR activity of 20E and control groups of G. mellonella, decreased GSH and increased GSSG levels were observed at aging period. GSH levels in the JH group reached a maximum at prepupa (PP) and then decreased with non-significant changes from OL to AD period. According to the results, GSH and GSSG levels, as well as GSH/GSSG ratios, were below and over control levels in 20E and JH groups, respectively, during all of the investigated developmental stages. On the contrary, the LPO levels were higher than the control for 20E and lower for the JH groups during the developmental period. These results show that while ecdysone hormone has a negative effect on the glutathione-related detoxication capacity of G. mellonella, the juvenile hormone has a positive effect on this process.

  17. Juvenile hormone titer in capped worker brood of Apis mellifera and reproduction in the bee mite Varroa jacobsoni.

    PubMed

    Rosenkranz, P; Rachinsky, A; Strambi, A; Strambi, C; Röpstorf, P

    1990-05-01

    Juvenile hormone (JH) titers were recorded from fifth instar worker larvae of Apis mellifera carnica, Apis mellifera lamarckii, and Africanized honeybees kept under temperate and tropical climatic conditions. No differences in hormone titer according to honeybee race or climatic conditions were determined. However, the rate of reproduction of the ectoparasitic mite, Varroa jacobsoni, on larvae of the different honeybee races was highly variable. The possible role of honeybee JH in control of the parasite's reproduction is discussed.

  18. Juvenile hormone receptors in insect larval epidermis: Identification by photoaffinity labeling

    SciTech Connect

    Palli, S.R.; Osir, E.O.; Edwards, M.; Hiruma, K.; Riddiford, L.M. ); Eng, W.; Boehm, M.F.; Kulscar, P.; Ujvary, I.; Prestwich, G.D. )

    1990-01-01

    Tritiated photoaffinity analogs of the natural lepidopteran juvenile hormones, JH I and II (epoxy({sup 3}H)bishomofarnesyl diazoacetate (({sup 3}H)EHDA) and epoxy({sup 3}H)homofarnesyl diazoacetate (({sup 3}H)EHDA)), and of the JH analog methoprene (({sup 3}H)methoprene diazoketone (({sup 3}H)MDK)) were synthesized and used to identify specific JH binding proteins in the larval epidermis of the tobacco hornworm (Manduca sexta). EBDA and EHDA specifically photolabeled a 29-kDa nuclear protein (pI 5.8). This protein and a second 29-kDa protein (pI 6.0) were labeled by MDK, but excess unlabeled methoprene or MDK only prevented binding to the latter. These 29-kDa proteins are also present in larval fat body but not in epidermis from either wandering stage or allatectomized larvae, which lack high-affinity JH binding sites. A 29-kDa nuclear protein with the same developmental specificity as this JH binder bound the DNA of two larval endocuticle genes. A 38-kDa cytosolic protein was also specifically photolabeled by these photoaffinity analogs. The 29-kDa nuclear protein is likely the high-affinity receptor for JH that mediates its genomic action, whereas the 38-kDa cytosolic protein may serve as an intracellular carrier for these highly lipophilic hormones and hormone analogs.

  19. Steroid hormone inactivation is required during the juvenile-adult transition in Drosophila.

    PubMed

    Rewitz, Kim F; Yamanaka, Naoki; O'Connor, Michael B

    2010-12-14

    Steroid hormones are systemic signaling molecules that regulate juvenile-adult transitions in both insects and mammals. In insects, pulses of the steroid hormone 20-hydroxyecdysone (20E) are generated by increased biosynthesis followed by inactivation/clearance. Although mechanisms that control 20E synthesis have received considerable recent attention, the physiological significance of 20E inactivation remains largely unknown. We show that the cytochrome P450 Cyp18a1 lowers 20E titer during the Drosophila prepupal to pupal transition. Furthermore, this reduction of 20E levels is a prerequisite to induce βFTZ-F1, a key factor in the genetic hierarchy that controls early metamorphosis. Resupplying βFTZ-F1 rescues Cyp18a1-deficient prepupae. Because Cyp18a1 is 20E-inducible, it appears that the increased production of steroid is responsible for its eventual decline, thereby generating the regulatory pulse required for proper temporal progression of metamorphosis. The coupling of hormone clearance to βFTZ-F1 expression suggests a general mechanism by which transient signaling drives unidirectional progression through a multistep process.

  20. Ligand-binding properties of a juvenile hormone receptor, Methoprene-tolerant

    PubMed Central

    Charles, Jean-Philippe; Iwema, Thomas; Epa, V. Chandana; Takaki, Keiko; Rynes, Jan; Jindra, Marek

    2011-01-01

    Juvenile hormone (JH) is a sesquiterpenoid of vital importance for insect development, yet the molecular basis of JH signaling remains obscure, mainly because a bona fide JH receptor has not been identified. Mounting evidence points to the basic helix–loop–helix (bHLH)/Per-Arnt-Sim (PAS) domain protein Methoprene-tolerant (Met) as the best JH receptor candidate. However, details of how Met transduces the hormonal signal are missing. Here, we demonstrate that Met specifically binds JH III and its biologically active mimics, methoprene and pyriproxyfen, through its C-terminal PAS domain. Substitution of individual amino acids, predicted to form a ligand-binding pocket, with residues possessing bulkier side chains reduces JH III binding likely because of steric hindrance. Although a mutation that abolishes JH III binding does not affect a Met–Met complex that forms in the absence of methoprene, it prevents both the ligand-dependent dissociation of the Met–Met dimer and the ligand-dependent interaction of Met with its partner bHLH-PAS protein Taiman. These results show that Met can sense the JH signal through direct, specific binding, thus establishing a unique class of intracellular hormone receptors. PMID:22167806

  1. Ligand-binding properties of a juvenile hormone receptor, Methoprene-tolerant.

    PubMed

    Charles, Jean-Philippe; Iwema, Thomas; Epa, V Chandana; Takaki, Keiko; Rynes, Jan; Jindra, Marek

    2011-12-27

    Juvenile hormone (JH) is a sesquiterpenoid of vital importance for insect development, yet the molecular basis of JH signaling remains obscure, mainly because a bona fide JH receptor has not been identified. Mounting evidence points to the basic helix-loop-helix (bHLH)/Per-Arnt-Sim (PAS) domain protein Methoprene-tolerant (Met) as the best JH receptor candidate. However, details of how Met transduces the hormonal signal are missing. Here, we demonstrate that Met specifically binds JH III and its biologically active mimics, methoprene and pyriproxyfen, through its C-terminal PAS domain. Substitution of individual amino acids, predicted to form a ligand-binding pocket, with residues possessing bulkier side chains reduces JH III binding likely because of steric hindrance. Although a mutation that abolishes JH III binding does not affect a Met-Met complex that forms in the absence of methoprene, it prevents both the ligand-dependent dissociation of the Met-Met dimer and the ligand-dependent interaction of Met with its partner bHLH-PAS protein Taiman. These results show that Met can sense the JH signal through direct, specific binding, thus establishing a unique class of intracellular hormone receptors.

  2. Juvenile hormone receptors in insect larval epidermis: identification by photoaffinity labeling.

    PubMed Central

    Palli, S R; Osir, E O; Eng, W; Boehm, M F; Edwards, M; Kulcsar, P; Ujvary, I; Hiruma, K; Prestwich, G D; Riddiford, L M

    1990-01-01

    Tritiated photoaffinity analogs of the natural lepidopteran juvenile hormones, JH I and II [epoxy[3H]bishomofarnesyl diazoacetate ([3H]EBDA) and epoxy[3H]homofarnesyl diazoacetate ([3H]EHDA)], and of the JH analog methoprene [[3H]methoprene diazoketone ([3H]MDK)] were synthesized and used to identify specific JH binding proteins in the larval epidermis of the tobacco hornworm (Manduca sexta). EBDA and EHDA specifically photolabeled a 29-kDa nuclear protein (pI 5.8). This protein and a second 29-kDa protein (pI 6.0) were labeled by MDK, but excess unlabeled methoprene or MDK only prevented binding to the latter. These 29-kDa proteins are also present in larval fat body but not in epidermis from either wandering stage or allatectomized larvae, which lack high-affinity JH binding sites. A 29-kDa nuclear protein with the same developmental specificity as this JH binder bound the DNA of two larval endocuticle genes. A 38-kDa cytosolic protein was also specifically photolabeled by these photoaffinity analogs. The 29-kDa nuclear protein is likely the high-affinity receptor for JH that mediates its genomic action, whereas the 38-kDa cytosolic protein may serve as an intracellular carrier for these highly lipophilic hormones and hormone analogs. Images PMID:11607060

  3. Overexpression of Drosophila juvenile hormone esterase binding protein results in anti-JH effects and reduced pheromone abundance

    USDA-ARS?s Scientific Manuscript database

    The titer of juvenile hormone (JH), which has wide ranging physiological effects in insects, is regulated in part by JH esterase (JHE). We show that overexpression in Drosophila melanogaster of the JHE binding protein, DmP29 results in a series of apparent anti-JH effects. We hypothesize that DmP29 ...

  4. Control of larval and egg development in Aedes aegypti with Ribonucleic acid interference (RNAi) against juvenile hormone acid methyl transferase

    USDA-ARS?s Scientific Manuscript database

    Ribonucleic acid interference (RNAi) is a powerful approach for elucidating gene functions in a variety of organisms, including mosquitoes and many other insects. Little has been done, however, to harness this approach in order to control adult and larval mosquitoes. Juvenile hormone (JH) plays a pi...

  5. Precocious sexual signalling and mating in Anastrepha fraterculus (Diptera: Tephritidae) sterile males achieved through juvenile hormone treatment and protein supplements

    USDA-ARS?s Scientific Manuscript database

    Sexual maturation of Anastrepha fraterculus is a long process. Methoprene (a mimic of juvenile hormone) considerably reduces the time for sexual maturation in males. However, in other Anastrepha species, this effect depends on protein intake at the adult stage. Here, we evaluated the mating competit...

  6. Brain sex differences and hormone influences

    PubMed Central

    Tobet, Stuart; Knoll, J. Gabriel; Hartshorn, Cheryl; Aurand, Emily; Stratton, Matthew; Kumar, Pankaj; Searcy, Brian; McClellan, Kristy

    2009-01-01

    Sex differences in the nervous system come in many forms. Although a majority of sexually dimorphic characteristics in brain have been described in older animals, mechanisms that determine sexually differentiated brain characteristics often operate during critical perinatal periods. Both genetic and hormonal factors likely contribute to physiological mechanisms in development to generate the ontogeny of sexual dimorphisms in brain. Relevant mechanisms may include neurogenesis, cell migration, cell differentiation, cell death, axon guidance and synaptogenesis. On a molecular level, there are several ways to categorize factors that drive brain development. These range from the actions of transcription factors in cell nuclei that regulate the expression of genes that control cell development and differentiation, to effector molecules that directly contribute to signaling from one cell to another. In addition, several peptides or proteins in these and other categories might be referred to as “biomarkers” of sexual differentiation with undetermined functions in development or adulthood. While a majority of sex differences are revealed as a direct consequence of hormone actions, some may only be revealed following genetic or environmental disruption. Sex differences in cell positions in the developing hypothalamus, and steroid hormone influences on cell movements in vitro, suggest that cell migration may be one target for early molecular actions that impact brain development and sexual differentiation. PMID:19207813

  7. Gustatory perception and fat body energy metabolism are jointly affected by vitellogenin and juvenile hormone in honey bees.

    PubMed

    Wang, Ying; Brent, Colin S; Fennern, Erin; Amdam, Gro V

    2012-06-01

    Honey bees (Apis mellifera) provide a system for studying social and food-related behavior. A caste of workers performs age-related tasks: young bees (nurses) usually feed the brood and other adult bees inside the nest, while older bees (foragers) forage outside for pollen, a protein/lipid source, or nectar, a carbohydrate source. The workers' transition from nursing to foraging and their foraging preferences correlate with differences in gustatory perception, metabolic gene expression, and endocrine physiology including the endocrine factors vitellogenin (Vg) and juvenile hormone (JH). However, the understanding of connections among social behavior, energy metabolism, and endocrine factors is incomplete. We used RNA interference (RNAi) to perturb the gene network of Vg and JH to learn more about these connections through effects on gustation, gene transcripts, and physiology. The RNAi perturbation was achieved by single and double knockdown of the genes ultraspiracle (usp) and vg, which encode a putative JH receptor and Vg, respectively. The double knockdown enhanced gustatory perception and elevated hemolymph glucose, trehalose, and JH. We also observed transcriptional responses in insulin like peptide 1 (ilp1), the adipokinetic hormone receptor (AKHR), and cGMP-dependent protein kinase (PKG, or "foraging gene" Amfor). Our study demonstrates that the Vg-JH regulatory module controls changes in carbohydrate metabolism, but not lipid metabolism, when worker bees shift from nursing to foraging. The module is also placed upstream of ilp1, AKHR, and PKG for the first time. As insulin, adipokinetic hormone (AKH), and PKG pathways influence metabolism and gustation in many animals, we propose that honey bees have conserved pathways in carbohydrate metabolism and conserved connections between energy metabolism and gustatory perception. Thus, perhaps the bee can make general contributions to the understanding of food-related behavior and metabolic disorders.

  8. Gustatory Perception and Fat Body Energy Metabolism Are Jointly Affected by Vitellogenin and Juvenile Hormone in Honey Bees

    PubMed Central

    Wang, Ying; Brent, Colin S.; Fennern, Erin; Amdam, Gro V.

    2012-01-01

    Honey bees (Apis mellifera) provide a system for studying social and food-related behavior. A caste of workers performs age-related tasks: young bees (nurses) usually feed the brood and other adult bees inside the nest, while older bees (foragers) forage outside for pollen, a protein/lipid source, or nectar, a carbohydrate source. The workers' transition from nursing to foraging and their foraging preferences correlate with differences in gustatory perception, metabolic gene expression, and endocrine physiology including the endocrine factors vitellogenin (Vg) and juvenile hormone (JH). However, the understanding of connections among social behavior, energy metabolism, and endocrine factors is incomplete. We used RNA interference (RNAi) to perturb the gene network of Vg and JH to learn more about these connections through effects on gustation, gene transcripts, and physiology. The RNAi perturbation was achieved by single and double knockdown of the genes ultraspiracle (usp) and vg, which encode a putative JH receptor and Vg, respectively. The double knockdown enhanced gustatory perception and elevated hemolymph glucose, trehalose, and JH. We also observed transcriptional responses in insulin like peptide 1 (ilp1), the adipokinetic hormone receptor (AKHR), and cGMP-dependent protein kinase (PKG, or “foraging gene” Amfor). Our study demonstrates that the Vg–JH regulatory module controls changes in carbohydrate metabolism, but not lipid metabolism, when worker bees shift from nursing to foraging. The module is also placed upstream of ilp1, AKHR, and PKG for the first time. As insulin, adipokinetic hormone (AKH), and PKG pathways influence metabolism and gustation in many animals, we propose that honey bees have conserved pathways in carbohydrate metabolism and conserved connections between energy metabolism and gustatory perception. Thus, perhaps the bee can make general contributions to the understanding of food-related behavior and metabolic disorders. PMID

  9. Characterization of an isopentenyl diphosphate isomerase involved in the juvenile hormone pathway in Aedes aegypti.

    PubMed

    Diaz, Miguel E; Mayoral, Jaime G; Priestap, Horacio; Nouzova, Marcela; Rivera-Perez, Crisalejandra; Noriega, Fernando G

    2012-10-01

    Isopentenyl diphosphate isomerase (IPPI) is an enzyme involved in the synthesis of juvenile hormone (JH) in the corpora allata (CA) of insects. IPPI catalyzes the conversion of isopentenyl pyrophosphate (IPP) to dimethylallyl pyrophosphate (DMAPP); afterward IPP and DMAPP condense in a head-to-tail manner to produce geranyl diphosphate (GPP), this head-to-tail condensation can be repeated, by the further reaction of GPP with IPP, yielding the JH precursor farnesyl diphosphate. An IPPI expressed sequence tag (EST) was obtained from an Aedes aegypti corpora-allata + corpora cardiaca library. Its full-length cDNA encodes a 244-aa protein that shows a high degree of similarity with type I IPPIs from other organisms, particularly for those residues that have important roles in catalysis, metal coordination and interaction with the diphosphate moiety of the IPP. Heterologous expression produced a recombinant protein that metabolized IPP into DMAPP; treatment of DMAPP with phosphoric acid produced isoprene, a volatile compound that was measured with an assay based on a solid-phase micro extraction protocol and direct analysis by gas chromatography. A. aegypti IPPI (AaIPPI) required Mg(2+) or Mn(2+) but not Zn(2+) for full activity and it was entirely inhibited by iodoacetamide. Real time PCR experiments showed that AaIPPI is highly expressed in the CA. Changes in AaIPPI mRNA levels in the CA in the pupal and adult female mosquito corresponded well with changes in JH synthesis (Li et al., 2003). This is the first molecular and functional characterization of an isopentenyl diphosphate isomerase involved in the production of juvenile hormone in the CA of an insect.

  10. Genetic differences in the production of male neonates in Daphnia magna exposed to juvenile hormone analogs.

    PubMed

    Oda, Shigeto; Tatarazako, Norihisa; Watanabe, Hajime; Morita, Masatoshi; Iguchi, Taisen

    2006-06-01

    We studied the susceptibility of three genetically different strains of the cyclical parthenogen Daphnia magna (Cladocera, Crustacea) in producing male neonates following exposure to juvenile hormone analogs. In experiment 1, NIES, Clone A, and Belgium A strains were exposed to the insect growth regulators (IGRs) fenoxycarb or epofenonane in a 21-day reproduction experiment. Fenoxycarb exposure decreased the total number of neonates and increased production of male neonates in a concentration-dependent manner in the NIES strain. The decrease in the total number of neonates was so great in Clone A following fenoxycarb exposure that male neonates were not observed, even at the highest concentration, where the total number of neonates was only 2% of the control. In the Belgium A strain, male neonates were observed at a rate of about 20% following exposure to the highest fenoxycarb concentration, but the total number observed was small. Epofenonane did not decrease reproduction in the NIES and Belgium A strains as dramatically as did fenoxycarb, but the neonatal sex ratio changed in a concentration-dependent manner. Although the ratio of males was as low as about 10%, induction of male neonates was also observed in Clone A following epofenonane exposure. In experiment 2, gravid females were exposed to high concentrations (5 or 10 microg/l) of fenoxycarb or pyriproxyfen for 12h. These treatments induced the production of male neonates in all strains, with a small decrease in the total number of neonates. Although induction of male neonates by juvenile hormones and their analogs was universal among genetically different strains, care is needed in interpreting the results of the 21-day reproduction tests, because decreased numbers of neonates at higher concentrations could obscure the presence of male neonates.

  11. Is Juvenile Hormone a potential mechanism that underlay the "branched Y-model"?

    PubMed

    Márquez-García, Armando; Canales-Lazcano, Jorge; Rantala, Markus J; Contreras-Garduño, Jorge

    2016-05-01

    Trade-offs are a central tenet in the life-history evolution and the simplest model to understand it is the "Y" model: the investment of one arm will affect the investment of the other arm. However, this model is by far more complex, and a "branched Y-model" is proposed: trade-offs could exist within each arm of the Y, but the mechanistic link is unknown. Here we used Tenebrio molitor to test if Juvenile Hormone (JH) could be a mechanistic link behind the "branched Y-model". Larvae were assigned to one of the following experimental groups: (1) low, (2) medium and (3) high doses of methoprene (a Juvenile Hormone analogue, JHa), (4) acetone (methoprene diluents; control one) or (5) näive (handled in the same way as other groups; control two). The JHa lengthened the time of development from larvae to pupae and larvae to adults, resulting in adults with a larger size. Males with medium and long JHa treatment doses were favored with female choice, but had smaller testes and fewer viable sperm. There were no differences between groups in regard to the number of spermatozoa of males, or the number of ovarioles or eggs of females. This results suggest that JH: (i) is a mechanistic link of insects "branched Y model", (ii) is a double ended-sword because it may not only provide benefits on reproduction but could also impose costs, and (iii) has a differential effect on each sex, being males more affected than females.

  12. National Implications in Juvenile Justice: The Influence of Juvenile Mentoring Programs on At Risk Youth.

    ERIC Educational Resources Information Center

    Belshaw, Scott H.; Kritsonis, William Allan

    2007-01-01

    In 1972 the federal government created the Juvenile Justice Delinquency Prevention Act that procured funding for various governmental programs to combat the sudden increase in juvenile crime. A provision of this Act set out the creation of mentoring programs to help decrease the juvenile crime rate and dropout rates in secondary schools. This…

  13. Regulatory roles of biogenic amines and juvenile hormone in the reproductive behavior of the western tarnished plant bug (Lygus hesperus).

    PubMed

    Brent, Colin S; Miyasaki, Katelyn; Vuong, Connor; Miranda, Brittany; Steele, Bronwen; Brent, Kristoffer G; Nath, Rachna

    2016-02-01

    Mating induces behavioral and physiological changes in the plant bug Lygus hesperus Knight (Hemiptera: Miridae). After receiving seminal products, which include the systemic regulator juvenile hormone (JH), females enter a post-mating period lasting several days during which they enhance their oviposition rate and lose interest in remating. To elucidate the regulation of these behavioral changes in L. hesperus, biogenic amines were quantified in the heads of females at 5 min, 1 h and 24 h after copulation and compared to levels in virgins using high-performance liquid chromatography coupled with electrochemical detection. Mating significantly increased dopamine (DA) after 1 and 24 h, and decreased octopamine (OA) after 5 min and 1 h. Serotonin did not change with mating, but tyramine was significantly reduced after 5 min. While injection of amines into virgin females did not influence sexual receptivity, OA caused a decrease in oviposition during the 24 h following injection. Topical application of the JH analog methoprene to virgins caused an increase in DA, and a decline in mating propensity, but did not influence other amines or the oviposition rate. The results suggest the decline in OA observed immediately after mating may promote egg laying, and that male-derived JH may induce an increase in DA that could account for the post-mating loss of sexual receptivity.

  14. Argonaute 1 is indispensable for juvenile hormone mediated oogenesis in the migratory locust, Locusta migratoria.

    PubMed

    Song, Jiasheng; Guo, Wei; Jiang, Feng; Kang, Le; Zhou, Shutang

    2013-09-01

    Juvenile hormone (JH) is the primary hormone controlling vitellogenesis and oocyte maturation in the migratory locust Locusta migratoria, an evolutionarily primitive insect species with panoistic ovaries. However, molecular mechanisms of locust oogenesis remain unclear and the role of microRNA (miRNA) in JH mediated locust vitellogenesis and oocyte maturation has not been explored. Using miRNA sequencing and quantification with small RNA libraries derived from fat bodies of JH-deprived versus JH analog-exposed female adult locusts, we have identified 83 JH up-regulated and 60 JH down-regulated miRNAs. QRT-PCR validation has confirmed that transcription of selected miRNAs responded to JH administration and correlated with changes in endogenous hemolymph JH titers. Depletion of Argonaute 1 (Ago1), a key regulator of miRNA biogenesis and function by RNAi in female adult locusts dramatically decreased the expression of vitellogenin (Vg) and severely impaired follicular epithelium development, terminal oocyte maturation and ovarian growth. Our data indicate that Ago1 and Ago1-dependent miRNAs play a crucial role in locust vitellogenesis and egg production.

  15. Juvenile hormone regulation of female reproduction in the common bed bug, Cimex lectularius

    PubMed Central

    Gujar, Hemant; Palli, Subba Reddy

    2016-01-01

    To begin studies on reproduction in common bed bug, Cimex lectularius, we identified three genes coding for vitellogenin (Vg, a protein required for the reproductive success of insects) and studied their hormonal regulation. RNA interference studied showed that expression of Vg3 gene in the adult females is a prerequisite for successful completion of embryogenesis in the eggs laid by them. Juvenile hormone (JH) receptor, Methoprene-tolerant (Met), steroid receptor coactivator (SRC) and GATAa but not ecdysone receptor (EcR) or its partner, ultraspiracle (USP) are required for expression of Vg genes. Feeding and mating working through Vg, Met, SRC, EcR, and GATAa regulate oocyte development. Knockdown of the expression of Met, SRC, EcR, USP, BR-C (Broad-Complex), TOR (target of rapamycin), and GATAa in female adults resulted in a reduction in the number eggs laid by them. Interestingly, Kruppel homolog 1 (Kr-h1) knockdown in the adult females did not reduce their fecundity but affected the development of embryos in the eggs laid by females injected with Kr-h1 double-stranded RNA. These data suggest that JH functioning through Met and SRC regulate both vitellogenesis and oogenesis in C. lectularius. However, JH does not work through Kr-h1 but may work through transcription factors not yet identified. PMID:27762340

  16. Apis mellifera ultraspiracle: cDNA sequence and rapid up-regulation by juvenile hormone.

    PubMed

    Barchuk, A R; Maleszka, R; Simões, Z L P

    2004-10-01

    Two hormones, 20-hydroxyecdysone (20E) and juvenile hormone (JH) are key regulators of insect development including the differentiation of the alternative caste phenotypes of social insects. In addition, JH plays a different role in adult honey bees, acting as a 'behavioural pacemaker'. The functional receptor for 20E is a heterodimer consisting of the ecdysone receptor and ultraspiracle (USP) whereas the identity of the JH receptor remains unknown. We have cloned and sequenced a cDNA encoding Apis mellifera ultraspiracle (AMUSP) and examined its responses to JH. A rapid, but transient up-regulation of the AMUSP messenger is observed in the fat bodies of both queens and workers. AMusp appears to be a single copy gene that produces two transcripts ( approximately 4 and approximately 5 kb) that are differentially expressed in the animal's body. The predicted AMUSP protein shows greater sequence similarity to its orthologues from the vertebrate-crab-tick-locust group than to the dipteran-lepidopteran group. These characteristics and the rapid up-regulation by JH suggest that some of the USP functions in the honey bee may depend on ligand binding.

  17. Juvenile hormone regulation of an insect gene: a specific transcription factor and a DNA response element.

    PubMed

    Zhang, J; Saleh, D S; Wyatt, G R

    1996-08-30

    We have used locust fat body nuclear protein extracts and upstream DNA of the juvenile hormone (JH)-inducible locust gene, jhp21, to examine the regulation of specific transcription by JH. Promoter activity was assayed with G-free cassette reporter constructs. Nuclear extracts from adult female fat body, previously exposed to JH or an analog, actively transcribe from the jhp21 promoter and a control adenovirus major late (AdML) promoter, whereas extracts from JH-deprived female fat body, or other tissues, transcribe strongly from the AdML promoter but weakly or not at all from the jhp21 promoter. Transcription is enhanced by sequences between -140 and -211 nt from the jhp21 transcription start point (tsp), which include a CAAT box, and also by sequences between -1056 and -1200. A 15-nt partially palindromic sequence element found at -1152, resembling known hormone response elements, was shown to stimulate transcription when restored to truncated jhp21 DNA. Two very similar sequences occur further upstream. In electrophoretic mobility shift assays (EMSA), the same sequence element was shown to specifically bind a protein that was present in nuclear extracts from JH-exposed, but not from JH-deprived, fat body. Several lines of evidence suggest that the DNA element may be a JH response element (JHRE). The JH-induced protein that binds to it appears to be a transcription factor that activates the initiation of JH target gene (jhp21) transcription, and could be a JH receptor.

  18. Juvenile hormone regulation of female reproduction in the common bed bug, Cimex lectularius.

    PubMed

    Gujar, Hemant; Palli, Subba Reddy

    2016-10-20

    To begin studies on reproduction in common bed bug, Cimex lectularius, we identified three genes coding for vitellogenin (Vg, a protein required for the reproductive success of insects) and studied their hormonal regulation. RNA interference studied showed that expression of Vg3 gene in the adult females is a prerequisite for successful completion of embryogenesis in the eggs laid by them. Juvenile hormone (JH) receptor, Methoprene-tolerant (Met), steroid receptor coactivator (SRC) and GATAa but not ecdysone receptor (EcR) or its partner, ultraspiracle (USP) are required for expression of Vg genes. Feeding and mating working through Vg, Met, SRC, EcR, and GATAa regulate oocyte development. Knockdown of the expression of Met, SRC, EcR, USP, BR-C (Broad-Complex), TOR (target of rapamycin), and GATAa in female adults resulted in a reduction in the number eggs laid by them. Interestingly, Kruppel homolog 1 (Kr-h1) knockdown in the adult females did not reduce their fecundity but affected the development of embryos in the eggs laid by females injected with Kr-h1 double-stranded RNA. These data suggest that JH functioning through Met and SRC regulate both vitellogenesis and oogenesis in C. lectularius. However, JH does not work through Kr-h1 but may work through transcription factors not yet identified.

  19. Function, diversity, and application of insect juvenile hormone epoxidases (CYP15).

    PubMed

    Daimon, Takaaki; Shinoda, Tetsuro

    2013-01-01

    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. © 2013 International Union of Biochemistry and Molecular Biology, Inc.

  20. Autonomous regulation of the insect gut by circadian genes acting downstream of juvenile hormone signaling

    PubMed Central

    Bajgar, Adam; Jindra, Marek; Dolezel, David

    2013-01-01

    In temperate regions, the shortening day length informs many insect species to prepare for winter by inducing diapause. The adult diapause of the linden bug, Pyrrhocoris apterus, involves a reproductive arrest accompanied by energy storage, reduction of metabolic needs, and preparation to withstand low temperatures. By contrast, nondiapause animals direct nutrient energy to muscle activity and reproduction. The photoperiod-dependent switch from diapause to reproduction is systemically transmitted throughout the organism by juvenile hormone (JH). Here, we show that, at the organ-autonomous level of the insect gut, the decision between reproduction and diapause relies on an interaction between JH signaling and circadian clock genes acting independently of the daily cycle. The JH receptor Methoprene-tolerant and the circadian proteins Clock and Cycle are all required in the gut to activate the Par domain protein 1 gene during reproduction and to simultaneously suppress a mammalian-type cryptochrome 2 gene that promotes the diapause program. A nonperiodic, organ-autonomous feedback between Par domain protein 1 and Cryptochrome 2 then orchestrates expression of downstream genes that mark the diapause vs. reproductive states of the gut. These results show that hormonal signaling through Methoprene-tolerant and circadian proteins controls gut-specific gene activity that is independent of circadian oscillations but differs between reproductive and diapausing animals. PMID:23442387

  1. The mode of action of juvenile hormone and ecdysone: towards an epi-endocrinological paradigm?

    PubMed

    De Loof, Arnold; Boerjan, Bart; Ernst, Ulrich R; Schoofs, Liliane

    2013-07-01

    In some insect species, two sites of juvenile hormone (JH) synthesis have been reported: the very well documented corpora allata that secrete JH for "general use", and the reproductive system, in particular the male accessory glands, in which the function of the sometimes huge amounts of JH (e.g. in Hyalophora cecropia) remains to be clarified. A recent finding in Schistocerca gregaria, namely that suppression of the ecdysteroid peak preceding a molt by RNAi of the Halloween genes spook, phantom and shade does not impede normal molting, challenges the (never experimentally proven) classical concept that such a peak is causally linked to a molt. Recent developments in epigenetic control of gene expression in both the honey bee and in locusts suggest that, in addition to the classical scheme of hormone-receptor (membrane- and/or nuclear) mode of action, there may be a third way. Upon combining these and other orphan data that do not fit in the commonly accepted textbook schemes, we here advance the working hypothesis that both JH and ecdysone might be important but overlooked players in epigenetic control of gene expression, in particular at extreme concentrations (peak values or total absence). In this review, we put forward how epi-endocrinology can complement classical arthropod endocrinology. Copyright © 2013 Elsevier Inc. All rights reserved.

  2. Evolution of Ecdysis and Metamorphosis in Arthropods: The Rise of Regulation of Juvenile Hormone.

    PubMed

    Cheong, Sam P S; Huang, Juan; Bendena, William G; Tobe, Stephen S; Hui, Jerome H L

    2015-11-01

    Arthropods are the most successful group of animals, and are found in diverse habitats; they account for more than 80% of described animal species. A rigid exoskeleton is a common feature that is shared across the different groups of arthropods. The exoskeleton offers protection and is shed between developmental stages via a unique evolutionarily conserved process known as molting/ecdysis. Molting is triggered by steroid hormones, the ecdysteroids, and the regulation of their biosynthesis has long been proposed as a contributor to the success of arthropods during evolution. Nevertheless, how novelties arose that contributed to the diversifications of arthropods remain unclear. Juvenile hormones (JHs) are sequiterpenoids that were thought to be unique to insects, modulating the timing of metamorphosis in conjunction with the actions of ecdysteroids. Here, we revisit the old question of "the role that the sesquiterpenoids play in arthropod evolution" with a focus on the neglected non-insect arthropods. We hypothesize that the sesquiterpenoid, methyl farnesoate (MF), had already established regulatory functions in the last common ancestor of arthropods, and the difference in the regulation of biosynthesis and degradation of sesquiterpenoids, such as MF and JH, was another major driving force in the successful radiation of insects.

  3. Choristoneura fumiferana entomopoxvirus prevents metamorphosis and modulates juvenile hormone and ecdysteroid titers.

    PubMed

    Palli, S R; Ladd, T R; Tomkins, W L; Shu, S; Ramaswamy, S B; Tanaka, Y; Arif, B; Retnakaran, A

    2000-01-01

    Larvae of the spruce budworm, Choristoneura fumiferana, infected with C. fumiferana entomopoxvirus (CfEPV) continue to feed and grow without undergoing metamorphosis and die as moribund larvae. The lethal dose (LD(50)) and lethal time (LT(50)) values for fourth instar larvae are 2.4 spheroids and 25.2 days, respectively. One hundred percent of the control fourth instar larvae, which were fed water instead of virus, pupated by 18 days post feeding (PF). Only 30% of the larvae that were fed the LD(50) dose and none of the larvae that were fed the LD(95) dose pupated by 18 days PF. Of the control larvae, 95% became adults by 24 days PF, whereas in the treated group only 2% of larvae that were fed the LD(50) dose and none of the larvae that were fed the LD(95) dose became adults by 24 days PF. Some of the virus-treated larvae died as either larval/pupal or pupal/adult intermediates. These phenotypic effects were similar to the larval/pupal and pupal/adult intermediates, resulting from treating larvae with juvenile hormone (JH) or its analogs, which suggests that EPV may cause such abnormalities by modulating JH and/or ecdysteroid titers. In untreated sixth instar larvae the JH titer decreased to low levels by 24 h after ecdysis and remained low throughout larval life. EPV-fed sixth instar larvae had 2112 pg/ml on day 0, 477 pg/ml on day 1 and 875 pg/ml on day 8 of the sixth instar. Control larvae contained 860 ng of ecdysteroids per ml hemolymph on day 8 of the sixth instar, whereas EPV-treated larvae of the same age (30 days PF) had only 107 ng of ecdysteroids per ml of hemolymph. Thus, EPV infection results in increased JH titer and decreased ecdysteroid titer. Northern hybridization analysis was performed using RNA isolated from control and EPV-fed larvae and cDNA probes for (i) juvenile hormone esterase (JHE), which is JH inducible, (ii) Choristoneura hormone receptor 3 (CHR3), which is ecdysteroid inducible, and (iii) larval specific diapause associated protein 1

  4. Precocious metamorphosis in the juvenile hormone-deficient mutant of the silkworm, Bombyx mori.

    PubMed

    Daimon, Takaaki; Kozaki, Toshinori; Niwa, Ryusuke; Kobayashi, Isao; Furuta, Kenjiro; Namiki, Toshiki; Uchino, Keiro; Banno, Yutaka; Katsuma, Susumu; Tamura, Toshiki; Mita, Kazuei; Sezutsu, Hideki; Nakayama, Masayoshi; Itoyama, Kyo; Shimada, Toru; Shinoda, Tetsuro

    2012-01-01

    Insect molting and metamorphosis are intricately governed by two hormones, ecdysteroids and juvenile hormones (JHs). JHs prevent precocious metamorphosis and allow the larva to undergo multiple rounds of molting until it attains the proper size for metamorphosis. In the silkworm, Bombyx mori, several "moltinism" mutations have been identified that exhibit variations in the number of larval molts; however, none of them have been characterized molecularly. Here we report the identification and characterization of the gene responsible for the dimolting (mod) mutant that undergoes precocious metamorphosis with fewer larval-larval molts. We show that the mod mutation results in complete loss of JHs in the larval hemolymph and that the mutant phenotype can be rescued by topical application of a JH analog. We performed positional cloning of mod and found a null mutation in the cytochrome P450 gene CYP15C1 in the mod allele. We also demonstrated that CYP15C1 is specifically expressed in the corpus allatum, an endocrine organ that synthesizes and secretes JHs. Furthermore, a biochemical experiment showed that CYP15C1 epoxidizes farnesoic acid to JH acid in a highly stereospecific manner. Precocious metamorphosis of mod larvae was rescued when the wild-type allele of CYP15C1 was expressed in transgenic mod larvae using the GAL4/UAS system. Our data therefore reveal that CYP15C1 is the gene responsible for the mod mutation and is essential for JH biosynthesis. Remarkably, precocious larval-pupal transition in mod larvae does not occur in the first or second instar, suggesting that authentic epoxidized JHs are not essential in very young larvae of B. mori. Our identification of a JH-deficient mutant in this model insect will lead to a greater understanding of the molecular basis of the hormonal control of development and metamorphosis.

  5. Molecular Determinants of Juvenile Hormone Action as Revealed by 3D QSAR Analysis in Drosophila

    PubMed Central

    Beňo, Milan; Farkaš, Robert

    2009-01-01

    Background Postembryonic development, including metamorphosis, of many animals is under control of hormones. In Drosophila and other insects these developmental transitions are regulated by the coordinate action of two principal hormones, the steroid ecdysone and the sesquiterpenoid juvenile hormone (JH). While the mode of ecdysone action is relatively well understood, the molecular mode of JH action remains elusive. Methodology/Principal Findings To gain more insights into the molecular mechanism of JH action, we have tested the biological activity of 86 structurally diverse JH agonists in Drosophila melanogaster. The results were evaluated using 3D QSAR analyses involving CoMFA and CoMSIA procedures. Using this approach we have generated both computer-aided and species-specific pharmacophore fingerprints of JH and its agonists, which revealed that the most active compounds must possess an electronegative atom (oxygen or nitrogen) at both ends of the molecule. When either of these electronegative atoms are replaced by carbon or the distance between them is shorter than 11.5 Å or longer than 13.5 Å, their biological activity is dramatically decreased. The presence of an electron-deficient moiety in the middle of the JH agonist is also essential for high activity. Conclusions/Significance The information from 3D QSAR provides guidelines and mechanistic scope for identification of steric and electrostatic properties as well as donor and acceptor hydrogen-bonding that are important features of the ligand-binding cavity of a JH target protein. In order to refine the pharmacophore analysis and evaluate the outcomes of the CoMFA and CoMSIA study we used pseudoreceptor modeling software PrGen to generate a putative binding site surrogate that is composed of eight amino acid residues corresponding to the defined molecular interactions. PMID:19547707

  6. Multiple exportins influence thyroid hormone receptor localization

    PubMed Central

    Subramanian, Kelly S.; Dziedzic, Rose C.; Nelson, Hallie N.; Stern, Mary E.; Roggero, Vincent R.; Bondzi, Cornelius; Allison, Lizabeth A.

    2015-01-01

    The thyroid hormone receptor (TR) undergoes nucleocytoplasmic shuttling and regulates target genes involved in metabolism and development. Previously, we showed that TR follows a CRM1/calreticulin-mediated nuclear export pathway. However, two lines of evidence suggest TR also follows another pathway: export is only partially blocked by leptomycin B (LMB), a CRM1-specific inhibitor; and we identified nuclear export signals in TR that are LMB-resistant. To determine whether other exportins are involved in TR shuttling, we used RNA interference and fluorescence recovery after photobleaching shuttling assays in transfected cells. Knockdown of exportins 4, 5, and 7 altered TR shuttling dynamics, and when exportins 5 and 7 were overexpressed, TR distribution shifted towards the cytosol. To further assess the effects of exportin overexpression, we examined transactivation of a TR-responsive reporter gene. Our data indicate that multiple exportins influence TR localization, highlighting a fine balance of nuclear import, retention, and export that modulates TR function. PMID:25911113

  7. Multiple exportins influence thyroid hormone receptor localization.

    PubMed

    Subramanian, Kelly S; Dziedzic, Rose C; Nelson, Hallie N; Stern, Mary E; Roggero, Vincent R; Bondzi, Cornelius; Allison, Lizabeth A

    2015-08-15

    The thyroid hormone receptor (TR) undergoes nucleocytoplasmic shuttling and regulates target genes involved in metabolism and development. Previously, we showed that TR follows a CRM1/calreticulin-mediated nuclear export pathway. However, two lines of evidence suggest TR also follows another pathway: export is only partially blocked by leptomycin B (LMB), a CRM1-specific inhibitor; and we identified nuclear export signals in TR that are LMB-resistant. To determine whether other exportins are involved in TR shuttling, we used RNA interference and fluorescence recovery after photobleaching shuttling assays in transfected cells. Knockdown of exportins 4, 5, and 7 altered TR shuttling dynamics, and when exportins 5 and 7 were overexpressed, TR distribution shifted toward the cytosol. To further assess the effects of exportin overexpression, we examined transactivation of a TR-responsive reporter gene. Our data indicate that multiple exportins influence TR localization, highlighting a fine balance of nuclear import, retention, and export that modulates TR function.

  8. Common and distinct roles of juvenile hormone signaling genes in metamorphosis of holometabolous and hemimetabolous insects.

    PubMed

    Konopova, Barbora; Smykal, Vlastimil; Jindra, Marek

    2011-01-01

    Insect larvae metamorphose to winged and reproductive adults either directly (hemimetaboly) or through an intermediary pupal stage (holometaboly). In either case juvenile hormone (JH) prevents metamorphosis until a larva has attained an appropriate phase of development. In holometabolous insects, JH acts through its putative receptor Methoprene-tolerant (Met) to regulate Krüppel-homolog 1 (Kr-h1) and Broad-Complex (BR-C) genes. While Met and Kr-h1 prevent precocious metamorphosis in pre-final larval instars, BR-C specifies the pupal stage. How JH signaling operates in hemimetabolous insects is poorly understood. Here, we compare the function of Met, Kr-h1 and BR-C genes in the two types of insects. Using systemic RNAi in the hemimetabolous true bug, Pyrrhocoris apterus, we show that Met conveys the JH signal to prevent premature metamorphosis by maintaining high expression of Kr-h1. Knockdown of either Met or Kr-h1 (but not of BR-C) in penultimate-instar Pyrrhocoris larvae causes precocious development of adult color pattern, wings and genitalia. A natural fall of Kr-h1 expression in the last larval instar normally permits adult development, and treatment with an exogenous JH mimic methoprene at this time requires both Met and Kr-h1 to block the adult program and induce an extra larval instar. Met and Kr-h1 therefore serve as JH-dependent repressors of deleterious precocious metamorphic changes in both hemimetabolous and holometabolous juveniles, whereas BR-C has been recruited for a new role in specifying the holometabolous pupa. These results show that despite considerable evolutionary distance, insects with diverse developmental strategies employ a common-core JH signaling pathway to commit to adult morphogenesis.

  9. Common and Distinct Roles of Juvenile Hormone Signaling Genes in Metamorphosis of Holometabolous and Hemimetabolous Insects

    PubMed Central

    Jindra, Marek

    2011-01-01

    Insect larvae metamorphose to winged and reproductive adults either directly (hemimetaboly) or through an intermediary pupal stage (holometaboly). In either case juvenile hormone (JH) prevents metamorphosis until a larva has attained an appropriate phase of development. In holometabolous insects, JH acts through its putative receptor Methoprene-tolerant (Met) to regulate Krüppel-homolog 1 (Kr-h1) and Broad-Complex (BR-C) genes. While Met and Kr-h1 prevent precocious metamorphosis in pre-final larval instars, BR-C specifies the pupal stage. How JH signaling operates in hemimetabolous insects is poorly understood. Here, we compare the function of Met, Kr-h1 and BR-C genes in the two types of insects. Using systemic RNAi in the hemimetabolous true bug, Pyrrhocoris apterus, we show that Met conveys the JH signal to prevent premature metamorphosis by maintaining high expression of Kr-h1. Knockdown of either Met or Kr-h1 (but not of BR-C) in penultimate-instar Pyrrhocoris larvae causes precocious development of adult color pattern, wings and genitalia. A natural fall of Kr-h1 expression in the last larval instar normally permits adult development, and treatment with an exogenous JH mimic methoprene at this time requires both Met and Kr-h1 to block the adult program and induce an extra larval instar. Met and Kr-h1 therefore serve as JH-dependent repressors of deleterious precocious metamorphic changes in both hemimetabolous and holometabolous juveniles, whereas BR-C has been recruited for a new role in specifying the holometabolous pupa. These results show that despite considerable evolutionary distance, insects with diverse developmental strategies employ a common-core JH signaling pathway to commit to adult morphogenesis. PMID:22174880

  10. Fast induction of vitellogenin gene expression by juvenile hormone III in the cockroach Blattella germanica (L.) (Dictyoptera, Blattellidae).

    PubMed

    Comas, D; Piulachs, M D; Bellés, X

    1999-09-01

    The present paper describes the effect of juvenile hormone III (JH III) upon vitellogenin (Vg) gene expression in cardioallatectomized females of Blattella germanica. Northern blot analyses of time course studies showed that Vg mRNA can be detected 2 h after the treatment with 1 microgram of JH III. Western blot analyses revealed that Vg protein is detectable 4 h after the same treatment. The study of the influence of the age showed that 48-h-old females seem more sensitive than 24-h-old females, whereas differences were less apparent between 48- and 72-h-old females. Dose-response studies indicated that 0.01 microgram of JH III is ineffective, whereas the doses of 0.1, 1 and 10 micrograms induced the synthesis of Vg in a dose-dependent fashion. Finally, the administration of three successive doses, of 0.01 microgram of JH III each, did not result in detectable Vg production, whereas two doses of 0.01 microgram followed by one of 1 microgram of JH III induced a greater response than that resulting from a sole dose of 1 microgram of JH III, which suggests that sub-effective doses of JH III elicit a priming effect on Vg production.

  11. Metabolic analysis reveals changes in the mevalonate and juvenile hormone synthesis pathways linked to the mosquito reproductive physiology.

    PubMed

    Rivera-Perez, Crisalejandra; Nouzova, Marcela; Lamboglia, Ivanna; Noriega, Fernando G

    2014-08-01

    Juvenile hormone (JH) regulates reproductive maturation in insects; therefore interruption of JH biosynthesis has been considered as a strategy for the development of target-specific insecticides. The corpora allata (CA) from mosquitoes is highly specialized to supply variable levels of JH, which are linked to ovarian developmental stages and influenced by nutritional signals. However, very little is known about how changes in JH synthesis relate to reproductive physiology and how JH synthesis regulation is translated into changes in the CA machinery. With the advent of new methods that facilitate the analysis of transcripts, enzymes and metabolites in the minuscule CA, we were able to provide comprehensive descriptions of the mevalonic (MVA) and JH synthesis pathways by integrating information on changes in the basic components of those pathways. Our results revealed remarkable dynamic changes in JH synthesis and exposed part of a complex mechanism that regulates CA activity. Principal component (PC) analyses validated that both pathways (MVAP and JH-branch) are transcriptionally co-regulated as a single unit, and catalytic activities for the enzymes of the MVAP and JH-branch also changed in a coordinate fashion. Metabolite studies showed that global fluctuations in the intermediate pool sizes in the MVAP and JH-branch were often inversely related. PC analyses suggest that in female mosquitoes, there are at least 4 developmental switches that alter JH synthesis by modulating the flux at distinctive points in both pathways.

  12. Juvenile hormone, but not nutrition or social cues, affects reproductive maturation in solitary alkali bees (Nomia melanderi).

    PubMed

    Kapheim, Karen M; Johnson, Makenna M

    2017-08-18

    Eusocial insect colonies are defined by extreme variation in reproductive activity among castes, but the ancestral conditions from which this variation arose are unknown. Investigating the factors that contribute to variation in reproductive physiology among solitary insects that are closely related to social species can help to fill this gap. We experimentally tested the role of nutrition, juvenile hormone, and social cues on reproductive maturation in solitary alkali bees (Halictidae: Nomia melanderi). We find that alkali bee females emerge from overwintering with small Dufour's glands and small ovaries, containing oocytes in the early stages of development. Oocyte maturation occurs rapidly, and is staggered between the two ovaries. Lab-reared females reached reproductive maturity without access to mates or nesting opportunities, and many had resorbed oocytes. Initial activation of these reproductive structures does not depend on pollen consumption, though dietary protein or lipids may be necessary for long-term reproductive activity. JH is likely to be a limiting factor in alkali bee reproductive activation, as females treated with JH were more likely to develop mature oocytes and Dufour's glands. Unlike for related social bees, the effects of JH were not suppressed by the presence of older, reproductive females. These results provide important insight into the factors that influence reproductive activity in an important native pollinator, and those that may have been particularly important in the evolution of reproductive castes. © 2017. Published by The Company of Biologists Ltd.

  13. The roles of juvenile hormone, insulin/target of rapamycin, and ecydsone signaling in regulating body size in Drosophila

    PubMed Central

    Mirth, Christen Kerry; Shingleton, Alexander William

    2014-01-01

    Understanding how organisms regulate their body size has interested biologists for decades. Recent work has shown that both insulin/target of rapamycin (TOR) signaling and the steroid hormone ecdysone act to regulate rates of growth and the duration of the growth period in the fruit fly, Drosophila melanogaster. Our recent work has uncovered a third level of interaction, whereby juvenile hormone (JH) regulates levels of both ecdysone and insulin/TOR signaling to control growth rates. These studies highlight a complex network of interactions involved in regulating body and organ size. PMID:26842847

  14. Sex-steroid and thyroid hormone concentrations in juvenile alligators (Alligator mississippiensis) from contaminated and reference lakes in Florida, USA

    USGS Publications Warehouse

    Grain, D.A.; Guillette, L.J.; Pickford, D.B.; Percival, H.F.; Woodward, A.R.

    1998-01-01

    Sex-steroid and thyroid hormones are critical regulators of growth and reproduction in all vertebrates, and several recent studies suggest that environmental chemicals can alter circulating concentrations of these hormones. This study examines plasma concentrations of estradiol-171?? (E2), testosterone (T), triiodothyronine (T3), and thyroxine (T4) in juvenile alligators (60-140 cm total length) from two contaminated lakes and one reference lake in Florida. First, the data were analyzed by comparing hormone concentrations among males and females from the different lakes. Whereas there were no differences in plasma E2 concentrations among animals of the three lakes, male alligators from the contaminated lakes (Lake Apopka and Lake Okeechobee) had significantly lower plasma T concentrations compared 10 males from the reference take (Lake Woodruff). Concentrations of thyroid hormones also differed in animals of the three lakes, with T4 concentrations being elevated in Lake Okeechobee males compared to Lake Woodruff males. Second, the relationship between body size and hormone concentration was examined using regression analysis. Most notably for steroid hormones, no clear relationship was detected between E2 and total length in Apopka females (r2 0.09, p = 0.54) or between T and total length in Apopka males (r2 = 0.007, p = 0.75). Females from Apopka (r2 = 0.318, p = 0.09) and Okeechobee (r2 = 0.222, p = 0.09) exhibited weak correlations between T3 and total length. Males from Apopka (r2 = 0.015, p = 0.66) and Okeechobee (r2 = 0.128, p = 0.19) showed no correlation between T4 and total length. These results indicate: some of the previously reported abnormalities in steroid hormones of hatchling alligators persist, at least, through the juvenile years; steroid and thyroid hormones are related to body size in juvenile alligators from the reference lake, whereas alligators living in lakes Apopka and Okeechobee experience alterations in circulating thyroid and steroid

  15. Roles of ecdysteroid and juvenile hormone in vitellogenesis in an endoparasitic wasp, Pteromalus puparum (Hymenoptera: Pteromalidae).

    PubMed

    Dong, Sheng-zhang; Ye, Gong-yin; Guo, Jian-yang; Hu, Cui

    2009-01-01

    To elucidate the endocrine regulation of vitellogenesis in an endoparastic wasp (Pteromalus puparum), the titers of ecdysteroid and juvenile hormone (JH) from the whole bodies are measured using the method of radioimmunoassay and GC-MS, and compared with the levels of vitellogenin (Vg) mRNA in the fat bodies, hemolymph Vg and ovarian vitellin (Vt), respectively. The results show that the ecdysteroid titer and fat body Vg mRNA level have a similar dynamics tendency, and the peak titer is at adult eclosion. The titer of JH III and ovarian Vt also have a similar dynamics tendency, and the peak titer is at 48h after eclosion. The profiles of hemolymph Vg, Vg mRNA in fat bodies and ovarian Vt, are also measured in the wasps after treated with different amounts of 20-hydroxyecdysone (20HE) or JH III in female pupa and adults. The results show that 20HE stimulates Vg synthesis in the fat bodies and its release into the hemolymph, and that JH III only accelerates Vg sequestration in the oocytes. Decapitation, which is believed to terminate synthesis of JH in insects, can not inhibit vitellogenesis and oocyte maturation in P. puparum. Furthermore, Vg gene is expressed with a lower titer of JH and depressed by a higher titer of JH III. These studies suggest that ecdysteroids play a role in Vg synthesis and believed to be the dominant hormones in regulation of vitellogenesis in P. puparum, and JHs are not the essential factors to female reproduction in this wasp.

  16. Hormone profile in juvenile systemic lupus erythematosus with previous or current amenorrhea.

    PubMed

    Silva, Clovis A; Deen, Maria E J; Febrônio, Marilia V; Oliveira, Sheila K; Terreri, Maria T; Sacchetti, Silvana B; Sztajnbok, Flavio R; Marini, Roberto; Quintero, Maria V; Bica, Blanca E; Pereira, Rosa M; Bonfá, Eloisa; Ferriani, Virginia P; Robazzi, Teresa C; Magalhães, Claudia S; Hilário, Maria O

    2011-08-01

    To identify the underlying mechanism of amenorrhea in juvenile systemic lupus erythematosus (JSLE) patients, thirty-five (11.7%) JSLE patients with current or previous amenorrhea were consecutively selected among the 298 post-menarche patients followed in 12 Brazilian pediatric rheumatology centers. Pituitary gonadotrophins [follicle-stimulating hormone (FSH) and luteinizing hormone (LH)] and estradiol were evaluated in 32/35 patients, and prolactin and total testosterone in 29/35 patients. Patient's medical records were carefully reviewed according to demographic, clinical and therapeutic findings. The mean duration of amenorrhea was 7.2 ± 3.6 months. Low FSH or LH was observed in 7/32 (22%) JSLE patients and normal FSH or LH in 25 (78%). Remarkably, low levels of FSH or LH were associated with higher frequency of current amenorrhea (57% vs. 0%, P = 0.001), higher median disease activity (SLEDAI) and damage (SLICC/ACR-DI) (18 vs. 4, P = 0.011; 2 vs. 0, P = 0.037, respectively) and higher median current dose of prednisone (60 vs. 10 mg/day, P = 0.0001) compared to normal FSH or LH JSLE patients. None of them had decreased ovarian reserve and premature ovarian failure. Six of 29 (21%) patients had high levels of prolactin, and none had current amenorrhea. No correlations were observed between levels of prolactin and SLEDAI, and levels of prolactin and SLICC/ACR-DI scores (Spearman's coefficient). We have identified that amenorrhea in JSLE is associated with high dose of corticosteroids indicated for active disease due to hypothalamic-pituitary-ovary axis suppression.

  17. Microarray Analysis of Juvenile Hormone Response in Drosophila melanogaster S2 cells

    PubMed Central

    Willis, David K.; Wang, Jun; Lindholm, Joliene R.; Orth, Anthony; Goodman, Walter G.

    2010-01-01

    A microchip array encompassing probes for 14,010 genes of Drosophila melanogaster was used to analyze the effect of juvenile hormone (JH) on genome-wide gene expression. JH is a member of a group of insect hormones involved in regulating larval development and adult reproductive processes. Total RNA was isolated from Drosophila S2 cells after 4 hours treatment with 250 ng/ml (10R) JH III or 250 ng/ml methyl linoleate. A collection of 32 known or putative genes demonstrated a significant change with JH III treatment (r > 2.0, P ≤ 0.005). Of these, the abundance of 13 transcripts was significantly increased and 19 decreased. The expression of a subset of these loci was analyzed by real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR). Three loci that exhibited constant expression in the presence and absence of JH III (RP49 [FBgn0002626], FBgn0023529, and FBgn0034354) were evaluated and found to be reliable invariant reference transcripts for real-time RT-qPCR analysis using BestKeeper and geNorm software. Increased expression in presence of JH III was confirmed by real-time RTqPCR analysis. However, only one of five loci that exhibited reduced expression on microarrays could be confirmed as significantly reduced (P ≤ 0.05). Among the confirmed JH III up-regulated genes were two loci of unknown function (FBgn0040887 and FBgn0037057) and Epac, an exchange protein directly activated by cyclic AMP, a guanine nucleotide exchange factor for Rap1 small GTPase. PMID:20672983

  18. Effects of juvenile hormone and ecdysone on the timing of vitellogenin appearance in hemolymph of queen and worker pupae of Apis mellifera

    PubMed Central

    Barchuk, Angel Roberto; Bitondi, Marcia Maria Gentile; Simões, Zilá Luz Paulino

    2002-01-01

    The caste-specific regulation of vitellogenin synthesis in the honeybee represents a problem with many yet unresolved details. We carried out experiments to determine when levels of vitellogenin are first detected in hemolymph of female castes of Apis mellifera, and whether juvenile hormone and ecdysteroids modulate this process. Vitellogenin levels were measured in hemolymph using immunological techniques. We show that in both castes the appearance of vitellogenin in the hemolymph occurs during the pupal period, but the timing was different in the queen and worker. Vitellogenin appears in queens during an early phase of cuticle pigmentation approximately 60h before eclosion, while in workers the appearance of vitellogenin is more delayed, initiating in the pharate adult stage, approximately 10h before eclosion. The timing of vitellogenin appearance in both castes coincides with a slight increase in endogenous levels of juvenile hormone that occurs at the end of pupal development. The correlation between these events was corroborated by topical application of juvenile hormone. Exogenous juvenile hormone advanced the timing of vitellogenin appearance in both castes, but caste-specific differences in timing were maintained. Injection of actinomycin D prevented the response to juvenile hormone. In contrast, queen and worker pupae that were treated with ecdysone showed a delay in the appearance of vitellogenin. These data suggest that queens and workers share a common control mechanism for the timing of vitellogenin synthesis, involving an increase in juvenile hormone titers in the presence of low levels of ecdysteroids. PMID:15455035

  19. Juvenile hormone biosynthesis in adult Blattella germanica requires nuclear receptors Seven-up and FTZ-F1

    PubMed Central

    Borras-Castells, Ferran; Nieva, Claudia; Maestro, José L.; Maestro, Oscar; Belles, Xavier; Martín, David

    2017-01-01

    In insects, the transition from juvenile development to the adult stage is controlled by juvenile hormone (JH) synthesized from the corpora allata (CA) glands. Whereas a JH-free period during the last juvenile instar triggers metamorphosis and the end of the growth period, the reappearance of this hormone after the imaginal molt marks the onset of reproductive adulthood. Despite the importance of such transition, the regulatory mechanism that controls it remains mostly unknown. Here, using the hemimetabolous insect Blattella germanica, we show that nuclear hormone receptors Seven-up-B (BgSvp-B) and Fushi tarazu-factor 1 (BgFTZ-F1) have essential roles in the tissue- and stage-specific activation of adult CA JH-biosynthetic activity. Both factors are highly expressed in adult CA cells. Moreover, RNAi-knockdown of either BgSvp-B or BgFTZ-F1 results in adult animals with a complete block in two critical JH-dependent reproductive processes, vitellogenesis and oogenesis. We show that this reproductive blockage is the result of a dramatic impairment of JH biosynthesis, due to the CA-specific reduction in the expression of two key JH biosynthetic enzymes, 3-hydroxy-3-methylglutaryl coenzyme A synthase-1 (BgHMG-S1) and HMG-reductase (BgHMG-R). Our findings provide insights into the regulatory mechanisms underlying the specific changes in the CA gland necessary for the proper transition to adulthood. PMID:28074850

  20. Juvenile hormone biosynthesis in adult Blattella germanica requires nuclear receptors Seven-up and FTZ-F1.

    PubMed

    Borras-Castells, Ferran; Nieva, Claudia; Maestro, José L; Maestro, Oscar; Belles, Xavier; Martín, David

    2017-01-11

    In insects, the transition from juvenile development to the adult stage is controlled by juvenile hormone (JH) synthesized from the corpora allata (CA) glands. Whereas a JH-free period during the last juvenile instar triggers metamorphosis and the end of the growth period, the reappearance of this hormone after the imaginal molt marks the onset of reproductive adulthood. Despite the importance of such transition, the regulatory mechanism that controls it remains mostly unknown. Here, using the hemimetabolous insect Blattella germanica, we show that nuclear hormone receptors Seven-up-B (BgSvp-B) and Fushi tarazu-factor 1 (BgFTZ-F1) have essential roles in the tissue- and stage-specific activation of adult CA JH-biosynthetic activity. Both factors are highly expressed in adult CA cells. Moreover, RNAi-knockdown of either BgSvp-B or BgFTZ-F1 results in adult animals with a complete block in two critical JH-dependent reproductive processes, vitellogenesis and oogenesis. We show that this reproductive blockage is the result of a dramatic impairment of JH biosynthesis, due to the CA-specific reduction in the expression of two key JH biosynthetic enzymes, 3-hydroxy-3-methylglutaryl coenzyme A synthase-1 (BgHMG-S1) and HMG-reductase (BgHMG-R). Our findings provide insights into the regulatory mechanisms underlying the specific changes in the CA gland necessary for the proper transition to adulthood.

  1. E-cadherin roles in animal biology: A perspective on thyroid hormone-influence.

    PubMed

    Izaguirre, María Fernanda; Casco, Victor Hugo

    2016-11-04

    The establishment, remodeling and maintenance of tissular architecture during animal development, and even across juvenile to adult life, are deeply regulated by a delicate interplay of extracellular signals, cell membrane receptors and intracellular signal messengers. It is well known that cell adhesion molecules (cell-cell and cell-extracellular matrix) play a critical role in these processes. Particularly, adherens junctions (AJs) mediated by E-cadherin and catenins determine cell-cell contact survival and epithelia function. Consequently, this review seeks to encompass the complex and prolific knowledge about E-cadherin roles during physiological and pathological states, particularly focusing on the influence exerted by the thyroid hormone (TH).

  2. Galanin synaptic input to gonadotropin-releasing hormone perikarya in juvenile and adult female mice: implications for sexual maturity.

    PubMed

    Rajendren, G; Li, X

    2001-11-26

    Changes in connectivity of the gonadotropin-releasing hormone (GnRH) neuronal system are believed to occur during the transition from juvenile to adulthood in females. Experiments were designed to investigate whether there is any difference in the number of galanin inputs to GnRH cells located in the organum vasculosum of lamina terminalis-rostral preoptic area (OVLT-rPOA) between juvenile (2 weeks old) and adult (10 weeks old) female mice. Triple label immunofluorescence staining of brain sections for galanin, GnRH and the presynaptic vesicle marker synaptophysin coupled with confocal microscopy was employed to identify galanin synapses to GnRH perikarya. The number of galanin synapses to GnRH cells and the proportion of GnRH cells with galanin input were significantly higher in adults than in juvenile mice. In adult mice, the proportions of GnRH cells with 0, 1, 2, 3, 4, 5 or 6 galanin synapses/cell were comparable to each other whereas in the juveniles the vast majority of them received no galanin synaptic input. A greater number of galanin synapses in adult as compared with juvenile female mice suggests a functional role for galanin in the maturation of the GnRH system.

  3. Identification of plant compounds that disrupt the insect juvenile hormone receptor complex

    PubMed Central

    Lee, Seok-Hee; Oh, Hyun-Woo; Fang, Ying; An, Saes-Byeol; Park, Doo-Sang; Song, Hyuk-Hwan; Oh, Sei-Ryang; Kim, Soo-Young; Kim, Seonghyun; Kim, Namjung; Raikhel, Alexander S.; Je, Yeon Ho; Shin, Sang Woon

    2015-01-01

    Insects impact human health through vector-borne diseases and cause major economic losses by damaging crops and stored agricultural products. Insect-specific growth regulators represent attractive control agents because of their safety to the environment and humans. We identified plant compounds that serve as juvenile hormone antagonists (PJHANs). Using the yeast two-hybrid system transformed with the mosquito JH receptor as a reporter system, we demonstrate that PJHANs affect the JH receptor, methoprene-tolerant (Met), by disrupting its complex with CYCLE or FISC, formation of which is required for mediating JH action. We isolated five diterpene secondary metabolites with JH antagonist activity from two plants: Lindera erythrocarpa and Solidago serotina. They are effective in causing mortality of mosquito larvae at relatively low LD50 values. Topical application of two diterpenes caused reduction in the expression of Met target genes and retardation of follicle development in mosquito ovaries. Hence, the newly discovered PJHANs may lead to development of a new class of safe and effective pesticides. PMID:25624480

  4. Homeodomain Protein Scr Regulates the Transcription of Genes Involved in Juvenile Hormone Biosynthesis in the Silkworm

    PubMed Central

    Meng, Meng; Liu, Chun; Peng, Jian; Qian, Wenliang; Qian, Heying; Tian, Ling; Li, Jiarui; Dai, Dandan; Xu, Anying; Li, Sheng; Xia, Qingyou; Cheng, Daojun

    2015-01-01

    The silkworm Dominant trimolting (Moltinism, M3) mutant undergoes three larval molts and exhibits precocious metamorphosis. In this study, we found that compared with the wild-type (WT) that undergoes four larval molts, both the juvenile hormone (JH) concentration and the expression of the JH-responsive gene Krüppel homolog 1 (Kr-h1) began to be greater in the second instar of the M3 mutant. A positional cloning analysis revealed that only the homeodomain transcription factor gene Sex combs reduced (Scr) is located in the genomic region that is tightly linked to the M3 locus. The expression level of the Scr gene in the brain-corpora cardiaca-corpora allata (Br-CC-CA) complex, which controls the synthesis of JH, was very low in the final larval instar of both the M3 and WT larvae, and exhibited a positive correlation with JH titer changes. Importantly, luciferase reporter analysis and electrophoretic mobility shift assay (EMSA) demonstrated that the Scr protein could promote the transcription of genes involved in JH biosynthesis by directly binding to the cis-regulatory elements (CREs) of homeodomain protein on their promoters. These results conclude that the homeodomain protein Scr is transcriptionally involved in the regulation of JH biosynthesis in the silkworm. PMID:26540044

  5. Effects of juvenile hormone analogs on new reproductives and colony growth of Pharaoh ant (Hymenoptera: Formicidae).

    PubMed

    Lim, S P; Lee, C Y

    2005-12-01

    Two juvenile hormone analogs (JHAs), pyriproxyfen and S-methoprene, were impregnated into dried tuna fish and fed to colonies of Monomorium pharaonis (L.) at very low concentrations (1.0, 2.0, 3.0, 4.0, and 5.0 microg/ml). Its effects on the production of sexuals and colonial growth were observed. Colonies treated with pyriproxyfen yielded sexuals with physical abnormalities. Both female and male sexuals developed bulbous wings, decreased melanization, and died shortly after emergence. Sexuals emerged from colonies treated with S-methoprene did not possess anomalous characteristics. Both pyriproxyfen and S-methoprene did not have significant effects on colonial growth because of the low concentrations of the baits. A commercial bait containing 0.3% S-methoprene (Bioprene-BM) also was evaluated for its efficacy on Pharaoh's ant colonies. Results showed that Pharaoh's ant colonies succumbed to the lethal effects of S-methoprene. Colony members were reduced significantly. Production of queens also decreased significantly in treated colonies and treated queens were unable to lay eggs. JHAs are slow acting and eliminate ant colonies at a relatively slow rate. At low concentrations, pyriproxyfen recorded baffling results, i.e., bulbous wings and demelanized exoskeleton, and it is vital that further studies are initiated to solidify these findings.

  6. Synthesis and bioassay of radiolabeled, chiral probes for juvenile hormone receptor study

    SciTech Connect

    Eng, W.

    1987-01-01

    Four different types of compounds were synthesized for the detailed study on interactions between insect juvenile hormone (JH) and the corresponding binding proteins, receptor proteins and catabolic enzymes: (1) High specific activity /sup 3/H-labeled, chiral alkyldiazoacetates with their skeletons approaching those of natural JH I and JH II were synthesized as photoaffinity labels for probing JH receptor proteins in Lepidoptera. Compared with epoxy farnesyl diazoacetate (EFDA), epoxy bishomofarnesyl diazoacetate (EBDA) and epoxy homofarnesyl diazoacetate (EHDA) have largely increased affinity to Manduca sexta JH binding proteins (JHBP) as demonstrated by gel electrophoresis. (2) Chiral JH I and JH II acids, as well as 12-hydroxy-JH I and JH II were synthesized. The hydroxy groups in these compounds provide tether points for attachment to proteins to serve as antigens with most of the recognition sites preserved to be used in JH radioimmunoassays. (3) The first radioiodine-labeled JH, (/sup 125/I)-12-iodo-JH I, was synthesized, both in no-carrier-added and carrier-added forms, as one of the probes for JH receptor study. (4) Four alkylthioltrifluoropropanones with skeletons approaching that of JH III and functional groups mimicking the JH epoxide moiety were synthesized as inhibitors for JH esterase (JHE).

  7. Juvenile hormone connects larval nutrition with target of rapamycin signaling in the mosquito Aedes aegypti.

    PubMed

    Shiao, Shin-Hong; Hansen, Immo A; Zhu, Jinsong; Sieglaff, Douglas H; Raikhel, Alexander S

    2008-01-01

    Anautogenous mosquitoes require blood meals to promote egg development. If adequate nutrients are not obtained during larval development, the resulting "small" sized adult mosquitoes require multiple blood meals for egg development; markedly increasing host-vector contacts and the likelihood of disease transmission. Nutrient-sensitive target of rapamycin (TOR) signaling is a key signaling pathway that links elevated hemolymph amino acid levels derived from the blood meal to the expression of yolk protein precursors in the fat body. Here we report that the blood-meal-induced activation of the TOR-signaling pathway and subsequent egg maturation depends on the accumulation of adequate nutritional reserves during larval development. We have established well-nourished, "standard" mosquitoes and malnourished, "small" mosquitoes as models to address this nutrient sensitive pathway. This regulatory mechanism involves juvenile hormone (JH), which acts as a mediator of fat body competence, permitting the response to amino acids derived from the blood meal. We demonstrate that treatment with JH results in recovery of the TOR molecular machinery, Aedes aegypti cationic amino acid transporter 2 (AaiCAT2), TOR, and S6 kinase (S6K), in fat bodies of small mosquitoes, enabling them to complete their first gonotrophic cycle after a single blood meal. These findings establish a direct link between nutrient reserves and the establishment of TOR signaling in mosquitoes.

  8. Glutamate-gated chloride channels inhibit juvenile hormone biosynthesis in the cockroach, Diploptera punctata.

    PubMed

    Liu, Hsin-Ping; Lin, Shu-Chen; Lin, Chi-Yen; Yeh, Shih-Rung; Chiang, Ann-Shyn

    2005-11-01

    Juvenile hormone (JH) synthesized and released from endocrine gland corpus allatum (CA) plays an important role in insect metamorphosis, vitellogenesis and reproduction. Glutamate is a major neurotransmitter in the nervous system and its activated receptors possess excitatory and inhibitory forms in muscle fibers of invertebrates. Previously, we have shown that the rise of intracellular calcium through excitatory glutamate receptors, N-methyl-d-aspartate (NMDA) and non-NMDA-type channels stimulates JH synthesis in the cockroach, Diploptera punctata. Here, we demonstrate the occurrence of inhibitory chloride permeable glutamate (GluCl) receptors on CA cell membranes. Application of the GluCl channel activators, ibotenic acid (Ibo) and ivermectin, but not gamma-aminobutyric acid caused a decline in JH synthesis in glands of either high or low activity during the gonadotrophic cycle. Also, while recording the membrane potential of the isolated whole CA glands intracellularly, Ibo induced a hyperpolarizated response. Both changes in the membrane potential and inhibition of JH synthesis could be abolished by the application of the chloride channel blocker picrotoxin. Finally, we found both excitatory and inhibitory glutamate receptors cause antagonistic effects on rates of JH synthesis. These results indicate a novel function of GluCl channels in the inhibition of JH synthesis that could be a potential pathway for developing a new generation of insecticides.

  9. Identification of plant compounds that disrupt the insect juvenile hormone receptor complex.

    PubMed

    Lee, Seok-Hee; Oh, Hyun-Woo; Fang, Ying; An, Saes-Byeol; Park, Doo-Sang; Song, Hyuk-Hwan; Oh, Sei-Ryang; Kim, Soo-Young; Kim, Seonghyun; Kim, Namjung; Raikhel, Alexander S; Je, Yeon Ho; Shin, Sang Woon

    2015-02-10

    Insects impact human health through vector-borne diseases and cause major economic losses by damaging crops and stored agricultural products. Insect-specific growth regulators represent attractive control agents because of their safety to the environment and humans. We identified plant compounds that serve as juvenile hormone antagonists (PJHANs). Using the yeast two-hybrid system transformed with the mosquito JH receptor as a reporter system, we demonstrate that PJHANs affect the JH receptor, methoprene-tolerant (Met), by disrupting its complex with CYCLE or FISC, formation of which is required for mediating JH action. We isolated five diterpene secondary metabolites with JH antagonist activity from two plants: Lindera erythrocarpa and Solidago serotina. They are effective in causing mortality of mosquito larvae at relatively low LD50 values. Topical application of two diterpenes caused reduction in the expression of Met target genes and retardation of follicle development in mosquito ovaries. Hence, the newly discovered PJHANs may lead to development of a new class of safe and effective pesticides.

  10. The role of juvenile hormone in competition and cooperation by burying beetles.

    PubMed

    Scott, Michelle Pellissier

    2006-10-01

    Few studies have addressed the physiological mechanisms that modulate aggression in insects. In some social insects, there is a correlation of JH and aggression in colony defense and in the establishment of dominance, but only a few studies demonstrate a causal relationship. Burying beetles aggressively defend a breeding resource, a carcass, and juvenile hormone (JH) hemolymph titers increase rapidly upon the discovery of a carcass. In this study, I show that treatment with the JH analog, methoprene, in the absence of a carcass increases the probability of injuries from aggressive interactions, but treatment to one member of a pair of competing Nicrophorus orbicollis females does not increase the probability that she will win control of the resource. In addition, higher JH levels are not associated with greater competitive ability in communally breeding Nicrophorus tomentosus females. Treatment of one female N. tomentosus does not increase her share of the communal brood. Methoprene seems to make a less competitive female more persistent and less willing to concede, which, although maintaining her share of reproduction, results in her exclusion from the brood chamber.

  11. Influences of Neighborhood Context, Individual History and Parenting Behavior on Recidivism among Juvenile Offenders

    ERIC Educational Resources Information Center

    Grunwald, Heidi E.; Lockwood, Brian; Harris, Philip W.; Mennis, Jeremy

    2010-01-01

    This study examined the effects of neighborhood context on juvenile recidivism to determine if neighborhoods influence the likelihood of reoffending. Although a large body of literature exists regarding the impact of environmental factors on delinquency, very little is known about the effects of these factors on juvenile recidivism. The sample…

  12. A new method of detecting hormone-binding proteins electroblotted onto glass fiber filter: juvenile hormone-binding proteins from grasshopper hemolymph.

    PubMed

    Jefferies, L S; Roberts, P E

    1990-03-01

    We have developed a new method to identify juvenile hormone (JH)-binding proteins blotted onto glass fiber filter (GFF) after electrophoretic separation. Insect JH regulates reproduction in the two-striped grasshopper, Melanoplus bivittatus. A number of proteins are involved in the delivery of JH from its site of synthesis to the nuclei of fat body cells where it acts to induce vitellogenesis. To identify JH binding proteins, hemolymph was separated by PAGE, electroblotted onto GFF, and incubated in [10-3H]JH-III. The amount of hormone bound by blotted proteins increased with the amount of protein on the filter, was competitively displaced by excess non-labeled hormone, and was affiliated with individual bands on fluorograms of proteins blotted after electrophoretic separation. GFF etched with trifluoroacetic acid was better than nitrocellulose, Zeta Probe, cellulose acetate or unetched GFF. Phosphate (pH 6.0-7.3) or Tris buffers (pH 7.3-8.0) worked equally well for the procedure. Unbound hormone was easily removed by short washes in buffer, and adequate binding for detection was achieved in a 15 min incubation. Preliminary data suggest that this technique may be used to detect receptors, carriers, and binding proteins of steroid hormones.

  13. Farnesyl phosphatase, a Corpora allata enzyme involved in juvenile hormone biosynthesis in Aedes aegypti.

    PubMed

    Nyati, Pratik; Nouzova, Marcela; Rivera-Perez, Crisalejandra; Clifton, Mark E; Mayoral, Jaime G; Noriega, Fernando G

    2013-01-01

    The juvenile hormones (JHs) are sesquiterpenoid compounds that play a central role in insect reproduction, development and behavior. The late steps of JH III biosynthesis in the mosquito Aedes aegypti involve the hydrolysis of farnesyl pyrophosphate (FPP) to farnesol (FOL), which is then successively oxidized to farnesal and farnesoic acid, methylated to form methyl farnesoate and finally transformed to JH III by a P450 epoxidase. The only recognized FPP phosphatase (FPPase) expressed in the corpora allata (CA) of an insect was recently described in Drosophila melanogaster (DmFPPase). In the present study we sought to molecularly and biochemically characterize the FPP phosphatase responsible for the transformation of FPP into FOL in the CA of A. aegypti. A search for orthologs of the DmFPPase in Aedes aegypti led to the identification of 3 putative FPPase paralogs expressed in the CA of the mosquito (AaFPPases-1, -2, and -3). The activities of recombinant AaFPPases were tested against general phosphatase substrates and isoprenoid pyrophosphates. Using a newly developed assay utilizing fluorescent tags, we analyzed AaFPPase activities in CA of sugar and blood-fed females. Double-stranded RNA (dsRNA) was used to evaluate the effect of reduction of AaFPPase mRNAs on JH biosynthesis. AaFPPase-1 and AaFPPase-2 are members of the NagD family of the Class IIA C2 cap-containing haloalkanoic acid dehalogenase (HAD) super family and efficiently hydrolyzed FPP into FOL. AaFPPase activities were different in CA of sugar and blood-fed females. Injection of dsRNAs resulted in a significant reduction of AaFPPase-1 and AaFPPase-2 mRNAs, but only reduction of AaFPPase-1 caused a significant decrease of JH biosynthesis. These results suggest that AaFPPase-1 is predominantly involved in the catalysis of FPP into FOL in the CA of A. aegypti.

  14. Hairy and Groucho mediate the action of juvenile hormone receptor Methoprene-tolerant in gene repression

    PubMed Central

    Saha, Tusar T.; Shin, Sang Woon; Dou, Wei; Roy, Sourav; Zhao, Bo; Hou, Yuan; Wang, Xue-Li; Zou, Zhen; Girke, Thomas; Raikhel, Alexander S.

    2016-01-01

    The arthropod-specific juvenile hormone (JH) controls numerous essential functions. Its involvement in gene activation is known to be mediated by the transcription factor Methoprene-tolerant (Met), which turns on JH-controlled genes by directly binding to E-box–like motifs in their regulatory regions. However, it remains unclear how JH represses genes. We used the Aedes aegypti female mosquito, in which JH is necessary for reproductive maturation, to show that a repressor, Hairy, is required for the gene-repressive action of JH and Met. The RNA interference (RNAi) screen for Met and Hairy in the Aedes female fat body revealed a large cohort of Met- and Hairy-corepressed genes. Analysis of selected genes from this cohort demonstrated that they are repressed by JH, but RNAi of either Met or Hairy renders JH ineffective in repressing these genes in an in vitro fat-body culture assay. Moreover, this JH action was prevented by the addition of the translational inhibitor cycloheximide (CHX) to the culture, indicating the existence of an indirect regulatory hierarchy. The lack of Hairy protein in the CHX-treated tissue was verified using immunoblot analysis, and the upstream regions of Met/Hairy-corepressed genes were shown to contain common binding motifs that interact with Hairy. Groucho (gro) RNAi silencing phenocopied the effect of Hairy RNAi knockdown, indicating that it is involved in the JH/Met/Hairy hierarchy. Finally, the requirement of Hairy and Gro for gene repression was confirmed in a cell transfection assay. Thus, our study has established that Hairy and its cofactor Gro mediate the repressive function of JH and Met. PMID:26744312

  15. MiR-2 family regulates insect metamorphosis by controlling the juvenile hormone signaling pathway

    PubMed Central

    Belles, Xavier

    2015-01-01

    In 2009 we reported that depletion of Dicer-1, the enzyme that catalyzes the final step of miRNA biosynthesis, prevents metamorphosis in Blattella germanica. However, the precise regulatory roles of miRNAs in the process have remained elusive. In the present work, we have observed that Dicer-1 depletion results in an increase of mRNA levels of Krüppel homolog 1 (Kr-h1), a juvenile hormone-dependent transcription factor that represses metamorphosis, and that depletion of Kr-h1 expression in Dicer-1 knockdown individuals rescues metamorphosis. We have also found that the 3′UTR of Kr-h1 mRNA contains a functional binding site for miR-2 family miRNAs (for miR-2, miR-13a, and miR-13b). These data suggest that metamorphosis impairment caused by Dicer-1 and miRNA depletion is due to a deregulation of Kr-h1 expression and that this deregulation is derived from a deficiency of miR-2 miRNAs. We corroborated this by treating the last nymphal instar of B. germanica with an miR-2 inhibitor, which impaired metamorphosis, and by treating Dicer-1-depleted individuals with an miR-2 mimic to allow nymphal-to-adult metamorphosis to proceed. Taken together, the data indicate that miR-2 miRNAs scavenge Kr-h1 transcripts when the transition from nymph to adult should be taking place, thus crucially contributing to the correct culmination of metamorphosis. PMID:25775510

  16. A role for juvenile hormone in the prepupal development of Drosophila melanogaster.

    PubMed

    Riddiford, Lynn M; Truman, James W; Mirth, Christen K; Shen, Yu-Chi

    2010-04-01

    To elucidate the role of juvenile hormone (JH) in metamorphosis of Drosophila melanogaster, the corpora allata cells, which produce JH, were killed using the cell death gene grim. These allatectomized (CAX) larvae were smaller at pupariation and died at head eversion. They showed premature ecdysone receptor B1 (EcR-B1) in the photoreceptors and in the optic lobe, downregulation of proliferation in the optic lobe, and separation of R7 from R8 in the medulla during the prepupal period. All of these effects of allatectomy were reversed by feeding third instar larvae on a diet containing the JH mimic (JHM) pyriproxifen or by application of JH III or JHM at the onset of wandering. Eye and optic lobe development in the Methoprene-tolerant (Met)-null mutant mimicked that of CAX prepupae, but the mutant formed viable adults, which had marked abnormalities in the organization of their optic lobe neuropils. Feeding Met(27) larvae on the JHM diet did not rescue the premature EcR-B1 expression or the downregulation of proliferation but did partially rescue the premature separation of R7, suggesting that other pathways besides Met might be involved in mediating the response to JH. Selective expression of Met RNAi in the photoreceptors caused their premature expression of EcR-B1 and the separation of R7 and R8, but driving Met RNAi in lamina neurons led only to the precocious appearance of EcR-B1 in the lamina. Thus, the lack of JH and its receptor Met causes a heterochronic shift in the development of the visual system that is likely to result from some cells 'misinterpreting' the ecdysteroid peaks that drive metamorphosis.

  17. MiR-2 family regulates insect metamorphosis by controlling the juvenile hormone signaling pathway.

    PubMed

    Lozano, Jesus; Montañez, Raúl; Belles, Xavier

    2015-03-24

    In 2009 we reported that depletion of Dicer-1, the enzyme that catalyzes the final step of miRNA biosynthesis, prevents metamorphosis in Blattella germanica. However, the precise regulatory roles of miRNAs in the process have remained elusive. In the present work, we have observed that Dicer-1 depletion results in an increase of mRNA levels of Krüppel homolog 1 (Kr-h1), a juvenile hormone-dependent transcription factor that represses metamorphosis, and that depletion of Kr-h1 expression in Dicer-1 knockdown individuals rescues metamorphosis. We have also found that the 3'UTR of Kr-h1 mRNA contains a functional binding site for miR-2 family miRNAs (for miR-2, miR-13a, and miR-13b). These data suggest that metamorphosis impairment caused by Dicer-1 and miRNA depletion is due to a deregulation of Kr-h1 expression and that this deregulation is derived from a deficiency of miR-2 miRNAs. We corroborated this by treating the last nymphal instar of B. germanica with an miR-2 inhibitor, which impaired metamorphosis, and by treating Dicer-1-depleted individuals with an miR-2 mimic to allow nymphal-to-adult metamorphosis to proceed. Taken together, the data indicate that miR-2 miRNAs scavenge Kr-h1 transcripts when the transition from nymph to adult should be taking place, thus crucially contributing to the correct culmination of metamorphosis.

  18. TGF-β signaling in insects regulates metamorphosis via juvenile hormone biosynthesis.

    PubMed

    Ishimaru, Yoshiyasu; Tomonari, Sayuri; Matsuoka, Yuji; Watanabe, Takahito; Miyawaki, Katsuyuki; Bando, Tetsuya; Tomioka, Kenji; Ohuchi, Hideyo; Noji, Sumihare; Mito, Taro

    2016-05-17

    Although butterflies undergo a dramatic morphological transformation from larva to adult via a pupal stage (holometamorphosis), crickets undergo a metamorphosis from nymph to adult without formation of a pupa (hemimetamorphosis). Despite these differences, both processes are regulated by common mechanisms that involve 20-hydroxyecdysone (20E) and juvenile hormone (JH). JH regulates many aspects of insect physiology, such as development, reproduction, diapause, and metamorphosis. Consequently, strict regulation of JH levels is crucial throughout an insect's life cycle. However, it remains unclear how JH synthesis is regulated. Here, we report that in the corpora allata of the cricket, Gryllus bimaculatus, Myoglianin (Gb'Myo), a homolog of Drosophila Myoglianin/vertebrate GDF8/11, is involved in the down-regulation of JH production by suppressing the expression of a gene encoding JH acid O-methyltransferase, Gb'jhamt In contrast, JH production is up-regulated by Decapentaplegic (Gb'Dpp) and Glass-bottom boat/60A (Gb'Gbb) signaling that occurs as part of the transcriptional activation of Gb'jhamt Gb'Myo defines the nature of each developmental transition by regulating JH titer and the interactions between JH and 20E. When Gb'myo expression is suppressed, the activation of Gb'jhamt expression and secretion of 20E induce molting, thereby leading to the next instar before the last nymphal instar. Conversely, high Gb'myo expression induces metamorphosis during the last nymphal instar through the cessation of JH synthesis. Gb'myo also regulates final insect size. Because Myo/GDF8/11 and Dpp/bone morphogenetic protein (BMP)2/4-Gbb/BMP5-8 are conserved in both invertebrates and vertebrates, the present findings provide common regulatory mechanisms for endocrine control of animal development.

  19. TGF-β signaling in insects regulates metamorphosis via juvenile hormone biosynthesis

    PubMed Central

    Ishimaru, Yoshiyasu; Tomonari, Sayuri; Matsuoka, Yuji; Watanabe, Takahito; Miyawaki, Katsuyuki; Bando, Tetsuya; Tomioka, Kenji; Ohuchi, Hideyo; Noji, Sumihare; Mito, Taro

    2016-01-01

    Although butterflies undergo a dramatic morphological transformation from larva to adult via a pupal stage (holometamorphosis), crickets undergo a metamorphosis from nymph to adult without formation of a pupa (hemimetamorphosis). Despite these differences, both processes are regulated by common mechanisms that involve 20-hydroxyecdysone (20E) and juvenile hormone (JH). JH regulates many aspects of insect physiology, such as development, reproduction, diapause, and metamorphosis. Consequently, strict regulation of JH levels is crucial throughout an insect’s life cycle. However, it remains unclear how JH synthesis is regulated. Here, we report that in the corpora allata of the cricket, Gryllus bimaculatus, Myoglianin (Gb’Myo), a homolog of Drosophila Myoglianin/vertebrate GDF8/11, is involved in the down-regulation of JH production by suppressing the expression of a gene encoding JH acid O-methyltransferase, Gb’jhamt. In contrast, JH production is up-regulated by Decapentaplegic (Gb’Dpp) and Glass-bottom boat/60A (Gb’Gbb) signaling that occurs as part of the transcriptional activation of Gb’jhamt. Gb’Myo defines the nature of each developmental transition by regulating JH titer and the interactions between JH and 20E. When Gb’myo expression is suppressed, the activation of Gb’jhamt expression and secretion of 20E induce molting, thereby leading to the next instar before the last nymphal instar. Conversely, high Gb’myo expression induces metamorphosis during the last nymphal instar through the cessation of JH synthesis. Gb’myo also regulates final insect size. Because Myo/GDF8/11 and Dpp/bone morphogenetic protein (BMP)2/4-Gbb/BMP5–8 are conserved in both invertebrates and vertebrates, the present findings provide common regulatory mechanisms for endocrine control of animal development. PMID:27140602

  20. Juvenile hormone and insulin suppress lipolysis between periods of lactation during tsetse fly pregnancy.

    PubMed

    Baumann, Aaron A; Benoit, Joshua B; Michalkova, Veronika; Mireji, Paul O; Attardo, Geoffrey M; Moulton, John K; Wilson, Thomas G; Aksoy, Serap

    2013-06-15

    Tsetse flies are viviparous insects that nurture a single intrauterine progeny per gonotrophic cycle. The developing larva is nourished by the lipid-rich, milk-like secretions from a modified female accessory gland (milk gland). An essential feature of the lactation process involves lipid mobilization for incorporation into the milk. In this study, we examined roles for juvenile hormone (JH) and insulin/IGF-like (IIS) signaling pathways during tsetse pregnancy. In particular, we examined the roles for these pathways in regulating lipid homeostasis during transitions between non-lactating (dry) and lactating periods. The dry period occurs over the course of oogenesis and embryogenesis, while the lactation period spans intrauterine larvigenesis. Genes involved in the JH and IIS pathways were upregulated during dry periods, correlating with lipid accumulation between bouts of lactation. RNAi suppression of Forkhead Box Sub Group O (FOXO) expression impaired lipolysis during tsetse lactation and reduced fecundity. Similar reduction of the JH receptor Methoprene tolerant (Met), but not its paralog germ cell expressed (gce), reduced lipid accumulation during dry periods, indicating functional divergence between Met and gce during tsetse reproduction. Reduced lipid levels following Met knockdown led to impaired fecundity due to inadequate fat reserves at the initiation of milk production. Both the application of the JH analog (JHA) methoprene and injection of insulin into lactating females increased stored lipids by suppressing lipolysis and reduced transcripts of lactation-specific genes, leading to elevated rates of larval abortion. To our knowledge, this study is the first to address the molecular physiology of JH and IIS in a viviparous insect, and specifically to provide a role for JH signaling through Met in the regulation of lipid metabolism during insect lactation.

  1. Molecular mechanism underlying juvenile hormone-mediated repression of precocious larval–adult metamorphosis

    PubMed Central

    Kayukawa, Takumi; Jouraku, Akiya; Ito, Yuka; Shinoda, Tetsuro

    2017-01-01

    Juvenile hormone (JH) represses precocious metamorphosis of larval to pupal and adult transitions in holometabolous insects. The early JH-inducible gene Krüppel homolog 1 (Kr-h1) plays a key role in the repression of metamorphosis as a mediator of JH action. Previous studies demonstrated that Kr-h1 inhibits precocious larval–pupal transition in immature larva via direct transcriptional repression of the pupal specifier Broad-Complex (BR-C). JH was recently reported to repress the adult specifier gene Ecdysone-induced protein 93F (E93); however, its mechanism of action remains unclear. Here, we found that JH suppressed ecdysone-inducible E93 expression in the epidermis of the silkworm Bombyx mori and in a B. mori cell line. Reporter assays in the cell line revealed that the JH-dependent suppression was mediated by Kr-h1. Genome-wide ChIP-seq analysis identified a consensus Kr-h1 binding site (KBS, 14 bp) located in the E93 promoter region, and EMSA confirmed that Kr-h1 directly binds to the KBS. Moreover, we identified a C-terminal conserved domain in Kr-h1 essential for the transcriptional repression of E93. Based on these results, we propose a mechanism in which JH-inducible Kr-h1 directly binds to the KBS site upstream of the E93 locus to repress its transcription in a cell-autonomous manner, thereby preventing larva from bypassing the pupal stage and progressing to precocious adult development. These findings help to elucidate the molecular mechanisms regulating the metamorphic genetic network, including the functional significance of Kr-h1, BR-C, and E93 in holometabolous insect metamorphosis. PMID:28096379

  2. Juvenile hormone acid methyltransferase: A key regulatory enzyme for insect metamorphosis

    PubMed Central

    Shinoda, Tetsuro; Itoyama, Kyo

    2003-01-01

    Juvenile hormone (JH) acid methyltransferase (JHAMT) is an enzyme that converts JH acids or inactive precursors of JHs to active JHs at the final step of JH biosynthesis pathway in insects. By fluorescent mRNA differential display, we have cloned a cDNA encoding JHAMT from the corpora allata (CA) of the silkworm, Bombyx mori (BmJHAMT). The BmJHAMT cDNA encodes an ORF of 278 aa with a calculated molecular mass of 32,544 Da. The predicted amino acid sequence contains a conserved S-adenosyl-l-methionine (SAM) binding motif found in the family of SAM-dependent methyltransferases. Purified N-terminal 6×His-tagged recombinant BmJHAMT protein expressed in Escherichia coli catalyzed conversion of farnesoic acid and JH acids I, II, and III to their cognate methyl esters in the presence of SAM, confirming that this cDNA encodes a functional JHAMT. Putative orthologs, DmJHAMT and AgJHAMT, were identified from the genome sequence of the fruit fly Drosophila melanogaster, and a malaria vector, Anopheles gambiae, respectively. Northern blot and quantitative RT-PCR analyses revealed that the BmJHAMT gene was expressed specifically in the CA throughout the third and fourth instar. At the beginning of the last (fifth) instar, the expression level of BmJHAMT declined rapidly and became undetectable by day 4 and remained so until pupation. Correlation of the BmJHAMT gene expression and the JH biosynthetic activity in the CA suggests that the transcriptional suppression of the BmJHAMT gene is crucial for the termination of JH biosynthesis in the CA, which is a prerequisite for the initiation of metamorphosis. PMID:14530389

  3. Bumblebees can be used in combination with juvenile hormone analogues and ecdysone agonists.

    PubMed

    Mommaerts, Veerle; Sterk, Guido; Smagghe, Guy

    2006-08-01

    This study examined the lethal and sublethal effects on the beneficial insect Bombus terrestris by two classes of insect growth regulators (IGRs) that are commercially used in agriculture to control pest insects. Three juvenile hormones analogues (JHAs) (pyriproxyfen, fenoxycarb and kinoprene) and two ecdysone agonists or moulting accelerating compounds (MACs) (tebufenozide and methoxyfenozide) were tested. The bumblebee workers were exposed to the insecticides via three different routes of exposure: dermally by topical contact, and orally via the drinking sugar water or the pollen. In the first series of experiments the IGRs were applied at their respective maximum field recommended concentration (MFRC). These risk hazard tests showed that the tested IGRs caused no acute toxicity on the workers, and any compound had an adverse effect on reproduction (production of males). In addition, larval development was followed in the treated nests compared with the controls. After application of the two MACs and the JHA fenoxycarb no adverse effects were observed on larval development. However, in the nests where the workers were exposed to the JHAs pyriproxyfen and kinoprene higher numbers of dead larvae were scored. These larvae were third and fourth instars, implying a lethal blockage of development before metamorphosis. In a second test, a series of dilutions was made for kinoprene, and these results revealed that only the MFRC caused a toxic effect on the larval development. On the other hand, kinoprene at lower concentrations (0.0650 mg ai/l) had a stimulatory effect on brood production. It was remarkable that ovaries of such treated dominant workers were longer and contained more eggs than in the controls. In a last experiment, the cuticular uptake was determined for a JHA and MAC to evaluate to what extent worker bees accumulate these classes of IGRs. Cuticular uptake ranged from 34 to 83% at 24 h after topical application. Overall, the obtained results indicate that

  4. A cytochrome P450 terpenoid hydroxylase linked to the suppression of insect juvenile hormone synthesis.

    PubMed

    Sutherland, T D; Unnithan, G C; Andersen, J F; Evans, P H; Murataliev, M B; Szabo, L Z; Mash, E A; Bowers, W S; Feyereisen, R

    1998-10-27

    A cDNA encoding a cytochrome P450 enzyme was isolated from a cDNA library of the corpora allata (CA) from reproductively active Diploptera punctata cockroaches. This P450 from the endocrine glands that produce the insect juvenile hormone (JH) is most closely related to P450 proteins of family 4 and was named CYP4C7. The CYP4C7 gene is expressed selectively in the CA; its message could not be detected in the fat body, corpora cardiaca, or brain, but trace levels of expression were found in the midgut and caeca. The levels of CYP4C7 mRNA in the CA, measured by ribonuclease protection assays, were linked to the activity cycle of the glands. In adult females, CYP4C7 expression increased immediately after the peak of JH synthesis, reaching a maximum on day 7, just before oviposition. mRNA levels then declined after oviposition and during pregnancy. The CYP4C7 protein was produced in Escherichia coli as a C-terminal His-tagged recombinant protein. In a reconstituted system with insect NADPH cytochrome P450 reductase, cytochrome b5, and NADPH, the purified CYP4C7 metabolized (2E,6E)-farnesol to a more polar product that was identified by GC-MS and by NMR as (10E)-12-hydroxyfarnesol. CYP4C7 converted JH III to 12-trans-hydroxy JH III and metabolized other JH-like sesquiterpenoids as well. This omega-hydroxylation of sesquiterpenoids appears to be a metabolic pathway in the corpora allata that may play a role in the suppression of JH biosynthesis at the end of the gonotrophic cycle.

  5. Juvenile hormone biosynthesis in the fall armyworm, Spodoptera frugiperda (Lepidoptera, Noctuidae).

    PubMed

    Range, Sebastian; Oeh, Uwe; Lorenz, Matthias W; Etzel, Winfried; Nauen, Ralf; Hoffmann, Klaus H

    2002-05-01

    The in vitro production of juvenile hormones (JH) was investigated by using corpora allata (CA) of larvae and corpora cardiaca-corpora allata (CC-CA) complexes of adult females of the fall armyworm Spodoptera frugiperda. In female moths, JH release was high compared to that in 5th and 6th instar larvae. Concentrations of 0.11-0.12 mM methionine, 180-200 mM Na(+), 5.8-8.3 mM K(+), 10-50 mM Ca(2+) and a pH range of 5.7-6.3 yielded optimal incorporation of L-[methyl-(3)H] methionine in vitro by CC-CA complexes. The highest hourly incorporation occurred during a 9-h incubation period following a 1.5-h lag-phase. JH release from CC-CA complexes of adult females was shown to be age-dependent with a peak value on day 2 (approx. 4 pmol h(-1) CA(-1)). By a combination of reversed phase (RP)- and normal phase (NP)-high performance liquid chromatography (HPLC), two major labelled products released by the complex were separated. One compound co-migrated with chemically synthesized JH II diol, the second compound with JH III diol. Only traces of JH II and III could be detected in some samples. Gland extracts also contained both the major radiolabelled products. Double labelling experiments using [3H]methionine and [14C]acetate confirmed their de novo synthesis in CC-CA complexes of female moths. The nature of chemically synthesized reference JH III diol was proved by LC-MS (ESI mass spectrometry) and 1H-NMR (nuclear magnetic resonance spectroscopy).

  6. Juvenile hormone-activated phospholipase C pathway enhances transcriptional activation by the methoprene-tolerant protein

    PubMed Central

    Liu, Pengcheng; Peng, Hong-Juan; Zhu, Jinsong

    2015-01-01

    Juvenile hormone (JH) is a key regulator of a wide diversity of developmental and physiological events in insects. Although the intracellular JH receptor methoprene-tolerant protein (MET) functions in the nucleus as a transcriptional activator for specific JH-regulated genes, some JH responses are mediated by signaling pathways that are initiated by proteins associated with plasma membrane. It is unknown whether the JH-regulated gene expression depends on the membrane-mediated signal transduction. In Aedes aegypti mosquitoes, we found that JH activated the phospholipase C (PLC) pathway and quickly increased the levels of inositol 1,4,5-trisphosphate, diacylglycerol, and intracellular calcium, leading to activation and autophosphorylation of calcium/calmodulin-dependent protein kinase II (CaMKII). When abdomens from newly emerged mosquitoes were cultured in vitro, the JH-activated gene expression was repressed substantially if specific inhibitors of PLC or CaMKII were added to the medium together with JH. In newly emerged female mosquitoes, RNAi-mediated depletion of PLC or CaMKII considerably reduced the expression of JH-responsive genes, including the Krüppel homolog 1 gene (AaKr-h1) and the early trypsin gene (AaET). JH-induced loading of MET to the promoters of AaKr-h1 and AaET was weakened drastically when either PLC or CaMKII was inactivated in the cultured tissues. Therefore, the results suggest that the membrane-initiated signaling pathway modifies the DNA-binding activity of MET via phosphorylation and thus facilitates the genomic responses to JH. In summary, this study reveals an interplay of genomic and nongenomic signaling mechanisms of JH. PMID:25825754

  7. Hormonal alterations in PCOS and its influence on bone metabolism.

    PubMed

    Krishnan, Abhaya; Muthusami, Sridhar

    2017-02-01

    According to the World Health Organization (WHO) polycystic ovary syndrome (PCOS) occurs in 4-8% of women worldwide. The prevalence of PCOS in Indian adolescents is 12.2% according to the Indian Council of Medical Research (ICMR). The National Institute of Health has documented that it affects approximately 5 million women of reproductive age in the United States. Hormonal imbalance is the characteristic of many women with polycystic ovarian syndrome (PCOS). The influence of various endocrine changes in PCOS women and their relevance to bone remains to be documented. Hormones, which include gonadotrophin-releasing hormone (GnRH), insulin, the leutinizing/follicle-stimulating hormone (LH/FSH) ratio, androgens, estrogens, growth hormones (GH), cortisol, parathyroid hormone (PTH) and calcitonin are disturbed in PCOS women. These hormones influence bone metabolism in human subjects directly as well as indirectly. The imbalance in these hormones results in increased prevalence of osteoporosis in PCOS women. Limited evidence suggests that the drugs taken during the treatment of PCOS increase the risk of bone fracture in PCOS patients through endocrine disruption. This review is aimed at the identification of the relationship between bone mineral density and hormonal changes in PCOS subjects and identifies potential areas to study bone-related disorders in PCOS women. © 2017 Society for Endocrinology.

  8. Modeling the flux of metabolites in the juvenile hormone biosynthesis pathway using generalized additive models and ordinary differential equations

    PubMed Central

    Martínez-Rincón, Raúl O.; Rivera-Pérez, Crisalejandra; Diambra, Luis; Noriega, Fernando G.

    2017-01-01

    Juvenile hormone (JH) regulates development and reproductive maturation in insects. The corpora allata (CA) from female adult mosquitoes synthesize fluctuating levels of JH, which have been linked to the ovarian development and are influenced by nutritional signals. The rate of JH biosynthesis is controlled by the rate of flux of isoprenoids in the pathway, which is the outcome of a complex interplay of changes in precursor pools and enzyme levels. A comprehensive study of the changes in enzymatic activities and precursor pool sizes have been previously reported for the mosquito Aedes aegypti JH biosynthesis pathway. In the present studies, we used two different quantitative approaches to describe and predict how changes in the individual metabolic reactions in the pathway affect JH synthesis. First, we constructed generalized additive models (GAMs) that described the association between changes in specific metabolite concentrations with changes in enzymatic activities and substrate concentrations. Changes in substrate concentrations explained 50% or more of the model deviances in 7 of the 13 metabolic steps analyzed. Addition of information on enzymatic activities almost always improved the fitness of GAMs built solely based on substrate concentrations. GAMs were validated using experimental data that were not included when the model was built. In addition, a system of ordinary differential equations (ODE) was developed to describe the instantaneous changes in metabolites as a function of the levels of enzymatic catalytic activities. The results demonstrated the ability of the models to predict changes in the flux of metabolites in the JH pathway, and can be used in the future to design and validate experimental manipulations of JH synthesis. PMID:28158248

  9. Modeling the flux of metabolites in the juvenile hormone biosynthesis pathway using generalized additive models and ordinary differential equations.

    PubMed

    Martínez-Rincón, Raúl O; Rivera-Pérez, Crisalejandra; Diambra, Luis; Noriega, Fernando G

    2017-01-01

    Juvenile hormone (JH) regulates development and reproductive maturation in insects. The corpora allata (CA) from female adult mosquitoes synthesize fluctuating levels of JH, which have been linked to the ovarian development and are influenced by nutritional signals. The rate of JH biosynthesis is controlled by the rate of flux of isoprenoids in the pathway, which is the outcome of a complex interplay of changes in precursor pools and enzyme levels. A comprehensive study of the changes in enzymatic activities and precursor pool sizes have been previously reported for the mosquito Aedes aegypti JH biosynthesis pathway. In the present studies, we used two different quantitative approaches to describe and predict how changes in the individual metabolic reactions in the pathway affect JH synthesis. First, we constructed generalized additive models (GAMs) that described the association between changes in specific metabolite concentrations with changes in enzymatic activities and substrate concentrations. Changes in substrate concentrations explained 50% or more of the model deviances in 7 of the 13 metabolic steps analyzed. Addition of information on enzymatic activities almost always improved the fitness of GAMs built solely based on substrate concentrations. GAMs were validated using experimental data that were not included when the model was built. In addition, a system of ordinary differential equations (ODE) was developed to describe the instantaneous changes in metabolites as a function of the levels of enzymatic catalytic activities. The results demonstrated the ability of the models to predict changes in the flux of metabolites in the JH pathway, and can be used in the future to design and validate experimental manipulations of JH synthesis.

  10. Effects of temperature on reproductive output, egg provisioning, juvenile hormone and vitellogenin titres in the butterfly Bicyclus anynana.

    PubMed

    Geister, Thorin L; Lorenz, Matthias W; Meyering-Vos, Martina; Hoffmann, Klaus H; Fischer, Klaus

    2008-08-01

    Environmentally induced phenotypic plasticity is common in nature. Hormones, affecting multiple traits and signaling to a variety of distant target tissues, provide a mechanistic link between environments, genes and trait expression, and may therefore well be involved in the regulation phenotypic plasticity. Here, we investigate whether in the tropical butterfly Bicyclus anynana temperature-mediated plasticity in egg size and number, with fewer but larger eggs produced at lower temperatures and vice versa, is under control of juvenile hormone, and whether different temperatures cause differences in egg composition. Female B. anynana butterflies showed the expected response to temperature, however, we found no evidence for an involvement of juvenile hormone. Neither haemolymph JH II and JH III titres nor vitellogenin levels differed across temperatures. The smaller eggs produced at the higher temperature contained relatively higher amounts of water, free carbohydrates and proteins, but relatively lower amounts of lipids. While these smaller eggs had a lower absolute energy content, total reproductive investment was higher at the higher temperature (due to a higher fecundity). Overall, our study indicates that temperature-mediated plasticity in reproduction in B. anynana is mechanistically related to a biophysical model, with oocyte production (differentiation) and oocyte growth (vitellogenesis) having differential temperature sensitivities.

  11. Effects of the use of growth hormone in children and adolescents with juvenile idiopathic arthritis: a systematic review.

    PubMed

    Frittoli, Renan Bazuco; Longui, Barbara Sugui; Silva, Amanda Meireles; Filho, Antônio de Azevedo Barros; Monteiro, Maria Ângela Reis de Góes; Appenzeller, Simone

    Children with juvenile idiopathic arthritis (JIA) often have impaired growth and short stature. There is evidence that the therapeutic use of growth hormone (GH) is useful and safe in these patients. To analyze the effects of GH use in patients with JIA. A systematic review of the literature over the last 18 years in Medline and Embase databases. The criteria were analyzed independently by the researchers. We used the following keywords: "growth hormone", "arthritis, juvenile", "arthritis, rheumatoid", "child" and "adolescent". Among the 192 identified articles, 20 corresponded to the inclusion criteria. Seventeen longitudinal studies and 3 case reports were found. Most studies analyzed observed increased growth, muscle mass and bone mass using GH. Adverse effects observed were glucose intolerance, diabetes, bone deformities, osteonecrosis, reactivation of the disease and low final height. The majority of studies reported positive effects after the therapeutic use of GH, but some variability in response to treatment was observed. The combination of growth hormone with other drugs seems to be a good option. Copyright © 2016. Published by Elsevier Editora Ltda.

  12. Effects of the use of growth hormone in children and adolescents with juvenile idiopathic arthritis: a systematic review.

    PubMed

    Frittoli, Renan Bazuco; Longui, Barbara Sugui; Silva, Amanda Meireles; Filho, Antônio de Azevedo Barros; Monteiro, Maria Ângela Reis de Góes; Appenzeller, Simone

    2016-07-09

    Children with Juvenile Idiopathic Arthritis (JIA) often have impaired growth and short stature. There is evidence that the therapeutic use of growth hormone (GH) is useful and safe in these patients. To analyze the effects of GH use in patients with JIA. A systematic review of the literature over the last 18 years in Medline and Embase databases. The criteria were analyzed independently by the researchers. We used the following keywords: "growth hormone", "arthritis, juvenile", "arthritis, rheumatoid", "child" and "adolescent". Among the 192 identified articles, 20 corresponded to the inclusion criteria. Seventeen longitudinal studies and 3 case reports were found. Most studies analyzed observed increased growth, muscle mass and bone mass using GH. Adverse effects observed were glucose intolerance, diabetes, bone deformities, osteonecrosis, reactivation of the disease and low final height. The majority of studies reported positive effects after the therapeutic use of GH, but some variability in response to treatment was observed. The combination of growth hormone with other drugs seems to be a good option. Copyright © 2016. Published by Elsevier Editora Ltda.

  13. Sex and Hormonal influences on Seizures and Epilepsy

    PubMed Central

    Velíšková, Jana; DeSantis, Kara A.

    2012-01-01

    Epilepsy is the third most common chronic neurological disorder. Clinical and experimental evidence supports the role of sex and influence of sex hormones on seizures and epilepsy as well as alterations of the endocrine system and levels of sex hormones by epileptiform activity. Conversely, seizures are sensitive to changes in sex hormone levels, which in turn may affect the seizure-induced neuronal damage. The effects of reproductive hormones on neuronal excitability and seizure-induced damage are complex to contradictory and depend on different mechanisms, which have to be accounted for in data interpretation. Both estradiol and progesterone/allopregnanolone may have beneficial effects for patients with epilepsy. Individualized hormonal therapy should be considered as adjunctive treatment in patients with epilepsy to improve seizure control as well as quality of life. PMID:22504305

  14. Pleiotropic effects of juvenile hormone in ant queens and the escape from the reproduction-immunocompetence trade-off.

    PubMed

    Pamminger, Tobias; Treanor, David; Hughes, William O H

    2016-01-13

    The ubiquitous trade-off between survival and costly reproduction is one of the most fundamental constraints governing life-history evolution. In numerous animals, gonadotropic hormones antagonistically suppressing immunocompetence cause this trade-off. The queens of many social insects defy the reproduction-survival trade-off, achieving both an extraordinarily long life and high reproductive output, but how they achieve this is unknown. Here we show experimentally, by integrating quantification of gene expression, physiology and behaviour, that the long-lived queens of the ant Lasius niger have escaped the reproduction-immunocompetence trade-off by decoupling the effects of a key endocrine regulator of fertility and immunocompetence in solitary insects, juvenile hormone (JH). This modification of the regulatory architecture enables queens to sustain a high reproductive output without elevated JH titres and suppressed immunocompetence, providing an escape from the reproduction-immunocompetence trade-off that may contribute to the extraordinary lifespan of many social insect queens.

  15. 20-hydroxyecdysone and juvenile hormone analog prevent precocious metamorphosis in recessive trimolter mutants of Bombyx mori.

    PubMed

    Wang, Hua-Bing; Ali, Saheb Md; Moriyama, Minoru; Iwanaga, Masashi; Kawasaki, Hideki

    2012-02-01

    The trimolter mutants of Bombyx mori have four instead of five larval instars of normal tetramolters. Here, we show that the tetramolter was induced in the recessive trimolter European No.7 mutant (rt-E7) by application of either the juvenile hormone analog (JHA) or 20-hydroxyecdysone (20E). However, treatments with JHA or 20E did not change the number of larval instars of the dominant trimolter Si Chuan mutant (DT-SC). Krüppel-homolog 1 (Kr-h1) is an early JH-response gene that mediates the anti-metamorphic action of JH. In the wing disc of tetramolter B. mori, Kr-h1 RNAs decreased shortly after ecdysis to the fifth instar, while pupal specifier gene, Broad Complex Z1 (BR-Z1) RNAs slightly increased and coincided with the onset of metamorphic competence of wing discs. Analysis of the developmental profile of Kr-h1 in the wing disc of rt-E7 showed that its transcript slightly increased from 12 to 24 h and gradually decreased between 24 and 72 h in the fourth (last) larval instar, while Kr-h1 mRNA decreased rapidly between 12 and 72 h in DT-SC. In addition, the expression of BR-Z1 in DT-SC during the early fourth (last) larval instar is relatively higher than that in rt-E7. These results indicated that the occurrence of pupal commitment of the wing disc in DT-SC was much earlier than that in rt-E7. In the early fourth larval instar of rt-E7, feeding on 20E or treatments with exogenous JHA caused up-regulation of Kr-h1, suppressed premature induction of BR-Z1, and then induced an additional larval instar. By contrast, in DT-SC mutant, since pupal commitment immediately occurred after third ecdysis, precocious metamorphosis was not successfully rescued. The results suggest that Kr-h1 and BR-Z1 involved in the prevention of precocious metamorphosis in recessive trimolter mutants by application of 20E and JHA. The result indicated that Kr-h1 and BR-Z1 expression reflected larval-pupal transition of the recessive trimolter of B. mori. Copyright © 2011 Elsevier Ltd

  16. The influence of growth hormone on bone and adipose programming.

    PubMed

    Oberbauer, Anita M

    2014-01-01

    In utero growth hormone exposure is associated with distinct immediate growth responses and long term impacts on adult physiological parameters that include obesity, insulin resistance, and bone function. Growth hormone accelerates cellular proliferation in many tissues but is exemplified by increases in the number of cells within the cartilaginous growth plate of bone. In some cases growth hormone also potentiates differentiation as seen in the differentiation of adipocytes that rapidly fill upon withdrawal of growth hormone. Growth hormone provokes these changes either by direct action or through intermediaries such as insulin-like growth factor-I and other downstream effector molecules. The specific mechanism used by growth hormone in programming tissues is not yet fully characterized and likely represents a multipronged approach involving DNA modification, altered adult hormonal milieu, and the development of an augmented stem cell pool capable of future engagement as is seen in adipose accrual. This review summarizes findings of growth hormone's influence on in utero and neonatal cellular and metabolic profiles related to bone and adipose tissue.

  17. Coordination of deiodinase and thyroid hormone receptor expression during the larval to juvenile transition in sea bream (Sparus aurata, Linnaeus).

    PubMed

    Campinho, Marco António; Galay-Burgos, Malyka; Sweeney, Glen E; Power, Deborah Mary

    2010-01-15

    To test the hypothesis that THs play an important role in the larval to juvenile transition in the marine teleost model, sea bream (Sparus auratus), key elements of the thyroid axis were analysed during development. Specific RT-PCR and Taqman quantitative RT-PCR were established and used to measure sea bream iodothyronine deiodinases and thyroid hormone receptor (TR) genes, respectively. Expression of deiodinases genes (D1 and D2) which encode enzymes producing T3, TRs and T4 levels start to increase at 20-30 days post-hatch (dph; beginning of metamorphosis), peak at about 45 dph (climax) and decline to early larval levels after 90-100 dph (end of metamorphosis) when fish are fully formed juveniles. The profile of these different TH elements during sea bream development is strikingly similar to that observed during the TH driven metamorphosis of flatfish and suggests that THs play an analogous role in the larval to juvenile transition in this species and probably also in other pelagic teleosts. However, the effect of T3 treatment on deiodinases and TR transcript abundance in sea bream is not as clear cut as in larval flatfish and tadpoles indicating divergence in the responsiveness of TH axis elements and highlighting the need for further studies of this axis during development of fish.

  18. Immune Deficiency Influences Juvenile Social Behavior and Maternal Behavior

    PubMed Central

    Quinnies, Kayla M.; Cox, Kimberly H.; Rissman, Emilie F.

    2017-01-01

    Mice with severe combined immunodeficiency (SCID) lack functional T and B-lymphocytes, and have impaired cognitive abilities. Here, we assessed social behaviors in male SCID and C57BL/6 (B6) juvenile mice. In a social preference task, SCID mice spent more time than B6 mice investigating a novel adult male mouse. In a social recognition task, SCID mice habituated to a novel ovariectomized mouse, but failed to show dishabituation when presented with an unfamiliar individual. We hypothesized that partial immune restoration could normalize behaviors. SCID pups (postnatal day 7) received either saline or splenocytes from normal donors. Splenocyte-replaced SCID mice spent less time interacting with a novel mouse than saline-injected SCID or B6 control mice. Again, control SCID mice failed to dishabituate to a novel mouse, but splenocyte-replaced SCID mice showed dishabituation. In both of these studies B6 and SCID pairs were used to produce offspring that remained with their dams until weaning. There are no studies of maternal behavior in SCID dams; therefore to investigate the potential role for this factor we quantified maternal behavior in SCID and B6 dams; several significant differences were found. To control for differences in maternal care we mated heterozygous SCIDs to produce offspring. These homozygous SCID and WT offspring reared by dams of the same genotypes displayed similar responses to a novel mouse; however, in the social recognition task SCID males did not display dishabituation to a novel mouse. Taken together, our data indicate that gene by environment interactions influence social interactions in immune deficient mice. PMID:26030431

  19. TOR Pathway-Mediated Juvenile Hormone Synthesis Regulates Nutrient-Dependent Female Reproduction in Nilaparvata lugens (Stål).

    PubMed

    Lu, Kai; Chen, Xia; Liu, Wen-Ting; Zhou, Qiang

    2016-03-28

    The "target of rapamycin" (TOR) nutritional signaling pathway and juvenile hormone (JH) regulation of vitellogenesis has been known for a long time. However, the interplay between these two pathways regulating vitellogenin (Vg) expression remains obscure. Here, we first demonstrated the key role of amino acids (AAs) in activation of Vg synthesis and egg development in Nilaparvata lugens using chemically defined artificial diets. AAs induced the expression of TOR and S6K (S6 kinase), whereas RNAi-mediated silencing of these two TOR pathway genes and rapamycin application strongly inhibited the AAs-induced Vg synthesis. Furthermore, knockdown of Rheb (Ras homologue enriched in brain), TOR, S6K and application of rapamycin resulted in a dramatic reduction in the mRNA levels of jmtN (juvenile hormone acid methyltransferase, JHAMT). Application of JH III on the RNAi (Rheb and TOR) and rapamycin-treated females partially rescued the Vg expression. Conversely, knockdown of either jmtN or met (methoprene-tolerant, JH receptor) and application of JH III had no effects on mRNA levels of Rheb, TOR and S6K and phosphorylation of S6K. In summary, our results demonstrate that the TOR pathway induces JH biosynthesis that in turn regulates AAs-mediated Vg synthesis in N. lugens.

  20. TOR Pathway-Mediated Juvenile Hormone Synthesis Regulates Nutrient-Dependent Female Reproduction in Nilaparvata lugens (Stål)

    PubMed Central

    Lu, Kai; Chen, Xia; Liu, Wen-Ting; Zhou, Qiang

    2016-01-01

    The “target of rapamycin” (TOR) nutritional signaling pathway and juvenile hormone (JH) regulation of vitellogenesis has been known for a long time. However, the interplay between these two pathways regulating vitellogenin (Vg) expression remains obscure. Here, we first demonstrated the key role of amino acids (AAs) in activation of Vg synthesis and egg development in Nilaparvata lugens using chemically defined artificial diets. AAs induced the expression of TOR and S6K (S6 kinase), whereas RNAi-mediated silencing of these two TOR pathway genes and rapamycin application strongly inhibited the AAs-induced Vg synthesis. Furthermore, knockdown of Rheb (Ras homologue enriched in brain), TOR, S6K and application of rapamycin resulted in a dramatic reduction in the mRNA levels of jmtN (juvenile hormone acid methyltransferase, JHAMT). Application of JH III on the RNAi (Rheb and TOR) and rapamycin-treated females partially rescued the Vg expression. Conversely, knockdown of either jmtN or met (methoprene-tolerant, JH receptor) and application of JH III had no effects on mRNA levels of Rheb, TOR and S6K and phosphorylation of S6K. In summary, our results demonstrate that the TOR pathway induces JH biosynthesis that in turn regulates AAs-mediated Vg synthesis in N. lugens. PMID:27043527

  1. Nutritional Signaling Regulates Vitellogenin Synthesis and Egg Development through Juvenile Hormone in Nilaparvata lugens (Stål)

    PubMed Central

    Lu, Kai; Chen, Xia; Liu, Wen-Ting; Zhang, Xin-Yu; Chen, Ming-Xiao; Zhou, Qiang

    2016-01-01

    Insect female reproduction which comprises the synthesis of vitellogenein (Vg) in the fat body and its incorporation into developing oocytes, needs a large amount of energy and food resources. Our previous studies found that juvenile hormone (JH) regulates vitellogenesis in the brown planthopper, Nilaparvata lugens. Here, we report on the role of JH in nutrient-regulated Vg synthesis and egg development. We first cloned the genes coding for juvenile hormone acid methyltransferase (JHAMT) which is involved in JH biosynthesis and methoprene-tolerant (Met) for JH action. Amino acids (AAs) induced the expression of jmtN, while showing no effects on the expression of met using an artificial diet culture system. Reduction in JH biosynthesis or its action by RNA interference (RNAi)-mediated silencing of jmtN or met led to a severe inhibition of AAs-induced Vg synthesis and oocyte maturation, together with lower fecundity. Furthermore, exogenous application of JH III partially restored Vg expression levels in jmtN RNAi females. However, JH III application did not rescue Vg synthesis in these met RNAi insects. Our results show that AAs induce Vg synthesis in the fat body and egg development in concert with JH biosynthesis in Nilaparvata lugens (Stål), rather than through JH action. PMID:26927076

  2. Nutritional Signaling Regulates Vitellogenin Synthesis and Egg Development through Juvenile Hormone in Nilaparvata lugens (Stål).

    PubMed

    Lu, Kai; Chen, Xia; Liu, Wen-Ting; Zhang, Xin-Yu; Chen, Ming-Xiao; Zhou, Qiang

    2016-02-26

    Insect female reproduction which comprises the synthesis of vitellogenein (Vg) in the fat body and its incorporation into developing oocytes, needs a large amount of energy and food resources. Our previous studies found that juvenile hormone (JH) regulates vitellogenesis in the brown planthopper, Nilaparvata lugens. Here, we report on the role of JH in nutrient-regulated Vg synthesis and egg development. We first cloned the genes coding for juvenile hormone acid methyltransferase (JHAMT) which is involved in JH biosynthesis and methoprene-tolerant (Met) for JH action. Amino acids (AAs) induced the expression of jmtN, while showing no effects on the expression of met using an artificial diet culture system. Reduction in JH biosynthesis or its action by RNA interference (RNAi)-mediated silencing of jmtN or met led to a severe inhibition of AAs-induced Vg synthesis and oocyte maturation, together with lower fecundity. Furthermore, exogenous application of JH III partially restored Vg expression levels in jmtN RNAi females. However, JH III application did not rescue Vg synthesis in these met RNAi insects. Our results show that AAs induce Vg synthesis in the fat body and egg development in concert with JH biosynthesis in Nilaparvata lugens (Stål), rather than through JH action.

  3. The nature and development of sex attractant specificity in cockroaches of the genus Periplaneta. IV. electrophysiological study of attractant specificity and its determination by juvenile hormone.

    PubMed

    Schafer, R

    1977-02-01

    The antennae of male Periplaneta americana acquire a large number of olfactory receptors at the adult stage. Electrophysiological methods (single unit and electroantennogram recording) show that a portion of the receptors added at the adult ecdysis are sex attractant receptors. Sex attractant receptors are not present in large numbers on larval and adult female antennae. The differentiation of pheromone receptors is inhibited during normal larval development by juvenile hormone. Topical application of juvenile hormone-mimic to male antennae during the terminal larval instar inhibits their development. Comparative electrophysiological studies indicate a high degree of cross-reactivity of the P. americana sex attractant among four other species within the genus Periplaneta.

  4. Developmental abnormalities of the gonad and abnormal sex hormone concentrations in juvenile alligators from contaminated and control lakes in Florida.

    PubMed Central

    Guillette, L J; Gross, T S; Masson, G R; Matter, J M; Percival, H F; Woodward, A R

    1994-01-01

    The reproductive development of alligators from a contaminated and a control lake in central Florida was examined. Lake Apopka is adjacent to an EPA Superfund site, listed due to an extensive spill of dicofol and DDT or its metabolites. These compounds can act as estrogens. Contaminants in the lake also have been derived from extensive agricultural activities around the lake that continue today and a sewage treatment facility associated with the city of Winter Garden, Florida. We examined the hypothesis that an estrogenic contaminant has caused the current failure in recruitment of alligators on Lake Apopka. Supporting data include the following: At 6 months of age, female alligators from Lake Apopka had plasma estradiol-17 beta concentrations almost two times greater than normal females from the control lake, Lake Woodruff. The Apopka females exhibited abnormal ovarian morphology with large numbers of polyovular follicles and polynuclear oocytes. Male juvenile alligators had significantly depressed plasma testosterone concentrations comparable to levels observed in normal Lake Woodruff females but more than three times lower than normal Lake Woodruff males. Additionally, males from Lake Apopka had poorly organized testes and abnormally small phalli. The differences between lakes and sexes in plasma hormone concentrations of juvenile alligators remain even after stimulation with luteinizing hormone. Our data suggest that the gonads of juveniles from Lake Apopka have been permanently modified in ovo, so that normal steroidogenesis is not possible, and thus normal sexual maturation is unlikely. Images p680-a Figure 1. Figure 2. Figure 3. A Figure 3. B Figure 3. C Figure 4. A Figure 4. B Figure 4. C Figure 4. D Figure 5. A Figure 5. B Figure 5. C PMID:7895709

  5. The Time- and Age-dependent Effects of the Juvenile Hormone Analog Pesticide, Pyriproxyfen on Daphnia magna Reproduction

    PubMed Central

    Ginjupalli, Gautam K.; Baldwin, William S.

    2013-01-01

    Pyriproxyfen is an insecticidal juvenile hormone analog that perturbs insect and tick development. Pyriproxyfen also alters parthenogenic reproduction in non-target cladoceran species as it induces male production that can lead to a decrease in fecundity, a reduction in population density, and subsequent ecological effects. In this study, we investigate the impacts of pyriproxyfen on Daphnia magna reproduction using a series of male production screening assays. These assays demonstrate that pyriproxyfen increases male production in a concentration-dependent fashion with an EC50 of 156 pM (50.24 ng L-1); a concentration considered environmentally relevant. Furthermore, pyriproxyfen decreases overall fecundity at all ages tested (7, 14, 21-d old female parthenogenic daphnids). Juvenile (3-d old) and reproductively mature (10-d old) female daphnids were also exposed to 155 pM pyriproxyfen for 2 – 12 d and reproduction measured for 16 d to compare the effects of short-term and prolonged exposures, and determine the potential for recovery. Results indicate that longer pyriproxyfen exposures (8–12 d) extend male production and decrease reproduction; however, daphnids exposed for only 2–4 d recover and produce a relatively normal abundance of neonates. In addition, juvenile daphnids are also very sensitive to pyriproxyfen, but the primary effect on juvenile daphnids is reduced reproduction and protracted development not male production. Taken together, continued use of pyriproxyfen around water bodies needs due caution because of its potential adverse effects with significant developmental delays and male production compounded by prolonged exposure. PMID:23714148

  6. The time- and age-dependent effects of the juvenile hormone analog pesticide, pyriproxyfen on Daphnia magna reproduction.

    PubMed

    Ginjupalli, Gautam K; Baldwin, William S

    2013-08-01

    Pyriproxyfen is an insecticidal juvenile hormone analog that perturbs insect and tick development. Pyriproxyfen also alters parthenogenic reproduction in non-target cladoceran species as it induces male production that can lead to a decrease in fecundity, a reduction in population density, and subsequent ecological effects. In this study, we investigate the impacts of pyriproxyfen on Daphnia magna reproduction using a series of male production screening assays. These assays demonstrate that pyriproxyfen increases male production in a concentration-dependent fashion with an EC50 of 156pM (50.24ngL(-1)); a concentration considered environmentally relevant. Furthermore, pyriproxyfen decreases overall fecundity at all ages tested (7, 14, 21-d old female parthenogenic daphnids). Juvenile (3-d old) and reproductively mature (10-d old) female daphnids were also exposed to 155pM pyriproxyfen for 2-12d and reproduction measured for 16d to compare the effects of short-term and prolonged exposures, and determine the potential for recovery. Results indicate that longer pyriproxyfen exposures (8-12d) extend male production and decrease reproduction; however, daphnids exposed for only 2-4d recover and produce a relatively normal abundance of neonates. In addition, juvenile daphnids are also very sensitive to pyriproxyfen, but the primary effect on juvenile daphnids is reduced reproduction and protracted development not male production. Taken together, continued use of pyriproxyfen around water bodies needs due caution because of its potential adverse effects with significant developmental delays and male production compounded by prolonged exposure.

  7. Female hormones: do they influence muscle and tendon protein metabolism?

    PubMed

    Hansen, Mette

    2017-08-29

    Due to increased longevity, women can expect to live more than one-third of their lives in a post-menopausal state, which is characterised by low circulating levels of oestrogen and progesterone. The aim of this review is to provide insights into current knowledge of the effect of female hormones (or lack of female hormones) on skeletal muscle protein turnover at rest and in response to exercise. This review is primarily based on data from human trials. Many elderly post-menopausal women experience physical disabilities and loss of independence related to sarcopenia, which reduces life quality and is associated with substantial financial costs. Resistance training and dietary optimisation can counteract or at least decelerate the degenerative ageing process, but lack of oestrogen in post-menopausal women may reduce their sensitivity to these anabolic stimuli and accelerate muscle loss. Tendons and ligaments are also affected by sex hormones, but the effect seems to differ between endogenous and exogenous female hormones. Furthermore, the effect seems to depend on the age, and as a result influence the biomechanical properties of the ligaments and tendons differentially. Based on the present knowledge oestrogen seems to play a significant role with regard to skeletal muscle protein turnover. Therefore, oestrogen/hormonal replacement therapy may counteract the degenerative changes in skeletal muscle. Nevertheless, there is a need for greater insight into the direct and indirect mechanistic effects of female hormones before any evidence-based recommendations regarding type, dose, duration and timing of hormone replacement therapy can be provided.

  8. Exposure of juvenile turbot (Scophthalmus maximus) to silver nanoparticles and 17α-ethinylestradiol mixtures: Implications for contaminant uptake and plasma steroid hormone levels.

    PubMed

    Farkas, Julia; Salaberria, Iurgi; Styrishave, Bjarne; Staňková, Radka; Ciesielski, Tomasz M; Olsen, Anders J; Posch, Wilfried; Flaten, Trond P; Krøkje, Åse; Salvenmoser, Willi; Jenssen, Bjørn M

    2017-01-01

    Combined exposure to engineered nanoparticles (ENPs) and anthropogenic contaminants can lead to changes in bioavailability, uptake and thus effects of both groups of contaminants. In this study we investigated effects of single and combined exposures of silver (Ag) nanoparticles (AgNPs) and the synthetic hormone 17α-ethinylestradiol (EE2) on tissue uptake of both contaminants in juvenile turbot (Scophthalmus maximus). Silver uptake and tissue distribution (gills, liver, kidney, stomach, muscle and bile) were analyzed following a 14-day, 2-h daily pulsed exposure to AgNPs (2 μg L(-1) and 200 μg L(-1)), Ag(+) (50 μg L(-1)), EE2 (50 ng L(-1)) and AgNP + EE2 (2 or 200 μg L(-1)+50 ng L(-1)). Effects of the exposures on plasma vitellogenin (Vtg) levels, EE2 and steroid hormone concentrations were investigated. The AgNP and AgNP + EE2 exposures resulted in similar Ag concentrations in the tissues, indicating that combined exposure did not influence Ag uptake in tissues. The highest Ag concentrations were found in gills. For the Ag(+) exposed fish, the highest Ag concentrations were measured in the liver. Our results show dissolution processes of AgNPs in seawater, indicating that the tissue concentrations of Ag may partly originate from ionic release. Plasma EE2 concentrations and Vtg induction were similar in fish exposed to the single contaminants and the mixed contaminants, indicating that the presence of AgNPs did not significantly alter EE2 uptake. Similarly, concentrations of most steroid hormones were not significantly altered due to exposures to the combined contaminants versus the single compound exposures. However, high concentrations of AgNPs in combination with EE2 caused a drop of estrone (E1) (female fish) and androstenedione (AN) (male and female fish) levels in plasma below quantification limits. Our results indicate that the interactive effects between AgNPs and EE2 are limited, with only high concentrations of AgNPs triggering

  9. Structural studies of a potent insect maturation inhibitor bound to the juvenile hormone esterase of Manduca sexta†‡

    PubMed Central

    Wogulis, Mark; Wheelock, Craig E.; Kamita, Shizuo G.; Hinton, Andrew C.; Whetstone, Paul A.; Hammock, Bruce D.; Wilson, David K.

    2008-01-01

    Juvenile hormone (JH) is an insect hormone containing an α,β unsaturated ester consisting of a small alcohol and long, hydrophobic acid. JH degradation is required for proper insect development. One pathway of this degradation is through juvenile hormone esterase (JHE), which cleaves the JH ester bond to produce methanol and JH acid. JHE is a member of the functionally divergent α/β-hydrolase family of enzymes, and is a highly efficient enzyme that cleaves JH at very low in vivo concentrations. We present here a 2.7 Å crystal structure of JHE from the tobacco hornworm Manduca sexta (MsJHE) in complex with the transition state analog inhibitor 3-octylthio-1,1,1-trifluoropropan-2-one (OTFP) covalently bound to the active site. This crystal structure, the first JHE structure reported, contains a long, hydrophobic binding pocket with the solvent inaccessible catalytic triad located at the end. The structure explains many of the interactions observed between JHE and its substrates and inhibitors, such as the preference for small alcohol groups and long hydrophobic backbones. The most potent JHE inhibitors identified to date contain a trifluoromethyl ketone (TFK) moiety and have a sulfur atom beta to the ketone. In this study, sulfur-aromatic interactions were observed between the sulfur atom of OTFP and a conserved aromatic residue in the crystal structure. Mutational analysis supported the hypothesis that these interactions contribute to the potency of sulfur-containing TFK inhibitors. Together these results clarify the binding mechanism of JHE inhibitors and provide useful observations for the development of additional enzyme inhibitors for a variety of enzymes. PMID:16566578

  10. Influence of female sex hormones on periodontium: A case series

    PubMed Central

    Jafri, Zeba; Bhardwaj, Ashu; Sawai, Madhuri; Sultan, Nishat

    2015-01-01

    Dental plaque is the primary etiologic factor for the periodontal diseases. Although pathogenic bacteria in dental plaque are necessary for the incidence of periodontal disease, but a susceptible host is as important. The susceptibility of the host can be modified by various systemic factors with hormones level being one. The periodontium shows an exaggerated inflammatory response to plaque modified by female sex hormone during puberty, pregnancy, in women taking oral contraceptives and at the postmenopausal stage. This paper presents such few cases where periodontium is influenced by variation in sex steroid hormones of female during different phases of their life time and to discuss how much a same hormone at different age and stage shows an exaggerated gingival response to plaque. PMID:26604605

  11. Factors influencing distribution of juvenile yellowtail flounder ( Limanda ferruginea) on the grand bank of Newfoundland

    NASA Astrophysics Data System (ADS)

    Walsh, S. J.

    On the Grand Bank, off the coast of Newfoundland, yellowtail flounder is at its northern limit in abundance. The population is relatively sedentary and has formed the basis of a traditional trawler fishery since the middle 1960s. However, very little is known about this species' early life history stages and ecology. Beginning in 1985, bottom trawl surveys have been conducted annually to determine distribution and abundance of juvenile yellowtail flounder on the Grand Bank. It was found that both juveniles and adults maintained their shallow water depth distribution despite wide fluctuations in temperature. Based on the analyses of the distribution of age-1 group and older juveniles (up to 4 years) and incorporating historical information on egg and larval surveys, physical oceanography and substrate type in the region it was found that all early life history stages were retained in the same geographic area, on and adjacent to the Southeast Shoal on the southern Grand Bank. It is suggested that passive retention of eggs and larvae is related to a weak current regime on the southern Grand Bank. Age-1 group and older juveniles were consistently found on a sandy substrate in the same area, indicating that sediment size is an important factor influencing distribution. These observed patterns of distribution of eggs, larvae, and juveniles points to the Southeast Shoal area as being an oceanic nursery site for Grand Bank yellowtail flounder. But unlike the well-published North Sea coastal nurseries, this oceanic nursery also contains newly settled juveniles, older juveniles, and adults.

  12. Effect of juvenile hormone analog, methoprene on H-fibroin regulation during the last instar larval development of Corcyra cephalonica.

    PubMed

    Chaitanya, R K; Sridevi, P; Senthilkumaran, B; Dutta Gupta, Aparna

    2013-01-15

    Juvenile hormone (JH) and 20-hydroxyecdysone (20E), co-ordinately orchestrate insect growth and development. The process of silk synthesis and secretion in lepidopteran insects is known to be under hormonal control. However, the role of JH in this process has not been demonstrated hitherto. The present study is aimed to elucidate the role of JH in H-fibroin regulation in Corcyra cephalonica, a serious lepidopteran pest. Reiterated amino acid stretches and the large molecular weight of H-fibroin render its cloning and characterization cumbersome. To address this, a commercially synthesized short amino acid peptide conjugated with a carrier protein was used to generate antibodies against the N-terminal region of H-fibroin. ELISA and immunoblot experiments demonstrated the sensitivity and specificity of antibody. Further, immunohistochemical analyses revealed the antibody's cross-reactivity with H-fibroins of C. cephalonica and Bombyx mori in the silk gland lumen. Quantitative RT-PCR and Western blot analysis demonstrated the tissue-specificity and developmental expression of H-fibroin. Hormonal studies revealed that JH alone does not alter the expression of H-fibroin. However, in the presence 20E, JH reverses the declined expression caused by 20E administration to normal levels. This study provides molecular evidence for the regulation of H-fibroin by the cumulative action of JH and 20E.

  13. Gender Differences in Cardiovascular Disease: Hormonal and Biochemical Influences

    PubMed Central

    Pérez-López, Faustino R.; Larrad-Mur, Luis; Kallen, Amanda; Chedraui, Peter; Taylor, Hugh S.

    2011-01-01

    Objective Atherosclerosis is a complex process characterized by an increase in vascular wall thickness owing to the accumulation of cells and extracellular matrix between the endothelium and the smooth muscle cell wall. There is evidence that females are at lower risk of developing cardiovascular disease (CVD) as compared to males. This has led to an interest in examining the contribution of genetic background and sex hormones to the development of CVD. The objective of this review is to provide an overview of factors, including those related to gender, that influence CVD. Methods Evidence analysis from PubMed and individual searches concerning biochemical and endocrine influences and gender differences, which affect the origin and development of CVD. Results Although still controversial, evidence suggests that hormones including estradiol and androgens are responsible for subtle cardiovascular changes long before the development of overt atherosclerosis. Conclusion Exposure to sex hormones throughout an individual's lifespan modulates many endocrine factors involved in atherosclerosis. PMID:20460551

  14. VARIATION IN GROWTH, LIPID CLASS AND FATTY ACID COMPOSITION OF THE MUD CRAB, RHITHROPANOPEUS HARRISII (GOULD) DURING LARVAL DEVELOPMENT FOLLOWING EXPOSURE TO AN INSECT JUVENILE HORMONE ANALOG (FENOXYCARB)

    EPA Science Inventory

    This study examines the effects of fenoxycarb?, an insect juvenile hormone analog, on larval growth, and lipid class and fatty acid composition in first crabs of the mud crab Rhithropanopeus harrisii reared through total larval development in nominal water concentrations from 1 ...

  15. Precocene-I inhibits juvenile hormone biosynthesis, ovarian activation, aggression and alters sterility signal production in bumble bee (Bombus terrestris) workers

    USDA-ARS?s Scientific Manuscript database

    Juvenile hormone (JH) is an important regulator of development and physiology in insects. While in many insect species, including bumble bees, JH function as gonadotropin in adults, in some highly eusocial insects its role has shifted to regulate social behavior including division of labor, dominanc...

  16. VARIATION IN GROWTH, LIPID CLASS AND FATTY ACID COMPOSITION OF THE MUD CRAB, RHITHROPANOPEUS HARRISII (GOULD) DURING LARVAL DEVELOPMENT FOLLOWING EXPOSURE TO AN INSECT JUVENILE HORMONE ANALOG (FENOXYCARB)

    EPA Science Inventory

    This study examines the effects of fenoxycarb?, an insect juvenile hormone analog, on larval growth, and lipid class and fatty acid composition in first crabs of the mud crab Rhithropanopeus harrisii reared through total larval development in nominal water concentrations from 1 ...

  17. The Influence of Direct and Indirect Juvenile Victimization Experiences on Adult Victimization and Fear of Crime.

    PubMed

    Grubb, Jonathan A; Bouffard, Leana A

    2015-11-01

    Research has identified that juvenile victimization can play a detrimental role for individuals later in life. While this literature has focused on direct and indirect forms of victimization at different stages of life, the influence of juvenile victimization on fear of crime and violent victimization as an adult has been limited. To expand this body of literature, the present research examines the effects of direct (sexual victimization) and indirect (witnessing parental intimate partner violence) juvenile victimization on fear of crime as well as the prevalence of victimization as an adult. Using telephone survey data collected from randomly selected Texas adults, this study demonstrates that both juvenile sexual victimization and indirect victimization increase the likelihood of adult victimization, whereas juvenile sexual victimization increases the likelihood of adult sexual victimization. In contrast, fear of crime as an adult was not significantly influenced by either juvenile sexual victimization or indirect victimization. A discussion of how these findings relate to previous research, limitations, and implications are also provided. © The Author(s) 2014.

  18. The Influence of Treatment Motivation on Outcomes of Social Skills Training for Juvenile Delinquents.

    PubMed

    van der Stouwe, Trudy; Asscher, Jessica J; Hoeve, Machteld; van der Laan, Peter H; Stams, Geert Jan J M

    2016-05-24

    This study examined the influence of treatment motivation on posttreatment effectiveness of an outpatient, individual social skills training for juvenile delinquents imposed as a penal sanction. Propensity score matching was used to match a control group of juveniles receiving treatment as usual (n = 108 of total N = 354) to a treatment group of juveniles receiving Tools4U, a social skills training with a parental component (N = 115). Treatment motivation was examined as a moderator and predictor of treatment effects on impulsivity, social perspective-taking, social problem-solving, lack of critical reasoning, developmental task-related skills, and parenting skills. Treatment effects were mostly consistent across juveniles with different levels of treatment motivation. Only one moderating effect was found on active tackling (i.e., actively addressing problems), and predictive effects were found on seeking social support, cognitive empathy, hostile intent attribution, and self-centeredness. Implications for further research are discussed. © The Author(s) 2016.

  19. Tissue localization and regulation by juvenile hormone of human allergen Bla g 4 from the German cockroach, Blattella germanica (L.).

    PubMed

    Fan, Y; Gore, J C; Redding, K O; Vailes, L D; Chapman, M D; Schal, C

    2005-01-01

    The German cockroach, Blattella germanica (L.), produces several potent protein aeroallergens, including Bla g 4, a approximately 20 kDa lipocalin. RT-PCR, Northern analyses and in situ hybridization showed that Bla g 4 is expressed only in the adult male reproductive system. Western blotting and ELISA with rBla g 4 antiserum detected immunoreactivity in the utricles and the conglobate gland, but not in other tissues of the male reproductive system. The Bla g 4 protein content of males increased from adult emergence to day 14, but during copulation Bla g 4 was depleted in the male and transferred to the female within the spermatophore. Topical application of juvenile hormone III stimulated Bla g 4 production by both conglobate gland and utricles.

  20. Juvenile Hormone Analogues, Methoprene and Fenoxycarb Dose-Dependently Enhance Certain Enzyme Activities in the Silkworm Bombyx Mori (L)

    PubMed Central

    Mamatha, Devi M.; Kanji, Vijaya K.; Cohly, Hari H.P.; Rao, M. Rajeswara

    2008-01-01

    Use of Juvenile Hormone Analogues (JHA) in sericulture practices has been shown to boost good cocoon yield; their effect has been determined to be dose-dependent. We studied the impact of low doses of JHA compounds such as methoprene and fenoxycarb on selected key enzymatic activities of the silkworm Bombyx mori. Methoprene and fenoxycarb at doses of 1.0 μg and 3.0fg/larvae/48 hours showed enhancement of the 5th instar B. mori larval muscle and silkgland protease, aspartate aminotransaminase (AAT) and alanine aminotransaminase (ALAT), adenosine triphosphate synthase (ATPase) and cytochrome-c-oxidase (CCO) activity levels, indicating an upsurge in the overall oxidative metabolism of the B.mori larval tissues. PMID:18678927

  1. Juvenile Hormone Analogues, methoprene and fenoxycarb dose-dependently enhance certain enzyme activities in the silkworm Bombyx mori (L).

    PubMed

    Mamatha, Devi M; Kanji, Vijaya K; Cohly, Hari H P; Rao, M Rajeswara

    2008-06-01

    Use of Juvenile Hormone Analogues (JHA) in sericulture practices has been shown to boost good cocoon yield; their effect has been determined to be dose-dependent. We studied the impact of low doses of JHA compounds such as methoprene and fenoxycarb on selected key enzymatic activities of the silkworm Bombyx mori. Methoprene and fenoxycarb at doses of 1.0 microg and 3.0 fg/larvae/48 hours showed enhancement of the 5th instar B. mori larval muscle and silkgland protease, aspartate aminotransaminase (AAT) and alanine aminotransaminase (ALAT), adenosine triphosphate synthase (ATPase) and cytochrome-c-oxidase (CCO) activity levels, indicating an upsurge in the overall oxidative metabolism of the B.mori larval tissues.

  2. Juvenile hormone stimulated tyrosine kinase-mediated protein phosphorylation in the CNS of the silk worm, Bombyx mori.

    PubMed

    Arif, A; Shanavas, A; Murthy, Ch R K; Dutta-Gupta, Aparna

    2002-07-01

    In vitro studies with the larval CNS of the silkworm, Bombyx mori revealed the phosphorylation of a 48-kDa protein, which was not dependent on cyclic nucleotides. Studies also revealed modest phosphorylation of this protein by a calcium-dependent but calmodulin-independent mechanism. However, phosphorylation of this protein was greatly enhanced in the presence of juvenile hormone (JH) I by a calcium-independent mechanism. This stimulatory effect of JH was seen in both homogenates as well as in intact CNS of Bombyx. Immunoblotting studies revealed the cross-reaction of this 48-kDa protein with phosphotyrosine monoclonal antibody and the phosphorylation of this protein was inhibited by genistein. This study suggests that the 48-kDa protein is a substrate for tyrosine kinase. The phosphorylation of this protein was also observed in other larval tissues such as salivary gland, fat body, and epidermis of Bombyx.

  3. [Role of DopR in the molecular mechanism of the dopamine control of juvenile hormone metabolism in female Drosophila].

    PubMed

    Karpova, E K; Bogomolova, E V; Romonova, I V; Gruntenko, N E; Raushenbakh, I Iu

    2012-08-01

    The effect of a decreased availability of the D1-like dopamine receptor (DopR) in Drosophila (caused by DopR antagonist added into food) on the juvenile hormone (JH) synthesis rate in young female D. melanogaster has been studied. The JH degradation rate and the alkaline phosphatase (ALP) and tyrosine decarboxylase (TDC) activities were used as indicators of the JH synthesis rate. Treatment of the flies with butaclamol, a specific DopR antagonist, has been demonstrated to increase the JH degradation rate, and the stress reactivity of the system of JH metabolism and decrease the ALP activity and stress reactivity, and increase the TDC activity and stress reactivity. As shown earlier, all this indicates a decrease in the JH synthesis rate in young female drosophila with a decreased DopR availability. It is concluded that the activating effect of dopamine on JH synthesis in Drosophila is mediated by D1-like receptors.

  4. Farnesol-like endogenous sesquiterpenoids in vertebrates: the probable but overlooked functional "inbrome" anti-aging counterpart of juvenile hormone of insects?

    PubMed

    De Loof, Arnold; Marchal, Elisabeth; Rivera-Perez, Crisalejandra; Noriega, Fernando G; Schoofs, Liliane

    2014-01-01

    Literature on the question whether the juvenile stage of vertebrates is hormonally regulated is scarce. It seems to be intuitively assumed that this stage of development is automated, and does not require any specific hormone(s). Such reasoning mimics the state of affairs in insects until it was shown that surgical removal of a tiny pair of glands in the head, the corpora allata, ended larval life and initiated metamorphosis. Decades later, the responsible hormone was found and named "juvenile hormone" (JH) because when present, it makes a larva molt into another larval stage. JH is a simple ester of farnesol, a sesquiterpenoid present in all eukaryotes. Whereas vertebrates do not have an anatomical counterpart of the corpora allata, their tissues do contain farnesol-like sesquiterpenoids (FLS). Some display typical JH activity when tested in appropriate insect bioassays. Some FLS are intermediates in the biosynthetic pathway of cholesterol, a compound that insects and nematodes (=Ecdysozoa) cannot synthesize by themselves. They ingest it as a vitamin. Until a recent (2014) reexamination of the basic principle underlying insect metamorphosis, it had been completely overlooked that the Ca(2+)-pump (SERCA) blocker thapsigargin is a sesquiterpenoid that mimics the absence of JH in inducing apoptosis. In our opinion, being in the juvenile state is primarily controlled by endogenous FLS that participate in controlling the activity of Ca(2+)-ATPases in the sarco(endo)plasmic reticulum (SERCAs), not only in insects but in all eukaryotes. Understanding the control mechanisms of being in the juvenile state may boost research not only in developmental biology in general, but also in diseases that develop after the juvenile stage, e.g., Alzheimer's disease. It may also help to better understand some of the causes of obesity, a syndrome that holometabolous last larval insects severely suffer from, and for which they found a very drastic but efficient solution, namely

  5. PCBs and DDT in the serum of juvenile California sea lions: associations with vitamins A and E and thyroid hormones.

    PubMed

    Debier, Cathy; Ylitalo, Gina M; Weise, Michael; Gulland, Frances; Costa, Daniel P; Le Boeuf, Burney J; de Tillesse, Tanguy; Larondelle, Yvan

    2005-03-01

    Top-trophic predators like California sea lions bioaccumulate high levels of persistent fat-soluble pollutants that may provoke physiological impairments such as endocrine or vitamins A and E disruption. We measured circulating levels of polychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethane (DDT) in 12 healthy juvenile California sea lions captured on Año Nuevo Island, California, in 2002. We investigated the relationship between the contamination by PCBs and DDT and the circulating levels of vitamins A and E and thyroid hormones (thyroxine, T4 and triiodothyronine, T3). Serum concentrations of total PCBs (sigmaPCBs) and total DDT were 14 +/- 9 mg/kg and 28 +/- 19 mg/kg lipid weight, respectively. PCB toxic equivalents (sigmaPCB TEQs) were 320 +/- 170 ng/kg lipid weight. Concentrations of sigmaPCBs and sigmaPCB TEQs in serum lipids were negatively correlated (p < 0.05) with serum vitamin A and T3, potentially reflecting PCB-related toxicity. A slight but not significant negative correlation (p < 0.1) was observed between serum T4 and the levels of sigmaPCBs and sigmaPCB TEQs. Conversely, no relationship was evident between the contaminant concentrations and vitamin E (p > 0.1). As juvenile California sea lions are useful sentinels of coastal contamination, the high levels encountered in their serum is cause for concern about the ecosystem health of the area.

  6. Lipophorin of female Blattella germanica (L.): characterization and relation to hemolymph titers of juvenile hormone and hydrocarbons.

    PubMed

    Sevala, V; Shu, S; Ramaswamy, S B.; Schal, C

    1999-05-01

    High density lipophorin (HDLp) from the hemolymph of the German cockroach, Blattella germanica (L.) (Family Blattellidae), has an apparent molecular weight of 670kDa, with an isoelectric point of 7.0 and a density of 1.109g/ml. It is composed of two subunits, apolipoprotein-I (212kDa) and apolipoprotein-II (80kDa), and consists of 51.4% lipid, 46.2% protein and 2.4% carbohydrate. Hydrocarbons constitute 42.2% of the total lipids which also contain diacylglycerol, cholesterol and phospholipid. Lipophorin is rich in the amino acids glutamic acid, aspartic acid, lysine, valine, and leucine. Specificity of a polyclonal antibody was demonstrated by Western blotting and Ouchterlony immunodiffusion: the antiserum recognized native HDLp and apolipoprotein-I, but not apolipoprotein-II, purified vitellin, or other hemolymph proteins. It also recognized a protein in the hemolymph of Supella longipalpa (Blattellidae) but did not cross-react with hemolymph proteins from Periplaneta americana (Blattidae) or Diploptera punctata (Blaberidae). An enzyme-linked immunosorbent assay was developed to measure the HDLp titer in the hemolymph of adult females. The titer of HDLp, a juvenile hormone binding protein, exhibited no clear relationship to the changing titer of juvenile hormone in hemolymph. The hemolymph titer of hydrocarbon, which is also carried by HDLp, showed some functional relation to the concentration of HDLp in the hemolymph. Because it concurrently serves multiple functions in insect development and reproduction, lipophorin titer might covary with the titers of lipid ligands that occur at high concentrations and require extensive shuttling through the hemolymph.

  7. Hormonal influences on neuroimmune responses in the CNS of females

    PubMed Central

    Monasterio, Nela; Vergara, Edgar; Morales, Teresa

    2014-01-01

    Particular reproductive stages such as lactation impose demands on the female. To cope with these demands, her physiology goes through numerous adaptations, for example, attenuation of immune and stress responses. Hormonal fluctuation during lactation exerts a strong influence, inducing neuroplasticity in the hypothalamus and extrahypothalamic regions, and diminishing the stress and inflammatory responses. Thus, hormones confer decreased vulnerability to the female brain. This mini-review focuses on the adaptations of the immune and stress response during maternity, and on the neuroprotective actions of progesterone and prolactin and their effects on inflammation. The importance of pregnancy and lactation as experimental models to study immune responses and disease is also highlighted. PMID:24478642

  8. SEX DIFFERENCES AND REPRODUCTIVE HORMONE INFLUENCES ON HUMAN ODOR PERCEPTION

    PubMed Central

    Doty, Richard L.; Cameron, E. Leslie

    2009-01-01

    The question of whether men and women differ in their ability to smell has been the topic of scientific investigation for over a hundred years. Although conflicting findings abound, most studies suggest that, for at least some odorants, women outperform men on tests of odor detection, identification, discrimination, and memory. Most functional imaging and electrophysiological studies similarly imply that, when sex differences are present, they favor women. In this review we examine what is known about sex-related alterations in human smell function, including influences of the menstrual cycle, pregnancy, gonadectomy, and hormone replacement therapy on a range of olfactory measures. We conclude that the relationship between reproductive hormones and human olfactory function is complex and that simple associations between circulating levels of gonadal hormones and measures of olfactory function are rarely present. PMID:19272398

  9. [How corticoids, growth hormone and oestrogens influence lipids and atherosclerosis].

    PubMed

    Marek, J; Hána, V; Krsek, M

    2007-04-01

    The hormones with a strong influence on the lipid spectrum and the development of atherosclerosis include cortisol, growth hormone and oestrogens. Cortisol accelerates atherosclerosis both through dyslipidemia and through an increase in visceral fat, hypertension, increased insulin resistance and the development of reduced glucose tolerance which may result in diabetes mellitus. Even when a cortisol excess disappears, as is the case of patients cured of Cushing syndrome, arterial walls remain permanently vulnerable to the atherosclerotic process. In conditions involving a lack of growth hormone, dyslipidemia develops and increases the burden on the cardiovascular system if not treated in a timely manner by the substitution of growth hormone. Oestrogens have a double effect: they have an anti-atherogenic effect on artery walls that are not yet damaged by an atherosclerotic process, but where atherosclerosis has already developed they have a prothrombotic effect and destabilise the atheromatous plaques. If oestrogen is to be used as protection against the onset of atherogenesis, it is necessary to start in a period when the atherosclerotic process has not yet begun to damage the woman's arterial walls and it is best to use natural hormones (estradiol) and to prevent endometriosis it should be combined with crystalline progesterone applied locally--inravaginally. Oestrogens should be given in small doses, preferably parenterally. Even this will not prevent genetic oestrogen effects though.

  10. Influence of food availability on the spatial distribution of juvenile fish within soft sediment nursery habitats

    NASA Astrophysics Data System (ADS)

    Tableau, A.; Brind'Amour, A.; Woillez, M.; Le Bris, H.

    2016-05-01

    Soft sediments in coastal shallow waters constitute nursery habitats for juveniles of several flatfishes. The quality of a nursery is defined by its capacity to optimize the growth and the survival of juvenile fish. The influence of biotic factors, such as food availability, is poorly studied at the scale of a nursery ground. Whether food availability limits juvenile survival is still uncertain. A spatial approach is used to understand the influence of food availability on the distribution of juvenile fish of various benthic and demersal species in the Bay of Vilaine (France), a productive nursery ground. We quantified the spatial overlap between benthic macro-invertebrates and their predators (juvenile fish) to assess if the latter were spatially covering the most productive areas of the Bay. Three scenarios describing the shapes of the predator-prey spatial relationship were tested to quantify the strength of the relationship and consequently the importance of food availability in determining fish distribution. Our results underline that both food availability and fish densities vary greatly over the nursery ground. When considering small organisational levels (e.g., a single fish species), the predator-prey spatial relationship was not clear, likely because of additional environmental effects not identified here; but at larger organisational level (the whole juvenile fish community), a strong overlap between the fish predators and their prey was identified. The evidence that fish concentrate in sectors with high food availability suggests that either food is the limiting factor in that nursery or/and fish display behavioural responses by optimising their energetic expenditures associated with foraging. Further investigations are needed to test the two hypotheses and to assess the impact of benthic and demersal juvenile fish in the food web of coastal nurseries.

  11. Pleiotropic effects of juvenile hormone in ant queens and the escape from the reproduction–immunocompetence trade-off

    PubMed Central

    Pamminger, Tobias; Treanor, David; Hughes, William O. H.

    2016-01-01

    The ubiquitous trade-off between survival and costly reproduction is one of the most fundamental constraints governing life-history evolution. In numerous animals, gonadotropic hormones antagonistically suppressing immunocompetence cause this trade-off. The queens of many social insects defy the reproduction–survival trade-off, achieving both an extraordinarily long life and high reproductive output, but how they achieve this is unknown. Here we show experimentally, by integrating quantification of gene expression, physiology and behaviour, that the long-lived queens of the ant Lasius niger have escaped the reproduction–immunocompetence trade-off by decoupling the effects of a key endocrine regulator of fertility and immunocompetence in solitary insects, juvenile hormone (JH). This modification of the regulatory architecture enables queens to sustain a high reproductive output without elevated JH titres and suppressed immunocompetence, providing an escape from the reproduction–immunocompetence trade-off that may contribute to the extraordinary lifespan of many social insect queens. PMID:26763704

  12. A cumulative feeding threshold required for vitellogenesis can be obviated with juvenile hormone treatment in lubber grasshoppers.

    PubMed

    Fronstin, R B; Hatle, J D

    2008-01-01

    Developmental thresholds can ensure that an adequate condition has been attained to proceed through major transitions (e.g. initiation of reproduction, metamorphosis). Nutrition is critical to attaining most thresholds, because it is needed for both growth and storage. Attaining a threshold typically stimulates the release of hormones that commit the animal to the developmental transition, yet the relationships between the nutrition needed for developmental thresholds and these endocrine signals are poorly understood. Lubber grasshoppers require a cumulative feeding threshold to initiate vitellogenesis and potentially commit to oviposition. We tested the relative roles of the nutritional threshold and the major gonadotropin (juvenile hormone; JH) in initiating vitellogenesis and committing to oviposition. The source of JH was removed from all females, and then JH analog was applied after different amounts of feeding. Threshold feeding was not required to initiate vitellogenesis, suggesting that sub-threshold grasshoppers are competent to respond to JH. Further, sub-threshold grasshoppers went on to oviposit earlier than supra-threshold grasshoppers treated with JH at the same time. Hence, threshold feeding is required only to cause the production and release of JH. At the same time, we also found that individuals that were restored with JH late in life tended to favor current reproduction, at the expense of future reproduction. Both time to oviposition and vitellogenin profiles were consistent with this developmental allocation. Taken together, our results suggest that lubber grasshoppers adjust reproductive tactics primarily in response to nutrition (which only serves to release JH) and secondarily in response to age.

  13. Juvenile Hormone Prevents 20-Hydroxyecdysone-induced Metamorphosis by Regulating the Phosphorylation of a Newly Identified Broad Protein*

    PubMed Central

    Cai, Mei-Juan; Liu, Wen; Pei, Xu-Yang; Li, Xiang-Ru; He, Hong-Juan; Wang, Jin-Xing; Zhao, Xiao-Fan

    2014-01-01

    The steroid hormone 20-hydroxyecdysone (20E) initiates insect molting and metamorphosis. By contrast, juvenile hormone (JH) prevents metamorphosis. However, the mechanism by which JH inhibits metamorphosis remains unclear. In this study, we propose that JH induces the phosphorylation of Broad isoform Z7 (BrZ7), a newly identified protein, to inhibit 20E-mediated metamorphosis in the lepidopteran insect Helicoverpa armigera. The knockdown of BrZ7 in larvae inhibited metamorphosis by repressing the expression of the 20E response gene. BrZ7 was weakly expressed and phosphorylated during larval growth but highly expressed and non-phosphorylated during metamorphosis. JH regulated the rapid phosphorylation of BrZ7 via a G-protein-coupled receptor-, phospholipase C-, and protein kinase C-triggered pathway. The phosphorylated BrZ7 bound to the 5′-regulatory region of calponin to regulate its expression in the JH pathway. Exogenous JH induced BrZ7 phosphorylation to prevent metamorphosis by suppressing 20E-related gene transcription. JH promoted non-phosphorylated calponin interacting with ultraspiracle protein to activate the JH pathway and antagonize the 20E pathway. This study reveals one of the possible mechanisms by which JH counteracts 20E-regulated metamorphosis by inducing the phosphorylation of BrZ7. PMID:25096576

  14. Juvenile hormone prevents 20-hydroxyecdysone-induced metamorphosis by regulating the phosphorylation of a newly identified broad protein.

    PubMed

    Cai, Mei-Juan; Liu, Wen; Pei, Xu-Yang; Li, Xiang-Ru; He, Hong-Juan; Wang, Jin-Xing; Zhao, Xiao-Fan

    2014-09-19

    The steroid hormone 20-hydroxyecdysone (20E) initiates insect molting and metamorphosis. By contrast, juvenile hormone (JH) prevents metamorphosis. However, the mechanism by which JH inhibits metamorphosis remains unclear. In this study, we propose that JH induces the phosphorylation of Broad isoform Z7 (BrZ7), a newly identified protein, to inhibit 20E-mediated metamorphosis in the lepidopteran insect Helicoverpa armigera. The knockdown of BrZ7 in larvae inhibited metamorphosis by repressing the expression of the 20E response gene. BrZ7 was weakly expressed and phosphorylated during larval growth but highly expressed and non-phosphorylated during metamorphosis. JH regulated the rapid phosphorylation of BrZ7 via a G-protein-coupled receptor-, phospholipase C-, and protein kinase C-triggered pathway. The phosphorylated BrZ7 bound to the 5'-regulatory region of calponin to regulate its expression in the JH pathway. Exogenous JH induced BrZ7 phosphorylation to prevent metamorphosis by suppressing 20E-related gene transcription. JH promoted non-phosphorylated calponin interacting with ultraspiracle protein to activate the JH pathway and antagonize the 20E pathway. This study reveals one of the possible mechanisms by which JH counteracts 20E-regulated metamorphosis by inducing the phosphorylation of BrZ7. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  15. Factors Influencing Emergence of Juveniles from Cysts of Heterodera zeae

    PubMed Central

    Hashmi, Sarwar; Krusberg, Lorin R.

    1995-01-01

    Several factors were studied to determine their effects on hatch and emergence of second-stage juveniles (J2) from cysts of Heterodera zeae. The optimum temperature for emergence of J2 from cysts of H. zeae was 30 C. No juveniles emerged from cysts at 10 or 40 C. Immersion of cysts in 4 mM zinc chloride solution stimulated 10% greater emergence of J2 than occurred in tap water controls during 28 days. Fresh corn rhizosphere leachates from 25-day and older plants growing in sand or sandy field soil stimulated 22-24% greater emergence of J2 from cysts than occurred in tap water after 28 days. Rhizosphere leachates stored for 30 days at 4 C and leachates of sand, sandy field soil, and silty field soil inhibited emergence of J2 from cysts by 7-12% compared to tap water. Rhizosphere leachates from corn plants aged 20, 30, 40, 50, or 60 days growing in sandy field soil stimulated emergence of J2 from cysts. Similar numbers of J2 emerged from cysts regardless of whether the source of cysts was field microplot cultures, greenhouse cultures, or growth chamber cultures. Fertilizing growth chamber cultures of H. zeae on corn plants resulted in a doubling of the numbers of cysts produced in the cultures, and those cysts yielded 2-3 times as many emerged J2 in hatching tests compared to cysts from similar unfertilized cultures. PMID:19277300

  16. Farnesol-Like Endogenous Sesquiterpenoids in Vertebrates: The Probable but Overlooked Functional “Inbrome” Anti-Aging Counterpart of Juvenile Hormone of Insects?

    PubMed Central

    De Loof, Arnold; Marchal, Elisabeth; Rivera-Perez, Crisalejandra; Noriega, Fernando G.; Schoofs, Liliane

    2014-01-01

    Literature on the question whether the juvenile stage of vertebrates is hormonally regulated is scarce. It seems to be intuitively assumed that this stage of development is automated, and does not require any specific hormone(s). Such reasoning mimics the state of affairs in insects until it was shown that surgical removal of a tiny pair of glands in the head, the corpora allata, ended larval life and initiated metamorphosis. Decades later, the responsible hormone was found and named “juvenile hormone” (JH) because when present, it makes a larva molt into another larval stage. JH is a simple ester of farnesol, a sesquiterpenoid present in all eukaryotes. Whereas vertebrates do not have an anatomical counterpart of the corpora allata, their tissues do contain farnesol-like sesquiterpenoids (FLS). Some display typical JH activity when tested in appropriate insect bioassays. Some FLS are intermediates in the biosynthetic pathway of cholesterol, a compound that insects and nematodes (=Ecdysozoa) cannot synthesize by themselves. They ingest it as a vitamin. Until a recent (2014) reexamination of the basic principle underlying insect metamorphosis, it had been completely overlooked that the Ca2+-pump (SERCA) blocker thapsigargin is a sesquiterpenoid that mimics the absence of JH in inducing apoptosis. In our opinion, being in the juvenile state is primarily controlled by endogenous FLS that participate in controlling the activity of Ca2+-ATPases in the sarco(endo)plasmic reticulum (SERCAs), not only in insects but in all eukaryotes. Understanding the control mechanisms of being in the juvenile state may boost research not only in developmental biology in general, but also in diseases that develop after the juvenile stage, e.g., Alzheimer’s disease. It may also help to better understand some of the causes of obesity, a syndrome that holometabolous last larval insects severely suffer from, and for which they found a very drastic but efficient solution, namely

  17. The FOXO transcription factor controls insect growth and development by regulating juvenile hormone degradation in the silkworm, Bombyx mori.

    PubMed

    Zeng, Baosheng; Huang, Yuping; Xu, Jun; Shiotsuki, Takahiro; Bai, Hua; Palli, Subba Reddy; Huang, Yongping; Tan, Anjiang

    2017-07-14

    Forkhead box O (FOXO) functions as the terminal transcription factor of the insulin signaling pathway and regulates multiple physiological processes in many organisms, including lifespan in insects. However, how FOXO interacts with hormone signaling to modulate insect growth and development is largely unknown. Here, using the transgene-based CRISPR/Cas9 system, we generated and characterized mutants of the silkworm Bombyx mori FOXO (BmFOXO) to elucidate its physiological functions during development of this lepidopteran insect. The BmFOXO mutant (FOXO-M) exhibited growth delays from the first larval stage and showed precocious metamorphosis, pupating at the end of the fourth instar (trimolter) rather than at the end of the fifth instar as in the wild-type (WT) animals. However, different from previous reports on precocious metamorphosis caused by juvenile hormone (JH) deficiency in silkworm mutants, the total developmental time of the larval period in the FOXO-M was comparable with that of the WT. Exogenous application of 20-hydroxyecdysone (20E) or of the JH analog rescued the trimolter phenotype. RNA-seq and gene expression analyses indicated that genes involved in JH degradation but not in JH biosynthesis were up-regulated in the FOXO-M compared with the WT animals. Moreover, we identified several FOXO-binding sites in the promoter of genes coding for JH-degradation enzymes. These results suggest that FOXO regulates JH degradation rather than its biosynthesis, which further modulates hormone homeostasis to control growth and development in B. mori In conclusion, we have uncovered a pivotal role for FOXO in regulating JH signaling to control insect development. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  18. The fate of follicles after a blood meal is dependent on previtellogenic nutrition and juvenile hormone in Aedes aegypti.

    PubMed

    Clifton, Mark E; Noriega, Fernando G

    2012-07-01

    Juvenile hormone (JH) mediates the relationship between fecundity and nutrition during the gonotrophic cycle of the mosquito in three ways: (1) by regulating initial previtellogenic development, (2) by mediating previtellogenic resorption of follicles and (3) by altering intrinsic previtellogenic follicle "quality", physiology, and competitiveness thereby predetermining the fate of follicles after a blood meal. To support a role for JH in mediating the response of ovarian follicles after a blood meal, we explored three main questions: (1) Do changes in nutrition during the previtellogenic resting stage lead to relevant biochemical and molecular changes in the previtellogenic ovary? (2) Do hormonal manipulations during the previtellogenic resting stage lead to the same biochemical and molecular changes? (3) Does nutrition and hormones during the previtellogenic resting stage affect vitellogenic resorption and reproductive output? We examined the accumulation of neutral lipids in the previtellogenic ovary as well as the previtellogenic expression of genes integral to endocytosis and oocyte development such as the: vitellogenin receptor (AaVgR), lipophorin receptor (AaLpRov), heavy-chain clathrin (AaCHC), and ribosomal protein L32 (rpL32) under various previtellogenic nutritional and hormonal conditions. mRNA abundance and neutral lipid content increased within the previtellogenic ovary as previtellogenic mosquitoes were offered increasing sucrose concentrations. Methoprene application mimicked the effect of offering the highest sucrose concentrations on mRNA abundance and lipid accumulation in the previtellogenic ovary. These same nutritional and hormonal manipulations altered the extent of vitellogenic resorption. Mosquitoes offered 20% sucrose during the previtellogenic resting stage had nearly 3 times less vitellogenic resorption than mosquitoes offered 3% sucrose despite taking smaller blood meals and developed ∼10% more eggs during the first gonotrophic cycle

  19. No effect of juvenile hormone on task performance in a bumblebee (Bombus terrestris) supports an evolutionary link between endocrine signaling and social complexity.

    PubMed

    Shpigler, Hagai Y; Siegel, Adam J; Huang, Zachary Y; Bloch, Guy

    2016-09-01

    A hallmark of insect societies is a division of labor among workers specializing in different tasks. In bumblebees the division of labor is related to body size; relatively small workers are more likely to stay inside the nest and tend ("nurse") brood, whereas their larger sisters are more likely to forage. Despite their ecological and economic importance, very little is known about the endocrine regulation of division of labor in bumblebees. We studied the influence of juvenile hormone (JH) on task performance in the bumblebee Bombus terrestris. We first used a radioimmunoassay to measure circulating JH titers in workers specializing in nursing and foraging activities. Next, we developed new protocols for manipulating JH titers by combining a size-adjusted topical treatment with the allatotoxin Precocene-I and replacement therapy with JH-III. Finally, we used this protocol to test the influence of JH on task performance. JH levels were either similar for nurses and foragers (three colonies), or higher in nurses (two colonies). Nurses had better developed ovaries and JH levels were typically positively correlated with ovarian state. Manipulation of JH titers influenced ovarian development and wax secretion, consistent with earlier allatectomy studies. These manipulations however, did not affect nursing or foraging activity, or the likelihood to specialize in nursing or foraging activity. These findings contrast with honeybees in which JH influences age-related division of labor but not adult female fertility. Thus, the evolution of complex societies in bees was associated with modifications in the way JH influences social behavior. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Ecdysteroids, juvenile hormone and insect neuropeptides: Recent successes and remaining major challenges.

    PubMed

    De Loof, Arnold

    2008-01-01

    In the recent decade, tremendous progress has been realized in insect endocrinology as the result of the application of a variety of advanced methods in neuropeptidome- and receptor research. Hormones of which the existence had been shown by bioassays four decades ago, e.g. bursicon (a member of the glycoprotein hormone family) and pupariation factor (Neb-pyrokinin 2, a myotropin), could be identified, along with their respective receptors. In control of diurnal rhythms, clock genes got company from the neuropeptide Pigment Dispersing Factor (PDF), of which the receptor could also be identified. The discovery of Inka cells and their function in metamorphosis was a true hallmark. Analysis of the genomes of Caenorhabditis elegans, Drosophila melanogaster and Apis mellifera yielded about 75, 100 and 200 genes coding for putative signaling peptides, respectively, corresponding to approximately 57, 100 and 100 peptides of which the expression could already be proven by means of mass spectrometry. The comparative approach invertebrates-vertebrates recently yielded indications for the existence of counterparts in insects for prolactin, atrial natriuretic hormone and Growth Hormone Releasing Hormone (GRH). Substantial progress has been realized in identifying the Halloween genes, a membrane receptor(s) for ecdysteroids, a nuclear receptor for methylfarnesoate, and dozens of GPCRs for insect neuropeptides. The major remaining challenges concern the making match numerous orphan GPCRs with orphan peptidic ligands, and elucidating their functions. Furthermore, the endocrine control of growth, feeding-digestion, and of sexual differentiation, in particular of males, is still poorly understood. The finding that the prothoracic glands produce an autocrine factor with growth factor-like properties and secrete proteins necessitates a reevaluation of their role in development.

  1. Influence of hormones and hormone antagonists on sexual differentiation of the brain.

    PubMed

    Döhler, K D

    1998-01-01

    In summary, a number of studies have shown that not only estrogenic and androgenic steroids and their antagonists influence sexual differentiation of the mammalian brain but also drugs which stimulate or inhibit the adrenergic, the serotoninergic, or the cholinergic system in the developing brain. The present knowledge on the possible participation of neurotransmitter systems in sexual differentiation of the brain and their mode of interaction in this process perinatally with gonadal steroids is still rather limited. Sexual differentiation of the central nervous system is a complex integrated process, which relies on proper chronological and quantitative interactions of various endocrine and neuroendocrine mediators. Any disturbance of this delicate endogenous hormonal balance during ontogenetic development, e.g. by means of environmental influences, can result in permanent manifestation of anatomic and functional sexual deviations. A large number of man-made chemicals that have been released into the environment have the potential to disrupt the endocrine system of animals and humans. They do so because they mimick the effects of natural hormones or neurotransmitters by recognizing their binding sites, or they antagonize the effects of endogenous hormones or neurotransmitters by blocking their interaction with their physiological binding sites. Interaction of environmental endocrine disruptors with animals or humans during ontogeny may have deleterious effects on the differentiation of reproductive structures and functions, rendering the individuals in question permanently incapable to reproduce and, thus, endangering survival of the species.

  2. Hormonal Influence on Coenzyme Q10 Levels in Blood Plasma

    PubMed Central

    Mancini, Antonio; Festa, Roberto; Raimondo, Sebastiano; Pontecorvi, Alfredo; Littarru, Gian Paolo

    2011-01-01

    Coenzyme Q10 (CoQ10), also known as ubiquinone for its presence in all body cells, is an essential part of the cell energy-producing system. However, it is also a powerful lipophilic antioxidant protecting lipoproteins and cell membranes. Due to these two actions, CoQ10 is commonly used in clinical practice in chronic heart failure, male infertility, and neurodegenerative disease. However, it is also taken as an anti-aging substance by healthy people aiming for long-term neuroprotection and by sportsmen to improve endurance. Many hormones are known to be involved in body energy regulation, in terms of production, consumption and dissipation, and their influence on CoQ10 body content or blood values may represent an important pathophysiological mechanism. We summarize the main findings of the literature about the link between hormonal systems and circulating CoQ10 levels. In particular the role of thyroid hormones, directly involved in the regulation of energy homeostasis, is discussed. There is also a link with gonadal and adrenal hormones, partially due to the common biosynthetic pathway with CoQ10, but also to the increased oxidative stress found in hypogonadism and hypoadrenalism. PMID:22272129

  3. Examining the Influence of Ethnic/Racial Socialization on Aggressive Behaviors Among Juvenile Offenders

    PubMed Central

    Zapolski, Tamika C. B.; Garcia, Crystal A.; Jarjoura, G. Roger; Lau, Katherine S. L.; Aalsma, Matthew C.

    2016-01-01

    Risk assessment instruments are commonly used within the juvenile justice system to estimate a juvenile's likelihood of reoffending or engaging in aggressive or violent behavior. Although such instruments assess a broad range of factors, the influence of culture is often excluded. The current study examines the unique effect of ethnic/racial socialization on recent aggressive behaviors above and beyond three well-established risk and protective factors: delinquency history, moral disengagement, and social support. Participants were 95 juveniles who were either on probation or in detention centers in three Midwestern counties and who completed structured surveys related to personal experiences within and outside of the juvenile justice system. The findings provided partial support for our hypotheses: Consistent with previous findings, delinquency history and moral disengagement were significant predictors of recent aggressive behavior. Furthermore, when ethnic/racial socialization was added to the model, promotion of mistrust provided additional predictive validity for aggressive behavior above and beyond the other factors assessed. Based on these findings, the inclusion of education on culture may prove to be an important supplement to established intervention tools for juvenile offenders. PMID:27453798

  4. Examining the Influence of Ethnic/Racial Socialization on Aggressive Behaviors Among Juvenile Offenders.

    PubMed

    Zapolski, Tamika C B; Garcia, Crystal A; Jarjoura, G Roger; Lau, Katherine S L; Aalsma, Matthew C

    2016-01-01

    Risk assessment instruments are commonly used within the juvenile justice system to estimate a juvenile's likelihood of reoffending or engaging in aggressive or violent behavior. Although such instruments assess a broad range of factors, the influence of culture is often excluded. The current study examines the unique effect of ethnic/racial socialization on recent aggressive behaviors above and beyond three well-established risk and protective factors: delinquency history, moral disengagement, and social support. Participants were 95 juveniles who were either on probation or in detention centers in three Midwestern counties and who completed structured surveys related to personal experiences within and outside of the juvenile justice system. The findings provided partial support for our hypotheses: Consistent with previous findings, delinquency history and moral disengagement were significant predictors of recent aggressive behavior. Furthermore, when ethnic/racial socialization was added to the model, promotion of mistrust provided additional predictive validity for aggressive behavior above and beyond the other factors assessed. Based on these findings, the inclusion of education on culture may prove to be an important supplement to established intervention tools for juvenile offenders.

  5. Influences of neighborhood context, individual history and parenting behavior on recidivism among juvenile offenders.

    PubMed

    Grunwald, Heidi E; Lockwood, Brian; Harris, Philip W; Mennis, Jeremy

    2010-09-01

    This study examined the effects of neighborhood context on juvenile recidivism to determine if neighborhoods influence the likelihood of reoffending. Although a large body of literature exists regarding the impact of environmental factors on delinquency, very little is known about the effects of these factors on juvenile recidivism. The sample analyzed includes 7,061 delinquent male juveniles committed to community-based programs in Philadelphia, of which 74% are Black, 13% Hispanic, and 11% White. Since sample youths were nested in neighborhoods, a hierarchical generalized linear model was employed to predict recidivism across three general categories of recidivism offenses: drug, violent, and property. Results indicate that predictors vary across the types of offenses and that drug offending differs from property and violent offending. Neighborhood-level factors were found to influence drug offense recidivism, but were not significant predictors of violent offenses, property offenses, or an aggregated recidivism measure, despite contrary expectations. Implications stemming from the finding that neighborhood context influences only juvenile drug recidivism are discussed.

  6. Insulin receptor-mediated nutritional signalling regulates juvenile hormone biosynthesis and vitellogenin production in the German cockroach.

    PubMed

    Abrisqueta, Marc; Süren-Castillo, Songül; Maestro, José L

    2014-06-01

    Female reproductive processes, which comprise, amongst others, the synthesis of yolk proteins and the endocrine mechanisms which regulate this synthesis, need a considerable amount of energy and resources. The role of communicating that the required nutritional status has been attained is carried out by nutritional signalling pathways and, in particular, by the insulin receptor (InR) pathway. In the present study, using the German cockroach, Blattella germanica, as a model, we analysed the role of InR in different processes, but mainly those related to juvenile hormone (JH) synthesis and vitellogenin production. We first cloned the InR cDNA from B. germanica (BgInR) and then determined that its expression levels were constant in corpora allata and fat body during the first female gonadotrophic cycle. Results showed that the observed increase in BgInR mRNA in fat body from starved compared to fed females was abolished in those females treated with systemic RNAi in vivo against the transcription factor BgFoxO. RNAi-mediated BgInR knockdown during the final two nymphal stages produced significant delays in the moults, together with smaller adult females which could not spread the fore- and hindwings properly. In addition, BgInR knockdown led to a severe inhibition of juvenile hormone synthesis in adult female corpora allata, with a concomitant reduction of mRNA levels corresponding to 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) synthase-1, HMG-CoA synthase-2, HMG-CoA reductase and methyl farnesoate epoxidase. BgInR RNAi treatment also reduced fat body vitellogenin mRNA and oocyte growth. Our results show that BgInR knockdown produces similar phenotypes to those obtained in starved females in terms of corpora allata activity and vitellogenin synthesis, and indicate that the InR pathway mediates the activation of JH biosynthesis and vitellogenin production elicited by nutrition signalling.

  7. A whole genome screening and RNA interference identify a juvenile hormone esterase-like gene of the diamondback moth, Plutella xylostella.

    PubMed

    Gu, Xiaojun; Kumar, Sunil; Kim, Eunjin; Kim, Yonggyun

    2015-09-01

    Juvenile hormone (JH) plays a crucial role in preventing precocious metamorphosis and stimulating reproduction. Thus, its hemolymph titer should be under a tight control. As a negative controller, juvenile hormone esterase (JHE) performs a rapid breakdown of residual JH in the hemolymph during last instar to induce a larval-to-pupal metamorphosis. A whole genome of the diamondback moth (DBM), Plutella xylostella, has been annotated and proposed 11 JHE candidates. Sequence analysis using conserved motifs commonly found in other JHEs proposed a putative JHE (Px004817). Px004817 (64.61 kDa, pI=5.28) exhibited a characteristic JHE expression pattern by showing high peak at the early last instar, at which JHE enzyme activity was also at a maximal level. RNA interference of Px004817 reduced JHE activity and interrupted pupal development with a significant increase of larval period. This study identifies Px004817 as a JHE-like gene of P. xylostella.

  8. Insect juvenile hormone mimics against the short-nosed cattle louse, Haematopinus eurysternus Denny (Anoplura), and their effect on warbles of Hypoderma sp. Latr. (Diptera:Oestridae).

    PubMed

    Meleney, W P; Roberts, I H

    1975-10-01

    Insect juvenile hormone mimics (IJH) at 0.1 and 0.01% were used as sprays for control of the short-nosed cattle louse, Haematopinus eurysternus Denny, on 11 heavily infested Hereford cows. A significant reduction of lice occurred although eradication was achieved in only one case. Severe reactions, apparently associated with the death or failure of complete development of cattle grub larvae, Hypoderma sp. Latr., were seen in the IJH-treated cows.

  9. Function of Phe-259 and Thr-314 within the Substrate Binding Pocket of the Juvenile Hormone Esterase of Manduca sexta†

    PubMed Central

    Kamita, Shizuo G.; Wogulis, Mark D.; Law, Christopher S.; Morisseau, Christophe; Tanaka, Hiromasa; Huang, Huazhang; Wilson, David K.; Hammock, Bruce D.

    2013-01-01

    Juvenile hormone (JH) is a key insect developmental hormone that is found at low nanomolar levels in larval insects. The methyl ester of JH is hydrolyzed in many insects by an esterase that shows high specificity for JH. We have previously determined a crystal structure of the JH esterase (JHE) of the tobacco hornworm Manduca sexta (MsJHE) [Wogulis, M., Wheelock, C. E., Kamita, S. G., Hinton, A. C., Whetstone, P. A., Hammock, B. D., and Wilson, D. K. (2006) Biochemistry 45, 4045-4057]. Our molecular modeling indicates that JH fits very tightly within the substrate binding pocket of MsJHE. This tight fit places two non-catalytic amino acid residues, Phe-259 and Thr-314, within the appropriate distance and geometry to potentially interact with the α,β-unsaturated ester and epoxide, respectively, of JH. These residues are highly conserved in numerous biologically active JHEs. Kinetic analyses of mutants of Phe-259 or Thr-314 indicate that these residues contribute to the low KM that MsJHE shows for JH. This low KM, however, comes at the cost of reduced substrate turnover. Neither nucleophilic attack of the resonance stabilized ester by the catalytic serine nor the availability of a water molecule for attack of the acyl-enzyme intermediate appear to be a rate-determining step in the hydrolysis of JH by MsJHE. We hypothesize that the release of the JH acid metabolite from the substrate binding pocket limits the catalytic cycle. Our findings also demonstrate that chemical bond strength does not necessarily correlate with how reactive the bond will be to metabolism. PMID:20307057

  10. Control of larval-pupal-adult molt in the moth Sesamia nonagrioides by juvenile hormone and ecdysteroids.

    PubMed

    Pérez-Hedo, Meritxell; Goodman, Walter G; Schafellner, Christa; Martini, Antonio; Sehnal, Frantisek; Eizaguirre, Matilde

    2011-05-01

    Sesamia nonagrioides (Lepidoptera: Noctuidae) larvae reared under long day (LD; 16L:8D) conditions pupate after 5 or 6 larval instars, whereas under short day (SD; 12L:12D) conditions they undergo up to 12 additional molts before pupating. This extended period of repeated molting is maintained by high levels of juvenile hormone (JH). Previous work demonstrated that both LD and SD larvae decapitated in the 6th instar pupate but further development is halted. By contrast, about one-third of SD larvae from which only the brain has been removed, undergo first a larval molt, then pupate and subsequently developed to the adult stage. Debrained LD larvae molt to larvae exceptionally but regularly pupate and produce adults. Implanted brains may induce several larval molts in debrained recipient larvae irrespectively of the photoperiodic conditions. The results of present work demonstrate that the prothoracic glands (PGs) and the corpora allata (CA) of debrained larvae continue to produce ecdysteroids and JHs, respectively. PGs are active also in the decapitated larvae that lack JH, consistent with the paradigm that CA, which are absent in the decapitated larvae, are the only source of this hormone. Completion of the pupal-adult transformation in both LD and SD debrained insects demonstrates that brain is not crucial for the development of S. nonagrioides but is required for diapause maintenance. Application of JH to headless pupae induces molting, presumably by activating their PGs. It is likely that JH plays this role also in the induction of pupal-adult transformation in debrained insects. Application of the ecdysteroid agonist RH 2485 (methoxyfenozide) to headless pupae also elicits molting: newly secreted cuticle is in some cases thin and indifferent, in other cases it bears distinct pupal or adult features.

  11. Juvenile hormone titers, ovarian status and epicuticular hydrocarbons in gynes and workers of the paper wasp Belonogaster longitarsus.

    PubMed

    Kelstrup, Hans C; Hartfelder, Klaus; Esterhuizen, Nanike; Wossler, Theresa C

    2017-04-01

    The prevailing paradigm for social wasp endocrinology is that of juvenile hormone (JH) functioning pleiotropically in potential and actual queens, where it fuels dominance behaviors, stimulates ovarian growth and/or affects the production of status-linked cuticular compounds. In colonies with annual cycles (e.g., temperate-zone species), female adults produced at the end of the summer (called gynes) are physiologically primed to hibernate. Despite the absence of egg-laying in the pre-overwintering phase, gynes engage in dominance interactions that may affect reproductive potential following hibernation. JH levels have long been inferred to be low in gynes but this has never been tested. In what is the first study to measure JH in gyne-containing colonies of a temperate paper wasp, and the first to incorporate hormone assays in Belonogaster, our results show that the JH titer positively correlates with gyne-specific traits (including oocyte length and a low frequency of foraging trips) in B. longitarsus, a South African paper wasp. Measures of dominance correlated with oocyte length, but not all dominant females possessed activated ovaries. The cuticular hydrocarbon profiles of gynes and workers were distinct, with oocyte length and JH titer showing a positive association with longer-chain methyl-branched alkanes. Nonetheless, evidence for a role of JH in dominance was inconclusive. Finally, the range of JH titers among gynes, and the positive association of JH titers with ovarian status and prospective fertility signals, makes it unlikely that the gyne phenotype is maintained by low JH levels.

  12. A cumulative feeding threshold required for vitellogenesis can be obviated with juvenile hormone treatment in lubber grasshoppers

    PubMed Central

    Fronstin, R. B.; Hatle, J. D.

    2008-01-01

    SUMMARY Developmental thresholds can ensure that an adequate condition has been attained to proceed through major transitions (e.g. initiation of reproduction, metamorphosis). Nutrition is critical to attaining most thresholds, because it is needed for both growth and storage. Attaining a threshold typically stimulates the release of hormones that commit the animal to the developmental transition, yet the relationships between the nutrition needed for developmental thresholds and these endocrine signals are poorly understood. Lubber grasshoppers require a cumulative feeding threshold to initiate vitellogenesis and potentially commit to oviposition. We tested the relative roles of the nutritional threshold and the major gonadotropin (juvenile hormone; JH) in initiating vitellogenesis and committing to oviposition. The source of JH was removed from all females, and then JH analog was applied after different amounts of feeding. Threshold feeding was not required to initiate vitellogenesis, suggesting that sub-threshold grasshoppers are competent to respond to JH. Further, sub-threshold grasshoppers went on to oviposit earlier than supra-threshold grasshoppers treated with JH at the same time. Hence, threshold feeding is required only to cause the production and release of JH. At the same time, we also found that individuals that were restored with JH late in life tended to favor current reproduction, at the expense of future reproduction. Both time to oviposition and vitellogenin profiles were consistent with this developmental allocation. Taken together, our results suggest that lubber grasshoppers adjust reproductive tactics primarily in response to nutrition (which only serves to release JH) and secondarily in response to age. PMID:18083735

  13. Juvenile hormone analog technology: effects on larval cannibalism and the production of Spodoptera exigua (Lepidoptera: Noctuidae) nucleopolyhedrovirus.

    PubMed

    Elvira, Sonia; Williams, Trevor; Caballero, Primitivo

    2010-06-01

    The production of a multiple nucleopolyhedrovirus (SeMNPV) of the beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae), has been markedly increased by using juvenile hormone analog (JHA) technology to generate a supernumerary sixth instar in the species. In the current study we compared the incidence of cannibalism in S. exigua fifth and sixth instars reared at low (two larvae per dish) and a high density (10 larvae per dish). The incidence of cannibalism was significantly higher in fifth instars compared with sixth instars and increased with rearing density on both instars. Infected larvae were more prone to become victims of cannibalism than healthy individuals in mixed groups comprising 50% healthy + 50% infected larvae in both instars reared at high density. Instar had a marked effect on occlusion body (OB) production because JHA-treated insects produced between 4.8- and 5.6-fold increase in OB production per dish compared with fifth instars at high and low densities, respectively. The insecticidal characteristics of OBs produced in JHA-treated insects, as indicated by LD50 values, were similar to those produced in untreated fourth or fifth instars. Because JHA technology did not increase the prevalence of cannibalism and had no adverse effect on the insecticidal properties of SeMNPV OBs, we conclude that the use of JHAs to generate a supernumerary instar is likely to be compatible with mass production systems that involve gregarious rearing of infected insects.

  14. Larval Exposure to the Juvenile Hormone Analog Pyriproxyfen Disrupts Acceptance of and Social Behavior Performance in Adult Honeybees

    PubMed Central

    Fourrier, Julie; Deschamps, Matthieu; Droin, Léa; Alaux, Cédric; Fortini, Dominique; Beslay, Dominique; Le Conte, Yves; Devillers, James; Aupinel, Pierrick; Decourtye, Axel

    2015-01-01

    Background Juvenile hormone (JH) plays an important role in honeybee development and the regulation of age-related division of labor. However, honeybees can be exposed to insect growth regulators (IGRs), such as JH analogs developed for insect pest and vector control. Although their side effects as endocrine disruptors on honeybee larval or adult stages have been studied, little is known about the subsequent effects on adults of a sublethal larval exposure. We therefore studied the impact of the JH analog pyriproxyfen on larvae and resulting adults within a colony under semi-field conditions by combining recent laboratory larval tests with chemical analysis and behavioral observations. Oral and chronic larval exposure at cumulative doses of 23 or 57 ng per larva were tested. Results Pyriproxyfen-treated bees emerged earlier than control bees and the highest dose led to a significant rate of malformed adults (atrophied wings). Young pyriproxyfen-treated bees were more frequently rejected by nestmates from the colony, inducing a shorter life span. This could be linked to differences in cuticular hydrocarbon (CHC) profiles between control and pyriproxyfen-treated bees. Finally, pyriproxyfen-treated bees exhibited fewer social behaviors (ventilation, brood care, contacts with nestmates or food stocks) than control bees. Conclusion Larval exposure to sublethal doses of pyriproxyfen affected several life history traits of the honeybees. Our results especially showed changes in social integration (acceptance by nestmates and social behaviors performance) that could potentially affect population growth and balance of the colony. PMID:26171610

  15. Juvenile hormone-dopamine systems for the promotion of flight activity in males of the large carpenter bee Xylocopa appendiculata

    NASA Astrophysics Data System (ADS)

    Sasaki, Ken; Nagao, Takashi

    2013-12-01

    The reproductive roles of dopamine and dopamine regulation systems are known in social hymenopterans, but the knowledge on the regulation systems in solitary species is still needed. To test the possibility that juvenile hormone (JH) and brain dopamine interact to trigger territorial flight behavior in males of a solitary bee species, the effects on biogenic amines of JH analog treatments and behavioral assays with dopamine injections in males of the large carpenter bee Xylocopa appendiculata were quantified. Brain dopamine levels were significantly higher in methoprene-treated males than in control males 4 days after treatment, but were not significantly different after 7 days. Brain octopamine and serotonin levels did not differ between methoprene-treated and control males at 4 and 7 days after treatment. Injection of dopamine caused significantly higher locomotor activities and a shorter duration for flight initiation in experimental versus control males. These results suggest that brain dopamine can be regulated by JH and enhances flight activities in males. The JH-dopamine system in males of this solitary bee species is similar to that of males of the highly eusocial honeybee Apis mellifera.

  16. Juvenile hormone analog enhances calling behavior, mating success, and quantity of volatiles released by Anastrepha obliqua (Diptera: Tephritidae).

    PubMed

    Chacón-Benavente, Roxana; López-Guillen, Guillermo; Hernández, Emilio; Rojas, Julio C; Malo, Edi A

    2013-04-01

    The application of a juvenile hormone analog, methoprene, to newly emerged adult males reduced the time required for sexual maturation and enhanced mating success in several species of tephritid fruit flies. In this work, we investigated the effect of topical methoprene application on West Indian fruit fly, Anastrepha obliqua (Macquart), male calling, mating, and volatile release. Males treated with topical methoprene exhibited sexual maturation and reproductive behavior 2 d earlier when compared with control males treated with acetone. Methoprene-treated males began calling and mating at 4 d old, whereas control males did not call and mate until 6 d old. The gas chromotography-mass spectrometry analysis of volatiles showed that during calling A. obliqua males consistently released four compounds; three of them were identified as (Z)-3-nonenol, (Z,E)-α-farnesene, (E,E)-α-farnesene, and a fourth compound with the appearance of a farnesene isomer. Both treated and control males released the same compounds, although treated males started to release volatiles before that control males. The results are discussed in view of possible methoprene application with the aim of reducing costs in fly emergence and release facilities before eventual release of A. obliqua in the field, thus improving the sterile insect technique.

  17. Juvenile Hormone (JH) Esterase of the Mosquito Culex quinquefasciatus Is Not a Target of the JH Analog Insecticide Methoprene

    PubMed Central

    Kamita, Shizuo G.; Samra, Aman I.; Liu, Jun-Yan; Cornel, Anthony J.; Hammock, Bruce D.

    2011-01-01

    Juvenile hormones (JHs) are essential sesquiterpenes that control insect development and reproduction. JH analog (JHA) insecticides such as methoprene are compounds that mimic the structure and/or biological activity of JH. In this study we obtained a full-length cDNA, cqjhe, from the southern house mosquito Culex quinquefasciatus that encodes CqJHE, an esterase that selectively metabolizes JH. Unlike other recombinant esterases that have been identified from dipteran insects, CqJHE hydrolyzed JH with specificity constant (kcat/KM ratio) and Vmax values that are common among JH esterases (JHEs). CqJHE showed picomolar sensitivity to OTFP, a JHE-selective inhibitor, but more than 1000-fold lower sensitivity to DFP, a general esterase inhibitor. To our surprise, CqJHE did not metabolize the isopropyl ester of methoprene even when 25 pmol of methoprene was incubated with an amount of CqJHE that was sufficient to hydrolyze 7,200 pmol of JH to JH acid under the same assay conditions. In competition assays in which both JH and methoprene were available to CqJHE, methoprene did not show any inhibitory effects on the JH hydrolysis rate even when methoprene was present in the assay at a 10-fold higher concentration relative to JH. Our findings indicated that JHE is not a molecular target of methoprene. Our findings also do not support the hypothesis that methoprene functions in part by inhibiting the action of JHE. PMID:22174797

  18. Juvenile hormone biosynthesis gene expression in the corpora allata of honey bee (Apis mellifera L.) female castes.

    PubMed

    Bomtorin, Ana Durvalina; Mackert, Aline; Rosa, Gustavo Conrado Couto; Moda, Livia Maria; Martins, Juliana Ramos; Bitondi, Márcia Maria Gentile; Hartfelder, Klaus; Simões, Zilá Luz Paulino

    2014-01-01

    Juvenile hormone (JH) controls key events in the honey bee life cycle, viz. caste development and age polyethism. We quantified transcript abundance of 24 genes involved in the JH biosynthetic pathway in the corpora allata-corpora cardiaca (CA-CC) complex. The expression of six of these genes showing relatively high transcript abundance was contrasted with CA size, hemolymph JH titer, as well as JH degradation rates and JH esterase (jhe) transcript levels. Gene expression did not match the contrasting JH titers in queen and worker fourth instar larvae, but jhe transcript abundance and JH degradation rates were significantly lower in queen larvae. Consequently, transcriptional control of JHE is of importance in regulating larval JH titers and caste development. In contrast, the same analyses applied to adult worker bees allowed us inferring that the high JH levels in foragers are due to increased JH synthesis. Upon RNAi-mediated silencing of the methyl farnesoate epoxidase gene (mfe) encoding the enzyme that catalyzes methyl farnesoate-to-JH conversion, the JH titer was decreased, thus corroborating that JH titer regulation in adult honey bees depends on this final JH biosynthesis step. The molecular pathway differences underlying JH titer regulation in larval caste development versus adult age polyethism lead us to propose that mfe and jhe genes be assayed when addressing questions on the role(s) of JH in social evolution.

  19. Mode of action of allatostatins in the regulation of juvenile hormone biosynthesis in the cockroach, Diploptera punctata.

    PubMed

    Huang, Juan; Marchal, Elisabeth; Hult, Ekaterina F; Zels, Sven; Vanden Broeck, Jozef; Tobe, Stephen S

    2014-11-01

    The FGLamide allatostatins (FGL/ASTs) are a family of neuropeptides with pleiotropic functions, including the inhibition of juvenile hormone (JH) biosynthesis, vitellogenesis and muscle contraction. In the cockroach, Diploptera punctata, thirteen FGLa/ASTs and one allatostatin receptor (AstR) have been identified. However, the mode of action of ASTs in regulation of JH biosynthesis remains unclear. Here, we determined the tissue distribution of Dippu-AstR. And we expressed Dippu-AstR in vertebrate cell lines, and activated the receptor with the Dippu-ASTs. Our results show that all thirteen ASTs activated Dippu-AstR in a dose dependent manner, albeit with different potencies. Functional analysis of AstR in multiple cell lines demonstrated that activation of the AstR receptor resulted in elevated levels of Ca(2+) and cAMP, which suggests that Dippu-AstR can act through the Gαq and Gαs protein pathways. The study on the target of AST action reveals that FGL/AST affects JH biosynthesis prior to the entry of acetyl-CoA into the JH biosynthetic pathway. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Insecticidal, anti-juvenile hormone, and fungicidal activities of organic extracts from different Penicillium species and their isolated active components.

    PubMed

    Castillo, M A; Moya, P; Cantín, A; Miranda, M A; Primo, J; Hernández, E; Primo-Yúfera, E

    1999-05-01

    Organic extracts from mycelium and culture broth of 21 Penicillium isolates have been tested for insecticidal, insect anti-juvenile hormone (anti-JH), and antifungal activities. Culture broth extracts were the most active, mainly against insects; nearly 25% of them have shown high entomotoxicity (100% mortality at 100 microg/cm(2)). A strong in vivo anti-JH activity against Oncopeltus fasciatus Dallas was detected in the culture broth extracts from P. brevicompactum P79 and P88 isolates. The two new natural products isolated from P79, N-(2-methyl-3-oxodec-8-enoyl)-2-pyrroline (1) and 2-hept-5-enyl-3-methyl-4-oxo-6,7,8,8a-tetrahydro-4H-pyrrolo[2,1-b]-1, 3-oxazine (2), possessed anti-JH and insecticidal activity, respectively, against O. fasciatus. Synthesized natural compound 1 has shown an ED(50) of 0.7 microg/nymph when assayed on newly molted fourth-instar nymphs of O. fasciatus. Promising biological activities have also been detected in the synthetic precursors.

  1. Heat Shock Protein 83 (Hsp83) Facilitates Methoprene-tolerant (Met) Nuclear Import to Modulate Juvenile Hormone Signaling*

    PubMed Central

    He, Qianyu; Wen, Di; Jia, Qiangqiang; Cui, Chunlai; Wang, Jian; Palli, Subba R.; Li, Sheng

    2014-01-01

    Juvenile hormone (JH) receptors, methoprene-tolerant (Met) and Germ-cell expressed (Gce), transduce JH signals to induce Kr-h1 expression in Drosophila. Dual luciferase assay identified a 120-bp JH response region (JHRR) in the Kr-h1α promoter. Both in vitro and in vivo experiments revealed that Met and Gce transduce JH signals to induce Kr-h1 expression through the JHRR. DNA affinity purification identified chaperone protein Hsp83 as one of the proteins bound to the JHRR in the presence of JH. Interestingly, Hsp83 physically interacts with PAS-B and basic helix-loop-helix domains of Met, and JH induces Met-Hsp83 interaction. As determined by immunohistochemistry, Met is mainly distributed in the cytoplasm of fat body cells of the larval when the JH titer is low and JH induces Met nuclear import. Hsp83 was accumulated in the cytoplasm area adjunct to the nucleus in the presence of JH and Met/Gce. Loss-of-function of Hsp83 attenuated JH binding and JH-induced nuclear import of Met, resulting in a decrease in the JHRR-driven reporter activity leading to reduction of Kr-h1 expression. These data show that Hsp83 facilitates the JH-induced nuclear import of Met that induces Kr-h1 expression through the JHRR. PMID:25122763

  2. Juvenile Hormone Biosynthesis Gene Expression in the corpora allata of Honey Bee (Apis mellifera L.) Female Castes

    PubMed Central

    Rosa, Gustavo Conrado Couto; Moda, Livia Maria; Martins, Juliana Ramos; Bitondi, Márcia Maria Gentile; Hartfelder, Klaus; Simões, Zilá Luz Paulino

    2014-01-01

    Juvenile hormone (JH) controls key events in the honey bee life cycle, viz. caste development and age polyethism. We quantified transcript abundance of 24 genes involved in the JH biosynthetic pathway in the corpora allata-corpora cardiaca (CA-CC) complex. The expression of six of these genes showing relatively high transcript abundance was contrasted with CA size, hemolymph JH titer, as well as JH degradation rates and JH esterase (jhe) transcript levels. Gene expression did not match the contrasting JH titers in queen and worker fourth instar larvae, but jhe transcript abundance and JH degradation rates were significantly lower in queen larvae. Consequently, transcriptional control of JHE is of importance in regulating larval JH titers and caste development. In contrast, the same analyses applied to adult worker bees allowed us inferring that the high JH levels in foragers are due to increased JH synthesis. Upon RNAi-mediated silencing of the methyl farnesoate epoxidase gene (mfe) encoding the enzyme that catalyzes methyl farnesoate-to-JH conversion, the JH titer was decreased, thus corroborating that JH titer regulation in adult honey bees depends on this final JH biosynthesis step. The molecular pathway differences underlying JH titer regulation in larval caste development versus adult age polyethism lead us to propose that mfe and jhe genes be assayed when addressing questions on the role(s) of JH in social evolution. PMID:24489805

  3. Juvenile hormone-dopamine systems for the promotion of flight activity in males of the large carpenter bee Xylocopa appendiculata.

    PubMed

    Sasaki, Ken; Nagao, Takashi

    2013-12-01

    The reproductive roles of dopamine and dopamine regulation systems are known in social hymenopterans, but the knowledge on the regulation systems in solitary species is still needed. To test the possibility that juvenile hormone (JH) and brain dopamine interact to trigger territorial flight behavior in males of a solitary bee species, the effects on biogenic amines of JH analog treatments and behavioral assays with dopamine injections in males of the large carpenter bee Xylocopa appendiculata were quantified. Brain dopamine levels were significantly higher in methoprene-treated males than in control males 4 days after treatment, but were not significantly different after 7 days. Brain octopamine and serotonin levels did not differ between methoprene-treated and control males at 4 and 7 days after treatment. Injection of dopamine caused significantly higher locomotor activities and a shorter duration for flight initiation in experimental versus control males. These results suggest that brain dopamine can be regulated by JH and enhances flight activities in males. The JH-dopamine system in males of this solitary bee species is similar to that of males of the highly eusocial honeybee Apis mellifera.

  4. Larval Exposure to the Juvenile Hormone Analog Pyriproxyfen Disrupts Acceptance of and Social Behavior Performance in Adult Honeybees.

    PubMed

    Fourrier, Julie; Deschamps, Matthieu; Droin, Léa; Alaux, Cédric; Fortini, Dominique; Beslay, Dominique; Le Conte, Yves; Devillers, James; Aupinel, Pierrick; Decourtye, Axel

    2015-01-01

    Juvenile hormone (JH) plays an important role in honeybee development and the regulation of age-related division of labor. However, honeybees can be exposed to insect growth regulators (IGRs), such as JH analogs developed for insect pest and vector control. Although their side effects as endocrine disruptors on honeybee larval or adult stages have been studied, little is known about the subsequent effects on adults of a sublethal larval exposure. We therefore studied the impact of the JH analog pyriproxyfen on larvae and resulting adults within a colony under semi-field conditions by combining recent laboratory larval tests with chemical analysis and behavioral observations. Oral and chronic larval exposure at cumulative doses of 23 or 57 ng per larva were tested. Pyriproxyfen-treated bees emerged earlier than control bees and the highest dose led to a significant rate of malformed adults (atrophied wings). Young pyriproxyfen-treated bees were more frequently rejected by nestmates from the colony, inducing a shorter life span. This could be linked to differences in cuticular hydrocarbon (CHC) profiles between control and pyriproxyfen-treated bees. Finally, pyriproxyfen-treated bees exhibited fewer social behaviors (ventilation, brood care, contacts with nestmates or food stocks) than control bees. Larval exposure to sublethal doses of pyriproxyfen affected several life history traits of the honeybees. Our results especially showed changes in social integration (acceptance by nestmates and social behaviors performance) that could potentially affect population growth and balance of the colony.

  5. Juvenile hormone (JH) esterase of the mosquito Culex quinquefasciatus is not a target of the JH analog insecticide methoprene.

    PubMed

    Kamita, Shizuo G; Samra, Aman I; Liu, Jun-Yan; Cornel, Anthony J; Hammock, Bruce D

    2011-01-01

    Juvenile hormones (JHs) are essential sesquiterpenes that control insect development and reproduction. JH analog (JHA) insecticides such as methoprene are compounds that mimic the structure and/or biological activity of JH. In this study we obtained a full-length cDNA, cqjhe, from the southern house mosquito Culex quinquefasciatus that encodes CqJHE, an esterase that selectively metabolizes JH. Unlike other recombinant esterases that have been identified from dipteran insects, CqJHE hydrolyzed JH with specificity constant (k(cat)/K(M) ratio) and V(max) values that are common among JH esterases (JHEs). CqJHE showed picomolar sensitivity to OTFP, a JHE-selective inhibitor, but more than 1000-fold lower sensitivity to DFP, a general esterase inhibitor. To our surprise, CqJHE did not metabolize the isopropyl ester of methoprene even when 25 pmol of methoprene was incubated with an amount of CqJHE that was sufficient to hydrolyze 7,200 pmol of JH to JH acid under the same assay conditions. In competition assays in which both JH and methoprene were available to CqJHE, methoprene did not show any inhibitory effects on the JH hydrolysis rate even when methoprene was present in the assay at a 10-fold higher concentration relative to JH. Our findings indicated that JHE is not a molecular target of methoprene. Our findings also do not support the hypothesis that methoprene functions in part by inhibiting the action of JHE.

  6. Effects of a juvenile hormone analogue pyriproxyfen on monogynous and polygynous colonies of the Pharaoh ant Monomorium pharaonis (Hymenoptera: Formicidae).

    PubMed

    Tay, J W; Lee, C Y

    2015-09-01

    To evaluate the effects of the juvenile hormone analogue pyriproxyfen on colonies of the Pharaoh ant Monomorium pharaonis (L.), peanut oil containing different concentrations (0.3, 0.6, or 0.9%) of pyriproxyfen was fed to monogynous (1 queen, 500 workers, and 0.1 g of brood) and polygynous (8 queens, 50 workers, and 0.1 g of brood) laboratory colonies of M. pharaonis. Due to its delayed activity, pyriproxyfen at all concentrations resulted in colony elimination. Significant reductions in brood volume were recorded at weeks 3 - 6, and complete brood mortality was observed at week 8 in all treated colonies. Brood mortality was attributed to the disruption of brood development and cessation of egg production by queens. All polygynous colonies exhibited significant reduction in the number of queens present at week 10 compared to week 1. Number of workers was significantly lower in all treated colonies compared to control colonies at week 8 due to old-age attrition of the workers without replacement. At least 98.67 ± 1.33% of workers were dead at week 10 in all treated colonies. Thus, treatment with slow acting pyriproxyfen at concentrations of 0.3 - 0.9% is an effective strategy for eliminating Pharaoh ant colonies.

  7. Sources of propionate for the biogenesis of ethyl-braced insect juvenile hormones: role of isoleucine and valine

    SciTech Connect

    Brindle, P.A.; Baker, F.C.; Tsai, L.W.; Reuter, C.C.; Schooley, D.A.

    1987-11-01

    Corpora allata from adult female Manduca sexta biosynthesis the sesquiterpenoid juvenile hormone (JH) III and the unusual ethyl-branched homologue JH II in vitro. The authors maintained corpora allata in medium 199 using (methyl-/sup 3/H)methionine as the source of the JH methyl ester moiety and as a mass marker. This allowed measurement of the relative contributions of /sup 14/C-labeled precursors to the biogenesis of JH II and III carbon skeletons. They showed efficient incorporation of a propionate equivalent, from isoleucine or valine catabolism, into the ethyl-branched portion of JH II, using double-label liquid scintillation counting of isolated JHs and gas chromatography/mass spectrometry with selected ion monitoring of JH deuteromethoxyhydrin derivatives. Methionine was a poor source of propionate for JH II biosynthesis, while glucose, succinate, threonine, and ..beta..-alanine did not contribute propionate at all. Leucine, isoleucine, and glucose incorporated into JH III and the acetate-derivative portion of JH II.

  8. The insulin/TOR signal transduction pathway is involved in the nutritional regulation of juvenile hormone synthesis in Aedes aegypti.

    PubMed

    Pérez-Hedo, Meritxell; Rivera-Perez, Crisalejandra; Noriega, Fernando G

    2013-06-01

    Juvenile hormone (JH) levels must be modulated to permit the normal progress of development and reproductive maturation in mosquitoes. JH is part of a transduction system that assesses nutritional information and controls reproduction in mosquitoes. Adult female Aedes aegypti show nutritionally-dependent dynamic changes in corpora allata (CA) JH biosynthetic activities. A coordinated expression of most JH biosynthetic enzymes has been described in female pupae and adult mosquitoes; increases or decreases in transcript levels for all the enzymes were concurrent with increases or decreases in JH synthesis; suggesting that transcriptional changes are at least partially responsible for the dynamic changes of JH biosynthesis. The goal of the present study is to identify signaling network components responsible for the nutritional-dependent changes of JH synthesis in the CA of mosquitoes. The insulin/TOR signaling network plays a central role in the transduction of nutritional signals that regulate cell growth and metabolism in insects. These pathways have also been suggested as a link between nutritional signals and JH synthesis regulation in the CA of cockroaches and flies. We used a combination of in vitro studies and in vivo genetic knockdown experiments to explore nutritional signaling pathways in the CA. Our results suggest that the insulin/TOR pathway plays a role in the transduction of the nutritional information that regulates JH synthesis in mosquitoes. Transcriptional regulation of the genes encoding JH biosynthetic enzymes is at least partially responsible for these nutritionally modulated changes of JH biosynthesis.

  9. Allatostatin-C reversibly blocks the transport of citrate out of the mitochondria and inhibits juvenile hormone synthesis in mosquitoes.

    PubMed

    Nouzova, Marcela; Rivera-Perez, Crisalejandra; Noriega, Fernando G

    2015-02-01

    Aedes aegypti allatostatin-C (AeaAST-C or PISCF-AST) is a strong and fast reversible inhibitor of juvenile hormone III (JH III) synthesis by the corpora allata (CA) of mosquitoes; however, its mechanism of action remains poorly understood. AeaAST-C showed no inhibitory activity in the presence of any of the intermediate precursors of JH III indicating that the AeaAST-C target is located before the entry of acetyl-CoA in the pathway. Stimulation experiments using different sources of carbon (glucose, pyruvate, acetate and citrate) suggest that AST-C acts after pyruvate is transformed to citrate in the mitochondria. In vitro inhibition of the citrate mitochondrial carrier (CIC) mimicked the effect of AeaAST-C, and was overridden by addition of citrate or acetate. Our results provide compelling evidence that AeaAST-C inhibits JH III synthesis by blocking the CIC carrier that transports citrate from the mitochondria to the cytosol, obstructing the production of cytoplasmic acetyl-CoA that sustains JH III synthesis in the CA of mosquitoes.

  10. Control of larval and egg development in Aedes aegypti with RNA interference against juvenile hormone acid methyl transferase.

    PubMed

    Van Ekert, Evelien; Powell, Charles A; Shatters, Robert G; Borovsky, Dov

    2014-11-01

    RNA interference (RNAi) is a powerful approach for elucidating gene functions in a variety of organisms, including mosquitoes and many other insects. Little has been done, however, to harness this approach in order to control adult and larval mosquitoes. Juvenile hormone (JH) plays a pivotal role in the control of reproduction in adults and metamorphism in larval mosquitoes. This report describes an approach to control Aedes aegypti using RNAi against JH acid methyl transferase (AeaJHAMT), the ultimate enzyme in the biosynthetic pathway of JH III that converts JH acid III (JHA III) into JH III. In female A. aegypti that were injected or fed jmtA dsRNA targeting the AeaJHAMT gene (jmtA) transcript, egg development was inhibited in 50% of the treated females. In mosquito larvae that were fed transgenic Pichia pastoris cells expressing long hair pin (LHP) RNA, adult eclosion was delayed by 3 weeks causing high mortality. Northern blot analyses and qPCR studies show that jmtA dsRNA causes inhibition of jmtA transcript in adults and larvae, which is consistent with the observed inhibition of egg maturation and larval development. Taken together, these results suggest that jmtA LHP RNA expressed in heat inactivated genetically modified P. pastoris cells could be used to control mosquito populations in the marsh.

  11. Synchronous vitellogenin expression and sexual maturation during migration are negatively correlated with juvenile hormone levels in Mythimna separata

    PubMed Central

    Xiao, Hai-Jun; Fu, Xiao-Wei; Liu, Yong-Qiang; Wu, Kong-Ming

    2016-01-01

    Annual migration of pests between different seasonal habitats can lead to serious crop damage. Reproductive immaturity is generally associated with the migratory process (oogenesis-flight syndrome), but the mechanism of reproductive development during migration varies unpredictably. Here, the vitellogenin gene (MsVg) and three key regulatory enzyme genes (MsJhamt, MsJheh and MsJhe) related to juvenile hormone (JH) synthesis and degradation were identified and characterized in Mythimna separata. The relative expression of MsVg varied significantly in response to seasonal changes and was significantly correlated with stages of ovarian development. The relatively low levels of JH titer did not differ significantly in male moths but slightly increased in female adults during the migratory season, which was consistent with changes in mRNA levels for MsJhamt, MsJheh and MsJhe. JH titer was negatively associated with relative seasonal levels of vitellogenin mRNA transcripts and with ovarian development in migrating M. separata. The synchrony of MsVg expression with sexual maturation highlighted the potential of MsVg transcript levels to serve as an index to monitor the adult reproductive status. In addition, the level of JH and sexual maturity were correlated with the extent of JH in regulating the MsVg expression and reproduction during seasonal northern and southern migration. PMID:27629246

  12. Characterization of a juvenile hormone-regulated chymotrypsin-like serine protease gene in Aedes aegypti mosquito.

    PubMed

    Bian, Guowu; Raikhel, Alexander S; Zhu, Jinsong

    2008-02-01

    After female mosquitoes ingest blood from vertebrate hosts, exopeptidases and endopeptidases are required for digesting blood proteins in the midgut into amino acids, which female mosquitoes use to build yolk proteins. These proteases are not always present in the midgut, and their diverse expression patterns suggest that production of these enzymes is highly regulated in order to meet specific physiological demands at various stages. Here we report identification of a serine-type protease, JHA15, in the yellow fever mosquito Aedes aegypti. This protein shares high sequence homology with chymotrypsins, and indeed exhibits specific chymotrypsin enzymatic activity. The JHA15 gene is expressed primarily in the midgut of adult female mosquitoes. Our results indicate that its transcription is activated by juvenile hormone in the newly emerged female adults. Although its mRNA profile is similar to that of the early trypsin gene, we found that JHA15 proteins were readily detected in the midgut epithelium cells of both non-blood-fed and blood-fed mosquitoes. Analysis of polysomal RNA further substantiated that synthesis of JHA15 occurs before and shortly after blood feeding. Knocking down expression of JHA15 resulted in no evident phenotypic changes, implying that functional redundancy exists among those proteolytic enzymes.

  13. Identification and characterization of a juvenile hormone (JH) response region in the JH esterase gene from the spruce budworm, Choristoneura fumiferana.

    PubMed

    Kethidi, Damodar R; Perera, Srini C; Zheng, S; Feng, Qi-Li; Krell, Peter; Retnakaran, Arthur; Palli, Subba R

    2004-05-07

    Using a differential display of mRNA technique we discovered that the juvenile hormone (JH) esterase gene (Cfjhe) from Choristoneura fumiferana is directly induced by juvenile hormone I (JH I), and the JH I induction is suppressed by 20-hydroxyecdysone (20E). To study the mechanism of action of these two hormones in the regulation of expression of this gene, we cloned the 1270-bp promoter region of the Cfjhe gene and identified a 30-bp region that is located between -604 and -574 and is sufficient to support both JH I induction and 20E suppression. This 30-bp region contains two conserved hormone response element half-sites separated by a 4-nucleotide spacer similar to the direct repeat 4 element and is designated as a putative juvenile hormone response element (JHRE). In CF-203 cells, a luciferase reporter placed under the control of JHRE and a minimal promoter was induced by JH I in a dose- and time-dependent manner. Moreover, 20E suppressed this JH I-induced luciferase activity in a dose- and time-dependent manner. Nuclear proteins isolated from JH I-treated CF-203 cells bound to JHRE and the binding was competed by a 100-fold excess of the cold probe but not by 100-fold excess of double-stranded oligonucleotides of unrelated sequence. JH I induced/modified nuclear proteins prior to their binding to JHRE and 20E suppressed this JH I induction/modification. These results suggest that the 30-bp JHRE identified in the Cfjhe gene promoter is sufficient to support JH induction and 20E suppression of the Cfjhe gene.

  14. Brain sex differences and hormone influences: a moving experience?

    PubMed

    Tobet, S; Knoll, J G; Hartshorn, C; Aurand, E; Stratton, M; Kumar, P; Searcy, B; McClellan, K

    2009-03-01

    Sex differences in the nervous system come in many forms. Although a majority of sexually dimorphic characteristics in the brain have been described in older animals, mechanisms that determine sexually differentiated brain characteristics often operate during critical perinatal periods. Both genetic and hormonal factors likely contribute to physiological mechanisms in development to generate the ontogeny of sexual dimorphisms in brain. Relevant mechanisms may include neurogenesis, cell migration, cell differentiation, cell death, axon guidance and synaptogenesis. On a molecular level, there are several ways to categorize factors that drive brain development. These range from the actions of transcription factors in cell nuclei that regulate the expression of genes that control cell development and differentiation, to effector molecules that directly contribute to signalling from one cell to another. In addition, several peptides or proteins in these and other categories might be referred to as 'biomarkers' of sexual differentiation with undetermined functions in development or adulthood. Although a majority of sex differences are revealed as a direct consequence of hormone actions, some may only be revealed after genetic or environmental disruption. Sex differences in cell positions in the developing hypothalamus, and steroid hormone influences on cell movements in vitro, suggest that cell migration may be one target for early molecular actions that impact brain development and sexual differentiation.

  15. Intergenerational effect of juvenile hormone on offspring in Pogonomyrmex harvester ants

    USDA-ARS?s Scientific Manuscript database

    Parents can influence the phenotypes of their offspring via a number of mechanisms. In harvester ants, whether female progeny develop into workers or daughter queens is strongly influenced by the age and temperature conditions experienced by their mother, which is associated with variation in mater...

  16. Hormonal and developmental influences on adolescent suicide: a systematic review.

    PubMed

    Manceaux, Pauline; Jacques, Denis; Zdanowicz, Nicolas

    2015-09-01

    Teen suicide is a major public health problem. In the United States, it is the third cause of death among the 10-24 year olds. Adolescence involves numerous changes, whether physical, social, emotional or hormonal. At a neurobiological level, a teenager's nervous system is also affected and undergoes significant modifications. We conducted a systematic review of electronic literature published between January 1990 and August 2014 via MEDLINE, PubMED and PsychINFO to list articles concerning the risk of teen depression and suicide risks in adolescents as well as those relating to the adolescent's neuro-anatomical brain and the effect that puberty has on it. When analyzing the various studies, it is clear that all support the idea that adolescence is a special period, both at neuroanatomical and biological levels. The risk of impulsiveness and depression is explained, anatomically, by a faster maturation of the limbic system, and biologically, by a higher sensitivity of the serotoninergic system and to glucocorticoids, which themselves are influenced by the specific hormonal environment during this period. Moreover and above all, adolescence is a vulnerable time for many reasons: physical, hormonal, social, cognitive, and emotional changes, self-development, etc. We should not restrict it to structural neurological changes without taking into account the other factors or compartmentalize young people into a reductive model based on determinism. Adolescence is a time of change, transformation, and adaptation. The hormonal events that occur during this period have significant effects on brain development, neuro-cerebral chemistry, adolescent behavior and risks of depression. It is important to try to prevent suicide and depression in adolescents considering its entirety and complexity but also by paying attention to neuro-biological factors even if, at present, many research projects are currently underway to develop an appropriate drug therapy strategy.

  17. On the factors influencing juvenile flatfish abundance in the lower Severn Estuary, England

    NASA Astrophysics Data System (ADS)

    Henderson, P. A.; Seaby, R. M. H.

    Bridgwater Bay within the Bristol Channel, Somerset, England is a nursery ground for sole, Solea solea, and dab, Limanda limanda, during the autumn and winter. Flounder, Platichthys flesus, both juveniles and adults, are common during the summer. Using a 13-year data set of fish in the bay, correlations were studied between climatic, predatory and competitive factors and juvenile flatfish abundance. The major factor was found to be seawater temperature. For sole, abundance was positively correlated with the temperature in the spawning period (April and May). For flounder, abundance was negatively correlated with average temperature during the previous year. For dab, average winter temperature over the spawning period was negatively correlated with juvenile abundance and with mean length observed during the following autumn. These climatic changes were also found to influence the abundance of a large number of other fish and crustacean species which were potential predators or competitors and which in some cases were significantly correlated with flatfish abundance. The data set was analysed using multiple correlation analysis. Multi-factorial models of population change which included interspecific and climatic factors were examined. Using first-order partial correlations it was possible to distinguish between different causal models. In every case it was found that inter-specific correlations were attributable to both species independently changing in abundance with temperature. No significant correlations between the abundance of potential predators or competitors and juvenile flatfish were detected.

  18. Purification and characterization of the carrier protein for juvenile hormone from the hemolymph of the tobacco hornworm Manduca sexta Johannson (Lepidoptera: Sphingidae).

    PubMed

    Kramer, K J; Dunn, P E; Peterson, R C; Seballos, H L; Sanburg, L L; Law, J H

    1976-08-25

    The larval hemolymph of the tobacco hornworm, Manduca sexta, contains a carrier protein that binds specifically and with high affinity the juvenile hormone, an important regulator of insect development. This protein serves to transport the hormone and to protect it from the action of degradative enzymes during early larval stages. Using hemolymph from the last larval stage, we have isolated a pure carrier protein using acetone precipitation, gel filtration, ion exchange chromatography, and preparative isoelectric focusing. Gel filtration, polyacrylamide gel electrophoresis in sodium dodecyl sulfate, and equilibrium ultracentrifugation established that the carrier protein is a single chain polypeptide of approximately 28,000 daltons. The amino acid composition is unexceptional, and no evidence for hexosamine has been obtained. An ion exchange filter disc assay method was used to determine the formation of the complex between the carrier protein and isotopically labeled juvenile hormone. With this technique it was shown that each carrier protein binds one hormone molecule with a dissociation constant of 4.4 +/- 0.2 X 10(-7) M at 0 degrees.

  19. Potential influence of hormones in the development of slipped capital femoral epiphysis: a preliminary study.

    PubMed

    Papavasiliou, Kyriakos A; Kirkos, John M; Kapetanos, George A; Pournaras, John

    2007-01-01

    The potential influence of hormonal imbalance on the development of slipped capital femoral epiphysis was assessed through a prospective clinical study. The serum levels of T3, T4, thyroid-stimulating hormone, testosterone, estradiol, dehydroepiandrosterone-sulfate, follicle-stimulating hormone, luteinizing hormone, human growth hormone, adrenal cortex hormone and cortisol were evaluated in seven boys and seven girls. Forty-three out of 154 hormonal determinations (27.9%) were abnormal. The results showed increased incidence of pathological values mainly in the levels of follicle-stimulating-hormone, luteinizing-hormone and testosterone. No patient had clinical findings of endocrinopathy. A (possibly) temporary hormonal disorder may play a potentially significant role in the development of slipped capital femoral epiphysis.

  20. The influence of ovarian factors on the somatostatin-growth hormone system during the postnatal growth and sexual development in lambs.

    PubMed

    Wańkowska, Marta; Polkowska, Jolanta; Misztal, Tomasz; Romanowicz, Katarzyna

    2012-07-01

    The aim of the study was to elucidate the effects of ovarian hormones on somatostatin in the hypothalamic neurons and growth hormone (GH) secretion during the postnatal growth and development of sheep. The study was performed on 9-week-old (infantile) lambs that were ovary-intact (OVI) or ovariectomized (OVX) at 39 days of age, and on 16-week-old (juvenile) lambs that were OVI or OVX at 88 days of age. Hormones in neurons and somatotropic cells were assayed with immunohistochemistry and radioimmunoassay. Following ovariectomy, immunoreactive somatostatin was more abundant (p<0.05) in the hypothalamus of infantile lambs, whereas in juvenile lambs it was more abundant (p<0.05) in the periventricular nucleus but reduced (p<0.01) in the median eminence. In contrast to somatostatin in the hypothalamus, the content of immunoreactive GH in the hypophysis was less in OVX infantile lambs, but greater in OVX juvenile lambs (p<0.05). Basal blood serum concentrations of GH were greater (p<0.05) in OVX infantile lambs, whereas in OVX juvenile lambs, mean and basal concentrations of GH and amplitude of GH pulses were less than in OVI lambs (p<0.05). The postnatal increase in body weight was greatest in middle-late infancy (p<0.01). The body weight did not differ (p>0.05) between OVI and OVX lambs. In conclusion, ovarian factors may inhibit the GH secretion in infantile lambs but enhance the GH secretion in juvenile lambs. Transition to puberty, as related to the growth rate, appears to be due mainly to change in gonadal influence on the somatostatin neurosecretion. A stimulation of somatostatin output in the median eminence by gonadal factors in infancy is followed by a stimulation of somatostatin accumulation after infancy. Thus, ovarian factors modulate mechanisms within the somatotropic system of lambs to synchronize the somatic growth with sexual development.

  1. Variability in leptin and adrenal response in juvenile Steller sea lions (Eumetopias jubatus) to adrenocorticotropic hormone (ACTH) in different seasons.

    PubMed

    Mashburn, Kendall L; Atkinson, Shannon

    2008-01-15

    Eight free-ranging juvenile Steller sea lions (SSL; 6 males, 2 females; 14-20 months) temporarily held under ambient conditions at the Alaska SeaLife Center were physiologically challenged through exogenous administration of adrenocorticotropic hormone (ACTH). Four individuals (3 males, 1 female) underwent ACTH challenge in each of two seasons, summer and winter. Following ACTH injection serial blood and fecal samples were collected for up to 3 and 96 h, respectively. A radioimmunoassay (RIA) was validated for leptin, and using a previously validated RIA for cortisol, collected sera were analyzed for both cortisol and leptin. ACTH injection resulted in a 2.9-fold increase (P=0.164) in leptin which preceded a 3.2-fold increase (P=0.0290) in cortisol by 105 min in summer. In winter, a 1.7-fold increase in leptin (P=0.020) preceded a 2.1-fold increase (P=0.001) in serum cortisol by 45 min. Mean fecal corticosteroid maxima were 10.4 and 16.7-fold above baseline 28 and 12 h post-injection and returned to baseline 52 and 32 h post-injection, in summer and winter, respectively. Data indicate acute activity in juvenile adrenal glands is detectable in feces approximately 12-24 h post-stimulus in either season, with a duration of approximately 40 h in summer and 20 h in winter. Changes in serum cortisol proved statistically significant both seasons and elevated concentrations were detected by 30 min post-stimulus (baseline 64.8+/-4.2; peak 209.5+/-18.3 ng/ml: summer; baseline 87.0+/-15.7; peak 237.6+/-10.0 ng/ml: winter), whereas the changes that occurred in serum leptin proved to be significant only in winter (baseline 6.4+/-0.6; peak 18.7+/-7.0 ng/ml: summer; baseline 4.2+/-0.5; peak 7.5+/-0.6 ng/ml: winter). Changes in fecal corticosteroids proved significant only in summer (baseline 117.8+/-36.7; peak 1219.3+/-298.4 ng/g, P=0.038: summer; baseline 71.8+/-13.7; peak 1198.6+/-369.9 ng/g, P=0.053: winter) due to a high degree of individual variability in winter months. The

  2. Presoldier induction by a juvenile hormone analog in the nasute termite Nasutitermes takasagoensis (Isoptera: Termitidae).

    PubMed

    Toga, Kouhei; Hojo, Masaru; Miura, Toru; Maekawa, Kiyoto

    2009-06-01

    The ability of JHIII and three JHAs (hydroprene, pyriproxyfen and methoprene) to induce presoldier differentiation was tested in a highly derived termite, Nasutitermes takasagoensis (Isoptera: Nasutitermitinae), and induced presoldiers were examined morphologically and histologically. Hydroprene was the most effective hormone analog for the artificial induction of presoldier differentiation. Principal component analysis showed that hydroprene-induced presoldiers had similar external gross morphology to natural presoldiers found in the same colony. Induced presoldiers had a long, horn-like frontal projection, called a nasus, on the head. A well-developed reservoir and duct of the frontal gland were also observed inside the head. Scanning electron micrographs showed that the precursory structure forming the nasus (nasus disc) was developed under the cuticle of hydroprene-treated individuals just prior to the molt into presoldiers. Morphological changes in presoldier differentiation induced by hydroprene seemed to occur normally, compared with those in natural presoldiers. Thus, the present methods shown in this study will provide opportunities to conduct further molecular analyses on the molecular developmental bases of nasus formation during soldier differentiation in higher termites.

  3. Hormones

    MedlinePlus

    Hormones are your body's chemical messengers. They travel in your bloodstream to tissues or organs. They work ... glands, which are special groups of cells, make hormones. The major endocrine glands are the pituitary, pineal, ...

  4. Alteration of thyroid hormone concentrations in juvenile Chinook salmon (Oncorhynchus tshawytscha) exposed to polybrominated diphenyl ethers, BDE-47 and BDE-99.

    PubMed

    Arkoosh, Mary R; Van Gaest, Ahna L; Strickland, Stacy A; Hutchinson, Greg P; Krupkin, Alex B; Dietrich, Joseph P

    2017-03-01

    Polybrominated diphenyl ethers (PBDEs) have been used as flame-retardants in consumer products and are currently detected in salmon globally. The two most predominant PBDE congeners found in salmon are BDE-47 (2,2',4,4'-tetrabromodiphenyl ether) and BDE-99 (2,2',4,4',5-pentabromodiphenyl ether). In the present study, groups of juvenile Pacific Chinook salmon were fed five environmentally relevant concentrations of either BDE-47 (0.3-552 ng total PBDEs/g food), BDE-99 (0.3-580 ng total PBDEs/g food), or nearly equal mixtures of both congeners (0.7-690 ng total PBDEs/g food) for 39-40 days. The concentrations of circulating total thyroid hormones, thyroxine (T4) and 3,5,3'-triiodothyronine (T3), were measured using a hormone-specific time-resolved fluoroimmunoassay to determine if PBDE exposure disrupts the hypothalamic-pituitary-thyroid endocrine axis. The concentrations of both circulating T4 and T3 were altered in juvenile salmon by dietary uptake of BDE-99. Exposure to BDE-47 did not alter either T3 or T4 circulating hormone concentrations. However, exposure to a mixture of BDE-47 and BDE-99 reduced T3 in fish with lower concentrations of total whole body PBDEs than with either congener alone at equivalent PBDE whole body concentrations. Accordingly, the disruption of PBDEs on circulating thyroid hormone concentrations has the potential to impact a number of critical functions in juvenile salmon including growth, parr-smolt transformation, and immunological processes.

  5. Examination of the influence of juvenile Atlantic salmon on the feeding mode of juvenile steelhead in Lake Ontario tributaries

    USGS Publications Warehouse

    Johnson, James H.; Waldt, Emily M.

    2014-01-01

    We examined diets of 1204 allopatric and sympatric juvenile Atlantic salmon (Salmo salar) and steelhead (Oncorhynchus mykiss) in three tributaries of Lake Ontario. The diet composition of both species consisted primarily of ephemeropterans, trichopterans, and chironomids, although juvenile steelhead consumed more terrestrial invertebrates, especially at the sympatric sites. Subyearlings of both species consumed small prey (i.e. chironomids) whereas large prey (i.e. perlids) made up a higher percentage of the diet of yearlings. The diet of juvenile steelhead at the allopatric sites was more closely associated with the composition of the benthos than with the drift, but was about equally associated with the benthos and drift at the sympatric sites. The diet of both subyearling and yearling Atlantic salmon was more closely associated with the benthos than the drift at the sympatric sites. The evidence suggests that juvenile steelhead may subtly alter their feeding behavior in sympatry with Atlantic salmon. This behavioral adaptation may reduce competitive interactions between these species.

  6. Plant-derived juvenile hormone III analogues and other sesquiterpenes from the stem bark of Cananga latifolia.

    PubMed

    Yang, Heejung; Kim, Hye Seong; Jeong, Eun Ju; Khiev, Piseth; Chin, Young-Won; Sung, Sang Hyun

    2013-10-01

    Juvenile hormone III (JH III) is a larval metamorphosis-regulating hormone present in most insect species. JH III was first isolated from the plant, Cyperus iria L., but the presence of JH III has not been reported in other plant species. In the present study, proof of the existence of JH III and its analogues from Cananga latifolia was established. From an aqueous MeOH extract of C. latifolia stem bark, six compounds were isolated along with nine known compounds. These were identified by using spectroscopic analyses as: (2E,6E,10R)-11-butoxy-10-hydroxy-3,7,11-trimethyldodeca-2,6-dienoic acid methyl ester, (2E,6E)-3,7,11-trimethyl-10-oxododeca-2,6-dienoic acid methyl ester, (2E)-3-methyl-5-[(1S,2R,6R)-1,2,6-trimethyl-3-oxocyclohexyl]-pent-2-enoic acid methyl ester, 1β-hydroxy-3-oxo-4β, 5α,7α-H-eudesmane 11-O-α-l-rhamnopyranoside, 4-epi-aubergenone 11-O-2',3'-di-O-acetyl-α-l-rhamnopyranoside and 4-epi-aubergenone 11-O-2',4'-di-O-acetyl-α-l-rhamnopyranoside. Three of the previously known compounds, (2E,6E,10R)-10-hydroxy-3,7,11-trimethyldodeca-2,6,11-trienoaic acid methyl ester, (2E,6E,10R)-10,11-dihydroxy-3,7,11-trimethyldodeca-2,6-dienoic acid and (2E,6S)-3-methyl-6-hydroxy-6-[(2R,5R)-5-(2-hydroxypropan-2-yl)-2-methyltetrahydrofuran-2-yl]-hex-2-enoaic acid methyl ester have now been found in a plant species. Ultra performance liquid chromatography-quadruple time-of-flight mass spectroscopy (UPLC-QTOF/MS) analysis of the chemical constituents of C. latifolia showed that several were predominant in the sub-fractions of a C. latifolia stem bark extract.

  7. Krüppel homolog 1 (Kr-h1) mediates juvenile hormone action during metamorphosis of Drosophila melanogaster.

    PubMed

    Minakuchi, Chieka; Zhou, Xiaofeng; Riddiford, Lynn M

    2008-01-01

    Juvenile hormone (JH) given at pupariation inhibits bristle formation and causes pupal cuticle formation in the abdomen of Drosophila melanogaster due to its prolongation of expression of the transcription factor Broad (BR). In a microarray analysis of JH-induced gene expression in abdominal integument, we found that Krüppel homolog 1 (Kr-h1) was up-regulated during most of adult development. Quantitative real-time PCR analyses showed that Kr-h1 up-regulation began at 10h after puparium formation (APF), and Kr-h1 up-regulation occurred in imaginal epidermal cells, persisting larval muscles, and larval oenocytes. Ectopic expression of Kr-h1 in abdominal epidermis using T155-Gal4 to drive UAS-Kr-h1 resulted in missing or short bristles in the dorsal midline. This phenotype was similar to that seen after a low dose of JH or after misexpression of br between 21 and 30 h APF. Ectopic expression of Kr-h1 prolonged the expression of BR protein in the pleura and the dorsal tergite. No Kr-h1 was seen after misexpression of br. Thus, Kr-h1 mediates some of the JH signaling in the adult abdominal epidermis and is upstream of br in this pathway. We also show for the first time that the JH-mediated maintenance of br expression in this epidermis is patterned and that JH delays the fusion of the imaginal cells and the disappearance of Dpp in the dorsal midline.

  8. Precocious sexual signalling and mating in Anastrepha fraterculus (Diptera: Tephritidae) sterile males achieved through juvenile hormone treatment and protein supplements.

    PubMed

    Liendo, M C; Devescovi, F; Bachmann, G E; Utgés, M E; Abraham, S; Vera, M T; Lanzavecchia, S B; Bouvet, J P; Gómez-Cendra, P; Hendrichs, J; Teal, P E A; Cladera, J L; Segura, D F

    2013-02-01

    Sexual maturation of Anastrepha fraterculus is a long process. Methoprene (a mimic of juvenile hormone) considerably reduces the time for sexual maturation in males. However, in other Anastrepha species, this effect depends on protein intake at the adult stage. Here, we evaluated the mating competitiveness of sterile laboratory males and females that were treated with methoprene (either the pupal or adult stage) and were kept under different regimes of adult food, which varied in the protein source and the sugar:protein ratio. Experiments were carried out under semi-natural conditions, where laboratory flies competed over copulations with sexually mature wild flies. Sterile, methoprene-treated males that reached sexual maturity earlier (six days old), displayed the same lekking behaviour, attractiveness to females and mating competitiveness as mature wild males. This effect depended on protein intake. Diets containing sugar and hydrolyzed yeast allowed sterile males to compete with wild males (even at a low concentration of protein), while brewer´s yeast failed to do so even at a higher concentration. Sugar only fed males were unable to achieve significant numbers of copulations. Methoprene did not increase the readiness to mate of six-day-old sterile females. Long pre-copulatory periods create an additional cost to the management of fruit fly pests through the sterile insect technique (SIT). Our findings suggest that methoprene treatment will increase SIT effectiveness against A. fraterculus when coupled with a diet fortified with protein. Additionally, methoprene acts as a physiological sexing method, allowing the release of mature males and immature females and hence increasing SIT efficiency.

  9. Comparative ovarian microarray analysis of juvenile hormone-responsive genes in water flea Daphnia magna: potential targets for toxicity.

    PubMed

    Toyota, Kenji; Williams, Timothy D; Sato, Tomomi; Tatarazako, Norihisa; Iguchi, Taisen

    2017-03-01

    The freshwater zooplankton Daphnia magna has been extensively employed in chemical toxicity tests such as OECD Test Guidelines 202 and 211. Previously, it has been demonstrated that the treatment of juvenile hormones (JHs) or their analogues to female daphnids can induce male offspring production. Based on this finding, a rapid screening method for detection of chemicals with JH-activity was recently developed using adult D. magna. This screening system determines whether a chemical has JH-activity by investigating the male offspring inducibility. Although this is an efficient high-throughput short-term screening system, much remains to be discovered about JH-responsive pathways in the ovary, and whether different JH-activators act via the same mechanism. JH-responsive genes in the ovary including developing oocytes are still largely undescribed. Here, we conducted comparative microarray analyses using ovaries from Daphnia magna treated with fenoxycarb (Fx; artificial JH agonist) or methyl farnesoate (MF; a putative innate JH in daphnids) to elucidate responses to JH agonists in the ovary, including developing oocytes, at a JH-sensitive period for male sex determination. We demonstrate that induction of hemoglobin genes is a well-conserved response to JH even in the ovary, and a potential adverse effect of JH agonist is suppression of vitellogenin gene expression, that might cause reduction of offspring number. This is the first report demonstrating different transcriptomics profiles from MF and an artificial JH agonist in D. magna ovary, improving understanding the tissue-specific mode-of-action of JH. Copyright © 2016 John Wiley & Sons, Ltd.

  10. Juvenile hormone biosynthesis, oocyte growth and vitellogenin accumulation in Choristoneura fumiferana and C. rosaceana: a comparative study.

    PubMed

    Delisle, J; Cusson, M

    1999-06-01

    We assessed the effects of age and mating status on in vitro juvenile hormone (JH) biosynthesis, oocyte growth, egg production and vitellogenin (Vg) accumulation in the tortricid moths, Choristoneura fumiferana and C. rosaceana. To determine whether vitellogenesis is dependent on the presence of JH, we also examined the effects of decapitation and JH analog treatments on egg production. In both species, the corpora allata (CA) of adult females released fmol quantities of JH, with JH II being the major homolog produced. The CA began producing detectable quantities of JH around the time of emergence. Full activation of the CA was observed a few hours sooner in C. fumiferana than in C. rosaceana. In pharate adults and young virgin females of both species, growth of the basal oocyte reflected changes in CA activity. Decapitation of newly emerged females significantly reduced egg production, but treatment of decapitated females with the JH analog methoprene resulted in egg production that was similar to (C. fumiferana) or greater than (C. rosaceana) that of controls, indicating that JH is required for oocyte maturation. Vg was first observed in the hemolymph before the presumptive time of CA activation, suggesting that the synthesis of this protein is not dependent on JH. The presence of normal quantities of Vg in the hemolymph of pupae decapitated before CA activation confirmed this hypothesis. The Vg titer underwent a transient decline following CA activation and was significantly lower in mated than in virgin females of both species 3 and 5 days after copulation. Since CA activation at emergence and mating are both expected to cause a rise in the JH titer, we suggest that the declines in the levels of Vg result from JH-enhanced Vg uptake by the developing oocytes. Mating induced a significant increase in egg production but had no measurable impact on rates of JH biosynthesis in vitro.

  11. Functional significance of parasitism-induced suppression of juvenile hormone esterase activity in developmentally delayed Choristoneura fumiferana larvae.

    PubMed

    Cusson, M; Laforge, M; Miller, D; Cloutier, C; Stoltz, D

    2000-03-01

    The parasitic wasp Tranosema rostrale transmits a polydnavirus (PDV) to its host, Choristoneura fumiferana, during oviposition. Last-instar C. fumiferana larvae parasitized by T. rostrale early in the stadium fail to undergo metamorphosis, and injection of the wasp's calyx fluid (CxF; contains PDV) into healthy caterpillars induces a dose-dependent delay in initiation of metamorphosis (D. Doucet and M. Cusson, 1996, Entomol. Exp. Appl. 81, 21-30). In the present work, parasitization and injection of CxF (0.5 female equivalent) on the first day of the last stadium both prevented the rise in hemolymph 20-hydroxyecdysone (20HE) titer observed between day 4 and day 7 in control and saline-injected larvae. Similarly, juvenile hormone esterase (JHE) activity was depressed following parasitization or CxF injection, whereas control larvae displayed a peak on day 4. However, neither parasitism nor injection of CxF on day 1 prevented the JH-producing glands from turning off during the first half of the last stadium. Likewise, low but clearly detectable JH titers were observed in the first hours following the molt but very low titers, at or near the detection limit of our radioimmunoassay, were seen in both control and parasitized larvae on day 4. Prothoracic glands showed no apparent sign of degeneration 4 days after injection of CxF but had significantly smaller cells than saline-injected larvae 7 days postinjection. It is not clear whether this was a direct effect of T. rostrale PDV. Thus, disruption of spruce budworm metamorphosis by T. rostrale CxF involves depression of 20HE titers but is not associated with a measurable increase in the level of JH, as shown for some other host-parasitoid systems. In view of the latter observation, we put forward three hypotheses regarding the functional significance of the observed suppression of JHE activity in developmentally arrested C. fumiferana larvae.

  12. CHARACTERIZATION AND FUNCTIONAL STUDY OF A PUTATIVE JUVENILE HORMONE DIOL KINASE IN THE COLORADO POTATO BEETLE Leptinotarsa decemlineata (Say).

    PubMed

    Fu, Kai-Yun; Lü, Feng-Gong; Guo, Wen-Chao; Li, Guo-Qing

    2015-11-01

    Juvenile hormone diol kinase (JHDK) is an enzyme involved in JH degradation. In the present article, a putative JHDK cDNA (LdJHDK) was cloned from the Colorado potato beetle Leptinotarsa decemlineata. The cDNA consists of 814 bp, containing a 555 bp open reading frame encoding a 184 amino acid protein. LdJHDK reveals a high degree of identity to the previously reported insect JHDKs. It possesses three conserved purine nucleotide-binding elements, and contains three EF-hand motifs (helix-loop-helix structural domains). LdJHDK mRNA was mainly detected in hindgut and Malpighian tubules. Besides, a trace amount of LdJHDK mRNA was also found in thoracic muscles, brain-corpora cardiaca-corpora allata complex, foregut, midgut, ventral ganglia, fat body, epidermis, and hemocytes. Moreover, LdJHDK was expressed throughout all developmental stages. Within the first, second, and third larval instar, the expression levels of LdJHDK were higher just before and right after the molt, and were lower in the intermediate instar. In the fourth larval instar, the highest peak of LdJHDK occurred 56 h after ecdysis. Ingestion of double-stranded RNA (dsRNA) against LdJHDK successfully knocked down the target gene, increased JH titer, and significantly upregulated LdKr-h1 mRNA level. Knockdown of LdJHDK significantly impaired adult emergence. Thus, we provide a line of experimental evidence in L. decemlineata to support that LdJHDK encodes function protein involved in JH degradation. © 2015 Wiley Periodicals, Inc.

  13. Developmental link between sex and nutrition; doublesex regulates sex-specific mandible growth via juvenile hormone signaling in stag beetles.

    PubMed

    Gotoh, Hiroki; Miyakawa, Hitoshi; Ishikawa, Asano; Ishikawa, Yuki; Sugime, Yasuhiro; Emlen, Douglas J; Lavine, Laura C; Miura, Toru

    2014-01-01

    Sexual dimorphisms in trait expression are widespread among animals and are especially pronounced in ornaments and weapons of sexual selection, which can attain exaggerated sizes. Expression of exaggerated traits is usually male-specific and nutrition sensitive. Consequently, the developmental mechanisms generating sexually dimorphic growth and nutrition-dependent phenotypic plasticity are each likely to regulate the expression of extreme structures. Yet we know little about how either of these mechanisms work, much less how they might interact with each other. We investigated the developmental mechanisms of sex-specific mandible growth in the stag beetle Cyclommatus metallifer, focusing on doublesex gene function and its interaction with juvenile hormone (JH) signaling. doublesex genes encode transcription factors that orchestrate male and female specific trait development, and JH acts as a mediator between nutrition and mandible growth. We found that the Cmdsx gene regulates sex differentiation in the stag beetle. Knockdown of Cmdsx by RNA-interference in both males and females produced intersex phenotypes, indicating a role for Cmdsx in sex-specific trait growth. By combining knockdown of Cmdsx with JH treatment, we showed that female-specific splice variants of Cmdsx contribute to the insensitivity of female mandibles to JH: knockdown of Cmdsx reversed this pattern, so that mandibles in knockdown females were stimulated to grow by JH treatment. In contrast, mandibles in knockdown males retained some sensitivity to JH, though mandibles in these individuals did not attain the full sizes of wild type males. We suggest that moderate JH sensitivity of mandibular cells may be the default developmental state for both sexes, with sex-specific Dsx protein decreasing sensitivity in females, and increasing it in males. This study is the first to demonstrate a causal link between the sex determination and JH signaling pathways, which clearly interact to determine the

  14. Developmental Link between Sex and Nutrition; doublesex Regulates Sex-Specific Mandible Growth via Juvenile Hormone Signaling in Stag Beetles

    PubMed Central

    Gotoh, Hiroki; Miyakawa, Hitoshi; Ishikawa, Asano; Ishikawa, Yuki; Sugime, Yasuhiro; Emlen, Douglas J.; Lavine, Laura C.; Miura, Toru

    2014-01-01

    Sexual dimorphisms in trait expression are widespread among animals and are especially pronounced in ornaments and weapons of sexual selection, which can attain exaggerated sizes. Expression of exaggerated traits is usually male-specific and nutrition sensitive. Consequently, the developmental mechanisms generating sexually dimorphic growth and nutrition-dependent phenotypic plasticity are each likely to regulate the expression of extreme structures. Yet we know little about how either of these mechanisms work, much less how they might interact with each other. We investigated the developmental mechanisms of sex-specific mandible growth in the stag beetle Cyclommatus metallifer, focusing on doublesex gene function and its interaction with juvenile hormone (JH) signaling. doublesex genes encode transcription factors that orchestrate male and female specific trait development, and JH acts as a mediator between nutrition and mandible growth. We found that the Cmdsx gene regulates sex differentiation in the stag beetle. Knockdown of Cmdsx by RNA-interference in both males and females produced intersex phenotypes, indicating a role for Cmdsx in sex-specific trait growth. By combining knockdown of Cmdsx with JH treatment, we showed that female-specific splice variants of Cmdsx contribute to the insensitivity of female mandibles to JH: knockdown of Cmdsx reversed this pattern, so that mandibles in knockdown females were stimulated to grow by JH treatment. In contrast, mandibles in knockdown males retained some sensitivity to JH, though mandibles in these individuals did not attain the full sizes of wild type males. We suggest that moderate JH sensitivity of mandibular cells may be the default developmental state for both sexes, with sex-specific Dsx protein decreasing sensitivity in females, and increasing it in males. This study is the first to demonstrate a causal link between the sex determination and JH signaling pathways, which clearly interact to determine the

  15. Juvenile Hormone Differentially Regulates Two Grp78 Genes Encoding Protein Chaperones Required for Insect Fat Body Cell Homeostasis and Vitellogenesis.

    PubMed

    Luo, Maowu; Li, Dong; Wang, Zhiming; Guo, Wei; Kang, Le; Zhou, Shutang

    2017-03-29

    Juvenile hormone (JH) has a well-known role in stimulating insect vitellogenesis (i.e. yolk deposition) and oocyte maturation, but the molecular mechanisms of JH action in insect reproduction are unclear. Glucose-regulated protein of 78 kDa (Grp78) is a heat shock protein 70 kDa family member and one of the most abundant chaperones in the endoplasmic reticulum (ER) where it helps fold newly synthesized peptides. Because of its prominent role in protein folding and also ER stress, we hypothesized that Grp78 might be involved in fat body cell homeostasis and vitellogenesis and a regulatory target of JH. We report here that the migratory locust Locusta migratoria possesses two Grp78 genes that are differentially regulated by JH. We found that Grp78-1 is regulated by JH through Mcm4/7-dependent DNA replication and polyploidization, whereas Grp78-2 expression is directly activated by the JH-receptor complex comprising Methoprene-tolerant and Taiman proteins. Interestingly, Grp78-2 expression in the fat body is about 10-fold higher than that of Grp78-1 Knockdown of either Grp78-1 or Grp78-2 significantly reduced levels of vitellogenin (Vg) protein, accompanied by retarded maturation of oocytes. Depletion of both Grp78-1 and Grp78-2 resulted in ER stress and apoptosis in the fat body and in severely defective Vg synthesis and oocyte maturation. These results indicate a crucial role of Grp78 in JH-dependent vitellogenesis and egg production. The presence and differential regulation of two Grp78 genes in L. migratoria likely help accelerate the production of this chaperone in the fat body to facilitate folding of massively synthesized Vg and other proteins.

  16. Expressional and functional analysis of CYP15A1, a juvenile hormone epoxidase, in the red flour beetle Tribolium castaneum.

    PubMed

    Minakuchi, Chieka; Ishii, Fumika; Washidu, Yumiko; Ichikawa, Akio; Tanaka, Toshiharu; Miura, Ken; Shinoda, Tetsuro

    2015-09-01

    Juvenile hormone (JH) is synthesized and secreted by the corpora allata. In the final two steps of JH biosynthesis, farnesoic acid (FA) is converted to JH through methylation by JH acid O-methyltransferase (JHAMT) and epoxidation by the cytochrome P450 enzyme CYP15. In the present study, we identified a homolog of CYP15 from the red flour beetle Tribolium castaneum (TcCYP15A1), and analyzed its expression as well as its role in JH biosynthesis. Quantitative RT-PCR analysis showed that the level of TcCYP15A1 mRNA was high in the embryonic stage as well as in the middle of the final larval instar. In the embryonic stage, the transcript level of TcCYP15A1 started to increase 30h after egg laying (AEL), peaked 54-60h AEL, and was followed by an increase of TcJHAMT mRNA, suggesting that JH biosynthesis started at this time point. TcCYP15A1 mRNA was present, but not exclusively so in the larval corpora allata. The recombinant TcCYP15A1 protein epoxidized both FA and methyl farnesoate (MF) in highly stereo-specific manners. These results confirmed that TcCYP15A1 is involved in JH biosynthesis. The RNAi-mediated knockdown of TcCYP15A1 in the pre-final larval instar did not result in precocious metamorphosis to pupa, indicating that MF may exhibit JH-like activity in order to maintain the larval status. The double knockdown of TcJHAMT and TcCYP15A1 resulted in pupae and adults with shorter wings, suggesting that the precursors of JH, JH acid and MF, may be essential for wing expansion.

  17. Sex differences in juvenile mouse social behavior are influenced by sex chromosomes and social context

    PubMed Central

    Cox, Kimberly H.; Rissman, Emilie F.

    2011-01-01

    Play behavior in juvenile primates, rats, and other species is sexually dimorphic, with males demonstrating more play than females. In mice, sex differences in juvenile play have only been examined in out-bred CD-1 mice. In this strain, contrary to other animals, male mice display less play soliciting than females. Using an established same-sex dyadic interaction test, we examined play in inbred C57BL/6J (B6) 21 day-old mice. When paired with non-siblings, males tended to be more social than females, spending more time exploring the test cage. Females displayed significantly more anogenital sniffing and solicited play more frequently than did males. To determine if the origin of the sex difference was sex chromosome genes or gonadal sex, next we used the four core genotype (FCG) mouse. We found significant interactions between gonadal sex and genotype for several behaviors. Finally, we asked if sibling pairs (as compared to non-siblings) would display qualitative or quantitatively different behavior. In fact, XX females paired with a sibling were more social and less exploratory or investigative, while XY males exhibited less investigative and play soliciting behaviors in tests with siblings. Many neurobehavioral disorders, like autism spectrum disorder (ASD), are sexually dimorphic in incidence and patients interact less than normal with other children. Our results suggest that sex chromosome genes interact with gonadal hormones to shape the development of juvenile social behavior, and that social context can drastically alter sex differences. These data may have relevance for understanding the etiology of sexually dimorphic disorders such as ASD. PMID:21414140

  18. Influence of environment on walleye pollock eggs, larvae, and juveniles in the southeastern Bering Sea

    NASA Astrophysics Data System (ADS)

    Smart, Tracey I.; Duffy-Anderson, Janet T.; Horne, John K.; Farley, Edward V.; Wilson, Christopher D.; Napp, Jeffrey M.

    2012-06-01

    We examined the influence of environmental conditions on walleye pollock (Theragra chalcogramma) early life history in discrete stages at two ecological scales using a 17-year time series from the southeastern Bering Sea. Generalized additive models (GAMs) were used to quantify relationships between walleye pollock stages (eggs, yolksac larvae, preflexion larvae, late larvae, and juveniles), the fine-resolution environment (temperature, wind speed, salinity, and copepod concentration), and the broad-resolution environment (annual spawning stock biomass, temperature, zooplankton biomass, and wind mixing). Early stages (eggs, yolksac larvae, and preflexion larvae) were associated with high spawning stock biomass, while late stages (late larvae and juveniles) were not associated with spawning stock biomass. The influence of temperature increased with ontogeny: high egg abundance was associated with temperatures from -2 to 7 °C and negative annual temperature anomalies and high juvenile abundance was associated with temperatures from 4 to 12 °C and positive temperature anomalies. Winds enhanced the transport of early stages from spawning locations to shallower sampling depths, but did not affect feeding stages (preflexion larvae, late larvae, and juveniles) in a manner consistent with the encounter-turbulence hypothesis. Feeding stages were positively associated with localized copepod concentrations but not zooplankton biomass anomaly, suggesting that the localized measurements of potential prey is a better indicator compared to broad-scale conditions measured in areas where these stages do not necessarily occur. Broad-resolution covariates, however, explained a greater portion of the overall variation than did fine-resolution models. Of the environmental conditions examined, temperature explained more variation in abundance of walleye pollock early life stages than any other covariate. Temperature is likely a major driving force structuring variability in

  19. Cyp15F1: a novel cytochrome P450 gene linked to juvenile hormone-dependent caste differention in the termite Reticulitermes flavipes.

    PubMed

    Tarver, Matthew R; Coy, Monique R; Scharf, Michael E

    2012-07-01

    Termites are eusocial insects that jointly utilize juvenile hormone (JH), pheromones, and other semiochemicals to regulate caste differentiation and achieve caste homeostasis. Prior EST sequencing from the symbiont-free gut transcriptome of Reticulitermes flavipes unexpectedly revealed a number of unique cytochrome P450 (Cyp) transcripts, including fragments of a Cyp15 family gene (Cyp15F1) with homology to other insect Cyp15s that participate in JH biosynthesis. The present study investigated the role of Cyp15F1 in termite caste polyphenism and specifically tested the hypothesis that it plays a role in JH-dependent caste differentiation. After assembling the full-length Cyp15F1 cDNA sequence, we (i) determined its mRNA tissue expression profile, (ii) investigated mRNA expression changes in response to JH and the caste-regulatory primer pheromones γ-cadinene (CAD) and γ-cadinenal (ALD), and (iii) used RNA interference (RNAi) in combination with caste differentiation bioassays to investigate gene function at the phenotype level. Cyp15F1 has ubiquitous whole-body expression (including gut tissue); is rapidly and sustainably induced from 3 h to 48 h by JH, CAD, and ALD; and functions at least in part by facilitating JH-dependent soldier caste differentiation. These findings provide the second example of a termite caste regulatory gene identified through the use of RNAi, and significantly build upon our understanding of termite caste homeostatic mechanisms. These results also reinforce the concept of environmental caste determination in termites by revealing how primer pheromones, as socioenvironmental factors, can directly influence Cyp15 expression and caste differentiation.

  20. The effect of the juvenile hormone analog, fenoxycarb, on ecdysone receptor B1 expression in the midgut of Bombyx mori during larval-pupal metamorphosis.

    PubMed

    Goncu, Ebru; Parlak, Osman

    2012-04-24

    The Bombyx mori (Lepidoptera: Bombycidae) midgut undergoes remodeling during the larval-pupal metamorphosis. All metamorphic events in insects are controlled by mainly two hormones: 20-hydroxyecdysone (20E) and juvenile hormone (JH). Fenoxycarb, O-ethyl N-(2-(4-phenoxyphenoxy)-ethyl) carbamate, has been shown to be one of the most potent juvenile hormone analogs against a variety of insect species. In this study, the effect of fenoxycarb on EcR-B1 protein expression in the midgut of Bombyx mori during the remodeling processwas investigated. Fenoxycarb was topically treated to the beginning of the fifth instar Bombyx larvae. Its application prolonged the last instar and prevented metamorphic events. Analyses were performed from day 6 of the fifth instar to 24 hr after pupation in controls and to day 14 of the fifth instar in the fenoxycarb treated group. According to our results, the presence of EcR-B1 in the midguts of the fenoxycarb treated group during the feeding period suggested that EcR-B1 was involved in the functioning of larval cells and during this period fenoxycarb did not affect EcR-B1 status. Immediately after termination of the feeding stage, the amount of EcR-B1 protein increased, which indicated that it may strengthen the ecdysone signal for commitment of remodeling process. In the fenoxycarb treated group, its upregulation was delayed, which may be related to the inhibition of ecdysone secretion from the prothoracic gland.

  1. Hypermetabolic Conversion of Plant Oil into Water: Endothermic Biochemical Process Stimulated by Juvenile Hormone in the European Firebug, Pyrrhocoris apterus L.

    PubMed

    Sláma, Karel; Lukáš, Jan

    2016-01-01

    The physiological and biochemical mechanisms that enable insects to feed on dry food to secure enough water for larval growth were investigated. The study was carried out with a plethora of physiological methods, ranging from the simple volumetric determination of O2 consumption and water intake to more advanced methods such as scanning microrespirography and thermovision imaging of insect's body temperature. The experiments were done on the European firebug, Pyrrhocoris apterus, which feeds exclusively on dry linden seeds. In order to survive, it needs to drink water or suck a sap from plants occasionally. It was found that the young larval instars compensate the occasional water deficiency by the increased production of metabolic water. The juvenile hormone (JH)-dependent production of metabolic water, which was previously found in other species consuming dry food, was achieved in P. apterus by total metabolic combustion of the dietary lipid (neutral seed oil). The water-producing, hypermetabolic larvae were heated from inside by endothermic energy released from the uncoupling of oxidation from oxidative phosphorylation. The "warm", hypermetabolic larvae burning the dietary oil into CO2 and water showed the increased rates of respiratory metabolism. Microrespirographic recording of these larvae revealed the ratio of the respiratory quotient (RQ, CO2/O2) of 0.7, which indicated the breakdown of a pure triglyceride. The warm hypermetabolic larvae could be easily spotted and distinguished from the "cold" larvae on the screen of a thermovision camera. The last instar larvae lacking the JH were always only cold. They metabolized a carbohydrate substrate exclusively (RQ = 1.0), while the dietary lipid was stored in the fat body. In comparison with the hypermetabolic larvae of some other species fed on dry food, which exhibited the highest rates of O2 consumption ever recorded in a living organism (10-20 mL O2/g per hour), the metabolic difference between the warm and

  2. The influence of stress hormones on fear circuitry.

    PubMed

    Rodrigues, Sarina M; LeDoux, Joseph E; Sapolsky, Robert M

    2009-01-01

    Fear arousal, initiated by an environmental threat, leads to activation of the stress response, a state of alarm that promotes an array of autonomic and endocrine changes designed to aid self-preservation. The stress response includes the release of glucocorticoids from the adrenal cortex and catecholamines from the adrenal medulla and sympathetic nerves. These stress hormones, in turn, provide feedback to the brain and influence neural structures that control emotion and cognition. To illustrate this influence, we focus on how it impacts fear conditioning, a behavioral paradigm widely used to study the neural mechanisms underlying the acquisition, expression, consolidation, reconsolidation, and extinction of emotional memories. We also discuss how stress and the endocrine mediators of the stress response influence the morphological and electrophysiological properties of neurons in brain areas that are crucial for fear-conditioning processes, including the amygdala, hippocampus, and prefrontal cortex. The information in this review illuminates the behavioral and cellular events that underlie the feedforward and feedback networks that mediate states of fear and stress and their interaction in the brain.

  3. Infection by the microsporidium Vairimorpha necatrix (Microspora: Microsporidia) elevates juvenile hormone titres in larvae of the tomato moth, Lacanobia oleracea (Lepidoptera: Noctuidae).

    PubMed

    Down, Rachel E; Bell, Howard A; Bryning, Gareth; Kirkbride-Smith, Anne E; Edwards, John P; Weaver, Robert J

    2008-03-01

    The effects of infection by a microsporidium, Vairimorpha necatrix (Kramer), on the endogenous levels of juvenile hormones in tomato moth (Lacanobia oleracea L.) larvae were investigated. Levels of juvenile hormone II (JH II) were 10-fold greater in the infected larvae on day two of the sixth stadium but no significant difference was observed on day seven. Juvenile hormone I (JH I) was also detected in day two and day seven sixth instar infected larvae but was not detected in non-infected larvae. The duration of the fifth and sixth stadia was significantly longer for infected larvae when compared with non-infected larvae. No evidence was found to suggest that supernumerary moults are a feature of infection by V. necatrix in L. oleracea larvae. Experiments were performed to determine whether the elevation in JH levels, which probably prevents pupation, is an adaptive mechanism of the microsporidium for extending the growth phase of the host, thereby allowing increased spore production. A proportion of infected larvae were collected on days 9 and 24 of the sixth stadium and spore extracts prepared from each larva. These days represent the average duration of the sixth stadium required for uninfected larvae to reach pupation, and the average number of days that V. necatrix-infected larvae survive in the sixth stadium before dying from infection. The mean spore yields from infected larvae 24 days into the sixth stadium were significantly higher than the spore yields obtained from day nine sixth instar larvae. The hypothesis that V. necatrix manipulates host endocrinology (i.e. prolong the host larval state to maximise spore yield) is discussed in context with the results obtained.

  4. Youth pathways to placement: the influence of gender, mental health need and trauma on confinement in the juvenile justice system.

    PubMed

    Espinosa, Erin M; Sorensen, Jon R; Lopez, Molly A

    2013-12-01

    Although the juvenile crime rate has generally declined, the involvement of girls in the juvenile justice system has been increasing. Possible explanations for this gender difference include the impact of exposure to trauma and mental health needs on developmental pathways and the resulting influence of youth's involvement in the justice system. This study examined the influence of gender, mental health needs and trauma on the risk of out-of-home placement for juvenile offenders. The sample included youth referred to three urban juvenile probation departments in Texas between January 1, 2007 and December 31, 2008 and who received state-mandated mental health screening (N = 34,222; 30.1 % female). The analysis revealed that, for both genders, elevated scores on the seven factor-analytically derived subscales of a mental health screening instrument (Alcohol and Drug Use, Depressed-Anxious, Somatic Complaints, Suicidal Ideation, Thought Disturbance, and Traumatic Experiences), especially related to past traumatic experiences, influenced how deeply juveniles penetrated the system. The findings suggest that additional research is needed to determine the effectiveness of trauma interventions and the implementation of trauma informed systems for youth involved with the juvenile justice system.

  5. Family-specific differences in growth rate and hepatic gene expression in juvenile triploid growth hormone (GH) transgenic Atlantic salmon (Salmo salar).

    PubMed

    Xu, Qingheng; Feng, Charles Y; Hori, Tiago S; Plouffe, Debbie A; Buchanan, John T; Rise, Matthew L

    2013-12-01

    Growth hormone transgenic (GHTg) Atlantic salmon (Salmo salar) have enhanced growth when compared to their non-transgenic counterparts, and this trait can be beneficial for aquaculture production. Biological confinement of GHTg Atlantic salmon may be achieved through the induction of triploidy (3N). The growth rates of triploid GH transgenic (3NGHTg) Atlantic salmon juveniles were found to significantly vary between families in the AquaBounty breeding program. In order to characterize gene expression associated with enhanced growth in juvenile 3NGHTg Atlantic salmon, a functional genomics approach (32K cDNA microarray hybridizations followed by QPCR) was used to identify and validate liver transcripts that were differentially expressed between two fast-growing 3NGHTg Atlantic salmon families (AS11, AS26) and a slow-growing 3NGHTg Atlantic salmon family (AS25); juvenile growth rate was evaluated over a 45-day period. Of 687 microarray-identified differentially expressed features, 143 (116 more highly expressed in fast-growing and 27 more highly expressed in slow-growing juveniles) were identified in the AS11 vs. AS25 microarray study, while 544 (442 more highly expressed in fast-growing and 102 more highly expressed in slow-growing juveniles) were identified in the AS26 vs. AS25 microarray study. Forty microarray features (39 putatively associated with fast growth and 1 putatively associated with slow growth) were present in both microarray experiment gene lists. The expression levels of 15 microarray-identified transcripts were studied using QPCR with individual RNA samples to validate microarray results and to study biological variability of transcript expression. The QPCR results agreed with the microarray results for 12 of 13 putative fast-growth associated transcripts, but QPCR did not validate the microarray results for 2 putative slow-growth associated transcripts. Many of the 39 microarray-identified genes putatively associated at the transcript expression

  6. HORMONAL INFLUENCES ON MAMMARY TUMORS OF THE RAT

    PubMed Central

    Huggins, Charles; Mainzer, Klaus

    1957-01-01

    Many members of the androstane series profoundly retarded the growth of a transplanted benign mammary fibroadenoma of the rat; the restraint of tumor growth was in direct proportion to the amount of the administered compound until its maximal effect was achieved. Certain steroids closely related to the androstane inhibitors accelerated the growth of the tumor. These effects of divergent sort depend on the molecular structure of the steroid. The molecular structure of androstane derivatives, which is of high significance in modifying the rate of growth of the benign mammary tumor, consists of multiple components. These include (a) the presence and number of ketone and hydroxyl groups in special orientation at specific sites, (b) the sites of dehydrogenation in the molecule, and (c) the presence, number, and state of hydrogenation of alkyl groups at designated molecular positions. These multiple factors determine whether androstane compounds will inhibit growth of the tumor, enhance it, or fail to influence its growth. The androstane compounds which caused either the restraint or the promotion of tumor growth had the common property of inducing proliferation of the normal mammary epithelium. Two mechanisms are involved in the restraint of growth of mammary fibroadenoma by androstane inhibitors. The primary effect is the abolition of action of phenolic estrogens and progesterone when dihydrotestosterone is administered concurrently, presumably through direct action at the tumor cell level A secondary contributory suppressive effect is the depression of ovarian activity, and consequently of the production of phenolic estrogens and progesterone, by these compounds. Transplanted mammary fibroadenoma in the rat possesses neoplastic traits and also some growth properties of normal mammary epithelium; inhibition of these latter by hormonal methods commonly retarded the growth of the tumor. But in hypophysectomized rats dihydrotestosterone failed to inhibit the growth of a

  7. Synthesis of analogs of juvenile hormone on the basis of the telomerization reaction of piperylene with sulfones

    SciTech Connect

    Tolstikov, G.A.; Rozentsvet, O.A.; Pantukh, B.I.; Khalilov, L.M.

    1986-10-20

    In continuing the work on the study of the telomerization of 1,3-dienes with sulfones containing an active H atom, and also with the aim of synthesizing analogs of juvenile hormone (JH) based on the telomers obtained, they studied the catalytic telomerization of 1,3-pentadiene (piperylene) with ..beta..-substituted sulfonates. It was established that trans-piperlyene participates in the telomerization reaction with sulfones in the presence of the catalytic system PdCl/sub 2/(Ph/sub 3/P)/sub 2/-PhONa. Methyl 2-phenylsulfonyl-3,7-dimethyl-4(E), 9-decadienecarboxylate (II) is formed in a yield of 65% by the reaction of methyl phenylsulfonylacetate (I) with piperylene in the course of 20 h at 85/sup 0/C. The presence of absorption bands at 920 (CH/sub 2/=C) and 980 cm/sup -1/ (E-CH=CH) in the IR spectrum of compound (II) and the presence of a group of multiplet signals at delta 4.8-5.3 ppm in the PMR spectrum, corresponding to five protons of double bonds, indicate the addition of two molecules of piperylene to the molecule of the sulfone (I). The oxidation with oxygen on a Pd/Cu-catalyst proceeds smoothly to the methyl ketone (III); this clearly confirms the presence of the terminal C=C bond in the telomer (II). In the PMR spectrum of (II), notice is taken of the group of signals in the region of 3.30-3.53 ppm corresponding to three methoxy protons. There are three pairs of doublets (J = 7 Hz) in the region of 0.1-1.3 ppm which correspond to the methyl group. The complexity of the PMR spectrum is probably explained by the fact that the reaction leads to the formation of a complex mixture of diastereoisomers. As was to be expected, methyl 3,7-dimethyl-4,9-decadienoate (IV) is formed as the sole product with a yield of 70% in the desulfonation of the telomer (II) using Na/Hg in methanol according to the method of (5); the structure of (IV) was established with the aid of /sup 13/C NMR spectroscopy.

  8. A coordinated expression of biosynthetic enzymes controls the flux of juvenile hormone precursors in the corpora allata of mosquitoes.

    PubMed

    Nouzova, Marcela; Edwards, Marten J; Mayoral, Jaime G; Noriega, Fernando G

    2011-09-01

    Juvenile hormone (JH) is a key regulator of metamorphosis and ovarian development in mosquitoes. Adult female Aedes aegypti mosquitoes show developmental and dynamically regulated changes of JH synthesis. Newly emerged females have corpora allata (CA) with low biosynthetic activity, but they produce high amounts of JH a day later; blood feeding results in a striking decrease in JH synthesis, but the CA returns to a high level of JH synthesis three days later. To understand the molecular bases of these dynamic changes we combined transcriptional studies of 11 of the 13 enzymes of the JH pathway with a functional analysis of JH synthesis. We detected up to a 1000-fold difference in the levels of mRNA in the CA among the JH biosynthetic enzymes studied. There was a coordinated expression of the 11 JH biosynthetic enzymes in female pupae and adult mosquito. Increases or decreases in transcript levels for all the enzymes resulted in increases or decreases of JH synthesis; suggesting that transcript changes are at least partially responsible for the dynamic changes of JH biosynthesis observed. JH synthesis by the CA was progressively increased in vitro by addition of exogenous precursors such as geranyl-diphosphate, farnesyl-diphosphate, farnesol, farnesal and farnesoic acid. These results suggest that the supply of these precursors and not the activity of the last 6 pathway enzymes is rate limiting in these glands. Nutrient reserves play a key role in the regulation of JH synthesis. Nutritionally deficient females had reduced transcript levels for the genes encoding JH biosynthetic enzymes and reduced JH synthesis. Our studies suggest that JH synthesis is controlled by the rate of flux of isoprenoids, which is the outcome of a complex interplay of changes in precursor pools, enzyme levels and external regulators such as nutrients and brain factors. Enzyme levels might need to surpass a minimum threshold to achieve a net flux of precursors through the biosynthetic

  9. Sexual difference in juvenile-hormone titer in workers leads to sex-biased soldier differentiation in termites.

    PubMed

    Toga, Kouhei; Hanmoto, Shutaro; Suzuki, Ryutaro; Watanabe, Dai; Miura, Toru; Maekawa, Kiyoto

    2016-04-01

    In termites, the soldier caste, with its specialized defensive morphology, is one of the most important characteristics for sociality. Most of the basal termite species have both male and female soldiers, and the soldier sex ratio is almost equal or only slightly biased. However, in the apical lineages (especially family Termitidae), there are many species that have soldiers with strongly biased sex ratio. Generally in termites, since high juvenile hormone (JH) titer is required for soldier differentiation from a worker via a presoldier stage, it was hypothesized that the biased soldier-sex ratio was caused by differences in JH sensitivity and/or JH titer between male and female workers. Therefore, we focused on the presoldier differentiation and the worker JH titer in species with only male soldiers (Nasutitermes takasagoensis) and with both male and female soldiers (Reticulitermes speratus) in natural conditions. In the former species, there are four types of workers; male minor, male medium, female medium and female major workers, and presoldiers differentiate from male minor workers. First, we tried to artificially induce presoldiers from male and female workers. In N. takasagoensis, the presoldier differentiation rate and mortality was significantly higher in male minor workers. Morphological analyses showed that both male and female induced presoldiers possessed normal soldier-specific morphologies. It was suggested that female workers, from which soldiers do not differentiate under natural conditions, also maintained the physiological and developmental potential for soldier differentiation. In R. speratus, however, no differences were observed in solder differentiation rate and mortality between male and female workers. Second, the JH titers of each sex/type of workers were quantified by high performance liquid chromatography-mass spectrometry in two different seasons (April and December). The results showed that, in N. takasagoensis, JH titer in male minor

  10. Influence of Selected Plant Species on Hatching of Eggs and Development of Juveniles of Heterodera glycines

    PubMed Central

    Schmitt, D. P.; Riggs, R. D.

    1991-01-01

    The influence of selected plant species on egg hatch and subsequent development of Heterodera glycines race 3 was investigated. Plants tested included four soybean cultivars, red clover, alfalfa, hairy vetch, field corn, sweet corn, cabbage, tobacco, cotton, and wheat. Soybean stimulated egg hatching more than any of the other plant species, with H. glycines-resistant cultivars being more stimulating than susceptible ones. Hairy vetch also increased hatch. Roots of cabbage, red clover, alfalfa, and hairy vetch were readily penetrated by juveniles of H. glycines. Maturation to adult occurred only on soybean and hairy vetch. PMID:19283087

  11. SEX-STEROID AND THYROID HORMONE CONCENTRATIONS IN JUVENILE ALLIGATORS (ALLIGATOR MISSISSIPPIENSIS) FROM CONTAMINATED AND REFERENCE LAKES IN FLORIDA, USA

    EPA Science Inventory

    Sex-steroid and thyroid hormones are critical regulators of growth and reproduction in all vertebrates, and several recent studies suggest that environmental chemicals can alter circulating concentrations of these hormones. This study examines plasma concentrations of estradiol-...

  12. SEX-STEROID AND THYROID HORMONE CONCENTRATIONS IN JUVENILE ALLIGATORS (ALLIGATOR MISSISSIPPIENSIS) FROM CONTAMINATED AND REFERENCE LAKES IN FLORIDA, USA

    EPA Science Inventory

    Sex-steroid and thyroid hormones are critical regulators of growth and reproduction in all vertebrates, and several recent studies suggest that environmental chemicals can alter circulating concentrations of these hormones. This study examines plasma concentrations of estradiol-...

  13. Effects of the NMDA receptor antagonist MK-801 on female reproduction and juvenile hormone biosynthesis in the cricket Gryllus bimaculatus and the butterfly Bicyclus anynana.

    PubMed

    Geister, Thorin L; Lorenz, Matthias W; Hoffmann, Klaus H; Fischer, Klaus

    2008-05-01

    Apart from regulating insect development, juvenile hormones (JHs) play an important role in insect reproduction, where they initiate vitellogenin synthesis and regulate the uptake of yolk by the ovary. JH synthesis is a tightly regulated process controlled by neurons and peptidergic neurosecretory cells. One of the known stimulatory regulators of JH biosynthesis is glutamate, and its N-methyl-d-aspartate (NMDA) receptor has been recently found in the cockroach Diploptera punctata. In this study we demonstrate a strong reduction in reproductive output in the tropical butterfly Bicyclus anynana and the Mediterranean field cricket Gryllus bimaculatus caused by the NMDA receptor antagonist MK-801. Such inhibiting effects on reproduction could be overruled by the application of JH mimics. In G. bimaculatus, MK-801 inhibits in vitro JH biosynthesis in the corpora allata and reduces in vivo JH haemolymph titres in a dose-dependent manner. These results suggest that JH biosynthesis in the corpora allata is at least in part controlled by an NMDA receptor with Ca2+ as a second level messenger. Based on our findings we consider NMDA receptor antagonists as important tools for manipulating juvenile hormone biosynthesis and therefore for gaining a better understanding of the mechanistic basis of reproduction.

  14. Molecular cloning and developmental expression of the gene encoding juvenile hormone esterase in the yellow-spotted longicorn beetle, Psacothea hilaris.

    PubMed

    Munyiri, Florence N; Ishikawa, Yukio

    2007-05-01

    Juvenile hormone (JH) plays a key role in the regulation of growth, development, diapause and reproduction in insects. The regulation of JH titers in the insect body is therefore crucial throughout postembryonic development. One of the major pathways of JH metabolism is degradation by a highly selective enzyme, juvenile hormone esterase (JHE). We obtained a full-length cDNA encoding JHE in Psacothea hilaris (PhJHE). The complete PhJHE cDNA sequence is comprised of 1989 bp with an open reading frame of 1785 bp encoding 595 amino acid residues. The deduced protein sequence of PhJHE showed high homology with the Tenebrio molitor JHE (50% amino acid identity) and moderate homology with the Drosophila melanogaster JHE (34%). The PhJHE transcript was expressed mainly in the fat body. PhJHE transcript levels were low until day 3 of the 5th (final) larval instar, then steadily increased reaching a peak on day 13 (the prepupa stage), coinciding well with the peak hemolymph enzyme activity level. Sustained starvation of larvae after a period of feeding stimulated the expression of PhJHE mRNA while feeding the larvae with glucose downregulated its expression. These results are discussed with reference to the induction of precocious metamorphosis in this beetle by starvation.

  15. Bisphenol A influences oestrogen- and thyroid hormone-regulated thyroid hormone receptor expression in rat cerebellar cell culture.

    PubMed

    Somogyi, Virág; Horváth, Tamás L; Tóth, István; Bartha, Tibor; Frenyó, László Vilmos; Kiss, Dávid Sándor; Jócsák, Gergely; Kerti, Annamária; Naftolin, Frederick; Zsarnovszky, Attila

    2016-12-01

    Thyroid hormones (THs) and oestrogens are crucial in the regulation of cerebellar development. TH receptors (TRs) mediate these hormone effects and are regulated by both hormone families. We reported earlier that THs and oestradiol (E2) determine TR levels in cerebellar cell culture. Here we demonstrate the effects of low concentrations (10(-10) M) of the endocrine disruptor (ED) bisphenol A (BPA) on the hormonal (THs, E2) regulation of TRα,β in rat cerebellar cell culture. Primary cerebellar cell cultures, glia-containing and glia-destroyed, were treated with BPA or a combination of BPA and E2 and/or THs. Oestrogen receptor and TH receptor mRNA and protein levels were determined by real-time qPCR and Western blot techniques. The results show that BPA alone decreases, while BPA in combination with THs and/or E2 increases TR mRNA expression. In contrast, BPA alone increased receptor protein expressions, but did not further increase them in combination with THs and/or E2. The modulatory effects of BPA were mediated by the glia; however, the degree of changes also depended on the specific hormone ligand used. The results signify the importance of the regulatory mechanisms interposed between transcription and translation and raise the possibility that BPA could act to influence nuclear hormone receptor levels independently of ligand-receptor interaction.

  16. The influence of competitor density on space use in juvenile striped plateau lizards ( Sceloporus virgatus)

    NASA Astrophysics Data System (ADS)

    Manteuffel, V. Mark; Eiblmaier, Martin

    2008-05-01

    To investigate the role of competitor density in influencing space use patterns of juvenile striped plateau lizards ( Sceloporus virgatus), a density manipulation experiment was conducted within large (800 m 2) field enclosures treated with low (20) and high (60) densities of hatchlings. Enclosures were monitored for 10 months, after which the experiment was replicated. Home range and core area sizes after release of lizards and initial establishment in the fall were significantly reduced in the high-density treatments; fall home range shape, measured as the perimeter-to-area ratio, was significantly reduced in low-density treatments; no significant differences were detected between treatments in core area shape or overlap. During the spring/early summer activity season after the lizard's first winter, no significant differences between density treatments were detected for any of these variables, as enclosure densities had converged between treatments. Individuals in high-density enclosures had increased their space use as competitor density had declined. These results illustrate that competitor density has significant influence on space use by juvenile lizards.

  17. Does structured counselling influence combined hormonal contraceptive choice?

    PubMed Central

    Merckx, Mireille; Donders, Gilbert G; Grandjean, Pascale; Van de Sande, Tine; Weyers, Steven

    2011-01-01

    Objective To assess the effect of structured counselling on women's contraceptive decisions and to evaluate gynaecologists’ perceptions of comprehensive contraceptive counselling. Methods Belgian women (18–40 years old) who were considering using a combined hormonal contraceptive (CHC) were counselled by their gynaecologists about available CHCs (combined oral contraceptive [COC], transdermal patch, vaginal ring), using a comprehensive leaflet. Patients and gynaecologists completed questionnaires that gathered information on the woman's pre- and post-counselling contraceptive choice, her perceptions, and the reasons behind her post-counselling decision. Results The gynaecologists (N = 121) enrolled 1801 eligible women. Nearly all women (94%) were able to choose a method after counselling (53%, 5%, and 27% chose the COC, the patch, and the ring, respectively). Counselling made many women (39%) select a different method: patch use increased from 3% to 5% (p < 0.0001); ring use tripled (from 9% to 27%, p < 0.0001). Women who were undecided before counselling most often opted for the method their gynaecologist recommended, irrespective of counselling. Conclusion Counselling allows most women to select a contraceptive method; a sizeable proportion of them decide on a method different from the one they initially had in mind. Gynaecologists’ preferences influenced the contraceptive choices of women who were initially undecided regarding the method to use. PMID:22066890

  18. Visual pigments and opsin expression in the juveniles of three species of fish (rainbow trout, zebrafish, and killifish) following prolonged exposure to thyroid hormone or retinoic acid.

    PubMed

    Suliman, Tarek; Novales Flamarique, Iñigo

    2014-01-01

    Thyroid hormone (TH) and retinoic acid (RA) are powerful modulators of photoreceptor differentiation during vertebrate retinal development. In the embryos and young juveniles of salmonid fishes and rodents, TH induces switches in opsin expression within individual cones, a phenomenon that also occurs in adult rodents following prolonged (12 week) hypothyroidism. Whether changes in TH levels also modulate opsin expression in the differentiated retina of fish is unknown. Like TH, RA is essential for retinal development, but its role in inducing opsin switches, if any, has not been studied. Here we investigate the action of TH and RA on single-cone opsin expression in juvenile rainbow trout, zebrafish, and killifish and on the absorbance of visual pigments in rainbow trout and zebrafish. Prolonged TH exposure increased the wavelength of maximum absorbance (λmax ) of the rod and the medium (M, green) and long (L, red) wavelength visual pigments in all fish species examined. However, unlike the opsin switch that occurred following TH exposure in the single cones of small juvenile rainbow trout (alevin), opsin expression in large juvenile rainbow trout (smolt), zebrafish, or killifish remained unchanged. RA did not induce any opsin switches or change the visual pigment absorbance of photoreceptors. Neither ligand altered cone photoreceptor densities. We conclude that RA has no effect on opsin expression or visual pigment properties in the differentiated retina of these fishes. In contrast, TH affected both single-cone opsin expression and visual pigment absorbance in the rainbow trout alevin but only visual pigment absorbance in the smolt and in zebrafish. The latter results could be explained by a combination of opsin switches and chromophore shifts from vitamin A1 to vitamin A2. Copyright © 2013 Wiley Periodicals, Inc.

  19. Naturally occurring insect growth regulators. II. Screening of insect and plant extracts as insect juvenile hormone mimics.

    PubMed

    Jacobson, M; Redfern, R E; Mills, G D

    1975-01-01

    Ethereal extracts prepared from the larvae, pupae, or eggs of 10 species of insects and from various parts of 343 species of higher plants were screened for juvenilizing effects against Tenebrio molitor and Oncopeltus fasciatus. Activity in both species was shown by an extract of the larvae of the stable fly, Stomoxys calcitrans, whereas an extract of the pupae was active in O. fasiatus only. Extracts of two plant species (Echinacea angustifolia roots and Chamaecyparis lawsoniana seeds) showed high juvenilizing activity in T. MOLITOR, AND EXtracts of five plant species (Clethra alnifolia stems, leaves, and fruits, Sassafras albidum roots and root bark, Eucalyptus camaldulensis stems and bark, Pinus rigida twigs and leaves, and Iris douglasiana roots, stems, and fruits) were highly active in O. fasciatus an extract of Tsuga canadensis leaves showed lower activity in this insect. Extracts of 16 species of plants showed high insecticidal activity (mortality) in O. fasciatus but lacked juvenilizing properties in both species of test insects.

  20. The Influence of Sex Hormones on Functional Cerebral Asymmetries in Postmenopausal Women

    ERIC Educational Resources Information Center

    Bayer, Ulrike; Erdmann, Gisela

    2008-01-01

    Studies investigating changes in functional cerebral asymmetries (FCAs) with hormonal fluctuations during the menstrual cycle in young women have led to controversial hypotheses about an influence of estrogen (E) and/or progesterone (P) on FCAs. Based on methodical, but also on principal problems in deriving conclusions about hormone effects from…

  1. The Influence of Sex Hormones on Functional Cerebral Asymmetries in Postmenopausal Women

    ERIC Educational Resources Information Center

    Bayer, Ulrike; Erdmann, Gisela

    2008-01-01

    Studies investigating changes in functional cerebral asymmetries (FCAs) with hormonal fluctuations during the menstrual cycle in young women have led to controversial hypotheses about an influence of estrogen (E) and/or progesterone (P) on FCAs. Based on methodical, but also on principal problems in deriving conclusions about hormone effects from…

  2. Occupational Interests and Aptitudes of Juvenile Offenders: Influence of Special Education Experience and Gender

    ERIC Educational Resources Information Center

    Zabel, Robert; Nigro, Frank

    2007-01-01

    Juvenile offenders, particularly those with disabilities, are at high risk for school failure and diminished educational, employment, and social opportunities that contribute to continued social maladjustment as adults. To better understand the occupational preferences and aptitudes of juvenile offenders, 201 juvenile offenders, including 52 who…

  3. COMPARATIVE EMBRYONIC AND LARVAL DEVELOPMENTAL RESPONSES OF THE ESTUARINE GRASS SHRIMP (PALAEMONETES PUGIO) TO THE JUVENILE HORMONE AGONIST FENOXYCARB

    EPA Science Inventory

    This work was undertaken in order to develop a sensitive bioassay which indicates adverse effects of estuarine-applied insecticides on nontarget species. Newly developed 'third generation' insecticides are designed to act as hormone agonists and bind to endogenous insect hormone...

  4. COMPARATIVE EMBRYONIC AND LARVAL DEVELOPMENTAL RESPONSES OF THE ESTUARINE GRASS SHRIMP (PALAEMONETES PUGIO) TO THE JUVENILE HORMONE AGONIST FENOXYCARB

    EPA Science Inventory

    This work was undertaken in order to develop a sensitive bioassay which indicates adverse effects of estuarine-applied insecticides on nontarget species. Newly developed 'third generation' insecticides are designed to act as hormone agonists and bind to endogenous insect hormone...

  5. Influence of sex steroid hormones on the adolescent brain and behavior: An update.

    PubMed

    Vigil, Pilar; Del Río, Juan Pablo; Carrera, BÁrbara; ArÁnguiz, Florencia C; Rioseco, Hernán; Cortés, Manuel E

    2016-08-01

    This review explains the main effects exerted by sex steroids and other hormones on the adolescent brain. During the transition from puberty to adolescence, these hormones participate in the organizational phenomena that structurally shape some brain circuits. In adulthood, this will propitiate some specific behavior as responses to the hormones now activating those neural circuits. Adolescence is, then, a critical "organizational window" for the brain to develop adequately, since steroid hormones perform important functions at this stage. For this reason, the adolescent years are very important for future behaviors in human beings. Changes that occur or fail to occur during adolescence will determine behaviors for the rest of one's lifetime. Consequently, understanding the link between adolescent behavior and brain development as influenced by sex steroids and other hormones and compounds is very important in order to interpret various psycho-affective pathologies. Lay Summary : The effect of steroid hormones on the development of the adolescent brain, and therefore, on adolescent behavior, is noticeable. This review presents their main activational and organizational effects. During the transition from puberty to adolescence, organizational phenomena triggered by steroids structurally affect the remodeling of brain circuits. Later in adulthood, these changes will be reflected in behavioral responses to such hormones. Adolescence can then be seen as a fundamental "organizational window" during which sex steroids and other hormones and compounds play relevant roles. The understanding of the relationship between adolescent behavior and the way hormones influence brain development help understand some psychological disorders.

  6. Influence of sex steroid hormones on the adolescent brain and behavior: An update

    PubMed Central

    Vigil, Pilar; del Río, Juan Pablo; Carrera, BÁrbara; ArÁnguiz, Florencia C.

    2016-01-01

    This review explains the main effects exerted by sex steroids and other hormones on the adolescent brain. During the transition from puberty to adolescence, these hormones participate in the organizational phenomena that structurally shape some brain circuits. In adulthood, this will propitiate some specific behavior as responses to the hormones now activating those neural circuits. Adolescence is, then, a critical “organizational window” for the brain to develop adequately, since steroid hormones perform important functions at this stage. For this reason, the adolescent years are very important for future behaviors in human beings. Changes that occur or fail to occur during adolescence will determine behaviors for the rest of one's lifetime. Consequently, understanding the link between adolescent behavior and brain development as influenced by sex steroids and other hormones and compounds is very important in order to interpret various psycho-affective pathologies. Lay Summary: The effect of steroid hormones on the development of the adolescent brain, and therefore, on adolescent behavior, is noticeable. This review presents their main activational and organizational effects. During the transition from puberty to adolescence, organizational phenomena triggered by steroids structurally affect the remodeling of brain circuits. Later in adulthood, these changes will be reflected in behavioral responses to such hormones. Adolescence can then be seen as a fundamental “organizational window” during which sex steroids and other hormones and compounds play relevant roles. The understanding of the relationship between adolescent behavior and the way hormones influence brain development help understand some psychological disorders. PMID:27833209

  7. VARIATION IN GROWTH, LIPID CLASS AND FATTY ACID COMPOSITION OF THE MUD CRAB, RHITHROPANOPEUS HARRISII (GOULD) DURING LARVAL DEVELOPMENT FOLLOWING EXPOSURE TO AN INSECT JUVENILE HORMONE ANALOG (FENOXYCARB(R))

    EPA Science Inventory

    This study examines the effects of fenoxycarb?, an insect juvenile hormone (JH) analog, on larval growth, and lipid class and fatty acid composition in first crabs of the mud crab Rhithropanopeus harrisii reared through total larval development in nominal water concentrations fr...

  8. VARIATION IN GROWTH, LIPID CLASS AND FATTY ACID COMPOSITION OF THE MUD CRAB, RHITHROPANOPEUS HARRISII (GOULD) DURING LARVAL DEVELOPMENT FOLLOWING EXPOSURE TO AN INSECT JUVENILE HORMONE ANALOG (FENOXYCARB(R))

    EPA Science Inventory

    This study examines the effects of fenoxycarb?, an insect juvenile hormone (JH) analog, on larval growth, and lipid class and fatty acid composition in first crabs of the mud crab Rhithropanopeus harrisii reared through total larval development in nominal water concentrations fr...

  9. Hypermetabolic Conversion of Plant Oil into Water: Endothermic Biochemical Process Stimulated by Juvenile Hormone in the European Firebug, Pyrrhocoris apterus L.

    PubMed Central

    Sláma, Karel; Lukáš, Jan

    2016-01-01

    The physiological and biochemical mechanisms that enable insects to feed on dry food to secure enough water for larval growth were investigated. The study was carried out with a plethora of physiological methods, ranging from the simple volumetric determination of O2 consumption and water intake to more advanced methods such as scanning microrespirography and thermovision imaging of insect’s body temperature. The experiments were done on the European firebug, Pyrrhocoris apterus, which feeds exclusively on dry linden seeds. In order to survive, it needs to drink water or suck a sap from plants occasionally. It was found that the young larval instars compensate the occasional water deficiency by the increased production of metabolic water. The juvenile hormone (JH)-dependent production of metabolic water, which was previously found in other species consuming dry food, was achieved in P. apterus by total metabolic combustion of the dietary lipid (neutral seed oil). The water-producing, hypermetabolic larvae were heated from inside by endothermic energy released from the uncoupling of oxidation from oxidative phosphorylation. The “warm”, hypermetabolic larvae burning the dietary oil into CO2 and water showed the increased rates of respiratory metabolism. Microrespirographic recording of these larvae revealed the ratio of the respiratory quotient (RQ, CO2/O2) of 0.7, which indicated the breakdown of a pure triglyceride. The warm hypermetabolic larvae could be easily spotted and distinguished from the “cold” larvae on the screen of a thermovision camera. The last instar larvae lacking the JH were always only cold. They metabolized a carbohydrate substrate exclusively (RQ = 1.0), while the dietary lipid was stored in the fat body. In comparison with the hypermetabolic larvae of some other species fed on dry food, which exhibited the highest rates of O2 consumption ever recorded in a living organism (10–20 mL O2/g per hour), the metabolic difference between

  10. Variation in adrenal and thyroid hormones with life-history stage in juvenile northern elephant seals (Mirounga angustirostris).

    PubMed

    Jelincic, J A; Tift, M S; Houser, D S; Crocker, D E

    2017-10-01

    The classical approach to quantifying the impact of stressors on wildlife is through characterization of hormones associated with the generalized stress response. However, interpretation of hormone data can be difficult due to the range of natural variation within a species and potential confounds of individual and life-history variables. Blood adrenal and thyroid hormones were measured in 144 chemically immobilized yearling northern elephant seals (Mirounga angustirostris) to characterize variation between sexes and across semiannual haul-outs. There was no relationship between hormone concentrations and time needed for collecting blood nor evidence of diel patterns, suggesting that collection of samples for baseline values can be accomplished without bias due to handling artifacts or time of day. Serum cortisol concentrations did not vary with gender or across haul-out fasts but increased dramatically during molting. Cortisol was correlated with aldosterone across all measured life-history stages. Thyroid hormone levels were lower in females and decreased with fasting in both sexes during the fall haul-out. Cortisol concentrations were inversely associated with total triiodothyronine (T3) and positively associated with reverse T3 concentrations across all measured life-history stages suggesting an important impact of cortisol on deiodinase enzymes and thyroid function. Epinephrine concentrations increased across fasts and norepinephrine concentrations were higher in males than in females. Significant variation in stress hormone concentrations with gender and life-history stage emphasizes the importance of contextual variables when interpreting serum hormone concentrations. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. How hormones influence composition and physiological function of the brain-blood barrier.

    PubMed

    Hampl, R; Bičíková, M; Sosvorová, L

    2015-01-01

    Hormones exert many actions in the brain. Their access and effects in the brain are regulated by the blood-brain barrier (BBB). Hormones as other substances may enter the brain and vice versa either by paracellular way requiring breaching tight junctions stitching the endothelial cells composing the BBB, or by passage through the cells (transcellular way). Hormones influence both ways through their receptors, both membrane and intracellular, present on/in the BBB. In the review the main examples are outlined how hormones influence the expression and function of proteins forming the tight junctions, as well as how they regulate expression and function of major protein transporters mediating transport of various substances including hormone themselves.

  12. Establishment of a short-term, in vivo screening method for detecting chemicals with juvenile hormone activity using adult Daphnia magna.

    PubMed

    Abe, Ryoko; Watanabe, Haruna; Yamamuro, Masumi; Iguchi, Taisen; Tatarazako, Norihisa

    2015-01-01

    Juvenile hormone (JH) and JH agonists have been shown to induce male offspring production in various daphnids, including Daphnia magna using OECD TG211. The critical period (about 1h) for JH action on ova in the parent's ovary to induce male offspring is existing at 7-8h later from ovulation. Therefore, we considered that adult D. magna could be used to produce a short-term screening method for detecting JH analogs. Using this method, we successfully demonstrated male offspring induction in the second broods after exposure to JH or JH agonists. After investigating the exposure time, the number of repetitions and the exposure concentration, we established a short-term, in vivo screening method for detecting JH analogs using adult D. magna. We examined positive and negative control chemicals using a previously developed method and verified the validity of our new testing method.

  13. Molecular cloning, characterization and expression analysis of two juvenile hormone esterase-like carboxylesterase cDNAs in Chinese mitten crab, Eriocheir sinensis.

    PubMed

    Xu, Yu; Zhao, Muzi; Deng, Yanfei; Yang, Yuanjie; Li, Xuguang; Lu, Quanping; Ge, Jiachun; Pan, Jianlin; Xu, Zhiqiang

    2017-03-01

    Precise regulation of methyl farnesoate (MF) titer is of prime importance throughout the crustacean life-cycle. Although the synthetic pathway of MF is well-documented, little is known about its degradation and recycling in crustaceans. Juvenile hormone esterase-like (JHE-like) carboxylesterase (CXE) is a key enzyme in MF degradation, thus playing a significant role in regulating the MF titer. We identified and characterized two cDNAs, Es-CXE1 and Es-CXE2, encoding JHE-like CXEs in Chinese mitten crab. Full-length cDNAs of Es-CXE1 and Es-CXE2 encode proteins composed of 584 and 597 amino acids, respectively, both of which contain a typical carboxylesterase domain. Alignment and phylogenetic analyses revealed that the Es-CXEs are highly similar to those of other crustaceans. To further validate their functions, we evaluated the mRNA expression patterns of the Es-CXEs in various tissues and in different physiological conditions. Tissue-specific expression analysis showed that the two Es-CXEs were predominantly expressed in the hepatopancreas and ovaries, which are the major tissues for MF metabolism. Es-CXE2 expression levels in the hepatopancreas and ovaries were about 100 and 25-fold higher, than the respective Es-CXE1 expressions. During ovarian rapid development stage, the global expressions of Es-CXEs were up-regulated in the hepatopancreas and down-regulated in the ovaries. After eyestalk ablation (ESA), the mRNA expressions of the two Es-CXEs were up-regulated in the hepatopancreas, further indicating their potential in degrading MF. Taken together, our results suggest that Es-CXEs, the key component of the juvenile hormone degradation pathway, may play vital roles in the development and reproduction of the Chinese mitten crab. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. The essence of insect metamorphosis and aging: electrical rewiring of cells driven by the principles of juvenile hormone-dependent Ca(2+)-homeostasis.

    PubMed

    De Loof, Arnold; De Haes, Wouter; Janssen, Tom; Schoofs, Liliane

    2014-04-01

    In holometabolous insects the fall to zero of the titer of Juvenile Hormone ends its still poorly understood "status quo" mode of action in larvae. Concurrently it initiates metamorphosis of which the programmed cell death of all internal tissues that actively secrete proteins, such as the fat body, midgut, salivary glands, prothoracic glands, etc. is the most drastic aspect. These tissues have a very well developed rough endoplasmic reticulum, a known storage site of intracellular Ca(2+). A persistent high [Ca(2+)]i is toxic, lethal and causal to apoptosis. Metamorphosis becomes a logical phenomenon if analyzed from: (1) the causal link between calcium toxicity and apoptosis; (2) the largely overlooked fact that at least some isoforms of Ca(2+)-ATPases have a binding site for farnesol-like endogenous sesquiterpenoids (FRS). The Ca(2+)-ATPase blocker thapsigargin, like JH a sesquiterpenoid derivative, illustrates how absence of JH might work. The Ca(2+)-homeostasis system is concurrently extremely well conserved in evolution and highly variable, enabling tissue-, developmental-, and species specificity. As long as JH succeeds in keeping [Ca(2+)]i low by keeping the Ca(2+)-ATPases pumping, it acts as "the status quo" hormone. When it disappears, its various inhibitory effects are lifted. The electrical wiring system of cells, in particular in the regenerating tissues, is subject to change during metamorphosis. The possibility is discussed that in vertebrates an endogenous farnesol-like sesquiterpenoid, probably farnesol itself, acts as a functional, but hitherto completely overlooked Juvenile anti-aging "Inbrome", a novel concept in signaling. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. Modelling the Influence of Long-Term Hydraulic Conditions on Juvenile Salmon Habitats in AN Upland Scotish River

    NASA Astrophysics Data System (ADS)

    Fabris, L.; Malcolm, I.; Millidine, K. J.; Buddendorf, B.; Tetzlaff, D.; Soulsby, C.

    2015-12-01

    Wild Atlantic salmon populations in Scottish rivers constitute an important economic and recreational resource, as well as being a key component of biodiversity. Salmon have very specific habitat requirements at different life stages and their distribution is therefore strongly influenced by a complex suite of biological and physical controls. Previous research has shown that stream hydrodynamics and channel morphology have a strong influence on the distribution and density of juvenile salmon. Here, we utilise a unique 20 year data set of spatially distributed juvenile salmon densities derived from annual electro-fishing surveys in an upland Scottish river. We examine to what extent the spatial and temporal variability of in-stream hydraulics regulates the spatial and temporal variability in the performance and density of juvenile salmon. A 2-D hydraulic model (River2D) is used to simulate water velocity and water depth under different flow conditions for seven different electro-fishing sites. The selected sites represent different hydromorphological environments including plane-bed, step-pool and pool riffle reaches. The bathymetry of each site was characterised using a total station providing an accurate DTM of the bed, and hydraulic simulations were driven by 20 year stream flow records. Habitat suitability curves, based on direct observations during electro-fishing surveys, were produced for a range of hydraulic indices for juvenile salmon. The hydraulic simulations showed marked spatial differences in juvenile habitat quality both within and between reaches. They also showed marked differences both within and between years. This is most evident in extreme years with wet summers when salmon feeding opportunities may be constrained. Integration of hydraulic habitat models, with fish preference curves and the long term hydrological data allows us to assess whether long-term changes in hydroclimate may be affecting juvenile salmonid populations in the study stream

  16. The Influence of Stress on Juvenile Delinquency: Focusing on the Buffering Effects of Protective Factors among Korean Adolescents.

    PubMed

    Jeon, Hye Sook; Chun, JongSerl

    2017-01-01

    The present study sought to examine self-control, parental support, and peer support as internal and external protective factors that buffer the influence of adolescent stress on delinquency among Korean adolescents. To this end, the paper utilized the 1st-year data from the Korea Youth Panel Study (KYPS) conducted by the National Youth Policy Institute; the study surveyed a total of 3,449 2nd-year middle school students. The results of the hierarchical regression analysis indicated that despite high levels of stress, high self-control mitigated the negative influence of stress on delinquency in adolescents. In contrast, parental and peer support were only found to be directly influential on juvenile delinquency. Parental support had only negative influences on status delinquency, and peer support had positive influences on both status and serious delinquency. Based on these results, we propose implications for preventing and intervening with juvenile delinquency.

  17. Body size and condition influence migration timing of juvenile Arctic grayling

    USGS Publications Warehouse

    Heim, Kurt C.; Wipfli, Mark S.; Whitman, Matthew S.; Seitz, Andrew C

    2016-01-01

    Freshwater fishes utilising seasonally available habitats within annual migratory circuits time movements out of such habitats with changing hydrology, although individual attributes of fish may also mediate the behavioural response to environmental conditions. We tagged juvenile Arctic grayling in a seasonally flowing stream on the Arctic Coastal Plain in Alaska and recorded migration timing towards overwintering habitat. We examined the relationship between individual migration date, and fork length (FL) and body condition index (BCI) for fish tagged in June, July and August in three separate models. Larger fish migrated earlier; however, only the August model suggested a significant relationship with BCI. In this model, 42% of variability in migration timing was explained by FL and BCI, and fish in better condition were predicted to migrate earlier than those in poor condition. Here, the majority (33%) of variability was captured by FL with an additional 9% attributable to BCI. We also noted strong seasonal trends in BCI reflecting overwinter mass loss and subsequent growth within the study area. These results are interpreted in the context of size and energetic state-specific risks of overwinter starvation and mortality (which can be very high in the Arctic), which may influence individuals at greater risk to extend summer foraging in a risky, yet prey rich, habitat. Our research provides further evidence that heterogeneity among individuals within a population can influence migratory behaviour and identifies potential risks to late season migrants in Arctic beaded stream habitats influenced by climate change and petroleum development.

  18. Mitochondrial gene expression: influence of nutrients and hormones.

    PubMed

    Berdanier, Carolyn D

    2006-11-01

    Mitochondrial gene transcription research has exploded over the last decade. Nuclear-encoded proteins, nutrients, and hormones all work to regulate the transcription of this genome. To date, very few of the transcription factors have been shown to have negative effects on mitochondrial gene expression, although there are likely conditions where such downregulation may occur.

  19. Early Hormonal Influences on Cognitive Functioning in Congenital Adrenal Hyperplasia.

    ERIC Educational Resources Information Center

    Resnick, Susan M.; And Others

    1986-01-01

    Reports the results of cognitive test performance and early childhood activities in individuals with congenital adrenal hyperplasia, an autosomal recessive disorder associated with elevated prenatal adrenal androgen levels, demonstrating the effects of early exposure to excess androgenizing hormones on sexually dimorphic cognitive functioning.…

  20. Effects of the juvenile hormone analogue methoprene on rate of behavioural development, foraging performance and navigation in honey bees (Apis mellifera).

    PubMed

    Chang, Lun-Hsien; Barron, Andrew B; Cheng, Ken

    2015-06-01

    Worker honey bees change roles as they age as part of a hormonally regulated process of behavioural development that ends with a specialised foraging phase. The rate of behavioural development is highly plastic and responsive to changes in colony condition such that forager losses, disease or nutritional stresses accelerate behavioural development and cause an early onset of foraging in workers. It is not clear to what degree the behavioural development of workers can be accelerated without there being a cost in terms of reduced foraging performance. Here, we compared the foraging performance of bees induced to accelerate their behavioural development by treatment with the juvenile hormone analogue methoprene with that of controls that developed at a normal rate. Methoprene treatment accelerated the onset of both flight and foraging behaviour in workers, but it also reduced foraging span, the total time spent foraging and the number of completed foraging trips. Methoprene treatment did not alter performance in a short-range navigation task, however. These data indicate a limitation to the physiological plasticity of bees, and a trade off between forager performance and the speed at which bees begin foraging. Chronic stressors will be expected to reduce the mean age of the foraging force, and therefore also reduce the efficiency of the foraging force. This interaction may explain why honey bee colonies react to sustained stressors with non-linear population decline. © 2015. Published by The Company of Biologists Ltd.

  1. Absence of juvenile hormone signalling regulates the dynamic expression profiles of nutritional metabolism genes during diapause preparation in the cabbage beetle Colaphellus bowringi.

    PubMed

    Liu, W; Tan, Q-Q; Zhu, L; Li, Y; Zhu, F; Lei, C-L; Wang, X-P

    2017-10-01

    Temperate insects have evolved diapause, a period of programmed developmental arrest during specific life stages, to survive unfavourable conditions. During the diapause preparation phase (DPP), diapause-destined individuals generally store large amounts of fat by regulating nutrition distribution for the energy requirement during diapause maintenance and postdiapause development. Although nutritional patterns during the DPP have been investigated at physiological and biochemical levels in many insects, it remains largely unknown how nutritional metabolism is regulated during the DPP at molecular levels. We used RNA sequencing to compare gene expression profiles of adult female cabbage beetles Colaphellus bowringi during the preoviposition phase (POP) and the DPP. Most differentially expressed genes were involved in specific metabolic pathways during the DPP. Genes related to lipid and carbohydrate metabolic pathways were clearly highly expressed during the DPP, whereas genes related to protein metabolic pathways were highly expressed during the POP. Hormone challenge and RNA interference experiments revealed that juvenile hormone via its nuclear receptor methoprene-tolerant mediated the expression of genes associated with nutritional metabolism during the DPP. This work not only sheds light on the mechanisms of diapause preparation, but also provides new insights into the molecular basis of environmental plasticity in insects. © 2017 The Royal Entomological Society.

  2. Juvenile hormone counteracts the bHLH-PAS transcription factors MET and GCE to prevent caspase-dependent programmed cell death in Drosophila.

    PubMed

    Liu, Ying; Sheng, Zhentao; Liu, Hanhan; Wen, Di; He, Qianyu; Wang, Sheng; Shao, Wei; Jiang, Rong-Jing; An, Shiheng; Sun, Yaning; Bendena, William G; Wang, Jian; Gilbert, Lawrence I; Wilson, Thomas G; Song, Qisheng; Li, Sheng

    2009-06-01

    Juvenile hormone (JH) regulates many developmental and physiological events in insects, but its molecular mechanism remains conjectural. Here we report that genetic ablation of the corpus allatum cells of the Drosophila ring gland (the JH source) resulted in JH deficiency, pupal lethality and precocious and enhanced programmed cell death (PCD) of the larval fat body. In the fat body of the JH-deficient animals, Dronc and Drice, two caspase genes that are crucial for PCD induced by the molting hormone 20-hydroxyecdysone (20E), were significantly upregulated. These results demonstrated that JH antagonizes 20E-induced PCD by restricting the mRNA levels of Dronc and Drice. The antagonizing effect of JH on 20E-induced PCD in the fat body was further confirmed in the JH-deficient animals by 20E treatment and RNA interference of the 20E receptor EcR. Moreover, MET and GCE, the bHLH-PAS transcription factors involved in JH action, were shown to induce PCD by upregulating Dronc and Drice. In the Met- and gce-deficient animals, Dronc and Drice were downregulated, whereas in the Met-overexpression fat body, Dronc and Drice were significantly upregulated leading to precocious and enhanced PCD, and this upregulation could be suppressed by application of the JH agonist methoprene. For the first time, we demonstrate that JH counteracts MET and GCE to prevent caspase-dependent PCD in controlling fat body remodeling and larval-pupal metamorphosis in Drosophila.

  3. Effects of hypophysectomy and substitution with growth hormone, prolactin, and thyroxine on growth and deposition in juvenile frogs, Xenopus laevis.

    PubMed

    Nybroe, O; Rosenkilde, P; Ryttersgaard, L

    1985-02-01

    Growth was studied in young metamorphosed frogs, Xenopus laevis, following hypophysectomy and substitution with mammalian growth hormone (bGH or pGH), mammalian prolactin (oPRL), and thyroxine. Hypophysectomy reduced growth (weight and length increase). GH and PRL proved equally efficient in restoring growth and in mobilizing energy stores (fat bodies and liver glycogen). No synergistic effects between GH and PRL could be observed. GH exerted its growth-promoting effects by increasing gross food conversion efficiency (weight increase/food intake), but did not stimulate appetite. Moderate GH doses given to a group of frogs in growth stagnation exerted moderate metabolic effects, and may have stimulated appetite in some animals, but did not increase body size significantly. Thyroxine was unable to promote growth, but increased mobilization of energy stores. Hypophysectomy and hormone substitution affected feeding behavior. The nature of the actions of pituitary somatotropic hormones and of thyroxine on growth and deposition is discussed.

  4. Sex bias in the outcome of human tropical infectious diseases: influence of steroid hormones.

    PubMed

    Bernin, Hannah; Lotter, Hanna

    2014-07-15

    Numerous investigations have revealed a bias toward males in the susceptibility to and severity of a variety of infectious diseases, especially parasitic diseases. Although different external factors may influence the exposure to infection sources among males and females, one recurrent phenomenon indicative of a hormonal influence is the simultaneous increase in disease occurrence and hormonal activity during the aging process. Substantial evidence to support the influence of hormones on disease requires rigorously controlled human population studies, as well as the same sex dimorphism being observed under controlled laboratory conditions. To date, only very few studies conducted have fulfilled these criteria. Herein, we introduce tropical infectious diseases, including amebiasis, malaria, leishmaniasis, toxoplasmosis, schistosomiasis, and paracoccidioidomycosis, in which hormones are suspected to play a role in disease processes. We summarize the most recent findings from epidemiologic studies in humans and from hormone replacement studies in animal models, as well as data regarding the influence of hormones on immune responses underlying the pathology of the diseases. © The Author 2013. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  5. Social and behavioural influences on the uptake of hormone replacement therapy among younger women.

    PubMed

    Kuh, D; Hardy, R; Wadsworth, M

    2000-06-01

    To describe the social and behavioural influences on the uptake of hormone replacement therapy before the age of 50. Nationally representative birth cohort study with detailed hormone replacement therapy histories and prospective data on health, social and behavioural factors collected throughout life. England, Scotland and Wales. General population sample of 1,572 women followed to the age of 50 years. Age at first hormone replacement therapy use By the age of 50 years, 45% of women had tried hormone replacement therapy and one third were current users. Over two-fifths of users had tried more than one preparation and over one quarter had episodic use. For the vast majority, prescribing conformed to current guidelines. More educated women took hormone replacement therapy for long term prevention compared with their less educated peers. Hysterectomy increased the chances of taking hormone replacement therapy, particularly where an oophorectomy had also been performed, and was associated with longer and more continuous use. Results of a Cox's proportional hazards model showed that the age at which first hormone replacement therapy is used by women who have not had a hysterectomy was influenced by previous contact with health services for menstrual disorders, previous use of oral contraception and cigarettes, past reporting of health problems and low social class. The relation between smoking and low social class with early use of hormone replacement therapy may be due to their association with early menopause. The trend over the last two decades towards greater use of hormone replacement therapy has continued unabated for younger women. So far, hormone replacement therapy users in this generation have had less healthy lifestyles and social advantages than nonusers, in contrast to many older mainly American studies based on earlier generations. This may have long term implications for health and health care as the postwar baby boom generation ages.

  6. Sleep patterns in male juvenile monkeys influenced by gestational iron deprivation and MAOA genotype

    PubMed Central

    Golub, Mari S.; Hogrefe, Casey E.

    2014-01-01

    Individual differences in sleep patterns of children may have developmental origins. Here, two factors known to influence behavioral development, monoamine oxidase A (MAOA) genotype and prenatal iron deficiency, were examined for their influences on sleep in juvenile rhesus monkeys. Sleep was assessed based on a threshold for inactivity as recorded by activity monitors. Pregnant monkeys were fed diets containing either 100 ppm Fe (iron sufficient) or 10 ppm Fe (iron deficient). At 3-4 months of age, male offspring were genotyped for polymorphisms of the MAOA gene that lead to high or low transcription. At one and two years of age, sleep was assessed. Several parameters of sleep architecture changed with age. At one year of age, monkeys with low-MAOA genotype demonstrated a trend toward more sleep at night than the high-MAOA group. When monkeys reached two years of age, prenatal iron deficiency reversed this trend; iron deficiency in the low-MAOA group resulted in sleep fragmentation, more awakenings at night and more sleep episodes during the day, as compared to prenatal iron sufficiency in that genotype. The ability to consolidate sleep during the dark cycle was disrupted by prenatal iron deficiency specifically in monkeys with the low-MAOA genotype. PMID:25351859

  7. Influence of diabetes surgery on gut hormones and incretins.

    PubMed

    Papamargaritis, D; Miras, A D; le Roux, Carel W

    2013-03-01

    The dramatic rise in the prevalence of obesity and type 2 diabetes mellitus (T2DM) has become a major global public health issue. There is increasing evidence that metabolic surgery is more effective than diet and exercise for diabetes remission and weight loss. Moreover, the rapid time course and disproportional degree of T2DM improvement after metabolic procedures compared with equivalent weight loss with conservative treatment, suggest surgery-specific, weight-independent effects on glucose homeostasis. Gut hormones has been proposed as one of the potential mechanisms for the weight-independent diabetes remission and long-term weight loss after these procedures. In this review we discuss the available current metabolic procedures and we review the current human data on changes in gut hormones after each metabolic procedure.

  8. Growth hormone actions during development influence adult phenotype and longevity.

    PubMed

    Bartke, A; Sun, L; Fang, Y; Hill, C

    2016-12-15

    There is considerable evidence that exposure to undernutrition, overnutrition, stress or endocrine disruptors during fetal development can increase the probability of obesity, hypertension, cardiovascular disease and other problems in adult life. In contrast to these findings, reducing early postnatal growth by altering maternal diet or number of pups in a litter can increase longevity. In hypopituitary Ames dwarf mice, which are remarkably long lived, a brief period of growth hormone therapy starting at 1 or 2weeks of age reduces longevity and normalizes ("rescues") multiple aging-related traits. Collectively, these findings indicate that nutritional and hormonal signals during development can have profound impact on the trajectory of aging. We suspect that altered "programming" of aging during development may represent one of the mechanisms of the Developmental Origins of Health and Disease (DOHaD) and the detrimental effects of "catch-up" growth. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Thyroid hormone influences muscle mechanics in carp (Cyprinus carpio) independently from SERCA activity.

    PubMed

    James, Rob S; Little, Alexander G; Tallis, Jason; Seebacher, Frank

    2016-09-15

    Thyroid hormone is a key regulator of metabolism, and in zebrafish, hypothyroidism decreases sustained and burst swimming performance. These effects are accompanied by decreases in both metabolic scope and the activity of sarco-endoplasmic reticulum ATPase (SERCA) in zebrafish. Our aim was to determine whether thyroid hormone affects skeletal muscle contractile function directly and whether these effects are mediated by influencing SERCA activity. We show that hypothyroidism reduces sustained locomotor performance but not sprint performance in carp (Cyprinus carpio). We accept our hypothesis that hypothyroidism reduces force production in isolated skeletal muscle, when compared with the thyroid hormone T2, but we reject the hypothesis that this effect is mediated by influencing SERCA activity. Blocking SERCA activity with thapsigargin reduced muscle fatigue resistance, but hypothyroidism had no effect on fatigue. Hence, thyroid hormone plays a role in determining isolated skeletal muscle mechanics, but its effects are more likely to be mediated by mechanisms other than affecting SERCA activity.

  10. Dietary contaminant exposure affects plasma testosterone, but not thyroid hormones, vitamin A, and vitamin E, in male juvenile arctic foxes (Vulpes lagopus).

    PubMed

    Hallanger, Ingeborg G; Jørgensen, Even H; Fuglei, Eva; Ahlstrøm, Øystein; Muir, Derek C G; Jenssen, Bjørn Munro

    2012-01-01

    Levels of persistent organic pollutants (POP), such as polychlorinated biphenyls (PCB), are high in many Arctic top predators, including the Arctic fox (Vulpes lagopus). The aim of this study was to examine possible endocrine-disruptive effects of dietary POP exposure in male juvenile Arctic foxes in a controlled exposure experiment. The study was conducted using domesticated farmed blue foxes (Vulpes lagopus) as a model species. Two groups of newly weaned male foxes received a diet supplemented with either minke whale (Baleneoptera acutorostrata) blubber that was naturally contaminated with POP (exposed group, n = 5 or 21), or pork (Sus scrofa) fat (control group, n = 5 or 21). When the foxes were 6 mo old and had received the 2 diets for approximately 4 mo (147 d), effects of the dietary exposure to POP on plasma concentrations of testosterone (T), thyroid hormones (TH), thyroid-stimulating hormone (TSH), retinol (vitamin A), and tocopherol (viramin E) were examined. At sampling, the total body concentrations of 104 PCB congeners were 0.1 ± 0.03 μg/g lipid weight (l.w.; n = 5 [mean ± standard deviation]) and 1.5 ± 0.17 μg/g l.w. (n = 5) in the control and exposed groups, respectively. Plasma testosterone concentrations in the exposed male foxes were significantly lower than in the control males, being approximately 25% of that in the exposed foxes. There were no between-treatment differences for TH, TSH, retinol, or tocopherol. The results suggest that the high POP levels experienced by costal populations of Arctic foxes, such as in Svalbard and Iceland, may result in delayed masculine maturation during adolescence. Sex hormone disruption during puberty may thus have lifetime consequences on all aspects of reproductive function in adult male foxes.

  11. Influence of glucocorticoids and growth hormone on insulin sensitivity in humans.

    PubMed

    Yuen, K C J; Chong, L E; Riddle, M C

    2013-06-01

    The seminal concept proposed by Sir Harold Himsworth more than 75 years ago that a large number of patients with diabetes were 'insulin insensitive', now termed insulin resistance, has now expanded to include several endocrine syndromes, namely those of glucocorticoid excess, and growth hormone excess and deficiency. Synthetic glucocorticoids are increasingly used to treat a wide variety of chronic diseases, whereas the beneficial effects of recombinant growth hormone replacement therapy in children and adults with growth hormone deficiency have now been well-recognized for over 25 years. However, clinical and experimental studies have established that increased circulating levels of glucocorticoids and growth hormone can also lead to worsening of insulin resistance, glucose intolerance, overt diabetes mellitus and cardiovascular disease. Improved understanding of the physiological 24-h rhythmicity of glucocorticoid and growth hormone secretion and its influence on the dawn phenomenon and the Staub-Trauggot effect has therefore led to renewed interest in studies on the mechanisms of insulin resistance induced by exogenous administration of glucocorticoids and growth hormone in humans. In this review, we describe the physiological events that result from the presence of resistance to insulin action at the level of skeletal muscle, adipose tissue, and liver, describe the known mechanisms of glucocorticoid- and growth hormone-mediated insulin resistance, and provide an update of the contributions of glucocorticoids and growth hormone to understanding the pathophysiology of insulin resistance and its effects on several endocrine syndromes. © 2013 The Authors. Diabetic Medicine © 2013 Diabetes UK.

  12. Juvenile angiofibroma

    MedlinePlus

    Nasal tumor; Angiofibroma - juvenile; Benign nasal tumor; Juvenile nasal angiofibroma; JNA ... Juvenile angiofibroma is not very common. It is most often found in adolescent boys. The tumor contains ...

  13. Effect of a peri-juvenile exposure to Triclosan on serum androgens and thyroid hormone in the male Wistar rat

    EPA Science Inventory

    Triclosan (5-chloro-2-(2,4-dichlorophenoxy)phenol) is a potent antibacterial and antifungal compound that is widely used in personal care products. Studies testing triclosan exposure in the bullfrog showed altered thyroid hormone homeostasis. More recently, triclosan has been s...

  14. Effect of a peri-juvenile exposure to Triclosan on serum androgens and thyroid hormone in the male Wistar rat

    EPA Science Inventory

    Triclosan (5-chloro-2-(2,4-dichlorophenoxy)phenol) is a potent antibacterial and antifungal compound that is widely used in personal care products. Studies testing triclosan exposure in the bullfrog showed altered thyroid hormone homeostasis. More recently, triclosan has been s...

  15. Weather, hydroregime, and breeding effort influence juvenile recruitment of anurans: implications for climate change

    DOE PAGES

    Greenberg, C. H.; Zarnoch, S. J.; Austin, J. D.

    2017-05-03

    Amphibians that primarily breed in ephemeral wetlands are especially vulnerable to climate change because they rely on rainfall or temperature to initiate breeding and create suitable hydroregimes (water duration, timing, frequency, depth) for reproductive success. Hydroregime effects on reproductive success are likely to differ among species because of differences in reproductive strategies: the length and timing of breeding period, rate of larval development, and timing of metamorphosis. We applied an information-theoretic approach to 22 consecutive years of continuous amphibian trapping data at eight ephemeral wetlands to test hypotheses regarding environmental (hydroregime, weather) and biological (adult breeding effort) factors affecting juvenilemore » recruitment (JR) by six focal species representing four reproductive strategies. We hypothesized that (1) JR by species with similar reproductive strategies would be influenced by similar variables; (2) JR would be higher for all species when models encompassed the maximum time span of potential tadpole occurrence and development; and (3) JR rates within individual wetlands and breeding cycles would correlate most closely between species with similar breeding strategies. The best model for all focal species (except Scaphiopus holbrookii) encompassed the maximum time span and indicated that ≥1 hydroregime variable, total precipitation, or both were important drivers of reproductive success; average air temperature was not. Continuous hydroperiod through peak juvenile emigration was an important predictor of JR for species with prolonged breeding periods, slow larval development, and a “fixed” late spring start date for juvenile emigration (regardless of when oviposition occurred, or cohort age; Lithobates capito, Lithobates sphenocephalus), but not for species with rapid larval development and continual emigration as cohorts complete metamorphosis (Anaxyrus terrestris, Anaxyrus quercicus, Gastrophryne

  16. Influences of sex, incubation temperature, and environmental quality on gonadal estrogen and androgen receptor messenger RNA expression in juvenile American alligators (Alligator mississippiensis).

    PubMed

    Moore, Brandon C; Milnes, Matthew R; Kohno, Satomi; Katsu, Yoshinao; Iguchi, Taisen; Guillette, Louis J

    2010-01-01

    Gonadal steroid hormone receptors play a vital role in transforming ligand signals into gene expression. We have shown previously that gonads from wild-caught juvenile alligators express greater levels of estrogen receptor 1 (ESR1) than estrogen receptor 2 (ESR2). Furthermore, sexually dimorphic ESR2 mRNA expression (female > male) observed in animals from the reference site (Lake Woodruff, FL, USA) was lost in alligators from the contaminated Lake Apopka (FL, USA). We postulated that environmental contaminant exposure could influence gonadal steroid hormone receptor expression. Here, we address questions regarding gonadal estrogen and androgen receptor (AR) mRNA expression in 1-yr-old, laboratory-raised alligators. What are relative expression levels within gonads? Do these levels vary between sexes or incubation temperatures? Can contaminant exposure change these levels? We observed a similar pattern of expression (ESR1 > AR > ESR2) in ovary and testis. However, both incubation temperature and environment modulated expression. Males incubated at 33.5 degrees C expressed greater AR levels than females incubated at 30 degrees C; dimorphic expression was not observed in animals incubated at 32 degrees C. Compared to Lake Woodruff alligators, Lake Apopka animals of both sexes showed lesser ESR2 mRNA expression levels. Employing cluster analyses, we integrated these receptor expression patterns with those of steroidogenic factors. Elevated ESR2 and CYP19A1 expressions were diagnostic of alligator ovary, whereas elevated HSD3B1, CYP11A1, and CYP17A1 expressions were indicative of testis. In contrast, AR, ESR1, and NR5A1 showed variable expressions that were not entirely associated with sex. These findings demonstrate that the mRNA expression of receptors required for steroid hormone signaling are modified by exposure to environmental factors, including temperature and contaminants.

  17. Influences of Sex, Incubation Temperature, and Environmental Quality on Gonadal Estrogen and Androgen Receptor Messenger RNA Expression in Juvenile American Alligators (Alligator mississippiensis)1

    PubMed Central

    Moore, Brandon C.; Milnes, Matthew R.; Kohno, Satomi; Katsu, Yoshinao; Iguchi, Taisen; Guillette, Louis J.

    2009-01-01

    Gonadal steroid hormone receptors play a vital role in transforming ligand signals into gene expression. We have shown previously that gonads from wild-caught juvenile alligators express greater levels of estrogen receptor 1 (ESR1) than estrogen receptor 2 (ESR2). Furthermore, sexually dimorphic ESR2 mRNA expression (female > male) observed in animals from the reference site (Lake Woodruff, FL, USA) was lost in alligators from the contaminated Lake Apopka (FL, USA). We postulated that environmental contaminant exposure could influence gonadal steroid hormone receptor expression. Here, we address questions regarding gonadal estrogen and androgen receptor (AR) mRNA expression in 1-yr-old, laboratory-raised alligators. What are relative expression levels within gonads? Do these levels vary between sexes or incubation temperatures? Can contaminant exposure change these levels? We observed a similar pattern of expression (ESR1 > AR > ESR2) in ovary and testis. However, both incubation temperature and environment modulated expression. Males incubated at 33.5°C expressed greater AR levels than females incubated at 30°C; dimorphic expression was not observed in animals incubated at 32°C. Compared to Lake Woodruff alligators, Lake Apopka animals of both sexes showed lesser ESR2 mRNA expression levels. Employing cluster analyses, we integrated these receptor expression patterns with those of steroidogenic factors. Elevated ESR2 and CYP19A1 expressions were diagnostic of alligator ovary, whereas elevated HSD3B1, CYP11A1, and CYP17A1 expressions were indicative of testis. In contrast, AR, ESR1, and NR5A1 showed variable expressions that were not entirely associated with sex. These findings demonstrate that the mRNA expression of receptors required for steroid hormone signaling are modified by exposure to environmental factors, including temperature and contaminants. PMID:19759368

  18. The hormone-dependent function of Hsp90 in the crosstalk between 20-hydroxyecdysone and juvenile hormone signaling pathways in insects is determined by differential phosphorylation and protein interactions.

    PubMed

    Liu, Wen; Zhang, Feng-Xia; Cai, Mei-Juan; Zhao, Wen-Li; Li, Xiang-Ru; Wang, Jin-Xing; Zhao, Xiao-Fan

    2013-11-01

    Heat shock protein 90 (Hsp90) interacts with steroid hormone receptors, signaling kinases, and various transcription factors. However, the mechanism by which Hsp90 interacts with different proteins in various pathways remains unclear. Western blot was used to study Hsp90 expression profile in Helicoverpa armigera (Lepidoptera). RNA interference was performed to investigate the function of Hsp90 in 20-hydroxyecdysone (20E) and juvenile hormone (JH) signal pathways. The binding of Hsp90 to the transcription factor ultraspiracle protein (USP1) and JH candidate receptor methoprene-tolerant (Met1) was analyzed by co-immunoprecipitation. Phospho-(Ser) PKC substrate antibody was used to detect Hsp90 phosphorylation. Hsp90 participated in 20E- or JH-induced gene expression. 20E induced the interaction between Hsp90 and USP1, whereas JH III and methoprene induced the interaction between Hsp90 and Met1, respectively. 20E and JH counteracted each other for these protein interactions. Both JH III and methoprene induced protein kinase C (PKC) phosphorylation of Hsp90. This process could be inhibited by phospholipase C (PLC) and PKC inhibitors. 20E suppressed JH III- or methoprene-induced PKC phosphorylation of Hsp90. 20E maintained the non-PKC-phosphorylation status of Hsp90. Hsp90 interacted with USP1 to induce gene expression in the 20E pathway. JH regulated the PKC-phosphorylation status of Hsp90. Hsp90 also interacted with Met1 to induce gene expression in the JH pathway. Our study describes a novel mechanism of Hsp90 action by altering phosphorylation and protein interaction in various hormonal signaling pathways. © 2013.

  19. Differential impacts of juvenile hormone, soldier head extract and alternate caste phenotypes on host and symbiont transcriptome composition in the gut of the termite Reticulitermes flavipes.

    PubMed

    Sen, Ruchira; Raychoudhury, Rhitoban; Cai, Yunpeng; Sun, Yijun; Lietze, Verena-Ulrike; Boucias, Drion G; Scharf, Michael E

    2013-07-19

    Termites are highly eusocial insects and show a division of labor whereby morphologically distinct individuals specialize in distinct tasks. In the lower termite Reticulitermes flavipes (Rhinotermitidae), non-reproducing individuals form the worker and soldier castes, which specialize in helping (e.g., brood care, cleaning, foraging) and defense behaviors, respectively. Workers are totipotent juveniles that can either undergo status quo molts or develop into soldiers or neotenic reproductives. This caste differentiation can be regulated by juvenile hormone (JH) and primer pheromones contained in soldier head extracts (SHE). Here we offered worker termites a cellulose diet treated with JH or SHE for 24-hr, or held them with live soldiers (LS) or live neotenic reproductives (LR). We then determined gene expression profiles of the host termite gut and protozoan symbionts concurrently using custom cDNA oligo-microarrays containing 10,990 individual ESTs. JH was the most influential treatment (501 total ESTs affected), followed by LS (24 ESTs), LR (12 ESTs) and SHE treatments (6 ESTs). The majority of JH up- and downregulated ESTs were of host and symbiont origin, respectively; in contrast, SHE, LR and LS treatments had more uniform impacts on host and symbiont gene expression. Repeat "follow-up" bioassays investigating combined JH + SHE impacts in relation to individual JH and SHE treatments on a subset of array-positive genes revealed (i) JH and SHE treatments had opposite impacts on gene expression and (ii) JH + SHE impacts on gene expression were generally intermediate between JH and SHE. Our results show that JH impacts hundreds of termite and symbiont genes within 24-hr, strongly suggesting a role for the termite gut in JH-dependent caste determination. Additionally, differential impacts of SHE and LS treatments were observed that are in strong agreement with previous studies that specifically investigated soldier caste regulation. However, it is likely

  20. Influence of past breast feeding on pattern and severity of presentation of juvenile idiopathic arthritis.

    PubMed

    Hyrich, Kimme L; Baildam, Eileen; Pickford, Hannah; Chieng, Alice; Davidson, Joyce E; Foster, Helen; Gardner-Medwin, Janet; Wedderburn, Lucy R; Thomson, Wendy

    2016-04-01

    This analysis aimed to study the influence of breast feeding on the pattern and severity of juvenile idiopathic arthritis (JIA) at presentation. The association between ever versus never breast feeding and disease severity at onset was compared in 923 children with JIA recruited to the UK Childhood Arthritis Prospective Study at first presentation to rheumatology. Fifty six per cent of children were ever breast fed (median 3.7 months). Breastfed children reported a lower median age at onset, a lower Childhood Health Assessment Questionnaire (CHAQ), a measure of disease severity, lower parent general evaluation scores and lower pain at presentation. There was a trend towards a higher proportion of breastfed children with rheumatoid factor-negative polyarthritis, but lesser enthesitis-related and psoriatic arthritis. There was a statistically significant inverse association between breast feeding and high CHAQ, even after adjusting for differences in socioeconomic status (adjusted OR 0.61 (95% CI 0.39 to 0.95)). Further work to understand the reasons behind these associations is required. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  1. Influence of Photoperiod on Hormones, Behavior, and Immune Function

    PubMed Central

    Walton, James C.; Weil, Zachary M.; Nelson, Randy J.

    2011-01-01

    Photoperiodism is the ability of plants and animals to measure environmental day length to ascertain time of year. Central to the evolution of photoperiodism in animals is the adaptive distribution of energetically challenging activities across the year to optimize reproductive fitness while balancing the energetic tradeoffs necessary for seasonally- appropriate survival strategies. The ability to accurately predict future events requires endogenous mechanisms to permit physiological anticipation of annual conditions. Day length provides a virtually noise free environmental signal to monitor and accurately predict time of the year. In mammals, melatonin provides the hormonal signal transducing day length. Duration of pineal melatonin is inversely related to day length and its secretion drives enduring changes in many physiological systems, including the HPA, HPG, and brain-gut axes, the autonomic nervous system, and the immune system. Thus, melatonin is the fulcrum mediating redistribution of energetic investment among physiological processes to maximize fitness and survival. PMID:21156187

  2. Influence of parathyroid hormone on bone cell ultrastructure

    SciTech Connect

    Matthews, J.L.; Talmage, R.V.

    1981-05-01

    A study in rats demonstrated that morphologic changes in the bone osteocytes and osteoblasts are produced following parathyroid hormone (PTH) injection into thyroparathyroidectomized animals. It further showed that similar changes occur in normal rats as the result of extended fasting. The most significant morphologic alterations involved surface microvilli and blebs as determined by scanning electron microscopy. Transmission electron microscopy studies showed alterations in the cisternae of the rough endoplasmic reticulum. Additionally, cell shape varied markedly from the control cuboidal morphology. These morphologic changes occurred during peak periods of plasma calcium change and returned to control morphology as plasma calcium levels normalized. The study supports the concept that osteocytes and lining cells on the surface of bone play a role in maintenance of plasma calcium concentrations. (JMT)

  3. Influence of photoperiod on hormones, behavior, and immune function.

    PubMed

    Walton, James C; Weil, Zachary M; Nelson, Randy J

    2011-08-01

    Photoperiodism is the ability of plants and animals to measure environmental day length to ascertain time of year. Central to the evolution of photoperiodism in animals is the adaptive distribution of energetically challenging activities across the year to optimize reproductive fitness while balancing the energetic tradeoffs necessary for seasonally-appropriate survival strategies. The ability to accurately predict future events requires endogenous mechanisms to permit physiological anticipation of annual conditions. Day length provides a virtually noise free environmental signal to monitor and accurately predict time of the year. In mammals, melatonin provides the hormonal signal transducing day length. Duration of pineal melatonin is inversely related to day length and its secretion drives enduring changes in many physiological systems, including the HPA, HPG, and brain-gut axes, the autonomic nervous system, and the immune system. Thus, melatonin is the fulcrum mediating redistribution of energetic investment among physiological processes to maximize fitness and survival. Copyright © 2010 Elsevier Inc. All rights reserved.

  4. HORMONAL INFLUENCES ON MAMMARY TUMORS OF THE RAT

    PubMed Central

    Huggins, Charles; Torralba, Yolanda; Mainzer, Klaus

    1956-01-01

    A transplanted mammary fibroadenoma was found to grow in 95 per cent of intact adult female rats and the increment of tumor weights was progressive and logarithmic. The growth of the tumor was retarded by ovariectomy and still more when this was combined with adrenalectomy. In ovariectomized rats the growth of the tumor was stimulated by phenolic estrogens, this increase being enhanced when progesterone was added. In these responses to hormonal changes the mammary gland and the tumor resembled each other. Yet there are many differences between the growth of the fibroadenoma and that of the mammary gland. In contrast to the progressive growth which occurred in intact adult females there was a prolonged period of indolent growth of transplants in hypophysectomized rats; but after many weeks active growth began and the tumors eventually reached large size. During the period of quiescent growth the tumor was cytologically atrophic but after the growth spurt had started the microscopic appearance of the fibroadenoma resembled that of tumors growing in normal adult females. The mammary gland remained atrophic during both the slow and the accelerated phases of tumor growth, and so too with the other secondary sex expressions. In hypophysectomized rats estrone and progesterone, when combined, stimulated the growth of the tumor, and this growth was accelerated by the additional administration of lactogenic or growth hormones. None of these hormones, separately, stimulated the growth of the tumor. In ovariectomized rats other differences were demonstrated between the growth of the mammary gland and the fibroadenoma. Progesterone, injected alone, accelerated the growth of the tumor but not that of the mammary glands. The administration of phenolic estrogens exerted a biphasic effect on the growth of the tumor whilst that on the breast of its hosts was monophasic. With progressively increasing doses of these phenols there occurred primarily an augmentation of the rate of

  5. Variability in Migration Routes Influences Early Marine Survival of Juvenile Salmon Smolts.

    PubMed

    Furey, Nathan B; Vincent, Stephen P; Hinch, Scott G; Welch, David W

    2015-01-01

    Variability in animal migratory behavior is expected to influence fitness, but few empirical examples demonstrating this relationship exist. The initial marine phase in the migration of juvenile salmon smolts has been identified as a potentially critical life history stage to overall population productivity, yet how fine-scale migration routes may influence survival are unknown. Large-scale acoustic telemetry studies have estimated survival rates of outmigrant Pacific salmon smolts through the Strait of Georgia (SOG) along the British Columbian coastline to the Pacific Ocean, but these data have not been used to identify and characterize fine-scale movements. Data collected on over 850 sockeye salmon (Oncorhynchus nerka) and steelhead (Oncorhynchus mykiss) smolts detected at an array in the Strait of Georgia in 2004-2008 and 2010-2013 were analyzed to characterize migration routes and link movements to subsequent survival at an array 250 km further along the marine migration pathway. Both species exhibited disproportionate use of the most eastern route in the Strait of Georgia (Malaspina Strait). While many smolts moved across the northern Strait of Georgia acoustic array with no indication of long-term milling or large-scale east-to-west movements, large proportions (20-40% of sockeye and 30-50% of steelhead) exhibited a different behavior, apparently moving in a westward or counterclockwise pattern. Variability in migratory behavior for both species was linked to subsequent survival through the Strait of Georgia. Survival for both species was influenced by initial east-to-west location, and sockeye were further influenced by migration timing and duration of time spent near the northern Strait of Georgia array. Westward movements result in a net transport of smolts from Malaspina Strait to the Strait of Georgia, particularly for steelhead. Counterclockwise movements may be due to the currents in this area during the time of outmigration, and the higher proportion

  6. Variability in Migration Routes Influences Early Marine Survival of Juvenile Salmon Smolts

    PubMed Central

    Furey, Nathan B.; Vincent, Stephen P.; Hinch, Scott G.; Welch, David W.

    2015-01-01

    Variability in animal migratory behavior is expected to influence fitness, but few empirical examples demonstrating this relationship exist. The initial marine phase in the migration of juvenile salmon smolts has been identified as a potentially critical life history stage to overall population productivity, yet how fine-scale migration routes may influence survival are unknown. Large-scale acoustic telemetry studies have estimated survival rates of outmigrant Pacific salmon smolts through the Strait of Georgia (SOG) along the British Columbian coastline to the Pacific Ocean, but these data have not been used to identify and characterize fine-scale movements. Data collected on over 850 sockeye salmon (Oncorhynchus nerka) and steelhead (Oncorhynchus mykiss) smolts detected at an array in the Strait of Georgia in 2004–2008 and 2010–2013 were analyzed to characterize migration routes and link movements to subsequent survival at an array 250 km further along the marine migration pathway. Both species exhibited disproportionate use of the most eastern route in the Strait of Georgia (Malaspina Strait). While many smolts moved across the northern Strait of Georgia acoustic array with no indication of long-term milling or large-scale east-to-west movements, large proportions (20–40% of sockeye and 30–50% of steelhead) exhibited a different behavior, apparently moving in a westward or counterclockwise pattern. Variability in migratory behavior for both species was linked to subsequent survival through the Strait of Georgia. Survival for both species was influenced by initial east-to-west location, and sockeye were further influenced by migration timing and duration of time spent near the northern Strait of Georgia array. Westward movements result in a net transport of smolts from Malaspina Strait to the Strait of Georgia, particularly for steelhead. Counterclockwise movements may be due to the currents in this area during the time of outmigration, and the higher

  7. Attitudes Toward Juvenile Sex Offender Legislation: The Influence of Case-Specific Information.

    PubMed

    Campregher, Julia; Jeglic, Elizabeth L

    2016-01-01

    This study examined attitudes toward the application of adult sex offender legislation to juvenile sex offenders. Participants were randomly assigned to one of nine conditions. In the generic condition, the participants were asked to envision a generic juvenile sex offender, whereas in the manipulated conditions, participants read a vignette with three manipulated variables: offense type, victim age, and victim gender. Afterward, all participants (n = 978) completed questionnaires assessing perceptions of juvenile sex offenders and juvenile sex offender legislation. Overall, participants in the generic juvenile sex offender condition rated the perpetrator as more dangerous and more likely to reoffend than participants in the experimental conditions. Moreover, participants in the generic juvenile sex offender condition were more likely to endorse more punitive punishments and viewed perpetrators as "superpredators." When examining differences between the experimental conditions, participants reading vignettes with younger victims and male victims as well as vignettes with contact offenses were more likely to view the perpetrator as dangerous, likely to recidivate, as a "superpredator," and deserving of more punitive punishments. Implications for public policy as well as future research directions are discussed.

  8. Nitrite-induced alterations in sex steroids and thyroid hormones of Labeo rohita juveniles: effects of dietary vitamin E and L-tryptophan.

    PubMed

    Ciji, A; Sahu, N P; Pal, A K; Akhtar, M S

    2013-10-01

    An experiment was conducted to study the effect of sub-lethal nitrite exposure on sex steroids (testosterone and estradiol), cortisol and thyroid hormones (T3 and T4) of Labeo rohita juveniles. Fishes previously fed with normal or elevated levels of vitamin E (VE) and tryptophan for 60 days were exposed to sub-lethal nitrite for another 45 days with same feeding regime. There were nine treatment groups, viz. VE0TRP0-N, VE0TRP0+N, VE100TRP0-N, VE100TRP0+N, VE100TRP0.75+N, VE100TRP1.5+N, VE150TRP0+N, VE300TRP0+N and VE200TRP1+N. Except the groups VE0TRP0-N and VE100TRP0-N, all other groups were exposed to nitrite. At the end of the 45 days of nitrite exposure, serum samples were assayed for sex steroids, cortisol and thyroid hormones. The serum T3 and T4 levels decreased to the extent of 84.5 and 94.06%, respectively, upon nitrite exposure. Dietary supplementation with additional amounts of VE and tryptophan appears to reduce the decline of the production of T4. The serum testosterone and estradiol decreased 97.31 and 92.86%, respectively, upon nitrite exposure. Supplementation with additional amounts of VE was found to reverse nitrite-induced inhibition of testosterone and estradiol production. Serum cortisol increased upon nitrite exposure and unexposed (VE100-N) group showed lower levels, which were comparable to groups fed with elevated levels of VE. The overall results of the present study revealed that environmental nitrites have a negative impact on steroidogenesis, which can be overcome by dietary supplementation of elevated amounts of VE (minimum of 150 mg VE Kg diet(-1)) and to a lesser extent by tryptophan (only at the level of 1.5% of the diet).

  9. Initiation of metamorphosis and control of ecdysteroid biosynthesis in insects: The interplay of absence of Juvenile hormone, PTTH, and Ca(2+)-homeostasis.

    PubMed

    De Loof, Arnold; Vandersmissen, Tim; Marchal, Elisabeth; Schoofs, Liliane

    2015-06-01

    The paradigm saying that release of the brain neuropeptide big prothoracicotropic hormone (PTTH) initiates metamorphosis by activating the Torso-receptor/ERK pathway in larval prothoracic glands (PGs) is widely accepted nowadays. Upon ligand-receptor interaction Ca(2+) enters the PG cells and acts as a secondary messenger. Ecdysteroidogenesis results, later followed by apoptosis. Yet, some data do not fit in this model. In some species decapitated animals can still molt, even repeatedly, and metamorphose. PTTH does not universally occur in all insect species. PGs may also have other functions; PGs as counterpart of the vertebrate thymus? There are also small PTTHs. Finally, PTTH remains abundantly present in adults and plays a role in control of ecdysteroidogenesis (=sex steroid production) in gonads. This is currently documented only in males. This urges a rethinking of the PTTH-PG paradigm. The key question is: Why does PTTH-induced Ca(2+) entry only result in ecdysteroidogenesis and apoptosis in specific cells/tissues, namely the PGs and gonads? Indeed, numerous other neuropeptides also use Ca(2+) as secondary messenger. The recent rediscovery that in both invertebrates and vertebrates at least some isoforms of Ca(2+)-ATPase need the presence of an endogenous farnesol/juvenile hormone(JH)-like sesquiterpenoid for keeping cytosolic [Ca(2+)]i below the limit of apoptosis-induction, triggered the idea that it is not primarily PTTH, but rather the drop to zero of the JH titer that acts as the primordial initiator of metamorphosis by increasing [Ca(2+)]i. PTTH likely potentiates this effect but only in cells expressing Torso. PTTH: an evolutionarily ancient gonadotropin? Copyright © 2014 Elsevier Inc. All rights reserved.

  10. How do seasonality and host traits influence the distribution patterns of parasites on juveniles and adults of Columba livia?

    PubMed

    Amaral, Hugo Leonardo da Cunha; Bergmann, Fabiane Borba; Dos Santos, Paulo Roberto Silveira; Silveira, Tony; Krüger, Rodrigo Ferreira

    2017-08-30

    Parasites may influence host fitness and consequently exert a selective pressure on distinct phenotypes of the host population. This pressure can result in an evolutionary response, maintaining only individuals with certain traits in the population. The present study was aimed at identifying the morphological characteristics of juveniles and adults of Columba livia that may influence the distribution patterns of lice, Pseudolynchia canariensis and Haemoproteus columbae and how the populations of these parasites vary throughout the seasons of the year. Between July 2012 and July 2014, 377 specimens of C. livia were captured. We observed a significant increase in the mean intensities of infestation by pigeon flies and lice, as well as in species richness of ectoparasites during the warmest seasons, suggesting a reproductive synchrony between ectoparasites and host species. Bill length, body mass, and body length did not affect the infestation levels of ectoparasites on adults and juveniles of C. livia with three distinct plumage colors. In juveniles, plumage color affected only the mean intensity of infestation by lice, with Spread individuals as the most infested. This indicates that melanin in feathers was not an effective barrier against ectoparasites. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. The influence of pituitary, adrenal, and parathyroid hormones on hemostasis and thrombosis.

    PubMed

    Squizzato, Alessandro; Van Zaane, Bregje; Gerdes, Victor E A; Büller, Harry R

    2011-02-01

    Endocrine disorders can influence the hemostatic balance. Abnormal coagulation test results have been observed in patients with abnormal hormone levels. The present review updates the available evidence on the influence of pituitary, adrenal, and parathyroid hormones on the coagulation and the fibrinolytic system, and their possible clinical implications. The literature supports a possible relevant clinical effect of the imbalance between coagulation and fibrinolysis on thrombotic events in endogenous Cushing's syndrome. An effect on markers of coagulation and fibrinolysis has been shown for hyperprolactinemia, growth hormone excess or deficiency, exogenous hypercortisolism, pheochromocytoma, primary hyperaldosteronism, and hyperparathyroidism. However, the clinical relevance is still unproven. Until definitive evidence is available, clinicians should be aware of the possibility that endocrine disorders may be risk factors for thrombotic events.

  12. An isoform of Taiman that contains a PRD-repeat motif is indispensable for transducing the vitellogenic juvenile hormone signal in Locusta migratoria.

    PubMed

    Wang, Zhiming; Yang, Libin; Song, Jiasheng; Kang, Le; Zhou, Shutang

    2017-03-01

    Taiman (Tai) has been recently identified as the dimerizing partner of juvenile hormone (JH) receptor, Methoprene-tolerant (Met). However, the role of Tai isoforms in transducing vitellogenic signal of JH has not been determined. In this study, we show that the migratory locust Locusta migratoria has two Tai isoforms, which differ in an INDEL-1 domain with the PRD-repeat motif rich in histidine and proline at the C-terminus. Tai-A with the INDEL-1 is expressed at levels about 50-fold higher than Tai-B without the INDEL-1 in the fat body of vitellogenic adult females. Knockdown of Tai-A but not Tai-B results in a substantial reduction of vitellogenin expression in the fat body accompanied by the arrest of ovarian development and oocyte maturation, similar to that caused by depletion of both Tai isoforms. Either Tai-A or Tai-B combined with Met can induce target gene transcription in response to JH, but Tai-A appears to mediate a significantly higher transactivation. Our data suggest that the INDEL-1 domain plays a critical role in Tai function during reproduction as Tai-A appears be more active than Tai-B in transducing the vitellogenic JH signal in L. migratoria.

  13. Remating behavior in Anastrepha fraterculus (Diptera: Tephritidae) females is affected by male juvenile hormone analog treatment but not by male sterilization.

    PubMed

    Abraham, S; Liendo, M C; Devescovi, F; Peralta, P A; Yusef, V; Ruiz, J; Cladera, J L; Vera, M T; Segura, D F

    2013-06-01

    The sterile insect technique (SIT) has been proposed as an area-wide method to control the South American fruit fly, Anastrepha fraterculus (Wiedemann). This technique requires sterilization, a procedure that affects, along with other factors, the ability of males to modulate female sexual receptivity after copulation. Numerous pre-release treatments have been proposed to counteract the detrimental effects of irradiation, rearing and handling and increase SIT effectiveness. These include treating newly emerged males with a juvenile hormone mimic (methoprene) or supplying protein to the male's diet to accelerate sexual maturation prior to release. Here, we examine how male irradiation, methoprene treatment and protein intake affect remating behavior and the amount of sperm stored in inseminated females. In field cage experiments, we found that irradiated laboratory males were equally able to modulate female remating behavior as fertile wild males. However, females mated with 6-day-old, methoprene-treated males remated more and sooner than females mated with naturally matured males, either sterile or wild. Protein intake by males was not sufficient to overcome reduced ability of methoprene-treated males to induce refractory periods in females as lengthy as those induced by wild and naturally matured males. The amount of sperm stored by females was not affected by male irradiation, methoprene treatment or protein intake. This finding revealed that factors in addition to sperm volume intervene in regulating female receptivity after copulation. Implications for SIT are discussed.

  14. Enhancing male sexual success in a lekking fly (Anastrepha suspensa Diptera: Tephritidae) through a juvenile hormone analog has no effect on adult mortality.

    PubMed

    Pereira, Rui; Sivinski, John; Teal, Peter; Brockmann, Jane

    2010-11-01

    While defending lek-territories, male Anastrepha suspensa (Loew) produce chemical, acoustic and visual courtship signals. In the laboratory and under semi-natural conditions, topical application of the juvenile hormone analog methoprene doubles pheromone production and subsequently doubles sexual success. However, sexual signals and interactions are likely to be physiologically expensive and so result in higher male mortality. Comparison of males kept in isolation for 35 days, but provided daily with a potential mate or a rival male, revealed that both male- and female-interactors shortened focal-male lifespan. In addition, focal males were either treated with methoprene or not, then either provided with protein in their sucrose-based diet or not. Protein proved to similarly double sexual success and also resulted in longer male life spans in all of the interactor-categories. However, there was no evidence that methoprene induced hypersexuality resulted in higher rates of mortality, i.e., the longevity of males treated with methoprene did not significantly differ from untreated males in the same interactor/diet categories. This apparent lack of costs to a putatively sexually selected signal is unexpected but presents an opportunity to increase the sexual competence of sterile flies with few consequences to their survival following mass-release. Published by Elsevier Ltd.

  15. Juvenile Hormone Enhances Aversive Learning Performance in 2-Day Old Worker Honey Bees while Reducing Their Attraction to Queen Mandibular Pheromone

    PubMed Central

    McQuillan, H. James; Nakagawa, Shinichi; Mercer, Alison R.

    2014-01-01

    Previous studies have shown that exposing young worker bees (Apis mellifera) to queen mandibular pheromone (QMP) reduces their aversive learning performance, while enhancing their attraction to QMP. As QMP has been found to reduce the rate of juvenile hormone (JH) synthesis in worker bees, we examined whether aversive learning in 2-day old workers exposed to QMP from the time of adult emergence could be improved by injecting JH (10 µg in a 2 µl volume) into the haemolymph. We examined in addition, the effects of JH treatment on worker attraction to QMP, and on the levels of expression of amine receptor genes in the antennae, as well as in the mushroom bodies of the brain. We found that memory acquisition and 1-hour memory recall were enhanced by JH. In contrast, JH treatment reduced the bees’ attraction towards a synthetic strip impregnated with QMP (Bee Boost). Levels of expression of the dopamine receptor gene Amdop1 were significantly lower in the mushroom bodies of JH-treated bees than in bees treated with vehicle alone (acetone diluted with bee ringer). Expression of the octopamine receptor gene, Amoa1, in this brain region was also affected by JH treatment, and in the antennae, Amoa1 transcript levels were significantly lower in JH-treated bees compared to controls. The results of this study suggest that QMP’s effects on JH synthesis may contribute to reducing aversive learning performance and enhancing attraction to QMP in young worker bees. PMID:25390885

  16. Methyl farnesoate epoxidase (mfe) gene expression and juvenile hormone titers in the life cycle of a highly eusocial stingless bee, Melipona scutellaris.

    PubMed

    Cardoso-Júnior, Carlos Antônio Mendes; Silva, Renato Pereira; Borges, Naiara Araújo; de Carvalho, Washington João; Walter, S Leal; Simões, Zilá Luz Paulino; Bitondi, Marcia Maria Gentile; Ueira Vieira, Carlos; Bonetti, Ana Maria; Hartfelder, Klaus

    2017-08-01

    In social insects, juvenile hormone (JH) has acquired novel functions related to caste determination and division of labor among workers, and this is best evidenced in the honey bee. In contrast to honey bees, stingless bees are a much more diverse group of highly eusocial bees, and the genus Melipona has long called special attention due to a proposed genetic mechanism of caste determination. Here, we examined methyl farnesoate epoxidase (mfe) gene expression, encoding an enzyme relevant for the final step in JH biosynthesis, and measured the hemolymph JH titers for all life cycle stages of Melipona scutellaris queens and workers. We confirmed that mfe is exclusively expressed in the corpora allata. The JH titer is high in the second larval instar, drops in the third, and rises again as the larvae enter metamorphosis. During the pupal stage, mfe expression is initialy elevated, but then gradually drops to low levels before adult emergence. No variation was, however, seen in the JH titer. In adult virgin queens, mfe expression and the JH titer are significantly elevated, possibly associated with their reproductive potential. For workers we found that JH titers are lower in foragers than in nurse bees, while mfe expression did not differ. Stingless bees are, thus, distinct from honey bee workers, suggesting that they have maintained the ancestral gonadotropic function for JH. Hence, the physiological circuitries underlying a highly eusocial life style may be variable, even within a monophyletic clade such as the corbiculate bees. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. The juvenile hormone (JH) epoxide hydrolase gene in the honey bee (Apis mellifera) genome encodes a protein which has negligible participation in JH degradation.

    PubMed

    Mackert, Aline; Hartfelder, Klaus; Bitondi, Márcia Maria Gentile; Simões, Zilá Luz Paulino

    2010-09-01

    Epoxide hydrolases are multifunctional enzymes that are best known in insects for their role in juvenile hormone (JH) degradation. Enzymes involved in JH catabolism can play major roles during metamorphosis and reproduction, such as the JH epoxide hydrolase (JHEH), which degrades JH through hydration of the epoxide moiety to form JH diol, and JH esterase (JHE), which hydrolyzes the methyl ester to produce JH acid. In the honey bee, JH has been co-opted for additional functions, mainly in caste differentiation and in age-related behavioral development of workers, where the activity of both enzymes could be important for JH titer regulation. Similarity searches for jheh candidate genes in the honey bee genome revealed a single Amjheh gene. Sequence analysis, quantification of Amjheh transcript levels and Western blot assays using an AmJHEH-specific antibody generated during this study revealed that the AmJHEH found in the fat body shares features with the microsomal JHEHs from several insect species. Using a partition assay we demonstrated that AmJHEH has a negligible role in JH degradation, which, in the honey bee, is thus performed primarily by JHE. High AmJHEH levels in larvae and adults were related to the ingestion of high loads of lipids, suggesting that AmJHEH has a role in dietary lipid catabolism.

  18. Krüppel homolog 1 and E93 mediate Juvenile hormone regulation of metamorphosis in the common bed bug, Cimex lectularius

    PubMed Central

    Gujar, Hemant; Palli, Subba Reddy

    2016-01-01

    The common bed bug is an obligate hematophagous parasite of humans. We studied the regulation of molting and metamorphosis in bed bugs with a goal to identify key players involved. qRT-PCR studies on the expression of genes known to be involved in molting and metamorphosis showed high levels of Krüppel homolog 1 [Kr-h1, a transcription factor that plays key roles in juvenile hormone (JH) action] mRNA in the penultimate nymphal stage (N4). However, low levels of Kr-h1 mRNA were detected in the fifth and last nymphal stage (N5). Knockdown of Kr-h1 in N4 resulted in a precocious development of adult structures. Kr-h1 maintains the immature stage by suppressing E93 (early ecdysone response gene) in N4. E93 expression increases during the N5 in the absence of Kr-h1 and promotes the development of adult structures. Knockdown of E93 in N5 results in the formation of supernumerary nymphs. The role of JH in the suppression of adult structures through interaction with Kr-h1 and E93 was also studied by the topical application of JH analog, methoprene, to N5. Methoprene induced Kr-h1 and suppressed E93 and induced formation of the supernumerary nymph. These data show interactions between Kr-h1, E93 and JH in the regulation of metamorphosis in the bed bugs. PMID:27185064

  19. Proteome analysis of male accessory gland secretions in oriental fruit flies reveals juvenile hormone-binding protein, suggesting impact on female reproduction

    PubMed Central

    Wei, Dong; Li, Hui-Min; Tian, Chuan-Bei; Smagghe, Guy; Jia, Fu-Xian; Jiang, Hong-Bo; Dou, Wei; Wang, Jin-Jun

    2015-01-01

    In insects, the accessory gland proteins (Acps) secreted by male accessory glands (MAGs) account for the majority of seminal fluids proteins. Mixed with sperm, they are transferred to the female at mating and so impact reproduction. In this project, we identified 2,927 proteins in the MAG secretions of the oriental fruit fly Bactrocera dorsalis, an important agricultural pest worldwide, using LC-MS analysis, and all sequences containing open reading frames were analyzed using signalP. In total, 90 Acps were identified. About one third (26) of these 90 Acps had a specific functional description, while the other two thirds (64) had no functional description including dozens of new classes of proteins. Hence, several of these novel Acps were abundant in the MAG secretions, and we confirmed their MAG-specific expression by qPCR. Finally and interestingly, one of these novel proteins was functionally predicted as juvenile hormone-binding protein, suggesting the impact of Acps with reproductive events in the female. Our results will aid in the development of an experimental method to identify Acps in insects, and in turn this information with new Acps in B. dorsalis will pave the way of further exploration their function in reproduction and potential development as new insecticide targets. PMID:26582577

  20. Krüppel homolog 1 and E93 mediate Juvenile hormone regulation of metamorphosis in the common bed bug, Cimex lectularius.

    PubMed

    Gujar, Hemant; Palli, Subba Reddy

    2016-05-17

    The common bed bug is an obligate hematophagous parasite of humans. We studied the regulation of molting and metamorphosis in bed bugs with a goal to identify key players involved. qRT-PCR studies on the expression of genes known to be involved in molting and metamorphosis showed high levels of Krüppel homolog 1 [Kr-h1, a transcription factor that plays key roles in juvenile hormone (JH) action] mRNA in the penultimate nymphal stage (N4). However, low levels of Kr-h1 mRNA were detected in the fifth and last nymphal stage (N5). Knockdown of Kr-h1 in N4 resulted in a precocious development of adult structures. Kr-h1 maintains the immature stage by suppressing E93 (early ecdysone response gene) in N4. E93 expression increases during the N5 in the absence of Kr-h1 and promotes the development of adult structures. Knockdown of E93 in N5 results in the formation of supernumerary nymphs. The role of JH in the suppression of adult structures through interaction with Kr-h1 and E93 was also studied by the topical application of JH analog, methoprene, to N5. Methoprene induced Kr-h1 and suppressed E93 and induced formation of the supernumerary nymph. These data show interactions between Kr-h1, E93 and JH in the regulation of metamorphosis in the bed bugs.

  1. Structure-activity studies of allatostatin 4 on the inhibition of juvenile hormone biosynthesis by corpora allata: the importance of individual side chains and stereochemistry.

    PubMed

    Hayes, T K; Guan, X C; Johnson, V; Strey, A; Tobe, S S

    1994-01-01

    The production of juvenile hormone III (JH III) by the corpora allata of the cockroach Diploptera punctata is regulated in part by peptides originating from the brain. One group of these peptides, termed allatostatins, reversibly inhibits the biosynthesis of JH in vitro. Allatostatin 4 (AST4: Asp-Arg-Leu-Tyr-Ser-Phe-Gly-Leu-amide) is the smallest member of the AST family yet defined and was used as the benchmark peptide for these initial structure-activity studies. Two initial analog series of AST4 were examined for the ability of each analog to inhibit JH biosynthesis by corpora allata in vitro. Each analog series consisted of analogs that contained a single amino acid change from the native AST4 sequence. The first series contained Ala replacement analogs and the second contained analogs with D-amino acid replacements. The first analog series used Ala replacements to help indicate which amino acid side chains were most important for inhibition of JH biosynthesis. The most important side chain appeared to be Leu8 followed by Phe6 and Tyr4. Additionally, the D-amino acid series suggested that a secondary structural element(s) at the C-terminus of AST4 could be important to the biological activity.

  2. Proteome analysis of male accessory gland secretions in oriental fruit flies reveals juvenile hormone-binding protein, suggesting impact on female reproduction.

    PubMed

    Wei, Dong; Li, Hui-Min; Tian, Chuan-Bei; Smagghe, Guy; Jia, Fu-Xian; Jiang, Hong-Bo; Dou, Wei; Wang, Jin-Jun

    2015-11-19

    In insects, the accessory gland proteins (Acps) secreted by male accessory glands (MAGs) account for the majority of seminal fluids proteins. Mixed with sperm, they are transferred to the female at mating and so impact reproduction. In this project, we identified 2,927 proteins in the MAG secretions of the oriental fruit fly Bactrocera dorsalis, an important agricultural pest worldwide, using LC-MS analysis, and all sequences containing open reading frames were analyzed using signalP. In total, 90 Acps were identified. About one third (26) of these 90 Acps had a specific functional description, while the other two thirds (64) had no functional description including dozens of new classes of proteins. Hence, several of these novel Acps were abundant in the MAG secretions, and we confirmed their MAG-specific expression by qPCR. Finally and interestingly, one of these novel proteins was functionally predicted as juvenile hormone-binding protein, suggesting the impact of Acps with reproductive events in the female. Our results will aid in the development of an experimental method to identify Acps in insects, and in turn this information with new Acps in B. dorsalis will pave the way of further exploration their function in reproduction and potential development as new insecticide targets.

  3. Effects of methoprene, a juvenile hormone analog, on survival of various developmental stages, adult emergence, reproduction and behavior of Asian citrus psyllid, Diaphorina citri Kuwayama.

    PubMed

    Brar, Gurpreet S; Meyer, Wendy; Stelinski, Lukasz L

    2015-12-01

    The Asian citrus citrus psyllid, Diaphorina citri Kuwayama, transmits a bacterium that causes huanglongbing in citrus. Frequent and repeated use of neurotoxic insecticides against D. citri has resulted in the development of insecticide resistance. We evaluated the effects of the juvenile hormone analog methoprene on egg hatch, nymphal development, adult emergence, reproduction and behavior of D. citri. Methoprene significantly reduced the viability of eggs that were between 0 and 4 days old. Egg hatch of 0-48-h-old and 49-96-h-old eggs was 8 and 9%, respectively, when treated with 320 µg mL(-1) of methoprene. Methoprene caused significant mortality of first-, third- and fifth-instar D. citri nymphs and reduced adult emergence as compared with controls. Methoprene caused less than 5% adult emergence when first- and third-instar stages were treated, respectively, and less than 40% adult emergence when fifth instars were treated. Reduced fertility of females was observed when they emerged from methoprene-treated fifth instars. Methoprene was effective in reducing egg hatch, suppressing nymphal development and decreasing adult emergence of D. citri under laboratory conditions. Treatment of fifth instars reduced the fertility of females. Methoprene might be a possible tool for integrated management of D. citri. © 2015 Society of Chemical Industry.

  4. Juvenile hormone III suppresses forkhead of transcription factor in the fat body and reduces fat accumulation in the diapausing mosquito, Culex pipiens.

    PubMed

    Sim, Cheolho; Denlinger, David L

    2013-02-01

    Juvenile hormone (JH) controls diverse physiological and developmental events including diapause and nutrient metabolism. The focal point of endocrine regulation in adult reproductive diapause is initiated by a halt of JH synthesis. In diapausing females of the mosquito Culex pipiens, the other key molecular event is the signalling pathway from insulin to forkhead of transcription factor (FOXO). We hypothesized that a halt of JH synthesis is related to activation of FOXO, which results in increasing lipid reserves in the fat body at the onset of the diapause programme. In this study, the full-length sequence of the foxo gene in C. pipiens was characterized, and the protein abundance pattern of the foxo gene product was analyzed by immunoblotting and immunohistochemistry. FOXO was much more abundant in the fat body of diapausing females than in the fat body of nondiapausing females; much lower levels were present in other adult tissues. When we topically applied JH III to diapause-destined females, FOXO was suppressed, and fat accumulation was reduced, suggesting an interaction between JH synthesis and FOXO that is critical for expression of the diapause phenotype. © 2012 Royal Entomological Society.

  5. Juvenile hormone enhances aversive learning performance in 2-day old worker honey bees while reducing their attraction to queen mandibular pheromone.

    PubMed

    McQuillan, H James; Nakagawa, Shinichi; Mercer, Alison R

    2014-01-01

    Previous studies have shown that exposing young worker bees (Apis mellifera) to queen mandibular pheromone (QMP) reduces their aversive learning performance, while enhancing their attraction to QMP. As QMP has been found to reduce the rate of juvenile hormone (JH) synthesis in worker bees, we examined whether aversive learning in 2-day old workers exposed to QMP from the time of adult emergence could be improved by injecting JH (10 µg in a 2 µl volume) into the haemolymph. We examined in addition, the effects of JH treatment on worker attraction to QMP, and on the levels of expression of amine receptor genes in the antennae, as well as in the mushroom bodies of the brain. We found that memory acquisition and 1-hour memory recall were enhanced by JH. In contrast, JH treatment reduced the bees' attraction towards a synthetic strip impregnated with QMP (Bee Boost). Levels of expression of the dopamine receptor gene Amdop1 were significantly lower in the mushroom bodies of JH-treated bees than in bees treated with vehicle alone (acetone diluted with bee ringer). Expression of the octopamine receptor gene, Amoa1, in this brain region was also affected by JH treatment, and in the antennae, Amoa1 transcript levels were significantly lower in JH-treated bees compared to controls. The results of this study suggest that QMP's effects on JH synthesis may contribute to reducing aversive learning performance and enhancing attraction to QMP in young worker bees.

  6. Influence of thyrotropin-releasing hormone administration at birth on thermoregulation in lambs delivered by cesarean.

    PubMed

    Heasman, L; Clarke, L; Symonds, M E

    2000-11-01

    We examined the hypothesis that exogenous stimulation with thyrotropin-releasing hormone immediately before umbilical cord clamping can improve thermoregulation in near-term lambs delivered by cesarean. Twin lambs were injected with either saline solution alone (control, n = 12) or thyrotropin-releasing hormone in saline solution (n = 16) and were immediately placed in a warm (30 degrees C; n = 14) or cool (15 degrees C; n = 14) ambient temperature. In vivo measurements of temperature control (colonic temperature, oxygen consumption, and incidence of shivering) were then performed during the first 6 hours after birth, in conjunction with plasma thyroid hormone measurements. Brown adipose tissue was then sampled for measurement of uncoupling protein 1 abundance. Plasma triiodothyronine concentrations were significantly higher in lambs treated with thyrotropin-releasing hormone than in control lambs between 3 and 6 hours after birth, as were plasma thyroxine concentrations 1 and 5 hours after birth. Delivery temperature had no effect on plasma thyroid hormone concentrations. At 6 hours after birth the abundance of uncoupling protein 1 was higher in lambs treated with thyrotropin-releasing hormone than in control lambs. Lambs treated with thyrotropin-releasing hormone exhibited a lower incidence of shivering than did control lambs between 5 and 6 hours after birth, and an effect of ambient temperature on the incidence of shivering was observed only in the control group. From 3 to 6 hours after birth colonic temperature was significantly higher in cool-delivered lambs treated with thyrotropin-releasing hormone than in the control group. Oxygen consumption was higher in cool-delivered lambs than warm-delivered lambs, but this was not influenced by thyrotropin-releasing hormone. Irrespective of delivery temperature, lambs treated with thyrotropin-releasing hormone possessed more pericardial adipose tissue and hepatic glycogen than did control lambs. Thyrotropin

  7. Influence of thyroid hormone disruption on the incidence of shingles.

    PubMed

    Ajavon, A; Killian, D; Odom, R; Figliozzi, R W; Chen, F; Balish, M; Parmar, J; Freeman, R; Snitzer, J; Hsia, S V

    2015-12-01

    The reactivation of dormant alpha-human herpesvirus (αHHV) has been attributed to various causes often referred to as stressors. However, no clinical study investigating the relationship between stressors and reactivation exists in humans at this time. Herpes simplex virus type-1 (HSV-1), an important αHHV, was shown to have its gene expression and replication regulated by thyroid hormone (TH) using molecular biology approaches. Varicella zoster virus (VZV) is categorized in αHHV superfamily and shares similar homology with HSV-1. We hypothesize that a history of TH imbalance may be associated with the incidence of shingles (VZV reactivation). This current pilot study, based on a hospital medical claims database, was conducted as a retrospective case-controlled investigation to determine if a putative link between TH imbalance and incidence of shingles is present. An odds ratio of 2·95 with a χ 2 value of 51·74 was calculated for the total population diagnosed with TH disruption and shingles. Further analyses indicated that African American males exhibited a much higher chance of simultaneous diagnoses. These results show that a TH imbalance history may affect VZV reactivation at different incidence rates in different races and age groups.

  8. Influence of Thyroid Hormone Disruption on the Incidence of Shingles

    PubMed Central

    Ajavon, Amakoe; Killian, Dennis; Odom, Randy; Figliozzi, Robert W.; Chen, Feng; Balish, Matthew; Parmar, Jayesh; Freeman, Robert; Snitzer, Jack; Hsia, S. Victor

    2015-01-01

    SUMMARY The reactivation of dormant alpha-Human Herpes Virus (αHHV) has been attributed to various causes often referred to as stressors. However, no clinical study investigating the relationship between stressors and reactivation exists in humans at this time. Herpes Simplex Virus Type-1 (HSV-1), an important αHHV, was shown to have its gene expression and replication regulated by Thyroid hormone (TH) using molecular biology approaches. Varicella Zoster Virus (VZV) is categorized in αHHV superfamily and shares similar homology with HSV-1. We hypothesize that a history of TH imbalance may be associated with the incidence of shingles (VZV reactivation). This current pilot study, based on a hospital medical claim database, was conducted as a retrospective case-controlled investigation to determine if a putative link between TH imbalance and incidence of shingles is present. An OR of 2.95 with a Chi-square of 51.74 was calculated for the total population diagnosed with TH disruption and shingles. Further analyses indicated that African American males exhibited much higher chance of simultaneous diagnoses. These results showed that a TH imbalance history may affect VZV reactivation at different incidence rates in different races and age groups. PMID:26189668

  9. Brain sex differences and the organisation of juvenile social play behaviour.

    PubMed

    Auger, A P; Olesen, K M

    2009-06-01

    Juvenile social play behaviour is one of the earliest forms of non-mother directed social behaviour in rodents. Juvenile social play behaviour is sexually dimorphic, with males exhibiting higher levels compared to females, making it a useful model to study both social development and sexual differentiation of the brain. As with most sexually dimorphic behaviour, juvenile play behaviour is organised by neonatal steroid hormone exposure. The developmental organisation of juvenile play behaviour also appears to be influenced by the early maternal environment. This review will focus briefly on why and how rats play, some brain regions controlling play behaviour, and how neurotransmitters and the social environment converge within the developing brain to influence sexual differentiation of juvenile play behaviour.

  10. Brain sex differences and the organization of juvenile social play behavior

    PubMed Central

    Auger, Anthony P.; Olesen, Kristin M.

    2009-01-01

    Juvenile social play behavior is one of the earliest forms of non-mother directed social behavior in rodents. Juvenile social play behavior is sexually dimorphic, with males exhibiting higher levels compared to females, making it a useful model to study both social development and sexual differentiation of the brain. As most sexually dimorphic behavior, juvenile play behavior is organized by neonatal steroid hormone exposure. The developmental organization of juvenile play behavior also appears to be influenced by the early maternal environment. This review will focus briefly on why and how rats play, some brain regions controlling play behavior, and how neurotransmitters and the social environment converge within the developing brain to influence sexual differentiation of juvenile play behavior. PMID:19500222

  11. Women's experiences of hormonal therapy for breast cancer: exploring influences on medication-taking behaviour.

    PubMed

    Cahir, Caitriona; Dombrowski, Stephan U; Kelly, Catherine M; Kennedy, M John; Bennett, Kathleen; Sharp, Linda

    2015-11-01

    Five to 10 years of adjuvant hormonal therapy is recommended to prevent breast cancer recurrence. This study investigated modifiable influences on adjuvant hormonal therapy medication-taking behaviour (MTB) in women with stage I-III breast cancer. Semi-structured face-to-face interviews among women with stage I-III breast cancer prescribed adjuvant hormonal therapy purposively sampled by their MTB at two cancer centres. Thematic analysis was conducted based on the Framework approach, with the Theoretical Domains Framework (TDF) informing the analysis framework; the TDF is an integrative framework consisting of 14 domains of behavioural change to inform intervention design. Thirty-one women participated in interviews (14 adherent/persistent; 7 non-adherent/persistent; 10 non-persistent). Three domains identified both barriers and enablers to hormonal therapy MTB across the three MTB strata: beliefs about consequences, intentions and goals and behaviour regulation, but their influence was different across the strata. Other domains influenced individual MTB strata. Key enablers for adherent/persistent women were identified within the domain beliefs about consequences (breast cancer recurrence), intentions and goals (high-priority), beliefs about capabilities (side effects) and behaviour regulation (managing medication). Barriers were identified within the domain behaviour regulation (no routine), memory, attention and decision processes (forgetting) and environmental context and resources (stressors) for non-adherent/persistent women and intentions and goals (quality of life), behaviour regulation (temporal self-regulation), reinforcement, beliefs about consequences (non-necessity) and social influences (clinical support) for non-persistent women. This study identified modifiable influences on hormonal therapy MTB. Targeting these influences in clinical practice may improve MTB and hence survival in this population.

  12. Factors influencing the cognitive and neural effects of hormone treatment during aging in a rodent model

    PubMed Central

    Chisholm, Nioka C.; Juraska, Janice M.

    2013-01-01

    Whether hormone treatment alters brain structure or has beneficial effects on cognition during aging has recently become a topic of debate. Although previous research has indicated that hormone treatment benefits memory in menopausal women, several newer studies have shown no effect or detrimental effects. These inconsistencies emphasize the need to evaluate the role of hormones in protecting against age-related cognitive decline in an animal model. Importantly, many studies investigating the effects of estrogen and progesterone on cognition and related brain regions have used young adult animals, which respond differently than aged animals. However, when only the studies that have examined the effects of hormone treatment in an aging model are reviewed, there are still varied behavioral and neural outcomes. This article reviews some of the important factors that can influence the behavioral and neural outcomes of hormone treatment including the type of estrogen administered, whether or not estrogen is combined with progesterone and if so, the type of progesterone used, as well as the route, mode, and length of treatment. How these factors influence cognitive outcomes highlights the importance of study design and avoiding generalizations from a small number of studies. PMID:23419893

  13. Repeated, Intermittent Social Defeat across the Entire Juvenile Period Resulted in Behavioral, Physiological, Hormonal, Immunological, and Neurochemical Alterations in Young Adult Male Golden Hamsters.

    PubMed

    Yu, Wei-Chun; Liu, Ching-Yi; Lai, Wen-Sung

    2016-01-01

    The developing brain is vulnerable to social defeat during the juvenile period. As complements of human studies, animal models of social defeat provide a straightforward approach to investigating the functional and neurobiological consequences of social defeats. Taking advantage of agonist behavior and social defeat in male golden hamster, a set of 6 experiments was conducted to investigate the consequences at multiple levels in young adulthood resulting from repeated, intermittent social defeats or "social threats" across the entire juvenile period. Male hamsters at postnatal day 28 (P28) were randomly assigned to either the social defeat, "social threat", or arena control group, and they correspondingly received a series of nine social interaction trials (i.e., either social defeat, "social threat", or arena control conditions) from P33 to P66. At the behavioral level (Experiment 1), we found that repeated social defeats (but not "social threats") significantly impacted locomotor activity in the familiar context and social interaction in the familiar/unfamiliar social contexts. At the physiological and hormonal levels (Experiments 2 and 3), repeated social defeat significantly enhanced the cortisol and norepinephrine concentrations in blood. Enlargement of the spleen was also found in the social defeat and "social threat" groups. At the immunological level (Experiment 4), the social defeat group showed lower levels of pro-inflammatory cytokines in the hypothalamus and hippocampus but higher concentration of IL-6 in the striatum compared to the other two groups. At the neurochemical level (Experiment 5), the socially defeated hamsters mainly displayed reductions of dopamine, dopamine metabolites, and 5-HT levels in the striatum and decreased level of 5-HT in the hippocampus. In Experiment 6, an increase in the spine density of hippocampal CA1 pyramidal neurons was specifically observed in the "social threat" group. Collectively, our findings indicate that repeated

  14. Repeated, Intermittent Social Defeat across the Entire Juvenile Period Resulted in Behavioral, Physiological, Hormonal, Immunological, and Neurochemical Alterations in Young Adult Male Golden Hamsters

    PubMed Central

    Yu, Wei-Chun; Liu, Ching-Yi; Lai, Wen-Sung

    2016-01-01

    The developing brain is vulnerable to social defeat during the juvenile period. As complements of human studies, animal models of social defeat provide a straightforward approach to investigating the functional and neurobiological consequences of social defeats. Taking advantage of agonist behavior and social defeat in male golden hamster, a set of 6 experiments was conducted to investigate the consequences at multiple levels in young adulthood resulting from repeated, intermittent social defeats or “social threats” across the entire juvenile period. Male hamsters at postnatal day 28 (P28) were randomly assigned to either the social defeat, “social threat”, or arena control group, and they correspondingly received a series of nine social interaction trials (i.e., either social defeat, “social threat”, or arena control conditions) from P33 to P66. At the behavioral level (Experiment 1), we found that repeated social defeats (but not “social threats”) significantly impacted locomotor activity in the familiar context and social interaction in the familiar/unfamiliar social contexts. At the physiological and hormonal levels (Experiments 2 and 3), repeated social defeat significantly enhanced the cortisol and norepinephrine concentrations in blood. Enlargement of the spleen was also found in the social defeat and “social threat” groups. At the immunological level (Experiment 4), the social defeat group showed lower levels of pro-inflammatory cytokines in the hypothalamus and hippocampus but higher concentration of IL-6 in the striatum compared to the other two groups. At the neurochemical level (Experiment 5), the socially defeated hamsters mainly displayed reductions of dopamine, dopamine metabolites, and 5-HT levels in the striatum and decreased level of 5-HT in the hippocampus. In Experiment 6, an increase in the spine density of hippocampal CA1 pyramidal neurons was specifically observed in the “social threat” group. Collectively, our

  15. Environmental stressors influencing hormones and systems physiology in cattle

    PubMed Central

    2014-01-01

    Environmental stressors undoubtedly influence organismal biology, specifically the endocrine system that, in turn, impact cattle at the systems physiology level. Despite the significant advances in understanding the genetic determinants of the ideal dairy or beef cow, there is a grave lack of understanding of the systems physiology and effects of the environmental stressors that interfere with the endocrine system. This is a major problem because the lack of such knowledge is preventing advances in understanding gene-environment interactions and developing science-based solutions to these challenges. In this review, we synthesize the current knowledge on the nature of the major environmental stressors, such as climate (heat, cold, wind, and humidity), nutrition (feeds, feeding systems, and endocrine disruptors) and management (housing density and conditions, transportation, weaning practices). We summarize the impact of each one of these factors on cattle at the systems level, and provide solutions for the challenges. PMID:24996419

  16. Understanding the School Outcomes of Juvenile Offenders: An Exploration of Neighborhood Influences and Motivational Resources

    ERIC Educational Resources Information Center

    Chung, He Len; Mulvey, Edward P.; Steinberg, Laurence

    2011-01-01

    As a group, delinquent youth complete less education and show poor academic outcomes compared to their non-delinquent peers. To better understand pathways to school success, this study integrated individual- and neighborhood-level data to examine academic functioning among 833 White, Black, and Hispanic male juvenile offenders (age 14-17) living…

  17. Juvenile growth reduces the influence of epithelial sodium channels on myogenic tone in skeletal muscle arterioles.

    PubMed

    Kang, Lori S; Masilamani, Shyama; Boegehold, Matthew A

    2016-12-01

    Previous studies have documented that rapid juvenile growth is accompanied by functional changes in the arteriolar endothelium, but much less is known about functional changes in arteriolar smooth muscle over this period. In this study, we investigate the possible contribution of epithelial sodium channels (ENaC) to the myogenic behaviour of arterioles at two stages of juvenile growth. The effects of the ENaC inhibitor benzamil on different levels of myogenic tone were studied in isolated gracilis muscle arterioles from rats aged 21-28 days ("weanlings") and 42-49 days ("juveniles"). ENaC subunit expression in the arteriolar wall was also determined, and the interaction between ENaC and nitric oxide (NO) in regulating vascular tone was explored by combined use of benzamil and N(G) -monomethyl-l-arginine (l-NMMA). At physiological pressures, both steady-state myogenic tone and the dynamic adjustments in this tone triggered by acute pressure changes were less in juvenile arterioles than in weanling arterioles. α, β and γ ENaC protein was present in arterioles at both ages, but benzamil only had an effect on myogenic tone in weanling arterioles. In these vessels, benzamil increased, rather than decreased, myogenic tone, and this effect was prevented by l-NMMA or endothelial removal. These findings suggest that although ENaC is present in gracilis muscle arterioles of both weanling and juvenile rats, it is not obligatory for the genesis of myogenic activity in these vessels at either age. However, ENaC activity can significantly modulate the level of myogenic tone through stimulation of endothelial NO release at an early stage of growth. © 2016 John Wiley & Sons Australia, Ltd.

  18. Juvenile Arthritis

    MedlinePlus

    ... A Patient / Caregiver Diseases & Conditions Juvenile Arthritis Juvenile Arthritis Fast Facts Arthritis in children is treatable. It ... as fevers or rash. What is juvenile idiopathic arthritis? Several types of arthritis, all involving chronic (long- ...

  19. Influence of physical exercise on sex-hormone metabolism.

    PubMed

    Keizer, H A; Poortman, J; Bunnik, G S

    1980-05-01

    We have studied the effects of short-term exercise on the degradation rate of estradiol (E2) measured as the metabolic clearance rate (MCRE2). Six young women (mean age 20.7 yr) volunteered for this study in which we investigated the influence of a submaximal bicycle ergometer load on the MCRE2. All measurements were done in the morning of the 7th to 10th day of the menstrual cycle. [3H]estradiol 17 beta ([3H]E2) was administered intravenously at a constant rate by an infusion pump. During the exercise period on the bicycle ergometer (70% VO2max, 10 min) and the recovery period (25% VO2max, 30 min), several blood samples were taken in which the [3H]E2 concentration was estimated. The results showed a strong decrease in the MCRE2 (range 18-67%) at the end of the work load for all the volunteers. At the end of the recovery period, the MCR was still lower than the basal value (range 30-50%). The possible mechanisms and relevance of these exercise-induced MCR changes of estradiol are discussed.

  20. Sublethal effects of chlorantraniliprole on juvenile hormone levels and mRNA expression of JHAMT and FPPS genes in the rice stem borer, Chilo suppressalis.

    PubMed

    Xu, Beibei; Qian, Kun; Zhang, Nan; Miao, Lijun; Cai, Jingxuan; Lu, Mingxing; Du, Yuzhou; Wang, Jianjun

    2017-10-01

    Juvenile hormone (JH) regulates the development and reproduction of insects. The sublethal effects of chlorantraniliprole on JH levels and mRNA expression of JH acid methyltransferase gene (CsJHAMT) and farnesyl diphosphate synthase genes (CsFPPS1 and CsFPPS2) in Chilo suppressalis (Walker) were investigated. Exposure of sublethal concentrations of chlorantraniliprole (LC10 and LC30 ) to the third instar larvae of C. suppressalis significantly increased the JH levels in all developmental stages investigated including larvae 72 h after treatment, the first, third and fifth day of female pupae, as well as newly emerged, 12-h-old and 24-h-old female adults. A general trend of increased mRNA expression levels of CsJHAMT, CsFPPS1and CsFPPS2 was also observed in LC10 and LC30 treatment groups. Notably, the mRNA expression level of CsJHAMT significantly increased by 7.46-fold in the larvae 72 h after LC30 treatment. A significant increase of the mRNA expression levels of CsFPPS2 was also observed in the fifth day female pupae of LC10 and LC30 treatment groups (2.60-fold and 2.62-fold, respectively) as well as in 12-h-old female adults of the LC30 treatment group (3.45-fold). Sublethal concentrations of chlorantraniliprole might upregulate the expression of JH biosynthesis genes and in turn result in an increase of JH level in C. suppressalis. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  1. Linear growth in children suffering from juvenile idiopathic arthritis requiring steroid therapy: natural history and effects of growth hormone treatment on linear growth.

    PubMed

    Simon, D; Lucidarme, N; Prieur, A M; Ruiz, J C; Czernichow, P

    2001-01-01

    We assessed linear growth and final height retrospectively in a group of 24 patients suffering from juvenile idiopathic arthritis (JIA) during childhood who had received steroid therapy. In these patients, there was a significant loss of height of more than 2 standard deviations during the first years of the disease, which correlated positively with the duration of prednisone therapy. After remission of the disease and discontinuation of prednisone treatment, 70% of the patients achieved catch-up growth, although 30% showed a persistent loss of height. Their mean final height was strongly correlated with their mean height at the end of steroid therapy and was significantly different between the group of patients with catch-up growth and the group without catch-up growth. This pattern of growth observed in patients with JIA should help us to define strategies of growth hormone (GH) treatment in these patients in order to improve their final height. We have previously reported the beneficial effects on growth and body composition of 1 year of GH treatment in a group of 14 growth-retarded patients suffering from JIA who received glucocorticoid therapy. These patients (n = 13) were treated again with GH at the same dosage (0.46 mg/kg/week [0.07 mg/kg/day]) for another 3-year period. GH treatment markedly increased growth velocity in these patients, but had a minor effect on height SDS, suggesting that these children will remain short when adults. Starting GH therapy in these patients earlier after the onset of the disease may prevent growth deterioration and metabolic complications induced by chronic inflammation and long-term steroid therapy.

  2. Knockdown of the juvenile hormone receptor gene inhibits soldier-specific morphogenesis in the damp-wood termite Zootermopsis nevadensis (Isoptera: Archotermopsidae).

    PubMed

    Masuoka, Yudai; Yaguchi, Hajime; Suzuki, Ryutaro; Maekawa, Kiyoto

    2015-09-01

    The Methoprene-tolerant (Met) protein has been established as a juvenile hormone (JH) receptor. Knockdown of the Met gene caused precocious metamorphosis and suppression of ovarian development. However, the function of Met in caste development of social insects is unclear. In termites, JH acts as a central factor for caste development, especially for soldier differentiation, which involves two molts from workers via a presoldier stage. Increased JH titer in workers is needed for the presoldier molt, and the high JH titer is maintained throughout the presoldier period. Although presoldiers have the fundamental morphological features of soldiers, the nature of the cuticle is completely different from that of soldiers. We expected that JH signals via Met are involved in soldier-specific morphogenesis of the head and mandibles during soldier differentiation, especially in the presoldier period, in natural conditions. To test this hypothesis, we focused on soldier differentiation in an incipient colony of the damp-wood termite Zootermopsis nevadensis. Met homolog (ZnMet) expression in heads increased just after the presoldier molt. This high expression was reduced by ZnMet double stranded (dsRNA) injection before the presoldier molt. Although this treatment did not cause any morphological changes in presoldiers, it caused strong effects on soldiers, their mandibles being significantly shorter and head capsules smaller than those of control soldiers. Injection of ZnMet dsRNA throughout the presoldier stage did not affect the formation of soldier morphology, including cuticle formation. These results suggested that the rapid increase in ZnMet expression and subsequent activation of JH signaling just after the presoldier molt are needed for the formation of soldier-specific weapons. Therefore, besides its established role in insect metamorphosis, the JH receptor signaling also underlies soldier development in termites.

  3. Mosquito-specific microRNA-1890 targets the juvenile hormone-regulated serine protease JHA15 in the female mosquito gut

    PubMed Central

    Lucas, Keira J; Zhao, Bo; Roy, Sourav; Gervaise, Amanda L; Raikhel, Alexander S

    2015-01-01

    Females of the hematophagous mosquito species require a vertebrate blood meal to supply amino acids and other nutrients necessary for egg development, serving as the driving force for the spread of many vector-borne diseases in humans. Blood digestion utilizes both early and late phase serine proteases (SPs) that are differentially regulated at the transcriptional and post-transcriptional level. To uncover the regulatory complexity of SPs in the female mosquito midgut, we investigated involvement of miRNAs in regulating the juvenile hormone (JH)-controlled chymotrypsin-like SP, JHA15. We identified regulatory regions complementary to the mosquito-specific miRNA, miR-1890, within the 3′ UTR of JHA15 mRNA. The level of the JHA15 transcript is highest post eclosion and drastically declines post blood meal (PBM), exhibiting an opposite trend to miR-1890 that peaks at 24 h PBM. Depletion of miR-1890 results in defects in blood digestion, ovary development and egg deposition. JHA15 mRNA and protein levels are elevated in female mosquitoes with miR-1890 inhibition. JHA15 RNA interference in the miR-1890 depletion background alleviates miR-1890 depletion phenotypes. The miR-1890 gene is activated by the 20-hydroxyecdysone pathway that involves the ecdysone receptor and the early genes, E74B and Broad Z2. Our study suggests that miR-1890 controls JHA15 mRNA stability in a stage- and tissue- specific manner. PMID:26488481

  4. Juvenile hormone and methyl farnesoate production in cockroach embryos in relation to dorsal closure and the reproductive modes of different species of cockroaches.

    PubMed

    Li, Xinyi

    2007-12-01

    Juvenile hormone (JH), produced by the corpora allata (CA), is first detectable after dorsal closure, a conspicuous event in embryogenesis. The present research found that the timing of dorsal closure was consistently at about 45% of the total embryonic development time across most of the oviparous and ovoviviparous cockroach species examined. These included the ovoviviparous cockroaches Blaberus discoidalis, Byrsotria fumigata, Rhyparobia maderae, Nauphoeta cinerea, Phoetalia pallida, Schultesia lampyridiformis, and Panchlora nivea, as well as the oviparous cockroaches Blatta orientalis, Periplaneta americana, Eurycotis floridana, and Supella longipalpa. However, the only known viviparous cockroach Diploptera punctata completed dorsal closure at 20.8% of embryo development time. Methyl farnesoate (MF), the immediate precursor of JH III, is considered a functional molecule in crustaceans; however, in insects its function is still unclear. To understand the role of JH and MF in cockroach embryos, I compared JH and MF biosynthesis and release in several cockroach species of known phylogenetic relationships. Using a radiochemical assay, the present research showed that cockroach embryos representing all three reproductive modes produced and released both JH and MF, as previously shown for B. germanica, N. cinerea, and D. punctata. Members of a pair of embryonic CA from B. discoidalis, B. fumigata, R. maderae, and D. punctata were incubated with and without farnesol. MF accumulated in large amounts only in CA of R. maderae in the presence of farnesol, which indicates that control of the last step of biosynthesis of JH, conversion of MF into JH by MF epoxidase, is probably a rate-limiting step in this species.

  5. Comparative metabolism of branched-chain amino acids to precursors of juvenile hormone biogenesis in corpora allata of lepidopterous versus nonlepidopterous insects

    SciTech Connect

    Brindle, P.A.; Schooley, D.A.; Tsai, L.W.; Baker, F.C.

    1988-08-05

    Comparative studies were performed on the role of branched-chain amino acids (BCAA) in juvenile hormone (JH) biosynthesis using several lepidopterous and nonlepidopterous insects. Corpora cardiaca-corpora allata complexes (CC-CA, the corpora allata being the organ of JH biogenesis) were maintained in culture medium containing a uniformly /sup 14/C-labeled BCAA, together with (methyl-/sup 3/H)methionine as mass marker for JH quantification. BCAA catabolism was quantified by directly analyzing the medium for the presence of /sup 14/C-labeled propionate and/or acetate, while JHs were extracted, purified by liquid chromatography, and subjected to double-label liquid scintillation counting. Our results indicate that active BCAA catabolism occurs within the CC-CA of lepidopterans, and this efficiently provides propionyl-CoA (from isoleucine or valine) for the biosynthesis of the ethyl branches of JH I and II. Acetyl-CoA, formed from isoleucine or leucine catabolism, is also utilized by lepidopteran CC-CA for biosynthesizing JH III and the acetate-derived portions of the ethyl-branched JHs. In contrast, CC-CA of nonlepidopterans fail to catabolize BCAA. Consequently, exogenous isoleucine or leucine does not serve as a carbon source for the biosynthesis of JH III by these glands, and no propionyl-CoA is produced for genesis of ethyl-branched JHs. This is the first observation of a tissue-specific metabolic difference which in part explains why these novel homosesquiterpenoids exist in lepidopterans, but not in nonlepidopterans.

  6. Juvenile hormone facilitates the antagonism between adult reproduction and diapause through the methoprene-tolerant gene in the female Colaphellus bowringi.

    PubMed

    Liu, Wen; Li, Yi; Zhu, Li; Zhu, Fen; Lei, Chao-Liang; Wang, Xiao-Ping

    2016-07-01

    In insects, the process whereby juvenile hormone (JH) regulates short-day (SD)-induced reproductive diapause has been previously investigated. However, we still do not understand the mechanism by which JH regulates long-day (LD)-induced reproductive diapause. In this study, we use a cabbage beetle, Colaphellus bowringi, which is a serious pest of cruciferous vegetables in Asia capable of entering reproductive diapause under LD conditions, as a model to test whether JH regulates female reproductive diapause similar to the mechanism of SD-induced diapause. Our results showed that the JH analog (JHA) methoprene significantly induced ovarian development but inhibited lipid accumulation of diapause-destined adults. Meanwhile, the transcripts of the vitellogenin (Vg) genes were upregulated, whereas the expression of the fat synthesis and stress tolerance genes were downregulated. RNA interference of the JH candidate receptor gene methoprene-tolerant (Met) blocked JH-induced ovarian development and Vg transcription, suggesting a positive regulatory function for JH-Met signaling in reproduction. Furthermore, under reproduction-inducing conditions, Met depletion promoted a diapause-like phenotype, including arrested ovarian development and increased lipid storage, and stimulated the expression of diapause-related genes involved in lipid synthesis and stress tolerance, suggesting JH-Met signaling plays an important role in the inhibition of diapause. Accordingly, our data indicate that JH acts through Met to facilitate development of the reproductive system by upregulating Vg expression while inhibiting diapause by suppressing lipid synthesis and stress tolerance in the cabbage beetle. Combined with previous studies in SD-induced reproductive diapause, we conclude that JH may regulate female reproductive diapause using a conserved Met-dependent pathway, regardless of the length of the photoperiod inducing diapause in insects. Copyright © 2016 Elsevier Ltd. All rights

  7. Metabolic bone disease in juvenile Humboldt penguins (Spheniscus humboldti): investigation of ionized calcium, parathyroid hormone, and vitamin D3 as diagnostic parameters.

    PubMed

    Adkesson, Michael J; Langan, Jennifer N

    2007-03-01

    Three cases of metabolic bone disease (MBD) were identified in juvenile Humboldt penguins (Spheniscus humboldti) in a zoological collection. Diagnosis, monitoring, and treatment were challenging, in part because radiographs and traditional serum biochemistries did not provide adequate information to guide appropriate clinical management. Normal values for ionized calcium (iCa), 25-hydroxyvitamin D3 [25-(OH) D3], and parathyroid hormone (PTH) have not been reported for any species in the order Sphenisciformes. This study aimed to establish reference ranges for these parameters to provide a method for assessing clinical cases of MBD and other disease processes. iCa was measured in 33 healthy adult birds from two zoological collections by using a portable clinical analyzer. iCa also was measured from 14 of these birds at a commercial laboratory. Mean and standard deviation were determined to be 1.21 +/- 0.09 and 1.29 +/- 0.10 mmol/L, respectively. Limited data exist on iCa in avian species, but these results are consistent with other reports and provide a useful clinical parameter. Analysis of PTH and 25-(OH) D3 was performed at a commercial laboratory on samples from 14 healthy adult penguins in one collection. Means and standard deviations for PTH and 25-(OH) D3 were 0.8 +/- 0.3 pmol/L and 3.7 +/- 2.4 nmol/L, respectively. These results are near the minimal functional detectable limits of the assays; raising uncertainty about the validity and usefulness of currently available PTH and 25-(OH) D3 tests in this species.

  8. The Influence of Sodium- and Calcium-Regulatory Hormone Interventions on Adipocytokines in Obesity and Diabetes

    PubMed Central

    Vaidya, Anand; Underwood, Patricia C.; Annes, Justin P.; Sun, Bei; Williams, Gordon H.; Forman, John P.; Williams, Jonathan S.

    2012-01-01

    Objective The renin-angiotensin-aldosterone system (RAAS), vitamin D, and parathyroid hormone have all been implicated as regulators of adipocytokines and inflammation. We evaluated human interventional study protocols to investigate whether controlled modulations of these calcium- and sodium-regulatory hormones could influence adipocytokines and inflammation in obesity and diabetes. Methods Post-hoc analyses of two separate human protocols (Protocol 1, n=14; Protocol 2, n=24) conducted in a clinical research setting after rigorous control of diet, posture, medications, and diurnal rhythm, were performed. Protocol 1 evaluated obese hypertensives with vitamin D deficiency who received an infusion of angiotensin II (AngII) before and after 1 month of vitamin D3 therapy. Protocol 2 evaluated obese subjects with type 2 diabetes who also received AngII. Adipocytokines and inflammatory markers were measured before and after vitamin D3 therapy, and also before and after infusions of AngII. Results Vitamin D3 therapy significantly raised 25(OH)D and 1,25(OH)2D concentrations, and lowered parathyroid hormone, but had no effect on concentrations of adiponectin, resistin, leptin, IL-6, PAI-1, urinary TGFβ1, or HOMA-IR. AngII infusions, despite significant elevations in blood pressure and serum aldosterone, did not influence adipocytokine concentrations in either protocol. Conclusion In contrast to prior studies conducted in healthy populations, or those that could not control major regulators of the RAAS or adipocytokines, we observed that robust modulations in calcium- and sodium-regulatory hormones did not influence adipocytokines or inflammation in obesity or diabetes. Adipose-tissue physiology in these conditions may alter the hormonal regulation of inflammatory parameters. PMID:23142162

  9. [Influence of growth hormone (GH) and nutrition on neonatal growth].

    PubMed

    Díaz-Gómez, N M; Doménech Martínez, E; Barroso Guerrero, F; Cortabarria Bayona, C; Rico Sevillano, J

    1997-01-01

    At present, growth regulating factors in the transition from fetal to postnatal life remain unknown. The purpose of this study was to analyze the influence of GH and nutrition on neonatal growth. Serum and 24-hour urine GH levels, various anthopometric variables and daily energy and nutrient intake were measured in appropriate (AGA), large (LGA) and small for gestational age (SGA) newborn infants. These variables were measured at 1 (n = 98), 3 (n = 41) and 5 weeks of postnatal age (n = 8). The highest GH levels at the 1st week of postnatal life were obtained in preterm SGA infants (GHs: 61.4 +/- 20.0 microUI/m; GHu: 18.6 +/- 10.3 ng/kg/24 h). GH levels decreased in preterm infants, so that differences between groups failed to be significant at the third and fifth weeks of postnatal life. Urinary GH excretion did not show significant variations in the control group during the study (1st wk 3.0 +/- 3.5; 3rd wk 2.3 +/- 2.7; 5th wk 3.2 +/- 4.7 ng/kg/24 h). Daily protein intake had a direct relationship with both triceps skinfold and weight and head perimeter increase. SGA preterm infants showed a higher fat increase compared to AGA preterm infants. Serum and urinary GH levels were not related to the anthopometric variables studied. There are differences in GH secretion and body composition between SGA and AGA preterm infants. GH probably does not contribute to neonatal growth.

  10. Green tea proanthocyanidins cause impairment of hormone-regulated larval development and reproductive fitness via repression of juvenile hormone acid methyltransferase, insulin-like peptide and cytochrome P450 genes in Anopheles gambiae sensu stricto.

    PubMed

    Muema, Jackson M; Nyanjom, Steven G; Mutunga, James M; Njeru, Sospeter N; Bargul, Joel L

    2017-01-01

    Successful optimization of plant-derived compounds into control of nuisance insects would benefit from scientifically validated targets. However, the close association between the genotypic responses and physiological toxicity effects mediated by these compounds remains underexplored. In this study, we evaluated the sublethal dose effects of proanthocyanidins (PAs) sourced from green tea (Camellia sinensis) on life history traits of Anopheles gambiae (sensu stricto) mosquitoes with an aim to unravel the probable molecular targets. Based on the induced phenotypic effects, genes selected for study targeted juvenile hormone (JH) biosynthesis, signal transduction, oxidative stress response and xenobiotic detoxification in addition to vitellogenesis in females. Our findings suggest that chronic exposure of larval stages (L3/L4) to sublethal dose of 5 ppm dramatically extended larval developmental period for up to 12 days, slowed down pupation rates, induced abnormal larval-pupal intermediates and caused 100% inhibition of adult emergence. Further, females exhibited significant interference of fecundity and egg hatchability relative to controls (p < 0.001). Using reverse transcription quantitative polymerase chain reaction (RT-qPCR), our findings show that PA-treated larvae exhibited significant repression of AgamJHAMT (p < 0.001), AgamILP1 (p < 0.001) and AgamCYP6M2 (p < 0.001) with up-regulation of Hsp70 (p < 0.001). Females exposed as larvae demonstrated down-regulation of AgamVg (p = 0.03), AgamILP1 (p = 0.009), AgamCYP6M2 (p = 0.05) and AgamJHAMT (p = 0.02). Our findings support that C. sinensis proanthocyanidins affect important vectorial capacity components such as mosquito survival rates and reproductive fitness thus could be potentially used for controlling populations of malaria vectors.

  11. Green tea proanthocyanidins cause impairment of hormone-regulated larval development and reproductive fitness via repression of juvenile hormone acid methyltransferase, insulin-like peptide and cytochrome P450 genes in Anopheles gambiae sensu stricto

    PubMed Central

    Nyanjom, Steven G.; Mutunga, James M.; Njeru, Sospeter N.; Bargul, Joel L.

    2017-01-01

    Successful optimization of plant-derived compounds into control of nuisance insects would benefit from scientifically validated targets. However, the close association between the genotypic responses and physiological toxicity effects mediated by these compounds remains underexplored. In this study, we evaluated the sublethal dose effects of proanthocyanidins (PAs) sourced from green tea (Camellia sinensis) on life history traits of Anopheles gambiae (sensu stricto) mosquitoes with an aim to unravel the probable molecular targets. Based on the induced phenotypic effects, genes selected for study targeted juvenile hormone (JH) biosynthesis, signal transduction, oxidative stress response and xenobiotic detoxification in addition to vitellogenesis in females. Our findings suggest that chronic exposure of larval stages (L3/L4) to sublethal dose of 5 ppm dramatically extended larval developmental period for up to 12 days, slowed down pupation rates, induced abnormal larval-pupal intermediates and caused 100% inhibition of adult emergence. Further, females exhibited significant interference of fecundity and egg hatchability relative to controls (p < 0.001). Using reverse transcription quantitative polymerase chain reaction (RT-qPCR), our findings show that PA-treated larvae exhibited significant repression of AgamJHAMT (p < 0.001), AgamILP1 (p < 0.001) and AgamCYP6M2 (p < 0.001) with up-regulation of Hsp70 (p < 0.001). Females exposed as larvae demonstrated down-regulation of AgamVg (p = 0.03), AgamILP1 (p = 0.009), AgamCYP6M2 (p = 0.05) and AgamJHAMT (p = 0.02). Our findings support that C. sinensis proanthocyanidins affect important vectorial capacity components such as mosquito survival rates and reproductive fitness thus could be potentially used for controlling populations of malaria vectors. PMID:28301607

  12. Influence of externally attached transmitters on the swimming performance of juvenile white sturgeon

    USGS Publications Warehouse

    Counihan, T.D.; Frost, C.N.

    1999-01-01

    We measured the critical swimming speed of juvenile white sturgeons Acipenser transmontanus equipped with externally attached dummy ultrasonic transmitters and of untagged control fish in the laboratory. White sturgeons ranging from 31.9 to 37.0 cm fork length were subjected to one of three treatments: control (handled but not tagged), tag attached below the dorsal fin, and tag attached with the anterior insertion point between the fourth and fifth dorsal scutes. Although transmitters were of recommended weight, we found that the swimming performance of tagged white sturgeons was significantly less than that of untagged control fish. Swimming performance of tagged fish was not differentially affected by tag location. Our results suggest that data from ultrasonic telemetry studies of externally tagged juvenile white sturgeons should be interpreted with caution due to the reduced swimming performance caused by external transmitters.

  13. Influence of externally attached trasmitters on the swimming performance of juvenile white sturgeon

    USGS Publications Warehouse

    Counihan, T.D.; Frost, C.N.

    1999-01-01

    We measured the critical swimming speed of juvenile white sturgeons Acipenser transmontanus equipped with externally attached dummy ultrasonic transmitters and of untagged control fish in the laboratory. White sturgeons ranging from 31.9 to 37.0 cm fork length were subjected to one of three treatments: Control (handled but not tagged), tag attached below the dorsal fin, and tag attached with the anterior insertion point between the fourth and fifth dorsal scutes. Although transmitters were of recommended weight, we found that the swimming performance of tagged white sturgeons was significantly less than that of untagged control fish. Swimming performance of tagged fish was not differentially affected by tag location. Our results suggest that data from ultrasonic telemetry studies of externally tagged juvenile white sturgeons should be interpreted with caution due to the reduced swimming performance caused by external transmitters.

  14. Climate-driven coral reorganisation influences aggressive behaviour in juvenile coral-reef fishes

    NASA Astrophysics Data System (ADS)

    Kok, Judith E.; Graham, Nicholas A. J.; Hoogenboom, Mia O.

    2016-06-01

    Globally, habitat degradation is altering the abundance and diversity of species in a variety of ecosystems. This study aimed to determine how habitat degradation, in terms of changing coral composition under climate change, affected abundance, species richness and aggressive behaviour of juveniles of three damselfishes ( Pomacentrus moluccensis, P. amboinensis and Dischistodus perspicillatus, in order of decreasing reliance on coral). Patch reefs were constructed to simulate two types of reefs: present-day reefs that are vulnerable to climate-induced coral bleaching, and reefs with more bleaching-robust coral taxa, thereby simulating the likely future of coral reefs under a warming climate. Fish communities were allowed to establish naturally on the reefs during the summer recruitment period. Climate-robust reefs had lower total species richness of coral-reef fishes than climate-vulnerable reefs, but total fish abundance was not significantly different between reef types (pooled across all species and life-history stages). The nature of aggressive interactions, measured as the number of aggressive chases, varied according to coral composition; on climate-robust reefs, juveniles used the substratum less often to avoid aggression from competitors, and interspecific aggression became relatively more frequent than intraspecific aggression for juveniles of the coral-obligate P. moluccensis. This study highlights the importance of coral composition as a determinant of behaviour and diversity of coral-reef fishes.

  15. Influence of ovarian hormones on endocrine activity of gonadotroph cells in the adenohypophysis of lambs during the postnatal transition to prepuberty.

    PubMed

    Wańkowska, Marta; Polkowska, Jolanta; Misztal, Tomasz; Romanowicz, Katarzyna

    2010-08-01

    There is juvenile hiatus during maturation of larger mammals with relatively long life spans. Using histomorphological and functional criteria we describe the feedback mechanisms which could play a role in the regulation of the gonadotrophic axis during the postnatal transition to the quiescent prepubertal period in sheep. The aim of this study was to determine the influence of ovarian factors on the endocrine activity of gonadotroph cells, the site of synthesis, storage and release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH), in adenohypophyses of weanling and weaned prepubertal lambs. The examination was made in (i) 9-week-old infantiles, suckling lambs undergoing weaning, ovary-intact (OVI) and ovariectomised (OVX) at the 6th week of age, and (ii) 16-week-old juveniles OVI and OVX at the 12th week of age (n=5 per group). Changes in gonadotrophs were assayed with hybridohistochemistry, immunohistochemistry and radioimmunoassay. The percentage of the adenohypophyseal area (PA) occupied by gonadotrophs containing LHbeta-mRNA and immunoreactive for LHbeta was lower (P<0.05), whereas the PA occupied by cells containing FSHbeta-mRNA and immunoreactive for FSHbeta was higher (P<0.05) in the 16-week-old OVI lambs in comparison with the 9-week-old ones. The mean concentration and basal level of LH in the peripheral blood plasma were greater (P<0.05) in the 16-week-old OVI lambs in comparison with the 9-week-old group, whereas the circulating FSH was not different. In the OVX 9-week-old lambs, the PA occupied by gonadotrophs containing LHbeta-mRNA and the plasma LH concentration, basal level, pulse frequency and amplitude were greater (P<0.05), whereas the PA occupied by cells immunoreactive for LHbeta was lower (P<0.05) in comparison with the OVI group. In the OVX 16-week-old lambs, the PA occupied by gonadotrophs containing LHbeta-mRNA and immunoreactive for LHbeta, the LH plasma concentration, basal level and pulse frequency were (P<0.05) greater

  16. Determine the Influence of Time Held in “Knockdown” Anesthesia on Survival and Stress of Surgically Implanted Juvenile Salmonids

    SciTech Connect

    Woodley, Christa M.; Wagner, Katie A.; Knox, Kasey M.

    2012-01-31

    The Juvenile Salmon Acoustic Telemetry System (JSATS) was developed for the U.S. Army Corp of Engineers Portland District (USACE) to address questions related to survival and performance measures of juvenile salmonids as they pass through the Federal Columbia River Power System (FCRPS). Researchers using JSATS acoustic transmitters (ATs) were tasked with standardizing the surgical implantation procedure to ensure that the stressors of handling and surgery on salmonids were consistent and less likely to cause effects of tagging in survival studies. Researchers questioned whether the exposure time in 'knockdown' anesthesia (or induction) to prepare fish for surgery could influence the survival of study fish (CBSPSC 2011). Currently, fish are held in knockdown anesthesia after they reach Stage 4 anesthesia until the completion of the surgical implantation of a transmitter, varies from 5 to 15 minutes for studies conducted in the Columbia Basin. The Columbia Basin Surgical Protocol Steering Committee (CBSPSC ) expressed concern that its currently recommended 10-minute maximum time limit during which fish are held in anesthetic - tricaine methanesulfonate (MS-222, 80 mg L-1 water) - could increase behavioral and physiological costs, and/or decrease survival of outmigrating juvenile salmonids. In addition, the variability in the time fish are held at Stage 4 could affect the data intended for direct comparison of fish within or among survival studies. Under the current recommended protocol, if fish exceed the 10-minute time limit, they are to be released without surgical implantation, thereby increasing the number of fish handled and endangered species 'take' at the bypass systems for FCRPS survival studies.

  17. Influence of pH on the acute toxicity of ammonia to juvenile freshwater mussels (fatmucket, Lampsilis siliquoidea).

    PubMed

    Wang, Ning; Erickson, Russell J; Ingersoll, Christopher G; Ivey, Christopher D; Brunson, Eric L; Augspurger, Tom; Barnhart, M Christopher

    2008-05-01

    The objective of the present study was to evaluate the influence of pH on the toxicity of ammonia to juvenile freshwater mussels. Acute 96-h ammonia toxicity tests were conducted with 10-d-old juvenile mussels (fatmucket, Lampsilis siliquoidea) at five pH levels ranging from 6.5 to 9.0 in flow-through diluter systems at 20 degrees C. Acute 48-h tests with amphipods (Hyalella azteca) and 96-h tests with oligochaetes (Lumbriculus variegatus) were conducted concurrently under the same test conditions to determine the sensitivity of mussels relative to these two commonly tested benthic invertebrate species. During the exposure, pH levels were maintained within 0.1 of a pH unit and ammonia concentrations were relatively constant through time (coefficient of variation for ammonia concentrations ranged from 2 to 30% with a median value of 7.9%). The median effective concentrations (EC50s) of total ammonia nitrogen (N) for mussels were at least two to six times lower than the EC50s for amphipods and oligochaetes, and the EC50s for mussels decreased with increasing pH and ranged from 88 mg N/L at pH 6.6 to 0.96 mg N/L at pH 9.0. The EC50s for mussels were at or below the final acute values used to derive the U.S. Environmental Protection Agency's acute water quality criterion (WQC). However, the quantitative relationship between pH and ammonia toxicity to juvenile mussels was similar to the average relationship for other taxa reported in the WQC. These results indicate that including mussel toxicity data in a revision to the WQC would lower the acute criterion but not change the WQC mathematical representation of the relative effect of pH on ammonia toxicity.

  18. Influence of pH on the acute toxicity of ammonia to juvenile freshwater mussels (fatmucket, Lampsills siliquoidea)

    USGS Publications Warehouse

    Wang, N.; Erickson, R.J.; Ingersoll, C.G.; Ivey, C.D.; Brunson, E.L.; Augspurger, T.; Barnhart, M.C.

    2008-01-01

    The objective of the present study was to evaluate the influence of pH on the toxicity of ammonia to juvenile freshwater mussels. Acute 96-h ammonia toxicity tests were conducted with 10-d-old juvenile mussels (fatmucket, Lampsilis siliquoidea) at five pH levels ranging from 6.5 to 9.0 in flow-through diluter systems at 20??C. Acute 48-h tests with amphipods (Hyalella azteca) and 96-h tests with oligochaetes (Lumbriculus variegatus) were conducted concurrently under the same test conditions to determine the sensitivity of mussels relative to these two commonly tested benthic invertebrate species. During the exposure, pH levels were maintained within 0.1 of a pH unit and ammonia concentrations were relatively constant through time (coefficient of variation for ammonia concentrations ranged from 2 to 30% with a median value of 7.9%). The median effective concentrations (EC50s) of total ammonia nitrogen (N) for mussels were at least two to six times lower than the EC50s for amphipods and oligochaetes, and the EC50s for mussels decreased with increasing pH and ranged from 88 mg N/L at pH 6.6 to 0.96 mg N/L at pH 9.0. The EC50s for mussels were at or below the final acute values used to derive the U.S. Environmental Protection Agency's acute water quality criterion (WQC). However, the quantitative relationship between pH and ammonia toxicity to juvenile mussels was similar to the average relationship for other taxa reported in the WQC. These results indicate that including mussel toxicity data in a revision to the WQC would lower the acute criterion but not change the WQC mathematical representation of the relative effect of pH on ammonia toxicity. ?? 2008 SETAC.

  19. SEASONAL VARIATION IN PLASMA SEX STEROID CONCENTRATION IN JUVENILE ALLIGATORS

    EPA Science Inventory

    Seasonal variation in plasma sex steroid concentrations is common in mature vertebrates, and is occasionally seen in juvenile animals. In this study, we examine the seasonal pattern of sex hormone concentration in juvenile American alligators (Alligator mississippiensis) and make...

  20. SEASONAL VARIATION IN PLASMA SEX STEROID CONCENTRATION IN JUVENILE ALLIGATORS

    EPA Science Inventory

    Seasonal variation in plasma sex steroid concentrations is common in mature vertebrates, and is occasionally seen in juvenile animals. In this study, we examine the seasonal pattern of sex hormone concentration in juvenile American alligators (Alligator mississippiensis) and make...

  1. Growth hormone therapy influences endothelial function in children with renal failure.

    PubMed

    Lilien, Marc R; Schröder, Cornelis H; Levtchenko, Elena N; Koomans, Hein A

    2004-07-01

    Endothelial dysfunction, an early step in atherogenesis, is prevalent in children with renal insufficiency. Endothelial dysfunction in growth hormone deficiency is reversed by growth hormone (rhGH) therapy. Renal failure induces growth hormone resistance at the receptor and post-receptor level, which can be overcome by rhGH therapy. This study investigates the influence of rhGH therapy in children with renal failure on flow-mediated dilation (FMD) of the brachial artery, a marker of endothelial function. We studied 8 patients, who were on rhGH for at least 6 months, and 8 healthy children for comparison. FMD of the brachial artery was measured non-invasively as the percentage increase in diameter during post-ischemic hyperemia. Patients were studied at baseline, after 4 weeks interruption of rhGH therapy, and 4 weeks after resumption of therapy. FMD was significantly lower in patients (4.7%) than healthy controls (13.8%) ( P=0.01). During the administration of rhGH, FMD was significantly higher (3.9%) than during interruption of the treatment (1.4%) ( P=0.04). Our data support the theory that a disturbance in the GH-IGF axis contributes to the endothelial dysfunction of renal failure. Treatment with rhGH not only improves growth but may also favorably influence the risk for atherogenesis.

  2. The influence of sex hormones on seizures in dogs and humans.

    PubMed

    Van Meervenne, Sofie A E; Volk, Holger A; Matiasek, Kaspar; Van Ham, Luc M L

    2014-07-01

    Epilepsy is the most common chronic neurological disorder in both humans and dogs. The effect of sex hormones on seizures is well documented in human medicine. Catamenial epilepsy is defined as an increase in frequency and severity of seizures during certain periods of the menstrual cycle. Oestradiol increases seizure activity and progesterone is believed to exhibit a protective effect. The role of androgens is controversial and there is a lack of research focusing on androgens and epilepsy. Indeed, little is known about the influence of sex hormones on epilepsy in dogs. Sterilisation is believed to improve seizure control, but no systematic research has been conducted in this field. This review provides an overview of the current literature on the influence of sex hormones on seizures in humans. The literature on idiopathic epilepsy in dogs was assessed to identify potential risk factors related to sex and sterilisation status. In general, there appears to be an over-representation of male dogs with idiopathic epilepsy but no explanation for this difference in prevalence between sexes has been reported. In addition, no reliable conclusions can be drawn on the effect of sterilisation due to the lack of focused research and robust scientific evidence.

  3. Novel NAD+-Farnesal Dehydrogenase from Polygonum minus Leaves. Purification and Characterization of Enzyme in Juvenile Hormone III Biosynthetic Pathway in Plant.

    PubMed

    Seman-Kamarulzaman, Ahmad-Faris; Mohamed-Hussein, Zeti-Azura; Ng, Chyan Leong; Hassan, Maizom

    2016-01-01

    Juvenile Hormone III is of great concern due to negative effects on major developmental and reproductive maturation in insect pests. Thus, the elucidation of enzymes involved JH III biosynthetic pathway has become increasing important in recent years. One of the enzymes in the JH III biosynthetic pathway that remains to be isolated and characterized is farnesal dehydrogenase, an enzyme responsible to catalyze the oxidation of farnesal into farnesoic acid. A novel NAD+-farnesal dehydrogenase of Polygonum minus was purified (315-fold) to apparent homogeneity in five chromatographic steps. The purification procedures included Gigacap S-Toyopearl 650M, Gigacap Q-Toyopearl 650M, and AF-Blue Toyopearl 650ML, followed by TSK Gel G3000SW chromatographies. The enzyme, with isoelectric point of 6.6 is a monomeric enzyme with a molecular mass of 70 kDa. The enzyme was relatively active at 40°C, but was rapidly inactivated above 45°C. The optimal temperature and pH of the enzyme were found to be 35°C and 9.5, respectively. The enzyme activity was inhibited by sulfhydryl agent, chelating agent, and metal ion. The enzyme was highly specific for farnesal and NAD+. Other terpene aldehydes such as trans- cinnamaldehyde, citral and α- methyl cinnamaldehyde were also oxidized but in lower activity. The Km values for farnesal, citral, trans- cinnamaldehyde, α- methyl cinnamaldehyde and NAD+ were 0.13, 0.69, 0.86, 1.28 and 0.31 mM, respectively. The putative P. minus farnesal dehydrogenase that's highly specific towards farnesal but not to aliphatic aldehydes substrates suggested that the enzyme is significantly different from other aldehyde dehydrogenases that have been reported. The MALDI-TOF/TOF-MS/MS spectrometry further identified two peptides that share similarity to those of previously reported aldehyde dehydrogenases. In conclusion, the P. minus farnesal dehydrogenase may represent a novel plant farnesal dehydrogenase that exhibits distinctive substrate specificity towards

  4. Novel NAD+-Farnesal Dehydrogenase from Polygonum minus Leaves. Purification and Characterization of Enzyme in Juvenile Hormone III Biosynthetic Pathway in Plant

    PubMed Central

    Mohamed-Hussein, Zeti-Azura; Ng, Chyan Leong

    2016-01-01

    Juvenile Hormone III is of great concern due to negative effects on major developmental and reproductive maturation in insect pests. Thus, the elucidation of enzymes involved JH III biosynthetic pathway has become increasing important in recent years. One of the enzymes in the JH III biosynthetic pathway that remains to be isolated and characterized is farnesal dehydrogenase, an enzyme responsible to catalyze the oxidation of farnesal into farnesoic acid. A novel NAD+-farnesal dehydrogenase of Polygonum minus was purified (315-fold) to apparent homogeneity in five chromatographic steps. The purification procedures included Gigacap S-Toyopearl 650M, Gigacap Q-Toyopearl 650M, and AF-Blue Toyopearl 650ML, followed by TSK Gel G3000SW chromatographies. The enzyme, with isoelectric point of 6.6 is a monomeric enzyme with a molecular mass of 70 kDa. The enzyme was relatively active at 40°C, but was rapidly inactivated above 45°C. The optimal temperature and pH of the enzyme were found to be 35°C and 9.5, respectively. The enzyme activity was inhibited by sulfhydryl agent, chelating agent, and metal ion. The enzyme was highly specific for farnesal and NAD+. Other terpene aldehydes such as trans- cinnamaldehyde, citral and α- methyl cinnamaldehyde were also oxidized but in lower activity. The Km values for farnesal, citral, trans- cinnamaldehyde, α- methyl cinnamaldehyde and NAD+ were 0.13, 0.69, 0.86, 1.28 and 0.31 mM, respectively. The putative P. minus farnesal dehydrogenase that’s highly specific towards farnesal but not to aliphatic aldehydes substrates suggested that the enzyme is significantly different from other aldehyde dehydrogenases that have been reported. The MALDI-TOF/TOF-MS/MS spectrometry further identified two peptides that share similarity to those of previously reported aldehyde dehydrogenases. In conclusion, the P. minus farnesal dehydrogenase may represent a novel plant farnesal dehydrogenase that exhibits distinctive substrate specificity

  5. In silico and bio assay of juvenile hormone analogs as an insect growth regulator against Galleria mellonella (wax moth) - Part I.

    PubMed

    Sharma, Priyanka; Thakur, Sunil; Awasthi, Pamita

    2016-05-01

    Juvenile hormone (JH) analogs are nowadays in use to control harmful pests. In order to develop new bioactive molecules as potential pesticides, we have incorporated different active structural features like sulfonamide, aromatic rings, amide group, and amino acid moiety to the base structure. We have screened a series of designed novel JH analogs against JH receptor protein (jhbpGm-2RCK) of Galleria mellonella in comparison to commercial insect growth regulators (IGRs) - Pyriproxyfen (T1) and Fenoxycarb (T2). All analogs exhibit the binding energy profile comparable to commercial IGRs. Based upon these results, a series of sulfonamide-based JHAs (T3-T8) as IGRs have been synthesized and characterized. Further, the efficacy of synthesized analogs (T3-T8) and commercial IGRs (Pyriproxyfen and Fenoxycarb) has been assessed against fourth instars larvae of G. mellonella under the laboratory conditions. LC50 values of all the analogs (T1-T8) against the fourth instars larvae were 9.99, 10.12, 24.76, 30.73, 38.45, 34.15, 34.14, 19.48 ppm and the LC90 153.27, 131.69, 112.15, 191.46, 427.02, 167.13, 217.10, 172.00 ppm, respectively. Among these analogs, N-(1-isopropyl-2-oxo-3-aza-3-N-ethyl-pentanyl)-p-toluene sulfonamide (T8) and N-(1-isopropyl-2-oxo-3-aza-3-N-ethyl-pentanyl) benzene sulfonamide (T7) exhibited the good pest larval mortality at different exposure periods (in hours) and different concentrations (in ppm) in comparison to in use IGRs- T1 and T2. Bio assay results are supported by docking at higher concentration. The present investigation clearly exhibits that analog T8 could serve as a potential IGR in comparison to in use IGRs (T1 and T2). The results are promising and provide new array of synthetic chemicals that may be utilized as IGRs.

  6. The influence of androgenic steroid hormones on female aggression in ‘atypical’ mammals

    PubMed Central

    French, Jeffrey A.; Mustoe, Aaryn C.; Cavanaugh, Jon; Birnie, Andrew K.

    2013-01-01

    Dimorphism on dominance and agonistic behaviour in mammals tends to be strongly biased toward males. In this review, we focus on a select few species of mammals in which females are as or more aggressive than males, and/or are dominant to males, and explore the role of androgenic hormones in mediating this important difference. While the data are not as clear-cut as those published on traditional laboratory mammals, our review highlights important endocrine substrates for both organizational and activational influences of steroids on female aggressive behaviour. We highlight areas in which further observations and experiments are crucial, especially the potential facilitative effects of androgens on female aggression. Finally, new and innovative techniques, including molecular genetics and receptor pharmacology, portend important insights into the ways in which androgenic hormones regulate aggressive behaviour in ‘atypical’ female mammals. PMID:24167314

  7. The influence of androgenic steroid hormones on female aggression in 'atypical' mammals.

    PubMed

    French, Jeffrey A; Mustoe, Aaryn C; Cavanaugh, Jon; Birnie, Andrew K

    2013-01-01

    Dimorphism on dominance and agonistic behaviour in mammals tends to be strongly biased toward males. In this review, we focus on a select few species of mammals in which females are as or more aggressive than males, and/or are dominant to males, and explore the role of androgenic hormones in mediating this important difference. While the data are not as clear-cut as those published on traditional laboratory mammals, our review highlights important endocrine substrates for both organizational and activational influences of steroids on female aggressive behaviour. We highlight areas in which further observations and experiments are crucial, especially the potential facilitative effects of androgens on female aggression. Finally, new and innovative techniques, including molecular genetics and receptor pharmacology, portend important insights into the ways in which androgenic hormones regulate aggressive behaviour in 'atypical' female mammals.

  8. EFFECT OF ACUTE STRESS ON PLASMA CONCENTRATIONS OF SEX AND STRESS HORMONES IN JUVENILE ALLIGATORS LIVING IN CONTROL AND CONTAMINATED LAKES

    EPA Science Inventory

    Environmental contaminants can act as stressors, inducing elevated circulating concentrations of stress hormones such as corticosterone and cortisol. Development in contaminated eggs has been reported to modify circulating sex steroid hormone concentrations in alligators (Alligat...

  9. EFFECT OF ACUTE STRESS ON PLASMA CONCENTRATIONS OF SEX AND STRESS HORMONES IN JUVENILE ALLIGATORS LIVING IN CONTROL AND CONTAMINATED LAKES

    EPA Science Inventory

    Environmental contaminants can act as stressors, inducing elevated circulating concentrations of stress hormones such as corticosterone and cortisol. Development in contaminated eggs has been reported to modify circulating sex steroid hormone concentrations in alligators (Alligat...

  10. How type of parturition and health status influence hormonal and metabolic profiles in newborn foals.

    PubMed

    Panzani, S; Comin, A; Galeati, G; Romano, G; Villani, M; Faustini, M; Veronesi, M C

    2012-04-01

    Thyroid hormones, insulin growth factor I (IGF-I) and non-esterified fatty acids (NEFA) represent important hormonal and metabolic factors associated with perinatal growth and maturation. Their action could be influenced by the type of parturition and the health status of the foal and therefore the aim of this work is to evaluate their plasma concentrations in newborn foals during the first 2 wks of life. Three groups of subjects were enrolled: 15 healthy foals born by spontaneous parturition, 24 healthy foals born by induced parturition and 26 pathologic foals. From each of the healthy foals, blood was collected at 10, 20 and 30 minutes, 3 and 12 hours from birth, daily from Day 1 to Day 7, and at Day 10 and 14 of life. In pathologic foals samples were collected twice a day from the day of admission at the hospital until the day of discharge or death. Thyroid hormones (T3 and T4) and IGF-I were analyzed by radioimmunoassay and NEFA by enzymatic-colorimetric methods. In all the three groups a declining trend of T3 and T4 plasma concentrations was detectable, with lower levels in the pathologic group compared to healthy foals. Spontaneous foals showed higher levels of T3 at 7 d compared to induced foals, while T4 levels were higher in spontaneous vs. induced foals before 6 h of life, at three and seven days. IGF-I showed increasing plasma concentrations in all three considered groups. No differences were found between healthy and pathologic foals. NEFA in spontaneous and induced healthy foals showed a declining trend with higher levels during the first hours of life. Pathologic foals presented higher levels compared to spontaneous foals only at 24 h and 10 d. These data suggest that the type of foaling could influence the reference ranges for thyroid hormones. Moreover, pathologic foals showed some hormonal and metabolic differences related to their health status. Above all changes of thyroid hormones levels, early in postnatal life, could be a cause, and not only a

  11. Hormonal and dietary influences on true fractional calcium absorption in women: role of obesity

    PubMed Central

    Sukumar, D.; Schneider, S. H.; Schlussel, Y.; Brolin, R. E.; Taich, L.

    2014-01-01

    Summary The goal in this study was to examine the hormonal and dietary predictors of true fractional Ca absorption (TFCA) in adult women and to determine whether TFCA differs due to body weight. Results showed that TFCA is higher in obese individuals and dietary fat, estradiol, and 1,25-dihydroxy vitamin D are the most significant positive predictors of TFCA in adult women. Introduction Calcium absorption is an important determinant of calcium balance and is influenced by several factors. Previous studies have identified that age, intake of protein, fat and fiber, and hormones such as 1, 25-dihyroxyvitamin D (1,25(OH)2D3) influence absorption. The determinants of TFCA using the double isotope method, the gold standard estimate of absorption, have not been examined previously in adult women nor has the role of obesity been addressed. Methods In this study, we examined the hormonal and dietary predictors of TFCA in adult women with a wide range of age, body weights, and nutrient intake. TFCA was measured using dual stable isotope (42Ca and 43Ca) technique. Serum was analyzed for bone-regulating hormones, and dietary information was obtained through food records. The independent dietary factors and hormonal predictors (25-hydroxyvitamin D, 1,25(OH)2D3, parathyroid hormone, and estradiol) of TFCA were analyzed using multiple regression analysis. Results Two hundred twenty-nine women aged 54±11 years old (24–75 years) and with BMI of 31±7.0 kg/m2 were eligible and were categorized into tertiles of body mass index (BMI) into leaner, overweight, and obese. In the entire group of women, total fat intake, estradiol, and 1,25 (OH)2D3 are significant positive predictors (p<0.05). As expected, age is a significant negative predictor of TFCA (R2=26%). TFCA is higher in obese women compared to non-obese women (p<0.05). Conclusion Together, these data show that dietary fat is the most significant positive predictor of TFCA which may have implications for dietary intake for

  12. Influence of thyrotrophin-releasing hormone on thermoregulation in newborn lambs.

    PubMed

    Bird, J A; Clarke, L; Symonds, M E

    1998-01-01

    This study examined the effect of thyrotrophin-releasing hormone (TRH) administration on thermoregulation in the newborn. Twin lambs were either delivered near-term by caesarean section or born vaginally at term. Colonic temperature, O2 consumption, CO2 production, breathing and heart rates, plus plasma thyroid hormone and nonesterified fatty acid (NEFA) concentrations and thermogenic activity (i.e. GDP binding) of brown adipose tissue (BAT) were measured. In caesarean section delivered lambs colonic temperature decreased rapidly after birth, a response that was greater in the group designated for TRH treatment, in which colonic temperature fell to below 36.0 degrees C at 80 min of life, prior to TRH administration. At this age colonic temperature had been restored to a mean of 38.70 degrees C in controls. TRH had no influence on the composition or thermogenic activity of BAT. The incidence of shivering was not influenced by TRH, but treated lambs maintained a higher rate of O2 consumption and ventilation compared with controls after colonic temperature had been restored to 38.56 degrees C. TRH appeared to promote fat oxidation as O2 consumption remained unchanged and CO2 production declined by a greater rate in treated lambs, resulting in a lower respiratory quotient compared to controls. Heart rate and plasma concentrations of NEFA increased following TRH administration although this did not result in values greater than controls. Normothermic lambs born vaginally had BAT with a greater thermogenic activity, higher plasma thyroid hormone and NEFA concentrations compared with caesarean section delivered lambs, but a thermogenic response was not observed to TRH despite a rise in thyroid hormone concentrations. In conclusion, TRH can improve thermoregulation, an effect that could be linked to an increase in fat oxidation.

  13. Influence of age on pulsatile luteinizing hormone release and responsiveness of the gonadotrophs to sex hormone feedback in men.

    PubMed

    Deslypere, J P; Kaufman, J M; Vermeulen, T; Vogelaers, D; Vandalem, J L; Vermeulen, A

    1987-01-01

    The influence of aging on serum LH and testosterone (T) pulse frequency and gonadotroph sensitivity to androgen and estrogen feedback was studied in young (less than 55 yr old) and elderly (greater than 65 yr) Trappist monks. LH pulse frequency (sampling interval, 20 min) was significantly lower [0.25 +/- 0.03 (+/- SEM) vs. 0.38 +/- 0.02 pulses/h; P less than 0.01] in elderly (n = 21) than in young monks (n = 27); the pulse amplitudes were similar. Similarly, T pulse frequency was lower in the elderly than in the young monks (0.13 +/- 0.04 vs. 0.23 +/- 0.02 pulses/h; P less than 0.01). In elderly men, the hypothalamo-pituitary complex was more sensitive to 5 alpha-androstan-17 beta-ol-3-one feedback, as determined by the decrease in serum LH and T levels. Moreover, during 5 alpha-androstan-17 beta-ol-3-one (125 mg/day, percutaneously, for 10 days) administration, the LH response to LHRH (100 micrograms, iv) was significantly higher in the elderly men compared to the pretreatment response. During estradiol (1.5 mg/day, percutaneously for 10 days) administration, the LH response to LHRH was decreased in the elderly men, but unchanged in the young men, suggesting greater responsiveness to estradiol in the elderly men. We conclude that in aged men, decreased testicular androgen secretion is not exclusively the consequence of a primary testicular alteration, but that important changes occur in hypothalamo-pituitary function, specifically decreased LH pulse frequency and increased LH responsiveness to sex hormone feedback.

  14. The influence of hormone therapies on type I and II endometrial cancer: A nationwide cohort study.

    PubMed

    Mørch, Lina S; Kjaer, Susanne K; Keiding, Niels; Løkkegaard, Ellen; Lidegaard, Øjvind

    2016-03-15

    The influence of hormone therapy (HT) on risk for endometrial cancer is still casting which type of HT the clinicians recommend. It is unrevealed if HT has a differential influence on Type I versus Type II endometrial tumors, and little is known about the influence of, e.g., different routes of administration and about the influence of tibolone. We followed all Danish women aged 50-79 years without previous cancer or hysterectomy (n = 914,595) during 1995-2009. From the National Prescription Register, we computed HT exposures as time-dependent covariates. Incident endometrial cancers (n = 6,202) were identified from the National Cancer Registry: 4,972 Type I tumors and 500 Type II tumors. Incidence rate ratios (RRs) and 95% confidence intervals (Cls) were estimated by Poisson regression. Compared with women never on HT, the RR of endometrial cancer was increased with conjugated estrogen: 4.27 (1.92-9.52), nonconjugated estrogen: 2.00 (1.87-2.13), long cycle combined therapy: 2.89 (2.27-3.67), cyclic combined therapy: 2.06 (1.88-2.27), tibolone 3.56 (2.94-4.32), transdermal estrogen: 2.77 (2.12-3.62) and vaginal estrogen: 1.96 (1.77-2.17), but not with continuous combined therapy: 1.02 (0.87-1.20). In contrast, the risk of Type II tumors appeared decreased with continuous combined therapy: 0.45 (0.20-1.01), and estrogen therapy implied a nonsignificantly altered risk of 1.43 (0.85-2.41). Our findings support that continuous combined therapy is risk free for Type I tumors, while all other hormone therapies increase risk. In contrast, Type II endometrial cancer was less convincingly associated with hormone use, and continuous combined therapy appeared to decrease the risk. © 2015 UICC.

  15. Maternal and environmental influences on egg size and juvenile life-history traits in Pacific salmon

    PubMed Central

    Braun, Douglas C; Patterson, David A; Reynolds, John D

    2013-01-01

    Life-history traits such as fecundity and offspring size are shaped by investment trade-offs faced by mothers and mediated by environmental conditions. We use a 21-year time series for three populations of wild sockeye salmon (Oncorhynchus nerka) to test predictions for such trade-offs and responses to conditions faced by females during migration, and offspring during incubation. In years when their 1100 km upstream migration was challenged by high water discharges, females that reached spawning streams had invested less in gonads by producing smaller but not fewer eggs. These smaller eggs produced lighter juveniles, and this effect was further amplified in years when the incubation water was warm. This latter result suggests that there should be selection for larger eggs to compensate in populations that consistently experience warm incubation temperatures. A comparison among 16 populations, with matching migration and rearing environments but different incubation environments (i.e., separate spawning streams), confirmed this prediction; smaller females produced larger eggs for their size in warmer creeks. Taken together, these results reveal how maternal phenotype and environmental conditions can shape patterns of reproductive investment and consequently juvenile fitness-related traits within and among populations. PMID:23789081

  16. Habitat selection influences sex distribution, morphology, tissue biochemistry, and parasite load of juvenile coho salmon in the West Fork Smith River, Oregon

    EPA Science Inventory

    Given the strong influence of water temperature on salmonid physiology and behavior, in the summers of 2004 and 2005 we studied juvenile male and female coho salmon Oncorhynchus kisutch in two reaches of Oregon’s West Fork Smith River with different thermal profiles. Our goals we...

  17. Home versus School Environments and Their Influences on the Affective and Behavioral States of African American, Hispanic, and Caucasian Juvenile Offenders

    ERIC Educational Resources Information Center

    Caldwell, Roslyn M.; Sturges, Susan M.; Silver, N. Clayton

    2007-01-01

    We examined and compared the influence of home and school environments to the affective (anxiety and depression) and behavioral (impulsivity and compliance) states of 626 African American, Caucasian, and Hispanic adjudicated juvenile offenders. African Americans showed the strongest relationship between their home environment and compliance.…

  18. The influence of fall-spawning coho salmon (Oncorhynchus kisutch) on growth and production of juvenile coho salmon rearing in beaver ponds on the Copper River Delta, Alaska.

    Treesearch

    Dirk W. Lang; Gordon H. Reeves; James D. Hall; Mark S. Wipfli

    2006-01-01

    This study examined the influence of fall-spawning coho salmon (Oncorhynchrcs kisutch) on the density, growth rate, body condition, and survival to outmigration of juvenile coho salmon on the Copper River Delta, Alaska, USA. During the fall of 1999 and 2000, fish rearing in beaver ponds that received spawning salmon were compared with fish from...

  19. Habitat selection influences sex distribution, morphology, tissue biochemistry, and parasite load of juvenile coho salmon in the West Fork Smith River, Oregon

    EPA Science Inventory

    Given the strong influence of water temperature on salmonid physiology and behavior, in the summers of 2004 and 2005 we studied juvenile male and female coho salmon Oncorhynchus kisutch in two reaches of Oregon’s West Fork Smith River with different thermal profiles. Our goals we...

  20. Influence of Green Tides in Coastal Nursery Grounds on the Habitat Selection and Individual Performance of Juvenile Fish

    PubMed Central

    Murillo, Laurence; Randon, Marine; Lebot, Clément

    2017-01-01

    Coastal ecosystems, which provide numerous essential ecological functions for fish, are threatened by the proliferation of green macroalgae that significantly modify habitat conditions in intertidal areas. Understanding the influence of green tides on the nursery function of these ecosystems is essential to determine their potential effects on fish recruitment success. In this study, the influence of green tides on juvenile fish was examined in an intertidal sandy beach area, the Bay of Saint-Brieuc (Northwestern France), during two annual cycles of green tides with varying levels of intensity. The responses of three nursery-dependent fish species, the pelagic Sprattus sprattus (L.), the demersal Dicentrarchus labrax (L.) and the benthic Pleuronectes platessa L., were analysed to determine the effects of green tides according to species-specific habitat niche and behaviour. The responses to this perturbation were investigated based on habitat selection and a comparison of individual performance between a control and an impacted site. Several indices on different integrative scales were examined to evaluate these responses (antioxidant defence capacity, muscle total lipid, morphometric condition and growth). Based on these analyses, green tides affect juvenile fish differently according to macroalgal density and species-specific tolerance, which is linked to their capacity to move and to their distribution in the water column. A decreasing gradient of sensitivity was observed from benthic to demersal and pelagic fish species. At low densities of green macroalgae, the three species stayed at the impacted site and the growth of plaice was reduced. At medium macroalgal densities, plaice disappeared from the impacted site and the growth of sea bass and the muscle total lipid content of sprat were reduced. Finally, when high macroalgal densities were reached, none of the studied species were captured at the impacted site. Hence, sites affected by green tides are less

  1. Influence of Green Tides in Coastal Nursery Grounds on the Habitat Selection and Individual Performance of Juvenile Fish.

    PubMed

    Le Luherne, Emilie; Le Pape, Olivier; Murillo, Laurence; Randon, Marine; Lebot, Clément; Réveillac, Elodie

    2017-01-01

    Coastal ecosystems, which provide numerous essential ecological functions for fish, are threatened by the proliferation of green macroalgae that significantly modify habitat conditions in intertidal areas. Understanding the influence of green tides on the nursery function of these ecosystems is essential to determine their potential effects on fish recruitment success. In this study, the influence of green tides on juvenile fish was examined in an intertidal sandy beach area, the Bay of Saint-Brieuc (Northwestern France), during two annual cycles of green tides with varying levels of intensity. The responses of three nursery-dependent fish species, the pelagic Sprattus sprattus (L.), the demersal Dicentrarchus labrax (L.) and the benthic Pleuronectes platessa L., were analysed to determine the effects of green tides according to species-specific habitat niche and behaviour. The responses to this perturbation were investigated based on habitat selection and a comparison of individual performance between a control and an impacted site. Several indices on different integrative scales were examined to evaluate these responses (antioxidant defence capacity, muscle total lipid, morphometric condition and growth). Based on these analyses, green tides affect juvenile fish differently according to macroalgal density and species-specific tolerance, which is linked to their capacity to move and to their distribution in the water column. A decreasing gradient of sensitivity was observed from benthic to demersal and pelagic fish species. At low densities of green macroalgae, the three species stayed at the impacted site and the growth of plaice was reduced. At medium macroalgal densities, plaice disappeared from the impacted site and the growth of sea bass and the muscle total lipid content of sprat were reduced. Finally, when high macroalgal densities were reached, none of the studied species were captured at the impacted site. Hence, sites affected by green tides are less

  2. [The influence of 24-epibrassidinole on the hormone status of wheat plants under sodium chloride].

    PubMed

    Aval'baev, A M; Iuldashev, R A; Fatkhutdinova, R A; Urusov, F A; Safutdinova, Iu V; Shakirova, F M

    2010-01-01

    We studied the influence of the preconditioning of wheat germ (Triticum aestivum L.) with 0.4 microM 24-epibrassidinole (EB) on the growth and hormone status of plants under the influence of 2% NaCl. The preconditioning with EB promoted the lowering of the extent of the damaging influence of pickling on the growth of germs. The important contribution to the realization of the protective action of EB in the preconditioning of plants is probably that of its ability to lower the level of stress-induced abscisic acid accumulation and the decrease in the content of indole-acetic acid. At the same time, the cytokinin concentration in plants preconditioned with EB under pickling was practically the same as in plants without stress. This fact combined with data about the ability of EB to induce the increase in cytokinin content in wheat, obtained before, allowed us to assume that the protective action of EB on plants is connected, first of all, with the prevention of the increase in level of hormones of cytokinin nature under pickling.

  3. Yolk hormones influence in ovo chemosensory learning, growth, and feeding behavior in domestic chicks.

    PubMed

    Bertin, Aline; Meurisse, Maryse; Arnould, Cécile; Leterrier, Christine; Constantin, Paul; Cornilleau, Fabien; Vaudin, Pascal; Burlot, Thierry; Delaveau, Joel; Rat, Christophe; Calandreau, Ludovic

    2016-03-01

    In this study, we assessed whether prenatal exposure to elevated yolk steroid hormones can influence in ovo chemosensory learning and the behavior of domestic chicks. We simulated a maternal environmental challenge by experimentally enhancing yolk progesterone, testosterone, and estradiol concentrations in hen eggs prior to incubation. The embryos from these hormones-treated eggs (HO) as well as sham embryos (O) that had received the vehicle-only were exposed to the odor of fish oil (menhaden) between embryonic Days 11 and 20. An additional group of control embryos (C) was not exposed to the odor. All chicks were tested following hatching for their feeding preferences between foods that were or were not odorized with the menhaden odor. In the 3-min choice tests, the behavior of O chicks differed significantly according to the type of food whereas C and HO chicks showed no preference between odorized and non-odorized food. Our result suggests weaker response in HO chicks. In addition, HO chicks showed impaired growth and reduced intake of an unfamiliar food on the 24-h time scale compared to controls. Our data suggest that embryonic exposure to increased yolk hormone levels can alter growth, chemosensory learning, and the development of feeding behaviors.

  4. Investigating probation strategies with juvenile offenders: the influence of officers' attitudes and youth characteristics.

    PubMed

    Schwalbe, Craig S; Maschi, Tina

    2009-10-01

    Probation officers are the focal point for most interventions with delinquent youths in the juvenile justice system. The present study examines probation strategies and interventions in a sample of 308 probation officers who completed the Probation Practices Assessment Survey (PPAS) in a web-based survey. The PPAS measures six probation approaches: deterrence, restorative justice, treatment, confrontation, counseling, and behavioral tactics. Structural equation models and latent class analyses showed that probation officers use multiple approaches with delinquent youths consistent with the balanced and restorative justice movement. Younger youths, high-risk youths, and youths with prior social service involvements are likely to receive more intensive interventions. The implications of these findings for improving probation practices with delinquent youth are discussed.

  5. Donor life stage influences juvenile American eel Anguilla rostrata attraction to conspecific chemical cues.

    PubMed

    Galbraith, H S; Blakeslee, C J; Schmucker, A K; Johnson, N S; Hansen, M J; Li, W

    2017-01-01

    The present study investigated the potential role of conspecific chemical cues in inland juvenile American eel Anguilla rostrata migrations by assessing glass eel and 1 year old elver affinities to elver washings, and elver affinity to adult yellow eel washings. In two-choice maze assays, glass eels were attracted to elver washings, but elvers were neither attracted to nor repulsed by multiple concentrations of elver washings or to yellow eel washings. These results suggest that A. rostrata responses to chemical cues may be life-stage dependent and that glass eels moving inland may use the odour of the previous year class as information to guide migration. The role of chemical cues and olfaction in eel migrations warrants further investigation as a potential restoration tool.

  6. Donor life stage influences juvenile American eel Anguilla rostrata attraction to conspecific chemical cues

    USGS Publications Warehouse

    Galbraith, Heather S.; Blakeslee, Carrie J.; Schmucker, Andrew K.; Johnson, Nicholas; Hansen, Michael J.; Li, Weiming

    2017-01-01

    The present study investigated the potential role of conspecific chemical cues in inland juvenile American eel Anguilla rostrata migrations by assessing glass eel and 1 year old elver affinities to elver washings, and elver affinity to adult yellow eel washings. In two-choice maze assays, glass eels were attracted to elver washings, but elvers were neither attracted to nor repulsed by multiple concentrations of elver washings or to yellow eel washings. These results suggest that A. rostrata responses to chemical cues may be life-stage dependent and that glass eels moving inland may use the odour of the previous year class as information to guide migration. The role of chemical cues and olfaction in eel migrations warrants further investigation as a potential restoration tool.

  7. Influence of physico-chemical properties on the abundance of a few economically important juvenile fin-fishes of Vellar estuary.

    PubMed

    Brinda, S; Bragadeeswaran, S

    2005-01-01

    Studies on the economically important juvenile fin-fishes such as Elops machnata, Chanos chanos, Lates calcarifer, Epinephelus sp., Sillago sihama, Etroplus suratensis, Mugil cephalus, Liza parsia and Liza tade with relation to the hydrographical parameters as rainfall, temperature, salinity, dissolved oxygen and pH of Vellar estuary during September 2001 to August 2002. The simple correlation co-efficient showed positive significance against juvenile density with water temperature and dissolved oxygen. The influence of hydrographical parameters to the fin-fishes and its abundance is discussed.

  8. Understanding the influence of predation by introduced fishes on juvenile salmonids in the Columbia River Basin: Closing some knowledge gaps. Interim Report of Research 2010

    USGS Publications Warehouse

    Rose, Brien P.; Hansen, Gabriel S.; Mesa, Matthew G.

    2011-01-01

    In response to these recent concerns about the potential predatory impact of non-native piscivores on salmon survival, the Bonneville Power Administration (BPA) and the Columbia Basin Fish and Wildlife Authority (CBFWA) co-hosted a workshop to address predation on juvenile salmonids in the CRB by non-native fish (Halton 2008). The purpose of the workshop was to review, evaluate, and develop strategies to reduce predation by non-native fishes on juvenile salmonids. In the end, discussion at the workshop and at subsequent meetings considered two potential ideas to reduce predation by non-native fish on juvenile salmonids; (1) understanding the role of juvenile American shad Alosa sapidissima in the diet of non-native predators in the fall; and (2) the effects of localized, intense reductions of smallmouth bass in areas of particularly high salmonid predation. In this report, we describe initial efforts to understand the influence of juvenile American shad as a prey item for introduced predators in the middle Columbia River. Our first objective, addressed in Chapter 1, was to evaluate the efficacy of nonlethal methods to describe the physiological condition of smallmouth bass, walleye, and channel catfish from late summer through late fall. Such information will be used to understand the contribution of juvenile American shad to the energy reserves of predaceous fish prior to winter. In Chapter 2, we describe the results of some limited sampling to document the food habits of smallmouth bass, walleye, and channel catfish in three reservoirs of the middle Columbia River during late fall. Collectively, we hope to increase our understanding of the contribution of juvenile American shad to the diets of introduced predators and the contribution of this diet to their energy reserves, growth, and perhaps over-winter survival. Managers should be able to use this information for deciding whether to control the population of American shad in the CRB or for managing introduced

  9. Social influences on the acquisition of sex-typical foraging patterns by juveniles in a group of wild tufted capuchin monkeys (Cebus nigritus).

    PubMed

    Agostini, Ilaria; Visalberghi, Elisabetta

    2005-04-01

    Foraging traditions in primates are becoming the subject of increasing debate. Recent evidence for such a phenomenon was recently provided for wild Cebus capucinus [Fragaszy & Perry, 2003]. To better understand the bases of animal traditions, one should examine intrapopulation behavioral variability and the influence of social context on within-group transmission of specific foraging patterns. We studied the variability of foraging patterns across age and sex classes, and the proximity patterns of juveniles to adults of both sexes in a group of wild tufted capuchin monkeys (Cebus nigritus) living in the Iguazu National Park, Argentina. Foraging activity was examined for a period of 9 months in terms of proportions of focal samples devoted to foraging on certain food targets, microhabitats, and supports, and using specific foraging patterns. Proximity analyses were performed to reveal patterns of association between juveniles and adults. Sex differences in foraging behavior were present and overrode age differences. Overall, males ate more animal foods, foraged more for invertebrates on woody microhabitats (especially large branches), palms, and epiphytes, and used lower and larger supports than females. Females ate more fruits, foraged more on leaves and bamboo microhabitats, and used smaller supports than males. Juveniles were similar to adults of the same sex in terms of food targets, foraging substrates, and choice of supports, but were less efficient than adults. Proximity patterns indicated that juvenile males stayed in close spatial association with adult males and preferentially focused their "food interest" on them. This phenomenon was less evident in juvenile females. The degree to which juveniles, especially males, showed some of the sex-typical foraging patterns correlated positively with their proximity to adults of the same sex. These findings suggest that the acquisition of foraging behaviors by juvenile males is socially biased by their closeness to

  10. Hormonal effects on women's facial masculinity preferences: the influence of pregnancy, post-partum, and hormonal contraceptive use.

    PubMed

    Cobey, Kelly D; Little, Anthony C; Roberts, S Craig

    2015-01-01

    Here, we investigate changes in women's facial masculinity preferences across pregnancy and the post-partum period. The majority of previous research demonstrating changes in women's masculinity preferences has examined the impact of hormonal variation across the female menstrual cycle. Hormonal changes experienced during pregnancy and the post-partum period, critical periods in women's reproductive life histories, are considerably more extreme than the variation that occurs across the menstrual cycle, suggesting that differences in preferences may also be displayed during these times. We find that women's preference for masculinity in men's faces, but not women's faces, decreases in the post-partum period relative to pregnancy. Furthermore, when compared to a sample of nulliparous control participants, post-partum participants showed different masculinity preferences compared with women who were using hormonal contraception, with the direction of this difference dependent upon the sex of the face assessed. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Influence of Acidification on the Partitioning of Steroid Hormones among Filtrate, Filter Media, and Retained Particulate Matter.

    PubMed

    Havens, Sonya M; Hedman, Curtis J; Hemming, Jocelyn D C; Mieritz, Mark G; Shafer, Martin M; Schauer, James J

    2016-09-01

    Hormone contamination of aquatic systems has been shown to have deleterious effects on aquatic biota. However, the assessment of hormone contamination of aquatic environments requires a quantitative evaluation of the potential effects of sample preservation on hormone concentrations. This study investigated the influence of acidification (pH 2) of surface water samples on the partitioning of hormones among filtrate, filter media, and filter-retained particulate matter. Hormones were spiked into unpreserved and sulfuric acid-preserved ultrapure water and surface water runoff samples. The samples were filtered, and hormones were extracted from the filter and filtrate and analyzed by high-performance liquid chromatography. Acidification did not influence the partitioning of hormones onto the filter media. For the majority of the hormones investigated in this study, the partitioning of hormones to the filter-retained particulate matter was not influenced by acidification. Acidification increased the partitioning of progesterone and melengestrol acetate onto the retained particulate matter (about 25% for both analytes). Incorporation of an isotopically labeled internal standard (ISTD) for progesterone accounted for the loss of progesterone to the filter-retained particulates and resulted in accurate concentrations of progesterone in the filtrate. The incorporation of an ISTD for melengestrol acetate, however, was unable to account for the loss of melengestrol acetate to the retained particulates and resulted in underestimations of melengestrol acetate in the filtrate. Our results indicate that the analysis of melengestrol acetate in acid preserved surface runoff samples should be conducted on the filter-retained particulates as well as the filtrate.

  12. Influence of methionine oxidation on the aggregation of recombinant human growth hormone.

    PubMed

    Mulinacci, Filippo; Poirier, Emilie; Capelle, Martinus A H; Gurny, Robert; Arvinte, Tudor

    2013-09-01

    Oxidation of methionine (Met) residues is one of the major chemical degradations of therapeutic proteins. This chemical degradation can occur at various stages during production and storage of a biotherapeutic drug. During the oxidation process, the side chain of methionine residue undergoes a chemical modification, with the thioether group substituted by a sulfoxide group. In previous papers, we showed that oxidation of the two most accessible methionine residues of recombinant human growth hormone (r-hGH), Met¹⁴ and Met¹²⁵, has no influence on the conformation of the protein [1]. However, the oxidized r-hGH is less thermally stable than the native protein [2]. In the current work, the consequences of the oxidation of these two methionine residues on the aggregation of r-hGH were investigated. The aggregation properties and kinetics of the native and oxidized r-hGH were measured in different buffers with both spectroscopic and chromatographic methods. Stabilities of oxidized and non-oxidized r-hGH were studied after storage at 37°C and freeze/thawing cycles. Methionine oxidation influenced the aggregation properties of r-hGH. In accelerated stability studies at 37°C, oxidized hormone aggregated more and faster than non-oxidized hormone. In freezing/thawing stability studies, it was found that oxidized r-hGH was less stable than its non-oxidized counterpart. In case of hGH, we have shown that chemical degradations such as oxidation can affect its physical stability and can induce aggregation.

  13. Sleep, rhythms, and the endocrine brain: influence of sex and gonadal hormones.

    PubMed

    Mong, Jessica A; Baker, Fiona C; Mahoney, Megan M; Paul, Ketema N; Schwartz, Michael D; Semba, Kazue; Silver, Rae

    2011-11-09

    While much is known about the mechanisms that underlie sleep and circadian rhythms, the investigation into sex differences and gonadal steroid modulation of sleep and biological rhythms is in its infancy. There is a growing recognition of sex disparities in sleep and rhythm disorders. Understanding how neuroendocrine mediators and sex differences influence sleep and biological rhythms is central to advancing our understanding of sleep-related disorders. While it is known that ovarian steroids affect circadian rhythms in rodents, the role of androgen is less understood. Surprising findings that androgens, acting via androgen receptors in the master "circadian clock" within the suprachiasmatic nucleus, modulate photic effects on activity in males point to novel mechanisms of circadian control. Work in aromatase-deficient mice suggests that some sex differences in photic responsiveness are independent of gonadal hormone effects during development. In parallel, aspects of sex differences in sleep are also reported to be independent of gonadal steroids and may involve sex chromosome complement. This a summary of recent work illustrating how sex differences and gonadal hormones influence sleep and circadian rhythms that was presented at a Mini-Symposium at the 2011 annual meeting of the Society for Neuroscience.

  14. Influence of metabolic hormones and nutrition on ovarian follicle development in cattle: practical implications.

    PubMed

    Gong, J G

    2002-07-01

    Nutrition has long been known to have a profound influence on reproductive performance of female cattle, but the underlying mechanism remains poorly understood. Whilst early investigations focused on the modulation of nutrition on hypothalamic-pituitary axis, more recent studies have tested the hypothesis that metabolic hormones as nutritional signals exert a direct effect at the ovarian level. In cattle, treatment with recombinant bovine somatotrophin (rGH) significantly increases the population of small ovarian follicles. This is associated with increases in circulating concentrations of insulin and insulin-like growth factor-I (IGF-I). Subsequent studies, both in vitro and in vivo, have highlighted the importance of IGF-I and/or insulin acting in synergy with FSH and LH. More recently, we demonstrated that feeding heifers with 200% maintenance requirements for a short period significantly increases circulating insulin concentrations and population of small ovarian follicles. Based on these findings, our recent work has aimed at addressing some practical problems in cattle production. Firstly, we showed that both rGH pretreatment and increased dietary intake significantly enhance the response to standard superovulatory regimes. Secondly, we have demonstrated that feeding a diet to increase circulating insulin concentrations during the early lactation can advance the first ovulation postpartum and increase conception rate to the first service in dairy cows. In summary, nutrition influences ovarian follicle development in cattle possibly through changes in metabolic hormones. These interactions can be manipulated to improve reproductive performance.

  15. Mechanical, hormonal and metabolic influences on blood vessels, blood flow and bone.

    PubMed

    Prisby, Rhonda D

    2017-12-01

    Bone tissue is highly vascularized due to the various roles bone blood vessels play in bone and bone marrow function. For example, the vascular system is critical for bone development, maintenance and repair and provides O2, nutrients, waste elimination, systemic hormones and precursor cells for bone remodeling. Further, bone blood vessels serve as egress and ingress routes for blood and immune cells to and from the bone marrow. It is becoming increasingly clear that the vascular and skeletal systems are intimately linked in metabolic regulation and physiological and pathological processes. This review examines how agents such as mechanical loading, parathyroid hormone, estrogen, vitamin D and calcitonin, all considered anabolic for bone, have tremendous impacts on the bone vasculature. In fact, these agents influence bone blood vessels prior to influencing bone. Further, data reveal strong associations between vasodilator capacity of bone blood vessels and trabecular bone volume, and poor associations between estrogen status and uterine mass and trabecular bone volume. Additionally, this review highlights the importance of the bone microcirculation, particularly the vascular endothelium and NO-mediated signaling, in the regulation of bone blood flow, bone interstitial fluid flow and pressure and the paracrine signaling of bone cells. Finally, the vascular endothelium as a mediator of bone health and disease is considered. © 2017 Society for Endocrinology.

  16. Sleep, Rhythms, and the Endocrine Brain: Influence of Sex and Gonadal Hormones

    PubMed Central

    Mong, Jessica A.; Baker, Fiona C.; Mahoney, Megan M.; Paul, Ketema N.; Schwartz, Michael D.; Semba, Kazue; Silver, Rae

    2011-01-01

    While much is known about the mechanisms that underlie sleep and circadian rhythms, the investigation into sex differences and gonadal steroid modulation of sleep and biological rhythms is in its infancy. There is a growing recognition of sex disparities in sleep and rhythm disorders. Understanding how neuroendocrine mediators and sex differences influence sleep and biological rhythms is central to advancing our understanding of sleep-related disorders. While it is known that ovarian steroids affect circadian rhythms in rodents, the role of androgen is less understood. Surprising findings that androgens, acting via androgen receptors in the master “circadian clock” within the suprachiasmatic nucleus (SCN), modulate photic effects on activity in males points to novel mechanisms of circadian control. Work in aromatase deficient (ArKO) mice suggests that some sex differences in photic responsiveness are independent of gonadal hormone effects during development. In parallel, aspects of sex differences in sleep are also reported to be independent of gonadal steroids and may involve sex chromosome complement. This a summary of recent work illustrating how sex differences and gonadal hormones influence sleep and circadian rhythms that was presented at a mini-symposium at the 2011 annual meeting of the Society for Neuroscience. PMID:22072663

  17. Metabolism of testosterone by human granulosa cells in culture: influence of follicle-stimulating hormone and luteinizing hormone

    SciTech Connect

    Moon, Y.S.; Duleba, A.; Leung, P.C.; Gomel, V.

    1982-03-15

    Human granulosa cells were isolated from follicles (8 to 15 mm) and cultivated for 24 hours in the presence or absence of follicle-stimulating hormone (NIH-FSH-HS-1, 1 microgram/ml) and luteinizing hormone (NIAMDD-hLH-1, 1 microgram/ml). Testosterone -4-14C was added subsequently to all cultures for 4-, 6-, and 24-hour periods. Of the seven metabolites of testosterone studied, 17 beta-estradiol (E2) and estrone (E1) were the major products. In all patients, levels of E2 were three to ten times higher than those of E1. Production of E2, but not E1, was stimulated by either follicle-stimulating hormone (FSH) or luteinizing hormone (LH). The cells of the largest follicle (15 mm) showed greater response to LH than to FSH. Production of the other C19 and C18 metabolites was very low or negligible. These results further suggest that FSH regulates the aromatization of testosterone in human granulosa cells, and that LH may have the same effect on the matured follicle during the preovulatory period.

  18. Influence of infection with Renibacterium salmoninarum on susceptibility of juvenile spring chinook salmon to gas bubble trauma

    USGS Publications Warehouse

    Weiland, L.K.; Mesa, M.G.; Maule, A.G.

    1999-01-01

    During experiments in our laboratory to assess the progression and severity of gas bubble trauma (GBT) in juvenile spring chinook salmon Oncorhynchus tshawytscha, we had the opportunity to assess the influence of Renibacterium salmoninarum (Rs), the causative agent of bacterial kidney disease, on the susceptibility of salmon to GBT. We exposed fish with an established infection of Rs to 120% total dissolved gas (TDG) for 96 h and monitored severity of GBT signs in the fins and gills, Rs infection level in kidneys by using an enzyme-linked immunosorbent assay (ELISA), and mortality. Mortality occurred rapidly after exposure to 120% TDG, with a LT20 (time necessary to kill 20% of the population) of about 37 h, which is at a minimum about 16% earlier than other bioassays we have conducted using fish that had no apparent signs of disease. Fish that died early (from 31 to 36 h and from 49 to 52 h) had significantly higher infection levels (mean ?? SE ELISA absorbance = 1.532 ?? 0.108) than fish that survived for 96h (mean ?? SE ELISA absorbance = 0.828 ?? 0.137). Fish that died early also had a significantly greater number of gill filaments occluded with bubbles than those that survived 96 h. Conversely, fish that survived for 96 h had a significantly higher median fin severity ranking than those that died early. Our results indicate that fish with moderate to high levels of Rs infection are more vulnerable to the effects of dissolved gas supersaturation (DGS) and die sooner than fish with lower levels of Rs infection. However, there is a substantial amount of individual variation in susceptibility to the apparent cumulative effects of DGS and Rs infection. Collectively, our findings have important implications to programs designed to monitor the prevalence and severity of GBT in juvenile salmonids in areas like the Columbia River basin and perhaps elsewhere.

  19. The influence of ethanol and liver disease on sex hormones and hepatic oestrogen receptors in women.

    PubMed

    Becker, U

    1993-09-01

    In contrast to the numerous studies of men, very few studies have been concerned with sex hormone disturbances in women with chronic alcoholic and non-alcoholic liver diseases. The aim of the study was, to evaluate the effect of ethanol and liver dysfunction on menstrual cycle, serum sex hormone concentrations and hepatic oestrogen receptors in women. In premenopausal female alcoholics ethanol consumption increase the frequency of menstrual disturbances, abortions, and miscarriages, while infertility is not frequent. Acute ethanol intoxication has only minor effects on pituitary-gonadal hormones in premenopausal women, while chronic ethanol abuse lead to reduced concentrations of sulphated steroids, and these changes may be seen before severe liver dysfunction has appeared. In women liver dysfunction lead to earlier occurrence of menopause in comparison with normal controls, while information is insufficient or lacking regarding the influence upon fertility, pregnancy outcome and sexual behavior in women. In postmenopausal women with alcoholic and non-alcoholic liver disease, the main disturbances of sex hormone metabolism consist of elevated oestrone and sex hormone binding globulin (SHBG) concentrations, while serum concentrations of steroid sulphates and 5 alpha-dihydrotestosterone (DHT) are reduced, and the degree of liver dysfunction is a major determinant for the observed disturbances. The presence of high affinity, low capacity, specific oestrogen receptors (ER) in the liver is confirmed using a ligand binding assay (DCC), specificity analyses, and sucrose gradient centrifugation. Furthermore, the sensitivity of an enzyme immunoassay has been improved enabling the quantitative measurement of hepatic ER in 102 small liver biopsies from patients with alcoholic and non-alcoholic liver diseases. The method is suitable for quantitative assessment and ER in small tissue samples, and can be applied to other tissues than the liver. Patients with chronic liver

  20. Influence of etanercept on leptin and ghrelin secretion in children with juvenile idiopathic arthritis.

    PubMed

    Maciejewska-Paszek, Izabela; Grochowska-Niedworok, Elżbieta; Siwiec, Andrzej; Gruenpeter, Anna; Dul, Lechosław; Irzyniec, Tomasz

    2017-04-01

    Objective To assess possible changes in leptin and ghrelin secretion due to etanercept in juvenile idiopathic arthritis (JIA). Methods 50 patients with JIA and 16 age-matched controls were enrolled into this prospective, cross-sectional study. Serum leptin, total and acyl ghrelin were measured in addition to white blood cell (WBC) and lymphocyte counts. Results 25 patients received etanercept and 25 conventional therapies (including methotrexate) for JIA. There was no difference between treatment and control groups in leptin or ghrelin levels and no evidence of a relationship between leptin and ghrelin in patients with JIA. In all children with JIA there was a correlation between leptin and body mass index (BMI). However, compared with children in the conventional treatment group, children in the etanercept group showed a positive correlation between total ghrelin and BMI and those with a low BMI showed a negative correlation between acyl ghrelin and BMI. Conclusion No differences in leptin and ghrelin concentrations were found when patients with JIA and controls were compared or when patients who received etanercept were compared with those who received conventional treatment for JIA.

  1. Influence of thermal challenge on conditioned feeding forays of juvenile rainbow trout

    SciTech Connect

    Munson, B.H.; McCormick, J.H.; Collins, H.L.

    1980-01-01

    Juvenile rainbow trout (Salmo gairdneri) conditioned to traverse a 2.4-m-long channel to receive a food reward were subjected to in-transit thermal challenges. Conditioning was to a criterion that required 80% of the fish to leave the home area and reach the reward area within 2 minutes of release. Challenges were at successive 3 C increments above acclimation or the previous challenge temperature. Fish were first observed to delay their entrance into the intervening heated water at challenge temperatures of 12 to 15 C above acclimation. At each increment above 12 to 15 C over acclimation temperature, delay in transit increased; however, complete group inhibition was never achieved. Above their critical thermal maximum (CTM) the reward was achieved even at the expense of deaths among the achievers. Responses were the same whether fish were challenged individually or as groups. Fish exposed to their CTM without prior challenges at less stressful temperatures responded similarly to those receiving progressively greater challenges.

  2. Environmental Influences on the Spatial Ecology of Juvenile Smalltooth Sawfish (Pristis pectinata): Results from Acoustic Monitoring

    PubMed Central

    Simpfendorfer, Colin A.; Yeiser, Beau G.; Wiley, Tonya R.; Poulakis, Gregg R.; Stevens, Philip W.; Heupel, Michelle R.

    2011-01-01

    To aid recovery efforts of smalltooth sawfish (Pristis pectinata) populations in U.S. waters a research project was developed to assess how changes in environmental conditions within estuarine areas affected the presence, movements, and activity space of this endangered species. Forty juvenile P. pectinata were fitted with acoustic tags and monitored within the lower 27 km of the Caloosahatchee River estuary, Florida, between 2005 and 2007. Sawfish were monitored within the study site from 1 to 473 days, and the number of consecutive days present ranged from 1 to 125. Residency index values for individuals varied considerably, with annual means highest in 2005 (0.95) and lowest in 2007 (0.73) when several P. pectinata moved upriver beyond detection range during drier conditions. Mean daily activity space was 1.42 km of river distance. The distance between 30-minute centers of activity was typically <0.1 km, suggesting limited movement over short time scales. Salinity electivity analysis demonstrated an affinity for salinities between 18 and at least 24 psu, suggesting movements are likely made in part, to remain within this range. Thus, freshwater flow from Lake Okeechobee (and its effect on salinity) affects the location of individuals within the estuary, although it remains unclear whether or not these movements are threatening recovery. PMID:21347294

  3. Environmental influences on the spatial ecology of juvenile smalltooth sawfish (Pristis pectinata): results from acoustic monitoring.

    PubMed

    Simpfendorfer, Colin A; Yeiser, Beau G; Wiley, Tonya R; Poulakis, Gregg R; Stevens, Philip W; Heupel, Michelle R

    2011-02-11

    To aid recovery efforts of smalltooth sawfish (Pristis pectinata) populations in U.S. waters a research project was developed to assess how changes in environmental conditions within estuarine areas affected the presence, movements, and activity space of this endangered species. Forty juvenile P. pectinata were fitted with acoustic tags and monitored within the lower 27 km of the Caloosahatchee River estuary, Florida, between 2005 and 2007. Sawfish were monitored within the study site from 1 to 473 days, and the number of consecutive days present ranged from 1 to 125. Residency index values for individuals varied considerably, with annual means highest in 2005 (0.95) and lowest in 2007 (0.73) when several P. pectinata moved upriver beyond detection range during drier conditions. Mean daily activity space was 1.42 km of river distance. The distance between 30-minute centers of activity was typically <0.1 km, suggesting limited movement over short time scales. Salinity electivity analysis demonstrated an affinity for salinities between 18 and at least 24 psu, suggesting movements are likely made in part, to remain within this range. Thus, freshwater flow from Lake Okeechobee (and its effect on salinity) affects the location of individuals within the estuary, although it remains unclear whether or not these movements are threatening recovery.

  4. The influence of juvenile wood content on shear parallel, compression,and tension perpendicular to grain strength and mode I fracture toughness of loblolly pine at various ring orientation

    Treesearch

    David E. Kretschmann

    2008-01-01

    Forest products from improved trees grown on managed plantations and harvested in short rotations will contain higher proportions of juvenile wood than in current harvests. More information is needed on the influence of juvenile wood on lumber properties. Most information developed to date has concentrated on ultimate tensile stress, modulus of rupture, and modulus of...

  5. Hormones and pheromones in regulation of insect behavior

    USDA-ARS?s Scientific Manuscript database

    Both pheromones and hormones are well recognized regulators of insect biology. However, the interactions between hormones and pheromones in coordinating insect biology are less well understood. We have studied the interactions between juvenile hormone, its precursor methyl farnesoate, and pheromon...

  6. Does resolution of flow field observation influence apparent habitat use and energy expenditure in juvenile coho salmon?

    USGS Publications Warehouse

    Tullos, Desiree D.; Walter, Cara; Dunham, Jason

    2016-01-01

    This study investigated how the resolution of observation influences interpretation of how fish, juvenile Coho Salmon (Oncorhynchus kisutch), exploit the hydraulic environment in streams. Our objectives were to evaluate how spatial resolution of the flow field observation influenced: (1) the velocities considered to be representative of habitat units; (2) patterns of use of the hydraulic environment by fish; and (3) estimates of energy expenditure. We addressed these objectives using observations within a 1:1 scale physical model of a full-channel log jam in an outdoor experimental stream. Velocities were measured with Acoustic Doppler Velocimetry at a 10 cm grid spacing, whereas fish locations and tailbeat frequencies were documented over time using underwater videogrammetry. Results highlighted that resolution of observation did impact perceived habitat use and energy expenditure, as did the location of measurement within habitat units and the use of averaging to summarize velocities within a habitat unit. In this experiment, the range of velocities and energy expenditure estimates increased with coarsening resolution (grid spacing from 10 to 100 cm), reducing the likelihood of measuring the velocities locally experienced by fish. In addition, the coarser resolutions contributed to fish appearing to select velocities that were higher than what was measured at finer resolutions. These findings indicate the need for careful attention to and communication of resolution of observation in investigating the hydraulic environment and in determining the habitat needs and bioenergetics of aquatic biota.

  7. Sleep patterns in male juvenile monkeys are influenced by gestational iron deprivation and monoamine oxidase A genotype.

    PubMed

    Golub, Mari S; Hogrefe, Casey E

    2014-11-14

    Individual differences in sleep patterns of children may have developmental origins. In the present study, two factors known to influence behavioural development, monoamine oxidase A (MAOA) genotype and prenatal Fe-deficient (ID) diet, were examined for their influences on sleep patterns in juvenile rhesus monkeys. Sleep patterns were assessed based on a threshold for inactivity as recorded by activity monitors. Pregnant monkeys were fed diets containing either 100 parts per million (ppm) Fe (Fe sufficient, IS) or 10 ppm Fe (ID). At 3-4 months of age, male offspring were genotyped for polymorphisms of the MAOA gene that lead to high or low transcription. At 1 and 2 years of age, sleep patterns were assessed. Several parameters of sleep architecture changed with age. At 1 year of age, monkeys with the low-MAOA genotype demonstrated a trend towards more sleep episodes at night compared with those with the high-MAOA genotype. When monkeys reached 2 years of age, prenatal ID reversed this trend; ID in the low-MAOA group resulted in sleep fragmentation, more awakenings at night and more sleep episodes during the day when compared with prenatal IS in this genotype. The ability to consolidate sleep during the dark cycle was disrupted by prenatal ID, specifically in monkeys with the low-MAOA genotype.

  8. How Doth the Little Crocodilian: Analyzing the Influence of Environmental Viscosity on Feeding Performance of Juvenile Alligator mississippiensis

    PubMed Central

    Kerfoot, James R.; Easter, Emily; Elsey, Ruth M.

    2016-01-01

    Wetland habitats are used as nursery sites for hatchling and juvenile alligators (Alligator mississippiensis), where they utilize prey from aquatic and terrestrial settings. However, little is known about how viscosity of the medium influences feeding performance. We hypothesized that timing and linear excursion feeding kinematic variables would be different for individuals feeding on prey above the water compared with the same individuals feeding underwater. Individuals were fed immobile fish prey and feeding events were recorded using a high speed video camera. Feeding performance was summarized by analyzing three feeding kinematic variables (maximum gape, maximum gape velocity, duration of feeding bout) and success of strike. Results of a series of paired t-tests indicated no significant difference in kinematic variables between feeding events above water compared with underwater. Similarity in feeding performance could indicate that prey-capture is not altered by environmental viscosity or that feeding behavior can mitigate its influence. Behavioral differences were observed during feeding events with alligators approaching underwater prey having their mouths partially opened versus fully closed when feeding above water. This behavior could be an indication of a strategy used to overcome water viscosity. PMID:27706023

  9. How Doth the Little Crocodilian: Analyzing the Influence of Environmental Viscosity on Feeding Performance of Juvenile Alligator mississippiensis.

    PubMed

    Kerfoot, James R; Easter, Emily; Elsey, Ruth M

    2016-09-30

    Wetland habitats are used as nursery sites for hatchling and juvenile alligators (Alligator mississippiensis), where they utilize prey from aquatic and terrestrial settings. However, little is known about how viscosity of the medium influences feeding performance. We hypothesized that timing and linear excursion feeding kinematic variables would be different for individuals feeding on prey above the water compared with the same individuals feeding underwater. Individuals were fed immobile fish prey and feeding events were recorded using a high speed video camera. Feeding performance was summarized by analyzing three feeding kinematic variables (maximum gape, maximum gape velocity, duration of feeding bout) and success of strike. Results of a series of paired t-tests indicated no significant difference in kinematic variables between feeding events above water compared with underwater. Similarity in feeding performance could indicate that prey-capture is not altered by environmental viscosity or that feeding behavior can mitigate its influence. Behavioral differences were observed during feeding events with alligators approaching underwater prey having their mouths partially opened versus fully closed when feeding above water. This behavior could be an indication of a strategy used to overcome water viscosity.

  10. Short-term exposure to municipal wastewater influences energy, growth, and swimming performance in juvenile Empire Gudgeons (Hypseleotris compressa).

    PubMed

    Melvin, Steven D

    2016-01-01

    Effectively treating domestic wastewater is paramount for preserving the health of aquatic ecosystems. Various technologies exist for wastewater treatment, ranging from simple pond-based systems to advanced filtration, and it is important to evaluate the potential for these different options to produce water that is acceptable for discharge. Sub-lethal responses were therefore assessed in juvenile Empire Gudgeons (Hypseleotris compressa) exposed for a period of two weeks to control, 12.5, 25, 50, and 100% wastewater treated through a multi-stage constructed wetland (CW) treatment system. Effects on basic energy reserves (i.e., lipids and protein), growth and condition, and swimming performance were quantified following exposure. A significant increase in weight and condition was observed in fish exposed to 50 and 100% wastewater dilutions, whereas whole-body lipid content was significantly reduced in these treatments. Maximum swimming velocity increased in a dose-dependent manner amongst treatment groups (although not significantly), whereas angular velocity was significantly reduced in the 50 and 100% dilutions. Results demonstrate that treated domestic wastewater can influence the growth and swimming performance of fish, and that such effects may be related to alterations to primary energy stores. However, studies assessing complex wastewaters present difficulties when it comes to interpreting responses, as many possible factors can contribute towards the observed effects. Future research should address these uncertainties by exploring interaction between nutrients, basic water quality characteristics and relevant contaminant mixtures, for influencing the energetics, growth, and functional performance of aquatic animals.

  11. Does resolution of flow field observation influence apparent habitat use and energy expenditure in juvenile coho salmon?

    NASA Astrophysics Data System (ADS)

    Tullos, Desirée.; Walter, Cara; Dunham, Jason

    2016-08-01

    This study investigated how the resolution of observation influences interpretation of how fish, juvenile Coho Salmon (Oncorhynchus kisutch), exploit the hydraulic environment in streams. Our objectives were to evaluate how spatial resolution of the flow field observation influenced: (1) the velocities considered to be representative of habitat units; (2) patterns of use of the hydraulic environment by fish; and (3) estimates of energy expenditure. We addressed these objectives using observations within a 1:1 scale physical model of a full-channel log jam in an outdoor experimental stream. Velocities were measured with Acoustic Doppler Velocimetry at a 10 cm grid spacing, whereas fish locations and tailbeat frequencies were documented over time using underwater videogrammetry. Results highlighted that resolution of observation did impact perceived habitat use and energy expenditure, as did the location of measurement within habitat units and the use of averaging to summarize velocities within a habitat unit. In this experiment, the range of velocities and energy expenditure estimates increased with coarsening resolution (grid spacing from 10 to 100 cm), reducing the likelihood of measuring the velocities locally experienced by fish. In addition, the coarser resolutions contributed to fish appearing to select velocities that were higher than what was measured at finer resolutions. These findings indicate the need for careful attention to and communication of resolution of observation in investigating the hydraulic environment and in determining the habitat needs and bioenergetics of aquatic biota.

  12. Does resolution of flow field observation influence apparent habitat use and energy expenditure in juvenile coho salmon?

    NASA Astrophysics Data System (ADS)

    Tullos, D. D.; Walter, C.; Dunham, J.

    2016-12-01

    This study investigated how the resolution of observation influences interpretation of how fish, juvenile Coho Salmon (Oncorhynchus kisutch), exploit the hydraulic environment in streams. Our objectives were to evaluate how spatial resolution of the flow field observation influenced: 1) the velocities considered to be representative of habitat units; 2) patterns of use of the hydraulic environment by fish; and 3) estimates of energy expenditure. We addressed these objectives using observations within a 1:1 scale physical model of a full-channel log jam in an outdoor experimental stream. Velocities were measured with Acoustic Doppler Velocimetry at a 10 cm grid spacing, whereas fish locations and tailbeat frequencies were documented over time using underwater videogrammetry. Results highlighted that resolution of observation did impact perceived habitat use and energy expenditure, as did the location of measurement within habitat units and the use of averaging to summarize velocities within a habitat unit. In this experiment, the range of velocities and energy expenditure estimates increased with coarsening resolution, reducing the likelihood of measuring the velocities locally experienced by fish. In addition, the coarser resolutions contributed to fish appearing to select velocities that were higher than what was measured at finer resolutions. These findings indicate the need for careful attention to and communication of resolution of observation in investigating the hydraulic environment and in determining the habitat needs and bioenergetics of aquatic biota.

  13. Factors influencing the survival of outmigrating juvenile salmonids through multiple dam passages: an individual-based approach.

    PubMed

    Elder, Timothy; Woodley, Christa M; Weiland, Mark A; Strecker, Angela L

    2016-08-01

    Substantial declines of Pacific salmon populations have occurred over the past several decades related to large-scale anthropogenic and climatic changes in freshwater and marine environments. In the Columbia River Basin, migrating juvenile salmonids may pass as many as eight large-scale hydropower projects before reaching the ocean; however, the cumulative effects of multiple dam passages are largely unknown. Using acoustic transmitters and an extensive system of hydrophone arrays in the Lower Columbia River, we calculated the survival of yearling Chinook salmon (Oncorhynchus tshawytscha) and steelhead (O. mykiss) passing one, two, or three dams. We applied a unique index of biological characteristics and environmental exposures, experienced by each fish individually as it migrated downstream, in order to examine which factors most influence salmonid survival. High outflow volumes led to involuntary spill in 2011 and created an environment of supersaturated dissolved gas concentrations. In this environment, migrating smolt survival was strongly influenced by barometric pressure, fish velocity, and water temperature. The effect of these variables on survival was compounded by multiple dam passages compared to fish passing a single dam. Despite spatial isolation between dams in the Lower Columbia River hydrosystem, migrating smolt appear to experience cumulative effects akin to a press disturbance. In general, Chinook salmon and steelhead respond similarly in terms of survival rates and responses to altered environmental conditions. Management actions that limit dissolved gas concentrations in years of high flow will benefit migrating salmonids at this life stage.

  14. Influence of family environment on long-term psychosocial functioning of adolescents with juvenile fibromyalgia.

    PubMed

    Sil, Soumitri; Lynch-Jordan, Anne; Ting, Tracy V; Peugh, James; Noll, Jennie; Kashikar-Zuck, Susmita

    2013-06-01

    Little is known about the impact of family environment on the long-term adjustment of patients with juvenile-onset fibromyalgia (JFM). Our objective was to evaluate whether family environment in early adolescence predicted later physical functioning and depressive symptoms of adolescents with JFM as they transitioned to early adulthood in the context of a controlled long-term followup study. Participants consisted of 39 youth (mean age 18.7 years) with JFM and 38 healthy matched controls who completed web-based surveys about their health status (Short Form 36 health survey) and depressive symptoms (Beck Depression Inventory II) ~4 years after a home-based, in-person assessment of child and family functioning. During the initial assessment, parents of the participants (94% mothers) completed the Family Environment Scale and adolescents (mean age 14.8 years) completed self-report questionnaires about pain (visual analog scale) and depressive symptoms (Children's Depression Inventory). The results indicated that family environment during early adolescence significantly predicted greater depressive symptoms in early adulthood for both the JFM group and the healthy controls. In particular, a controlling family environment (use of rules to control the family and allowing little independence) during early adolescence was the driving factor in predicting poorer long-term emotional functioning for patients with JFM. Family environment did not significantly predict longer-term physical impairment for either group. Adolescents with JFM from controlling family environments are at an increased risk for poorer emotional functioning in early adulthood. Behavioral and family interventions should foster independent coping among adolescents with JFM and greater parenting flexibility to enhance successful long-term coping. Copyright © 2013 by the American College of Rheumatology.

  15. Influence of juvenile osteochondral conditions on racing performance in Thoroughbreds born in Normandy.

    PubMed

    Robert, Céline; Valette, Jean-Paul; Jacquet, Sandrine; Denoix, Jean-Marie

    2013-07-01

    The relationship between osteoarticular status and future athletic capacity is commonly accepted in equine practice, but there is little to support this belief in Thoroughbreds. The objective of this study was to assess the prevalence of juvenile osteochondral conditions (JOCC) in Thoroughbred yearlings and to investigate the significance of these with regard to subsequent racing performance. The radiographic files from 328 Thoroughbred yearlings born in Normandy were assessed in a consistent manner and entered into a database together with racing records. Logistic regression models were used to quantify the association between each radiographic parameter and racing performance (raced/not raced, placed/not placed, performer/not performer) at 2, 3, 4 and 5years of age. The front fetlock (30.2% of horses), the dorsal aspect of the hind fetlock (18%), the carpus (15.9%) and the distal part of the hock (15.5%) were the most commonly affected joints. Most horses (87.5%) raced either in turf flat races or in hurdle races. Starting a race at 2years old was more frequent for yearlings without radiographic findings (RF) on the carpus or with less than one RF of moderate severity. The proportions of horses placed at 3years old decreased with increasing number or severity of RF. In racing horses, there was no association between the presence of RF and earnings. The radiographic score, calculated as the sum of all the severity indices found on the radiographic file of the horse appeared well correlated with performance. Using this synthetic index might help veterinarians to evaluate radiographs of Thoroughbred yearlings for potential buyers.