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1.
Arch Insect Biochem Physiol ; 103(3): e21615, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31502704

RESUMO

Synthetic compounds that mimic the action of juvenile hormones (JHs) are founding members of a class of insecticides called insect growth regulators (IGRs). Like JHs, these juvenoids block metamorphosis of insect larvae to reproductive adults. Many biologically active juvenoids deviate in their chemical structure considerably from the sesquiterpenoid JHs, raising questions about the mode of action of such JH mimics. Despite the early deployment of juvenoid IGRs in the mid-1970s, their molecular effect could not be understood until recent discoveries of JH signaling through an intracellular JH receptor, namely the ligand-binding transcription factor Methoprene-tolerant (Met). Here, we briefly overview evidence defining three widely employed and chemically distinct juvenoid IGRs (methoprene, pyriproxyfen, and fenoxycarb), as agonist ligands of the JH receptor. We stress that knowledge of the target molecule is critical for using these compounds both as insecticides and as research tools.


Assuntos
Hormônios Juvenis/farmacologia , Metamorfose Biológica/efeitos dos fármacos , Animais , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Resistência a Inseticidas , Inseticidas/química , Inseticidas/metabolismo , Inseticidas/farmacologia , Hormônios Juvenis/agonistas , Hormônios Juvenis/química , Ligantes , Metoprene/metabolismo , Metoprene/farmacologia , Fenilcarbamatos/metabolismo , Fenilcarbamatos/farmacologia , Piridinas/metabolismo , Piridinas/farmacologia , Relação Estrutura-Atividade
2.
Parasitol Res ; 118(9): 2499-2507, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31363921

RESUMO

Stable flies (Stomoxys calcitrans Linnaeus, 1758) can have a considerable negative impact on animal well-being, health, and productivity. Since insecticides constitute the mainstay for their control, this study aimed at assessing the occurrence of insecticide resistance in S. calcitrans on dairy farms in Brandenburg, Germany. First, the susceptibility of stable flies from 40 dairy farms to a deltamethrin-impregnated fabric was evaluated using the FlyBox® field test method. Then, S. calcitrans strains from 10 farms were reared in the laboratory, and the offspring was tested against the adulticides deltamethrin and azamethiphos and the larvicides cyromazine and pyriproxyfen. The FlyBox® method indicated 100% resistance in stable flies against deltamethrin. Later, to the offspring of those 10 established laboratory strains previously caught on suspected dairy farms, these field findings could be confirmed with mortalities well below 90% 24 h following topical application of the calculated LD95 of deltamethrin and azamethiphos. The ten strains could therefore be classified as resistant to the tested insecticides. In contrast, exposure to the insect growth regulators cyromazine and pyriproxyfen at their recommended concentrations demonstrated 100% efficacy. Both larvicides inhibited the moulting process of the stable fly larval stages completely, showing that the stable fly strains tested were susceptible to them. The intensive use of insecticides in recent decades has probably promoted the development of insecticide resistance. Systematic surveys in different livestock production systems and vigilance are therefore deemed necessary for estimating the risk of insecticide resistance development on a nationwide scale.


Assuntos
Resistência a Inseticidas/fisiologia , Inseticidas/farmacologia , Hormônios Juvenis/farmacologia , Larva/efeitos dos fármacos , Muscidae/efeitos dos fármacos , Animais , Fazendas , Alemanha , Nitrilos/farmacologia , Organotiofosfatos/farmacologia , Piretrinas/farmacologia , Piridinas/farmacologia , Triazinas/farmacologia
3.
PLoS One ; 14(5): e0216800, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31107891

RESUMO

The reproductive ground plan hypothesis proposes that gene networks regulating foraging behavior and reproductive female physiology in social insects emerged from ancestral gene and endocrine factor networks. Expression of storage proteins such as vitellogenins and hexamerins is an example of this co-option. Hexamerins, through their role modulating juvenile hormone availability, are involved in caste determination in termites. The genome of the fire ant (Solenopsis invicta) encodes four hexamerin genes, hexamerin-like (LOC105192919, hereafter called hexamerin 1), hexamerin (LOC105204474, hereafter called hexamerin 2), arylphorin subunit alpha-like, and arylphorin subunit beta. In this study, a phylogenetic analysis of the S. invicta hexamerins determined that each predicted protein clustered with one of the orthologous Apis mellifera hexamerins. Gene expression analyses by RT-qPCR revealed differential expression of the hexamerins between queens and workers, and between specific task-allocated workers (nurses and foragers). Queens and nurses had significantly higher expression of all genes when compared to foragers. Hexamerin 1 was expressed at higher levels in queens, while hexamerin 2 and arylphorin subunit beta were expressed at significantly higher levels in nurses. Arylphorin subunit alpha-like showed no significant difference in expression between virgin queens and nurses. Additionally, we analyzed the relationship between the expression of hexamerin genes and S-hydroprene, a juvenile hormone analog. Significant changes in hexamerin expression were recorded in nurses, virgin queens, and foragers 12 h after application of the analog. Hexamerin 1 and arylphorin subunit alpha-like expression were significantly lower after analog application in virgin queens. In foragers, hexamerin 2 and arylphorin subunit beta were significantly lower after analog application, while in nurses expression of all genes were significantly lower after analog application. Our results suggest that in S. invicta hexamerin genes could be associated with reproductive division of labor and task-allocation of workers.


Assuntos
Formigas/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Proteínas de Insetos/biossíntese , Hormônios Juvenis/farmacologia , Vitelogeninas/biossíntese , Animais , Formigas/genética , Feminino , Proteínas de Insetos/genética , Vitelogeninas/genética
4.
Arch Insect Biochem Physiol ; 101(2): e21551, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30945779

RESUMO

The yellow protein of the takeout family (YPT) controls the development of yellow body color in the desert locust. This study focused on two aspects related to YPT in the locust. We first examined the expression pattern of YPT during nymphal stages because yellowing was not obvious during the early instars. YPT expression levels were extremely low in the second and third instars compared with the last two nymphal instars. Warm rearing temperature and juvenile hormone (JH) injection, which stimulated YPT expression in the late instars, had little effect in the second instar, suggesting that YPT expression during the early instars was suppressed and could not be stimulated by either of these factors. We also investigated delayed yellowing in fasting male adults, under the hypothesis that fasting decreased the JH titers and delayed the onset of YPT expression. Yellowing was delayed in fasting adults compared with well-fed adults and YPT expression was stimulated by JH injections at Day 15. However, we failed to obtain evidence that fasting significantly influenced the expression levels of YPT and the JH early-inducible gene Krüppel homolog 1 at Days 15 and 20 post-adult emergence. Results suggest that a YPT-independent mechanism possibly induces delayed yellowing in fasting males.


Assuntos
Gafanhotos/metabolismo , Proteínas de Insetos/metabolismo , Animais , Cor , Privação de Alimentos , Regulação da Expressão Gênica no Desenvolvimento , Gafanhotos/genética , Gafanhotos/crescimento & desenvolvimento , Proteínas de Insetos/genética , Hormônios Juvenis/farmacologia , Masculino , Ninfa/genética , Ninfa/crescimento & desenvolvimento , Ninfa/metabolismo
5.
Epidemiol Serv Saude ; 28(1): e2017316, 2019 02 18.
Artigo em Inglês, Português | MEDLINE | ID: mdl-30785572

RESUMO

OBJECTIVE: to evaluate, under simulated field conditions, the efficacy of pyriproxyfen (juvenile hormone), novaluron (chitin inhibitor) and spinosad (biolarvicide) in controlling Aedes aegypti. METHODS: periodic exposition of Ae. aegypti larvae collected in Itabuna, BA, Brazil, to recipients treated with larvicides and comparison of residual effect of treatment with the Rockefeller strain. RESULTS: the inhibitory effect on adult emergence after 60 days was spinosad 89.5%, novaluron 96.5% and pyriproxifen 75.4% for Itabuna larvae, with no statistical difference (p=0.412) between treatments; spinosad and novaluron had a higher percentage of mortality in the larval stage, 98.8% and 97.9% respectively; pyriproxyfen showed higher mortality (95.1%) in the pupal stage. CONCLUSION: the three larvicides demonstrated similar control; however, pyriprofyxen might give a false impression of breeding ground positivity as it acts at the pupal stage, compromising the indicators of infestation that are strategic parameters for control actions.


Assuntos
Inseticidas/farmacologia , Macrolídeos/farmacologia , Compostos de Fenilureia/farmacologia , Piridinas/farmacologia , Aedes/efeitos dos fármacos , Animais , Brasil , Combinação de Medicamentos , Hormônios Juvenis/farmacologia , Larva/efeitos dos fármacos , Controle de Mosquitos/métodos , Pupa/efeitos dos fármacos
6.
Arch Insect Biochem Physiol ; 101(1): e21540, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30793357

RESUMO

A highly conservative insulin signaling pathway, stable work of which is indicated by carbohydrates metabolism, is also known to play an important role in the control of stress resistance. Here we demonstrate that exposure to heat stress leads to a rise in the levels of trehalose and glucose in females of Drosophila melanogaster, but does not affect the expression level of the trehalase (Treh) gene. We have shown that the rise in juvenile hormone (JH) and dopamine decreases levels of both carbohydrates under the normal conditions but brings them to values close to normal following the stress exposure. The data obtained suggest that (a) dopamine and JH involved in the neuroendocrine stress reaction in D. melanogaster also take part in the regulation of carbohydrates metabolism, tending to normalize it after stress; (b) the regulation of trehalose content under stress does not occur at the level of transcription of the degrading enzyme.


Assuntos
Metabolismo dos Carboidratos/efeitos dos fármacos , Dopamina/metabolismo , Drosophila melanogaster/fisiologia , Hormônios Juvenis/farmacologia , Animais , Di-Hidroxifenilalanina/farmacologia , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/efeitos dos fármacos , Drosophila melanogaster/metabolismo , Feminino , Expressão Gênica , Resposta ao Choque Térmico/fisiologia , Insulina/metabolismo , Insulina/farmacologia , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Trealase/genética , Trealase/metabolismo , Trealose/metabolismo
7.
Gen Comp Endocrinol ; 274: 80-86, 2019 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-30654021

RESUMO

In vertebrates, titers of androgens such as testosterone are known to upregulate aggressive behaviors associated with reproduction. In insects, juvenile hormone (JH) is a good candidate for studying the flexibility of insect endocrine responses because it has important effects on both reproductive processes and behavior. JH has a gonadotropic effect across a broad range of insect species, increasing ovarian development in females, and may have a role in the regulation of aggressive behavior during competition. In Hymenoptera, the functions of JH have been studied in facultatively eusocial species such as polistine wasps, bumblebees, ants and bees. Surprisingly, no work has yet focused on the relationship between JH, reproduction and aggressiveness in a non-social Hymenoptera, although it may help to understand how JH actions have evolved across taxa with different degrees of sociality. Here, we explored how JH treatment influenced: i) female reproductive status, and ii) the intensity (aggressiveness) and resolution of conflict, in Eupelmus vuilleti (Hymenoptera: Eupelmidae), a solitary ectoparasitoid wasp in which females fight over hosts. We demonstrated that intra-abdominal injections of JH increased the number of mature eggs in females after 24 h. In addition, the number of aggressive behaviors displayed by females was affected by the interaction between JH treatment and the number of mature eggs in their abdomen, but mature egg load alone predicted the outcome of staged contests. Wasps were more aggressive when they had more ready-to-lay eggs, with this effect being stronger when females were injected with JH. Moreover, females won more frequently when they had higher mature egg load. Our results highlight how JH affects egg maturation and aggressive behaviors in Eupelmus vuilleti females. To our knowledge, this is the first study showing that hormone manipulation can modulate females' reproduction status and behavior during intraspecific competition over hosts in a non-social hymenopteran parasitoid.


Assuntos
Agressão/efeitos dos fármacos , Hormônios Juvenis/farmacologia , Comportamento Social , Vespas/fisiologia , Animais , Feminino , Óvulo/efeitos dos fármacos , Reprodução/efeitos dos fármacos , Testosterona
8.
Development ; 145(24)2018 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-30470705

RESUMO

Krüppel-homolog 1 (Kr-h1), a zinc-finger transcription factor, inhibits larval metamorphosis and promotes adult reproduction by transducing juvenile hormone (JH). Although the transcriptional regulation of Kr-h1 has been extensively studied, little is known about its regulation at the post-transcriptional level. Using the migratory locust Locusta migratoria as a model system, we report here that the microRNAs let-7 and miR-278 bound to the Kr-h1 coding sequence and downregulated its expression. Application of let-7 and miR-278 mimics (agomiRs) significantly reduced the level of Kr-h1 transcripts, resulting in partially precocious metamorphosis in nymphs as well as markedly decreased yolk protein precursors, arrested ovarian development and blocked oocyte maturation in adults. Moreover, the expression of let-7 and miR-278 was repressed by JH, constituting a regulatory loop of JH signaling. This study thus reveals a previously unknown regulatory mechanism whereby JH suppresses the expression of let-7 and miR-278, which, together with JH induction of Kr-h1 transcription, prevents the precocious metamorphosis of nymphs and stimulates the reproduction of adult females. These results advance our understanding of the coordination of JH and miRNA regulation in insect development.


Assuntos
Genes de Insetos , Gafanhotos/crescimento & desenvolvimento , Gafanhotos/genética , Hormônios Juvenis/farmacologia , Fatores de Transcrição Kruppel-Like/genética , Metamorfose Biológica/genética , MicroRNAs/metabolismo , Oogênese/genética , Animais , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Gafanhotos/efeitos dos fármacos , Fatores de Transcrição Kruppel-Like/metabolismo , Metamorfose Biológica/efeitos dos fármacos , MicroRNAs/genética , Oócitos/metabolismo , Oogênese/efeitos dos fármacos , Óvulo/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Fatores de Tempo , Vitelogênese/efeitos dos fármacos , Vitelogênese/genética
9.
Pestic Biochem Physiol ; 150: 27-32, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30195384

RESUMO

Insect growth regulators (IGRs) are attractive pest control agents due to their high target specificity and relative safety to the environment. Recently, plants have been shown to synthesize IGRs that affect the insect juvenile hormone (JH) as a part of their defense mechanisms. Using a yeast two-hybrid system transformed with the Aedes aegypti JH receptor as a reporter system, we identified several JH agonists (JHAs) and antagonists (JHANs) causing retardation in the ovarian development of female Asian tiger mosquito, Aedes albopictus, from plant essential oil compounds. While the JHAs increased the expression of a JH-induced gene, the JHANs caused a reduction in the expression of the same gene. The compounds identified in this study could provide insights into plant-insect interactions and may be useful for the development of novel IGR insecticides.


Assuntos
Aedes/efeitos dos fármacos , Hormônios Juvenis/farmacologia , Plantas/química , Receptores de Superfície Celular/metabolismo , Aedes/crescimento & desenvolvimento , Aedes/metabolismo , Animais , Feminino , Hormônios Juvenis/antagonistas & inibidores , Hormônios Juvenis/isolamento & purificação , Larva/crescimento & desenvolvimento , Óleos Voláteis/farmacologia
10.
Genetics ; 209(4): 1225-1234, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29934338

RESUMO

Sterile castes are a defining criterion of eusociality; investigating their evolutionary origins can critically advance theory. In termites, the soldier caste is regarded as the first acquired permanently sterile caste. Previous studies showed that juvenile hormone (JH) is the primary factor inducing soldier differentiation, and treatment of workers with artificial JH can generate presoldier differentiation. It follows that a shift from a typical hemimetabolous JH response might be required for soldier formation during the course of termite evolution within the cockroach clade. To address this possibility, analysis of the role of JH and its signaling pathway was performed in the termite Zootermopsis nevadensis and compared with the wood roach Cryptocercus punctulatus, a member of the sister group of termites. Treatment with a JH analog (JHA) induced a nymphal molt in C. punctulatus RNA interference (RNAi) of JH receptor Methoprene tolerant (Met) was then performed, and it inhibited the presoldier molt in Z. nevadensis and the nymphal molt in C. punctulatus Knockdown of Met in both species inhibited expression of 20-hydroxyecdysone (20E; the active form of ecdysone) synthesis genes. However, in Z. nevadensis, several 20E signaling genes were specifically inhibited by Met RNAi. Consequently, RNAi of these genes were performed in JHA-treated termite individuals. Knockdown of 20E signaling and nuclear receptor gene, Hormone receptor 39 (HR39/FTZ-F1ß) resulted in newly molted individuals with normal worker phenotypes. This is the first report of the JH-Met signaling feature in termites and Cryptocercus JH-dependent molting activation is shared by both taxa and mediation between JH receptor and 20E signalings for soldier morphogenesis is specific to termites.


Assuntos
Baratas/crescimento & desenvolvimento , Perfilação da Expressão Gênica/métodos , Proteínas de Insetos/genética , Isópteros/crescimento & desenvolvimento , Animais , Comportamento Animal/efeitos dos fármacos , Baratas/efeitos dos fármacos , Baratas/genética , Ecdisterona/metabolismo , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Redes Reguladoras de Genes/efeitos dos fármacos , Isópteros/efeitos dos fármacos , Isópteros/genética , Hormônios Juvenis/farmacologia , Muda/efeitos dos fármacos , Comportamento Social
11.
J Econ Entomol ; 111(3): 1388-1394, 2018 05 28.
Artigo em Inglês | MEDLINE | ID: mdl-29617840

RESUMO

The susceptibility status of Aedes albopictus (Skuse; Diptera: Culicidea) larvae collected from 13 districts in Sarawak state, Malaysia was evaluated against five insect growth regulators (IGRs) namely, methoprene, pyriproxyfen, diflubenzuron, cyromazine, and novaluron. Field populations of Ae. albopictus were susceptible to methoprene, pyriproxyfen, cyromazine and novaluron with resistance ratios (RRs) ranging from 0.19-0.38, 0.05-0.14, 0.50-0.95, and 0.75-1.00, respectively. Nevertheless, tolerance towards diflubenzuron (0.33-1.33) was observed in this study. In general, these IGRs exhibited promising results and can be used as alternative control agents against field populations of Ae. albopictus in Sarawak, Malaysia.


Assuntos
Aedes/efeitos dos fármacos , Controle de Insetos , Hormônios Juvenis/farmacologia , Aedes/crescimento & desenvolvimento , Animais , Relação Dose-Resposta a Droga , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Malásia
12.
Mol Divers ; 22(3): 647-655, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29572759

RESUMO

In designing of novel insect growth regulators (IGRs), biologically occurring carvacrol has been structurally modified to thiadiazole and oxadiazole moieties. Two series of carvacrol analogs containing 1,3,4-thiadiazole (VIIIa-e) and 1,3,4-oxadiazole (IXa-e) derivatives are designed and synthesized. Their structures are confirmed by FT-IR, [Formula: see text] NMR, [Formula: see text]C NMR and LC-MS. IGR activity is tested against Spodoptera litura. Several analogs displayed IGR activity against this insect pest. Compounds VIIIe and IXe displayed relatively good IGR activity with [Formula: see text]values 117.43 and 108.83 ppm against Spodoptera litura, respectively. Synthesis, characterization and evaluation of carvacrol-based 1,3,4-thiadiazole and 1,3,4-oxadiazole derivatives as potent insect growth regulators (IGRs).


Assuntos
Hormônios Juvenis/farmacologia , Monoterpenos/farmacologia , Oxidiazóis/farmacologia , Spodoptera/efeitos dos fármacos , Tiadiazóis/farmacologia , Animais , Hormônios Juvenis/química , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Monoterpenos/química , Oxidiazóis/química , Pupa/efeitos dos fármacos , Pupa/crescimento & desenvolvimento , Spodoptera/crescimento & desenvolvimento , Tiadiazóis/química
13.
Biochim Biophys Acta Gen Subj ; 1862(5): 1148-1156, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29452235

RESUMO

BACKGROUND: Bombyx mori silk fibers with thin diameters have advantages of lightness and crease-resistance. Many studies have used anti-juvenile hormones to induce trimolters in order to generate thin silk; however, there has been comparatively little analysis of the morphology, structure and mechanical properties of trimolter silk. METHODS: This study induced two kinds of trimolters by appling topically anti-juvenile hormones and obtained thin diameter silk. Scanning electron microscope (SEM), FTIR analysis, tensile mechanical testing, chitin staining were used to reveal that the morphology, conformation and mechanical property of the trimolter silk. RESULTS: Cocoon of trimolters were highly densely packed by thinner fibers and thus had small apertures. We found that the conformation of trimolter silk fibroin changed and formed more ß-sheet structures. In addition, analysis of mechanical parameters yielded a higher Young's modulus and strength in trimolter silk than in the control. By chitin staining of silk gland, we postulated that the mechanical properties of trimolters' silk was enhanced greatly during to the structural changes of silk gland. CONCLUSION: We induced trimolters by anti-juvenile hormones and the resulting cocoons were more closely packed and had smaller silk fiber diameters. We found that the conformation of trimolters silk fibroin had a higher content of ß-sheet structures and better mechanical properties. GENERAL SIGNIFICANCE: Our study revealed the structures and mechanical properties of trimolter silk, and provided a valuable reference to improve silk quality by influencing molting in silkworms.


Assuntos
Bombyx/metabolismo , Imidazóis/farmacologia , Hormônios Juvenis/antagonistas & inibidores , Seda/biossíntese , Seda/química , Animais , Bombyx/química , Módulo de Elasticidade , Hormônios Juvenis/metabolismo , Hormônios Juvenis/farmacologia
14.
Chemosphere ; 195: 810-816, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29289908

RESUMO

Short-term pulsed exposure tests have been increasingly used to evaluate the ecotoxicity of pollutants of which concentrations vary over time in the field. In pulsed exposure, time-weighted average (TWA) concentration is often used as an index of exposure. However, there have been few studies to demonstrate whether TWA concentration can be used to evaluate the effect of endocrine-disrupting chemicals on the daphnids. Pyriproxyfen is one of the juvenile hormone analogs that induces daphnids to produce male offspring. To evaluate whether peak or TWA concentration can explain the effects of pyriproxyfen on daphnid reproduction, we measured the number of offspring and the proportion of male offspring produced by Daphnia magna during 21-day under different exposure treatments, constant, single-pulse, and multi-pulse exposure, at an equivalent TWA concentration. Constant exposure of 50 ng/L pyriproxyfen did not affect either the fecundity or the proportion of male offspring, while a single-pulse exposure of 525 ng/L pyriproxyfen over 2 day at four different age did not reduce fecundity, but the proportion of male offspring increased age dependently. Multi-pulses exposure of 131 ng/L pyriproxyfen over two days four times (total eight days) resulted in a decrease in fecundity and the highest proportion of male offspring. Daily observation demonstrated that male offspring was only produced several days after the exposure to a certain concentration of pyriproxyfen. Therefore, neither TWA nor peak concentration accurately evaluated the effects of pulsed exposure of pyriproxyfen on the reproduction of D. magna, particularly its effect on the proportion of male offspring.


Assuntos
Daphnia/efeitos dos fármacos , Hormônios Juvenis/farmacologia , Piridinas/farmacologia , Reprodução/efeitos dos fármacos , Animais , Daphnia/fisiologia , Disruptores Endócrinos/farmacologia , Feminino , Fertilidade/efeitos dos fármacos , Hormônios Juvenis/análise , Masculino , Piridinas/análise
15.
Sci Rep ; 8(1): 1426, 2018 01 23.
Artigo em Inglês | MEDLINE | ID: mdl-29362416

RESUMO

Juvenile hormones (JH) and ecdysteroids regulate many biological and metabolic processes. CREB-binding protein (CBP) is a transcriptional co-regulator with histone acetyltransferase (HAT) activity. Therefore, CBP is involved in activation of many transcription factors that regulate expression of genes associated with postembryonic development in insects. However, the function of CBP in JH action in insects is not well understood. Hence, we studied the role of CBP in JH action in the red flour beetle, Tribolium castaneum and the Tribolium cell line. CBP knockdown caused a decrease in JH induction of genes, Kr-h1, 4EBP and G13402 in T. castaneum larvae, adults and TcA cells whereas, Trichostatin A [TSA, a histone deacetylase (HDAC) inhibitor] induced the expression of these JH-response genes. Western blot analysis with specific antibodies revealed the requirement of CBP for the acetylation of H3K18 and H3K27 in both T. castaneum and TcA cells. Chromatin immunoprecipitation (Chip) assays showed the importance of CBP-mediated acetylation of H3K27 for JH induction of Kr-h1, 4EBP, and G13402 in TcA cells. These data suggest that CBP plays an important role in JH action in the model insect, T.castaneum.


Assuntos
Proteína de Ligação a CREB/genética , Hormônios Juvenis/farmacologia , Tribolium/crescimento & desenvolvimento , Acetilação , Animais , Proteína de Ligação a CREB/metabolismo , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Técnicas de Inativação de Genes , Histonas/metabolismo , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Tribolium/genética , Tribolium/metabolismo
16.
Pest Manag Sci ; 74(6): 1394-1403, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29205800

RESUMO

BACKGROUND: 20-Hydroxyecdysone (20E), a crucial insect steroid hormone, can bind to its cognate nuclear receptor composed of ecdysone receptor (EcR) and ultraspiracle (USP) to activate expression of 20E-response genes, enabling subsequent metamorphosis. In this study, we tried to find out which steroid-like compounds can block insect metamorphosis effectively and provide useful information for biopesticide study. For this purpose, we screened 126 steroid-like compounds for possible 20E antagonists using a dual-luciferase reporter assay with Drosophila melanogaster Kc and Bombyx mori Bm12 cells. RESULTS: Among 126 steroid-like compounds, three cucurbitacins (CucB, D and E) were identified as 20E antagonists in both Kc and Bm12 cells. Notably, CucB caused significant molting defects and mortality in both B. mori and D. melanogaster larvae, and dramatically hindered larval growth of Helicoverpa armigera by its anti-feeding activity. CONCLUSION: In vivo and in vitro experiments demonstrate that CucB acts as a potential insect growth regulator by antagonizing 20E activity and thus blocking molting and metamorphosis induced by 20E signaling. © 2017 Society of Chemical Industry.


Assuntos
Drosophila melanogaster/efeitos dos fármacos , Ecdisterona/antagonistas & inibidores , Hormônios Juvenis/farmacologia , Mariposas/efeitos dos fármacos , Triterpenos/farmacologia , Animais , Bombyx/efeitos dos fármacos , Bombyx/crescimento & desenvolvimento , Drosophila melanogaster/crescimento & desenvolvimento , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Metamorfose Biológica/efeitos dos fármacos , Mariposas/crescimento & desenvolvimento
17.
Gen Comp Endocrinol ; 258: 134-139, 2018 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-28554733

RESUMO

The endocrine stress response in Drosophila includes catecholamines, juvenile hormone (JH), 20-hydroxyecdysone (20E) and the insulin/insulin-like growth factor signalling pathway (IIS). Several changes in the IIS and hormonal status that occur under unfavourable conditions are universal and do not depend on the nature of stress exposure. The reviewed studies on the impact of different element of the Drosophila IIS, such as insulin-like receptor, the homologue of its substrate, CHICO, the transcription factor dFOXO and insulin like peptide 6, on the hormonal status suggest that the IIS controls catecholamine metabolism indirectly via JH, and there is a feedback loop in the interaction of JH and IIS. Moreover, at least one of the ways in which the IIS is involved in the control of stress resistance is mediated through JH/dopamine signalling.


Assuntos
Drosophila melanogaster/metabolismo , Insulina/metabolismo , Estresse Fisiológico , Animais , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/genética , Regulação da Expressão Gênica/efeitos dos fármacos , Insulina/farmacologia , Insulina/fisiologia , Hormônios Juvenis/metabolismo , Hormônios Juvenis/farmacologia , Receptor de Insulina/metabolismo , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Somatomedinas/metabolismo , Estresse Fisiológico/efeitos dos fármacos
18.
Insect Sci ; 25(2): 235-240, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27763722

RESUMO

Methoprene, a juvenile hormone (JH) analog, is a widely used insecticide that also accelerates behavioral development in honey bees (Apis mellifera). JH regulates the transition from nursing to foraging in adult worker bees, and treatment with JH or methoprene have both been shown to induce precocious foraging. To determine how methoprene changes honey bee behavior, we compared JH titers of methoprene-treated and untreated bees. Behavioral observations confirmed that methoprene treatment significantly increased the number of precocious foragers in 3 out of 4 colonies. In only 1 out of 4 colonies, however, was there a significant difference in JH titers between the methoprene-treated and control bees. Further, in all 4 colonies, there was no significant differences in JH titers between precocious and normal-aged foragers. These results suggest that methoprene did not directly affect the endogenous JH secreted by corpora allata. Because methoprene caused early foraging without changing workers' JH titers, we conclude that methoprene most likely acts directly on the JH receptors as a substitute for JH.


Assuntos
Abelhas/efeitos dos fármacos , Comportamento Animal/efeitos dos fármacos , Hormônios Juvenis/metabolismo , Metoprene/farmacologia , Animais , Abelhas/metabolismo , Hormônios Juvenis/farmacologia
19.
BMC Genomics ; 18(1): 996, 2017 12 29.
Artigo em Inglês | MEDLINE | ID: mdl-29284404

RESUMO

BACKGROUND: Juvenile hormones (JH) and ecdysteroids control postembryonic development in insects. They serve as valuable targets for pest management. Hence, understanding the molecular mechanisms of their action is of crucial importance. CREB-binding protein (CBP) is a universal transcriptional co-regulator. It controls the expression of several genes including those from hormone signaling pathways through co-activation of many transcription factors. However, the role of CBP during postembryonic development in insects is not well understood. Therefore, we have studied the role of CBP in postembryonic development in Tribolium, a model coleopteran insect. RESULTS: CBP is ubiquitously expressed in the red flour beetle, Tribolium castaneum. RNA interference (RNAi) mediated knockdown of CBP resulted in a decrease in JH induction of Kr-h1 gene expression in Tribolium larvae and led to a block in their development. Moreover, the injection of CBP double-stranded RNA (dsRNA) showed lethal phenotypes within 8 days of injection. RNA-seq and subsequent differential gene expression analysis identified CBP target genes in Tribolium. Knockdown of CBP caused a decrease in the expression of 1306 genes coding for transcription factors and other proteins associated with growth and development. Depletion of CBP impaired the expression of several JH response genes (e.g., Kr-h1, Hairy, early trypsin) and ecdysone response genes (EcR, E74, E75, and broad complex). Further, GO enrichment analyses of the downregulated genes showed enrichment in different functions including developmental processes, pigmentation, anatomical structure development, regulation of biological and cellular processes, etc. CONCLUSION: These data suggest diverse but crucial roles for CBP during postembryonic development in the coleopteran model insect, Tribolium. It can serve as a target for RNAi mediated pest management of this stored product pest.


Assuntos
Proteína de Ligação a CREB/fisiologia , Proteínas de Insetos/fisiologia , Tribolium/crescimento & desenvolvimento , Animais , Proteína de Ligação a CREB/antagonistas & inibidores , Proteína de Ligação a CREB/genética , Proteína de Ligação a CREB/metabolismo , Expressão Gênica , Proteínas de Insetos/antagonistas & inibidores , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Hormônios Juvenis/farmacologia , Larva/genética , Larva/metabolismo , Interferência de RNA , Tribolium/genética , Tribolium/metabolismo
20.
Sci Rep ; 7(1): 16542, 2017 11 29.
Artigo em Inglês | MEDLINE | ID: mdl-29185447

RESUMO

Juvenile hormones (JHs) are crucial regulators for multiple physiological processes in insects. In the current study, 10 genes in mevalonate pathway involved in JH biosynthesis were identified from Helicoverpa armigera. Tissue-specific expression analysis showed that six genes were highly expressed in the head which contained the JH biosynthetic gland (corpora allata). Temporal expression pattern showed that 10 of 12 genes were highly transcribed in the late 2nd-instar when the in vivo JH titer reached the peak, indicating a tight correlation between JH titer and the transcription of JH synthetic pathway genes. Moreover, ingestion of methoprene, a JH analogue, significantly suppressed the transcription of nine JH biosynthetic genes and caused a feedback upregulation of the JH degradation enzyme. Particularly, the Acetoacetyl CoA thiolase (HaAce) and Farnesyl diphosphate synthase gene 4 (HaFpps4) showed high transcript abundance, and their temporal expressions keep pace with JH fluctuations. Further study by RNAi showed that knockdown of HaFpps4 caused the decrease of JH titer, led to a negative effect on the transcript levels of other genes in JH pathway, and resulted in molting disturbance in larvae. Altogether, these results contribute to our understanding of JH biosynthesis in H. armigera and provide target genes for pest control based on JH-dependent regulation.


Assuntos
Hormônios Juvenis/farmacologia , Mariposas/metabolismo , Acetil-CoA C-Acetiltransferase/genética , Acetil-CoA C-Acetiltransferase/metabolismo , Animais , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Regulação da Expressão Gênica no Desenvolvimento/genética , Geraniltranstransferase , Metoprene/farmacologia , Mariposas/genética , Interferência de RNA
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