BACKGROUND: Leishmaniasis is a group of neglected vector-borne diseases transmitted by phlebotomine sand flies. Leishmania parasites must overcome various defenses in the sand fly midgut, including the insects's immune response. Insect immunity is regulated by the ecdysone hormone, which binds to its nuclear receptor (EcR) and activates the transcription of genes involved in insect immunity. However, the role of ecdysone in sand fly immunity has never been studied. Phlebotomus perniciosus is a natural vector of Leishmania infantum; here, we manipulated its neuroendocrine system using azadirachtin (Aza), a natural compound known to affect ecdysone synthesis. METHODS: Phlebotomus perniciosus larvae and adult females were fed on food containing either Aza alone or Aza plus ecdysone, and the effects on mortality and ecdysis were evaluated. Genes related to ecdysone signaling and immunity were identified in P. perniciosus, and the expression of antimicrobial peptides (AMPs), EcR, the ecdysone-induced genes Eip74EF and Eip75B, and the transcription factor serpent were analyzed using quantitative polymerase chain reaction (PCR). RESULTS: Aza treatment inhibited molting of first-instar (L1) larvae to L2, with only 10% of larvae molting compared to 95% in the control group. Serpent and Eip74EF, attacin, defensin 1, and defensin 2 genes were downregulated by Aza treatment in larvae. Similarly, Aza-treated adult females also presented suppression of ecdysone signaling-related genes and the AMPs attacin and defensin 2. Notably, all gene repression caused by Aza was reversed by adding ecdysone concomitantly with Aza to the larval or female food, indicating that these genes are effective markers for ecdysone repression. CONCLUSIONS: These results highlight the critical role of ecdysone in regulating the development and immunity of P. perniciosus, which potentially could interfere with Leishmania infection.

• Klíčová slova
• Phlebotomus perniciosus, Antimicrobial peptides, Azadirachtin, Ecdysone,
• MeSH
• antimikrobiální peptidy genetika   farmakologie   MeSH
• ekdyson * MeSH
• hmyz - vektory účinky léků   genetika   parazitologie   imunologie   MeSH
• hmyzí proteiny genetika   metabolismus   MeSH
• larva * účinky léků   imunologie   genetika   MeSH
• limoniny * farmakologie   MeSH
• Phlebotomus * účinky léků   genetika   parazitologie   imunologie   MeSH
• shazování tělního pokryvu účinky léků   MeSH
• signální transdukce * účinky léků   MeSH
• zvířata MeSH
• Check Tag
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antimikrobiální peptidy MeSH
• azadirachtin MeSH Prohlížeč
• ekdyson * MeSH
• hmyzí proteiny MeSH
• limoniny * MeSH

The polyhydroxylated derivatives of 6-keto,7-dehydrocholesterol (ecdysone, ecdysteroids, Ecd) are natural compounds widely distributed in plants. They exhibit strong anabolic, vitamin D-like, pharmacological effects in vertebrate animals and in the human body. In the larval stages of insects, injections of pure Ecd cause serious pathophysiological, "hyperecdysonic" syndromes associated with neuromuscular paralysis, premature cuticular apolysis and complete inhibition of ecdysis. Ecds do not penetrate insect cuticle. For this reason, all previous attempts to induce ecdysone responses by topical applications of Ecd failed. In this work, we tried to induce the topical effects of Ecd by preparation of more lipophilic complexes, with 2 or 4 molecules of 20-hydroxyecdysone (E20) attached to a relatively large nucleus of the porphyrin. The resulting porphyrin-E20 complexes (ecdysogens) have been subjected to standardised assays for ecdysone activity in the ligatured larvae ("dauerlarvae") of the greater waxmoth (Galleria mellonella). Similarly like the free E20 alone, porphyrin-E20 complexes had no effect when applied on the body surface or administered in the larval diet. When injected, however, they exhibited delayed effects, but the adverse ("hyperecdysonic") pathophysiological syndromes were reduced or abolished. It is concluded, therefore, that the replacement of pathophysiological, precocious or "hyperecdysonic" moults by the larval-pupal transformation, was due to successive metabolic liberation of the biologically active, free E20 from the porphyrin-E20 complex. The biological status of Ecd does not agree with their definition as the prothoracic gland (PG) hormone of insects, nor with the assumptions about a growth hormone of plants. A possibility that the most important status of Ecd may depend on the pharmacological properties of a sterolic D6 vitamin has been discussed.

• Klíčová slova
• 20-hydroxyecdysone (E20), Ecdysone, Ecdysone bioassays, Ecdysteroids (Ecds), Galleria mellonella, Hyperecdysonic syndromes, Neuromuscular paralysis by Ecd,
• MeSH
• aplikace lokální MeSH
• aplikace orální MeSH
• biologická proměna účinky léků   MeSH
• ekdysteron aplikace a dávkování   chemie   farmakologie   fyziologie   MeSH
• kukla účinky léků   MeSH
• larva účinky léků   MeSH
• Lepidoptera účinky léků   fyziologie   MeSH
• porfyriny chemie   farmakologie   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• ekdysteron MeSH
• porfyriny MeSH

TAIMAN (TAI), the only insect ortholog of mammalian Steroid Receptor Coactivators (SRCs), is a critical modulator of ecdysone and juvenile hormone (JH) signaling pathways, which govern insect development and reproduction. The modulatory effect is mediated by JH-dependent TAI's heterodimerization with JH receptor Methoprene-tolerant and association with the Ecdysone Receptor complex. Insect hormones regulate insect physiology and development in concert with abiotic cues, such as photo- and thermoperiod. Here we tested the effects of JH and ecdysone signaling on the circadian clock by a combination of microsurgical operations, application of hormones and hormone mimics, and gene knockdowns in the linden bug Pyrrhocoris apterus males. Silencing taiman by each of three non-overlapping double-strand RNA fragments dramatically slowed the free-running period (FRP) to 27-29 hours, contrasting to 24 hours in controls. To further corroborate TAIMAN's clock modulatory function in the insect circadian clock, we performed taiman knockdown in the cockroach Blattella germanica. Although Blattella and Pyrrhocoris lineages separated ~380 mya, B. germanica taiman silencing slowed the FRP by more than 2 hours, suggesting a conserved TAI clock function in (at least) some insect groups. Interestingly, the pace of the linden bug circadian clock was neither changed by blocking JH and ecdysone synthesis, by application of the hormones or their mimics nor by the knockdown of corresponding hormone receptors. Our results promote TAI as a new circadian clock modulator, a role described for the first time in insects. We speculate that TAI participation in the clock is congruent with the mammalian SRC-2 role in orchestrating metabolism and circadian rhythms, and that TAI/SRCs might be conserved components of the circadian clock in animals.

• MeSH
• buněčná membrána MeSH
• cirkadiánní hodiny * genetika   MeSH
• cirkadiánní rytmus genetika   MeSH
• ekdyson genetika   MeSH
• hmyz MeSH
• juvenilní hormony genetika   MeSH
• savci MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• ekdyson MeSH
• juvenilní hormony MeSH

Structural modification of 20-hydroxyecdysone (20E) based on photochemical transformation yielded dimeric ecdysteroid 7alphaH,7'alphaH-bis-[(20R,22R)-2beta,3beta,20,22,25-pentahydroxy-5beta-cholest-8(14)-en-6-one-7-yl] as a main product. Its structure was determined by detailed NMR analysis. Furthermore, two new monomeric analogues: 14-epi-20-hydroxyecdysone and 14-deoxy-14,18-cyclo-20-hydroxyecdysone were identified in addition to the earlier described 14-deoxy and 14-hydroperoxy derivatives of 20E. Formation of the specific and so far unique ecdysteroid dimer has not been observed in earlier photo-transformation studies. The transformed dimeric analogue of 20-hydroxyecdysone retained the high agonistic activity on the ecdysone receptor in the B(II)-bioassay compared with the original 20E.

• MeSH
• dimerizace MeSH
• Drosophila melanogaster MeSH
• ekdysteroidy analogy a deriváty   MeSH
• ekdysteron chemická syntéza   chemie   MeSH
• fotochemie metody   MeSH
• magnetická rezonanční spektroskopie MeSH
• molekulární konformace MeSH
• molekulární modely MeSH
• spektrofotometrie infračervená MeSH
• steroidní receptory agonisté   MeSH
• vysokoúčinná kapalinová chromatografie MeSH
• vztahy mezi strukturou a aktivitou MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• ecdysone receptor MeSH Prohlížeč
• ekdysteroidy MeSH
• ekdysteron MeSH
• steroidní receptory MeSH

The steroid hormone ecdysone coordinates insect growth and development, directing the major postembryonic transition of forms, metamorphosis. The steroid-deficient ecdysoneless1 (ecd1) strain of Drosophila melanogaster has long served to assess the impact of ecdysone on gene regulation, morphogenesis, or reproduction. However, ecd also exerts cell-autonomous effects independently of the hormone, and mammalian Ecd homologs have been implicated in cell cycle regulation and cancer. Why the Drosophila ecd1 mutants lack ecdysone has not been resolved. Here, we show that in Drosophila cells, Ecd directly interacts with core components of the U5 snRNP spliceosomal complex, including the conserved Prp8 protein. In accord with a function in pre-mRNA splicing, Ecd and Prp8 are cell-autonomously required for survival of proliferating cells within the larval imaginal discs. In the steroidogenic prothoracic gland, loss of Ecd or Prp8 prevents splicing of a large intron from CYP307A2/spookier (spok) pre-mRNA, thus eliminating this essential ecdysone-biosynthetic enzyme and blocking the entry to metamorphosis. Human Ecd (hEcd) can substitute for its missing fly ortholog. When expressed in the Ecd-deficient prothoracic gland, hEcd re-establishes spok pre-mRNA splicing and protein expression, restoring ecdysone synthesis and normal development. Our work identifies Ecd as a novel pre-mRNA splicing factor whose function has been conserved in its human counterpart. Whether the role of mammalian Ecd in cancer involves pre-mRNA splicing remains to be discovered.

• MeSH
• buněčný cyklus genetika   MeSH
• Drosophila melanogaster genetika   MeSH
• ekdyson genetika   MeSH
• kultivované buňky MeSH
• larva genetika   MeSH
• mutace genetika   MeSH
• prekurzory RNA genetika   MeSH
• proteiny Drosophily genetika   MeSH
• ribonukleoproteiny malé jaderné genetika   MeSH
• sestřih RNA genetika   MeSH
• spliceozomy genetika   MeSH
• steroidy metabolismus   MeSH
• vývojová regulace genové exprese genetika   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• ecd protein, Drosophila MeSH Prohlížeč
• ekdyson MeSH
• prekurzory RNA MeSH
• proteiny Drosophily MeSH
• ribonukleoproteiny malé jaderné MeSH
• steroidy MeSH

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.

• Klíčová slova
• CBP, Ecdysone, Juvenile hormone, Kr-h1, RNA seq, RNAi, Tribolium,
• MeSH
• exprese genu MeSH
• hmyzí proteiny antagonisté a inhibitory   genetika   metabolismus   fyziologie   MeSH
• juvenilní hormony farmakologie   MeSH
• larva genetika   metabolismus   MeSH
• protein vázající CREB antagonisté a inhibitory   genetika   metabolismus   fyziologie   MeSH
• RNA interference MeSH
• Tribolium genetika   růst a vývoj   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Research Support, N.I.H., Extramural MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Názvy látek
• hmyzí proteiny MeSH
• juvenilní hormony MeSH
• protein vázající CREB MeSH

Steroid signaling underlies developmental processes in animals. Mutations that impair steroidogenesis in the fruit fly Drosophila melanogaster provide tools to dissect steroid hormone action genetically. The widely used temperature-sensitive mutation ecdysoneless(1) (ecd(1)) disrupts production of the steroid hormone ecdysone, and causes developmental and reproductive defects. These defects cannot be satisfactorily interpreted without analysis of the ecd gene. Here, we show that ecd encodes an as yet functionally undescribed protein that is conserved throughout eukaryotes. The ecd(1) conditional allele contains an amino acid substitution, whereas three non-conditional larval lethal mutations result in truncated Ecd proteins. Consistent with its role in steroid synthesis, Ecd is expressed in the ecdysone-producing larval ring gland. However, development of ecd-null early larval lethal mutants cannot be advanced by Ecd expression targeted to the ring gland or by hormone feeding. Cell-autonomous ecd function, suggested by these experiments, is evidenced by the inability of ecd(-) clones to survive within developing imaginal discs. Ecd is also expressed in the ovary, and is required in both the follicle cells and the germline for oocyte development. These defects, induced by the loss of ecd, provide the first direct evidence for a cell-autonomous function of this evolutionarily conserved protein.

• MeSH
• Drosophila genetika   růst a vývoj   MeSH
• ekdyson farmakologie   MeSH
• endokrinní žlázy růst a vývoj   metabolismus   MeSH
• larva MeSH
• letální geny MeSH
• molekulární sekvence - údaje MeSH
• mutace MeSH
• oogeneze účinky léků   genetika   MeSH
• ovarium růst a vývoj   metabolismus   MeSH
• proteiny Drosophily genetika   metabolismus   MeSH
• sekvence aminokyselin MeSH
• sekvenční homologie aminokyselin MeSH
• steroidy metabolismus   MeSH
• vývojová regulace genové exprese * MeSH
• zvířata MeSH
• Check Tag
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Názvy látek
• ecd protein, Drosophila MeSH Prohlížeč
• ekdyson MeSH
• proteiny Drosophily MeSH
• steroidy MeSH

To gain insights into how juvenile hormone (JH) came to regulate insect metamorphosis, we studied its function in the ametabolous firebrat, Thermobia domestica. Highest levels of JH occur during late embryogenesis, with only low levels thereafter. Loss-of-function and gain-of-function experiments show that JH acts on embryonic tissues to suppress morphogenesis and cell determination and to promote their terminal differentiation. Similar embryonic actions of JH on hemimetabolous insects with short germ band embryos indicate that JH's embryonic role preceded its derived function as the postembryonic regulator of metamorphosis. The postembryonic expansion of JH function likely followed the evolution of flight. Archaic flying insects were considered to lack metamorphosis because tiny, movable wings were evident on the thoraces of young juveniles and their positive allometric growth eventually allowed them to support flight in late juveniles. Like in Thermobia, we assume that these juveniles lacked JH. However, a postembryonic reappearance of JH during wing morphogenesis in the young juvenile likely redirected wing development to make a wing pad rather than a wing. Maintenance of JH then allowed wing pad growth and its disappearance in the mature juvenile then allowed wing differentiation. Subsequent modification of JH action for hemi- and holometabolous lifestyles are discussed.

• Klíčová slova
• differentiation, ecdysone, juvenile hormone, metamorphosis, myoglianin, precocene,
• Publikační typ
• časopisecké články MeSH
• preprinty MeSH

Insect Growth Regulators (IGRs) represent advanced, bio-rational insecticides. This Special Issue reflects progress in IGR development that has been enabled by insight into the molecular principles of biosynthetic or hormone signaling pathways. The unifying principle is aiming at processes and molecular targets that are unique to arthropods and ideally to narrower insect taxa representing pests or disease vectors. While some strategies of obtaining the desired compounds for chemical intervention rely on rational, structure-based design or computational power, others exploit technologies allowing automated, high-throughput screening of large chemical libraries. All avenues leading to selective and environmentally safe pest control are valid as we face the imminent threat of the declining world insect population.

• Klíčová slova
• biosynthesis, ecdysone, juvenile hormone, metamorphosis, molting, receptors,
• Publikační typ
• časopisecké články MeSH

Effects of methoprene and 20-hydroxyecdysone on the development and hemagglutination activity (HA) were studied in both sexes of two members of the Culex pipiens complex-anautogenous C. p. quinquefasciatus and autogenous C. p. molestus. Juvenile hormone analogue (methoprene) and 20-hydroxyecdysone caused developmental changes in both mosquito strains. High larval mortality, prolongation of intermolt period in each larval instar and in the pupal stage, and morphological changes in the larval-pupal and pupal-adult transformations were also observed. Developmental changes were accompanied with some differences in the HA. HA was found in both sexes of both experimental mosquito strains. The juvenile hormone analogue used in the larval stage caused significant decrease of HA in the gut of adults of both sexes. On the other hand, 20-hydroxyecdysone decreased HA only in the female gut. Results obtained indicate that HA depends on the sex, the studied organ, and the level of hormones.

• MeSH
• Culex účinky léků   fyziologie   MeSH
• ekdysteron farmakologie   MeSH
• hemaglutinace účinky léků   MeSH
• methopren farmakologie   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• ekdysteron MeSH
• methopren MeSH