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1.
Ecotoxicol Environ Saf ; 193: 110324, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32088548

RESUMO

This study assessed the transcription levels of estrogen-responsive genes, such as vitellogenins (Vtg1 and Vtg2), choriogenins (ChgL, ChgH, and ChgHm), cytochrome P450 aromatase (CYP19a1b), and ER subtypes (ERα, ERß1, and ERß2), in 7 days-post-fertilization (dpf) embryos and 9 and 12 dpf larvae of medaka (Oryzias latipes) exposed to estrogenic endocrine-disrupting chemicals (EDCs). The <5 h-post-fertilization embryos were exposed to EDCs such as 17ß-estradiol (E2), p-n-nonylphenol (NP), and bisphenol A (BPA). In E2 (0.10-222 nM)-treated 7 dpf embryos and 9 or 12 dpf larvae, ChgL, ChgH, and ChgHm expression was up-regulated in a concentration-dependent manner. By contrast, interestingly, Vtg1 and Vtg2 expression was not induced in E2-treated 7 dpf embryos but was significantly induced in 9 and 12 dpf larvae, suggesting a developmental-stage-specific regulatory mechanism underlying Vtg expression. The maximum concentrations of NP (0.09-1.5 µM) and BPA (1.8-30 µM) up-regulated Chg expression in 9 or 12 dpf larvae, and the relative estrogenic potencies (REPs) of E2, NP, and BPA were 1, 2.1 × 10-4, and 1.0 × 10-5, respectively. Chg messenger RNA (mRNA) in medaka embryos and larvae can be used as a sensitive biomarker for screening potential estrogenic EDCs. Our assay system using embryos and larvae can be used as an in vivo alternative model because independent feeding stages (e.g., embryonic and early larval stages) are suitable alternatives.


Assuntos
Proteínas do Ovo/biossíntese , Disruptores Endócrinos/toxicidade , Estrogênios/toxicidade , Oryzias/embriologia , Oryzias/crescimento & desenvolvimento , Animais , Aromatase/biossíntese , Aromatase/genética , Compostos Benzidrílicos/toxicidade , Proteínas do Ovo/genética , Embrião não Mamífero/efeitos dos fármacos , Embrião não Mamífero/metabolismo , Estradiol/toxicidade , Receptor alfa de Estrogênio/metabolismo , Receptor beta de Estrogênio/biossíntese , Receptor beta de Estrogênio/genética , Larva/efeitos dos fármacos , Larva/genética , Larva/metabolismo , Masculino , Modelos Animais , Oryzias/genética , Fenóis/toxicidade , RNA Mensageiro/metabolismo , Transcrição Genética/efeitos dos fármacos , Vitelogeninas/biossíntese , Vitelogeninas/genética
2.
Chemosphere ; 238: 124589, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31437630

RESUMO

Vitellogenin (VTG), a well-established biomarker for the diagnosis of endocrine activity in fish, is used in multiple OECD test guidelines (TG) to identify activities of chemicals on hormonal pathways. However, the synthesis of VTG may not only be modified by typical endocrine-related pathways, but also through non-endocrine-mediated processes. In particular, hepatotoxicity, i.e. toxicant-induced impairment of liver structure and function, might influence VTG as a biomarker, since VTG is synthesized in hepatocytes. An intimate understanding of the interplay between endocrine-related and non-endocrine-related pathways influencing VTG production is crucial for the avoidance of erroneous diagnoses in hazard assessment for regulatory purposes of chemical compounds. In order to investigate whether hepatotoxicity may interfere with hepatic VTG synthesis, adult zebrafish (Danio rerio) were exposed to three well-known hepatotoxicants, acetaminophen, isoniazid and acetylsalicylic acid, according to OECD TG 230. Various hepatotoxicity- and endocrine system-related endpoints were recorded: mRNA expression of selected endocrine- and hepatotoxicity-related marker genes in the liver; VTG levels in head/tail homogenates; and liver histopathology. All three test compounds induced significant, but mild single cell necrosis of hepatocytes and transcriptional changes of hepatotoxicity-related marker genes, thus confirming hepatotoxic effects. A positive correlation between hepatotoxicity and reduced hepatic VTG synthesis was not observed, with the single exception of a weak increase in female zebrafish exposed to APAP. This suggests that - in studies conducted according to OECD TG 229 or 230 - it is unlikely that hepatotoxic chemicals will interfere with the hepatic capacity for VTG synthesis.


Assuntos
Acetaminofen/toxicidade , Aspirina/toxicidade , Hepatócitos/metabolismo , Isoniazida/toxicidade , Vitelogeninas/biossíntese , Poluentes Químicos da Água/toxicidade , Peixe-Zebra/metabolismo , Animais , Doença Hepática Induzida por Substâncias e Drogas , Sistema Endócrino/efeitos dos fármacos , Feminino , Hepatócitos/efeitos dos fármacos , Masculino , Proteínas de Peixe-Zebra/biossíntese
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.
Artigo em Inglês | MEDLINE | ID: mdl-31022468

RESUMO

Juvenile hormones (JH) regulate wide-ranging physiological and developmental processes in insects. However, molecular mechanisms underlying JH signaling remain to be determined. Vitellogenin (Vg) is primarily an egg-yolk protein, but recently proposed to serve many functions in insects. In the female American cockroach (Periplaneta americana), vitellogenin (Vg) genes are activated by JH III and suppressed by 20-hydroxyecdysone (20E) via cis-regulatory elements in a dose-dependent manner. In the present study, the upstream promoter region (935 bp) of Vg1 was cloned to elucidate the action of these hormones. A luciferase reporter assay identified an 81 bp region in the promoter region of Vg1 (-120 to -39 bp) that we found to be critical for JH III activation and 20E suppression. This 81 bp region contains a direct repeat separated by a 2-nucleotide spacer-designated Vg1HRE- that is similar to the Drosophila ecdysone response element direct repeat 4. Moreover, nuclear proteins isolated from nymphs, males, females, and Sf9 cells successfully bound to Vg1HRE, while binding was outcompeted by a 100-fold excess of cold probe or dephosphorylated nuclear protein extracts. In addition, binding was outcompeted by other ecdysone and JH response elements with similar half-site sequences (direct repeats) but to varying extents. Ultimately, we postulate that JH III indirectly activates Vg expression by interfering with or inhibiting the phosphorylation of nuclear proteins bound to Vg1HRE. Involvement of JH III in both induction of Vg1 and control of nuclear proteins binding to Vg1HRE suggest the latter to play an important role in JH signaling.


Assuntos
Regulação da Expressão Gênica , Proteínas de Insetos , Periplaneta , Sequências Repetitivas de Ácido Nucleico , Elementos de Resposta , Vitelogeninas , Animais , Feminino , Proteínas de Insetos/biossíntese , Proteínas de Insetos/genética , Hormônios Juvenis/genética , Hormônios Juvenis/metabolismo , Masculino , Ninfa , Periplaneta/genética , Periplaneta/metabolismo , Transdução de Sinais/genética , Vitelogeninas/biossíntese , Vitelogeninas/genética
5.
Environ Pollut ; 244: 247-256, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30340169

RESUMO

The pyrethroid deltamethrin and the organophosphate insecticide dimethoate are widely used in agriculture and in urban areas. Both plant protection products (PPPs) unintendedly result in adverse effects in pollinators. Currently, the sublethal effects of both compounds are poorly known, particularly on the molecular and biochemical level. Here we analysed effects of deltamethrin and dimethoate at environmental and sublethal concentrations in honey bee workers by focusing on transcriptional changes of target genes in the brain. In addition, expression of vitellogenin protein and activity of acetylcholinesterase were assessed upon dimethoate exposure to assess physiological effects. Deltamethrin resulted in induction of the cyp9q2 transcript at 0.53 ng/bee, while dimethoate led to induction of vitellogenin on the mRNA and protein level at 2 ng/bee. Transcripts of additional cytochrome P450-dependent monooxygenases (cyps) and genes related to immune system regulation were not differentially expressed upon PPP exposure. Dimethoate but not deltamethrin led to a strong and concentration-related inhibition of the acetylcholinesterase at 2 and 20 ng/bee. Our data demonstrate that deltamethrin and dimethoate exhibit transcriptional effects at environmental concentrations in the brain of honey bees. Dimethoate also strongly affected physiological traits, which may translate to adverse effects in forager bees.


Assuntos
Abelhas , Encéfalo/metabolismo , Dimetoato/efeitos adversos , Expressão Gênica/efeitos dos fármacos , Nitrilos/efeitos adversos , Piretrinas/efeitos adversos , Animais , Inibidores da Colinesterase/efeitos adversos , Sistema Enzimático do Citocromo P-450/metabolismo , Vitelogeninas/biossíntese
6.
Artigo em Inglês | MEDLINE | ID: mdl-29496550

RESUMO

Pituitary-hormone signaling plays critical roles in the onset and progression of gametogenesis in vertebrates. This study characterized expression patterns of pituitary gonadotropin beta-subunits (fshb and lhb), brain-type aromatase (cyp19a1b), androgen (ar1, ar2) and estrogen receptors (esr1, esr2a, esr2b), and changes in plasma steroid levels by liquid chromatography/tandem mass spectrometry in wild sablefish (Anoplopoma fimbria, order Scorpaeniformes) during a complete reproductive cycle. Transcripts for fshb increased during early gametogenesis and peaked in late vitellogenic females and late recrudescent males, while expression of lhb reached maximum levels in periovulatory and spermiating fish. Pituitary levels of cyp19a1b and ar1 were strongly correlated with those of lhb in females and males, increasing during gametogenesis and reaching maximum levels prior to spawning. By contrast, expression of ar2, and the three estrogen receptors differed between female and male sablefish. 17ß-estradiol (E2) was the dominant steroid in females during vitellogenesis, while a range of at least 6 steroids (11ß-hydroxyandrostenedione, testosterone [T], E2, 11-ketotestosterone [11KT], 11-deoxycortisol, and 17α,20ß,21-trihydroxyprogesterone) were detected at similar levels in males during testicular development. Prior to spawning, a marked increase in 4-androstenedione, T, 11KT and E2 was found in both periovulatory females and spermiating males. In conclusion, the concomitant changes in plasma androgen levels and pituitary ar1 expression during gametogenesis suggest a specific role for androgens in pituitary hormone regulation of reproduction in sablefish. Further, our data highlight the importance of E2 during final stages of maturation in this species, which may regulate the transcription of pituitary lhb in a paracrine fashion.


Assuntos
Aromatase/metabolismo , Encéfalo/enzimologia , Peixes/fisiologia , Hormônios Esteroides Gonadais/metabolismo , Gonadotropinas Hipofisárias/metabolismo , Oogênese , RNA Mensageiro/genética , Receptores Androgênicos/genética , Receptores Estrogênicos/genética , Estações do Ano , Espermatogênese , Espermatozoides/citologia , Esteroides/sangue , Animais , Feminino , Peixes/metabolismo , Masculino , Hipófise/enzimologia , Hipófise/metabolismo , Esteroides/metabolismo , Espectrometria de Massas em Tandem , Vitelogeninas/biossíntese
7.
PLoS One ; 13(3): e0194459, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29590153

RESUMO

Vitellogenesis is the process of yolk formation via accumulating vitellin (Vn) with nutrients in the oocytes. Expression of vitellogenin (Vg), the precursor of Vn, is one of the indicators for the start of vitellogenesis. In Pacific white shrimp (Litopenaeus vannamei), the type-II vitellogenesis-inhibiting hormone (VIH-2) effectively suppresses hepatopancreatic Vg mRNA expression. In this study, we demonstrate the increasing transcript levels of hepatopancreatic Vg during L. vannamei ovarian development, suggesting that the hepatopancreas-derived Vg/Vn may also contribute to vitellogenesis in this species. Using a combination of in vivo injections and in vitro primary cell cultures, we provide evidences that the inhibition of VIH-2 on hepatopancreatic Vg gene expression is mediated through a functional coupling of the GC/cGMP pathway with different MAPK-dependent cascades in female shrimp. In VIH-2 signaling, the NO-independent GC/cGMP/PKG cascades were upstream of the MAPKs. Activations of the MAPK signal by VIH-2 include the phosphorylation of JNK and the mRNA/protein expression of P38MAPK. Additionally, the cAMP/PKA pathway is another positive intracellular signal for hepatopancreatic Vg mRNA expression but is independent of its VIH-2 regulation. Our findings establish a model for the signal transduction mechanism of Vg regulation by VIH and shed light on the biological functions and signaling of the CHH family in crustaceans.


Assuntos
Proteínas de Artrópodes/biossíntese , Proteínas de Transporte/metabolismo , Hepatopâncreas/metabolismo , Hormônios de Invertebrado/metabolismo , Sistema de Sinalização das MAP Quinases/fisiologia , Penaeidae/metabolismo , Sistemas do Segundo Mensageiro/fisiologia , Transcrição Genética/fisiologia , Vitelogeninas/biossíntese , Animais , GMP Cíclico/metabolismo , Feminino
8.
Artigo em Inglês | MEDLINE | ID: mdl-29476823

RESUMO

Insect lipophorin receptor (LpR) belongs to the low-density lipoprotein receptor (LDLR) superfamily and plays an essential role in fecundity by mediating the incorporation of lipophorin into developing oocytes. Here we report the identification and characterization of a full-length cDNA encoding a putative LpR from the brown planthopper, Nilaparvata lugens. The deduced amino acid sequence of NlLpR possesses the conserved structural motifs of LDLR family members, and displays a high degree of similarity with sequences from other insect LpRs. NlLpR is transcribed throughout oogenesis with its maximum level on day 7 after adult female emergence. NlLpR is highly expressed in the fat body and ovary, with relative low levels in the head, epidermis and midgut. Knockdown of NlLpR using double-stranded RNA (dsRNA) led to decreased triacylglycerol (TAG) content, retarded development of ovaries and decreased fecundity. Further functional analyses revealed that NlLpR works through nutritional signaling pathway-dependent activation of S6 kinase to regulate vitellogenin (Vg) biosynthesis during vitellogenesis and oocyte development. Disrupting of ecdysone receptor (EcR) expression and 20-hydroxyecdysone (20E) topical application demonstrated that NlLpR is regulated by ecdysone at transcript level. These results suggest that LpR is essential for Vg synthesis in the fat body and lipid uptake by developing oocytes, thus playing a critical role in insect reproduction.


Assuntos
Hemípteros/fisiologia , Metabolismo dos Lipídeos , Receptores Citoplasmáticos e Nucleares/metabolismo , Vitelogeninas/biossíntese , Animais , DNA Complementar/genética , Ecdisterona/fisiologia , Corpo Adiposo/metabolismo , Feminino , Fertilidade , Regulação da Expressão Gênica no Desenvolvimento , Técnicas de Silenciamento de Genes , Inativação Gênica , Oócitos/metabolismo , Ovário/metabolismo , Filogenia , RNA Mensageiro/genética , Receptores Citoplasmáticos e Nucleares/química , Receptores Citoplasmáticos e Nucleares/genética , Transcrição Genética , Triglicerídeos/metabolismo
9.
PLoS One ; 12(11): e0187726, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29117233

RESUMO

Microsporidium Nosema ceranae is well known for exerting a negative impact on honey bee health, including down-regulation of immunoregulatory genes. Protein nutrition has been proven to have beneficial effects on bee immunity and other aspects of bee health. Bearing this in mind, the aim of our study was to evaluate the potential of a dietary amino acid and vitamin complex "BEEWELL AminoPlus" to protect honey bees from immunosuppression induced by N. ceranae. In a laboratory experiment bees were infected with N. ceranae and treated with supplement on first, third, sixth and ninth day after emergence. The expression of genes for immune-related peptides (abaecin, apidaecin, hymenoptaecin, defensin and vitellogenin) was compared between groups. The results revealed significantly lower (p<0.01 or p<0.001) numbers of Nosema spores in supplemented groups than in the control especially on day 12 post infection. With the exception of abacein, the expression levels of immune-related peptides were significantly suppressed (p<0.01 or p<0.001) in control group on the 12th day post infection, compared to bees that received the supplement. It was supposed that N. ceranae had a negative impact on bee immunity and that the tested amino acid and vitamin complex modified the expression of immune-related genes in honey bees compromised by infection, suggesting immune-stimulation that reflects in the increase in resistance to diseases and reduced bee mortality. The supplement exerted best efficacy when applied simultaneously with Nosema infection, which can help us to assume the most suitable period for its application in the hive.


Assuntos
Aminoácidos/administração & dosagem , Abelhas/efeitos dos fármacos , Fatores Imunológicos/administração & dosagem , Proteínas de Insetos/imunologia , Nosema/patogenicidade , Vitaminas/administração & dosagem , Animais , Peptídeos Catiônicos Antimicrobianos/biossíntese , Peptídeos Catiônicos Antimicrobianos/imunologia , Abelhas/imunologia , Abelhas/microbiologia , Defensinas/biossíntese , Defensinas/imunologia , Imunossupressão , Proteínas de Insetos/biossíntese , Nosema/crescimento & desenvolvimento , Nosema/imunologia , Fatores de Proteção , Vitelogeninas/biossíntese , Vitelogeninas/imunologia
10.
J Toxicol Environ Health A ; 80(16-18): 987-1001, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28849994

RESUMO

Fish are exposed to a complex mixture of endocrine disrupting compounds (EDC), some of which display antiestrogenic activity leading to suppression of estrogen receptor (ER)- mediated reproductive processes. Although the main mode of action (MoA) of these antiestrogens is to directly interfere with natural ligand binding of the ER, several other MoA have been proposed. The aim of the present study was to characterize single and combined antiestrogenic effects of the aryl hydrocarbon receptor (AhR)-agonist ß-naphthoflavone (BNF) and ER-antagonist 4-hydroxytamoxifen (OHT) on vitellogenin (Vtg) protein using primary rainbow trout (Oncorhynchus mykiss) hepatocytes. Supporting transcriptional analysis of ER-responsive genes (estrogen receptor-α (er-α), vitellogenin-1 (vtg-1), eggshell zona radiata protein (zrp)) and AhR-mediated genes (aryl hydrocarbon receptor-2ß, cytochrome p450-1a (cyp1a)) was performed by qPCR to characterize the antiestrogenic influence on ER- and AhR-mediated responses. Data demonstrated that both BNF and OHT significantly reduced 17ß-estradiol (E2)-induced Vtg protein expression in a concentration responsive manner, whereas exposure to a mixture of these produced an additive antiestrogenic effect. The results observed at the protein level were further supported by transcriptional analysis of ER-responsive genes (er-α, vtg-1, zrp), where only E2-induced vtg-1 gene expression was significantly decreased by OHT and the mixture of OHT and BNF. E2-induced er-α and zrp gene expression was not markedly altered. The significant reduction of E2-induced vtg-1 gene expression by OHT suggested that the antiestrogenic effect of this compound may be associated with ER signaling pathway. Specific genes involved in putative AhR-ER cross-talk were also investigated, however none were directly associated with the compound anti-estrogenic MoA. Although the MoA of the single compounds and mixture were not completely characterized, the present study enhanced our knowledge of the combined toxicity mediated by antiestrogens acting through different MoA.


Assuntos
Disruptores Endócrinos/toxicidade , Moduladores de Receptor Estrogênico/toxicidade , Hepatócitos/efeitos dos fármacos , Oncorhynchus mykiss/genética , Vitelogeninas/biossíntese , beta-Naftoflavona/toxicidade , Animais , Células Cultivadas , Citocromo P-450 CYP1A1/genética , Citocromo P-450 CYP1A1/metabolismo , Proteínas do Ovo/genética , Proteínas do Ovo/metabolismo , Estradiol/toxicidade , Receptor alfa de Estrogênio/genética , Receptor alfa de Estrogênio/metabolismo , Hepatócitos/metabolismo , Masculino , Oncorhynchus mykiss/metabolismo , Receptores de Hidrocarboneto Arílico/agonistas , Receptores de Hidrocarboneto Arílico/genética , Receptores de Hidrocarboneto Arílico/metabolismo , Receptores Estrogênicos/antagonistas & inibidores , Receptores Estrogênicos/genética , Receptores Estrogênicos/metabolismo , Transdução de Sinais , Tamoxifeno/análogos & derivados , Tamoxifeno/toxicidade
11.
Sci Rep ; 7(1): 7647, 2017 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-28794440

RESUMO

Guppy (Poecilia reticulata) is an ideal model for studying environmental estrogens, and its large caudal fin has a high capacity to regenerate. This study analyzed the feasibility of caudal fin for detecting vitellogenin (Vtg), the most commonly used biomarker of environmental estrogens. Firstly, a sandwich ELISA for guppy Vtg was developed using purified lipovitellin and its antibody and it had a working range of 7.8-1000 ng/mL and detection limit of 3.1 ng/mL. The ELISA was used to detect tissue distribution of Vtg. In male guppy exposed to 50 and 100 ng/L 17ß-estradiol (E2), Vtg concentration in caudal fin was higher than that in whole fish, brain, eyes, gonad, and skin, and was close to that in the liver. Furthermore, male guppies were exposed to environmental concentrations of 17a-ethinylestradiol (EE2) and bisphenol S (BPS) to validate the utility of caudal fin Vtg for detecting estrogenic activities. The lowest observed effect concentration of EE2 and BPS were lower than 2 ng/L and 1 µg/L, which were below or equal to the values reported for other species, demonstrating that caudal fin Vtg was highly sensitive to estrogenic chemicals. Therefore, caudal fins of guppies are suggested as alternative samples for Vtg biomarker detection.


Assuntos
Nadadeiras de Animais/metabolismo , Biomarcadores , Estrogênios/farmacologia , Poecilia/fisiologia , Vitelogeninas/biossíntese , Animais , Western Blotting , Proteínas do Ovo/análise , Proteínas do Ovo/biossíntese , Exposição Ambiental , Ensaio de Imunoadsorção Enzimática , Feminino , Masculino , Fenótipo , Vitelogeninas/análise
12.
Am J Trop Med Hyg ; 97(2): 477-480, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28722589

RESUMO

RNA interference caused by exogenous double-stranded RNA (dsRNA) is used to downregulate crucial genes to control insects. The reproductive success of all oviparous species depends on vitellogenin (Vg) biosynthesis and its accumulation in the developing oocytes. Adult females of Triatoma infestans were independently injected with two Vg dsRNAs (Vg1 dsRNA or Vg2 dsRNA) or nuclease-free water (control) 24 hours before feeding, and a group of adult females not injected was also analyzed (control). Vg1 and Vg2 messenger RNAs silencing was verified by reverse transcription quantitative polymerase chain reaction. The transcript levels of the Vg1 and Vg2 genes were significantly reduced after dsRNA treatment in fat body and ovary of T. infestans in relation to those detected in individuals injected with nuclease-free water and not injected (controls). Moreover, the present study demonstrated that the silencing of the Vg1 or Vg2 genes inhibits oviposition in the Chagas disease vector T. infestans. These findings may have important implications for the development of novel vector control strategies.


Assuntos
Doença de Chagas/transmissão , Inativação Gênica , Insetos Vetores/genética , Oviposição/genética , Triatoma/genética , Vitelogeninas/biossíntese , Vitelogeninas/genética , Animais , Feminino , Expressão Gênica , Genes de Insetos , Controle de Insetos/métodos
13.
Environ Toxicol Pharmacol ; 53: 177-183, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28645054

RESUMO

Endocrine disruptors, especially estrogen receptor (ER) agonists, have received considerable research attention. While there are several mechanistic endpoints for ER agonism in the Endocrine Disruptor Screening Program, there have been growing efforts to develop high-throughput screening assays and computational models to reduce testing cost, time, and animal use. For example, there are 16 ER agonist assays and an integrated computational model in ToxCast. In the present study, we examined the relationship between ToxCast ER agonist assays and model activity to male vitellogenin induction in the Fish-Short Term Reproduction Assay. It was found 15/16 of the assays significantly predicted potency ranks for 10 common ER agonists, and 7/16 of the assays had a significant linear correlation. The integrated model also provided comparable performance to most assays. Thus, the ToxCast ER agonist assays and model may be useful to identify endocrine disruptors and predict reproductive outcomes in fish.


Assuntos
Bioensaio , Disruptores Endócrinos/toxicidade , Estrogênios/toxicidade , Modelos Biológicos , Vitelogeninas/biossíntese , Animais , Peixes/metabolismo , Peixes/fisiologia , Masculino , Reprodutibilidade dos Testes , Reprodução/efeitos dos fármacos
14.
C R Biol ; 340(3): 139-144, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28242272

RESUMO

In the last years, the hormonal balance is threatened by the interferences of substances with hormone-like action (endocrine disruptor chemicals, EDCs) that may harm animal reproduction. Most EDCs are resistant to environmental degradation and are considered ubiquitous contaminants. EDCs may have synthetic or natural origins. Pesticides used in intensive agriculture contain large amounts of chemicals with estrogenic properties, such as the alkylphenol nonylphenol (NP). Besides, animal feeding operations are important sources of natural estrogen metabolites introduced into the environment through manure application in organic farming. In both cases, EDCs can reach animals, including humans particularly at risk due to their position in the food chain. This is the reason for which it is important to use terrestrial vertebrates as sentinels in soil biomonitoring programmes. Today, the most validated biomarker of estrogenic exposure is the expression in male liver of the vitellogenin (VTG), an estrogen-dependent glycolipophosphoprotein naturally expressed only in the liver of oviparous females during the reproductive season. This report summarizes the data available on the EDC-dependent expression and the synthesis of VTG in male vertebrates, highlighting our latest studies that demonstrate the ability of testis and epididymis of the lacertid Podarcis sicula to synthesize VTG following estrogenic exposure. These findings provide, for the first time, evidence on an extrahepatic expression and synthesis of VTG in a terrestrial vertebrate and lay the groundwork for a new value of the VTG as a biomarker of environmental contamination. In addition, the results open a new scenario on the role of VTG in cells other than oocytes.


Assuntos
Estrogênios/metabolismo , Vitelogeninas/biossíntese , Animais , Humanos , Masculino , Vertebrados/metabolismo
15.
J Biol Chem ; 292(21): 8823-8834, 2017 05 26.
Artigo em Inglês | MEDLINE | ID: mdl-28356351

RESUMO

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. The 78-kDa glucose-regulated protein (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.


Assuntos
Corpo Adiposo/metabolismo , Proteínas de Choque Térmico/biossíntese , Hormônios Juvenis/metabolismo , Locusta migratoria/metabolismo , Vitelogênese/fisiologia , Vitelogeninas/biossíntese , Animais , Feminino , Técnicas de Silenciamento de Genes , Proteínas de Choque Térmico/genética , Hormônios Juvenis/genética , Locusta migratoria/genética , Oócitos/metabolismo , Vitelogeninas/genética
16.
Ecotoxicol Environ Saf ; 141: 113-118, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28324817

RESUMO

MethylParaben (MP), a methyl ester of p-hydroxybenzoic acid, is used as an anti-microbial preservative in foods, drugs and cosmetics for decades. It enters the aquatic environment, and can have toxic effects on aquatic organisms. Little is known on the developmental toxicity of MP exposure to zebrafish during early life stages. In this study, the developmental effects of MP were evaluated in embryo-larval zebrafish (at concentrations ranging from 100µM, 200µM, 400µM, 800µM and 1000µM for 96h post fertilization (hpf). The survival, hatching, heart beat rate and developmental abnormalities were observed in the embryos exposed to MP. MP exposure resulted in decreased heart rate and hatching rate. Defects including pericardial edema blood cell accumulation and bent spine were observed in all the treated concentration, except at 100µM. With increasing concentrations, the frequency of these defects increased. The 96 hpf LC50 of MP was calculated to be 428µM (0.065mg/L). Furthermore, RT-PCR result showed that in larval zebrafish exposed to 100µM (0.015mg/L) of MP till 96 hpf, expression of vitellogenin I (Vtg -I) was significantly upregulated compared to the control group. This data suggest that even though lower concentrations of MP do not cause phenotypic malformations, it leads to dysregulated expression of estrogenic biomarker gene Vtg-I.


Assuntos
Embrião não Mamífero/efeitos dos fármacos , Disruptores Endócrinos/toxicidade , Parabenos/toxicidade , Vitelogeninas/biossíntese , Poluentes Químicos da Água/toxicidade , Peixe-Zebra/embriologia , Animais , Relação Dose-Resposta a Droga , Embrião não Mamífero/anormalidades , Embrião não Mamífero/metabolismo , Larva , Dose Letal Mediana , Reprodução/efeitos dos fármacos , Regulação para Cima , Vitelogeninas/genética , Peixe-Zebra/anormalidades , Peixe-Zebra/genética
17.
Mol Reprod Dev ; 84(5): 363-375, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28218427

RESUMO

Vitellogenenesis is a physiological process common in oviparous animals. The molecular profile, modifications, and utilization of vitellogenin (VTG), a precursor of yolk protein, have been characterized in various taxa to understand oogenesis within different modes of reproduction. Hormonal regulation of VTGs has been investigated in invertebrates, such as insects and crustaceans; conversely, little is known for cephalopods. In this study, we isolated two VTG genes (ue-VTG1 and ue-VTG2) from the loliginid swordtip squid, Uroteuthis edulis, via a comprehensive survey of a transcriptome database and subsequent cDNA cloning. Structural analysis of the two ue-VTGs revealed their unique features, namely the absence of two domains usually found in VTGs from other organisms: the von Willebrand factor D domain (vWD) and the domain of unknown function 1943 (DUF1943). Levels of ue-VTG1 and ue-VTG2 transcripts in the ovary, specifically in follicular cells, increased during the late-vitellogenic phase, suggesting that yolk accumulation progresses via paracrine interactions involving follicular cells and oocytes. N-terminal amino acid sequencing of biochemically purified yolk protein revealed its origins from these two VTGs, indicating that both are functional precursors of yolk protein. These results provide information that is essential to understanding the physiological pathway of yolk synthesis, accumulation, and storage in loliginid squids.


Assuntos
Decapodiformes , Regulação da Expressão Gênica/fisiologia , Oócitos/metabolismo , Vitelogênese/fisiologia , Vitelogeninas , Animais , Clonagem Molecular , Decapodiformes/genética , Decapodiformes/metabolismo , Feminino , Vitelogeninas/biossíntese , Vitelogeninas/genética
18.
Dev Biol ; 422(2): 105-114, 2017 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-28089848

RESUMO

The importance of juvenile hormone regulating insect oogenesis suggests looking for genes whose expression is regulated by this hormone. SPARC is a calcium-binding glycoprotein that forms part of the extracellular membranes, which in vertebrates participates in bones mineralization or regulating cell proliferation in some cancer types. This large number of functions described for SPARC in different species might be related to the significant differences in its structure observed when comparing different species-groups. Indeed, these structural differences allow characterizing the different clades. In the cockroach Blattella germanica, a SPARC homolog emerged from ovarian transcriptomes that were constructed to find genes responding to juvenile hormone. In insects, SPARC functions have been studied in oogenesis and in embryo development of Drosophila melanogaster. In the present work, using RNAi approaches, novel functions for SPARC in the B. germanica panoistic ovaries are described. We found that depletion of SPARC does not allow to the follicular cells to complete mitosis, resulting in giant follicular cells nuclei and in a great alteration of the ovarian follicle cytoskeleton. The SPARC contribution to B. germanica oogenesis occurs stabilizing the follicular cell program and helping to maintain the nuclear divisions. Moreover, SPARC is necessary to maintain the cytoskeleton of the follicular cells. Any modification of these key processes disables females for oviposition.


Assuntos
Blattellidae/embriologia , Citoesqueleto/metabolismo , Epitélio/fisiologia , Oogênese/fisiologia , Osteonectina/metabolismo , Folículo Ovariano/embriologia , Animais , Proliferação de Células , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Hormônios Juvenis/metabolismo , Mitose/fisiologia , Oogênese/genética , Osteonectina/genética , Folículo Ovariano/citologia , Folículo Ovariano/metabolismo , Interferência de RNA , RNA Interferente Pequeno/genética , Vitelogeninas/biossíntese
19.
Chemosphere ; 167: 282-290, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27728887

RESUMO

Industrial and municipal effluents regularly pollute water bodies and cause various toxic effects to aquatic life. Because of the diverse nature of industrial processes and domestic products, urban effluents are often tainted with various anthropogenic endocrine disrupting chemicals that may interfere with the reproductive physiology of aquatic fauna. In this study, we tested effluents from the City of Bulawayo for the presence of estrogenic endocrine disrupting chemicals and their effects on fish gonads and fecundity. Effluents were collected from two sewage treatment plants (STPs), which receive largest volume of industrial effluents from the City, and from a textile factory. Male and female zebrafish (Danio rerio) were exposed to effluents and analyzed for vitellogenin induction, gonad alterations, and fertility. Male zebrafish exposed to effluent from Thorngrove STP had significantly higher (p ≤ 0.05) vitellogenin compared to control. Textile effluent caused adverse gonad alterations such as oocyte atresia (females) and increased proportion of spermatogonia (males) which could lead to reduced fertility. Textile effluent (5% v/v) and Thorngrove effluent also caused a decline in fertilization success of breeding groups of zebrafish. The results of this study show the potential effects of effluent pollution and the occurrence of EDCs in developing countries. This underscores the need to effectively prevent pollution of environmental water bodies from industrial and municipal sewage treatment plant effluents. We recommend a follow-up study to monitor the effects of the effluents on feral fish in effluent polluted downstream dams of Bulawayo.


Assuntos
Disruptores Endócrinos/toxicidade , Estrogênios/toxicidade , Fertilidade/efeitos dos fármacos , Vitelogeninas/biossíntese , Poluentes Químicos da Água/toxicidade , Peixe-Zebra/crescimento & desenvolvimento , Animais , Disruptores Endócrinos/análise , Estrogênios/análise , Feminino , Gônadas/efeitos dos fármacos , Gônadas/crescimento & desenvolvimento , Masculino , Esgotos/química , Indústria Têxtil , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Peixe-Zebra/metabolismo , Zimbábue
20.
Elife ; 52016 11 29.
Artigo em Inglês | MEDLINE | ID: mdl-27894418

RESUMO

Animals require molecular signals to determine when to divert resources from somatic functions to reproduction. This decision is vital in animals that reproduce in an all-or-nothing mode, such as bristle worms: females committed to reproduction spend roughly half their body mass for yolk and egg production; following mass spawning, the parents die. An enigmatic brain hormone activity suppresses reproduction. We now identify this hormone as the sesquiterpenoid methylfarnesoate. Methylfarnesoate suppresses transcript levels of the yolk precursor Vitellogenin both in cell culture and in vivo, directly inhibiting a central energy-costly step of reproductive maturation. We reveal that contrary to common assumptions, sesquiterpenoids are ancient animal hormones present in marine and terrestrial lophotrochozoans. In turn, insecticides targeting this pathway suppress vitellogenesis in cultured worm cells. These findings challenge current views of animal hormone evolution, and indicate that non-target species and marine ecosystems are susceptible to commonly used insect larvicides.


Assuntos
Anelídeos/fisiologia , Encéfalo/fisiologia , Ácidos Graxos Insaturados/metabolismo , Hormônios/metabolismo , Reprodução , Animais , Transcrição Genética/efeitos dos fármacos , Vitelogeninas/biossíntese
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