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1.
Insect Biochem Mol Biol ; 116: 103264, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31707207

RESUMO

Elaborate regulation of tissue- and stage-specific expression of genes is prerequisite for insect development. The hormone 20-hydroxyecdysone (20E) initiates metamorphosis by regulating the expression of a series of genes. However, how 20E orderly regulates the pupa-specific expression of genes remains unclear. In this study, we report a regulatory mechanism for the pupa-specific expression of chitin synthase A 2b (CHSA-2b) in Bombyx mori. We found that Broad-Complex Z4 (BR-C Z4) was up-regulated by 20E just before pupation, while transcription factor FoxJ and CHSA-2b were up-regulated during the pupal stage. There is a Fox cis-regulatory element in the CHSA-2b promoter region, and FoxJ protein bound to this element, enhancing the CHSA-2b transcription during the pupal stage. In addition to CHSA-2b, FoxJ also up-regulated the expression of 16 out of 19 pupa-specific genes tested. However, at the prepupal stage, 20E-induced BR-C Z4 inhibited the FoxJ transcription, indirectly inhibiting the CHSA-2b transcription. These data suggest that at the pre-pupation stage, 20E-induced BR-C Z4 inhibited the expression of pupa-stage genes like CHSA-2b by inhibiting the expression of FoxJ; by the pupal stage, the expression of BR-C Z4 decreased, releasing its inhibition on FoxJ, which then up-regulated the expression of the pupa-specific genes. This study explains the elaborate regulation of the pupa-specific gene expression during metamorphosis in B. mori.


Assuntos
Bombyx/crescimento & desenvolvimento , Bombyx/genética , Quitina Sintase/genética , Fatores de Transcrição Forkhead/genética , Regulação da Expressão Gênica no Desenvolvimento , Proteínas de Insetos/genética , Animais , Quitina Sintase/metabolismo , Ecdisterona/metabolismo , Fatores de Transcrição Forkhead/metabolismo , Proteínas de Insetos/metabolismo , Metamorfose Biológica , Pupa/genética , Pupa/crescimento & desenvolvimento , Regulação para Cima , Asas de Animais/crescimento & desenvolvimento
2.
Insect Biochem Mol Biol ; 116: 103255, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31654713

RESUMO

Vacuolar-type H + -adenosine triphosphatases (V-ATPases) are indispensable for lysosome acidification and participate in autophagic processes. The steroid hormone 20-hydroxyecdysone (20E) predominantly induces autophagy and regulates insect larval molting and metamorphosis; however, the specific mechanism of lysosome acidification regulation by 20E remains unclear. Here, we showed that the developmental profiles of Bombyx V-ATPases were in accordance with autophagy occurrence and lysosome acidification in the fat body during larval-pupal metamorphosis. BmV-ATPase-A and BmV-ATPase-B were required for lysosome acidification and autophagic flux. Both 20E treatment and starvation were able to induce lysosome acidification. Furthermore, BmV-ATPase transcription was induced by 20E treatment and reduced by RNAi targeting the 20E receptor BmUsp. On the one hand, 20E upregulated the transcription of BmV-ATPases through inducing Bombyx transcription factor EB (TFEB) and its nuclear translocation; on the other hand, 20E inhibited mTOR signaling to induce the transcription and assembly of BmV-ATPase subunits. Overall, 20E induces lysosome acidification by upregulating the transcription and assembly of V-ATPase subunits via activating BmTFEB and cooperating with nutrient signaling. These findings improve our understanding of the regulatory mechanisms underlying lysosome acidification and autophagic flux in Bombyx mori.


Assuntos
Adenosina Trifosfatases/metabolismo , Bombyx/fisiologia , Ecdisterona/metabolismo , Corpo Adiposo/química , Proteínas de Insetos/metabolismo , Lisossomos/química , Animais , Bombyx/genética , Bombyx/crescimento & desenvolvimento , Larva/genética , Larva/crescimento & desenvolvimento , Larva/fisiologia , Metamorfose Biológica
3.
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
4.
Arch Insect Biochem Physiol ; 103(3): e21609, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31385626

RESUMO

Insect metamorphosis is regulated by two main hormones: ecdysone (20E), which promotes molting, and juvenile hormone (JH), which inhibits adult morphogenesis. The transduction mechanisms for the respective hormonal signals include the transcription factors Krüppel homolog 1 (Kr-h1) and E93, which are JH- and 20E-dependent, respectively. Kr-h1 is the main effector of the antimetamorphic action of JH, while E93 is a key promoter of metamorphosis. The ancestral regulatory axis of metamorphosis, which operates in insects with hemimetabolan (gradual) metamorphosis and is known as the MEKRE93 pathway, is based on Kr-h1 repression of E93. In the last juvenile stage, when the production of JH dramatically decreases, Kr-h1 expression is almost completely interrupted, E93 becomes upregulated and metamorphosis proceeds. The holometabolan (complete) metamorphosis mode of development includes the peculiar pupal stage, a sort of intermediate between the final larval instar and the adult stage. In holometabolan species, Broad-Complex (BR-C) transcription factors determine the pupal stage and E93 stimulates the expression of BR-C in the prepupa. The MEKRE93 pathway is conserved in holometabolan insects, which have added the E93/BR-C interaction loop to the ancestral (hemimetabolan) pathway during the evolution from hemimetaboly to holometaboly.


Assuntos
Proteínas de Drosophila/metabolismo , Fatores de Transcrição Kruppel-Like/metabolismo , Metamorfose Biológica/fisiologia , Fatores de Transcrição/metabolismo , Animais , Proteínas de Drosophila/genética , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Fatores de Transcrição Kruppel-Like/genética , Fatores de Transcrição/genética
5.
Chemosphere ; 240: 124910, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31561159

RESUMO

The micronucleus test has been applied for more than three decades in tadpoles, generating an early warning of environmental quality. In this study, we reviewed 48 articles on the micronucleus test in tadpoles, published between 1987 and 2018. The findings reveal that pesticides have been the main topic discussed in the induction of micronucleus and other nuclear abnormalities in anuran larvae to the detriment of the widespread use of compounds used in agriculture. In addition to pesticides, a number of other xenobiotic agents have been targeted for genotoxic damage, such as heavy metals, radiation and wastewater. An appeal is reported to environmental contaminants, which when released naturally into the environment or because of human activities may contaminate aquatic habitats, threatening populations of tadpoles that depend on these environments for their survival. Larvae can bioaccumulate these contaminants that cause progressive impacts, ranging from DNA damage to metamorphosis delays, as well as malformations. We found that Argentina is the main driving force for the application of this test in anuran larvae along with Brazil. Different erythrocyte malformations have been reported for the erythrocyte nuclear abnormalities test, binucleated cells, nuclear buds, notched, lobed, reniform, nuclear bebbled, anucleated, picnotic and apoptotic cells are the most cited. In summary, the presence of chemical or physical agents, along with other disturbances of the habitat, can have a significant impact on the life history of the species, contributing to the decline of anuran populations.


Assuntos
Anuros/genética , Ecotoxicologia/tendências , Eritrócitos/efeitos dos fármacos , Larva/efeitos dos fármacos , Larva/genética , Testes para Micronúcleos , Agricultura , Animais , Argentina , Brasil , Dano ao DNA , Ecossistema , Monitoramento Ambiental/métodos , Poluição Ambiental , Eritrócitos/patologia , Eritrócitos/fisiologia , Metais Pesados/toxicidade , Metamorfose Biológica/efeitos dos fármacos , Publicações Seriadas , Poluentes Químicos da Água/toxicidade
6.
J Insect Sci ; 19(6)2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31830272

RESUMO

The sycamore lace bug, Corythucha ciliata (Say) is an invasive pest infesting trees of the genus Platanus. Both adults and nymphs damage the foliage of sycamore trees. Nymphs cannot survive in low temperatures; however, the sycamore lace bug overwinters as adults. In this study, we analyzed the metabolite profiles of this pest to determine significantly regulated metabolites during paurometabolous development from nymphs to adults. The identification of metabolites is essential to convert analytical data into meaningful biological knowledge. A total of 62 metabolites were identified using GC-MS. Among them, 29 different metabolites showed differences in content among nymphs, adult females (AF), and adult males (AM). Five of the 29 metabolites, including caffeic acid, D-glucose, D-mannose, glycerol and aminooxyacetic acid, were significantly increased and nine of them were significantly decreased during the developmental stages from nymph to adult. In addition, we identified three novel aldo-keto reductase (AKR) genes that may play a significant role in the control of glycerol biosynthesis. Moreover, the characteristics and expression levels of these genes were analyzed. This study will provide us with the necessary information to improve our understanding of the changes in metabolites in C. ciliata during paurometabolous development.


Assuntos
Aldo-Ceto Redutases/metabolismo , Hemípteros/metabolismo , Metamorfose Biológica , Animais , Feminino , Hemípteros/genética , Hemípteros/crescimento & desenvolvimento , Masculino , Filogenia
7.
J Chem Ecol ; 45(10): 838-848, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31677136

RESUMO

Many aquatic organisms detect and avoid damage-released cues from conspecifics, but the chemical basis of such responses, and the effects of prolonged exposure to such cues, remain poorly understood. Injured tadpoles of the cane toad (Rhinella marina) produce chemical cues that induce avoidance by conspecific tadpoles; and chronic exposure to those cues decreases rates of tadpole survival and growth, and reduces body size at metamorphosis. Such effects suggest that we might be able to use the cane toads' alarm cue for biocontrol of invasive populations in Australia. In the present study, we examined behavioral and ecological effects of compounds that are present in cane toad tadpoles and thus, might trigger avoidance of crushed conspecifics. Four chemicals (L-Arg, L-Leu-L-Leu-OH, L-Leu-L-Ile-OH and suberic acid) induced behavioral avoidance in toad tadpoles at some (but not all) dosage levels, so we then exposed toad larvae to these chemicals over the entire period of larval development. Larval survival and size at metamorphosis were decreased by chronic exposure to crushed conspecifics (consistent with earlier studies), but not by exposure to any of the four chemicals. Indeed, L-Arg increased body size at metamorphosis. We conclude that the behavioral response to crushed conspecifics by cane toad tadpoles can be elicited by a variety of chemical cues, but that consistent exposure to these individual chemical cues does not affect tadpole viability or developmental trajectory. The optimal behavioral tactic of a tadpole may be to flee if it encounters even a single chemical cue likely to have come from an injured conspecific (indicative of predation risk), whereas the continuing presence of that single chemical (but no others) provides a less reliable signal of predation risk. Our data are consistent with results from studies on fish, that suggest a role for multiple chemicals in initiating alarm responses to damage-released cues.


Assuntos
Arginina/farmacologia , Aprendizagem da Esquiva/efeitos dos fármacos , Bufo marinus/fisiologia , Caprilatos/farmacologia , Ácidos Dicarboxílicos/farmacologia , Oligopeptídeos/farmacologia , Animais , Tamanho Corporal/efeitos dos fármacos , Bufo marinus/crescimento & desenvolvimento , Larva/crescimento & desenvolvimento , Larva/fisiologia , Metamorfose Biológica/efeitos dos fármacos , Oligopeptídeos/química
8.
J Insect Sci ; 19(5)2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31612946

RESUMO

Insect hormones regulate metamorphosis including that leading to sexual dimorphism. Using RNA-Seq, we discovered that the second-instar male larva (SM) of the white wax insect, Ericerus pela, have 5,968 and 8,620 differentially expressed transcripts compared with the second-instar female larva (SF) and the first-instar male larva (FM), respectively. The expression levels of genes involved in the apoptosis of old tissues and the reconstruction of new ones in the SM significantly enhanced, while the SF mainly has enhanced expression levels of anabolic genes such as chitin. We predicted that the second-instar larvae are the developmental origin of sexual dimorphic metamorphosis. Meanwhile, in the juvenile hormone (JH) metabolic pathway, CYP15A1 and JH esterase (JHE) are differentially expressed; and in the 20-hydroxyecdysone (20E) metabolic pathway, CYP307A1, CYP314A1, and CYP18A1 are differentially expressed. In the SM, the expression levels of CYP307A1 and CYP314A1 are significantly increased, whereas the expression level of CYP18A1 is significantly decreased; in the SF, the expression levels of the above genes are opposite to that of the SM. Expression trends of RNA-seq is consistent with the expression level of qRT-PCR, and seven of them are highly correlated (R ≥ 0.610) and four are moderately correlated (0.588 ≥ R ≥ 0.542).


Assuntos
Regulação da Expressão Gênica/fisiologia , Hemípteros/genética , Proteínas de Insetos/genética , Hormônios Juvenis/genética , Metamorfose Biológica/genética , Animais , Feminino , Hemípteros/crescimento & desenvolvimento , Proteínas de Insetos/metabolismo , Hormônios Juvenis/metabolismo , Masculino , Ninfa/genética , Ninfa/crescimento & desenvolvimento
9.
Chemosphere ; 236: 124834, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31549672

RESUMO

Graphene oxide (GO) has become a topic of increasing concern for its environmental and health risks. However, the potential toxic effects of GO on wildlife remain limited. The present study chose the Xenopus laevis tadpole as a model to assess the thyroid endocrine disruption as well as the lipid metabolic disturbance of GO. Tadpoles at the 51 stage were exposed to GO (0, 0.01, 0.1, and 1 mg/L) for 21 days, when tadpoles were undergoing an extremely complicated phase of morphological changes and growth. GO treatment showed obvious developmental toxicity, such as shortened snout-to-vent length (SVL) and hind limb length (HLL), decreased body weight, and delayed developmental stage. Exposure to GO also induced obvious decreases in whole-body triiodothyronine (T3) and thyroxin (T4) concentrations. The mRNA expression of genes related to the hypothalamic-pituitary-thyroid (HPT) axis also changed significantly. Furthermore, we observed significant decline in the fatty acids and triglycerides (TGs) concomitantly with changes in the expression of genes involved in the synthesis and metabolism of lipids in GO exposure groups. In contrast, high-density lipoprotein (HDL) and total bile acid levels increased remarkably, but cholesterol and low-density lipoprotein (LDH) levels showed no obvious changes. Taken together, the results revealed for the first time that GO could induce thyroid endocrine disruption and produce obvious disturbance effect on lipid synthesis and metabolism.


Assuntos
Disruptores Endócrinos/toxicidade , Grafite/toxicidade , Metabolismo dos Lipídeos/efeitos dos fármacos , Xenopus laevis/metabolismo , Animais , Grafite/farmacologia , Larva/efeitos dos fármacos , Metamorfose Biológica/efeitos dos fármacos , Óxidos/farmacologia , Glândula Tireoide/efeitos dos fármacos , Hormônios Tireóideos/metabolismo , Tiroxina/metabolismo , Tri-Iodotironina/metabolismo , Xenopus laevis/crescimento & desenvolvimento
10.
Elife ; 82019 09 17.
Artigo em Inglês | MEDLINE | ID: mdl-31526475

RESUMO

The swimming larvae of many marine animals identify a location on the sea floor to undergo metamorphosis based on the presence of specific bacteria. Although this microbe-animal interaction is critical for the life cycles of diverse marine animals, what types of biochemical cues from bacteria that induce metamorphosis has been a mystery. Metamorphosis of larvae of the tubeworm Hydroides elegans is induced by arrays of phage tail-like contractile injection systems, which are released by the bacterium Pseudoalteromonas luteoviolacea. Here we identify the novel effector protein Mif1. By cryo-electron tomography imaging and functional assays, we observe Mif1 as cargo inside the tube lumen of the contractile injection system and show that the mif1 gene is required for inducing metamorphosis. Purified Mif1 is sufficient for triggering metamorphosis when electroporated into tubeworm larvae. Our results indicate that the delivery of protein effectors by contractile injection systems may orchestrate microbe-animal interactions in diverse contexts.


Assuntos
Proteínas de Bactérias/metabolismo , Interações entre Hospedeiro e Microrganismos , Metamorfose Biológica , Poliquetos/crescimento & desenvolvimento , Poliquetos/microbiologia , Pseudoalteromonas/metabolismo , Animais , Microscopia Crioeletrônica , Tomografia com Microscopia Eletrônica , Poliquetos/efeitos dos fármacos , Transporte Proteico
11.
Sci Total Environ ; 697: 134140, 2019 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-31476497

RESUMO

Organotin compounds are the ubiquitous environmental pollutants due to their wide industrial and agricultural applications and unexpected releasing into the environment, which show characteristic of endocrine disruptors to interfere with the synthesis, receptor binding or action of endogenous-hormones. Organotin pesticides (OTPs) are used in agriculture and may impact endocrine functions on organisms. Thyroid hormones (THs) play fundamental roles in regulating the basal metabolism and energy balance, while thyroid function can be impaired by environmental contaminants. Therefore, it is crucial to clarify the effects and mechanisms of OTPs on hypothalamus-pituitary-thyroid (HPT) axis. In this study, Xenopus laevis tadpoles at stage 51 were exposed to fentin hydroxide and fenbutatin oxide (0.04, 0.20 and 1.00 µg·L-1) for 21 days. It was found that both compounds caused inhibitory effects on metamorphic development of tadpoles (e.g., significant decrease in hindlimb length and retarding development). Triiodothyronine (T3) significantly decreased in tadpoles exposed to 0.20 µg/L and 1.00 µg/L of the two OTPs for 14 days or 21 days. The expressions of TH responsive genes trß, bteb and dio2 were down-regulated, while tshß and slc5a5 were up-regulated. Surface plasmon resonance (SPR) binding assays showed that fentin hydroxide had a moderate affinity to recombinant human thyroid hormone receptor ß but fenbutatin oxide did not have. Result of the SPR assay was highly consistent with the luciferase reporter gene assays that fentin hydroxide suppressed the relative luciferase activity in the presence of T3 while fenbutatin oxide did not, demonstrating fentin hydroxide but not fenbutatin oxide displayed an antagonistic activity against T3-TR complex mediated transcriptional activation. Overall, the findings elucidated the mechanisms induced by OTPs along HPT axis. These results highlighted the adverse influences of organotin pesticides on thyroid hormone- dependent development in vertebrates and the need for more comprehensive investigations of their potential ecological risks.


Assuntos
Disruptores Endócrinos/toxicidade , Metamorfose Biológica/efeitos dos fármacos , Compostos Orgânicos de Estanho/toxicidade , Praguicidas/toxicidade , Glândula Tireoide/efeitos dos fármacos , Animais , Larva , Glândula Tireoide/fisiologia , Hormônios Tireóideos , Poluentes Químicos da Água/toxicidade , Xenopus laevis
12.
Environ Monit Assess ; 191(10): 608, 2019 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-31485806

RESUMO

We assessed whether soil disturbance by agricultural activity influences the growth, development, and survival of individuals in the larval, metamorphic, and postmetamorphic stages of amphibians. Tadpoles of Pithecopus azureus (Cope, 1862) were reared in microcosms assembled with soil from two sites, a pristine site and a rice field. For 5 weeks, we recorded tadpole growth and development as well as physicochemical variable of the water: temperature, conductivity, dissolved oxygen, and pH. The results show that rice field soil produced a level of acidification in the water that influenced the growth and development rates of tadpoles. Tadpoles reared in rice soil had a significantly lower growth rate and body length, and during a specified period, the development rate of the tadpole was significantly lower than that of tadpoles in pristine soil. Overall, tadpoles in rice soil took 3 days longer to reach metamorphosis and 1 additional day to complete metamorphosis compared with tadpoles exposed to pristine soil. Our study shows that disturbed soils modify the physicochemical conditions of temporary ponds, impacting on the initial life stage of the anurans.


Assuntos
Agricultura , Anuros/fisiologia , Meio Ambiente , Solo/química , Animais , Anuros/crescimento & desenvolvimento , Concentração de Íons de Hidrogênio , Larva/crescimento & desenvolvimento , Traços de História de Vida , Metamorfose Biológica
13.
PLoS Biol ; 17(9): e3000378, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31479438

RESUMO

During terminal differentiation, most cells exit the cell cycle and enter into a prolonged or permanent G0 in which they are refractory to mitogenic signals. Entry into G0 is usually initiated through the repression of cell cycle gene expression by formation of a transcriptional repressor complex called dimerization partner (DP), retinoblastoma (RB)-like, E2F and MuvB (DREAM). However, when DREAM repressive function is compromised during terminal differentiation, additional unknown mechanisms act to stably repress cycling and ensure robust cell cycle exit. Here, we provide evidence that developmentally programmed, temporal changes in chromatin accessibility at a small subset of critical cell cycle genes act to enforce cell cycle exit during terminal differentiation in the Drosophila melanogaster wing. We show that during terminal differentiation, chromatin closes at a set of pupal wing enhancers for the key rate-limiting cell cycle regulators Cyclin E (cycE), E2F transcription factor 1 (e2f1), and string (stg). This closing coincides with wing cells entering a robust postmitotic state that is strongly refractory to cell cycle reactivation, and the regions that close contain known binding sites for effectors of mitogenic signaling pathways such as Yorkie and Notch. When cell cycle exit is genetically disrupted, chromatin accessibility at cell cycle genes remains unaffected, and the closing of distal enhancers at cycE, e2f1, and stg proceeds independent of the cell cycling status. Instead, disruption of cell cycle exit leads to changes in accessibility and expression of a subset of hormone-induced transcription factors involved in the progression of terminal differentiation. Our results uncover a mechanism that acts as a cell cycle-independent timer to limit the response to mitogenic signaling and aberrant cycling in terminally differentiating tissues. In addition, we provide a new molecular description of the cross talk between cell cycle exit and terminal differentiation during metamorphosis.


Assuntos
Ciclo Celular , Diferenciação Celular , Cromatina/metabolismo , Metamorfose Biológica , Asas de Animais/crescimento & desenvolvimento , Animais , Drosophila melanogaster , Regulação da Expressão Gênica no Desenvolvimento , Elementos Reguladores de Transcrição , Asas de Animais/ultraestrutura
14.
Cell Host Microbe ; 26(3): 412-425.e5, 2019 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-31492656

RESUMO

Surviving infection requires immune and repair mechanisms. Developing organisms face the additional challenge of integrating these mechanisms with tightly controlled developmental processes. The larval Drosophila midgut lacks dedicated intestinal stem cells. We show that, upon infection, larvae perform limited repair using adult midgut precursors (AMPs). AMPs differentiate in response to damage to generate new enterocytes, transiently depleting their pool. Developmental delay allows for AMP reconstitution, ensuring the completion of metamorphosis. Notch signaling is required for the differentiation of AMPs into the encasing, niche-like peripheral cells (PCs), but not to differentiate PCs into enterocytes. Dpp (TGF-ß) signaling is sufficient, but not necessary, to induce PC differentiation into enterocytes. Infection-induced JAK-STAT pathway is both required and sufficient for differentiation of AMPs and PCs into new enterocytes. Altogether, this work highlights the constraints imposed by development on an organism's response to infection and demonstrates the transient use of adult precursors for tissue repair.


Assuntos
Proteínas de Drosophila/metabolismo , Drosophila/crescimento & desenvolvimento , Drosophila/metabolismo , Trato Gastrointestinal/metabolismo , Larva/metabolismo , Animais , Diferenciação Celular , Modelos Animais de Doenças , Drosophila/microbiologia , Drosophila/fisiologia , Proteínas de Drosophila/genética , Enterócitos/metabolismo , Trato Gastrointestinal/imunologia , Trato Gastrointestinal/microbiologia , Trato Gastrointestinal/patologia , Infecções por Bactérias Gram-Negativas/metabolismo , Infecções por Bactérias Gram-Negativas/patologia , Janus Quinases/metabolismo , Larva/imunologia , Larva/microbiologia , Metamorfose Biológica , Pectobacterium carotovorum/patogenicidade , Fatores de Transcrição STAT/metabolismo , Transdução de Sinais/fisiologia , Células-Tronco/metabolismo , Fatores de Transcrição/metabolismo , Transcriptoma
15.
J Insect Physiol ; 117: 103917, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31381903

RESUMO

Microbial associations are widespread across the insects. In the olive fruit fly Bactrocera oleae (Diptera: Tephritidae), vertically transmitted gut symbionts contribute to larval development inside the olive host, and to adult nutrition. Nevertheless, their effect on behavioural decisions of adults is unknown. In this study, we show that symbiotic bacteria affect oviposition behaviour in B. oleae. We studied the effect of different fruits as hosts and different gut-bacteria as gut-symbionts on oviposition attempts and fly development in B. oleae. Untreated flies that had native gut-symbionts attempted oviposition significantly more times than axenic flies as well as flies treated with medfly-associated Pantoea or Klebsiella bacteria. Axenic flies provided with a diet containing the homogenized gut of symbiotic flies recovered the same number of oviposition attempts as their symbiotic counterparts. As for as the different hosts, green olives (unripe) and grapes were preferred while black olives (ripe) elicited the least number of oviposition attempts, with an interactive effect of host and bacterial treatments. It appears that both the host attributes and the native gut-symbionts drive oviposition preference towards green olives in B. oleae. Moreover, both bacterial treatments and hosts significantly affected the development of B. oleae larvae. Though grapes elicited as many oviposition attempts as green olives, they yielded no pupae. Taken together, our results suggest that the intimate association between B. oleae and their gut-microbes, extends beyond nutritional support to behaviour.


Assuntos
Oviposição , Tephritidae/microbiologia , Tephritidae/fisiologia , Animais , Feminino , Masculino , Metamorfose Biológica , Microbiota , Simbiose
16.
Ecotoxicol Environ Saf ; 183: 109461, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31377519

RESUMO

The present work investigated the changes in DNA methylation pattern of Tenebrio molitor mitochondria genome at different development stages, which was fed with polyurethane foam as a sole diet. Polyurethane foam could influence the global methylation levels in mitochondria DNA of Tenebrio molitor. Different leves of 5-methylcytosine appeared at CpG and non-CpG sites of Tenebrio molitor mtDNA while they were fed with polyurethane foam: 10 CpG and 49 non-CpG sites at larval stage, 4 CpG and 31 non-CpG sites at pupa stage, 7 CpG and 56 non-CpG sites at adult stage in general. Moreover, we observed the decreased levels of ATP generation with the mitochondria DNA methylation variation. The results demonstrated that mitochondria DNA gene could be methylated in response to environmental pollutants to modulate stage-specific functions. Moreover, mtDNA methylation of polyurethane-foam-feeding Tenebrio molitor existed discrepancy in the developmental stage. The tentative methylation mechanism of mtDNA might be that polyurethane foam induced oxidative stress and increased the permeability of mitochondrial membranes, which resulted in transmethylase entry into mitochondria.


Assuntos
DNA Mitocondrial/efeitos dos fármacos , Poluentes Ambientais/toxicidade , Epigênese Genética/efeitos dos fármacos , Metamorfose Biológica/efeitos dos fármacos , Poliuretanos/toxicidade , Tenebrio/efeitos dos fármacos , 5-Metilcitosina/metabolismo , Animais , Metilação de DNA/efeitos dos fármacos , Larva/efeitos dos fármacos , Larva/genética , Metamorfose Biológica/genética , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/genética , Mitocôndrias/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/genética , Pupa/efeitos dos fármacos , Pupa/genética , Tenebrio/genética , Tenebrio/crescimento & desenvolvimento
17.
Insect Biochem Mol Biol ; 112: 103206, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31425850

RESUMO

Wings are an indispensable structure in many insects for their foraging, courtship, escape from predators, and migration. Cuticular proteins are major components of the insect cuticle and wings, but there is limited information on how cuticular proteins may play an essential role in wing morphogenesis. We identified a wing-specific cuticular protein, LmACP7, which belongs to the RR-2 subfamily of CPR chitin-binding proteins in the migratory locust. LmACP7 was initially produced in epidermal cells and subsequently migrated to the exocuticle at the pre-ecdysial stage in adult wings. Depletion of LmACP7 transcripts by RNA interference markedly reduced its protein amounts, which consequently led to abnormal wing morphogenesis. The deformed wings were curved, wrinkled, and failed to fully expand. We further demonstrated that the deformation was caused by both severe damage of the endocuticle and death of the epidermal cells in the wings. Based on these data, we propose that LmACP7 not only serves as an essential structural protein in the wing but is also required for the integrity of wing epithelial cells. LmACP7 contributes to production of the wing endocuticle and to the morphogenesis of functional wings in the migratory locust.


Assuntos
Proteínas de Insetos/genética , Locusta migratoria/genética , Asas de Animais/crescimento & desenvolvimento , Animais , Quitina/metabolismo , Células Epidérmicas/metabolismo , Proteínas de Insetos/metabolismo , Locusta migratoria/crescimento & desenvolvimento , Metamorfose Biológica/genética , Morfogênese/genética , Ninfa/genética , Ninfa/crescimento & desenvolvimento , Interferência de RNA , Asas de Animais/anormalidades
18.
Mar Pollut Bull ; 146: 908-914, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31426235

RESUMO

Artificial light at night (ALAN) is a recently acknowledged form of anthropogenic pollution of growing concern to the biology and ecology of exposed organisms. Though ALAN can have detrimental effects on physiology and behaviour, we have little understanding of how marine organisms in coastal areas may be impacted. Here, we investigated the effects of ALAN exposure on coral reef fish larvae during the critical recruitment stage, encompassing settlement, metamorphosis, and post-settlement survival. We found that larvae avoided illuminated settlement habitats, however those living under ALAN conditions for 10 days post-settlement experienced changes in swimming behaviour and higher susceptibility to nocturnal predation. Although ALAN-exposed fish grew faster and heavier than control fish, they also experienced significantly higher mortality rates by the end of the experimental period. This is the first study on the ecological impacts of ALAN during the early life history of marine fish.


Assuntos
Peixes/fisiologia , Larva/efeitos da radiação , Luz/efeitos adversos , Animais , Ecossistema , Poluição Ambiental/efeitos adversos , Peixes/crescimento & desenvolvimento , Larva/crescimento & desenvolvimento , Larva/fisiologia , Metamorfose Biológica/efeitos da radiação , Comportamento Predatório/efeitos da radiação
19.
Chemosphere ; 235: 952-958, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31299708

RESUMO

Ecological risk of chemicals to aquatic-phase amphibians has historically been evaluated by comparing estimated environmental concentrations in surface water to surrogate toxicity data from fish species. Despite their obvious similarities, there are biological disparities among fish and amphibians that could affect their exposure and response to chemicals. Given the alarming decline in amphibians, in which anthropogenic pollutants play at least some role, investigating the risk of chemicals to amphibians is becoming increasingly important. Here, we evaluate relative sensitivity of fish and larval aquatic-phase amphibians to 45 different pesticides using existing data from three standardized toxicity test designs: (1) amphibian metamorphosis assay (AMA) with the African clawed frog (Xenopus laevis); (2) fish short-term reproduction assay (FSTRA) with the fathead minnow (Pimephales promelas); (3) fish early life stage test (ELS) with fathead minnows or rainbow trout (Oncorhynchus mykiss). The advantage of this dataset over previous work is that the underlying studies are consistent in exposure method, study duration, test species, endpoints measured, and number of concentrations tested. We found very strong positive relationships between fish and frog lowest adverse effect concentrations (LOAEC) for survival [Spearman's rank correlation (rs) = 0.88], body weight (rs = 0.86), and length (rs = 0.89) with only one out of 45 chemicals (propiconazole) exhibiting 100-folder greater sensitivity in frogs relative to fish. While our results suggest comparable toxicity for pesticides between fish and aquatic-phase amphibians under these test conditions, further research with a greater diversity of amphibians and exposure scenarios will help determine the relevance of these results across species and life stages.


Assuntos
Cyprinidae/embriologia , Metamorfose Biológica/efeitos dos fármacos , Oncorhynchus mykiss/embriologia , Praguicidas/toxicidade , Poluentes Químicos da Água/toxicidade , Xenopus laevis/embriologia , Animais , Ecologia , Larva/efeitos dos fármacos , Reprodução , Medição de Risco/métodos , Alimentos Marinhos
20.
Chemosphere ; 235: 885-899, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31284137

RESUMO

Harmful effects of triclosan (TCS) have been reported on several organisms; however, effects on early life stages of marine vertebrates are limited. Therefore, the objective of this work was to assess the effects of TCS during early development of the flatfish Solea senegalensis after initial characterization of cholinesterases (ChEs) and determination of selected biochemical markers baseline levels. Characterization of ChEs and determination of biochemical markers baseline levels of cholinergic activity, energy metabolism and oxidative stress were analysed in sole at 3 days after hatching (dah) and at the onset and end of metamorphosis. To assess TCS effects, fish were exposed during 96h to 30-500 µg L-1 TCS until 3 dah. Fish at 13 dah were exposed during 48h to 200-1,500 µg L-1 TCS and maintained until complete metamorphosis. Effects on survival, malformations, length, metamorphosis progression and biochemical markers were evaluated. The main ChE active form present in sole early life stages is acetylcholinesterase and baseline levels of oxidative stress and energy metabolism biomarkers changed according to fish developmental stage. Triclosan induced malformations (EC50 = 180 µg L-1 at 3 dah), decreased growth (95 µg L-1 at 3 dah; 548 µg L-1 at 24 dah) and affected metamorphosis progression (391 µg L-1 at 17 dah). Impairment of antioxidant system was observed, with TCS affecting catalase at the end of metamorphosis test, however, no oxidative damage on lipids was detected. Glutathione S-transferase was the most sensitive endpoint during early larval test (LOEC = 30 µg L-1). Exposure to TCS affected S. senegalensis at individual and sub-individual levels, both at early larval stage and during the critical period of metamorphosis.


Assuntos
Linguados/embriologia , Larva/efeitos dos fármacos , Metamorfose Biológica/efeitos dos fármacos , Triclosan/toxicidade , Acetilcolinesterase/metabolismo , Animais , Catalase/metabolismo , Colinesterases/metabolismo , Metabolismo Energético/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Triclosan/metabolismo
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