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1.
Arch Insect Biochem Physiol ; 106(4): e21783, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33719082

RESUMO

Vitamin C (VC) is an essential nutrient for many animals. However, whether insects, including Bombyx mori, can synthesize VC remains unclear. In this article, the optimized HPLC method was used to determine the content of l-ascorbic acid (AsA) in silkworm eggs, larvae and pupae, and the activity of l-gulono-1,4-lactone oxidase (GULO), a key enzyme in VC synthesis. The RNA interference method was used to determine the effect of the BmGulo-like gene on embryonic development and GULO activity in the pupal fat body. The AsA content increased significantly during E144 h-E168 h in the late embryonic stage and P48 h-P144 h in the middle-late pupal stage, in which exogenous VC was not ingested. Furthermore, the body AsA content in larvae fed VC-free feed also increased with larval stage. The GULO enzymatic activity was present in eggs and the fat bodies of larvae and pupae, even when the larvae were reared with fresh mulberry leaves. Moreover, the activity was higher in the later embryonic stages (E144 h-E168 h) and the early pupal stage (before P24 h). The GULO activity in the pupal fat body dramatically decreased when the screened BmGulo-like gene (BGIBMGA005735) was knocked down with small interfering RNA; in addition, the survival rate and hatching rate of eggs significantly decreased 21% and 44%, respectively, and embryonic development was delayed. Thus, Bombyx mori can synthesize AsA through the l-gulose pathway, albeit with low activity, and this synthesis ability varies with developmental stages.


Assuntos
Ácido Ascórbico/metabolismo , Bombyx/metabolismo , Animais , Bombyx/crescimento & desenvolvimento , Hexoses/metabolismo , Larva/crescimento & desenvolvimento , Larva/metabolismo , Pupa/crescimento & desenvolvimento , Pupa/metabolismo , Açúcares Ácidos/metabolismo
2.
PLoS One ; 15(12): e0244493, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33382763

RESUMO

The Chinese citrus fly, Bactrocera minax, is a notorious univoltine pest that causes damage to citrus. B. minax enters obligatory pupal diapause in each generation to resist harsh environmental conditions in winter. Despite the enormous efforts that have been made in the past decade, the understanding of pupal diapause of B. minax is currently still fragmentary. In this study, the 20-hydroxyecdysone solution and ethanol solvent was injected into newly-formed pupae to obtain non-diapause- (ND) and diapause-destined (D) pupae, respectively, and a comparative proteomics analysis between ND and D pupae was performed 1 and 15 d after injection. A total of 3,255 proteins were identified, of which 190 and 463 were found to be differentially abundant proteins (DAPs) in ND1 vs D1 and ND15 vs D15 comparisons, respectively. The reliability and accuracy of LFQ method was validated by qRT-PCR. Functional analyses of DAPs, including Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment, and protein-protein interaction (PPI) network construction, were conducted. The results revealed that the diapause program of B. minax is closely associated with several physiological activities, such as phosphorylation, chitin biosynthesis, autophagy, signaling pathways, endocytosis, skeletal muscle formation, protein metabolism, and core metabolic pathways of carbohydrate, amino acid, and lipid conversion. The findings of this study provide insights into diapause program of B. minax and lay a basis for further investigation into its underlying molecular mechanisms.


Assuntos
Diapausa de Inseto/fisiologia , Proteínas de Insetos/fisiologia , Mapas de Interação de Proteínas/fisiologia , Tephritidae/crescimento & desenvolvimento , Animais , Citrus/parasitologia , Diapausa de Inseto/efeitos dos fármacos , Ecdisterona/farmacologia , Proteínas de Insetos/análise , Doenças das Plantas/parasitologia , Doenças das Plantas/prevenção & controle , Mapeamento de Interação de Proteínas , Proteômica , Pupa/efeitos dos fármacos , Pupa/crescimento & desenvolvimento , Tephritidae/efeitos dos fármacos
3.
PLoS One ; 15(9): e0236653, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32956411

RESUMO

Symbiosis can facilitate the development of specialized organs in the host body to maintain relationships with beneficial microorganisms. To understand the developmental and genetic mechanisms by which such organs develop, it is critical to first investigate the morphology and developmental timing of these structures during the onset of host development. We utilized micro-computed tomography (µCT) to describe the morphology and development of mycangia, a specialized organ, in the Asian ambrosia beetle species Euwallacea validus which maintains a mutualistic relationship with the Ascomycete fungus, Fusarium oligoseptatum. We scanned animals in larval, pupal and adult life stages and identified that mycangia develop during the late pupal stage. Here we reconcile preliminary evidence and provide additional morphological data for a second paired set of structures, including the superior, medial mycangia and an inferior, lateral pair of pouch-like structures, in both late-stage pupae and adult female beetles. Furthermore, we report the possible development of rudimentary, or partially developed pairs of medial mycangia in adult male beetles which has never been reported for any male Xyleborini. Our results illustrate the validity of µCT in observing soft tissues and the complex nature of mycangia morphology and development.


Assuntos
Besouros/crescimento & desenvolvimento , Besouros/ultraestrutura , Animais , Besouros/anatomia & histologia , Feminino , Larva/anatomia & histologia , Larva/crescimento & desenvolvimento , Larva/ultraestrutura , Masculino , Pupa/anatomia & histologia , Pupa/crescimento & desenvolvimento , Pupa/ultraestrutura , Caracteres Sexuais , Microtomografia por Raio-X
4.
Ecotoxicol Environ Saf ; 204: 111034, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32758695

RESUMO

Trehalose is the major blood sugar in insects; it not only serves as an energy source but also plays important roles in physiological responses to adverse conditions. However, only a few studies have explored the effects of heavy metal exposure stress on trehalose metabolism in insects. Therefore, in this study, we examined the effects of cadmium stress on changes in trehalose metabolism in Aedes albopictus. Three concentrations of cadmium (0.005, 0.01, and 0.1 mg/L) were selected for evaluation of long-term stress in Ae. albopictus (from eggs to adults); Ae. albopictus in double-distilled water was used as the control group. The trehalose and glucose contents, trehalase activity, and trehalose metabolism-related gene expression were determined. The effects of long-term cadmium exposure on growth, development, and reproduction were also assessed. Trehalose contents were increased, whereas glucose contents and trehalase activity were decreased in Ae. albopictus following long-term exposure to low concentrations of cadmium compared with those in untreated individuals. Moreover, the expression of trehalose-6-phosphate synthase was upregulated, and that of trehalase was downregulated, indicating that Ae. albopictus may enhance trehalose synthesis to resist cadmium stress. Cadmium exposure also caused Ae. albopictus individuals to become smaller with a longer developmental duration, whereas both reproduction and hatching rates of the offspring were decreased compared with those in the control group. Our findings demonstrated that cadmium exposure affected the morphology, physiology, and biochemistry of Ae. albopictus. These findings also confirmed the role of trehalose in the response of Ae. albopictus to cadmium stress, providing insights into the effects of heavy metal stress on trehalose metabolism in an insect model.


Assuntos
Aedes/efeitos dos fármacos , Cádmio/efeitos adversos , Trealose/metabolismo , Poluentes Químicos da Água/efeitos adversos , Aedes/crescimento & desenvolvimento , Aedes/metabolismo , Animais , Feminino , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Larva/metabolismo , Óvulo/efeitos dos fármacos , Óvulo/crescimento & desenvolvimento , Óvulo/metabolismo , Pupa/efeitos dos fármacos , Pupa/crescimento & desenvolvimento , Pupa/metabolismo
5.
BMC Evol Biol ; 20(1): 79, 2020 06 29.
Artigo em Inglês | MEDLINE | ID: mdl-32600301

RESUMO

BACKGROUND: Metamorphosis remains one of the most complicated and poorly understood processes in insects. This is particularly so for the very dynamic transformations that take place within the pupal sheath of holometabolous insects. Only few studies address these transformations especially with regard to cranial structures of those holometabolous species where the larval and adult forms have a similar diet. It thus remains unclear to what extent the internal structures undergo histolysis and rebuilding. Here, the development of the brain and skeleto-muscular system of the head of Chrysopa pallens (Rambur, 1838) is studied. This species is a predator of aphids in the larval and adult stage. RESULTS: We used micro-computed-tomography (µ-CT) to study the transformations of the larval, prepupal and pupal head within the cocoon. We first assessed the morphological differences and similarities between the stages. We then determined the point in time when the compound eyes appear and describe the re-orientation of the head capsule which transforms the prognathous larva into a hypognathous adult. The internal head muscles are distinctly more slender in larvae than adults. In addition, the adults have a significantly larger brain which is likely needed for the processing of the signals obtained by the adults vastly expanded sensory organs that are presumably needed for dispersal and mating. Our study shows that the histolysis and modification of the inner muscles and skeletal elements take place within the prepupa. The central nervous system persists throughout metamorphosis but its morphology changes significantly. CONCLUSION: Our study reveals that not only the inner structures, but also the outer morphology continues to change after the final larval moult. The adult cuticle and internal structures form gradually within the cocoon. The histolysis and rebuilding begin with the skeletal elements and is followed by changes in the central nervous system before it concludes with modifications of the musculature. This order of events is likely ancestral for Holometabola because it is also known from Hymenoptera, Diptera, Mecoptera, and Coleoptera.


Assuntos
Evolução Biológica , Cabeça/anatomia & histologia , Insetos/anatomia & histologia , Insetos/crescimento & desenvolvimento , Metamorfose Biológica , Animais , Cabeça/diagnóstico por imagem , Imageamento Tridimensional , Larva/anatomia & histologia , Larva/crescimento & desenvolvimento , Músculos/anatomia & histologia , Pupa/anatomia & histologia , Pupa/crescimento & desenvolvimento , Tomografia Computadorizada por Raios X
6.
Arch Insect Biochem Physiol ; 105(1): e21726, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32681693

RESUMO

Eclosion hormone (EH) is an important neuropeptide that regulates growth and development. This study predicted the EH gene (HvEH) of Heortia vitessoides Moore (Lepidoptera: Crambidae) from the transcriptome database and its expression patterns were determined using quantitative real-time polymerase chain reaction. HvEH was expressed in all developmental stages and especially in the head area. RNA interference-mediated silencing of HvEH (2 µg/individual) with double-stranded HvEH RNA (dsHvEH) was achieved within 48 hr. Abnormal phenotypes appeared in the pupa and adult stages. dsHvEH injection suppressed pupation and eclosion rates. HvEH expression increased upon treatment with 20-hydroxyecdysone but decreased at extreme temperatures. These results suggest that HvEH plays an essential role in ecdysis and wing formation in H. vitessoides.


Assuntos
Hormônios de Inseto/genética , Proteínas de Insetos/genética , Muda/genética , Mariposas/genética , Interferência de RNA , Animais , Hormônios de Inseto/metabolismo , Proteínas de Insetos/metabolismo , Larva/genética , Larva/crescimento & desenvolvimento , Larva/metabolismo , Mariposas/crescimento & desenvolvimento , Mariposas/metabolismo , Filogenia , Pupa/genética , Pupa/crescimento & desenvolvimento , Pupa/metabolismo , Análise de Sequência de DNA
7.
J Vis Exp ; (160)2020 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-32568222

RESUMO

Within multicellular organisms, mature tissues and organs display high degrees of order in the spatial arrangements of their constituent cells. A remarkable example is given by sensory epithelia, where cells of the same or distinct identities are brought together via cell-cell adhesion showing highly organized planar patterns. Cells align to one another in the same direction and display equivalent polarity over large distances. This organization of the mature epithelia is established over the course of morphogenesis. To understand how the planar arrangement of the mature epithelia is achieved, it is crucial to track cell orientation and growth dynamics with high spatiotemporal fidelity during development in vivo. Robust analytical tools are also essential to identify and characterize local-to-global transitions. The Drosophila pupa is an ideal system to evaluate oriented cell shape changes underlying epithelial morphogenesis. The pupal developing epithelium constitutes the external surface of the immobile body, allowing long-term imaging of intact animals. The protocol described here is designed to image and analyze cell behaviors at both global and local levels in the pupal abdominal epidermis as it grows. The methodology described can be easily adapted to the imaging of cell behaviors at other developmental stages, tissues, subcellular structures, or model organisms.


Assuntos
Drosophila/crescimento & desenvolvimento , Imagem Molecular , Pupa/crescimento & desenvolvimento , Animais , Forma Celular , Drosophila/citologia , Células Epidérmicas/citologia , Epitélio/crescimento & desenvolvimento , Morfogênese , Pupa/citologia
8.
Arch Insect Biochem Physiol ; 105(1): e21720, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32557681

RESUMO

The large-conductance calcium-activated potassium channel (BKCa ) plays an important role in the regulation of insect neural circuits and locomotion, and thus is a potential target of insecticides. In this study, iberiotoxin, an inhibitor of BKCa , was found to prolong the anesthetic time of ethyl acetate on Plutella xylostella larvae. Therefore, the coding sequence of slowpoke gene coding the alpha subunit of BKCa was cloned to investigate the function of this channel in P. xylostella, and the gene expression profile in the developmental stages and tissues was also characterized. The total length of pxslo DNA was more than 19.9 kb, which harbored four alternative splicing sites (ASP-A, ASP-C, ASP-E, and ASP-G), and the coding sequence of pxslo with the highest frequency of splicing (GenBank ID: MN938456) was 3,405 base pair. The characterized PxSlo protein contained conserved domains previously identified in other insects. Quantitative reverse transcription-polymerase chain reaction analysis showed that pxslo was expressed in all the developmental stages of P. xylostella, with the highest level in adults. In the larval stage, pxslo was mainly expressed in the head and epidermis, while a limited protein was expressed in the midgut. In the adult stage, pxslo was highly expressed in the head, followed by in the ovarian tubule, and was not expressed in the testis or wings. These results suggest that BKCa plays an important physiological role in P. xylostella and provides useful information for the functional study and screening of BKCa inhibitors.


Assuntos
Proteínas de Insetos/genética , Canais de Potássio Ativados por Cálcio de Condutância Alta/genética , Mariposas/genética , Transcriptoma , Sequência de Aminoácidos , Animais , Proteínas de Insetos/química , Proteínas de Insetos/metabolismo , Canais de Potássio Ativados por Cálcio de Condutância Alta/química , Canais de Potássio Ativados por Cálcio de Condutância Alta/metabolismo , Larva/genética , Larva/crescimento & desenvolvimento , Mariposas/crescimento & desenvolvimento , Mariposas/metabolismo , Óvulo/crescimento & desenvolvimento , Pupa/genética , Pupa/crescimento & desenvolvimento , Alinhamento de Sequência
9.
Arch Insect Biochem Physiol ; 105(1): e21718, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32515853

RESUMO

The autophagy process involves a series of autophagy-related (Atg) proteins, which are conserved in eukaryotes. ULK1/Atg1-ATG13/Atg13 is the core protein complex for autophagy initiation in response to nutrient and hormone signaling. However, how Atg13 is regulated to participate in autophagy is unclear in insects. Here in Bombyx mori, the variation of BmAtg13 was correlated with autophagy induced by steroid hormone 20-hydroxyecdysone (20E) or starvation. Developmental profiles from feeding to prepupal stage revealed that there were two bands of BmAtg13 protein detected by western blot analysis, therein the upper band was intensively decreased, while the lower band was significantly increased which was in accordance with its mRNA variation; and immunofluorescent staining indicated that BmAtg13 was nucleocytoplasmic translocated during larval-pupal metamorphosis when autophagy was dramatically induced. BmAtg13 knockdown and overexpression both inhibits autophagy. Besides, 20E treatment-induced BmAtg13 gene expression, while blocking 20E signaling transduction by knockdown of BmUsp reduced both gene expression and protein level of BmAtg13. These results reveal that BmAtg13 is required for 20E- and starvation-induced autophagy in B. mori, which provides the foundation for further related studies.


Assuntos
Proteínas Relacionadas à Autofagia/genética , Autofagia/genética , Bombyx/fisiologia , Proteínas de Insetos/genética , Animais , Proteínas Relacionadas à Autofagia/metabolismo , Bombyx/genética , Bombyx/crescimento & desenvolvimento , Ecdisterona/metabolismo , Privação de Alimentos , Proteínas de Insetos/metabolismo , Larva/crescimento & desenvolvimento , Larva/fisiologia , Metamorfose Biológica/fisiologia , Pupa/crescimento & desenvolvimento , Pupa/fisiologia
10.
J Insect Sci ; 20(3)2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32478839

RESUMO

The spotted wing drosophila, Drosophila suzukii Matsumura, which is widely spread in the main soft-skinned fruits production areas in China, presents a threat to importing countries. In order to develop a phytosanitary cold treatment measure for preventing the movement of this drosophila fly, cold tolerance of six immature life stages of D. suzukii was compared followed by time-mortality and large-scale confirmatory tests on the most tolerant stage in grape fruit. Egg was defined as the most cold-tolerant stage by comparing the mortality of all the immature stages (egg, first, second, and third instars, early and late pupa) treated at 0 and 2°C. The minimal lethal time (LT) for 99.9968% mortality (95% confidence level [CL]) estimated by the probit model was 10.47 d at 0°C and 11.92 d at 2°C, respectively. Hence, 11 d (at 0°C) and 12 d (at 2°C) were chosen as the target time to conduct the confirmatory tests. No survivors were found among the estimated 50,385 and 57,366 treated eggs, which resulted in the efficacy of 99.9941 and 99.9948% mortality (95% CL) at 0 and 2°C, respectively. Our study suggests a technical basis for cold disinfestation on D. suzukii in cage-infested Chinese 'Red Globe' (Vitis vinifera L.) grape, which could provide flexible phytosanitary treatment for control of D. suzukii in the international trade of grape.


Assuntos
Temperatura Baixa , Drosophila/fisiologia , Frutas , Controle de Insetos/métodos , Vitis , Animais , China , Drosophila/crescimento & desenvolvimento , Larva/crescimento & desenvolvimento , Larva/fisiologia , Óvulo/crescimento & desenvolvimento , Óvulo/fisiologia , Pupa/crescimento & desenvolvimento , Pupa/fisiologia
11.
J Insect Sci ; 20(3)2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32365175

RESUMO

Six candidate sHSP genes were identified from the Glyphodes pyloalis transcriptome. All sHSP genes included full-length open reading frames and shared high similarity with the sequences of other lepidopteran species. These sHSP genes encoded 175-191 amino acid residues, and the predicted proteins had a molecular weight from 19.5 to 21.8 kDa. All GpsHSPs were expressed at lower levels at larval stages. All GpsHSPs were expressed at higher levels at diapaused, prepupal, or pupal stages, suggesting that sHSPs may be involved in metamorphosis in G. pyloalis. In addition to the developmental stage, extreme temperatures can induce variations in the expression of sHSPs genes. All GpsHSPs were significantly upregulated in larvae following exposure to heat shock, except GpHSP21.4 which downregulated at 4 h following exposure to the cold shock treatment. Furthermore, Starvation influenced the expression patterns of GpsHSPs as a function of the duration of food deprivation. Four GpsHSPs increased their expression with time of starvation until reaching to the peak level at 6 d of starvation. Finally, parasitism by the endoparasitoid Aulacocentrum confusum He et van Achterberg (Hymenoptera: Braconidae)-induced fluctuations in the expression of all GpsHSPs, and the expression varied with time after parasitization. Our results from this study strongly suggest functional differentiation within the sHSPs subfamily in G. pyloalis. The present study would provide further insight into the roles of sHSPs in G. pyloalis and novel avenues for promoting integrated management of this pest.


Assuntos
Proteínas de Choque Térmico Pequenas/genética , Proteínas de Insetos/genética , Mariposas/genética , Transcriptoma , Sequência de Aminoácidos , Animais , Feminino , Proteínas de Choque Térmico Pequenas/química , Proteínas de Choque Térmico Pequenas/metabolismo , Proteínas de Insetos/química , Proteínas de Insetos/metabolismo , Larva/crescimento & desenvolvimento , Larva/metabolismo , Masculino , Mariposas/crescimento & desenvolvimento , Mariposas/metabolismo , Filogenia , Pupa/crescimento & desenvolvimento , Pupa/metabolismo , Alinhamento de Sequência
12.
Ecotoxicology ; 29(7): 1052-1061, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32448953

RESUMO

The combined use of chemicals and biological control is not always a successful strategy owing to the potential side effects on biocontrol agents. Lethal and sublethal effects of three commonly used insecticides were assessed on adult and immature stages of the egg parasitoid Trichogramma brassicae Bezdenko (Hymenoptera: Trichogrammatidae). Recommended field concentrations of chlorantraniliprole, phosalone and spinosad caused mortality on preimaginal stages by 24, 87, and 98%, respectively. Lethal effects on parasitoid adults exposed to the insecticide dry residues were estimated as median lethal concentrations (LC50) that were 13.28, 0.25, and 0.03 µg a.i. ml-1 for chlorantraniliprole, phosalone, and spinosad, respectively. The effect of a low lethal concentration (LC30) of the compounds was evaluated on various adult biological traits, such as longevity, fecundity, emergence rate and other life table parameters. All compounds caused detrimental effects on all the estimated demographical indexes. Chlorantraniliprole affected the net reproductive rate, mean generation time and doubling time in comparison to the control; while, phosalone and spinosad adversely affected all assessed parameters. Phosalone and spinosad significantly reduced gross reproductive rate, net reproductive rate, intrinsic rate of increase, finite rate of increase, mean generation time and doubling time and reduced longevity, fecundity, emergence rate related to other biological parameters in comparison with control. The results suggest that all compounds are not fully compatible with the activity of T. brassicae, and that the inclusion of chlorantraniprole, spinosad and phosalone into Integrated Pest Management (IPM) involving this parasitoid has to be avoided. Nevertheless, further studies in open field conditions and on a multiple generation scale are necessary for providing a more definitive conclusion on the IPM suitability of the three tested insectcides.


Assuntos
Inseticidas/toxicidade , Macrolídeos/toxicidade , Compostos Organotiofosforados/toxicidade , Resíduos de Praguicidas/toxicidade , Vespas/efeitos dos fármacos , ortoaminobenzoatos/toxicidade , Animais , Combinação de Medicamentos , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Larva/parasitologia , Mariposas/crescimento & desenvolvimento , Mariposas/parasitologia , Óvulo/efeitos dos fármacos , Óvulo/crescimento & desenvolvimento , Óvulo/parasitologia , Pupa/efeitos dos fármacos , Pupa/crescimento & desenvolvimento , Pupa/parasitologia
13.
Gene ; 751: 144779, 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-32428697

RESUMO

In insects, nuclear receptors (NRs) including EcR (NR1H1), USP (NR2B4), E75 (NR1D3), HR3 (NR1F), HR4 (NR6) and FTZ-F1 (NR5A3) mediate the 20-hydroxyecdysone (20E) signaling cascade to play a critical role during larval metamorphosis. In this present paper, we focused on hormone receptor 38 (HR38) in Leptinotarsa decemlineata, the only insect homolog of the NR4A subclass. RNA interference (RNAi) of LdHR38 in the penultimate (third) instar larvae reduced the expression of an ecdysteroidogenesis gene and declined the titer of 20E. Knockdown of LdHR38 intensified the expression of LdUSP, LdE75, LdE74, LdE93, LdBroad and LdHR3, whereas repressed the transcription of LdFTZ-F1. Disruption of 20E signaling inhibited chitin biosynthesis in the larval cuticle. Approximately 25% of the LdHR38 RNAi larvae died, around 40% of the resultant larvae remained as prepupae or become deformed pupae. The body surface of the HR38 depleted abnormal prepupae and pupae looked wet, just like the cuticle being covered with a layer of liquid. Moreover, the increase of larval mortality, and the impairment of pupation and emergence exhibited dose-dependent manners. Furthermore, silencing LdHR38 at the final (fourth) instar caused similar but less severe impairment of pupation. Dietary supplement with 20E for the third instar larvae did not rescue the high larval death and only slightly alleviated the low pupation rate in the LdHR38 RNAi hypomorphs. Accordingly, we propose that HR38 is necessary for tune of ecdysteroidogenesis and for mediation of 20E signaling during metamorphosis in L. decemlineata.


Assuntos
Besouros/crescimento & desenvolvimento , Proteínas de Insetos/fisiologia , Metamorfose Biológica , Receptores Citoplasmáticos e Nucleares/fisiologia , Animais , Quitina/biossíntese , Besouros/genética , Besouros/metabolismo , Ecdisterona/fisiologia , Proteínas de Insetos/antagonistas & inibidores , Proteínas de Insetos/genética , Larva/genética , Larva/crescimento & desenvolvimento , Larva/metabolismo , Pupa/genética , Pupa/crescimento & desenvolvimento , Pupa/metabolismo , Interferência de RNA , Receptores Citoplasmáticos e Nucleares/antagonistas & inibidores , Receptores Citoplasmáticos e Nucleares/genética , Transdução de Sinais
14.
J Insect Sci ; 20(3)2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32396202

RESUMO

A large number of ecdysteroid-regulated 16 kDa proteins (ESR16s) of insects have been isolated and annotated in GenBank; however, knowledge on insect ESR16s remain limited. In the present study, we characterized an ecdysteroid-regulated 16 kDa protein gene isolated in Chinese oak silkworm, Antheraea pernyi Guérin-Méneville ('ApESR16' in the following), an important silk-producing and edible insect. The obtained cDNA sequence of ApESR16 is 1,049 bp, harboring an open reading frame of 441 bp that encodes a polypeptide of 146 amino acids. CD-search revealed that ApESR16 contains the putative cholesterol/lipid binding sites on conserved domain Npc2_like (Niemann-Pick type C-2) belonging to the MD-2-related lipid-recognition superfamily. Sequence comparison revealed that ApESR16 exhibits 51-57% identity to ESR16s of lepidopteran insects, 36-41% identity to ESR16 or NPC2a of nonlepidopteran insects, and 28-32% identity to NPC2a of vertebrates, indicating a high sequence divergence during the evolution of animals. Phylogenetic analysis found that the used sequences were divided into two groups corresponding to vertebrates and invertebrates, and the used insect sequences were also well clustered according to their families. The A. pernyi ESR16 mRNA is expressed during all four developmental stages and in all tested tissues. Injection of 20-hydroxyecdysone (20-E) into A. pernyi diapausing pupae triggering diapause termination induced upregulation of ESR16 mRNA compared to the diapausing pupae, with the highest expression level at day 2 in the ovaries but day 12 in the fat body. Our results suggested that ApESR16 might be a diapause-related gene and plays a vital role in the pupal diapause of A. pernyi.


Assuntos
Ecdisteroides/metabolismo , Regulação da Expressão Gênica , Proteínas de Insetos/genética , Mariposas/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Feminino , Proteínas de Insetos/química , Proteínas de Insetos/metabolismo , Masculino , Mariposas/crescimento & desenvolvimento , Mariposas/metabolismo , Filogenia , Pupa/crescimento & desenvolvimento , Pupa/metabolismo , Alinhamento de Sequência
15.
Biochim Biophys Acta Gene Regul Mech ; 1863(8): 194576, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32389826

RESUMO

Juvenile hormones (JH) and ecdysone coordinately regulate metamorphosis in Aedes aegypti. We studied the function of an epigenetic regulator and multifunctional transactivator, CREB binding protein (CBP) in A. aegypti. RNAi-mediated knockdown of CBP in Ae. aegypti larvae resulted in suppression of JH primary response gene, Krüppel-homolog 1 (Kr-h1), and induction of primary ecdysone response gene, E93, resulting in multiple effects including early metamorphosis, larval-pupal intermediate formation, mortality and inhibition of compound eye development. RNA sequencing identified hundreds of genes, including JH and ecdysone response genes regulated by CBP. In the presence of JH, CBP upregulates Kr-h1 by acetylating core histones at the Kr-h1 promoter and facilitating the recruitment of JH receptor and other proteins. CBP suppresses metamorphosis regulators, EcR-A, USP-A, BR-C, and E93 through the upregulation of Kr-h1 and E75A. CBP regulates the expression of core eye specification genes including those involved in TGF-ß and EGFR signaling. These studies demonstrate that CBP is an essential player in JH and 20E action and regulates metamorphosis and compound eye development in Ae. aegypti.


Assuntos
Aedes/metabolismo , Proteína de Ligação a CREB/metabolismo , Olho/crescimento & desenvolvimento , Metamorfose Biológica/fisiologia , Organogênese/fisiologia , Aedes/genética , Animais , Proteína de Ligação a CREB/genética , Proteínas de Ligação a DNA/metabolismo , Proteínas de Drosophila , Ecdisona/genética , Ecdisona/metabolismo , Ecdisona/farmacologia , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Histonas/metabolismo , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Hormônios Juvenis/metabolismo , Hormônios Juvenis/farmacologia , Fatores de Transcrição Kruppel-Like/genética , Fatores de Transcrição Kruppel-Like/metabolismo , Larva , Organogênese/efeitos dos fármacos , Organogênese/genética , Regiões Promotoras Genéticas , Pupa/crescimento & desenvolvimento , Transdução de Sinais , Fatores de Transcrição/metabolismo , Febre Amarela/genética
16.
J Insect Sci ; 20(3)2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32458990

RESUMO

Survival and parasitism activity of Trichopria drosophilae Perkins adults, a cosmopolitan parasitoid of Drosophila spp., were studied under laboratory conditions using five constant temperatures at the lower range known for this enemy, from 4 to 20°C in 4°C increments. Drosophila suzukii Matsumura, an invasive pest of small fruits, was used as a host. Commercially available adult parasitoids were provided with 1) food and D. suzukii pupae; 2) food and no D. suzukii pupae; 3) no food and no pupae. The results show that adult females of T. drosophilae lived longer than males, and both generally benefitted from food supply. The highest level of survival was observed between 8 and 12°C for fed insects, irrespective of whether they were offered host pupae or not. The absence of food led to the highest mortality, but the parasitoid demonstrated considerably resistance to prolonged starvation. Successful parasitism increased steadily with temperature and reached the highest value at 20°C. Conversely, D. suzukii emergence rate was high after exposure of pupae to parasitoids at 4°C, while pupal mortality increased strongly with temperature until 12°C. The findings indicate that T. drosophilae is well adapted to the relatively cold conditions experienced in early spring and in autumn or at high elevations, when the host pupae could be largely available. The long lifespan of the adults and the ability to parasitize the host at low temperature make T. drosophilae potentially useful for the biocontrol of D. suzukii.


Assuntos
Drosophila/parasitologia , Interações Hospedeiro-Parasita , Controle de Insetos , Controle Biológico de Vetores , Vespas/fisiologia , Animais , Temperatura Baixa , Drosophila/crescimento & desenvolvimento , Feminino , Masculino , Pupa/crescimento & desenvolvimento , Pupa/parasitologia , Estações do Ano , Fatores Sexuais , Vespas/crescimento & desenvolvimento
17.
Sci Rep ; 10(1): 7077, 2020 04 27.
Artigo em Inglês | MEDLINE | ID: mdl-32341495

RESUMO

Neonicotinoid insecticides are associated with a decline in the diversity and distribution of bees and wasps (Hymenoptera: Aculeata). The effects of neonicotinoids on the metamorphosis of aculeates have never been addressed in detail; however, recent evidence suggests that neonicotinoids induce wing abnormalities. We hypothesized that the metamorphosis success of bees and wasps differs in response to contact exposure to field-realistic concentrations of neonicotinoid insecticides or in response to combined exposure to neonicotinoid insecticides and benzimidazole fungicides. We treated prepupae of the model crabronid wasp Pemphredon fabricii with field-realistic concentrations of four neonicotinoids, acetamiprid, imidacloprid, thiacloprid and thiamethoxam, and/or with the benzimidazole fungicide thiabendazole. Treatment with acetamiprid or imidacloprid decreased the pupation rates to only 39% and 32%, respectively. Treatment with thiacloprid or thiamethoxam did not affect the pupation rate when applied alone, but the subsequent treatment of thiacloprid- or thiamethoxam-treated prepupae with thiabendazole led to significant decreases in pupation rates. A high concentration of acetamiprid, which severely affected the pupation rates, had moderate effects on metamorphosis into adults, resulting in 53% metamorphosis success (as opposed to 95% metamorphosis success in the water-treated group). However, imidacloprid or thiamethoxam treatment resulted in only 5%-10% metamorphosis success into adults. Overall survival decreased in response to treatment with any of the neonicotinoids or benzimidazoles or their combinations, with extremely low survival (<2%) following combined treatment with imidacloprid and thiabendazole or thiamethoxam and thiabendazole. In conclusion, neonicotinoids alter insect metamorphosis success, which can be further potentiated by their combination with other agrochemicals, such as benzimidazoles.


Assuntos
Inseticidas/farmacologia , Metamorfose Biológica/efeitos dos fármacos , Neonicotinoides/farmacologia , Vespas/crescimento & desenvolvimento , Animais , Pupa/crescimento & desenvolvimento
18.
Int J Mol Sci ; 21(7)2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32244803

RESUMO

Chitin deacetylases (CDAs) are chitin-modifying enzymes known to play vital roles in insect metamorphosis and development. In this study, we identified and characterized a chitin deacetylase 1 gene (LsCDA1) from the cigarette beetle Lasioderma serricorne. LsCDA1 contains a 1614 bp open reading frame encoding a protein of 537 amino acids that includes domain structures typical of CDAs. LsCDA1 was mainly expressed in the late larval and late pupal stages. In larval tissues, the highest level of LsCDA1 was detected in the integument. The expression of LsCDA1 was induced by 20-hydroxyecdysone (20E) in vivo, and it was significantly suppressed by knocking down the expression of ecdysteroidogenesis genes and 20E signaling genes. RNA interference (RNAi)-aided silencing of LsCDA1 in fifth-instar larvae prevented the larval-pupal molt and caused 75% larval mortality. In the late pupal stage, depletion of LsCDA1 resulted in the inhibition of pupal growth and wing abnormalities, and the expression levels of four wing development-related genes (LsDY, LsWG, LsVG, and LsAP) were dramatically decreased. Meanwhile, the chitin contents of LsCDA1 RNAi beetles were significantly reduced, and expressions of three chitin synthesis pathway genes (LsTRE1, LsUAP1, and LsCHS1) were greatly decreased. The results suggest that LsCDA1 is indispensable for larval-pupal and pupal-adult molts, and that it is a potential target for the RNAi-based control of L. serricorne.


Assuntos
Amidoidrolases/genética , Besouros/genética , Proteínas de Insetos/genética , Metamorfose Biológica/genética , Muda/genética , Amidoidrolases/classificação , Amidoidrolases/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Quitina/metabolismo , Besouros/enzimologia , Besouros/crescimento & desenvolvimento , Ecdisterona/farmacologia , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Proteínas de Insetos/metabolismo , Larva/enzimologia , Larva/genética , Larva/crescimento & desenvolvimento , Filogenia , Pupa/enzimologia , Pupa/genética , Pupa/crescimento & desenvolvimento , Interferência de RNA , Asas de Animais/anormalidades , Asas de Animais/metabolismo
19.
PLoS One ; 15(4): e0231451, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32282855

RESUMO

Insect molting hormone (ecdysteroids) and juvenile hormone regulate molting and metamorphic events in a variety of insect species. Mealybugs undergo sexually dimorphic metamorphosis: males develop into winged adults through non-feeding, pupa-like stages called prepupa and pupa, while females emerge as neotenic wingless adults. We previously demonstrated, in the Japanese mealybug Planococcus kraunhiae (Kuwana), that the juvenile hormone titer is higher in males than in females at the end of the juvenile stage, which suggests that juvenile hormone may regulate male-specific adult morphogenesis. Here, we examined the involvement of ecdysteroids in sexually dimorphic metamorphosis. To estimate ecdysteroid titers, quantitative RT-PCR analyses of four Halloween genes encoding for cytochrome P450 monooxygenases in ecdysteroid biosynthesis, i.e., spook, disembodied, shadow and shade, were performed. Overall, their expression levels peaked before each nymphal molt. Transcript levels of spook, disembodied and shadow, genes that catalyze the steps in ecdysteroid biosynthesis in the prothoracic gland, were higher in males from the middle of the second nymphal instar to adult emergence. In contrast, the expression of shade, which was reported to be involved in the conversion of ecdysone into 20-hydroxyecdysone in peripheral tissues, was similar between males and females. These results suggest that ecdysteroid biosynthesis in the prothoracic gland is more active in males than in females, although the final conversion into 20-hydroxyecdysone occurs at similar levels in both sexes. Moreover, expression profiles of ecdysone response genes, ecdysone receptor and ecdysone-induced protein 75B, were also analyzed. Based on these expression profiles, we propose that the changes in ecdysteroid titer differ between males and females, and that high ecdysteroid titer is essential for directing male adult development.


Assuntos
Ecdisona/genética , Ecdisteroides/genética , Proteínas de Insetos/genética , Insetos/genética , Animais , Sistema Enzimático do Citocromo P-450/genética , Ecdisterona/genética , Feminino , Regulação da Expressão Gênica no Desenvolvimento/genética , Insetos/crescimento & desenvolvimento , Hormônios Juvenis/genética , Larva/genética , Larva/crescimento & desenvolvimento , Masculino , Metamorfose Biológica/genética , Morfogênese/genética , Pupa/genética , Pupa/crescimento & desenvolvimento , Caracteres Sexuais , Asas de Animais/crescimento & desenvolvimento
20.
Arch Insect Biochem Physiol ; 104(2): e21675, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32285519

RESUMO

The Drosophila inner photoreceptors R7 and R8 are responsible for color vision and their differentiation starts at the third instar larval stage. Only a handful of genes with R7 or R8-cell-specific expression are known. We performed an enhancer-trap screen using a novel piggyBac transposable element, pBGay, carrying a Gal4 sequence under the control of the P promoter to identify novel genes expressed specifically in R7 or R8 cells. From this screen, three lines were analyzed in detail: piggyBacAC109 and piggyBacAC783 are expressed in R8 cells and piggyBacAC887 is expressed in R7 cells at the third instar larval stage and pupal stages. Molecular analysis showed that the piggyBac elements were inserted into the first intron of CG14160 and CG7985 genes and the second intron of unzipped. We show the expression pattern in the developing eye imaginal disc, pupal retina as well as the adult retina. The photoreceptor-specific expression of these genes is reported for the first time and we propose that these lines are useful tools for studying the development of the visual system.


Assuntos
Elementos de DNA Transponíveis/genética , Proteínas de Drosophila/genética , Drosophila/genética , Células Fotorreceptoras de Invertebrados/metabolismo , Fatores de Transcrição/genética , Animais , Diferenciação Celular/genética , Drosophila/crescimento & desenvolvimento , Drosophila/metabolismo , Proteínas de Drosophila/metabolismo , Larva/genética , Larva/crescimento & desenvolvimento , Larva/metabolismo , Pupa/crescimento & desenvolvimento , Pupa/metabolismo , Fatores de Transcrição/metabolismo
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