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1.
J Agric Food Chem ; 68(4): 982-988, 2020 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-31909997

RESUMO

Cycloxaprid (CYC) is effective in the control of hemipteran pests, but its bioactivity against lepidopteran pests is still unclear. Here, the bioactivity of CYC against lepidopteran pests was found to be much worse than that against hemipteran insects. To reveal the mechanism, the transcriptomes of CYC-treated and untreated Ostrinia furnacalis larvae were compared. Among the top 20 differentially expressed genes, 11 encode proteins involved in cuticle formation, while only one encodes a detoxifying enzyme. Thus, the cuticle appears to be important for the insensitivity of O. furnacalis to CYC. A pretreatment of O. furnacalis larvae with methoprene enhanced the bioactivity of CYC by 1.12-fold. Moreover, mixtures of CYC with graphene oxide increased the bioactivity of CYC by 1.88-fold. Because lepidopteran and hemipteran insects often harm crops at the same time, the work can help make full use of CYC and reduce the environmental impacts of using multiple pesticides.


Assuntos
Compostos Heterocíclicos com 3 Anéis/química , Compostos Heterocíclicos com 3 Anéis/farmacologia , Inseticidas/química , Inseticidas/farmacologia , Mariposas/efeitos dos fármacos , Piridinas/química , Piridinas/farmacologia , Sequência de Aminoácidos , Animais , Proteínas de Insetos/química , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Estrutura Molecular , Mariposas/química , Mariposas/genética , Mariposas/crescimento & desenvolvimento , Alinhamento de Sequência
2.
J Insect Sci ; 20(1)2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31925425

RESUMO

Diaphania caesalis (Walker) is an important boring insect mainly distributed in subtropical and tropical areas and attacked tropical woody grain crops, such as starchy plants of Artocarpus. Quantitative real-time polymerase chain reaction (qRT-PCR) is a powerful approach for investigating target genes expression profiles at the transcriptional level. However, the identification and selection of internal reference genes, which is often overlooked, is the most vital step before the analysis of target gene expression by qRT-PCR. So far, the reliable internal reference genes under a certain condition of D. caesalis have not been investigated. Therefore, this study evaluated the expression stability of eight candidate reference genes including ACT, ß-TUB, GAPDH, G6PDH, RPS3a, RPL13a, EF1α, and EIF4A in different developmental stages, tissues and sexes using geNorm, NormFinder and BestKeeper algorithms. To verify the stability of the recommended internal reference genes, the expression levels of DcaeOBP5 were analyzed under different treatment conditions. The results indicated that ACT, RPL13a, ß-TUB, RPS3a, and EF1α were identified as the most stable reference genes for further studies on target gene expression involving different developmental stages of D. caesalis. And ACT and EIF4A were recommended as stable reference genes for different tissues. Furthermore, ACT, EF1α, and RPS3a were ranked as the best reference genes in different sexes based on three algorithms. Our research represents the critical first step to normalize qRT-PCR data and ensure the accuracy of expression of target genes involved in phylogenetic and physiological mechanism at the transcriptional level in D. caesalia.


Assuntos
Expressão Gênica , Genes de Insetos , Mariposas/genética , Animais , Perfilação da Expressão Gênica , Larva/genética , Larva/crescimento & desenvolvimento , Mariposas/crescimento & desenvolvimento , Óvulo/crescimento & desenvolvimento , Pupa/genética , Pupa/crescimento & desenvolvimento , Reação em Cadeia da Polimerase em Tempo Real
3.
J Insect Sci ; 20(1)2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31899494

RESUMO

Mamestra brassicae L. is an important, regionally migratory pest of vegetable crops in Europe and Asia. Its migratory activity contributes significantly to population outbreaks, causing severe crop yield losses. Because an in-depth understanding of flight performance is key to revealing migratory patterns, here we used a computer-linked flight mill and stroboscope to study the flight ability and wingbeat frequency (WBF) of M. brassicae in relation to sex, age, temperature, and relative humidity (RH). The results showed that age significantly affected the flight ability and WBF of M. brassicae, and 3-d-old individuals performed the strongest performance (total flight distance: 45.6 ± 2.5 km; total flight duration: 9.3 ± 0.3 h; WBF: 44.0 ± 0.5 Hz at 24°C and 75% RH). The age for optimal flight was considered to be 2-3 d old. Temperature and RH also significantly affected flight ability and WBF; flight was optimal from 23°C to 25°C and 64-75% RH. Because M. brassicae thus has great potential to undertake long-distance migration, better knowledge of its flight behavior and migration will help establish a pest forecasting and early-warning system.


Assuntos
Voo Animal , Mariposas/fisiologia , Asas de Animais/fisiologia , Fatores Etários , Animais , Feminino , Umidade , Masculino , Fatores Sexuais , Temperatura Ambiente
4.
Oecologia ; 192(2): 543-552, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31919693

RESUMO

The sudden interruption of recurring larch budmoth (LBM; Zeiraphera diniana or griseana Gn.) outbreaks across the European Alps after 1982 was surprising, because populations had regularly oscillated every 8-9 years for the past 1200 years or more. Although ecophysiological evidence was limited and underlying processes remained uncertain, climate change has been indicated as a possible driver of this disruption. An unexpected, recent return of LBM population peaks in 2017 and 2018 provides insight into this insect's climate sensitivity. Here, we combine meteorological and dendrochronological data to explore the influence of temperature variation and atmospheric circulation on cyclic LBM outbreaks since the early 1950s. Anomalous cold European winters, associated with a persistent negative phase of the North Atlantic Oscillation, coincide with four consecutive epidemics between 1953 and 1982, and any of three warming-induced mechanisms could explain the system's failure thereafter: (1) high egg mortality, (2) asynchrony between egg hatch and foliage growth, and (3) upward shifts of outbreak epicentres. In demonstrating that LBM populations continued to oscillate every 8-9 years at sub-outbreak levels, this study emphasizes the relevance of winter temperatures on trophic interactions between insects and their host trees, as well as the importance of separating natural from anthropogenic climate forcing on population behaviour.


Assuntos
Larix , Mariposas , Animais , Mudança Climática , Surtos de Doenças , Dinâmica Populacional
5.
Bull Entomol Res ; 110(1): 68-76, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31190650

RESUMO

In the Mediterranean and temperate regions, an increase in the frequency and intensity of drought events has been recorded, probably due to climate change. In consequence, trees will more frequently experience hydric stress, a condition that can be expected to affect insect-tree interactions, while adaptation mechanisms may be further in course. The effect of tree water stress on the performance of two allochronic populations of Thaumetopoea pityocampa was here studied. Namely, we compared a unique population of this insect, in which the larvae develop in the summer (SP), with the typical population having winter larval development (WP), to test the adaptation hypothesis to host plant status. Larvae of each population were fed on needles of young potted Pinus pinaster plants under two water supply regimes: (i) well-watered (control) and (ii) subjected to 3 months of drought stress. Compared to control, stressed plants had higher amounts of soluble sugars, phenols, and higher C/N ratio, whereas water content and chlorophylls concentrations were lower. In general, T. pityocampa larvae had lower performances on water-stressed plants, as shown by lower survival rates, lower needle consumption, and longer development times. Yet, the detrimental effects of tree stress were only significant for the WP larvae, while SP larvae were able to overcome such conditions. Results demonstrate that tree water stress can negatively affect T. pityocampa populations. Furthermore, the evidence is also provided that responses to the physiological condition of the host trees may occur at the population level, as a result of adaptation mechanisms driven by climate change.


Assuntos
Adaptação Biológica , Herbivoria , Mariposas/crescimento & desenvolvimento , Pinus/fisiologia , Água/fisiologia , Animais , Larva/crescimento & desenvolvimento , Masculino , Pressão Osmótica
6.
Bull Entomol Res ; 110(1): 96-105, 2020 Feb.
Artigo em Italiano | MEDLINE | ID: mdl-31190656

RESUMO

Diamides have been used worldwide to manage the diamondback moth (DBM), Plutella xylostella L. (Lepidoptera: Plutellidae), however some strains showed resistance to these molecules. Also, pheromone traps could be used to manage this pest, hence reducing the use of insecticides in the field. Resistant DBM strains may have biological disadvantages in comparison to susceptible strains in areas without sprays, including reduction in fitness or behavioral changes. Therefore, the aim of this study was to investigate whether DBM strains resistant to chlorantraniliprole showed adaptive costs that could alter male attraction to the sex pheromone, in comparison to susceptible strains in the laboratory and semi-field conditions. First, the LC1, LC10, LC25, and LC50 of DBM to chlorantraniliprole were established, which were 0.003, 0.005, 0.007, and 0.011 mg a.i. liter-1, and 5.88, 24.80, 57.22, and 144.87 mg a.i. liter-1 for the susceptible and resistant strains, respectively. Development and reproduction of DBM strains subjected to those concentrations were compared. Later, male response to the sex pheromone was investigated in a Y-tube in the laboratory and in a greenhouse to pheromone traps. Resistant DBM strain showed an adaptive cost in comparison to the susceptible strain that can result in a delay in population growth in the field when selection pressure is absent. Conversely, resistant males have no olfactory response alteration in comparison to susceptible males, consistently at 3 (P = 0.6848) and 7 days (P = 0.9140) after release, suggesting that pheromone traps continue to be a viable alternative to manage DBM in an IPM system.


Assuntos
Adaptação Biológica , Inseticidas , Mariposas/fisiologia , Comportamento Sexual Animal/fisiologia , ortoaminobenzoatos , Animais , Resistência a Inseticidas/fisiologia , Masculino , Atrativos Sexuais , Olfato
7.
J Agric Food Chem ; 68(1): 88-96, 2020 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-31826619

RESUMO

Solanum rostratum is a worldwide malignant invasive weed, causing serious harm to the ecological environment and biodiversity. Strong chemical defense against herbivorous insects is supposed to be one of the successful invasive mechanisms of this exotic plant. However, the real defense components and their action mechanisms and distributions are still unknown. To address these problems, we bioassay-guided isolated compounds from the aerial part of S. rostratum and determined their structures using high-resolution electrospray ionization mass spectrometry, nuclear magnetic resonance, and electronic circular dichroism calculation. One new and seven known compounds were identified, and all of the isolates exhibited different levels of antifeedant activities, especially compounds 1 and 4. Consistently, compounds 1 and 4 displayed potent inhibitory effects on antifeedant-related enzymes (AchE and CarE). The action mechanisms of active compounds 1 and 4 were revealed by molecular docking and molecular dynamic simulation studies. Furthermore, the distributions of the active compounds in leaves, stems, and flowers were also analyzed by liquid chromatography-mass spectrometry.


Assuntos
Comportamento Alimentar/efeitos dos fármacos , Inseticidas/farmacologia , Mariposas/efeitos dos fármacos , Extratos Vegetais/farmacologia , Plantas Daninhas/química , Solanum/química , Animais , Flores/química , Flores/metabolismo , Inseticidas/química , Inseticidas/isolamento & purificação , Inseticidas/metabolismo , Simulação de Acoplamento Molecular , Estrutura Molecular , Mariposas/fisiologia , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/metabolismo , Folhas de Planta/química , Folhas de Planta/metabolismo , Plantas Daninhas/metabolismo , Metabolismo Secundário , Solanum/metabolismo , Espectrometria de Massas por Ionização por Electrospray
8.
J Chem Ecol ; 46(1): 40-47, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31808076

RESUMO

Cuticular hydrocarbons (CHCs) are the main components of the epicuticular wax layer that in many insects functions as a barrier against desiccation. CHCs also play many other roles, including serving as sex pheromones, kairomones, primer pheromones, and colony-, caste-, species- and sex-recognition signals. In insects, CHC profiles can vary depending upon age, species, sex, and strain. Understanding factors associated with variation in hydrocarbon profiles is important for identifying potential vulnerabilities relating to pest ecology and life histories and for developing tools for pest monitoring and management strategies. In this study, we assessed potential sources of variation in CHC profiles in the navel orangeworm Amyelois transitella (Walker) (Lepidoptera: Pyralidae), an economically important pest of nut crops in California. Using coupled gas chromatography-mass spectrometry, we characterized and compared CHC profiles between adults of pyrethroid-resistant (R347) and susceptible (ALMOND) strains. We further compared CHC profiles from adults differing in age (1, 3, 5, and 7 d post-eclosion) and sex. Hydrocarbon profiles comprised 47 different CHCs in detectable quantities that ranged from C17 to C43 in chain length and included straight-chain alkanes and a variety of mono-, di-, and tri-methylalkanes. Adults from resistant populations had greater quantities of CHCs in total than those from susceptible strains, but relative quantities of individual components were similar. The six most abundant compounds were n-pentacosane, n-heptacosane, n-nonacosane, n-hentriacontane, 11,25 + 13,23 + 15,21-dimethylpentatriacontane, and 13,23 + 11,25 + 9,17-dimethylheptatriacontane. Post-eclosion, total CHCs increased with adult age, with males producing greater quantities than females at all ages. Our results show that CHC profiles vary depending on age, sex, and strain and suggest that CHC profiles may be useful as biomarkers to differentiate between insecticide- resistant and susceptible populations.


Assuntos
Hidrocarbonetos/química , Mariposas/química , Animais , Cromatografia Líquida de Alta Pressão , Feminino , Hidrocarbonetos/análise , Masculino , Espectrometria de Massas , Mariposas/metabolismo , Análise de Componente Principal , Caracteres Sexuais , Fatores de Tempo
9.
Bull Entomol Res ; 110(1): 144-154, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31218990

RESUMO

We examined the role of the most important metabolic enzyme families in the detoxification of neurotoxic insecticides on adult males and females from susceptible populations of Cydia pomonella (L.), Grapholita molesta (Busck), and Lobesia botrana (Denis & Schiffermüller). The interaction between the enzyme families - carboxylesterases (EST), glutathione-S-transferases (GST), and polysubstrate monooxygenases (PSMO) - with the insecticides - chlorpyrifos, λ-cyhalothrin, and thiacloprid - was studied. Insect mortality arising from the insecticides, with the application of enzyme inhibitors - S,S,S-tributyl phosphorotrithioate (DEF), diethyl maleate (DEM), and piperonyl butoxide (PBO) - was first determined. The inhibitors' influence on EST, GST, and PSMO activity was quantified. EST and PSMO (the phase-I enzymatic activities) were involved in the insecticide detoxification in the three species for both sexes, highlighting the role of EST, whereas GST (phase-II enzymes) was involved only in G. molesta insecticide detoxification. L. botrana exhibited, in general, the highest level of enzymatic activity, with a significantly higher EST activity compared with the other species. It was the only species with differences in the response between sexes, with higher GST and PSMO activity in females than in males, which can be explained as the lower susceptibility of the females to the tested insecticides. A positive correlation between PSMO activity and the thiacloprid LD50s in the different species-sex groups was observed explaining the species-specific differences in susceptibility to the product reported in a previous study.


Assuntos
Inativação Metabólica , Inseticidas , Mariposas/enzimologia , Animais , Feminino , Masculino
10.
Bull Entomol Res ; 110(1): 136-143, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31203829

RESUMO

The oriental armyworm, Mythimna separata is an important crop pest in eastern Asia. Nocturnal insects, including nocturnal moths, have phototactic behavior to an artificial light source. Phototactic behavior in insects is species-specific in response to different wavelengths of light sources. Our previous study showed that green (520 nm) light emitting diode (LED) light resulted in a significantly higher phototactic behavior in M. separata moths compared to the other wavelength LED lights. The goal of the present study is to investigate the influence of green light illumination on biological characteristics of different developmental stages in M. separata. Our results revealed that when different developmental stages of M. separata were exposed to the green light illumination in a dark period, several biological characteristics in all developmental stages except for egg stage were positively changed, but those of F1 generation M. separata which are next generation of the adults exposed to the green light did not significantly change compared with the control level. These findings suggest that green light illumination at night (or dark period) has a positive effect on the development and longevity of M. separata.


Assuntos
Mariposas/efeitos da radiação , Animais , Feminino , Larva/efeitos da radiação , Luz , Longevidade/efeitos da radiação , Masculino , Mariposas/crescimento & desenvolvimento , Óvulo/efeitos da radiação , Pupa/efeitos da radiação , Reprodução/efeitos da radiação
11.
Bull Entomol Res ; 110(1): 57-67, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31217039

RESUMO

Glyphodes pyloalis Walker (Lepidoptera: Pyralididae) is a common pest in sericulture and has developed resistance to different insecticides. However, the mechanisms involved in insecticide resistance of G. pyloalis are poorly understood. Here, we present the first whole-transcriptome analysis of differential expression genes in insecticide-resistant and susceptible G. pyloalis. Clustering and enrichment analysis of DEGs revealed several biological pathways and enriched Gene Ontology terms were related to detoxification or insecticide resistance. Genes involved in insecticide metabolic processes, including cytochrome P450, glutathione S-transferases and carboxylesterase, were identified in the larval midgut of G. pyloalis. Among them, CYP324A19, CYP304F17, CYP6AW1, CYP6AB10, GSTs5, and AChE-like were significantly increased after propoxur treatment, while CYP324A19, CCE001c, and AChE-like were significantly induced by phoxim, suggesting that these genes were involved in insecticide metabolism. Furthermore, the sequence variation analysis identified 21 single nucleotide polymorphisms within CYP9A20, CYP6AB47, and CYP6AW1. Our findings reveal many candidate genes related to insecticide resistance of G. pyloalis. These results provide novel insights into insecticide resistance and facilitate the development of insecticides with greater specificity to G. pyloalis.


Assuntos
Inativação Metabólica/genética , Resistência a Inseticidas/genética , Mariposas/metabolismo , Animais , Sistema Enzimático do Citocromo P-450/genética , Feminino , Perfilação da Expressão Gênica , Genes de Insetos , Masculino , Mariposas/genética , Polimorfismo de Nucleotídeo Único , Transcriptoma
12.
Insect Sci ; 27(2): 212-223, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30397994

RESUMO

Trehalose-6-phosphate synthase (TPS), an enzyme that hydrolyzes two glucose molecules to yield trehalose, plays a pivotal role in various physiological processes. In this study, we cloned the trehalose-6-phosphate synthase gene (HvTPS) and investigated its expression patterns in various tissues and developmental stages in Heortia vitessoides Moore (Lepidoptera: Crambidae). HvTPS was highly expressed in the fat body and after pupation or before molting. We knocked down TPS in H. vitessoides by RNA interference and found that 3.0 µg of dsHvTPS resulted in optimal interference at 24 h and 36 h post-injection and caused a sharp decline in the survival rate during the 5th instar larval-pupal stage and obviously abnormal or lethal phenotypes. Additionally, compared to the controls, TPS activity and trehalose contents were significantly lower and the glucose content was significantly higher 24 h or 36 h after injection with 3.0 µg of dsHvTPS. Furthermore, the silencing of HvTPS suppressed the expression of six key genes in the chitin biosynthesis pathway and one key gene related to lipid catabolism. The expression levels of two genes associated with lipid biosynthesis were upregulated. These results strongly suggest that HvTPS is essential for the normal growth and development of H. vitessoides and provide a reference for further studies of the utility of key genes involved in chitin and lipid biosynthesis for controlling insect development.


Assuntos
Glucosiltransferases/genética , Mariposas/enzimologia , Animais , Quitina/biossíntese , Larva/metabolismo , Lipídeos/biossíntese , Mariposas/genética , Interferência de RNA , Análise de Sequência de DNA
13.
Insect Sci ; 27(2): 239-255, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30328680

RESUMO

Larval Galleria mellonella (L.) hemocytes form microaggregates in response to stimulation by Gram-positive bacteria. Hemocyte adhesion to foreign materials is mediated by the cAMP/ protein kinase A pathway and the ß-subunit of cholera toxin using a cAMP-independent mechanism. Cholera toxin-induced microaggregation was inhibited by the integrin inhibitory RGDS peptide, implying integrins may be part of the mechanism. Based on the types of mammalian integrin-antibody reactive proteins affecting hemocyte adhesion and bacterial-induced responses α5 , αv , ß1 , and ß3 subunits occurred on both granular cell and plasmatocyte hemocyte subtypes. A fluorescent band representing the binding of rabbit α5 -integrin subunit antibodies occurred between adhering heterotypic hemocytes. The frequency of the bands was increased by cholera toxin. The α5 and ß1 rabbit integrin subunit antibodies inhibited removal of Bacillus subtilis (Cohn) from the hemolymph in vivo. A α5 ß1 -specific synthetic peptide blocker similarly diminished hemocyte function whereas the αv ß3 -specific inhibitory peptide and the corresponding integrin subunit antibodies did not influence nonself hemocyte activities. Western blots revealed several proteins reacting with a given integrin-antibody subtype. Thus integrin-antibody reactive proteins (which may include integrins) with possible α5 and ß1 epitopes modulate immediate hemocyte function. Confocal microscopy established plasmatocyte adhesion to and rosetting over substrata followed by granular cell microaggregate adhesion to plasmatocytes during early stage nodulation.


Assuntos
Hemócitos/imunologia , Integrinas/imunologia , Mariposas/imunologia , Animais , Larva/imunologia
14.
Insect Sci ; 27(1): 49-57, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29999564

RESUMO

In agro-ecosystems, plants are important mediators of interactions between their associated herbivorous insects and microbes, and any change in plants induced by one species may lead to cascading effects on interactions with other species. Often, such effects are regulated by phytohormones such as jasmonic acid (JA) and salicylic acid (SA). Here, we investigated the tripartite interactions among rice plants, three insect herbivores (Chilo suppressalis, Cnaphalocrocis medinalis or Nilaparvata lugens), and the causal agent of rice blast disease, the fungus Magnaporthe oryzae. We found that pre-infestation of rice by C. suppressalis or N. lugens but not by C. medinalis conferred resistance to M. oryzae. For C. suppressalis and N. lugens, insect infestation without fungal inoculation induced the accumulation of both JA and SA in rice leaves. In contrast, infestation by C. medinalis increased JA levels but reduced SA levels. The exogenous application of SA but not of JA conferred resistance against M. oryzae. These results suggest that pre-infestation by C. suppressalis or N. lugens conferred resistance against M. oryzae by increasing SA accumulation. These findings enhance our understanding of the interactions among rice plant, insects and pathogens, and provide valuable information for developing an ecologically sound strategy for controlling rice blast.


Assuntos
Hemípteros/fisiologia , Herbivoria , Magnaporthe/fisiologia , Mariposas/fisiologia , Oryza/microbiologia , Doenças das Plantas/microbiologia , Ácido Salicílico/metabolismo , Animais , Resistência à Doença/fisiologia
15.
Arch Insect Biochem Physiol ; 103(1): e21631, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31587381

RESUMO

Soybean is one of most consumed and produced grains in the world, and Anticarsia gemmatalis is a pest that causes great damage to this crop due to severe defoliation during its larval phase. Plants have mechanisms that lead to the inhibition of proteases in the intestine of these herbivores, hampering their development. Understanding this complex protease inhibitor is important for pest control. The objective of this study was to evaluate the enzymatic profiles of the intestinal proteases of the soybean caterpillar at different instars. For this, the proteolytic profile of the gut in the third, fourth, and fifth instars were analyzed. Irreversible inhibitors of proteases were separately incubated with A. gemmatalis enzyme extracts at the third, fourth, and fifth instar to assess the contribution of these proteases to total proteolytic activity. The enzymatic extracts were also evaluated with specific substrates to confirm changes in the specific activities of trypsin-like, chymotrypsin-like, and cysteine proteases at different instars. The results showed that the protease profile of A. gemmatalis gut changes throughout its larval development. The activity of cysteine proteases was more intense in the first instar. On the contrary, the serine proteases showed major activities in the late stages of the larval phase. Zymogram analysis and protein identification by liquid chromatography-mass spectrometry indicated serine protease as the main protease class expressed in the fifth instar. These results may shift the focus from the rational development of the protease inhibitor to A. gemmatalis and other Lepidoptera, as the expression of major proteases is not constant.


Assuntos
Mariposas/enzimologia , Peptídeo Hidrolases/química , Animais , Trato Gastrointestinal/enzimologia , Trato Gastrointestinal/crescimento & desenvolvimento , Larva/enzimologia , Larva/crescimento & desenvolvimento , Mariposas/crescimento & desenvolvimento , Peptídeo Hidrolases/classificação
16.
Arch Insect Biochem Physiol ; 103(1): e21636, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31612557

RESUMO

As a member of the low-density lipoprotein receptor (LDLR) superfamily, vitellogenin (Vg) receptor (VgR) is responsible for the uptake of Vg into developing oocytes and is a potential target for pest control. Here, a full-length VgR complementary DNA (named as CsVgR) was isolated and characterized in the rice stem borer, Chilo suppressalis. The composite CsVgR gene contained an open reading frame of 5,484 bp encoding a protein of 1,827 amino acid residues. Structural analysis revealed that CsVgR contained two ligand-binding domains (LBDs) with four Class A (LDLRA ) repeats in LBD1 and seven in LBD2, which was structurally different from most non-Lepidopteran insect VgRs having five repeats in LBD1 and eight in LBD2. The developmental expression analysis showed that CsVgR messenger RNA expression was first detectable in 3-day-old pupae, sharply increased in newly emerged female adults, and reached a peak in 2-day-old female adults. Consistent with most other insects VgRs, CsVgR was exclusively expressed in the ovary. Notably, injection of dsCsVgR into late pupae resulted in fewer follicles in the ovarioles as well as reduced fecundity, suggesting a critical role of CsVgR in female reproduction. These results may contribute to the development of RNA interference-mediated disruption of reproduction as a control strategy of C. suppressalis.


Assuntos
Proteínas do Ovo/genética , Mariposas/genética , Receptores de Superfície Celular/genética , Animais , Proteínas do Ovo/química , Proteínas do Ovo/metabolismo , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Proteínas de Insetos/metabolismo , Mariposas/crescimento & desenvolvimento , Mariposas/metabolismo , Ovário/crescimento & desenvolvimento , Ovário/metabolismo , Filogenia , Interferência de RNA , RNA Mensageiro/metabolismo , Receptores de Superfície Celular/química , Receptores de Superfície Celular/metabolismo , Análise de Sequência de Proteína
17.
Arch Insect Biochem Physiol ; 103(1): e21637, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31625209

RESUMO

Anticarsia gemmatalis represents a relevant factor for lowering soybean and other legume crop productivities. Protease inhibitors affect protein degradation and reduce the availability of amino acids, impairing the development and survival of insect pests. To evaluate the possible use of proteinaceous protease inhibitors in the management of this pest, the activities of midgut proteases and the growth and development of A. gemmatalis larvae exposed to soybean Bowman-Birk trypsin-chymotrypsin inhibitor (SBBI) and soybean Kunitz trypsin inhibitor (SKTI) were determined. The survival curves obtained using Kaplan-Meier estimators indicated that SKTI and SBBI stimulated larval survival. However, the development of A. gemmatalis was delayed, and prepupal weight decreased in the presence of both inhibitors. The results showed that SKTI and SBBI inhibited the trypsin-like and total proteolytic activities of larvae on the 12th day after eclosion. On the 15th day after eclosion, larvae exposed to SKTI increased the activities of trypsin and total proteases. Although SKTI and SBBI did not affect the survival of the insect, they had effects on midgut proteases in a stage wherein A. gemmatalis fed voraciously, increased the larval cycle, and decreased prepupal weight. These findings provide baseline information about the potential of proteinaceous protease inhibitors to manage the velvetbean caterpillar, avoiding chemical pesticides.


Assuntos
Mariposas/efeitos dos fármacos , Inibidor da Tripsina de Soja de Bowman-Birk/farmacologia , Inibidor da Tripsina de Soja de Kunitz/farmacologia , Animais , Trato Gastrointestinal/enzimologia , Larva/efeitos dos fármacos , Larva/enzimologia , Larva/crescimento & desenvolvimento , Mariposas/enzimologia , Mariposas/crescimento & desenvolvimento , Peptídeo Hidrolases/metabolismo , Inibidores de Proteases/farmacologia , Soja/enzimologia , Tripsina/metabolismo
18.
Arch Insect Biochem Physiol ; 103(1): e21640, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31667893

RESUMO

Long noncoding RNAs (lncRNAs) that have immune responses to various stimuli have been identified in some insects. One type of pathogen-associated molecular pattern, double-stranded RNA (dsRNA), can trigger the RNA interference (RNAi) pathway and immune response. Interestingly, there has been no research into characterizing the relationship between lncRNA and dsRNA-induced RNAi pathways. In this study, dsRNA-induced lncRNAs were investigated in two species of lepidopteran insects, Helicoverpa armigera and Plutella xylostella, and one species of coleopteran insects, Tribolium castaneum. Between untreated group and dsRNA-induced group; 3,463 H. armigera, 6,245 P. xylostella, and 3,067 T. castaneum differentially expressed lncRNAs were identified while 156 H. armigera, 247 P. xylostella, 415 T. castaneum lncRNAs and their putative target genes showed consistent changes in gene expression. In T. castaneum, most target genes of the differentially expressed lncRNAs are enriched in the cyclic adenosine monophosphate signaling pathway, ABC transporters, and Janus kinase-signal transducers and activators of the transcription signaling pathway. Conversely, in H. armigera and P. xylostella, the differentially expressed lncRNAs were mainly enriched in the metabolic, digestive, and synthetic signaling pathways. This result indicates that dsRNA-induced lncRNA is species-dependent. We also found that both Dicer-2 and the lncRNA that targets Dicer-2 were significantly upregulated after dsRNA treatment in P. xylostella, indicating that some lncRNAs may be involved in the regulation of the core RNAi pathway in insects. Our results are the first to identify a relationship between lncRNAs and dsRNA in various insect species with different RNAi efficiencies. These results provide a reference for future study of the dsRNA-induced RNAi pathway and different RNAi efficiencies among insect species.


Assuntos
Mariposas/genética , RNA de Cadeia Dupla/farmacologia , RNA Longo não Codificante/metabolismo , Tribolium/genética , Animais , Expressão Gênica , Mariposas/metabolismo , Interferência de RNA , Transdução de Sinais , Tribolium/metabolismo
19.
Chemosphere ; 238: 124676, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31473531

RESUMO

While sublethal effects of insecticide on insect development have been widely studied, the underlying mechanisms remain elusive. Our previous studies revealed that sublethal concentrations of chlorantraniliprole significantly increased the juvenile hormone levels and resulted in both prolonged developmental time and reduced fecundity in Chilo suppressalis. In the present study, we evaluated the sublethal effects of chlorantraniliprole on molting hormone (MH) levels and mRNA expressions of three Halloween genes including CsCYP307A1, CsCYP306A1 and CsCYP314A1 in C. suppressalis. The results showed that the MH levels in different developmental stages of C. suppressalis were decreased after exposure to LC10 and LC30 of chlorantraniliprole. However, analysis of temporal expression profiles revealed that the mRNA levels of three Halloween genes were not closely correlated with the ecdysteroid titers in C. suppressalis. Notably, the transcript levels of CsCYP307A1, CsCYP306A1 and CsCYP314A1 were induced after treatment with sublethal concentrations of chlorantraniliprole in specific developmental stages. These results indicated that chlorantraniliprole had adverse effects on insect MH biosynthesis, and in addition to the involvement in MH biosynthesis, CsCYP307A1, CsCYP306A1 and CsCYP314A1 may also play important roles in the detoxification metabolism of chlorantraniliprole in C. suppressalis.


Assuntos
Ecdisona/metabolismo , Inseticidas/farmacologia , Hormônios Juvenis/metabolismo , Larva/efeitos dos fármacos , Muda/efeitos dos fármacos , Mariposas/embriologia , ortoaminobenzoatos/farmacologia , Animais , Hormônios Juvenis/genética , Muda/genética , Mariposas/efeitos dos fármacos , RNA Mensageiro/biossíntese
20.
J Chem Ecol ; 46(1): 10-20, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31845137

RESUMO

Female moths release sex pheromone to attract mates. In most species, sex pheromone is produced in, and released from, a specific gland. In a previous study, we used empirical data and compartmental modeling to account for the major pheromone gland processes of female Chloridea virescens: synthesis, storage, catabolism and release; we found that females released little (20-30%) of their pheromone, with most catabolized. The recent publication of a new pheromone collection method led us to reinvestigate pheromone release and catabolism in C. virescens on the basis that our original study might have underestimated release rate (thereby overestimating catabolism) due to methodology and females not calling (releasing) continuously. Further we wished to compare pheromone storage/catabolism between calling and non-calling females. First, we observed calling intermittency of females. Then, using decapitated females, we used the new collection method, along with compartmental modeling, gland sampling and stable isotope labeling, to determine differences in pheromone release, catabolism and storage between (forced) simulated calling and non-calling females. We found, (i) intact 1 d females call intermittently; (ii) pheromone is released at a higher rate than previously determined, with simulations estimating that continuously calling females release ca. 70% of their pheromone (only 30% catabolized); (iii) extension (calling)/retraction of the ovipositor is a highly effective "on/off' mechanism for release; (iv) both calling and non-calling females store most pheromone on or near the gland surface, but calling females catabolize less pheromone; (v) females are capable of producing and releasing pheromone very rapidly. Thus, not only is the moth pheromone gland efficient, in terms of the proportion of pheromone released Vs. catabolized, but it is highly effective at shutting on/off a high flux of pheromone for release.


Assuntos
Mariposas/fisiologia , Atrativos Sexuais/metabolismo , Comportamento Sexual Animal , Aldeídos/análise , Aldeídos/farmacologia , Animais , Isótopos de Carbono/química , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Glucose/química , Glucose/metabolismo , Marcação por Isótopo , Masculino , Glândulas Odoríferas/metabolismo , Atrativos Sexuais/análise , Atrativos Sexuais/farmacologia , Comportamento Sexual Animal/efeitos dos fármacos
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