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1.
Oecologia ; 195(2): 453-467, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33523300

RESUMO

Patterns of ß-diversity can provide insight into forces shaping community assembly. We analyzed species-rich insect assemblages in two reserve fragments that had once been part of one contiguous Mediterranean coastal pine forest. Local environments are still similar across both fragments, but their landscape context differs strongly, with one surrounded by intense agricultural land, while the other neighbors the urbanized area of Ravenna. Using 23,870 light-trap records of 392 moth species, and multiple local and landscape metrics, we compared the relative importance of habitat- versus landscape-scale environmental factors for shaping small-scale variation in differentiation and proportional insect ß-diversity across 30 sites per reserve. Moth assemblage composition differed substantially between fragments, most likely due to ecological drift and landscape-scale variation. For proportional ß-diversity, especially local forest structure was important. At well-developed forest sites, additive homogenization could be observed, whereas the lack of typical forest species at dry, dense, and younger forest sites increased species turnover (subtractive heterogenization). For differentiation ß-diversity, local and landscape-scale factors were equally important in both reserves. At the landscape-scale (500 m radius around light-trapping sites) the proximity to urban areas and the fraction of human-altered land were most important. At the habitat scale, gradients in soil humidity, nutrient levels and forest structure mattered most, whereas plant diversity had very little explanatory power. Overall, landscape-scale anthropogenic alterations had major effects on moth communities inside the two conservation areas. Yet, even for these parts of one formerly contiguous forest trajectories in community change were remarkably idiosyncratic.


Assuntos
Biodiversidade , Mariposas , Animais , Ecossistema , Florestas , Humanos , Solo
2.
Pestic Biochem Physiol ; 172: 104769, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33518040

RESUMO

Cantharidin (CTD) is a natural toxin with effective toxicity to lepidopteran pests. Nevertheless, little information is available on whether pests develop resistance to CTD. After being exposed to CTD (50 mg/L to 90 mg/L) or 10 generations, the resistance ratio of laboratory selected cantharidin-resistant Mythimna separata (Cantharidin-SEL) strain was only elevated 1.95-fold. Meanwhile, the developmental time for M. separata was prolonged (delayed1.65 in males and 1.84 days in females). The reported CTD target, the serine/threonine phosphatases (PSPs), have not been shown significant activity variation during the whole process of CTD-treatment. The activity of detoxification enzymes (cytochrome monooxygenase P450, glutathione-S-transferase (GST) and carboxylesterase) were affected by CTD selection, but this change was not mathematically significant. More importantly, no obvious cross-resistance with other commonly used insecticides was observed in the M. separata population treated with CTD for 10 generations (resistance ratios were all lower 2.5). Overall, M. separata is unlikely to produce target-site insensitivity resistance, metabolic resistance to CTD. Meanwhile, cantharidin-SEL is not prone to develop cross-resistance with other insecticides. These results indicate that CTD is a promising biogenetic lead compound which can be applied in the resistance management on M. separata.


Assuntos
Inseticidas , Lepidópteros , Mariposas , Animais , Cantaridina , Feminino , Resistência a Inseticidas , Inseticidas/farmacologia , Chumbo , Masculino
3.
Pestic Biochem Physiol ; 172: 104765, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33518052

RESUMO

The environmental pollution, evolution of resistance, and risks to human and aquatic animal health associated with pesticide application have attracted much attention globally. Herein, we tested the capacity of diallyl trisulfide (DAT) from garlic essential oil to control the destructive stored-product pest, Sitotroga cerealella. The effects of DAT on the total content of cuticular chitin and structure of adults S. cerealella were evaluated. This study was the first to investigate changes in chitin structure in adults due to exposure to DAT through Fourier-transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, and differential scanning calorimetry. The results of these analyses revealed that the cuticular chitin content of pests decreased after DAT treatment. DAT treatment also reduced thermal stability and crystallinity of chitin. These findings indicate that DAT is a potent biopesticide that is active against the moth, and establishes the basis for its use as an IPM and alternative to chitin synthesis inhibitors.


Assuntos
Alho , Mariposas , Óleos Voláteis , Compostos Alílicos , Animais , Quitina , Sulfetos
4.
Bull Environ Contam Toxicol ; 106(2): 295-301, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33386859

RESUMO

Pyrethroid and indoxacarb are commonly used pesticides to control the fall armyworm (Spodoptera frugiperda) in the crops. There are a series of consequences caused by the use of pyrethroid and indoxacarb pesticides under emergency control, such as pest resistance development, contamination of soil, water, and farm products. This study analyzed the structure and physiological function of the sodium channel in S. frugiperda, which is an important step to elaborate the resistance mechanism of S. frugiperda to indoxacarb and pyrethroid pesticides. According to genetic analysis, the cloned cDNA sequences of sodium channel in S. frugiperda (SfNav) showed the shortest genetic distance with that of the sodium channel in Helicoverpa armigera. Under the induction of three pesticides, the expression of SfNav decreased in the first 12 h and then increased after 24 h. It was concluded that SfNav had a typical structure of the sodium channel of insects and its down-regulated expression can decrease the combination of S. frugiperda with pyrethroid and indoxacarb pesticides. The up-regulated expression of SfNav was conducive to the enhancement of the pesticide resistance.


Assuntos
Mariposas , Praguicidas , Piretrinas , Animais , Produtos Agrícolas , Larva , Piretrinas/toxicidade , Spodoptera/genética
5.
Arch Insect Biochem Physiol ; 106(2): e21763, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33426694

RESUMO

Peptidoglycan recognition proteins (PGRPs) are well known for their abilities to recognize or hydrolyze peptidoglycan (PGN), one of the major bacterial cell wall components. However, much less is known about their antifungal activities. PGRP-S1 was previously identified from a crop pest, Mythimna separata (Walker) (Lepidoptera: Noctuidae). PGRP-S1 showed bacteriolytic activities against Gram-positive and Gram-negative bacteria. In this study, tissue expression analysis showed that PGRP-S1 was mainly expressed in the midgut of naïve larvae. The induction analysis showed that it was significantly induced in the larval midgut 12 h post the injection of Beauveria bassiana conidia. To identify the key residues that are related to its microbicidal activities, the structure of PGPR-S1 was predicted for structural comparison and molecular docking analysis. Six residues (H61, H62, Y97, H171, T175, and C179) were mutated to Ala individually by site-directed mutagenesis. The recombinant wild-type (WT) and mutant proteins were expressed and purified. The recombinant proteins bound to different polysaccharides, PGNs, and bacteria. H61A, Y97A, H171A, and C179A lost amidase activity. Accordingly, antibacterial assay and scanning electron microscopy confirmed that only H62A and T175A retained bacteriolytic activities. The germination of B. bassiana conidia was significantly inhibited by WT, H61A, Y97A, T175A, and C179A mutants. Electron microscopy showed that some conidia became ruptured after treatment. The growth of hyphae was inhibited by the WT, H61A, H62A, and T175A. In summary, our data showed that different residues of PGRP-S1 are involved in the antibacterial and antifungal activities.


Assuntos
Beauveria/fisiologia , Proteínas de Transporte/genética , Proteínas de Insetos/genética , Mariposas/genética , Sequência de Aminoácidos , Animais , Proteínas de Transporte/química , Proteínas de Transporte/metabolismo , Imunidade Inata , Proteínas de Insetos/química , Proteínas de Insetos/metabolismo , Larva/crescimento & desenvolvimento , Simulação de Acoplamento Molecular , Mariposas/crescimento & desenvolvimento , Mariposas/metabolismo , Filogenia , Estrutura Secundária de Proteína , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Alinhamento de Sequência , Esporos Fúngicos/fisiologia
6.
Sci Total Environ ; 764: 144607, 2021 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-33387770

RESUMO

Insect defoliations are a major natural disturbance in high-latitude ecosystems and are expected to increase in frequency and severity due to current climatic change. Defoliations cause severe reductions in biomass and carbon investments that affect the functioning and productivity of tundra ecosystems. Here we combined dendro-anatomical analysis with chemical imaging to investigate the direct and lagged effects of insect outbreaks on carbon investment. We analysed the content of lignin vs. holocellulose, i.e. unspecified carbohydrates in xylem samples of Salix glauca L. collected at Iffiartarfik, Nuuk fjord, Greenland, featuring two outbreak events of the moth Eurois occulta L. Cross sections of the growth rings corresponding to both outbreaks ±3 years were analysed using confocal Raman imaging to identify possible chemical signatures related to insect defoliation on fibres, vessels, and ray parenchyma cells and to get insight into species-specific defence responses. Outbreak years with narrower rings and thinner fibre cell walls are accompanied by a change in the content of cell-wall polymers but not their underlying chemistry. Indeed, during the outbreaks the ratio between lignin and carbohydrates significantly increased in fibre but not vessel cell walls due to an increase in lignin content coupled with a reduced content of carbohydrates. Parenchyma cell walls and cell corners did not show any significant changes in the cell-wall biopolymer content. The selective adjustment of the cell-wall composition of fibres but not vessels under stressful conditions could be related to the plants priority to maintain an efficient hydraulic system rather than mechanical support. However, the higher lignin content of fibre cell walls formed during the outbreak events could increase mechanical stiffness to the thin walls by optimizing the available resources. Chemical analysis of xylem traits with Raman imaging is a promising approach to highlight hidden effects of defoliation otherwise overlooked with classical dendroecological methods.


Assuntos
Mariposas , Salix , Animais , Parede Celular , Surtos de Doenças , Ecossistema , Groenlândia , Lignina , Xilema
7.
Environ Pollut ; 271: 116271, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33401210

RESUMO

Insect gut microbiotas have a variety of physiological functions for host growth, development, and immunity. Bacillus thuringiensis (Bt) is known to kill insect pests by releasing insecticidal protoxins, which are activated in the insect midgut. However, the interplay among Bt infection, host immunity, and gut microbiota are still unclear. Here we show that Bt Cry1Ac protoxin interacts with the gut microbiota to accelerate the mortality of P. xylostella larvae. Cry1Ac protoxin was found to cause a dynamic change in the midgut and hemocoel microbiota of P. xylostella, with a significant increase in bacterial load and a significant reduction in bacterial diversity. In turn, loss of gut microbiota significantly decreased the Bt susceptibility of P. xylostella larvae. The introduction of three gut bacterial isolates Enterococcus mundtii (PxG1), Carnobacterium maltaromaticum (PxCG2), and Acinetobacter guillouiae (PxCG3) restored sensitivity to Bt Cry1Ac protoxin. We also found that Cry1Ac protoxin and native gut microbiota can trigger host midgut immune response, which involves the up-regulation of expression of Toll and IMD pathway genes and most antimicrobial peptide genes, respectively. Our findings further shed light on the interplay between insect gut microbiota and host immunity under the Bt toxin killing pressure, and this may provide insights for improving the management of Bt resistance and lead to new strategies for biological control of insect pests.


Assuntos
Bacillus thuringiensis , Microbioma Gastrointestinal , Mariposas , Acinetobacter , Animais , Proteínas de Bactérias/genética , Carnobacterium , Endotoxinas/toxicidade , Enterococcus , Proteínas Hemolisinas , Imunidade , Proteínas de Insetos , Resistência a Inseticidas , Larva
8.
Ecotoxicol Environ Saf ; 208: 111647, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396167

RESUMO

Eurycomanone is a quassinoid compound that is derived from Eurycoma longifolia, and it is often used as an indicator to evaluate the active ingredients of Eurycoma longifolia. However, Eurycomanone has rarely been reported to have biological activity toward pests. In this study, we evaluated the antifeedant activity of eurycomanone against the diamondback moth(Plutella xylostella), with a non-selective AFC50(the concentration that corresponds to 50% antifeedant action) value and selective AFC50 of 17.5 mg/L and 14.2 mg/L, respectively, which were 2.1-fold (36.9 mg/L) and 2-fold (28.5 mg/L) lower than that of azadirachtin, respectively. In addition, eurycomanone was used to treat the roots of Brassica chinensis L. at a concentration of 100 µg/g for 72 h. The antifeedant index was found to reach 93% by tracking the leaves. After feeding with 20 µg/g eurycomanone, no pupae or eclosion were observed. To explore this mechanism, we used scanning electron microscopy to discover that eurycomanone could prevent the development of taste receptors on the maxillary palp of diamondback moth larvae. Additional electrophysiological measurements showed that eurycomanone exhibited excitatory action to the central taste neurons of diamondback moth and significantly inhibited the GABAA receptor current. Eurycomanone exhibited significant activity as an antifeedant, inhibited growth and excelled at systemic absorption.


Assuntos
Inseticidas/farmacologia , Hormônios Juvenis/farmacologia , Mariposas/crescimento & desenvolvimento , Extratos Vegetais/farmacologia , Quassinas/farmacologia , Animais , Brassica/parasitologia , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Folhas de Planta/parasitologia , Raízes de Plantas/parasitologia , Receptores de GABA-A/efeitos dos fármacos , Receptores de GABA-A/metabolismo
9.
Ecotoxicol Environ Saf ; 208: 111581, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396104

RESUMO

Lead (Pb) stress affects hormone-mediated responses (e.g., reproduction) in insects. In this study, the effects of Pb stress (12.5-50 mg Pb/kg in larval artificial diets) on the reproduction of the common cutworm Spodoptera litura (Lepidoptera: Noctuidae) were investigated after 7 generations. The results showed that Pb stress did not reduce the longevity of adult females, but 50 mg Pb/kg significantly reduced the longevity of adult males, regardless of the generation. After 50 mg Pb/kg stress for one or 7 generations, the peak time of egg-laying was delayed, and egg production and hatchability were decreased significantly. The vitellin content in eggs was significantly inhibited by Pb stress. The S. litura vitellogenin (Vg) gene promoter was cloned and analyzed. Multiple putative transcription factors were predicted for the 2321 bp Vg promoter region, including the TATA box, GATA, basic helix-loop-helix (bHLH) transcription factor, Broad-Complex (BR-C) binding sites, etc. The fragment from -2222 to -211 bp of the Vg promoter was the activation domain for Vg, whereas the region from -211 to -55 bp repressed the activity of the Vg promoter. The construct promoter (-782/+76) in Trichoplusia ni (Hi5) cells significantly improved Vg expression, which was not affected by Pb stress (1 or 10 mg/ml). Therefore, Pb stress significantly inhibited the reproduction of S. litura but not by regulating the Vg promoter.


Assuntos
Poluentes Ambientais/toxicidade , Chumbo/toxicidade , Spodoptera/fisiologia , Vitelogeninas/genética , Animais , Dieta , Poluentes Ambientais/metabolismo , Feminino , Larva/efeitos dos fármacos , Chumbo/metabolismo , Longevidade , Masculino , Mariposas , Oviposição/efeitos dos fármacos , Reprodução/efeitos dos fármacos , Spodoptera/efeitos dos fármacos , Vitelogeninas/metabolismo
10.
J Insect Sci ; 21(1)2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33428744

RESUMO

In this study, the complete mitochondrial genome of a white tussock moth, Laelia suffusa (Walker, 1855) (Lepidoptera: Erebidae, Lymantriinae), was sequenced and annotated. The genome sequence was 15,502 bp in length and comprised 13 PCGs, 2 rRNAs, 22 tRNAs, and a single noncoding control region (CR). The nucleotide composition of the genome was highly A + T biased, accounting for 79.04% of the whole genome and with a slightly positive AT skewness (0.015). Comparing the gene order with the basal species of Lepidoptera, a typical trnM rearrangement was detected in the mitogenome of L. suffusa. Besides, the trnM rearrangement was found at the head of trnI and trnQ, rather than at the back. The 13 PCGs used ATN as their start codons, except for the cox1 which used CGA. Out of the 22 tRNAs, only 1 tRNA (trnS1) failed to fold in a typical cloverleaf secondary structure. The conserved motif 'ATAGA + poly-T' was detected at the start of the control region which was similar to other Lepidoptera species. In total, 10 overlapping regions and 19 intergenic spacers were identified, ranging from 1 to 41 and 2 to 73 bp, respectively. Phylogenetic analysis showed that Lymantriinae was a monophyletic group with a high support value and L. suffusa was closely related to tribe Orgyiini (Erebidae, Lymantriinae). Moreover, the phylogenetic relationship of Noctuoidea (Lepidoptera) species was reconstructed using two datasets (13 PCGs and 37 genes) and these supported the topology of (Notodontidae + (Erebidae + (Nolidae + (Euteliidae + Noctuidae)))).


Assuntos
Genoma de Inseto , Genoma Mitocondrial , Mariposas/genética , Animais , Ordem dos Genes , Filogenia , Análise de Sequência de DNA
11.
Pest Manag Sci ; 77(1): 313-324, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33411414

RESUMO

BACKGROUND: The investigation of molecular mechanisms and evolution of resistance to insecticides is an ongoing challenge, as researchers must provide guidance to manage the resistance to achieve sustainable production in agriculture. Predicting, monitoring, and managing insecticide resistance requires information on the origins, selection, and spread of resistance genes. The resistance of Plutella xylostella (L.) against diamide insecticides is becoming an increasingly severe problem in east and southeast Asia. In this study, the evolution of resistance was investigated using a resistance allele [ryanodine receptor (RyR); G4946E mutation] and its flanking regions, as well as mitochondrial cytochrome c oxidase subunit I (mtCOI). RESULTS: The sequences of the flanking region of the G4946E and mtCOI suggested that the G4946E mutation has a key role in resistance. Furthermore, the G4946E mutation has multiple origins, and congenic resistant mutations have spread across east and southeast Asia, despite substantial geographical barriers. In addition, the susceptibility of field populations partially recovered during winter, based on the observed decrease in the G4946E (resistant allele) frequency. Finally, the resistance level indexed by the frequency of the E4946 allele was significantly lower in non-overwintering regions than in overwintering regions. CONCLUSION: The information of the present study is useful to monitor resistance using molecular markers and to develop strategies to delay the evolution of diamide resistance.


Assuntos
Inseticidas , Mariposas , Alelos , Animais , Ásia Sudeste , Diamida , Resistência a Inseticidas/genética , Inseticidas/farmacologia , Mariposas/genética
12.
Ecol Lett ; 24(2): 337-347, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33314559

RESUMO

Population cycles are fundamentally linked with spatial synchrony, the prevailing paradigm being that populations with cyclic dynamics are easily synchronised. That is, population cycles help give rise to spatial synchrony. Here we demonstrate this process can work in reverse, with synchrony causing population cycles. We show that timescale-specific environmental effects, by synchronising local population dynamics on certain timescales only, cause major population cycles over large areas in white-tailed deer. An important aspect of the new mechanism is specificity of synchronising effects to certain timescales, which causes local dynamics to sum across space to a substantial cycle on those timescales. We also demonstrate, to our knowledge for the first time, that synchrony can be transmitted not only from environmental drivers to populations (deer), but also from there to human systems (deer-vehicle collisions). Because synchrony of drivers may be altered by climate change, changes to population cycles may arise via our mechanism.


Assuntos
Cervos , Mariposas , Animais , Mudança Climática , Humanos , Dinâmica Populacional
13.
Chemosphere ; 266: 129235, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33316472

RESUMO

The use of nanoparticles in consumer products is currently on the rise, so it is important to have reliable methods to predict any associated toxicity effects. Traditional in vitro assays fail to mimic true physiological responses of living organisms against nanoparticles whereas murine in vivo models are costly and ethically controversial. For these reasons, this study aimed to evaluate the efficacy of Galleria mellonella as an alternative, non-rodent in vivo model for examining nanoparticle toxicity. Silver, selenium, and functionalized gold nanoparticles were synthesized, and their toxicity was assessed in G. mellonella larvae. The degree of acute toxicity effects caused by each type of NP was efficiently detected by an array of indicators within the larvae: LD50 calculation, hemocyte proliferation, NP distribution, behavioral changes, and histological alterations. G. mellonella larvae are proposed as a nanotoxicological model that can be used as a bridge between in vitro and in vivo murine assays in order to obtain better predictions of NP toxicity.


Assuntos
Nanopartículas Metálicas , Mariposas , Animais , Ouro , Larva , Dose Letal Mediana , Nanopartículas Metálicas/toxicidade , Camundongos
14.
Ecotoxicol Environ Saf ; 209: 111861, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33383338

RESUMO

Soybean pod borer (Leguminivora glycinivorella) is an important pest in soybean production, and chemical pesticides was major way for prevention. However, it is difficult to balance the efficiency and safety of pesticide application. In this paper, we evaluated safety and effectiveness of common insecticides (chlorpyrifos and lambda-cyhalothrin) on soybean from three aspects, including distribution, dissipation and control effect, around three major soybean production area (Anhui, Jilin and Shandong) in China. For chlorpyrifos, the initial deposition of each position (upper leaf, lower leaf, upper stem, lower stem, soybean and root) was determinated for 0.23 mg/kg to 70.7 mg/kg, and the half-lifes ranged from 1.96 days to 5.36 days. For lambda-cyhalothrin, the initial deposition of the position was determinated for 0.10 mg/kg to 2.54 mg/kg, and the half-lifes ranged from 2.45 days to 7.26 days. We found that the target insecticides were major deposition and faster degradation in upper stem and leaf. Through comparing the relationship between field control effect and residue, it can be suggested that 40% chlorpyrifos EC and 2.5% lambda-cyhalothrin WE should be sprayed at 600 g a.i./ha and 5.63 g a.i./ha for SPB prevention. This study enhanced our understanding of distribution, dissipation and relationship between residue and control effect. The results provided data support for guiding the precise and scientific application of chemical insecticides on soybean.


Assuntos
Clorpirifos/metabolismo , Inseticidas/metabolismo , Mariposas , Nitrilos/metabolismo , Piretrinas/metabolismo , Soja/metabolismo , Animais , China , Inseticidas/análise , Praguicidas/metabolismo , Folhas de Planta/química
15.
Pestic Biochem Physiol ; 171: 104720, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33357542

RESUMO

Chilo suppressalis Walker (Lepidoptera: Crambidae) is a widely destructive pest occurring in rice, particularly in the rice-growing regions of Asia. In recent years, C. suppressalis has developed resistance to several insecticides because of the extensive use of insecticides. The resistance levels to four insecticides were determined among populations from different regions of Sichuan Province, China, using a drop-method bioassay. Based on LC50 values of a laboratory susceptible strain, all field populations showed moderate level of resistance to triazophos (23.9- to 83.5-fold) and were either susceptible or had a low level of resistance to abamectin (2.1- to 5.8-fold). All field-collected populations had a low or moderate level of resistance to chlorpyrifos (1.7- to 47.1-fold) and monosultap (2.7- to 13.5-fold). The synergism experiment indicated that the resistance of the XW19 to triazophos may be associated with cytochrome P450 monooxygenases (P450s), with the highest synergistic ratio (SR) of 3.05-fold and increased ratio (IR) of 2.28-fold for piperonylbutoxide (PBO). The P450 activity of the TJ19 population was the greatest among the six field populations. Moreover, the relative expression levels of four resistance-related P450 genes were detected with qRT-PCR, and the results indicated that CYP324A12, CYP321F3 and CYP9A68 were overexpressed in the resistant population, especially in the XW19 population (by 1.2-, 3.4 -, and 18.0-fold, respectively). In addition, the relative expression levels of CYP9A68 among the CZ19 and TJ19 populations were also enhanced 10.5- and 24.9-fold, respectively. These results suggested that CYP324A12, CYP321F3 and CYP9A68 may be related to the resistance development of C. suppressalis to triazophos.


Assuntos
Clorpirifos , Inseticidas , Lepidópteros , Mariposas , Oryza , Animais , China , Clorpirifos/farmacologia , Resistência a Inseticidas/genética , Inseticidas/farmacologia , Mariposas/genética , Oryza/genética
16.
Pestic Biochem Physiol ; 171: 104726, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33357547

RESUMO

Insect antennae play a fundamental role in perceiving and recognizing a broad spectrum of conventional semiochemicals and host plant-derived odors. As such, genes that are tightly associated with the antennae are thought to have olfactory-related roles related to signal transduction mechanisms. Several mechanisms suggest that enzymatic inactivation could contribute to the signal termination process, such as odorant-degrading enzymes (ODEs). To date, a few ODEs have been identified and characterized in detail in insect herbivores, but little is known about aldehyde oxidases (AOXs); moreover, direct in vivo experimental evidence is needed. AOXs are a major family of metabolic enzymes that oxidize a variety of aromatic aldehydes, and they may also play a significant role in detoxification and degradation of environmental chemical cues. Here, we report on the identification and characterization of a novel cDNA encoding the putative odorant-degrading enzyme, PxylAOX3, from the antennae of the diamondback moth, (DBM), Plutella xylostella (L.) (Lepidoptera: Plutellidae). The purified recombinant protein showed a wide-range of substrate zymography oxidizing both sex pheromone compounds as well as plant-derived aldehydes with distinct activities. Our data suggest PxylAOX3 might be involved in the degradation of many structurally diverse aldehyde odorants. Furthermore, PxylAOX3 could participate in olfactory neuron protection by inactivation of redundant odorants and xenobiotic detoxification, making it a potential target for pesticide development as well.


Assuntos
Mariposas , Atrativos Sexuais , Aldeído Oxidase/genética , Animais , Mariposas/genética , Feromônios , Xenobióticos
17.
Pestic Biochem Physiol ; 171: 104730, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33357552

RESUMO

The inhibitory potential of an inhibitor peptide based on the pro-region of trypsin zymogen was investigated in Indianmeal moth, P. interpunctella, which is a world-wide insect pest of stored food. Five peptides were designed based on molecular docking simulations. The designed peptide with the best score was selected and synthesized for further screening in vitro and in vivo. The peptide was characterized and its inhibitory effects towards the insect trypsin were evaluated and the kinetic analysis revealed a competitive type of inhibition against the target enzyme. The results showed that the peptide could successfully suppress the pest midgut trypsin, and more interestingly, it did not show considerable inhibitory effects on a mammalian trypsin. We also aimed to assess the effect of dietary insect meal treated with different concentrations of the peptide and observed a significant growth and development retardation in pupa and adult insects fed with the inhibitor peptide. The outcomes of the present study suggest an efficient inhibitor peptide that could specifically bind the P. interpunctella trypsin and inhibit its activity, which would be safe against human being health and environment. Notably, this is the first report on in vivo assessment of the direct effect of a pro-region as the specific inhibitor in development as well as survival of the pest insect. Furthermore, our findings could be a promising for future designed pesticides used in pest management.


Assuntos
Mariposas , Inibidores da Tripsina , Animais , Cinética , Larva , Simulação de Acoplamento Molecular , Inibidores da Tripsina/toxicidade
18.
Pestic Biochem Physiol ; 171: 104732, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33357554

RESUMO

Beauveria bassiana is a promising biocontrol agent due to its entomopathogenic activities and residue-free characteristics. However, its susceptibility to abiotic stresses and naturally low virulence limit the effective application of this fungus. To effectively obtain fungal strains with high biocontrol potential, fluorescence-activated cell sorting (FACS) was used to screen mutant libraries generated by atmospheric and room temperature plasma (ARTP). Among about 8000 mutants obtained by ARTP mutagenesis, six candidate mutants were selected according to the forward scatter (FSC) signal readings of FACS. B6, with a 37.4% higher FSC reading than wild-type (WT), showed a 32.6% increase in virulence. It also presented a 13.5% decrease in median germinating time (GT50) and a 12.1% increase in blastospore production. Comparative analysis between insect transcriptional responses to B6 and WT infection showed that the immune response coupled with protein digestion and absorption progress was highly activated in B6-infected Galleria mellonella larvae, while fatty acid synthesis was suppressed after 3 days of infection. Our results confirmed the feasibility of sorting B. bassiana with high biocontrol potential via the combination of ARTP and FACS and facilitated the understanding of insect-pathogen interactions, highlighting a new strategy for modifying entomopathogenic fungi to improve the efficiency of biological control.


Assuntos
Beauveria , Mariposas , Animais , Citometria de Fluxo , Mutagênese , Plasma
19.
GM Crops Food ; 12(1): 1-17, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32762312

RESUMO

A biophysical survey was conducted in 15 cotton-growing districts of Pakistan. Four hundred cotton growers were approached and inquired about the production technology of Bt cotton. Further, 25 strip tests using combo strips (Cry1Ac, Cry2Ab, Vip3Aa and Cp4, EPSPS gene) were performed at each farmer's field. Out of 10,000 total-tested samples, farmers claimed 9682 samples as Bt and 318 samples as non-Bt. After performing a strip test, 1009 and 87 samples were found false negative and false positive, respectively. Only 53 samples were found positive for Cry2Ab, 214 for EPSPS and none for Vip3Aa gene. Quantification of Cry endotoxin and bioassay studies were performed by taking leaves from upper, middle, and lower canopies, and fruiting parts at approximately 80 days after sowing from 89 varieties. Expression was highly variable among different canopies and fruiting parts. Moreover, Cry endotoxin expression and insect mortality varied significantly among varieties from 0.26 µg g-1 to 3.54 µg g-1 with mortality ranging from 28 to 97%, respectively. Highest Cry1Ac expression (3.54 µg g-1) and insect mortality (97%) were observed for variety FH-142 from DG Khan. Cry endotoxin expression varied significantly across various plant parts, i.e., IUB-13 variety from upper canopy documented 0.34 µg g-1 expression with 37% insect mortality in Layyah to 3.42 µg g-1 expression and 96% insect mortality from DG Khan. Lethal dose, LD95 (2.20 µg g-1) of Cry1Ac endotoxin was optimized for effective control of H. armigera. Our results provided evidence of practical resistance in H. armigera and way forward.


Assuntos
Proteínas Hemolisinas/genética , Mariposas , Animais , Proteínas de Bactérias/genética , Endotoxinas , Gossypium , Resistência a Inseticidas , Larva , Paquistão , Plantas Geneticamente Modificadas
20.
Ecotoxicol Environ Saf ; 207: 111214, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32890949

RESUMO

The potential risk of Bt (Bacillus thuringiensis) crops on non-target organisms (NTOs) has drawn a lot of public concerns. Despite a series of risk assessments of Bt crops on NTOs has been conducted, a quantitative approach which could support a precise judgment of their safety is required. In the present work, hazard quotient (HQ) was applied in the safety evaluation of three Bt rice events (Cry1Ab, Cry1C and Cry2Aa rice) on NTOs. Eight NTOs in different functional guilds associated with Bt rice were selected to conduct the tests. The results showed that the HQs of three Bt rice events for eight NTOs were all below the trigger value 1, while the HQ of Cry1Ab rice for one target pest Chilo suppressalis was three times higher than 1. Our results assured the reliability of the HQ and indicated that the three Bt rice events would pose no risks to the eight NTOs. Further testing of three Bt proteins on biological parameters of one NTO Nasonia virtipennis under no observed adverse effect concentration (NOAEC) confirmed the robustness of HQ assessment. We recommend that the HQ could be applied in tier-1 risk assessments of Bt crops on NTOs as a reference data standard, which would provide more clear and credible safety information of transgenic crops for the public and policy makers.


Assuntos
/toxicidade , Endotoxinas/toxicidade , Proteínas Hemolisinas/toxicidade , Oryza/genética , Plantas Geneticamente Modificadas , Animais , Bacillus thuringiensis/genética , Proteínas de Bactérias/metabolismo , Produtos Agrícolas/metabolismo , Endotoxinas/metabolismo , Proteínas Hemolisinas/genética , Mariposas , Oryza/metabolismo , Controle Biológico de Vetores/métodos , Reprodutibilidade dos Testes
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