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1.
J Insect Sci ; 21(2)2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33834209

RESUMO

The aim of this review is to compile up-to-date information on the superworm, Zophobas morio (F.), regarding its biology and ecology, but also its further potential for use as a nutrient source for food and feed. We illustrate certain basic characteristics of the morphology and bio-ecology of this species, which is marginally considered as a 'pest' in durable amylaceous commodities. More recent data show that Z. morio can be a valuable nutrient and antimicrobial source that could be utilized further in insect-based feed and food production. The inclusion of this species in aquafeed has provided promising results in a wide range of feeding trials, both in terms of fish development and health. Additional data illustrate its potential for use in poultry, indicating that this species provides comparable results with those of other insect species that are used in feed. Moreover, Z. morio can be a viable waste management agent. This review aims to summarize the available data and underline data gaps for future research, toward the potential of the utilization of Z. morio for human food and animal feed. Based on the data presented, Z. morio appears to be a well-promising insect-based protein source, which potential still remains to be unfold.


Assuntos
Ração Animal , Tenebrio , Agricultura , Animais , Besouros/crescimento & desenvolvimento , Besouros/metabolismo , Proteínas de Insetos/metabolismo , Larva/crescimento & desenvolvimento , Larva/metabolismo , Nutrientes/metabolismo , Tenebrio/crescimento & desenvolvimento , Tenebrio/metabolismo
2.
Integr Zool ; 16(3): 313-323, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33704889

RESUMO

Insects' intestinal microbes have profound effects on the host's physiological traits, which can impact their physiology at both the local (gut) and systemic (body) levels. Nevertheless, the molecular mechanisms underlying host-microbiota interactions, especially in non-model insects, remain elusive. Recently, tissue-specific transcriptomic analysis has been highlighted as a robust tool in studying host-microbe interactions. Plagiodera versicolora is a worldwide leaf-eating pest that primarily feeds on willows and poplar. The interplay between gut microflora and this host beetle has yet to be studied. Herein, we investigate the effects of the gut microbiota on the body mass of P. versicolora larvae, compare the nutrition status of larvae in absence and presence of gut microbiota, and profile gut bacterial loads throughout its developmental larval stages. We then perform comparative transcriptomic analysis of gut and body tissues in axenic and non-axenic larvae. Finally, we confirm the expression patterns of representative genes in nutritional metabolism and immunity. Results show that weight growth is retarded in conventional larvae, with a concomitant increase of total bacterial load by the 5th development day, and germ-free larvae have a higher glucose content than conventional-reared larvae. Both nutritional and immunological analyses indicate that gut bacteria are a burden in the beetle's larval development. These findings elucidate the impacts of gut microbiota on P. versicolora, and provide insight into tissue-specific responses to gut microflora in this pest at the genetic level, boosting our understanding of the molecular mechanisms underlying host-microbe interactions in leaf beetles and beyond.


Assuntos
Besouros/microbiologia , Microbioma Gastrointestinal , Animais , Bactérias/genética , Peso Corporal , Besouros/crescimento & desenvolvimento , Besouros/imunologia , Besouros/metabolismo , Dieta , Perfilação da Expressão Gênica , Vida Livre de Germes , Hemolinfa/química , Larva/imunologia , Larva/metabolismo , Larva/microbiologia , RNA Ribossômico 16S/genética
3.
Arch Insect Biochem Physiol ; 106(4): e21784, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33719055

RESUMO

Blister beetles have medicinal uses for their defensive secretion cantharidin, which has curative effects on many cancers and other diseases. It was demonstrated that sexual dimorphism exists in the production of cantharidin between male and female adults. This study performed a de novo assembly of Epicauta tibialis transcriptomes and analyzed the differentially expressed genes (DEGs) between male and female adults to help to find genes and pathways associated with cantharidin biosynthesis. A total of 99,295,624 paired reads were generated, and more than 7 Gb transcriptome data for each sample were obtained after trimming. The clean data were used to de novo assemble and then cluster into 27,355 unigenes, with a mean length of 1442 bp and an N50 of 2725 bp. Of these, 14,314 (52.33%) unigenes were annotated by protein databases. Differential expression analysis identified 284 differentially expressed genes (DEGs) between male and female adults. Nearly 239 DEGs were up-regulated in male adults than in female adults, while 45 DEGs were down-regulated. The Kyoto Encyclopedia of Gene and Genomes pathway enrichment manifested that seven up-regulated DEGs in male adults were assigned to the terpenoid biosynthesis pathway, to which 19 unigenes were annotated. The DEGs in the terpenoid biosynthesis pathway between male and female adults may be responsible for the sexual dimorphism in cantharidin production. The up-regulated genes assigned to the pathway in male adults may play a significant role in cantharidin biosynthesis, and its biosynthesis process is probably via the mevalonate pathway. The results would be helpful to better understand and reveal the complicated mechanism of the cantharidin biosynthesis.


Assuntos
Cantaridina/metabolismo , Besouros/metabolismo , Caracteres Sexuais , Animais , Besouros/genética , Feminino , Perfilação da Expressão Gênica , Genoma de Inseto , Masculino , Terpenos/metabolismo , Transcriptoma/genética
4.
Pestic Biochem Physiol ; 173: 104782, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33771261

RESUMO

The cowpea weevil (Callosobruchus maculatus) is the main pest that attacks cowpea (Vigna unguiculata) seeds during storage, causing nutritional and economic losses in the cowpea crop. Thus, studies aiming to identify resistant cowpea cultivars have been developed. Chitin-binding proteins (CBP), such vicilins and chitinases, have been detected in seeds and related with the toxicity to insects. In this work, we investigated the presence of chitin-binding proteins in the partially resistant cowpea cv. BRS Xiquexique and evaluated their toxicity towards cowpea weevil. The CBP fraction was isolated by chitin affinity chromatography. CBP fraction showed, through 15% SDS PAGE, protein bands with varying molecular masses, mainly below 55 kDa. Proteins present in CBP fraction were identified by Western blotting and mass spectrometry analysis, as vicilins and chitinases. CBP fraction, at 5%, was able to interfere with the development of cowpea weevil, decreasing larval mass and length. A CBV (chitin-binding vicilin) fraction isolated from CBP fraction was toxic, at 2.0%, to C. maculatus, decreasing larval mass and length in 64.3% and 33.23%, respectively. These results suggest that chitin binding proteins, such vicilins and chitinases, may be related to the resistance of cowpea cv. BRS Xiquexique to the infestation by C. maculatus.


Assuntos
Besouros , Vigna , Gorgulhos , Animais , Proteínas de Transporte , Quitina/metabolismo , Besouros/metabolismo , Proteínas de Plantas/metabolismo , Sementes/metabolismo , Vigna/metabolismo , Gorgulhos/metabolismo
5.
Pestic Biochem Physiol ; 173: 104770, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33771270

RESUMO

Chitin deacetylases (CDAs, EC 3.5.1.41) catalyze the N-deacetylation of chitin to produce chitosan, which is essential for insect survival. Hence, CDAs are promising targets for the development of novel insecticidal drugs. In this study, the putative Group I chitin deacetylase genes HpCDA1, HpCDA2-1 and HpCDA2-2 were identified from Holotrichia parallela. Conserved domain database search identified a chitin-binding peritrophin-A domain (ChBD), a low-density lipoprotein receptor class A domain (LDLa), and a putative CDA-like catalytic domain. RT-qPCR analysis showed that the Group I HpCDAs were expressed in various tissues and predominant in the integument. The developmental expression patterns from the first-instar to third-instar larvae showed that HpCDAs were highly expressed on the first day and gradually declined after molting. The functional characteristics of the Group I CDAs in cuticle organization were examined using RNA interference (RNAi) and transmission electron microscopy (TEM) methods. Administration of double-stranded HpCDA (dsHpCDA) through larval injection could suppress the expression levels of HpCDA1 and HpCDA2, thus resulting in abnormal or lethal phenotypes. TEM analysis revealed that RNAi of either HpCDA1 or HpCDA2 remarkably affected the cuticle integrity, as evidenced by cuticle disorganization and chitin laminae disruption, suggesting the crucial role of CDAs in chitin modification. These experimental results demonstrate the important contribution of putative key genes involved in chitin metabolism, and provide a foundation for developing new strategies to control H. parallela.


Assuntos
Besouros , Amidoidrolases/genética , Amidoidrolases/metabolismo , Animais , Quitina/metabolismo , Besouros/genética , Besouros/metabolismo , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Interferência de RNA
6.
Int J Biol Macromol ; 168: 350-355, 2021 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-33310101

RESUMO

Colorado potato beetle is an invasive insect herbivore and one of the most challenging agricultural pests globally. This study is the first characterization of the active centre of Colorado potato beetle (Leptinotarsa decemlineata) α-amylase (LdAmy). Bond cleavage frequency values for LdAmy were determined by HPLC product analysis on a chromophore labelled maltooligomer substrate series. Binding energies between amino acid moieties of subsites and glucose residues of substrate were calculated. Active site contains six subsites in the binding region of LdAmy; four glycone- (-4, -3, -2, -1) and two aglycone-binding sites (+1, +2). Subsite map calculation resulted in apparent binding energies -11.8 and - 11.0 kJ/mol for subsites (+2) and (-3), respectively, which revealed very favorable interactions at these positions. Structures of binding sites of LdAmy and mammalian α-amylases show similarity, but there are variations in the binding energies at subsite (-2) and (-4). Differences were interpreted by comparison of amino acid sequences of human salivary α-amylase (HSA) and porcine pancreatic α-amylase (PPA) and two insect (Leptinotarsa decemlineata and Tenebrio molitor) enzymes. The observed substitution of positively charged His305 in HSA at subsite (-2) with an acidic Asp in LdAmy in the same position may explain the obtained energy reduction.


Assuntos
Besouros/enzimologia , alfa-Amilases/isolamento & purificação , alfa-Amilases/metabolismo , Sequência de Aminoácidos/genética , Animais , Sítios de Ligação/genética , Domínio Catalítico/genética , Besouros/metabolismo , Humanos , Hidrólise , Ligação Proteica/genética , Homologia de Sequência de Aminoácidos , Especificidade por Substrato/genética , Suínos/genética , Tenebrio/genética , alfa-Amilases/genética
7.
Chemosphere ; 262: 127818, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32771707

RESUMO

Yellow mealworms (Tenebrio molitor larvae) are capable of biodegrading polystyrene (PS) and low-density polyethylene (LDPE). This study tested biodegradation of one expanded PS (EPS) with a weight-average molecular weight (Mw) 256.4 kDa and two LDPE foams with respective Mw of 130.6 kDa (PE-1) and 288.7 kDa (PE-2) in T. monitor larvae obtained in Beijing, China. The larvae consumed EPS and both LDPEs over a 60 day. Fourier transform infrared spectroscopy and thermogravimetric analyses of frass confirmed the formation of new oxygen-containing functional groups, as well as a change in physical property and chemical modification, indicating that biodegradation of EPS and LDPE occurred. Gel permeation chromatography analysis confirmed broad depolymerization of EPS and PE-1 (i.e., a decrease in both Mw and a number-average molecular weight (Mn)) but revealed limited extent depolymerization of PE-2 (i.e., increase in Mn and decrease in Mw). For all materials, the size-average molecular weight (Mz) was decreased. Biodegradation and oxidation of EPS and LDPE were confirmed using FTIR and TGA analysis. Depression of gut microbes by the antibiotic gentamicin resulted in significant inhibition of EPS depolymerization but did not stop LDPE depolymerization, resulting in the increase in Mn and revealing that PS biodegradation was gut microbe-dependent but LDPE biodegradation was less dependent or independent of gut microbes. Gut microbial community analysis indicated that, as expected, under different dietary conditions, the intestinal flora significantly shifted to communities associated with biodegradation of EPS and LDPE. The results indicated the complexity and limitation of biodegradation of plastics in plastics-eating T. molitor larvae.


Assuntos
Biodegradação Ambiental , Besouros/metabolismo , Poliestirenos/metabolismo , Tenebrio/metabolismo , Animais , Antibacterianos/metabolismo , Pequim , China , Cromatografia em Gel , Microbioma Gastrointestinal , Gentamicinas , Larva/metabolismo , Plásticos/metabolismo , Polietileno/metabolismo , Espectroscopia de Infravermelho com Transformada de Fourier
8.
Food Chem ; 338: 128073, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-32950872

RESUMO

Protein digestibility of Protaetia brevitarsis larvae before and after defatting by hexane was compared with that of beef loin in an in vitro digestion model. Larvae had higher crude protein content and 10% trichloroacetic acid (10% TCA)-soluble α-amino groups than beef. Decreases in the levels of total free sulfhydryl groups and 10% TCA-soluble α-amino groups were detected in larvae and beef after defatting (P < 0.05). Surface hydrophobicity increased after defatting in both larvae and beef, (P < 0.05) and tryptophan fluorescence intensity decreased in defatted larvae but increased in defatted beef. Levels of proteins digested into sizes under 3 and 10 kDa in larvae were higher than those in beef (P < 0.05), and defatting did not induce an effect in larvae. Therefore, in the aspect of high protein content and digestibility, larvae of P. brevitarsis can be a potential substitute of animal proteins.


Assuntos
Besouros/metabolismo , Proteínas de Insetos/metabolismo , Carne/análise , Proteínas/metabolismo , Animais , Bovinos , Besouros/crescimento & desenvolvimento , Digestão , Hexanos/química , Larva/metabolismo , Compostos de Sulfidrila/análise
9.
Molecules ; 25(24)2020 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-33371481

RESUMO

The osteogenic differentiation of stem cells is profoundly affected by their microenvironmental conditions. The differentiation behavior of stem cells can be tuned by changing the niche environments. The proteins or peptides that are derived by living organisms facilitate the osteogenic differentiation of stem cells. Here, we have evaluated the osteoinductive and antioxidative potential of the Protaetia brevitarsis seulensis insect-derived protein for human bone marrow-derived mesenchymal stem cells (hBMSCs). The amino acid contents in the isolated protein were determined by an amino acid analyzer. Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) were used to analyze the extract's functional groups and surface morphology. The extracted protein exhibited 51.08% ß-sheet conformation. No adverse effects were observed in extract-treated cells, indicating their biocompatibility. The protein isolate showed an excellent antioxidative property. Besides this, an enhancement in the hBMSCs' mineralization has been observed in the presence of treated protein isolates. Notably, osteogenic marker genes and proteins were effectively expressed in the treated cells. These results indicated that the P. brevitarsis-derived protein isolate can be used as a potential antioxidative biomaterial for bone tissue engineering applications.


Assuntos
Antioxidantes/metabolismo , Besouros/metabolismo , Proteínas de Insetos/metabolismo , Aminoácidos/metabolismo , Animais , Osso e Ossos/metabolismo , Osso e Ossos/fisiologia , Diferenciação Celular/fisiologia , Linhagem Celular , Humanos , Larva/metabolismo , Células-Tronco Mesenquimais/metabolismo , Células-Tronco Mesenquimais/fisiologia , Microscopia Eletrônica de Varredura/métodos , Osteogênese/fisiologia , Peptídeos/metabolismo , Conformação Proteica em Folha beta/fisiologia , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Engenharia Tecidual/métodos
10.
PLoS One ; 15(12): e0235028, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33362256

RESUMO

Cyclocephalini beetles of the genus Cyclocephala (Coleoptera: Melolonthidae: Dynastinae) use flowers of some plants as food, shelter, and mating sites. However, little is known about floral scent chemistry involved in this interaction. Here we show that a sesquiterpene alcohol mediates attraction of Cyclocephala paraguayensis Arrow, on bottle gourd flowers, Lagenaria siceraria (Cucurbitaceae). Both males and females started to aggregate on the flowers at twilight; after that, mating began and remained for the entire night. GC-FID/EAD analysis of the L. siceraria floral scent collected in the field revealed that only the major constituent of the airborne volatiles elicited electroantennographic responses on male and female antennae of C. paraguayensis. This compound was identified as (3S,6E)-nerolidol, which was tested in two field trapping trials in Brazil. In the first bioassay, traps baited with nerolidol (mix of isomers) captured significantly more adult C. paraguayensis than control traps. In the second field trial, catches in traps baited with a mixture of isomers or enantiopure nerolidol were significantly higher than captures in control traps, but the treatments did not differ significantly. Analysis from the gut content of adult C. paraguayensis showed the presence of pollen, suggesting that they also use bottle gourd flowers for their nourishment. Taken together, these results suggest that (3S,6E)-nerolidol plays an essential role in the reproductive behavior of C. paraguayensis by eliciting aggregation, mating, and feeding.


Assuntos
Besouros/fisiologia , Cucurbita/metabolismo , Sesquiterpenos/metabolismo , Animais , Brasil , Besouros/metabolismo , Cucurbita/fisiologia , Cucurbitaceae/metabolismo , Cucurbitaceae/fisiologia , Feminino , Flores/fisiologia , Masculino , Odorantes/análise , Feromônios/análise , Pólen/fisiologia , Polinização , Sesquiterpenos/análise
11.
Int J Mol Sci ; 22(1)2020 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-33375157

RESUMO

Dendroctonus-bark beetles are natural agents contributing to vital processes in coniferous forests, such as regeneration, succession, and material recycling, as they colonize and kill damaged, stressed, or old pine trees. These beetles spend most of their life cycle under stem and roots bark where they breed, develop, and feed on phloem. This tissue is rich in essential nutrients and complex molecules such as starch, cellulose, hemicellulose, and lignin, which apparently are not available for these beetles. We evaluated the digestive capacity of Dendroctonusrhizophagus to hydrolyze starch. Our aim was to identify α-amylases and characterize them both molecularly and biochemically. The findings showed that D. rhizophagus has an α-amylase gene (AmyDr) with a single isoform, and ORF of 1452 bp encoding a 483-amino acid protein (53.15 kDa) with a predicted signal peptide of 16 amino acids. AmyDr has a mutation in the chlorine-binding site, present in other phytophagous insects and in a marine bacterium. Docking analysis showed that AmyDr presents a higher binding affinity to amylopectin compared to amylose, and an affinity binding equally stable to calcium, chlorine, and nitrate ions. AmyDr native protein showed amylolytic activity in the head-pronotum and gut, and its recombinant protein, a polypeptide of ~53 kDa, showed conformational stability, and its activity is maintained both in the presence and absence of chlorine and nitrate ions. The AmyDr gene showed a differential expression significantly higher in the gut than the head-pronotum, indicating that starch hydrolysis occurs mainly in the midgut. An overview of the AmyDr gene expression suggests that the amylolytic activity is regulated through the developmental stages of this bark beetle and associated with starch availability in the host tree.


Assuntos
Besouros/metabolismo , Trato Gastrointestinal/metabolismo , Pinus/parasitologia , Casca de Planta/parasitologia , Amido/metabolismo , alfa-Amilases/metabolismo , Amilopectina/metabolismo , Amilose/metabolismo , Animais , Ligação Competitiva , Besouros/enzimologia , Besouros/genética , Trato Gastrointestinal/enzimologia , Regulação Enzimológica da Expressão Gênica , Hidrólise , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Ligação Proteica , alfa-Amilases/genética
12.
PLoS One ; 15(8): e0238057, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32845917

RESUMO

Arthropods are a major soil fauna group, and have the potential to substantially influence the spatial and temporal variability of soil greenhouse gas (GHG) sinks and sources. The overall effect of soil-inhabiting arthropods on soil GHG fluxes still remains poorly quantified since the majority of the available data comes from laboratory experiments, is often controversial, and has been limited to a few species. The main objective of this study was to provide first insights into field-level carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) release of soil-inhabiting larvae of the Scarabaeidae family. Larvae of the genus Melolontha were excavated at various sites in west-central and southern Germany, covering a wide range of different larval developmental stages, larval activity levels, and vegetation types. Excavated larvae were immediately incubated in the field to measure their GHG production. Gaseous carbon release of individual larvae showed a large inter- and intra-site variability which was strongly correlated to larval biomass. This correlation persisted when upscaling individual CO2 and CH4 production to the plot scale. Field release estimates for Melolontha spp. were subsequently upscaled to the European level to derive the first regional GHG release estimates for members of the Scarabaeidae family. Estimates ranged between 10.42 and 409.53 kt CO2 yr-1, and 0.01 and 1.36 kt CH4 yr-1. Larval N2O release was only sporadically observed and not upscaled. For one site, a comparison of field- and laboratory-based GHG production measurements was conducted to assess potential biases introduced by transferring Scarabaeidae larvae to artificial environments. Release strength and variability of captive larvae decreased significantly within two weeks and the correlation between larval biomass and gaseous carbon production disappeared, highlighting the importance of field measurements. Overall, our data show that Scarabaeidae larvae can be significant soil GHG sources and should not be neglected in soil GHG flux research.


Assuntos
Besouros/metabolismo , Gases de Efeito Estufa/análise , Animais , Biomassa , Dióxido de Carbono/análise , Dióxido de Carbono/metabolismo , Besouros/química , Besouros/crescimento & desenvolvimento , Gases de Efeito Estufa/metabolismo , Larva/química , Larva/metabolismo , Metano/análise , Metano/metabolismo , Óxido Nitroso/análise , Óxido Nitroso/metabolismo , Solo/química , Solo/parasitologia
13.
Chemosphere ; 259: 127497, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32650168

RESUMO

Heavy metal pollution is an increasingly serious problem in agricultural ecosystems. Zinc accumulation in the food chain may harm the physiological functions of organisms, including herbivorous and predatory insects. Its effects on development and reproduction in Harmonia axyridis are largely unknown. In this study, five Zn solutions (25, 50, 100, and 150 mg/kg) plus control (0 mg/kg) were used to treat broad beans and to water the resulting seedlings. Aphids fed on these seedlings were eaten by H. axyridis ladybugs. Zn accumulation was found at all three trophic levels. Compared with the control group, ladybugs in the 25, 50, and 100 mg/kg groups had significantly reduced weight gain from the 4th instar to adulthood. Pupae and larvae (instars 1-4) in the 150 mg/kg group had the lowest survival of any group; pupal mortality in the 100 mg/kg group was significantly higher than that in the control group. Under Zn stress, female adults had inhibited expression of Vg1, Vg2 and VgR, reducing egg production and hatchability. Zn thus negatively affected their fertility. These results provide a theoretical basis for future exploration of soil heavy metal pollution impacts in ecosystems.


Assuntos
Afídeos/química , Besouros/efeitos dos fármacos , Poluentes Ambientais/farmacologia , Fertilidade/efeitos dos fármacos , Cadeia Alimentar , Zinco/farmacologia , Animais , Afídeos/metabolismo , Besouros/crescimento & desenvolvimento , Besouros/metabolismo , Besouros/fisiologia , Relação Dose-Resposta a Droga , Poluentes Ambientais/metabolismo , Feminino , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Masculino , Metais Pesados/metabolismo , Metais Pesados/farmacologia , Plantas Comestíveis/química , Plantas Comestíveis/parasitologia , Reprodução/efeitos dos fármacos , Zinco/metabolismo
14.
Chemosphere ; 258: 127254, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32559492

RESUMO

Glyphosate is the most used herbicide worldwide, targeting physiological pathways in plants. Recent studies have shown that glyphosate can also cause toxic effects in animals. We investigated the glyphosate-based herbicide (GBH)-induced changes in potato (Solanum tuberosum) plant chemistry and the effects of a GBH on the survival rate and oxidative status of the Colorado potato beetle (Leptinotarsa decemlineata). The beetles were reared on potato plants grown in pots containing soil treated with a GBH (Roundup Gold, 450 g/l) or untreated soil (water control). The 2nd instar larvae were introduced to the potato plants and then collected in 2 phases: as 4th instar larvae and as adults. The main glycoalkaloids of the potato plants, α-solanine and α-chaconine, were measured twice during the experiment. The α-solanine was reduced in potato plants grown in GBH-treated soil, which can be detrimental to plant defenses against herbivores. GBH treatment had no effect on the survival rate or body mass of the larvae or the adult beetles. In the larvae, total glutathione (tGSH) concentration and the enzyme activity of catalase (CAT), superoxide dismutase, and glutathione-S-transferase were increased in the GBH treatment group. In the adult beetles, CAT activity and tGSH levels were affected by the interactive effect of GBH treatment and the body mass. To conclude, environmentally relevant concentrations of a GBH can affect the potato plant's glycoalkaloid concentrations, but are not likely to directly affect the survival rate of the Colorado potato beetle, but instead, modify the antioxidant defense of the beetles via diet.


Assuntos
Besouros/efeitos dos fármacos , Glicina/análogos & derivados , Herbicidas/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Solo/química , Solanum tuberosum/efeitos dos fármacos , Animais , Antioxidantes/metabolismo , Besouros/metabolismo , Glutationa Transferase/metabolismo , Glicina/toxicidade , Larva/efeitos dos fármacos , Larva/metabolismo , Oxirredução , Solanina/análogos & derivados , Solanina/metabolismo , Solanum tuberosum/crescimento & desenvolvimento , Solanum tuberosum/metabolismo
15.
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
16.
J Chem Ecol ; 46(4): 378-386, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32240481

RESUMO

Before weed biocontrol insects are transported and released in a new area, they are commonly collected into small paper containers, chilled, and kept under dark conditions. This process can be termed a pre-release protocol. The influence of a pre-release protocol on establishment success of a gregarious biological control agent was assessed using the northern tamarisk beetle, Diorhabda carinulata (Desbrochers), and its exotic, invasive host plant saltcedar (Tamarix spp.). Pre-release protocol impacts on aggregation pheromone production by D. carinulata were characterized under controlled conditions. Additional experiments were undertaken to determine if deployment of aggregation pheromone lures might enhance the agent's persistence at release sites. Adults that experienced the pre-release protocol produced less aggregation pheromone compared to undisturbed adults. Olfactometer bioassays indicated that a cohort of adults subjected to the pre-release protocol were less attractive to other adults than a control cohort. Efficacy of aggregation pheromone-based lures to retain adults at release sites was evaluated by comparing capture numbers of adult beetles at paired treatment and control release sites, 10-14 days after the release of 300, 500, or 1000 individuals. A greater number of adult D. carinulata were captured where the pheromone lures had been deployed compared to control release sites. Application of aggregation pheromone when a new release of D. carinulata is planned should allow biological control practitioners to increase retention of beetles at a release site.


Assuntos
Besouros/fisiologia , Controle Biológico de Vetores , Feromônios/metabolismo , Tamaricaceae , Controle de Plantas Daninhas , Animais , Besouros/metabolismo , Espécies Introduzidas , Dinâmica Populacional
17.
PLoS One ; 15(3): e0230435, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32191747

RESUMO

Harmonia axyridis is a major bio-control agent of pests in agriculture and forest ecosystems. It is also a globally important invasive insect species. To test whether dark elytra colour is associated with greater cold hardiness, we compared the survival rate of prolonged cold exposure in both yellow and black colour morphs of female and male H. axyridis. We determined the trehalose and glycogen content, trehalase activity, and the dynamics of genes associated with the trehalose metabolic pathway. Yellow forms predominated before winter began, however black forms increased from 11.15 to 30.46% after overwintering. There was no significant difference in trehalose content between the females and males during overwintering. Glycogen content in over-wintering yellow females and black males increased significantly, while it decreased in black females. Soluble trehalase activity increased significantly in all the insects except black females. Membrane-bound trehalase activity increased in black males, and decreased in black females. Trehalose and glycogen content and trehalase activity were regulated by differential expression of TRE and TPS genes. Female beetles weighed more than males and survived in low temperatures for longer periods of time, regardless of elytra colour, suggesting that mass is a stronger predictor of overwintering survival rather than colour morph. Our results provide a guide for comparing cold resistance in insects and a theoretical basis for cold storage of H. axyridis for use as natural enemies of pests in biological control programs.


Assuntos
Temperatura Baixa , Besouros/anatomia & histologia , Besouros/metabolismo , Estações do Ano , Trealose/metabolismo , Animais , Peso Corporal , Besouros/genética , Feminino , Regulação da Expressão Gênica , Genes de Insetos , Glicogênio/metabolismo , Masculino , Fenótipo , Análise de Sobrevida , Fatores de Tempo , Trealase/metabolismo
18.
Int J Mol Sci ; 21(6)2020 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-32197465

RESUMO

Melanization is a common phenomenon in insects, and melanin synthesis is a conserved physiological process that occurs in epidermal cells. Moreover, a comprehensive understanding of the mechanisms of melanin synthesis influencing insect pigmentation are well-suited for investigating phenotype variation. The Asian multi-colored (Harlequin) ladybird beetle, Harmonia axyridis, exhibits intraspecific polymorphism based on relative levels of melanization. However, the specific characteristics of melanin synthesis in H. axyridis remains elusive. In this study, we performed gene-silencing analysis of the pivotal inverting enzyme, tyrosine hydroxylase (TH), and DOPA decarboxylase (DDC) in the tyrosine metabolism pathway to investigate the molecular and regulatory mechanism of melanin synthesis in H. axyridis. Using RNAi of TH and DDC genes in fourth instar larvae, we demonstrated that dopamine melanin was the primary contributor to the overall body melanization of H. axyridis. Furthermore, our study provides the first conclusive evidence that dopamine serves as a melanin precursor for synthesis in the early pupal stage. According to transcription factor Pannier, which is essential for the formation of melanic color on the elytra in H. axyridis, we further demonstrated that suppression of HaPnr can significantly decrease expression levels of HaTH and HaDDC. These results in their entirety lead to the conclusion that transcription factor Pannier can regulate dopamine melanin synthesis in the dorsal elytral epidermis of H. axyridis.


Assuntos
Besouros , Regulação da Expressão Gênica/fisiologia , Proteínas de Insetos , Melaninas , Animais , Besouros/genética , Besouros/metabolismo , Proteínas de Insetos/biossíntese , Proteínas de Insetos/genética , Melaninas/biossíntese , Melaninas/genética
19.
Ecotoxicol Environ Saf ; 192: 110292, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32035396

RESUMO

The ladybeetle Propylea japonica is a widely distributed natural enemy in many agricultural systems. P. japonica is often used as a test organism for safety assessments of transgenic Bacillus thuringiensis crops. Plant varieties expressing the Vip3Aa insecticidal protein are not currently commercially available in China. In this study, protease inhibitor E-64 was used as a positive control to examine the responses of P. japonica larvae to a high concentration of Vip3Aa proteins. Larvae that were fed E-64 had increased mortality and prolonged developmental period, but these parameters were unaffected when larvae were fed Vip3Aa. The epithelial cells of midguts were intact and closely connected with the basal membrane when larvae were fed Vip3Aa, but the epithelial cells degenerated in the E-64 treatment. The activities of antioxidative enzymes and expression levels of detoxification-related genes in P. japonica larvae were not altered after exposure to Vip3Aa; however, these biochemical and molecular parameters were significantly changed in the E-64 treatment. The results demonstrate that Vip3Aa protein is not harmful to the predator P. japonica.


Assuntos
Proteínas de Bactérias/toxicidade , Besouros/efeitos dos fármacos , Inseticidas/toxicidade , Animais , China , Besouros/genética , Besouros/metabolismo , Larva/efeitos dos fármacos , Larva/enzimologia , Larva/genética , Larva/metabolismo
20.
Sci Rep ; 10(1): 1534, 2020 01 30.
Artigo em Inglês | MEDLINE | ID: mdl-32001773

RESUMO

Altica deserticola (Coleoptera: Chrysomelidae) is a monophagous insect that feeds on, and is thus a harmful pest of, liquorice. Both adults and larvae feed on leaves, causing serious damage to leaf blades. It will even lead to the extinction of liquorice, resulting in significant economic losses. Leaf-disc tests were used to determine the feeding preference of A. deserticola on leaves of Glycyrrhiza uralensis and G. glabra and explore the underlying mechanism of liquorice feeding resistance to A. deserticola by comparing leaf hardness and thickness, cuticle thickness, and nitrogen and tannin content in the two plants. The results showed that larvae and adults have the same feeding preferences, i.e., both preferably fed on G. uralensis, indicating a higher resistance in this species. The hardness, thickness, and the thickness of the stratum corneum of the leaves of G. glabra were significantly greater than those of G. uralensis. Nitrogen content was higher in G. uralensis, while total tannin, tannic acid, and catechin content were higher in G. glabra. The thick cuticle and hard texture of G. glabra leaves may be an important physical trait for effectively resisting A. deserticola feeding, while high tannin and low nitrogen content may also be important.


Assuntos
Besouros/metabolismo , Comportamento Alimentar/fisiologia , Folhas de Planta/metabolismo , Animais , Dieta , Glycyrrhiza/metabolismo , Glycyrrhiza/parasitologia , Glycyrrhiza uralensis/metabolismo , Glycyrrhiza uralensis/parasitologia , Folhas de Planta/química
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