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1.
J Chem Ecol ; 46(2): 186-197, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31953704

RESUMO

The horseradish flea beetle Phyllotreta armoraciae exclusively feeds on Brassicaceae, which contain glucosinolates as characteristic defense compounds. Although glucosinolates are usually degraded by plant enzymes (myrosinases) to toxic isothiocyanates after ingestion, P. armoraciae beetles sequester glucosinolates. Between and within brassicaceous plants, the glucosinolate content and composition can differ drastically. But how do these factors influence sequestration in P. armoraciae? To address this question, we performed a five-day feeding experiment with three Arabidopsis thaliana lines that differ four-fold in glucosinolate content and the composition of aliphatic and indolic glucosinolates. We quantified the amounts of ingested, sequestered, and excreted glucosinolates, and analyzed the changes in glucosinolate levels and composition in beetles before and after feeding on Arabidopsis. P. armoraciae accumulated almost all ingested glucosinolate types. However, some glucosinolates were accumulated more efficiently than others, and selected glucosinolates were modified by the beetles. The uptake of new glucosinolates correlated with a decrease in the level of stored glucosinolates so that the total glucosinolate content remained stable at around 35 nmol/mg beetle fresh weight. Beetles excreted previously stored as well as ingested glucosinolates from Arabidopsis, which suggests that P. armoraciae regulate their endogenous glucosinolate level by excretion. The metabolic fate of ingested glucosinolates, i.e. the proportions of sequestered and excreted glucosinolates, depended on glucosinolate type, content, and composition in the food plant. Overall, P. armoraciae sequestered and excreted up to 41% and 31% of the total ingested aliphatic and indolic glucosinolates from Arabidopsis, respectively. In summary, we show that glucosinolate variability in Brassicaceae influences the composition but not the level of sequestered glucosinolates in P. armoraciae beetles.


Assuntos
Brassicaceae/química , Besouros/metabolismo , Glucosinolatos/metabolismo , Animais , Arabidopsis/química , Arabidopsis/metabolismo , Brassicaceae/metabolismo , Fezes/química , Glucosinolatos/química , Hemolinfa/química , Hemolinfa/metabolismo , Interações Hospedeiro-Parasita
2.
J Chem Ecol ; 46(1): 30-39, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31808075

RESUMO

Cerambycid beetles of the subfamily Lamiinae use male-produced aggregation-sex pheromones that are attractive to both sexes. Terpenoid pheromones have been identified from species in the tribes Acanthoderini and Acanthocinini native to North and South America, comprised of (E)-6,10-dimethyl-5,9-undecadien-2-one (geranylacetone), the structurally related 6-methylhept-5-en-2-one (sulcatone), and/or specific enantiomers or nonracemic ratios of enantiomers of the related compounds (E)-6,10-dimethyl-5,9-undecadien-2-ol (fuscumol), its acetate ester, (E)-6,10-dimethyl-5,9-undecadien-2-yl acetate (fuscumol acetate), and 6-methylhept-5-en-2-ol (sulcatol). Here, we present new information about the chemical ecology of six acanthoderine and acanthocinine species native to the eastern USA. The pheromone of Astyleiopus variegatus (Haldeman) previously was identified as a blend of (S)-fuscumol and (S)-fuscumol acetate, and we report here that geranylacetone is a synergistic component. Males of Aegomorphus modestus (Gyllenhal), Lepturges angulatus (LeConte), and Lepturges confluens (Haldeman) were found to produce similar blends composed of the enantiomers of fuscumol acetate and geranylacetone, whereas males of Astylidius parvus (LeConte) and Sternidius alpha (Say) produced both enantiomers of fuscumol together with (R)-fuscumol acetate and geranylacetone. Field experiments with synthesized chemicals revealed that species with similar pheromone composition nevertheless differed in their responses to individual components, and to various blends of components, and in how attraction was influenced by chemicals that were pheromone components of other species. Sulcatone and/or sulcatol antagonized attraction of some species to pheromones of the geranylacetone class, suggesting that there is an adaptive advantage in an ability to detect these heterospecific compounds, such as in avoiding cross attraction to other cerambycid species, as yet unknown, that use pheromones composed of both chemical classes.


Assuntos
Besouros/química , Feromônios/química , Animais , Besouros/metabolismo , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Masculino , Feromônios/isolamento & purificação , Feromônios/farmacologia , Comportamento Sexual Animal/efeitos dos fármacos , Especificidade da Espécie , Estereoisomerismo , Terpenos/química , Terpenos/isolamento & purificação , Terpenos/farmacologia , Compostos Orgânicos Voláteis/química , Compostos Orgânicos Voláteis/isolamento & purificação , Compostos Orgânicos Voláteis/farmacologia
3.
Ecotoxicol Environ Saf ; 190: 110129, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31884327

RESUMO

Profenofos insecticide is one of the most broadly used organophosphorus pesticides causing the contamination of soil and groundwater. Since dissolved oxygen concentration in groundwater is limited, this study aimed to investigate profenofos biodegradation and detoxification under aerobic and anoxic conditions using the profenofos-degrading Pseudomonas plecoglossicida strain PF1 (PF1). Anoxic biodegradation under the presence of nitrate was the focus. The results showed that profenofos at 10-150 mg/L was degraded under aerobic and anoxic conditions with removal efficiencies of 38-55% and 27-45%, respectively. Kinetic analysis following the Michaelis-Menten model revealed that the maximum substrate degradation rates and the Michaelis constants were 13.07 and 8.92 mg/L/d and 92.07 and 84.76 mg/L under aerobic and anoxic conditions, respectively. The culture preferred an aerobic environment resulting in better biodegradation performance. During the degradation experiment, 4-bromo-2-chlorophenol and 1,1-dimethylethylphenol were detected as profenofos biodegradation intermediate products. Microbial toxicity, phytotoxicity, and cytogenotoxicity assays showed that the toxicity of the contaminated water significantly decreased after both aerobic and anoxic biodegradation by PF1. The results from this study indicated that PF1 has the potential for bioremediation in a profenofos-contaminated environment under the presence or absence of oxygen.


Assuntos
Biodegradação Ambiental , Inseticidas/metabolismo , Organotiofosfatos/metabolismo , Pseudomonas/metabolismo , Animais , Clorofenóis , Besouros/metabolismo , Água Subterrânea , Inativação Metabólica , Cinética , Nitratos , Oxigênio/metabolismo , Praguicidas
4.
Arch Insect Biochem Physiol ; 103(1): e21642, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31667890

RESUMO

The Colorado potato beetle (Leptinotarsa decemlineata [Say]) is an insect pest that can significantly harm potato plants worldwide. Control of this insect relies heavily on chemical insecticides such as chlorantraniliprole. Nevertheless, the complete molecular signature associated with response to this compound is lacking in L. decemlineata. In this study, amplification and quantification by qRT-PCR (quantitative reverse transcription-polymerase chain reaction) of targets relevant to chlorantraniliprole were undertaken in insects exposed to this chemical. This approach showed modulation of numerous cytochrome P450s, such as CYP350D1 and CYP4Q3, as well as upregulation of microRNAs (miRNAs), including miR-1-3p and miR-305-5p, in chlorantraniliprole-exposed insects. Functional assessment of transcript targets predicted to be regulated by these miRNAs was performed and revealed their likely impact on transcriptional regulation. RNAi-based targeting of CYP350D1 notably provided preliminary evidence of its underlying implication for chlorantraniliprole response in L. decemlineata. Overall, this study strengthens the current knowledge of the molecular changes linked to chlorantraniliprole response in L. decemlineata and provides novel targets with potential relevance to chlorantraniliprole susceptibility in this insect pest of global relevance.


Assuntos
Besouros/efeitos dos fármacos , Besouros/metabolismo , Inseticidas/farmacologia , ortoaminobenzoatos/farmacologia , Animais , Sistema Enzimático do Citocromo P-450/genética , Sistema Enzimático do Citocromo P-450/metabolismo , Regulação da Expressão Gênica , MicroRNAs/genética , MicroRNAs/metabolismo , Interferência de RNA , Reação em Cadeia da Polimerase Via Transcriptase Reversa
5.
J Insect Sci ; 19(6)2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31765476

RESUMO

The ectoparasitic fungus Hesperomyces virescens was studied on its invasive host, the harlequin ladybird Harmonia axyridis, in the Czech Republic. A primary aim was to examine the relationship between fungal infection and elytral coloration of the ladybird. Furthermore, the role of host sex and mating status of females were analyzed. Beetles (n = 1,102) were sampled during autumn migration, and then sexed, weighed, and screened for infection. Females were dissected for detection of sperm in their spermathecae. Ladybirds were sorted according to color form and absorbance spectrophotometry was used to quantify carotenoid contents in their elytra. In individuals of the nonmelanic succinea form, the degree of melanization was measured using digital photographs and putative age groups were estimated based on background color of elytra. Sexual differences in infection patterns indicated transmission during copulation: males were infected mostly on elytra and venter, and females had infection almost exclusively on elytra. Mated females had higher infection rate than virgins. There was no influence of genetic color form on the fungal infection. Putative age groups (visual sorting to yellow, orange, and red) correlated with fungal infection. Infected individuals had elevated elytral carotenoid levels in comparison to uninfected individuals, which could be explained by host age. Infection-free succinea beetles were extensively melanized because they emerged later in the season at lower temperatures which induced melanization. Overall, we highlight that H. axyridis is a multivoltine species whose age, if not taken into account in ecophysiological studies, might present a considerable confounding factor.


Assuntos
Ascomicetos/fisiologia , Besouros/microbiologia , Interações Hospedeiro-Patógeno , Pigmentação , Comportamento Sexual Animal , Animais , Carotenoides/metabolismo , Besouros/metabolismo , Feminino , Masculino , Melaninas/metabolismo , Modelos Biológicos
6.
J Insect Sci ; 19(6)2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31752020

RESUMO

Galeruca daurica (Joannis) has become a new insect pest in the Inner Mongolia grasslands since 2009, and its larvae and eggs have strong cold tolerance. To get a deeper insight into its molecular mechanisms of cold stress responses, we performed de novo transcriptome assembly for G. daurica by RNA-Seq and compared the transcriptomes of its larvae exposed to five different temperature treatments (-10, -5, 0, 5, and 25°C for 1 h and then recovered at 25°C for 1 h), respectively. Compared with the control (25°C), the numbers of differentially expressed genes (DEGs) decreased from 1,821 to 882, with the temperature declining from 5 to -10°C. Moreover, we obtained 323 coregulated DEGs under different low temperatures. Under four low temperatures (-10, -5, 0, and 5°C), a large number of genes were commonly upregulated during recovery from cold stresses, including those related to cuticle protein, followed by cytochrome P450, clock protein, fatty acid synthase, and fatty acyl-CoA reductase; meanwhile, lots of genes encoding cuticle protein, RNA replication protein, RNA-directed DNA polymerase, and glucose dehydrogenase were commonly downregulated. Our findings provide important clues for further investigations of key genes and molecular mechanisms involved in the adaptation of G. daurica to harsh environments.


Assuntos
Resposta ao Choque Frio , Besouros/metabolismo , Transcriptoma , Animais , Besouros/genética , Regulação da Expressão Gênica
7.
PLoS Biol ; 17(11): e3000541, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31774806

RESUMO

Evolutionarily conserved insulin/insulin-like growth factor (IGF) signaling (IIS) has been identified as a major physiological mechanism underlying the nutrient-dependent regulation of sexually selected weapon growth in animals. However, the molecular mechanisms that couple nutritional state with weapon growth remain largely unknown. Here, we show that one specific subtype of insulin-like peptide (ILP) responds to nutrient status and thereby regulates weapon size in the broad-horned flour beetle Gnatocerus cornutus. By using transcriptome information, we identified five G. cornutus ILP (GcorILP1-5) and two G. cornutus insulin-like receptor (GcorInR1, -2) genes in the G. cornutus genome. RNA interference (RNAi)-mediated gene silencing revealed that a certain subtype of ILP, GcorILP2, specifically regulated weapon size. Importantly, GcorILP2 was highly and specifically expressed in the fat body in a condition-dependent manner. We further found that GcorInR1 and GcorInR2 are functionally redundant but that the latter is partially specialized for regulating weapon growth. These results strongly suggest that GcorILP2 is an important component of the developmental mechanism that couples nutritional state to weapon growth in G. cornutus. We propose that the duplication and subsequent diversification of IIS genes played a pivotal role in the evolution of the complex growth regulation of secondary sexual traits.


Assuntos
Besouros/crescimento & desenvolvimento , Besouros/metabolismo , Somatomedinas/metabolismo , Animais , Besouros/genética , Insulina/metabolismo , Larva/metabolismo , Peptídeos , Interferência de RNA , Receptor de Insulina/genética , Receptores de Somatomedina/genética , Receptores de Somatomedina/metabolismo , Caracteres Sexuais , Transdução de Sinais , Somatomedinas/fisiologia , Sequenciamento Completo do Exoma
8.
Photochem Photobiol Sci ; 18(11): 2682-2687, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31528963

RESUMO

Bioluminescence spectra of firefly luciferases are affected by pH, heavy metals and high temperatures. Previously, we compared the effect of pH and heavy metals on the bioluminescence spectra of different firefly luciferases and showed that such spectral sensitivity can be harnessed to ratiometrically estimate the pH inside cells and metal concentration. Here, we compared the effect of temperature on the spectral sensitivity of four firefly luciferases (Amydetes vivianii: 539 nm; Cratomorphus distinctus: 548 nm; Photinus pyralis: 558 nm and Macrolampis sp2: 594 nm) and investigated whether a ratiometric curve could be used to estimate temperature. The ratio of intensities of bioluminescence at two wavelengths (green and red) at different temperatures (5-35 °C) was determined. The results confirm that, in the case of pH-sensitive luciferases, the more blue-shifted the bioluminescence spectrum, the more thermostable the enzyme and the less sensitive the emission spectrum to temperature. An almost linear relationship between temperature and the ratio of bioluminescence intensities in the green and red region of the spectrum was found for the four luciferases: the more blue-shifted and less sensitive luciferases exhibit a smaller slope and the more red-shifted luciferases exhibit a steeper slope in the following order: Amy < Crt < Ppy < Mac. This relationship offers the possibility of using firefly luciferases as ratiometric indicators of temperature and may allow the compensation of the effect of temperature in the ratiometric analysis of intracellular pH and heavy metal concentration for each enzyme.


Assuntos
Luciferases de Vaga-Lume/química , Medições Luminescentes/métodos , Animais , Técnicas Biossensoriais/métodos , Besouros/metabolismo , Concentração de Íons de Hidrogênio , Luciferases de Vaga-Lume/genética , Luciferases de Vaga-Lume/metabolismo , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Proteínas Recombinantes/isolamento & purificação , Temperatura Ambiente
9.
Insect Biochem Mol Biol ; 114: 103227, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31470084

RESUMO

Insects employ neuropeptides to regulate their growth & development, behaviour, metabolism and their internal milieu. At least 50 neuropeptides are known to date, with some ancestral to the insects and others more specific to particular taxa. In order to understand the evolution and essentiality of neuropeptides, we data mined publicly available high quality genomic or transcriptomic data for 31 species of the largest insect Order, the Coleoptera, chosen to represent the superfamilies' of the Adephaga and Polyphaga. The resulting neuropeptide distributions were compared against the habitats, lifestyle and other parameters. Around half of the neuropeptide families were represented across the Coleoptera, suggesting essentiality or at least continuing utility. However, the remaining families showed patterns of loss that did not correlate with any obvious life history parameter, suggesting that these neuropeptides are no longer required for the Coleopteran lifestyle. This may perhaps indicate a decreasing reliance on neuropeptide signaling in insects.


Assuntos
Evolução Biológica , Besouros/metabolismo , Neuropeptídeos/metabolismo , Sequência de Aminoácidos , Animais , Comportamento Alimentar , Genoma de Inseto , Muda , Reprodução , Transcriptoma , Equilíbrio Hidroeletrolítico
10.
Int J Biol Macromol ; 136: 359-367, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31173835

RESUMO

Holotrichia oblita is one of the nastiest pests in China. In present research, four full-length cDNA encoding of HoblOBP genes were cloned and sequenced from H. oblita. The mRNA of HoblOBPs were predominantly expressed in antenna. The recombinant HoblOBPs proteins were obtained for fluorescence binding assays. Four of HoblOBPs could mediate the response of H. oblita to organic fertilizers-derived attractants, including HoblOBP5 binding to skatole; HoblOBP8 binding to p-cresol, indole and skatole; HoblOBP9 binding to indole and 4-allylanisole; and HoblOBP24 binding to p-cresol, indole and 4-ethylphenol. Further, RNA interference demonstrated that transcripts of HoblOBP5, 8, 9, and 24 decreased in a time-dependent manner after dsRNA-injection. Knockdown of HoblOBP5, 8, 9, and 24 by injection of dsRNA successfully interfered with behavioral responses towards the target compounds in beetles. Our results showed that HoblOBP5, HoblOBP8, HoblOBP9 and HoblOBP24 are essential in mediating the approach behavior of H. oblita.


Assuntos
Besouros/genética , Besouros/metabolismo , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Receptores Odorantes/genética , Receptores Odorantes/metabolismo , Sequência de Aminoácidos , Animais , Comportamento Animal , Besouros/fisiologia , Regulação da Expressão Gênica , Proteínas de Insetos/química , Proteínas de Insetos/deficiência , Oviposição , Interferência de RNA , RNA Mensageiro/genética , Receptores Odorantes/química , Receptores Odorantes/deficiência
11.
J Insect Physiol ; 117: 103899, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31202853

RESUMO

Salinity tolerance has enabled the colonization of inland saline waters and promoted species diversification in some lineages of aquatic insects. However, the mechanisms behind this tolerance, particularly the role of cuticle hydrocarbons (CHCs), are not well-known. We characterized the CHC profile of eight species of two water beetle genera (Nebrioporus, Adephaga: Dytiscidae and Enochrus, Polyphaga: Hydrophilidae), which span the fresh-hypersaline gradient, to: i) determine the interspecific variation of CHC composition in relation to species' salinity tolerance; ii) explore plastic adjustments in CHC profiles in response to salinity changes at the intraspecific level in saline-tolerant species. CHC profiles were highly species-specific, more complex and diverse in composition, and characterized by longer-chain-length compounds in the species with higher salinity tolerance within each genus. Higher salinity tolerance in the Enochrus species was also associated with an increase in the relative abundance of branched alkanes, and with a lower proportion of n-alkanes and unsaturated compounds. These CHC characteristics are related with improved waterproofing capacity and suggest that reducing cuticle permeability was one of the key mechanisms to adapt to saline waters. Similar CHC composition patterns were found at the intraspecific level between populations from lower and higher salinity sites within saline-tolerant species of each genus. These saline species also displayed an extraordinary ability to adjust CHC profiles to changing salinity conditions in the laboratory in a relatively short time, which reflects great plasticity and a high potential to deal with daily and seasonal environmental fluctuations in the highly dynamic saline habitats.


Assuntos
Besouros/metabolismo , Hidrocarbonetos/metabolismo , Tolerância ao Sal , Água/fisiologia , Aclimatação , Animais , Pressão Osmótica , Especificidade da Espécie
12.
Environ Monit Assess ; 191(6): 372, 2019 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-31101990

RESUMO

The expression levels of Esterase Isoenzyme and total soluble protein fractionation were studied in two coleopteran insects Blaps polycresta and Trachyderma hispida to evaluate the possible hazards from ceramic and plastic factories in the Khorshed Region, East of Alexandria, Egypt. Two insect collection sites were selected. The first site was the garden of the Faculty of Science, Moharram Bek, Alexandria University, which is considered a non-polluted site, and Khorshed district, considered as the polluted site. Percentages of heavy metals were estimated using SEM-X-ray microanalysis of soft tissues of both sexes of the two coleopteran insects. Esterase Isoenzymes were found to be overexpressed in B. Polycresta but not T. hispida. Female B. polycresta from the polluted site exhibited overexpression of the second and third loci. Furthermore, the females were found to be more affected than males, which only showed the overexpression of the second loci. T. hispida (females and males) collected from the reference site were found to have increased esterase activity compared with those sampled from the polluted site. The Snake-Skin™ Dialysis tubing technique, used for optimizing the protein extraction method, reflected the highest quantified proteins compared to other, traditional methods. SDS polyacrylamide gel electrophoresis (SDS-PAGE) analysis of the whole-body protein reflected definite variations between T. hispida and B. polycresta in fraction number and activity at the two sites. Varied expression levels for metallothionein (MT) heavy metal resistance proteins for B. polycresta and T. hispida were also detected in the study. Based on these results, we suggest that biochemical biomarkers could infer environmental hazards, B. polycresta and T. hispida are successful biomarkers for heavy metal pollution.


Assuntos
Cerâmica , Besouros/efeitos dos fármacos , Monitoramento Ambiental/métodos , Poluição Ambiental/análise , Proteínas de Insetos/metabolismo , Isoenzimas/metabolismo , Animais , Biomarcadores/metabolismo , Besouros/genética , Besouros/metabolismo , Egito , Poluição Ambiental/efeitos adversos , Feminino , Expressão Gênica/efeitos dos fármacos , Indústrias , Proteínas de Insetos/genética , Isoenzimas/genética , Masculino , Metalotioneína/genética , Metalotioneína/metabolismo , Metais Pesados/análise , Metais Pesados/toxicidade , Fatores Sexuais , Especificidade da Espécie
13.
PLoS One ; 14(5): e0216753, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31071168

RESUMO

The mountain pine beetle (MPB; Dendroctonus ponderosae) is a forest insect pest that attacks several different pine (Pinus) species in its native range of distribution in western North America. MPB are exposed for most of their life cycle to the chemical defenses of their hosts. These defenses are dominated by oleoresin secretions containing mostly various monoterpenes and diterpene resin acids (DRAs). Cytochrome P450 enzymes (P450s) of the MPB are thought to be involved in the metabolism of at least some of these defense compounds. Here we describe the cloning and characterization of three MPB P450s, CYP6DJ1, CYP6BW1 and CYP6BW3, and their functions in the oxidation of various monoterpenes and diterpene resin acids. CYP6DJ1 oxidizes the monoterpenes (+)-(4R)-limonene, (-)-(4S)-limonene and terpinolene and produces (4R,8R)-limonene-8,9-epoxide, (4R,8S)-limonene-8,9-epoxide, (4S,8S)-limonene-8,9-epoxide, (4S,8R)-limonene-8,9-epoxide, perilla alcohol and several unidentified oxidized compounds. These products of CYP6DJ1 were also identified in extracts of MPB treated with the same monoterpenes. CYP6BW1 and CYP6BW3 both oxidize the DRAs abietic acid, dehydroabietic acid, neoabietic acid, levopimaric acid, palustric acid, and isopimaric acid, producing hydroxylated and epoxidized DRAs. CYP6DJ1, CYP6BW1 and CYP6BW3 appear to contribute to the metabolism of oleoresin terpenes as part of the MPB's ability to cope with host defenses.


Assuntos
Besouros/metabolismo , Besouros/patogenicidade , Família 6 do Citocromo P450/metabolismo , Proteínas de Insetos/metabolismo , Pinus/parasitologia , Animais , Besouros/genética , Família 6 do Citocromo P450/genética , Diterpenos/metabolismo , Florestas , Proteínas de Insetos/genética , Limoneno/metabolismo , Monoterpenos/metabolismo , Oxirredução , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Resinas Vegetais/metabolismo , Especificidade por Substrato
14.
Bull Entomol Res ; 109(5): 695-700, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30971323

RESUMO

Colorado potato beetle (Leptinotarsa decemlineata, Say) is the main pest of Solanaceae and its survival is mainly dependent on the carbohydrate digestion. Characterizing the gut enzymes may help us with finding effective inhibitors for plant protection. Activity measurements revealed that gut extracts contain α- and ß-glucosidase in addition to α-amylase. For larvae, amylase activity was detected only in gut saturated with nutrients. Leptinotarsa decemlineata α-amylase (LDAmy) had optimum pH of 6.0 and was active under 30-40°C temperature measured on a selective α-amylase substrate, 2-chloro-4-nitrophenyl-4-O-α-D-galactopyranosyl-maltoside. HPLC analysis demonstrated dimer, trimer, and tetramer reducing end amylolytic products from 2-chloro-4-nitrophenyl-maltoheptaoside substrate in similar ratio than that of during porcine pancreatic α-amylase (PPA) catalyzed hydrolysis. The 4,6-O-benzylidene-modified substrate (BzG7PNP) is very stable toward hydrolysis by exo-glycosidases, therefore is very useful to monitor the digestion catalyzed by α-amylases exclusively. Similarly to PPA active site, three glycon and two aglycon binding sites are suggested for LDAmy based on the pattern of early hydrolysis products of BzG7PNP. The observed similarity between LDAmy and PPA raises the possibility of using known inhibitors of mammalian α-amylases to protect the potato plant from attack of Colorado potato beetle.


Assuntos
Metabolismo dos Carboidratos , Besouros/enzimologia , Sistema Digestório/enzimologia , Animais , Besouros/metabolismo , Concentração de Íons de Hidrogênio , Larva/enzimologia , Larva/metabolismo , Temperatura Ambiente , alfa-Amilases , alfa-Glucosidases , beta-Glucosidase
15.
J Insect Physiol ; 115: 27-32, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30935980

RESUMO

The insect peritrophic membrane (PM) is a non-cellular structure composed of secreted proteins imbedded in a proteoglycan matrix together with chitin. It separates the midgut epithelium from the intestinal contents, and functions in the digestion of food. Furthermore it acts as a protective barrier against abrasive particles and microbial infections. Here we studied for the first time the N-glycome of the PM. We identified the N-glycan structures present in the PM of the Colorado potato beetle (CPB) at the fourth larval stage using MALDI-TOF mass spectrometry. In parallel, we correlated the N-glycan data to the presence of the N-glycosylation related genes (NGRGs) in the transcriptome of epithelial midgut cells. The presumed activities of the identified genes support the N-glycan profile resolved for the proteins in the PM. To our knowledge these data are the first report on the N-glycome of the PM of a pest insect. These results will contribute to the study of the importance of N-glycosylation in the function and structure of the PM. In addition, the data can help to find novel targets and design better biopesticides for pest control.


Assuntos
Besouros/metabolismo , Polissacarídeos/metabolismo , Animais , Trato Gastrointestinal/metabolismo , Glicosilação , Larva/metabolismo , Transcriptoma
16.
Cryobiology ; 88: 54-63, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30946844

RESUMO

The Colorado potato beetle (Leptinotarsa decemlineata (Say)) is an insect that can cope with prolonged periods of low temperatures exposure. The molecular changes required to adapt to such conditions have not been thoroughly investigated in this insect. The current work aims at characterizing deregulated transcripts and proteins in adult L. decemlineata exposed to 15 °C and -5 °C using RNA-sequencing-based transcriptomics and liquid chromatography tandem mass spectrometry (LC-MS/MS)-based proteomics approaches, respectively. RNA-sequencing highlighted the differential expression of several transcripts, including ubiquilin-1 and ubiquitin carboxyl-terminal hydrolase 5, in insects submitted to low temperatures when compared with control insects. In addition, proteomics approach detected 2840 proteins in cold-exposed beetles including elevated levels for 409 proteins and reduced levels for 200 proteins. Cuticular proteins CP1, CP4, CP5 and CP7 as well as eukaryotic translation initiation factor 4B were notable proteins with elevated levels in cold insects. Functional analysis of targets modulated at low temperatures using DAVID indicated processes likely affected under cold conditions including select metabolic cascades and RNA-associated processes. Overall, this work presents molecular candidates impacted by low temperatures exposure in L. decemlineata and builds on the current knowledge associated with response to these conditions in this insect.


Assuntos
Resposta ao Choque Frio/fisiologia , Besouros/metabolismo , Proteoma/metabolismo , Animais , Cromatografia Líquida , Temperatura Baixa , Criopreservação , Espectrometria de Massas em Tandem , Transcriptoma
17.
J Chem Ecol ; 45(4): 366-370, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30931507

RESUMO

Insect pheromones have rarely been exploited in surveys or studies of rare and endangered species, despite their potential as effective and highly selective attractants for target species. Here, we report the identification, synthesis, and field bioassays of a male-produced aggregation-sex pheromone blend of a rare false click beetle species endemic to southern California, Dohrn's elegant eucnemid beetle, Palaeoxenus dohrni Horn (Coleoptera: Eucnemidae). This species is the only extant species in its genus and subfamily. Analyses of extracts of headspace volatiles collected from adult beetles revealed several male-specific compounds. Two of these compounds, identified as (E)-2-nonen-4-one and (R)-2-nonanol, elicited electroantennographic responses from antennae of beetles of both sexes. In field bioassays, a blend of the two compounds attracted both sexes, whereas the individual compounds were not attractive. The identification of an attractant pheromone should provide a useful tool for bioconservation and ecological studies of this iconic species.


Assuntos
Alcenos/metabolismo , Besouros/metabolismo , Álcoois Graxos/metabolismo , Atrativos Sexuais/metabolismo , Animais , Antenas de Artrópodes/fisiologia , Bioensaio , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Masculino , Compostos Orgânicos Voláteis/metabolismo
18.
Ecotoxicology ; 28(4): 422-428, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30868349

RESUMO

Contamination of environment with heavy metals is increasingly becoming an issue of major concern across the globe. Heavy metals are highly toxic to humans as well as other organisms of the ecosystem. The translocation of heavy metals from soil to predatory insects via multi-tophic food chains can influence the growth, reproduction, metabolism and innate immune systems of the predators. This study was performed to observe the changes in energy metabolism and immune responses of Cryptolaemus montrouzieri feeding on heavy metal (Cd, Pb, Ni and Zn) contaminated pink hibiscus mealybug (Dysmicoccus neobrevipes). The average concentrations of Cd, Pb, Ni and Zn in mealybugs used for feeding assays were 30.57, 32.64, 31.47 and 33.19 mg/kg, respectively. The results showed a significant increase in total protein, glycogen, cholesterol and triglycerides content of C. montrouzieri feeding on heavy metals contaminated mealybugs compared with control groups. The activities of endogenous enzymes (acid phosphatase and alkaline phosphatase) as well as antioxidant enzymes (SOD, POD and CAT) were significantly higher in beetles feeding on heavy metals contaminated mealybugs. Our results provide basic insight into the influences of heavy metals (Cd, Pb and Ni) on energy metabolism and the innate immune system of the insect predator (C. montrouzieri) in a multi-trophic food chain. Further research on genetic processes involved in the regulation of metabolism and innate immune system of C. montrouzieri is still needed.


Assuntos
Besouros/efeitos dos fármacos , Metabolismo Energético/efeitos dos fármacos , Poluentes Ambientais/metabolismo , Imunidade Inata/efeitos dos fármacos , Metais Pesados/metabolismo , Animais , Besouros/metabolismo , Cadeia Alimentar
19.
Insect Biochem Mol Biol ; 109: 81-91, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30922827

RESUMO

Sequestration of plant secondary metabolites is a detoxification strategy widespread in herbivorous insects including not only storage, but also usage of these metabolites for the insects' own benefit. Larvae of the poplar leaf beetle Chrysomela populi sequester plant-derived salicin to produce the deterrent salicylaldehyde in specialized exocrine glands. To identify putative transporters involved in the sequestration process we investigated integral membrane proteins of several tissues from juvenile C. populi by using a proteomics approach. Computational analyses led to the identification of 122 transport proteins in the gut, 105 in the Malpighian tubules, 94 in the fat body and 27 in the defensive glands. Among these, primary active transporters as well as electrochemical potential-driven transporters were most abundant in all tissues, including ABC transporters (especially subfamilies B, C and G) and sugar porters as most interesting families facilitating the sequestration of plant glycosides. Whereas ABC transporters are predominantly expressed simultaneously in several tissues, sugar porters are often expressed in only one tissue, suggesting that sugar porters govern more distinct functions than members of the ABC family. The inventory of transporters presented in this study provides the base for further functional characterizations on transport processes of sequestered glycosides in insects.


Assuntos
Álcoois Benzílicos/metabolismo , Besouros/genética , Glucosídeos/metabolismo , Proteínas de Insetos/genética , Proteínas de Membrana/genética , Transcriptoma/genética , Animais , Besouros/crescimento & desenvolvimento , Besouros/metabolismo , Perfilação da Expressão Gênica , Herbivoria , Proteínas de Insetos/metabolismo , Larva/genética , Larva/crescimento & desenvolvimento , Larva/metabolismo , Proteínas de Membrana/metabolismo
20.
Cell Stress Chaperones ; 24(3): 539-547, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30815817

RESUMO

The Colorado potato beetle (Leptinotarsa decemlineata (Say)) is an agricultural pest that threatens the potato industry worldwide. This insect is widely regarded as one of the most difficult-to-control pests, as it can thrive in a wide range of temperature conditions and routinely develops resistance towards various insecticides. The molecular changes associated with response to these challenges have not been fully investigated in L. decemlineata. While differential expression and characterization of heat shock proteins (HSPs) in response to stress have been conducted in several insects, data regarding HSPs in L. decemlineata are limited. The overarching objective of this study consisted of evaluating the expression of various HSPs in L. decemlineata exposed to different temperatures or treated with the insecticides imidacloprid and chlorantraniliprole. Expression levels of HSP60, HSP70, HSP90, and HSP Beta-1 were evaluated by qRT-PCR and insect mortality was assessed using dsRNAs aimed at select HSP targets. Elevated HSP70 and HSP90 transcript levels were observed in heat-exposed L. decemlineata while downregulation of HSP70 transcript levels was measured in insects submitted to cold conditions. Chlorantraniliprole exposure was associated with reduced HSP Beta-1 transcript levels while no change in expression was monitored in insects exposed to imidacloprid. RNAi-based knockdown of HSP60 levels correlated with significant insect mortality 14 days after dsRNA injection. These results highlight the modulation of HSPs that occur in L. decemlineata exposed to fluctuating temperatures and position HSPs as interesting candidates in the identification of novel molecular leads that could be targeted to control this insect.


Assuntos
Besouros/metabolismo , Proteínas de Choque Térmico/metabolismo , Estresse Fisiológico , Animais , Temperatura Baixa , Temperatura Alta , Neonicotinoides/metabolismo , Nitrocompostos/metabolismo , ortoaminobenzoatos/metabolismo
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