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1.
An Acad Bras Cienc ; 91(3): e20181008, 2019 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-31432904

RESUMO

Leaf-cutting ants are considered major pests of agriculture and forestry in the Neotropics. Attractive toxic baits are the prevailing method for managing them. Thus, there is great interest in identifying attractants to incorporate into these baits. Moreover, leaf-cutting ants can avoid toxic baits by associating the attractant with the toxin. We evaluated attractiveness of heptyl butyrate, a volatile compound found in fresh apples and plums. We conducted field experiments with ten colonies of Acromyrmex lobicornis. First, we evaluated the behaviour of ants exposed to heptyl butyrate at 1% by surrounding resources. Then, we compared the attractiveness of heptyl butyrate and orange pulp, the most commonly used attractant. Finally, we evaluated whether heptyl butyrate increases the attractiveness of a carbohydrate resource at varying doses. Heptyl butyrate at 1% attracted 92% more ants than the control and that it was as attractive as orange pulp. Heptyl butyrate paired with sucrose at concentrations of 0.001 and 0.1% was more attractive than sucrose alone, but greater concentrations did not increase sucrose's attractiveness. Therefore, heptyl butyrate could be added to toxic baits to manage A. lobicornis as it is as attractive as the most commonly used attractant and can be applied directly to the pellets.


Assuntos
Formigas/efeitos dos fármacos , Controle de Insetos/métodos , Feromônios/química , Animais , Bioensaio , Feromônios/isolamento & purificação , Feromônios/farmacologia
2.
J Chem Ecol ; 45(8): 649-656, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31407197

RESUMO

Pheromone-baited traps can be excellent tools for sensitive detection of insects of conservation concern. Here, identification of the sex pheromone of Trichopteryx polycommata (Denis & Schiffermüller, 1775), an under-recorded UK priority species, is reported. In analyses of extracts of the pheromone glands of female T. polycommata by gas chromatography coupled to electroantennographic recording from the antenna of a male moth, a single active component was detected. This was identified as (Z,Z)-6,9-nonadecadiene (Z,Z6,9-19:H) by comparison of its mass spectrum and retention times with those of the synthetic standard. In a pilot field trial in Kent, UK, T. polycommata males were caught in pheromone traps baited with lures loaded with 1 mg and 2 mg (Z,Z)-6,9-19:H. Optimum lure loading was identified in a further five trials in Kent, Sussex and Lancashire where lures of 0, 0.001, 0.01, 0.1, 1, 2, 5 and 10 mg loadings were tested. Traps baited with 1 to 10 mg of ZZ6,9-19:H caught significantly more T. polycommata than traps baited with 0 mg and 0.001 mg. In a pilot survey of T. polycommata using pheromone lures around Morecambe Bay, UK, T. polycommata males were captured at 122 new sites within the three counties where trials took place, demonstrating the potential of pheromone monitoring to increase knowledge of abundance, distribution and ecology of this elusive species.


Assuntos
Mariposas/fisiologia , Atrativos Sexuais/química , Animais , Espécies em Perigo de Extinção , Ácidos Graxos Insaturados/química , Ácidos Graxos Insaturados/farmacologia , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Masculino , Feromônios/química , Feromônios/farmacologia , Atrativos Sexuais/farmacologia , Comportamento Sexual Animal/efeitos dos fármacos
3.
J Chem Ecol ; 45(8): 657-666, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31407199

RESUMO

The box tree moth, Cydalima perspectalis, is an invasive pest in Europe causing damage on Buxus species. In this study, we aimed to develop a "bisexual" lure to attract both female and male moths. Based on a previous screening bioassay we tested methyl salicylate, phenylacetaldehyde and eugenol as potential attractants in different combinations. The trapping results showed that both binary and ternary blends attracted male and female moths. Catches with these blends were comparable to catches with the synthetic pheromone. Subsequently we carried out single sensillum recordings, which proved the peripheral detection of the above-mentioned compounds on male and female antennae. To identify synergistic flower volatiles, which can be also attractive and can increase the trap capture, we collected flower headspace volatiles from 12 different flowering plant species. Several components of the floral scents evoked good responses from antennae of both females and males in gas chromatography-electroantennographic detection. The most active components were tentatively identified by gas chromatography coupled mass spectrometry as benzaldehyde, cis-ß-ocimene, (±)-linalool and phenethyl alcohol. These selected compounds in combination did not increase significantly the trap capture compared to the methyl salicylate- phenyacetaldehyde blend. Based on these results we discovered the first attractive blend, which was able to attract both adult male and female C. perspectalis in field conditions. These results will yield a good basis for the optimization and development of a practically usable bisexual lure against this invasive pest.


Assuntos
Comportamento Animal/efeitos dos fármacos , Mariposas/fisiologia , Feromônios/farmacologia , Animais , Eugenol/química , Eugenol/farmacologia , Feminino , Flores/química , Flores/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Controle de Insetos , Masculino , Monoterpenos/química , Monoterpenos/farmacologia , Feromônios/análise , Robinia/química , Robinia/metabolismo , Rosa/química , Rosa/metabolismo , Compostos Orgânicos Voláteis/química , Compostos Orgânicos Voláteis/farmacologia
4.
J Chem Ecol ; 45(7): 588-597, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31342233

RESUMO

Honey bee (Apis mellifera) queens produce pheromones responsible for mediating both male mating behavior and many critical facets of worker social organization within their colony. These pheromones are dynamic multi-component blends, allowing the communication of detailed information. Indeed, variation in the queen's mating and reproductive state is associated with significant changes in her pheromone profiles, and these different pheromone profiles elicit different behavioral and physiological responses in female workers. Here we evaluate behavioral responses of male drones to the chemical blends produced by two exocrine glands in queens, and determine if the blends and responses are altered by the queen's mating and reproductive state. We find that drone attraction to the chemical blends of mandibular glands produced by mated, laying queens versus virgin queens is reduced, suggesting that the queens produce a reliable signal of their mating receptivity. Interestingly, while the chemical blends of mating, laying queens and virgins queens largely overlap, mated, laying queens produce a greater number of chemicals and greater quantities of certain chemicals than virgin queens, suggesting that these chemicals may serve to inhibit behavioral responses of drones to mated, laying queens. Thus, our results highlight the importance of considering chemical cues and signals that serve to both stimulate and inhibit behavioral responses during social interactions in animals.


Assuntos
Comportamento Animal/efeitos dos fármacos , Feromônios/farmacologia , Comunicação Animal , Animais , Abelhas , Glândulas Exócrinas/química , Glândulas Exócrinas/metabolismo , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Masculino , Feromônios/análise , Reprodução/fisiologia
5.
J Chem Ecol ; 45(8): 667-672, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31313134

RESUMO

Agriotes ustulatus is an economically important click beetle in Europe. A female-produced pheromone, (E,E)-farnesyl acetate, has been identified and is used for monitoring and detecting males. More recently, a floral lure targeting females with modest, but significant, activity has been described. Based on preliminary data, we hypothesized, that similar to the effects on the congeneric A. brevis, addition of the pheromone to the floral lure should improve female A. ustulatus catches. Also, as click beetles have been reported to respond to white light, we studied possible interactions between visual and chemical cues. In field trials, the addition of the synthetic pheromone to the floral lure resulted in a dramatic increase in the number of females trapped, whereas male catches remained unaffected and equal to those in traps baited with pheromone only. A white visual cue did not influence trap catches. Maximum catches of both sexes of A. ustulatus can be achieved using the pheromone and the floral lure inside the same trap. Furthermore, the compounds can be formulated in a single polyethylene bag dispenser, making handling of the trap easier. Due to a much larger proportion of females in the catch, this improved trap may be a promising tool for semiochemical-based, environmentally sound agricultural practice against this important pest.


Assuntos
Besouros/fisiologia , Feromônios/química , Acroleína/análogos & derivados , Acroleína/química , Acroleína/farmacologia , Animais , Anisóis/química , Anisóis/farmacologia , Comportamento Animal/efeitos dos fármacos , Farneseno Álcool/análogos & derivados , Farneseno Álcool/química , Farneseno Álcool/farmacologia , Feminino , Flores/química , Flores/metabolismo , Controle de Insetos , Masculino , Feromônios/farmacologia , Estereoisomerismo
6.
J Sci Food Agric ; 99(13): 5899-5909, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31225657

RESUMO

BACKGROUND: Most allelochemicals are secondary products released from root excretions or plant residues that accumulate in continuous cropping systems and cause severe decline in peanut yield. Resveratrol is a plant-derived stilbene that is released from peanut residues and accumulates in the soil; however, its allelopathic effects on peanut production are overlooked. Effective management solutions need to be developed to relieve allelopathy caused by soil resveratrol. Here, the biodegradation of resveratrol by the fungal endophyte Phomopsis liquidambari was investigated in a mineral salt medium and a soil trial. Resveratrol and its metabolites (produced by degradation by P. liquidambari) were detected by high-performance liquid chromatography-mass spectrometry (HPLC-MS). RESULTS: Resveratrol released from peanut residues reached a maximum concentration of 0.18 µg g-1 soil in litterbag experiments. Exogenous resveratrol inhibited peanut growth, nodule formation, and soil dehydrogenase activity, and reduced the soil microbial biomass carbon content and bacterial abundance, indicating an allelopathic role in peanut growth. More than 97% of the resveratrol was degraded within 72 and 168 h by P. liquidambari in pure culture and soil conditions, respectively. Resveratrol was first cleaved to 3,5-dihydroxybenzaldehyde and 4-hydroxybenzaldehyde, which were subsequently oxidized into 3,5-dihydroxybenzoic acid and 4-hydroxybenzoic acid, respectively. Fungal resveratrol cleavage oxygenase and the related gene expression were enhanced when P. liquidambari was induced by the resveratrol during the incubation. CONCLUSION: Our results indicate that the practical application of the fungal endophyte P. liquidambari has strong potential for biodegrading soil resveratrol, which can cause allelopathy in peanut continuous cropping systems. © 2019 Society of Chemical Industry.


Assuntos
Arachis/química , Ascomicetos/metabolismo , Endófitos/metabolismo , Feromônios/metabolismo , Resveratrol/metabolismo , Arachis/metabolismo , Arachis/microbiologia , Bactérias/classificação , Bactérias/efeitos dos fármacos , Bactérias/genética , Bactérias/isolamento & purificação , Biodegradação Ambiental , Feromônios/análise , Feromônios/farmacologia , Resveratrol/análise , Resveratrol/farmacologia , Solo/química , Microbiologia do Solo
7.
J Chem Ecol ; 45(7): 570-578, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31209625

RESUMO

The brown spiny bug, Clavigralla tomentosicollis Stål (Hemiptera: Coreidae) is a key pest of leguminous crops in many countries in Africa, causing significant yield losses especially in cowpea, pigeon pea and common beans. Although C. tomentosicollis uses olfaction to aggregate, little is known about the identity of the aggregation pheromone. This study aimed to identify the aggregation pheromone of C. tomentosicollis and to test its potential role in the behavior of its egg parasitoid, Gryon sp. In Y-tube olfactometer bioassays, only male volatiles strongly attracted both sexes of C. tomentosicollis. Coupled gas chromatography/electroantennographic detection (GC/EAD) and GC/mass spectrometry were used to identify antennally-active compounds from male volatiles. Antennae of both sexes detected identical components including a male-specific component, identified as isopentyl butanoate, which was also detected by antenna of the egg parasitoid. In olfactometer bioassays, both sexes of C. tomentosicollis and the egg parasitoid responded to isopentyl butanoate. These results suggest that isopentyl butanoate serves as an aggregation pheromone for both sexes of C. tomentosicollis and a useful kairomone to attract the parasitoid in the management of C. tomentosicollis.


Assuntos
Butiratos/química , Hemípteros/fisiologia , Himenópteros/crescimento & desenvolvimento , Hormônios de Inseto/química , Feromônios/química , Animais , Comportamento Animal/efeitos dos fármacos , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Masculino , Óvulo/química , Óvulo/metabolismo , Feromônios/isolamento & purificação , Feromônios/farmacologia , Vigna/parasitologia , Compostos Orgânicos Voláteis/química , Compostos Orgânicos Voláteis/isolamento & purificação
8.
Environ Sci Pollut Res Int ; 26(22): 22389-22399, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31154644

RESUMO

This paper studied the inhibitory effect of pomegranate peel (PP) extract on the growth of Microcystis aeruginosa, the model of harmful algal blooms in aquatic environment. The allelochemicals were identified by HPLC-MS/MS from PP and tested by batch experiment through measurement of algal density, chlorophyll a (Chl-a) concentration, maximum quantum yield of photosystem II (Fv/Fm), superoxide dismutase (SOD), and malondialdehyde (MDA) contents. Results showed that both PP powder and PP extract had obvious inhibitory effect on M. aeruginosa growth. Quercetin and luteolin were identified as the allelochemicals to M. aeruginosa growth. However, the inhibitory capacity of luteolin was stronger than that of quercetin. The growth inhibition ratio of luteolin can reach up to 98.7 and 99.1% of the control on day 7 at the dosages of 7 and 10 mg/L, respectively. Moreover, the changes of Chl-a, Fv/Fm, SOD, and MDA in M. aeruginosa confirmed jointly that the allelochemicals cause inhibition of photosystem and oxidative damage to M. aeruginosa cells with the antioxidant defense system being activated, which leads to the aggravation of membrane lipid peroxidation. Thus, luteolin could be used as a promising algaecide for emergency handling of M. aeruginosa blooms. This study might provide a new direction in the management of eutrophication in the future.


Assuntos
Antioxidantes/farmacologia , Clorofila A/química , Proliferação Nociva de Algas/efeitos dos fármacos , Malondialdeído/farmacologia , Microcystis/efeitos dos fármacos , Feromônios/farmacologia , Complexo de Proteína do Fotossistema II/química , Malondialdeído/química , Oxirredução , Complexo de Proteína do Fotossistema II/metabolismo , Punicaceae , Superóxido Dismutase/metabolismo , Espectrometria de Massas em Tandem
9.
Molecules ; 24(9)2019 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-31072064

RESUMO

Safranal, the main volatile chemical of Saffron (Crocus sativus) was studied to estimate its allelopathic effects on the photosynthetic pigment chlorophyll, leaf electrolyte leakage, fresh weight, catalase (CAT), and peroxidase (POX) activity of the test plant Lettuce (Lactuca sativa). In this study, the effective concentration (EC50) of safranal on CAT was estimated to be 6.12 µg/cm3. CAT activity was inhibited in a dose-dependent manner by the increase in the safranal concentration while POX activity was increased. Moreover, Safranal caused significant physiological changes in chlorophyll content, leaf electrolyte leakage, and fresh weight of several weed species with Lolium multiflorum being the most sensitive. Furthermore, 5 µM Safranal showed significant inhibitory activity against dicotyledonous in comparison to the monocotyledons under greenhouse conditions. The inhibition of the CAT by safranal was similar to those of uncompetitive inhibitors, and therefore the decline in carbon fixation by plants might be the mechanism behind the inhibitory activity of safranal.


Assuntos
Crocus/química , Cicloexenos/farmacologia , Alface/fisiologia , Feromônios/farmacologia , Plantas Daninhas/fisiologia , Terpenos/farmacologia , Catalase/metabolismo , Domínio Catalítico , Cicloexenos/química , Glutationa Peroxidase/metabolismo , Alface/efeitos dos fármacos , Pigmentação/efeitos dos fármacos , Plantas Daninhas/efeitos dos fármacos , Plantas Daninhas/crescimento & desenvolvimento , Espécies Reativas de Oxigênio/metabolismo , Terpenos/química , Compostos Orgânicos Voláteis/farmacologia
10.
Microb Pathog ; 131: 197-204, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30980879

RESUMO

The compatibility of the entomopathogenic fungus Metarhizium anisopliae ICIPE 30 which was proved to be pathogenic to adult Spoladea recurvalis, and phenylacetaldehyde (PAA) floral attractant for lepidopteran moths, was investigated under laboratory and field conditions through spatial and temporal separations. Horizontal transmission of M. anisopliae ICIPE 30 between adult S. recurvalis and the number of conidia picked up by a single moth from the autoinoculation device were also determined under laboratory tests. When freshly emerged moths were inoculated with fungal conidia ("donors") and maintained together with an equal number of untreated freshly emerged moths ("recipients") in the laboratory, they were able to transmit infection to untreated moths resulting to 76.9% mortality with an LT50 value of 6.9 days. The quantity of conidia a moth could acquire and retain from the autoinoculation device in the laboratory was assessed at 0, 24, 48, and 72 h post-inoculation. The overall mean number of conidia acquired by a single moth was significantly higher immediately after exposure (0 h) (14.3 ±â€¯2.5 × 105) than at 24, 48, and 72 h after inoculation (F = 10.26, Df = 3,8, P = 0.003), though a single moth still retained 4.6 ±â€¯0.9 × 105 conidia 72 h post inoculation. Laboratory results showed that PAA completely inhibited the germination of the conidia 8 days post exposure, while the conidial viability was not affected in the control treatment without PAA. Under field conditions, the inhibitory effects of PAA on conidial germination was minimized by placing it at a distance of 5-10 cm from M. anisopliae isolate ICIPE 30 conidia. There was no significant difference in conidial germination in the control treatment and in treatments where PAA was placed at 5 cm and 10 cm away from M. anisopliae isolate ICIPE 30. Conidial germination was low in the autoinoculation device that had PAA directly exposed to the fungus. PAA is therefore compatible with M. anisopliae ICIPE 30 for use in integrated management of S. recurvalis, if spatially separated 5 cm away from the fungus and could thus be combined in an autocontamination devices for the control of S. recurvalis.


Assuntos
Acetaldeído/análogos & derivados , Transmissão de Doença Infecciosa/prevenção & controle , Metarhizium/efeitos dos fármacos , Metarhizium/patogenicidade , Mariposas/microbiologia , Micoses/transmissão , Acetaldeído/farmacologia , Animais , Agentes de Controle Biológico , Inseticidas/química , Inseticidas/farmacologia , Larva/crescimento & desenvolvimento , Larva/microbiologia , Micoses/microbiologia , Micoses/prevenção & controle , Controle Biológico de Vetores/métodos , Feromônios/farmacologia , Esporos Fúngicos/efeitos dos fármacos , Esporos Fúngicos/crescimento & desenvolvimento
11.
Ecotoxicol Environ Saf ; 177: 18-24, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-30954008

RESUMO

Flavonoids are natural polyphenolic compounds from plants. As a new biotechnological algaecide, the molecular mechanism of plant flavonoids on the inhibition of Microcystis aeruginosa is still unknown. Therefore, in this study, we analyzed the variation of expressions of photosynthesis-related genes, microcystin synthesis-related genes and the genes involved in N and P acquisition in M. aeruginosa under the flavonoids stress. The results showed that the expression of psbD1, psaB and rbcL related to photosynthesis were influenced by three flavonoids but with different changing tendencies. The transcription of mcyA, mcyD and mcyH related to microcystin synthesis were decreased after 5-d of exposure, which could block microcystin synthesis. Meanwhile, flavonoids treatments resulted in the inhibition of N and P acquisition related genes transcription to affect the absorption of N and P in algal cells, and further influenced the physiological metabolic process of M. aeruginosa.


Assuntos
Flavonoides/farmacologia , Microcistinas/metabolismo , Microcystis/efeitos dos fármacos , Feromônios/farmacologia , Fotossíntese , Metabolismo Secundário , Flavonoides/metabolismo , Variação Genética , Microcistinas/genética , Microcystis/genética , Microcystis/metabolismo , Nutrientes , Feromônios/metabolismo
12.
Chemosphere ; 225: 424-433, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30889406

RESUMO

Microcystis aeruginosa (M. aeruginosa), as the dominant algae in eutrophic water bodies, has caused a serious harm to the local eco-environment. A biological tool, employing allelopathic inhibitory of eucalyptus to control M. aeruginosa, has been receiving tremendous attention. This work presents the results of the allelopathic inhibitory effects of eucalyptus (Eucalyptus grandis × E.urophylla 'GLGU9') extracts of roots (ERE), stems (ESE), and leaves (ELE) on culture solutions of M. aeruginosa and its eco-physiological mechanism. The inhibitory effects of the extracts on the growth of M. aeruginosa varied greatly with ELE exhibiting the highest level of potency. Modes of action by which ELE inhibited M. aeruginosa growth were established. They involved reduction in photosynthesis, disruption of the cell membrane integrity, and inhibition of esterase activities of the cyanobacterial cells. However, ELE did not exhibit any gradients of toxicity towards zebrafish nor Washington grass plant. Species abundance and diversity in the systems remained likewise unaffected by ELE. The synergistic interaction between ELE and single-component allelochemicals (e.g., gallic acid and berberine) was ascribed to the increase in efficacy of allelochemicals in the various systems. The results of this study provide an underlying, novel, and attractive approach for controlling the growth of M. aeruginosa in aquatic environments.


Assuntos
Antibacterianos/farmacologia , Berberina/farmacologia , Eucalyptus/química , Ácido Gálico/farmacologia , Microcystis/crescimento & desenvolvimento , Feromônios/farmacologia , Extratos Vegetais/farmacologia , Alelopatia , Animais , Sinergismo Farmacológico , Esterases/antagonistas & inibidores , Microcystis/efeitos dos fármacos , Fotossíntese/efeitos dos fármacos , Folhas de Planta/química , Raízes de Plantas/química , Caules de Planta/química , Poaceae/efeitos dos fármacos , Washington , Peixe-Zebra/metabolismo
13.
Pestic Biochem Physiol ; 154: 32-38, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30765054

RESUMO

Cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), is a polyphagous lepidopteran pest distributed worldwide with a broad spectrum of host plants. However, the mechanism of H. armigera adaptation to various insecticides and defensive allelochemicals in its host plants is not fully understood. Therefore, this study examined the influence of consumption of plant allelochemicals on larval tolerance to methomyl and chlorpyrifos insecticides in H. armigera and its possible mechanism. Twelve plant allelochemicals were screened to evaluate their effects on larval sensitivity to methomyl. Of which flavone, coumarin, DIMBOA (2,4-Dihydroxy-7-methoxy-1,4-benzoxazin-3-one) and visnagin significantly reduced larval sensitivity to methomyl. Application of cytochrome P450 inhibitor piperonyl butoxide (PBO) significantly increased the mortality of methomyl-treated larvae. In contrast, PBO addition significantly decreased the mortality of chlorpyrifos-treated larvae. Moreover, allelochemical consumption enhanced the activities of glutathione S-transferase, carboxylesterase, cytochrome P450 and acetylcholinesterase in the midgut and fat body. The qRT-PCR analysis confirms that P450 genes, CYP6B2, CYP6B6 and CYP6B7 were induced by the four allelochemicals in the midguts and the fat bodies. In conclusion, the generalist H. armigera can take benefit of plant allelochemicals from its host plants to elaborate its defense against insecticides.


Assuntos
Resistência a Inseticidas/efeitos dos fármacos , Inseticidas/toxicidade , Larva/efeitos dos fármacos , Mariposas/efeitos dos fármacos , Feromônios/farmacologia , Compostos Fitoquímicos/farmacologia , Animais , Carboxilesterase/genética , Clorpirifos/toxicidade , Sistema Enzimático do Citocromo P-450/genética , Feminino , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Glutationa Transferase/genética , Proteínas de Insetos/genética , Resistência a Inseticidas/genética , Larva/genética , Masculino , Metomil/toxicidade , Mariposas/genética
14.
Pestic Biochem Physiol ; 154: 60-66, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30765057

RESUMO

Generalist phytophagous insects adapt to adventurous chemical environment in a wide variety of host plants by extraordinary detoxifying metabolic abilities. However, how polyphagous insect cope with the diversity of plant defenses remains largely unknown and only a few counter-defense genes detoxifying a wide range of toxic secondary metabolites have been well characterized. Here, we identify a cytochrome P450 gene (CYP6AB60) from tobacco cutworm (Spodoptera litura) in response to three different plant's defense metabolites. After being exposed to artificial diet supplemented with coumarin (COU), xanthotoxin (XAN) or tomatine (TOM), activities of P450 and CYP6AB60 transcript levels in both midgut and fat body tissues were significantly increased. Developmental expression analysis revealed that CYP6AB60 was expressed highly during the larval stages, and tissue distribution analysis showed that CYP6AB60 was expressed extremely high in the midgut, which correspond to the physiological role of CYP6AB60 from S. litura larvae in response to plant allelochemicals. Furthermore, when larvae are injected with double-stranded RNA (dsRNA) specific to CYP6AB60, levels of this transcript in the midgut and fatbody decrease and the negative effect of plant's defense metabolites on larval growth is magnified. These data demonstrate that the generalist insect S. litura might take advantage of an individual detoxificative gene CYP6AB60 to toxic secondary metabolites from different host plants. The CYP6AB60 can be a potential gene to carry out RNAi-mediated crop protection against the major polyphagous pest S. litura in the future.


Assuntos
Família 6 do Citocromo P450/genética , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Proteínas de Insetos/genética , Larva/efeitos dos fármacos , Feromônios/farmacologia , Spodoptera/efeitos dos fármacos , Animais , Cumarínicos/farmacologia , Tolerância a Medicamentos/genética , Larva/genética , Metoxaleno/farmacologia , Interferência de RNA , Spodoptera/genética , Tomatina/farmacologia
15.
Ticks Tick Borne Dis ; 10(3): 621-627, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30799282

RESUMO

Amblyomma sculptum is a tick affecting animal and human health across Argentina, Bolivia, Paraguay and Brazil. Donkeys, Equus asinus, are known to be resistant to A. sculptum, suggesting that they can produce non-host tick semiochemicals (allomones), as already demonstrated for some other vertebrate host/pest interactions, whereas horses, Equus caballus, are considered as susceptible hosts. In this study, we tested the hypothesis that donkeys produce natural repellents against A. sculptum, by collecting sebum from donkeys and horses, collecting the odour from sebum extracts, and identifying donkey-specific volatile compounds by gas chromatography (GC) and coupled GC-mass spectrometry (GC-MS). From the complex collected blends, five main compounds were identified in both species. Hexanal, heptanal and (E)-2-decenal were found predominantly in donkey extracts, whilst ethyl octanoate and ethyl decanoate were found predominantly in horse extracts. One compound, (E)-2-octenal, was detected exclusively in donkey extracts. In Y-tube olfactometer bioassays 36 different A. sculptum nymphs were tested for each extract, compound and concentration. The dry sebum extracts and the compounds identified in both species induced neither attraction nor repellency. Only (E)-2-octenal, the donkey-specific compound, displayed repellency, with more nymphs preferring the arm containing the solvent control when the compound was presented in the test arm across four concentrations tested (p < 0.05, Chi-square test). A combination of a tick attractant (ammonia) and (E)-2-octenal at 0.25 M also resulted in preference for the control arm (p < 0.05, Chi-square test). The use of semiochemicals (allomones) identified from less-preferred hosts in tick management has been successful for repelling brown dog ticks, Rhipicephalus sanguineus sensu lato from dog hosts. These results indicate that (E)-2-octenal could be used similarly to interfere in tick host location and be developed for use in reducing A. sculptum numbers on animal and human hosts.


Assuntos
Equidae/fisiologia , Repelentes de Insetos/isolamento & purificação , Feromônios/isolamento & purificação , Rhipicephalus sanguineus/efeitos dos fármacos , Sebo/química , Infestações por Carrapato/veterinária , Aldeídos/isolamento & purificação , Aldeídos/farmacologia , Alcenos/isolamento & purificação , Alcenos/farmacologia , Animais , Caprilatos/isolamento & purificação , Caprilatos/farmacologia , Cromatografia Gasosa , Decanoatos/isolamento & purificação , Decanoatos/farmacologia , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Cavalos/fisiologia , Repelentes de Insetos/farmacologia , Ninfa/efeitos dos fármacos , Feromônios/farmacologia , Infestações por Carrapato/prevenção & controle
16.
J Insect Sci ; 19(1)2019 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-30753607

RESUMO

The sweetpotato vine borer, Omphisa anastomosalis (Guenée), is a primarily Asian pest of sweetpotato, Ipomoea batatas L. Damage by O. anastomosalis infestation can cause root yield losses of 30%-50%. A binary sex pheromone for O. anastomosalis, consisting of Type I [(10E,14E)-10,14-hexadecadienal (E10,E14-16:Ald)] and Type II [(3Z,6Z,9Z)-3,6,9-tricosatriene (Z3,Z6,Z9-23:H)] components, was identified in Vietnam from extracts of female pheromone glands. A structurally similar Type II compound [(3Z,6Z,9Z)-3,6,9-docosatriene (Z3,Z6,Z9-22:H)], not recovered from female pheromone glands, was also found to synergize the attractiveness of the Type I component. Additional field work has been needed to determine whether these synergistic enhancements of attractiveness also occur in other parts of the geographical distribution of this moth species. Herein, results of studies are reported which document that both Z3,Z6,Z9-23:H and Z3,Z6,Z9-22:H also synergistically enhance male response to E10,E14-16:Ald in Hawaii sweetpotato field populations. Trap catch tends to be enhanced with increase of dose and lower Type I:Type II ratios. Among the compound doses and ratios tested, trap catch increased with the addition of the Type II component by over 13 times relative to traps baited with the Type I component alone, which significantly enhanced sweetpotato vine borer detection. Using a 2.0 mg: 4.0 mg Type I: Type II loading, there was continued catch over 12 wk, during which time the Type I component weathered at a faster rate than the Type II component. This binary sex pheromone seems to have promise for both monitoring and suppression of field populations of O. anastomosalis throughout its geographical range.


Assuntos
Aldeídos/farmacologia , Quimiotaxia , Mariposas/fisiologia , Feromônios/farmacologia , Polienos/farmacologia , Atrativos Sexuais/farmacologia , Animais , Feminino , Hawaii , Ipomoea batatas/crescimento & desenvolvimento
17.
J Insect Sci ; 19(1)2019 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-30794727

RESUMO

Stink bugs (Hemiptera: Pentatomidae) are economic pests in fruit, vegetable, grain, and row crops worldwide. Pyramid traps baited with lures of stink bug aggregation pheromones capture these pests in the field, but stink bugs can congregate on plants near traps. Our specific objective was to examine the area of arrestment of stink bugs based on their density on cotton at different distances from pheromone-baited traps. We used lures of the aggregation pheromone of Euschistus spp., methyl (2E,4Z)-2,4-decadienoate (MDD), and Plautia stali Scott, methyl [2E,4E,6Z]-2,4,6-decatrienoate (MDT). Overall, Euschistus servus (Say), Euschistus tristigmus (Say), Chinavia hilaris (Say), and Nezara viridula (L.) were the main stink bug species on cotton. Over the 3-yr study, adult stink bug density was significantly higher on the row of cotton immediately adjacent to a pheromone-baited trap than on the second and third row from the trap. Stink bug density was significantly lower on the seventh cotton row beyond the trap in 2015, on the fourth, eighth, and 16th rows in 2017, and on the fourth and eighth rows in 2018 compared to the two or three rows nearest the trap. These results indicate that adult stink bugs congregated mainly on the three cotton rows (2.73 m in width) nearest a trap. Management strategies utilizing pheromone-baited traps for stink bug control, such as trap cropping in combination with traps, should take into consideration this area of arrestment.


Assuntos
Quimiotaxia , Decanoatos/farmacologia , Heterópteros/fisiologia , Feromônios/farmacologia , Animais , Gossypium/crescimento & desenvolvimento , Controle de Insetos , Densidade Demográfica
18.
Protoplasma ; 256(3): 857-871, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30656457

RESUMO

The stress induced by allelochemicals present in stem aqueous extract (SAE) of Nicotiana plumbaginifolia on alterations in growth, ultrastructure on Cassia tora L., and mitotic changes on Allium cepa L. were inspected. Application of SAE at different concentrations (0.5, 1, 2, and 4%) expressively reduced the growth of C. tora in terms of seedling length and dry biomass. Moreover, the ultrastructural variations induced in the epidermis of Cassia leaf (adaxial and abaxial surface) of 15-day-old saplings were analyzed through scanning electron microscopy (SEM). The variations noticed are rupturing and shrinking of cells along epidermis; damaged margins, extensively curled leaf apex along with the appearance of puff-like structures, grooves, and thread-like structures on the leaf surface. The epidermal cells of samples exposed to treatment no longer appear smooth relative to control, besides showing necrosis as well. Upon exposure to different concentrations of extract, A. cepa root tip cells showed aberrations in chromosome arrangement and disparity in the shape of the interphase and prophase nuclei along various phases of mitotic cycle as compared to control. The mitotic index (MI) showed a concentration-dependent decline in onion root tips exposed to SAE. The aberrations appearing frequently were formation of multinucleated cells, sticky metaphase and anaphase with bridges, sticky telophase, disturbed polarity, etc. The results also show the induction of elongated cells, giant cells, and cells with membrane damage by extract treatment. To our knowledge, this is the first gas chromatography-mass spectrometry (GC-MS) analysis of the methanolic extract of N. plumbaginifolia stem. Overall, 62 compounds were reported, covering 99.61% of the entire constituents, which can be considered responsible for the allelopathic suppression of C. tora. The chief component was 4-tert-butylcalix[4]arene with the highest composition of 19.89%, followed by palmitic acid (12.25%), palmitoleic acid (8.23%), precocene 2 (7.53%), isophytyl acetate (4.01%), and betastigmasterol (3.95%).


Assuntos
Alelopatia/efeitos dos fármacos , Cassia/citologia , Cassia/ultraestrutura , Mitose/efeitos dos fármacos , Cebolas/citologia , Feromônios/farmacologia , Plantas Daninhas/efeitos dos fármacos , Biomassa , Cassia/efeitos dos fármacos , Morte Celular/efeitos dos fármacos , Tamanho Celular , Cromossomos de Plantas/genética , Concentração de Íons de Hidrogênio , Índice Mitótico , Osmose , Extratos Vegetais/farmacologia , Raízes de Plantas/citologia , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Caules de Planta/química , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/química
19.
PLoS Negl Trop Dis ; 13(1): e0006948, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30668561

RESUMO

The human disease schistosomiasis (or bilharzia) is caused by the helminth blood fluke parasite Schistosoma mansoni, which requires an intermediate host, the freshwater gastropod snail Biomphalaria glabrata (the most common intermediate host). The free-swimming parasite miracidia utilise an excellent chemosensory sense to detect and locate an appropriate host. This study investigated the biomolecules released by the snail that stimulate changes in the behaviour of the aquatic S. mansoni miracidia. To achieve this, we have performed an integrated analysis of the snail-conditioned water, through chromatography and bioassay-guided behaviour observations, followed by mass spectrometry. A single fraction containing multiple putative peptides could stimulate extreme swimming behaviour modifications (e.g. velocity, angular variation) similar to those observed in response to crude snail mucus. One peptide (P12;-R-DITSGLDPEVADD-KR-) could replicate the stimulation of miracidia behaviour changes. P12 is derived from a larger precursor protein with a signal peptide and multiple dibasic cleavage sites, which is synthesised in various tissues of the snail, including the central nervous system and foot. P12 consists of an alpha helix secondary structure as indicated by circular dichroism spectroscopy. This information will be helpful for the development of approaches to manipulate this parasites life cycle, and opens up new avenues for exploring other parasitic diseases which have an aquatic phase using methods detailed in this investigation.


Assuntos
Agentes de Controle Biológico/farmacologia , Biomphalaria/química , Descoberta de Drogas/métodos , Peptídeos/farmacologia , Feromônios/farmacologia , Schistosoma mansoni/efeitos dos fármacos , Animais , Anti-Helmínticos/farmacologia , Humanos , Esquistossomose/tratamento farmacológico
20.
Pest Manag Sci ; 75(1): 152-159, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29797492

RESUMO

BACKGROUND: The expression of P450 genes in insects can be induced by plant allelochemicals. To understand the induction mechanisms, we measured the expression profiles of three P450 genes and their promoter activities under the induction of plant allelochemicals. RESULTS: The inducible expression of CYP6CY19 was the highest among three genes, followed by those of CYP6CY22 and CYP6DA1. The regions from -687 to +586 bp of CYP6DA1, from -666 to +140 bp of CYP6CY19 and from -530 to +218 bp of CYP6CY22 were essential for basal transcriptional activity. The cis-elements for plant allelochemicals induction were identified between -193 and +56 bp of CYP6DA1, between -157 and +140 bp of CYP6CY19 and between -108 and +218 bp of CYP6CY22. These promoter regions were found to contain a potential aryl hydrocarbon receptor element binding site with a conservative sequence motif 5'-C/TAC/ANCA/CA-3'. All these four plant allelochemicals were able to induce the expression of these P450 genes. Tannic acid had a better inductive effect than other three plant allelochemicals. CONCLUSIONS: Our study identified the plant allelochemical responsive cis-elements. This provides further research targets aimed at understanding the regulatory mechanisms of P450 genes expression and their interactions with plant allelochemicals in insect pests. © 2018 Society of Chemical Industry.


Assuntos
Afídeos/efeitos dos fármacos , Afídeos/genética , Família 6 do Citocromo P450/genética , Proteínas de Insetos/genética , Feromônios/farmacologia , Animais , Afídeos/metabolismo , Família 6 do Citocromo P450/metabolismo , Gossipol/farmacologia , Proteínas de Insetos/metabolismo , Cetonas/farmacologia , Regiões Promotoras Genéticas , Quercetina/farmacologia , Taninos/farmacologia
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