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1.
Pestic Biochem Physiol ; 173: 104777, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33771256

RESUMO

Ceratocystis fimbriata is the pathogen of black rot disease, which widely exists in sweet potato producing areas all over the world. The antifungal activity of volatile organic compounds (VOCs) released by Pseudomonas chlororaphis subsp. aureofaciens SPS-41 against C. fimbriata was reported in our previous study. In this study, we attempted to reveal the underlying antifungal mechanism of SPS-41 volatiles. Our results showed that the VOCs released by SPS-41 caused the morphological change of hyphae, destroyed the integrity of cell membrane, reduced the content of ergosterol, and induced massive accumulation of reactive oxygen species in C. fimbriata cells. Furthermore, SPS-41 fumigation decreased the mitochondrial membrane potential, acetyl-CoA and pyruvate content of C. fimbriata cells, as well as the mitochondrial dehydrogenases activity. In addition, the VOCs generated by SPS-41 reduced the intracellular ATP content and increased the extracellular ATP content of C. fimbriata. In summary, SPS-41 fumigation exerted its antifungal activity by inducing oxidative stress and mitochondrial dysfunction in C. fimbriata.


Assuntos
Ascomicetos , Compostos Orgânicos Voláteis , Antifúngicos/farmacologia , Mitocôndrias , Estresse Oxidativo , Doenças das Plantas , Pseudomonas , Compostos Orgânicos Voláteis/farmacologia
2.
Molecules ; 26(4)2021 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-33562272

RESUMO

For many antibacterial polymer fibres, especially for those with natural functional additives, the antibacterial response might not last over time. Moreover, the mechanical performance of polymeric fibres degrades significantly during the intended operation, such as usage in textile and industrial filter applications. The degradation process and overall ageing can lead to emitted volatile organic compounds (VOCs). This work focused on the usage of pine rosin as natural antibacterial chemical and analysed the weathering of melt-spun polyethylene (PE) and poly lactic acid (PLA) polyfilaments. A selected copolymer surfactant, as an additional chemical, was studied to better integrate rosin with the molecular structure of the plastics. The results reveal that a high 20 w-% of rosin content can be obtained by surfactant addition in non-oriented PE and PLA melt-spun polyfilaments. According to the VOC analysis, interestingly, the total emissions from the melt-spun PE and PLA fibres were lower for rosin-modified (10 w-%) fibres and when analysed below 60 ℃. The PE fibres of the polyfilaments were found to be clearly more durable in terms of the entire weathering study, i.e., five weeks of ultraviolet radiation, thermal ageing and standard washing. The antibacterial response against Gram-positive Staphylococcus aureus by the rosin-containing fibres was determined to be at the same level (decrease of 3-5 logs cfu/mL) as when using 1.0 w-% of commercial silver-containing antimicrobial. For the PE polyfilaments with rosin (10 w-%), full killing response (decrease of 3-5 logs cfu/mL) remained after four weeks of accelerated ageing at 60 ℃.


Assuntos
Antibacterianos/química , Polietileno/química , Resinas Vegetais/química , Compostos Orgânicos Voláteis/química , Antibacterianos/farmacologia , Testes de Sensibilidade Microbiana , Pinus/química , Plásticos/química , Plásticos/farmacologia , Poliésteres/química , Polietileno/farmacologia , Polímeros/química , Polímeros/farmacologia , Prata/química , Staphylococcus aureus/efeitos dos fármacos , Têxteis/análise , Compostos Orgânicos Voláteis/farmacologia
3.
Food Chem ; 337: 127774, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-32777570

RESUMO

Apis cerana honey collected from the Qinling Mountains in China has been widely used for its antimicrobial property in traditional Chinese medicine. However, its antibacterial mechanism against Salmonella Typhimurium LT2 is still uncertain. A total of 52 volatile components were identified using headspace-gas-chromatography-ion-mobility, and Qinling A. cerana honey exhibited more abundant aromas than monofloral honeys. The phenolic extracts of honey sample F exhibited the lowest minimum inhibitory concentration (5 mg/mL), and chlorogenic acid exhibited the highest (155.91 ± 0.79 mg/kg), followed by caffeic acid, and rutin. After being treated with the extract, cell membranes of S. Typhimurium LT2 significantly shrunk and further collapsed. The extract treatment on mice caused a significant decrease in S. Typhimurium LT2, and a dramatic increase in the potential prebiotic Lactobacillus in both the caecum and colon. The results demonstrate that the Qinling A. cerana honey extract could effectively inhibit S. Typhimurium in vitro and in vivo.


Assuntos
Anti-Infecciosos/farmacologia , Mel/análise , Salmonella typhimurium/efeitos dos fármacos , Salmonella typhimurium/patogenicidade , Compostos Orgânicos Voláteis/química , Animais , Anti-Infecciosos/química , Anti-Infecciosos/uso terapêutico , Abelhas , Modelos Animais de Doenças , Cromatografia Gasosa-Espectrometria de Massas , Camundongos , Testes de Sensibilidade Microbiana , Fenóis/química , Infecções por Salmonella/tratamento farmacológico , Compostos Orgânicos Voláteis/farmacologia , Compostos Orgânicos Voláteis/uso terapêutico
4.
Molecules ; 26(1)2020 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-33374682

RESUMO

Seven endophytic fungi were isolated from the tropical medicinal plant Piper longum L. After preliminary screening, Phomopsis heveicola was selected for the epigenetic activation treatments. The antibacterial, antifungal, and antioxidant potentials of crude extracts obtained from the treatments (with and without epigenetic modifiers) were analyzed in vitro. The extracts inhibited growth of the human pathogens Pseudomonas aeruginosa, Shigella sonnei, Streptococcus pyogenes, and Salmonella typhi, as well as the phytopathogens Puccinia recondita, Rhizoctonia solani, Phytophthora infestans, and Botrytis cinerea. Furthermore, DPPH-scavenging activity was higher in valproic acid treated extracts. Volatile chemicals with known biological activities (measured with GC-MS/MS), were released in the valproic acid treatment. The antimicrobial potentials of the extracts were confirmed using MRM/MS analysis. The experiments revealed a new promising endophytic fungus, P. heveicola, to be utilized in biological plant protection and in biomedical applications.


Assuntos
Anti-Infecciosos/farmacologia , Endófitos/química , Epigenômica , Compostos Fitoquímicos/farmacologia , Piper/química , Extratos Vegetais/farmacologia , Compostos Orgânicos Voláteis/farmacologia , Antioxidantes/farmacologia , Bactérias/efeitos dos fármacos , Fungos/efeitos dos fármacos , Compostos Orgânicos Voláteis/análise
5.
Nat Commun ; 11(1): 4608, 2020 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-32929085

RESUMO

Actinobacteria produce antibacterial and antifungal specialized metabolites. Many insects harbour actinobacteria on their bodies or in their nests and use these metabolites for protection. However, some actinobacteria produce metabolites that are toxic to insects and the evolutionary relevance of this toxicity is unknown. Here we explore chemical interactions between streptomycetes and the fruit fly Drosophila melanogaster. We find that many streptomycetes produce specialized metabolites that have potent larvicidal effects against the fly; larvae that ingest spores of these species die. The mechanism of toxicity is specific to the bacterium's chemical arsenal: cosmomycin D producing bacteria induce a cell death-like response in the larval digestive tract; avermectin producing bacteria induce paralysis. Furthermore, low concentrations of volatile terpenes like 2-methylisoborneol that are produced by streptomycetes attract fruit flies such that they preferentially deposit their eggs on contaminated food sources. The resulting larvae are killed during growth and development. The phenomenon of volatile-mediated attraction and specialized metabolite toxicity suggests that some streptomycetes pose an evolutionary risk to insects in nature.


Assuntos
Bactérias/metabolismo , Drosophila melanogaster/citologia , Drosophila melanogaster/microbiologia , Actinobacteria/fisiologia , Animais , Antraciclinas/farmacologia , Antibacterianos/química , Antibacterianos/farmacologia , Canfanos/toxicidade , Morte Celular/efeitos dos fármacos , Drosophila melanogaster/efeitos dos fármacos , Larva/efeitos dos fármacos , Larva/microbiologia , Metaboloma , Esporos Bacterianos/metabolismo , Esporos Bacterianos/fisiologia , Streptomyces/fisiologia , Análise de Sobrevida , Compostos Orgânicos Voláteis/farmacologia
6.
PLoS Pathog ; 16(9): e1008800, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32913361

RESUMO

Soil-dwelling animals are at risk of pathogen infection in soils. When choosing nesting sites, animals could reduce this risk by avoiding contact with pathogens, yet there is currently little evidence. We tested this hypothesis using Solenopsis invicta as a model system. Newly mated queens of S. invicta were found to nest preferentially in soil containing more actinobacteria of Streptomyces and Nocardiopsis and to be attracted to two volatiles produced by these bacteria, geosmin and 2-methylisoborneol. Actinobacteria-rich soil was favored by S. invicta and this soil contained fewer putative entomopathogenic fungi than adjacent areas. Queens in such soil benefited from a higher survival rate. In culture, isolated actinobacteria inhibited entomopathogenic fungi, suggested that their presence may reduce the risk of fungal infection. These results indicated a soil-dwelling ant may choose nest sites presenting relatively low pathogen risk by detecting the odors produced by bacteria with anti-fungal properties.


Assuntos
Actinobacteria/fisiologia , Anti-Infecciosos/farmacologia , Formigas/fisiologia , Fungos/efeitos dos fármacos , Micoses/prevenção & controle , Comportamento de Nidação/efeitos dos fármacos , Compostos Orgânicos Voláteis/farmacologia , Animais , Formigas/microbiologia , Micoses/microbiologia , Microbiologia do Solo , Simbiose
7.
PLoS One ; 15(8): e0237353, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32785255

RESUMO

Airborne spatial repellency (SR) is characterized and distinguished from other chemical actions including contact locomotor excitation and toxicity. The use of volatile spatial repellents is a potential new intervention class for combatting mosquito-borne pathogen transmission; therefore, continuing investigations on the actions of these chemicals that modify mosquito host-seeking behavior (i.e., bite prevention) is needed. The objective of this study is to characterize the key behavioral avoidance actions of transfluthrin (TFT) to advance spatial repellent development into practical products. Behavioral avoidance responses were observed for adult laboratory strains of Aedes aegypti, Anopheles minimus and An. dirus, and two field populations of An. harrisoni and Ae. aegypti, respectively. Established TFT sublethal (LC50 and LC75), lethal concentrations (LC99) and discriminating concentrations (DCs) were selected corresponding to each mosquito test species. Spatial repellency and contact excitation ('irritancy') responses on adult mosquitoes to TFT were assessed using an excito-repellency assay system. At LC50, TFT exhibited strong avoidance with An. minimus (60.1% escape) and An. dirus (80% escape) laboratory strains, showing between 12 and 16x greater escape response than Ae. aegypti (5% escape). Repellency responses for field collected Ae. aegypti and An. harrisoni were 54.9 and 47.1% escape, respectively. After adjusting the initial contact escape response (a measure of combined irritancy and repellency) to estimate only escape due to contact, the LC50 and LC99 showed moderate escape irritancy with laboratory Ae. aegypti (41.4% escape) and no contact activity against the field population. Adjustment showed only weak contact activity (16.1% escape) in laboratory An. minimus at LC50. Spatial repellency is the predominant mode of action of TFT among colonized and field mosquitoes used in this study. Established baseline (susceptible) dose-response curves assist in optimizing SR products for mosquito control and pathogen transmission prevention.


Assuntos
Comportamento Animal/efeitos dos fármacos , Ciclopropanos/farmacologia , Fluorbenzenos/farmacologia , Repelentes de Insetos/farmacologia , Mosquitos Vetores/efeitos dos fármacos , Compostos Orgânicos Voláteis/farmacologia , Aedes/efeitos dos fármacos , Aedes/fisiologia , Animais , Anopheles/efeitos dos fármacos , Anopheles/fisiologia , Aprendizagem da Esquiva , Relação Dose-Resposta a Droga , Feminino , Controle de Mosquitos/métodos , Mosquitos Vetores/fisiologia , Doenças Transmitidas por Vetores/prevenção & controle
8.
PLoS One ; 15(7): e0235630, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32628739

RESUMO

In several phytophagous hemipterans, behavior appears to be mediated by both visual and chemical cues. For the Asian citrus psyllid (ACP) Diaphorina citri (Hemiptera: Liviidae), olfactometric assays are generally difficult to interpret owing to the low proportion of individuals responding to odors (~30-40%), which compromises the efficiency and reliability of the results of behavioral tests. In the present study, the ACP behavioral response to emitted odors from sweet orange (Citrus sinensis L. Osbeck) flushes in a 4-arm olfactometer using different colors (four white-, two white- and two yellow- on opposite sides, or four yellow-colored fields), and the role of the airflow in the concentration of volatile organic compounds (VOCs) were assessed at two airflows [0.4 and 0.1 L/min (LPM)]. Exposure to 'Pera' sweet orange or clean air in treatments with four yellow-colored-fields increased the response rate of ACP females to the odor sources compared with exposure to 'Pera' sweet orange or clean air in treatments with four white-colored-fields, independently of the odor source and airflow tested. For the assays using two white- and two yellow-colored fields on opposite sides and 0.4 or 0.1 LPM airflow, the residence time of ACP females to odors ('Pera' sweet orange or clean air) was similar or higher in treatments using yellow- than those using white-colored fields. For both assays (VOCs and olfactometric behavioral parameters), the reduction in airflow from 0.4 to 0.1 LPM greatly changed the airborne concentration and ACP behavior. Quantitative chemical analyses revelead that the concentration of most compounds emitted by 'Pera' sweet orange flushes for the headspace using 0.1 LPM airflow were greater than the concentrations measured using 0.4 LPM airflow. Therefore, this treatment design provides an useful tool to assess the ACP behavioral response to the odors from citrus plants, and it can also help in the discrimination of dose-response screenings for VOCs or conspecific insects.


Assuntos
Ar , Comportamento Animal/efeitos dos fármacos , Citrus/metabolismo , Hemípteros/efeitos dos fármacos , Hemípteros/fisiologia , Olfato , Compostos Orgânicos Voláteis/farmacologia , Animais , Cor , Relação Dose-Resposta a Droga , Compostos Orgânicos Voláteis/metabolismo
9.
Can J Microbiol ; 66(10): 593-599, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32485113

RESUMO

Pseudogymnoascus destructans, the fungal pathogen that causes white-nose syndrome, has killed millions of bats across eastern North America and continues to threaten new bat populations. The spread and persistence of P. destructans has likely been worsened by the ability of this fungus to grow as a saprotroph in the hibernaculum environment. Reducing the environmental growth of P. destructans may improve bat survival. Volatile organic compounds (VOCs) are attractive candidates to target environmental P. destructans, as they can permeate through textured environments that may be difficult to thoroughly contact with other control mechanisms. We tested in hibernaculum sediment the performance of VOCs that were previously shown to inhibit P. destructans growth in agar cultures and examined the inhibition kinetics and specificity of these compounds. Three VOCs, 2-methyl-1-butanol, 2-methyl-1-propanol, and 1-pentanol, were fungicidal towards P. destructans in hibernaculum sediment, fast-acting, and had greater effects against P. destructans than other Pseudogymnoascus species. Our results suggest that use of these VOCs may be considered further as an effective management strategy to reduce the environmental exposure of bats to P. destructans in hibernacula.


Assuntos
Ascomicetos/efeitos dos fármacos , Fungicidas Industriais/farmacologia , Sedimentos Geológicos/microbiologia , Compostos Orgânicos Voláteis/farmacologia , Animais , Ascomicetos/fisiologia , Quirópteros/microbiologia , Doenças Nasais/microbiologia , Doenças Nasais/veterinária
10.
Sci Rep ; 10(1): 6547, 2020 04 16.
Artigo em Inglês | MEDLINE | ID: mdl-32300135

RESUMO

Microbial volatile compounds (MVCs) significantly influence the growth of plants and phytopathogens. However, the practical application of MVCs at the field level is limited by the fact that the concentrations at which these compounds antagonize the pathogens are often toxic for the plants. In this study, we investigated the effect of dimethyl disulfide (DMDS), one of the MVCs produced by microorganisms, on the fitness of tomato plants and its fungicidal potential against a fungal phytopathogen, Sclerotinia minor. DMDS showed strong fungicidal and plant growth promoting activities with regard to the inhibition of mycelial growth, sclerotia formation, and germination, and reduction of disease symptoms in tomato plants infected with S. minor. DMDS exposure significantly upregulated the expression of genes related to growth and defense against the pathogen in tomato. Especially, the overexpression of PR1 and PR5 suggested the involvement of the salicylic acid pathway in the induction of systemic resistance. Several morphological and ultrastructural changes were observed in the cell membrane of S. minor and the expression of ergosterol biosynthesis gene was significantly downregulated, suggesting that DMDS damaged the membrane, thereby affecting the growth and pathogenicity of the fungus. In conclusion, the tripartite interaction studies among pathogenic fungus, DMDS, and tomato revealed that DMDS played roles in antagonizing pathogen as well as improving the growth and disease resistance of tomato. Our findings provide new insights into the potential of volatile DMDS as an effective tool against sclerotial rot disease.


Assuntos
Antifúngicos/farmacologia , Ascomicetos/fisiologia , Membrana Celular/patologia , Resistência à Doença , Dissulfetos/farmacologia , Interações Hospedeiro-Patógeno , Doenças das Plantas/microbiologia , Ascomicetos/efeitos dos fármacos , Ascomicetos/ultraestrutura , Membrana Celular/efeitos dos fármacos , Família 51 do Citocromo P450/metabolismo , Ergosterol/análise , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Glucanos/metabolismo , Interações Hospedeiro-Patógeno/efeitos dos fármacos , Peróxido de Hidrogênio/metabolismo , Lycopersicon esculentum/efeitos dos fármacos , Lycopersicon esculentum/genética , Lycopersicon esculentum/crescimento & desenvolvimento , Lycopersicon esculentum/microbiologia , Testes de Sensibilidade Microbiana , Controle Biológico de Vetores , Transcrição Genética/efeitos dos fármacos , Compostos Orgânicos Voláteis/farmacologia
11.
Sci Rep ; 10(1): 6512, 2020 04 16.
Artigo em Inglês | MEDLINE | ID: mdl-32300184

RESUMO

Sustainable, low impact control methods, including mating disruption and microbial insecticides against L. botrana have been available for decades. Yet, successful implementation has been restricted to only a few grapevine districts in the world. A limiting factor is the lack of a female attractant to either monitor or control the damaging sex. Volatile attractants for both female and male insects can be used to assess when L. botrana populations exceed economic thresholds, and to decrease the use of synthetic pesticides within both conventional and pheromone programs. Rather than using host-plant volatiles, which are readily masked by background volatiles released by the main crop, we tested the attractiveness of volatiles that signify microbial breakdown and more likely stand out against the background odour. A two-component blend of 2-phenylethanol (2-PET) and acetic acid (AA) caught significant numbers of both sexes. Catches increased with AA and, to a minimal extent, 2-PET loads. However, a higher load of 2-PET also increased bycatches, especially of Lepidoptera and Neuroptera. Major (ethanol, ethyl acetate, 3-methyl-1-butanol) or minor (esters, aldehydes, alcohols and a ketone) fermentation volatiles, did surprisingly not improve the attraction of L. botrana compared to the binary blend of 2-PET and AA alone, but strongly increased bycatches. The most attractive lure may thus not be the best choice in terms of specificity. We suggest that future research papers always disclose all bycatches to permit evaluation of lures in terms of sustainability.


Assuntos
Lepidópteros/efeitos dos fármacos , Odorantes , Comportamento Sexual Animal/efeitos dos fármacos , Compostos Orgânicos Voláteis/farmacologia , Ácido Acético/química , Ácido Acético/farmacologia , Animais , Feminino , Humanos , Lepidópteros/patogenicidade , Lepidópteros/fisiologia , Masculino , Controle de Pragas , Praguicidas/química , Praguicidas/farmacologia , Álcool Feniletílico/química , Álcool Feniletílico/farmacologia , Feromônios/antagonistas & inibidores , Feromônios/metabolismo , Atrativos Sexuais/química , Atrativos Sexuais/farmacologia , Especificidade da Espécie , Vitis/parasitologia , Compostos Orgânicos Voláteis/química
12.
BMC Complement Med Ther ; 20(1): 109, 2020 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-32276586

RESUMO

BACKGROUND: Ligularia fischeri (Ledeb) Turcz (LFT) is a well-known expectorant and active anti-inflammatory agent in Chinese traditional medicine. LFT's expectorant effect is closely related to its anti-inflammatory effects. This study aimed to evaluate the differential composition and anti-inflammatory mechanisms of the volatile components in LFT from different production areas. METHOD: Headspace solid-phase microextraction-gas chromatography-mass spectrometry analysis of volatile components, as well as chemometric methods, including similarity analysis, hierarchical clustering analysis, and principal component analysis, were performed to identify LFT produced in different areas. The molecular mechanism underlying the anti-inflammatory effects of these components was determined by network pharmacology analysis. RESULTS: We observed significant differences in the chemical constituents and percentage contents in samples with different origins. Eighteen volatile components were identified in four different producing areas, among which the highest content of olefinic components was the main component of the aroma of LFT. The mechanisms of these pharmacological effects involved multiple targets and pathways. Twenty-seven potential target proteins and 65 signaling pathways were screened, and a "component-target-disease" interaction network map was constructed. The volatile components of the LFT function mainly by inhibiting the production of inflammatory factors. CONCLUSION: This study provides a theoretical framework for further development and application of LFT used in traditional Chinese medicine.


Assuntos
Anti-Inflamatórios/farmacologia , Ligularia/química , Extratos Vegetais/farmacologia , Compostos Orgânicos Voláteis/farmacologia , Anti-Inflamatórios/química , China , Cromatografia Gasosa-Espectrometria de Massas , Estrutura Molecular , Extratos Vegetais/química , Raízes de Plantas/química , Mapas de Interação de Proteínas , Microextração em Fase Sólida , Compostos Orgânicos Voláteis/química
13.
Sci Rep ; 10(1): 4498, 2020 03 11.
Artigo em Inglês | MEDLINE | ID: mdl-32161291

RESUMO

Volatile organic compounds (VOCs) produced by Aureobasidium pullulans were investigated for antagonistic actions against Alternaria alternata and Botrytis cinerea. Conidia germination and colony growth of these two phytopathogens were suppressed by A. pullulans VOCs. A novel experimental setup was devised to directly extract VOCs using solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) from antagonist-pathogen culture headspace. The proposed system is a robust method to quantify microbial VOCs using an internal standard. Multivariate curve resolution-alternating least squares deconvolution of SPME-GC-MS spectra identified fourteen A. pullulans VOCs. 3-Methyl-1-hexanol, acetone, 2-heptanone, ethyl butyrate, 3-methylbutyl acetate and 2-methylpropyl acetate were newly identified in A. pullulans headspace. Partial least squares discriminant analysis models with variable importance in projection and selectivity ratio identified four VOCs (ethanol, 2-methyl-1-propanol, 3-methyl-1-butanol and 2-phenylethanol), with high explanatory power for discrimination between A. pullulans and pathogen. The antifungal activity and synergistic interactions of the four VOCs were evaluated using a Box-Behnken design with response surface modelling. Ethanol and 2-phenylethanol are the key inhibitory A. pullulans VOCs against both B. cinerea and A. alternata. Our findings introduce a novel, robust, quantitative approach for microbial VOCs analyses and give insights into the potential use of A. pullulans VOCs to control B. cinerea and A. alternata.


Assuntos
Alternaria/efeitos dos fármacos , Ascomicetos/química , Botrytis/efeitos dos fármacos , Cromatografia Gasosa-Espectrometria de Massas , Microextração em Fase Sólida , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/farmacologia , Antifúngicos/química , Antifúngicos/farmacologia , Metabolômica/métodos , Testes de Sensibilidade Microbiana
14.
Sci Rep ; 10(1): 4303, 2020 03 09.
Artigo em Inglês | MEDLINE | ID: mdl-32152427

RESUMO

Single substances within complex vertebrate chemical signals could be physiologically or behaviourally active. However, the vast diversity in chemical structure, physical properties and molecular size of semiochemicals makes identifying pheromonally active compounds no easy task. Here, we identified two volatile cyclic dipeptides, cyclo(L-Leu-L-Pro) and cyclo(L-Pro-L-Pro), from the complex mixture of a chemical signal in terrestrial vertebrates (lizard genus Sceloporus), synthesised one of them and investigated their biological activity in male intra-specific communication. In a series of behavioural trials, lizards performed more chemosensory behaviour (tongue flicks, lip smacks and substrate lickings) when presented with the synthesised cyclo(L-Pro-L-Pro) chemical blend, compared to the controls, the cyclo(L-Leu-L-Pro) blend, or a combined blend with both cyclic dipeptides. The results suggest a potential semiochemical role of cyclo(L-Pro-L-Pro) and a modulating effect of cyclo(L-Leu-L-Pro) that may depend on the relative concentration of both compounds in the chemical signal. In addition, our results stress how minor compounds in complex mixtures can produce a meaningful behavioural response, how small differences in structural design are crucial for biological activity, and highlight the need for more studies to determine the complete functional landscape of biologically relevant compounds.


Assuntos
Comportamento Animal/efeitos dos fármacos , Quimiotaxia , Dipeptídeos/farmacologia , Glândulas Exócrinas/metabolismo , Peptídeos Cíclicos/farmacologia , Compostos Orgânicos Voláteis/farmacologia , Animais , Dipeptídeos/química , Glândulas Exócrinas/efeitos dos fármacos , Lagartos , Peptídeos Cíclicos/química , Compostos Orgânicos Voláteis/química
15.
PLoS Negl Trop Dis ; 14(3): e0007719, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32126087

RESUMO

The putative vector of trachoma, Musca sorbens, prefers to lay its eggs on human faeces on the ground. This study sought to determine whether M. sorbens females were attracted to volatile odours from human faeces in preference to odours from the faeces of other animals, and to determine whether specific volatile semiochemicals mediate selection of the faeces. Traps baited with the faeces of humans and local domestic animals were used to catch flies at two trachoma-endemic locations in The Gambia and one in Ethiopia. At all locations, traps baited with faeces caught more female M. sorbens than control traps baited with soil, and human faeces was the most successful bait compared with soil (mean rate ratios 44.40, 61.40, 10.50 [P<0.001]; 8.17 for child faeces [P = 0.004]). Odours from human faeces were sampled by air entrainment, then extracts of the volatiles were tested by coupled gas chromatography-electroantennography with laboratory-reared female M. sorbens. Twelve compounds were electrophysiologically active and tentatively identified by coupled mass spectrometry-gas chromatography, these included cresol, indole, 2-methylpropanoic acid, butanoic acid, pentanoic acid and hexanoic acid. It is possible that some of these volatiles govern the strong attraction of M. sorbens flies to human faeces. If so, a synthetic blend of these chemicals, at the correct ratios, may prove to be a highly attractive lure. This could be used in odour-baited traps for monitoring or control of this species in trachoma-endemic regions.


Assuntos
Fezes/química , Insetos Vetores/efeitos dos fármacos , Muscidae/efeitos dos fármacos , Feromônios/farmacologia , Compostos Orgânicos Voláteis/farmacologia , Adolescente , Adulto , Animais , Criança , Cromatografia Gasosa , Fenômenos Eletrofisiológicos , Etiópia , Feminino , Gâmbia , Humanos , Insetos Vetores/fisiologia , Masculino , Muscidae/fisiologia , Feromônios/isolamento & purificação , Compostos Orgânicos Voláteis/isolamento & purificação , Adulto Jovem
16.
Microbiol Res ; 236: 126436, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32179388

RESUMO

Trichoderma longibrachiatum EF5 is an endophytic fungal antagonist of rice. It is used for the control of soil-borne fungal pathogens-Sclerotium rolfsii and Macrophomina phaseolina. We demonstrate that T. longibrachiatum EF5 inhibits the growth of these pathogens on direct interaction as well as via the production of the microbial volatile organic compounds (mVOCs). The mVOCs reduced mycelial growth and inhibited the production of sclerotia by altering the mycelial structure. We profiled 138 mVOCs, when T. longibrachiatum EF5 interacted with the two pathogens. During these interactions, several compounds are up- or downregulated by T. longibrachiatum EF5, including longifolene, caryophyllene,1-Butanol 2-methyl, cedrene, and cuprenene. These compounds are involved in the biosynthetic pathways of the sesquiterpenoid and alkane, and the degradation pathway of trimethylamine. We provide an insight into the multiple modes by which T. longibrachiatum EF5 exerts antagonistic actions, such as hyperparasitism, competitions, and antibiosis via mVOCs. In contrast to their antimicrobial properties, these metabolites could also promote plant growth.


Assuntos
Agaricales/efeitos dos fármacos , Antibiose , Ascomicetos/efeitos dos fármacos , Trichoderma/metabolismo , Compostos Orgânicos Voláteis/farmacologia , Agaricales/crescimento & desenvolvimento , Ascomicetos/crescimento & desenvolvimento , Agentes de Controle Biológico , Interações Microbianas , Doenças das Plantas/microbiologia , Microbiologia do Solo , Compostos Orgânicos Voláteis/química
17.
J Chem Ecol ; 46(2): 176-185, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32062821

RESUMO

Females of the Queensland fruit fly (QFF), Bactrocera tryoni, are amongst the most damaging pests of horticulture in Australia and neighboring countries. Females can lay eggs into more than a hundred species of fruits and vegetables, resulting in large crop losses. Sexually mature males can be managed sustainably with traps baited with long-lasting synthetic lures, and sexually immature males and females can be attracted and killed by short-lived protein baits applied directly on surfaces, with a low success rate (< 20%). No long-lasting attractants for virgin or mated females exist. With the aim of developing a female attractant for surveillance, we collected and analyzed the odors of four ripe host fruits: orange, cherry guava, banana and feijoa. Virgin and mated female QFF were tested with gas-chromatography coupled with electro-antennographic detection to identify electrophysiologically (EAD)-active compounds. We detected 41 EAD-active compounds, with seven found common for more than one fruit. Overall, mated females responded more often and with higher intensity than virgin females. In particular, five compounds present either in cherry guava or feijoa triggered a significantly higher EAD response from mated females than from virgins. Twenty-six EAD-active compounds were selected and tested individually in a Y-tube olfactometer to measure attraction of both virgin and mated females. Behavioral responses differed significantly amongst the compounds, but not strongly between virgin and mated females. We did not find any correlation between electrophysiological and behavioral responses. Further field testing with behaviorally-active compounds is needed for the development of a new QFF female lure.


Assuntos
Odorantes/análise , Tephritidae/fisiologia , Compostos Orgânicos Voláteis/análise , Animais , Antenas de Artrópodes/fisiologia , Comportamento Animal/efeitos dos fármacos , Fenômenos Eletrofisiológicos/efeitos dos fármacos , Feminino , Frutas/química , Frutas/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Psidium/química , Psidium/metabolismo , Compostos Orgânicos Voláteis/química , Compostos Orgânicos Voláteis/farmacologia
18.
Molecules ; 25(3)2020 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-32050419

RESUMO

Root-knot nematode diseases cause severe yield and economic losses each year in global agricultural production. Virgibacillus dokdonensis MCCC 1A00493, a deep-sea bacterium, shows a significant nematicidal activity against Meloidogyne incognita in vitro. However, information about the active substances of V. dokdonensis MCCC 1A00493 is limited. In this study, volatile organic compounds (VOCs) from V. dokdonensis MCCC 1A00493 were isolated and analyzed through solid-phase microextraction and gas chromatography-mass spectrometry. Four VOCs, namely, acetaldehyde, dimethyl disulfide, ethylbenzene, and 2-butanone, were identified, and their nematicidal activities were evaluated. The four VOCs had a variety of active modes on M. incognita juveniles. Acetaldehyde had direct contact killing, fumigation, and attraction activities; dimethyl disulfide had direct contact killing and attraction activities; ethylbenzene had an attraction activity; and 2-butanone had a repellent activity. Only acetaldehyde had a fumigant activity to inhibit egg hatching. Combining this fumigant activity against eggs and juveniles could be an effective strategy to control the different developmental stages of M. incognita. The combination of direct contact and attraction activities could also establish trapping and killing strategies against root-knot nematodes. Considering all nematicidal modes or strategies, we could use V. dokdonensis MCCC 1A00493 to set up an integrated strategy to control root-knot nematodes.


Assuntos
Antinematódeos/isolamento & purificação , Doenças das Plantas/prevenção & controle , Tylenchoidea/efeitos dos fármacos , Virgibacillus/química , Compostos Orgânicos Voláteis/isolamento & purificação , Acetaldeído/isolamento & purificação , Acetaldeído/farmacologia , Animais , Antinematódeos/farmacologia , Organismos Aquáticos , Derivados de Benzeno/isolamento & purificação , Derivados de Benzeno/farmacologia , Butanonas/isolamento & purificação , Butanonas/farmacologia , Quimiotaxia/efeitos dos fármacos , Dissulfetos/isolamento & purificação , Dissulfetos/farmacologia , Cromatografia Gasosa-Espectrometria de Massas , Lycopersicon esculentum/efeitos dos fármacos , Lycopersicon esculentum/parasitologia , Contagem de Ovos de Parasitas , Doenças das Plantas/parasitologia , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/parasitologia , Microextração em Fase Sólida , Tylenchoidea/crescimento & desenvolvimento , Compostos Orgânicos Voláteis/farmacologia
19.
Planta ; 251(2): 48, 2020 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-31932951

RESUMO

MAIN CONCLUSION: Salinity alters VOC profile in emitter sweet basil plants. Airborne signals by emitter plants promote earlier flowering of receivers and increase their reproductive success under salinity. Airborne signals can prime neighboring plants against pathogen and/or herbivore attacks, whilst little is known about the possibility that volatile organic compounds (VOCs) emitted by stressed plants alert neighboring plants against abiotic stressors. Salt stress (50 mM NaCl) was imposed on Ocimum basilicum L. plants (emitters, namely NaCl), and a putative alerting-priming interaction was tested on neighboring basil plants (receivers, namely NaCl-S). Compared with the receivers, the NaCl plants exhibited reduced biomass, lower photosynthesis, and changes in the VOC profile, which are common early responses of plants to salinity. In contrast, NaCl-S plants had physiological parameters similar to those of nonsalted plants (C), but exhibited a different VOC fingerprint, which overlapped, for most compounds, with that of emitters. NaCl-S plants exposed later to NaCl treatment (namely NaCl-S + NaCl) exhibited changes in the VOC profile, earlier plant senescence, earlier flowering, and higher seed yield than C + NaCl plants. This experiment offers the evidence that (1) NaCl-triggered VOCs promote metabolic changes in NaCl-S plants, which, finally, increase reproductive success and (2) the differences in VOC profiles observed between emitters and receivers subjected to salinity raise the question whether the receivers are able to "propagate" the warning signal triggered by VOCs in neighboring companions.


Assuntos
Ocimum basilicum/fisiologia , Reprodução/efeitos dos fármacos , Salinidade , Estresse Salino/efeitos dos fármacos , Compostos Orgânicos Voláteis/farmacologia , Biomassa , Carbono/metabolismo , Clorofila/metabolismo , Etilenos/biossíntese , Flavonoides/metabolismo , Fluorescência , Gases/metabolismo , Metabolômica , Nitrogênio/metabolismo , Ocimum basilicum/efeitos dos fármacos , Fenótipo , Fotossíntese/efeitos dos fármacos , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Brotos de Planta/efeitos dos fármacos , Brotos de Planta/crescimento & desenvolvimento , Estômatos de Plantas/efeitos dos fármacos , Estômatos de Plantas/fisiologia , Análise de Componente Principal
20.
J Chem Ecol ; 46(3): 288-298, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31953705

RESUMO

Cowpea, Vigna unguiculata L. Walp. (Fabaceae), is one of the most important food legumes grown on the African continent, as it provides an affordable source of dietary protein. Yields of cowpea are significantly reduced through damage by legume pod-borer, Maruca vitrata (Lepidoptera: Crambidae), caterpillars to flowers, tender leaves and pods. Semiochemical-based strategies are considered as environmentally benign and affordable for pest management, particularly on smallholder farms. In this study, we investigated the importance of cowpea flower volatiles as host location cues for egg-laying M. vitrata, and herbivore-induced plant volatiles (HIPVs) as M. vitrata repellents and natural enemy (Apanteles taragamae and Phanerotoma syleptae parasitoid) attractants. In oviposition choice assays, M. vitrata laid more eggs on flowering cowpea plants than non-flowering plants. Coupled gas chromatography-electrophysiology (GC-EAG) analysis using the antennae of female M. vitrata and an extract of flower volatiles collected by dynamic headspace collection revealed the presence of five EAG-active components that were identified by coupled GC-mass spectrometry (GC-MS) analysis as benzaldehyde, benzyl alcohol, acetophenone, a vinylbenzaldehyde isomer and (E)-cinnamaldehyde. A synthetic blend of the identified compounds, prepared using 3-vinylbenzaldehyde, induced M. vitrata to lay as many eggs on non-flowering cowpea as on flowering plants. The moths also preferred laying eggs on intact plants compared to M. vitrata-infested plants. As the emission of EAG-active floral compounds was determined to be lower in the headspace of infested cowpea flowers, the role of HIPVs emitted by M. vitrata-damaged leaves was also investigated. Of the compounds induced by larval damage, (E)-DMNT, indole, n-hexyl acetate, 1-octen-3-ol and linalool were shown by GC-EAG to possess electrophysiological activity. A synthetic blend of the EAG-active compounds, using racemic 1-octen-3-ol and linalool, significantly reduced egg numbers on flowering cowpea. Larval and egg parasitoids, i.e. A. taragamae and Ph. syleptae, respectively, of M. vitrata both preferred the Y-tube olfactometer arm treated with synthetic (E)-DMNT, whereas preference for racemic linalool and (E)-nerolidol was dose-dependent in A. taragamae. Our results provide the platform for the development of future semiochemical-based pest management strategies against M. vitrata on smallholder farms in West Africa.


Assuntos
Controle de Insetos , Mariposas , Controle Biológico de Vetores , Feromônios/farmacologia , Vigna/química , Compostos Orgânicos Voláteis/farmacologia , Animais , Flores/química , Oviposição
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