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1.
Life Sci ; 274: 119325, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33713665

RESUMO

AIMS: The emergence of antibiotic tolerance was a tricky problem in the treatment of chronic Pseudomonas aeruginosa-infected cystic fibrosis and burn victims. The quorum sensing (QS) inhibitor may serve as a new tactic for the bacterial resistance by inhibiting the biofilm formation and the production of virulence factors. This study explored the potential of luteolin as a QS inhibitor against P. aeruginosa and the molecular mechanism involved. MAIN METHODS: Crystal violet staining, CLSM observation, and SEM analysis were carried out to assess the effect of luteolin on biofilm formation. The motility assays and the production of virulence factors were determined to evaluate the QS-inhibitory activity of luteolin. Acyl-homoserine lactone, RT-PCR, and molecular docking assays were conducted to explain its anti-QS mechanisms. KEY FINDINGS: The biofilm formation, the production of virulence factors, and the motility of P. aeruginosa could be efficiently inhibited by luteolin. Luteolin could also attenuate the accumulation of the QS-signaling molecules N-(3-oxododecanoyl)-L-homoserine lactone (OdDHL) and N-butanoyl-L-homoserine lactone (BHL) (P < 0.01) and downregulate the transcription levels of QS genes (lasR, lasI, rhlR, and rhlI) (P < 0.01). Molecular docking analysis indicated that luteolin had a greater docking affinity with LasR regulator protein compared with OdDHL. SIGNIFICANCE: This study is important as it reports the molecular mechanisms involved in the anti-biofilm formation activity of luteolin against P. aeruginosa. This study also indicated that luteolin could be helpful when used for the treatment of clinical drug-resistant infections of P. aeruginosa.


Assuntos
Proteínas de Bactérias/metabolismo , Biofilmes/efeitos dos fármacos , Regulação Bacteriana da Expressão Gênica , Luteolina/farmacologia , Infecções por Pseudomonas/tratamento farmacológico , Pseudomonas aeruginosa/efeitos dos fármacos , Percepção de Quorum/efeitos dos fármacos , Transativadores/metabolismo , 4-Butirolactona/análogos & derivados , 4-Butirolactona/antagonistas & inibidores , Biofilmes/crescimento & desenvolvimento , Homosserina/análogos & derivados , Homosserina/antagonistas & inibidores , Humanos , Simulação de Acoplamento Molecular , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/isolamento & purificação , Fatores de Virulência
2.
Pest Manag Sci ; 77(5): 2584-2590, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33491844

RESUMO

BACKGROUND: Chemical control is the most used and effective method to control Diaphorina citri, the vector of the phloem-limited bacteria associated with citrus huanglongbing (HLB) disease. The objectives of this study were to determine the effectiveness of flupyradifurone applied via dripping irrigation systems on D. citri. Bioassays were conducted using leaves harvested on various dates post treatment, and insecticide residue in leaf tissue was quantified. RESULTS: The drip application of flupyradifurone on citrus trees provided high-level and long-term control against D. citri adult, and the median lethal concentration (LC50 ) for ingestion of flupyradifurone in D. citri was 22.22 mg kg-1 (fresh leaf). Flupyradifurone residue was detected in leaf tissue within 3 days after treatment. The measured level of flupyradifurone peaked on day 40 day after application, and then showed a steady decline in subsequent days for all three applied dosages. The amounts of flupyradifurone in upper, middle, and lower leaves were similar, and trends in the change in concentration of flupyradifurone were consistent. CONCLUSIONS: The results demonstrate that flupyradifurone can be a valuable new tool for D. citri management programs, and drip-applied flupyradifurone provides an extended period of control efficacy. This paper could provide a reference to reduce the dependence on foliar-applied insecticides, with associated benefits for non-target exposure to workers and pollinators. © 2021 Society of Chemical Industry.


Assuntos
Citrus , Hemípteros , Inseticidas , 4-Butirolactona/análogos & derivados , Animais , Humanos , Piridinas
3.
Pest Manag Sci ; 77(5): 2395-2402, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33415823

RESUMO

BACKGROUND: Spirodiclofen is a spirocyclic tetronic acid-type acaricidal agent. Nowadays, serious pests resistance to spirodiclofen and cross-resistance to other acaricides has appeared. To overcome pests resistance and discover new potential agrochemicals, a series of ether derivatives were prepared based on spirodiclofen as a lead compound. Their pesticidal activities were investigated against three typically agricultural pests, Mythimna separata Walker, Aphis citricola Van der Goot and Tetranychus cinnabarinus Boisduval. RESULTS: Four steric structures of compounds 5e, 5f, 5i and 5j were determined by single-crystal X-ray diffraction. Against T. cinnabarinus, compounds 5b, 5f and 5l exhibited potent acaricidal activity, and their good control effects in the glasshouse were observed when compared with spirodiclofen, especially the control efficiency of compound 5b was comparable to that of spirodiclofen; against M. separata, compound 5j showed > 1.8-fold potent insecticidal activity of spirodiclofen; against A. citricola, compounds 5d and 5j displayed > 2.0-fold potent aphicidal activity of spirodiclofen. The relationships between their structures and agricultural activities were also discussed. CONCLUSION: Compounds 5b and 5d could be further studied as acaricidal and aphicidal agents, respectively; compound 5j can be considered as a lead compound for the insecticidal and aphicidal activities. This will pave the way for future application of these derivatives as pesticide substitutes for spirodiclofen. © 2021 Society of Chemical Industry.


Assuntos
Acaricidas , Inseticidas , Praguicidas , Tetranychidae , 4-Butirolactona/análogos & derivados , Acaricidas/farmacologia , Animais , Éter , Inseticidas/farmacologia , Estrutura Molecular , Praguicidas/farmacologia , Compostos de Espiro , Relação Estrutura-Atividade
4.
Phytomedicine ; 82: 153448, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33421904

RESUMO

BACKGROUND: Acute myeloid leukemia (AML) is a devastating hematologic malignancy with a high mortality. The nuclear receptors Nur77 and NOR-1 are commonly downregulated in human AML blasts and have emerged as key therapeutic targets for AML. METHODS: This study aimed to identify Z-ligustilide (Z-LIG), the main phthalide of Rhizoma Chuanxiong, as a potential agent that can selectively target AML. The anti-AML activity of Z-LIG was evaluated in vitro and in vivo, and the effect and underlying mechanisms of Z-LIG on the restoration of Nur77 and NOR-1 was determined. Moreover, the role of Nur77 and NOR-1 in the regulation of Z-LIG-induced apoptosis and differentiation of AML cells was explored. RESULTS: Z-LIG preferentially inhibited the viability of human AML cells, as well as suppressed the proliferation and colony formation ability. Notably, a concentration-dependent dual effect of Z-LIG was observed in AML cells: inducing apoptosis at relatively high concentrations (25 µM to 100 µM) and promoting differentiation at relatively low concentrations (10 µM and 25 µM). Importantly, Z-LIG restored Nur77 and NOR-1 expression in AML cells by increasing Ace-H3 (lys9/14) enrichment in their promoters. Meanwhile, Z-LIG enhanced the recruitment of p300 and reduced the recruitment of HDAC1, HDAC4/5/7, and MTA1 in the Nur77 promoter and enhanced the recruitment of p-CREB and reduced HDAC1 and HDAC3 in the NOR-1 promoter. Furthermore, Z-LIG-induced apoptosis was shown to be correlated with the mitochondria localization of Nur77/NOR-1 and subsequent Bcl-2 conformational change, converting Bcl-2 from a cyto-protective phenotype into a cyto-destructive phenotype. Z-LIG-promoted differentiation was found to be related to Nur77/NOR-1-mediated myeloid differentiation-associated transcription factors Jun B, c-Jun, and C/EBPß. Finally, silencing of Nur77 and NOR-1 attenuated anti-AML activity of Z-LIG in NOD/SCID mice. CONCLUSIONS: Our study suggests that Z-LIG may serve as a novel bifunctional agent for AML by restoring Nur77/NOR-1-mediated apoptosis and differentiation.


Assuntos
4-Butirolactona/análogos & derivados , Apoptose/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Leucemia Mieloide Aguda/patologia , Proteínas de Membrana Transportadoras/metabolismo , Membro 1 do Grupo A da Subfamília 4 de Receptores Nucleares/metabolismo , 4-Butirolactona/farmacologia , Animais , Humanos , Leucemia Mieloide Aguda/metabolismo , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID
5.
Pestic Biochem Physiol ; 171: 104744, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33357566

RESUMO

The sweetpotato whitefly Bemisia tabaci is a polyphagous crop pest distributed worldwide and frequent exposure to many different defensive secondary metabolites in its host plants. To counteract these defensive plant secondary metabolites, B. tabaci elevate their production of detoxification enzymes, including cytochrome P450 monooxygenases. Besides their tolerance to phytotoxin, B. tabaci have quickly developed resistance to various insecticides in the field. However, the relationship between host plant secondary metabolites and insecticide resistance in B. tabaci is not fully understood. In this study, the influence of plant flavonoid ingestion on B. tabaci tolerance to thiamethoxam and flupyradifurone insecticides and its possible mechanism were examined. Eight plant flavonoids were screened to evaluate their effects on B. tabaci adult sensitivity to thiamethoxam and flupyradifurone. Of which rutin, quercetin, kaempferol, myricetin and catechin significantly reduced adult sensitivity to thiamethoxam and flupyradifurone. Application of cytochrome P450 inhibitor piperonyl butoxide significantly increased the mortality of B. tabaci adults treated with thiamethoxam and flupyradifurone. Moreover, flavonoid ingestion predominantly enhanced the activity of cytochrome P450 enzyme in B. tabaci adults. Meanwhile, the expression level of three cytochrome P450 genes, CYP6CM1, CYP6CX4 and CYP4C64 were induced by the flavonoids in B. tabaci adults. In conclusion, plant flavonoids enhanced the tolerance to thiamethoxam and flupyradifurone in B. tabaci and cytochrome P450s may contribute the flavonoid adaptation. The reduced sensitivity of thiamethoxam and flupyradifurone in flavonoid-fed B. tabaci adults suggested that previous exposure to the host plant-derived flavonoids is likely to compromise the efficacy of insecticides.


Assuntos
Hemípteros , Inseticidas , 4-Butirolactona/análogos & derivados , Animais , Flavonoides/farmacologia , Resistência a Inseticidas/genética , Inseticidas/farmacologia , Piridinas , Tiametoxam
6.
Ecotoxicol Environ Saf ; 207: 111268, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32916533

RESUMO

Foraging is essential for honey bee colony fitness and is enhanced by the waggle dance, a recruitment behavior in which bees can communicate food location and quality. We tested if the consumption of nectar (sucrose solution) with a field-realistic concentration of 4 ppm flupyradifurone (FPF) could alter foraging behavior and recruitment dancing in Apis mellifera. Foragers were repelled by FPF. They visited the FPF feeder less often and spent less time imbibing sucrose solution (2.5 M, 65% w/w) with FPF. As a result, bees feeding on the FPF treatment consumed 16% less nectar. However, FPF did not affect dancing: there were no effects on unloading wait time, the number of dance bouts per nest visit, or the number of dance circuits performed per dance bout. FPF could therefore deter bees from foraging on contaminated nectar. However, the willingness of bees to recruit nestmates for nectar with FPF is concerning. Recruitment can rapidly amplify the number of foragers and could overcome the decrease in consumption of FPF-contaminated nectar, resulting in a net inflow of pesticide to the colony. FPF also significantly altered the expression of 116 genes, some of which may be relevant for the olfactory learning deficits induced by FPF and the toxicity of FPF.


Assuntos
4-Butirolactona/análogos & derivados , Abelhas/fisiologia , Inseticidas/toxicidade , Néctar de Plantas , Piridinas/toxicidade , 4-Butirolactona/toxicidade , Animais , Abelhas/efeitos dos fármacos , Comportamento Alimentar , Alimentos , Sacarose
7.
PLoS One ; 15(12): e0243750, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33315941

RESUMO

The genus Angelica encompasses 80 species worldwide. Among them, only Angelica sinensis is widely used in China and Japan. To explore the quality and geographical distribution of A. sinensis, we collected 1,530 plants from Gansu Province and analyzed them for their contents of chlorogenic acid (CA), ferulic acid (FA), senkyunolide I(SI), senkyunolide A(SA), senkyunolide H (SH), coniferyl ferulate (CF), ligustilide (LI), and butenyl phthalide (BP) using UPLC. We also assessed the relationship between the ecological environment and quality of A. sinensis through maximum entropy modeling and a geographical information system. The habitat suitability distribution demonstrated that the most influential ecological factors for the growth of A. sinensis were altitude, precipitation during March, May, and December, precipitation during the wettest month, and the soil pH. The most suitable areas for cultivation are concentrated to the south of Gansu Province, including Linxia Hui Autonomous Prefecture, Dingxi City, Tianshui City, south of Wuwei City, east of Gannan Tibetan Autonomous Prefecture, north of Longnan City, and northwest of Pingliang City. The quality suitability regionalization analysis divulged that the most influential ecological factors for the index components of A. sinensis were the altitude, sunshine, rainfall, temperature, and soil pH. The highest quality A. sinensis grow in Dingxi City, Tangchang, Lixian, and Wen counties in Longnan City, Wushan County in Tianshui City, Lintan, Zhouqu, and Zhuoni counties in Gannan Tibetan Autonomous Prefecture, Kangle and Linxia counties in Linxia Hui Autonomous Prefecture. The experiment yielded highly accurate results (accuracy of 0.955), suggesting that the results were consistent with the actual distribution of A. sinensis in Gansu. The inferences of this research will naturally draw the attention of the authorities in the fields of natural resources and agriculture departments and provide a scientific basis for the rational selection of A. sinensis cultivation areas.


Assuntos
Angelica sinensis/química , Extratos Vegetais/química , 4-Butirolactona/análogos & derivados , 4-Butirolactona/análise , Benzofuranos/análise , China , Ácido Clorogênico/análise , Cromatografia Líquida de Alta Pressão , Ácidos Cumáricos/análise
8.
Exp Appl Acarol ; 82(3): 319-333, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33068164

RESUMO

Salicylic acid (SA) is a signaling molecule that can induce plant resistance to certain herbivores. Although the role of jasmonic acid in mediating mite-tomato plant interactions has been well studied, the role of salicylic acid has not. This study examined how the application of exogenous SA, via its effects on tomato plant physiology, alters the activity of mite digestive enzymes, mite energy reserves, and mite susceptibility to spirodiclofen. Enzymatic activity-including superoxide dismutase, ascorbate peroxidase, guaiacol peroxidase, polyphenol oxidase, and phenylalanine ammonia-lyase-along with contents of total phenolic, hydrogen peroxide, and total chlorophyll significantly increased in plants 24 h after treatment with 2 mM of SA. In contrast, catalase activity significantly decreased in treated plants, and malondialdehyde content was unaffected. Mites fed on tomato plants treated with SA had significantly lower glutathione S-transferase, esterase, α-amylase, and aminopeptidase activities than those fed on control plants. Energy reserve analyses demonstrated a significant decrease in contents of lipid, protein, and glycogen in mites fed on SA-treated plants, whereas carbohydrate content significantly increased. The LC50 of spirodiclofen was decreased 1.8-fold for Tetranychus urticae fed on SA-treated tomato plants compared to controls. Treatment of adult mites with 2 mM SA on leaf discs did not cause any direct mortality after 24 h. Finally, a greenhouse bioassay confirmed that spider mite mortality following exposure to spirodiclofen was significantly higher on SA plants than on control plants. Mortality of mites exposed to half of the recommended rate of spirodiclofen was similar to those exposed to the recommended rate when they were held on treated plants. These results have valuable implications for T. urticae management programs in tomato production.


Assuntos
4-Butirolactona/análogos & derivados , Acaricidas , Lycopersicon esculentum/fisiologia , Ácido Salicílico/farmacologia , Compostos de Espiro , Tetranychidae , Animais
9.
Zhongguo Zhong Yao Za Zhi ; 45(16): 3931-3937, 2020 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-32893591

RESUMO

This study aimed to investigate the effect and mechanism of ligustilide, the main active ingredient in Ligusticum wallichii, on mitochondria fission after PC12 cell injury induced by oxygen and glucose deprivation/reperfusion(OGD/R). In the experiment, an OGD/R model was established in vitro, and PC12 cells were pre-treated with ligustilide for 3 h, and then the cell viability was detected by CCK-8 method. The effect of different concentrations of ligustilide on the morphology of PC12 cells after OGD/R injury was observed under an inverted microscope. Transmission electron microscopy was used to observe the mitochondrial fission of PC12 cells after OGD/R injury. DCFH-DA immunofluorescence staining method was used to detect intracellular reactive oxygen species(ROS) changes. Changes in mitochondria membrane potential(MMP) were detected by flow cytometry. Hochest 33258 was used to observe the apoptosis of PC12 cells. Western blot was used to detect changes in cytochrome C(Cyt C) content in mitochondria and cytoplasm, and mitochondrial fission-related proteins Drp 1 and Fis 1. All results showed that compared with the model group, ligustilide significantly increased the survival rate of PC12 cells and the number of cells. Further experiments showed that ligustilide inhibited the release of ROS and decline of mitochondrial membrane potential in PC12 cells after OGD/R injury. Moreover, ligustilide reduced the release of Cyt C and promoted the expressions of Drp1 and Fis1 in mitochondrial fission proteins. Verification experiments showed that mitochondrial fission inhibitor mdivi-1 decreased cell survival rate and inhibited fission. The results indicated that ligustilide exerted neuro-protective effects by promoting mitochondrial fission and reducing cell damage. It preliminary proves that the mechanism of ligustilide on ischemic brain injury may be related to the promotion of mitochondrial fission and the maintenance of cell homeostasis.


Assuntos
Glucose , Traumatismo por Reperfusão , 4-Butirolactona/análogos & derivados , Animais , Apoptose , Sobrevivência Celular , Mitocôndrias , Oxigênio , Células PC12 , Ratos , Espécies Reativas de Oxigênio
10.
Proc Biol Sci ; 287(1935): 20201265, 2020 09 30.
Artigo em Inglês | MEDLINE | ID: mdl-32993471

RESUMO

Systemic insecticides, such as neonicotinoids, are a major contributor towards beneficial insect declines. This has led to bans and restrictions on neonicotinoid use globally, most noticeably in the European Union, where four commonly used neonicotinoids (imidacloprid, thiamethoxam, clothianidin and thiacloprid) are banned from outside agricultural use. While this might seem like a victory for conservation, restrictions on neonicotinoid use will only benefit insect populations if newly emerging insecticides do not have similar negative impacts on beneficial insects. Flupyradifurone and sulfoxaflor are two novel insecticides that have been registered for use globally, including within the European Union. These novel insecticides differ in their chemical class, but share the same mode of action as neonicotinoids, raising the question as to whether they have similar sub-lethal impacts on beneficial insects. Here, we conducted a systematic literature search of the potential sub-lethal impacts of these novel insecticides on beneficial insects, quantifying these effects with a meta-analysis. We demonstrate that both flupyradifurone and sulfoxaflor have significant sub-lethal impacts on beneficial insects at field-realistic levels of exposure. These results confirm that bans on neonicotinoid use will only protect beneficial insects if paired with significant changes to the agrochemical regulatory process. A failure to modify the regulatory process will result in a continued decline of beneficial insects and the ecosystem services on which global food production relies.


Assuntos
Insetos , Inseticidas , 4-Butirolactona/análogos & derivados , Animais , Ecossistema , Guanidinas , Neonicotinoides , Nitrocompostos , Piridinas , Compostos de Enxofre , Tiametoxam , Tiazinas , Tiazóis
11.
Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi ; 36(9): 776-781, 2020 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-32967760

RESUMO

Objective To explore the regulatory effect of quorum sensing molecule N-3-oxodecanoyl-L-homoserine lactone (3-oxo-C10-HSL) on lipopolysaccharide (LPS)-induced inflammation in RAW264.7 macrophages. Methods RAW264.7 macrophages were divided into experimental group, control group and blank group. The experimental group was treated with different concentrations of 3-oxo-C10-HSL and LPS; the control group was treated with DMSO and LPS; and the blank group was treated with DMSO and PBS. Cells and supernatants were collected after 12 hours of stimulation. The mRNA expression of interleukin-6 (IL-6), interleukin-1ß (IL-1ß), tumor necrosis factor-α (TNF-α) and monocyte chemoattractant protein-1 (MCP-1) were detected by real-time quantitative PCR, and the protein levels of IL-6 and TNF-α in supernatant were detected by ELSIA. Further, 25 µmol/L 3-oxo-C10-HSL and 100 ng/mL LPS were used to stimulate the cells for 15, 30 and 60 minutes, and the phosphorylation of nuclear factor κBp65 (NF-κBp65) was detected by Western blot analysis. Results The 3-oxo-C10-HSL could decrease the mRNA levels of IL-6, IL-1ß, TNF-α, MCP-1 and the protein levels of IL-6 and TNF-α in LPS-treated RAW264.7 macrophages in a dose-dependent manner. In addition, 3-oxo-C10-HSL could inhibit the phosphorylation of NF-κBp65 induced by LPS. Conclusion 3-oxo-C10-HSL can alleviate LPS-induced inflammatory responses in RAW264.7 macrophages by inhibiting activation of NF-κB signaling pathway.


Assuntos
Percepção de Quorum , 4-Butirolactona/análogos & derivados , Lipopolissacarídeos , Macrófagos , NF-kappa B , Fator de Necrose Tumoral alfa/genética
12.
PLoS Genet ; 16(8): e1008992, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32797092

RESUMO

Bacterial virulence factors facilitate host colonization and set the stage for the evolution of parasitic and mutualistic interactions. The Sodalis-allied clade of bacteria exhibit striking diversity in the range of both plant and animal feeding insects they inhabit, suggesting the appropriation of universal molecular mechanisms that facilitate establishment. Here, we report on the infection of the tsetse fly by free-living Sodalis praecaptivus, a close relative of many Sodalis-allied symbionts. Key genes involved in quorum sensing, including the homoserine lactone synthase (ypeI) and response regulators (yenR and ypeR) are integral for the benign colonization of S. praecaptivus. Mutants lacking ypeI, yenR and ypeR compromised tsetse survival as a consequence of their inability to repress virulence. Genes under quorum sensing, including homologs of the binary insecticidal toxin PirAB and a putative symbiosis-promoting factor CpmAJ, demonstrated negative and positive impacts, respectively, on tsetse survival. Taken together with results obtained from experiments involving weevils, this work shows that quorum sensing virulence suppression plays an integral role in facilitating the establishment of Sodalis-allied symbionts in diverse insect hosts. This knowledge contributes to the understanding of the early evolutionary steps involved in the formation of insect-bacterial symbiosis. Further, despite having no established history of interaction with tsetse, S. praecaptivus can infect reproductive tissues, enabling vertical transmission through adenotrophic viviparity within a single host generation. This creates an option for the use of S. praecaptivus in the biocontrol of insect disease vectors via paratransgenesis.


Assuntos
Percepção de Quorum/genética , Moscas Tsé-Tsé/genética , Fatores de Virulência/genética , 4-Butirolactona/análogos & derivados , 4-Butirolactona/biossíntese , 4-Butirolactona/genética , Animais , Enterobacteriaceae/genética , Enterobacteriaceae/patogenicidade , Humanos , Insetos Vetores/genética , Insetos Vetores/microbiologia , Insetos/genética , Simbiose/genética , Moscas Tsé-Tsé/microbiologia
13.
Chemosphere ; 261: 127760, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32731029

RESUMO

Predatory mites belonging to family Phytoseiidae (Acari: Mesostigmata) have long been considered as the most promising candidates for biological control of some economically important plant feeding mites and insects. Among them, Euseius scutalis (Athias-Henriot) is one of the most abundant predators and can be considered as an important component for integrated pest management (IPM) programs in Mediterranean citrus orchards. Evaluation of non-target and toxic effects of pesticides is crucial to measure their threats to E. scutalis. In this study, the effects of some selected acaricides (abamectin, etoxazole, spirodiclofen, spirotetramat and pyridaben), that were widely used in citrus orchards, on eggs, larvae, and adult females of E. scutalis were determined under laboratory conditions. In order to observe some possible results at "worst-case scenario", the test units were sprayed at maximum recommended doses. According to the results, abamectin and pyridaben respectively caused 18.00% and 33.50% mortality on eggs, 57.33% and 65.33% on larvae, 23.33% and 44.00% on adult females. While etoxazole was only toxic to the larvae with mortality rates reaching 55.33%, spirodiclofen and spirotetramat were harmless to all developmental stages of the predatory mite. In addition, abamectin, etoxazole and pyridaben caused a significant reduction in the egg production of E. scutalis when compared to the control. Accordingly, spirodiclofen and spirotetramat may be compatible with E. scutalis in IPM programs where it is implemented as a predator. However, further semi-field and/or field experiments are essential in order to draw a final conclusion on compatibility of the other three acaricides.


Assuntos
Acaricidas/toxicidade , Ácaros/efeitos dos fármacos , 4-Butirolactona/análogos & derivados , Animais , Compostos Aza , Citrus/efeitos dos fármacos , Feminino , Ivermectina/análogos & derivados , Larva/efeitos dos fármacos , Controle de Pragas , Praguicidas/farmacologia , Piridazinas , Compostos de Espiro
14.
Int J Food Microbiol ; 331: 108732, 2020 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-32521374

RESUMO

The present study aimed to evaluate the anti-quorum sensing (anti-QS) and anti-proteolytic potentials of tarragon essential oil (TEO) and its major compounds against food-associated Pseudomonas spp. The activities were verified by in vitro, in silico and in situ approaches. In this work, methyl eugenol (ME)- and ß-phellandrene (ß-PH)-rich TEO was investigated. TEO at subMIC increased the percentage of saturated fatty acids in the bacterial membranes (from 7 to 22%) and exhibited anti-quorum sensing via decreasing the efficiency of QS autoinducer synthesis [3-oxo-C12-HSL (from 2.028 µg/mL to

Assuntos
Artemisia/química , Óleos Voláteis/farmacologia , Proteólise/efeitos dos fármacos , Pseudomonas/efeitos dos fármacos , Percepção de Quorum/efeitos dos fármacos , 4-Butirolactona/análogos & derivados , 4-Butirolactona/isolamento & purificação , 4-Butirolactona/farmacologia , Animais , Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Simulação por Computador , Peixes/microbiologia , Homosserina/análogos & derivados , Homosserina/isolamento & purificação , Homosserina/farmacologia , Óleos Voláteis/química , Óleos Voláteis/isolamento & purificação , Pseudomonas/isolamento & purificação
15.
Sci Total Environ ; 737: 139386, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32563110

RESUMO

To examine the spatial, and temporal variation and potential sources of pesticide concentrations, primarily neonicotinoid insecticides, in hummingbirds in western Canada, we sampled their cloacal fluid from sites in British Columbia and Saskatchewan, Canada in 2017-2018. At a sub-sample of those sites, we also measured pesticides in honey bee (Apis mellifera) nectar, water, and sediment. We collected cloacal fluid from 5 species of hummingbirds (n = 26 sites) in British Columbia (BC) and Saskatchewan, Canada, and nectar from honey bee hives (n = 4 sites), water and sediment (n = 18 sites) in the Fraser Valley, BC. Among those, multiple types of samples were collected at 6 sites. We report the first measurement of flupyradifurone, a relatively new butenolide insecticide, in wildlife which was detected at 4.58 ng/mL in hummingbird cloacal fluid and 2.18 ng/g in honey bee nectar. We also detected three other neonicotinoids (imidacloprid, clothianidin, acetamiprid) and one metabolite desnitro-imidacloprid, and MGK264, a pesticide synergist, in our samples. Among 49 samples of cloacal fluid from rufous (Selasphorus rufus), Anna's (Calypte anna), calliope (Selasphorus calliope) black-chinned (Archilocus alexandri) and ruby-throated hummingbirds (Archilocus colubris), 26.5% (n = 13) contained neonicotinoids. Maximum pesticide concentrations in hummingbirds, water and sediment were found in samples collected in the Fraser Valley, BC within 0.5 km of conventionally sprayed blueberry fields (CSBF) but highest levels in honey bee nectar were detected at a site 1.5 km from a CSBF. Imidacloprid in honey bee nectar at one site exceeded concentrations (>1 ng/g) that can sublethally affect worker bee foraging efficiency. In water, imidacloprid concentrations at another site exceeded Canadian guidelines (230 ng/mL) for the protection of aquatic invertebrates.


Assuntos
Inseticidas/análise , Nitrocompostos , 4-Butirolactona/análogos & derivados , Animais , Abelhas , Colúmbia Britânica , Insetos , Neonicotinoides , Saskatchewan
16.
PLoS One ; 15(5): e0233033, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32437365

RESUMO

Pesticide exposures can have detrimental impacts on bee pollinators, ranging from immediate mortality to sub-lethal impacts. Flupyradifurone is the active ingredient in Sivanto™ and sulfoxaflor is the active ingredient in Transform®. They are both relatively new insecticides developed with an intent to reduce negative effects on bees, when applied to bee-attractive crops. With the growing concern regarding pollinator health and pollinator declines, it is important to have a better understanding of any potential negative impacts, especially sub-lethal, of these pesticides on bees. This study reports novel findings regarding physiological stress experienced by bees exposed to field application rates of these two insecticides via a Potter Tower sprayer. Two contact exposure experiments were conducted-a shorter 6-hour study and a longer 10-day study. Honey bee mortality, sugar syrup and water consumption, and physiological responses (oxidative stress and apoptotic protein assays) were assessed in bees exposed to Sivanto™ and Transform®, and compared to bees in control group. For the longer, 10-day contact exposure experiment, only the Sivanto™ group was compared to the control group, as high mortality recorded in the sulfoxaflor treatment group during the shorter contact exposure experiment, made the latter group unfeasible to test in the longer 10-days experiment. In both the studies, sugar syrup and water consumptions were significantly different between treatment groups and controls. The highest mortality was observed in Transform® exposed bees, followed by the Sivanto™ exposed bees. Estimates of reactive oxygen/nitrogen species indicated significantly elevated oxidative stress in both pesticide treatment groups, when compared to controls. Caspase-3 protein assays, an indicator of onset of apoptosis, was also significantly higher in the pesticide treatment groups. These differences were largely driven by post exposure duration, indicating sub-lethal impacts. Further, our findings also emphasize the need to revisit contact exposure impacts of Sivanto™, given the sub-lethal impacts and mortality observed in our long-term (10-day) contact exposure experiment.


Assuntos
4-Butirolactona/análogos & derivados , Abelhas/efeitos dos fármacos , Praguicidas/efeitos adversos , Piridinas/efeitos adversos , Compostos de Enxofre/efeitos adversos , 4-Butirolactona/efeitos adversos , Animais , Abelhas/metabolismo , Caspase 3/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Proteínas de Insetos/metabolismo , Estresse Oxidativo , Polinização , Fatores de Tempo
17.
Chemosphere ; 255: 126945, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32388260

RESUMO

This study investigated the effects of exogenous N-acyl-homoserine lactone (AHL) signal molecules, N-hexanoyl-l-homoserine lactone (C6-HSL) and N-octanoyl-l-homoserine lactone (C8-HSL), on treatment performance, sludge properties and microbial community structures in activated sludge systems. Results showed that the nitrification and denitrification efficiencies were enhanced with the addition of signal molecules. The particle size, irregularity, and internal mass transfer resistance of activated sludge flocs (ASFs) increased, primarily because dosing AHLs led to a content increase and chemical composition variation of extracellular polymeric substances (EPS) in sludge. Microbial analysis indicated an increase in both the bacterial richness and diversity of the systems. The relative abundances of the key functional groups, including bacteria related to C and N removal and EPS production, varied correspondingly. This study presents an insight into the comprehensive understanding of the effects of AHL-based quorum sensing on activated sludge treatment process.


Assuntos
Acil-Butirolactonas/química , Lactonas/química , 4-Butirolactona/análogos & derivados , Bactérias , Microbiota , Nitrificação , Nutrientes , Percepção de Quorum , Esgotos/química
18.
J Med Microbiol ; 69(6): 906-919, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32459613

RESUMO

Introduction. Indwelling medical devices such as endotracheal tubes (ETTs), urinary catheters, vascular access devices, tracheostomies and feeding tubes are often associated with hospital-acquired infections. Bacterial biofilm formed on the ETTs in intubated patients is a significant risk factor associated with ventilator-associated pneumonia. Pseudomonas aeruginosa is one of the four frequently encountered bacteria responsible for causing pneumonia, and the biofilm formation on ETTs. However, understanding of biofilm formation on ETT and interventions to prevent biofilm remains lagging. The ability to sense and adapt to external cues contributes to their success. Thus, the biofilm formation is likely to be influenced by the two-component systems (TCSs) that are composed of a membrane-associated sensor kinase and an intracellular response regulator.Aim. This study aims to establish an in vitro method to analyse the P. aeruginosa biofilm formation on ETTs, and identify the TCSs that contribute to this process.Methodology. In total, 112 P. aeruginosa PA14 TCS mutants were tested for their ability to form biofilm on ETTs, their effect on quorum sensing (QS) and motility.Results. Out of 112 TCS mutants studied, 56 had altered biofilm biomass on ETTs. Although the biofilm formation on ETTs is QS-dependent, none of the 56 loci controlled quorum signal. Of these, 18 novel TCSs specific to ETT biofilm were identified, namely, AauS, AgtS, ColR, CopS, CprR, NasT, KdpD, ParS, PmrB, PprA, PvrS, RcsC, PA14_11120, PA14_32580, PA14_45880, PA14_49420, PA14_52240, PA14_70790. The set of 56 included the GacS network, TCS proteins involved in fimbriae synthesis, TCS proteins involved in antimicrobial peptide resistance, and surface-sensing. Additionally, several of the TCS-encoding genes involved in biofilm formation on ETTs were found to be linked to flagellum-dependent swimming motility.Conclusions. Our study established an in vitro method for studying P. aeruginosa biofilm formation on the ETT surfaces. We also identified novel ETT-specific TCSs that could serve as targets to prevent biofilm formation on indwelling devices frequently used in clinical settings.


Assuntos
Proteínas de Bactérias/fisiologia , Biofilmes , Intubação Intratraqueal/instrumentação , Pseudomonas aeruginosa/fisiologia , 4-Butirolactona/análogos & derivados , 4-Butirolactona/fisiologia , Contaminação de Equipamentos , Fímbrias Bacterianas/fisiologia , Flagelos/fisiologia , Pneumonia Associada à Ventilação Mecânica/etiologia , Percepção de Quorum
19.
Water Res ; 177: 115756, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32294590

RESUMO

The occurrence and distribution of N-acyl homoserine lactones (AHLs) in membrane bioreactors (MBRs) treating wastewater has garnered much attention as they have been shown to play critical role in biofouling. There is a need to develop a single method capable of analysing AHLs in various wastewater with comparable and reliable performance. A novel and robust method was proposed for trace analysis of 11 AHLs in wastewater treatment systems treating domestic and industrial wastewater. This method utilised solid phase extraction (SPE) to extract AHLs from wastewater followed by liquid-liquid extraction (LLE) to extract AHLs from the SPE eluant, and used N-heptanoyl-dl-homoserine lactone (C7-HSL) as an internal standard. There was no need to prepare matrix-matched calibration curve for accurate quantification of AHLs in the liquid chromatography tandem mass chromatography (LC-MS/MS) analysis. The developed method was validated with six different types of domestic and industrial wastewater with regard to AHLs recoveries and matrix effects. For treated domestic and industrial wastewater, the relative recoveries ranged from 75% to 130% and the matrix effects ranged from 89% to 122%. This method exhibited remarkable improvement compared with single SPE. The results also indicated that inclusion of LLE after SPE could effectively alleviate matrix effects, which may be because of the removal of relatively hydrophilic interferences by using dichloromethane to extract AHLs from the SPE eluant composing of methanol and water. The limits of detection of the AHLs were all below 5 ng/L for the tested wastewater samples. The developed method of SPE-LLE with LC-MS/MS was applied to analyse AHLs in four lab-scale and one pilot-scale wastewater treatment systems. Wide spectrum of AHLs with alkanoyl chains ranging from C4 to C14 were detected with concentrations ranging from 2.7 to 299.2 ng/L. This method is capable of identifying and quantifying trace levels of AHLs in various wastewater treatment systems and can help us better understand the mechanisms of AHL-mediated quroum sensing in various wastewater treatment systems.


Assuntos
Homosserina , Águas Residuárias , 4-Butirolactona/análogos & derivados , Cromatografia Líquida , Extração em Fase Sólida , Espectrometria de Massas em Tandem
20.
Biofouling ; 36(2): 200-209, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-32253933

RESUMO

Biodegradable polymers are promising binders and carriers for natural antifoulants. In the present study, an antifouling (AF) coating was developed by adding a non-toxic AF compound (butenolide) to a bio-based and biodegradable poly(lactic acid)-based polyurethane. Mass loss measurement showed that the polymer degraded in seawater at a rate of 0.013 mg cm-2 day-1. Measurements showed that butenolide was released from the coatings into seawater over a period of at least three months. Both the concentration of butenolide in the coatings and the ambient temperature determined the release rate of butenolide. The results further demonstrate that incorporating rosin into the coatings increase the self-renewal rate of the polymer and facilitated the long-term release of butenolide from the coating. The results show that poly(lactic acid)-based polyurethane is a suitable polymer for butenolide-based AF coatings.


Assuntos
4-Butirolactona/análogos & derivados , Plásticos Biodegradáveis/química , Incrustação Biológica/prevenção & controle , Desinfetantes/química , Poliésteres/química , Poliuretanos/química , 4-Butirolactona/química , Desinfetantes/análise , Água do Mar/química , Propriedades de Superfície
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