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1.
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
2.
PLoS Comput Biol ; 16(7): e1008039, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32649676

RESUMO

Antibiotic production is coordinated in the Streptomyces coelicolor population through the use of diffusible signaling molecules of the γ-butyrolactone (GBL) family. The GBL regulatory system involves a small, and not completely defined two-gene network which governs a potentially bi-stable switch between the "on" and "off" states of antibiotic production. The use of this circuit as a tool for synthetic biology has been hampered by a lack of mechanistic understanding of its functionality. We here present the creation and analysis of a versatile and adaptable ensemble model of the Streptomyces GBL system (detailed information on all model mechanisms and parameters is documented in http://www.systemsbiology.ls.manchester.ac.uk/wiki/index.php/Main_Page). We use the model to explore a range of previously proposed mechanistic hypotheses, including transcriptional interference, antisense RNA interactions between the mRNAs of the two genes, and various alternative regulatory activities. Our results suggest that transcriptional interference alone is not sufficient to explain the system's behavior. Instead, antisense RNA interactions seem to be the system's driving force, combined with an aggressive scbR promoter. The computational model can be used to further challenge and refine our understanding of the system's activity and guide future experimentation.


Assuntos
4-Butirolactona/metabolismo , Streptomyces coelicolor/metabolismo , Antibacterianos , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Simulação por Computador , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Regulação Bacteriana da Expressão Gênica , Redes Reguladoras de Genes , Regiões Promotoras Genéticas , RNA Antissenso/metabolismo , RNA Mensageiro/metabolismo , Streptomyces coelicolor/genética , Biologia Sintética
3.
Bioresour Technol ; 315: 123863, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32717518

RESUMO

Anammox as a novel biological process in natural nitrogen cycle has been introduced into wastewater treatment process. However, the regulation mechanism of anammox metabolism remained to be investigated. In this study, the specific quorum sensing (QS) signaling molecules for mediating anammox were identified in anammox activity tests. Anammox was valve-regulated by the collaboration of QS signaling molecules N-butyryl-homoserine lactone (C14-HSL) and N-(3-oxotetradecanoyl)-homoserine lactone (3-oxo-C14-HSL), and prompted with the C14-HSL/3-oxo-C14-HSL mole ratio above 1.0. Moreover, the ratio of chemical oxygen demand to total nitrogen (C/N) was identified as an effective regulator for the distribution of C14-HSL and 3-oxo-C14-HSL. An engineering method for control anammox through regulating C/N ratio was proposed and demonstrated based on the performance of two microaerobic reactors treating piggery wastewater and anammox activity tests. The discovery should be of great significance to understanding the social behaviors of anammox bacteria in organic wastewater treatment processes.


Assuntos
4-Butirolactona , Percepção de Quorum , Bactérias , Crescimento Quimioautotrófico , Nitrogênio , Transdução de Sinais
4.
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
5.
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
6.
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
7.
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
8.
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
9.
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
10.
Arch Microbiol ; 202(6): 1477-1488, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32193579

RESUMO

Shallow hydrothermal systems are extreme environments. The sediments and fluids emitted from the vents present unusual physical and chemical conditions compared to other marine areas, which promotes unique biodiversity that has been of great interest for biotechnology for some years. In this work, a bioprospective study was carried out to evaluate the capacity of bacteria associated with shallow hydrothermal vents to produce biofilm-inhibiting compounds. Degradation assays of N-acyl homoserine lactone (AHL) autoinducers (C6HSL) involved in the quorum sensing process were carried out on 161 strains of bacteria isolated from three shallow hydrothermal systems located in Baja California Sur (BCS), Mexico. The biosensor Chromobacterium violaceum CV026 was used. Twenty-three strains showed activity, and organic extracts were obtained with ethyl acetate. The potential of the extracts to inhibit the formation of biofilms was tested against two human pathogenic strains (Pseudomonas aeruginosa PAO1 and Aeromonas caviae ScH3), a shrimp pathogen (Vibrio parahaemolyticus M8), and two marine strains identified as producing biofilms on submerged surfaces (Virgibacillus sp C29 and Vibrio alginolyticus C96). The results showed that Vibrio alginolyticus and Brevibacillus thermoruber, as well as some thermotolerant strains (mostly Bacillus), produce compounds that inhibit bacterial biofilms (B. licheniformis, B. paralicheniformis, B. firmus, B. oceanizedimenis, B. aerius and B. sonorensis).


Assuntos
Antibacterianos/metabolismo , Antibiose/fisiologia , Biofilmes/crescimento & desenvolvimento , Chromobacterium/metabolismo , Fontes Hidrotermais/microbiologia , 4-Butirolactona/análogos & derivados , 4-Butirolactona/metabolismo , Aeromonas caviae/efeitos dos fármacos , Bacillus/efeitos dos fármacos , Brevibacillus/efeitos dos fármacos , Chromobacterium/isolamento & purificação , Chromobacterium/fisiologia , México , Pseudomonas aeruginosa/efeitos dos fármacos , Percepção de Quorum/fisiologia , Vibrio alginolyticus/efeitos dos fármacos
11.
J Agric Food Chem ; 68(8): 2516-2527, 2020 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-32050067

RESUMO

In the Gram-negative bacterium Aeromonas hydrophila, N-acyl homoserine lactone (AHL)-mediated quorum sensing (QS) influences pathogenicity, protein secretion, and motility. However, the catalytic mechanism of AHL biosynthesis and the structural basis and substrate specificity for AhyI members remain unclear. In this study, we cloned the ahyI gene from the isolate A. hydrophila HX-3, and the overexpressed AhyI protein was confirmed to produce six types of AHLs by ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) analysis, contrasting with previous reports that AhyI only produces N-butanoyl-l-homoserine lactone (C4-HSL) and N-hexanoyl-l-homoserine lactone (C6-HSL). The results of an in vitro biosynthetic assay showed that purified AhyI can catalyze the formation of C4-HSL using S-adenosyl-l-methionine (SAM) and butyryl-acyl carrier protein (ACP) as substrates and indicated that the fatty acyl substrate used in AhyI-mediated AHL synthesis is derived from acyl-ACP rather than acyl-CoA. The kinetic data of AhyI using butyryl-ACP as an acyl substrate indicated that the catalytic efficiency of the A. hydrophila HX-3 AhyI enzyme is within an order of magnitude compared to other LuxI homologues. In this study, for the first time, the tertiary structural modeling results of AhyI and those of molecular docking and structural and functional analyses showed the importance of several crucial residues, as well as the secondary structure with respect to acylation. A Phe125-Phe152 clamp grasps the terminal methyl group to assist in stabilizing the long acyl chains in a putative binding pocket. The stacking interactions within a strong hydrophobic environment, a hydrogen-bonding network, and a ß bulge presumably stabilize the ACP acyl chain for the attack of the SAM α-amine toward the thioester carbon, offering a relatively reasonable explanation for how AhyI can synthesize AHLs with diverse acyl-chain lengths. Moreover, Trp34 participates in forming the binding pocket for C4-ACP and becomes ordered upon SAM binding, providing a good basis for catalysis. The novel finding that AhyI can produce both short- and long-chain AHLs enhances current knowledge regarding the variety of AHLs produced by this enzyme. These structural data are expected to serve as a molecular rationale for AHL synthesis by AhyI.


Assuntos
Aeromonas hydrophila/enzimologia , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , 4-Butirolactona/análogos & derivados , 4-Butirolactona/metabolismo , Acil-Butirolactonas/química , Acil-Butirolactonas/metabolismo , Aeromonas hydrophila/química , Aeromonas hydrophila/genética , Aeromonas hydrophila/metabolismo , Proteínas de Bactérias/genética , S-Adenosilmetionina/metabolismo , Especificidade por Substrato , Espectrometria de Massas em Tandem
12.
PLoS One ; 15(2): e0227811, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32023266

RESUMO

Anopheles darlingi is the main vector of malaria in Brazil, characterized by a high level of anthropophilia and endophagy. Imidacloprid, thiacloprid, and acetamiprid are the most widespread insecticides of the neonicotinoid group. However, they produce adverse effects on the non-target insects. Flupyradifurone has been marketed as an alternative to non-fluorinated neonicotinoids. Neonicotinoids containing trifluoroacethyl substituent reveal increased insecticidal activity due to higher hydrophobicity and metabolic stability. We synthesized novel neonicotinoid insecticides containing fluorinated acceptor groups and their interactions were estimated with the nicotinic acetylcholine receptor (nAChR) binding site by molecular docking studies, to evaluate their larvicidal activity against A. darlingi, and to assess their outdoor photodegradation behavior. New neonicotinoid analogues were prepared and characterized by NMR and mass-spectrometry. The synthesized molecules were modelled by time-dependent density functional theory and analyzed, their interaction with nAChR was investigated by molecular docking. Their insecticide activity was tested on Anopheles larvae collected in suburban area of Manaus, Brazil. Four new fluorinated neonicotinoid analogs were prepared and tested against 3rd instars larvae of A. darlingi showing high larvicidal activity. Docking studies reveal binding modes of the synthesized compounds and suggest that their insecticidal potency is governed by specific interactions with the receptor binding site and enhanced lipophilicity. 2-Chloro-5-(2-trifluoromethyl-pyrrolidin-1-ylmethyl)pyridine 5 showed fast degradation in water maintaining high larvicidal activity. All obtained substances possessed high larvicidal activity in low concentrations in 48 hours of exposure, compared to commercial flupyradifurone. Such activity is connected to a unique binding pattern of the synthesized compounds to insect's nAChR and to their enhanced bioavailability owing to introduction of fluorinated amino-moieties. Therefore, the compounds in question have a high potential for application as control agents for insects transmitting tropical diseases, and they will be less persistent in the environment.


Assuntos
Anopheles/efeitos dos fármacos , Halogenação , Inseticidas/toxicidade , Simulação de Acoplamento Molecular , Neonicotinoides/toxicidade , 4-Butirolactona/análogos & derivados , 4-Butirolactona/química , 4-Butirolactona/toxicidade , Animais , Inseticidas/química , Larva/efeitos dos fármacos , Neonicotinoides/síntese química , Neonicotinoides/química , Piridinas/química , Piridinas/toxicidade , Espectrofotometria Ultravioleta , Eletricidade Estática
13.
J Oral Biosci ; 62(1): 16-29, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31982630

RESUMO

BACKGROUND: Bacteria exhibit multi-cellular social behavior, such as biofilm formation, virulence generation, bioluminescence, or sporulation, through cell-to-cell communication involving a quorum sensing (QS) system capable of sensing species density. Pseudomonas aeruginosa (P. aeruginosa) is a ubiquitous gram-negative opportunistic pathogen that is frequently isolated from immunocompromised patients. It is particularly detected in patients with severe periodontitis and persistent endodontic infections, forcing a rethink of the role of this opportunistic pathogen in oral lesions. HIGHLIGHT: N-(3-oxododecanoyl)-l-homoserine lactone (OdDHL) is a pivotal QS molecule, which regulates numerous virulence genes in P. aeruginosa and exhibits broad biological modulation effects in mammalian cells. In this review, we highlight the diverse OdDHL-mediated apoptosis and immunomodulatory effects on host cells. The structural properties, signaling pathways, targeted genes and proteins, and intracellular metabolism of OdDHL are also discussed to clarify the interactions between P. aeruginosa and the host. CONCLUSION: The purpose of this review is to identify a valid target for quenching OdDHL, which could potentially eliminate the pathogenic effect of P. aeruginosa.


Assuntos
Homosserina , Percepção de Quorum , 4-Butirolactona/análogos & derivados , Animais , Homosserina/análogos & derivados , Humanos , Lactonas , Pseudomonas aeruginosa
14.
BMC Plant Biol ; 20(1): 38, 2020 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-31992205

RESUMO

BACKGROUD: Many Gram-negative bacteria use N-acyl-homoserine lactones (AHLs) to communicate each other and to coordinate their collective behaviors. Recently, accumulating evidence shows that host plants are able to sense and respond to bacterial AHLs. Once primed, plants are in an altered state that enables plant cells to more quickly and/or strongly respond to subsequent pathogen infection or abiotic stress. RESULTS: In this study, we report that pretreatment with N-3-oxo-octanoyl-homoserine lactone (3OC8-HSL) confers resistance against the pathogenic bacterium Pseudomonas syringae pv. tomato DC3000 (PstDC3000) in Arabidopsis. Pretreatment with 3OC8-HSL and subsequent pathogen invasion triggered an augmented burst of hydrogen peroxide, salicylic acid accumulation, and fortified expression of the pathogenesis-related genes PR1 and PR5. Upon PstDC3000 challenge, plants treated with 3OC8-HSL showed increased activities of defense-related enzymes including peroxidase, catalase, phenylalanine ammonialyase, and superoxide dismutase. In addition, the 3OC8-HSL-primed resistance to PstDC3000 in wild-type plants was impaired in plants expressing the bacterial NahG gene and in the npr1 mutant. Moreover, the expression levels of isochorismate synthases (ICS1), a critical salicylic acid biosynthesis enzyme, and two regulators of its expression, SARD1 and CBP60g, were potentiated by 3OC8-HSL pretreatment followed by pathogen inoculation. CONCLUSIONS: Our data indicate that 3OC8-HSL primes the Arabidopsis defense response upon hemibiotrophic bacterial infection and that 3OC8-HSL-primed resistance is dependent on the SA signaling pathway. These findings may help establish a novel strategy for the control of plant disease.


Assuntos
4-Butirolactona/análogos & derivados , Arabidopsis , Imunidade Vegetal/efeitos dos fármacos , Pseudomonas syringae/patogenicidade , Ácido Salicílico/metabolismo , 4-Butirolactona/farmacologia , Arabidopsis/genética , Arabidopsis/microbiologia , Proteínas de Arabidopsis/efeitos dos fármacos , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Proteínas de Ligação a Calmodulina/efeitos dos fármacos , Proteínas de Ligação a Calmodulina/genética , Proteínas de Ligação a Calmodulina/metabolismo , Genes de Plantas , Transferases Intramoleculares/efeitos dos fármacos , Transferases Intramoleculares/genética , Transferases Intramoleculares/metabolismo , Doenças das Plantas/microbiologia , Imunidade Vegetal/genética , Percepção de Quorum/fisiologia , Transdução de Sinais/efeitos dos fármacos
15.
Food Chem Toxicol ; 135: 110991, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31765699

RESUMO

The goal of this research was to study the selective pro-apoptotic effect of ligustilide on prostate-cancer-associated fibroblast in the tumor microenvironment and the related molecular mechanisms. The effects of ligustilide on cancer-associated fibroblasts (CAFs) and normal fibroblasts (NFs) isolated from the prostate were determined by MTT assay. Flow cytometry and cellular immunofluorescence were used to detect the effects of ligustilide on the cell cycle and apoptosis. Western blotting was used to detect the expression of apoptosis-related proteins after the action of ligustilide on CAFs. In the investigation, ligustilide had a selective pro-apoptotic effect on prostate-CAFs. After ligustilide treatment, the proportion of CAFs in the G2-M phase of the cell cycle increased, and the expression of apoptosis-related proteins (p-P53, Bcl-2, Caspase9 and Cytochrome C) changed. Ligustilide blocks the CAF cell cycle and induces the apoptosis of CAFs.


Assuntos
4-Butirolactona/análogos & derivados , Apoptose/efeitos dos fármacos , Fibroblastos Associados a Câncer/efeitos dos fármacos , Neoplasias da Próstata/patologia , Receptor 4 Toll-Like/metabolismo , 4-Butirolactona/farmacologia , Animais , Ciclo Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Xenoenxertos , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Receptor 4 Toll-Like/genética , Microambiente Tumoral
16.
Sci Total Environ ; 704: 135285, 2020 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-31822421

RESUMO

Fulvic acid (FA) can serve as electron shuttles between bacteria and electron acceptors. It explored the short-term effect of FA dose on nitrogen removal performance and N-acylated-L-homoserine lactones (AHLs) release change in the anaerobic ammonium oxidation (anammox) system. The results demonstrated that the total inorganic nitrogen removal efficiency increased with the FA dosages from 0.5 mM to 1 mM. FA addition improved anammox bacteria activity, together with extracellular polymeric substances production. FA addition from 0.5 mM to 1 mM stimulated AHLs release in both water and biomass phases, which indicated that the quorum sensing could be improved. These findings revealed that the addition of FA could improve quorum sensing and then enhance nitrogen removal performance.


Assuntos
4-Butirolactona/análogos & derivados , Benzopiranos , Nitrogênio , Eliminação de Resíduos Líquidos/métodos , Compostos de Amônio , Reatores Biológicos , Percepção de Quorum , Águas Residuárias
17.
Pest Manag Sci ; 76(3): 1142-1153, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31583806

RESUMO

BACKGROUND: Spirodiclofen is an acaricide that targets lipid biosynthesis by inhibiting acetyl-coenzyme A carboxylase. Spirodiclofen resistance in spider mites has been previously documented and was associated with overexpression of CYP392E10, a cytochrome P450 mono-oxygenase that metabolizes spirodiclofen. However, additional mechanisms have been suggested in several studies and a carboxyl/choline esterase gene, CCE04, was shown to be overexpressed in two genetically different strains, SR-VP and SR-TK, both exhibiting high spirodiclofen resistance levels. RESULTS: We identified two different CCE04 alleles in both resistant strains, CCE04SR-VP and CCE04London , with CCE04SR-VP being highly overexpressed. Isoelectric focusing analysis confirmed the overexpression of a single esterase isozyme, while copy number and random fragment length polymorphism analysis revealed that CCE04SR-VP overexpression was more likely due to selection for the CCE04SR-VP allele rather than gene amplification. Both CCE04 alleles were functionally expressed using the Pichia expression system. Functional enzyme assays revealed only limited kinetic differences between CCE04 isoforms for model substrates. In addition, inhibition/competition experiments with spirodiclofen suggested a similar interaction with both enzymes, whereas its active metabolite, spirodiclofen enol, did not inhibit enzyme activity. CONCLUSION: Our study suggests that selection with spirodiclofen results in enrichment of a specific allele of CCE04 (CCE04SR-VP ) in two genetically independent strains, which is highly overexpressed. Based on kinetic enzyme data, however, quantitative rather than qualitative differences between CCE04SR-VP and CCE04London seem more likely to be involved in resistance. Our findings are discussed in the light of a possible spirodiclofen resistance mechanism, with sequestration of spirodiclofen by CCE04SR-VP being a likely hypothesis. © 2019 Society of Chemical Industry.


Assuntos
Acaricidas , Tetranychidae , 4-Butirolactona/análogos & derivados , Alelos , Animais , Colina , Esterases , Compostos de Espiro
18.
Microbiol Res ; 231: 126354, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31678651

RESUMO

Quorum sensing (QS) in rhizobia regulates diverse processes determining the success and efficiency of association with the legume host. Despite the notable importance of QS as well as the well-known underlying variability in the genomic and metabolic components thereof, its study in rhizobia is largely restricted to few laboratory strains. In this work, QS phenomenon in the rhizobia nodulating pigeon pea- one of the most important legume crops of the global-south, is characterized. Using 16S rRNA and recombinaseA sequencing analysis, the selected QS-positive and host-beneficial isolates were identified to be taxonomically affiliated to the genus Ensifer. Their QS components, including homologues of QS genes, and the repertoire of N-acyl homoserine lactone (AHL) autoinducers were identified. Sequences of the QS homologues showed significant variabilities ranging from 10 to >20% with the known Ensifer sequences. Autoinducer profiling using LC-MS/MS revealed the production of long and short chain AHLs variably by the isolates, including 3-oxo-C12-homoserine lactone (3-O-C12-HSL) and 3-OH-C16-HSL as their first report in Rhizobiaceae. Motility and attachment- two of the most crucial traits for effective establishment on host roots were discovered to be QS dependent in in vitro analysis and the same was confirmed using expression analysis of their regulatory genes using qRT-PCR; both revealing a QS mediated repression of motility and promotion of attachment. This study highlights that Ensifer nodulating pigeon pea, although with significant variance in the anatomy of their QS components, regulate symbiotically crucial cell-processes via QS in a scheme that is conserved in multiple genera.


Assuntos
4-Butirolactona/análogos & derivados , Cajanus/microbiologia , Nodulação , Percepção de Quorum , Sinorhizobium , 4-Butirolactona/química , 4-Butirolactona/genética , 4-Butirolactona/metabolismo , Proteínas de Bactérias/genética , Cajanus/crescimento & desenvolvimento , Regulação Bacteriana da Expressão Gênica , Filogenia , Percepção de Quorum/genética , Percepção de Quorum/fisiologia , RNA Ribossômico 16S , Rhizobiaceae/classificação , Rhizobiaceae/isolamento & purificação , Rhizobiaceae/metabolismo , Sinorhizobium/isolamento & purificação , Sinorhizobium/metabolismo , Simbiose
19.
Water Res ; 169: 115193, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31670083

RESUMO

The positive roles of N-acyl homoserine lactone (AHL)-mediated quorum sensing (QS) in aerobic granular sludge (AGS) have been widely acknowledged. However, it is not feasible to manipulate granulation via direct addition of AHL chemicals or AHL-producing strains. Here, several strains with high AHL-producing capacity were successfully isolated from AGS. These QS strains were cultivated, mixed as a consortium, and then divided into two groups: AHLs supernatant and bacterial cells encapsulated in sodium alginate (CEBs). The potential of QS regulation, via doses of AHLs supernatant and CEBs, in accelerating granulation was evaluated. Results clearly indicated that short-term (days 21-70) addition of AHLs supernatant led to a rapid specific growth rate (0.08 d-1), compact structure without filamentous bacteria overgrowth, excellent settlement performance (SVI10 37.2 mL/g), and a high integrity coefficient (4.4%) of the granules. Sustainable release of AHLs (mainly C6- and C8-HSL) was induced by exogenous AHLs, possibly attributed to the enrichment of the genera Aeromonas and Pseudomonas. Further, tryptophan and aromatic protein substances were produced to maintain structural stability, suggesting that short-term QS regulation had long-term positive effects on the characteristics of AGS. By comparison, the addition of CEBs posed negligible or negative impact on the granulation, as evidenced by the rupture of smaller aggregates and poor characteristics of AGS. Overall, augmentation of the signaling content via addition of AHLs supernatant from QS strains is an economical and feasible regulation strategy to accelerate granulation and sustain long-term structural stability.


Assuntos
4-Butirolactona , Percepção de Quorum , 4-Butirolactona/análogos & derivados , Acil-Butirolactonas , Bactérias , Esgotos
20.
Environ Pollut ; 257: 113352, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31672371

RESUMO

The interference of nonylphenol (NP) with humans and animals, especially in hormone systems, has been well-studied. There is rarely any record of its effect on bacteria, which dominate in various environments. In our study, we employed Pseudomonas aeruginosa PAO1 as a model microorganism and took its common lifestyle biofilm, mainly regulated by quorum sensing (QS), as a cut-in point to investigate the effect of NP (1, 5, 10 mg L-1) on bacteria. The results showed that more than 5 mg L-1 of NP did interfere with biofilm formation and affected bacterial QS. In detail, the LasI/R circuit, but not the RhlI/R circuit, was considerably obstructed. The decrease in lasI and lasR expression resulted in a significant reduction in N-3-oxo-dodecanoyl homoserine lactone (3OC12-HSL) signals and the downstream production of elastases. Docking results indicated the binding of NP with LasR protein, simulating the binding of 3OC12-HSL with LasR protein, which explained the obstruction of the LasIR circuit. We concluded that NP competed with 3OC12-HSL and blocked 3OC12-HSL binding with the LasR protein, resulting in a direct interference in bacterial biofilm formation. This is the first report of NP interference with bacterial signaling, which is not only helpful to understand the effect of NP on various ecosystems, but is also beneficial to enrich our knowledge of inter-kingdom communication.


Assuntos
Biofilmes/efeitos dos fármacos , Fenóis/toxicidade , Pseudomonas aeruginosa/efeitos dos fármacos , Percepção de Quorum/efeitos dos fármacos , 4-Butirolactona/análogos & derivados , 4-Butirolactona/genética , Proteínas de Bactérias/metabolismo , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Pseudomonas aeruginosa/genética
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