Cupriavidus sp. HN-2, a Novel Quorum Quenching Bacterial Isolate, is a Potent Biocontrol Agent Against Xanthomonas campestris pv. campestris

Diffusible signal factor (DSF) represents a family of widely conserved quorum sensing (QS) signals involved in the regulation of virulence factor production in many Gram-negative bacterial pathogens. Quorum quenching, which disrupts QS either by degradation of QS signals or interference of signal generation or perception, is a promising strategy for prevention and control of QS-mediated bacterial infections. In this study, a novel DSF-degrading strain, HN-2, was isolated from contaminated soil and identified as Cupriavidus sp. The isolate exhibited superior DSF degradation activity and completely degraded 2 mmol·L–1 of DSF within 24 h. Analysis of the degradation products of DSF by gas chromatography–mass spectrometry led to the identification of trans-2-decenoic acid methyl ester as the main intermediate product, suggesting that DSF could be degraded by oxidation and hydroxylation. Moreover, this study presents for the first time, evidence that Cupriavidus sp. can reduce the black rot disease caused by Xanthomonas campestris pv. campestris (Xcc). Application of the HN-2 strain as a biocontrol agent could substantially reduce the disease severity. These findings reveal the biochemical basis of a highly efficient DSF-degrading bacterial isolate and present a useful agent for controlling infectious diseases caused by DSF-dependent bacterial pathogens.

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Characterization of a Novel Quorum-Quenching Bacterial Strain, Burkholderia anthina HN-8, and Its Biocontrol Potential against Black Rot Disease Caused by Xanthomonas campestris pv. campestris

Microorganisms ◽

10.3390/microorganisms8101485 ◽

2020 ◽

Vol 8 (10) ◽

pp. 1485

Author(s):

Tian Ye ◽

Wenping Zhang ◽

Zhixuan Feng ◽

Xinghui Fan ◽

Xudan Xu ◽

...

Keyword(s):

Bacterial Infections ◽

Xanthomonas Campestris ◽

Bacterial Pathogens ◽

Quorum Quenching ◽

Gas Chromatography Mass Spectrometry ◽

Black Rot ◽

Degrading Bacterium ◽

Diffusible Signal Factor ◽

Rot Disease ◽

Xanthomonas Campestris Pv Campestris

Diffusible signal factor (DSF) is a type of cis unsaturated fatty acid, with a chemical structure of 11-methyl-2-dodecylene acid. DSF is widely conserved in a variety of Gram-negative bacterial pathogens and is involved in the regulation of pathogenic virulence. Quorum quenching (QQ) is a promising strategy for preventing and controlling quorum sensing (QS)-mediated bacterial infections by interfering with the QS system of pathogens. In this study, a novel DSF-degrading bacterium, Burkholderia anthina strain HN-8, was isolated and characterized for its degradation ability and potential biocontrol of black rot disease caused by Xanthomonas campestris pv. campestris (Xcc). The HN-8 strain exhibited superb DSF degradation activity and completely degraded 2 mM DSF within 48 h. In addition, we present the first evidence of bacterium having a metabolic pathway for the complete degradation and metabolism of DSF. Analysis of DSF metabolic products by gas chromatography–mass spectrometry led to the identification of dodecanal as the main intermediate product, revealing that DSF could be degraded via oxidation–reduction. Furthermore, application of strain HN-8 as a potent biocontrol agent was able to significantly reduce the severity of black rot disease in radishes and Chinese cabbage. Taken together, these results shed light on the QQ mechanisms of DSF, and they provide useful information showing the potential for the biocontrol of infectious diseases caused by DSF-dependent bacterial pathogens.

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Identification of FadT as a Novel Quorum Quenching Enzyme for the Degradation of Diffusible Signal Factor in Cupriavidus pinatubonensis Strain HN-2

International Journal of Molecular Sciences ◽

10.3390/ijms22189862 ◽

2021 ◽

Vol 22 (18) ◽

pp. 9862

Author(s):

Xudan Xu ◽

Tian Ye ◽

Wenping Zhang ◽

Tian Zhou ◽

Xiaofan Zhou ◽

...

Keyword(s):

Bacterial Infections ◽

Xanthomonas Campestris ◽

Cell Communication ◽

Maximal Activity ◽

Quorum Quenching ◽

Site Directed Mutagenesis ◽

Diffusible Signal Factor ◽

High Enzymatic Activity ◽

Xanthomonas Campestris Pv Campestris ◽

Potential Use

Quorum sensing (QS) is a microbial cell–cell communication mechanism and plays an important role in bacterial infections. QS-mediated bacterial infections can be blocked through quorum quenching (QQ), which hampers signal accumulation, recognition, and communication. The pathogenicity of numerous bacteria, including Xanthomonas campestris pv. campestris (Xcc), is regulated by diffusible signal factor (DSF), a well-known fatty acid signaling molecule of QS. Cupriavidus pinatubonensis HN-2 could substantially attenuate the infection of XCC through QQ by degrading DSF. The QQ mechanism in strain HN-2, on the other hand, is yet to be known. To understand the molecular mechanism of QQ in strain HN-2, we used whole-genome sequencing and comparative genomics studies. We discovered that the fadT gene encodes acyl-CoA dehydrogenase as a novel QQ enzyme. The results of site-directed mutagenesis demonstrated the requirement of fadT gene for DSF degradation in strain HN-2. Purified FadT exhibited high enzymatic activity and outstanding stability over a broad pH and temperature range with maximal activity at pH 7.0 and 35 °C. No cofactors were required for FadT enzyme activity. The enzyme showed a strong ability to degrade DSF. Furthermore, the expression of fadT in Xcc results in a significant reduction in the pathogenicity in host plants, such as Chinese cabbage, radish, and pakchoi. Taken together, our results identified a novel DSF-degrading enzyme, FadT, in C. pinatubonensis HN-2, which suggests its potential use in the biological control of DSF-mediated pathogens.

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A Quorum Quenching Bacterial Isolate Contains Multiple Substrate-Inducible Genes Conferring Degradation of Diffusible Signal Factor

Applied and Environmental Microbiology ◽

10.1128/aem.02930-19 ◽

2020 ◽

Vol 86 (7) ◽

Cited By ~ 4

Author(s):

Huishan Wang ◽

Lisheng Liao ◽

Shaohua Chen ◽

Lian-Hui Zhang

Keyword(s):

Molecular Basis ◽

Bacterial Isolate ◽

Bacterial Pathogens ◽

Quorum Quenching ◽

Gram Negative ◽

Content Type ◽

Signal Degradation ◽

Highly Active ◽

Diffusible Signal Factor ◽

Degradation Activity

ABSTRACT Quorum quenching, which disrupts quorum sensing (QS) by either degradation of QS signals or interference of signal generation or perception, is a promising strategy for the prevention and control of QS-mediated bacterial infections. Diffusible signal factor (DSF) is widely conserved in many Gram-negative bacterial pathogens. In this study, we developed an efficient method for screening of highly active DSF degradation microorganisms. Among them, Pseudomonas sp. strain HS-18 showed a superior DSF degradation activity. Bioinformatics and genetic analyses showed that at least 4 genes, designated digA to digD, encoding fatty acyl coenzyme A ligase homologues, are responsible for DSF signal degradation. Interestingly, all 4 dig genes were induced by exogenous DSF, with digA being the most significantly induced. Expression of the dig genes in Xanthomonas campestris pv. campestris markedly reduced the accumulation of endogenous DSF, decreased production of virulence factors, and attenuated bacterial virulence on host plants. Similarly, application of strain HS-18 as a biocontrol agent could substantially reduce the disease severity caused by X. campestris pv. campestris. These results unveil the molecular basis of a highly efficient DSF degradation bacterial isolate and present useful genes and biocontrol agents for control of the infectious diseases caused by DSF-dependent bacterial pathogens. IMPORTANCE Diffusible signal factor (DSF) represents a family of widely conserved quorum sensing signals involved in the regulation of virulence factor production in many Gram-negative bacterial pathogens. In this study, we developed a novel and efficient method for screening highly active DSF degradation microorganisms. With this method, we identified a bacterial isolate, Pseudomonas sp. strain HS-18, with a superb DSF degradation activity. We further found that strain HS-18 contains 4 genes responsible for DSF signal degradation, and significantly, these were induced by exogenous DSF molecules. These findings unveil the molecular basis of a highly efficient DSF degradation bacterial isolate and present useful methods, genes, and agents for control of the infectious diseases caused by DSF-dependent bacterial pathogens.

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Quorum Quenching in a Novel Acinetobacter sp. XN-10 Bacterial Strain against Pectobacterium carotovorum subsp. carotovorum

Microorganisms ◽

10.3390/microorganisms8081100 ◽

2020 ◽

Vol 8 (8) ◽

pp. 1100 ◽

Cited By ~ 1

Author(s):

Wenping Zhang ◽

Qingqing Luo ◽

Yiyin Zhang ◽

Xinghui Fan ◽

Tian Ye ◽

...

Keyword(s):

Bacterial Pathogens ◽

Quorum Quenching ◽

Homoserine Lactone ◽

Gas Chromatography Mass Spectrometry ◽

Pectobacterium Carotovorum ◽

Degrading Bacterium ◽

Family Analysis ◽

Carotovorum Subsp ◽

Acinetobacter Sp ◽

Tissue Maceration

Quorum sensing (QS) is a cell density-dependent mechanism that regulates the expression of specific genes in microbial cells. Quorum quenching (QQ) is a promising strategy for attenuating pathogenicity by interfering with the QS system of pathogens. N-Acyl-homoserine lactones (AHLs) act as signaling molecules in many Gram-negative bacterial pathogens and have received wide attention. In this study, a novel, efficient AHL-degrading bacterium, Acinetobacter sp. strain XN-10, was isolated from agricultural contaminated soil and evaluated for its degradation efficiency and potential use against QS-mediated pathogens. Strain XN-10 could effectively degrade N-(3-oxohexanoyl)-L-homoserine lactone (OHHL), N-hexanoyl-L-homoserine lactone (C6HSL), N-(3-oxododecanoyl)-L-homoserine lactone (3OC12HSL), and N-(3-oxooctanoyl)-L-homoserine lactone (3OC8HSL), which all belong to the AHL family. Analysis of AHL metabolic products by gas chromatography–mass spectrometry (GC-MS) led to the identification of N-cyclohexyl-propanamide, and pentanoic acid, 4-methyl, methyl ester as the main intermediate metabolites, revealing that AHL could be degraded by hydrolysis and dehydroxylation. All intermediates were transitory and faded away without any non-cleavable metabolites at the end of the experiment. Furthermore, strain XN-10 significantly attenuated the pathogenicity of Pectobacterium carotovorum subsp. carotovorum (Pcc) to suppress tissue maceration in carrots, potatoes, and Chinese cabbage. Taken together, our results shed light on the QQ mechanism of a novel AHL-degrading bacterial isolate, and they provide useful information which show potential for biocontrol of infectious diseases caused by AHL-dependent bacterial pathogens.

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Acinetobacter lactucae Strain QL-1, a Novel Quorum Quenching Candidate Against Bacterial Pathogen Xanthomonas campestris pv. campestris

Frontiers in Microbiology ◽

10.3389/fmicb.2019.02867 ◽

2019 ◽

Vol 10 ◽

Cited By ~ 7

Author(s):

Tian Ye ◽

Tian Zhou ◽

Xinghui Fan ◽

Pankaj Bhatt ◽

Lianhui Zhang ◽

...

Keyword(s):

Xanthomonas Campestris ◽

Bacterial Pathogen ◽

Quorum Quenching ◽

Xanthomonas Campestris Pv Campestris

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Whole-Genome Sequencing Analysis of Quorum Quenching Bacterial Strain Acinetobacter lactucae QL-1 Identifies the FadY Enzyme for Degradation of the Diffusible Signal Factor

International Journal of Molecular Sciences ◽

10.3390/ijms21186729 ◽

2020 ◽

Vol 21 (18) ◽

pp. 6729 ◽

Cited By ~ 1

Author(s):

Tian Ye ◽

Tian Zhou ◽

Xudan Xu ◽

Wenping Zhang ◽

Xinghui Fan ◽

...

Keyword(s):

Whole Genome Sequencing ◽

Genome Sequencing ◽

Xanthomonas Campestris ◽

Molecular Mechanisms ◽

Bacterial Pathogens ◽

Quorum Quenching ◽

Site Directed Mutagenesis ◽

Whole Genome ◽

Sequencing Analysis ◽

Diffusible Signal Factor

The diffusible signal factor (DSF) is a fatty acid signal molecule and is widely conserved in various Gram-negative bacteria. DSF is involved in the regulation of pathogenic virulence in many bacterial pathogens, including Xanthomonas campestris pv. campestris (Xcc). Quorum quenching (QQ) is a potential approach for preventing and controlling DSF-mediated bacterial infections by the degradation of the DSF signal. Acinetobacter lactucae strain QL-1 possesses a superb DSF degradation ability and effectively attenuates Xcc virulence through QQ. However, the QQ mechanisms in strain QL-1 are still unknown. In the present study, whole-genome sequencing and comparative genomics analysis were conducted to identify the molecular mechanisms of QQ in strain QL-1. We found that the fadY gene of QL-1 is an ortholog of XccrpfB, a known DSF degradation gene, suggesting that strain QL-1 is capable of inactivating DSF by QQ enzymes. The results of site-directed mutagenesis indicated that fadY is required for strain QL-1 to degrade DSF. The determination of FadY activity in vitro revealed that the fatty acyl-CoA synthetase FadY had remarkable catalytic activity. Furthermore, the expression of fadY in transformed Xcc strain XC1 was investigated and shown to significantly attenuate bacterial pathogenicity on host plants, such as Chinese cabbage and radish. This is the first report demonstrating a DSF degradation enzyme from A. lactucae. Taken together, these findings shed light on the QQ mechanisms of A. lactucae strain QL-1, and provide useful enzymes and related genes for the biocontrol of infectious diseases caused by DSF-dependent bacterial pathogens.

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Chemical composition and antibacterial activity of commercial copaiba (Copaifera spp.) oils against bacterial pathogens isolated from postoperative mammoplasty surgery

Research Society and Development ◽

10.33448/rsd-v9i10.8593 ◽

2020 ◽

Vol 9 (10) ◽

pp. e1869108593

Author(s):

Raquel Costa Machado ◽

Ana Karina Vargas Soares ◽

Isabela Carvalho dos Santos ◽

Wanessa de Campos Bortolucci ◽

Luis Fernando Espinoza Luizar ◽

...

Keyword(s):

Bacterial Infections ◽

Bacterial Resistance ◽

Synergistic Effects ◽

Bacterial Pathogens ◽

Mass Spectrometry Analysis ◽

Antibacterial Action ◽

Gas Chromatography Mass Spectrometry ◽

Aureus Strain ◽

Clinical Samples

Plastic surgeries are considered clean or potentially contaminated procedures. The incidence of infection in reduction mammoplasty is 1.1 to 22% and the main etiological agents are bacteria found on the skin and mucous membranes such as Staphylococcus aureus. Due to the increase in bacterial resistance with the widespread use of antibiotics, identify natural compounds with antibacterial action on postoperative surgery wounds are fundamental. Thus, the objective of this research was the identification of compounds and assessment of the antibacterial action of Copaifera spp. (copaiba) oil against standard strains and bacterial pathogens isolated from postoperative mammoplasty surgery. For this, four commercial copaiba oils (1, 2, 3 and 4) were submitted to a gas chromatography/mass spectrometry analysis. The in-vitro antimicrobial activity and the minimum inhibitory concentration (MIC) of oils on standard strains and clinical samples, as well as the disk antibiotics sensitivity and the synergistic effect of the oils and antibiotics, were assessed. A total of 72 compounds were identified, accounting for ~99% of the volatile constituents in the oils. Sesquiterpenes comprised 67.24– 90.11% of the components, with β-caryophyllene being the most common. Oils 1 and 2 were the most active on the S. aureus strain, with MIC similarto Oil 3, while Oil 4presented no activity. The same pattern was observed in the clinical samples. In addition, Oil 2 presented synergism when associated with amoxicillin. The synergistic effects of Copaiba oils may represent a source of therapeutic compounds against bacterial infections in surgical wound.

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