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Li X, Wang G, Guo Q, Cui B, Wang M, Song S, Yang L, Deng Y. Membrane-enclosed Pseudomonas quinolone signal attenuates bacterial virulence by interfering with quorum sensing. Appl Environ Microbiol 2023; 89:e0118423. [PMID: 37796010 PMCID: PMC10617430 DOI: 10.1128/aem.01184-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 08/07/2023] [Indexed: 10/06/2023] Open
Abstract
Outer membrane vesicle (OMV)-delivered Pseudomonas quinolone signal (PQS) plays a critical role in cell-cell communication in Pseudomonas aeruginosa. However, the functions and mechanisms of membrane-enclosed PQS in interspecies communication in microbial communities are not clear. Here, we demonstrate that PQS delivered by both OMVs from P. aeruginosa and liposome reduces the competitiveness of Burkholderia cenocepacia, which usually shares the same niche in the lungs of cystic fibrosis patients, by interfering with quorum sensing (QS) in B. cenocepacia through the LysR-type regulator ShvR. Intriguingly, we found that ShvR regulates the production of the QS signals cis-2-dodecenoic acid (BDSF) and N-acyl homoserine lactone (AHL) by directly binding to the promoters of signal synthase-encoding genes. Perception of PQS influences the regulatory activity of ShvR and thus ultimately reduces QS signal production and virulence in B. cenocepacia. Our findings provide insights into the interspecies communication mediated by the membrane-enclosed QS signal among bacterial species residing in the same microbial community.IMPORTANCEQuorum sensing (QS) is a ubiquitous cell-to-cell communication mechanism. Previous studies showed that Burkholderia cenocepacia mainly employs cis-2-dodecenoic acid (BDSF) and N-acyl homoserine lactone (AHL) QS systems to regulate biological functions and virulence. Here, we demonstrate that Pseudomonas quinolone signal (PQS) delivered by outer membrane vesicles from Pseudomonas aeruginosa or liposome attenuates B. cenocepacia virulence by targeting the LysR-type regulator ShvR, which regulates the production of the QS signals BDSF and AHL in B. cenocepacia. Our results not only suggest the important roles of membrane-enclosed PQS in interspecies and interkingdom communications but also provide a new perspective on the use of functional nanocarriers loaded with QS inhibitors for treating pathogen infections.
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Affiliation(s)
- Xia Li
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, Guangdong, China
| | - Gerun Wang
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, Guangdong, China
| | - Quan Guo
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, Guangdong, China
| | - Binbin Cui
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, Guangdong, China
| | - Mingfang Wang
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, Guangdong, China
| | - Shihao Song
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, Guangdong, China
- School of Pharmaceutical Sciences, Hainan University, Haikou, Hainan, China
| | - Liang Yang
- School of Medicine, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Yinyue Deng
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, Guangdong, China
- School of Pharmaceutical Sciences, Hainan University, Haikou, Hainan, China
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Nyanasegran PK, Nathan S, Firdaus-Raih M, Muhammad NAN, Ng CL. Biofilm Signaling, Composition and Regulation in Burkholderia pseudomallei. J Microbiol Biotechnol 2023; 33:15-27. [PMID: 36451302 PMCID: PMC9899790 DOI: 10.4014/jmb.2207.07032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 10/10/2022] [Accepted: 10/11/2022] [Indexed: 12/04/2022]
Abstract
The incidence of melioidosis cases caused by the gram-negative pathogen Burkholderia pseudomallei (BP) is seeing an increasing trend that has spread beyond its previously known endemic regions. Biofilms produced by BP have been associated with antimicrobial therapy limitation and relapse melioidosis, thus making it urgently necessary to understand the mechanisms of biofilm formation and their role in BP biology. Microbial cells aggregate and enclose within a self-produced matrix of extracellular polymeric substances (EPSs) to form biofilm. The transition mechanism of bacterial cells from planktonic state to initiate biofilm formation, which involves the formation of surface attachment microcolonies and the maturation of the biofilm matrix, is a dynamic and complex process. Despite the emerging findings on the biofilm formation process, systemic knowledge on the molecular mechanisms of biofilm formation in BP remains fractured. This review provides insights into the signaling systems, matrix composition, and the biosynthesis regulation of EPSs (exopolysaccharide, eDNA and proteins) that facilitate the formation of biofilms in order to present an overview of our current knowledge and the questions that remain regarding BP biofilms.
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Affiliation(s)
| | - Sheila Nathan
- Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia
| | - Mohd Firdaus-Raih
- Institute of Systems Biology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia,Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia
| | - Nor Azlan Nor Muhammad
- Institute of Systems Biology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia
| | - Chyan Leong Ng
- Institute of Systems Biology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia,Corresponding author Phone: +03 8921 4561 Fax: +603 8921 3398 E-mail:
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Zhu X, Chen WJ, Bhatt K, Zhou Z, Huang Y, Zhang LH, Chen S, Wang J. Innovative microbial disease biocontrol strategies mediated by quorum quenching and their multifaceted applications: A review. FRONTIERS IN PLANT SCIENCE 2023; 13:1063393. [PMID: 36714722 PMCID: PMC9878147 DOI: 10.3389/fpls.2022.1063393] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 12/15/2022] [Indexed: 06/12/2023]
Abstract
With the increasing resistance exhibited by undesirable bacteria to traditional antibiotics, the need to discover alternative (or, at least, supplementary) treatments to combat chemically resistant bacteria is becoming urgent. Quorum sensing (QS) refers to a novel bacterial communication system for monitoring cell density and regulation of a network of gene expression that is mediated by a group of signaling molecules called autoinducers (AIs). QS-regulated multicellular behaviors include biofilm formation, horizontal gene transfer, and antibiotic synthesis, which are demonstrating increasing pathogenicity to plants and aquacultural animals as well as contamination of wastewater treatment devices. To inhibit QS-regulated microbial behaviors, the strategy of quorum quenching (QQ) has been developed. Different quorum quenchers interfere with QS through different mechanisms, such as competitively inhibiting AI perception (e.g., by QS inhibitors) and AI degradation (e.g., by QQ enzymes). In this review, we first introduce different signaling molecules, including diffusible signal factor (DSF) and acyl homoserine lactones (AHLs) for Gram-negative bacteria, AIPs for Gram-positive bacteria, and AI-2 for interspecies communication, thus demonstrating the mode of action of the QS system. We next exemplify the QQ mechanisms of various quorum quenchers, such as chemical QS inhibitors, and the physical/enzymatic degradation of QS signals. We devote special attention to AHL-degrading enzymes, which are categorized in detail according to their diverse catalytic mechanisms and enzymatic properties. In the final part, the applications and advantages of quorum quenchers (especially QQ enzymes and bacteria) are summarized in the context of agricultural/aquacultural pathogen biocontrol, membrane bioreactors for wastewater treatment, and the attenuation of human pathogenic bacteria. Taken together, we present the state-of-the-art in research considering QS and QQ, providing theoretical evidence and support for wider application of this promising environmentally friendly biocontrol strategy.
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Affiliation(s)
- Xixian Zhu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Plant Protection, South China Agricultural University, Guangzhou, China
| | - Wen-Juan Chen
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Plant Protection, South China Agricultural University, Guangzhou, China
| | - Kalpana Bhatt
- Department of Food Science, Purdue University, West Lafayette, IN, United States
| | - Zhe Zhou
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Plant Protection, South China Agricultural University, Guangzhou, China
| | - Yaohua Huang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Plant Protection, South China Agricultural University, Guangzhou, China
| | - Lian-Hui Zhang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Plant Protection, South China Agricultural University, Guangzhou, China
| | - Shaohua Chen
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Plant Protection, South China Agricultural University, Guangzhou, China
| | - Junxia Wang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Plant Protection, South China Agricultural University, Guangzhou, China
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Yu H, Chen WJ, Bhatt K, Zhou Z, Zhu X, Liu S, He J, Zhang LH, Chen S, Wang H, Liao L. A novel bacterial strain Burkholderia sp. F25 capable of degrading diffusible signal factor signal shows strong biocontrol potential. FRONTIERS IN PLANT SCIENCE 2022; 13:1071693. [PMID: 36507382 PMCID: PMC9730286 DOI: 10.3389/fpls.2022.1071693] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Accepted: 11/03/2022] [Indexed: 06/12/2023]
Abstract
Vast quantities of synthetic pesticides have been widely applied in various fields to kill plant pathogens, resulting in increased pathogen resistance and decreased effectiveness of such chemicals. In addition, the increased presence of pesticide residues affects living organisms and the environment largely on a global scale. To mitigate the impact of crop diseases more sustainably on plant health and productivity, there is a need for more safe and more eco-friendly strategies as compared to chemical prevention. Quorum sensing (QS) is an intercellular communication mechanism in a bacterial population, through which bacteria adjust their population density and behavior upon sensing the levels of signaling molecules in the environment. As an alternative, quorum quenching (QQ) is a promising new strategy for disease control, which interferes with QS by blocking intercellular communication between pathogenic bacteria to suppress the expression of disease-causing genes. Black rot caused by Xanthomonas campestris pv. campestris (Xcc) is associated with the diffusible signal factor (DSF). As detailed in this study, a new QQ strain F25, identified as Burkholderia sp., displayed a superior ability to completely degrade 2 mM of DSF within 72 h. The main intermediate product in the biodegradation of DSF was identified as n-decanoic acid, based on gas chromatography-mass spectrometry (GC-MS). A metabolic pathway for DSF by strain F25 is proposed, based on the chemical structure of DSF and its intermediates, demonstrating the possible degradation of DSF via oxidation-reduction. The application of strain F25 and its crude enzyme as biocontrol agents significantly attenuated black rot caused by Xcc, and inhibited tissue maceration in the host plant Raphanus sativus L., without affecting the host plant. This suggests that agents produced from strain F25 and its crude enzyme have promising applications in controlling infectious diseases caused by DSF-dependent bacterial pathogens. These findings are expected to provide a new therapeutic strategy for controlling QS-mediated plant diseases.
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Affiliation(s)
- Hongxiao Yu
- Department of Plant Pathology, College of Plant Protection, South China Agricultural University, Guangzhou, China
| | - Wen-Juan Chen
- Department of Plant Pathology, College of Plant Protection, South China Agricultural University, Guangzhou, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Kalpana Bhatt
- Department of Botany and Microbiology, Gurukula Kangri University, Haridwar, Uttarakhand, India
| | - Zhe Zhou
- Department of Plant Pathology, College of Plant Protection, South China Agricultural University, Guangzhou, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Xixian Zhu
- Department of Plant Pathology, College of Plant Protection, South China Agricultural University, Guangzhou, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Siqi Liu
- Department of Plant Pathology, College of Plant Protection, South China Agricultural University, Guangzhou, China
| | - Jiehua He
- Department of Plant Pathology, College of Plant Protection, South China Agricultural University, Guangzhou, China
| | - Lian-Hui Zhang
- Department of Plant Pathology, College of Plant Protection, South China Agricultural University, Guangzhou, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Shaohua Chen
- Department of Plant Pathology, College of Plant Protection, South China Agricultural University, Guangzhou, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Huishan Wang
- Department of Plant Pathology, College of Plant Protection, South China Agricultural University, Guangzhou, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Lisheng Liao
- Department of Plant Pathology, College of Plant Protection, South China Agricultural University, Guangzhou, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
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Abstract
Burkholderia cenocepacia is a human opportunistic pathogen that mostly employs two types of quorum-sensing (QS) systems to regulate its various biological functions and pathogenicity: the cis-2-dodecenoic acid (BDSF) system and the N-acyl homoserine lactone (AHL) system. In this study, we reported that oridonin, which was screened from a collection of natural products, disrupted important B. cenocepacia phenotypes, including motility, biofilm formation, protease production, and virulence. Genetic and biochemical analyses showed that oridonin inhibited the production of BDSF and AHL signals by decreasing the expression of their synthase-encoding genes. Furthermore, we revealed that oridonin directly binds to the regulator RqpR of the two-component system RqpSR that dominates the above-mentioned QS systems to inhibit the expression of the BDSF and AHL signal synthase-encoding genes. Oridonin also binds to the transcriptional regulator CepR of the cep AHL system to inhibit its binding to the promoter of bclACB. These findings suggest that oridonin could potentially be developed as a new QS inhibitor against pathogenic B. cenocepacia. IMPORTANCE Burkholderia cenocepacia is an important human opportunistic pathogen that can cause life-threatening infections in susceptible individuals. It employs quorum-sensing (QS) systems to regulate biological functions and virulence. In this study, we have identified a lead compound, oridonin, that is capable of interfering with B. cenocepacia QS signaling and physiology. We demonstrate that oridonin suppressed cis-2-dodecenoic acid (BDSF) and N-acyl homoserine lactone (AHL) signal production and attenuated virulence in B. cenocepacia. Oridonin also impaired QS-regulated phenotypes in various Burkholderia species. These results suggest that oridonin could interfere with QS signaling in many Burkholderia species and might be developed as a new antibacterial agent.
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BDSF Is a Degradation-Prone Quorum-Sensing Signal Detected by the Histidine Kinase RpfC of Xanthomonas campestris pv. campestris. Appl Environ Microbiol 2022; 88:e0003122. [PMID: 35369702 DOI: 10.1128/aem.00031-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Diffusible signal factors (DSFs) are medium-chain fatty acids that induce bacterial quorum sensing. Among these compounds, BDSF is a structural analog of DSF that is commonly detected in bacterial species, and it is the predominant in planta quorum-sensing signal in Xanthomonas campestris. How BDSF is sensed in Xanthomonas spp. and the functional diversity between BDSF and DSF remain unclear. In this study, we generated genetic and biochemical evidence that BDSF is a low-active regulator of X. campestris pv. campestris quorum sensing, whereas trans-BDSF does not seem to be a signaling compound. BDSF is detected by the sensor histidine kinase RpfC. Although BDSF has relatively low physiological activities, it binds to the RpfC sensor with a high affinity and activates RpfC autophosphorylation to a level that is similar to that induced by DSF in vitro. The inconsistency in the physiological and biochemical activities of BDSF is not due to RpfC-RpfG phosphorylation or RpfG hydrolase. Neither BDSF nor DSF controls the phosphotransferase and phosphatase activities of RpfC or the ability of RpfG hydrolase activity to degrade the bacterial second messenger cyclic di-GMP. We demonstrated that BDSF is prone to degradation by RpfB, a critical fatty acyl coenzyme A ligase involved in the turnover of DSF-family signals. rpfB mutations lead to substantial increases in BDSF-induced quorum sensing. Although DSF and BDSF are similarly detected by RpfC, our data suggest that their differential degradation in cells is the major factor responsible for the diversity in their physiological effects. IMPORTANCE The diffusible signal factor (DSF) family consists of quorum-sensing signals employed by Gram-negative bacteria. These signals are a group of cis-2-unsaturated fatty acids, such as DSF, BDSF, IDSF, CDSF, and SDSF. However, the functional divergence of various DSF signals remains unclear. The present study demonstrates that though BDSF is a low active quorum-sensing signal, it binds histidine kinase RpfC with a higher affinity and activates RpfC autophosphorylation to the similar level as DSF. Rather than regulation of enzymatic activities of RpfC and its cognate response regulator RpfG encoding a c-di-GMP hydrolase, BDSF is prone to degradation in bacterial cells by RpfB, which effectively avoided the inhibition of bacterial growth by accumulating high concentrations of BDSF. Therefore, our study sheds new light on the functional differences of quorum-sensing signals and shows that bacteria balance quorum sensing and growth by fine-tuning concentrations of signaling chemicals.
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A c-di-GMP Signaling Cascade Controls Motility, Biofilm Formation, and Virulence in Burkholderia thailandensis. Appl Environ Microbiol 2022; 88:e0252921. [PMID: 35323023 DOI: 10.1128/aem.02529-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
As a key bacterial second messenger, cyclic di-GMP (c-di-GMP) regulates various physiological processes, such as motility, biofilm formation, and virulence. Cellular c-di-GMP levels are regulated by the opposing activities of diguanylate cyclases (DGCs) and phosphodiesterases (PDEs). Beyond that, the enzymatic activities of c-di-GMP metabolizing proteins are controlled by a variety of extracellular signals and intracellular physiological conditions. Here, we report that pdcA (BTH_II2363), pdcB (BTH_II2364), and pdcC (BTH_II2365) are cotranscribed in the same operon and are involved in a regulatory cascade controlling the cellular level of c-di-GMP in Burkholderia thailandensis. The GGDEF domain-containing protein PdcA was found to be a DGC that modulates biofilm formation, motility, and virulence in B. thailandensis. Moreover, the DGC activity of PdcA was inhibited by phosphorylated PdcC, a single-domain response regulator composed of only the phosphoryl-accepting REC domain. The phosphatase PdcB affects the function of PdcA by dephosphorylating PdcC. The observation that homologous operons of pdcABC are widespread among betaproteobacteria and gammaproteobacteria suggests a general mechanism by which the intracellular concentration of c-di-GMP is modulated to coordinate bacterial behavior and virulence. IMPORTANCE The transition from planktonic cells to biofilm cells is a successful strategy adopted by bacteria to survive in diverse environments, while the second messenger c-di-GMP plays an important role in this process. Cellular c-di-GMP levels are mainly controlled by modulating the activity of c-di-GMP-metabolizing proteins via the sensory domains adjacent to their enzymatic domains. However, in most cases how c-di-GMP-metabolizing enzymes are modulated by their sensory domains remains unclear. Here, we reveal a new c-di-GMP signaling cascade that regulates motility, biofilm formation, and virulence in B. thailandensis. While pdcA, pdcB, and pdcC constitute an operon, the phosphorylated PdcC binds the PAS sensory domain of PdcA to inhibit its DGC activity, with PdcB dephosphorylating PdcC to derepress the activity of PdcA. We also show this c-di-GMP regulatory model is widespread in the phylum Proteobacteria. Our study expands the current knowledge of how bacteria regulate intracellular c-di-GMP levels.
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The cis-2-dodecenoic acid (BDSF) quorum sensing system in Burkholderia cenocepacia. Appl Environ Microbiol 2022; 88:e0234221. [PMID: 34985987 DOI: 10.1128/aem.02342-21] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
It has been demonstrated that quorum sensing (QS) is widely employed by bacterial cells to coordinately regulate various group behaviors. Diffusible signal factor (DSF)-type signals have emerged as a growing family of conserved cell-cell communication signals. In addition to the DSF signal initially identified in Xanthomonas campestris pv. campestris, Burkholderia diffusible signal factor (BDSF, cis-2-dodecenoic acid) has been recognized as a conserved DSF-type signal with specific characteristics in both signal perception and transduction from DSF signals. Here, we review the history and current progress of the research of this type of signal, especially focusing on its biosynthesis, signaling pathways, and biological functions. We also discuss and explore the huge potential of targeting this kind of QS system as a new therapeutic strategy to control bacterial infections and diseases.
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A LysR Family Transcriptional Regulator Modulates Burkholderia cenocepacia Biofilm Formation and Protease Production. Appl Environ Microbiol 2021; 87:e0020221. [PMID: 33811025 PMCID: PMC8174753 DOI: 10.1128/aem.00202-21] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Quorum-sensing (QS) signals are widely employed by bacteria to regulate biological functions in response to cell densities. Previous studies showed that Burkholderia cenocepacia mostly utilizes two types of QS systems, including the N-acylhomoserine lactone (AHL) and cis-2-dodecenoic acid (BDSF) systems, to regulate biological functions. We demonstrated here that a LysR family transcriptional regulator, Bcal3178, controls the QS-regulated phenotypes, including biofilm formation and protease production, in B. cenocepacia H111. Expression of Bcal3178 at the transcriptional level was obviously downregulated in both the AHL-deficient and BDSF-deficient mutant strains compared to the wild-type H111 strain. It was further identified that Bcal3178 regulated target gene expression by directly binding to the promoter DNA regions. We also revealed that Bcal3178 was directly controlled by the AHL system regulator CepR. These results show that Bcal3178 is a new downstream component of the QS signaling network that modulates a subset of genes and functions coregulated by the AHL and BDSF QS systems in B. cenocepacia. IMPORTANCEBurkholderia cenocepacia is an important opportunistic pathogen in humans that utilizes the BDSF and AHL quorum-sensing (QS) systems to regulate biological functions and virulence. We demonstrated here that a new downstream regulator, Bcal3178 of the QS signaling network, controls biofilm formation and protease production. Bcal3178 is a LysR family transcriptional regulator modulated by both the BDSF and AHL QS systems. Furthermore, Bcal3178 controls many target genes, which are regulated by the QS systems in B. cenocepacia. Collectively, our findings depict a novel molecular mechanism with which QS systems regulate some target gene expression and biological functions by modulating the expression level of a LysR family transcriptional regulator in B. cenocepacia.
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The Roles of Microbial Cell-Cell Chemical Communication Systems in the Modulation of Antimicrobial Resistance. Antibiotics (Basel) 2020; 9:antibiotics9110779. [PMID: 33171916 PMCID: PMC7694446 DOI: 10.3390/antibiotics9110779] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 11/02/2020] [Accepted: 11/04/2020] [Indexed: 01/25/2023] Open
Abstract
Rapid emergence of antimicrobial resistance (AMR) has become a critical challenge worldwide. It is of great importance to understand how AMR is modulated genetically in order to explore new antimicrobial strategies. Recent studies have unveiled that microbial communication systems, which are known to play key roles in regulation of bacterial virulence, are also associated with the formation and regulation of AMR. These microbial cell-to-cell chemical communication systems, including quorum sensing (QS) and pathogen-host communication mechanisms, rely on detection and response of various chemical signal molecules, which are generated either by the microbe itself or host cells, to activate the expression of virulence and AMR genes. This article summarizes the generic signaling mechanisms of representative QS and pathogen-host communications systems, reviews the current knowledge regarding the roles of these chemical communication systems in regulation of AMR, and describes the strategies developed over the years for blocking bacterial chemical communication systems in disease control. The research progress in this field suggests that the bacterial cell-cell communication systems are a promising target not only for disease control but also for curbing the problem of microbial drug resistance.
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Kim HS, Cha E, Ham SY, Park JH, Nam S, Kwon H, Byun Y, Park HD. Linoleic acid inhibits Pseudomonas aeruginosa biofilm formation by activating diffusible signal factor-mediated quorum sensing. Biotechnol Bioeng 2020; 118:82-93. [PMID: 32880907 DOI: 10.1002/bit.27552] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 08/09/2020] [Accepted: 08/29/2020] [Indexed: 12/24/2022]
Abstract
Bacterial biofilm formation causes serious problems in various fields of medical, clinical, and industrial settings. Antibiotics and biocide treatments are typical methods used to remove bacterial biofilms, but biofilms are difficult to remove effectively from surfaces due to their increased resistance. An alternative approach to treatment with antimicrobial agents is using biofilm inhibitors that regulate biofilm development without inhibiting bacterial growth. In the present study, we found that linoleic acid (LA), a plant unsaturated fatty acid, inhibits biofilm formation under static and continuous conditions without inhibiting the growth of Pseudomonas aeruginosa. LA also influenced the bacterial motility, extracellular polymeric substance production, and biofilm dispersion by decreasing the intracellular cyclic diguanylate concentration through increased phosphodiesterase activity. Furthermore, quantitative gene expression analysis demonstrated that LA induced the expression of genes associated with diffusible signaling factor-mediated quorum sensing that can inhibit or induce the dispersion of P. aeruginosa biofilms. These results suggest that LA is functionally and structurally similar to a P. aeruginosa diffusible signaling factor (cis-2-decenoic acid) and, in turn, act as an agonist molecule in biofilm dispersion.
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Affiliation(s)
- Han-Shin Kim
- Korean Peninsula Infrastructure Special Committee, Korea Institute of Civil Engineering and Building Technology, Goyang, South Korea
| | - Eunji Cha
- School of Civil, Environmental and Architectural Engineering, Korea University, Seoul, South Korea
| | - So-Young Ham
- School of Civil, Environmental and Architectural Engineering, Korea University, Seoul, South Korea
| | - Jeong-Hoon Park
- Clean Innovation Technology Group, Korea Institute of Industrial Technology, Jeju, South Korea
| | - SangJin Nam
- College of Pharmacy, Korea University, Sejong, South Korea
| | - Hongmok Kwon
- College of Pharmacy, Korea University, Sejong, South Korea
| | - Youngjoo Byun
- College of Pharmacy, Korea University, Sejong, South Korea.,Biomedical Research Center, Korea University Guro Hospital, Seoul, South Korea
| | - Hee-Deung Park
- School of Civil, Environmental and Architectural Engineering, Korea University, Seoul, South Korea.,KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, South Korea
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Zhang W, Luo Q, Zhang Y, Fan X, Ye T, Mishra S, Bhatt P, Zhang L, Chen S. Quorum Quenching in a Novel Acinetobacter sp. XN-10 Bacterial Strain against Pectobacterium carotovorum subsp. carotovorum. Microorganisms 2020; 8:microorganisms8081100. [PMID: 32717872 PMCID: PMC7466008 DOI: 10.3390/microorganisms8081100] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 07/20/2020] [Accepted: 07/21/2020] [Indexed: 01/05/2023] Open
Abstract
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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Affiliation(s)
- Wenping Zhang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou 510642, China; (W.Z.); (Q.L.); (Y.Z.); (X.F.); (T.Y.); (S.M.); (P.B.); (L.Z.)
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
| | - Qingqing Luo
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou 510642, China; (W.Z.); (Q.L.); (Y.Z.); (X.F.); (T.Y.); (S.M.); (P.B.); (L.Z.)
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
| | - Yiyin Zhang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou 510642, China; (W.Z.); (Q.L.); (Y.Z.); (X.F.); (T.Y.); (S.M.); (P.B.); (L.Z.)
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
| | - Xinghui Fan
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou 510642, China; (W.Z.); (Q.L.); (Y.Z.); (X.F.); (T.Y.); (S.M.); (P.B.); (L.Z.)
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
| | - Tian Ye
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou 510642, China; (W.Z.); (Q.L.); (Y.Z.); (X.F.); (T.Y.); (S.M.); (P.B.); (L.Z.)
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
| | - Sandhya Mishra
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou 510642, China; (W.Z.); (Q.L.); (Y.Z.); (X.F.); (T.Y.); (S.M.); (P.B.); (L.Z.)
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
| | - Pankaj Bhatt
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou 510642, China; (W.Z.); (Q.L.); (Y.Z.); (X.F.); (T.Y.); (S.M.); (P.B.); (L.Z.)
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
| | - Lianhui Zhang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou 510642, China; (W.Z.); (Q.L.); (Y.Z.); (X.F.); (T.Y.); (S.M.); (P.B.); (L.Z.)
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
| | - Shaohua Chen
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou 510642, China; (W.Z.); (Q.L.); (Y.Z.); (X.F.); (T.Y.); (S.M.); (P.B.); (L.Z.)
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
- Correspondence:
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13
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Fan X, Ye T, Li Q, Bhatt P, Zhang L, Chen S. Potential of a Quorum Quenching Bacteria Isolate Ochrobactrum intermedium D-2 Against Soft Rot Pathogen Pectobacterium carotovorum subsp. carotovorum. Front Microbiol 2020; 11:898. [PMID: 32457732 PMCID: PMC7227377 DOI: 10.3389/fmicb.2020.00898] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 04/16/2020] [Indexed: 02/05/2023] Open
Abstract
Quorum quenching (QQ) is a promising strategy for preventing and controlling quorum sensing (QS)-mediated bacterial infections. It interferes with QS by the inhibition of signal synthesis, the detection of enzyme-catalyzed degradation, and the modification of signals. N-Acyl homoserine lactones (AHLs) represent a family of widely conserved QS signals involved in the regulation of virulence factor production in many Gram-negative bacterial pathogens. In this study, AHL-degrading bacterial strains were isolated, and the most efficient one was evaluated for its potential against QS-mediated pathogens. Results showed that an AHL-degrading bacteria Ochrobactrum intermedium D-2 effectively attenuated maceration produced by the pathogen Pectobacterium carotovorum subsp. carotovorum (Pcc) on radish and potato slices. Strain D-2 exhibited a superior AHL degradation activity and efficiently degraded various AHLs, including N-hexanoyl-L-homoserine lactone (C6HSL), N-(3-oxohexanoyl)-L-homoserine lactone (3OC6HSL), N-(3-oxooctanoyl)-L-homoserine lactone (3OC8HSL), and N-(3-oxododecanoyl)-L-homoserine lactone (3OC12HSL). Analysis of the degradation products of AHL by gas chromatography-mass spectrometry led to the identification of N-cyclohexyl-propanamide and propanamide as the main intermediate products, suggesting that AHL was degraded by hydrolysis. Annotation and analysis of the whole genome sequence of strain D-2 revealed the presence of an AHL-lactonase, termed AidF. Moreover, the application of strain D-2 was able to substantially reduce the disease severity caused by Pcc on host plants. These results reveal the biochemical basis of a highly efficient AHL-degrading bacterial isolate and present the potential to attenuate Pcc virulence through QQ.
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Affiliation(s)
- Xinghui Fan
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Tian Ye
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Qiting Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Pankaj Bhatt
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Lianhui Zhang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Shaohua Chen
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
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Phenylacetyl Coenzyme A, Not Phenylacetic Acid, Attenuates CepIR-Regulated Virulence in Burkholderia cenocepacia. Appl Environ Microbiol 2019; 85:AEM.01594-19. [PMID: 31585996 DOI: 10.1128/aem.01594-19] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 09/30/2019] [Indexed: 11/20/2022] Open
Abstract
During phenylalanine catabolism, phenylacetic acid (PAA) is converted to phenylacetyl coenzyme A (PAA-CoA) by a ligase, PaaK, and then PAA-CoA is epoxidized by a multicomponent monooxygenase, PaaABCDE, before further degradation through the tricarboxylic acid (TCA) cycle. In the opportunistic pathogen Burkholderia cenocepacia, loss of paaABCDE attenuates virulence factor expression, which is under the control of the LuxIR-like quorum sensing (QS) system, CepIR. To further investigate the link between CepIR-regulated virulence and PAA catabolism, we created knockout mutants of the first step of the pathway (PAA-CoA synthesis by PaaK) and characterized them in comparison to a paaABCDE mutant using liquid chromatography-tandem mass spectrometry (LC-MS/MS) and virulence assays. We found that while loss of PaaABCDE decreased virulence, deletion of the paaK genes resulted in a more virulent phenotype than that of the wild-type strain. Deletion of either paaK or paaABCDE led to higher levels of released PAA but no differences in levels of internal accumulation compared to the wild-type level. While we found no evidence of direct cepIR downregulation by PAA-CoA or PAA, a low-virulence cepR mutant reverted to a virulent phenotype upon removal of the paaK genes. On the other hand, removal of paaABCDE in the cepR mutant did not impact its attenuated phenotype. Together, our results suggest an indirect role for PAA-CoA in suppressing B. cenocepacia CepIR-activated virulence.IMPORTANCE The opportunistic pathogen Burkholderia cenocepacia uses a chemical signal process called quorum sensing (QS) to produce virulence factors. In B. cenocepacia, QS relies on the presence of the transcriptional regulator CepR which, upon binding QS signal molecules, activates virulence. In this work, we found that even in the absence of CepR, B. cenocepacia can elicit a pathogenic response if phenylacetyl-CoA, an intermediate of the phenylacetic acid degradation pathway, is not produced. Instead, accumulation of phenylacetyl-CoA appears to attenuate pathogenicity. Therefore, we have discovered that it is possible to trigger virulence in the absence of CepR, challenging the classical view of activation of virulence by this QS mechanism. Our work provides new insight into the relationship between metabolism and virulence in opportunistic bacteria. We propose that in the event that QS signaling molecules cannot accumulate to trigger a pathogenic response, a metabolic signal can still activate virulence in B. cenocepacia.
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15
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Disruption of Quorum Sensing and Virulence in Burkholderia cenocepacia by a Structural Analogue of the cis-2-Dodecenoic Acid Signal. Appl Environ Microbiol 2019; 85:AEM.00105-19. [PMID: 30770405 DOI: 10.1128/aem.00105-19] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2019] [Accepted: 02/07/2019] [Indexed: 12/17/2022] Open
Abstract
Quorum sensing (QS) signals are widely used by bacterial pathogens to control biological functions and virulence in response to changes in cell population densities. Burkholderia cenocepacia employs a molecular mechanism in which the cis-2-dodecenoic acid (named Burkholderia diffusible signal factor [BDSF]) QS system regulates N-acyl homoserine lactone (AHL) signal production and virulence by modulating intracellular levels of cyclic diguanosine monophosphate (c-di-GMP). Thus, inhibition of BDSF signaling may offer a non-antibiotic-based therapeutic strategy against BDSF-regulated bacterial infections. In this study, we report the synthesis of small-molecule mimics of the BDSF signal and evaluate their ability to inhibit BDSF QS signaling in B. cenocepacia A novel structural analogue of BDSF, 14-Me-C16:Δ2 (cis-14-methylpentadec-2-enoic acid), was observed to inhibit BDSF production and impair BDSF-regulated phenotypes in B. cenocepacia, including motility, biofilm formation, and virulence, while it did not inhibit the growth rate of this pathogen. 14-Me-C16:Δ2 also reduced AHL signal production. Genetic and biochemical analyses showed that 14-Me-C16:Δ2 inhibited the production of the BDSF and AHL signals by decreasing the expression of their synthase-encoding genes. Notably, 14-Me-C16:Δ2 attenuated BDSF-regulated phenotypes in various Burkholderia species. These findings suggest that 14-Me-C16:Δ2 could potentially be developed as a new therapeutic agent against pathogenic Burkholderia species by interfering with their QS signaling.IMPORTANCE Burkholderia cenocepacia is an important opportunistic pathogen which can cause life-threatening infections in susceptible individuals, particularly in cystic fibrosis and immunocompromised patients. It usually employs two types of quorum sensing (QS) systems, including the cis-2-dodecenoic acid (BDSF) system and N-acyl homoserine lactone (AHL) system, to regulate virulence. In this study, we have designed and identified an unsaturated fatty acid compound (cis-14-methylpentadec-2-enoic acid [14-Me-C16:Δ2]) that is capable of interfering with B. cenocepacia QS signaling and virulence. We demonstrate that 14-Me-C16:Δ2 reduced BDSF and AHL signal production in B. cenocepacia It also impaired QS-regulated phenotypes in various Burkholderia species. These results suggest that 14-Me-C16:Δ2 could interfere with QS signaling in many Burkholderia species and might be developed as a new antibacterial agent.
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16
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Richter AM, Fazli M, Schmid N, Shilling R, Suppiger A, Givskov M, Eberl L, Tolker-Nielsen T. Key Players and Individualists of Cyclic-di-GMP Signaling in Burkholderia cenocepacia. Front Microbiol 2019; 9:3286. [PMID: 30687272 PMCID: PMC6335245 DOI: 10.3389/fmicb.2018.03286] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 12/17/2018] [Indexed: 12/19/2022] Open
Abstract
Burkholderia cenocepacia H111 is an opportunistic pathogen associated with chronic lung infections in cystic fibrosis patients. Biofilm formation, motility and virulence of B. cenocepacia are regulated by the second messenger cyclic di-guanosine monophosphate (c-di-GMP). In the present study, we analyzed the role of all 25 putative c-di-GMP metabolizing proteins of B. cenocepacia H111 with respect to motility, colony morphology, pellicle formation, biofilm formation, and virulence. We found that RpfR is a key regulator of c-di-GMP signaling in B. cenocepacia, affecting a broad spectrum of phenotypes under various environmental conditions. In addition, we identified Bcal2449 as a regulator of B. cenocepacia virulence in Galleria mellonella larvae. While Bcal2449 consists of protein domains that may catalyze both c-di-GMP synthesis and degradation, only the latter was essential for larvae killing, suggesting that a decreased c-di-GMP level mediated by the Bcal2449 protein is required for virulence of B. cenocepacia. Finally, our work suggests that some individual proteins play a role in regulating exclusively motility (CdpA), biofilm formation (Bcam1160) or both (Bcam2836).
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Affiliation(s)
- Anja M Richter
- Costerton Biofilm Center, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mustafa Fazli
- Costerton Biofilm Center, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Nadine Schmid
- Department of Microbiology, University of Zurich, Zurich, Switzerland
| | - Rebecca Shilling
- Department of Microbiology, University of Zurich, Zurich, Switzerland
| | - Angela Suppiger
- Department of Microbiology, University of Zurich, Zurich, Switzerland
| | - Michael Givskov
- Costerton Biofilm Center, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Leo Eberl
- Department of Microbiology, University of Zurich, Zurich, Switzerland
| | - Tim Tolker-Nielsen
- Costerton Biofilm Center, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Burkholderia cenocepacia integrates cis-2-dodecenoic acid and cyclic dimeric guanosine monophosphate signals to control virulence. Proc Natl Acad Sci U S A 2017; 114:13006-13011. [PMID: 29158389 DOI: 10.1073/pnas.1709048114] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Quorum sensing (QS) signals are used by bacteria to regulate biological functions in response to cell population densities. Cyclic diguanosine monophosphate (c-di-GMP) regulates cell functions in response to diverse environmental chemical and physical signals that bacteria perceive. In Burkholderia cenocepacia, the QS signal receptor RpfR degrades intracellular c-di-GMP when it senses the QS signal cis-2-dodecenoic acid, also called Burkholderia diffusible signal factor (BDSF), as a proxy for high cell density. However, it was unclear how this resulted in control of BDSF-regulated phenotypes. Here, we found that RpfR forms a complex with a regulator named GtrR (BCAL1536) to enhance its binding to target gene promoters under circumstances where the BDSF signal binds to RpfR to stimulate its c-di-GMP phosphodiesterase activity. In the absence of BDSF, c-di-GMP binds to the RpfR-GtrR complex and inhibits its ability to control gene expression. Mutations in rpfR and gtrR had overlapping effects on both the B. cenocepacia transcriptome and BDSF-regulated phenotypes, including motility, biofilm formation, and virulence. These results show that RpfR is a QS signal receptor that also functions as a c-di-GMP sensor. This protein thus allows B. cenocepacia to integrate information about its physical and chemical surroundings as well as its population density to control diverse biological functions including virulence. This type of QS system appears to be widely distributed in beta and gamma proteobacteria.
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18
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Jung HI, Kim YJ, Lee YJ, Lee HS, Lee JK, Kim SK. Mutation of the cyclic di-GMP phosphodiesterase gene in Burkholderia lata SK875 attenuates virulence and enhances biofilm formation. J Microbiol 2017; 55:800-808. [PMID: 28956352 DOI: 10.1007/s12275-017-7374-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 09/14/2017] [Accepted: 09/17/2017] [Indexed: 12/11/2022]
Abstract
Burkholderia sp. is a gram-negative bacterium that commonly exists in the environment, and can cause diseases in plants, animals, and humans. Here, a transposon mutant library of a Burkholderia lata isolate from a pig with swine respiratory disease in Korea was screened for strains showing attenuated virulence in Caenorhabditis elegans. One such mutant was obtained, and the Tn5 insertion junction was mapped to rpfR, a gene encoding a cyclic di-GMP phosphodiesterase that functions as a receptor. Mutation of rpfR caused a reduction in growth on CPG agar and swimming motility as well as a rough colony morphology on Congo red agar. TLC analysis showed reduced AHL secretion, which was in agreement with the results from plate-based and bioluminescence assays. The mutant strain produced significantly more biofilm detected by crystal violet staining than the parent strain. SEM of the mutant strain clearly showed that the overproduced biofilm contained a filamentous structure. These results suggest that the cyclic di-GMP phosphodiesterase RpfR plays an important role in quorum sensing modulation of the bacterial virulence and biofilm formation.
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Affiliation(s)
- Hae-In Jung
- Department of Animal Science and Technology, Konkuk University, Seoul, 05029, Republic of Korea
| | - Yun-Jung Kim
- Department of Animal Science and Technology, Konkuk University, Seoul, 05029, Republic of Korea
| | - Yun-Jung Lee
- Department of Animal Science and Technology, Konkuk University, Seoul, 05029, Republic of Korea
| | - Hee-Soo Lee
- National Veterinary Research and Quarantine Service, Anyang, 14033, Republic of Korea
| | - Jung-Kee Lee
- Department of Life Science and Genetic Engineering, Paichai University, Daejeon, 35345, Republic of Korea
| | - Soo-Ki Kim
- Department of Animal Science and Technology, Konkuk University, Seoul, 05029, Republic of Korea.
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Fatty acid DSF binds and allosterically activates histidine kinase RpfC of phytopathogenic bacterium Xanthomonas campestris pv. campestris to regulate quorum-sensing and virulence. PLoS Pathog 2017; 13:e1006304. [PMID: 28369120 PMCID: PMC5391125 DOI: 10.1371/journal.ppat.1006304] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 04/13/2017] [Accepted: 03/20/2017] [Indexed: 12/01/2022] Open
Abstract
As well as their importance to nutrition, fatty acids (FA) represent a unique group of quorum sensing chemicals that modulate the behavior of bacterial population in virulence. However, the way in which full-length, membrane-bound receptors biochemically detect FA remains unclear. Here, we provide genetic, enzymological and biophysical evidences to demonstrate that in the phytopathogenic bacterium Xanthomonas campestris pv. campestris, a medium-chain FA diffusible signal factor (DSF) binds directly to the N-terminal, 22 amino acid-length sensor region of a receptor histidine kinase (HK), RpfC. The binding event remarkably activates RpfC autokinase activity by causing an allosteric change associated with the dimerization and histidine phosphotransfer (DHp) and catalytic ATP-binding (CA) domains. Six residues were found essential for sensing DSF, especially those located in the region adjoining to the inner membrane of cells. Disrupting direct DSF-RpfC interaction caused deficiency in bacterial virulence and biofilm development. In addition, two amino acids within the juxtamembrane domain of RpfC, Leu172 and Ala178, are involved in the autoinhibition of the RpfC kinase activity. Replacements of them caused constitutive activation of RpfC-mediated signaling regardless of DSF stimulation. Therefore, our results revealed a biochemical mechanism whereby FA activates bacterial HK in an allosteric manner, which will assist in future studies on the specificity of FA-HK recognition during bacterial virulence regulation and cell-cell communication. Besides roles in nutrition, lipids also function as important signals in the regulation of prokaryotic and eukaryotic cells. In bacteria, fatty acids are part of the language of cell-cell communication known as quorum sensing for a decade. However, how bacteria detect these signals and regulate virulence remains elusive. Here, we provide multiple evidences to show that a full-length receptor histidine kinase, RpfC, directly binds to a fatty acid-based signal factor using a short sensor region. This binding event stimulates RpfC autokinase activity by triggering conformational change in its catalytic region, which is critical in regulating bacterial quorum sensing and virulence. Our results confirm a long-outstanding assumption in cell signaling of phytobacteria, and provide a technical pipeline to analyze fatty acid-receptor interactions.
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Zhou L, Zhang LH, Cámara M, He YW. The DSF Family of Quorum Sensing Signals: Diversity, Biosynthesis, and Turnover. Trends Microbiol 2017; 25:293-303. [DOI: 10.1016/j.tim.2016.11.013] [Citation(s) in RCA: 105] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Revised: 11/09/2016] [Accepted: 11/22/2016] [Indexed: 01/18/2023]
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21
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Yaniv K, Golberg K, Kramarsky-Winter E, Marks R, Pushkarev A, Béjà O, Kushmaro A. Functional marine metagenomic screening for anti-quorum sensing and anti-biofilm activity. BIOFOULING 2017; 33:1-13. [PMID: 27882771 DOI: 10.1080/08927014.2016.1253684] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 10/17/2016] [Indexed: 06/06/2023]
Abstract
Quorum sensing (QS), a cell-to-cell communication process, entails the production of signaling molecules that enable synchronized gene expression in microbial communities to regulate myriad microbial functions, including biofilm formation. QS disruption may constitute an innovative approach to the design of novel antifouling and anti-biofilm agents. To identify novel quorum sensing inhibitors (QSI), 2,500 environmental bacterial artificial chromosomes (BAC) from uncultured marine planktonic bacteria were screened for QSI activity using soft agar overlaid with wild type Chromobacterium violaceum as an indicator. Of the BAC library clones, 7% showed high QSI activity (>40%) against the indicator bacterium, suggesting that QSI is common in the marine environment. The most active compound, eluted from BAC clone 14-A5, disrupted QS signaling pathways and reduced biofilm formation in both Pseudomonas aeruginosa and Acinetobacter baumannii. The mass spectra of the active BAC clone (14-A5) that had been visualized by thin layer chromatography was dominated by a m/z peak of 362.1.
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Affiliation(s)
- Karin Yaniv
- a Avram and Stella Goldstein-Goren Department of Biotechnology Engineering, Faculty of Engineering Sciences , Ben-Gurion University of the Negev , Beer-Sheva , Israel
| | - Karina Golberg
- a Avram and Stella Goldstein-Goren Department of Biotechnology Engineering, Faculty of Engineering Sciences , Ben-Gurion University of the Negev , Beer-Sheva , Israel
| | - Esti Kramarsky-Winter
- a Avram and Stella Goldstein-Goren Department of Biotechnology Engineering, Faculty of Engineering Sciences , Ben-Gurion University of the Negev , Beer-Sheva , Israel
| | - Robert Marks
- a Avram and Stella Goldstein-Goren Department of Biotechnology Engineering, Faculty of Engineering Sciences , Ben-Gurion University of the Negev , Beer-Sheva , Israel
- b The Ilse Katz Center for Meso and Nanoscale Science and Technology , Ben-Gurion University of the Negev , Beer-Sheva , Israel
| | - Alina Pushkarev
- c Faculty of Biology , Technion-Israel Institute of Technology , Haifa , Israel
| | - Oded Béjà
- c Faculty of Biology , Technion-Israel Institute of Technology , Haifa , Israel
| | - Ariel Kushmaro
- a Avram and Stella Goldstein-Goren Department of Biotechnology Engineering, Faculty of Engineering Sciences , Ben-Gurion University of the Negev , Beer-Sheva , Israel
- b The Ilse Katz Center for Meso and Nanoscale Science and Technology , Ben-Gurion University of the Negev , Beer-Sheva , Israel
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Cyclic Di-GMP Regulates Multiple Cellular Functions in the Symbiotic Alphaproteobacterium Sinorhizobium meliloti. J Bacteriol 2015; 198:521-35. [PMID: 26574513 DOI: 10.1128/jb.00795-15] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2015] [Accepted: 11/09/2015] [Indexed: 12/14/2022] Open
Abstract
UNLABELLED Sinorhizobium meliloti undergoes major lifestyle changes between planktonic states, biofilm formation, and symbiosis with leguminous plant hosts. In many bacteria, the second messenger 3',5'-cyclic di-GMP (c-di-GMP, or cdG) promotes a sessile lifestyle by regulating a plethora of processes involved in biofilm formation, including motility and biosynthesis of exopolysaccharides (EPS). Here, we systematically investigated the role of cdG in S. meliloti Rm2011 encoding 22 proteins putatively associated with cdG synthesis, degradation, or binding. Single mutations in 21 of these genes did not cause evident changes in biofilm formation, motility, or EPS biosynthesis. In contrast, manipulation of cdG levels by overproducing endogenous or heterologous diguanylate cyclases (DGCs) or phosphodiesterases (PDEs) affected these processes and accumulation of N-Acyl-homoserine lactones in the culture supernatant. Specifically, individual overexpression of the S. meliloti genes pleD, SMb20523, SMb20447, SMc01464, and SMc03178 encoding putative DGCs and of SMb21517 encoding a single-domain PDE protein had an impact and resulted in increased levels of cdG. Compared to the wild type, an S. meliloti strain that did not produce detectable levels of cdG (cdG(0)) was more sensitive to acid stress. However, it was symbiotically potent, unaffected in motility, and only slightly reduced in biofilm formation. The SMc01790-SMc01796 locus, homologous to the Agrobacterium tumefaciens uppABCDEF cluster governing biosynthesis of a unipolarly localized polysaccharide, was found to be required for cdG-stimulated biofilm formation, while the single-domain PilZ protein McrA was identified as a cdG receptor protein involved in regulation of motility. IMPORTANCE We present the first systematic genome-wide investigation of the role of 3',5'-cyclic di-GMP (c-di-GMP, or cdG) in regulation of motility, biosynthesis of exopolysaccharides, biofilm formation, quorum sensing, and symbiosis in a symbiotic alpha-rhizobial species. Phenotypes of an S. meliloti strain unable to produce cdG (cdG(0)) demonstrated that this second messenger is not essential for root nodule symbiosis but may contribute to acid tolerance. Our data further suggest that enhanced levels of cdG promote sessility of S. meliloti and uncovered a single-domain PilZ protein as regulator of motility.
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Huedo P, Yero D, Martinez-Servat S, Ruyra À, Roher N, Daura X, Gibert I. Decoding the genetic and functional diversity of the DSF quorum-sensing system in Stenotrophomonas maltophilia. Front Microbiol 2015; 6:761. [PMID: 26284046 PMCID: PMC4517397 DOI: 10.3389/fmicb.2015.00761] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 07/13/2015] [Indexed: 11/13/2022] Open
Abstract
Stenotrophomonas maltophilia uses the Diffusible Signal Factor (DSF) quorum sensing (QS) system to mediate intra- and inter-specific signaling and regulate virulence-related processes. The components of this system are encoded by the rpf cluster, with genes rpfF and rpfC encoding for the DSF synthase RpfF and sensor RpfC, respectively. Recently, we have shown that there exist two variants of the rpf cluster (rpf-1 and rpf-2), distinguishing two groups of S. maltophilia strains. Surprisingly, only rpf-1 strains produce detectable DSF, correlating with their ability to control biofilm formation, swarming motility and virulence. The evolutive advantage of acquiring two different rpf clusters, the phylogenetic time point and mechanism of this acquisition and the conditions that activate DSF production in rpf-2 strains, are however not known. Examination of this cluster in various species suggests that its variability originated most probably by genetic exchange between rhizosphere bacteria. We propose that rpf-2 variant strains make use of a strategy recently termed as "social cheating." Analysis of cellular and extracellular fatty acids (FAs) of strains E77 (rpf-1) and M30 (rpf-2) suggests that their RpfFs have also a thioesterase activity that facilitates the release of unspecific FAs to the medium in addition to DSF. Production of DSF in rpf-1 strains appears in fact to be modulated by some of these extracellular FAs in addition to other factors such as temperature and nutrients, while in rpf-2 strains DSF biosynthesis is derepressed only upon detection of DSF itself, suggesting that they require cohabitation with DSF-producer bacteria to activate their DSF regulatory machinery. Finally, we show that the mixed rpf-1/rpf-2 population presents synergism in DSF production and virulence capacity in an in vivo infection model. Recovery and quantification of DSF from co-infected animals correlates with the observed mortality rate.
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Affiliation(s)
- Pol Huedo
- Institut de Biotecnologia i de Biomedicina (IBB), Universitat Autònoma de Barcelona (UAB) Barcelona, Spain ; Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona Barcelona, Spain
| | - Daniel Yero
- Institut de Biotecnologia i de Biomedicina (IBB), Universitat Autònoma de Barcelona (UAB) Barcelona, Spain ; Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona Barcelona, Spain
| | - Sònia Martinez-Servat
- Institut de Biotecnologia i de Biomedicina (IBB), Universitat Autònoma de Barcelona (UAB) Barcelona, Spain ; Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona Barcelona, Spain
| | - Àngels Ruyra
- Institut de Biotecnologia i de Biomedicina (IBB), Universitat Autònoma de Barcelona (UAB) Barcelona, Spain
| | - Nerea Roher
- Institut de Biotecnologia i de Biomedicina (IBB), Universitat Autònoma de Barcelona (UAB) Barcelona, Spain
| | - Xavier Daura
- Institut de Biotecnologia i de Biomedicina (IBB), Universitat Autònoma de Barcelona (UAB) Barcelona, Spain ; Catalan Institution for Research and Advanced Studies Barcelona, Spain
| | - Isidre Gibert
- Institut de Biotecnologia i de Biomedicina (IBB), Universitat Autònoma de Barcelona (UAB) Barcelona, Spain ; Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona Barcelona, Spain
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Martínez P, Huedo P, Martinez-Servat S, Planell R, Ferrer-Navarro M, Daura X, Yero D, Gibert I. Stenotrophomonas maltophilia responds to exogenous AHL signals through the LuxR solo SmoR (Smlt1839). Front Cell Infect Microbiol 2015; 5:41. [PMID: 26029670 PMCID: PMC4432800 DOI: 10.3389/fcimb.2015.00041] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 04/28/2015] [Indexed: 11/22/2022] Open
Abstract
Quorum Sensing (QS) mediated by Acyl Homoserine Lactone (AHL) molecules are probably the most widespread and studied among Gram-negative bacteria. Canonical AHL systems are composed by a synthase (LuxI family) and a regulator element (LuxR family), whose genes are usually adjacent in the genome. However, incomplete AHL-QS machinery lacking the synthase LuxI is frequently observed in Proteobacteria, and the regulator element is then referred as LuxR solo. It has been shown that certain LuxR solos participate in interspecific communication by detecting signals produced by different organisms. In the case of Stenotrophomonas maltophilia, a preliminary genome sequence analysis revealed numerous putative luxR genes, none of them associated to a luxI gene. From these, the hypothetical LuxR solo Smlt1839, here designated SmoR, presents a conserved AHL binding domain and a helix-turn-helix DNA binding motif. Its genomic organization—adjacent to hchA gene—indicate that SmoR belongs to the new family “LuxR regulator chaperone HchA-associated.” AHL-binding assays revealed that SmoR binds to AHLs in-vitro, at least to oxo-C8-homoserine lactone, and it regulates operon transcription, likely by recognizing a conserved palindromic regulatory box in the hchA upstream region. Supplementation with concentrated supernatants from Pseudomonas aeruginosa, which contain significant amounts of AHLs, promoted swarming motility in S. maltophilia. Contrarily, no swarming stimulation was observed when the P. aeruginosa supernatant was treated with the lactonase AiiA from Bacillus subtilis, confirming that AHL contributes to enhance the swarming ability of S. maltophilia. Finally, mutation of smoR resulted in a swarming alteration and an apparent insensitivity to the exogenous AHLs provided by P. aeruginosa. In conclusion, our results demonstrate that S. maltophilia senses AHLs produced by neighboring bacteria through the LuxR solo SmoR, regulating population behaviors such as swarming motility.
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Affiliation(s)
- Paula Martínez
- Grup de Genètica Molecular i Patogènesi Bacteriana, Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona Barcelona, Spain ; Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona Barcelona, Spain
| | - Pol Huedo
- Grup de Genètica Molecular i Patogènesi Bacteriana, Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona Barcelona, Spain ; Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona Barcelona, Spain
| | - Sònia Martinez-Servat
- Grup de Genètica Molecular i Patogènesi Bacteriana, Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona Barcelona, Spain ; Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona Barcelona, Spain
| | - Raquel Planell
- Grup de Genètica Molecular i Patogènesi Bacteriana, Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona Barcelona, Spain
| | - Mario Ferrer-Navarro
- Grup de Genètica Molecular i Patogènesi Bacteriana, Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona Barcelona, Spain
| | - Xavier Daura
- Grup de Genètica Molecular i Patogènesi Bacteriana, Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona Barcelona, Spain ; Catalan Institution for Research and Advanced Studies Barcelona, Spain
| | - Daniel Yero
- Grup de Genètica Molecular i Patogènesi Bacteriana, Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona Barcelona, Spain ; Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona Barcelona, Spain
| | - Isidre Gibert
- Grup de Genètica Molecular i Patogènesi Bacteriana, Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona Barcelona, Spain ; Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona Barcelona, Spain
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[Networks involving quorum sensing, cyclic-di-GMP and nitric oxide on biofilm production in bacteria]. Rev Argent Microbiol 2014; 46:242-55. [PMID: 25444134 DOI: 10.1016/s0325-7541(14)70079-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 06/03/2014] [Indexed: 01/06/2023] Open
Abstract
Bacterial biofilms are ubiquitous in nature, and their flexibility is derived in part from a complex extracellular matrix that can be made-to-order to cope with environmental demand. Although common developmental stages leading to biofilm formation have been described, an in-depth knowledge of genetic and signaling is required to understand biofilm formation. Bacteria detect changes in population density by quorum sensing and particular environmental conditions, using signals such as cyclic di-GMP or nitric oxide. The significance of understanding these signaling pathways lies in that they control a broad variety of functions such as biofilm formation, and motility, providing benefits to bacteria as regards host colonization, defense against competitors, and adaptation to changing environments. Due to the importance of these features, we here review the signaling network and regulatory connections among quorum sensing, c-di-GMP and nitric oxide involving biofilm formation.
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Fazli M, Almblad H, Rybtke ML, Givskov M, Eberl L, Tolker-Nielsen T. Regulation of biofilm formation in Pseudomonas and Burkholderia species. Environ Microbiol 2014; 16:1961-81. [PMID: 24592823 DOI: 10.1111/1462-2920.12448] [Citation(s) in RCA: 185] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 02/12/2014] [Accepted: 02/28/2014] [Indexed: 01/28/2023]
Abstract
In the present review, we describe and compare the molecular mechanisms that are involved in the regulation of biofilm formation by Pseudomonas putida, Pseudomonas fluorescens, Pseudomonas aeruginosa and Burkholderia cenocepacia. Our current knowledge suggests that biofilm formation is regulated by cyclic diguanosine-5'-monophosphate (c-di-GMP), small RNAs (sRNA) and quorum sensing (QS) in all these bacterial species. The systems that employ c-di-GMP as a second messenger regulate the production of exopolysaccharides and surface proteins which function as extracellular matrix components in the biofilms formed by the bacteria. The systems that make use of sRNAs appear to regulate the production of exopolysaccharide biofilm matrix material in all these species. In the pseudomonads, QS regulates the production of extracellular DNA, lectins and biosurfactants which all play a role in biofilm formation. In B.cenocepacia QS regulates the expression of a large surface protein, lectins and extracellular DNA that all function as biofilm matrix components. Although the three regulatory systems all regulate the production of factors used for biofilm formation, the molecular mechanisms involved in transducing the signals into expression of the biofilm matrix components differ between the species. Under the conditions tested, exopolysaccharides appears to be the most important biofilm matrix components for P.aeruginosa, whereas large surface proteins appear to be the most important biofilm matrix components for P.putida, P.fluorescens, and B.cenocepacia.
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Affiliation(s)
- Mustafa Fazli
- Department of International Health, Immunology, and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Department of Biology, Faculty of Science, University of Copenhagen, Copenhagen, Denmark; Department of Genetics and Bioengineering, Faculty of Engineering and Architecture, Yeditepe University, Istanbul, Turkey
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Deng Y, Boon C, Chen S, Lim A, Zhang LH. Cis-2-dodecenoic acid signal modulates virulence of Pseudomonas aeruginosa through interference with quorum sensing systems and T3SS. BMC Microbiol 2013; 13:231. [PMID: 24134835 PMCID: PMC4016476 DOI: 10.1186/1471-2180-13-231] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 10/15/2013] [Indexed: 12/23/2022] Open
Abstract
Background Cis-2-dodecenoic acid (BDSF) is well known for its important functions in intraspecies signaling in Burkholderia cenocepacia. Previous work has also established an important role of BDSF in interspecies and inter-kingdom communications. It was identified that BDSF modulates virulence of Pseudomonas aeruginosa. However, how BDSF interferes with virulence of P. aeruginosa is still not clear. Results We report here that BDSF mediates the cross-talk between B. cenocepacia and P. aeruginosa through interference with quorum sensing (QS) systems and type III secretion system (T3SS) of P. aeruginosa. Bioassay results revealed that exogenous addition of BDSF not only reduced the transcriptional expression of the regulator encoding gene of QS systems, i.e., lasR, pqsR, and rhlR, but also simultaneously decreased the production of QS signals including 3-oxo-C12-HSL, Pseudomonas quinolone signal (PQS) and C4-HSL, consequently resulting in the down-regulation of biofilm formation and virulence factor production of P. aeruginosa. Furthermore, BDSF and some of its derivatives are also capable of inhibiting T3SS of P. aeruginosa at a micromolar level. Treatment with BDSF obviously reduced the virulence of P. aeruginosa in both HeLa cell and zebrafish infection models. Conclusions These results depict that BDSF modulates virulence of P. aeruginosa through interference with QS systems and T3SS.
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Affiliation(s)
- Yinyue Deng
- Institute of Molecular and Cell Biology, Proteos, 61 Biopolis Drive, Singapore, 138673, Singapore.
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