51
|
RNA-seq-based transcriptomic analysis of AHL-induced biofilm and pyocyanin inhibition in Pseudomonas aeruginosa by Lactobacillus brevis. Int Microbiol 2022; 25:447-456. [DOI: 10.1007/s10123-021-00228-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 11/28/2021] [Accepted: 12/12/2021] [Indexed: 11/26/2022]
|
52
|
The nutritional environment is sufficient to select coexisting biofilm and quorum-sensing mutants of Pseudomonas aeruginosa. J Bacteriol 2022; 204:e0044421. [PMID: 34978461 DOI: 10.1128/jb.00444-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The evolution of bacterial populations during infections can be influenced by various factors including available nutrients, the immune system, and competing microbes, rendering it difficult to identify the specific forces that select on evolved traits. The genomes of Pseudomonas aeruginosa isolated from the airway of patients with cystic fibrosis (CF), for example, have revealed commonly mutated genes, but which phenotypes led to their prevalence is often uncertain. Here, we focus on effects of nutritional components of the CF airway on genetic adaptations by P. aeruginosa grown in either well-mixed (planktonic) or biofilm-associated conditions. After only 80 generations of experimental evolution in a simple medium with glucose, lactate, and amino acids, all planktonic populations diversified into lineages with mutated genes common to CF infections: morA, encoding a regulator of biofilm formation, or lasR, encoding a quorum sensing regulator that modulates the expression of virulence factors. Although mutated quorum sensing is often thought to be selected in vivo due to altered virulence phenotypes or social cheating, isolates with lasR mutations demonstrated increased fitness when grown alone and outcompeted the ancestral PA14 strain. Nonsynonymous SNPs in morA increased fitness in a nutrient concentration-dependent manner during planktonic growth and surprisingly also increased biofilm production. Populations propagated in biofilm conditions also acquired mutations in loci associated with chronic infections, including lasR and cyclic-di-GMP regulators roeA and wspF. These findings demonstrate that nutrient conditions and biofilm selection are sufficient to select mutants with problematic clinical phenotypes including increased biofilm and altered quorum sensing. Importance Pseudomonas aeruginosa produces dangerous chronic infections that are known for their rapid diversification and recalcitrance to treatment. We performed evolution experiments to identify adaptations selected by two specific aspects of the CF respiratory environment: nutrient levels and surface attachment. Propagation of P. aeruginosa in nutrients present within the CF airway was sufficient to drive diversification into subpopulations with identical mutations in regulators of biofilm and quorum sensing to those arising during infection. Thus, the adaptation of opportunistic pathogens to nutrients found in the host may select mutants with phenotypes that complicate treatment and clearance of infection.
Collapse
|
53
|
Miranda SW, Asfahl KL, Dandekar AA, Greenberg EP. Pseudomonas aeruginosa Quorum Sensing. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1386:95-115. [PMID: 36258070 PMCID: PMC9942581 DOI: 10.1007/978-3-031-08491-1_4] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
Pseudomonas aeruginosa, like many bacteria, uses chemical signals to communicate between cells in a process called quorum sensing (QS). QS allows groups of bacteria to sense population density and, in response to changing cell densities, to coordinate behaviors. The P. aeruginosa QS system consists of two complete circuits that involve acyl-homoserine lactone signals and a third system that uses quinolone signals. Together, these three QS circuits regulate the expression of hundreds of genes, many of which code for virulence factors. P. aeruginosa has become a model for studying the molecular biology of QS and the ecology and evolution of group behaviors in bacteria. In this chapter, we recount the history of discovery of QS systems in P. aeruginosa, discuss how QS relates to virulence and the ecology of this bacterium, and explore strategies to inhibit QS. Finally, we discuss future directions for research in P. aeruginosa QS.
Collapse
Affiliation(s)
| | - Kyle L Asfahl
- Department of Microbiology, University of Washington School of Medicine, Seattle, WA, USA
| | - Ajai A Dandekar
- Department of Microbiology, University of Washington School of Medicine, Seattle, WA, USA
- Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA
| | - E P Greenberg
- Department of Microbiology, University of Washington School of Medicine, Seattle, WA, USA.
| |
Collapse
|
54
|
Chadha J, Harjai K, Chhibber S. Repurposing phytochemicals as anti-virulent agents to attenuate quorum sensing-regulated virulence factors and biofilm formation in Pseudomonas aeruginosa. Microb Biotechnol 2021; 15:1695-1718. [PMID: 34843159 PMCID: PMC9151347 DOI: 10.1111/1751-7915.13981] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Accepted: 11/14/2021] [Indexed: 12/18/2022] Open
Abstract
Unregulated consumption and overexploitation of antibiotics have paved the way for emergence of antibiotic‐resistant strains and ‘superbugs’. Pseudomonas aeruginosa is among the opportunistic nosocomial pathogens causing devastating infections in clinical set‐ups globally. Its artillery equipped with diversified virulence elements, extensive antibiotic resistance and biofilms has made it a ‘hard‐to‐treat’ pathogen. The pathogenicity of P. aeruginosa is modulated by an intricate cell density‐dependent mechanism called quorum sensing (QS). The virulence artillery of P. aeruginosa is firmly controlled by QS genes, and their expression drives the aggressiveness of the infection. Attempts to identify and develop novel antimicrobials have seen a sharp rise in the past decade. Among different proposed mechanisms, a novel anti‐virulence approach to target pseudomonal infections by virtue of anti‐QS and anti‐biofilm drugs appears to occupy the centre stage. In this respect, bioactive phytochemicals have gained prominence among the scientific community owing to their significant quorum quenching (QQ) properties. Recent studies have shed light on the QQ activities of various phytochemicals and other drugs in perturbing the QS‐dependent virulence in P. aeruginosa. This review highlights the recent evidences that reinforce the application of plant bioactives for combating pseudomonal infections, their advantages and shortcomings in anti‐virulence therapy.
Collapse
Affiliation(s)
- Jatin Chadha
- Department of Microbiology, Panjab University, Chandigarh, India
| | - Kusum Harjai
- Department of Microbiology, Panjab University, Chandigarh, India
| | - Sanjay Chhibber
- Department of Microbiology, Panjab University, Chandigarh, India
| |
Collapse
|
55
|
Plasmids do not consistently stabilize cooperation across bacteria but may promote broad pathogen host-range. Nat Ecol Evol 2021; 5:1624-1636. [PMID: 34750532 PMCID: PMC7612097 DOI: 10.1038/s41559-021-01573-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 09/27/2021] [Indexed: 11/24/2022]
Abstract
Horizontal gene transfer via plasmids could favour cooperation in bacteria, because transfer of a cooperative gene turns non-cooperative cheats into cooperators. This hypothesis has received support from theoretical, genomic and experimental analyses. In contrast, we show here, with a comparative analysis across 51 diverse species, that genes for extracellular proteins, which are likely to act as cooperative ‘public goods’, were not more likely to be carried on either: (i) plasmids compared to chromosomes; or (ii) plasmids that transfer at higher rates. Our results were supported by theoretical modelling which showed that while horizontal gene transfer can help cooperative genes initially invade a population, it has less influence on the longer-term maintenance of cooperation. Instead, we found that genes for extracellular proteins were more likely to be on plasmids when they coded for pathogenic virulence traits, in pathogenic bacteria with a broad host-range.
Collapse
|
56
|
Groleau MC, Taillefer H, Vincent AT, Constant P, Déziel E. Pseudomonas aeruginosa isolates defective in function of the LasR quorum sensing regulator are frequent in diverse environmental niches. Environ Microbiol 2021; 24:1062-1075. [PMID: 34488244 DOI: 10.1111/1462-2920.15745] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 08/24/2021] [Indexed: 01/12/2023]
Abstract
The saprophyte Pseudomonas aeruginosa is a versatile opportunistic pathogen causing infections in immunocompromised individuals. To facilitate its adaptation to a large variety of niches, this bacterium exploits population density-dependent gene regulation systems called quorum sensing (QS). In P. aeruginosa, three distinct but interrelated QS systems (las, rhl and pqs) regulate the production of many survival and virulence functions. In prototypical strains, the las system, through its transcriptional regulator LasR, is important for the full activation of the rhl and pqs systems. Still, LasR-deficient isolates have been reported, mostly sampled from the lungs of people with cystic fibrosis, where they are considered selected by the chronic infection environment. In this study, we show that a defect in LasR activity appears to be an actually widespread mechanism of adaptation in this bacterium. Indeed, we found abundant LasR-defective isolates sampled from hydrocarbon-contaminated soils, hospital sink drains and meat/fish market environments, using an approach based on phenotypic profiling, supported by gene sequencing. Interestingly, several LasR-defective isolates maintain an active rhl system or are deficient in pqs system signalling. The high prevalence of a LasR-defective phenotype among environmental P. aeruginosa isolates questions the role of QS in niche adaptation.
Collapse
Affiliation(s)
- Marie-Christine Groleau
- Centre Armand-Frappier Santé Biotechnologie, Institut national de la recherche scientifique (INRS), Laval, Quebec, Canada
| | - Hélène Taillefer
- Centre Armand-Frappier Santé Biotechnologie, Institut national de la recherche scientifique (INRS), Laval, Quebec, Canada
| | - Antony T Vincent
- Département des sciences animales, Faculté des sciences de l'agriculture et de l'alimentation, Université Laval, Quebec City, Quebec, Canada
| | - Philippe Constant
- Centre Armand-Frappier Santé Biotechnologie, Institut national de la recherche scientifique (INRS), Laval, Quebec, Canada
| | - Eric Déziel
- Centre Armand-Frappier Santé Biotechnologie, Institut national de la recherche scientifique (INRS), Laval, Quebec, Canada
| |
Collapse
|
57
|
Cell Growth Model with Stochastic Gene Expression Helps Understand the Growth Advantage of Metabolic Exchange and Auxotrophy. mSystems 2021; 6:e0044821. [PMID: 34342540 PMCID: PMC8407474 DOI: 10.1128/msystems.00448-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
During cooperative growth, microbes often experience higher fitness by sharing resources via metabolite exchange. How competitive species evolve to cooperate is, however, not known. Moreover, existing models (based on optimization of steady-state resources or fluxes) are often unable to explain the growth advantage for the cooperating species, even for simple reciprocally cross-feeding auxotrophic pairs. We present here an abstract model of cell growth that considers the stochastic burst-like gene expression of biosynthetic pathways of limiting biomass precursor metabolites and directly connect the amount of metabolite produced to cell growth and division, using a "metabolic sizer/adder" rule. Our model recapitulates Monod's law and yields the experimentally observed right-skewed long-tailed distribution of cell doubling times. The model further predicts the growth effect of secretion and uptake of metabolites by linking it to changes in the internal metabolite levels. The model also explains why auxotrophs may grow faster when supplied with the metabolite they cannot produce and why two reciprocally cross-feeding auxotrophs can grow faster than prototrophs. Overall, our framework allows us to predict the growth effect of metabolic interactions in independent microbes and microbial communities, setting up the stage to study the evolution of these interactions. IMPORTANCE Cooperative behaviors are highly prevalent in the wild, but their evolution is not understood. Metabolic flux models can demonstrate the viability of metabolic exchange as cooperative interactions, but steady-state growth models cannot explain why cooperators grow faster. We present a stochastic model that connects growth to the cell's internal metabolite levels and quantifies the growth effect of metabolite exchange and auxotrophy. We show that a reduction in gene expression noise can explain why cells that import metabolites or become auxotrophs can grow faster and why reciprocal cross-feeding of metabolites between complementary auxotrophs allows them to grow faster. Furthermore, our framework can simulate the growth of interacting cells, which will enable us to understand the possible trajectories of the evolution of cooperation in silico.
Collapse
|
58
|
Wu S, Xue Y, Yang S, Xu C, Liu C, Liu X, Liu J, Zhu H, Zhao GR, Yang A, Qiao J. Combinational quorum sensing devices for dynamic control in cross-feeding cocultivation. Metab Eng 2021; 67:186-197. [PMID: 34229080 DOI: 10.1016/j.ymben.2021.07.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 05/26/2021] [Accepted: 07/02/2021] [Indexed: 10/20/2022]
Abstract
Quorum sensing (QS) offers cell density dependent dynamic regulations in cell culture through devices such as synchronized lysis circuit (SLC) and metabolic toggle switch (MTS). However, there is still a lack of studies on cocultivation with a combination of different QS-based devices. Taking the production of isopropanol and salidroside as case studies, we have mathematically modeled a comprehensive set of QS-regulated cocultivation schemes and constructed experimental combinations of QS devices, respectively, to evaluate their feasibility and optimality for regulating growth competition and corporative production. Glucose split ratio is proposed for the analysis of competition between cell growth and targeted production. Results show that the combination of different QS devices across multiple members offers a new tool with the potential to effectively coordinate synthetic microbial consortia for achieving high product titer in cross-feeding cocultivation. It is also evident that the performance of such systems is significantly affected by dynamic characteristics of chosen QS devices, carbon source control and the operational settings. This study offers insights for future applications of combinational QS devices in synthetic microbial consortia.
Collapse
Affiliation(s)
- Shengbo Wu
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China; State Key Laboratory of Chemical Engineering, Tianjin University, Tianjin, 300072, China
| | - Yanting Xue
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Shujuan Yang
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Chengyang Xu
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Chunjiang Liu
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China; State Key Laboratory of Chemical Engineering, Tianjin University, Tianjin, 300072, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, 300072, China
| | - Xue Liu
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China; Key Laboratory of Systems Bioengineering, Ministry of Education (Tianjin University), Tianjin, 300072, China; Frontiers Science Center for Synthetic Biology (Ministry of Education), Tianjin University, Tianjin, 300072, China
| | - Jiaheng Liu
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China; Key Laboratory of Systems Bioengineering, Ministry of Education (Tianjin University), Tianjin, 300072, China; Frontiers Science Center for Synthetic Biology (Ministry of Education), Tianjin University, Tianjin, 300072, China
| | - Hongji Zhu
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China; Key Laboratory of Systems Bioengineering, Ministry of Education (Tianjin University), Tianjin, 300072, China; Frontiers Science Center for Synthetic Biology (Ministry of Education), Tianjin University, Tianjin, 300072, China
| | - Guang-Rong Zhao
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, 300072, China; Key Laboratory of Systems Bioengineering, Ministry of Education (Tianjin University), Tianjin, 300072, China; Frontiers Science Center for Synthetic Biology (Ministry of Education), Tianjin University, Tianjin, 300072, China
| | - Aidong Yang
- Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, UK.
| | - Jianjun Qiao
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, 300072, China; Key Laboratory of Systems Bioengineering, Ministry of Education (Tianjin University), Tianjin, 300072, China; Frontiers Science Center for Synthetic Biology (Ministry of Education), Tianjin University, Tianjin, 300072, China.
| |
Collapse
|
59
|
Friends or Foes-Microbial Interactions in Nature. BIOLOGY 2021; 10:biology10060496. [PMID: 34199553 PMCID: PMC8229319 DOI: 10.3390/biology10060496] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 05/27/2021] [Accepted: 05/31/2021] [Indexed: 12/16/2022]
Abstract
Simple Summary Microorganisms like bacteria, archaea, fungi, microalgae, and viruses mostly form complex interactive networks within the ecosystem rather than existing as single planktonic cells. Interactions among microorganisms occur between the same species, with different species, or even among entirely different genera, families, or even domains. These interactions occur after environmental sensing, followed by converting those signals to molecular and genetic information, including many mechanisms and classes of molecules. Comprehensive studies on microbial interactions disclose key strategies of microbes to colonize and establish in a variety of different environments. Knowledge of the mechanisms involved in the microbial interactions is essential to understand the ecological impact of microbes and the development of dysbioses. It might be the key to exploit strategies and specific agents against different facing challenges, such as chronic and infectious diseases, hunger crisis, pollution, and sustainability. Abstract Microorganisms are present in nearly every niche on Earth and mainly do not exist solely but form communities of single or mixed species. Within such microbial populations and between the microbes and a eukaryotic host, various microbial interactions take place in an ever-changing environment. Those microbial interactions are crucial for a successful establishment and maintenance of a microbial population. The basic unit of interaction is the gene expression of each organism in this community in response to biotic or abiotic stimuli. Differential gene expression is responsible for producing exchangeable molecules involved in the interactions, ultimately leading to community behavior. Cooperative and competitive interactions within bacterial communities and between the associated bacteria and the host are the focus of this review, emphasizing microbial cell–cell communication (quorum sensing). Further, metagenomics is discussed as a helpful tool to analyze the complex genomic information of microbial communities and the functional role of different microbes within a community and to identify novel biomolecules for biotechnological applications.
Collapse
|
60
|
Tobramycin Adaptation Enhances Policing of Social Cheaters in Pseudomonas aeruginosa. Appl Environ Microbiol 2021; 87:e0002921. [PMID: 33837019 DOI: 10.1128/aem.00029-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The Pseudomonas aeruginosa LasR-LasI (LasR-I) quorum sensing system regulates secreted proteases that can be exploited by cheaters, such as quorum sensing receptor-defective (lasR) mutants. lasR mutants emerge in populations growing on casein as a sole source of carbon and energy. These mutants are exploitative cheaters because they avoid the substantial cost of engaging in quorum sensing. Previous studies showed that quorum sensing increases resistance to some antibiotics, such as tobramycin. Here, we show that tobramycin suppressed the emergence of lasR mutants in casein-passaged populations. Several mutations accumulated in those populations, indicating evidence of antibiotic adaptation. We found that mutations in one gene, ptsP, increased antibiotic resistance and also pleiotropically increased production of a quorum sensing-controlled phenazine, pyocyanin. When passaged on casein, ptsP mutants suppressed cheaters in a manner that was tobramycin independent. We found that the mechanism of cheater suppression in ptsP mutants relied on pyocyanin, which acts as a policing toxin by selectively blocking growth of cheaters. Thus, tobramycin suppresses lasR mutants through two mechanisms: first, through direct effects on cheaters and, second, by selecting mutations in ptsP that suppressed cheating in a tobramycin-independent manner. This work demonstrates how adaptive mutations can alter the dynamics of cooperator-cheater relationships, which might be important for populations adapting to antibiotics during interspecies competition or infections. IMPORTANCE The opportunistic pathogen Pseudomonas aeruginosa is a model for understanding quorum sensing, a type of cell-cell signaling important for cooperation. Quorum sensing controls production of cooperative goods, such as exoenzymes, which are vulnerable to cheating by quorum sensing-defective mutants. Because uncontrolled cheating can ultimately cause a population to collapse, much focus has been on understanding how P. aeruginosa can control cheaters. We show that an antibiotic, tobramycin, can suppress cheaters in cooperating P. aeruginosa populations. Tobramycin suppresses cheaters directly because the cheaters are more susceptible to tobramycin than cooperators. Tobramycin also selects for mutations in a gene, ptsP, that suppresses cheaters independent of tobramycin through pleiotropic regulation of a policing toxin, pyocyanin. This work supports the idea that adaptation to antibiotics can have unexpected effects on the evolution of quorum sensing and has implications for understanding how cooperation evolves in dynamic bacterial communities.
Collapse
|
61
|
Wu S, Xu C, Liu J, Liu C, Qiao J. Vertical and horizontal quorum-sensing-based multicellular communications. Trends Microbiol 2021; 29:1130-1142. [PMID: 34020859 DOI: 10.1016/j.tim.2021.04.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 04/22/2021] [Accepted: 04/26/2021] [Indexed: 12/11/2022]
Abstract
Quorum sensing (QS) plays an important role in both natural and synthetic microbial systems. The complexity of QS entails multilayer controls, biomolecular crosstalk, and population-based interactions. In this review, we divide complex QS-based interactions into vertical and horizontal interactions. With respect to the former, we discuss QS-based interactions among phages, bacteria, and hosts in natural microbial systems, which are based on various QS signals and hormones. With regard to the latter, we highlight manipulations of QS-based interactions for multicomponent synthetic microbial consortia. We further present the recent and emerging applications of manipulating these interactions (collectively referred to as 'QS communication networks') in natural and synthetic microbiota. Finally, we identify key challenges in engineering diverse QS communication networks for various future applications.
Collapse
Affiliation(s)
- Shengbo Wu
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China; State Key Laboratory of Chemical Engineering, Tianjin University, Tianjin 300072, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, 300072, China
| | - Chengyang Xu
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, 300072, China; Key Laboratory of Systems Bioengineering, Ministry of Education (Tianjin University), Tianjin, 300072, China
| | - Jiaheng Liu
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, 300072, China; Key Laboratory of Systems Bioengineering, Ministry of Education (Tianjin University), Tianjin, 300072, China
| | - Chunjiang Liu
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China; State Key Laboratory of Chemical Engineering, Tianjin University, Tianjin 300072, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, 300072, China.
| | - Jianjun Qiao
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, 300072, China; Key Laboratory of Systems Bioengineering, Ministry of Education (Tianjin University), Tianjin, 300072, China.
| |
Collapse
|
62
|
Leroy AG, Caillon J, Caroff N, Broquet A, Corvec S, Asehnoune K, Roquilly A, Crémet L. Could Azithromycin Be Part of Pseudomonas aeruginosa Acute Pneumonia Treatment? Front Microbiol 2021; 12:642541. [PMID: 33796090 PMCID: PMC8008145 DOI: 10.3389/fmicb.2021.642541] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 02/26/2021] [Indexed: 12/29/2022] Open
Abstract
Azithromycin (AZM) is a 15-membered-ring macrolide that presents a broad-spectrum antimicrobial activity against Gram-positive bacteria and atypical microorganisms but suffers from a poor diffusion across the outer-membrane of Gram-negative bacilli, including Pseudomonas aeruginosa (PA). However, AZM has demonstrated clinical benefits in patients suffering from chronic PA respiratory infections, especially cystic fibrosis patients. Since the rise of multidrug-resistant PA has led to a growing need for new therapeutic options, this macrolide has been proposed as an adjunctive therapy. Clinical trials assessing AZM in PA acute pneumonia are scarce. However, a careful examination of the available literature provides good rationales for its use in that context. In fact, 14- and 15-membered-ring macrolides have demonstrated immunomodulatory and immunosuppressive effects that could be of major interest in the management of acute illness. Furthermore, growing evidence supports a downregulation of PA virulence dependent on direct interaction with the ribosomes, and based on the modulation of several key regulators from the Quorum Sensing network. First highlighted in vitro, these interesting properties of AZM have subsequently been confirmed in the animal models. In this review, we systematically analyzed the literature regarding AZM immunomodulatory and anti-PA effects. In vitro and in vivo studies, as well as clinical trials were reviewed, looking for rationales for AZM use in PA acute pneumonia.
Collapse
Affiliation(s)
- Anne-Gaëlle Leroy
- Laboratoire EA 3826 "Thérapeutiques cliniques et expérimentales des infections", IRS2-Nantes Biotech, Université de Nantes, Nantes, France.,CHU de Nantes, Service de Bactériologie-Hygiène hospitalière, Nantes Université, Nantes, France
| | - Jocelyne Caillon
- Laboratoire EA 3826 "Thérapeutiques cliniques et expérimentales des infections", IRS2-Nantes Biotech, Université de Nantes, Nantes, France.,CHU de Nantes, Service de Bactériologie-Hygiène hospitalière, Nantes Université, Nantes, France
| | - Nathalie Caroff
- Laboratoire EA 3826 "Thérapeutiques cliniques et expérimentales des infections", IRS2-Nantes Biotech, Université de Nantes, Nantes, France
| | - Alexis Broquet
- Laboratoire EA 3826 "Thérapeutiques cliniques et expérimentales des infections", IRS2-Nantes Biotech, Université de Nantes, Nantes, France
| | - Stéphane Corvec
- CHU de Nantes, Service de Bactériologie-Hygiène hospitalière, Nantes Université, Nantes, France.,CRCINA, U1232, CHU Nantes, Nantes, France
| | - Karim Asehnoune
- Laboratoire EA 3826 "Thérapeutiques cliniques et expérimentales des infections", IRS2-Nantes Biotech, Université de Nantes, Nantes, France.,CHU de Nantes, Service Anesthésie Réanimation Chirurgicale, Nantes Université, Nantes, France
| | - Antoine Roquilly
- Laboratoire EA 3826 "Thérapeutiques cliniques et expérimentales des infections", IRS2-Nantes Biotech, Université de Nantes, Nantes, France.,CHU de Nantes, Service Anesthésie Réanimation Chirurgicale, Nantes Université, Nantes, France
| | - Lise Crémet
- Laboratoire EA 3826 "Thérapeutiques cliniques et expérimentales des infections", IRS2-Nantes Biotech, Université de Nantes, Nantes, France.,CHU de Nantes, Service de Bactériologie-Hygiène hospitalière, Nantes Université, Nantes, France
| |
Collapse
|
63
|
Bruger EL, Snyder DJ, Cooper VS, Waters CM. Quorum sensing provides a molecular mechanism for evolution to tune and maintain investment in cooperation. THE ISME JOURNAL 2021; 15:1236-1247. [PMID: 33342998 PMCID: PMC8115533 DOI: 10.1038/s41396-020-00847-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 10/22/2020] [Accepted: 11/16/2020] [Indexed: 01/29/2023]
Abstract
As selection frequently favors noncooperating defectors in mixed populations with cooperators, mechanisms that promote cooperation stability clearly exist. One potential mechanism is bacterial cell-to-cell communication, quorum sensing (QS), which can allow cooperators to prevent invasion by defectors. However, the impact of QS on widespread maintenance of cooperation in well-mixed conditions has not been experimentally demonstrated over extended evolutionary timescales. Here, we use wild-type (WT) Vibrio campbellii that regulates cooperation with QS and an unconditional cooperating (UC) mutant to examine the evolutionary origins and dynamics of novel defectors during a long-term evolution experiment. We found that UC lineages were completely outcompeted by defectors, whereas functioning QS enabled the maintenance of cooperative variants in most WT populations. Sequencing evolved populations revealed multiple luxR mutations that swept the UC lineages. However, the evolution of mutant lineages with reduced levels of bioluminescence (dims) occurred in many WT lineages. These dim variants also decreased other cooperative phenotypes regulated by QS, including protease production, indicating they result from changes to QS regulation. This diminished investment phenotype optimizes a tradeoff between cooperative input and growth output and suggests that decreasing the cost of QS could be a favorable strategy for maintaining the cooperative behaviors it regulates.
Collapse
Affiliation(s)
- Eric L. Bruger
- grid.266456.50000 0001 2284 9900Department of Biological Sciences, University of Idaho, Moscow, ID USA ,grid.266456.50000 0001 2284 9900Institute for Modeling Collaboration and Innovation, University of Idaho, Moscow, ID USA ,grid.266456.50000 0001 2284 9900Institute for Bioinformatics and Evolutionary Studies, University of Idaho, Moscow, ID USA ,grid.17088.360000 0001 2150 1785The BEACON Center for the Study of Evolution in Action, Michigan State University, East Lansing, MI USA
| | - Daniel J. Snyder
- grid.21925.3d0000 0004 1936 9000Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA USA
| | - Vaughn S. Cooper
- grid.21925.3d0000 0004 1936 9000Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA USA
| | - Christopher M. Waters
- grid.17088.360000 0001 2150 1785The BEACON Center for the Study of Evolution in Action, Michigan State University, East Lansing, MI USA ,grid.17088.360000 0001 2150 1785Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI USA
| |
Collapse
|
64
|
LasR-deficient Pseudomonas aeruginosa variants increase airway epithelial mICAM-1 expression and enhance neutrophilic lung inflammation. PLoS Pathog 2021; 17:e1009375. [PMID: 33690714 PMCID: PMC7984618 DOI: 10.1371/journal.ppat.1009375] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 03/22/2021] [Accepted: 02/13/2021] [Indexed: 11/19/2022] Open
Abstract
Pseudomonas aeruginosa causes chronic airway infections, a major determinant of lung inflammation and damage in cystic fibrosis (CF). Loss-of-function lasR mutants commonly arise during chronic CF infections, are associated with accelerated lung function decline in CF patients and induce exaggerated neutrophilic inflammation in model systems. In this study, we investigated how lasR mutants modulate airway epithelial membrane bound ICAM-1 (mICAM-1), a surface adhesion molecule, and determined its impact on neutrophilic inflammation in vitro and in vivo. We demonstrated that LasR-deficient strains induce increased mICAM-1 levels in airway epithelial cells compared to wild-type strains, an effect attributable to the loss of mICAM-1 degradation by LasR-regulated proteases and associated with enhanced neutrophil adhesion. In a subacute airway infection model, we also observed that lasR mutant-infected mice displayed greater airway epithelial ICAM-1 expression and increased neutrophilic pulmonary inflammation. Our findings provide new insights into the intricate interplay between lasR mutants, LasR-regulated proteases and airway epithelial ICAM-1 expression, and reveal a new mechanism involved in the exaggerated inflammatory response induced by lasR mutants.
Collapse
|
65
|
Iron limitation by transferrin promotes simultaneous cheating of pyoverdine and exoprotease in Pseudomonas aeruginosa. ISME JOURNAL 2021; 15:2379-2389. [PMID: 33654265 DOI: 10.1038/s41396-021-00938-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 01/29/2021] [Accepted: 02/11/2021] [Indexed: 11/09/2022]
Abstract
Pseudomonas aeruginosa is a primary bacterial model to study cooperative behaviors because it yields exoproducts such as siderophores and exoproteases that act as public goods and can be exploited by selfish nonproducers behaving as social cheaters. Iron-limited growth medium, mainly casamino acids medium supplemented with transferrin, is typically used to isolate and study nonproducer mutants of the siderophore pyoverdine. However, using a protein as the iron chelator could inadvertently select mutants unable to produce exoproteases, since these enzymes can degrade the transferrin to facilitate iron release. Here we investigated the evolutionary dynamics of pyoverdine and exoprotease production in media in which iron was limited by using either transferrin or a cation chelating resin. We show that concomitant loss of pyoverdine and exoprotease production readily develops in media containing transferrin, whereas only pyoverdine loss emerges in medium treated with the resin. Characterization of exoprotease- and pyoverdine-less mutants revealed loss in motility, different mutations, and large genome deletions (13-33 kb) including Quorum Sensing (lasR, rsal, and lasI) and flagellar genes. Our work shows that using transferrin as an iron chelator imposes simultaneous selective pressure for the loss of pyoverdine and exoprotease production. The unintended effect of transferrin uncovered by our experiments can help to inform the design of similar studies.
Collapse
|
66
|
Camus L, Vandenesch F, Moreau K. From genotype to phenotype: adaptations of Pseudomonas aeruginosa to the cystic fibrosis environment. Microb Genom 2021; 7:mgen000513. [PMID: 33529147 PMCID: PMC8190622 DOI: 10.1099/mgen.0.000513] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 12/21/2020] [Indexed: 12/12/2022] Open
Abstract
Pseudomonas aeruginosa is one of the main microbial species colonizing the lungs of cystic fibrosis patients and is responsible for the decline in respiratory function. Despite the hostile pulmonary environment, P. aeruginosa is able to establish chronic infections thanks to its strong adaptive capacity. Various longitudinal studies have attempted to compare the strains of early infection with the adapted strains of chronic infection. Thanks to new '-omics' techniques, convergent genetic mutations, as well as transcriptomic and proteomic dysregulations have been identified. As a consequence of this evolution, the adapted strains of P. aeruginosa have particular phenotypes that promote persistent infection.
Collapse
Affiliation(s)
- Laura Camus
- CIRI – Centre International de Recherche en Infectiologie, Université de Lyon/Inserm U1111/Université Claude Bernard Lyon 1/CNRS UMR5308/ENS de Lyon, Lyon, France
| | - François Vandenesch
- CIRI – Centre International de Recherche en Infectiologie, Université de Lyon/Inserm U1111/Université Claude Bernard Lyon 1/CNRS UMR5308/ENS de Lyon, Lyon, France
- Centre National de Référence des Staphylocoques, Hospices Civils de Lyon, Lyon, France
- Institut des Agents Infectieux, Hospices Civils de Lyon, Lyon, France
| | - Karen Moreau
- CIRI – Centre International de Recherche en Infectiologie, Université de Lyon/Inserm U1111/Université Claude Bernard Lyon 1/CNRS UMR5308/ENS de Lyon, Lyon, France
| |
Collapse
|
67
|
Fritts RK, McCully AL, McKinlay JB. Extracellular Metabolism Sets the Table for Microbial Cross-Feeding. Microbiol Mol Biol Rev 2021; 85:e00135-20. [PMID: 33441489 PMCID: PMC7849352 DOI: 10.1128/mmbr.00135-20] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The transfer of nutrients between cells, or cross-feeding, is a ubiquitous feature of microbial communities with emergent properties that influence our health and orchestrate global biogeochemical cycles. Cross-feeding inevitably involves the externalization of molecules. Some of these molecules directly serve as cross-fed nutrients, while others can facilitate cross-feeding. Altogether, externalized molecules that promote cross-feeding are diverse in structure, ranging from small molecules to macromolecules. The functions of these molecules are equally diverse, encompassing waste products, enzymes, toxins, signaling molecules, biofilm components, and nutrients of high value to most microbes, including the producer cell. As diverse as the externalized and transferred molecules are the cross-feeding relationships that can be derived from them. Many cross-feeding relationships can be summarized as cooperative but are also subject to exploitation. Even those relationships that appear to be cooperative exhibit some level of competition between partners. In this review, we summarize the major types of actively secreted, passively excreted, and directly transferred molecules that either form the basis of cross-feeding relationships or facilitate them. Drawing on examples from both natural and synthetic communities, we explore how the interplay between microbial physiology, environmental parameters, and the diverse functional attributes of extracellular molecules can influence cross-feeding dynamics. Though microbial cross-feeding interactions represent a burgeoning field of interest, we may have only begun to scratch the surface.
Collapse
Affiliation(s)
- Ryan K Fritts
- Department of Biology, Indiana University, Bloomington, Indiana, USA
| | | | - James B McKinlay
- Department of Biology, Indiana University, Bloomington, Indiana, USA
| |
Collapse
|
68
|
The Rhl Quorum-Sensing System Is at the Top of the Regulatory Hierarchy under Phosphate-Limiting Conditions in Pseudomonas aeruginosa PAO1. J Bacteriol 2021; 203:JB.00475-20. [PMID: 33288622 DOI: 10.1128/jb.00475-20] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 12/02/2020] [Indexed: 12/13/2022] Open
Abstract
Pseudomonas aeruginosa is a major nosocomial pathogen that presents high-level resistance to antibiotics. Its ability to cause infections relies on the production of multiple virulence factors. Quorum sensing (QS) regulates the expression of many of these virulence factors through three QS systems: Las, Rhl, and PQS. The Las system positively regulates the other two systems, so it is at the top of a hierarchized regulation. Nevertheless, clinical and environmental strains that lack a functional Las system have been isolated, and, surprisingly, some of them still have the ability to produce virulence factors and infect animal models, so it has been suggested that the hierarchy is flexible under some conditions or with atypical strains. Here, we analyze the PAO1 type strain and its ΔlasR-derived mutant and report, for the first time, a growth condition (phosphate limitation) where LasR absence has no effect either on virulence factor production or on the gene expression profile, in contrast to a condition of phosphate repletion where the LasR hierarchy is maintained. This work provides evidence on how the QS hierarchy can change from being a strictly LasR-dependent to a LasR-independent RhlR-based hierarchy under phosphate limitation even in the PAO1 type strain.IMPORTANCE Pseudomonas aeruginosa is an important pathogen, considered a priority for the development of new therapeutic strategies. An important approach to fight its infections relies on blocking quorum sensing. The Las system is the main regulator of the quorum-sensing response, so many research efforts aim to block this system to suppress the entire response. In this work, we show that LasR is dispensable in a phosphate-limited environment in the PAO1 type strain, which has been used to define the quorum-sensing response hierarchy, and that under this condition RhlR is at the top of the regulation hierarchy. These results are highly significant, since phosphate limitation represents a similar environment to the one that P. aeruginosa faces when establishing infections.
Collapse
|
69
|
Shah M, Taylor VL, Bona D, Tsao Y, Stanley SY, Pimentel-Elardo SM, McCallum M, Bondy-Denomy J, Howell PL, Nodwell JR, Davidson AR, Moraes TF, Maxwell KL. A phage-encoded anti-activator inhibits quorum sensing in Pseudomonas aeruginosa. Mol Cell 2021; 81:571-583.e6. [PMID: 33412111 DOI: 10.1016/j.molcel.2020.12.011] [Citation(s) in RCA: 71] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 11/19/2020] [Accepted: 12/03/2020] [Indexed: 11/28/2022]
Abstract
The arms race between bacteria and phages has led to the evolution of diverse anti-phage defenses, several of which are controlled by quorum-sensing pathways. In this work, we characterize a quorum-sensing anti-activator protein, Aqs1, found in Pseudomonas phage DMS3. We show that Aqs1 inhibits LasR, the master regulator of quorum sensing, and present the crystal structure of the Aqs1-LasR complex. The 69-residue Aqs1 protein also inhibits PilB, the type IV pilus assembly ATPase protein, which blocks superinfection by phages that require the pilus for infection. This study highlights the remarkable ability of small phage proteins to bind multiple host proteins and disrupt key biological pathways. As quorum sensing influences various anti-phage defenses, Aqs1 provides a mechanism by which infecting phages might simultaneously dampen multiple defenses. Because quorum-sensing systems are broadly distributed across bacteria, this mechanism of phage counter-defense may play an important role in phage-host evolutionary dynamics.
Collapse
Affiliation(s)
- Megha Shah
- Department of Biochemistry, University of Toronto, MaRS West Tower, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Véronique L Taylor
- Department of Biochemistry, University of Toronto, MaRS West Tower, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Diane Bona
- Department of Biochemistry, University of Toronto, MaRS West Tower, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Yvonne Tsao
- Department of Biochemistry, University of Toronto, MaRS West Tower, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Sabrina Y Stanley
- Department of Molecular Genetics, University of Toronto, MaRS West Tower, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Sheila M Pimentel-Elardo
- Department of Biochemistry, University of Toronto, MaRS West Tower, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Matthew McCallum
- Department of Biochemistry, University of Toronto, MaRS West Tower, 661 University Avenue, Toronto, ON M5G 1M1, Canada; Program in Molecular Structure & Function, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Joseph Bondy-Denomy
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - P Lynne Howell
- Department of Biochemistry, University of Toronto, MaRS West Tower, 661 University Avenue, Toronto, ON M5G 1M1, Canada; Program in Molecular Structure & Function, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Justin R Nodwell
- Department of Biochemistry, University of Toronto, MaRS West Tower, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Alan R Davidson
- Department of Biochemistry, University of Toronto, MaRS West Tower, 661 University Avenue, Toronto, ON M5G 1M1, Canada; Department of Molecular Genetics, University of Toronto, MaRS West Tower, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Trevor F Moraes
- Department of Biochemistry, University of Toronto, MaRS West Tower, 661 University Avenue, Toronto, ON M5G 1M1, Canada.
| | - Karen L Maxwell
- Department of Biochemistry, University of Toronto, MaRS West Tower, 661 University Avenue, Toronto, ON M5G 1M1, Canada.
| |
Collapse
|
70
|
García-Contreras R, Loarca D. The bright side of social cheaters: potential beneficial roles of "social cheaters" in microbial communities. FEMS Microbiol Ecol 2020; 97:6006265. [PMID: 33238304 DOI: 10.1093/femsec/fiaa239] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 11/23/2020] [Indexed: 11/13/2022] Open
Abstract
Cooperation in microbial communities via production of public goods is susceptible to social cheating, since selfish individuals that do not contribute to their synthesis but benefit from their production thrive in the presence of cooperators. This behavior has been observed in the laboratory using bacterial and yeast models. Moreover, growing evidence indicates that cheating is frequent in natural microbial communities. In the laboratory, social cheating can promote population collapse or "tragedy of the commons" when excessive. Nevertheless, there are diverse mechanisms that counteract cheating in microbes, as well as theoretical and experimental evidence that suggests possible beneficial roles of social cheaters for the microbial populations. In this mini review manuscript we compile and discuss such possible roles.
Collapse
Affiliation(s)
- Rodolfo García-Contreras
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autonoma de México, Circuto Escolar 411A, Copilco Universidad, Coyoacán, 04360, Mexico City, Mexico
| | - Daniel Loarca
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autonoma de México, Circuto Escolar 411A, Copilco Universidad, Coyoacán, 04360, Mexico City, Mexico
| |
Collapse
|
71
|
Extracellular products-mediated interspecific interaction between Pseudomonas aeruginosa and Escherichia coli. J Microbiol 2020; 59:29-40. [PMID: 33355890 DOI: 10.1007/s12275-021-0478-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 10/29/2020] [Accepted: 11/11/2020] [Indexed: 10/22/2022]
Abstract
The Gram-negative pathogen Pseudomonas aeruginosa adopts several elaborate strategies to colonize a wide range of natural or clinical niches and to overcome the neighboring bacterial competitors in polymicrobial communities. However, the relationship and interaction mechanism of P. aeruginosa with other bacterial pathogens remains largely unexplored. Here we explore the interaction dynamics of P. aeruginosa and Escherichia coli, which frequently coinfect the lungs of immunocompromised hosts, by using a series of on-plate proximity assays and RNA-sequencing. We show that the extracellular products of P. aeruginosa can inhibit the growth of neighboring E. coli and induce a large-scale of transcriptional reprogramming of E. coli, especially in terms of cellular respiration-related primary metabolisms and membrane components. In contrast, the presence of E. coli has no significant effect on the growth of P. aeruginosa in short-term culture, but causes a dysregulated expression of genes positively controlled by the quorum-sensing (QS) system of P. aeruginosa during subsequent pairwise culture. We further demonstrate that the divergent QS-regulation of P. aeruginosa may be related to the function of the transcriptional regulator PqsR, which can be enhanced by E. coli culture supernatant to increase the pyocyanin production by P. aeruginosa in the absence of the central las-QS system. Moreover, the extracellular products of E. coli promote the proliferation and lethality of P. aeruginosa in infecting the Caenorhabditis elegans model. The current study provides a general characterization of the extracellular products-mediated interactions between P. aeruginosa and E. coli, and may facilitate the understanding of polymicrobial infections.
Collapse
|
72
|
Iron interferes with quorum sensing-mediated cooperation in Pseudomonas aeruginosa by affecting the expression of ppyR and mexT, in addition to rhlR. J Microbiol 2020; 58:938-944. [PMID: 32997304 DOI: 10.1007/s12275-020-0264-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 07/28/2020] [Accepted: 08/03/2020] [Indexed: 10/23/2022]
Abstract
The stabilization of quorum sensing (QS) is vital for bacterial survival in various environments. Although the mechanisms of QS stabilization in certain conditions have been well studied, the impact of environmental factors has received much less attention. In this study, we show that the supplementation of 25 µM iron in competition experiments and 50 µM in evolution experiments to casein growth cultures significantly increased the possibility of population collapse by affecting elastase production. However, the expression of lasI and lasR remained constant regardless of iron concentration and hence this effect was not through interference with the LasIR circuit, which mainly regulates the secretion of elastase in Pseudomonas aeruginosa. However, the expression of rhlR was significantly inhibited by iron treatment, which could affect the production of elastase. Further, based on both reverse transcription quantitative polymerase chain reaction and gene knock-out assays, we show that iron inhibits the transcription of ppyR and enhances the expression of mexT, both of which decrease elastase production and correspondingly interfere with QS stabilization. Our findings show that environmental factors can affect the genes of QS circuits, interfering with QS stabilization. These findings are not only beneficial in understanding the mechanistic effect of iron on QS stabilization, but also demonstrate the complexity of QS stabilization by linking non-QS-related genes with QS traits.
Collapse
|
73
|
Schilcher K, Horswill AR. Staphylococcal Biofilm Development: Structure, Regulation, and Treatment Strategies. Microbiol Mol Biol Rev 2020; 84:e00026-19. [PMID: 32792334 PMCID: PMC7430342 DOI: 10.1128/mmbr.00026-19] [Citation(s) in RCA: 307] [Impact Index Per Article: 76.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
In many natural and clinical settings, bacteria are associated with some type of biotic or abiotic surface that enables them to form biofilms, a multicellular lifestyle with bacteria embedded in an extracellular matrix. Staphylococcus aureus and Staphylococcus epidermidis, the most frequent causes of biofilm-associated infections on indwelling medical devices, can switch between an existence as single free-floating cells and multicellular biofilms. During biofilm formation, cells first attach to a surface and then multiply to form microcolonies. They subsequently produce the extracellular matrix, a hallmark of biofilm formation, which consists of polysaccharides, proteins, and extracellular DNA. After biofilm maturation into three-dimensional structures, the biofilm community undergoes a disassembly process that leads to the dissemination of staphylococcal cells. As biofilms are dynamic and complex biological systems, staphylococci have evolved a vast network of regulatory mechanisms to modify and fine-tune biofilm development upon changes in environmental conditions. Thus, biofilm formation is used as a strategy for survival and persistence in the human host and can serve as a reservoir for spreading to new infection sites. Moreover, staphylococcal biofilms provide enhanced resilience toward antibiotics and the immune response and impose remarkable therapeutic challenges in clinics worldwide. This review provides an overview and an updated perspective on staphylococcal biofilms, describing the characteristic features of biofilm formation, the structural and functional properties of the biofilm matrix, and the most important mechanisms involved in the regulation of staphylococcal biofilm formation. Finally, we highlight promising strategies and technologies, including multitargeted or combinational therapies, to eradicate staphylococcal biofilms.
Collapse
Affiliation(s)
- Katrin Schilcher
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Alexander R Horswill
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA
- Department of Veterans Affairs Eastern Colorado Health Care System, Denver, Colorado, USA
| |
Collapse
|
74
|
Schilcher K, Horswill AR. Staphylococcal Biofilm Development: Structure, Regulation, and Treatment Strategies. Microbiol Mol Biol Rev 2020. [PMID: 32792334 DOI: 10.1128/mmbr.00026-19/asset/e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2023] Open
Abstract
In many natural and clinical settings, bacteria are associated with some type of biotic or abiotic surface that enables them to form biofilms, a multicellular lifestyle with bacteria embedded in an extracellular matrix. Staphylococcus aureus and Staphylococcus epidermidis, the most frequent causes of biofilm-associated infections on indwelling medical devices, can switch between an existence as single free-floating cells and multicellular biofilms. During biofilm formation, cells first attach to a surface and then multiply to form microcolonies. They subsequently produce the extracellular matrix, a hallmark of biofilm formation, which consists of polysaccharides, proteins, and extracellular DNA. After biofilm maturation into three-dimensional structures, the biofilm community undergoes a disassembly process that leads to the dissemination of staphylococcal cells. As biofilms are dynamic and complex biological systems, staphylococci have evolved a vast network of regulatory mechanisms to modify and fine-tune biofilm development upon changes in environmental conditions. Thus, biofilm formation is used as a strategy for survival and persistence in the human host and can serve as a reservoir for spreading to new infection sites. Moreover, staphylococcal biofilms provide enhanced resilience toward antibiotics and the immune response and impose remarkable therapeutic challenges in clinics worldwide. This review provides an overview and an updated perspective on staphylococcal biofilms, describing the characteristic features of biofilm formation, the structural and functional properties of the biofilm matrix, and the most important mechanisms involved in the regulation of staphylococcal biofilm formation. Finally, we highlight promising strategies and technologies, including multitargeted or combinational therapies, to eradicate staphylococcal biofilms.
Collapse
Affiliation(s)
- Katrin Schilcher
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Alexander R Horswill
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA
- Department of Veterans Affairs Eastern Colorado Health Care System, Denver, Colorado, USA
| |
Collapse
|
75
|
Aframian N, Eldar A. A Bacterial Tower of Babel: Quorum-Sensing Signaling Diversity and Its Evolution. Annu Rev Microbiol 2020; 74:587-606. [PMID: 32680450 DOI: 10.1146/annurev-micro-012220-063740] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Quorum sensing is a process in which bacteria secrete and sense a diffusible molecule, thereby enabling bacterial groups to coordinate their behavior in a density-dependent manner. Quorum sensing has evolved multiple times independently, utilizing different molecular pathways and signaling molecules. A common theme among many quorum-sensing families is their wide range of signaling diversity-different variants within a family code for different signal molecules with a cognate receptor specific to each variant. This pattern of vast allelic polymorphism raises several questions-How do different signaling variants interact with one another? How is this diversity maintained? And how did it come to exist in the first place? Here we argue that social interactions between signaling variants can explain the emergence and persistence of signaling diversity throughout evolution. Finally, we extend the discussion to include cases where multiple diverse systems work in concert in a single bacterium.
Collapse
Affiliation(s)
- Nitzan Aframian
- Faculty of Life Sciences, School of Molecular Cell Biology and Biotechnology, Tel-Aviv University, 6997801 Tel-Aviv, Israel; ,
| | - Avigdor Eldar
- Faculty of Life Sciences, School of Molecular Cell Biology and Biotechnology, Tel-Aviv University, 6997801 Tel-Aviv, Israel; ,
| |
Collapse
|
76
|
Banzhaf M, Resendis-Antonio O, Zepeda-Mendoza ML. Uncovering the Dynamic Mechanisms of the Pseudomonas Aeruginosa Quorum Sensing and Virulence Networks Using Boolean Modelling. IEEE Trans Nanobioscience 2020; 19:394-402. [DOI: 10.1109/tnb.2020.2977820] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
77
|
For the Greater (Bacterial) Good: Heterogeneous Expression of Energetically Costly Virulence Factors. Infect Immun 2020; 88:IAI.00911-19. [PMID: 32041785 DOI: 10.1128/iai.00911-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Bacterial populations are phenotypically heterogeneous, which allows subsets of cells to survive and thrive following changes in environmental conditions. For bacterial pathogens, changes within the host environment occur over the course of the immune response to infection and can result in exposure to host-derived, secreted antimicrobials or force direct interactions with immune cells. Many recent studies have shown host cell interactions promote virulence factor expression, forcing subsets of bacterial cells to battle the host response, while other bacteria reap the benefits of this pacification. It still remains unclear whether virulence factor expression is truly energetically costly within host tissues and whether expression is sufficient to impact the growth kinetics of virulence factor-expressing cells. However, it is clear that slow-growing subsets of bacteria emerge during infection and that these subsets are particularly difficult to eliminate with antibiotics. This minireview will focus on our current understanding of heterogenous virulence factor expression and discuss the evidence that supports or refutes the hypothesis that virulence factor expression is linked to slowed growth and antibiotic tolerance.
Collapse
|
78
|
Robitaille S, Groleau M, Déziel E. Swarming motility growth favours the emergence of a subpopulation ofPseudomonas aeruginosaquorum‐sensing mutants. Environ Microbiol 2020; 22:2892-2906. [DOI: 10.1111/1462-2920.15042] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 04/22/2020] [Indexed: 01/16/2023]
Affiliation(s)
- Sophie Robitaille
- Centre Armand‐Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique (INRS) 531 Boulevard des Prairies, Laval QC H7V 1B7 Canada
| | - Marie‐Christine Groleau
- Centre Armand‐Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique (INRS) 531 Boulevard des Prairies, Laval QC H7V 1B7 Canada
| | - Eric Déziel
- Centre Armand‐Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique (INRS) 531 Boulevard des Prairies, Laval QC H7V 1B7 Canada
| |
Collapse
|
79
|
Zhao K, Li J, Yuan Y, Lin J, Wang X, Guo Y, Chu Y. Nutrient factor-dependent performance of bacterial quorum sensing system during population evolution. Arch Microbiol 2020; 202:2181-2188. [PMID: 32519021 DOI: 10.1007/s00203-020-01937-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 02/26/2020] [Accepted: 06/04/2020] [Indexed: 11/26/2022]
Abstract
Bacterial quorum sensing (QS) system regulates the production of most costly but sharable extracellular products (public goods) in a growth-phase-dependent manner, and the development of this energy-intensive process is susceptible to environmental changes. However, the role of nutrient factors in dominating the QS-mediated cooperative interaction and intracellular metabolism still remains less understood. Here we studied the performance of QS system by growing Pseudomonas aeruginosa under different nutrient and culture conditions. The results of comparative-transcriptomic analyses revealed that carbon source-limitation was the main factor suppressing the activation of QS system, and a substantial number of public-good-encoding genes were induced when phosphorus is limiting in short-term culture. By contrast, although the QS regulation of P. aeruginosa in all the cultures was generally decreased along with the enrichment of QS-deficient individuals during evolution, limitation of different nutrient factors had discrepant effects in directing the formation of population structure by coordinating the production of public goods and primary metabolism, especially the starch and sucrose metabolism. These findings demonstrate the pleiotropy of QS regulation in balancing the development of cooperative behavior and metabolism, and provide a reference for further understanding the role of QS system in causing persistent infections.
Collapse
Affiliation(s)
- Kelei Zhao
- Antibiotics Research and Re-Evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, Chengdu University, No. 168, Huaguan Road, Chengdu, 610052, Sichuan, China.
| | - Jing Li
- Antibiotics Research and Re-Evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, Chengdu University, No. 168, Huaguan Road, Chengdu, 610052, Sichuan, China
| | - Yang Yuan
- Antibiotics Research and Re-Evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, Chengdu University, No. 168, Huaguan Road, Chengdu, 610052, Sichuan, China
| | - Jiafu Lin
- Antibiotics Research and Re-Evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, Chengdu University, No. 168, Huaguan Road, Chengdu, 610052, Sichuan, China
| | - Xinrong Wang
- Antibiotics Research and Re-Evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, Chengdu University, No. 168, Huaguan Road, Chengdu, 610052, Sichuan, China
| | - Yidong Guo
- Antibiotics Research and Re-Evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, Chengdu University, No. 168, Huaguan Road, Chengdu, 610052, Sichuan, China
| | - Yiwen Chu
- Antibiotics Research and Re-Evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, Chengdu University, No. 168, Huaguan Road, Chengdu, 610052, Sichuan, China.
| |
Collapse
|
80
|
Gurney J, Azimi S, Brown SP, Diggle SP. Combinatorial quorum sensing in Pseudomonas aeruginosa allows for novel cheating strategies. MICROBIOLOGY-SGM 2020; 166:777-784. [PMID: 32511085 DOI: 10.1099/mic.0.000941] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In the opportunistic pathogen Pseudomonas aeruginosa, quorum sensing (QS) is a social trait that is exploitable by non-cooperating cheats. Previously it has been shown that by linking QS to the production of both public and private goods, cheats can be prevented from invading populations of cooperators and this was described by Dandekar et al. (Science 2012;338:264-266) as 'a metabolic incentive to cooperate'. We hypothesized that P. aeruginosa could evolve novel cheating strategies to circumvent private goods metabolism by rewiring its combinatorial response to two QS signals (3O-C12-HSL and C4-HSL). We performed a selection experiment that cycled P. aeruginosa between public and private goods growth media and evolved an isolate that rewired its control of cooperative protease expression from a synergistic (AND-gate) response to dual-signal input to a 3O-C12-HSL-only response. We show that this isolate circumvents metabolic incentives to cooperate and acts as a combinatorial signalling cheat, with higher fitness in competition with its ancestor. Our results show three important principles: first, combinatorial QS allows for diverse social strategies to emerge; second, restrictions levied by private goods are not sufficient to explain the maintenance of cooperation in natural populations; and third, modifying combinatorial QS responses could result in important physiological outcomes in bacterial populations.
Collapse
Affiliation(s)
- James Gurney
- School of Biological Sciences, Georgia Institute of Technology, Atlanta,, USA.,Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, USA
| | - Sheyda Azimi
- School of Biological Sciences, Georgia Institute of Technology, Atlanta,, USA.,Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, USA
| | - Sam P Brown
- School of Biological Sciences, Georgia Institute of Technology, Atlanta,, USA.,Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, USA
| | - Stephen P Diggle
- School of Biological Sciences, Georgia Institute of Technology, Atlanta,, USA.,Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, USA
| |
Collapse
|
81
|
Wang S, Payne GF, Bentley WE. Quorum Sensing Communication: Molecularly Connecting Cells, Their Neighbors, and Even Devices. Annu Rev Chem Biomol Eng 2020; 11:447-468. [DOI: 10.1146/annurev-chembioeng-101519-124728] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Quorum sensing (QS) is a molecular signaling modality that mediates molecular-based cell–cell communication. Prevalent in nature, QS networks provide bacteria with a method to gather information from the environment and make decisions based on the intel. With its ability to autonomously facilitate both inter- and intraspecies gene regulation, this process can be rewired to enable autonomously actuated, but molecularly programmed, genetic control. On the one hand, novel QS-based genetic circuits endow cells with smart functions that can be used in many fields of engineering, and on the other, repurposed QS circuitry promotes communication and aids in the development of synthetic microbial consortia. Furthermore, engineered QS systems can probe and intervene in interkingdom signaling between bacteria and their hosts. Lastly, QS is demonstrated to establish conversation with abiotic materials, especially by taking advantage of biological and even electronically induced assembly processes; such QS-incorporated biohybrid devices offer innovative ways to program cell behavior and biological function.
Collapse
Affiliation(s)
- Sally Wang
- Fischell Department of Bioengineering, University of Maryland, College Park, Maryland 20742, USA
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, Maryland 20850, USA
- Robert E. Fischell Institute for Biomedical Devices, University of Maryland, College Park, Maryland 20742, USA
| | - Gregory F. Payne
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, Maryland 20850, USA
- Robert E. Fischell Institute for Biomedical Devices, University of Maryland, College Park, Maryland 20742, USA
| | - William E. Bentley
- Fischell Department of Bioengineering, University of Maryland, College Park, Maryland 20742, USA
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, Maryland 20850, USA
- Robert E. Fischell Institute for Biomedical Devices, University of Maryland, College Park, Maryland 20742, USA
| |
Collapse
|
82
|
Optimal Response to Quorum-Sensing Signals Varies in Different Host Environments with Different Pathogen Group Size. mBio 2020; 11:mBio.00535-20. [PMID: 32487754 PMCID: PMC7267880 DOI: 10.1128/mbio.00535-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Quorum sensing describes the ability of microbes to alter gene regulation according to their local population size. Some successful theory suggests that this is a form of cooperation, namely, investment in shared products is only worthwhile if there are sufficient bacteria making the same product. This theory can explain the genetic diversity in these signaling systems in Gram-positive bacteria, such as Bacillus and Staphylococcus sp. The possible advantages gained by rare genotypes (which can exploit the products of their more common neighbors) could explain why different genotypes can coexist. We show that while these social interactions can occur in simple laboratory experiments, they do not occur in naturalistic infections using an invertebrate pathogen, Bacillus thuringiensis. Instead, our results suggest that different genotypes are adapted to differently sized hosts. Overall, social models are not easily applied to this system, implying that a different explanation for this form of quorum sensing is required. The persistence of genetic variation in master regulators of gene expression, such as quorum-sensing systems, is hard to explain. Here, we investigated two alternative hypotheses for the prevalence of polymorphic quorum sensing in Gram-positive bacteria, i.e., the use of different signal/receptor pairs (‘pherotypes’) to regulate the same functions. First, social interactions between pherotypes or ‘facultative cheating’ may favor rare variants that exploit the signals of others. Second, different pherotypes may increase fitness in different environments. We evaluated these hypotheses in the invertebrate pathogen Bacillus thuringiensis, using three pherotypes expressed in a common genetic background. Facultative cheating could occur in well-mixed host homogenates provided there was minimal cross talk between competing pherotypes. However, facultative cheating did not occur when spatial structure was increased in static cultures or in naturalistic oral infections, where common pherotypes had higher fitness. There was clear support for environment-dependent fitness; pherotypes varied in responsiveness to signals and in mean competitive fitness. Notably, competitive fitness varied with group size. In contrast to typical social evolution models of quorum sensing which predict higher response to signal at larger group size, the pherotype with highest responsiveness to signals performed best in smaller hosts where infections have a lower pathogen group size. In this system, low signal abundance appears to limit fitness in hosts, while the optimal level of response to signals varies in different host environments.
Collapse
|
83
|
Wang Y, Rattray JB, Thomas SA, Gurney J, Brown SP. In silico bacteria evolve robust cooperaion via complex quorum-sensing strategies. Sci Rep 2020; 10:8628. [PMID: 32451396 PMCID: PMC7248119 DOI: 10.1038/s41598-020-65076-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Accepted: 04/28/2020] [Indexed: 12/22/2022] Open
Abstract
Many species of bacteria collectively sense and respond to their social and physical environment via 'quorum sensing' (QS), a communication system controlling extracellular cooperative traits. Despite detailed understanding of the mechanisms of signal production and response, there remains considerable debate over the functional role(s) of QS: in short, what is it for? Experimental studies have found support for diverse functional roles: density sensing, mass-transfer sensing, genotype sensing, etc. While consistent with theory, these results cannot separate whether these functions were drivers of QS adaption, or simply artifacts or 'spandrels' of systems shaped by distinct ecological pressures. The challenge of separating spandrels from drivers of adaptation is particularly hard to address using extant bacterial species with poorly understood current ecologies (let alone their ecological histories). To understand the relationship between defined ecological challenges and trajectories of QS evolution, we used an agent-based simulation modeling approach. Given genetic mixing, our simulations produce behaviors that recapitulate features of diverse microbial QS systems, including coercive (high signal/low response) and generalized reciprocity (signal auto-regulation) strategists - that separately and in combination contribute to QS-dependent resilience of QS-controlled cooperation in the face of diverse cheats. We contrast our in silico results given defined ecological challenges with bacterial QS architectures that have evolved under largely unknown ecological contexts, highlighting the critical role of genetic constraints in shaping the shorter term (experimental evolution) dynamics of QS. More broadly, we see experimental evolution of digital organisms as a complementary tool in the search to understand the emergence of complex QS architectures and functions.
Collapse
Affiliation(s)
- Yifei Wang
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, 30332 GA, USA.
- The Institute for Data Engineering and Science (IDEaS), Georgia Institute of Technology, Atlanta, 30332 GA, USA.
- Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, 30332 GA, USA.
| | - Jennifer B Rattray
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, 30332 GA, USA
- Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, 30332 GA, USA
| | - Stephen A Thomas
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, 30332 GA, USA
- Graduate Program in Quantitative Biosciences (QBioS), Georgia Institute of Technology, Atlanta, 30332 GA, USA
- Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, 30332 GA, USA
| | - James Gurney
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, 30332 GA, USA
- Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, 30332 GA, USA
| | - Sam P Brown
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, 30332 GA, USA.
- Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, 30332 GA, USA.
| |
Collapse
|
84
|
García-Contreras R, Loarca D, Pérez-González C, Jiménez-Cortés JG, Gonzalez-Valdez A, Soberón-Chávez G. Rhamnolipids stabilize quorum sensing mediated cooperation in Pseudomonas aeruginosa. FEMS Microbiol Lett 2020; 367:5837079. [PMID: 32407463 DOI: 10.1093/femsle/fnaa080] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Accepted: 05/12/2020] [Indexed: 12/24/2022] Open
Abstract
Pseudomonas aeruginosa is one of the main models to study social behaviors in bacteria since it synthesizes several exoproducts, including exoproteases and siderophores and release them to the environment. Exoproteases and siderophores are public goods that can be utilized by the individuals that produce them but also by non-producers, that are considered social cheaters. Molecularly exoprotease cheaters are mutants in regulatory genes such as lasR, and are commonly isolated from chronic infections and selected in the laboratory upon serial cultivation in media with protein as a sole carbon source. Despite that the production of exoproteases is exploitable, cooperators have also ways to restrict the growth and selection of social cheaters, for instance by producing toxic metabolites like pyocyanin. In this work, using bacterial competitions, serial cultivation and growth assays, we demonstrated that rhamnolipids which production is regulated by quorum sensing, selectively affect the growth of lasR mutants and are able to restrict social cheating, hence contributing to the maintenance of cooperation in Pseudomonas aeruginosa populations.
Collapse
Affiliation(s)
- Rodolfo García-Contreras
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Circuto Escolar 411A, Copilco Universidad, Coyoacán, 04360, Mexico City, Mexico
| | - Daniel Loarca
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Circuto Escolar 411A, Copilco Universidad, Coyoacán, 04360, Mexico City, Mexico
| | - Caleb Pérez-González
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Circuto Escolar 411A, Copilco Universidad, Coyoacán, 04360, Mexico City, Mexico
| | - J Guillermo Jiménez-Cortés
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Circuto Escolar 411A, Copilco Universidad, Coyoacán, 04360, Mexico City, Mexico
| | - Abigail Gonzalez-Valdez
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Tercer Circuito Exterior, Ciudad Universitaria, Apdo. Postal 70228, C. P. 04510, CDMX, México
| | - Gloria Soberón-Chávez
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Tercer Circuito Exterior, Ciudad Universitaria, Apdo. Postal 70228, C. P. 04510, CDMX, México
| |
Collapse
|
85
|
Bateman A. Division of labour in a matrix, rather than phagocytosis or endosymbiosis, as a route for the origin of eukaryotic cells. Biol Direct 2020; 15:8. [PMID: 32345370 PMCID: PMC7187495 DOI: 10.1186/s13062-020-00260-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 02/25/2020] [Indexed: 12/13/2022] Open
Abstract
Abstract Two apparently irreconcilable models dominate research into the origin of eukaryotes. In one model, amitochondrial proto-eukaryotes emerged autogenously from the last universal common ancestor of all cells. Proto-eukaryotes subsequently acquired mitochondrial progenitors by the phagocytic capture of bacteria. In the second model, two prokaryotes, probably an archaeon and a bacterial cell, engaged in prokaryotic endosymbiosis, with the species resident within the host becoming the mitochondrial progenitor. Both models have limitations. A search was therefore undertaken for alternative routes towards the origin of eukaryotic cells. The question was addressed by considering classes of potential pathways from prokaryotic to eukaryotic cells based on considerations of cellular topology. Among the solutions identified, one, called here the “third-space model”, has not been widely explored. A version is presented in which an extracellular space (the third-space), serves as a proxy cytoplasm for mixed populations of archaea and bacteria to “merge” as a transitionary complex without obligatory endosymbiosis or phagocytosis and to form a precursor cell. Incipient nuclei and mitochondria diverge by division of labour. The third-space model can accommodate the reorganization of prokaryote-like genomes to a more eukaryote-like genome structure. Nuclei with multiple chromosomes and mitosis emerge as a natural feature of the model. The model is compatible with the loss of archaeal lipid biochemistry while retaining archaeal genes and provides a route for the development of membranous organelles such as the Golgi apparatus and endoplasmic reticulum. Advantages, limitations and variations of the “third-space” models are discussed. Reviewers This article was reviewed by Damien Devos, Buzz Baum and Michael Gray.
Collapse
Affiliation(s)
- Andrew Bateman
- Division of Experimental Medicine, Department of Medicine, McGill University, Glen Site Pavilion E, 1001 Boulevard Decarie, Montreal, Quebec, H4A 3J1, Canada. .,Centre for Translational Biology, Research Institute of McGill University Health Centre, Glen Site Pavilion E, 1001 Boulevard Decarie, Montreal, Quebec, H4A 3J1, Canada.
| |
Collapse
|
86
|
Gerner E, Almqvist S, Werthén M, Trobos M. Sodium salicylate interferes with quorum-sensing-regulated virulence in chronic wound isolates of Pseudomonas aeruginosa in simulated wound fluid. J Med Microbiol 2020; 69:767-780. [PMID: 32320374 PMCID: PMC7451038 DOI: 10.1099/jmm.0.001188] [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] [Indexed: 01/21/2023] Open
Abstract
Introduction. An important factor for delayed healing of chronic wounds is the presence of bacteria. Quorum sensing (QS), a cell density-dependent signalling system, controls the production of many virulence factors and biofilm formation in Pseudomonas aeruginosa.Aim. Inhibition by sodium salicylate (NaSa) of QS-regulated virulence expression was evaluated in QS-characterized clinical wound isolates of P. aeruginosa, cultured in serum-containing medium.Methodology. Fourteen clinical P. aeruginosa strains from chronic wounds were evaluated for the production of QS signals and virulence factors. Inhibition of QS by NaSa in P. aeruginosa clinical strains, wild-type PAO1 and QS reporter strains was evaluated using in vitro assays for the production of biofilm, pyocyanin, siderophores, alkaline protease, elastase and stapholytic protease.Results. Six clinical strains secreted several QS-associated virulence factors and signal molecules and two were negative for all factors. Sub-inhibitory concentrations of NaSa downregulated the expression of the QS-related genes lasB, rhlA and pqsA and reduced the secretion of several virulence factors in PAO1 and clinical strains cultured in serum. Compared to serum-free media, the presence of serum increased the expression of QS genes and production of siderophores and pyocyanin but decreased biofilm formation.Conclusions. Pseudomonas aeruginosa from chronic wound infections showed different virulence properties. While very few strains showed no QS activity, approximately half were highly virulent and produced QS signals, suggesting that the targeting of QS is a viable and relevant strategy for infection control. NaSa showed activity as a QS-inhibitor by lowering the virulence phenotypes and QS signals at both transcriptional and extracellular levels.
Collapse
Affiliation(s)
- Erik Gerner
- Department of Biomaterials, The Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden.,Mölnlycke Health Care AB, Gothenburg, Sweden.,Center for Antibiotic Resistance Research (CARe) at University of Gothenburg, Gothenburg, Sweden
| | | | - Maria Werthén
- Department of Biomaterials, The Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden.,Center for Antibiotic Resistance Research (CARe) at University of Gothenburg, Gothenburg, Sweden.,Department of Health Sciences, University West, Trollhättan, Sweden
| | - Margarita Trobos
- Department of Biomaterials, The Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden.,Center for Antibiotic Resistance Research (CARe) at University of Gothenburg, Gothenburg, Sweden
| |
Collapse
|
87
|
Cooperation and Cheating through a Secreted Aminopeptidase in the Pseudomonas aeruginosa RpoS Response. mBio 2020; 11:mBio.03090-19. [PMID: 32184248 PMCID: PMC7078477 DOI: 10.1128/mbio.03090-19] [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] [Indexed: 01/13/2023] Open
Abstract
Bacterial stress responses are generally considered protective measures taken by individual cells. Enabled by an experimental evolution approach, we describe a contrasting property, collective nutrient acquisition, in the RpoS-dependent stress response of the opportunistic human pathogen P. aeruginosa. Specifically, we identify the secreted P. aeruginosa aminopeptidase (PaAP) as an essential RpoS-controlled function in extracellular proteolysis. As a secreted “public good,” PaAP permits cheating by rpoS mutants that save the metabolic costs of expressing RpoS-controlled genes dispensable under the given growth conditions. Proteolytic enzymes are important virulence factors in P. aeruginosa pathogenesis and constitute a potential target for antimicrobial therapy. More broadly, our work contributes to recent findings in higher organisms that stress affects not only individual fitness and competitiveness but also cooperative behavior. The global stress response controlled by the alternative sigma factor RpoS protects enteric bacteria from a variety of environmental stressors. The role of RpoS in other, nonenteric bacteria, such as the opportunistic pathogen Pseudomonas aeruginosa, is less well understood. Here, we employed experimental social evolution to reveal that cooperative behavior via secreted public goods is an important function in the RpoS response of P. aeruginosa. Using whole-genome sequencing, we identified rpoS loss-of-function mutants among isolates evolved in a protein growth medium that requires extracellular proteolysis. We found that rpoS mutants comprise up to 25% of the evolved population and that they behave as social cheaters, with low fitness in isolation but high fitness in mixed culture with the cooperating wild type. We conclude that rpoS mutants cheat because they exploit an RpoS-controlled public good produced by the wild type, the secreted aminopeptidase PaAP, and because they do not carry the metabolic costs of expressing PaAP and many other gene products in the large RpoS regulon. Our results suggest that PaAP is an integral part of a proteolytic sequence in P. aeruginosa that permits the utilization of protein as a nutrient source. Our work broadens the scope of stress response functions in bacteria.
Collapse
|
88
|
Abstract
Bacteria harbor viruses called bacteriophages that, like all viruses, co-opt the host cellular machinery to replicate. Although this relationship is at first glance parasitic, there are social interactions among and between bacteriophages and their bacterial hosts. These social interactions can take on many forms, including cooperation, altruism, and cheating. Such behaviors among individuals in groups of bacteria have been well described. However, the social nature of some interactions between phages or phages and bacteria is only now becoming clear. Bacteria harbor viruses called bacteriophages that, like all viruses, co-opt the host cellular machinery to replicate. Although this relationship is at first glance parasitic, there are social interactions among and between bacteriophages and their bacterial hosts. These social interactions can take on many forms, including cooperation, altruism, and cheating. Such behaviors among individuals in groups of bacteria have been well described. However, the social nature of some interactions between phages or phages and bacteria is only now becoming clear. We are just beginning to understand how bacteriophages affect the sociobiology of bacteria, and we know even less about social interactions within bacteriophage populations. In this review, we discuss recent developments in our understanding of bacteriophage sociobiology, including how selective pressures influence the outcomes of social interactions between populations of bacteria and bacteriophages. We also explore how tripartite social interactions between bacteria, bacteriophages, and an animal host affect host-microbe interactions. Finally, we argue that understanding the sociobiology of bacteriophages will have implications for the therapeutic use of bacteriophages to treat bacterial infections.
Collapse
|
89
|
Mukherjee S, Bassler BL. Bacterial quorum sensing in complex and dynamically changing environments. Nat Rev Microbiol 2020; 17:371-382. [PMID: 30944413 DOI: 10.1038/s41579-019-0186-5] [Citation(s) in RCA: 570] [Impact Index Per Article: 142.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Quorum sensing is a process of bacterial cell-to-cell chemical communication that relies on the production, detection and response to extracellular signalling molecules called autoinducers. Quorum sensing allows groups of bacteria to synchronously alter behaviour in response to changes in the population density and species composition of the vicinal community. Quorum-sensing-mediated communication is now understood to be the norm in the bacterial world. Elegant research has defined quorum-sensing components and their interactions, for the most part, under ideal and highly controlled conditions. Indeed, these seminal studies laid the foundations for the field. In this Review, we highlight new findings concerning how bacteria deploy quorum sensing in realistic scenarios that mimic nature. We focus on how quorums are detected and how quorum sensing controls group behaviours in complex and dynamically changing environments such as multi-species bacterial communities, in the presence of flow, in 3D non-uniform biofilms and in hosts during infection.
Collapse
Affiliation(s)
- Sampriti Mukherjee
- Princeton University, Department of Molecular Biology, Princeton, NJ, USA
| | - Bonnie L Bassler
- Princeton University, Department of Molecular Biology, Princeton, NJ, USA. .,Howard Hughes Medical Institute, Chevy Chase, MD, USA.
| |
Collapse
|
90
|
Uppal G, Vural DC. Evolution of specialized microbial cooperation in dynamic fluids. J Evol Biol 2020; 33:256-269. [DOI: 10.1111/jeb.13593] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 01/16/2020] [Accepted: 01/20/2020] [Indexed: 12/28/2022]
|
91
|
Pseudomonas aeruginosa lasR mutant fitness in microoxia is supported by an Anr-regulated oxygen-binding hemerythrin. Proc Natl Acad Sci U S A 2020; 117:3167-3173. [PMID: 31980538 DOI: 10.1073/pnas.1917576117] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Pseudomonas aeruginosa strains with loss-of-function mutations in the transcription factor LasR are frequently encountered in the clinic and the environment. Among the characteristics common to LasR-defective (LasR-) strains is increased activity of the transcription factor Anr, relative to their LasR+ counterparts, in low-oxygen conditions. One of the Anr-regulated genes found to be highly induced in LasR- strains was PA14_42860 (PA1673), which we named mhr for microoxic hemerythrin. Purified P. aeruginosa Mhr protein contained the predicted di-iron center and bound molecular oxygen with an apparent K d of ∼1 µM. Both Anr and Mhr were necessary for fitness in lasR+ and lasR mutant strains in colony biofilms grown in microoxic conditions, and the effects were more striking in the lasR mutant. Among genes in the Anr regulon, mhr was most closely coregulated with the Anr-controlled high-affinity cytochrome c oxidase genes. In the absence of high-affinity cytochrome c oxidases, deletion of mhr no longer caused a fitness disadvantage, suggesting that Mhr works in concert with microoxic respiration. We demonstrate that Anr and Mhr contribute to LasR- strain fitness even in biofilms grown in normoxic conditions. Furthermore, metabolomics data indicate that, in a lasR mutant, expression of Anr-regulated mhr leads to differences in metabolism in cells grown on lysogeny broth or artificial sputum medium. We propose that increased Anr activity leads to higher levels of the oxygen-binding protein Mhr, which confers an advantage to lasR mutants in microoxic conditions.
Collapse
|
92
|
Mahan K, Martinmaki R, Larus I, Sikdar R, Dunitz J, Elias M. Effects of Signal Disruption Depends on the Substrate Preference of the Lactonase. Front Microbiol 2020; 10:3003. [PMID: 31993034 PMCID: PMC6971184 DOI: 10.3389/fmicb.2019.03003] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 12/12/2019] [Indexed: 12/19/2022] Open
Abstract
Many bacteria produce and use extracellular signaling molecules such as acyl homoserine lactones (AHLs) to communicate and coordinate behavior in a cell-density dependent manner, via a communication system called quorum sensing (QS). This system regulates behaviors including but not limited to virulence and biofilm formation. We focused on Pseudomonas aeruginosa, a human opportunistic pathogen that is involved in acute and chronic lung infections and which disproportionately affects people with cystic fibrosis. P. aeruginosa infections are becoming increasingly challenging to treat with the spread of antibiotic resistance. Therefore, QS disruption approaches, known as quorum quenching, are appealing due to their potential to control the virulence of resistant strains. Interestingly, P. aeruginosa is known to simultaneously utilize two main QS circuits, one based on C4-AHL, the other with 3-oxo-C12-AHL. Here, we evaluated the effects of signal disruption on 39 cystic fibrosis clinical isolates of P. aeruginosa, including drug resistant strains. We used two enzymes capable of degrading AHLs, known as lactonases, with distinct substrate preference: one degrading 3-oxo-C12-AHL, the other degrading both C4-AHL and 3-oxo-C12-AHL. Two lactonases were used to determine the effects of signal disruption on the clinical isolates, and to evaluate the importance of the QS circuits by measuring effects on virulence factors (elastase, protease, and pyocyanin) and biofilm formation. Signal disruption results in at least one of these factors being inhibited for most isolates (92%). Virulence factor activity or production were inhibited by up to 100% and biofilm was inhibited by an average of 2.3 fold. Remarkably, the treatments led to distinct inhibition profiles of the isolates; the treatment with the lactonase degrading both signaling molecules resulted in a higher fraction of inhibited isolates (77% vs. 67%), and the simultaneous inhibition of more virulence factors per strain (2 vs. 1.5). This finding suggests that the lactonase AHL preference is key to its inhibitory spectrum and is an essential parameter to improve quorum quenching strategies.
Collapse
Affiliation(s)
- Kathleen Mahan
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN, United States
| | - Ryan Martinmaki
- Department of Biochemistry, Molecular Biology and Biophysics, Biotechnology Institute, University of Minnesota, Saint Paul, MN, United States
| | - Isabel Larus
- Department of Biochemistry, Molecular Biology and Biophysics, Biotechnology Institute, University of Minnesota, Saint Paul, MN, United States
| | - Rakesh Sikdar
- Department of Biochemistry, Molecular Biology and Biophysics, Biotechnology Institute, University of Minnesota, Saint Paul, MN, United States
| | - Jordan Dunitz
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN, United States
- Department of Medicine, Minnesota Cystic Fibrosis Center and Adult CF Program, University of Minnesota, Minneapolis, MN, United States
| | - Mikael Elias
- Department of Biochemistry, Molecular Biology and Biophysics, Biotechnology Institute, University of Minnesota, Saint Paul, MN, United States
| |
Collapse
|
93
|
Hernando-Amado S, Sanz-García F, Martínez JL. Antibiotic Resistance Evolution Is Contingent on the Quorum-Sensing Response in Pseudomonas aeruginosa. Mol Biol Evol 2020; 36:2238-2251. [PMID: 31228244 DOI: 10.1093/molbev/msz144] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Different works have explored independently the evolution toward antibiotic resistance and the role of eco-adaptive mutations in the adaptation to a new habitat (as the infected host) of bacterial pathogens. However, knowledge about the connection between both processes is still limited. We address this issue by comparing the evolutionary trajectories toward antibiotic resistance of a Pseudomonas aeruginosa lasR defective mutant and its parental wild-type strain, when growing in presence of two ribosome-targeting antibiotics. Quorum-sensing lasR defective mutants are selected in P. aeruginosa populations causing chronic infections. Further, we observed they are also selected in vitro as a first adaptation for growing in culture medium. By using experimental evolution and whole-genome sequencing, we found that the evolutionary trajectories of P. aeruginosa in presence of these antibiotics are different in lasR defective and in wild-type backgrounds, both at the phenotypic and the genotypic levels. Recreation of a set of mutants in both genomic backgrounds (either wild type or lasR defective) allowed us to determine the existence of negative epistatic interactions between lasR and antibiotic resistance determinants. These epistatic interactions could lead to mutual contingency in the evolution of antibiotic resistance when P. aeruginosa colonizes a new habitat in presence of antibiotics. If lasR mutants are selected first, this would constraint antibiotic resistance evolution. Conversely, when resistance mutations (at least those studied in the present work) are selected, lasR mutants may not be selected in presence of antibiotics. These results underlie the importance of contingency and epistatic interactions in modulating antibiotic resistance evolution.
Collapse
|
94
|
Li T, Wang D, Ren L, Mei Y, Ding T, Li Q, Chen H, Li J. Involvement of Exogenous N-Acyl-Homoserine Lactones in Spoilage Potential of Pseudomonas fluorescens Isolated From Refrigerated Turbot. Front Microbiol 2019; 10:2716. [PMID: 31849873 PMCID: PMC6895499 DOI: 10.3389/fmicb.2019.02716] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 11/08/2019] [Indexed: 01/18/2023] Open
Abstract
Some bacteria can modulate their spoilage potential by responding to environmental signaling molecules via the quorum sensing (QS) system. However, the ability of Pseudomonas fluorescens, the specific spoilage organism (SSO) of turbot, to response to environmental signaling molecules remains unclear. This study investigated the effects of six synthetic N-acyl homoserine lactones (AHLs) on typical behaviors mediated by QS in P. fluorescens, such as biofilm formation and extracellular protease activity. Total volatile basic nitrogen (TVB-N) was used as a spoilage indicator to evaluate quality changes in AHL-treated turbot filets during storage. The results confirm the enhancing effect of environmental AHLs on QS-dependent factors of P. fluorescens and quality deterioration of turbot filets, with C4-HSL and C14-HSL being the most effective. Moreover, the content decrease of exogenous AHLs was also validated by gas chromatography–mass spectrometry analysis. Further, changes in rhlR transcription levels in P. fluorescens suggest that this bacterium can sense environmental AHLs. Finally, molecular docking analysis demonstrates the potential interactions of RhlR protein with various exogenous AHLs. These findings strongly implicate environmental AHLs in turbot spoilage caused by P. fluorescens, suggesting preservation of turbot should not exclusively consider the elimination of SSO-secreted AHLs.
Collapse
Affiliation(s)
- Tingting Li
- Key Laboratory of Biotechnology and Bioresources Utilization, Ministry of Education, Dalian Minzu University, Dalian, China
| | - Dangfeng Wang
- College of Food Science and Technology, Bohai University, National and Local Joint Engineering Research Center of Storage, Processing and Safety Control Technology for Fresh Agricultural and Aquatic Products, Jinzhou, China
| | - Likun Ren
- College of Food Science and Technology, Bohai University, National and Local Joint Engineering Research Center of Storage, Processing and Safety Control Technology for Fresh Agricultural and Aquatic Products, Jinzhou, China
| | - Yongchao Mei
- College of Food Science and Technology, Bohai University, National and Local Joint Engineering Research Center of Storage, Processing and Safety Control Technology for Fresh Agricultural and Aquatic Products, Jinzhou, China
| | - Ting Ding
- College of Food Science and Technology, Bohai University, National and Local Joint Engineering Research Center of Storage, Processing and Safety Control Technology for Fresh Agricultural and Aquatic Products, Jinzhou, China.,School of Food Science and Technology, Jiangnan University, Wuxi, China
| | - Qiuying Li
- College of Food Science and Technology, Bohai University, National and Local Joint Engineering Research Center of Storage, Processing and Safety Control Technology for Fresh Agricultural and Aquatic Products, Jinzhou, China
| | - Haitao Chen
- Beijing Key Laboratory of Flavor Chemistry, Beijing Technology and Business University, Beijing, China
| | - Jianrong Li
- College of Food Science and Technology, Bohai University, National and Local Joint Engineering Research Center of Storage, Processing and Safety Control Technology for Fresh Agricultural and Aquatic Products, Jinzhou, China
| |
Collapse
|
95
|
Li T, Wang D, Ren L, Mei Y, Ding T, Li Q, Chen H, Li J. Involvement of Exogenous N-Acyl-Homoserine Lactones in Spoilage Potential of Pseudomonas fluorescens Isolated From Refrigerated Turbot. Front Microbiol 2019; 10:2716. [PMID: 31849873 DOI: 10.3389/fmicb.2019.0271610.3389/fmicb.2019.02716.s001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 11/08/2019] [Indexed: 05/28/2023] Open
Abstract
Some bacteria can modulate their spoilage potential by responding to environmental signaling molecules via the quorum sensing (QS) system. However, the ability of Pseudomonas fluorescens, the specific spoilage organism (SSO) of turbot, to response to environmental signaling molecules remains unclear. This study investigated the effects of six synthetic N-acyl homoserine lactones (AHLs) on typical behaviors mediated by QS in P. fluorescens, such as biofilm formation and extracellular protease activity. Total volatile basic nitrogen (TVB-N) was used as a spoilage indicator to evaluate quality changes in AHL-treated turbot filets during storage. The results confirm the enhancing effect of environmental AHLs on QS-dependent factors of P. fluorescens and quality deterioration of turbot filets, with C4-HSL and C14-HSL being the most effective. Moreover, the content decrease of exogenous AHLs was also validated by gas chromatography-mass spectrometry analysis. Further, changes in rhlR transcription levels in P. fluorescens suggest that this bacterium can sense environmental AHLs. Finally, molecular docking analysis demonstrates the potential interactions of RhlR protein with various exogenous AHLs. These findings strongly implicate environmental AHLs in turbot spoilage caused by P. fluorescens, suggesting preservation of turbot should not exclusively consider the elimination of SSO-secreted AHLs.
Collapse
Affiliation(s)
- Tingting Li
- Key Laboratory of Biotechnology and Bioresources Utilization, Ministry of Education, Dalian Minzu University, Dalian, China
| | - Dangfeng Wang
- College of Food Science and Technology, Bohai University, National and Local Joint Engineering Research Center of Storage, Processing and Safety Control Technology for Fresh Agricultural and Aquatic Products, Jinzhou, China
| | - Likun Ren
- College of Food Science and Technology, Bohai University, National and Local Joint Engineering Research Center of Storage, Processing and Safety Control Technology for Fresh Agricultural and Aquatic Products, Jinzhou, China
| | - Yongchao Mei
- College of Food Science and Technology, Bohai University, National and Local Joint Engineering Research Center of Storage, Processing and Safety Control Technology for Fresh Agricultural and Aquatic Products, Jinzhou, China
| | - Ting Ding
- College of Food Science and Technology, Bohai University, National and Local Joint Engineering Research Center of Storage, Processing and Safety Control Technology for Fresh Agricultural and Aquatic Products, Jinzhou, China
- School of Food Science and Technology, Jiangnan University, Wuxi, China
| | - Qiuying Li
- College of Food Science and Technology, Bohai University, National and Local Joint Engineering Research Center of Storage, Processing and Safety Control Technology for Fresh Agricultural and Aquatic Products, Jinzhou, China
| | - Haitao Chen
- Beijing Key Laboratory of Flavor Chemistry, Beijing Technology and Business University, Beijing, China
| | - Jianrong Li
- College of Food Science and Technology, Bohai University, National and Local Joint Engineering Research Center of Storage, Processing and Safety Control Technology for Fresh Agricultural and Aquatic Products, Jinzhou, China
| |
Collapse
|
96
|
Biofilms facilitate cheating and social exploitation of β-lactam resistance in Escherichia coli. NPJ Biofilms Microbiomes 2019; 5:36. [PMID: 31814991 PMCID: PMC6884583 DOI: 10.1038/s41522-019-0109-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 10/30/2019] [Indexed: 11/27/2022] Open
Abstract
Gram-negative bacteria such as Escherichia coli commonly resist β-lactam antibiotics using plasmid-encoded β-lactamase enzymes. Bacterial strains that express β-lactamases have been found to detoxify liquid cultures and thus to protect genetically susceptible strains, constituting a clear laboratory example of social protection. These results are not necessarily general; on solid media, for instance, the rapid bactericidal action of β-lactams largely prevents social protection. Here, we tested the hypothesis that the greater tolerance of biofilm bacteria for β-lactams would facilitate social interactions. We used a recently isolated E. coli strain, capable of strong biofilm formation, to compare how cooperation and exploitation in colony biofilms and broth culture drives the dynamics of a non-conjugative plasmid encoding a clinically important β-lactamase. Susceptible cells in biofilms were tolerant of ampicillin—high doses and several days of exposure were required to kill them. In support of our hypothesis, we found robust social protection of susceptible E. coli in biofilms, despite fine-scale physical separation of resistant and susceptible cells and lower rates of production of extracellular β-lactamase. In contrast, social interactions in broth were restricted to a relatively narrow range of ampicillin doses. Our results show that β-lactam selection pressure on Gram-negative biofilms leads to cooperative resistance characterized by a low equilibrium frequency of resistance plasmids, sufficient to protect all cells.
Collapse
|
97
|
Yan H, Asfahl KL, Li N, Sun F, Xiao J, Shen D, Dandekar AA, Wang M. Conditional quorum-sensing induction of a cyanide-insensitive terminal oxidase stabilizes cooperating populations of Pseudomonas aeruginosa. Nat Commun 2019; 10:4999. [PMID: 31676850 PMCID: PMC6825135 DOI: 10.1038/s41467-019-13013-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 10/16/2019] [Indexed: 11/17/2022] Open
Abstract
Pseudomonas aeruginosa, an opportunistic pathogen of humans, uses quorum sensing (QS) to regulate the production of extracellular products that can benefit all members of the population. P. aeruginosa can police QS-deficient cheaters by producing hydrogen cyanide, which is also QS regulated; however, the mechanism by which cooperators selectively protect themselves from the toxicity of cyanide remained unresolved. Here, we show that a cyanide-insensitive terminal oxidase encoded by cioAB provides resistance to cyanide, but only in QS-proficient strains. QS-deficient cheaters do not activate cioAB transcription. QS-mediated regulation of cioAB expression depends on production of both cyanide by cooperators (which is QS regulated) and reactive oxygen species (ROS) from cheaters (which is not QS regulated). This type of regulatory system allows cooperating populations to respond, via ROS, to the presence of cheaters, and might allow them to defer the substantial metabolic cost of policing until cheaters are present in the population. Quorum sensing (QS) regulates production of ‘public goods’ by Pseudomonas aeruginosa, which releases toxic hydrogen cyanide to constrain QS-deficient cheaters. Here, Yan et al. show that QS-proficient strains protect themselves by producing a cyanide-insensitive enzyme in response to reactive oxygen species released by cheaters.
Collapse
Affiliation(s)
- Huicong Yan
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, China.,Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Hangzhou, China
| | - Kyle L Asfahl
- Department of Medicine, University of Washington, Seattle, WA, USA
| | - Na Li
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, China.,Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Hangzhou, China
| | - Feng Sun
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, China.,Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Hangzhou, China
| | - Junwei Xiao
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, China.,Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Hangzhou, China
| | - Dongsheng Shen
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, China.,Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Hangzhou, China
| | - Ajai A Dandekar
- Department of Medicine, University of Washington, Seattle, WA, USA. .,Department of Microbiology, University of Washington, Seattle, WA, USA.
| | - Meizhen Wang
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, China. .,Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Hangzhou, China.
| |
Collapse
|
98
|
Loarca D, Díaz D, Quezada H, Guzmán-Ortiz AL, Rebollar-Ruiz A, Presas AMF, Ramírez-Peris J, Franco-Cendejas R, Maeda T, Wood TK, García-Contreras R. Seeding Public Goods Is Essential for Maintaining Cooperation in Pseudomonas aeruginosa. Front Microbiol 2019; 10:2322. [PMID: 31649653 PMCID: PMC6794470 DOI: 10.3389/fmicb.2019.02322] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 09/23/2019] [Indexed: 01/29/2023] Open
Abstract
Quorum sensing in Pseudomonas aeruginosa controls the production of costly public goods such as exoproteases. This cooperative behavior is susceptible to social cheating by mutants that do not invest in the exoprotease production but assimilate the amino acids and peptides derived by the hydrolysis of proteins in the extracellular media. In sequential cultures with protein as the sole carbon source, these social cheaters are readily selected and often reach equilibrium with the exoprotease producers. Nevertheless, an excess of cheaters causes the collapse of population growth. In this work, using the reference strain PA14 and a clinical isolate from a burn patient, we demonstrate that the initial amount of public goods (exoprotease) that comes with the inoculum in each sequential culture is essential for maintaining population growth and that eliminating the exoprotease in the inoculum leads to rapid population collapse. Therefore, our results suggest that sequential washes should be combined with public good inhibitors to more effectively combat P. aeruginosa infections.
Collapse
Affiliation(s)
- Daniel Loarca
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Dánae Díaz
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Héctor Quezada
- Laboratorio de Investigación en Inmunología y Proteómica, Hospital Infantil de México Federico Gómez, Mexico City, Mexico
| | - Ana Laura Guzmán-Ortiz
- Laboratorio de Investigación en Inmunología y Proteómica, Hospital Infantil de México Federico Gómez, Mexico City, Mexico
| | - Abril Rebollar-Ruiz
- Escuela Superior de Medicina, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Ana María Fernández Presas
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Jimena Ramírez-Peris
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico.,Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Mexico City, Mexico
| | - Rafael Franco-Cendejas
- División de Infectología, Instituto Nacional de Rehabilitación Luis Guillermo Ibarra Ibarra, Mexico City, Mexico
| | - Toshinari Maeda
- Department of Biological Functions Engineering, Graduate School of Life Sciences and Systems Engineering, Kyushu Institute of Technology, Kitakyushu, Japan
| | - Thomas K Wood
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, United States
| | - Rodolfo García-Contreras
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| |
Collapse
|
99
|
Luu TQ, Hong Truong PN, Zitzmann K, Nguyen KT. Effects of Ultrafine Bubbles on Gram-Negative Bacteria: Inhibition or Selection? LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:13761-13768. [PMID: 31553189 DOI: 10.1021/acs.langmuir.9b02641] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Ultrafine bubbles exist in all liquids and are naturally stable. As their properties are not entirely known, it is unclear how they impact the surrounding solution and comparable-sized particles within it. It is essential to further investigate the properties of ultrafine bubbles in order to expand their industrial application. In this regard, the effect of ultrafine bubbles on bacterial development is of particular interest. Our current study, using optical density measurements and fluorescence microscopic images has demonstrated that ultrafine gas bubbles impact the morphology and phenotype of Escherichia coli and Pseudomonas aeruginosa. Specifically, Fourier transform infrared spectroscopic measurements indicated a thickening of bacterial membranes in samples exposed to ultrafine bubbles. The study also confirmed that ultrafine bubbles can inhibit bacterial cell growth. This study signifies the role of surface phenomena in bacterial culture, which is crucial in the upstream processes of recombinant DNA technology applications.
Collapse
Affiliation(s)
- Trong Quan Luu
- School of Biotechnology, International University , Viet Nam National University , Ho Chi Minh City 700,000 , Vietnam
| | - Phung Ngoc Hong Truong
- School of Biotechnology, International University , Viet Nam National University , Ho Chi Minh City 700,000 , Vietnam
| | - Kim Zitzmann
- College of Science , University College Dublin , Belfield, Dublin 4 D04 V1W8 , Ireland
| | - Khoi Tan Nguyen
- School of Biotechnology, International University , Viet Nam National University , Ho Chi Minh City 700,000 , Vietnam
- School of Chemical Engineering , The University of Queensland , Brisbane , Queensland 4072 , Australia
| |
Collapse
|
100
|
Rebolleda-Gómez M, Wood CW. Unclear Intentions: Eavesdropping in Microbial and Plant Systems. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00385] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|