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Batista BB, de Lima VM, Picinato BA, Koide T, da Silva Neto JF. A quorum-sensing regulatory cascade for siderophore-mediated iron homeostasis in Chromobacterium violaceum. mSystems 2024; 9:e0139723. [PMID: 38501880 PMCID: PMC11019928 DOI: 10.1128/msystems.01397-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Accepted: 02/24/2024] [Indexed: 03/20/2024] Open
Abstract
Iron is a transition metal used as a cofactor in many biochemical reactions. In bacteria, iron homeostasis involves Fur-mediated de-repression of iron uptake systems, such as the iron-chelating compounds siderophores. In this work, we identified and characterized novel regulatory systems that control siderophores in the environmental opportunistic pathogen Chromobacterium violaceum. Screening of a 10,000-transposon mutant library for siderophore halos identified seven possible regulatory systems involved in siderophore-mediated iron homeostasis in C. violaceum. Further characterization revealed a regulatory cascade that controls siderophores involving the transcription factor VitR acting upstream of the quorum-sensing (QS) system CviIR. Mutation of the regulator VitR led to an increase in siderophore halos, and a decrease in biofilm, violacein, and protease production. We determined that these effects occurred due to VitR-dependent de-repression of vioS. Increased VioS leads to direct inhibition of the CviR regulator by protein-protein interaction. Indeed, insertion mutations in cviR and null mutations of cviI and cviR led to an increase of siderophore halos. RNA-seq of the cviI and cviR mutants revealed that CviR regulates CviI-dependent and CviI-independent regulons. Classical QS-dependent processes (violacein, proteases, and antibiotics) were activated at high cell density by both CviI and CviR. However, genes related to iron homeostasis and many other processes were regulated by CviR but not CviI, suggesting that CviR acts without its canonical CviI autoinducer. Our data revealed a complex regulatory cascade involving QS that controls siderophore-mediated iron homeostasis in C. violaceum.IMPORTANCEThe iron-chelating compounds siderophores play a major role in bacterial iron acquisition. Here, we employed a genetic screen to identify novel siderophore regulatory systems in Chromobacterium violaceum, an opportunistic human pathogen. Many mutants with increased siderophore halos had transposon insertions in genes encoding transcription factors, including a novel regulator called VitR, and CviR, the regulator of the quorum-sensing (QS) system CviIR. We found that VitR is upstream in the pathway and acts as a dedicated repressor of vioS, which encodes a direct CviR-inhibitory protein. Indeed, all QS-related phenotypes of a vitR mutant were rescued in a vitRvioS mutant. At high cell density, CviIR activated classical QS-dependent processes (violacein, proteases, and antibiotics production). However, genes related to iron homeostasis and type-III and type-VI secretion systems were regulated by CviR in a CviI- or cell density-independent manner. Our data unveil a complex regulatory cascade integrating QS and siderophores in C. violaceum.
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Affiliation(s)
- Bianca B. Batista
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Vinicius M. de Lima
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Beatriz A. Picinato
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Tie Koide
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - José F. da Silva Neto
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
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Czárán T, Scheuring I, Zachar I, Számadó S. Cue-driven microbial cooperation and communication: evolving quorum sensing with honest signaling. BMC Biol 2024; 22:73. [PMID: 38561772 PMCID: PMC10986144 DOI: 10.1186/s12915-024-01857-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Accepted: 02/28/2024] [Indexed: 04/04/2024] Open
Abstract
BACKGROUND Quorum sensing (QS) is the ability of microorganisms to assess local clonal density by measuring the extracellular concentration of signal molecules that they produce and excrete. QS is also the only known way of bacterial communication that supports the coordination of within-clone cooperative actions requiring a certain threshold density of cooperating cells. Cooperation aided by QS communication is sensitive to cheating in two different ways: laggards may benefit from not investing in cooperation but enjoying the benefit provided by their cooperating neighbors, whereas Liars explicitly promise cooperation but fail to do so, thereby convincing potential cooperating neighbors to help them, for almost free. Given this double vulnerability to cheats, it is not trivial why QS-supported cooperation is so widespread among prokaryotes. RESULTS We investigated the evolutionary dynamics of QS in populations of cooperators for whom the QS signal is an inevitable side effect of producing the public good itself (cue-based QS). Using spatially explicit agent-based lattice simulations of QS-aided threshold cooperation (whereby cooperation is effective only above a critical cumulative level of contributions) and three different (analytical and numerical) approximations of the lattice model, we explored the dynamics of QS-aided threshold cooperation under a feasible range of parameter values. We demonstrate three major advantages of cue-driven cooperation. First, laggards cannot wipe out cooperation under a wide range of reasonable environmental conditions, in spite of an unconstrained possibility to mutate to cheating; in fact, cooperators may even exclude laggards at high cooperation thresholds. Second, lying almost never pays off, if the signal is an inevitable byproduct (i.e., the cue) of cooperation; even very cheap fake signals are selected against. And thirdly, QS is most useful if local cooperator densities are the least predictable, i.e., if their lattice-wise mean is close to the cooperation threshold with a substantial variance. CONCLUSIONS Comparing the results of the four different modeling approaches indicates that cue-driven threshold cooperation may be a viable evolutionary strategy for microbes that cannot keep track of past behavior of their potential cooperating partners, in spatially viscous and in well-mixed environments alike. Our model can be seen as a version of the famous greenbeard effect, where greenbeards coexist with defectors in a evolutionarily stable polymorphism. Such polymorphism is maintained by the condition-dependent trade-offs of signal production which are characteristic of cue-based QS.
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Affiliation(s)
- Tamás Czárán
- Institute of Evolution, Centre for Ecological Research, HUN-REN, Konkoly-Thege Miklós Út 29-33, 1121, Budapest, Hungary
| | - István Scheuring
- Institute of Evolution, Centre for Ecological Research, HUN-REN, Konkoly-Thege Miklós Út 29-33, 1121, Budapest, Hungary
| | - István Zachar
- Institute of Evolution, Centre for Ecological Research, HUN-REN, Konkoly-Thege Miklós Út 29-33, 1121, Budapest, Hungary
- Department of Plant Systematics, Ecology and Theoretical Biology, Eötvös Lóránd University, Pázmány Péter st. 1/c, 1117, Budapest, Hungary
| | - Szabolcs Számadó
- Department of Sociology and Communication, Budapest University of Technology and Economics, Egry J. U. 1, Budapest, 1111, Hungary.
- Centre for Social Science, Lendület Research Group, HUN-REN, CSS-RECENS, Tóth Kálmán U. 4, 1097, Budapest, Hungary.
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Niggli S, Schwyter L, Poveda L, Grossmann J, Kümmerli R. Rapid and strain-specific resistance evolution of Staphylococcus aureus against inhibitory molecules secreted by Pseudomonas aeruginosa. mBio 2023; 14:e0315322. [PMID: 37646506 PMCID: PMC10653847 DOI: 10.1128/mbio.03153-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 06/30/2023] [Indexed: 09/01/2023] Open
Abstract
IMPORTANCE Polymicrobial infections are common. In chronic infections, the different pathogens may repeatedly interact, which could spur evolutionary dynamics with pathogens adapting to one another. Here, we explore the potential of Staphylococcus aureus to adapt to its competitor Pseudomonas aeruginosa. These two pathogens frequently co-occur, and P. aeruginosa is seen as the dominant species being able to displace S. aureus. We studied three different S. aureus strains and found that all became quickly resistant to inhibitory compounds secreted by P. aeruginosa. Our experimental evolution revealed strains-specific adaptations with three main factors contributing to resistance evolution: (i) overproduction of staphyloxanthin, a molecule protecting from oxidative stress; (ii) the formation of small colony variants also protecting from oxidative stress; and (iii) alterations of membrane transporters possibly reducing toxin uptake. Our results show that species interactions can change over time potentially favoring species co-existence, which in turn could affect disease progression and treatment options.
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Affiliation(s)
- Selina Niggli
- Department of Quantitative Biomedicine, University of Zurich, Winterthurerstrasse, Zurich, Switzerland
| | - Lukas Schwyter
- Department of Quantitative Biomedicine, University of Zurich, Winterthurerstrasse, Zurich, Switzerland
| | - Lucy Poveda
- Functional Genomics Center Zurich, ETH Zurich and University of Zurich, Winterthurerstrasse, Zurich, Switzerland
- Swiss Institute of Bioinformatics (SIB) Quartier Sorge-Batiment Amphipole, Lausanne, Switzerland
| | - Jonas Grossmann
- Functional Genomics Center Zurich, ETH Zurich and University of Zurich, Winterthurerstrasse, Zurich, Switzerland
- Swiss Institute of Bioinformatics (SIB) Quartier Sorge-Batiment Amphipole, Lausanne, Switzerland
| | - Rolf Kümmerli
- Department of Quantitative Biomedicine, University of Zurich, Winterthurerstrasse, Zurich, Switzerland
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Ogbechi J, Huang YS, Clanchy FIL, Pantazi E, Topping LM, Darlington LG, Williams RO, Stone TW. Modulation of immune cell function, IDO expression and kynurenine production by the quorum sensor 2-heptyl-3-hydroxy-4-quinolone (PQS). Front Immunol 2022; 13:1001956. [PMID: 36389710 PMCID: PMC9650388 DOI: 10.3389/fimmu.2022.1001956] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Accepted: 10/05/2022] [Indexed: 12/29/2023] Open
Abstract
Many invasive micro-organisms produce 'quorum sensor' molecules which regulate colony expansion and may modulate host immune responses. We have examined the ability of Pseudomonas Quorum Sensor (PQS) to influence cytokine expression under conditions of inflammatory stress. The administration of PQS in vivo to mice with collagen-induced arthritis (CIA) increased the severity of disease. Blood and inflamed paws from treated mice had fewer regulatory T cells (Tregs) but normal numbers of Th17 cells. However, PQS (1μM) treatment of antigen-stimulated lymph node cells from collagen-immunised mice in vitro inhibited the differentiation of CD4+IFNγ+ cells, with less effect on CD4+IL-17+ cells and no change in CD4+FoxP3+Tregs. PQS also inhibited T cell activation by anti-CD3/anti-CD28 antibodies. PQS reduced murine macrophage polarisation and inhibited expression of IL1B and IL6 genes in murine macrophages and human THP-1 cells. In human monocyte-derived macrophages, IDO1 gene, protein and enzyme activity were all inhibited by exposure to PQS. TNF gene expression was inhibited in THP-1 cells but not murine macrophages, while LPS-induced TNF protein release was increased by high PQS concentrations. PQS is known to have iron scavenging activity and its suppression of cytokine release was abrogated by iron supplementation. Unexpectedly, PQS decreased the expression of indoleamine-2, 3-dioxygenase genes (IDO1 and IDO2), IDO1 protein expression and enzyme activity in mouse and human macrophages. This is consistent with evidence that IDO1 inhibition or deletion exacerbates arthritis, while kynurenine reduces its severity. It is suggested that the inhibition of IDO1 and cytokine expression may contribute to the quorum sensor and invasive actions of PQS.
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Affiliation(s)
- Joy Ogbechi
- The Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics, Rheumatology and Musculo-skeletal Sciences (NDORMS), University of Oxford, Oxford, United Kingdom
| | - Yi-Shu Huang
- The Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics, Rheumatology and Musculo-skeletal Sciences (NDORMS), University of Oxford, Oxford, United Kingdom
| | - Felix I. L. Clanchy
- The Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics, Rheumatology and Musculo-skeletal Sciences (NDORMS), University of Oxford, Oxford, United Kingdom
| | - Eirini Pantazi
- The Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics, Rheumatology and Musculo-skeletal Sciences (NDORMS), University of Oxford, Oxford, United Kingdom
| | - Louise M. Topping
- The Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics, Rheumatology and Musculo-skeletal Sciences (NDORMS), University of Oxford, Oxford, United Kingdom
| | | | - Richard O. Williams
- The Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics, Rheumatology and Musculo-skeletal Sciences (NDORMS), University of Oxford, Oxford, United Kingdom
| | - Trevor W. Stone
- The Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics, Rheumatology and Musculo-skeletal Sciences (NDORMS), University of Oxford, Oxford, United Kingdom
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Díaz-Pérez SP, Solis CS, López-Bucio JS, Valdez Alarcón JJ, Villegas J, Reyes-De la Cruz H, Campos-Garcia J. Pathogenesis in Pseudomonas aeruginosa PAO1 Biofilm-Associated Is Dependent on the Pyoverdine and Pyocyanin Siderophores by Quorum Sensing Modulation. MICROBIAL ECOLOGY 2022:10.1007/s00248-022-02095-5. [PMID: 35948833 DOI: 10.1007/s00248-022-02095-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 07/29/2022] [Indexed: 06/15/2023]
Abstract
Pseudomonas aeruginosa is an opportunistic pathogenic bacterium for humans, animals, and plants, through producing different molecular factors such as biofilm, siderophores, and other virulence factors which favor bacterial establishment and infection in the host. In P. aeruginosa PAO1, the production of these factors is regulated by the bacterial quorum sensing (QS) mechanisms. From them, siderophores are involved in iron acquisition, transport, and homeostasis. They are also considered some of the main virulence factors in P. aeruginosa; however, detailed mechanisms to induce bacterial pathogenesis are poorly understood. In this work, through reverse genetics, we evaluated the function of bacterial pathogenesis in the pvd cluster genes, which are required for synthesizing the siderophore pyoverdine (PVD). Single pvdI, pvdJ, pvdL, and double mutant strains were analyzed, and contrary to expected, the pvdL and pvdI mutations increased the concentration of PVD and other phenazines, such as pyocyanin (PYO) and phenazine-1-carboxylic acid (PCA) and also an increased biofilm production and morphology depending on the autoinducer 2-alkyl-4-quinolone (PQS) and the QS molecules acyl-homoserine lactones. Consequently, in the in vivo pathogenicity model of Caenorhabditis elegans, the mutations in pvdI, pvdJ, and pvdL increased the survival of the worms exposed to supernatants or biofilms of the bacterial cultures. However, the double mutant pvdI/pvdJ increased its toxicity in agreeing with the biofilm production, PVD, PYO, and PCA. The findings indicate that the mutations in pvd genes encode non-ribosomal peptide synthetases impacted the biofilm's structure, but suppressively also of the phenazines, confirming that the siderophores contribute to the bacterial establishment and pathogenicity of P. aeruginosa PAO1.
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Affiliation(s)
- Sharel Pamela Díaz-Pérez
- Laboratorio de Biotecnología Microbiana, Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edif. U-3, Ciudad Universitaria, CP. 58030, Morelia, Michoacán, México
| | - Christian Said Solis
- Laboratorio de Biotecnología Microbiana, Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edif. U-3, Ciudad Universitaria, CP. 58030, Morelia, Michoacán, México
| | - Jesús Salvador López-Bucio
- Laboratorio de Control Traduccional, Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Michoacán, Mexico
| | - Juan J Valdez Alarcón
- Centro de Estudios Multidisciplinarios en Biotecnología, Universidad Michoacana de San Nicolás de Hidalgo, Tarímbaro, Michoacán, México
| | - Javier Villegas
- Laboratorio de Interacción Suelo, Planta, Microorganismo, Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Michoacán, Mexico
| | - Homero Reyes-De la Cruz
- Laboratorio de Control Traduccional, Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Michoacán, Mexico
| | - Jesús Campos-Garcia
- Laboratorio de Biotecnología Microbiana, Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edif. U-3, Ciudad Universitaria, CP. 58030, Morelia, Michoacán, México.
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6
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Hills OJ, Yong CW, Scott AJ, Devine DA, Smith J, Chappell HF. Atomic-scale interactions between quorum sensing autoinducer molecules and the mucoid P. aeruginosa exopolysaccharide matrix. Sci Rep 2022; 12:7724. [PMID: 35545629 PMCID: PMC9095684 DOI: 10.1038/s41598-022-11499-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 04/18/2022] [Indexed: 12/22/2022] Open
Abstract
Mucoid Pseudomonas aeruginosa is a prevalent cystic fibrosis (CF) lung coloniser whose chronicity is associated with the formation of cation cross-linked exopolysaccharide (EPS) matrices, which form a biofilm that acts as a diffusion barrier, sequestering cationic and neutral antimicrobials, and making it extremely resistant to pharmacological challenge. Biofilm chronicity and virulence of the colony is regulated by quorum sensing autoinducers (QSAIs), small signalling metabolites that pass between bacteria, through the biofilm matrix, regulating genetic responses on a population-wide scale. The nature of how these molecules interact with the EPS is poorly understood, despite the fact that they must pass through EPS matrix to reach neighbouring bacteria. Interactions at the atomic-scale between two QSAI molecules, C4-HSL and PQS—both utilised by mucoid P. aeruginosa in the CF lung—and the EPS, have been studied for the first time using a combined molecular dynamics (MD) and density functional theory (DFT) approach. A large-scale, calcium cross-linked, multi-chain EPS molecular model was developed and MD used to sample modes of interaction between QSAI molecules and the EPS that occur at physiological equilibrium. The thermodynamic stability of the QSAI-EPS adducts were calculated using DFT. These simulations provide a thermodynamic rationale for the apparent free movement of C4-HSL, highlight key molecular functionality responsible for EPS binding and, based on its significantly reduced mobility, suggest PQS as a viable target for quorum quenching.
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Affiliation(s)
- Oliver J Hills
- School of Food Science & Nutrition, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK.
| | - Chin W Yong
- Daresbury Laboratory, Scientific Computing Department, Science and Technology Facilities Council, Keckwick Lane, Daresbury, Warrington, WA4 4AD, UK.,Division of Pharmacy and Optometry, School of Health Sciences, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Andrew J Scott
- School of Chemical & Process Engineering, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
| | - Deirdre A Devine
- School of Dentistry, University of Leeds, Clarendon Way, Leeds, LS2 9LU, UK
| | - James Smith
- School of Food Science & Nutrition, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
| | - Helen F Chappell
- School of Food Science & Nutrition, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK.
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7
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Mridha S, Kümmerli R. Enforced specialization fosters mutual cheating and not division of labour in the bacterium Pseudomonas aeruginosa. J Evol Biol 2022; 35:719-730. [PMID: 35380743 PMCID: PMC9323447 DOI: 10.1111/jeb.14001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Revised: 10/24/2021] [Accepted: 02/21/2022] [Indexed: 11/30/2022]
Abstract
A common way for bacteria to cooperate is via the secretion of beneficial public goods (proteases, siderophores, biosurfactants) that can be shared amongst individuals in a group. Bacteria often simultaneously deploy multiple public goods with complementary functions. This raises the question whether natural selection could favour division of labour where subpopulations or species specialize in the production of a single public good, whilst sharing the complementary goods at the group level. Here we use an experimental system, where we mix engineered specialists of the bacterium Pseudomonas aeruginosa that can each only produce one of the two siderophores, pyochelin or pyoverdine and explore the conditions under which specialization can lead to division of labour. When growing pyochelin and pyoverdine specialists at different mixing ratios under different levels of iron limitation, we found that specialists could only successfully complement each other in environments with moderate iron limitation and grow as good as the generalist wildtype but not better. Under more stringent iron limitation, the dynamics in specialist communities was characterized by mutual cheating and with higher proportions of pyochelin producers greatly compromising group productivity. Nonetheless, specialist communities remained stable through negative frequency‐dependent selection. Our work shows that specialization in a bacterial community can be spurred by cheating and does not necessarily result in beneficial division of labour. We propose that natural selection might favour fine‐tuned regulatory mechanisms in generalists over division of labour because the former enables generalists to remain flexible and adequately adjust public good investments in fluctuating environments.
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Affiliation(s)
- Subham Mridha
- Department of Quantitative Biomedicine, University of Zurich, Zurich, Switzerland
| | - Rolf Kümmerli
- Department of Quantitative Biomedicine, University of Zurich, Zurich, Switzerland
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Periodically Disturbing the Spatial Structure of Biofilms Can Affect the Production of an Essential Virulence Factor in Pseudomonas aeruginosa. mSystems 2021; 6:e0096121. [PMID: 34581603 PMCID: PMC8547473 DOI: 10.1128/msystems.00961-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Understanding the environmental factors that affect the production of virulence factors has major implications in evolution and medicine. While spatial structure is important in virulence factor production, observations of this relationship have occurred in undisturbed or continuously disturbed environments. However, natural environments are subject to periodic fluctuations, including changes in physical forces, which could alter the spatial structure of bacterial populations and impact virulence factor production. Using Pseudomonas aeruginosa PA14, we periodically applied a physical force to biofilms and examined production of pyoverdine. Intermediate frequencies of disturbance reduced the amount of pyoverdine produced compared to undisturbed or frequently disturbed conditions. To explore the generality of this finding, we examined how an intermediate disturbance frequency affected pyoverdine production in 21 different strains of P. aeruginosa. Periodic disturbance increased, decreased, or did not change the amount of pyoverdine produced relative to undisturbed populations. Mathematical modeling predicts that interactions between pyoverdine synthesis rate and biofilm density determine the amount of pyoverdine synthesized. When the pyoverdine synthesis rates are high, depletion of the biofilm due to disturbance reduces the accumulation of pyoverdine. At intermediate synthesis rates, production of pyoverdine increases during disturbance as bacteria dispersed into the planktonic state enjoy increased growth and pyoverdine production rates. At low synthesis rates, disturbance does not alter the amount of pyoverdine produced since disturbance-driven access to nutrients does not augment pyoverdine synthesis. Our results suggest that environmental conditions shape robustness in the production of virulence factors and may lead to novel approaches to treat infections. IMPORTANCE Virulence factors are required to cause infections. Previous work has shown that the spatial organization of a population, such as a biofilm, can increase the production of some virulence factors, including pyoverdine, which is produced by Pseudomonas aeruginosa. Pyoverdine is essential for the infection process, and reducing its production can limit infections. We have discovered that periodically changing the spatial structure of a biofilm of P. aeruginosa strain PA14 using a physical force can reduce the production of pyoverdine. A mathematical model suggests that this is due to the disruption of spatial organization. Using additional strains of P. aeruginosa isolated from patients and the environment, we use experiments and modeling to show that this reduction in pyoverdine is due to interactions between biofilm density and the synthesis rate of pyoverdine. Our results identify conditions where pyoverdine production is reduced and may lead to novel ways to treat infections.
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Lindsay RJ, Jepson A, Butt L, Holder PJ, Smug BJ, Gudelj I. Would that it were so simple: Interactions between multiple traits undermine classical single-trait-based predictions of microbial community function and evolution. Ecol Lett 2021; 24:2775-2795. [PMID: 34453399 DOI: 10.1111/ele.13861] [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] [Received: 04/21/2021] [Revised: 06/11/2021] [Accepted: 07/27/2021] [Indexed: 12/15/2022]
Abstract
Understanding how microbial traits affect the evolution and functioning of microbial communities is fundamental for improving the management of harmful microorganisms, while promoting those that are beneficial. Decades of evolutionary ecology research has focused on examining microbial cooperation, diversity, productivity and virulence but with one crucial limitation. The traits under consideration, such as public good production and resistance to antibiotics or predation, are often assumed to act in isolation. Yet, in reality, multiple traits frequently interact, which can lead to unexpected and undesired outcomes for the health of macroorganisms and ecosystem functioning. This is because many predictions generated in a single-trait context aimed at promoting diversity, reducing virulence or controlling antibiotic resistance can fail for systems where multiple traits interact. Here, we provide a much needed discussion and synthesis of the most recent research to reveal the widespread and diverse nature of multi-trait interactions and their consequences for predicting and controlling microbial community dynamics. Importantly, we argue that synthetic microbial communities and multi-trait mathematical models are powerful tools for managing the beneficial and detrimental impacts of microbial communities, such that past mistakes, like those made regarding the stewardship of antimicrobials, are not repeated.
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Affiliation(s)
- Richard J Lindsay
- Biosciences and Living Systems Institute, University of Exeter, Exeter, UK
| | - Alys Jepson
- Biosciences and Living Systems Institute, University of Exeter, Exeter, UK
| | - Lisa Butt
- Biosciences and Living Systems Institute, University of Exeter, Exeter, UK
| | - Philippa J Holder
- Biosciences and Living Systems Institute, University of Exeter, Exeter, UK
| | - Bogna J Smug
- Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, Poland
| | - Ivana Gudelj
- Biosciences and Living Systems Institute, University of Exeter, Exeter, UK
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Genetic Network Architecture and Environmental Cues Drive Spatial Organization of Phenotypic Division of Labor in Streptomyces coelicolor. mBio 2021; 12:mBio.00794-21. [PMID: 34006658 PMCID: PMC8262882 DOI: 10.1128/mbio.00794-21] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A number of bacteria are known to differentiate into cells with distinct phenotypic traits during processes such as biofilm formation or the development of reproductive structures. These cell types, by virtue of their specialized functions, embody a division of labor. However, how bacteria build spatial patterns of differentiated cells is not well understood. Here, we examine the factors that drive spatial patterns in divisions of labor in colonies of Streptomyces coelicolor, a multicellular bacterium capable of synthesizing an array of antibiotics and forming complex reproductive structures (e.g., aerial hyphae and spores). Using fluorescent reporters, we demonstrate that the pathways for antibiotic biosynthesis and aerial hypha formation are activated in distinct waves of gene expression that radiate outwards in S. coelicolor colonies. We also show that the spatiotemporal separation of these cell types depends on a key activator in the developmental pathway, AdpA. Importantly, when we manipulated local gradients by growing competing microbes nearby, or through physical disruption, expression in these pathways could be decoupled and/or disordered, respectively. Finally, the normal spatial organization of these cell types was partially restored with the addition of a siderophore, a public good made by these organisms, to the growth medium. Together, these results indicate that spatial divisions of labor in S. coelicolor colonies are determined by a combination of physiological gradients and regulatory network architecture, key factors that also drive patterns of cellular differentiation in multicellular eukaryotic organisms.
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Biological and clinical significance of quorum sensing alkylquinolones: current analytical and bioanalytical methods for their quantification. Anal Bioanal Chem 2021; 413:4599-4618. [PMID: 33959788 DOI: 10.1007/s00216-021-03356-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 03/21/2021] [Accepted: 04/16/2021] [Indexed: 12/27/2022]
Abstract
Quorum sensing (QS) is a sophisticated bacterial communication system which plays a key role in the virulence and biofilm formation of many pathogens. The Pseudomonas aeruginosa QS network consists of four sets of connected systems (las, rlh, pqs and iqs) hierarchically organized. The pqs system involves characteristic autoinducers (AI), most of them sharing an alkylquinolone (AQ) structure, and is able to carry out several relevant biological functions besides its main signalling activity. Their role in bacterial physiology and pathogenicity has been widely studied. Indeed, the presence of these metabolites in several body fluids and infected tissues has pointed to their potential value as biomarkers of infection. In this review, we summarize the most recent findings about the biological implications and the clinical significance of the main P. aeruginosa AQs. These findings have encouraged the development of analytical and bioanalytical techniques addressed to assess the role of these metabolites in bacterial growth and survival, during pathogenesis or as biomarkers of infections. The availability of highly sensitive reliable analytical methods suitable for clinical analysis would allow getting knowledge about pathogenesis and disease prognosis or progression, supporting clinicians on the decision-making process for the management of these infections and guiding them on the application of more effective and appropriate treatments. The benefits from the implementation of the point-of-care (PoC)-type testing in infectious disease diagnostics, which are seen to improve patient outcomes by promoting earlier therapeutic interventions, are also discussed.
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12
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Montagut E, Martin-Gomez MT, Marco MP. An Immunochemical Approach to Quantify and Assess the Potential Value of the Pseudomonas Quinolone Signal as a Biomarker of Infection. Anal Chem 2021; 93:4859-4866. [PMID: 33691411 PMCID: PMC8479725 DOI: 10.1021/acs.analchem.0c04731] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 03/04/2021] [Indexed: 01/20/2023]
Abstract
Quorum sensing (QS) is a bacterial cell density-based communication system using low molecular weight signals called autoinducers (AIs). Identification and quantification of these molecules could provide valuable information related to the stage of colonization or infection as well as the stage of the disease. With this scenario, we report here for the first time the development of antibodies against the PQS (pseudomonas quinolone signal), the main signaling molecule from the pqs QS system of Pseudomonas aeruginosa, and the development of a microplate-based enzyme-linked immunosorbent assay (ELISA) able of quantifying this molecule in complex biological media in the low nanometer range (LOD, 0.36 ± 0.14 nM in culture broth media). Moreover, the PQS ELISA here reported has been found to be robust and reliable, providing accurate results in culture media. The technique allowed us to follow up the PQS profile of the release of bacterial clinical isolates obtained from patients of different disease status. A clear correlation was found between the PQS immunoreactivity equivalents and the chronic or acute infection conditions, which supports the reported differences on virulence and behavior of these bacterial strains due to their adaptation capability to the host environment. The results obtained point to the potential of the PQS as a biomarker of infection and to the value of the antibodies and the technology developed for improving diagnosis and management of P. aeruginosa infections based on the precise identification of the pathogen, appropriate stratification of the patients according to their disease status, and knowledge of the disease progression.
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Affiliation(s)
- Enrique
J. Montagut
- Nanobiotechnology
for Diagnostics (Nb4D), Department of Surfactants and Nanobiotechnology, Institute for Advanced Chemistry of Catalonia (IQAC)
of the Spanish Council for Scientific Research (CSIC), 08034 Barcelona, Spain
- CIBER
de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Jordi Girona 18-26, 08034 Barcelona, Spain
| | - M. Teresa Martin-Gomez
- Microbiology
Department, Vall d’Hebron University
Hospital (VHUH), 08035 Barcelona, Spain
- Genetics
and Microbiology Department, Universitat
Autònoma de Barcelona (UAB), 08193 Barcelona, Spain
| | - M. Pilar Marco
- Nanobiotechnology
for Diagnostics (Nb4D), Department of Surfactants and Nanobiotechnology, Institute for Advanced Chemistry of Catalonia (IQAC)
of the Spanish Council for Scientific Research (CSIC), 08034 Barcelona, Spain
- CIBER
de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Jordi Girona 18-26, 08034 Barcelona, Spain
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13
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Contrasting Role of Fungal Siderophore in Metal Ion Complex Formation. Fungal Biol 2021. [DOI: 10.1007/978-3-030-53077-8_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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14
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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.
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15
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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.
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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
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16
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Chatterjee P, Sass G, Swietnicki W, Stevens DA. Review of Potential Pseudomonas Weaponry, Relevant to the Pseudomonas-Aspergillus Interplay, for the Mycology Community. J Fungi (Basel) 2020; 6:jof6020081. [PMID: 32517271 PMCID: PMC7345761 DOI: 10.3390/jof6020081] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 06/03/2020] [Accepted: 06/03/2020] [Indexed: 12/15/2022] Open
Abstract
Pseudomonas aeruginosa is one of the most prominent opportunistic bacteria in airways of cystic fibrosis patients and in immunocompromised patients. These bacteria share the same polymicrobial niche with other microbes, such as the opportunistic fungus Aspergillus fumigatus. Their inter-kingdom interactions and diverse exchange of secreted metabolites are responsible for how they both fare in competition for ecological niches. The outcomes of their contests likely determine persistent damage and degeneration of lung function. With a myriad of virulence factors and metabolites of promising antifungal activity, P. aeruginosa products or their derivatives may prove useful in prophylaxis and therapy against A. fumigatus. Quorum sensing underlies the primary virulence strategy of P. aeruginosa, which serves as cell–cell communication and ultimately leads to the production of multiple virulence factors. Understanding the quorum-sensing-related pathogenic mechanisms of P. aeruginosa is a first step for understanding intermicrobial competition. In this review, we provide a basic overview of some of the central virulence factors of P. aeruginosa that are regulated by quorum-sensing response pathways and briefly discuss the hitherto known antifungal properties of these virulence factors. This review also addresses the role of the bacterial secretion machinery regarding virulence factor secretion and maintenance of cell–cell communication.
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Affiliation(s)
- Paulami Chatterjee
- California Institute for Medical Research, San Jose, CA 95128, USA; (P.C.); (G.S.)
| | - Gabriele Sass
- California Institute for Medical Research, San Jose, CA 95128, USA; (P.C.); (G.S.)
| | - Wieslaw Swietnicki
- Department of Immunology of Infectious Diseases, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, 50-114 Wroclaw, Poland;
| | - David A. Stevens
- California Institute for Medical Research, San Jose, CA 95128, USA; (P.C.); (G.S.)
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
- Correspondence: ; Tel.: +1-408-998-4554
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17
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Mukherji R, Zhang S, Chowdhury S, Stallforth P. Chimeric LuxR Transcription Factors Rewire Natural Product Regulation. Angew Chem Int Ed Engl 2020; 59:6192-6195. [PMID: 31943579 PMCID: PMC7187462 DOI: 10.1002/anie.201914449] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 12/12/2019] [Indexed: 01/17/2023]
Abstract
LuxR-type transcriptional activator proteins frequently regulate the expression of biosynthetic gene clusters (BGCs). With only a fraction of bacterial BGCs being expressed under standard culturing conditions, modulation of LuxRs would provide a powerful approach to activate silent clusters. We show that by exploiting the modular nature of LuxR proteins, it is possible to construct functional chimeric LuxRs, which enables both the rewiring of quorum sensing systems and the activation of silent BGCs. Importantly, our strategy allowed us to identify the novel natural product pseudomonol from a bacterium of the genus Pseudomonas.
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Affiliation(s)
- Ruchira Mukherji
- Independent Junior Research Group Chemistry of Microbial CommunicationLeibniz Institute for Natural Product Research and Infection BiologyHans Knöll Institute (HKI)Beutenbergstrasse 11a07745JenaGermany
| | - Shuaibing Zhang
- Independent Junior Research Group Chemistry of Microbial CommunicationLeibniz Institute for Natural Product Research and Infection BiologyHans Knöll Institute (HKI)Beutenbergstrasse 11a07745JenaGermany
| | - Somak Chowdhury
- Independent Junior Research Group Chemistry of Microbial CommunicationLeibniz Institute for Natural Product Research and Infection BiologyHans Knöll Institute (HKI)Beutenbergstrasse 11a07745JenaGermany
| | - Pierre Stallforth
- Independent Junior Research Group Chemistry of Microbial CommunicationLeibniz Institute for Natural Product Research and Infection BiologyHans Knöll Institute (HKI)Beutenbergstrasse 11a07745JenaGermany
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18
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Mukherji R, Zhang S, Chowdhury S, Stallforth P. Chimeric LuxR Transcription Factors Rewire Natural Product Regulation. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201914449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Ruchira Mukherji
- Independent Junior Research Group Chemistry of Microbial CommunicationLeibniz Institute for Natural Product Research and Infection BiologyHans Knöll Institute (HKI) Beutenbergstrasse 11a 07745 Jena Germany
| | - Shuaibing Zhang
- Independent Junior Research Group Chemistry of Microbial CommunicationLeibniz Institute for Natural Product Research and Infection BiologyHans Knöll Institute (HKI) Beutenbergstrasse 11a 07745 Jena Germany
| | - Somak Chowdhury
- Independent Junior Research Group Chemistry of Microbial CommunicationLeibniz Institute for Natural Product Research and Infection BiologyHans Knöll Institute (HKI) Beutenbergstrasse 11a 07745 Jena Germany
| | - Pierre Stallforth
- Independent Junior Research Group Chemistry of Microbial CommunicationLeibniz Institute for Natural Product Research and Infection BiologyHans Knöll Institute (HKI) Beutenbergstrasse 11a 07745 Jena Germany
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19
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Gestal MC, Howard LK, Dewan K, Johnson HM, Barbier M, Bryant C, Soumana IH, Rivera I, Linz B, Blas-Machado U, Harvill ET. Enhancement of immune response against Bordetella spp. by disrupting immunomodulation. Sci Rep 2019; 9:20261. [PMID: 31889098 PMCID: PMC6937331 DOI: 10.1038/s41598-019-56652-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 12/12/2019] [Indexed: 12/27/2022] Open
Abstract
Well-adapted pathogens must evade clearance by the host immune system and the study of how they do this has revealed myriad complex strategies and mechanisms. Classical bordetellae are very closely related subspecies that are known to modulate adaptive immunity in a variety of ways, permitting them to either persist for life or repeatedly infect the same host. Exploring the hypothesis that exposure to immune cells would cause bordetellae to induce expression of important immunomodulatory mechanisms, we identified a putative regulator of an immunomodulatory pathway. The deletion of btrS in B. bronchiseptica did not affect colonization or initial growth in the respiratory tract of mice, its natural host, but did increase activation of the inflammasome pathway, and recruitment of inflammatory cells. The mutant lacking btrS recruited many more B and T cells into the lungs, where they rapidly formed highly organized and distinctive Bronchial Associated Lymphoid Tissue (BALT) not induced by any wild type Bordetella species, and a much more rapid and strong antibody response than observed with any of these species. Immunity induced by the mutant was measurably more robust in all respiratory organs, providing completely sterilizing immunity that protected against challenge infections for many months. Moreover, the mutant induced sterilizing immunity against infection with other classical bordetellae, including B. pertussis and B. parapertussis, something the current vaccines do not provide. These findings reveal profound immunomodulation by bordetellae and demonstrate that by disrupting it much more robust protective immunity can be generated, providing a pathway to greatly improve vaccines and preventive treatments against these important pathogens.
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Affiliation(s)
- Monica C Gestal
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America.
| | - Laura K Howard
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
| | - Kalyan Dewan
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
| | - Hannah M Johnson
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
| | - Mariette Barbier
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University, Morgantown, WV, United States of America
- Vaccine Development Center at West Virginia University Health Sciences Center, Morgantown, West Virginia, United States of America
| | - Clare Bryant
- Department of Veterinary Medicine, University of Cambridge, Cambridge, CB3 0ES, United Kingdom
| | - Illiassou Hamidou Soumana
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
| | - Israel Rivera
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
| | - Bodo Linz
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
| | - Uriel Blas-Machado
- Department of Pathology, Athens Veterinary Diagnostic Laboratory, University of Georgia, Athens, Georgia, United States of America
| | - Eric T Harvill
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America.
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20
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Steering Phages to Combat Bacterial Pathogens. Trends Microbiol 2019; 28:85-94. [PMID: 31744662 DOI: 10.1016/j.tim.2019.10.007] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 10/10/2019] [Accepted: 10/17/2019] [Indexed: 12/21/2022]
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21
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O'Brien S, Kümmerli R, Paterson S, Winstanley C, Brockhurst MA. Transposable temperate phages promote the evolution of divergent social strategies in Pseudomonas aeruginosa populations. Proc Biol Sci 2019; 286:20191794. [PMID: 31594506 DOI: 10.1098/rspb.2019.1794] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Transposable temperate phages randomly insert into bacterial genomes, providing increased supply and altered spectra of mutations available to selection, thus opening alternative evolutionary trajectories. Transposable phages accelerate bacterial adaptation to new environments, but their effect on adaptation to the social environment is unclear. Using experimental evolution of Pseudomonas aeruginosa in iron-limited and iron-rich environments, where the cost of producing cooperative iron-chelating siderophores is high and low, respectively, we show that transposable phages promote divergence into extreme siderophore production phenotypes. Iron-limited populations with transposable phages evolved siderophore overproducing clones alongside siderophore non-producing cheats. Low siderophore production was associated with parallel mutations in pvd genes, encoding pyoverdine biosynthesis, and pqs genes, encoding quinolone signalling, while high siderophore production was associated with parallel mutations in phenazine-associated gene clusters. Notably, some of these parallel mutations were caused by phage insertional inactivation. These data suggest that transposable phages, which are widespread in microbial communities, can mediate the evolutionary divergence of social strategies.
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Affiliation(s)
- Siobhán O'Brien
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | - Rolf Kümmerli
- Department of Plant and Microbial Biology, University of Zürich, Switzerland
| | - Steve Paterson
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | - Craig Winstanley
- Institute of Infection and Global Health, University of Liverpool, Liverpool L69 7BE, UK
| | - Michael A Brockhurst
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
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22
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Lewis RW, Islam A, Opdahl L, Davenport JR, Sullivan TS. Comparative Genomics, Siderophore Production, and Iron Scavenging Potential of Root Zone Soil Bacteria Isolated from 'Concord' Grape Vineyards. MICROBIAL ECOLOGY 2019; 78:699-713. [PMID: 30770943 DOI: 10.1007/s00248-019-01324-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 01/10/2019] [Indexed: 06/09/2023]
Abstract
Iron (Fe) deficiency in crop production is a worldwide problem which often results in chlorosis in grapevines, particularly in calcareous soils. Siderophores secreted by microorganisms and Strategy II plants can chelate Fe and other metals in soil solution, and siderophore-Fe complexes can then be utilized by plants and microbes. Plants may also shift rhizosphere conditions to favor siderophore-producing microbes, which can increase plant available Fe. Between-row cover crops (barley, rye, wheat, wheat/vetch) were planted as living mulch to address grapevine chlorosis by enhancing soil health in two vineyards in central Washington. The objectives of the current study were to (1) enrich for siderophore-producing organisms from within the indigenous rooting zone community of 'Concord' grapevines, and (2) perform comparative genomics on putative siderophore producing organisms to assess potentially important Fe acquisition-related functional domains and protein families. A high-throughput, chrome azurol S (CAS)-based enrichment assay was used to select siderophore-producing microbes from 'Concord' grapevine root zone soil. Next-generation whole genome sequencing allowed the assembly and annotation of ten full genomes. Phylogenetic analysis revealed two distinct clades among the genomes using the 40 nearest neighbors available in the public database, all of which were of the Pseudomonas genus. Significant differences in functional domain abundances were observed between the clades including iron acquisition and metabolism of amino acids, carbon, nitrogen, phosphate, and sulfur. Diverse mechanisms of Fe uptake and siderophore production/uptake were identified in the protein families of the genomes. The sequenced organisms are likely pseudomonads which are well-suited for iron scavenging, suggesting a potential role in Fe turnover in vineyard systems.
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Affiliation(s)
- Ricky W Lewis
- Department of Crop and Soil Sciences, Washington State University, PO Box 646420, Pullman, WA, USA
| | - Anjuman Islam
- Department of Crop and Soil Sciences, Washington State University, PO Box 646420, Pullman, WA, USA
| | - Lee Opdahl
- Department of Crop and Soil Sciences, Washington State University, PO Box 646420, Pullman, WA, USA
| | - Joan R Davenport
- Irrigated Agriculture Research and Extension Center, Washington State University, 24106 N. Bunn Road, Prosser, WA, USA
| | - Tarah S Sullivan
- Department of Crop and Soil Sciences, Washington State University, PO Box 646420, Pullman, WA, USA.
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23
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Chemistry and Biology of Siderophores from Marine Microbes. Mar Drugs 2019; 17:md17100562. [PMID: 31569555 PMCID: PMC6836290 DOI: 10.3390/md17100562] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 09/22/2019] [Accepted: 09/29/2019] [Indexed: 12/30/2022] Open
Abstract
Microbial siderophores are multidentate Fe(III) chelators used by microbes during siderophore-mediated assimilation. They possess high affinity and selectivity for Fe(III). Among them, marine siderophore-mediated microbial iron uptake allows marine microbes to proliferate and survive in the iron-deficient marine environments. Due to their unique iron(III)-chelating properties, delivery system, structural diversity, and therapeutic potential, marine microbial siderophores have great potential for further development of various drug conjugates for antibiotic-resistant bacteria therapy or as a target for inhibiting siderophore virulence factors to develop novel broad-spectrum antibiotics. This review covers siderophores derived from marine microbes.
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24
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Wechsler T, Kümmerli R, Dobay A. Understanding policing as a mechanism of cheater control in cooperating bacteria. J Evol Biol 2019; 32:412-424. [PMID: 30724418 PMCID: PMC6520251 DOI: 10.1111/jeb.13423] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 01/30/2019] [Accepted: 01/31/2019] [Indexed: 12/17/2022]
Abstract
Policing occurs in insect, animal and human societies, where it evolved as a mechanism maintaining cooperation. Recently, it has been suggested that policing might even be relevant in enforcing cooperation in much simpler organisms such as bacteria. Here, we used individual-based modelling to develop an evolutionary concept for policing in bacteria and identify the conditions under which it can be adaptive. We modelled interactions between cooperators, producing a beneficial public good, cheaters, exploiting the public good without contributing to it, and public good-producing policers that secrete a toxin to selectively target cheaters. We found that toxin-mediated policing is favoured when (a) toxins are potent and durable, (b) toxins are cheap to produce, (c) cell and public good diffusion is intermediate, and (d) toxins diffuse farther than the public good. Although our simulations identify the parameter space where toxin-mediated policing can evolve, we further found that policing decays when the genetic linkage between public good and toxin production breaks. This is because policing is itself a public good, offering protection to toxin-resistant mutants that still produce public goods, yet no longer invest in toxins. Our work thus highlights that not only specific environmental conditions are required for toxin-mediated policing to evolve, but also strong genetic linkage between the expression of public goods, toxins and toxin resistance is essential for this mechanism to remain evolutionarily stable in the long run.
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Affiliation(s)
- Tobias Wechsler
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Rolf Kümmerli
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Akos Dobay
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
- Zurich Institute of Forensic Medicine, University of Zurich, Zurich, Switzerland
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25
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Gestal MC, Whitesides LT, Harvill ET. Integrated Signaling Pathways Mediate Bordetella Immunomodulation, Persistence, and Transmission. Trends Microbiol 2018; 27:118-130. [PMID: 30661570 DOI: 10.1016/j.tim.2018.09.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 08/17/2018] [Accepted: 09/28/2018] [Indexed: 01/01/2023]
Abstract
The mammalian immune system includes a sophisticated array of antimicrobial mechanisms. However, successful pathogens have developed subversive strategies to detect, modulate, and/or evade immune control and clearance. Independent disciplines study host immunology and bacterial pathogenesis, but interkingdom signaling between bacteria and host during natural infection remains poorly understood. An efficient natural host infection system has revealed complex communication between Bordetella spp. and mice, identified novel regulatory mechanisms, and demonstrated that bordetellae can respond to microenvironment and inflammatory status cues. Understanding these bacterial signaling pathways and their complex network that allows precisely timed expression of numerous immunomodulatory factors will serve as a paradigm for other organisms lacking such a powerful experimental infection system. VIDEO ABSTRACT.
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Affiliation(s)
- M C Gestal
- Deaprtment of Infectious Diseases, College of Veterinary Medicine, University of Georgia. 501 DW Brooks Drive, 30602, Athens, Georgia, USA.
| | - L T Whitesides
- Deaprtment of Infectious Diseases, College of Veterinary Medicine, University of Georgia. 501 DW Brooks Drive, 30602, Athens, Georgia, USA
| | - E T Harvill
- Deaprtment of Infectious Diseases, College of Veterinary Medicine, University of Georgia. 501 DW Brooks Drive, 30602, Athens, Georgia, USA.
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26
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Lin J, Cheng J, Wang Y, Shen X. The Pseudomonas Quinolone Signal (PQS): Not Just for Quorum Sensing Anymore. Front Cell Infect Microbiol 2018; 8:230. [PMID: 30023354 PMCID: PMC6039570 DOI: 10.3389/fcimb.2018.00230] [Citation(s) in RCA: 136] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 06/18/2018] [Indexed: 12/26/2022] Open
Abstract
The Pseudomonas quinolone signal (PQS) has been studied primarily in the context of its role as a quorum-sensing signaling molecule. Recent data suggest, however, that this molecule may also function to mediate iron acquisition, cytotoxicity, outer-membrane vesicle biogenesis, or to exert host immune modulatory activities.
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Affiliation(s)
- Jinshui Lin
- Shaanxi Engineering and Technological Research Center for Conservation and Utilization of Regional Biological Resources, Yan'an University, Yan'an, China.,College of Life Sciences, Yan'an University, Yan'an, China
| | - Juanli Cheng
- Shaanxi Engineering and Technological Research Center for Conservation and Utilization of Regional Biological Resources, Yan'an University, Yan'an, China.,College of Life Sciences, Yan'an University, Yan'an, China
| | - Yao Wang
- Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, China.,State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, China
| | - Xihui Shen
- Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, China.,State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, China
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27
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Shibasaki S, Shimada M. Cyclic dominance emerges from the evolution of two inter-linked cooperative behaviours in the social amoeba. Proc Biol Sci 2018; 285:rspb.2018.0905. [PMID: 29925622 DOI: 10.1098/rspb.2018.0905] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 05/30/2018] [Indexed: 11/12/2022] Open
Abstract
Evolution of cooperation has been one of the most important problems in sociobiology, and many researchers have revealed mechanisms that can facilitate the evolution of cooperation. However, most studies deal only with one cooperative behaviour, even though some organisms perform two or more cooperative behaviours. The social amoeba Dictyostelium discoideum performs two cooperative behaviours in starvation: fruiting body formation and macrocyst formation. Here, we constructed a model that couples these two behaviours, and we found that the two behaviours are maintained because of the emergence of cyclic dominance, although cooperation cannot evolve if only either of the two behaviours is performed. The common chemoattractant cyclic adenosine 3',5'-monophosphate (cAMP) is used in both fruiting body formation and macrocyst formation, providing a biological context for this coupling. Cyclic dominance emerges regardless of the existence of mating types or spatial structure in the model. In addition, cooperation can re-emerge in the population even after it goes extinct. These results indicate that the two cooperative behaviours of the social amoeba are maintained because of the common chemical signal that underlies both fruiting body formation and macrocyst formation. We demonstrate the importance of coupling multiple games when the underlying behaviours are associated with one another.
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Affiliation(s)
- Shota Shibasaki
- Department of General Systems Studies, Graduate School of Arts and Sciences, the University of Tokyo, Tokyo 1538902, Japan
| | - Masakazu Shimada
- Department of General Systems Studies, Graduate School of Arts and Sciences, the University of Tokyo, Tokyo 1538902, Japan
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Popat R, Harrison F, da Silva AC, Easton SAS, McNally L, Williams P, Diggle SP. Environmental modification via a quorum sensing molecule influences the social landscape of siderophore production. Proc Biol Sci 2017; 284:rspb.2017.0200. [PMID: 28404780 PMCID: PMC5394672 DOI: 10.1098/rspb.2017.0200] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 03/16/2017] [Indexed: 12/12/2022] Open
Abstract
Bacteria produce a wide variety of exoproducts that favourably modify their environment and increase their fitness. These are often termed ‘public goods’ because they are costly for individuals to produce and can be exploited by non-producers (cheats). The outcome of conflict over public goods is dependent upon the prevailing environment and the phenotype of the individuals in competition. Many bacterial species use quorum sensing (QS) signalling molecules to regulate the production of public goods. QS, therefore, determines the cooperative phenotype of individuals, and influences conflict over public goods. In addition to their regulatory functions, many QS molecules have additional properties that directly modify the prevailing environment. This leads to the possibility that QS molecules could influence conflict over public goods indirectly through non-signalling effects, and the impact of this on social competition has not previously been explored. The Pseudomonas aeruginosa QS signal molecule PQS is a powerful chelator of iron which can cause an iron starvation response. Here, we show that PQS stimulates a concentration-dependent increase in the cooperative production of iron scavenging siderophores, resulting in an increase in the relative fitness of non-producing siderophore cheats. This is likely due to an increased cost of siderophore output by producing cells and a concurrent increase in the shared benefits, which accrue to both producers and cheats. Although PQS can be a beneficial signalling molecule for P. aeruginosa, our data suggest that it can also render a siderophore-producing population vulnerable to competition from cheating strains. More generally, our results indicate that the production of one social trait can indirectly affect the costs and benefits of another social trait.
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Affiliation(s)
- Roman Popat
- School of Life Sciences, Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Freya Harrison
- School of Life Sciences, Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK.,School of Life Sciences, University of Warwick, Gibbet Hill Campus, Coventry CV4 7AL, UK
| | - Ana C da Silva
- School of Life Sciences, Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Scott A S Easton
- School of Life Sciences, Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Luke McNally
- Centre for Immunity, Infection and Evolution, Ashworth Laboratories, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Paul Williams
- School of Life Sciences, Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Stephen P Diggle
- School of Life Sciences, Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK
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Maintenance of Microbial Cooperation Mediated by Public Goods in Single- and Multiple-Trait Scenarios. J Bacteriol 2017; 199:JB.00297-17. [PMID: 28847922 DOI: 10.1128/jb.00297-17] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Microbes often form densely populated communities, which favor competitive and cooperative interactions. Cooperation among bacteria often occurs through the production of metabolically costly molecules produced by certain individuals that become available to other neighboring individuals; such molecules are called public goods. This type of cooperation is susceptible to exploitation, since nonproducers of a public good can benefit from it while saving the cost of its production (cheating), gaining a fitness advantage over producers (cooperators). Thus, in mixed cultures, cheaters can increase in frequency in the population, relative to cooperators. Sometimes, and as predicted by simple game-theoretic arguments, such increases in the frequency of cheaters cause loss of the cooperative traits by exhaustion of the public goods, eventually leading to a collapse of the entire population. In other cases, however, both cooperators and cheaters remain in coexistence. This raises the question of how cooperation is maintained in microbial populations. Several strategies to prevent cheating have been studied in the context of a single trait and a unique environmental constraint. In this review, we describe current knowledge on the evolutionary stability of microbial cooperation and discuss recent discoveries describing the mechanisms operating in multiple-trait and multiple-constraint settings. We conclude with a consideration of the consequences of these complex interactions, and we briefly discuss the potential role of social interactions involving multiple traits and multiple environmental constraints in the evolution of specialization and division of labor in microbes.
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