1
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Di Chiara M, Lazzaro A, Scribano D, Trancassini M, Pietropaolo V, Sonnessa M, De Luca C, Prota R, Onestà E, Laccetta G, Terrin G. Reduced Gut Bacterial Diversity in Early Life Predicts Feeding Intolerance in Preterm Neonates. Trop Med Infect Dis 2024; 9:174. [PMID: 39195612 PMCID: PMC11359060 DOI: 10.3390/tropicalmed9080174] [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: 05/30/2024] [Revised: 07/10/2024] [Accepted: 07/12/2024] [Indexed: 08/29/2024] Open
Abstract
Microbiota plays a crucial role in intestinal maturation in preterm newborns. The clinical manifestation of the immaturity of the gastro-intestinal tract is called feeding intolerance (FI). This condition may resolve spontaneously or dramatically evolve into necrotizing enterocolitis. One of the most challenging tasks for the neonatologist is to identify those neonates that will develop the disease early in order to adequately provide nutrition to these patients, from the very first hours of life. A close interplay between the maturity of the gastro-intestinal tract and gut microbiota has been described; however, in preterm neonates, this relationship is still undefined. We analyzed the bacterial composition of stool samples, collected early in life, from 30 preterm newborns classified as intolerant or tolerant according to the degree of readiness of the gastro-intestinal tract to receive enteral nutrition. The Pielou evenness index was significantly increased in intolerant compared with tolerant newborns. Data corrected for confounding variables confirmed that the occurrence of gut maturation was independently influenced by Pielou evenness at birth. A lower bacterial diversity very early in life is associated with improved feeding tolerance in preterm newborns. The abundance analysis showed that neonates not ready to receive enteral nutrition for feeding intolerance show, after birth, an increased abundance of Proteobacteria, Lachnospiracae, Enterobacter and Acinetobacter. We can argue that those are the taxa that prevent the establishment of pioneer bacteria. A lower alpha-diversity, in the first days of life, may facilitate the seeding of beneficial pioneer bacteria that, in turn, drive healthy microbial colonization during neonatal life.
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Affiliation(s)
- Maria Di Chiara
- Department of Maternal Infantile and Urological Sciences, Sapienza University of Rome, Viale del Policlinico 155, 00161 Rome, Italy (G.L.)
| | - Alessandro Lazzaro
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Viale del Policlinico 155, 00161 Rome, Italy; (A.L.); (D.S.); (M.T.)
| | - Daniela Scribano
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Viale del Policlinico 155, 00161 Rome, Italy; (A.L.); (D.S.); (M.T.)
| | - Maria Trancassini
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Viale del Policlinico 155, 00161 Rome, Italy; (A.L.); (D.S.); (M.T.)
| | - Valeria Pietropaolo
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Viale del Policlinico 155, 00161 Rome, Italy; (A.L.); (D.S.); (M.T.)
| | | | - Chiara De Luca
- Department of Maternal Infantile and Urological Sciences, Sapienza University of Rome, Viale del Policlinico 155, 00161 Rome, Italy (G.L.)
| | - Rita Prota
- Department of Maternal Infantile and Urological Sciences, Sapienza University of Rome, Viale del Policlinico 155, 00161 Rome, Italy (G.L.)
| | - Elisa Onestà
- Department of Maternal Infantile and Urological Sciences, Sapienza University of Rome, Viale del Policlinico 155, 00161 Rome, Italy (G.L.)
| | - Gianluigi Laccetta
- Department of Maternal Infantile and Urological Sciences, Sapienza University of Rome, Viale del Policlinico 155, 00161 Rome, Italy (G.L.)
| | - Gianluca Terrin
- Department of Maternal Infantile and Urological Sciences, Sapienza University of Rome, Viale del Policlinico 155, 00161 Rome, Italy (G.L.)
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2
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Sandhu AK, Fischer BR, Subramanian S, Hoppe AD, Brözel VS. Self-growth suppression in Bradyrhizobium diazoefficiens is caused by a diffusible antagonist. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.01.596975. [PMID: 38853965 PMCID: PMC11160724 DOI: 10.1101/2024.06.01.596975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
Microbes in soil navigate interactions by recognizing kin, forming social groups, exhibiting antagonistic behavior, and engaging in competitive kin rivalry. Here, we investigated a novel phenomenon of self-growth suppression (sibling rivalry) observed in Bradyrhizobium diazoefficiens USDA 110. Swimming colonies of USDA 110 developed a distinct demarcation line and inter-colony zone when inoculated adjacent to each other. In addition to self, USDA 110 suppressed growth of other Bradyrhizobium strains and several other soil bacteria. We demonstrated that the phenomenon of sibling rivalry is due to growth suppression but not cell death. The cells in the inter-colony zone were culturable but have reduced respiratory activity, ATP levels and motility. The observed growth suppression was due to the presence of a diffusible effector compound. This effector was labile, preventing extraction, and identification, but it is unlikely a protein or a strong acid or base. This counterintuitive phenomenon of self-growth suppression suggests a strategic adaptation for conserving energy and resources in competitive soil environments. Bradyrhizobium's utilization of antagonism including self-growth suppression likely provides a competitive advantage for long-term success in soil ecosystems.
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Affiliation(s)
- Armaan Kaur Sandhu
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57006
| | - Brady R. Fischer
- Department of Chemistry, Biochemistry and Physics, South Dakota State University, Brookings, SD 57006
| | - Senthil Subramanian
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57006
| | - Adam D. Hoppe
- Department of Chemistry, Biochemistry and Physics, South Dakota State University, Brookings, SD 57006
| | - Volker S. Brözel
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57006
- Department of Biochemistry, Genetics and Microbiology; Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
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3
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Kastrat E, Cheng HP. Escherichia coli has an undiscovered ability to inhibit the growth of both Gram-negative and Gram-positive bacteria. Sci Rep 2024; 14:7420. [PMID: 38548840 PMCID: PMC10978900 DOI: 10.1038/s41598-024-57996-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 03/25/2024] [Indexed: 04/01/2024] Open
Abstract
The ability for bacteria to form boundaries between neighboring colonies as the result of intra-species inhibition has been described for a limited number of species. Here, we report that intra-species inhibition is more common than previously recognized. We demonstrated that swimming colonies of four Escherichia coli strains and six other bacteria form inhibitory zones between colonies, which is not caused by nutrient depletion. This phenomenon was similarly observed with non-flagellated bacteria. We developed a square-streaking pattern assay which revealed that Escherichia coli BW25113 inhibits the growth of other E. coli, and surprisingly, other Gram-positive and negative bacteria, including multi-drug resistant clinical isolates. Altogether, our findings demonstrate intra-species inhibition is common and might be used by E. coli to inhibit other bacteria. Our findings raise the possibility for a common mechanism shared across bacteria for intra-species inhibition. This can be further explored for a potential new class of antibiotics.
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Affiliation(s)
- Ertan Kastrat
- Department of Biological Sciences, Lehman College, City University of New York, Bronx, NY, 10468, USA
- The Graduate Center, City University of New York, New York, NY, 10016, USA
| | - Hai-Ping Cheng
- Department of Biological Sciences, Lehman College, City University of New York, Bronx, NY, 10468, USA.
- The Graduate Center, City University of New York, New York, NY, 10016, USA.
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4
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Abstract
Bacteria commonly live in surface-associated communities where steep gradients of antibiotics and other chemical compounds can occur. While many bacterial species move on surfaces, we know surprisingly little about how such antibiotic gradients affect cell motility. Here, we study the behaviour of the opportunistic pathogen Pseudomonas aeruginosa in stable spatial gradients of several antibiotics by tracking thousands of cells in microfluidic devices as they form biofilms. Unexpectedly, these experiments reveal that bacteria use pili-based ('twitching') motility to navigate towards antibiotics. Our analyses suggest that this behaviour is driven by a general response to the effects of antibiotics on cells. Migrating bacteria reach antibiotic concentrations hundreds of times higher than their minimum inhibitory concentration within hours and remain highly motile. However, isolating cells - using fluid-walled microfluidic devices - reveals that these bacteria are terminal and unable to reproduce. Despite moving towards their death, migrating cells are capable of entering a suicidal program to release bacteriocins that kill other bacteria. This behaviour suggests that the cells are responding to antibiotics as if they come from a competing colony growing nearby, inducing them to invade and attack. As a result, clinical antibiotics have the potential to lure bacteria to their death.
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5
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Eigentler L, Davidson FA, Stanley-Wall NR. Mechanisms driving spatial distribution of residents in colony biofilms: an interdisciplinary perspective. Open Biol 2022; 12:220194. [PMID: 36514980 PMCID: PMC9748781 DOI: 10.1098/rsob.220194] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Biofilms are consortia of microorganisms that form collectives through the excretion of extracellular matrix compounds. The importance of biofilms in biological, industrial and medical settings has long been recognized due to their emergent properties and impact on surrounding environments. In laboratory situations, one commonly used approach to study biofilm formation mechanisms is the colony biofilm assay, in which cell communities grow on solid-gas interfaces on agar plates after the deposition of a population of founder cells. The residents of a colony biofilm can self-organize to form intricate spatial distributions. The assay is ideally suited to coupling with mathematical modelling due to the ability to extract a wide range of metrics. In this review, we highlight how interdisciplinary approaches have provided deep insights into mechanisms causing the emergence of these spatial distributions from well-mixed inocula.
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Affiliation(s)
- Lukas Eigentler
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK,Mathematics, School of Science and Engineering, University of Dundee, Dundee DD1 4HN, UK
| | - Fordyce A. Davidson
- Mathematics, School of Science and Engineering, University of Dundee, Dundee DD1 4HN, UK
| | - Nicola R. Stanley-Wall
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
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6
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Niehus R, Oliveira NM, Li A, Fletcher AG, Foster KR. The evolution of strategy in bacterial warfare via the regulation of bacteriocins and antibiotics. eLife 2021; 10:69756. [PMID: 34488940 PMCID: PMC8423443 DOI: 10.7554/elife.69756] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Accepted: 08/01/2021] [Indexed: 12/21/2022] Open
Abstract
Bacteria inhibit and kill one another with a diverse array of compounds, including bacteriocins and antibiotics. These attacks are highly regulated, but we lack a clear understanding of the evolutionary logic underlying this regulation. Here, we combine a detailed dynamic model of bacterial competition with evolutionary game theory to study the rules of bacterial warfare. We model a large range of possible combat strategies based upon the molecular biology of bacterial regulatory networks. Our model predicts that regulated strategies, which use quorum sensing or stress responses to regulate toxin production, will readily evolve as they outcompete constitutive toxin production. Amongst regulated strategies, we show that a particularly successful strategy is to upregulate toxin production in response to an incoming competitor’s toxin, which can be achieved via stress responses that detect cell damage (competition sensing). Mirroring classical game theory, our work suggests a fundamental advantage to reciprocation. However, in contrast to classical results, we argue that reciprocation in bacteria serves not to promote peaceful outcomes but to enable efficient and effective attacks.
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Affiliation(s)
- Rene Niehus
- Center for Communicable Disease Dynamics, Harvard TH Chan School of Public Health, Harvard University, Boston, United States
| | - Nuno M Oliveira
- Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge, United Kingdom.,Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Aming Li
- Center for Systems and Control, College of Engineering, Peking University, Beijing, China.,Institue for Artificial Intelligence, Peking University, Beijing, China
| | - Alexander G Fletcher
- School of Mathematics and Statistics, University of Sheffield, Sheffield, United Kingdom.,The Bateson Centre, University of Sheffield, Sheffield, United Kingdom
| | - Kevin R Foster
- Department of Zoology, University of Oxford, Oxford, United Kingdom.,Department of Biochemistry, University of Oxford, Oxford, United Kingdom
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7
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Wang X, Zhang D, Dong F, Liu S, Zhang J, Zhao H. Cell differentiation and motion determine the Bacillus subtilis biofilm morphological evolution under the competitive growth. J Basic Microbiol 2021; 61:396-405. [PMID: 33682160 DOI: 10.1002/jobm.202000635] [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: 10/24/2020] [Revised: 12/23/2020] [Accepted: 01/12/2021] [Indexed: 11/06/2022]
Abstract
The growth discrepancy of Bacillus subtilis biofilms along different directions under the competitive growth drive the formation of anisotropic biofilm morphology directly. Two biofilms growing from two inoculating positions with different distances exhibit promoting or inhibiting growth behavior. Here we develop an optical imaging technology to observe the cell differentiation and the growth dynamics when the biofilm grows. It shows that the spatiotemporal distribution of different phenotypes affects the biofilm morphological evolution. We develop a program to calculate the velocity of cell motion within the biofilm, which is based on the feature point matching approach. We find the cell differentiation ununiformity in the neighboring region and its opposite region leads to the cell velocity difference in the competitive environment, the different cell motion further influences the biofilm morphology evolution. When biofilms grow with a long inoculating distance, there is always a gap between the them; when biofilms grow with a short inoculating distance, two biofilms gradually merge into a whole. Our work establishes a relationship between microscopic cells and macroscopic biofilm morphological which enables us to study the competitive growth process of biofilms from multiple perspectives.
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Affiliation(s)
- Xiaoling Wang
- School of Mechanical Engineering, University of Science and Technology Beijing, Beijing, China.,School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Duohuai Zhang
- School of Mechanical Engineering, University of Science and Technology Beijing, Beijing, China
| | - Fulin Dong
- School of Mechanical Engineering, University of Science and Technology Beijing, Beijing, China
| | - Song Liu
- School of Mechanical Engineering, University of Science and Technology Beijing, Beijing, China
| | - Jinchang Zhang
- School of Mechanical Engineering, University of Science and Technology Beijing, Beijing, China
| | - Hui Zhao
- University of Chinese Academy of Sciences, State Key Laboratory of Computer Science, Institute of Software, China
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8
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Loss of Motility as a Non-Lethal Mechanism for Intercolony Inhibition ("Sibling Rivalry") in Marinobacter. Microorganisms 2021; 9:microorganisms9010103. [PMID: 33466273 PMCID: PMC7824750 DOI: 10.3390/microorganisms9010103] [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: 11/19/2020] [Revised: 12/23/2020] [Accepted: 12/30/2020] [Indexed: 11/17/2022] Open
Abstract
Bacteria from the genus Marinobacter are ubiquitous throughout the worlds' oceans as "opportunitrophs" capable of surviving a wide range of conditions, including colonization of surfaces of marine snow and algae. To prevent too many bacteria from occupying this ecological niche simultaneously, some sort of population dependent control must be operative. Here, we show that while Marinobacter do not produce or utilize an acylhomoserine lactone (AHL)-based quorum sensing system, "sibling" colonies of many species of Marinobacter exhibit a form of non-lethal chemical communication that prevents colonies from overrunning each other's niche space. Evidence suggests that this inhibition is the result of a loss in motility for cells at the colony interfaces. Although not the signal itself, we have identified a protein, glycerophosphoryl diester phosphodiesterase, that is enriched in the inhibition zone between the spreading colonies that may be part of the overall response.
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9
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Kantsler V, Ontañón-McDonald E, Kuey C, Ghanshyam MJ, Roffin MC, Asally M. Pattern Engineering of Living Bacterial Colonies Using Meniscus-Driven Fluidic Channels. ACS Synth Biol 2020; 9:1277-1283. [PMID: 32491836 DOI: 10.1021/acssynbio.0c00146] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Creating adaptive, sustainable, and dynamic biomaterials is a forthcoming mission of synthetic biology. Engineering spatially organized bacterial communities has a potential to develop such bio-metamaterials. However, generating living patterns with precision, robustness, and a low technical barrier remains as a challenge. Here we present an easily implementable technique for patterning live bacterial populations using a controlled meniscus-driven fluidics system, named as MeniFluidics. We demonstrate multiscale patterning of biofilm colonies and swarms with submillimeter resolution. Utilizing the faster bacterial spreading in liquid channels, MeniFluidics allows controlled bacterial colonies both in space and time to organize fluorescently labeled Bacillus subtilis strains into a converged pattern and to form dynamic vortex patterns in confined bacterial swarms. The robustness, accuracy, and low technical barrier of MeniFluidics offer a tool for advancing and inventing new living materials that can be combined with genetically engineered systems, and adding to fundamental research into ecological, evolutional, and physical interactions between microbes.
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Affiliation(s)
- Vasily Kantsler
- Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
- Warwick Medical School, University of Warwick, Coventry CV4 7AL, United Kingdom
| | | | - Cansu Kuey
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Manjari J. Ghanshyam
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Maria Chiara Roffin
- Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Munehiro Asally
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom
- Warwick Integrative Synthetic Biology Centre, University of Warwick, Coventry CV4 7AL, United Kingdom
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10
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Paul R, Ghosh T, Tang T, Kumar A. Reply to the comment on "Rivalry in Bacillus subtilis colonies: enemy or family?". SOFT MATTER 2020; 16:3347-3349. [PMID: 32207512 DOI: 10.1039/d0sm00034e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Sibling Bacillus subtilis colony merging phenomenon at the microscopic length scale has revealed interesting dynamics which depends on the strain and the composition of the growth medium.
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Affiliation(s)
- Rajorshi Paul
- Department of Mechanical Engineering, Stanford University, Stanford, USA
| | - Tanushree Ghosh
- Department of Mechanical Engineering, University of Alberta, Edmonton, Canada
| | - Tian Tang
- Department of Mechanical Engineering, University of Alberta, Edmonton, Canada
| | - Aloke Kumar
- Department of Mechanical Engineering, Indian Institute of Science, Bangalore, India.
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11
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Matoz-Fernandez D, Arnaouteli S, Porter M, MacPhee CE, Stanley-Wall NR, Davidson FA. Comment on "Rivalry in Bacillus subtilis colonies: enemy or family?". SOFT MATTER 2020; 16:3344-3346. [PMID: 32207471 PMCID: PMC8522905 DOI: 10.1039/c9sm02141h] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 01/24/2020] [Indexed: 06/10/2023]
Abstract
It is well known that biofilms are one of the most widespread forms of life on Earth, capable of colonising almost any environment from humans to metals.
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Affiliation(s)
- Daniel Matoz-Fernandez
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK. and Division of Mathematics, School of Science and Engineering, University of Dundee, Dundee DD1 4HN, UK.
| | - Sofia Arnaouteli
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK.
| | - Michael Porter
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK.
| | | | - Nicola R Stanley-Wall
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK.
| | - Fordyce A Davidson
- Division of Mathematics, School of Science and Engineering, University of Dundee, Dundee DD1 4HN, UK.
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12
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Harnessing the Potential of Killers and Altruists within the Microbial Community: A Possible Alternative to Antibiotic Therapy? Antibiotics (Basel) 2019; 8:antibiotics8040230. [PMID: 31766366 PMCID: PMC6963621 DOI: 10.3390/antibiotics8040230] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 11/17/2019] [Accepted: 11/19/2019] [Indexed: 12/29/2022] Open
Abstract
In the context of a post-antibiotic era, the phenomenon of microbial allolysis, which is defined as the partial killing of bacterial population induced by other cells of the same species, may take on greater significance. This phenomenon was revealed in some bacterial species such as Streptococcus pneumoniae and Bacillus subtilis, and has been suspected to occur in some other species or genera, such as enterococci. The mechanisms of this phenomenon, as well as its role in the life of microbial populations still form part of ongoing research. Herein, we describe recent developments in allolysis in the context of its practical benefits as a form of cell death that may give rise to developing new strategies for manipulating the life and death of bacterial communities. We highlight how such findings may be viewed with importance and potential within the fields of medicine, biotechnology, and pharmacology.
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13
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Paul R, Ghosh T, Tang T, Kumar A. Rivalry in Bacillus subtilis colonies: enemy or family? SOFT MATTER 2019; 15:5400-5411. [PMID: 31172158 DOI: 10.1039/c9sm00794f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Two colonies of Bacillus subtilis of identical strains growing adjacent to each other on an agar plate exhibit two distinct types of interactions: they either merge as they grow or demarcation occurs leading to formation of a line of demarcation at the colony fronts. The nature of this interaction depends on the agar concentration in the growth medium and the initial separation between the colonies. When the agar concentration was 0.67% or lower, the two sibling colonies were found to always merge. At 1% or higher concentrations, the colonies formed a demarcation line only when their initial separation was 20 mm or higher. Interactions of a colony with solid structures and liquid drops have indicated that biochemical factors rather than the presence of physical obstacles are responsible for the demarcation line formation. A reaction diffusion model has been formulated to predict if two sibling colonies will form a demarcation line under given agar concentration and initial separation. The model prediction agrees well with experimental findings and generates a dimensionless phase diagram containing merging and demarcation regimes. The phase diagram is in terms of a dimensionless initial separation, d[combining macron], and a dimensionless diffusion coefficient, D[combining macron], of the colonies. The phase boundary between the two interaction regimes can be described by a power law relation between d[combining macron] and D[combining macron].
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Affiliation(s)
- Rajorshi Paul
- Department of Mechanical Engineering, University of Alberta, Edmonton, Canada
| | - Tanushree Ghosh
- Department of Mechanical Engineering, University of Alberta, Edmonton, Canada
| | - Tian Tang
- Department of Mechanical Engineering, University of Alberta, Edmonton, Canada
| | - Aloke Kumar
- Department of Mechanical Engineering, Indian Institute of Science, Bangalore, India.
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14
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Millet LJ, Aufrecht J, Labbé J, Uehling J, Vilgalys R, Estes ML, Miquel Guennoc C, Deveau A, Olsson S, Bonito G, Doktycz MJ, Retterer ST. Increasing access to microfluidics for studying fungi and other branched biological structures. Fungal Biol Biotechnol 2019; 6:1. [PMID: 31198578 PMCID: PMC6556955 DOI: 10.1186/s40694-019-0071-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 05/15/2019] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Microfluidic systems are well-suited for studying mixed biological communities for improving industrial processes of fermentation, biofuel production, and pharmaceutical production. The results of which have the potential to resolve the underlying mechanisms of growth and transport in these complex branched living systems. Microfluidics provide controlled environments and improved optical access for real-time and high-resolution imaging studies that allow high-content and quantitative analyses. Studying growing branched structures and the dynamics of cellular interactions with both biotic and abiotic cues provides context for molecule production and genetic manipulations. To make progress in this arena, technical and logistical barriers must be overcome to more effectively deploy microfluidics in biological disciplines. A principle technical barrier is the process of assembling, sterilizing, and hydrating the microfluidic system; the lack of the necessary equipment for the preparatory process is a contributing factor to this barrier. To improve access to microfluidic systems, we present the development, characterization, and implementation of a microfluidics assembly and packaging process that builds on self-priming point-of-care principles to achieve "ready-to-use microfluidics." RESULTS We present results from domestic and international collaborations using novel microfluidic architectures prepared with a unique packaging protocol. We implement this approach by focusing primarily on filamentous fungi; we also demonstrate the utility of this approach for collaborations on plants and neurons. In this work we (1) determine the shelf-life of ready-to-use microfluidics, (2) demonstrate biofilm-like colonization on fungi, (3) describe bacterial motility on fungal hyphae (fungal highway), (4) report material-dependent bacterial-fungal colonization, (5) demonstrate germination of vacuum-sealed Arabidopsis seeds in microfluidics stored for up to 2 weeks, and (6) observe bidirectional cytoplasmic streaming in fungi. CONCLUSIONS This pre-packaging approach provides a simple, one step process to initiate microfluidics in any setting for fungal studies, bacteria-fungal interactions, and other biological inquiries. This process improves access to microfluidics for controlling biological microenvironments, and further enabling visual and quantitative analysis of fungal cultures.
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Affiliation(s)
- Larry J. Millet
- Biosciences Division, Oak Ridge National Laboratory, PO Box 2008, MS 6445, Oak Ridge, TN 37831 USA
- The Bredesen Center, University of Tennessee-Knoxville, Knoxville, TN 37996 USA
| | - Jayde Aufrecht
- The Bredesen Center, University of Tennessee-Knoxville, Knoxville, TN 37996 USA
- The Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, PO Box 2008, MS 6445, Oak Ridge, TN 37831 USA
| | - Jessy Labbé
- Biosciences Division, Oak Ridge National Laboratory, PO Box 2008, MS 6445, Oak Ridge, TN 37831 USA
- Department of Biochemistry and Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN 37996 USA
| | - Jessie Uehling
- Biology Department, Duke University, Box 90338, Durham, NC 27708 USA
- Department of Plant and Microbial Biology, University of California at Berkeley, Berkeley, CA 94703 USA
| | - Rytas Vilgalys
- Biology Department, Duke University, Box 90338, Durham, NC 27708 USA
| | - Myka L. Estes
- The Center for Neuroscience, University of California Davis, One Shields Avenue, Davis, CA 95618 USA
| | - Cora Miquel Guennoc
- Biosciences Division, Oak Ridge National Laboratory, PO Box 2008, MS 6445, Oak Ridge, TN 37831 USA
- Institut national de la recherche agronomique (INRA), Centre INRA-Lorraine, 54280 Champenoux, France
| | - Aurélie Deveau
- Institut national de la recherche agronomique (INRA), Centre INRA-Lorraine, 54280 Champenoux, France
| | - Stefan Olsson
- Fujian Agricultural and Forestry University, Fuzhou City, 350002 Fujian Province China
| | - Gregory Bonito
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI 48824 USA
| | - Mitchel J. Doktycz
- Biosciences Division, Oak Ridge National Laboratory, PO Box 2008, MS 6445, Oak Ridge, TN 37831 USA
- The Bredesen Center, University of Tennessee-Knoxville, Knoxville, TN 37996 USA
| | - Scott T. Retterer
- Biosciences Division, Oak Ridge National Laboratory, PO Box 2008, MS 6445, Oak Ridge, TN 37831 USA
- The Bredesen Center, University of Tennessee-Knoxville, Knoxville, TN 37996 USA
- The Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, PO Box 2008, MS 6445, Oak Ridge, TN 37831 USA
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15
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Luzzatto-Knaan T, Melnik AV, Dorrestein PC. Mass Spectrometry Uncovers the Role of Surfactin as an Interspecies Recruitment Factor. ACS Chem Biol 2019; 14:459-467. [PMID: 30763059 DOI: 10.1021/acschembio.8b01120] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Microbes use metabolic exchange to sense and respond to their changing environment. Surfactins, produced by Bacillus subtilis, have been extensively studied for their role in biofilm formation, biosurfactant properties, and antimicrobial activity, affecting the surrounding microbial consortia. Using mass spectrometry, we reveal that Paenibacillus dendritiformis, originally isolated with B. subtilis, is not antagonized by the presence of surfactins and is actually attracted to them. We demonstrate here for the first time that P. dendritiformis is also actively degrading surfactins produced by B. subtilis and accumulating the degradation products that serve as territorial markers. This new attribute as an attractant of selected microbes and the conversion into a deterrent highlight the diverse role natural products have in shaping the environment and establishing mixed communities.
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Affiliation(s)
- Tal Luzzatto-Knaan
- Collaborative Mass Spectrometry Innovation Center, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093, United States
| | - Alexey V. Melnik
- Collaborative Mass Spectrometry Innovation Center, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093, United States
| | - Pieter C. Dorrestein
- Collaborative Mass Spectrometry Innovation Center, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093, United States
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16
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Patra P, Vassallo CN, Wall D, Igoshin OA. Mechanism of Kin-Discriminatory Demarcation Line Formation between Colonies of Swarming Bacteria. Biophys J 2018; 113:2477-2486. [PMID: 29212001 DOI: 10.1016/j.bpj.2017.09.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 09/09/2017] [Accepted: 09/21/2017] [Indexed: 10/18/2022] Open
Abstract
Swarming bacteria use kin discrimination to preferentially associate with their clonemates for certain cooperative behaviors. Kin discrimination can manifest as an apparent demarcation line (a region lacking cells or with much lower cell density) between antagonist strains swarming toward each other. In contrast, two identical strains merge with no demarcation. Experimental studies suggest contact-dependent killing between different strains as a mechanism of kin discrimination, but it is not clear whether this killing is sufficient to explain the observed patterns. Here, we investigate the formation of demarcation line with a mathematical model. First, using data from competition experiments between kin discriminating strains of Myxococcus xanthus and Proteus mirabilis, we found the rates of killing between the strains to be highly asymmetric, i.e., one strain kills another at a much higher rate. Then, to investigate how such asymmetric interactions can lead to a stable demarcation line, we construct reaction-diffusion models for colony expansion of kin-discriminatory strains. Our results demonstrate that a stable demarcation line can form when both cell movement and cell growth cease at low nutrient levels. Further, our study suggests that, depending on the initial separation between the inoculated colonies, the demarcation line may move transiently before stabilizing. We validated these model predictions by observing dynamics of merger between two M. xanthus strains, where one strain expresses a toxin protein that kills a second strain lacking the corresponding antitoxin. Our study therefore provides a theoretical understanding of demarcation line formation between kin-discriminatory populations, and can be used for analyzing and designing future experiments.
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Affiliation(s)
- Pintu Patra
- Center for Theoretical Biological Physics and Department of Bioengineering, Rice University, Houston, Texas
| | | | - Daniel Wall
- Department of Molecular Biology, University of Wyoming, Laramie, Wyoming
| | - Oleg A Igoshin
- Center for Theoretical Biological Physics and Department of Bioengineering, Rice University, Houston, Texas.
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17
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Book G, Ingham C, Ariel G. Modeling cooperating micro-organisms in antibiotic environment. PLoS One 2017; 12:e0190037. [PMID: 29284016 PMCID: PMC5746235 DOI: 10.1371/journal.pone.0190037] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 11/15/2017] [Indexed: 12/19/2022] Open
Abstract
Recent experiments with the bacteria Paenibacillus vortex reveal a remarkable strategy enabling it to cope with antibiotics by cooperating with a different bacterium—Escherichia coli. While P. vortex is a highly effective swarmer, it is sensitive to the antibiotic ampicillin. On the other hand, E. coli can degrade ampicillin but is non-motile when grown on high agar percentages. The two bacterial species form a shared colony in which E. coli is transported by P. vortex and E. coli detoxifies the ampicillin. The paper presents a simplified model, consisting of coupled reaction-diffusion equations, describing the development of ring patterns in the shared colony. Our results demonstrate some of the possible cooperative movement strategies bacteria utilize in order to survive harsh conditions. In addition, we explore the behavior of mixed colonies under new conditions such as antibiotic gradients, synchronization between colonies and possible dynamics of a 3-species system including P. vortex, E. coli and a carbon producing algae that provides nutrients under illuminated, nutrient poor conditions. The derived model was able to simulate an asymmetric relationship between two or three micro-organisms where cooperation is required for survival. Computationally, in order to avoid numerical artifacts due to symmetries within the discretizing grid, the model was solved using a second order Vectorizable Random Lattices method, which is developed as a finite volume scheme on a random grid.
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Affiliation(s)
- Gilad Book
- Department of Mathematics, Bar-Ilan University, Ramat Gan, Israel
| | | | - Gil Ariel
- Department of Mathematics, Bar-Ilan University, Ramat Gan, Israel
- * E-mail:
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18
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McCalla SG, von Brecht JH. Fronts under arrest: Nonlocal boundary dynamics in biology. Phys Rev E 2016; 94:060401. [PMID: 28085406 DOI: 10.1103/physreve.94.060401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Indexed: 06/06/2023]
Abstract
We introduce a minimal geometric partial differential equation framework to understand pattern formation from interacting, counterpropagating fronts. Our approach concentrates on the interfaces between different states in a system, and relies on both nonlocal interactions and mean-curvature flow to track their evolution. As an illustration, we use this approach to describe a phenomenon in bacterial colony formation wherein sibling colonies can arrest each other's growth. This arrested motion leads to static separations between healthy, growing colonies. As our minimal model faithfully recovers the geometry of these competing colonies, it captures and elucidates the key leading-order mechanisms responsible for such patterned growth.
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Affiliation(s)
- Scott G McCalla
- Department of Mathematical Sciences, MSU, Bozeman, Montana 59717, USA and Department of Mathematics and Statistics, CSULB, Long Beach, California 90840, USA
| | - James H von Brecht
- Department of Mathematical Sciences, MSU, Bozeman, Montana 59717, USA and Department of Mathematics and Statistics, CSULB, Long Beach, California 90840, USA
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19
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Chakraborty B, Mallick A, Annagiri S, Sengupta S, Sengupta TK. Deciphering a survival strategy during the interspecific competition between Bacillus cereus MSM-S1 and Pseudomonas sp. MSM-M1. ROYAL SOCIETY OPEN SCIENCE 2016; 3:160438. [PMID: 28018625 PMCID: PMC5180123 DOI: 10.1098/rsos.160438] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 10/19/2016] [Indexed: 06/06/2023]
Abstract
Interspecific competition in bacteria governs colony growth dynamics and pattern formation. Here, we demonstrate an interesting phenomenon of interspecific competition between Bacillus cereus MSM-S1 and Pseudomonas sp. MSM-M1, where secretion of an inhibitor by Pseudomonas sp. is used as a strategy for survival. Although B. cereus grows faster than Pseudomonas sp., in the presence of Pseudomonas sp. the population of B. cereus reduces significantly, whereas Pseudomonas sp. do not show any marked alteration in their population growth. Appearance of a zone of inhibition between growing colonies of two species on nutrient agar prevents the expanding front of the MSM-S1 colony from accessing and depleting nutrients in the region occupied by MSM-M1, thereby aiding the survival of the slower growing MSM-M1 colonies. To support our experimental results, we present simulations, based on a chemotactic model of colony growth dynamics. We demonstrate that the chemical(s) secreted by Pseudomonas sp. is responsible for the observed inhibition of growth and spatial pattern of the B. cereus MSM-S1 colony. Our experimental results are in excellent agreement with the numerical results and confirm that secreted inhibitors enable Pseudomonas sp. to survive and coexist in the presence of faster growing B. cereus, in a common niche.
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Affiliation(s)
- Brinta Chakraborty
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur 741246, India
| | - Anish Mallick
- Department of Mathematical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur 741246, India
| | - Sumana Annagiri
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur 741246, India
| | - Supratim Sengupta
- Department of Physical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur 741246, India
| | - Tapas K. Sengupta
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur 741246, India
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Abstract
The ability of bacteria to recognize kin provides a means to form social groups. In turn these groups can lead to cooperative behaviors that surpass the ability of the individual. Kin recognition involves specific biochemical interactions between a receptor(s) and an identification molecule(s). Recognition specificity, ensuring that nonkin are excluded and kin are included, is critical and depends on the number of loci and polymorphisms involved. After recognition and biochemical perception, the common ensuing cooperative behaviors include biofilm formation, quorum responses, development, and swarming motility. Although kin recognition is a fundamental mechanism through which cells might interact, microbiologists are only beginning to explore the topic. This review considers both molecular and theoretical aspects of bacterial kin recognition. Consideration is also given to bacterial diversity, genetic relatedness, kin selection theory, and mechanisms of recognition.
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Affiliation(s)
- Daniel Wall
- Department of Molecular Biology, University of Wyoming, Laramie, Wyoming 82071;
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21
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Taylor JD, Taylor G, Hare SA, Matthews SJ. Structures of the DfsB Protein Family Suggest a Cationic, Helical Sibling Lethal Factor Peptide. J Mol Biol 2016; 428:554-560. [PMID: 26804569 PMCID: PMC4773401 DOI: 10.1016/j.jmb.2016.01.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Revised: 01/07/2016] [Accepted: 01/13/2016] [Indexed: 11/05/2022]
Abstract
Bacteria have developed a variety of mechanisms for surviving harsh environmental conditions, nutrient stress and overpopulation. Paenibacillus dendritiformis produces a lethal protein (Slf) that is able to induce cell death in neighbouring colonies and a phenotypic switch in more distant ones. Slf is derived from the secreted precursor protein, DfsB, after proteolytic processing. Here, we present new crystal structures of DfsB homologues from a variety of bacterial species and a surprising version present in the yeast Saccharomyces cerevisiae. Adopting a four-helix bundle decorated with a further three short helices within intervening loops, DfsB belongs to a non-enzymatic class of the DinB fold. The structure suggests that the biologically active Slf fragment may possess a C-terminal helix rich in basic and aromatic residues that suggest a functional mechanism akin to that for cationic antimicrobial peptides.
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Affiliation(s)
- Jonathan D Taylor
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Gabrielle Taylor
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Stephen A Hare
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Steve J Matthews
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom.
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22
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Microscale kin discrimination in a famous soil bacterium. Proc Natl Acad Sci U S A 2015; 112:13757-8. [DOI: 10.1073/pnas.1519070112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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23
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Smith K, Rajendran R, Kerr S, Lappin DF, Mackay WG, Williams C, Ramage G. Aspergillus fumigatus enhances elastase production in Pseudomonas aeruginosa co-cultures. Med Mycol 2015; 53:645-55. [PMID: 26162475 DOI: 10.1093/mmy/myv048] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 05/25/2015] [Indexed: 02/07/2023] Open
Abstract
In the cystic fibrosis (CF) lung the presence of bacteria and fungi in the airways promotes an inflammatory response causing progressive lung damage, ultimately leading to high rates of morbidity and mortality. We hypothesized that polymicrobial interactions play an important role in promoting airway pathogenesis. We therefore examined the interplay between the most commonly isolated bacterial CF pathogen, Pseudomonas aeruginosa, and the most prevalent filamentous fungi, Aspergillus fumigatus, to test this. Co-culture experiments showed that in the presence of A. fumigatus the production of P. aeruginosa elastase was enhanced. This was confirmed by the presence of zones of clearance on Elastin-Congo Red (ECR) agar, which was identified as elastase by mass spectrometry. When P. aeruginosa were grown in a co-culture model with mature A. fumigatus biofilms, 60% of isolates produced significantly more elastase in the presence of the filamentous fungi than in its absence (P < .05). The expression of lasB also increased when P. aeruginosa isolates PA01 and PA14 were grown in co-culture with A. fumigatus. Supernatants from co-culture experiments were also significantly toxic to a human lung epithelial cell line (19-38% cell cytotoxicity) in comparison to supernatants from P. aeruginosa only cultures (P < .0001). Here we report that P. aeruginosa cytotoxic elastase is enhanced in the presence of the filamentous fungi A. fumigatus, suggesting that this may have a role to play in the damaging pathology associated with the lung tissue in this disease. This indicates that patients who have a co-colonisation with these two organisms may have a poorer prognosis.
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Affiliation(s)
- Karen Smith
- Institute of Healthcare Associated Infection, School of Health, Nursing and Midwifery, University of the West of Scotland, United Kingdom
| | - Ranjith Rajendran
- Infection and Immunity Research Group, Glasgow Dental School, School of Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, United Kingdom
| | - Stephen Kerr
- Infection and Immunity Research Group, Glasgow Dental School, School of Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, United Kingdom
| | - David F Lappin
- Infection and Immunity Research Group, Glasgow Dental School, School of Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, United Kingdom
| | - William G Mackay
- Institute of Healthcare Associated Infection, School of Health, Nursing and Midwifery, University of the West of Scotland, United Kingdom
| | - Craig Williams
- Institute of Healthcare Associated Infection, School of Health, Nursing and Midwifery, University of the West of Scotland, United Kingdom
| | - Gordon Ramage
- Infection and Immunity Research Group, Glasgow Dental School, School of Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, United Kingdom
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24
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Joshi H, Dave R, Venugopalan VP. Protein as chemical cue: non-nutritional growth enhancement by exogenous protein in Pseudomonas putida KT2440. PLoS One 2014; 9:e103730. [PMID: 25117434 PMCID: PMC4130607 DOI: 10.1371/journal.pone.0103730] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Accepted: 07/03/2014] [Indexed: 11/19/2022] Open
Abstract
Research pertaining to microbe-microbe and microbe-plant interactions has been largely limited to small molecules like quorum sensing chemicals. However, a few recent reports have indicated the role of complex molecules like proteins and polysaccharides in microbial communication. Here we demonstrate that exogenous proteins present in culture media can considerably accelerate the growth of Pseudomonas putida KT2440, even when such proteins are not internalized by the cells. The growth enhancement is observed when the exogenous protein is not used as a source of carbon or nitrogen. The data show non-specific nature of the protein inducing growth; growth enhancement was observed irrespective of the protein type. It is shown that growth enhancement is mediated via increased siderophore secretion in response to the exogenous protein, leading to better iron uptake. We highlight the ecological significance of the observation and hypothesize that exogenous proteins serve as chemical cues in the case of P.putida and are perceived as indicator of the presence of competitors in the environment. It is argued that enhanced siderophore secretion in response to exogenous protein helps P.putida establish numerical superiority over competitors by way of enhanced iron assimilation and quicker utilization of aromatic substrates.
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Affiliation(s)
- Hiren Joshi
- Biofouling and Biofilm Processes Section, Water and Steam Chemistry Division, Bhabha Atomic Research Centre, Kalpakkam, India
| | - Rachna Dave
- Biofouling and Biofilm Processes Section, Water and Steam Chemistry Division, Bhabha Atomic Research Centre, Kalpakkam, India
| | - Vayalam P. Venugopalan
- Biofouling and Biofilm Processes Section, Water and Steam Chemistry Division, Bhabha Atomic Research Centre, Kalpakkam, India
- * E-mail:
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25
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van Vliet S, Hol FJH, Weenink T, Galajda P, Keymer JE. The effects of chemical interactions and culture history on the colonization of structured habitats by competing bacterial populations. BMC Microbiol 2014; 14:116. [PMID: 24884963 PMCID: PMC4032360 DOI: 10.1186/1471-2180-14-116] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 05/01/2014] [Indexed: 02/01/2023] Open
Abstract
Background Bacterial habitats, such as soil and the gut, are structured at the micrometer scale. Important aspects of microbial life in such spatial ecosystems are migration and colonization. Here we explore the colonization of a structured ecosystem by two neutrally labeled strains of Escherichia coli. Using time-lapse microscopy we studied the colonization of one-dimensional arrays of habitat patches linked by connectors, which were invaded by the two E. coli strains from opposite sides. Results The two strains colonize a habitat from opposite sides by a series of traveling waves followed by an expansion front. When population waves collide, they branch into a continuing traveling wave, a reflected wave and a stationary population. When the two strains invade the landscape from opposite sides, they remain segregated in space and often one population will displace the other from most of the habitat. However, when the strains are co-cultured before entering the habitats, they colonize the habitat together and do not separate spatially. Using physically separated, but diffusionally coupled, habitats we show that colonization waves and expansion fronts interact trough diffusible molecules, and not by direct competition for space. Furthermore, we found that colonization outcome is influenced by a culture’s history, as the culture with the longest doubling time in bulk conditions tends to take over the largest fraction of the habitat. Finally, we observed that population distributions in parallel habitats located on the same device and inoculated with cells from the same overnight culture are significantly more similar to each other than to patterns in identical habitats located on different devices inoculated with cells from different overnight cultures, even tough all cultures were started from the same −80°C frozen stock. Conclusions We found that the colonization of spatially structure habitats by two interacting populations can lead to the formation of complex, but reproducible, spatiotemporal patterns. Furthermore, we showed that chemical interactions between two populations cause them to remain spatially segregated while they compete for habitat space. Finally, we observed that growth properties in bulk conditions correlate with the outcome of habitat colonization. Together, our data show the crucial roles of chemical interactions between populations and a culture’s history in determining the outcome of habitat colonization.
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Affiliation(s)
- Simon van Vliet
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, Delft, CJ 2628, The Netherlands.
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26
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Weber MF, Poxleitner G, Hebisch E, Frey E, Opitz M. Chemical warfare and survival strategies in bacterial range expansions. J R Soc Interface 2014; 11:20140172. [PMID: 24806706 PMCID: PMC4032534 DOI: 10.1098/rsif.2014.0172] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Dispersal of species is a fundamental ecological process in the evolution and maintenance of biodiversity. Limited control over ecological parameters has hindered progress in understanding of what enables species to colonize new areas, as well as the importance of interspecies interactions. Such control is necessary to construct reliable mathematical models of ecosystems. In our work, we studied dispersal in the context of bacterial range expansions and identified the major determinants of species coexistence for a bacterial model system of three Escherichia coli strains (toxin-producing, sensitive and resistant). Genetic engineering allowed us to tune strain growth rates and to design different ecological scenarios (cyclic and hierarchical). We found that coexistence of all strains depended on three strongly interdependent factors: composition of inoculum, relative strain growth rates and effective toxin range. Robust agreement between our experiments and a thoroughly calibrated computational model enabled us to extrapolate these intricate interdependencies in terms of phenomenological biodiversity laws. Our mathematical analysis also suggested that cyclic dominance between strains is not a prerequisite for coexistence in competitive range expansions. Instead, robust three-strain coexistence required a balance between growth rates and either a reduced initial ratio of the toxin-producing strain, or a sufficiently short toxin range.
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Affiliation(s)
- Markus F Weber
- Arnold Sommerfeld Center for Theoretical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, , Theresienstraße 37, Munich 80333, Germany
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27
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Reiter M, Rulands S, Frey E. Range expansion of heterogeneous populations. PHYSICAL REVIEW LETTERS 2014; 112:148103. [PMID: 24766021 DOI: 10.1103/physrevlett.112.148103] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Indexed: 06/03/2023]
Abstract
Risk spreading in bacterial populations is generally regarded as a strategy to maximize survival. Here, we study its role during range expansion of a genetically diverse population where growth and motility are two alternative traits. We find that during the initial expansion phase fast-growing cells do have a selective advantage. By contrast, asymptotically, generalists balancing motility and reproduction are evolutionarily most successful. These findings are rationalized by a set of coupled Fisher equations complemented by stochastic simulations.
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Affiliation(s)
- Matthias Reiter
- Department of Physics, Arnold-Sommerfeld-Center for Theoretical Physics and Center for NanoScience, Ludwig-Maximilians-Universität München, Theresienstrasse 37, D-80333 München, Germany
| | - Steffen Rulands
- Department of Physics, Arnold-Sommerfeld-Center for Theoretical Physics and Center for NanoScience, Ludwig-Maximilians-Universität München, Theresienstrasse 37, D-80333 München, Germany
| | - Erwin Frey
- Department of Physics, Arnold-Sommerfeld-Center for Theoretical Physics and Center for NanoScience, Ludwig-Maximilians-Universität München, Theresienstrasse 37, D-80333 München, Germany
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28
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Ross-Gillespie A, Kümmerli R. Collective decision-making in microbes. Front Microbiol 2014; 5:54. [PMID: 24624121 PMCID: PMC3939447 DOI: 10.3389/fmicb.2014.00054] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Accepted: 01/27/2014] [Indexed: 12/17/2022] Open
Abstract
Microbes are intensely social organisms that routinely cooperate and coordinate their activities to express elaborate population level phenotypes. Such coordination requires a process of collective decision-making, in which individuals detect and collate information not only from their physical environment, but also from their social environment, in order to arrive at an appropriately calibrated response. Here, we present a conceptual overview of collective decision-making as it applies to all group-living organisms; we introduce key concepts and principles developed in the context of animal and human group decisions; and we discuss, with appropriate examples, the applicability of each of these concepts in microbial contexts. In particular, we discuss the roles of information pooling, control skew, speed vs. accuracy trade-offs, local feedbacks, quorum thresholds, conflicts of interest, and the reliability of social information. We conclude that collective decision-making in microbes shares many features with collective decision-making in higher taxa, and we call for greater integration between this fledgling field and other allied areas of research, including in the humanities and the physical sciences.
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Affiliation(s)
- Adin Ross-Gillespie
- Microbial Evolutionary Ecology, Institute of Plant Biology, University of Zürich Zürich, Switzerland
| | - Rolf Kümmerli
- Microbial Evolutionary Ecology, Institute of Plant Biology, University of Zürich Zürich, Switzerland
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29
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Claessen D, Rozen DE, Kuipers OP, Søgaard-Andersen L, van Wezel GP. Bacterial solutions to multicellularity: a tale of biofilms, filaments and fruiting bodies. Nat Rev Microbiol 2014; 12:115-24. [PMID: 24384602 DOI: 10.1038/nrmicro3178] [Citation(s) in RCA: 275] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Although bacteria frequently live as unicellular organisms, many spend at least part of their lives in complex communities, and some have adopted truly multicellular lifestyles and have abandoned unicellular growth. These transitions to multicellularity have occurred independently several times for various ecological reasons, resulting in a broad range of phenotypes. In this Review, we discuss the strategies that are used by bacteria to form and grow in multicellular structures that have hallmark features of multicellularity, including morphological differentiation, programmed cell death and patterning. In addition, we examine the evolutionary and ecological factors that lead to the wide range of coordinated multicellular behaviours that are observed in bacteria.
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Affiliation(s)
- Dennis Claessen
- 1] Molecular Biotechnology, Institute of Biology Leiden, Leiden University, Sylviusweg 72, P.O. Box 9502, 2300 RA Leiden, The Netherlands. [2]
| | - Daniel E Rozen
- 1] Molecular Biotechnology, Institute of Biology Leiden, Leiden University, Sylviusweg 72, P.O. Box 9502, 2300 RA Leiden, The Netherlands. [2]
| | - Oscar P Kuipers
- 1] Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Linnaeusborg, Nijenborgh 7, 9747 AG, Groningen, The Netherlands. [2] Kluyver Center for Genomics of Industrial Fermentation, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Lotte Søgaard-Andersen
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Strasse 10, 35043, Marburg, Germany
| | - Gilles P van Wezel
- Molecular Biotechnology, Institute of Biology Leiden, Leiden University, Sylviusweg 72, P.O. Box 9502, 2300 RA Leiden, The Netherlands
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30
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Kester JC, Fortune SM. Persisters and beyond: mechanisms of phenotypic drug resistance and drug tolerance in bacteria. Crit Rev Biochem Mol Biol 2013; 49:91-101. [PMID: 24328927 DOI: 10.3109/10409238.2013.869543] [Citation(s) in RCA: 125] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
One of the challenges in clinical infectious diseases is the problem of chronic infections, which can require long durations of antibiotic treatment and often recur. An emerging explanation for the refractoriness of some infections to treatment is the existence of subpopulations of drug tolerant cells. While typically discussed as "persister" cells, it is becoming increasingly clear that there is significant heterogeneity in drug responses within a bacterial population and that multiple mechanisms underlie the emergence of drug tolerant and drug-resistant subpopulations. Many of these parallel mechanisms have been shown to affect drug susceptibility at the level of a whole population. Here we review mechanisms of phenotypic drug tolerance and resistance in bacteria with the goal of providing a framework for understanding the similarities and differences in these cells.
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Affiliation(s)
- Jemila C Kester
- Department of Immunology and Infectious Diseases, Harvard School of Public Health , Boston, MA , USA
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Hebisch E, Knebel J, Landsberg J, Frey E, Leisner M. High variation of fluorescence protein maturation times in closely related Escherichia coli strains. PLoS One 2013; 8:e75991. [PMID: 24155882 PMCID: PMC3796512 DOI: 10.1371/journal.pone.0075991] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 08/22/2013] [Indexed: 02/06/2023] Open
Abstract
Fluorescent proteins (FPs) are widely used in biochemistry, biology and biophysics. For quantitative analysis of gene expression FPs are often used as marking molecules. Therefore, sufficient knowledge of maturation times and their affecting factors is of high interest. Here, we investigate the maturation process of the FPs GFP and mCherry expressed by the three closely related Escherichia coli strains of the Colicin E2 system, a model system for colicinogenic interaction. One strain, the C strain produces Colicin, a toxin to which the S strain is sensitive, and against which the R strain is resistant. Under the growth conditions used in this study, the S and R strain have similar growth rates, as opposed to the C strain whose growth rate is significantly reduced due to the toxin production. In combination with theoretical modelling we studied the maturation kinetics of the two FPs in these strains and could confirm an exponential and sigmoidal maturation kinetic for GFP and mCherry, respectively. Our subsequent quantitative experimental analysis revealed a high variance in maturation times independent of the strain studied. In addition, we determined strain dependent maturation times and maturation behaviour. Firstly, FPs expressed by the S and R strain mature on similar average time-scales as opposed to FPs expressed by the C strain. Secondly, dependencies of maturation time with growth conditions are most pronounced in the GFP expressing C strain: Doubling the growth rate of this C strain results in an increased maturation time by a factor of 1.4. As maturation times can vary even between closely related strains, our data emphasize the importance of profound knowledge of individual strains' maturation times for accurate interpretation of gene expression data.
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Affiliation(s)
- Elke Hebisch
- Department of NanoBiophotonics, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
| | - Johannes Knebel
- Arnold-Sommerfeld-Center for Theoretical Physics and Center for NanoScience, Department of Physics, Ludwig-Maximilians Universität München, München, Germany
| | - Janek Landsberg
- Laboratoire Interdisciplinaire de Physique, Universite Joseph Fourier de Grenoble, Saint Martin d'Heres, France
| | - Erwin Frey
- Arnold-Sommerfeld-Center for Theoretical Physics and Center for NanoScience, Department of Physics, Ludwig-Maximilians Universität München, München, Germany
| | - Madeleine Leisner
- Arnold-Sommerfeld-Center for Theoretical Physics and Center for NanoScience, Department of Physics, Ludwig-Maximilians Universität München, München, Germany
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Othmer HG, Xin X, Xue C. Excitation and adaptation in bacteria-a model signal transduction system that controls taxis and spatial pattern formation. Int J Mol Sci 2013; 14:9205-48. [PMID: 23624608 PMCID: PMC3676780 DOI: 10.3390/ijms14059205] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 03/20/2013] [Accepted: 03/22/2013] [Indexed: 11/16/2022] Open
Abstract
The machinery for transduction of chemotactic stimuli in the bacterium E. coli is one of the most completely characterized signal transduction systems, and because of its relative simplicity, quantitative analysis of this system is possible. Here we discuss models which reproduce many of the important behaviors of the system. The important characteristics of the signal transduction system are excitation and adaptation, and the latter implies that the transduction system can function as a "derivative sensor" with respect to the ligand concentration in that the DC component of a signal is ultimately ignored if it is not too large. This temporal sensing mechanism provides the bacterium with a memory of its passage through spatially- or temporally-varying signal fields, and adaptation is essential for successful chemotaxis. We also discuss some of the spatial patterns observed in populations and indicate how cell-level behavior can be embedded in population-level descriptions.
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Affiliation(s)
- Hans G. Othmer
- School of Mathematics, University of Minnesota, Minneapolis, MN 55455, USA; E-Mail:
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +612-624-8325; Fax: +612-626-2017
| | - Xiangrong Xin
- School of Mathematics, University of Minnesota, Minneapolis, MN 55455, USA; E-Mail:
| | - Chuan Xue
- Department of Mathematics, Ohio State University, Columbus, OH 43210, USA; E-Mail:
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Surface Growth of a Motile Bacterial Population Resembles Growth in a Chemostat. J Mol Biol 2012; 424:180-91. [DOI: 10.1016/j.jmb.2012.09.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 09/02/2012] [Accepted: 09/06/2012] [Indexed: 11/17/2022]
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Pátková I, Cepl JJ, Rieger T, Blahůšková A, Neubauer Z, Markoš A. Developmental plasticity of bacterial colonies and consortia in germ-free and gnotobiotic settings. BMC Microbiol 2012; 12:178. [PMID: 22894147 PMCID: PMC3583141 DOI: 10.1186/1471-2180-12-178] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2012] [Accepted: 07/18/2012] [Indexed: 12/18/2022] Open
Abstract
Background Bacteria grown on semi-solid media can build two types of multicellular structures, depending on the circumstances. Bodies (colonies) arise when a single clone is grown axenically (germ-free), whereas multispecies chimeric consortia contain monoclonal microcolonies of participants. Growth of an axenic colony, mutual interactions of colonies, and negotiation of the morphospace in consortial ecosystems are results of intricate regulatory and metabolic networks. Multicellular structures developed by Serratia sp. are characteristically shaped and colored, forming patterns that reflect their growth conditions (in particular medium composition and the presence of other bacteria). Results Building on our previous work, we developed a model system for studying ontogeny of multicellular bacterial structures formed by five Serratia sp. morphotypes of two species grown in either "germ-free" or "gnotobiotic" settings (i.e. in the presence of bacteria of other conspecific morphotype, other Serratia species, or E. coli). Monoclonal bodies show regular and reproducible macroscopic appearance of the colony, as well as microscopic pattern of its growing margin. Standard development can be modified in a characteristic and reproducible manner in close vicinity of other bacterial structures (or in the presence of their products). Encounters of colonies with neighbors of a different morphotype or species reveal relationships of dominance, cooperation, or submission; multiple interactions can be summarized in "rock – paper – scissors" network of interrelationships. Chimerical (mixed) plantings consisting of two morphotypes usually produced a “consortium” whose structure is consistent with the model derived from interaction patterns observed in colonies. Conclusions Our results suggest that development of a bacterial colony can be considered analogous to embryogenesis in animals, plants, or fungi: to proceed, early stages require thorough insulation from the rest of the biosphere. Only later, the newly developing body gets connected to the ecological interactions in the biosphere. Mixed “anlagen” cannot accomplish the first, germ-free phase of development; hence, they will result in the consortium of small colonies. To map early development and subsequent interactions with the rest of the biospheric web, simplified gnotobiotic systems described here may turn to be of general use, complementing similar studies on developing multicellular eukaryots under germ-free or gnotobiotic conditions.
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Affiliation(s)
- Irena Pátková
- Department of philosophy and history of Science, Faculty of Science, Charles University in Prague, Viničná 7, Praha 2, Czechia
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Mead DA, Lucas S, Copeland A, Lapidus A, Cheng JF, Bruce DC, Goodwin LA, Pitluck S, Chertkov O, Zhang X, Detter JC, Han CS, Tapia R, Land M, Hauser LJ, Chang YJ, Kyrpides NC, Ivanova NN, Ovchinnikova G, Woyke T, Brumm C, Hochstein R, Schoenfeld T, Brumm P. Complete Genome Sequence of Paenibacillus strain Y4.12MC10, a Novel Paenibacillus lautus strain Isolated from Obsidian Hot Spring in Yellowstone National Park. Stand Genomic Sci 2012; 6:381-400. [PMID: 23408395 PMCID: PMC3558958 DOI: 10.4056/sigs.2605792] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Paenibacillus sp.Y412MC10 was one of a number of organisms isolated from Obsidian Hot Spring, Yellowstone National Park, Montana, USA under permit from the National Park Service. The isolate was initially classified as a Geobacillus sp. Y412MC10 based on its isolation conditions and similarity to other organisms isolated from hot springs at Yellowstone National Park. Comparison of 16 S rRNA sequences within the Bacillales indicated that Geobacillus sp.Y412MC10 clustered with Paenibacillus species, and the organism was most closely related to Paenibacillus lautus. Lucigen Corp. prepared genomic DNA and the genome was sequenced, assembled, and annotated by the DOE Joint Genome Institute. The genome sequence was deposited at the NCBI in October 2009 (NC_013406). The genome of Paenibacillus sp. Y412MC10 consists of one circular chromosome of 7,121,665 bp with an average G+C content of 51.2%. Comparison to other Paenibacillus species shows the organism lacks nitrogen fixation, antibiotic production and social interaction genes reported in other paenibacilli. The Y412MC10 genome shows a high level of synteny and homology to the draft sequence of Paenibacillus sp. HGF5, an organism from the Human Microbiome Project (HMP) Reference Genomes. This, combined with genomic CAZyme analysis, suggests an intestinal, rather than environmental origin for Y412MC10.
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Affiliation(s)
- David A. Mead
- Lucigen Corporation, Middleton, Wisconsin
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin, Madison, Wisconsin
| | - Susan Lucas
- DOE Joint Genome Institute, Walnut Creek, California
| | - Alex Copeland
- DOE Joint Genome Institute, Walnut Creek, California
| | - Alla Lapidus
- DOE Joint Genome Institute, Walnut Creek, California
| | | | - David C. Bruce
- DOE Joint Genome Institute, Walnut Creek, California
- Los Alamos National Laboratory, Bioscience Division, Los Alamos, New Mexico
| | - Lynne A. Goodwin
- DOE Joint Genome Institute, Walnut Creek, California
- Los Alamos National Laboratory, Bioscience Division, Los Alamos, New Mexico
| | - Sam Pitluck
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin, Madison, Wisconsin
| | - Olga Chertkov
- DOE Joint Genome Institute, Walnut Creek, California
| | - Xiaojing Zhang
- DOE Joint Genome Institute, Walnut Creek, California
- Los Alamos National Laboratory, Bioscience Division, Los Alamos, New Mexico
| | - John C. Detter
- DOE Joint Genome Institute, Walnut Creek, California
- Los Alamos National Laboratory, Bioscience Division, Los Alamos, New Mexico
| | - Cliff S. Han
- DOE Joint Genome Institute, Walnut Creek, California
- Los Alamos National Laboratory, Bioscience Division, Los Alamos, New Mexico
| | - Roxanne Tapia
- DOE Joint Genome Institute, Walnut Creek, California
- Los Alamos National Laboratory, Bioscience Division, Los Alamos, New Mexico
| | - Miriam Land
- DOE Joint Genome Institute, Walnut Creek, California
- Oak Ridge National Laboratory, Oak Ridge, Tennessee
| | - Loren J. Hauser
- DOE Joint Genome Institute, Walnut Creek, California
- Oak Ridge National Laboratory, Oak Ridge, Tennessee
| | | | | | | | | | - Tanja Woyke
- DOE Joint Genome Institute, Walnut Creek, California
| | | | | | | | - Phillip Brumm
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin, Madison, Wisconsin
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Ben-Jacob E, Coffey DS, Levine H. Bacterial survival strategies suggest rethinking cancer cooperativity. Trends Microbiol 2012; 20:403-10. [PMID: 22750098 DOI: 10.1016/j.tim.2012.06.001] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Revised: 05/26/2012] [Accepted: 06/01/2012] [Indexed: 02/08/2023]
Abstract
Despite decades of a much improved understanding of cancer biology, we are still baffled by questions regarding the deadliest traits of malignancy: metastatic colonization, dormancy and relapse, and the rapid evolution of multiple drug and immune resistance. New ideas are needed to resolve these critical issues. Relying on finding and demonstrating parallels between collective behavior capabilities of cancer cells and that of bacteria, we suggest communal behaviors of bacteria as a valuable model system for new perspectives and research directions. Understanding the ways in which bacteria thrive in competitive habitats and their cooperative strategies for surviving extreme stress can shed light on cooperativity in tumorigenesis and portray tumors as societies of smart communicating cells. This may translate into progress in fathoming cancer pathogenesis. We outline new experiments to test the cancer cooperativity hypothesis and reason that cancer may be outsmarted through its own 'social intelligence'.
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Affiliation(s)
- Eshel Ben-Jacob
- School of Physics and Astronomy, The Raymond and Beverly Sackler Faculty of Exact Sciences, Tel-Aviv University, Tel-Aviv 69978, Israel.
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Abstract
Recognition of relatives is important in microbes because they perform many behaviors that have costs to the actor while benefiting neighbors. Microbes cooperate for nourishment, movement, virulence, iron acquisition, protection, quorum sensing, and production of multicellular biofilms or fruiting bodies. Helping others is evolutionarily favored if it benefits others who share genes for helping, as specified by kin selection theory. If microbes generally find themselves in clonal patches, then no special means of discrimination is necessary. Much real discrimination is actually of kinds, not kin, as in poison-antidote systems, such as bacteriocins, in which cells benefit their own kind by poisoning others, and in adhesion systems, in which cells of the same kind bind together. These behaviors can elevate kinship generally and make cooperation easier to evolve and maintain.
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Affiliation(s)
- Joan E Strassmann
- Department of Ecology and Evolutionary Biology, Rice University, Houston, Texas 77005, USA.
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Bucci V, Nadell CD, Xavier JB. The evolution of bacteriocin production in bacterial biofilms. Am Nat 2011; 178:E162-73. [PMID: 22089878 DOI: 10.1086/662668] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Bacteriocin production is a spiteful behavior of bacteria that is central to the competitive dynamics of many human pathogens. Social evolution predicts that bacteriocin production is favored when bacteriocin-producing cells are mixed at intermediate frequency with their competitors and when competitive neighborhoods are localized. Both predictions are supported by biofilm experiments. However, the means by which physical and biological processes interact to produce conditions that favor the evolution of bacteriocin production remain to be investigated. Here we fill this gap using analytical and computational approaches. We identify and collapse key parameters into a single number, the critical bacteriocin range, that measures the threshold distance from a focal bacteriocin-producing cell within which its fitness is higher than that of a sensitive cell. We develop an agent-based model to test our predictions and confirm that bacteriocin production is most favored when relatedness is intermediate and competition is local. We then use invasion analysis to determine evolutionarily stable strategies for bacteriocin production. Finally, we perform long-term evolutionary simulations to analyze how the critical bacteriocin range and genetic lineage segregation affect biodiversity in multistrain biofilms. We find that biodiversity is maintained in highly segregated biofilms for a wide array of critical bacteriocin ranges. However, under conditions of high nutrient penetration leading to well-mixed biofilms, biodiversity rapidly decreases and becomes sensitive to the critical bacteriocin range.
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Affiliation(s)
- Vanni Bucci
- Program in Computational Biology, Memorial Sloan-Kettering Cancer Center, New York, New York 10065, USA
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Surviving bacterial sibling rivalry: inducible and reversible phenotypic switching in Paenibacillus dendritiformis. mBio 2011; 2:e00069-11. [PMID: 21628502 PMCID: PMC3104493 DOI: 10.1128/mbio.00069-11] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Natural habitats vary in available nutrients and room for bacteria to grow, but successful colonization can lead to overcrowding and stress. Here we show that competing sibling colonies of Paenibacillus dendritiformis bacteria survive overcrowding by switching between two distinct vegetative phenotypes, motile rods and immotile cocci. Growing colonies of the rod-shaped bacteria produce a toxic protein, Slf, which kills cells of encroaching sibling colonies. However, sublethal concentrations of Slf induce some of the rods to switch to Slf-resistant cocci, which have distinct metabolic and resistance profiles, including resistance to cell wall antibiotics. Unlike dormant spores of P. dendritiformis, the cocci replicate. If cocci encounter conditions that favor rods, they secrete a signaling molecule that induces a switch to rods. Thus, in contrast to persister cells, P. dendritiformis bacteria adapt to changing environmental conditions by inducible and reversible phenotypic switching. In favorable environments, species may face space and nutrient limits due to overcrowding. Bacteria provide an excellent model for analyzing principles underlying overcrowding and regulation of density in nature, since their population dynamics can be easily and accurately assessed under controlled conditions. We describe a newly discovered mechanism for survival of a bacterial population during overcrowding. When competing with sibling colonies, Paenibacillus dendritiformis produces a lethal protein (Slf) that kills cells at the interface of encroaching colonies. Slf also induces a small proportion of the cells to switch from motile, rod-shaped cells to nonmotile, Slf-resistant, vegetative cocci. When crowding is reduced and nutrients are no longer limiting, the bacteria produce a signal that induces cocci to switch back to motile rods, allowing the population to spread. Genes encoding components of this phenotypic switching pathway are widespread among bacterial species, suggesting that this survival mechanism is not unique to P. dendritiformis.
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