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Ábrahám Á, Dér L, Csákvári E, Vizsnyiczai G, Pap I, Lukács R, Varga-Zsíros V, Nagy K, Galajda P. Single-cell level LasR-mediated quorum sensing response of Pseudomonas aeruginosa to pulses of signal molecules. Sci Rep 2024; 14:16181. [PMID: 39003361 PMCID: PMC11246452 DOI: 10.1038/s41598-024-66706-6] [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: 09/04/2023] [Accepted: 07/03/2024] [Indexed: 07/15/2024] Open
Abstract
Quorum sensing (QS) is a communication form between bacteria via small signal molecules that enables global gene regulation as a function of cell density. We applied a microfluidic mother machine to study the kinetics of the QS response of Pseudomonas aeruginosa bacteria to additions and withdrawals of signal molecules. We traced the fast buildup and the subsequent considerably slower decay of a population-level and single-cell-level QS response. We applied a mathematical model to explain the results quantitatively. We found significant heterogeneity in QS on the single-cell level, which may result from variations in quorum-controlled gene expression and protein degradation. Heterogeneity correlates with cell lineage history, too. We used single-cell data to define and quantitatively characterize the population-level quorum state. We found that the population-level QS response is well-defined. The buildup of the quorum is fast upon signal molecule addition. At the same time, its decay is much slower following signal withdrawal, and the quorum may be maintained for several hours in the absence of the signal. Furthermore, the quorum sensing response of the population was largely repeatable in subsequent pulses of signal molecules.
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Affiliation(s)
- Ágnes Ábrahám
- HUN-REN Biological Research Centre, Institute of Biophysics, Temesvári Krt. 62, Szeged, 6726, Hungary
- Doctoral School of Multidisciplinary Medical Sciences, University of Szeged, Dóm Tér 9, Szeged, 6720, Hungary
| | - László Dér
- HUN-REN Biological Research Centre, Institute of Biophysics, Temesvári Krt. 62, Szeged, 6726, Hungary
| | - Eszter Csákvári
- HUN-REN Biological Research Centre, Institute of Biophysics, Temesvári Krt. 62, Szeged, 6726, Hungary
- Division for Biotechnology, Bay Zoltán Nonprofit Ltd. for Applied Research, Derkovits Fasor 2., Szeged, 6726, Hungary
| | - Gaszton Vizsnyiczai
- HUN-REN Biological Research Centre, Institute of Biophysics, Temesvári Krt. 62, Szeged, 6726, Hungary
| | - Imre Pap
- HUN-REN Biological Research Centre, Institute of Biophysics, Temesvári Krt. 62, Szeged, 6726, Hungary
- Doctoral School of Multidisciplinary Medical Sciences, University of Szeged, Dóm Tér 9, Szeged, 6720, Hungary
| | - Rebeka Lukács
- HUN-REN Biological Research Centre, Institute of Biophysics, Temesvári Krt. 62, Szeged, 6726, Hungary
| | - Vanda Varga-Zsíros
- HUN-REN Biological Research Centre, Institute of Biophysics, Temesvári Krt. 62, Szeged, 6726, Hungary
- HUN-REN Biological Research Centre, Institute of Biochemistry, Temesvári Krt. 62, Szeged, 6726, Hungary
| | - Krisztina Nagy
- HUN-REN Biological Research Centre, Institute of Biophysics, Temesvári Krt. 62, Szeged, 6726, Hungary.
| | - Péter Galajda
- HUN-REN Biological Research Centre, Institute of Biophysics, Temesvári Krt. 62, Szeged, 6726, Hungary.
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Liu D, Han Z, Hu Z, Yu C, Wang Y, Tong J, Fang X, Yue W, Nie G. Comparative analysis of the transcriptome of Bacillus subtilis natto incubated in different substrates for nattokinase production. Process Biochem 2023. [DOI: 10.1016/j.procbio.2023.03.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
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3
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Huang Y, Flint SH, Palmer JS. The heat resistance of spores from biofilms of Bacillus cereus grown in tryptic soy broth and milk. Int Dairy J 2021. [DOI: 10.1016/j.idairyj.2021.105169] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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4
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Wang N, Jin Y, He G, Yuan L. Intraspecific and interspecific extracellular metabolites remodel biofilms formed by thermophilic spoilage bacteria. J Appl Microbiol 2021; 133:2096-2106. [PMID: 34689405 DOI: 10.1111/jam.15338] [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: 07/14/2021] [Revised: 09/24/2021] [Accepted: 10/17/2021] [Indexed: 11/30/2022]
Abstract
AIMS Thermophilic spoilage bacteria and their biofilms formed during milk powder processing posed threats to safety and quality of dairy products. This research aims to understand more about the bacterial behaviours and their social models in biofilms. METHODS AND RESULTS Interactional effects from both extracellular metabolites and co-culture on biofilms formation of the contaminating thermophilic bacteria were determined. The results showed that strong biofilm formers always had high AI-2 activities, including Geobacillus stearothermophilus gs1, Bacillus licheniformis bl1 and Thermoactinomyces vulgaris tv1. Metabolites from themself or other species altered their biofilm biomass detected by crystal violet staining. Dual-species cultures observed by confocal laser scanning microscope indicated either synergistic or inhibitory effects between B. circulans bc1 and G. stearothermophilus gs1, as well as B. licheniformis bl1 and G. stearothermophilus gs1. Fourier transform infrared spectrometry results revealed the significant diversities in polysaccharides of the biofilm matrix. CONCLUSIONS Cell communication played an important role on biofilm formation in the complex microbial community. Intraspecific and interspecific extracellular metabolites influenced collective bacterial behaviours under mixed circumstances. SIGNIFICANCE AND IMPACT OF STUDY This research provided evidences on cell communication and biofilm formation of thermophilic bacteria in dairy industry.
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Affiliation(s)
- Ni Wang
- School of Chemical and Environmental Engineering, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, China
| | - Yujie Jin
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, China
| | - Guoqing He
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, China
| | - Lei Yuan
- College of Food Science and Engineering, Yangzhou University, Yangzhou, China
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van Gestel J, Wagner A. Cryptic surface-associated multicellularity emerges through cell adhesion and its regulation. PLoS Biol 2021; 19:e3001250. [PMID: 33983920 PMCID: PMC8148357 DOI: 10.1371/journal.pbio.3001250] [Citation(s) in RCA: 4] [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: 01/10/2021] [Revised: 05/25/2021] [Accepted: 04/28/2021] [Indexed: 12/20/2022] Open
Abstract
The repeated evolution of multicellularity led to a wide diversity of organisms, many of which are sessile, including land plants, many fungi, and colonial animals. Sessile organisms adhere to a surface for most of their lives, where they grow and compete for space. Despite the prevalence of surface-associated multicellularity, little is known about its evolutionary origin. Here, we introduce a novel theoretical approach, based on spatial lineage tracking of cells, to study this origin. We show that multicellularity can rapidly evolve from two widespread cellular properties: cell adhesion and the regulatory control of adhesion. By evolving adhesion, cells attach to a surface, where they spontaneously give rise to primitive cell collectives that differ in size, life span, and mode of propagation. Selection in favor of large collectives increases the fraction of adhesive cells until a surface becomes fully occupied. Through kin recognition, collectives then evolve a central-peripheral polarity in cell adhesion that supports a division of labor between cells and profoundly impacts growth. Despite this spatial organization, nascent collectives remain cryptic, lack well-defined boundaries, and would require experimental lineage tracking technologies for their identification. Our results suggest that cryptic multicellularity could readily evolve and originate well before multicellular individuals become morphologically evident.
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Affiliation(s)
- Jordi van Gestel
- Department of Evolutionary Biology and Environmental Studies, University of Zürich, Zürich, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Andreas Wagner
- Department of Evolutionary Biology and Environmental Studies, University of Zürich, Zürich, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
- The Santa Fe Institute, Santa Fe, New Mexico, United States of America
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6
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Phenotypic properties and genotyping analysis of Bacillus cereus group isolates from dairy and potato products. Lebensm Wiss Technol 2021. [DOI: 10.1016/j.lwt.2021.110853] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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Huang Y, Flint SH, Palmer JS. Bacillus cereus spores and toxins – The potential role of biofilms. Food Microbiol 2020; 90:103493. [DOI: 10.1016/j.fm.2020.103493] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 03/18/2020] [Accepted: 03/20/2020] [Indexed: 01/19/2023]
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8
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Francisco CS, Zwyssig MM, Palma-Guerrero J. The role of vegetative cell fusions in the development and asexual reproduction of the wheat fungal pathogen Zymoseptoria tritici. BMC Biol 2020; 18:99. [PMID: 32782023 PMCID: PMC7477884 DOI: 10.1186/s12915-020-00838-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Accepted: 07/27/2020] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND The ability of fungal cells to undergo cell-to-cell communication and anastomosis, the process of vegetative hyphal fusion, allows them to maximize their overall fitness. Previous studies in a number of fungal species have identified the requirement of several signaling pathways for anastomosis, including the so far best characterized soft (So) gene, and the MAPK pathway components MAK-1 and MAK-2 of Neurospora crassa. Despite the observations of hyphal fusions' involvement in pathogenicity and host adhesion, the connection between cell fusion and fungal lifestyles is still unclear. Here, we address the role of anastomosis in fungal development and asexual reproduction in Zymoseptoria tritici, the most important fungal pathogen of wheat in Europe. RESULTS We show that Z. tritici undergoes self-fusion between distinct cellular structures, and its mechanism is dependent on the initial cell density. Contrary to other fungi, cell fusion in Z. tritici only resulted in cytoplasmic mixing but not in multinucleated cell formation. The deletion of the So orthologous ZtSof1 disrupted cell-to-cell communication affecting both hyphal and germling fusion. We show that Z. tritici mutants for MAPK-encoding ZtSlt2 (orthologous to MAK-1) and ZtFus3 (orthologous to MAK-2) genes also failed to undergo anastomosis, demonstrating the functional conservation of this signaling mechanism across species. Additionally, the ΔZtSof1 mutant was severely impaired in melanization, suggesting that the So gene function is related to melanization. Finally, we demonstrated that anastomosis is dispensable for pathogenicity, but essential for the pycnidium development, and its absence abolishes the asexual reproduction of Z. tritici. CONCLUSIONS We demonstrate the role for ZtSof1, ZtSlt2, and ZtFus3 in cell fusions of Z. tritici. Cell fusions are essential for different aspects of the Z. tritici biology, and the ZtSof1 gene is a potential target to control septoria tritici blotch (STB) disease.
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Affiliation(s)
| | - Maria Manuela Zwyssig
- Plant Pathology Group, Institute of Integrative Biology, ETH Zürich, 8092, Zürich, Switzerland
| | - Javier Palma-Guerrero
- Plant Pathology Group, Institute of Integrative Biology, ETH Zürich, 8092, Zürich, Switzerland.
- New Address: Department of Biointeractions and Crop Protection, Rothamsted Research, Harpenden, UK.
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Kan A, Del Valle I, Rudge T, Federici F, Haseloff J. Intercellular adhesion promotes clonal mixing in growing bacterial populations. J R Soc Interface 2018; 15:rsif.2018.0406. [PMID: 30232243 PMCID: PMC6170782 DOI: 10.1098/rsif.2018.0406] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2018] [Accepted: 08/28/2018] [Indexed: 12/22/2022] Open
Abstract
Dense bacterial communities, known as biofilms, can have functional spatial organization driven by self-organizing chemical and physical interactions between cells, and their environment. In this work, we investigated intercellular adhesion, a pervasive property of bacteria in biofilms, to identify effects on the internal structure of bacterial colonies. We expressed the self-recognizing ag43 adhesin protein in Escherichia coli to generate adhesion between cells, which caused aggregation in liquid culture and altered microcolony morphology on solid media. We combined the adhesive phenotype with an artificial colony patterning system based on plasmid segregation, which marked clonal lineage domains in colonies grown from single cells. Engineered E. coli were grown to colonies containing domains with varying adhesive properties, and investigated with microscopy, image processing and computational modelling techniques. We found that intercellular adhesion elongated the fractal-like boundary between cell lineages only when both domains within the colony were adhesive, by increasing the rotational motion during colony growth. Our work demonstrates that adhesive intercellular interactions can have significant effects on the spatial organization of bacterial populations, which can be exploited for biofilm engineering. Furthermore, our approach provides a robust platform to study the influence of intercellular interactions on spatial structure in bacterial populations.
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Affiliation(s)
- Anton Kan
- Department of Plant Sciences, University of Cambridge, Cambridge, UK
| | - Ilenne Del Valle
- Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Tim Rudge
- Institute for Biological and Medical Engineering, Schools of Engineering, Biology and Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile.,Department of Chemical and Bioprocess Engineering, School of Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Fernán Federici
- Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.,Fondo de Desarrollo de Áreas Prioritarias, Center for Genome Regulation, Millennium Institute for Integrative Systems and Synthetic Biology (MIISSB), Santiago, Chile
| | - Jim Haseloff
- Department of Plant Sciences, University of Cambridge, Cambridge, UK
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10
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On the origin of biological construction, with a focus on multicellularity. Proc Natl Acad Sci U S A 2017; 114:11018-11026. [PMID: 28973893 DOI: 10.1073/pnas.1704631114] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Biology is marked by a hierarchical organization: all life consists of cells; in some cases, these cells assemble into groups, such as endosymbionts or multicellular organisms; in turn, multicellular organisms sometimes assemble into yet other groups, such as primate societies or ant colonies. The construction of new organizational layers results from hierarchical evolutionary transitions, in which biological units (e.g., cells) form groups that evolve into new units of biological organization (e.g., multicellular organisms). Despite considerable advances, there is no bottom-up, dynamical account of how, starting from the solitary ancestor, the first groups originate and subsequently evolve the organizing principles that qualify them as new units. Guided by six central questions, we propose an integrative bottom-up approach for studying the dynamics underlying hierarchical evolutionary transitions, which builds on and synthesizes existing knowledge. This approach highlights the crucial role of the ecology and development of the solitary ancestor in the emergence and subsequent evolution of groups, and it stresses the paramount importance of the life cycle: only by evaluating groups in the context of their life cycle can we unravel the evolutionary trajectory of hierarchical transitions. These insights also provide a starting point for understanding the types of subsequent organizational complexity. The central research questions outlined here naturally link existing research programs on biological construction (e.g., on cooperation, multilevel selection, self-organization, and development) and thereby help integrate knowledge stemming from diverse fields of biology.
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11
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Mathematical Modelling of Bacterial Quorum Sensing: A Review. Bull Math Biol 2016; 78:1585-639. [PMID: 27561265 DOI: 10.1007/s11538-016-0160-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 03/15/2016] [Indexed: 12/21/2022]
Abstract
Bacterial quorum sensing (QS) refers to the process of cell-to-cell bacterial communication enabled through the production and sensing of the local concentration of small molecules called autoinducers to regulate the production of gene products (e.g. enzymes or virulence factors). Through autoinducers, bacteria interact with individuals of the same species, other bacterial species, and with their host. Among QS-regulated processes mediated through autoinducers are aggregation, biofilm formation, bioluminescence, and sporulation. Autoinducers are therefore "master" regulators of bacterial lifestyles. For over 10 years, mathematical modelling of QS has sought, in parallel to experimental discoveries, to elucidate the mechanisms regulating this process. In this review, we present the progress in mathematical modelling of QS, highlighting the various theoretical approaches that have been used and discussing some of the insights that have emerged. Modelling of QS has benefited almost from the onset of the involvement of experimentalists, with many of the papers which we review, published in non-mathematical journals. This review therefore attempts to give a broad overview of the topic to the mathematical biology community, as well as the current modelling efforts and future challenges.
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12
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van Gestel J, Weissing FJ. Regulatory mechanisms link phenotypic plasticity to evolvability. Sci Rep 2016; 6:24524. [PMID: 27087393 PMCID: PMC4834480 DOI: 10.1038/srep24524] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 03/30/2016] [Indexed: 12/26/2022] Open
Abstract
Organisms have a remarkable capacity to respond to environmental change. They can either respond directly, by means of phenotypic plasticity, or they can slowly adapt through evolution. Yet, how phenotypic plasticity links to evolutionary adaptability is largely unknown. Current studies of plasticity tend to adopt a phenomenological reaction norm (RN) approach, which neglects the mechanisms underlying plasticity. Focusing on a concrete question - the optimal timing of bacterial sporulation - we here also consider a mechanistic approach, the evolution of a gene regulatory network (GRN) underlying plasticity. Using individual-based simulations, we compare the RN and GRN approach and find a number of striking differences. Most importantly, the GRN model results in a much higher diversity of responsive strategies than the RN model. We show that each of the evolved strategies is pre-adapted to a unique set of unseen environmental conditions. The regulatory mechanisms that control plasticity therefore critically link phenotypic plasticity to the adaptive potential of biological populations.
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Affiliation(s)
- Jordi van Gestel
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, P.O. Box 11103, Groningen 9700 CC, The Netherlands
| | - Franz J. Weissing
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, P.O. Box 11103, Groningen 9700 CC, The Netherlands
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13
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Abstract
The dense aggregation of cells on a surface, as seen in biofilms, inevitably results in both environmental and cellular heterogeneity. For example, nutrient gradients can trigger cells to differentiate into various phenotypic states. Not only do cells adapt physiologically to the local environmental conditions, but they also differentiate into cell types that interact with each other. This allows for task differentiation and, hence, the division of labor. In this article, we focus on cell differentiation and the division of labor in three bacterial species: Myxococcus xanthus, Bacillus subtilis, and Pseudomonas aeruginosa. During biofilm formation each of these species differentiates into distinct cell types, in some cases leading to cooperative interactions. The division of labor and the cooperative interactions between cell types are assumed to yield an emergent ecological benefit. Yet in most cases the ecological benefits have yet to be elucidated. A notable exception is M. xanthus, in which cell differentiation within fruiting bodies facilitates the dispersal of spores. We argue that the ecological benefits of the division of labor might best be understood when we consider the dynamic nature of both biofilm formation and degradation.
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14
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Dall SRX, McNamara JM, Leimar O. Genes as cues: phenotypic integration of genetic and epigenetic information from a Darwinian perspective. Trends Ecol Evol 2015; 30:327-33. [PMID: 25944666 DOI: 10.1016/j.tree.2015.04.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 04/07/2015] [Accepted: 04/08/2015] [Indexed: 10/23/2022]
Abstract
The development of multicellular organisms involves a delicate interplay between genetic and environmental influences. It is often useful to think of developmental systems as integrating available sources of information about current conditions to produce organisms. Genes and inherited physiology provide cues, as does the state of the environment during development. The integration systems themselves are under genetic control and subject to Darwinian selection, so we expect them to evolve to produce organisms that fit well with current ecological (including social) conditions. We argue for the scientific value of this explicitly informational perspective by providing detailed examples of how it can elucidate taxonomically diverse phenomena. We also present a general framework for linking genetic and phenotypic variation from an informational perspective. This application of Darwinian logic at the organismal level can elucidate genetic influences on phenotypic variation in novel and counterintuitive ways.
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Affiliation(s)
- Sasha R X Dall
- Centre for Ecology and Conservation, Biosciences, College of Life and Environmental Sciences, University of Exeter, Penryn Campus, Tremough, Penryn TR10 9EZ, UK.
| | - John M McNamara
- Centre for Ecology and Conservation, Biosciences, College of Life and Environmental Sciences, University of Exeter, Penryn Campus, Tremough, Penryn TR10 9EZ, UK; School of Mathematics, University of Bristol, University Walk, Bristol BS8 1TW, UK
| | - Olof Leimar
- Department of Zoology, Stockholm University, SE-106 91 Stockholm, Sweden
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15
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Phaiboun A, Zhang Y, Park B, Kim M. Survival kinetics of starving bacteria is biphasic and density-dependent. PLoS Comput Biol 2015; 11:e1004198. [PMID: 25838110 PMCID: PMC4383377 DOI: 10.1371/journal.pcbi.1004198] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 02/16/2015] [Indexed: 11/19/2022] Open
Abstract
In the lifecycle of microorganisms, prolonged starvation is prevalent and sustaining life during starvation periods is a vital task. In the literature, it is commonly assumed that survival kinetics of starving microbes follows exponential decay. This assumption, however, has not been rigorously tested. Currently, it is not clear under what circumstances this assumption is true. Also, it is not known when such survival kinetics deviates from exponential decay and if it deviates, what underlying mechanisms for the deviation are. Here, to address these issues, we quantitatively characterized dynamics of survival and death of starving E. coli cells. The results show that the assumption--starving cells die exponentially--is true only at high cell density. At low density, starving cells persevere for extended periods of time, before dying rapidly exponentially. Detailed analyses show intriguing quantitative characteristics of the density-dependent and biphasic survival kinetics, including that the period of the perseverance is inversely proportional to cell density. These characteristics further lead us to identification of key underlying processes relevant for the perseverance of starving cells. Then, using mathematical modeling, we show how these processes contribute to the density-dependent and biphasic survival kinetics observed. Importantly, our model reveals a thrifty strategy employed by bacteria, by which upon sensing impending depletion of a substrate, the limiting substrate is conserved and utilized later during starvation to delay cell death. These findings advance quantitative understanding of survival of microbes in oligotrophic environments and facilitate quantitative analysis and prediction of microbial dynamics in nature. Furthermore, they prompt revision of previous models used to analyze and predict population dynamics of microbes.
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Affiliation(s)
- Andy Phaiboun
- Department of Physics, Emory University, Atlanta, Georgia, United States of America
| | - Yiming Zhang
- Department of Physics, Emory University, Atlanta, Georgia, United States of America
| | - Boryung Park
- Department of Physics, Emory University, Atlanta, Georgia, United States of America
| | - Minsu Kim
- Department of Physics, Emory University, Atlanta, Georgia, United States of America
- Graduate Division of Biological and Biomedical Sciences, Emory University, Atlanta, Georgia, United States of America
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16
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A mathematical model to investigate quorum sensing regulation and its heterogeneity in Pseudomonas syringae on leaves. ECOLOGICAL COMPLEXITY 2015. [DOI: 10.1016/j.ecocom.2014.12.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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17
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Pacheco JM, Vasconcelos VV, Santos FC, Skyrms B. Co-evolutionary dynamics of collective action with signaling for a quorum. PLoS Comput Biol 2015; 11:e1004101. [PMID: 25706984 PMCID: PMC4338077 DOI: 10.1371/journal.pcbi.1004101] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 12/19/2014] [Indexed: 12/21/2022] Open
Abstract
Collective signaling for a quorum is found in a wide range of organisms that face collective action problems whose successful solution requires the participation of some quorum of the individuals present. These range from humans, to social insects, to bacteria. The mechanisms involved, the quorum required, and the size of the group may vary. Here we address the general question of the evolution of collective signaling at a high level of abstraction. We investigate the evolutionary dynamics of a population engaging in a signaling N-person game theoretic model. Parameter settings allow for loners and cheaters, and for costly or costless signals. We find a rich dynamics, showing how natural selection, operating on a population of individuals endowed with the simplest strategies, is able to evolve a costly signaling system that allows individuals to respond appropriately to different states of Nature. Signaling robustly promotes cooperative collective action, in particular when coordinated action is most needed and difficult to achieve. Two different signaling systems may emerge depending on Nature's most prevalent states.
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Affiliation(s)
- Jorge M. Pacheco
- Centro de Biologia Molecular e Ambiental, Universidade do Minho, Braga, Portugal
- Departamento de Matemática e Aplicações, Universidade do Minho, Braga, Portugal
- ATP-Group, CMAF, Instituto para a Investigação Interdisciplinar, Lisboa, Portugal
- * E-mail:
| | - Vítor V. Vasconcelos
- ATP-Group, CMAF, Instituto para a Investigação Interdisciplinar, Lisboa, Portugal
- Centro de Física da Universidade do Minho, Braga, Portugal
- INESC-ID and Instituto Superior Técnico, Universidade de Lisboa, IST-Taguspark, Porto Salvo, Portugal
| | - Francisco C. Santos
- ATP-Group, CMAF, Instituto para a Investigação Interdisciplinar, Lisboa, Portugal
- INESC-ID and Instituto Superior Técnico, Universidade de Lisboa, IST-Taguspark, Porto Salvo, Portugal
| | - Brian Skyrms
- Logic and Philosophy of Science, School of Social Sciences, University of California at Irvine, Irvine, California, United States of America
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Hayrapetyan H, Muller L, Tempelaars M, Abee T, Nierop Groot M. Comparative analysis of biofilm formation by Bacillus cereus reference strains and undomesticated food isolates and the effect of free iron. Int J Food Microbiol 2015; 200:72-9. [PMID: 25700364 DOI: 10.1016/j.ijfoodmicro.2015.02.005] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 11/17/2014] [Accepted: 02/04/2015] [Indexed: 10/24/2022]
Abstract
Biofilm formation of Bacillus cereus reference strains ATCC 14579 and ATCC 10987 and 21 undomesticated food isolates was studied on polystyrene and stainless steel as contact surfaces. For all strains, the biofilm forming capacity was significantly enhanced when in contact with stainless steel (SS) as a surface as compared to polystyrene (PS). For a selection of strains, the total CFU and spore counts in biofilms were determined and showed a good correlation between CFU counts and total biomass of these biofilms. Sporulation was favoured in the biofilm over the planktonic state. To substantiate whether iron availability could affect B. cereus biofilm formation, the free iron availability was varied in BHI by either the addition of FeCl3 or by depletion of iron with the scavenger 2,2-Bipyridine. Addition of iron resulted in increased air-liquid interface biofilm on polystyrene but not on SS for strain ATCC 10987, while the presence of Bipyridine reduced biofilm formation for both materials. Biofilm formation was restored when excess FeCl3 was added in combination with the scavenger. Further validation of the iron effect for all 23 strains in microtiter plate showed that fourteen strains (including ATCC10987) formed a biofilm on PS. For eight of these strains biofilm formation was enhanced in the presence of added iron and for eleven strains it was reduced when free iron was scavenged. Our results show that stainless steel as a contact material provides more favourable conditions for B. cereus biofilm formation and maturation compared to polystyrene. This effect could possibly be linked to iron availability as we show that free iron availability affects B. cereus biofilm formation.
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Affiliation(s)
- Hasmik Hayrapetyan
- Laboratory of Food Microbiology, Bornse Weilanden 9, 6708 WG Wageningen University, Wageningen, The Netherlands; Top Institute of Food and Nutrition (TIFN), Nieuwe Kanaal 9A, 6709 PA Wageningen, The Netherlands
| | - Lisette Muller
- Laboratory of Food Microbiology, Bornse Weilanden 9, 6708 WG Wageningen University, Wageningen, The Netherlands
| | - Marcel Tempelaars
- Laboratory of Food Microbiology, Bornse Weilanden 9, 6708 WG Wageningen University, Wageningen, The Netherlands; Top Institute of Food and Nutrition (TIFN), Nieuwe Kanaal 9A, 6709 PA Wageningen, The Netherlands
| | - Tjakko Abee
- Laboratory of Food Microbiology, Bornse Weilanden 9, 6708 WG Wageningen University, Wageningen, The Netherlands; Top Institute of Food and Nutrition (TIFN), Nieuwe Kanaal 9A, 6709 PA Wageningen, The Netherlands.
| | - Masja Nierop Groot
- Top Institute of Food and Nutrition (TIFN), Nieuwe Kanaal 9A, 6709 PA Wageningen, The Netherlands; Food and Biobased Research, Wageningen UR, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands
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Chen J, Ma M, Uzal FA, McClane BA. Host cell-induced signaling causes Clostridium perfringens to upregulate production of toxins important for intestinal infections. Gut Microbes 2014; 5:96-107. [PMID: 24061146 PMCID: PMC4049945 DOI: 10.4161/gmic.26419] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Clostridium perfringens causes enteritis and enterotoxemia in humans and livestock due to prolific toxin production. In broth culture, C. perfringens uses the Agr-like quorum sensing (QS) system to regulate production of toxins important for enteritis/enterotoxemia, including beta toxin (CPB), enterotoxin, and epsilon toxin (ETX). The VirS/VirR two-component regulatory system (TCRS) also controls CPB production in broth cultures. Both the Agr-like QS and VirS/VirR systems are important when C. perfringens senses enterocyte-like Caco-2 cells and responds by upregulating CPB production; however, only the Agr-like QS system is needed for host cell-induced ETX production. These in vitro observations have pathophysiologic relevance since both the VirS/VirR and Agr-like QS signaling systems are required for C. perfringens strain CN3685 to produce CPB in vivo and to cause enteritis or enterotoxemia. Thus, apparently upon sensing its presence in the intestines, C. perfringens utilizes QS and TCRS signaling to produce toxins necessary for intestinal virulence.
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Affiliation(s)
- Jianming Chen
- Department of Microbiology and Molecular Genetics; University of Pittsburgh School of Medicine; Pittsburgh, PA USA
| | - Menglin Ma
- Department of Microbiology and Molecular Genetics; University of Pittsburgh School of Medicine; Pittsburgh, PA USA
| | - Francisco A Uzal
- California Animal Health and Food Safety Laboratory; San Bernadino Branch, School of Veterinary Medicine; University of California Davis; San Bernadino, CA USA
| | - Bruce A McClane
- Department of Microbiology and Molecular Genetics; University of Pittsburgh School of Medicine; Pittsburgh, PA USA,Correspondence to: Bruce A McClane,
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