1
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Beaussart A, Paiva TO, Geiger CJ, Baker AE, O'Toole GA, Dufrêne YF. Atomic force microscopy analysis of Pel polysaccharide- and type IV pili-mediated adhesion of Pseudomonas aeruginosa PA14 to an abiotic surface. NANOSCALE 2024. [PMID: 38832761 DOI: 10.1039/d4nr01415d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2024]
Abstract
Type IV pili (TFP) contribute to the ability of microbes such as Pseudomonas aeruginosa to engage with and move across surfaces. We reported previously that P. aeruginosa TFP generate retractive forces of ∼30 pN and provided indirect evidence that TFP-mediated surface attachment was enhanced in the presence of the Pel polysaccharide. Here, we use different mutants defective in flagellar, Pel production or TFP production - alone or in combination - to decipher the relative contribution of these biofilm-promoting factors for P. aeruginosa adhesion. By means of atomic force microscopy (AFM), we show that mutating the flagellum (ΔflgK mutant) results in an increase in Pel polysaccharide production, but this increase in Pel does not result in an increase in surface adhesive properties compared to those previously described for the WT strain. By blocking Pel production in the ΔflgK mutant (ΔflgKΔpel), we directly show that TFP play a major role in the adhesion of the bacteria to hydrophobic AFM tips, but that the adhesion force is only slightly impaired by the absence of Pel. Inversely, performing single-cell force spectroscopy measurements with the mutant lacking TFP (ΔflgKΔpilA) reveals that the Pel can modulate the attachment of the bacteria to a hydrophobic substrate in a time-dependent manner. Finally, little adhesion was detected for the ΔflgKΔpilAΔpelA triple mutant, suggesting that both TFP and Pel polysaccharide make a substantial contribution to bacteria-substratum interaction events. Altogether, our data allow us to decipher the relative contribution of Pel and TFP in the early attachment by P. aeruginosa.
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Affiliation(s)
- Audrey Beaussart
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, L7.07.07, B-1348 Louvain-la-Neuve, Belgium.
| | - Telmo O Paiva
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, L7.07.07, B-1348 Louvain-la-Neuve, Belgium.
| | - Christopher J Geiger
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, USA.
| | - Amy E Baker
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, USA.
| | - George A O'Toole
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, USA.
| | - Yves F Dufrêne
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, L7.07.07, B-1348 Louvain-la-Neuve, Belgium.
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2
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Kunzler M, Schlechter RO, Schreiber L, Remus-Emsermann MNP. Hitching a Ride in the Phyllosphere: Surfactant Production of Pseudomonas spp. Causes Co-swarming of Pantoea eucalypti 299R. MICROBIAL ECOLOGY 2024; 87:62. [PMID: 38683223 PMCID: PMC11058625 DOI: 10.1007/s00248-024-02381-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Accepted: 04/17/2024] [Indexed: 05/01/2024]
Abstract
Here, we demonstrate the beneficial effect of surfactant-producing pseudomonads on Pantoea eucalypti 299R. We conducted a series of experiments in environments of increasing complexity. P. eucalypti 299R (Pe299R), and Pseudomonas sp. FF1 (Pff1) or Pe299R and surfactant-production deficient Pseudomonas sp. FF1::ΔviscB (Pff1ΔviscB) were co-inoculated in broth, on swarming agar plates, and on plants. In broth, there were no differences in the growth dynamics of Pe299R when growing in the presence of Pff1 or Pff1ΔviscB. By contrast, on swarming agar plates, Pe299R was able to co-swarm with Pff1 which led to a significant increase in Pe299R biomass compared to Pe299R growing with Pff1ΔviscB or in monoculture. Finally in planta, and using the single-cell bioreporter for reproductive success (CUSPER), we found a temporally distinct beneficial effect of Pff1 on co-inoculated Pe299R subpopulations that did not occur in the presence of Pff1ΔviscB. We tested three additional surfactant-producing pseudomonads and their respective surfactant knockout mutants on PE299R on swarming agar showing similar results. This led us to propose a model for the positive effect of surfactant production during leaf colonization. Our results indicate that co-motility might be common during leaf colonization and adds yet another facet to the already manyfold roles of surfactants.
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Affiliation(s)
- Michael Kunzler
- Institute for Biology - Microbiology, Freie Universität Berlin, Königin-Luise Straße 12-16, 14195, Berlin, Germany
| | - Rudolf O Schlechter
- Institute for Biology - Microbiology, Freie Universität Berlin, Königin-Luise Straße 12-16, 14195, Berlin, Germany
| | - Lukas Schreiber
- Institute for Cellular and Molecular Botany, Bonn University, Kirschallee 1-3, 53115, Bonn, Germany
| | - Mitja N P Remus-Emsermann
- Institute for Biology - Microbiology, Freie Universität Berlin, Königin-Luise Straße 12-16, 14195, Berlin, Germany.
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3
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Meng J, Zan F, Liu Z, Zhang Y, Qin C, Hao L, Wang Z, Wang L, Liu D, Liang S, Li H, Li H, Ding S. Genomics Analysis Reveals the Potential Biocontrol Mechanism of Pseudomonas aeruginosa QY43 against Fusarium pseudograminearum. J Fungi (Basel) 2024; 10:298. [PMID: 38667969 PMCID: PMC11050789 DOI: 10.3390/jof10040298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 04/11/2024] [Accepted: 04/19/2024] [Indexed: 04/28/2024] Open
Abstract
Fusarium crown rot (FCR) in wheat is a prevalent soil-borne disease worldwide and poses a significant threat to the production of wheat (Triticum aestivum) in China, with F. pseudograminearum being the dominant pathogen. Currently, there is a shortage of biocontrol resources to control FCR induced by F. pseudograminearum, along with biocontrol mechanisms. In this study, we have identified 37 strains of biocontrol bacteria displaying antagonistic effects against F. pseudograminearum from over 8000 single colonies isolated from soil samples with a high incidence of FCR. Among them, QY43 exhibited remarkable efficacy in controlling FCR. Further analysis identified the isolate QY43 as Pseudomonas aeruginosa, based on its colony morphology and molecular biology. In vitro, QY43 significantly inhibited the growth, conidial germination, and the pathogenicity of F. pseudograminearum. In addition, QY43 exhibited a broad spectrum of antagonistic activities against several plant pathogens. The genomics analysis revealed that there are genes encoding potential biocontrol factors in the genome of QY43. The experimental results confirmed that QY43 secretes biocontrol factor siderophores and pyocyanin. In summary, QY43 exhibits a broad spectrum of antagonistic activities and the capacity to produce diverse biocontrol factors, thereby showing substantial potential for biocontrol applications to plant disease.
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Affiliation(s)
- Jiaxing Meng
- College of Plant Protection, Henan Agricultural University, Zhengzhou 450046, China; (J.M.); (F.Z.); (Z.L.); (Y.Z.); (C.Q.); (L.H.); (Z.W.); (L.W.); (H.L.)
| | - Feifei Zan
- College of Plant Protection, Henan Agricultural University, Zhengzhou 450046, China; (J.M.); (F.Z.); (Z.L.); (Y.Z.); (C.Q.); (L.H.); (Z.W.); (L.W.); (H.L.)
| | - Zheran Liu
- College of Plant Protection, Henan Agricultural University, Zhengzhou 450046, China; (J.M.); (F.Z.); (Z.L.); (Y.Z.); (C.Q.); (L.H.); (Z.W.); (L.W.); (H.L.)
| | - Yuan Zhang
- College of Plant Protection, Henan Agricultural University, Zhengzhou 450046, China; (J.M.); (F.Z.); (Z.L.); (Y.Z.); (C.Q.); (L.H.); (Z.W.); (L.W.); (H.L.)
| | - Cancan Qin
- College of Plant Protection, Henan Agricultural University, Zhengzhou 450046, China; (J.M.); (F.Z.); (Z.L.); (Y.Z.); (C.Q.); (L.H.); (Z.W.); (L.W.); (H.L.)
| | - Lingjun Hao
- College of Plant Protection, Henan Agricultural University, Zhengzhou 450046, China; (J.M.); (F.Z.); (Z.L.); (Y.Z.); (C.Q.); (L.H.); (Z.W.); (L.W.); (H.L.)
| | - Zhifang Wang
- College of Plant Protection, Henan Agricultural University, Zhengzhou 450046, China; (J.M.); (F.Z.); (Z.L.); (Y.Z.); (C.Q.); (L.H.); (Z.W.); (L.W.); (H.L.)
| | - Limin Wang
- College of Plant Protection, Henan Agricultural University, Zhengzhou 450046, China; (J.M.); (F.Z.); (Z.L.); (Y.Z.); (C.Q.); (L.H.); (Z.W.); (L.W.); (H.L.)
| | - Dongmei Liu
- Institute of Quality Standards and Testing Technology for Agro-Products, Henan Academy of Agricultural Sciences, Zhengzhou 450002, China;
| | - Shen Liang
- Horticulture Research Institute, Henan Academy of Agricultural Sciences, Zhengzhou 450002, China;
| | - Honglian Li
- College of Plant Protection, Henan Agricultural University, Zhengzhou 450046, China; (J.M.); (F.Z.); (Z.L.); (Y.Z.); (C.Q.); (L.H.); (Z.W.); (L.W.); (H.L.)
- National Key Laboratory of Wheat and Maize Crop Science, Zhengzhou 450046, China
| | - Haiyang Li
- College of Plant Protection, Henan Agricultural University, Zhengzhou 450046, China; (J.M.); (F.Z.); (Z.L.); (Y.Z.); (C.Q.); (L.H.); (Z.W.); (L.W.); (H.L.)
| | - Shengli Ding
- College of Plant Protection, Henan Agricultural University, Zhengzhou 450046, China; (J.M.); (F.Z.); (Z.L.); (Y.Z.); (C.Q.); (L.H.); (Z.W.); (L.W.); (H.L.)
- National Key Laboratory of Wheat and Maize Crop Science, Zhengzhou 450046, China
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4
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Weaver AA, Jia J, Cutri AR, Madukoma CS, Vaerewyck CM, Bohn PW, Shrout JD. Alkyl quinolones mediate heterogeneous colony biofilm architecture that improves community-level survival. J Bacteriol 2024; 206:e0009524. [PMID: 38564677 PMCID: PMC11025328 DOI: 10.1128/jb.00095-24] [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: 03/05/2024] [Accepted: 03/11/2024] [Indexed: 04/04/2024] Open
Abstract
Bacterial communities exhibit complex self-organization that contributes to their survival. To better understand the molecules that contribute to transforming a small number of cells into a heterogeneous surface biofilm community, we studied acellular aggregates, structures seen by light microscopy in Pseudomonas aeruginosa colony biofilms using light microscopy and chemical imaging. These structures differ from cellular aggregates, cohesive clusters of cells important for biofilm formation, in that they are visually distinct from cells using light microscopy and are reliant on metabolites for assembly. To investigate how these structures benefit a biofilm community we characterized three recurrent types of acellular aggregates with distinct geometries that were each abundant in specific areas of these biofilms. Alkyl quinolones (AQs) were essential for the formation of all aggregate types with AQ signatures outside the aggregates below the limit of detection. These acellular aggregates spatially sequester AQs and differentiate the biofilm space. However, the three types of aggregates showed differing properties in their size, associated cell death, and lipid content. The largest aggregate type co-localized with spatially confined cell death that was not mediated by Pf4 bacteriophage. Biofilms lacking AQs were absent of localized cell death but exhibited increased, homogeneously distributed cell death. Thus, these AQ-rich aggregates regulate metabolite accessibility, differentiate regions of the biofilm, and promote survival in biofilms.IMPORTANCEPseudomonas aeruginosa is an opportunistic pathogen with the ability to cause infection in the immune-compromised. It is well established that P. aeruginosa biofilms exhibit resilience that includes decreased susceptibility to antimicrobial treatment. This work examines the self-assembled heterogeneity in biofilm communities studying acellular aggregates, regions of condensed matter requiring alkyl quinolones (AQs). AQs are important to both virulence and biofilm formation. Aggregate structures described here spatially regulate the accessibility of these AQs, differentiate regions of the biofilm community, and despite their association with autolysis, correlate with improved P. aeruginosa colony biofilm survival.
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Affiliation(s)
- Abigail A. Weaver
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Jin Jia
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, USA
| | - Allison R. Cutri
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, USA
| | - Chinedu S. Madukoma
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Catherine M. Vaerewyck
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Paul W. Bohn
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, USA
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana, USA
| | - Joshua D. Shrout
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana, USA
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
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5
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Kłosowska-Chomiczewska IE, Macierzanka A, Parchem K, Miłosz P, Bladowska S, Płaczkowska I, Hewelt-Belka W, Jungnickel C. Microbe cultivation guidelines to optimize rhamnolipid applications. Sci Rep 2024; 14:8362. [PMID: 38600115 PMCID: PMC11006924 DOI: 10.1038/s41598-024-59021-7] [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: 12/18/2023] [Accepted: 04/05/2024] [Indexed: 04/12/2024] Open
Abstract
In the growing landscape of interest in natural surfactants, selecting the appropriate one for specific applications remains challenging. The extensive, yet often unsystematized, knowledge of microbial surfactants, predominantly represented by rhamnolipids (RLs), typically does not translate beyond the conditions presented in scientific publications. This limitation stems from the numerous variables and their interdependencies that characterize microbial surfactant production. We hypothesized that a computational recipe for biosynthesizing RLs with targeted applicational properties could be developed from existing literature and experimental data. We amassed literature data on RL biosynthesis and micellar solubilization and augmented it with our experimental results on the solubilization of triglycerides (TGs), a topic underrepresented in current literature. Utilizing this data, we constructed mathematical models that can predict RL characteristics and solubilization efficiency, represented as logPRL = f(carbon and nitrogen source, parameters of biosynthesis) and logMSR = f(solubilizate, rhamnolipid (e.g. logPRL), parameters of solubilization), respectively. The models, characterized by robust R2 values of respectively 0.581-0.997 and 0.804, enabled the ranking of descriptors based on their significance and impact-positive or negative-on the predicted values. These models have been translated into ready-to-use calculators, tools designed to streamline the selection process for identifying a biosurfactant optimally suited for intended applications.
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Affiliation(s)
- Ilona E Kłosowska-Chomiczewska
- Department of Colloid and Lipid Science, Faculty of Chemistry, Gdańsk University of Technology, 11/12 G. Narutowicza St., 80-233, Gdańsk, Poland.
| | - Adam Macierzanka
- Department of Colloid and Lipid Science, Faculty of Chemistry, Gdańsk University of Technology, 11/12 G. Narutowicza St., 80-233, Gdańsk, Poland
| | - Karol Parchem
- Department of Chemistry, Technology and Biotechnology of Food, Faculty of Chemistry, Gdańsk University of Technology, 11/12 G. Narutowicza St., 80-233, Gdańsk, Poland
| | - Pamela Miłosz
- Department of Colloid and Lipid Science, Faculty of Chemistry, Gdańsk University of Technology, 11/12 G. Narutowicza St., 80-233, Gdańsk, Poland
| | - Sonia Bladowska
- Department of Colloid and Lipid Science, Faculty of Chemistry, Gdańsk University of Technology, 11/12 G. Narutowicza St., 80-233, Gdańsk, Poland
| | - Iga Płaczkowska
- Department of Colloid and Lipid Science, Faculty of Chemistry, Gdańsk University of Technology, 11/12 G. Narutowicza St., 80-233, Gdańsk, Poland
| | - Weronika Hewelt-Belka
- Department of Analytical Chemistry, Faculty of Chemistry, Gdańsk University of Technology, 11/12 G. Narutowicza St., 80-233, Gdańsk, Poland
| | - Christian Jungnickel
- Department of Colloid and Lipid Science, Faculty of Chemistry, Gdańsk University of Technology, 11/12 G. Narutowicza St., 80-233, Gdańsk, Poland
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6
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Cheng T, Cheang QW, Xu L, Sheng S, Li Z, Shi Y, Zhang H, Pang LM, Liu DX, Yang L, Liang ZX, Wang J. A PilZ domain protein interacts with the transcriptional regulator HinK to regulate type VI secretion system in Pseudomonas aeruginosa. J Biol Chem 2024; 300:105741. [PMID: 38340793 PMCID: PMC10912698 DOI: 10.1016/j.jbc.2024.105741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 01/29/2024] [Accepted: 02/04/2024] [Indexed: 02/12/2024] Open
Abstract
Type VI secretion systems (T6SS) are bacterial macromolecular complexes that secrete effectors into target cells or the extracellular environment, leading to the demise of adjacent cells and providing a survival advantage. Although studies have shown that the T6SS in Pseudomonas aeruginosa is regulated by the Quorum Sensing system and second messenger c-di-GMP, the underlying molecular mechanism remains largely unknown. In this study, we discovered that the c-di-GMP-binding adaptor protein PA0012 has a repressive effect on the expression of the T6SS HSI-I genes in P. aeruginosa PAO1. To probe the mechanism by which PA0012 (renamed TssZ, Type Six Secretion System -associated PilZ protein) regulates the expression of HSI-I genes, we conducted yeast two-hybrid screening and identified HinK, a LasR-type transcriptional regulator, as the binding partner of TssZ. The protein-protein interaction between HinK and TssZ was confirmed through co-immunoprecipitation assays. Further analysis suggested that the HinK-TssZ interaction was weakened at high c-di-GMP concentrations, contrary to the current paradigm wherein c-di-GMP enhances the interaction between PilZ proteins and their partners. Electrophoretic mobility shift assays revealed that the non-c-di-GMP-binding mutant TssZR5A/R9A interacts directly with HinK and prevents it from binding to the promoter of the quorum-sensing regulator pqsR. The functional connection between TssZ and HinK is further supported by observations that TssZ and HinK impact the swarming motility, pyocyanin production, and T6SS-mediated bacterial killing activity of P. aeruginosa in a PqsR-dependent manner. Together, these results unveil a novel regulatory mechanism wherein TssZ functions as an inhibitor that interacts with HinK to control gene expression.
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Affiliation(s)
- Tianfang Cheng
- Integrative Microbiology Research Centre, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
| | - Qing Wei Cheang
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Linghui Xu
- Integrative Microbiology Research Centre, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
| | - Shuo Sheng
- Integrative Microbiology Research Centre, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China; Key Laboratory of Basic Pharmacology of the Ministry of Education, Joint International Research Laboratory of Ethnomedicine of the Ministry of Education and Key Laboratory of Basic Pharmacology of Guizhou Province, Zunyi Medical University, Zunyi, Guizhou, China
| | - Zhaoting Li
- Integrative Microbiology Research Centre, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
| | - Yu Shi
- Integrative Microbiology Research Centre, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
| | - Huiyan Zhang
- Integrative Microbiology Research Centre, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
| | - Li Mei Pang
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Ding Xiang Liu
- Integrative Microbiology Research Centre, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
| | - Liang Yang
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Zhao-Xun Liang
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.
| | - Junxia Wang
- Integrative Microbiology Research Centre, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China.
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7
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Weaver AA, Parmar D, Junker EA, Sweedler JV, Shrout JD. Differential Spreading of Rhamnolipid Congeners from Pseudomonas aeruginosa. ACS APPLIED BIO MATERIALS 2023; 6:4914-4921. [PMID: 37878954 PMCID: PMC11107424 DOI: 10.1021/acsabm.3c00641] [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] [Indexed: 10/27/2023]
Abstract
Rhamnolipids are surfactants produced by many Pseudomonad bacteria, including the species Pseudomonas aeruginosa. These rhamnolipids are known to aid and enable numerous phenotypic traits that improve the survival of the bacteria that make them. These surfactants are also important for industrial products ranging from pharmaceuticals to cleaning supplies to cosmetics, to name a few. Rhamnolipids have structural diversity that leads to an array of congeners; however, little is known about the localization and distribution of these congeners in two-dimensional space. Differential distribution of congeners can reduce the uniformity of applications in industrial settings and create heterogeneity within biological communities. We examined the distribution patterns of combinations of rhamnolipids in commercially available mixtures, cell-free spent media, and colony biofilms using mass spectrometry. We found that even in the absence of cells, congeners exhibit different distribution patterns, leading to different rhamnolipid congener distributions on a surface. Congeners with shorter fatty acid chains were more centrally located, while longer chains were more heterogeneous and distally located. We found that congeners with similar structures can distribute differently. Within developing colony biofilms, we found rhamnolipid distribution patterns differed from cell-free environments, lacking simple trends noted in cell-free environments. Most strikingly, we found the distribution patterns of individual congeners in the colony biofilms to be diverse. We note that the congener distribution is far from homogeneous but composed of numerous local microenvironments of varied rhamnolipid congener composition.
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Affiliation(s)
- Abigail A. Weaver
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Dharmeshkumar Parmar
- Department of Chemistry and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Ella A. Junker
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Jonathan V. Sweedler
- Department of Chemistry and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Joshua D. Shrout
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana 46556, United States
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana 46556, United States
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8
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Cutri A, Shrout JD, Bohn PW. Metabolic and Oxidative Stress Effects on the Spectroelectrochemical Behavior of Single Pseudomonas aeruginosa Cells. CHEMICAL & BIOMEDICAL IMAGING 2023; 1:659-666. [PMID: 37886305 PMCID: PMC10598847 DOI: 10.1021/cbmi.3c00083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 09/15/2023] [Accepted: 09/25/2023] [Indexed: 10/28/2023]
Abstract
Pseudomonas aeruginosa is an opportunistic human pathogen capable of causing a wide range of diseases in immunocompromised patients. In order to better understand P. aeruginosa behavior and virulence and to advance drug therapies to combat infection, it would be beneficial to understand how P. aeruginosa cells survive stressful conditions, especially environmental stressors. Here, we report on a strategy that measures potential-dependent fluorescence of individual P. aeruginosa cells, as a sentinel, for cellular response to starvation, hunger, and oxidative stress. This is accomplished using a micropore electrode array capable of trapping large numbers of isolated, vertically oriented cells at well-defined spatial positions in order to study large arrays of single cells in parallel. We find that conditions promoting either starvation or oxidative stress produce discernible changes in the fluorescence response, demonstrated by an increase in the prevalence of fluorescence transients, one of three canonical spectroelectrochemical behaviors exhibited by single P. aeruginosa cells. In contrast, more modest nutrient limitations have little to no effect on the spectroelectrochemical response when compared to healthy cells in the stationary phase. These findings demonstrate the capabilities of micropore electrode arrays for studying the behavior of single microbial cells under conditions where the intercellular spacing, orientation, and chemical environment of the cells are controlled. Realizing single-cell studies under such well-defined conditions makes it possible to study fundamental stress responses with unprecedented control.
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Affiliation(s)
- Allison
R. Cutri
- Department
of Chemistry and Biochemistry, University
of Notre Dame, Notre
Dame, Indiana 46556, United States
| | - Joshua D. Shrout
- Department
of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana 46556, United States
- Department
of Biological Sciences, University of Notre
Dame, Notre Dame, Indiana 46556, United
States
| | - Paul W. Bohn
- Department
of Chemistry and Biochemistry, University
of Notre Dame, Notre
Dame, Indiana 46556, United States
- Department
of Chemical and Biomolecular Engineering, University of Notre Dame, Notre
Dame, Indiana 46556, United States
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9
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Bru JL, Kasallis SJ, Chang R, Zhuo Q, Nguyen J, Pham P, Warren E, Whiteson K, Høyland-Kroghsbo NM, Limoli DH, Siryaporn A. The great divide: rhamnolipids mediate separation between P. aeruginosa and S. aureus. Front Cell Infect Microbiol 2023; 13:1245874. [PMID: 37780859 PMCID: PMC10540625 DOI: 10.3389/fcimb.2023.1245874] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 08/23/2023] [Indexed: 10/03/2023] Open
Abstract
The interactions between bacterial species during infection can have significant impacts on pathogenesis. Pseudomonas aeruginosa and Staphylococcus aureus are opportunistic bacterial pathogens that can co-infect hosts and cause serious illness. The factors that dictate whether one species outcompetes the other or whether the two species coexist are not fully understood. We investigated the role of surfactants in the interactions between these two species on a surface that enables P. aeruginosa to swarm. We found that P. aeruginosa swarms are repelled by colonies of clinical S. aureus isolates, creating physical separation between the two strains. This effect was abolished in mutants of S. aureus that were defective in the production of phenol-soluble modulins (PSMs), which form amyloid fibrils around wild-type S. aureus colonies. We investigated the mechanism that establishes physical separation between the two species using Imaging of Reflected Illuminated Structures (IRIS), which is a non-invasive imaging method that tracks the flow of surfactants produced by P. aeruginosa. We found that PSMs produced by S. aureus deflected the surfactant flow, which in turn, altered the direction of P. aeruginosa swarms. These findings show that rhamnolipids mediate physical separation between P. aeruginosa and S. aureus, which could facilitate coexistence between these species. Additionally, we found that a number of molecules repelled P. aeruginosa swarms, consistent with a surfactant deflection mechanism. These include Bacillus subtilis surfactant, the fatty acids oleic acid and linoleic acid, and the synthetic lubricant polydimethylsiloxane. Lung surfactant repelled P. aeruginosa swarms and inhibited swarm expansion altogether at higher concentration. Our results suggest that surfactant interactions could have major impacts on bacteria-bacteria and bacteria-host relationships. In addition, our findings uncover a mechanism responsible for P. aeruginosa swarm development that does not rely solely on sensing but instead is based on the flow of surfactant.
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Affiliation(s)
- Jean-Louis Bru
- Department of Molecular Biology & Biochemistry, University of California, Irvine, Irvine, CA, United States
| | - Summer J. Kasallis
- Department of Molecular Biology & Biochemistry, University of California, Irvine, Irvine, CA, United States
- Department of Physics & Astronomy, University of California, Irvine, Irvine, CA, United States
| | - Rendell Chang
- School of Biological Sciences, University of California, Irvine, Irvine, CA, United States
| | - Quantum Zhuo
- Department of Physics & Astronomy, University of California, Irvine, Irvine, CA, United States
| | - Jacqueline Nguyen
- School of Biological Sciences, University of California, Irvine, Irvine, CA, United States
| | - Phillip Pham
- Department of Molecular Biology & Biochemistry, University of California, Irvine, Irvine, CA, United States
| | - Elizabeth Warren
- Department of Microbiology and Immunology, University of Iowa, Iowa City, IA, United States
| | - Katrine Whiteson
- Department of Molecular Biology & Biochemistry, University of California, Irvine, Irvine, CA, United States
| | | | - Dominique H. Limoli
- Department of Microbiology and Immunology, University of Iowa, Iowa City, IA, United States
| | - Albert Siryaporn
- Department of Molecular Biology & Biochemistry, University of California, Irvine, Irvine, CA, United States
- Department of Physics & Astronomy, University of California, Irvine, Irvine, CA, United States
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10
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Bru JL, Kasallis SJ, Zhuo Q, Høyland-Kroghsbo NM, Siryaporn A. Swarming of P. aeruginosa: Through the lens of biophysics. BIOPHYSICS REVIEWS 2023; 4:031305. [PMID: 37781002 PMCID: PMC10540860 DOI: 10.1063/5.0128140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 08/29/2023] [Indexed: 10/03/2023]
Abstract
Swarming is a collective flagella-dependent movement of bacteria across a surface that is observed across many species of bacteria. Due to the prevalence and diversity of this motility modality, multiple models of swarming have been proposed, but a consensus on a general mechanism for swarming is still lacking. Here, we focus on swarming by Pseudomonas aeruginosa due to the abundance of experimental data and multiple models for this species, including interpretations that are rooted in biology and biophysics. In this review, we address three outstanding questions about P. aeruginosa swarming: what drives the outward expansion of a swarm, what causes the formation of dendritic patterns (tendrils), and what are the roles of flagella? We review models that propose biologically active mechanisms including surfactant sensing as well as fluid mechanics-based models that consider swarms as thin liquid films. Finally, we reconcile recent observations of P. aeruginosa swarms with early definitions of swarming. This analysis suggests that mechanisms associated with sliding motility have a critical role in P. aeruginosa swarm formation.
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Affiliation(s)
- Jean-Louis Bru
- Department of Molecular Biology and Biochemistry, University of California Irvine, Irvine, California 92697, USA
| | - Summer J. Kasallis
- Department of Physics and Astronomy, University of California Irvine, Irvine, California 92697, USA
| | - Quantum Zhuo
- Department of Physics and Astronomy, University of California Irvine, Irvine, California 92697, USA
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11
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Kasallis S, Bru JL, Chang R, Zhuo Q, Siryaporn A. Understanding how bacterial collectives organize on surfaces by tracking surfactant flow. CURRENT OPINION IN SOLID STATE & MATERIALS SCIENCE 2023; 27:101080. [PMID: 37427092 PMCID: PMC10327653 DOI: 10.1016/j.cossms.2023.101080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
Swarming is a collective bacterial behavior in which a dense population of bacterial cells moves over a porous surface, resulting in the expansion of the population. This collective behavior can guide bacteria away from potential stressors such as antibiotics and bacterial viruses. However, the mechanisms responsible for the organization of swarms are not understood. Here, we briefly review models that are based on bacterial sensing and fluid mechanics that are proposed to guide swarming in the pathogenic bacterium Pseudomonas aeruginosa. To provide further insight into the role of fluid mechanics in P. aeruginosa swarms, we track the movement of tendrils and the flow of surfactant using a novel technique that we have developed, Imaging of Reflected Illuminated Structures (IRIS). Our measurements show that tendrils and surfactants form distinct layers that grow in lockstep with each other. The results raise new questions about existing swarming models and the possibility that the flow of surfactants impacts tendril development. These findings emphasize that swarm organization involves an interplay between biological processes and fluid mechanics.
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Affiliation(s)
- Summer Kasallis
- Department of Physics & Astronomy, University of California Irvine, Irvine, CA 92697, USA
| | - Jean-Louis Bru
- Department of Molecular Biology & Biochemistry, University of California Irvine, Irvine, CA 92697, USA
| | - Rendell Chang
- Department of Molecular Biology & Biochemistry, University of California Irvine, Irvine, CA 92697, USA
| | - Quantum Zhuo
- Department of Physics & Astronomy, University of California Irvine, Irvine, CA 92697, USA
| | - Albert Siryaporn
- Department of Physics & Astronomy, University of California Irvine, Irvine, CA 92697, USA
- Department of Molecular Biology & Biochemistry, University of California Irvine, Irvine, CA 92697, USA
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12
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Deforet M. Long-range alteration of the physical environment mediates cooperation between Pseudomonas aeruginosa swarming colonies. Environ Microbiol 2023. [PMID: 36964975 DOI: 10.1111/1462-2920.16373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 03/15/2023] [Indexed: 03/27/2023]
Abstract
Pseudomonas aeruginosa makes and secretes massive amounts of rhamnolipid surfactants that enable swarming motility over biogel surfaces. But how these rhamnolipids interact with biogels to assist swarming remains unclear. Here, I use a combination of optical techniques across scales and genetically engineered strains to demonstrate that rhamnolipids can induce agar gel swelling over distances >10,000× the body size of an individual cell. The swelling front is on the micrometric scale and is easily visible using shadowgraphy. Rhamnolipid transport is not restricted to the surface of the gel but occurs through the whole thickness of the plate and, consequently, the spreading dynamics depend on the local thickness. Surprisingly, rhamnolipids can cross the whole gel and induce swelling on the opposite side of a two-face Petri dish. The swelling front delimits an area where the mechanical properties of the surface properties are modified: water wets the surface more easily, which increases the motility of individual bacteria and enables collective motility. A genetically engineered mutant unable to secrete rhamnolipids (ΔrhlA), and therefore unable to swarm, is rescued from afar with rhamnolipids produced by a remote colony. These results exemplify the remarkable capacity of bacteria to change the physical environment around them and its ecological consequences.
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Affiliation(s)
- Maxime Deforet
- Sorbonne Université, Centre National de la Recherche Scientifique, Laboratoire Jean Perrin, LJP, Paris, 75005, France
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13
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Bacterial Motility and Its Role in Skin and Wound Infections. Int J Mol Sci 2023; 24:ijms24021707. [PMID: 36675220 PMCID: PMC9864740 DOI: 10.3390/ijms24021707] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Revised: 01/06/2023] [Accepted: 01/13/2023] [Indexed: 01/19/2023] Open
Abstract
Skin and wound infections are serious medical problems, and the diversity of bacteria makes such infections difficult to treat. Bacteria possess many virulence factors, among which motility plays a key role in skin infections. This feature allows for movement over the skin surface and relocation into the wound. The aim of this paper is to review the type of bacterial movement and to indicate the underlying mechanisms than can serve as a target for developing or modifying antibacterial therapies applied in wound infection treatment. Five types of bacterial movement are distinguished: appendage-dependent (swimming, swarming, and twitching) and appendage-independent (gliding and sliding). All of them allow bacteria to relocate and aid bacteria during infection. Swimming motility allows bacteria to spread from 'persister cells' in biofilm microcolonies and colonise other tissues. Twitching motility enables bacteria to press through the tissues during infection, whereas sliding motility allows cocci (defined as non-motile) to migrate over surfaces. Bacteria during swarming display greater resistance to antimicrobials. Molecular motors generating the focal adhesion complexes in the bacterial cell leaflet generate a 'wave', which pushes bacterial cells lacking appendages, thereby enabling movement. Here, we present the five main types of bacterial motility, their molecular mechanisms, and examples of bacteria that utilise them. Bacterial migration mechanisms can be considered not only as a virulence factor but also as a target for antibacterial therapy.
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14
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Jia J, Parmar D, Ellis JF, Cao T, Cutri AR, Shrout JD, Sweedler JV, Bohn PW. Effect of Micro-Patterned Mucin on Quinolone and Rhamnolipid Profiles of Mucoid Pseudomonas aeruginosa under Antibiotic Stress. ACS Infect Dis 2023; 9:150-161. [PMID: 36538577 PMCID: PMC10116410 DOI: 10.1021/acsinfecdis.2c00519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Pseudomonas aeruginosa (P. aeruginosa) is commonly implicated in hospital-acquired infections where its capacity to form biofilms on a variety of surfaces and the resulting enhanced antibiotic resistance seriously limit treatment choices. Because surface attachment sensitizes P. aeruginosa to quorum sensing (QS) and induces virulence through both chemical and mechanical cues, we investigate the effect of surface properties through spatially patterned mucin, combined with sub-inhibitory concentrations of tobramycin on QS and virulence factors in both mucoid and non-mucoid P. aeruginosa strains using multi-modal chemical imaging combining confocal Raman microscopy and matrix-assisted laser desorption/ionization-mass spectrometry. Samples comprise surface-adherent static biofilms at a solid-water interface, supernatant liquid, and pellicle biofilms at an air-water interface at various time points. Although the presence of a sub-inhibitory concentration of tobramycin in the supernatant retards growth and development of static biofilms independent of strain and surface mucin patterning, we observe clear differences in the behavior of mucoid and non-mucoid strains. Quinolone signals in a non-mucoid strain are induced earlier and are influenced by mucin surface patterning to a degree not exhibited in the mucoid strain. Additionally, phenazine virulence factors, such as pyocyanin, are observed in the pellicle biofilms of both mucoid and non-mucoid strains but are not detected in the static biofilms from either strain, highlighting the differences in stress response between pellicle and static biofilms. Differences between mucoid and non-mucoid strains are consistent with their strain-specific phenology, in which the mucoid strain develops highly protected biofilms.
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Affiliation(s)
- Jin Jia
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Dharmeshkumar Parmar
- Department of Chemistry and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Joanna F Ellis
- Department of Chemistry and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Tianyuan Cao
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Allison R Cutri
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Joshua D Shrout
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana 46556, United States.,Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Jonathan V Sweedler
- Department of Chemistry and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Paul W Bohn
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States.,Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556, United States
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15
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Dubern JF, Romero M, Mai-Prochnow A, Messina M, Trampari E, Gijzel HNV, Chan KG, Carabelli AM, Barraud N, Lazenby J, Chen Y, Robertson S, Malone JG, Williams P, Heeb S, Cámara M. ToxR is a c-di-GMP binding protein that modulates surface-associated behaviour in Pseudomonas aeruginosa. NPJ Biofilms Microbiomes 2022; 8:64. [PMID: 35982053 PMCID: PMC9388670 DOI: 10.1038/s41522-022-00325-9] [Citation(s) in RCA: 4] [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: 05/16/2022] [Accepted: 07/26/2022] [Indexed: 11/09/2022] Open
Abstract
Pseudomonas aeruginosa uses multiple protein regulators that work in tandem to control the production of a wide range of virulence factors and facilitate rapid adaptation to diverse environmental conditions. In this opportunistic pathogen, ToxR was known to positively regulate the production of the major virulence factor exotoxin A and now, through analysis of genetic changes between two sublines of P. aeruginosa PAO1 and functional complementation of swarming, we have identified a previously unknown role of ToxR in surface-associated motility in P. aeruginosa. Further analysis revealed that ToxR had an impact on swarming motility by regulating the Rhl quorum sensing system and subsequent production of rhamnolipid surfactants. Additionally, ToxR was found to tightly bind cyclic diguanylate (c-di-GMP) and negatively affect traits controlled by this second messenger including reducing biofilm formation and the expression of Psl and Pel exopolysaccharides, necessary for attachment and sessile communities matrix scaffolding, in P. aeruginosa. Moreover, a link between the post-transcriptional regulator RsmA and toxR expression via the alternative sigma factor PvdS, induced under iron-limiting conditions, is established. This study reveals the importance of ToxR in a sophisticated regulation of free-living and biofilm-associated lifestyles, appropriate for establishing acute or chronic P. aeruginosa infections.
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Affiliation(s)
- Jean-Frédéric Dubern
- National Biofilms Innovation Centre, Biodiscovery Institute and School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Manuel Romero
- National Biofilms Innovation Centre, Biodiscovery Institute and School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Anne Mai-Prochnow
- National Biofilms Innovation Centre, Biodiscovery Institute and School of Life Sciences, University of Nottingham, Nottingham, UK
- School of Chemical and Biomolecular Engineering, University of Sydney, Sydney, Australia
| | - Marco Messina
- National Biofilms Innovation Centre, Biodiscovery Institute and School of Life Sciences, University of Nottingham, Nottingham, UK
- Department of Science, University Roma Tre, Rome, Italy
| | - Eleftheria Trampari
- Department of Molecular Microbiology, John Innes Centre, Norwich, UK
- Quadram Institute Bioscience, Norwich Research Park, Norwich, UK
| | - Hardeep Naghra-van Gijzel
- National Biofilms Innovation Centre, Biodiscovery Institute and School of Life Sciences, University of Nottingham, Nottingham, UK
- Genomic Sciences, GlaxoSmithKline Research and Development, Stevenage, UK
| | - Kok-Gan Chan
- Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia
- International Genome Centre, Jiangsu University, Zhenjiang, China
| | - Alessandro M Carabelli
- School of Pharmacy, Boots Science Building, University of Nottingham, Nottingham, UK
- Department of Medicine, University of Cambridge, Cambridge, UK
| | - Nicolas Barraud
- Centre for Marine Bio-Innovation, School of Biotechnology and Biomolecular Science, University of New South Wales, Sydney, Australia
- Genetics of Biofilms Unit, Institut Pasteur, Paris, France
| | - James Lazenby
- National Biofilms Innovation Centre, Biodiscovery Institute and School of Life Sciences, University of Nottingham, Nottingham, UK
- Quadram Institute Bioscience, Norwich Research Park, Norwich, UK
| | - Ye Chen
- National Biofilms Innovation Centre, Biodiscovery Institute and School of Life Sciences, University of Nottingham, Nottingham, UK
- Q Squared Solutions, Crystal Plaza, Pudong, Shanghai, China
| | - Shaun Robertson
- National Biofilms Innovation Centre, Biodiscovery Institute and School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Jacob G Malone
- Department of Molecular Microbiology, John Innes Centre, Norwich, UK
- School of Biological Sciences, University of East Anglia, Norwich, UK
| | - Paul Williams
- National Biofilms Innovation Centre, Biodiscovery Institute and School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Stephan Heeb
- National Biofilms Innovation Centre, Biodiscovery Institute and School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Miguel Cámara
- National Biofilms Innovation Centre, Biodiscovery Institute and School of Life Sciences, University of Nottingham, Nottingham, UK.
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16
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Palma V, Gutiérrez MS, Vargas O, Parthasarathy R, Navarrete P. Methods to Evaluate Bacterial Motility and Its Role in Bacterial–Host Interactions. Microorganisms 2022; 10:microorganisms10030563. [PMID: 35336138 PMCID: PMC8953368 DOI: 10.3390/microorganisms10030563] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 02/02/2022] [Accepted: 02/06/2022] [Indexed: 11/16/2022] Open
Abstract
Bacterial motility is a widespread characteristic that can provide several advantages for the cell, allowing it to move towards more favorable conditions and enabling host-associated processes such as colonization. There are different bacterial motility types, and their expression is highly regulated by the environmental conditions. Because of this, methods for studying motility under realistic experimental conditions are required. A wide variety of approaches have been developed to study bacterial motility. Here, we present the most common techniques and recent advances and discuss their strengths as well as their limitations. We classify them as macroscopic or microscopic and highlight the advantages of three-dimensional imaging in microscopic approaches. Lastly, we discuss methods suited for studying motility in bacterial–host interactions, including the use of the zebrafish model.
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Affiliation(s)
- Victoria Palma
- Laboratory of Microbiology and Probiotics, Institute of Nutrition and Food Technology (INTA), University of Chile, El Líbano 5524, Santiago 7830490, Chile; (V.P.); (M.S.G.); (O.V.)
| | - María Soledad Gutiérrez
- Laboratory of Microbiology and Probiotics, Institute of Nutrition and Food Technology (INTA), University of Chile, El Líbano 5524, Santiago 7830490, Chile; (V.P.); (M.S.G.); (O.V.)
- Millennium Science Initiative Program, Milenium Nucleus in the Biology of the Intestinal Microbiota, National Agency for Research and Development (ANID), Moneda 1375, Santiago 8200000, Chile
| | - Orlando Vargas
- Laboratory of Microbiology and Probiotics, Institute of Nutrition and Food Technology (INTA), University of Chile, El Líbano 5524, Santiago 7830490, Chile; (V.P.); (M.S.G.); (O.V.)
| | - Raghuveer Parthasarathy
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA;
- Department of Physics and Materials Science Institute, University of Oregon, Eugene, OR 97403, USA
| | - Paola Navarrete
- Laboratory of Microbiology and Probiotics, Institute of Nutrition and Food Technology (INTA), University of Chile, El Líbano 5524, Santiago 7830490, Chile; (V.P.); (M.S.G.); (O.V.)
- Millennium Science Initiative Program, Milenium Nucleus in the Biology of the Intestinal Microbiota, National Agency for Research and Development (ANID), Moneda 1375, Santiago 8200000, Chile
- Correspondence:
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17
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Liu XY, Guo S, Bocklitz T, Rösch P, Popp J, Yu HQ. Nondestructive 3D imaging and quantification of hydrated biofilm matrix by confocal Raman microscopy coupled with non-negative matrix factorization. WATER RESEARCH 2022; 210:117973. [PMID: 34959065 DOI: 10.1016/j.watres.2021.117973] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 11/30/2021] [Accepted: 12/14/2021] [Indexed: 06/14/2023]
Abstract
Biofilms are ubiquitous in natural and engineered environments and of great importance in drinking water distribution and biological wastewater treatment systems. Simultaneously acquiring the chemical and structural information of the hydrated biofilm matrix is essential for the cognition and regulation of biofilms in the environmental field. However, the complexity of samples and the limited approaches prevent a holistic understanding of the biofilm matrix. In this work, an approach based on the confocal Raman mapping technique integrated with non-negative matrix factorization (NMF) analysis was developed to probe the hydrated biofilm matrix in situ. The flexibility of the NMF analysis was utilized to subtract the undesired water background signal and resolve the meaningful biological components from Raman spectra of the hydrated biofilms. Diverse chemical components such as proteins, bacterial cells, glycolipids and polyhydroxyalkanoates (PHA) were unraveled within the distinct Pseudomonas spp. biofilm matrices, and the corresponding 3-dimensional spatial organization was visualized and quantified. Of these components, glycolipids and PHA were unique to the P. aeruginosa and P. putida biofilm matrix, respectively. Furthermore, their high abundances in the lower region of the biofilm matrix were found to be related to the specific physiological functions and surrounding microenvironments. Overall, the results demonstrate that our NMF Raman mapping method could serve as a powerful tool complementary to the conventional approaches for identifying and visualizing the chemical components in the biofilm matrix. This work may facilitate the online characterization of the biofilm matrix widely present in the environment and advance the fundamental understanding of biofilm.
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Affiliation(s)
- Xiao-Yang Liu
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China; School of Energy & Environmental Engineering, Hebei University of Technology, Tianjin 300130, China; Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, Helmholtzweg 4, Jena D-07743, Germany; InfectoGnostics Research Campus Jena, Philosophenweg 7, Jena D-07743, Germany
| | - Shuxia Guo
- Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, Helmholtzweg 4, Jena D-07743, Germany; Leibniz Institute of Photonic Technology Jena - Member of the Research Alliance "Leibniz Health Technologies", Albert-Einstein-Strasse 9, Jena D-07745, Germany
| | - Thomas Bocklitz
- Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, Helmholtzweg 4, Jena D-07743, Germany; Leibniz Institute of Photonic Technology Jena - Member of the Research Alliance "Leibniz Health Technologies", Albert-Einstein-Strasse 9, Jena D-07745, Germany
| | - Petra Rösch
- Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, Helmholtzweg 4, Jena D-07743, Germany; InfectoGnostics Research Campus Jena, Philosophenweg 7, Jena D-07743, Germany
| | - Jürgen Popp
- Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, Helmholtzweg 4, Jena D-07743, Germany; InfectoGnostics Research Campus Jena, Philosophenweg 7, Jena D-07743, Germany; Center for Sepsis Control and Care (CSCC), Jena University Hospital, Am Klinikum 1, Jena D-07743, Germany; Leibniz Institute of Photonic Technology Jena - Member of the Research Alliance "Leibniz Health Technologies", Albert-Einstein-Strasse 9, Jena D-07745, Germany.
| | - Han-Qing Yu
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China.
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18
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Abstract
The opportunistic human pathogen Pseudomonas aeruginosa is known for exhibiting diverse forms of collective behaviors, like swarming motility and biofilm formation. Swarming in P. aeruginosa is a collective movement of the bacterial population over a semisolid surface, but specific swarming signals are not clear. We hypothesize that specific environmental signals induce swarming in P. aeruginosa. We show that under nutrient-limiting conditions, a low concentration of ethanol provides a strong ecological motivation for swarming in P. aeruginosa strain PA14. Ethanol serves as a signal and not a source of carbon under these conditions. Moreover, ethanol-driven swarming relies on the ability of the bacteria to metabolize ethanol to acetaldehyde using a periplasmic quinoprotein alcohol dehydrogenase, ExaA. We found that ErdR, an orphan response regulator linked to ethanol oxidation, is necessary for the transcriptional regulation of a cluster of 17 genes, including exaA, during swarm lag. Further, we show that P. aeruginosa displays characteristic foraging motility on a lawn of Cryptococcus neoformans, a yeast species, in a manner dependent on the ethanol dehydrogenase ErdR and on rhamnolipids. Finally, we show that ethanol, as a volatile, could induce swarming in P. aeruginosa at a distance, suggesting long-range spatial effects of ethanol as a signaling molecule.
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19
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Romero-Severson J, Moran TE, Shrader DG, Fields FR, Pandey-Joshi S, Thomas CL, Palmer EC, Shrout JD, Pfrender ME, Lee SW. A Seed-Endophytic Bacillus safensis Strain With Antimicrobial Activity Has Genes for Novel Bacteriocin-Like Antimicrobial Peptides. Front Microbiol 2021; 12:734216. [PMID: 34646254 PMCID: PMC8503640 DOI: 10.3389/fmicb.2021.734216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 08/20/2021] [Indexed: 12/04/2022] Open
Abstract
Bacteriocins are a highly diverse group of antimicrobial peptides that have been identified in a wide range of commensal and probiotic organisms, especially those resident in host microbiomes. Rising antibiotic resistance have fueled renewed research into new drug scaffolds such as antimicrobial peptides for use in therapeutics. In this investigation, we examined mung bean seeds for endophytes possessing activity against human and plant pathogens. We isolated a novel strain of Bacillus safensis, from the contents of surface-sterilized mung bean seed, which we termed B. safensis C3. Genome sequencing of C3 identified three distinct biosynthetic systems that produce bacteriocin-based peptides. C3 exhibited antibacterial activity against Escherichia coli, Xanthomonas axonopodis, and Pseudomonas syringae. Robust antimicrobial activity of B. safensis C3 was observed when C3 was co-cultured with Bacillus subtilis. Using the cell-free supernatant of C3 and cation exchange chromatography, we enriched a product that retained antimicrobial activity against B. subtilis. The peptide was found to be approximately 3.3 kDa in size by mass spectrometry, and resistant to proteolysis by Carboxypeptidase Y and Endoproteinase GluC, suggesting that it is a modified variant of an AS-48 like bacteriocin. Our findings open new avenues into further development of novel bacteriocin-based scaffolds for therapeutic development, as well as further investigations into how our discoveries of bacteriocin-producing plant commensal microorganisms may have the potential for an immediate impact on the safety of food supplies.
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Affiliation(s)
- Jeanne Romero-Severson
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, United States
| | - Thomas E Moran
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, United States
| | - Donna G Shrader
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, United States
| | - Francisco R Fields
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, United States
| | - Susan Pandey-Joshi
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, United States
| | - Clayton L Thomas
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, United States
| | - Emily C Palmer
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, United States.,Department of Civil and Environmental Engineering, University of Notre Dame, Notre Dame, IN, United States
| | - Joshua D Shrout
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, United States.,Department of Civil and Environmental Engineering, University of Notre Dame, Notre Dame, IN, United States
| | - Michael E Pfrender
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, United States
| | - Shaun W Lee
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, United States
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20
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Byju AS, Patel D, Chen W, Mani S. Assessing Swarming of Aerobic Bacteria from Human Fecal Matter. Bio Protoc 2021; 11:e4008. [PMID: 34124308 DOI: 10.21769/bioprotoc.4008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 01/10/2021] [Accepted: 03/12/2021] [Indexed: 11/02/2022] Open
Abstract
Swarming - swift movement across a surface via flagella propulsion - is a unique property of many bacteria. The role of swarming, particularly among bacterial populations of the human gut microbiome, is not yet fully understood; although, it is becoming an area of increased scientific and clinical inquiry. To further characterize bacterial swarming in human health, an effective assay for swarming that utilizes complex material, such as fecal matter, is necessary. Until now, the vast majority of swarming assays have only been able to accommodate bacteria grown in culture, most often Pseudomonas. These assays tend to use a standard lysogenic broth (LB) agar medium; however, the reagents involved have not been tailored to the inoculation of complex material. In this paper, we offer a specialized protocol for eliciting the swarming of bacteria from frozen human fecal samples. We describe the simple, yet reproducible steps required to perform the assay, identifying an ideal volume of 7.5 μl for inoculation of material, as well as an ideal agar concentration of 0.4%. This protocol typically allows researchers to identify swarming within 24 h after incubation in a standard incubator.
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Affiliation(s)
- Arjun S Byju
- Department of Medicine, Genetics, and Molecular Pharmacology, Albert Einstein College of Medicine Bronx, NY, USA
| | - Deeti Patel
- Department of Medicine, Genetics, and Molecular Pharmacology, Albert Einstein College of Medicine Bronx, NY, USA
| | - Weijie Chen
- Department of Medicine, Genetics, and Molecular Pharmacology, Albert Einstein College of Medicine Bronx, NY, USA
| | - Sridhar Mani
- Department of Medicine, Genetics, and Molecular Pharmacology, Albert Einstein College of Medicine Bronx, NY, USA
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21
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Motta JP, Wallace JL, Buret AG, Deraison C, Vergnolle N. Gastrointestinal biofilms in health and disease. Nat Rev Gastroenterol Hepatol 2021; 18:314-334. [PMID: 33510461 DOI: 10.1038/s41575-020-00397-y] [Citation(s) in RCA: 90] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/25/2020] [Indexed: 01/30/2023]
Abstract
Microorganisms colonize various ecological niches in the human habitat, as they do in nature. Predominant forms of multicellular communities called biofilms colonize human tissue surfaces. The gastrointestinal tract is home to a profusion of microorganisms with intertwined, but not identical, lifestyles: as isolated planktonic cells, as biofilms and in biofilm-dispersed form. It is therefore of major importance in understanding homeostatic and altered host-microorganism interactions to consider not only the planktonic lifestyle, but also biofilms and biofilm-dispersed forms. In this Review, we discuss the natural organization of microorganisms at gastrointestinal surfaces, stratification of microbiota taxonomy, biogeographical localization and trans-kingdom interactions occurring within the biofilm habitat. We also discuss existing models used to study biofilms. We assess the contribution of the host-mucosa biofilm relationship to gut homeostasis and to diseases. In addition, we describe how host factors can shape the organization, structure and composition of mucosal biofilms, and how biofilms themselves are implicated in a variety of homeostatic and pathological processes in the gut. Future studies characterizing biofilm nature, physical properties, composition and intrinsic communication could shed new light on gut physiology and lead to potential novel therapeutic options for gastrointestinal diseases.
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Affiliation(s)
- Jean-Paul Motta
- Institute of Digestive Health Research, IRSD, INSERM U1220, Toulouse, France.
| | - John L Wallace
- Department of Physiology & Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Antibe Therapeutics Inc., Toronto, ON, Canada
| | - André G Buret
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Céline Deraison
- Institute of Digestive Health Research, IRSD, INSERM U1220, Toulouse, France
| | - Nathalie Vergnolle
- Institute of Digestive Health Research, IRSD, INSERM U1220, Toulouse, France. .,Department of Physiology & Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.
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22
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Ma H, Bell J, Chen W, Mani S, Tang JX. An expanding bacterial colony forms a depletion zone with growing droplets. SOFT MATTER 2021; 17:2315-2326. [PMID: 33480951 PMCID: PMC8608367 DOI: 10.1039/d0sm01348j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Many species of bacteria have developed effective means to spread on solid surfaces. This study focuses on the expansion of Pseudomonas aeruginosa on an agar gel surface under conditions of minimal evaporation. We report the occurrence and spread of a depletion zone within an expanded colony, where the bacteria laden film becomes thinner. The depletion zone is colocalized with a higher concentration of rhamnolipids, the biosurfactants that are produced by the bacteria and accumulate in the older region of the colony. With continued growth in population, dense bacterial droplets occur and coalesce in the depletion zone, displaying remarkable fluid dynamic behavior. Whereas expansion of a central depletion zone requires activities of live bacteria, new zones can be seeded elsewhere by adding rhamnolipids. These depletion zones due to the added surfactants expand quickly, even on plates covered by bacteria that have been killed by ultraviolet light. We explain the observed properties based on considerations of bacterial growth and secretion, osmotic swelling, fluid volume expansion, interfacial fluid dynamics involving Marangoni and capillary flows, and cell-cell cohesion.
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Affiliation(s)
- Hui Ma
- Physics Department, Brown University, Providence, RI, USA.
| | - Jordan Bell
- Physics Department, Brown University, Providence, RI, USA.
| | - Weijie Chen
- Physics Department, Brown University, Providence, RI, USA. and Department of Medicine, Genetics and Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Sridhar Mani
- Department of Medicine, Genetics and Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Jay X Tang
- Physics Department, Brown University, Providence, RI, USA.
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23
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Espeso DR, Algar E, Martínez-García E, de Lorenzo V. Exploiting geometric similarity for statistical quantification of fluorescence spatial patterns in bacterial colonies. BMC Bioinformatics 2020; 21:224. [PMID: 32493227 PMCID: PMC7268344 DOI: 10.1186/s12859-020-3490-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 04/13/2020] [Indexed: 11/10/2022] Open
Abstract
Background Currently the combination of molecular tools, imaging techniques and analysis software offer the possibility of studying gene activity through the use of fluorescent reporters and infer its distribution within complex biological three-dimensional structures. For example, the use of Confocal Scanning Laser Microscopy (CSLM) is a regularly-used approach to visually inspect the spatial distribution of a fluorescent signal. Although a plethora of generalist imaging software is available to analyze experimental pictures, the development of tailor-made software for every specific problem is still the most straightforward approach to perform the best possible image analysis. In this manuscript, we focused on developing a simple methodology to satisfy one particular need: automated processing and analysis of CSLM image stacks to generate 3D fluorescence profiles showing the average distribution detected in bacterial colonies grown in different experimental conditions for comparison purposes. Results The presented method processes batches of CSLM stacks containing three-dimensional images of an arbitrary number of colonies. Quasi-circular colonies are identified, filtered and projected onto a normalized orthogonal coordinate system, where a numerical interpolation is performed to obtain fluorescence values within a spatially fixed grid. A statistically representative three-dimensional fluorescent pattern is then generated from this data, allowing for standardized fluorescence analysis regardless of variability in colony size. The proposed methodology was evaluated by analyzing fluorescence from GFP expression subject to regulation by a stress-inducible promoter. Conclusions This method provides a statistically reliable spatial distribution profile of fluorescence detected in analyzed samples, helping the researcher to establish general correlations between gene expression and spatial allocation under differential experimental regimes. The described methodology was coded into a MATLAB script and shared under an open source license to make it accessible to the whole community.
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Affiliation(s)
- David R Espeso
- Systems Biology Program, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, 28049, Madrid, Spain
| | - Elena Algar
- Systems Biology Program, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, 28049, Madrid, Spain
| | - Esteban Martínez-García
- Systems Biology Program, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, 28049, Madrid, Spain
| | - Víctor de Lorenzo
- Systems Biology Program, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, 28049, Madrid, Spain.
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24
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Madukoma CS, Liang P, Dimkovikj A, Chen J, Lee SW, Chen DZ, Shrout JD. Single Cells Exhibit Differing Behavioral Phases during Early Stages of Pseudomonas aeruginosa Swarming. J Bacteriol 2019; 201:e00184-19. [PMID: 31308071 PMCID: PMC6755744 DOI: 10.1128/jb.00184-19] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 07/09/2019] [Indexed: 12/23/2022] Open
Abstract
Pseudomonas aeruginosa is among the many bacteria that swarm, where groups of cells coordinate to move over surfaces. It has been challenging to determine the behavior of single cells within these high-cell-density swarms. To track individual cells within P. aeruginosa swarms, we imaged a fluorescently labeled subset of the larger population. Single cells at the advancing swarm edge varied in their motility dynamics as a function of time. From these data, we delineated four phases of early swarming prior to the formation of the tendril fractals characteristic of P. aeruginosa swarming by collectively considering both micro- and macroscale data. We determined that the period of greatest single-cell motility does not coincide with the period of greatest collective swarm expansion. We also noted that flagellar, rhamnolipid, and type IV pilus motility mutants exhibit substantially less single-cell motility than the wild type.IMPORTANCE Numerous bacteria exhibit coordinated swarming motion over surfaces. It is often challenging to assess the behavior of single cells within swarming communities due to the limitations of identifying, tracking, and analyzing the traits of swarming cells over time. Here, we show that the behavior of Pseudomonas aeruginosa swarming cells can vary substantially in the earliest phases of swarming. This is important to establish that dynamic behaviors should not be assumed to be constant over long periods when predicting and simulating the actions of swarming bacteria.
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Affiliation(s)
- Chinedu S Madukoma
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Peixian Liang
- Department of Computer Science and Engineering, University of Notre Dame, Notre Dame, Indiana, USA
| | - Aleksandar Dimkovikj
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Jianxu Chen
- Department of Computer Science and Engineering, University of Notre Dame, Notre Dame, Indiana, USA
| | - Shaun W Lee
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Danny Z Chen
- Department of Computer Science and Engineering, University of Notre Dame, Notre Dame, Indiana, USA
| | - Joshua D Shrout
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana, USA
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
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25
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Fu TK, Ng SK, Chen YE, Lee YC, Demeter F, Herczeg M, Borbás A, Chiu CH, Lan CY, Chen CL, Chang MDT. Rhamnose Binding Protein as an Anti-Bacterial Agent-Targeting Biofilm of Pseudomonas aeruginosa. Mar Drugs 2019; 17:md17060355. [PMID: 31207891 PMCID: PMC6628293 DOI: 10.3390/md17060355] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 06/11/2019] [Accepted: 06/12/2019] [Indexed: 01/14/2023] Open
Abstract
More than 80% of infectious bacteria form biofilm, which is a bacterial cell community surrounded by secreted polysaccharides, proteins and glycolipids. Such bacterial superstructure increases resistance to antimicrobials and host defenses. Thus, to control these biofilm-forming pathogenic bacteria requires antimicrobial agents with novel mechanisms or properties. Pseudomonas aeruginosa, a Gram-negative opportunistic nosocomial pathogen, is a model strain to study biofilm development and correlation between biofilm formation and infection. In this study, a recombinant hemolymph plasma lectin (rHPLOE) cloned from Taiwanese Tachypleus tridentatus was expressed in an Escherichia coli system. This rHPLOE was shown to have the following properties: (1) Binding to P. aeruginosa PA14 biofilm through a unique molecular interaction with rhamnose-containing moieties on bacteria, leading to reduction of extracellular di-rhamnolipid (a biofilm regulator); (2) decreasing downstream quorum sensing factors, and inhibiting biofilm formation; (3) dispersing the mature biofilm of P. aeruginosa PA14 to improve the efficacies of antibiotics; (4) reducing P. aeruginosa PA14 cytotoxicity to human lung epithelial cells in vitro and (5) inhibiting P. aeruginosa PA14 infection of zebrafish embryos in vivo. Taken together, rHPLOE serves as an anti-biofilm agent with a novel mechanism of recognizing rhamnose moieties in lipopolysaccharides, di-rhamnolipid and structural polysaccharides (Psl) in biofilms. Thus rHPLOE links glycan-recognition to novel anti-biofilm strategies against pathogenic bacteria.
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Affiliation(s)
- Tse-Kai Fu
- Institute of Molecular and Cellular Biology, National Tsing Hua University, Hsinchu 30013, Taiwan.
- Simpson Biotech Co., Ltd., Taoyuan 333, Taiwan.
| | - Sim-Kun Ng
- Institute of Molecular and Cellular Biology, National Tsing Hua University, Hsinchu 30013, Taiwan.
| | - Yi-En Chen
- Institute of Molecular and Cellular Biology, National Tsing Hua University, Hsinchu 30013, Taiwan.
| | - Yuan-Chuan Lee
- Institute of Molecular and Cellular Biology, National Tsing Hua University, Hsinchu 30013, Taiwan.
- Department of Biology, Johns Hopkins University, Baltimore, ML 21218, USA.
| | - Fruzsina Demeter
- Department of Pharmaceutical Chemistry, University of Debrecen, Debrecen 4032, Hungary (F.D.).
| | - Mihály Herczeg
- Department of Pharmaceutical Chemistry, University of Debrecen, Debrecen 4032, Hungary (F.D.).
| | - Anikó Borbás
- Department of Pharmaceutical Chemistry, University of Debrecen, Debrecen 4032, Hungary (F.D.).
| | - Cheng-Hsun Chiu
- Department of Life Science, National Tsing Hua University, Hsinchu 30013, Taiwan.
| | - Chung-Yu Lan
- Institute of Molecular and Cellular Biology, National Tsing Hua University, Hsinchu 30013, Taiwan.
- Department of Life Science, National Tsing Hua University, Hsinchu 30013, Taiwan.
| | - Chyi-Liang Chen
- Molecular Infectious Disease Research Center, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan 333, Taiwan.
| | - Margaret Dah-Tsyr Chang
- Institute of Molecular and Cellular Biology, National Tsing Hua University, Hsinchu 30013, Taiwan.
- Department of Life Science, National Tsing Hua University, Hsinchu 30013, Taiwan.
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26
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Kollaran AM, Joge S, Kotian HS, Badal D, Prakash D, Mishra A, Varma M, Singh V. Context-Specific Requirement of Forty-Four Two-Component Loci in Pseudomonas aeruginosa Swarming. iScience 2019; 13:305-317. [PMID: 30877999 PMCID: PMC6423354 DOI: 10.1016/j.isci.2019.02.028] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 12/18/2018] [Accepted: 02/26/2019] [Indexed: 11/30/2022] Open
Abstract
Swarming in Pseudomonas aeruginosa is a coordinated movement of bacteria over semisolid surfaces (0.5%-0.7% agar). On soft agar, P. aeruginosa exhibits a dendritic swarm pattern, with multiple levels of branching. However, the swarm patterns typically vary depending upon the experimental design. In the present study, we show that the pattern characteristics of P. aeruginosa swarm are highly environment dependent. We define several quantifiable, macroscale features of the swarm to study the plasticity of the swarm, observed across different nutrient formulations. Furthermore, through a targeted screen of 113 two-component system (TCS) loci of the P. aeruginosa strain PA14, we show that forty-four TCS genes regulate swarming in PA14 in a contextual fashion. However, only four TCS genes-fleR, fleS, gacS, and PA14_59770-were found essential for swarming. Notably, many swarming-defective TCS mutants were found highly efficient in biofilm formation, indicating opposing roles for many TCS loci.
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Affiliation(s)
- Ameen M Kollaran
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Shubham Joge
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Harshitha S Kotian
- Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Divakar Badal
- Biosystems Science and Engineering, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Deep Prakash
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Ayushi Mishra
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Manoj Varma
- Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore, Karnataka 560012, India; Robert Bosch Centre for Cyber Physical Systems, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Varsha Singh
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, Karnataka 560012, India; Biosystems Science and Engineering, Indian Institute of Science, Bangalore, Karnataka 560012, India.
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27
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Hendiani S, Pornour M, Kashef N. Quorum-sensing-regulated virulence factors in Pseudomonas aeruginosa are affected by sub-lethal photodynamic inactivation. Photodiagnosis Photodyn Ther 2019; 26:8-12. [PMID: 30753921 DOI: 10.1016/j.pdpdt.2019.02.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 01/02/2019] [Accepted: 02/08/2019] [Indexed: 11/15/2022]
Abstract
BACKGROUND Photodynamic inactivation (PDI) is recognized as a new antimicrobial approach. It is likely that in human hosts receiving this therapy, pathogens may encounter sub-lethal doses of PDI (sPDI), which may affect microbial virulence. This study was aimed to evaluate the effect of sPDI using methylene blue (MB) on the expression of genes belonging to two quorum sensing (QS) operons (rhl and las systems) and two genes necessary for pyocyanin and rhamnolipid production (phzM and rhlA) under QS control in Pseudomonas aeruginosa. METHODS Ability of pyocyanin and rhamnolipid production of P. aeruginosa ATCC 27853 and clinical isolates exposed to sPDI (MB at 0.012 mM and light dose of 23 J/cm2 was evaluated. The effect of sPDI on expression of rhlI, rhlR, lasI, lasR, phzM and rhlA were also evaluated by quantitative real time polymerase chain reaction. RESULTS sPDI led to the down-regulation of the expression of all four QS genes (lasI, lasR, rhlI and rhlR) and rhamnolipid gene (rhlA). However, up-regulation of pyocyanin gene (phzM) was observed after sPDI. These results were consistent with phenotypic changes. CONCLUSION This study suggests that oxidative stress induced by sPDI can affect QS-regulated virulence factors of P. aeruginosa such as pyocyanin and rhamnolipids in different ways.
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Affiliation(s)
- Saghar Hendiani
- Department of Microbiology, School of Biology, College of Science, University of Tehran, Tehran, Iran.
| | - Majid Pornour
- Department of Photo Healing and Regeneration, Medical Laser Research Center, Yara Institute, Academic Center for Education, Culture and Research (ACECR), Tehran, Iran.
| | - Nasim Kashef
- Department of Microbiology, School of Biology, College of Science, University of Tehran, Tehran, Iran.
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28
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Cao T, Morales-Soto N, Jia J, Baig NF, Dunham SJB, Ellis J, Sweedler JV, Shrout JD, Bohn PW. Spatiotemporal Dynamics of Molecular Messaging in Bacterial Co-Cultures Studied by Multimodal Chemical Imaging. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2019; 10863:108630A. [PMID: 33790492 PMCID: PMC8009051 DOI: 10.1117/12.2501349] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Microbial community behavior is coupled to a set of genetically-regulated chemical signals that correlate with cell density - the quorum sensing (QS) system - and there is growing appreciation that the QS-regulated behavior of bacteria is chemically, spatially, and temporally complex. In addition, while it has been known for some time that different species use different QS networks, we are beginning to appreciate that different strains of the same bacterial species also differ in their QS networks. Here we combine mass spectrometric imaging (MSI) and confocal Raman microscopy (CRM) approaches to investigate co-cultures involving different strains (FRD1 and PAO1C) of the same species (Pseudomonas aeruginosa) as well as those involving different species (P. aeruginosa and E. coli). Combining MSI and CRM makes it possible to supersede the limits imposed by individual imaging approaches and enables the spatial mapping of individual bacterial species and their microbial products within a mixed bacterial community growing in situ on surfaces. MSI is used to delineate the secretion of a specific rhamnolipid surfactant as well as alkyl quinolone (AQ) messengers between FRD1 and PAO1C strains of P. aeruginosa, showing that the spatial distribution and production rate of AQ messengers in PAO1C far outstrips that of FRD1. In the case of multiple species, CRM is used to show that the prolific secretion of AQs by the PAO1C strain of P. aeruginosa is used to mediate its interaction with co-cultured E. coli.
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Affiliation(s)
- Tianyuan Cao
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, USA
| | - Nydia Morales-Soto
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Jin Jia
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, USA
| | - Nameera F Baig
- Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720
| | - Sage J B Dunham
- Entech Instruments, 2207 Agate Court, Simi Valley, CA 93065
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Ave., Urbana, IL 61801
| | - Joseph Ellis
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Ave., Urbana, IL 61801
| | - Jonathan V Sweedler
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Ave., Urbana, IL 61801
| | - Joshua D Shrout
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, IN, USA
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Paul W Bohn
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, USA
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN, USA
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29
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Abstract
The opportunistic pathogen Proteus mirabilis engages in visually dramatic and dynamic social behaviors. Populations of P. mirabilis can rapidly occupy surfaces, such as high-percentage agar and latex, through a collective surface-based motility termed swarming. When in these surface-occupying swarm colonies, P. mirabilis can distinguish between clonal siblings (self) and foreign P. mirabilis strains (nonself). This ability can be assessed by at least two standard methods: boundary formation, aka a Dienes line, and territorial exclusion. Here we describe methods for quantitative analysis of swarm colony expansion, of boundary formation, and of territorial exclusion. These assays can be employed to assess several aspects of P. mirabilis sociality including collective swarm motility, competition, and self versus nonself recognition.
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Affiliation(s)
- Kristin Little
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
| | - Karine A Gibbs
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA.
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30
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Asif A, Iftikhar A, Hamood A, Colmer-Hamood JA, Qaisar U. Isonitrile-functionalized tyrosine modulates swarming motility and quorum sensing in Pseudomonas aeruginosa. Microb Pathog 2018; 127:288-295. [PMID: 30528249 DOI: 10.1016/j.micpath.2018.12.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 12/02/2018] [Accepted: 12/03/2018] [Indexed: 11/16/2022]
Abstract
Paerucumarin synthesized by pvc operon pvcABCD is an iron binding molecule which modulates biofilm formation in Pseudomonas aeruginosa but its direct function in bacterial pathogenesis needs further investigation. pvcA synthesizes isonitrile functionalized tyrosine (IFT) which is converted to mature paerucumarin by the proteins encoded by pvcB, pvcC and pvcD genes. Interruption of pvcB in MPAO1 resulted in accumulation of IFT as it cannot be converted to mature molecule. The MPAO1 pvcB mutant (PW4832) showed enhanced swarming motility, while complementation with plasmid pLL2 carrying pvcB reduced swarming motility. Enhanced levels of rhlA expression and rhamnolipid production were observed in PW4832 compared to the parent strain. Overexpression of ptxR, the positive regulator of pvcABCD, in PW4832 caused accumulation of more IFT and further elevated the level of rhlA expression. Expression of the quorum sensing system transcriptional activators lasR and rhlR, as well as the synthase genes lasI and rhlI, was enhanced in PW4832 compared to MPAO1, as was PQS accumulation. Exogenously added IFT, but not paerucumarin, enhanced the production of rhamnolipids in P. aeruginosa. These results suggest that IFT enhances swarming motility in P. aeruginosa either directly by enhancing rhamnolipid production or indirectly through modulation of the quorum sensing systems. This is the first report assigning an independent function to IFT in P. aeruginosa.
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Affiliation(s)
- Azka Asif
- School of Biological Sciences, University of the Punjab, Lahore, Pakistan
| | - Anam Iftikhar
- School of Biological Sciences, University of the Punjab, Lahore, Pakistan
| | - Abdul Hamood
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, 79430, USA
| | - Jane A Colmer-Hamood
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, 79430, USA; Department of Medical Education, Texas Tech University Health Sciences Center, Lubbock, TX, 79430, USA
| | - Uzma Qaisar
- School of Biological Sciences, University of the Punjab, Lahore, Pakistan.
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31
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Goswami M, Espinasse A, Carlson EE. Disarming the virulence arsenal of Pseudomonas aeruginosa by blocking two-component system signaling. Chem Sci 2018; 9:7332-7337. [PMID: 30542536 PMCID: PMC6237130 DOI: 10.1039/c8sc02496k] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 07/06/2018] [Indexed: 12/31/2022] Open
Abstract
Pseudomonas aeruginosa infections have reached a “critical” threat status making novel therapeutic approaches required.
Pseudomonas aeruginosa infections have reached a “critical” threat status making novel therapeutic approaches required. Inhibiting key signaling enzymes known as the histidine kinases (HKs), which are heavily involved with its pathogenicity, has been postulated to be an effective new strategy for treatment. Herein, we demonstrate the potential of this approach with benzothiazole-based HK inhibitors that perturb multiple virulence pathways in the burn wound P. aeruginosa isolate, PA14. Specifically, our compounds significantly reduce the level of toxic metabolites generated by this organism that are involved in quorum-sensing and redox-balancing mechanisms. They also decrease the ability of this organism to swarm and attach to surfaces, likely by influencing their motility appendages. Quantitative transcription analysis of inhibitor-treated cultures showed substantial perturbations to multiple pathways including expression of response regulator GacA, the cognate partner of the “super regulator” of virulence, HK GacS, as well as flagella and pili formation. These promising results establish that blocking of bacterial signaling in P. aeruginosa has dramatic consequences on virulence behaviours, especially in the context of surface-associated infections.
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Affiliation(s)
- Manibarsha Goswami
- Department of Chemistry , University of Minnesota , 225 Pleasant St. SE , Minneapolis , MN 55454 , USA .
| | - Adeline Espinasse
- Department of Chemistry , University of Minnesota , 225 Pleasant St. SE , Minneapolis , MN 55454 , USA .
| | - Erin E Carlson
- Department of Chemistry , University of Minnesota , 225 Pleasant St. SE , Minneapolis , MN 55454 , USA . .,Department of Medicinal Chemistry , University of Minnesota , USA.,Department of Biochemistry, Molecular Biology and Biophysics , University of Minnesota , USA
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32
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Morales-Soto N, Dunham SJB, Baig NF, Ellis JF, Madukoma CS, Bohn PW, Sweedler JV, Shrout JD. Spatially dependent alkyl quinolone signaling responses to antibiotics in Pseudomonas aeruginosa swarms. J Biol Chem 2018; 293:9544-9552. [PMID: 29588364 DOI: 10.1074/jbc.ra118.002605] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 03/22/2018] [Indexed: 11/06/2022] Open
Abstract
There is a general lack of understanding about how communities of bacteria respond to exogenous toxins such as antibiotics. Most of our understanding of community-level stress responses comes from the study of stationary biofilm communities. Although several community behaviors and production of specific biomolecules affecting biofilm development and associated behavior have been described for Pseudomonas aeruginosa and other bacteria, we have little appreciation for the production and dispersal of secreted metabolites within the 2D and 3D spaces they occupy as they colonize, spread, and grow on surfaces. Here we specifically studied the phenotypic responses and spatial variability of alkyl quinolones, including the Pseudomonas quinolone signal (PQS) and members of the alkyl hydroxyquinoline (AQNO) subclass, in P. aeruginosa plate-assay swarming communities. We found that PQS production was not a universal signaling response to antibiotics, as tobramycin elicited an alkyl quinolone response, whereas carbenicillin did not. We also found that PQS and AQNO profiles in response to tobramycin were markedly distinct and influenced these swarms on different spatial scales. At some tobramycin exposures, P. aeruginosa swarms produced alkyl quinolones in the range of 150 μm PQS and 400 μm AQNO that accumulated as aggregates. Our collective findings show that the distribution of alkyl quinolones can vary by several orders of magnitude within the same swarming community. More notably, our results suggest that multiple intercellular signals acting on different spatial scales can be triggered by one common cue.
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Affiliation(s)
- Nydia Morales-Soto
- From the Departments of Civil and Environmental Engineering and Earth Sciences
| | - Sage J B Dunham
- the Department of Chemistry and the Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | | | - Joseph F Ellis
- the Department of Chemistry and the Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Chinedu S Madukoma
- From the Departments of Civil and Environmental Engineering and Earth Sciences
| | - Paul W Bohn
- Chemistry and Biochemistry.,Chemical and Biomolecular Engineering, and
| | - Jonathan V Sweedler
- the Department of Chemistry and the Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Joshua D Shrout
- From the Departments of Civil and Environmental Engineering and Earth Sciences, .,Biological Sciences, University of Notre Dame, Notre Dame, Indiana 46556 and
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33
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Palos Pacheco R, Eismin RJ, Coss CS, Wang H, Maier RM, Polt R, Pemberton JE. Synthesis and Characterization of Four Diastereomers of Monorhamnolipids. J Am Chem Soc 2017; 139:5125-5132. [DOI: 10.1021/jacs.7b00427] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Ricardo Palos Pacheco
- Department
of Chemistry and Biochemistry and ‡Department of Soil, Water and Environmental
Science, University of Arizona, Tucson, Arizona 85721, United States
| | - Ryan J. Eismin
- Department
of Chemistry and Biochemistry and ‡Department of Soil, Water and Environmental
Science, University of Arizona, Tucson, Arizona 85721, United States
| | - Clifford S. Coss
- Department
of Chemistry and Biochemistry and ‡Department of Soil, Water and Environmental
Science, University of Arizona, Tucson, Arizona 85721, United States
| | - Hui Wang
- Department
of Chemistry and Biochemistry and ‡Department of Soil, Water and Environmental
Science, University of Arizona, Tucson, Arizona 85721, United States
| | - Raina M. Maier
- Department
of Chemistry and Biochemistry and ‡Department of Soil, Water and Environmental
Science, University of Arizona, Tucson, Arizona 85721, United States
| | - Robin Polt
- Department
of Chemistry and Biochemistry and ‡Department of Soil, Water and Environmental
Science, University of Arizona, Tucson, Arizona 85721, United States
| | - Jeanne E. Pemberton
- Department
of Chemistry and Biochemistry and ‡Department of Soil, Water and Environmental
Science, University of Arizona, Tucson, Arizona 85721, United States
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34
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Growth-altering microbial interactions are responsive to chemical context. PLoS One 2017; 12:e0164919. [PMID: 28319121 PMCID: PMC5358735 DOI: 10.1371/journal.pone.0164919] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 02/27/2017] [Indexed: 11/20/2022] Open
Abstract
Microbial interactions are ubiquitous in nature, and are equally as relevant to human wellbeing as the identities of the interacting microbes. However, microbial interactions are difficult to measure and characterize. Furthermore, there is growing evidence that they are not fixed, but dependent on environmental context. We present a novel workflow for inferring microbial interactions that integrates semi-automated image analysis with a colony stamping mechanism, with the overall effect of improving throughput and reproducibility of colony interaction assays. We apply our approach to infer interactions among bacterial species associated with the normal lung microbiome, and how those interactions are altered by the presence of benzo[a]pyrene, a carcinogenic compound found in cigarettes. We found that the presence of this single compound changed the interaction network, demonstrating that microbial interactions are indeed dynamic and responsive to local chemical context.
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35
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Dreier J, Ruggerone P. Interaction of antibacterial compounds with RND efflux pumps in Pseudomonas aeruginosa. Front Microbiol 2015; 6:660. [PMID: 26217310 PMCID: PMC4495556 DOI: 10.3389/fmicb.2015.00660] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 06/16/2015] [Indexed: 01/14/2023] Open
Abstract
Pseudomonas aeruginosa infections are becoming increasingly difficult to treat due to intrinsic antibiotic resistance and the propensity of this pathogen to accumulate diverse resistance mechanisms. Hyperexpression of efflux pumps of the Resistance-Nodulation-Cell Division (RND)-type multidrug efflux pumps (e.g., MexAB-OprM), chromosomally encoded by mexAB-oprM, mexCD-oprJ, mexEF-oprN, and mexXY (-oprA) is often detected in clinical isolates and contributes to worrying multi-drug resistance phenotypes. Not all antibiotics are affected to the same extent by the aforementioned RND efflux pumps. The impact of efflux on antibiotic activity varies not only between different classes of antibiotics but also between members of the same family of antibiotics. Subtle differences in physicochemical features of compound-pump and compound-solvent interactions largely determine how compounds are affected by efflux activity. The combination of different high-resolution techniques helps to gain insight into the functioning of these molecular machineries. This review discusses substrate recognition patterns based on experimental evidence and computer simulations with a focus on MexB, the pump subunit of the main RND transporter in P. aeruginosa.
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Affiliation(s)
- Jürg Dreier
- Basilea Pharmaceutica International Ltd.,Basel, Switzerland
| | - Paolo Ruggerone
- Dipartimento di Fisica, Università di Cagliari – Cittadella UniversitariaMonserrato, Italy
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36
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Boyle KE, Monaco H, van Ditmarsch D, Deforet M, Xavier JB. Integration of Metabolic and Quorum Sensing Signals Governing the Decision to Cooperate in a Bacterial Social Trait. PLoS Comput Biol 2015; 11:e1004279. [PMID: 26102206 PMCID: PMC4477906 DOI: 10.1371/journal.pcbi.1004279] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 04/11/2015] [Indexed: 01/18/2023] Open
Abstract
Many unicellular organisms live in multicellular communities that rely on cooperation between cells. However, cooperative traits are vulnerable to exploitation by non-cooperators (cheaters). We expand our understanding of the molecular mechanisms that allow multicellular systems to remain robust in the face of cheating by dissecting the dynamic regulation of cooperative rhamnolipids required for swarming in Pseudomonas aeruginosa. We combine mathematical modeling and experiments to quantitatively characterize the integration of metabolic and population density signals (quorum sensing) governing expression of the rhamnolipid synthesis operon rhlAB. The combined computational/experimental analysis reveals that when nutrients are abundant, rhlAB promoter activity increases gradually in a density dependent way. When growth slows down due to nutrient limitation, rhlAB promoter activity can stop abruptly, decrease gradually or even increase depending on whether the growth-limiting nutrient is the carbon source, nitrogen source or iron. Starvation by specific nutrients drives growth on intracellular nutrient pools as well as the qualitative rhlAB promoter response, which itself is modulated by quorum sensing. Our quantitative analysis suggests a supply-driven activation that integrates metabolic prudence with quorum sensing in a non-digital manner and allows P. aeruginosa cells to invest in cooperation only when the population size is large enough (quorum sensing) and individual cells have enough metabolic resources to do so (metabolic prudence). Thus, the quantitative description of rhlAB regulatory dynamics brings a greater understating to the regulation required to make swarming cooperation stable. Although bacteria are not multicellular organisms, they commonly live in large communities and engage in many cooperative behaviors. Cooperation can allow bacteria to access additional nutrients, but it requires the secretion of products that will be shared by the community. How bacteria make the molecular decision to cooperate within a community is still not completely understood. The bacterium Pseudomonas aeruginosa regulates the secretion of one of these shared products, rhamnolipids, using information about population density and nutrient availability in its environment. Expression of the operon rhlAB is required for the bacteria to produce rhamnolipids. We use a combined computational and experimental approach to investigate how P. aeruginosa continually combines current information of population density and nutrient availability to determine if it should express rhlAB. We find that when conditions are nutrient rich, P. aeruginosa uses population density to modulate the amount rhlAB expression, however when the bacteria are starved for nutrients the starvation condition largely determines how the bacteria will express rhlAB. Because the bacteria continually adjust expression based on the current conditions, the molecular decision to produce rhamnolipids can be adjusted if either population density or nutrient conditions change. Our combined computational and experimental approach sheds new light on the rich regulatory dynamics that govern a cellular decision to cooperate.
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Affiliation(s)
- Kerry E. Boyle
- Program in Immunology and Microbial Pathogenesis, Weill Cornell Graduate School of Medical Sciences, New York, New York, United States of America
- Program in Computational Biology, Memorial Sloan Kettering Cancer Center, New York, New York, United States of America
| | - Hilary Monaco
- Program in Computational Biology, Memorial Sloan Kettering Cancer Center, New York, New York, United States of America
- Tri-Institutional Training Program in Computational Biology and Medicine, New York, New York, United States of America
| | - Dave van Ditmarsch
- Program in Computational Biology, Memorial Sloan Kettering Cancer Center, New York, New York, United States of America
| | - Maxime Deforet
- Program in Computational Biology, Memorial Sloan Kettering Cancer Center, New York, New York, United States of America
| | - Joao B. Xavier
- Program in Immunology and Microbial Pathogenesis, Weill Cornell Graduate School of Medical Sciences, New York, New York, United States of America
- Program in Computational Biology, Memorial Sloan Kettering Cancer Center, New York, New York, United States of America
- Tri-Institutional Training Program in Computational Biology and Medicine, New York, New York, United States of America
- * E-mail:
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37
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Morales-Soto N, Anyan ME, Mattingly AE, Madukoma CS, Harvey CW, Alber M, Déziel E, Kearns DB, Shrout JD. Preparation, imaging, and quantification of bacterial surface motility assays. J Vis Exp 2015. [PMID: 25938934 PMCID: PMC4541456 DOI: 10.3791/52338] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Bacterial surface motility, such as swarming, is commonly examined in the laboratory using plate assays that necessitate specific concentrations of agar and sometimes inclusion of specific nutrients in the growth medium. The preparation of such explicit media and surface growth conditions serves to provide the favorable conditions that allow not just bacterial growth but coordinated motility of bacteria over these surfaces within thin liquid films. Reproducibility of swarm plate and other surface motility plate assays can be a major challenge. Especially for more “temperate swarmers” that exhibit motility only within agar ranges of 0.4%-0.8% (wt/vol), minor changes in protocol or laboratory environment can greatly influence swarm assay results. “Wettability”, or water content at the liquid-solid-air interface of these plate assays, is often a key variable to be controlled. An additional challenge in assessing swarming is how to quantify observed differences between any two (or more) experiments. Here we detail a versatile two-phase protocol to prepare and image swarm assays. We include guidelines to circumvent the challenges commonly associated with swarm assay media preparation and quantification of data from these assays. We specifically demonstrate our method using bacteria that express fluorescent or bioluminescent genetic reporters like green fluorescent protein (GFP), luciferase (lux operon), or cellular stains to enable time-lapse optical imaging. We further demonstrate the ability of our method to track competing swarming species in the same experiment.
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Affiliation(s)
- Nydia Morales-Soto
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame; Eck Institute for Global Health, University of Notre Dame
| | - Morgen E Anyan
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame
| | - Anne E Mattingly
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame
| | - Chinedu S Madukoma
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame
| | - Cameron W Harvey
- Department of Applied and Computational Mathematics and Statistics, University of Notre Dame
| | - Mark Alber
- Department of Applied and Computational Mathematics and Statistics, University of Notre Dame
| | | | | | - Joshua D Shrout
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame; Eck Institute for Global Health, University of Notre Dame; Department of Biological Sciences, University of Notre Dame;
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38
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Anyan ME, Amiri A, Harvey CW, Tierra G, Morales-Soto N, Driscoll CM, Alber MS, Shrout JD. Type IV pili interactions promote intercellular association and moderate swarming of Pseudomonas aeruginosa. Proc Natl Acad Sci U S A 2014; 111:18013-8. [PMID: 25468980 PMCID: PMC4273417 DOI: 10.1073/pnas.1414661111] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Pseudomonas aeruginosa is a ubiquitous bacterium that survives in many environments, including as an acute and chronic pathogen in humans. Substantial evidence shows that P. aeruginosa behavior is affected by its motility, and appendages known as flagella and type IV pili (TFP) are known to confer such motility. The role these appendages play when not facilitating motility or attachment, however, is unclear. Here we discern a passive intercellular role of TFP during flagellar-mediated swarming of P. aeruginosa that does not require TFP extension or retraction. We studied swarming at the cellular level using a combination of laboratory experiments and computational simulations to explain the resultant patterns of cells imaged from in vitro swarms. Namely, we used a computational model to simulate swarming and to probe for individual cell behavior that cannot currently be otherwise measured. Our simulations showed that TFP of swarming P. aeruginosa should be distributed all over the cell and that TFP-TFP interactions between cells should be a dominant mechanism that promotes cell-cell interaction, limits lone cell movement, and slows swarm expansion. This predicted physical mechanism involving TFP was confirmed in vitro using pairwise mixtures of strains with and without TFP where cells without TFP separate from cells with TFP. While TFP slow swarm expansion, we show in vitro that TFP help alter collective motion to avoid toxic compounds such as the antibiotic carbenicillin. Thus, TFP physically affect P. aeruginosa swarming by actively promoting cell-cell association and directional collective motion within motile groups to aid their survival.
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Affiliation(s)
- Morgen E Anyan
- Departments of Civil and Environmental Engineering and Earth Sciences
| | | | | | - Giordano Tierra
- Applied and Computational Mathematics and Statistics, and Mathematical Institute, Charles University, 18675 Prague, Czech Republic; and
| | - Nydia Morales-Soto
- Departments of Civil and Environmental Engineering and Earth Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN 46556
| | - Callan M Driscoll
- Departments of Civil and Environmental Engineering and Earth Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN 46556
| | - Mark S Alber
- Physics, Applied and Computational Mathematics and Statistics, and Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202
| | - Joshua D Shrout
- Departments of Civil and Environmental Engineering and Earth Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN 46556; Biological Sciences, and
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39
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Cell division resets polarity and motility for the bacterium Myxococcus xanthus. J Bacteriol 2014; 196:3853-61. [PMID: 25157084 DOI: 10.1128/jb.02095-14] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Links between cell division and other cellular processes are poorly understood. It is difficult to simultaneously examine division and function in most cell types. Most of the research probing aspects of cell division has experimented with stationary or immobilized cells or distinctly asymmetrical cells. Here we took an alternative approach by examining cell division events within motile groups of cells growing on solid medium by time-lapse microscopy. A total of 558 cell divisions were identified among approximately 12,000 cells. We found an interconnection of division, motility, and polarity in the bacterium Myxococcus xanthus. For every division event, motile cells stop moving to divide. Progeny cells of binary fission subsequently move in opposing directions. This behavior involves M. xanthus Frz proteins that regulate M. xanthus motility reversals but is independent of type IV pilus "S motility." The inheritance of opposing polarity is correlated with the distribution of the G protein RomR within these dividing cells. The constriction at the point of division limits the intracellular distribution of RomR. Thus, the asymmetric distribution of RomR at the parent cell poles becomes mirrored at new poles initiated at the site of division.
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40
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Deforet M, van Ditmarsch D, Carmona-Fontaine C, Xavier JB. Hyperswarming adaptations in a bacterium improve collective motility without enhancing single cell motility. SOFT MATTER 2014; 10:2405-13. [PMID: 24622509 PMCID: PMC3955847 DOI: 10.1039/c3sm53127a] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Pseudomonas aeruginosa is a monoflagellated bacterium that can use its single polar flagellum to swim through liquids and move collectively over semisolid surfaces, a behavior called swarming. Previous studies have shown that experimental evolution in swarming colonies leads to the selection of hyperswarming bacteria with multiple flagella. Here we show that the advantage of such hyperswarmer mutants cannot be explained simply by an increase in the raw swimming speed of individual bacteria in liquids. Cell tracking of time-lapse microscopy to quantify single-cell swimming patterns reveals that both wild-type and hyperswarmers alternate between forward and backward runs, rather than doing the run-and-tumble characteristic of enteric bacteria such as E. coli. High-throughput measurement of swimming speeds reveals that hyperswarmers do not swim faster than wild-type in liquid. Wild-type reverses swimming direction in sharp turns without a significant impact on its speed, whereas multiflagellated hyperswarmers tend to alternate fast and slow runs and have wider turning angles. Nonetheless, macroscopic measurement of swimming and swarming speed in colonies shows that hyperswarmers expand faster than wild-type on surfaces and through soft agar matrices. A mathematical model explains how wider turning angles lead to faster spreading when swimming through agar. Our study describes for the first time the swimming patterns in multiflagellated P. aeruginosa mutants and reveals that collective and individual motility in bacteria are not necessarily correlated. Understanding bacterial adaptations to surface motility, such as hyperswarming, requires a collective behavior approach.
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Affiliation(s)
- Maxime Deforet
- Program in Computational Biology, Memorial Sloan-Kettering Cancer Center, New York, NY, USA.
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41
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Masyuko RN, Lanni EJ, Driscoll CM, Shrout JD, Sweedler JV, Bohn PW. Spatial organization of Pseudomonas aeruginosa biofilms probed by combined matrix-assisted laser desorption ionization mass spectrometry and confocal Raman microscopy. Analyst 2014; 139:5700-8. [DOI: 10.1039/c4an00435c] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The chemical composition of bacterial biofilms is explored and visualized with the combination of two label-free molecular imaging techniques.
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Affiliation(s)
- Rachel N. Masyuko
- Department of Chemistry and Biochemistry
- University of Notre Dame
- Notre Dame, USA
| | - Eric J. Lanni
- Department of Chemistry
- University of Illinois at Urbana-Champaign
- Urbana, USA
| | - Callan M. Driscoll
- Department of Civil and Environmental Engineering and Earth Sciences
- University of Notre Dame
- Notre Dame, USA
| | - Joshua D. Shrout
- Department of Civil and Environmental Engineering and Earth Sciences
- University of Notre Dame
- Notre Dame, USA
| | | | - Paul W. Bohn
- Department of Chemistry and Biochemistry
- University of Notre Dame
- Notre Dame, USA
- Department of Chemical and Biomolecular Engineering
- University of Notre Dame
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42
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Neu TR, Lawrence JR. Investigation of microbial biofilm structure by laser scanning microscopy. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2014; 146:1-51. [PMID: 24840778 DOI: 10.1007/10_2014_272] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Microbial bioaggregates and biofilms are hydrated three-dimensional structures of cells and extracellular polymeric substances (EPS). Microbial communities associated with interfaces and the samples thereof may come from natural, technical, and medical habitats. For imaging such complex microbial communities confocal laser scanning microscopy (CLSM) is the method of choice. CLSM allows flexible mounting and noninvasive three-dimensional sectioning of hydrated, living, as well as fixed samples. For this purpose a broad range of objective lenses is available having different working distance and resolution. By means of CLSM the signals detected may originate from reflection, autofluorescence, reporter genes/fluorescence proteins, fluorochromes binding to specific targets, or other probes conjugated with fluorochromes. Recorded datasets can be used not only for visualization but also for semiquantitative analysis. As a result CLSM represents a very useful tool for imaging of microbiological samples in combination with other analytical techniques.
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Affiliation(s)
- Thomas R Neu
- Department of River Ecology, Helmholtz Centre for Environmental Research-UFZ, Brueckstrasse 3a, 39114, Magdeburg, Germany,
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43
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van Ditmarsch D, Boyle KE, Sakhtah H, Oyler JE, Nadell CD, Déziel É, Dietrich LEP, Xavier JB. Convergent evolution of hyperswarming leads to impaired biofilm formation in pathogenic bacteria. Cell Rep 2013; 4:697-708. [PMID: 23954787 DOI: 10.1016/j.celrep.2013.07.026] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 07/01/2013] [Accepted: 07/24/2013] [Indexed: 12/16/2022] Open
Abstract
Most bacteria in nature live in surface-associated communities rather than planktonic populations. Nonetheless, how surface-associated environments shape bacterial evolutionary adaptation remains poorly understood. Here, we show that subjecting Pseudomonas aeruginosa to repeated rounds of swarming, a collective form of surface migration, drives remarkable parallel evolution toward a hyperswarmer phenotype. In all independently evolved hyperswarmers, the reproducible hyperswarming phenotype is caused by parallel point mutations in a flagellar synthesis regulator, FleN, which locks the naturally monoflagellated bacteria in a multiflagellated state and confers a growth rate-independent advantage in swarming. Although hyperswarmers outcompete the ancestral strain in swarming competitions, they are strongly outcompeted in biofilm formation, which is an essential trait for P. aeruginosa in environmental and clinical settings. The finding that evolution in swarming colonies reliably produces evolution of poor biofilm formers supports the existence of an evolutionary trade-off between motility and biofilm formation.
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Affiliation(s)
- Dave van Ditmarsch
- Program in Computational Biology, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
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44
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Manos J, Hu H, Rose BR, Wainwright CE, Zablotska IB, Cheney J, Turnbull L, Whitchurch CB, Grimwood K, Harmer C, Anuj SN, Harbour C. Virulence factor expression patterns in Pseudomonas aeruginosa strains from infants with cystic fibrosis. Eur J Clin Microbiol Infect Dis 2013; 32:1583-92. [DOI: 10.1007/s10096-013-1916-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Accepted: 06/17/2013] [Indexed: 12/16/2022]
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45
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Du H, Xu Z, Anyan M, Kim O, Leevy WM, Shrout JD, Alber M. High density waves of the bacterium Pseudomonas aeruginosa in propagating swarms result in efficient colonization of surfaces. Biophys J 2013; 103:601-609. [PMID: 22947877 DOI: 10.1016/j.bpj.2012.06.035] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Revised: 06/04/2012] [Accepted: 06/19/2012] [Indexed: 02/05/2023] Open
Abstract
This work describes a new, to our knowledge, strategy of efficient colonization and community development where bacteria substantially alter their physical environment. Many bacteria move in groups, in a mode described as swarming, to colonize surfaces and form biofilms to survive external stresses, including exposure to antibiotics. One such bacterium is Pseudomonas aeruginosa, which is an opportunistic pathogen responsible for both acute and persistent infections in susceptible individuals, as exampled by those for burn victims and people with cystic fibrosis. Pseudomonas aeruginosa often, but not always, forms branched tendril patterns during swarming; this phenomena occurs only when bacteria produce rhamnolipid, which is regulated by population-dependent signaling called quorum sensing. The experimental results of this work show that P. aeruginosa cells propagate as high density waves that move symmetrically as rings within swarms toward the extending tendrils. Biologically justified cell-based multiscale model simulations suggest a mechanism of wave propagation as well as a branched tendril formation at the edge of the population that depends upon competition between the changing viscosity of the bacterial liquid suspension and the liquid film boundary expansion caused by Marangoni forces. Therefore, P. aeruginosa efficiently colonizes surfaces by controlling the physical forces responsible for expansion of thin liquid film and by propagating toward the tendril tips. The model predictions of wave speed and swarm expansion rate as well as cell alignment in tendrils were confirmed experimentally. The study results suggest that P. aeruginosa responds to environmental cues on a very short timescale by actively exploiting local physical phenomena to develop communities and efficiently colonize new surfaces.
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Affiliation(s)
- Huijing Du
- Department of Applied and Computational Mathematics and Statistics, University of Notre Dame, Notre Dame, Indiana
| | - Zhiliang Xu
- Department of Applied and Computational Mathematics and Statistics, University of Notre Dame, Notre Dame, Indiana
| | - Morgen Anyan
- Department of Civil Engineering and Geological Sciences, University of Notre Dame, Notre Dame, Indiana
| | - Oleg Kim
- Department of Applied and Computational Mathematics and Statistics, University of Notre Dame, Notre Dame, Indiana
| | - W Matthew Leevy
- Notre Dame Integrated Imaging Facility, University of Notre Dame, Notre Dame, Indiana; Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana
| | - Joshua D Shrout
- Department of Civil Engineering and Geological Sciences, University of Notre Dame, Notre Dame, Indiana; Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana; Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana
| | - Mark Alber
- Department of Applied and Computational Mathematics and Statistics, University of Notre Dame, Notre Dame, Indiana; Department of Medicine, Indiana University School of Medicine, Indiana.
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46
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Kamatkar NG, Sarna MJ, Shrout JD. Population dynamics during swarming of Pseudomonas aeruginosa. Commun Integr Biol 2011; 4:689-91. [PMID: 22446528 DOI: 10.4161/cib.17109] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Swarming is a group motility behavior exhibited by bacteria that coordinate to spread over surfaces. Swarms of the bacterium Pseudomonas aeruginosa often develop tendril patterns and tendril development requires production of the surfactant rhamnolipid. We recently showed that harder surfaces limit induction of quorum sensing genes including those responsible for rhamnolipid synthesis, but it is not yet clear why similar populations of cells should behave differently on hard surfaces compared with soft (agar) surfaces. Here we explore the population dynamics during P. aeruginosa swarming. We find that the population of P. aeruginosa does not immediately increase as the swarm expands. We also detail three stages of population development during swarming.
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