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Rijal R, Gomer RH. Proteomic Analysis of Dictyostelium discoideum by Mass Spectrometry. Methods Mol Biol 2024; 2814:247-255. [PMID: 38954210 DOI: 10.1007/978-1-0716-3894-1_17] [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] [Indexed: 07/04/2024]
Abstract
The large-scale proteomic analysis of Dictyostelium discoideum has contributed to our understanding of intracellular as well as secreted proteins in this versatile model eukaryote. Mass spectrometry-based proteomic analysis is a robust, sensitive, and rapid analytical method for identification and characterization of proteins extracted from tissues, cells, cell fractions, or pull-down assays. The availability of core facilities which make proteomics inexpensive and easy to do has facilitated a wide range of research projects. In this chapter, we present a simple standard methodology to extract proteins and prepare samples from D. discoideum for mass spectrometry and methods to analyze the identified proteins.
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Affiliation(s)
- Ramesh Rijal
- Department of Biology, Texas A&M University, College Station, TX, USA
| | - Richard H Gomer
- Department of Biology, Texas A&M University, College Station, TX, USA.
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2
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Touré H, Herrmann JL, Szuplewski S, Girard-Misguich F. Drosophila melanogaster as an organism model for studying cystic fibrosis and its major associated microbial infections. Infect Immun 2023; 91:e0024023. [PMID: 37847031 PMCID: PMC10652941 DOI: 10.1128/iai.00240-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2023] Open
Abstract
Cystic fibrosis (CF) is a human genetic disease caused by mutations in the cystic fibrosis transmembrane conductance regulator gene that encodes a chloride channel. The most severe clinical manifestation is associated with chronic pulmonary infections by pathogenic and opportunistic microbes. Drosophila melanogaster has become the invertebrate model of choice for modeling microbial infections and studying the induced innate immune response. Here, we review its contribution to the understanding of infections with six major pathogens associated with CF (Staphylococcus aureus, Pseudomonas aeruginosa, Burkholderia cepacia, Mycobacterium abscessus, Streptococcus pneumoniae, and Aspergillus fumigatus) together with the perspectives opened by the recent availability of two CF models in this model organism.
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Affiliation(s)
- Hamadoun Touré
- Université Paris-Saclay, UVSQ, INSERM, Infection et Inflammation, Montigny-le-Bretonneux, France
| | - Jean-Louis Herrmann
- Université Paris-Saclay, UVSQ, INSERM, Infection et Inflammation, Montigny-le-Bretonneux, France
- Assistance Publique-Hôpitaux de Paris, Hôpitaux Universitaires Ile-de-France Ouest, GHU Paris-Saclay, Hôpital Raymond Poincaré, Garches, France
| | - Sébastien Szuplewski
- Université Paris-Saclay, UVSQ, Laboratoire de Génétique et Biologie Cellulaire, Montigny-le-Bretonneux, France
| | - Fabienne Girard-Misguich
- Université Paris-Saclay, UVSQ, INSERM, Infection et Inflammation, Montigny-le-Bretonneux, France
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3
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Presence of the Hmq System and Production of 4-Hydroxy-3-Methyl-2-Alkylquinolines Are Heterogeneously Distributed between Burkholderia cepacia Complex Species and More Prevalent among Environmental than Clinical Isolates. Microbiol Spectr 2021; 9:e0012721. [PMID: 34132614 PMCID: PMC8552760 DOI: 10.1128/spectrum.00127-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The Burkholderia cepacia complex (Bcc) comprises several species of closely related, versatile bacteria. Some Bcc strains produce 4-hydroxy-3-methyl-2-alkylquinolines (HMAQs), analogous to the 4-hydroxy-2-alkylquinolines of Pseudomonas aeruginosa. Using in silico analyses, we previously estimated that the hmqABCDEFG operon, which encodes enzymes involved in the biosynthesis of HMAQs, is carried by about one-third of Bcc strains, with considerable inter- and intraspecies variability. In the present study, we investigated by PCR, using consensus primers, the distribution of hmqABCDEFG in a collection of 312 Bcc strains (222 of clinical and 90 of environmental origins) belonging to 18 Bcc species. We confirmed that this operon is not distributed evenly among Bcc species. Among the 30% of strains bearing the hmqABCDEFG operon, we found that 92% of environmental isolates and 82% of clinically isolated Bcc strains produce levels of HMAQs detectable by liquid chromatography-mass spectrometry in at least one of the tested culture conditions. Among the hmqABCDEFG-positive but HMAQ-negative strains, none expressed the hmqA gene under the specified culture conditions. Interestingly, the hmqABCDEFG operon is more prevalent among plant root environment species (e.g., Burkholderia ambifaria and Burkholderia cepacia) and absent in species commonly found in chronically colonized individuals with cystic fibrosis (e.g., Burkholderia cenocepacia and Burkholderia multivorans), suggesting a role for the Hmq system in niche adaptation. We investigated the impact of the Hmq system on plant growth promotion and found that Pisum sativum root development by B. ambifaria required a functional HMAQ system. IMPORTANCE Environmental bacteria belonging to the various closely related species forming the Burkholderia cepacia complex (Bcc) can infect plants and animals, including humans. Their pathogenicity is regulated by intercellular communication, or quorum sensing, allowing them to collaborate instead of acting individually. Bcc organisms generally exploit interacting quorum sensing systems based on N-acyl-homoserine lactones as signaling molecules. Several Bcc strains also carry an hmqABCDEFG operon responsible for the biosynthesis of 4-hydroxy-3-methyl-2-alkylquinolines (HMAQs), molecules analogous to the Pseudomonas quinolone signal (PQS) system of P. aeruginosa. Our finding that the prevalences of the Hmq system and HMAQ production are very different between various Bcc species suggests a key role in niche adaptation or pathogenicity. This is supported by a significant reduction in plant growth promotion in the absence of HMAQ production for a beneficial Bcc strain.
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4
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Prothiwa M, Filz V, Oehler S, Böttcher T. Inhibiting quinolone biosynthesis of Burkholderia. Chem Sci 2021; 12:6908-6912. [PMID: 34123319 PMCID: PMC8153077 DOI: 10.1039/d0sc06167k] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
2-Alkylquinolones are important signalling molecules of Burkholderia species. We developed a substrate-based chemical probe against the central quinolone biosynthesis enzyme HmqD and applied it in competitive profiling experiments to discover the first known HmqD inhibitors. The most potent inhibitors quantitatively blocked quinolone production in Burkholderia cultures with single-digit micromolar efficacy.
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Affiliation(s)
- Michaela Prothiwa
- Department of Chemistry, Konstanz Research School Chemical Biology, University of Konstanz 78457 Konstanz Germany
| | - Verena Filz
- Department of Chemistry, Konstanz Research School Chemical Biology, University of Konstanz 78457 Konstanz Germany.,Faculty of Chemistry, Department of Biological Chemistry & Centre for Microbiology and Environmental Systems Science, Division of Microbial Ecology, University of Vienna 1090 Vienna Austria
| | - Sebastian Oehler
- Department of Chemistry, Konstanz Research School Chemical Biology, University of Konstanz 78457 Konstanz Germany
| | - Thomas Böttcher
- Department of Chemistry, Konstanz Research School Chemical Biology, University of Konstanz 78457 Konstanz Germany.,Faculty of Chemistry, Department of Biological Chemistry & Centre for Microbiology and Environmental Systems Science, Division of Microbial Ecology, University of Vienna 1090 Vienna Austria
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5
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Bonkowski M, Tarkka M, Razavi BS, Schmidt H, Blagodatskaya E, Koller R, Yu P, Knief C, Hochholdinger F, Vetterlein D. Spatiotemporal Dynamics of Maize ( Zea mays L.) Root Growth and Its Potential Consequences for the Assembly of the Rhizosphere Microbiota. Front Microbiol 2021; 12:619499. [PMID: 33815308 PMCID: PMC8010349 DOI: 10.3389/fmicb.2021.619499] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 02/16/2021] [Indexed: 12/20/2022] Open
Abstract
Numerous studies have shown that plants selectively recruit microbes from the soil to establish a complex, yet stable and quite predictable microbial community on their roots – their “microbiome.” Microbiome assembly is considered as a key process in the self-organization of root systems. A fundamental question for understanding plant-microbe relationships is where a predictable microbiome is formed along the root axis and through which microbial dynamics the stable formation of a microbiome is challenged. Using maize as a model species for which numerous data on dynamic root traits are available, this mini-review aims to give an integrative overview on the dynamic nature of root growth and its consequences for microbiome assembly based on theoretical considerations from microbial community ecology.
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Affiliation(s)
- Michael Bonkowski
- Terrestrial Ecology, Institute of Zoology, University of Cologne, Cologne, Germany
| | - Mika Tarkka
- Department of Soil Ecology, Helmholtz Centre for Environmental Research - UFZ, Halle, Germany.,German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany
| | - Bahar S Razavi
- Department of Soil and Plant Microbiome, Christian-Albrecht University of Kiel, Kiel, Germany
| | - Hannes Schmidt
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - Evgenia Blagodatskaya
- Department of Soil Ecology, Helmholtz Centre for Environmental Research - UFZ, Halle, Germany
| | - Robert Koller
- Institute of Bio- and Geosciences, IBG-2: Plant Sciences, Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Peng Yu
- Emmy Noether Group Root Functional Biology, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Bonn, Germany
| | - Claudia Knief
- Institute of Crop Science and Resource Conservation - Molecular Biology of the Rhizosphere, University of Bonn, Bonn, Germany
| | - Frank Hochholdinger
- Crop Functional Genomics, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Bonn, Germany
| | - Doris Vetterlein
- Department of Soil System Science, Helmholtz Centre for Environmental Research - UFZ, Halle, Germany.,Soil Science, Martin-Luther-University Halle-Wittenberg, Halle, Germany
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6
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Lee Y, Kim YS, Balaraju K, Seo YS, Park J, Ryu CM, Park SH, Kim JF, Kang S, Jeon Y. Molecular changes associated with spontaneous phenotypic variation of Paenibacillus polymyxa, a commonly used biocontrol agent, and temperature-dependent control of variation. Sci Rep 2020; 10:16586. [PMID: 33024195 PMCID: PMC7538429 DOI: 10.1038/s41598-020-73716-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 09/21/2020] [Indexed: 11/19/2022] Open
Abstract
There has been a growing interest in deploying plant growth-promoting rhizobacteria (PGPR) as a biological control agent (BCA) to reduce the use of agrochemicals. Spontaneous phenotypic variation of PGPR, which causes the loss of traits crucial for biocontrol, presents a large obstacle in producing commercial biocontrol products. Here, we report molecular changes associated with phenotypic variation in Paenibacillus polymyxa, a PGPR widely used for biocontrol worldwide, and a simple cultural change that can prevent the variation. Compared to B-type (non-variant) cells of P. polymyxa strain E681, its phenotypic variant, termed as F-type, fails to form spores, does not confer plant growth-promoting effect, and displays altered colony and cell morphology, motility, antagonism against other microbes, and biofilm formation. This variation was observed in all tested strains of P. polymyxa, but the frequency varied among them. RNA-seq analysis revealed differential regulation of many genes involved in sporulation, flagella synthesis, carbohydrate metabolism, and antimicrobial production in F-type cells, consistent with their pleiotropic phenotypic changes. F-type cells's sporulation was arrested at stage 0, and the key sporulation gene spo0A was upregulated only in B-type cells. The phenotypic variation could be prevented by altering the temperature for growth. When E681 was cultured at 20 °C or lower, it exhibited no variation for 7 days and still reached ~ 108 cfu/mL, the level sufficient for commercial-scale production of biocontrol products.
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Affiliation(s)
- Younmi Lee
- Department of Plant Medicals, Andong National University, Andong, 36729, Republic of Korea.,Agricultural Science and Technology Research Institute, Andong National University, Andong, 36729, Republic of Korea
| | - Young Soo Kim
- Department of Plant Medicals, Andong National University, Andong, 36729, Republic of Korea
| | - Kotnala Balaraju
- Agricultural Science and Technology Research Institute, Andong National University, Andong, 36729, Republic of Korea
| | - Young-Su Seo
- Department of Microbiology, Pusan National University, Pusan, 46241, Republic of Korea
| | - Jungwook Park
- Department of Microbiology, Pusan National University, Pusan, 46241, Republic of Korea
| | - Choong-Min Ryu
- Infectious Disease Research Centre, KRIBB, Daejeon, 34141, Republic of Korea.,Department of Biosystems and Bioengineering, KRIBB School of Biotechnology, Korea University of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Seung-Hwan Park
- Infectious Disease Research Centre, KRIBB, Daejeon, 34141, Republic of Korea.,Department of Biosystems and Bioengineering, KRIBB School of Biotechnology, Korea University of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Jihyun F Kim
- Department of Systems Biology, Division of Life Sciences, and Institute for Life Science and Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea.,Strategic Initiative for Microbiomes in Agriculture and Food (iMAF), Yonsei University, Seoul, 03722, Republic of Korea
| | - Seogchan Kang
- Department of Plant Pathology and Environmental Microbiology, Pennsylvania State University, University Park, PA, 16802, USA
| | - Yongho Jeon
- Department of Plant Medicals, Andong National University, Andong, 36729, Republic of Korea.
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7
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Biofilm-Constructing Variants of Paraburkholderia phytofirmans PsJN Outcompete the Wild-Type Form in Free-Living and Static Conditions but Not In Planta. Appl Environ Microbiol 2019; 85:AEM.02670-18. [PMID: 30902863 DOI: 10.1128/aem.02670-18] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 03/09/2019] [Indexed: 11/20/2022] Open
Abstract
Members of the genus Burkholderia colonize diverse ecological niches. Among the plant-associated strains, Paraburkholderia phytofirmans PsJN is an endophyte with a broad host range. In a spatially structured environment (unshaken broth cultures), biofilm-constructing specialists of P. phytofirmans PsJN colonizing the air-liquid interface arose at high frequency. In addition to forming a robust biofilm in vitro and in planta on Arabidopsis roots, those mucoid phenotypic variants display a reduced swimming ability and modulate the expression of several microbe-associated molecular patterns (MAMPs), including exopolysaccharides (EPS), flagellin, and GroEL. Interestingly, the variants induce low PR1 and PDF1.2 expression compared to that of the parental strain, suggesting a possible evasion of plant host immunity. We further demonstrated that switching from the planktonic to the sessile form did not involve quorum-sensing genes but arose from spontaneous mutations in two genes belonging to an iron-sulfur cluster: hscA (encoding a cochaperone protein) and iscS (encoding a cysteine desulfurase). A mutational approach validated the implication of these two genes in the appearance of variants. We showed for the first time that in a heterogeneous environment, P. phytofirmans strain PsJN is able to rapidly diversify and coexpress a variant that outcompete the wild-type form in free-living and static conditions but not in planta IMPORTANCE Paraburkholderia phytofirmans strain PsJN is a well-studied plant-associated bacterium known to induce resistance against biotic and abiotic stresses. In this work, we described the spontaneous appearance of mucoid variants in PsJN from static cultures. We showed that the conversion from the wild-type (WT) form to variants (V) correlates with an overproduction of EPS, an enhanced ability to form biofilm in vitro and in planta, and a reduced swimming motility. Our results revealed also that these phenotypes are in part associated with spontaneous mutations in an iron-sulfur cluster. Overall, the data provided here allow a better understanding of the adaptive mechanisms likely developed by P. phytofirmans PsJN in a heterogeneous environment.
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8
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Behren S, Westerlind U. Glycopeptides and -Mimetics to Detect, Monitor and Inhibit Bacterial and Viral Infections: Recent Advances and Perspectives. Molecules 2019; 24:E1004. [PMID: 30871155 PMCID: PMC6471658 DOI: 10.3390/molecules24061004] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 03/06/2019] [Accepted: 03/07/2019] [Indexed: 11/17/2022] Open
Abstract
The initial contact of pathogens with host cells is usually mediated by their adhesion to glycan structures present on the cell surface in order to enable infection. Furthermore, glycans play important roles in the modulation of the host immune responses to infection. Understanding the carbohydrate-pathogen interactions are of importance for the development of novel and efficient strategies to either prevent, or interfere with pathogenic infection. Synthetic glycopeptides and mimetics thereof are capable of imitating the multivalent display of carbohydrates at the cell surface, which have become an important objective of research over the last decade. Glycopeptide based constructs may function as vaccines or anti-adhesive agents that interfere with the ability of pathogens to adhere to the host cell glycans and thus possess the potential to improve or replace treatments that suffer from resistance. Additionally, synthetic glycopeptides are used as tools for epitope mapping of antibodies directed against structures present on various pathogens and have become important to improve serodiagnostic methods and to develop novel epitope-based vaccines. This review will provide an overview of the most recent advances in the synthesis and application of glycopeptides and glycopeptide mimetics exhibiting a peptide-like backbone in glycobiology.
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Affiliation(s)
- Sandra Behren
- Department of Chemistry, Umeå University, 90187 Umeå, Sweden.
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9
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Coulon PML, Groleau MC, Déziel E. Potential of the Burkholderia cepacia Complex to Produce 4-Hydroxy-3-Methyl-2-Alkyquinolines. Front Cell Infect Microbiol 2019; 9:33. [PMID: 30873388 PMCID: PMC6403149 DOI: 10.3389/fcimb.2019.00033] [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: 11/16/2018] [Accepted: 02/01/2019] [Indexed: 12/22/2022] Open
Abstract
A few Burkholderia species, especially Burkholderia pseudomallei, Burkholderia thailandensis, Burkholderia ambifaria, and Burkholderia cepacia, are known to produce and release various 4-hydroxy-3-methyl-2-alkylquinolines (HMAQs), a family of molecules analogous to the 4-hydroxy-2-alkylquinolines [aka 2-n-alkyl-4(1H)-quinolones] of Pseudomonas aeruginosa, which include the Pseudomonas quinolone signal (PQS). However, while these exoproducts play several roles in P. aeruginosa virulence and survival, the available literature is very limited on their distribution and function in Burkholderia. In this perspective article, we studied the distribution of the hmqABCDEFG operon, which encodes the enzymes involved in the biosynthesis of HMAQs, in the Burkholderia cepacia complex (Bcc) group. Based on the available sequence data, about one third of Bcc species carry a homolog of the hmqABCDEFG, and not all sequenced strains in a given species possess this operon. Looking at the synteny of genes surrounding the hmqABCDEFG operon, we found that for some species, the operon seems to have been deleted or replaced by other genes. Finally, we review the literature on the possible function of HMAQs. Understanding the Hmq system may provide clues concerning their functions in Bcc.
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Affiliation(s)
- Pauline M L Coulon
- Institut Armand Frappier, Institut National de la Recherche Scientifique, Laval, QC, Canada
| | | | - Eric Déziel
- Institut Armand Frappier, Institut National de la Recherche Scientifique, Laval, QC, Canada
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10
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DeShazer D, Lovett S, Richardson J, Koroleva G, Kuehl K, Amemiya K, Sun M, Worsham P, Welkos S. Bacteriophage-associated genes responsible for the widely divergent phenotypes of variants of Burkholderia pseudomallei strain MSHR5848. J Med Microbiol 2019; 68:263-278. [PMID: 30628877 DOI: 10.1099/jmm.0.000908] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
PURPOSE Burkholderia pseudomallei, the tier 1 agent of melioidosis, is a saprophytic microbe that causes endemic infections in tropical regions such as South-East Asia and Northern Australia. It is globally distributed, challenging to diagnose and treat, infectious by several routes including inhalation, and has potential for adversarial use. B. pseudomallei strain MSHR5848 produces two colony variants, smooth (S) and rough (R), which exhibit a divergent range of morphological, biochemical and metabolic phenotypes, and differ in macrophage and animal infectivity. We aimed to characterize two major phenotypic differences, analyse gene expression and study the regulatory basis of the variation. METHODOLOGY Phenotypic expression was characterized by DNA and RNA sequencing, microscopy, and differential bacteriology. Regulatory genes were identified by cloning and bioinformatics.Results/Key findings. Whereas S produced larger quantities of extracellular DNA, R was upregulated in the production of a unique chromosome 1-encoded Siphoviridae-like bacteriophage, φMSHR5848. Exploratory transcriptional analyses revealed significant differences in variant expression of genes encoding siderophores, pili assembly, type VI secretion system cluster 4 (T6SS-4) proteins, several exopolysaccharides and secondary metabolites. A single 3 base duplication in S was the only difference that separated the variants genetically. It occurred upstream of a cluster of bacteriophage-associated genes on chromosome 2 that were upregulated in S. The first two genes were involved in regulating expression of the multiple phenotypes distinguishing S and R. CONCLUSION Bacteriophage-associated proteins have a major role in the phenotypic expression of MSHR5848. The goals are to determine the regulatory basis of this phenotypic variation and its role in pathogenesis and environmental persistence of B. pseudomallei.
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Affiliation(s)
- David DeShazer
- 1Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD, USA
| | - Sean Lovett
- 2Center for Genome Sciences, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD, USA
| | - Joshua Richardson
- 2Center for Genome Sciences, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD, USA
| | - Galina Koroleva
- 2Center for Genome Sciences, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD, USA.,†Present address: Room 7N109, Center for Human Immunology, Autoimmunity and Inflammation, National Institute of Allergy and Infectious Diseases, 10 Center Drive, Bethesda, MD 20814, USA
| | - Kathleen Kuehl
- 3Pathology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD, USA
| | - Kei Amemiya
- 1Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD, USA
| | - Mei Sun
- 4United States Army Medical Research and Materiel Command (USAMRMC), Frederick, MD, USA
| | - Patricia Worsham
- 1Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD, USA
| | - Susan Welkos
- 1Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD, USA
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11
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Chapalain A, Groleau MC, Le Guillouzer S, Miomandre A, Vial L, Milot S, Déziel E. Interplay between 4-Hydroxy-3-Methyl-2-Alkylquinoline and N-Acyl-Homoserine Lactone Signaling in a Burkholderia cepacia Complex Clinical Strain. Front Microbiol 2017; 8:1021. [PMID: 28676791 PMCID: PMC5476693 DOI: 10.3389/fmicb.2017.01021] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 05/22/2017] [Indexed: 11/13/2022] Open
Abstract
Species from the Burkholderia cepacia complex (Bcc) share a canonical LuxI/LuxR quorum sensing (QS) regulation system named CepI/CepR, which mainly relies on the acyl-homoserine lactone (AHL), octanoyl-homoserine lactone (C8-HSL) as signaling molecule. Burkholderia ambifaria is one of the least virulent Bcc species, more often isolated from rhizospheres where it exerts a plant growth-promoting activity. However, clinical strains of B. ambifaria display distinct features, such as phase variation and higher virulence properties. Notably, we previously reported that under laboratory conditions, only clinical strains of the B. ambifaria species produced 4-hydroxy-3-methyl-2-alkylquinolines (HMAQs) via expression of the hmqABCDEFG operon. HMAQs are the methylated counterparts of the 4-hydroxy-2-alkylquinolines (HAQs) produced by the opportunistic human pathogen Pseudomonas aeruginosa, in which they globally contribute to the bacterial virulence and survival. We have found that unlike P. aeruginosa's HAQs, HMAQs do not induce their own production. However, they indirectly regulate the expression of the hmqABCDEFG operon. In B. ambifaria, a strong link between CepI/CepR-based QS and HMAQs is proposed, as we have previously reported an increased production of C8-HSL in HMAQ-negative mutants. Here, we report the identification of all AHLs produced by the clinical B. ambifaria strain HSJ1, namely C6-HSL, C8-HSL, C10-HSL, 3OHC8-HSL, 3OHC10-HSL, and 3OHC12-HSL. Production of significant levels of hydroxylated AHLs prompted the identification of a second complete LuxI/LuxR-type QS system relying on 3OHC10-HSL and 3OHC12-HSL, that we have named CepI2/CepR2. The connection between these two QS systems and the hmqABCDEFG operon, responsible for HMAQs biosynthesis, was investigated. The CepI/CepR system strongly induced the operon, while the second system appears moderately involved. On the other hand, a HMAQ-negative mutant overproduces AHLs from both QS systems. Even if HMAQs are not classical QS signals, their effect on AHL-based QS system still gives them a part to play in the QS circuitry in B. ambifaria and thus, on regulation of various phenotypes.
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Affiliation(s)
- Annelise Chapalain
- CIRI, Centre International de Recherche en Infectiologie, Equipe Pathogénèse des Légionelles, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, École Normale Supérieure de Lyon, Université LyonLyon, France
| | | | | | - Aurélie Miomandre
- CNRS, INRA, UMR 5557, Ecologie Microbienne, Université Lyon 1Villeurbanne, France
| | - Ludovic Vial
- CNRS, INRA, UMR 5557, Ecologie Microbienne, Université Lyon 1Villeurbanne, France
| | | | - Eric Déziel
- INRS-Institut Armand-Frappier, LavalQC, Canada
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12
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Shea AA, Bernhards RC, Cote CK, Chase CJ, Koehler JW, Klimko CP, Ladner JT, Rozak DA, Wolcott MJ, Fetterer DP, Kern SJ, Koroleva GI, Lovett SP, Palacios GF, Toothman RG, Bozue JA, Worsham PL, Welkos SL. Two stable variants of Burkholderia pseudomallei strain MSHR5848 express broadly divergent in vitro phenotypes associated with their virulence differences. PLoS One 2017; 12:e0171363. [PMID: 28187198 PMCID: PMC5302386 DOI: 10.1371/journal.pone.0171363] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 01/18/2017] [Indexed: 12/12/2022] Open
Abstract
Burkholderia pseudomallei (Bp), the agent of melioidosis, causes disease ranging from acute and rapidly fatal to protracted and chronic. Bp is highly infectious by aerosol, can cause severe disease with nonspecific symptoms, and is naturally resistant to multiple antibiotics. However, no vaccine exists. Unlike many Bp strains, which exhibit random variability in traits such as colony morphology, Bp strain MSHR5848 exhibited two distinct and relatively stable colony morphologies on sheep blood agar plates: a smooth, glossy, pale yellow colony and a flat, rough, white colony. Passage of the two variants, designated "Smooth" and "Rough", under standard laboratory conditions produced cultures composed of > 99.9% of the single corresponding type; however, both could switch to the other type at different frequencies when incubated in certain nutritionally stringent or stressful growth conditions. These MSHR5848 derivatives were extensively characterized to identify variant-associated differences. Microscopic and colony morphology differences on six differential media were observed and only the Rough variant metabolized sugars in selective agar. Antimicrobial susceptibilities and lipopolysaccharide (LPS) features were characterized and phenotype microarray profiles revealed distinct metabolic and susceptibility disparities between the variants. Results using the phenotype microarray system narrowed the 1,920 substrates to a subset which differentiated the two variants. Smooth grew more rapidly in vitro than Rough, yet the latter exhibited a nearly 10-fold lower lethal dose for mice than Smooth. Finally, the Smooth variant was phagocytosed and replicated to a greater extent and was more cytotoxic than Rough in macrophages. In contrast, multiple locus sequence type (MLST) analysis, ribotyping, and whole genome sequence analysis demonstrated the variants' genetic conservation; only a single consistent genetic difference between the two was identified for further study. These distinct differences shown by two variants of a Bp strain will be leveraged to better understand the mechanism of Bp phenotypic variability and to possibly identify in vitro markers of infection.
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Affiliation(s)
- A. A. Shea
- Diagnostic Systems Division, USAMRIID, Frederick, Maryland, United States of America
| | - R. C. Bernhards
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, Maryland, United States of America
| | - C. K. Cote
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, Maryland, United States of America
| | - C. J. Chase
- Diagnostic Systems Division, USAMRIID, Frederick, Maryland, United States of America
| | - J. W. Koehler
- Diagnostic Systems Division, USAMRIID, Frederick, Maryland, United States of America
| | - C. P. Klimko
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, Maryland, United States of America
| | - J. T. Ladner
- Center for Genome Sciences, USAMRIID, Frederick, Maryland, United States of America
| | - D. A. Rozak
- Diagnostic Systems Division, USAMRIID, Frederick, Maryland, United States of America
| | - M. J. Wolcott
- Diagnostic Systems Division, USAMRIID, Frederick, Maryland, United States of America
| | - D. P. Fetterer
- Biostatistical Services Division, USAMRIID, Frederick, Maryland, United States of America
| | - S. J. Kern
- Biostatistical Services Division, USAMRIID, Frederick, Maryland, United States of America
| | - G. I. Koroleva
- Center for Genome Sciences, USAMRIID, Frederick, Maryland, United States of America
| | - S. P. Lovett
- Center for Genome Sciences, USAMRIID, Frederick, Maryland, United States of America
| | - G. F. Palacios
- Center for Genome Sciences, USAMRIID, Frederick, Maryland, United States of America
| | - R. G. Toothman
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, Maryland, United States of America
| | - J. A. Bozue
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, Maryland, United States of America
| | - P. L. Worsham
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, Maryland, United States of America
| | - S. L. Welkos
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, Maryland, United States of America
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Bernhards RC, Cote CK, Amemiya K, Waag DM, Klimko CP, Worsham PL, Welkos SL. Characterization of in vitro phenotypes of Burkholderia pseudomallei and Burkholderia mallei strains potentially associated with persistent infection in mice. Arch Microbiol 2016; 199:277-301. [PMID: 27738703 PMCID: PMC5306356 DOI: 10.1007/s00203-016-1303-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 09/18/2016] [Accepted: 09/29/2016] [Indexed: 12/29/2022]
Abstract
Burkholderia pseudomallei (Bp) and Burkholderia mallei (Bm), the agents of melioidosis and glanders, respectively, are Tier 1 biothreats. They infect humans and animals, causing disease ranging from acute and fatal to protracted and chronic. Chronic infections are especially challenging to treat, and the identification of in vitro phenotypic markers which signal progression from acute to persistent infection would be extremely valuable. First, a phenotyping strategy was developed employing colony morphotyping, chemical sensitivity testing, macrophage infection, and lipopolysaccharide fingerprint analyses to distinguish Burkholderia strains. Then mouse spleen isolates collected 3–180 days after infection were characterized phenotypically. Isolates from long-term infections often exhibited increased colony morphology differences and altered patterns of antimicrobial sensitivity and macrophage infection. Some of the Bp and Bm persistent infection isolates clearly displayed enhanced virulence in mice. Future studies will evaluate the potential role and significance of these phenotypic markers in signaling the establishment of a chronic infection.
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Affiliation(s)
- R C Bernhards
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), 1425 Porter Street, Fort Detrick, Frederick, MD, 21702-5011, USA
- Present Address: Edgewood Chemical Biological Centre, Aberdeen Proving Ground, Edgewood, MD, 21010-5424, USA
| | - C K Cote
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), 1425 Porter Street, Fort Detrick, Frederick, MD, 21702-5011, USA
| | - K Amemiya
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), 1425 Porter Street, Fort Detrick, Frederick, MD, 21702-5011, USA
| | - D M Waag
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), 1425 Porter Street, Fort Detrick, Frederick, MD, 21702-5011, USA
| | - C P Klimko
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), 1425 Porter Street, Fort Detrick, Frederick, MD, 21702-5011, USA
| | - P L Worsham
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), 1425 Porter Street, Fort Detrick, Frederick, MD, 21702-5011, USA
| | - S L Welkos
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), 1425 Porter Street, Fort Detrick, Frederick, MD, 21702-5011, USA.
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Mikonranta L, Mappes J, Laakso J, Ketola T. Within-host evolution decreases virulence in an opportunistic bacterial pathogen. BMC Evol Biol 2015; 15:165. [PMID: 26282271 PMCID: PMC4539714 DOI: 10.1186/s12862-015-0447-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 08/06/2015] [Indexed: 12/15/2022] Open
Abstract
Background Pathogens evolve in a close antagonistic relationship with their hosts. The conventional theory proposes that evolution of virulence is highly dependent on the efficiency of direct host-to-host transmission. Many opportunistic pathogens, however, are not strictly dependent on the hosts due to their ability to reproduce in the free-living environment. Therefore it is likely that conflicting selection pressures for growth and survival outside versus within the host, rather than transmission potential, shape the evolution of virulence in opportunists. We tested the role of within-host selection in evolution of virulence by letting a pathogen Serratia marcescens db11 sequentially infect Drosophila melanogaster hosts and then compared the virulence to strains that evolved only in the outside-host environment. Results We found that the pathogen adapted to both Drosophila melanogaster host and novel outside-host environment, leading to rapid evolutionary changes in the bacterial life-history traits including motility, in vitro growth rate, biomass yield, and secretion of extracellular proteases. Most significantly, selection within the host led to decreased virulence without decreased bacterial load while the selection lines in the outside-host environment maintained the same level of virulence with ancestral bacteria. Conclusions This experimental evidence supports the idea that increased virulence is not an inevitable consequence of within-host adaptation even when the epidemiological restrictions are removed. Evolution of attenuated virulence could occur because of immune evasion within the host. Alternatively, rapid fluctuation between outside-host and within-host environments, which is typical for the life cycle of opportunistic bacterial pathogens, could lead to trade-offs that lower pathogen virulence.
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Affiliation(s)
- Lauri Mikonranta
- Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, 40014, Jyväskylä, Finland.
| | - Johanna Mappes
- Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, 40014, Jyväskylä, Finland.
| | - Jouni Laakso
- Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, 40014, Jyväskylä, Finland. .,Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, University of Helsinki, University of Helsinki, P.O. Box 65, 00014, Helsinki, Finland.
| | - Tarmo Ketola
- Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, 40014, Jyväskylä, Finland.
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Assessing Pseudomonas aeruginosa virulence using a nonmammalian host: Dictyostelium discoideum. Methods Mol Biol 2014; 1149:671-80. [PMID: 24818941 DOI: 10.1007/978-1-4939-0473-0_51] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
Abstract
Dictyostelium discoideum, a soil amoeba, can be used as an alternative host to study the virulence of various bacterial species, including Pseudomonas aeruginosa. A simple quantitative test based on the ability of D. discoideum to grow on a bacterial lawn has been developed using this amoeba to assay the virulence of P. aeruginosa strains. The assay needs to be customized for the strains to be tested in order to be able to discriminate between virulent and avirulent P. aeruginosa strains. These steps are described in this protocol.
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Vidal-Quist JC, O'Sullivan LA, Desert A, Fivian-Hughes AS, Millet C, Jones TH, Weightman AJ, Rogers HJ, Berry C, Mahenthiralingam E. Arabidopsis thaliana and Pisum sativum models demonstrate that root colonization is an intrinsic trait of Burkholderia cepacia complex bacteria. MICROBIOLOGY (READING, ENGLAND) 2014; 160:373-384. [PMID: 24327425 DOI: 10.1099/mic.0.074351-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
Burkholderia cepacia complex (Bcc) bacteria possess biotechnologically useful properties that contrast with their opportunistic pathogenicity. The rhizosphere fitness of Bcc bacteria is central to their biocontrol and bioremediation activities. However, it is not known whether this differs between species or between environmental and clinical strains. We investigated the ability of 26 Bcc strains representing nine different species to colonize the roots of Arabidopsis thaliana and Pisum sativum (pea). Viable counts, scanning electron microscopy and bioluminescence imaging were used to assess root colonization, with Bcc bacteria achieving mean (±sem) levels of 2.49±0.23×10(6) and 5.16±1.87×10(6) c.f.u. per centimetre of root on the A. thaliana and P. sativum models, respectively. The A. thaliana rhizocompetence model was able to reveal loss of colonization phenotypes in Burkholderia vietnamiensis G4 transposon mutants that had only previously been observed in competition experiments on the P. sativum model. Different Bcc species colonized each plant model at different rates, and no statistical difference in root colonization was observed between isolates of clinical or environmental origin. Loss of the virulence-associated third chromosomal replicon (>1 Mb DNA) did not alter Bcc root colonization on A. thaliana. In summary, Bcc bacteria possess intrinsic root colonization abilities irrespective of their species or source. As Bcc rhizocompetence does not require their third chromosomal replicon, the possibility of using synthetic biology approaches to engineer virulence-attenuated biotechnological strains is tractable.
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Affiliation(s)
- J Cristian Vidal-Quist
- Organisms and Environment Division, Cardiff School of Biosciences, Cardiff University, Cardiff, UK
| | - Louise A O'Sullivan
- Organisms and Environment Division, Cardiff School of Biosciences, Cardiff University, Cardiff, UK
| | - Annaëlle Desert
- Organisms and Environment Division, Cardiff School of Biosciences, Cardiff University, Cardiff, UK
| | - Amanda S Fivian-Hughes
- MRC Centre for Molecular Bacteriology and Infection, G20 Flowers Building, Imperial College London, London, UK
| | - Coralie Millet
- Organisms and Environment Division, Cardiff School of Biosciences, Cardiff University, Cardiff, UK
| | - T Hefin Jones
- Organisms and Environment Division, Cardiff School of Biosciences, Cardiff University, Cardiff, UK
| | - Andrew J Weightman
- Organisms and Environment Division, Cardiff School of Biosciences, Cardiff University, Cardiff, UK
| | - Hilary J Rogers
- Organisms and Environment Division, Cardiff School of Biosciences, Cardiff University, Cardiff, UK
| | - Colin Berry
- Organisms and Environment Division, Cardiff School of Biosciences, Cardiff University, Cardiff, UK
| | - Eshwar Mahenthiralingam
- Organisms and Environment Division, Cardiff School of Biosciences, Cardiff University, Cardiff, UK
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Silva IN, Tavares AC, Ferreira AS, Moreira LM. Stress conditions triggering mucoid morphotype variation in Burkholderia species and effect on virulence in Galleria mellonella and biofilm formation in vitro. PLoS One 2013; 8:e82522. [PMID: 24358195 PMCID: PMC3865030 DOI: 10.1371/journal.pone.0082522] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Accepted: 10/24/2013] [Indexed: 11/18/2022] Open
Abstract
Burkholderia cepacia complex (Bcc) bacteria are opportunistic pathogens causing chronic respiratory infections particularly among cystic fibrosis patients. During these chronic infections, mucoid-to-nonmucoid morphotype variation occurs, with the two morphotypes exhibiting different phenotypic properties. Here we show that in vitro, the mucoid clinical isolate Burkholderia multivorans D2095 gives rise to stable nonmucoid variants in response to prolonged stationary phase, presence of antibiotics, and osmotic and oxidative stresses. Furthermore, in vitro colony morphotype variation within other members of the Burkholderia genus occurred in Bcc and non-Bcc strains, irrespectively of their clinical or environmental origin. Survival to starvation and iron limitation was comparable for the mucoid parental isolate and the respective nonmucoid variant, while susceptibility to antibiotics and to oxidative stress was increased in the nonmucoid variants. Acute infection of Galleria mellonella larvae showed that, in general, the nonmucoid variants were less virulent than the respective parental mucoid isolate, suggesting a role for the exopolysaccharide in virulence. In addition, most of the tested nonmucoid variants produced more biofilm biomass than their respective mucoid parental isolate. As biofilms are often associated with increased persistence of pathogens in the CF lungs and are an indicative of different cell-to-cell interactions, it is possible that the nonmucoid variants are better adapted to persist in this host environment.
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Affiliation(s)
- Inês N. Silva
- Institute for Biotechnology and Bioengineering, Centre for Biological and Chemical Engineering, Instituto Superior Técnico, Lisbon, Portugal
| | - Andreia C. Tavares
- Institute for Biotechnology and Bioengineering, Centre for Biological and Chemical Engineering, Instituto Superior Técnico, Lisbon, Portugal
| | - Ana S. Ferreira
- Institute for Biotechnology and Bioengineering, Centre for Biological and Chemical Engineering, Instituto Superior Técnico, Lisbon, Portugal
| | - Leonilde M. Moreira
- Department of Bioengineering, Instituto Superior Técnico, Lisbon University, Lisbon, Portugal
- Institute for Biotechnology and Bioengineering, Centre for Biological and Chemical Engineering, Instituto Superior Técnico, Lisbon, Portugal
- * E-mail:
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18
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Shrestha RK, Rosenberg T, Makarovsky D, Eckshtain-Levi N, Zelinger E, Kopelowitz J, Sikorski J, Burdman S. Phenotypic variation in the plant pathogenic bacterium Acidovorax citrulli. PLoS One 2013; 8:e73189. [PMID: 24023830 PMCID: PMC3759439 DOI: 10.1371/journal.pone.0073189] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Accepted: 07/17/2013] [Indexed: 11/18/2022] Open
Abstract
Acidovorax citrulli causes bacterial fruit blotch (BFB) of cucurbits, a disease that threatens the cucurbit industry worldwide. Despite the economic importance of BFB, little is known about pathogenicity and fitness strategies of the bacterium. We have observed the phenomenon of phenotypic variation in A. citrulli. Here we report the characterization of phenotypic variants (PVs) of two strains, M6 and 7a1, isolated from melon and watermelon, respectively. Phenotypic variation was observed following growth in rich medium, as well as upon isolation of bacteria from inoculated plants or exposure to several stresses, including heat, salt and acidic conditions. When grown on nutrient agar, all PV colonies possessed a translucent appearance, in contrast to parental strain colonies that were opaque. After 72 h, PV colonies were bigger than parental colonies, and had a fuzzy appearance relative to parental strain colonies that are relatively smooth. A. citrulli colonies are generally surrounded by haloes detectable by the naked eye. These haloes are formed by type IV pilus (T4P)-mediated twitching motility that occurs at the edge of the colony. No twitching haloes could be detected around colonies of both M6 and 7a1 PVs, and microscopy observations confirmed that indeed the PVs did not perform twitching motility. In agreement with these results, transmission electron microscopy revealed that M6 and 7a1 PVs do not produce T4P under tested conditions. PVs also differed from their parental strain in swimming motility and biofilm formation, and interestingly, all assessed variants were less virulent than their corresponding parental strains in seed transmission assays. Slight alterations could be detected in some DNA fingerprinting profiles of 7a1 variants relative to the parental strain, while no differences at all could be seen among M6 variants and parental strain, suggesting that, at least in the latter, phenotypic variation is mediated by slight genetic and/or epigenetic alterations.
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Affiliation(s)
- Ram Kumar Shrestha
- The Department of Plant Pathology and Microbiology and the Minerva Otto Warburg Center for Agricultural Biotechnology, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Tally Rosenberg
- The Department of Plant Pathology and Microbiology and the Minerva Otto Warburg Center for Agricultural Biotechnology, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Daria Makarovsky
- The Department of Plant Pathology and Microbiology and the Minerva Otto Warburg Center for Agricultural Biotechnology, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Noam Eckshtain-Levi
- The Department of Plant Pathology and Microbiology and the Minerva Otto Warburg Center for Agricultural Biotechnology, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Einat Zelinger
- The Interdepartmental Equipment Facility, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | | | - Johannes Sikorski
- Leibniz Institut DSMZ-Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH, Braunschweig, Germany
| | - Saul Burdman
- The Department of Plant Pathology and Microbiology and the Minerva Otto Warburg Center for Agricultural Biotechnology, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
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19
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Kim SB, Timmusk S. A Simplified Method for Gene Knockout and Direct Screening of Recombinant Clones for Application in Paenibacillus polymyxa. PLoS One 2013; 8:e68092. [PMID: 23826364 PMCID: PMC3694910 DOI: 10.1371/journal.pone.0068092] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Accepted: 05/24/2013] [Indexed: 11/19/2022] Open
Abstract
Background Paenibacillus polymyxa is a bacterium widely used in agriculture, industry, and environmental remediation because it has multiple functions including nitrogen fixation and produces various biologically active compounds. Among these compounds are the antibiotics polymyxins, and the bacterium is currently being reassessed for medical application. However, a lack of genetic tools for manipulation of P. polymyxa has limited our understanding of the biosynthesis of these compounds. Methods and Principal Findings To facilitate an understanding of the genetic determinants of the bacterium, we have developed a system for marker exchange mutagenesis directly on competent cells of P. polymyxa under conditions where homologous recombination is enhanced by denaturation of the suicide plasmid DNA. To test this system, we targeted P. polymyxa α-and β-amylase genes for disruption. Chloramphenicol or erythromycin resistance genes were inserted into the suicide plasmid pGEM7Z-f+ (Promega). To mediate homologous recombination and replacement of the targeted genes with the antibiotic resistance genes nucleotide sequences of the α-and β-amylase genes were cloned into the plasmid flanking the antibiotic resistance genes. Conclusions We have created a simple system for targeted gene deletion in P. polymyxa E681. We propose that P. polymyxa isogenic mutants could be developed using this system of marker exchange mutagenesis. α-and β-amylase genes provide a useful tool for direct recombinant screening in P. polymyxa.
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Affiliation(s)
- Seong-Bin Kim
- Department of Forest Mycology and Plant Pathology, Uppsala BioCenter, SLU, Uppsala, Sweden
| | - Salme Timmusk
- Department of Forest Mycology and Plant Pathology, Uppsala BioCenter, SLU, Uppsala, Sweden
- * E-mail:
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Chapalain A, Vial L, Laprade N, Dekimpe V, Perreault J, Déziel E. Identification of quorum sensing-controlled genes in Burkholderia ambifaria. Microbiologyopen 2013; 2:226-42. [PMID: 23382083 PMCID: PMC3633348 DOI: 10.1002/mbo3.67] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Revised: 12/18/2012] [Accepted: 12/26/2012] [Indexed: 01/23/2023] Open
Abstract
The Burkholderia cepacia complex (Bcc) comprises strains with a virulence potential toward immunocompromised patients as well as plant growth-promoting rhizobacteria (PGPR). Owing to the link between quorum sensing (QS) and virulence, most studies among Bcc species have been directed toward QS of pathogenic bacteria. We have investigated the QS of B. ambifaria, a PGPR only infrequently recovered from patients. The cepI gene, responsible for the synthesis of the main signaling molecule N-octanoylhomoserine lactone (C8 -HSL), was inactivated. Phenotypes of the B. ambifaria cepI mutant we observed, such as increased production of siderophores and decreased proteolytic and antifungal activities, are in agreement with those of other Bcc cepI mutants. The cepI mutant was then used as background strain for a whole-genome transposon-insertion mutagenesis strategy, allowing the identification of 20 QS-controlled genes, corresponding to 17 loci. The main functions identified are linked to antifungal and antimicrobial properties, as we have identified QS-controlled genes implicated in the production of pyrrolnitrin, burkholdines (occidiofungin-like molecules), and enacyloxins. This study provides insights in the QS-regulated functions of a PGPR, which could lead to beneficial potential biotechnological applications.
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Affiliation(s)
- Annelise Chapalain
- INRS-Institut Armand-Frappier, 531 bd des Prairies, Laval, Quebec H7V 1B7, Canada
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Utility of insects for studying human pathogens and evaluating new antimicrobial agents. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2013; 135:1-25. [PMID: 23604210 DOI: 10.1007/10_2013_194] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/06/2022]
Abstract
Insect models, such as Galleria mellonella and Drosophila melanogaster have significant ethical, logistical, and economic advantages over mammalian models for the studies of infectious diseases. Using these models, various pathogenic microbes have been studied and many novel virulence genes have been identified. Notably, because insects are susceptible to a wide variety of human pathogens and have immune responses similar to those of mammals, they offer the opportunity to understand innate immune responses against human pathogens better. It is important to note that insect pathosystems have also offered a simple strategy to evaluate the efficacy and toxicity of many antimicrobial agents. Overall, insect models provide a rapid, inexpensive, and reliable way as complementary hosts to conventional vertebrate animal models to study pathogenesis and antimicrobial agents.
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22
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Mikonranta L, Friman VP, Laakso J. Life history trade-offs and relaxed selection can decrease bacterial virulence in environmental reservoirs. PLoS One 2012; 7:e43801. [PMID: 22937098 PMCID: PMC3427151 DOI: 10.1371/journal.pone.0043801] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Accepted: 07/26/2012] [Indexed: 12/13/2022] Open
Abstract
Pathogen virulence is usually thought to evolve in reciprocal selection with the host. While this might be true for obligate pathogens, the life histories of opportunistic pathogens typically alternate between within-host and outside-host environments during the infection-transmission cycle. As a result, opportunistic pathogens are likely to experience conflicting selection pressures across different environments, and this could affect their virulence through life-history trait correlations. We studied these correlations experimentally by exposing an opportunistic bacterial pathogen Serratia marcescens to its natural protist predator Tetrahymena thermophila for 13 weeks, after which we measured changes in bacterial traits related to both anti-predator defence and virulence. We found that anti-predator adaptation (producing predator-resistant biofilm) caused a correlative attenuation in virulence. Even though the direct mechanism was not found, reduction in virulence was most clearly connected to a predator-driven loss of a red bacterial pigment, prodigiosin. Moreover, life-history trait evolution was more divergent among replicate populations in the absence of predation, leading also to lowered virulence in some of the 'predator absent' selection lines. Together these findings suggest that the virulence of non-obligatory, opportunistic bacterial pathogens can decrease in environmental reservoirs through life history trade-offs, or random accumulation of mutations that impair virulence traits under relaxed selection.
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Affiliation(s)
- Lauri Mikonranta
- Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland.
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Dallaire-Dufresne S, Paquet VE, Charette SJ. [Dictyostelium discoideum: a model for the study of bacterial virulence]. Can J Microbiol 2012; 57:699-707. [PMID: 21877947 DOI: 10.1139/w11-072] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The amoeba Dictyostelium discoideum, a bacterial predator, has emerged as a valuable tool for studying bacterial virulence. All its features make this unicellular eukaryote a versatile model organism. It can be used to study virulence factors of pathogenic bacteria as well as host elements involved in resistance to pathogens. The virulence of more than 20 bacterial species pathogenic for humans or animals has been studied using D. discoideum so far. These bacteria are either extracellular or intracellular pathogens. This review presents an overview of the question, with special emphasis on the reasons why D. discoideum is a suitable host model to study bacterial virulence, as well as on the type of information on host–pathogen relationship this amoeba can provide.
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Affiliation(s)
- Stéphanie Dallaire-Dufresne
- Institut de biologie intégrative et des systèmes, Pavillon Charles-Eugène-Marchand, Université Laval, 1030 avenue de la Médecine, Québec, QC G1V 0A6, Canada
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Diversity of potential pathogenicity and biofilm formation among Burkholderia cepacia complex water, clinical, and agricultural isolates in China. World J Microbiol Biotechnol 2012; 28:2113-23. [PMID: 22806034 DOI: 10.1007/s11274-012-1016-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Accepted: 01/30/2012] [Indexed: 01/31/2023]
Abstract
A collection of 70 Burkholderia cepacia complex isolates, recovered from clinical, water, and agricultural resources in China in our previous studies, were tested to assess their potential pathogenicity and association of biofilm formation with pathogenicity. The pathogenicity was tested in the alternative infection models alfalfa, detached lettuce midrib, Galleria mellonella (wax moth), rat agar bead, and lettuce intact leaves. Severe to moderate pathogenicity were observed for isolates of clinical and water origin compared to agricultural isolates, with the exception of a few clinical isolates exhibiting reduced pathogenicity. Virulent isolates persisted in rat lungs until 21 days post infection causing histopathological changes like inflammation, while in lettuce midrib tissues invasion, localization, and replication of bacteria were observed. Biofilm formation ability was also documented in high frequency among water and clinical virulent isolates compared to agricultural isolates. Although variations in pathogenicity were observed for a few isolates, results obtained from different model systems including lettuce were consistent. Our studies indicate that water and clinical isolates showed severe virulence and strong biofilm formation ability compared to agricultural isolates. The results also show lettuce as a promising infection model not only to study the pathogenicity factors used by Bcc bacteria but also for characterization the in vivo transcriptional profile for different niches adaptation of this opportunistic pathogen.
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Bevivino A, Pirone L, Pilkington R, Cifani N, Dalmastri C, Callaghan M, Ascenzioni F, McClean S. Interaction of environmental Burkholderia cenocepacia strains with cystic fibrosis and non-cystic fibrosis bronchial epithelial cells in vitro. MICROBIOLOGY-SGM 2012; 158:1325-1333. [PMID: 22322958 DOI: 10.1099/mic.0.056986-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Burkholderia cenocepacia is an important human pathogen in patients with cystic fibrosis (CF). Non-clinical reservoirs may play a role in the acquisition of infection, so it is important to evaluate the pathogenic potential of environmental B. cenocepacia isolates. In this study, we investigated the interactions of two environmental B. cenocepacia strains (Mex1 and MCII-168) with two bronchial epithelial cell lines, 16HBE14o(-) and CFBE41o(-), which have a non-CF and a CF phenotype, respectively. The environmental strains showed a significantly lower level of invasion into both CF and non-CF cells in comparison with the clinical B. cenocepacia LMG16656(T) strain. Exposure of polarized CFBE41o(-) or 16HBE14o(-) cells to the environmental strains resulted in a significant reduction in transepithelial resistance (TER), comparable with that observed following exposure to the clinical strain. A different mechanism of tight junction disruption in CF versus non-CF epithelia was found. In the 16HBE41o(-) cells, the environmental strains resulted in a drop in TER without any apparent effect on tight junction proteins such as zonula occludens-1 (ZO-1). In contrast, in CF cells, the amount of ZO-1 and its localization were clearly altered by the presence of both the environmental strains, comparable with the effect of LMG16656. This study demonstrates that even if the environmental strains are significantly less invasive than the clinical strain, they have an effect on epithelial integrity comparable with that of the clinical strain. Finally, the tight junction regulatory protein ZO-1 appears to be more susceptible to the presence of environmental strains in CF cells than in cells which express a functional cystic fibrosis transmembrane regulator (CFTR).
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Affiliation(s)
- Annamaria Bevivino
- ENEA C.R. Casaccia - Technical Unit for Sustainable Development and Innovation of Agro-Industrial System, Via Anguillarese 301, 00123 Rome, Italy
| | - Luisa Pirone
- Department of Biology and Biotechnology 'C. Darwin', Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy.,ENEA C.R. Casaccia - Technical Unit for Sustainable Development and Innovation of Agro-Industrial System, Via Anguillarese 301, 00123 Rome, Italy
| | - Ruth Pilkington
- Centre of Microbial Host Interactions, Institute of Technology Tallaght, Old Blessington Road, Dublin 2, Ireland
| | - Noemi Cifani
- Department of Biology and Biotechnology 'C. Darwin', Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy
| | - Claudia Dalmastri
- ENEA C.R. Casaccia - Technical Unit for Sustainable Development and Innovation of Agro-Industrial System, Via Anguillarese 301, 00123 Rome, Italy
| | - Máire Callaghan
- Centre of Applied Science for Health, Institute of Technology Tallaght, Old Blessington Road, Dublin 2, Ireland.,Centre of Microbial Host Interactions, Institute of Technology Tallaght, Old Blessington Road, Dublin 2, Ireland
| | - Fiorentina Ascenzioni
- Department of Biology and Biotechnology 'C. Darwin', Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy
| | - Siobhán McClean
- Centre of Applied Science for Health, Institute of Technology Tallaght, Old Blessington Road, Dublin 2, Ireland.,Centre of Microbial Host Interactions, Institute of Technology Tallaght, Old Blessington Road, Dublin 2, Ireland
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Li D, Rothballer M, Engel M, Hoser J, Schmidt T, Kuttler C, Schmid M, Schloter M, Hartmann A. Phenotypic variation in Acidovorax radicisN35 influences plant growth promotion. FEMS Microbiol Ecol 2011; 79:751-62. [PMID: 22107346 DOI: 10.1111/j.1574-6941.2011.01259.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Revised: 11/08/2011] [Accepted: 11/09/2011] [Indexed: 11/27/2022] Open
Abstract
Acidovorax radicis N35, isolated from surface-sterilized wheat roots (Triticum aestivum), showed irreversible phenotypic variation in nutrient broth, resulting in a differing colony morphology. In addition to the wild-type form (rough colony type), a phenotypic variant form (smooth colony type) appeared at a frequency of 3.2 × 10(-3) per cell per generation on NB agar plates. In contrast to the N35 wild type, the variant N35v showed almost no cell aggregation and had lost its flagella and swarming ability. After inoculation, only the wild-type N35 significantly promoted the growth of soil-grown barley plants. After co-inoculation of axenically grown barley seedlings with differentially fluorescently labeled N35 and N35v cells, decreased competitive endophytic root colonization in the phenotypic variant N35v was observed using confocal laser scanning microscopy. In addition, 454 pyrosequencing of both phenotypes revealed almost identical genomic sequences. The only stable difference noted in the sequence of the phenotype variant N35v was a 16-nucleotide deletion identified in a gene encoding the mismatch repair protein MutL. The deletion resulted in a frameshift that revealed a new stop codon resulting in a truncated MutL protein missing a functional MutL C-terminal domain. The mutation was consistent in all investigated phenotype variant cultures and might be responsible for the observed phenotypic variation in A. radicis N35.
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Affiliation(s)
- Dan Li
- Research Unit Microbe-Plant Interactions, Helmholtz Zentrum Muenchen, German Research Center for Environmental Health (GmbH), Neuherberg, Germany
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Abstract
AbstractBacteria belonging to the genus Burkholderia are well known for their adaptability to habitats as diverse as freshwater sediments, lungs of cystic fibrosis patients and plant tissues. This genus includes also plant, animal and human pathogenic species, such as Burkholderia glumae, Burkholderia pseudomallei and the Burkholderia cepacia complex. Over the past few years, several newly discovered non-pathogenic plant associated Burkholderia species have raised particular interest for their potential use in plant growth promotion, biocontrol of plant pathogens, phytoremediation and xenobiotics degradation. Highlights from recent studies on the taxonomy, ecology and pathogenicity of different species of the Burkholderia genus are presented with the aim to evaluate their potential use in biotechnology.
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Burkholderia cenocepacia ShvR-regulated genes that influence colony morphology, biofilm formation, and virulence. Infect Immun 2011; 79:2984-97. [PMID: 21690240 DOI: 10.1128/iai.00170-11] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Burkholderia cenocepacia is an opportunistic pathogen that primarily infects cystic fibrosis (CF) patients. Previously, we reported that ShvR, a LysR regulator, influences colony morphology, virulence, and biofilm formation and regulates the expression of an adjacent 24-kb genomic region encoding 24 genes. In this study, we report the functional characterization of selected genes in this region. A Tn5 mutant with shiny colony morphology was identified with a polar mutation in BCAS0208, predicted to encode an acyl-coenzyme A dehydrogenase. Mutagenesis of BCAS0208 and complementation analyses revealed that BCAS0208 is required for rough colony morphology, biofilm formation, and virulence on alfalfa seedlings. It was not possible to complement with BCAS0208 containing a mutation in the catalytic site. BCAS0201, encoding a putative flavin adenine dinucleotide (FAD)-dependent oxidoreductase, and BCAS0207, encoding a putative citrate synthase, do not influence colony morphology but are required for optimum levels of biofilm formation and virulence. Both BCAS0208 and BCAS0201 contribute to pellicle formation, although individual mutations in each of these genes had no appreciable effect on pellicle formation. A mutant with a polar insertion in BCAS0208 was significantly less virulent in a rat model of chronic lung infection as well as in the alfalfa model. Genes in this region were shown to influence utilization of branched-chain fatty acids, tricarboxylic acid cycle substrates, l-arabinose, and branched-chain amino acids. Together, our data show that the ShvR-regulated genes BCAS0208 to BCAS0201 are required for the rough colony morphotype, biofilm and pellicle formation, and virulence in B. cenocepacia.
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Phase variation: how to create and coordinate population diversity. Curr Opin Microbiol 2011; 14:205-11. [DOI: 10.1016/j.mib.2011.01.002] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Revised: 01/06/2011] [Accepted: 01/07/2011] [Indexed: 12/26/2022]
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Vial L, Chapalain A, Groleau MC, Déziel E. The various lifestyles of theBurkholderia cepaciacomplex species: a tribute to adaptation. Environ Microbiol 2010; 13:1-12. [DOI: 10.1111/j.1462-2920.2010.02343.x] [Citation(s) in RCA: 118] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Construction of aminoglycoside-sensitive Burkholderia cenocepacia strains for use in studies of intracellular bacteria with the gentamicin protection assay. Appl Environ Microbiol 2010; 76:3170-6. [PMID: 20348312 DOI: 10.1128/aem.03024-09] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Burkholderia cenocepacia is a multidrug-resistant opportunistic pathogen that infects the airways of patients with cystic fibrosis (CF) and can survive intracellularly in macrophages and epithelial cells. The gentamicin protection assay, which relies on the poor ability of gentamicin or other aminoglycosides to permeate eukaryotic cell membranes, is traditionally employed to quantify intracellular bacteria. However, the high resistance of these bacteria to aminoglycosides hampers the use of the gentamicin protection assay to investigate intracellular infection by B. cenocepacia. Here, we report the construction of gentamicin-sensitive strains of B. cenocepacia carrying a deletion of the BCAL1674, BCAL1675, and BCAL1676 genes that form an operon encoding an AmrAB-OprA-like efflux pump. We show that bacteria carrying this deletion are hypersensitive to gentamicin and also delay phagolysosomal fusion upon infection of RAW 264.7 murine macrophages, as previously demonstrated for the parental strain. We also demonstrate for the first time that low concentrations of gentamicin can be used to effectively kill extracellular bacteria and reliably quantify the intracellular infection by B. cenocepacia, which can replicate in RAW 264.7 macrophages.
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