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Butt AT, Banyard CD, Haldipurkar SS, Agnoli K, Mohsin M, Vitovski S, Paleja A, Tang Y, Lomax R, Ye F, Green J, Thomas M. OUP accepted manuscript. Nucleic Acids Res 2022; 50:3709-3726. [PMID: 35234897 PMCID: PMC9023288 DOI: 10.1093/nar/gkac137] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 01/28/2022] [Accepted: 02/14/2022] [Indexed: 11/14/2022] Open
Abstract
Burkholderia cenocepacia is an opportunistic pathogen that causes severe infections of the cystic fibrosis (CF) lung. To acquire iron, B. cenocepacia secretes the Fe(III)-binding compound, ornibactin. Genes for synthesis and utilisation of ornibactin are served by the iron starvation (IS) extracytoplasmic function (ECF) σ factor, OrbS. Transcription of orbS is regulated in response to the prevailing iron concentration by the ferric uptake regulator (Fur), such that orbS expression is repressed under iron-sufficient conditions. Here we show that, in addition to Fur-mediated regulation of orbS, the OrbS protein itself responds to intracellular iron availability. Substitution of cysteine residues in the C-terminal region of OrbS diminished the ability to respond to Fe(II) in vivo. Accordingly, whilst Fe(II) impaired transcription from and recognition of OrbS-dependent promoters in vitro by inhibiting the binding of OrbS to core RNA polymerase (RNAP), the cysteine-substituted OrbS variant was less responsive to Fe(II). Thus, the cysteine residues within the C-terminal region of OrbS contribute to an iron-sensing motif that serves as an on-board ‘anti-σ factor’ in the presence of Fe(II). A model to account for the presence two regulators (Fur and OrbS) that respond to the same intracellular Fe(II) signal to control ornibactin synthesis and utilisation is discussed.
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Affiliation(s)
- Aaron T Butt
- Department of Infection, Immunity and Cardiovascular Disease, Faculty of Medicine, Dentistry and Health, University of Sheffield, Sheffield S10 2RX, UK
| | - Christopher D Banyard
- Department of Infection, Immunity and Cardiovascular Disease, Faculty of Medicine, Dentistry and Health, University of Sheffield, Sheffield S10 2RX, UK
| | - Sayali S Haldipurkar
- Department of Infection, Immunity and Cardiovascular Disease, Faculty of Medicine, Dentistry and Health, University of Sheffield, Sheffield S10 2RX, UK
| | - Kirsty Agnoli
- Department of Infection, Immunity and Cardiovascular Disease, Faculty of Medicine, Dentistry and Health, University of Sheffield, Sheffield S10 2RX, UK
| | - Muslim I Mohsin
- Department of Infection, Immunity and Cardiovascular Disease, Faculty of Medicine, Dentistry and Health, University of Sheffield, Sheffield S10 2RX, UK
| | - Srdjan Vitovski
- Department of Infection, Immunity and Cardiovascular Disease, Faculty of Medicine, Dentistry and Health, University of Sheffield, Sheffield S10 2RX, UK
| | - Ameya Paleja
- Department of Infection, Immunity and Cardiovascular Disease, Faculty of Medicine, Dentistry and Health, University of Sheffield, Sheffield S10 2RX, UK
| | - Yingzhi Tang
- Department of Infection, Immunity and Cardiovascular Disease, Faculty of Medicine, Dentistry and Health, University of Sheffield, Sheffield S10 2RX, UK
| | - Rebecca Lomax
- Department of Infection, Immunity and Cardiovascular Disease, Faculty of Medicine, Dentistry and Health, University of Sheffield, Sheffield S10 2RX, UK
| | - Fuzhou Ye
- Section of Structural Biology, Department of Infectious Disease, Imperial College London, Sir Alexander Fleming Building, South Kensington, London SW7 2AZ, UK
| | - Jeffrey Green
- Correspondence may also be addressed to Jeffrey Green. Tel: +44 114 222 4403; Fax: +44 114 222 2800;
| | - Mark S Thomas
- To whom correspondence should be addressed. Tel: +44 114 215 9557; Fax: +44 114 271 1863;
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Foxfire A, Buhrow AR, Orugunty RS, Smith L. Drug discovery through the isolation of natural products from Burkholderia. Expert Opin Drug Discov 2021; 16:807-822. [PMID: 33467922 PMCID: PMC9844120 DOI: 10.1080/17460441.2021.1877655] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Introduction: The increasing threat of antibiotic-resistant pathogens makes it imperative that new antibiotics to combat them are discovered. Burkholderia is a genus of Gram-negative, non-sporulating bacteria. While ubiquitous and capable of growing within plants and groundwater, they are primarily soil-dwelling organisms. These include the more virulent forms of Burkholderia such as Burkholderia mallei, Burkholderia pseudomallei, and the Burkholderia cepacia complex (Bcc).Areas covered: This review provides a synopsis of current research on the natural products isolated from the genus Burkholderia. The authors also cover the research on the drug discovery efforts that have been performed on the natural products derived from Burkholderia.Expert opinion: Though Burkholderia has a small number of pathogenic species, the majority of the genus is avirulent and almost all members of the genus are capable of producing useful antimicrobial products that could potentially lead to the development of novel therapeutics against infectious diseases. The need for discovery of new antibiotics is urgent due to the ever-increasing prevalence of antibiotic-resistant pathogens, coupled with the decline in the discovery of new antibiotics.
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Affiliation(s)
- Adam Foxfire
- Department of Biology, Texas A&M University, College Station, TX 77843
| | - Andrew Riley Buhrow
- Department of Biology, Texas A&M University, College Station, TX 77843,Antimicrobial Division, Sano Chemicals Inc., Bryan, TX 77803
| | | | - Leif Smith
- Department of Biology, Texas A&M University, College Station, TX 77843,Antimicrobial Division, Sano Chemicals Inc., Bryan, TX 77803,Address correspondence to Leif Smith,
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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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Butt AT, Thomas MS. Iron Acquisition Mechanisms and Their Role in the Virulence of Burkholderia Species. Front Cell Infect Microbiol 2017; 7:460. [PMID: 29164069 PMCID: PMC5681537 DOI: 10.3389/fcimb.2017.00460] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 10/18/2017] [Indexed: 11/19/2022] Open
Abstract
Burkholderia is a genus within the β-Proteobacteriaceae that contains at least 90 validly named species which can be found in a diverse range of environments. A number of pathogenic species occur within the genus. These include Burkholderia cenocepacia and Burkholderia multivorans, opportunistic pathogens that can infect the lungs of patients with cystic fibrosis, and are members of the Burkholderia cepacia complex (Bcc). Burkholderia pseudomallei is also an opportunistic pathogen, but in contrast to Bcc species it causes the tropical human disease melioidosis, while its close relative Burkholderia mallei is the causative agent of glanders in horses. For these pathogens to survive within a host and cause disease they must be able to acquire iron. This chemical element is essential for nearly all living organisms due to its important role in many enzymes and metabolic processes. In the mammalian host, the amount of accessible free iron is negligible due to the low solubility of the metal ion in its higher oxidation state and the tight binding of this element by host proteins such as ferritin and lactoferrin. As with other pathogenic bacteria, Burkholderia species have evolved an array of iron acquisition mechanisms with which to capture iron from the host environment. These mechanisms include the production and utilization of siderophores and the possession of a haem uptake system. Here, we summarize the known mechanisms of iron acquisition in pathogenic Burkholderia species and discuss the evidence for their importance in the context of virulence and the establishment of infection in the host. We have also carried out an extensive bioinformatic analysis to identify which siderophores are produced by each Burkholderia species that is pathogenic to humans.
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Affiliation(s)
- Aaron T Butt
- Department of Infection, Immunity and Cardiovascular Disease, Faculty of Medicine, Dentistry and Health, University of Sheffield, Sheffield, United Kingdom
| | - Mark S Thomas
- Department of Infection, Immunity and Cardiovascular Disease, Faculty of Medicine, Dentistry and Health, University of Sheffield, Sheffield, United Kingdom
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Esmaeel Q, Pupin M, Kieu NP, Chataigné G, Béchet M, Deravel J, Krier F, Höfte M, Jacques P, Leclère V. Burkholderia genome mining for nonribosomal peptide synthetases reveals a great potential for novel siderophores and lipopeptides synthesis. Microbiologyopen 2016; 5:512-26. [PMID: 27060604 PMCID: PMC4906002 DOI: 10.1002/mbo3.347] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 01/26/2016] [Accepted: 02/03/2016] [Indexed: 12/20/2022] Open
Abstract
Burkholderia is an important genus encompassing a variety of species, including pathogenic strains as well as strains that promote plant growth. We have carried out a global strategy, which combined two complementary approaches. The first one is genome guided with deep analysis of genome sequences and the second one is assay guided with experiments to support the predictions obtained in silico. This efficient screening for new secondary metabolites, performed on 48 gapless genomes of Burkholderia species, revealed a total of 161 clusters containing nonribosomal peptide synthetases (NRPSs), with the potential to synthesize at least 11 novel products. Most of them are siderophores or lipopeptides, two classes of products with potential application in biocontrol. The strategy led to the identification, for the first time, of the cluster for cepaciachelin biosynthesis in the genome of Burkholderia ambifaria AMMD and a cluster corresponding to a new malleobactin‐like siderophore, called phymabactin, was identified in Burkholderia phymatum STM815 genome. In both cases, the siderophore was produced when the strain was grown in iron‐limited conditions. Elsewhere, the cluster for the antifungal burkholdin was detected in the genome of B. ambifaria AMMD and also Burkholderia sp. KJ006. Burkholderia pseudomallei strains harbor the genetic potential to produce a novel lipopeptide called burkhomycin, containing a peptidyl moiety of 12 monomers. A mixture of lipopeptides produced by Burkholderia rhizoxinica lowered the surface tension of the supernatant from 70 to 27 mN·m−1. The production of nonribosomal secondary metabolites seems related to the three phylogenetic groups obtained from 16S rRNA sequences. Moreover, the genome‐mining approach gave new insights into the nonribosomal synthesis exemplified by the identification of dual C/E domains in lipopeptide NRPSs, up to now essentially found in Pseudomonas strains.
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Affiliation(s)
- Qassim Esmaeel
- University Lille, INRA, ISA, University Artois, University Littoral Côte d'Opale, EA 7394-ICV - Institut Charles Viollette, F-59000, Lille, France
| | - Maude Pupin
- University Lille, CNRS, Centrale Lille, UMR 9189-CRIStAL, Centre de Recherche en Informatique Signal et Automatique de Lille, F-59000, Lille, France.,Bonsai Team, Inria-Lille Nord Europe, F-59655, Villeneuve d'Ascq Cedex, France
| | - Nam Phuong Kieu
- Laboratory of Phytopathology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Gabrielle Chataigné
- University Lille, INRA, ISA, University Artois, University Littoral Côte d'Opale, EA 7394-ICV - Institut Charles Viollette, F-59000, Lille, France
| | - Max Béchet
- University Lille, INRA, ISA, University Artois, University Littoral Côte d'Opale, EA 7394-ICV - Institut Charles Viollette, F-59000, Lille, France
| | - Jovana Deravel
- University Lille, INRA, ISA, University Artois, University Littoral Côte d'Opale, EA 7394-ICV - Institut Charles Viollette, F-59000, Lille, France
| | - François Krier
- University Lille, INRA, ISA, University Artois, University Littoral Côte d'Opale, EA 7394-ICV - Institut Charles Viollette, F-59000, Lille, France
| | - Monica Höfte
- Laboratory of Phytopathology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Philippe Jacques
- University Lille, INRA, ISA, University Artois, University Littoral Côte d'Opale, EA 7394-ICV - Institut Charles Viollette, F-59000, Lille, France
| | - Valérie Leclère
- University Lille, INRA, ISA, University Artois, University Littoral Côte d'Opale, EA 7394-ICV - Institut Charles Viollette, F-59000, Lille, France.,University Lille, CNRS, Centrale Lille, UMR 9189-CRIStAL, Centre de Recherche en Informatique Signal et Automatique de Lille, F-59000, Lille, France.,Bonsai Team, Inria-Lille Nord Europe, F-59655, Villeneuve d'Ascq Cedex, France
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6
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Ooi WF, Ong C, Nandi T, Kreisberg JF, Chua HH, Sun G, Chen Y, Mueller C, Conejero L, Eshaghi M, Ang RML, Liu J, Sobral BW, Korbsrisate S, Gan YH, Titball RW, Bancroft GJ, Valade E, Tan P. The condition-dependent transcriptional landscape of Burkholderia pseudomallei. PLoS Genet 2013; 9:e1003795. [PMID: 24068961 PMCID: PMC3772027 DOI: 10.1371/journal.pgen.1003795] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Accepted: 07/29/2013] [Indexed: 12/25/2022] Open
Abstract
Burkholderia pseudomallei (Bp), the causative agent of the often-deadly infectious disease melioidosis, contains one of the largest prokaryotic genomes sequenced to date, at 7.2 Mb with two large circular chromosomes (1 and 2). To comprehensively delineate the Bp transcriptome, we integrated whole-genome tiling array expression data of Bp exposed to >80 diverse physical, chemical, and biological conditions. Our results provide direct experimental support for the strand-specific expression of 5,467 Sanger protein-coding genes, 1,041 operons, and 766 non-coding RNAs. A large proportion of these transcripts displayed condition-dependent expression, consistent with them playing functional roles. The two Bp chromosomes exhibited dramatically different transcriptional landscapes — Chr 1 genes were highly and constitutively expressed, while Chr 2 genes exhibited mosaic expression where distinct subsets were expressed in a strongly condition-dependent manner. We identified dozens of cis-regulatory motifs associated with specific condition-dependent expression programs, and used the condition compendium to elucidate key biological processes associated with two complex pathogen phenotypes — quorum sensing and in vivo infection. Our results demonstrate the utility of a Bp condition-compendium as a community resource for biological discovery. Moreover, the observation that significant portions of the Bp virulence machinery can be activated by specific in vitro cues provides insights into Bp's capacity as an “accidental pathogen”, where genetic pathways used by the bacterium to survive in environmental niches may have also facilitated its ability to colonize human hosts. Bacterial transcriptomes are dynamic, context-specific and condition-dependent. Infection by the soil bacterium, Burkholderia pseudomallei, causes melioidosis, an often fatal infectious disease of humans and animals. Possessing a large multi-chromosomal genome, B. pseudomallei is able to persist and survive in a multitude of environments. To obtain a comprehensive overview of B. pseudomallei expressed transcripts, we initiated whole-genome transcriptome profiling covering a broad spectrum of conditions and exposures — a so-called “condition compendium”. Using the compendium, we confirmed many previously-annotated genes and operons, and also identified hundreds of novel transcripts including anti-sense transcripts and non-coding RNAs. By systematically examining genes exhibiting highly similar expression patterns, we ascribed putative functions to previously uncharacterized genes, and identified novel regulatory elements controlling these expression patterns. We also used the compendium to elucidate candidate virulence pathways associated with quorum-sensing and infection in mice. Our study showcases the power of a B. pseudomallei condition compendium as a valuable resource for understanding microbial physiology and the pathogenesis of melioidosis.
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Affiliation(s)
- Wen Fong Ooi
- Genome Institute of Singapore, Singapore, Republic of Singapore
| | - Catherine Ong
- 2DMERI@DSO, DSO National Laboratories, Singapore, Republic of Singapore
| | - Tannistha Nandi
- Genome Institute of Singapore, Singapore, Republic of Singapore
| | | | - Hui Hoon Chua
- Genome Institute of Singapore, Singapore, Republic of Singapore
| | - Guangwen Sun
- School of Applied Science, Republic Polytechnic, Singapore, Republic of Singapore
| | - Yahua Chen
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Republic of Singapore
| | - Claudia Mueller
- College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Laura Conejero
- Department of Immunology and Infection, Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Majid Eshaghi
- Genome Institute of Singapore, Singapore, Republic of Singapore
| | - Roy Moh Lik Ang
- Genome Institute of Singapore, Singapore, Republic of Singapore
| | - Jianhua Liu
- Genome Institute of Singapore, Singapore, Republic of Singapore
| | - Bruno W. Sobral
- Virginia Bioinformatics Institute at Virginia Tech, Blacksburg, Virginia, United States of America
| | - Sunee Korbsrisate
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Yunn Hwen Gan
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Republic of Singapore
| | - Richard W. Titball
- College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Gregory J. Bancroft
- Department of Immunology and Infection, Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Eric Valade
- Institut de Recherche Biomédicale des Armées/CRSSA, La Tronche, France
- Ecole du Val-de-Grâce, Paris, France
| | - Patrick Tan
- Genome Institute of Singapore, Singapore, Republic of Singapore
- Duke-NUS Graduate Medical School, Singapore, Republic of Singapore
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Republic of Singapore
- * E-mail:
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Conclusion on the peer review of the pesticide risk assessment of the active substance Pseudomonas sp. strain DSMZ 13134. EFSA J 2012. [DOI: 10.2903/j.efsa.2012.2954] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Regulation of sulfur assimilation pathways in Burkholderia cenocepacia through control of genes by the SsuR transcription factor. J Bacteriol 2011; 193:1843-53. [PMID: 21317335 DOI: 10.1128/jb.00483-10] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The genome of Burkholderia cenocepacia contains two genes encoding closely related LysR-type transcriptional regulators, CysB and SsuR, involved in control of sulfur assimilation processes. In this study we show that the function of SsuR is essential for the utilization of a number of organic sulfur sources of either environmental or human origin. Among the genes upregulated by SsuR identified here are the tauABC operon encoding a predicted taurine transporter, three tauD-type genes encoding putative taurine dioxygenases, and atsA encoding a putative arylsulfatase. The role of SsuR in expression of these genes/operons was characterized through (i) construction of transcriptional reporter fusions to candidate promoter regions and analysis of their expression in the presence/absence of SsuR and (ii) testing the ability of SsuR to bind SsuR-responsive promoter regions. We also demonstrate that expression of SsuR-activated genes is not repressed in the presence of inorganic sulfate. A more detailed analysis of four SsuR-responsive promoter regions indicated that ~44 bp of the DNA sequence preceding and/or overlapping the predicted -35 element of such promoters is sufficient for SsuR binding. The DNA sequence homology among SsuR "recognition motifs" at different responsive promoters appears to be limited.
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Asghar AH, Shastri S, Dave E, Wowk I, Agnoli K, Cook AM, Thomas MS. The pobA gene of Burkholderia cenocepacia encodes a Group I Sfp-type phosphopantetheinyltransferase required for biosynthesis of the siderophores ornibactin and pyochelin. Microbiology (Reading) 2011; 157:349-361. [DOI: 10.1099/mic.0.045559-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The opportunistic pathogen Burkholderia cenocepacia produces the siderophores ornibactin and pyochelin under iron-restricted conditions. Biosynthesis of both siderophores requires the involvement of non-ribosomal peptide synthetases (NRPSs). Using a transposon containing the lacZ reporter gene, two B. cenocepacia mutants were isolated which were deficient in siderophore production. Mutant IW10 was shown to produce normal amounts of ornibactin but only trace amounts of pyochelin, whereas synthesis of both siderophores was abolished in AHA27. Growth of AHA27, but not IW10, was inhibited under iron-restricted conditions. In both mutants, the transposon had integrated into the pobA gene, which encodes a polypeptide exhibiting similarity to the Sfp-type phosphopantetheinyltransferases (PPTases). These enzymes are responsible for activation of NRPSs by the covalent attachment of the 4′-phosphopantetheine (P-pant) moiety of coenzyme A. Previously characterized PPTase genes from other bacteria were shown to efficiently complement both mutants for siderophore production when provided in trans. The B. cenocepacia pobA gene was also able to efficiently complement an Escherichia coli entD mutant for production of the siderophore enterobactin. Using mutant IW10, in which the lacZ gene carried by the transposon is inserted in the same orientation as pobA, it was shown that pobA is not appreciably iron-regulated. Finally, we confirmed that Sfp-type bacterial PPTases can be subdivided into two distinct groups, and we present the amino acid signature sequences which characterize each of these groups.
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Affiliation(s)
- Atif H. Asghar
- Department of Infection and Immunity, The Medical School, University of Sheffield, Beech Hill Road, Sheffield S10 2RX, UK
| | - Sravanthi Shastri
- Department of Infection and Immunity, The Medical School, University of Sheffield, Beech Hill Road, Sheffield S10 2RX, UK
| | - Emma Dave
- Department of Infection and Immunity, The Medical School, University of Sheffield, Beech Hill Road, Sheffield S10 2RX, UK
| | - Irena Wowk
- Department of Infection and Immunity, The Medical School, University of Sheffield, Beech Hill Road, Sheffield S10 2RX, UK
| | - Kirsty Agnoli
- Department of Infection and Immunity, The Medical School, University of Sheffield, Beech Hill Road, Sheffield S10 2RX, UK
| | - Anne M. Cook
- Department of Infection and Immunity, The Medical School, University of Sheffield, Beech Hill Road, Sheffield S10 2RX, UK
| | - Mark S. Thomas
- Department of Infection and Immunity, The Medical School, University of Sheffield, Beech Hill Road, Sheffield S10 2RX, UK
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Agnoli K, Lowe CA, Farmer KL, Husnain SI, Thomas MS. The ornibactin biosynthesis and transport genes of Burkholderia cenocepacia are regulated by an extracytoplasmic function sigma factor which is a part of the Fur regulon. J Bacteriol 2006; 188:3631-44. [PMID: 16672617 PMCID: PMC1482860 DOI: 10.1128/jb.188.10.3631-3644.2006] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2005] [Accepted: 02/13/2006] [Indexed: 11/20/2022] Open
Abstract
Burkholderia cenocepacia mutants that fail to produce the siderophore ornibactin were obtained following mutagenesis with mini-Tn5Tp. These mutants were shown to be growth restricted under conditions of iron depletion. In eight of the mutants, the transposon had integrated into one of two genes, orbI and orbJ, encoding nonribosomal peptide synthetases. In the other mutant, the transposon had inserted into an open reading frame, orbS, located upstream from orbI. The polypeptide product of orbS exhibits a high degree of similarity to the Pseudomonas aeruginosa extracytoplasmic function (ECF) sigma factor PvdS but possesses an N-terminal extension of approximately 29 amino acids that is not present in PvdS. Three predicted OrbS-dependent promoters were identified within the ornibactin gene cluster, based on their similarity to PvdS-dependent promoters. The iron-regulated activity of these promoters was shown to require OrbS. Transcription of the orbS gene was found to be under the control of an iron-regulated sigma(70)-dependent promoter. This promoter, but not the OrbS-dependent promoters, was shown to be a target for repression by the global regulator Fur. Our results demonstrate that production of ornibactin by B. cenocepacia in response to iron starvation requires transcription of an operon that is dependent on the Fur-regulated ECF sigma factor gene orbS. A mechanism is also proposed for the biosynthesis of ornibactin.
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Affiliation(s)
- Kirsty Agnoli
- Division of Genomic Medicine, School of Medicine and Biomedical Sciences, University of Sheffield, UK
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Visser MB, Majumdar S, Hani E, Sokol PA. Importance of the ornibactin and pyochelin siderophore transport systems in Burkholderia cenocepacia lung infections. Infect Immun 2004; 72:2850-7. [PMID: 15102796 PMCID: PMC387874 DOI: 10.1128/iai.72.5.2850-2857.2004] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Previously, orbA, the gene encoding the outer membrane receptor for ferric-ornibactin, was identified in Burkholderia cenocepacia K56-2, a strain which produces ornibactin, salicylic acid, and negligible amounts of pyochelin. A K56-2 orbA mutant was less virulent than the parent strain in a rat agar bead infection model. In this study, an orbA mutant of B. cenocepacia Pc715j which produces pyochelin in addition to ornibactin and salicylic acid was constructed. The gene encoding the outer membrane receptor for ferric-pyochelin (fptA) was also identified. An fptA mutant was constructed in Pc715j and shown to be deficient in [(59)Fe]pyochelin uptake. A 75-kDa iron-regulated protein was identified in outer membrane preparations of Pc715j that was absent in outer membrane preparations of Pc715jfptA::tp. Pc715jfptA::tp and Pc715jorbA::tp produced smaller amounts of their corresponding siderophores. Both Pc715jorbA::tp and Pc715jfptA::tp were able to grow in iron starvation conditions in vitro. In the agar bead model, the Pc715jorbA::tp mutant was cleared from the lung, indicating that the pyochelin uptake system does not compensate for the absence of a functional ornibactin system. Pc715jfptA::tp persisted in rat lung infections in numbers similar to those of the parent strain, indicating that the ferric-ornibactin uptake system could compensate for the defect in ferric-pyochelin uptake in vivo. These studies suggest that the ornibactin uptake system is the most important siderophore-mediated iron transport system in B. cenocepacia lung infections.
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Affiliation(s)
- M B Visser
- Department of Microbiology and Infectious Diseases, University of Calgary Health Sciences Center, Calgary, Alberta T2N 4N1, Canada
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12
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Lowe CA, Asghar AH, Shalom G, Shaw JG, Thomas MS. The Burkholderia cepacia fur gene: co-localization with omlA and absence of regulation by iron. MICROBIOLOGY (READING, ENGLAND) 2001; 147:1303-1314. [PMID: 11320133 DOI: 10.1099/00221287-147-5-1303] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The ferric uptake regulator (Fur) functions as a transcription repressor of many genes in bacteria in response to iron, but the presence of a functional equivalent of this protein has not been demonstrated in Burkholderia cepacia. A segment of the Burkholderia pseudomallei fur gene was amplified using degenerate primers and used to identify chromosomal restriction fragments containing the entire fur genes of B. cepacia and B. pseudomallei. These fragments were cloned and sequenced, revealing the Fur protein of both species to be a polypeptide of 142 amino acids possessing a high degree of amino acid sequence identity to Fur of other members of the beta subclass of the Proteobacteria. Primer extension analysis demonstrated that transcription of B. cepacia fur originated from a single promoter located 36 bp upstream from the fur translation initiation codon. The Fur polypeptide of B. cepacia was shown to functionally substitute for Fur in an Escherichia coli fur mutant. Single copy fur-lacZ fusions were constructed and used to examine the regulation of B. cepacia fur. The B. cepacia fur promoter was not responsive to iron availability, the presence of hydrogen peroxide or the superoxide generator methyl viologen. In addition, fur expression was not significantly influenced by carbon source. Interestingly, the presence of the divergently transcribed omlA/smpA gene upstream of fur in some members of the gamma subclass of the Proteobacteria is retained in several genera within the beta taxon, including Burkholderia.
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Affiliation(s)
- Carolyn A Lowe
- Division of Genomic Medicine, F floor, University of Sheffield Medical School, Beech Hill Road, Sheffield S10 2RX, UK1
| | - Atif H Asghar
- Division of Genomic Medicine, F floor, University of Sheffield Medical School, Beech Hill Road, Sheffield S10 2RX, UK1
| | - Gil Shalom
- Division of Genomic Medicine, F floor, University of Sheffield Medical School, Beech Hill Road, Sheffield S10 2RX, UK1
| | - Jonathan G Shaw
- Division of Genomic Medicine, F floor, University of Sheffield Medical School, Beech Hill Road, Sheffield S10 2RX, UK1
| | - Mark S Thomas
- Division of Genomic Medicine, F floor, University of Sheffield Medical School, Beech Hill Road, Sheffield S10 2RX, UK1
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13
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Sokol PA, Darling P, Woods DE, Mahenthiralingam E, Kooi C. Role of ornibactin biosynthesis in the virulence of Burkholderia cepacia: characterization of pvdA, the gene encoding L-ornithine N(5)-oxygenase. Infect Immun 1999; 67:4443-55. [PMID: 10456885 PMCID: PMC96763 DOI: 10.1128/iai.67.9.4443-4455.1999] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Burkholderia cepacia is a frequent cause of respiratory infections in cystic fibrosis patients. B. cepacia has been shown to produce at least four siderophores which may play a role in the virulence of this organism. To characterize genes involved in the synthesis of siderophores, Tn5-OT182 mutants were isolated in strain K56-2, which produces two siderophores, salicylic acid (SA) and ornibactins. Two mutants were characterized that did not produce zones on Chrome Azurol S agar in a commonly used assay to detect siderophore activity. These mutants were determined to produce sevenfold more SA than K56-2 yet did not produce detectable amounts of ornibactins. These mutants, designated I117 and T10, had a transposon insertion in genes with significant homology to pyoverdine biosynthesis genes of Pseudomonas aeruginosa. I117 contained an insertion in a pvdA homolog, the gene for the enzyme L-ornithine N(5)-oxygenase, which catalyzes the hydroxylation of L-ornithine. Ornibactin synthesis in this mutant was partially restored when the precursor L-N(5)-OH-Orn was added to the culture medium. T10 contained an insertion in a pvdD homolog, which is a peptide synthetase involved in pyoverdine synthesis. beta-Galactosidase activity was iron regulated in both I117 and T10, suggesting that the transposon was inserted downstream of an iron-regulated promoter. Tn5-OT182 contains a lacZ gene that is expressed when inserted downstream of an active promoter. Both I117 and T10 were deficient in uptake of iron complexed to either ornibactins or SA, suggesting that transposon insertions in ornibactin biosynthesis genes also affected other components of the iron transport mechanism. The B. cepacia pvdA homolog was approximately 47% identical and 59% similar to L-ornithine N(5)-oxygenase from P. aeruginosa. Three clones were identified from a K56-2 cosmid library that partially restored ornibactin production, SA production, and SA uptake to parental levels but did not affect the rate of (59)Fe-ornibactin uptake in I117. A chromosomal pvdA deletion mutant was constructed that had a phenotype similar to that of I117 except that it did not hyperproduce SA. The pvdA mutants were less virulent than the parent strain in chronic and acute models of respiratory infection. A functional pvdA gene appears to be required for effective colonization and persistence in B. cepacia lung infections.
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Affiliation(s)
- P A Sokol
- Department of Microbiology and Infectious Diseases, University of Calgary Health Sciences Center, Calgary, Alberta T2N 4N1.
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14
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Suh SJ, Silo-Suh L, Woods DE, Hassett DJ, West SE, Ohman DE. Effect of rpoS mutation on the stress response and expression of virulence factors in Pseudomonas aeruginosa. J Bacteriol 1999; 181:3890-7. [PMID: 10383954 PMCID: PMC93876 DOI: 10.1128/jb.181.13.3890-3897.1999] [Citation(s) in RCA: 253] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The sigma factor RpoS (sigmaS) has been described as a general stress response regulator that controls the expression of genes which confer increased resistance to various stresses in some gram-negative bacteria. To elucidate the role of RpoS in Pseudomonas aeruginosa physiology and pathogenesis, we constructed rpoS mutants in several strains of P. aeruginosa, including PAO1. The PAO1 rpoS mutant was subjected to various environmental stresses, and we compared the resistance phenotype of the mutant to that of the parent. The PAO1 rpoS mutant was slightly more sensitive to carbon starvation than the wild-type strain, but this phenotype was obvious only when the cells were grown in a medium supplemented with glucose as the sole carbon source. In addition, the PAO1 rpoS mutant was hypersensitive to heat shock at 50 degrees C, increased osmolarity, and prolonged exposure to high concentrations of H2O2. In accordance with the hypersensitivity to H2O2, catalase production was 60% lower in the rpoS mutant than in the parent strain. We also assessed the role of RpoS in the production of several exoproducts known to be important for virulence of P. aeruginosa. The rpoS mutant produced 50% less exotoxin A, but it produced only slightly smaller amounts of elastase and LasA protease than the parent strain. The levels of phospholipase C and casein-degrading proteases were unaffected by a mutation in rpoS in PAO1. The rpoS mutation resulted in the increased production of the phenazine antibiotic pyocyanin and the siderophore pyoverdine. This increased pyocyanin production may be responsible for the enhanced virulence of the PAO1 rpoS mutant that was observed in a rat chronic-lung-infection model. In addition, the rpoS mutant displayed an altered twitching-motility phenotype, suggesting that the colonization factors, type IV fimbriae, were affected. Finally, in an alginate-overproducing cystic fibrosis (CF) isolate, FRD1, the rpoS101::aacCI mutation almost completely abolished the production of alginate when the bacterium was grown in a liquid medium. On a solid medium, the FRD1 rpoS mutant produced approximately 70% less alginate than did the wild-type strain. Thus, our data indicate that although some of the functions of RpoS in P. aeruginosa physiology are similar to RpoS functions in other gram-negative bacteria, it also has some functions unique to this bacterium.
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Affiliation(s)
- S J Suh
- Department of Microbiology and Immunology, University of Tennessee, and Veterans Affairs Medical Center, Memphis, Tennessee 38104, USA.
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Darling P, Chan M, Cox AD, Sokol PA. Siderophore production by cystic fibrosis isolates of Burkholderia cepacia. Infect Immun 1998; 66:874-7. [PMID: 9453660 PMCID: PMC107988 DOI: 10.1128/iai.66.2.874-877.1998] [Citation(s) in RCA: 118] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Sixty-one Burkholderia cepacia isolates from patients with cystic fibrosis (CF) and four plant isolates were screened for production of the siderophores salicylic acid (SA), pyochelin, cepabactin, and ornibactins and fingerprinted by a PCR-based randomly amplified polymorphic DNA (RAPD) method. Of the 24 RAPD types determined, 22 (92%) were associated with isolates that produced SA, 21 (87%) were associated with isolates that produced ornibactins, 15 (60%) were associated with isolates that produced pyochelin, and 3 (12%) were associated with isolates that produced cepabactin. Of the 24 RAPD types plus 2 phenotypic variants of types 1 and 9, 3 were associated with isolates that produced all four siderophores, 8 were associated with isolates that produced three siderophores, 12 were associated with isolates that produced two siderophores, and 3 were associated with isolates that produced only one siderophore. These results suggest that the numbers and types of siderophores produced by CF isolates of B. cepacia correlate with RAPD type and that SA and ornibactins are the most prevalent siderophores produced.
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Affiliation(s)
- P Darling
- Department of Microbiology and Infectious Diseases, University of Calgary Health Sciences Centre, Alberta, Canada
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16
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Govan JR, Deretic V. Microbial pathogenesis in cystic fibrosis: mucoid Pseudomonas aeruginosa and Burkholderia cepacia. Microbiol Rev 1996; 60:539-74. [PMID: 8840786 PMCID: PMC239456 DOI: 10.1128/mr.60.3.539-574.1996] [Citation(s) in RCA: 845] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Respiratory infections with Pseudomonas aeruginosa and Burkholderia cepacia play a major role in the pathogenesis of cystic fibrosis (CF). This review summarizes the latest advances in understanding host-pathogen interactions in CF with an emphasis on the role and control of conversion to mucoidy in P. aeruginosa, a phenomenon epitomizing the adaptation of this opportunistic pathogen to the chronic chourse of infection in CF, and on the innate resistance to antibiotics of B. cepacia, person-to-person spread, and sometimes rapidly fatal disease caused by this organism. While understanding the mechanism of conversion to mucoidy in P. aeruginosa has progressed to the point where this phenomenon has evolved into a model system for studying bacterial stress response in microbial pathogenesis, the more recent challenge with B. cepacia, which has emerged as a potent bona fide CF pathogen, is discussed in the context of clinical issues, taxonomy, transmission, and potential modes of pathogenicity.
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Affiliation(s)
- J R Govan
- Department of Medical Microbiology, University of Edinburgh Medical School, Scotland
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17
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McKenney D, Brown KE, Allison DG. Influence of Pseudomonas aeruginosa exoproducts on virulence factor production in Burkholderia cepacia: evidence of interspecies communication. J Bacteriol 1995; 177:6989-92. [PMID: 7592496 PMCID: PMC177571 DOI: 10.1128/jb.177.23.6989-6992.1995] [Citation(s) in RCA: 97] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The effect of concentrated cell-free extracellular material from stationary-phase cultures of Burkholderia cepacia 10661 and Pseudomonas aeruginosa PAO1 on virulence factor production in B. cepacia was assessed. While increasing concentrations of the B. cepacia exoproduct caused a slight increase in siderophore, lipase, and protease production in the producing organism, a significant in productivity was observed for all three virulence factors with the addition of the PAO1 exoproduct. Moreover, the addition of the exoproduct from a strain of P. aeruginosa producing reduced amounts of autoinducer caused only a slightly greater response than that of the control. Both B. cepacia 10661 and P. aeruginosa PAO1, along with two matched clinical isolates of both organisms obtained from a cystic fibrotic patient, were shown to produce variable amounts of three different types of autoinducer. The potential for interspecies signalling in microbial pathogenicity is discussed.
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Affiliation(s)
- D McKenney
- Department of Pharmacy, University of Manchester, England, United Kingdom
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18
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McKenney D, Allison DG. Effects of growth rate and nutrient limitation on virulence factor production in Burkholderia cepacia. J Bacteriol 1995; 177:4140-3. [PMID: 7541788 PMCID: PMC177149 DOI: 10.1128/jb.177.14.4140-4143.1995] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The influence of growth rate and oxygen availability on siderophore, protease, and lipase production in Burkholderia cepacia was assessed for cells grown in a chemostat under iron limitation. Whereas siderophore and protease production increased with growth rate and oxygen yet decreased under oxygen depletion, lipase production demonstrated the opposite trend.
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Affiliation(s)
- D McKenney
- Department of Pharmacy, University of Manchester, England
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19
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Burnie JP, al-Wardi EJ, Williamson P, Matthews RC, Webb K, David T. Defining potential targets for immunotherapy in Burkholderia cepacia infection. FEMS IMMUNOLOGY AND MEDICAL MICROBIOLOGY 1995; 10:157-64. [PMID: 7536517 DOI: 10.1111/j.1574-695x.1995.tb00026.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Burkholderia cepacia has become a serious source of infection in patients with cystic fibrosis. Antibiotic therapy is difficult as the bacteria are intrinsically resistant to most antibiotics. The present study compared the antibody response by immunoblot of 50 negative control sera, 22 patients with cystic fibrosis and no evidence of B. cepacia, 9 clinically well patients with cystic fibrosis colonised by B. cepacia and 5 patients with cystic fibrosis and deteriorating or fatal B. cepacia infection. Nineteen antigenic bands varying in apparent molecular weights from 19 to 170 kDa were identified. Two bands at 19 and 21 kDa were only present when the organism was grown in an iron-deficient medium. The band at 30 kDa was identified as a porin and the possession of IgG antibody carried a statistically significant (P = 0.00003) better prognosis. This antigen was thus a potential target for immunotherapy.
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Affiliation(s)
- J P Burnie
- Department of Medical Microbiology, University of Manchester Medical School, UK
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Nelson JW, Butler SL, Krieg D, Govan JR. Virulence factors of Burkholderia cepacia. FEMS IMMUNOLOGY AND MEDICAL MICROBIOLOGY 1994; 8:89-97. [PMID: 7513590 DOI: 10.1111/j.1574-695x.1994.tb00430.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- J W Nelson
- Department of Medical Microbiology, University Medical School, Edinburgh, Scotland, UK
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21
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Poole K, Neshat S, Krebes K, Heinrichs DE. Cloning and nucleotide sequence analysis of the ferripyoverdine receptor gene fpvA of Pseudomonas aeruginosa. J Bacteriol 1993; 175:4597-604. [PMID: 8335619 PMCID: PMC204910 DOI: 10.1128/jb.175.15.4597-4604.1993] [Citation(s) in RCA: 145] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Pseudomonas aeruginosa K437 lacks the ferripyoverdine receptor and, as a result, grows poorly on an iron-deficient minimal medium supplemented with ethylenediamine-di(o-hydroxyphenylacetic acid) (EDDHA) and pyroverdine. By using a phagemid-based in vivo cloning system, attempts were made to clone the receptor gene by complementing this growth defect. Several recombinant phagemids carrying P. aeruginosa chromosomal DNA which provided for good growth on EDDHA-pyoverdine-containing medium and which concomitantly restored production of the ferripyroverdine receptor in strain K437 were isolated. These phagemids contained a common 4.6-kb SphI fragment which similarly restored production of the receptor in K437. Nucleotide sequencing of the SphI fragment revealed a single large open reading frame, designated fpvA (ferripyoverdine uptake), of 2439 bp. The predicted translation product of fpvA has a molecular mass of 89,395 Da. N-terminal amino acid sequence analysis of the purified ferripyoverdine receptor confirmed fpvA as the receptor gene. Moreover, it indicated that the receptor is initially synthesized as a precursor with a signal sequence of 27 amino acids which is cleaved to yield the mature protein. The deduced FpvA polypeptide exhibited homology to regions shown to be conserved in TonB-dependent receptor proteins. FpvA also shared strong homology (41.3% identity) with the PupA protein of Pseudomonas putida WCS358. This protein is the receptor for the iron-bound form of pseudobactin, a compound structurally very similar to pyoverdine.
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Affiliation(s)
- K Poole
- Department of Microbiology and Immunology, Queen's University, Kingston, Ontario, Canada
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22
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Ankenbauer RG. Cloning of the outer membrane high-affinity Fe(III)-pyochelin receptor of Pseudomonas aeruginosa. J Bacteriol 1992; 174:4401-9. [PMID: 1320609 PMCID: PMC206225 DOI: 10.1128/jb.174.13.4401-4409.1992] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Pseudomonas aeruginosa produces the phenolic siderophore pyochelin under iron-limiting conditions. In this study, an Fe(III)-pyochelin transport-negative (Fpt-) strain, IA613, was isolated and characterized. 55Fe(III)-pyochelin transport assays determined that no Fe(III)-pyochelin associated with the Fpt- IA613 cells while a significant amount associated with KCN-poisoned Fpt+ cells. A P. aeruginosa genomic library was constructed in the IncP cosmid pLAFR1. The genomic library was mobilized into IA613, and a recombinant cosmid, pCC41, which complemented the Fpt- phenotype of IA613, was isolated. pCC41 contained a 28-kb insert of P. aeruginosa DNA, and the Fpt(-)-complementing region was localized to a 3.6-kb BamHI-EcoRI fragment by deletion and subcloning of the insert. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of IA613 revealed that it lacked a 75-kDa outer membrane protein present in Fpt+ strains. IA613 strains bearing plasmid pRML303, which carries the 3.6-kb BamHI-EcoRI fragment of pCC41, expressed the 75-kDa outer membrane protein and demonstrated a 55Fe(III)-pyochelin transport phenotype identical to that of a wild-type Fpt+ strain. Minicell analysis demonstrated that the 3.6-kb BamHI-EcoRI fragment of pCC41 encoded a protein of approximately 75 kDa. The results presented here and in a previous report (D. E. Heinrichs, L. Young, and K. Poole, Infect. Immun. 59:3680-3684, 1991) lead to the conclusion that the 75-kDa outer membrane protein is the high-affinity receptor for Fe(III)-pyochelin in P. aeruginosa.
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Affiliation(s)
- R G Ankenbauer
- Laboratory of Microbial Structure and Function, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, Montana 59840
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23
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Abstract
Eighty-four strains of Pseudomonas pseudomallei isolated from patients with melioidosis were examined for siderophore production. All the strains were shown to produce siderophore both on chrome azurol S agar plates and in liquid medium under iron-deficient conditions. Chemical assays indicated that the siderophore belongs to the hydroxamate class. Addition of iron to the culture medium resulted in increased culture growth with markedly decreased yield of siderophore. Siderophore produced by strain U7 was purified by gel filtration chromatography, and the molecular weight was estimated to be 1,000. When this partially purified siderophore was added to culture medium, it promoted iron uptake by P. pseudomallei in the presence of EDTA and enhanced growth of the organism in the presence of transferrin. We have given this siderophore the trivial name malleobactin.
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Affiliation(s)
- H M Yang
- Department of Microbiology and Infectious Diseases, University of Calgary Health Science Centre, Alberta, Canada
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Abstract
Iron is now recognized as playing a vital role in infection. Not only does it restricted availability in tissue fluids present microbial pathogens with the problem of acquiring sufficient for multiplication in vivo, but it also constitutes a major environmental signal which co-ordinately regulates the expression of a number of virulence and metabolic genes. Progress in understanding the strategies used by pathogens for acquiring iron in vivo, and their responses to iron restriction, is providing a fresh insight into microbial pathogenicity.
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Affiliation(s)
- E Griffiths
- National Institute for Biological Standards and Control, Potters Bar, Hertfordshire, UK
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Cox AD, Wilkinson SG. Structures of the O-specific polymers from the lipopolysaccharides of the reference strains for Pseudomonas cepacia serogroups O3 and O5. Carbohydr Res 1989; 195:123-9. [PMID: 2636041 DOI: 10.1016/0008-6215(89)85095-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The putative O-specific polymers of lipopolysaccharides from two reference strains of Pseudomonas cepacia have been isolated and characterized. Both polymers have disaccharide repeating-units. Structure 1 was established for the O3 polymer, and structure 2 for the O5 polymer. Polymers with the same repeating units have been found previously as the O antigens of other bacteria. ----2)-beta-D-Ribf-(1----4)-alpha-D-GalpNAc-(1---- ----4)-alpha-L-Rhap-(1----3)-beta-D-ManpNAc-(1----
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Affiliation(s)
- A D Cox
- School of Chemistry, The University, Great Britain
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26
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Oxley D, Wilkinson SG. Structure of the O-specific galactan from the lipopolysaccharide of the reference strain for Serratia marcescens serogroup O24. Carbohydr Res 1989; 195:117-22. [PMID: 2699831 DOI: 10.1016/0008-6215(89)85094-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The putative O-specific polysaccharide for Serratia marcescens serogroup O24 is a galactan with a branched, trisaccharide repeating-unit of the structure shown. The structure of the backbone is identical to that of the linear galactans isolated from the reference strains for S. marcescens serogroups O16 and O20, presumably accounting for the serological cross-reactions observed. (Formula: see text)
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Affiliation(s)
- D Oxley
- School of Chemistry, The University, Hull (Great Britain)
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