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Razvi E, DiFrancesco BR, Wasney GA, Morrison ZA, Tam J, Auger A, Baker P, Alnabelseya N, Rich JD, Sivarajah P, Whitfield GB, Harrison JJ, Melnyk RA, Nitz M, Howell PL. Small Molecule Inhibition of an Exopolysaccharide Modification Enzyme is a Viable Strategy To Block Pseudomonas aeruginosa Pel Biofilm Formation. Microbiol Spectr 2023; 11:e0029623. [PMID: 37098898 PMCID: PMC10269871 DOI: 10.1128/spectrum.00296-23] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 04/03/2023] [Indexed: 04/27/2023] Open
Abstract
Biosynthesis of the Pel exopolysaccharide in Pseudomonas aeruginosa requires all seven genes of the pelABCDEFG operon. The periplasmic modification enzyme PelA contains a C-terminal deacetylase domain that is necessary for Pel-dependent biofilm formation. Herein, we show that extracellular Pel is not produced by a P. aeruginosa PelA deacetylase mutant. This positions PelA deacetylase activity as an attractive target to prevent Pel-dependent biofilm formation. Using a high-throughput screen (n = 69,360), we identified 56 compounds that potentially inhibit PelA esterase activity, the first enzymatic step in the deacetylase reaction. A secondary biofilm inhibition assay identified methyl 2-(2-pyridinylmethylene) hydrazinecarbodithioate (SK-017154-O) as a specific Pel-dependent biofilm inhibitor. Structure-activity relationship studies identified the thiocarbazate as a necessary functional group and that the pyridyl ring could be replaced with a phenyl substituent (compound 1). Both SK-017154-O and compound 1 inhibit Pel-dependent biofilm formation in Bacillus cereus ATCC 10987, which has a predicted extracellular PelA deacetylase in its pel operon. Michaelis-Menten kinetics determined SK-017154-O to be a noncompetitive inhibitor of PelA, while compound 1 did not directly inhibit PelA esterase activity. Cytotoxicity assays using human lung fibroblast cells showed that compound 1 is less cytotoxic than SK-017154-O. This work provides proof of concept that biofilm exopolysaccharide modification enzymes are important for biofilm formation and can serve as useful antibiofilm targets. IMPORTANCE Present in more than 500 diverse Gram-negative and 900 Gram-positive organisms, the Pel polysaccharide is one of the most phylogenetically widespread biofilm matrix determinants found to date. Partial de-N-acetylation of this α-1,4 linked N-acetylgalactosamine polymer by the carbohydrate modification enzyme PelA is required for Pel-dependent biofilm formation in Pseudomonas aeruginosa and Bacillus cereus. Given this and our observation that extracellular Pel is not produced by a P. aeruginosa PelA deactylase mutant, we developed an enzyme-based high-throughput screen and identified methyl 2-(2-pyridinylmethylene) hydrazinecarbodithioate (SK-017154-O) and its phenyl derivative as specific Pel-dependent biofilm inhibitors. Michaelis-Menten kinetics revealed SK-017154-O is a noncompetitive inhibitor and that its noncytotoxic, phenyl derivative does not directly inhibit P. aeruginosa PelA esterase activity. We provide proof of concept that exopolysaccharide modification enzymes can be targeted with small molecule inhibitors to block Pel-dependent biofilm development in both Gram-negative and Gram-positive bacteria.
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Affiliation(s)
- Erum Razvi
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | | | - Gregory A. Wasney
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
- The Structural & Biophysical Core Facility, The Hospital for Sick Children, Toronto, Ontario, Canada
| | | | - John Tam
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Anick Auger
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
- SPARC BioCentre, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Perrin Baker
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Noor Alnabelseya
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Jacquelyn D. Rich
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Piyanka Sivarajah
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Gregory B. Whitfield
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Joe J. Harrison
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Roman A. Melnyk
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Mark Nitz
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada
| | - P. Lynne Howell
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
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Variability of <i>pgm</i>‑Region Genes in <i>Yersinia pestis</i> Strains from the Caspian Sandy and Adjacent Plague Foci. PROBLEMS OF PARTICULARLY DANGEROUS INFECTIONS 2023. [DOI: 10.21055/0370-1069-2022-4-57-62] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
The aim of the study was to compare the nucleotide sequences of pgm‑region genes in Yersinia pestis strains isolated on the territory of the Caspian sandy and adjacent plague foci in 1925–2015. Materials and methods. 65 Y. pestis strains from the Caspian sandy and adjacent plague foci were used in the work. DNA isolation was performed using the PureLink Genomic DNA Mini Kit. Whole genome sequencing was conducted in Ion S5 XL System (Thermo Fischer Scientific). Data processing was carried out using Ion Torrent Suite software package 3.4.2 and NewblerGS Assembler 2.6. To compare the obtained sequences with the NCBI GenBank database, the Blast algorithm was used. The phylogenetic analysis was performed according to the data of whole genome SNP analysis based on 1183 identified SNPs. The search for marker SNPs was performed using the Snippy 4.6 program. The phylogenetic tree was constructed using the Maximum Likelihood algorithm, the GTR nucleotide substitution model. Results and discussion. The nucleotide sequences of pgm‑region genes of 65 Y. pestis strains from the Caspian sandy and adjacent plague foci have been assessed. Single nucleotide substitutions have been identified in Y. pestis strains from the Caspian sandy and Kobystan plain-foothill foci in the hmsR, astB, ybtS, ypo1944, ypo1943, ypo1936 genes, as well as a deletion of 5 bp in the ypo1945 gene, which is characteristic of strains of one of the phylogenetic lines of Y. pestis from the foci of Caucasus and Transcaucasia, isolated in 1968–2001. The data obtained can be used to differentiate Y. pestis strains from the Caspian sandy focus, as well as to establish the directions of microevolution of the plague pathogen in this region and adjacent foci.
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Nlp enhances biofilm formation by Yersinia pestis biovar microtus. Microb Pathog 2022; 169:105659. [PMID: 35760284 DOI: 10.1016/j.micpath.2022.105659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 06/21/2022] [Accepted: 06/22/2022] [Indexed: 11/22/2022]
Abstract
Biofilms formed by Yersinia pestis are able to attach to and block flea's proventriculus, which stimulates the transmission of this pathogen from fleas to mammals. In this study, we found that Nlp (YP1143) enhanced biofilm formation by Y. pestis and had regulatory effects on biofilm-associated genes at the transcriptional level. Phenotypic assays, including colony morphology assay, crystal violet staining, and Caenorhabditis elegans biofilm assay, disclosed that Nlp strongly promoted biofilm formation by Y. pestis. Further gene regulation assays showed that Nlp stimulated the expression of hmsHFRS, hmsCDE and hmsB, while had no regulatory effect on the expression of hmsT and hmsP at the transcriptional level. These findings promoted us to gain more understanding of the complex regulatory circuits controlling biofilm formation by Y. pestis.
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Gahlot DK, Wai SN, Erickson DL, Francis MS. Cpx-signalling facilitates Hms-dependent biofilm formation by Yersinia pseudotuberculosis. NPJ Biofilms Microbiomes 2022; 8:13. [PMID: 35351893 PMCID: PMC8964730 DOI: 10.1038/s41522-022-00281-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 02/18/2022] [Indexed: 11/30/2022] Open
Abstract
Bacteria often reside in sessile communities called biofilms, where they adhere to a variety of surfaces and exist as aggregates in a viscous polymeric matrix. Biofilms are resistant to antimicrobial treatments, and are a major contributor to the persistence and chronicity of many bacterial infections. Herein, we determined that the CpxA-CpxR two-component system influenced the ability of enteropathogenic Yersinia pseudotuberculosis to develop biofilms. Mutant bacteria that accumulated the active CpxR~P isoform failed to form biofilms on plastic or on the surface of the Caenorhabditis elegans nematode. A failure to form biofilms on the worm surface prompted their survival when grown on the lawns of Y. pseudotuberculosis. Exopolysaccharide production by the hms loci is the major driver of biofilms formed by Yersinia. We used a number of molecular genetic approaches to demonstrate that active CpxR~P binds directly to the promoter regulatory elements of the hms loci to activate the repressors of hms expression and to repress the activators of hms expression. Consequently, active Cpx-signalling culminated in a loss of exopolysaccharide production. Hence, the development of Y. pseudotuberculosis biofilms on multiple surfaces is controlled by the Cpx-signalling, and at least in part this occurs through repressive effects on the Hms-dependent exopolysaccharide production.
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Inactivation of the sfgtr4 Gene of Shigella flexneri Induces Biofilm Formation and Affects Bacterial Pathogenicity. Microorganisms 2020; 8:microorganisms8060841. [PMID: 32512756 PMCID: PMC7355660 DOI: 10.3390/microorganisms8060841] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 05/08/2020] [Accepted: 05/21/2020] [Indexed: 01/08/2023] Open
Abstract
Biofilm formation is a significant cause for the environmental persistence of foodborne pathogens. This phenomenon remains misunderstood in Shigellaflexneri whose pathogenicity is mainly associated with the virulence plasmid pWR100. Sequence analysis of the latter predicts a putative lipopolysaccharides (LPS) glycosyltransferase (Gtr) encoded by Sfgtr4, which is the second gene of the SfpgdA-orf186-virK-msbB2 locus. We demonstrated here that purified SfGtr4 exhibited a Gtr activity in vitro by transferring glucose to lipid A. To establish the role of SfGtr4 in virulence, we generated a Sfgtr4 mutant and assessed its phenotype in vitro. Sfgtr4 mutant significantly reduced HeLa cells invasion without impairing type III effectors secretion, increased susceptibility to lysozyme degradation, and enhanced bacterial killing by polymorphonuclear neutrophils (PMNs). SfGtr4 is related to proteins required in biofilm formation. We established conditions whereby wild-type Shigella formed biofilm and revealed that its appearance was accelerated by the Sfgtr4 mutant. Additional phenotypical analysis revealed that single SfpdgA and double SfpgdA-Sfgtr4 mutants behaved similarly to Sfgtr4 mutant. Furthermore, a molecular interaction between SfGtr4 and SfPgdA was identified. In summary, the dual contribution of SfGtr4 and SfPgdA to the pathogenicity and the regulation biofilm formation by S. flexneri was demonstrated here.
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Liu L, Zheng S. Transcriptional regulation of Yersinia pestis biofilm formation. Microb Pathog 2019; 131:212-217. [PMID: 30980880 DOI: 10.1016/j.micpath.2019.04.011] [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: 11/09/2018] [Revised: 04/08/2019] [Indexed: 01/27/2023]
Abstract
Yersinia pestis, the causative agent of plague, is transmitted primarily by infected fleas in nature. Y. pestis can produce biofilms that block flea's proventriculus and promote flea-borne transmission. Transcriptional regulation of Y. pestis biofilm formation plays an important role in the response to complex changes in environments, including temperature, pH, oxidative stress, and restrictive nutrition conditions, and contributes to Y. pestis growth, reproduction, transmission, and pathogenesis. A set of transcriptional regulators involved in Y. pestis biofilm production simultaneously controls a variety of biological functions and physiological pathways. Interactions between these regulators contribute to the development of Y. pestis gene regulatory networks, which are helpful for a quick response to complex environmental changes and better survival. The roles of crucial factors and regulators involved in response to complex environmental signals and Y. pestis biofilm formation as well as the precise gene regulatory networks are discussed in this review, which will give a better understanding of the complicated mechanisms of transcriptional regulation in Y. pestis biofilm formation.
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Affiliation(s)
- Lei Liu
- Department of Transfusion, General Hospital of Central Theater Command, Wuhan, 430070, Hubei, China; State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, 100071, China
| | - Shangen Zheng
- Department of Transfusion, General Hospital of Central Theater Command, Wuhan, 430070, Hubei, China.
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Ostapska H, Howell PL, Sheppard DC. Deacetylated microbial biofilm exopolysaccharides: It pays to be positive. PLoS Pathog 2018; 14:e1007411. [PMID: 30589915 PMCID: PMC6307706 DOI: 10.1371/journal.ppat.1007411] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Affiliation(s)
- Hanna Ostapska
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
- Infectious Diseases in Global Health Program, McGill University Health Centre, Montreal, Quebec, Canada
| | - P. Lynne Howell
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
- * E-mail: (PLH); (DCS)
| | - Donald C. Sheppard
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
- Infectious Diseases in Global Health Program, McGill University Health Centre, Montreal, Quebec, Canada
- Department of Medicine, McGill University, Montreal, Quebec, Canada
- * E-mail: (PLH); (DCS)
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8
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Schachterle JK, Stewart RM, Schachterle MB, Calder JT, Kang H, Prince JT, Erickson DL. Yersinia pseudotuberculosis BarA-UvrY Two-Component Regulatory System Represses Biofilms via CsrB. Front Cell Infect Microbiol 2018; 8:323. [PMID: 30280093 PMCID: PMC6153318 DOI: 10.3389/fcimb.2018.00323] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 08/24/2018] [Indexed: 01/07/2023] Open
Abstract
The formation of biofilms by Yersinia pseudotuberculosis (Yptb) and Y. pestis requires the hmsHFRS genes, which direct production of a polysaccharide extracellular matrix (Hms-ECM). Despite possessing identical hmsHFRS sequences, Yptb produces much less Hms-ECM than Y. pestis. The regulatory influences that control Yptb Hms-ECM production and biofilm formation are not fully understood. In this study, negative regulators of biofilm production in Yptb were identified. Inactivation of the BarA/UvrY two-component system or the CsrB regulatory RNA increased binding of Congo Red dye, which correlates with extracellular polysaccharide production. These mutants also produced biofilms that were substantially more cohesive than the wild type strain. Disruption of uvrY was not sufficient for Yptb to cause proventricular blockage during infection of Xenopsylla cheopis fleas. However, this strain was less acutely toxic toward fleas than wild type Yptb. Flow cytometry measurements of lectin binding indicated that Yptb BarA/UvrY/CsrB mutants may produce higher levels of other carbohydrates in addition to poly-GlcNAc Hms-ECM. In an effort to characterize the relevant downstream targets of the BarA/UvrY system, we conducted a proteomic analysis to identify proteins with lower abundance in the csrB::Tn5 mutant strain. Urease subunit proteins were less abundant and urease enzymatic activity was lower, which likely reduced toxicity toward fleas. Loss of CsrB impacted expression of several potential regulatory proteins that may influence biofilms, including the RcsB regulator. Overexpression of CsrB did not alter the Congo-red binding phenotype of an rcsB::Tn5 mutant, suggesting that the effect of CsrB on biofilms may require RcsB. These results underscore the regulatory and compositional differences between Yptb and Y. pestis biofilms. By activating CsrB expression, the Yptb BarA/UvrY two-component system has pleiotropic effects that impact biofilm production and stability.
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Affiliation(s)
- Jeffrey K Schachterle
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT, United States
| | - Ryan M Stewart
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT, United States
| | - M Brett Schachterle
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT, United States
| | - Joshua T Calder
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT, United States
| | - Huan Kang
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, United States
| | - John T Prince
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, United States
| | - David L Erickson
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT, United States
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9
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Little DJ, Pfoh R, Le Mauff F, Bamford NC, Notte C, Baker P, Guragain M, Robinson H, Pier GB, Nitz M, Deora R, Sheppard DC, Howell PL. PgaB orthologues contain a glycoside hydrolase domain that cleaves deacetylated poly-β(1,6)-N-acetylglucosamine and can disrupt bacterial biofilms. PLoS Pathog 2018; 14:e1006998. [PMID: 29684093 PMCID: PMC5933820 DOI: 10.1371/journal.ppat.1006998] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 05/03/2018] [Accepted: 03/29/2018] [Indexed: 11/24/2022] Open
Abstract
Poly-β(1,6)-N-acetyl-D-glucosamine (PNAG) is a major biofilm component of many pathogenic bacteria. The production, modification, and export of PNAG in Escherichia coli and Bordetella species require the protein products encoded by the pgaABCD operon. PgaB is a two-domain periplasmic protein that contains an N-terminal deacetylase domain and a C-terminal PNAG binding domain that is critical for export. However, the exact function of the PgaB C-terminal domain remains unclear. Herein, we show that the C-terminal domains of Bordetella bronchiseptica PgaB (PgaBBb) and E. coli PgaB (PgaBEc) function as glycoside hydrolases. These enzymes hydrolyze purified deacetylated PNAG (dPNAG) from Staphylococcus aureus, disrupt PNAG-dependent biofilms formed by Bordetella pertussis, Staphylococcus carnosus, Staphylococcus epidermidis, and E. coli, and potentiate bacterial killing by gentamicin. Furthermore, we found that PgaBBb was only able to hydrolyze PNAG produced in situ by the E. coli PgaCD synthase complex when an active deacetylase domain was present. Mass spectrometry analysis of the PgaB-hydrolyzed dPNAG substrate showed a GlcN-GlcNAc-GlcNAc motif at the new reducing end of detected fragments. Our 1.76 Å structure of the C-terminal domain of PgaBBb reveals a central cavity within an elongated surface groove that appears ideally suited to recognize the GlcN-GlcNAc-GlcNAc motif. The structure, in conjunction with molecular modeling and site directed mutagenesis led to the identification of the dPNAG binding subsites and D474 as the probable catalytic acid. This work expands the role of PgaB within the PNAG biosynthesis machinery, defines a new glycoside hydrolase family GH153, and identifies PgaB as a possible therapeutic agent for treating PNAG-dependent biofilm infections. From plaque on teeth to infections in the lungs of cystic fibrosis patients, biofilms are a serious health concern and difficult to eradicate. One of the key building blocks involved in biofilm formation are polymeric sugar compounds that are secreted by the bacteria. Our work focuses on the biopolymer poly-β(1,6)-N-acetyl-D-glucosamine (PNAG), which is produced by numerous pathogenic organisms. Deacetylation of PNAG by the N-terminal domain of PgaB is a critical step in polymer maturation and is required for the formation of robust biofilms. Herein, we show that the C-terminal domain of PgaB is a glycoside hydrolase active on partially deacetylated PNAG, and that the enzyme disrupts PNAG-dependent biofilms and potentiates killing by antibiotics. Only deacetylated PNAG could be cleaved, suggesting that PgaB deacetylates and hydrolyses the polymer in sequential order. Analyzing the chemical structure of the cleaved dPNAG fragments revealed a distinct motif of sugar units. Structural and functional studies identify key amino acids positioned in an elongated polymer-binding groove that potentially recognize the sugar motif during cleavage. Our study provides further insight into the mechanism of periplasmic PNAG modification, and suggests PgaB could be utilized as a therapeutic agent to eliminate biofilms.
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Affiliation(s)
- Dustin J Little
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Roland Pfoh
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON, Canada
| | - François Le Mauff
- Departments of Medicine and of Microbiology and Immunology, McGill University, Montréal, QC, Canada.,Infectious Diseases and Immunity in Global Health Program, Research Institute of the McGill University Health Centre, Montréal, QC, Canada
| | - Natalie C Bamford
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Christina Notte
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON, Canada
| | - Perrin Baker
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON, Canada
| | - Manita Guragain
- Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, NC, United States of America.,Department of Microbial Infection and Immunity, The Ohio State University Wexner Medical Center, Columbus, OH, United States of America
| | - Howard Robinson
- Photon Sciences Division, Brookhaven National Laboratory, Upton, NY, United States of America
| | - Gerald B Pier
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States of America
| | - Mark Nitz
- Department of Chemistry, University of Toronto, Toronto, ON, Canada
| | - Rajendar Deora
- Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, NC, United States of America.,Department of Microbial Infection and Immunity, The Ohio State University Wexner Medical Center, Columbus, OH, United States of America
| | - Donald C Sheppard
- Departments of Medicine and of Microbiology and Immunology, McGill University, Montréal, QC, Canada.,Infectious Diseases and Immunity in Global Health Program, Research Institute of the McGill University Health Centre, Montréal, QC, Canada
| | - P Lynne Howell
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada
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Liu L, Fang H, Yang H, Zhang Y, Han Y, Zhou D, Yang R. Reciprocal regulation of Yersinia pestis biofilm formation and virulence by RovM and RovA. Open Biol 2016; 6:rsob.150198. [PMID: 26984293 PMCID: PMC4821237 DOI: 10.1098/rsob.150198] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
RovA is known to enhance Yersinia pestis virulence by directly upregulating the psa loci. This work presents a complex gene regulatory paradigm involving the reciprocal regulatory action of RovM and RovA on the expression of biofilm and virulence genes as well as on their own genes. RovM and RovA enhance and inhibit Y. pestis biofilm production, respectively, whereas RovM represses virulence in mice. RovM directly stimulates the transcription of hmsT, hmsCDE and rovM, while indirectly enhancing hmsHFRS transcription. It also indirectly represses hmsP transcription. By contrast, RovA directly represses hmsT transcription and indirectly inhibits waaAE-coaD transcription, while RovM inhibits psaABC and psaEF transcription by directly repressing rovA transcription. rovM expression is significantly upregulated at 26°C (the temperature of the flea gut) relative to 37°C (the warm-blooded host temperature). We speculate that upregulation of rovM together with downregulation of rovA in the flea gut would promote Y. pestis biofilm formation while inhibiting virulence gene expression, leading to a more transmissible infection of this pathogen in fleas. Once the bacterium shifts to a lifestyle in the warm-blooded hosts, inhibited RovM production accompanied by recovered RovA synthesis would encourage virulence factor production and inhibit biofilm gene expression.
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Affiliation(s)
- Lei Liu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, People's Republic of China
| | - Haihong Fang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, People's Republic of China
| | - Huiying Yang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, People's Republic of China
| | - Yiquan Zhang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, People's Republic of China School of Medicine, Jiangsu University, Zhenjiang 212013, Jiangsu, People's Republic of China
| | - Yanping Han
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, People's Republic of China
| | - Dongsheng Zhou
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, People's Republic of China
| | - Ruifu Yang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, People's Republic of China
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Liu L, Fang H, Yang H, Zhang Y, Han Y, Zhou D, Yang R. CRP Is an Activator of Yersinia pestis Biofilm Formation that Operates via a Mechanism Involving gmhA and waaAE-coaD. Front Microbiol 2016; 7:295. [PMID: 27014218 PMCID: PMC4782182 DOI: 10.3389/fmicb.2016.00295] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 02/23/2016] [Indexed: 01/28/2023] Open
Abstract
gmhA encodes a phosphoheptose isomerase that catalyzes the biosynthesis of heptose, a conserved component of lipopolysaccharide (LPS). GmhA plays an important role in Yersinia pestis biofilm blockage in the flea gut. waaA, waaE, and coaD constitute a three-gene operon waaAE-coaD in Y. pestis. waaA encodes a transferase that is responsible for binding lipid-A to the core oligosaccharide of LPS. WaaA is a key determinant in Y. pestis biofilm formation, and the waaA expression is positively regulated by the two-component regulatory system PhoP/PhoQ. WaaE is involved in LPS modification and is necessary for Y. pestis biofilm production. In this study, the biofilm-related phenotypic assays indicate that the global regulator CRP stimulates Y. pestis biofilm formation in vitro and on nematodes, while it has no regulatory effect on the biosynthesis of the biofilm-signaling molecular 3',5'-cyclic diguanosine monophosphate. Further gene regulation experiments disclose that CRP does not regulate the hms genes at the transcriptional level but directly promotes the gmhA transcription and indirectly activates the waaAE-coaD transcription through directly acting on phoPQ-YPO1632. Thus, it is speculated that CRP-mediated carbon catabolite regulation of Y. pestis biofilm formation depends on the CRP-dependent carbon source metabolic pathways of the biosynthesis, modification, and transportation of biofilm exopolysaccharide.
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Affiliation(s)
- Lei Liu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology Beijing, China
| | - Haihong Fang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology Beijing, China
| | - Huiying Yang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology Beijing, China
| | - Yiquan Zhang
- Department of Biochemistry, School of Medicine, Jiangsu University Zhenjiang, China
| | - Yanping Han
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology Beijing, China
| | - Dongsheng Zhou
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology Beijing, China
| | - Ruifu Yang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology Beijing, China
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Whitfield GB, Marmont LS, Howell PL. Enzymatic modifications of exopolysaccharides enhance bacterial persistence. Front Microbiol 2015; 6:471. [PMID: 26029200 PMCID: PMC4432689 DOI: 10.3389/fmicb.2015.00471] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 04/29/2015] [Indexed: 12/25/2022] Open
Abstract
Biofilms are surface-attached communities of bacterial cells embedded in a self-produced matrix that are found ubiquitously in nature. The biofilm matrix is composed of various extracellular polymeric substances, which confer advantages to the encapsulated bacteria by protecting them from eradication. The matrix composition varies between species and is dependent on the environmental niche that the bacteria inhabit. Exopolysaccharides (EPS) play a variety of important roles in biofilm formation in numerous bacterial species. The ability of bacteria to thrive in a broad range of environmental settings is reflected in part by the structural diversity of the EPS produced both within individual bacterial strains as well as by different species. This variability is achieved through polymerization of distinct sugar moieties into homo- or hetero-polymers, as well as post-polymerization modification of the polysaccharide. Specific enzymes that are unique to the production of each polymer can transfer or remove non-carbohydrate moieties, or in other cases, epimerize the sugar units. These modifications alter the physicochemical properties of the polymer, which in turn can affect bacterial pathogenicity, virulence, and environmental adaptability. Herein, we review the diversity of modifications that the EPS alginate, the Pel polysaccharide, Vibrio polysaccharide, cepacian, glycosaminoglycans, and poly-N-acetyl-glucosamine undergo during biosynthesis. These are EPS produced by human pathogenic bacteria for which studies have begun to unravel the effect modifications have on their physicochemical and biological properties. The biological advantages these polymer modifications confer to the bacteria that produce them will be discussed. The expanding list of identified modifications will allow future efforts to focus on linking these modifications to specific biosynthetic genes and biofilm phenotypes.
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Affiliation(s)
- Gregory B Whitfield
- Program in Molecular Structure and Function, Research Institute, The Hospital for Sick Children Toronto, ON, Canada ; Department of Biochemistry, Faculty of Medicine, University of Toronto Toronto, ON, Canada
| | - Lindsey S Marmont
- Program in Molecular Structure and Function, Research Institute, The Hospital for Sick Children Toronto, ON, Canada ; Department of Biochemistry, Faculty of Medicine, University of Toronto Toronto, ON, Canada
| | - P Lynne Howell
- Program in Molecular Structure and Function, Research Institute, The Hospital for Sick Children Toronto, ON, Canada ; Department of Biochemistry, Faculty of Medicine, University of Toronto Toronto, ON, Canada
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Fang N, Yang H, Fang H, Liu L, Zhang Y, Wang L, Han Y, Zhou D, Yang R. RcsAB is a major repressor of Yersinia biofilm development through directly acting on hmsCDE, hmsT, and hmsHFRS. Sci Rep 2015; 5:9566. [PMID: 25828910 PMCID: PMC4381331 DOI: 10.1038/srep09566] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Accepted: 03/11/2015] [Indexed: 02/04/2023] Open
Abstract
Biofilm formation in flea gut is important for flea-borne transmission of Yersinia pestis. There are enhancing factors (HmsHFRS, HmsCDE, and HmsT) and inhibiting one (HmsP) for Yersinia pestis biofilm formation. The RcsAB regulatory complex acts as a repressor of Yesinia biofilm formation, and adaptive pseudogenization of rcsA promotes Y. pestis to evolve the ability of biofilm formation in fleas. In this study, we constructed a set of isogenic strains of Y. pestis biovar Microtus, namely WT (RscB+ and RcsA-), c-rcsA (RscB+ and RcsA+), ΔrcsB (RscB- and RcsA-), and ΔrcsB/c-rcsA (RscB- and RcsA+). The phenotypic assays confirmed that RcsB alone (but not RcsA alone) had an inhibiting effect on biofilm/c-di-GMP production whereas assistance of RcsA to RcsB greatly enhanced this inhibiting effect. Further gene regulation experiments showed that RcsB in assistance of RcsA tightly bound to corresponding promoter-proximal regions to achieve transcriptional repression of hmsCDE, hmsT and hmsHFRS and, meanwhile, RcsAB positively regulated hmsP most likely in an indirect manner. Data presented here disclose that pseudogenization of rcsA leads to dramatic remodeling of RcsAB-dependent hms gene expression between Y. pestis and its progenitor Y. pseudotuberculosis, enabling potent production of Y. pestis biofilms in fleas.
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Affiliation(s)
- Nan Fang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Huiying Yang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Haihong Fang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Lei Liu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Yiquan Zhang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Li Wang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Yanping Han
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Dongsheng Zhou
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Ruifu Yang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
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Modification and periplasmic translocation of the biofilm exopolysaccharide poly-β-1,6-N-acetyl-D-glucosamine. Proc Natl Acad Sci U S A 2014; 111:11013-8. [PMID: 24994902 DOI: 10.1073/pnas.1406388111] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Poly-β-1,6-N-acetyl-D-glucosamine (PNAG) is an exopolysaccharide produced by a wide variety of medically important bacteria. Polyglucosamine subunit B (PgaB) is responsible for the de-N-acetylation of PNAG, a process required for polymer export and biofilm formation. PgaB is located in the periplasm and likely bridges the inner membrane synthesis and outer membrane export machinery. Here, we present structural, functional, and molecular simulation data that suggest PgaB associates with PNAG continuously during periplasmic transport. We show that the association of PgaB's N- and C-terminal domains forms a cleft required for the binding and de-N-acetylation of PNAG. Molecular dynamics (MD) simulations of PgaB show a binding preference for N-acetylglucosamine (GlcNAc) to the N-terminal domain and glucosammonium to the C-terminal domain. Continuous ligand binding density is observed that extends around PgaB from the N-terminal domain active site to an electronegative groove on the C-terminal domain that would allow for a processive mechanism. PgaB's C-terminal domain (PgaB310-672) directly binds PNAG oligomers with dissociation constants of ∼1-3 mM, and the structures of PgaB310-672 in complex with β-1,6-(GlcNAc)6, GlcNAc, and glucosamine reveal a unique binding mode suitable for interaction with de-N-acetylated PNAG (dPNAG). Furthermore, PgaB310-672 contains a β-hairpin loop (βHL) important for binding PNAG that was disordered in previous PgaB42-655 structures and is highly dynamic in the MD simulations. We propose that conformational changes in PgaB310-672 mediated by the βHL on binding of PNAG/dPNAG play an important role in the targeting of the polymer for export and its release.
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Bobrov AG, Kirillina O, Vadyvaloo V, Koestler BJ, Hinz AK, Mack D, Waters CM, Perry RD. The Yersinia pestis HmsCDE regulatory system is essential for blockage of the oriental rat flea (Xenopsylla cheopis), a classic plague vector. Environ Microbiol 2014; 17:947-59. [PMID: 25586342 DOI: 10.1111/1462-2920.12419] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 01/22/2014] [Accepted: 01/29/2014] [Indexed: 01/04/2023]
Abstract
The second messenger molecule cyclic diguanylate is essential for Yersinia pestis biofilm formation that is important for blockage-dependent plague transmission from fleas to mammals. Two diguanylate cyclases (DGCs) HmsT and Y3730 (HmsD) are responsible for biofilm formation in vitro and biofilm-dependent blockage in the oriental rat flea Xenopsylla cheopis respectively. Here, we have identified a tripartite signalling system encoded by the y3729-y3731 operon that is responsible for regulation of biofilm formation in different environments. We present genetic evidence that a putative inner membrane-anchored protein with a large periplasmic domain Y3729 (HmsC) inhibits HmsD DGC activity in vitro while an outer membrane Pal-like putative lipoprotein Y3731 (HmsE) counteracts HmsC to activate HmsD in the gut of X. cheopis. We propose that HmsE is a critical element in the transduction of environmental signal(s) required for HmsD-dependent biofilm formation.
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Affiliation(s)
- Alexander G Bobrov
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky, Lexington, KY, USA
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16
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YfbA, a Yersinia pestis regulator required for colonization and biofilm formation in the gut of cat fleas. J Bacteriol 2014; 196:1165-73. [PMID: 24391055 DOI: 10.1128/jb.01187-13] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
For transmission to new hosts, Yersinia pestis, the causative agent of plague, replicates as biofilm in the foregut of fleas that feed on plague-infected animals or humans. Y. pestis biofilm formation has been studied in the rat flea; however, little is known about the cat flea, a species that may bridge zoonotic and anthroponotic plague cycles. Here, we show that Y. pestis infects and replicates as a biofilm in the foregut of cat fleas in a manner requiring hmsFR, two determinants for extracellular biofilm matrix. Examining a library of transposon insertion mutants, we identified the LysR-type transcriptional regulator YfbA, which is essential for Y. pestis colonization and biofilm formation in cat fleas.
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17
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Lawal A, Kirtley ML, van Lier CJ, Erova TE, Kozlova EV, Sha J, Chopra AK, Rosenzweig JA. The effects of modeled microgravity on growth kinetics, antibiotic susceptibility, cold growth, and the virulence potential of a Yersinia pestis ymoA-deficient mutant and its isogenic parental strain. ASTROBIOLOGY 2013; 13:821-32. [PMID: 23988036 PMCID: PMC3779001 DOI: 10.1089/ast.2013.0968] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Accepted: 06/09/2013] [Indexed: 06/02/2023]
Abstract
Previously, we reported that there was no enhancement in the virulence potential (as measured by cell culture infections) of the bacterial pathogen Yersinia pestis (YP) following modeled microgravity/clinorotation growth. We have now further characterized the effects of clinorotation (CR) on YP growth kinetics, antibiotic sensitivity, cold growth, and YP's virulence potential in a murine model of infection. Surprisingly, none of the aforementioned phenotypes were altered. To better understand why CR did not enhance YP's virulence potential as it did for other bacterial pathogens, a YP ΔymoA isogenic mutant in the KIM/D27 background strain that is unable to produce the histone-like YmoA protein and influences DNA topography was used in both cell culture and murine models of infection. YmoA represses type three secretion system (T3SS) virulence gene expression in the yersiniae. Similar to our CR-grown parental YP strain data, the CR-grown ΔymoA mutant induced reduced HeLa cell cytotoxicity with concomitantly decreased Yersinia outer protein E (YopE) and low calcium response V (LcrV) antigen production and secretion. Important, however, were our findings that, although no significant differences were observed in survival of mice infected intraperitoneally with either normal gravity (NG)- or CR-grown parental YP, the ΔymoA mutant induced significantly more mortality in infected mice than did the parental strain following CR growth. Taken together, our data demonstrate that CR did enhance the virulence potential of the YP ΔymoA mutant in a murine infection model (relative to the CR-grown parental strain), despite inducing less HeLa cell rounding in our cell culture infection assay due to reduced T3SS activity. Therefore, CR, which induces a unique type of bacterial stress, might be enhancing YP's virulence potential in vivo through a T3SS-independent mechanism when the histone-like YmoA protein is absent.
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Affiliation(s)
- Abidat Lawal
- Department of Biology, Department of Environmental and Interdisciplinary Sciences, Center for Bionanotechnology and Environmental Research (CBER), Texas Southern University, Houston, Texas
| | - Michelle L. Kirtley
- Department of Microbiology and Immunology, Sealy Center for Vaccine Development, Institute of Human Infections and Immunity, and the Galveston National Laboratory, University of Texas Medical Branch, Galveston, Texas
| | - Christina J. van Lier
- Department of Microbiology and Immunology, Sealy Center for Vaccine Development, Institute of Human Infections and Immunity, and the Galveston National Laboratory, University of Texas Medical Branch, Galveston, Texas
| | - Tatiana E. Erova
- Department of Microbiology and Immunology, Sealy Center for Vaccine Development, Institute of Human Infections and Immunity, and the Galveston National Laboratory, University of Texas Medical Branch, Galveston, Texas
| | - Elena V. Kozlova
- Department of Microbiology and Immunology, Sealy Center for Vaccine Development, Institute of Human Infections and Immunity, and the Galveston National Laboratory, University of Texas Medical Branch, Galveston, Texas
| | - Jian Sha
- Department of Microbiology and Immunology, Sealy Center for Vaccine Development, Institute of Human Infections and Immunity, and the Galveston National Laboratory, University of Texas Medical Branch, Galveston, Texas
| | - Ashok K. Chopra
- Department of Microbiology and Immunology, Sealy Center for Vaccine Development, Institute of Human Infections and Immunity, and the Galveston National Laboratory, University of Texas Medical Branch, Galveston, Texas
| | - Jason A. Rosenzweig
- Department of Biology, Department of Environmental and Interdisciplinary Sciences, Center for Bionanotechnology and Environmental Research (CBER), Texas Southern University, Houston, Texas
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Yuan B, Cheng A, Wang M. Polysaccharide export outer membrane proteins in Gram-negative bacteria. Future Microbiol 2013; 8:525-35. [DOI: 10.2217/fmb.13.13] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Polysaccharide export outer membrane proteins of Gram-negative bacteria are involved in the export of polysaccharides across the outer membrane. The mechanisms of polysaccharide export across the outer membrane in Gram-negative bacteria are not yet completely clear. However, the mechanisms of polysaccharide assembly in Escherichia coli have been intensively investigated. Here, we mainly review the current understanding of the assembly mechanisms of group 1 capsular polysaccharide, group 2 capsular polysaccharide and lipopolysaccharide of E. coli, and the current structures and interactions of some polysaccharide export outer membrane proteins with other proteins involved in polysaccharide export in Gram-negative bacteria. In addition, LptD may be targeted by peptidomimetic antibiotics in Gram-negative bacteria. We also give insights into the directions of future research regarding the mechanisms of polysaccharide export.
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Affiliation(s)
- Biao Yuan
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, China.
| | - Anchun Cheng
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, China
- Avian Disease Research Center, College of Veterinary Medicine of Sichuan Agricultural University, 46 Xinkang Road, Ya’an, Sichuan 625014, China
- Key Laboratory of Animal Disease & Human Health of Sichuan Province, Sichuan Agricultural University, Wenjiang, Chengdu city, Sichuan 611130, China
| | - Mingshu Wang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, China
- Avian Disease Research Center, College of Veterinary Medicine of Sichuan Agricultural University, 46 Xinkang Road, Ya’an, Sichuan 625014, China
- Key Laboratory of Animal Disease & Human Health of Sichuan Province, Sichuan Agricultural University, Wenjiang, Chengdu city, Sichuan 611130, China
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19
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PelA deacetylase activity is required for Pel polysaccharide synthesis in Pseudomonas aeruginosa. J Bacteriol 2013; 195:2329-39. [PMID: 23504011 DOI: 10.1128/jb.02150-12] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Pel polysaccharide serves as an intercellular adhesin for the formation and maintenance of biofilms in the opportunistic pathogen Pseudomonas aeruginosa. Pel biosynthesis requires the products of a seven-gene operon, pelA-pelG, all of which are necessary for Pel-dependent biofilm formation and Pel-related phenotypes. One of the genes, pelA, encodes a protein with a predicted polysaccharide deacetylase domain. In this work, the role of the putative deacetylase domain in Pel production was examined. We first established that purified recombinant PelA hydrolyzed the pseudosubstrate p-nitrophenyl acetate in vitro, and site-specific mutations of predicted deacetylase active-site residues reduced activity greater than 10-fold. Additionally, these mutants were deficient in Pel-dependent biofilm formation and wrinkly colony morphology in vivo. Subcellular fractionation experiments demonstrate that PelA localizes to both the membrane and periplasmic fractions. Finally, antiserum against the Pel polysaccharide was generated, and PelA deacetylase mutants do not produce Pel-reactive material. Taken together, these results suggest that the deacetylase activity of PelA is important for the production of the Pel polysaccharide.
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20
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Sun F, Gao H, Zhang Y, Wang L, Fang N, Tan Y, Guo Z, Xia P, Zhou D, Yang R. Fur is a repressor of biofilm formation in Yersinia pestis. PLoS One 2012; 7:e52392. [PMID: 23285021 PMCID: PMC3528687 DOI: 10.1371/journal.pone.0052392] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Accepted: 11/13/2012] [Indexed: 11/29/2022] Open
Abstract
Background Yersinia pestis synthesizes the attached biofilms in the flea proventriculus, which is important for the transmission of this pathogen by fleas. The hmsHFRS operons is responsible for the synthesis of exopolysaccharide (the major component of biofilm matrix), which is activated by the signaling molecule 3′, 5′-cyclic diguanylic acid (c-di-GMP) synthesized by the only two diguanylate cyclases HmsT, and YPO0449 (located in a putative operonYPO0450-0448). Methodology/Principal Findings The phenotypic assays indicated that the transcriptional regulator Fur inhibited the Y. pestis biofilm production in vitro and on nematode. Two distinct Fur box-like sequences were predicted within the promoter-proximal region of hmsT, suggesting that hmsT might be a direct Fur target. The subsequent primer extension, LacZ fusion, electrophoretic mobility shift, and DNase I footprinting assays disclosed that Fur specifically bound to the hmsT promoter-proximal region for repressing the hmsT transcription. In contrast, Fur had no regulatory effect on hmsHFRS and YPO0450-0448 at the transcriptional level. The detection of intracellular c-di-GMP levels revealed that Fur inhibited the c-di-GMP production. Conclusions/Significance Y. pestis Fur inhibits the c-di-GMP production through directly repressing the transcription of hmsT, and thus it acts as a repressor of biofilm formation. Since the relevant genetic contents for fur, hmsT, hmsHFRS, and YPO0450-0448 are extremely conserved between Y. pestis and typical Y. pseudotuberculosis, the above regulatory mechanisms can be applied to Y. pseudotuberculosis.
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Affiliation(s)
- Fengjun Sun
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
- Department of Pharmacy, Southwest Hospital, the Third Military Medical University, Chongqing, China
| | - He Gao
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Centre for Disease Control and Prevention, Beijing, China
| | - Yiquan Zhang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Li Wang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Nan Fang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Yafang Tan
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Zhaobiao Guo
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Peiyuan Xia
- Department of Pharmacy, Southwest Hospital, the Third Military Medical University, Chongqing, China
- * E-mail: (PX); (DZ); (RY)
| | - Dongsheng Zhou
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
- * E-mail: (PX); (DZ); (RY)
| | - Ruifu Yang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
- * E-mail: (PX); (DZ); (RY)
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21
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Allosteric activation of exopolysaccharide synthesis through cyclic di-GMP-stimulated protein-protein interaction. EMBO J 2012. [PMID: 23202856 DOI: 10.1038/emboj.2012.315] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
In many bacterial pathogens, the second messenger c-di-GMP stimulates the production of an exopolysaccharide (EPS) matrix to shield bacteria from assaults of the immune system. How c-di-GMP induces EPS biogenesis is largely unknown. Here, we show that c-di-GMP allosterically activates the synthesis of poly-β-1,6-N-acetylglucosamine (poly-GlcNAc), a major extracellular matrix component of Escherichia coli biofilms. C-di-GMP binds directly to both PgaC and PgaD, the two inner membrane components of the poly-GlcNAc synthesis machinery to stimulate their glycosyltransferase activity. We demonstrate that the PgaCD machinery is a novel type c-di-GMP receptor, where ligand binding to two proteins stabilizes their interaction and promotes enzyme activity. This is the first example of a c-di-GMP-mediated process that relies on protein-protein interaction. At low c-di-GMP concentrations, PgaD fails to interact with PgaC and is rapidly degraded. Thus, when cells experience a c-di-GMP trough, PgaD turnover facilitates the irreversible inactivation of the Pga machinery, thereby temporarily uncoupling it from c-di-GMP signalling. These data uncover a mechanism of c-di-GMP-mediated EPS control and provide a frame for c-di-GMP signalling specificity in pathogenic bacteria.
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22
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Mashimo C, Kamitani H, Nambu T, Yamane K, Yamanaka T, Sugimori-Shinozuka C, Tatami T, Inoue J, Kamei M, Morita S, Leung KP, Fukushima H. Identification of the genes involved in the biofilm-like structures on actinomyces oris K20, a clinical isolate from an apical lesion. J Endod 2012; 39:44-8. [PMID: 23228256 DOI: 10.1016/j.joen.2012.08.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2010] [Revised: 08/21/2012] [Accepted: 08/21/2012] [Indexed: 12/29/2022]
Abstract
INTRODUCTION Although the production of biofilm is thought to be crucial in the pathogenesis of abscess formations caused by oral resident microorganisms, the particular mechanisms are still unknown. The aim of this study was to identify gene(s) responsible for maintaining the cell surface-associated meshwork-like structures, which are found in some biofilm-producing bacteria, in a clinical isolate of Actinomyces oris K20. METHODS Random insertional mutagenesis by using transposon EZ-Tn5 was performed against the strain K20. Transposon insertion mutants were screened by scanning electron microscopy for the absence of cell surface-associated meshwork-like structures. The disrupted genes by the transposon insertion were determined by direct genome sequencing with the transposon-end primers. RESULTS Five mutants without the meshwork-like structures were identified from 175 mutants. Sequencing of flanking regions of transposon insertion revealed that 3 mutants had a gene encoded polysaccharide deacetylase, Spo0J containing ParB-like nuclease domain, and hypothetical protein, respectively. The other 2 mutants had an insertion in a noncoding region and an unidentified region, respectively. CONCLUSIONS Our findings indicated that these genes might be involved in the formation of meshwork-like structures on Actinomyces oris K20.
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Affiliation(s)
- Chiho Mashimo
- Department of Bacteriology, Osaka Dental University, Osaka, Japan.
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Bellows LE, Koestler BJ, Karaba SM, Waters CM, Lathem WW. Hfq-dependent, co-ordinate control of cyclic diguanylate synthesis and catabolism in the plague pathogen Yersinia pestis. Mol Microbiol 2012; 86:661-74. [PMID: 22924957 DOI: 10.1111/mmi.12011] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/20/2012] [Indexed: 01/14/2023]
Abstract
Yersinia pestis, the cause of the disease plague, forms biofilms to enhance flea-to-mammal transmission. Biofilm formation is dependent on exopolysaccharide synthesis and is controlled by the intracellular levels of the second messenger molecule cyclic diguanylate (c-di-GMP), but the mechanisms by which Y. pestis regulates c-di-GMP synthesis and turnover are not fully understood. Here we show that the small RNA chaperone Hfq contributes to the regulation of c-di-GMP levels and biofilm formation by modulating the abundance of both the c-di-GMP phosphodiesterase HmsP and the diguanylate cyclase HmsT. To do so, Hfq co-ordinately promotes hmsP mRNA accumulation while simultaneously decreasing the stability of the hmsT transcript. Hfq-dependent regulation of HmsP occurs at the transcriptional level while the regulation of HmsT is post-transcriptional and is localized to the 5' untranslated region/proximal coding sequence of the hmsT transcript. Decoupling HmsP from Hfq-based regulation is sufficient to overcome the effects of Δhfq on c-di-GMP and biofilm formation. We propose that Y. pestis utilizes Hfq to link c-di-GMP levels to environmental conditions and that the disregulation of c-di-GMP turnover in the absence of Hfq may contribute to the severe attenuation of Y. pestis lacking this RNA chaperone in animal models of plague.
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Affiliation(s)
- Lauren E Bellows
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
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24
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Little DJ, Poloczek J, Whitney JC, Robinson H, Nitz M, Howell PL. The structure- and metal-dependent activity of Escherichia coli PgaB provides insight into the partial de-N-acetylation of poly-β-1,6-N-acetyl-D-glucosamine. J Biol Chem 2012; 287:31126-37. [PMID: 22810235 DOI: 10.1074/jbc.m112.390005] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Exopolysaccharides are required for the development and integrity of biofilms produced by a wide variety of bacteria. In Escherichia coli, partial de-N-acetylation of the exopolysaccharide poly-β-1,6-N-acetyl-D-glucosamine (PNAG) by the periplasmic protein PgaB is required for polysaccharide intercellular adhesin-dependent biofilm formation. To understand the molecular basis for PNAG de-N-acetylation, the structure of PgaB in complex with Ni(2+) and Fe(3+) have been determined to 1.9 and 2.1 Å resolution, respectively, and its activity on β-1,6-GlcNAc oligomers has been characterized. The structure of PgaB reveals two (β/α)(x) barrel domains: a metal-binding de-N-acetylase that is a member of the family 4 carbohydrate esterases (CE4s) and a domain structurally similar to glycoside hydrolases. PgaB displays de-N-acetylase activity on β-1,6-GlcNAc oligomers but not on the β-1,4-(GlcNAc)(4) oligomer chitotetraose and is the first CE4 member to exhibit this substrate specificity. De-N-acetylation occurs in a length-dependent manor, and specificity is observed for the position of de-N-acetylation. A key aspartic acid involved in de-N-acetylation, normally seen in other CE4s, is missing in PgaB, suggesting that the activity of PgaB is attenuated to maintain the low levels of de-N-acetylation of PNAG observed in vivo. The metal dependence of PgaB is different from most CE4s, because PgaB shows increased rates of de-N-acetylation with Co(2+) and Ni(2+) under aerobic conditions, and Co(2+), Ni(2+) and Fe(2+) under anaerobic conditions, but decreased activity with Zn(2+). The work presented herein will guide inhibitor design to combat biofilm formation by E. coli and potentially a wide range of medically relevant bacteria producing polysaccharide intercellular adhesin-dependent biofilms.
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Affiliation(s)
- Dustin J Little
- Program in Molecular Structure & Function, Research Institute, The Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
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The Yersinia pestis Rcs phosphorelay inhibits biofilm formation by repressing transcription of the diguanylate cyclase gene hmsT. J Bacteriol 2012; 194:2020-6. [PMID: 22328676 DOI: 10.1128/jb.06243-11] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Yersinia pestis, which causes bubonic plague, forms biofilms in fleas, its insect vectors, as a means to enhance transmission. Biofilm development is positively regulated by hmsT, encoding a diguanylate cyclase that synthesizes the bacterial second messenger cyclic-di-GMP. Biofilm development is negatively regulated by the Rcs phosphorelay signal transduction system. In this study, we show that Rcs-negative regulation is accomplished by repressing transcription of hmsT.
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Yan Q, Wang N. High-throughput screening and analysis of genes of Xanthomonas citri subsp. citri involved in citrus canker symptom development. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2012; 25:69-84. [PMID: 21899385 DOI: 10.1094/mpmi-05-11-0121] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Citrus canker is caused by Xanthomonas citri subsp. citri and is one of the most devastating diseases on citrus plants. To investigate the virulence mechanism of this pathogen, a mutant library of strain 306 containing approximately 22,000 mutants was screened for virulence-deficient mutants in grapefruit (Citrus paradise). Eighty-two genes were identified that contribute to citrus canker symptom development caused by X. citri subsp. citri. Among the 82 identified genes, 23 genes were classified as essential genes, as mutation of these genes caused severe reduction of bacterial growth in M9 medium. The remaining 59 genes were classified as putative virulence-related genes that include 32 previously reported virulence-related genes and 27 novel genes. The 32 known virulence-related genes include genes that are involved in the type III secretion system (T3SS) and T3SS effectors, the quorum-sensing system, extracellular polysaccharide and lipopolysaccharide synthesis, and general metabolic pathways. The contribution to pathogenesis by nine genes (pthA4, trpG, trpC, purD, hrpM, peh-1, XAC1230, XAC1548, and XAC3049) was confirmed by complementation assays. We further validated the mutated genes and their phenotypes by analyzing the EZ-Tn5 insertion copy number using Southern blot analysis. In conclusion, we have significantly advanced our understanding of the putative genetic determinants of the virulence mechanism of X. citri subsp. citri by identifying 59 putative virulence-related genes, including 27 novel genes.
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Affiliation(s)
- Qing Yan
- Department of Microbiology and Cell Science, University of Florida, Lake Alfred, FL, USA
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27
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Bacterial Biofilm and Peculiarities of Its Formation in Plague Agent and in Other Pathogenic Yersinia. PROBLEMS OF PARTICULARLY DANGEROUS INFECTIONS 2011. [DOI: 10.21055/0370-1069-2011-4(110)-5-11] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Genome sequencing and analysis of Yersina pestis KIM D27, an avirulent strain exempt from select agent regulation. PLoS One 2011; 6:e19054. [PMID: 21559501 PMCID: PMC3084740 DOI: 10.1371/journal.pone.0019054] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Accepted: 03/23/2011] [Indexed: 01/01/2023] Open
Abstract
Yersinia pestis is the causative agent of the plague. Y. pestis KIM 10+ strain was passaged and selected for loss of the 102 kb pgm locus, resulting in an attenuated strain, KIM D27. In this study, whole genome sequencing was performed on KIM D27 in order to identify any additional differences. Initial assemblies of 454 data were highly fragmented, and various bioinformatic tools detected between 15 and 465 SNPs and INDELs when comparing both strains, the vast majority associated with A or T homopolymer sequences. Consequently, Illumina sequencing was performed to improve the quality of the assembly. Hybrid sequence assemblies were performed and a total of 56 validated SNP/INDELs and 5 repeat differences were identified in the D27 strain relative to published KIM 10+ sequence. However, further analysis showed that 55 of these SNP/INDELs and 3 repeats were errors in the KIM 10+ reference sequence. We conclude that both 454 and Illumina sequencing were required to obtain the most accurate and rapid sequence results for Y. pestis KIMD27. SNP and INDELS calls were most accurate when both Newbler and CLC Genomics Workbench were employed. For purposes of obtaining high quality genome sequence differences between strains, any identified differences should be verified in both the new and reference genomes.
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29
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Zhou D, Yang R. Formation and regulation of Yersinia biofilms. Protein Cell 2011; 2:173-9. [PMID: 21380640 DOI: 10.1007/s13238-011-1024-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2011] [Accepted: 02/18/2011] [Indexed: 12/31/2022] Open
Abstract
Flea-borne transmission is a recent evolutionary adaptation that distinguishes the deadly Yersinia pestis from its progenitor Y. Pseudotuberculosis, a mild pathogen transmitted via the food-borne route. Y. Pestis synthesizes biofilms in the flea gut, which is important for fleaborne transmission. Yersinia biofilms are bacterial colonies surrounded by extracellular matrix primarily containing a homopolymer of N-acetyl-D-glucosamine that are synthesized by a set of specific enzymes. Yersinia biofilm production is tightly regulated at both transcriptional and post-transcriptional levels. All the known structural genes responsible for biofilm production are harbored in both Y. Pseudotuberculosis and Y. Pestis, but Y. Pestis has evolved changes in the regulation of biofilm development, thereby acquiring efficient arthropod-borne transmission.
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Affiliation(s)
- Dongsheng Zhou
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China.
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30
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Bobrov AG, Kirillina O, Ryjenkov DA, Waters CM, Price PA, Fetherston JD, Mack D, Goldman WE, Gomelsky M, Perry RD. Systematic analysis of cyclic di-GMP signalling enzymes and their role in biofilm formation and virulence in Yersinia pestis. Mol Microbiol 2010; 79:533-51. [PMID: 21219468 DOI: 10.1111/j.1365-2958.2010.07470.x] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Cyclic di-GMP (c-di-GMP) is a signalling molecule that governs the transition between planktonic and biofilm states. Previously, we showed that the diguanylate cyclase HmsT and the putative c-di-GMP phosphodiesterase HmsP inversely regulate biofilm formation through control of HmsHFRS-dependent poly-β-1,6-N-acetylglucosamine synthesis. Here, we systematically examine the functionality of the genes encoding putative c-di-GMP metabolic enzymes in Yersinia pestis. We determine that, in addition to hmsT and hmsP, only the gene y3730 encodes a functional enzyme capable of synthesizing c-di-GMP. The seven remaining genes are pseudogenes or encode proteins that do not function catalytically or are not expressed. Furthermore, we show that HmsP has c-di-GMP-specific phosphodiesterase activity. We report that a mutant incapable of c-di-GMP synthesis is unaffected in virulence in plague mouse models. Conversely, an hmsP mutant, unable to degrade c-di-GMP, is defective in virulence by a subcutaneous route of infection due to poly-β-1,6-N-acetylglucosamine overproduction. This suggests that c-di-GMP signalling is not only dispensable but deleterious for Y. pestis virulence. Our results show that a key event in the evolution of Y. pestis from the ancestral Yersinia pseudotuberculosis was a significant reduction in the complexity of its c-di-GMP signalling network likely resulting from the different disease cycles of these human pathogens.
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Affiliation(s)
- Alexander G Bobrov
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky, Lexington, KY, USA.
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31
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Eroshenko GA, Vidyaeva NA, Kutyrev VV. Comparative analysis of biofilm formation by main and nonmain subspecies Yersinia pestis strains. ACTA ACUST UNITED AC 2010; 59:513-20. [PMID: 20618849 DOI: 10.1111/j.1574-695x.2010.00719.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The biofilm-forming phenotype of 14 isolates from four 'nonmain' subspecies of Yersinia pestis was compared with eight isolates from the more commonly studied 'main' or epidemic subspecies of Y. pestis in this study. The four nonmain subspecies are more geographically limited, and are associated with certain mammalian hosts and regions of the Caucasus and Central Asia, whereas the main subspecies spread worldwide during the historic plague pandemics. With the main subspecies pestis, pigmentation on Congo red medium (CR(+)) correlated with biofilm formation on both abiotic and biotic surfaces. Main subspecies pestis strains that do not produce pigmentation on Congo red medium (CR(-)) have a deletion that includes the hmsF and hmsS genes known to be required for biofilm formation. CR(-) strains of the nonmain subspecies, altaica and ulegeica, differed however from pestis and, while defective for biofilms on the two surfaces, both had intact hmsF and hmsS genes. The presence of rcsA was also investigated and results showed that it occurred with a 30-bp insertion in all forms of the subspecies. These findings suggest that biofilms are regulated differently in altaica and ulegeica than they are in pestis and also indicate that the rcsA pseudogene arose early in Y. pestis evolution, increasing the ability of the strain to form biofilm and thereby increasing its effective transmission.
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Affiliation(s)
- Galina A Eroshenko
- Russian Anti-Plague Research Institute Microbe, Universitetskaya, Saratov, Russian Federation.
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32
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Fetherston JD, Kirillina O, Bobrov AG, Paulley JT, Perry RD. The yersiniabactin transport system is critical for the pathogenesis of bubonic and pneumonic plague. Infect Immun 2010; 78:2045-52. [PMID: 20160020 PMCID: PMC2863531 DOI: 10.1128/iai.01236-09] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Revised: 11/30/2009] [Accepted: 02/04/2010] [Indexed: 01/18/2023] Open
Abstract
Iron acquisition from the host is an important step in the pathogenic process. While Yersinia pestis has multiple iron transporters, the yersiniabactin (Ybt) siderophore-dependent system plays a major role in iron acquisition in vitro and in vivo. In this study, we determined that the Ybt system is required for the use of iron bound by transferrin and lactoferrin and examined the importance of the Ybt system for virulence in mouse models of bubonic and pneumonic plague. Y. pestis mutants unable to either transport Ybt or synthesize the siderophore were both essentially avirulent via subcutaneous injection (bubonic plague model). Surprisingly, via intranasal instillation (pneumonic plague model), we saw a difference in the virulence of Ybt biosynthetic and transport mutants. Ybt biosynthetic mutants displayed an approximately 24-fold-higher 50% lethal dose (LD(50)) than transport mutants. In contrast, under iron-restricted conditions in vitro, a Ybt transport mutant had a more severe growth defect than the Ybt biosynthetic mutant. Finally, a Delta pgm mutant had a greater loss of virulence than the Ybt biosynthetic mutant, indicating that the 102-kb pgm locus encodes a virulence factor, in addition to Ybt, that plays a role in the pathogenesis of pneumonic plague.
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Affiliation(s)
- Jacqueline D. Fetherston
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky, Lexington, Kentucky 40536-0298
| | - Olga Kirillina
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky, Lexington, Kentucky 40536-0298
| | - Alexander G. Bobrov
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky, Lexington, Kentucky 40536-0298
| | - James T. Paulley
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky, Lexington, Kentucky 40536-0298
| | - Robert D. Perry
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky, Lexington, Kentucky 40536-0298
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Wortham BW, Oliveira MA, Fetherston JD, Perry RD. Polyamines are required for the expression of key Hms proteins important for Yersinia pestis biofilm formation. Environ Microbiol 2010; 12:2034-47. [PMID: 20406298 DOI: 10.1111/j.1462-2920.2010.02219.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
We previously showed that mutations in the genes encoding the two main biosynthetic enzymes responsible for polyamine production, arginine decarboxylase (SpeA) and ornithine decarboxylase (SpeC) cause a loss of biofilm formation in Yersinia pestis. In Y. pestis the development of a biofilm is dependent on 6 Hms (hemin storage) proteins (HmsH, F, R, S, T and P) grouped into 3 operons; hmsHFRS, hmsT and hmsP. In this article we show that polyamines are necessary to maintain the levels of key Hms proteins. In the absence of polyamines there is an approximately 93%, approximately 43% and approximately 90% reduction in protein levels of HmsR, HmsS and HmsT respectively. Overexpression of hmsR and hmsT from plasmids alone can restore biofilm formation to a SpeA(-)SpeC(-) mutant. Addition of exogenous putrescine also restores normal levels of HmsR, HmsS, HmsT and biofilm production. Analyses using transcriptional reporters and quantitative RT-PCR indicate that the initiation of transcription and mRNA stability are not reduced by polyamine deficiency. Instead, translational reporters indicate that polyamines function at least in part by modulating the translation of HmsR and HmsT. Although construction of a consensus Shine-Dalgarno sequence upstream of hmsT modestly reduced the stimulation of translation by putrescine, additional mechanisms likely contribute to the polyamine-dependent expression of HmsT. Finally, we have shown that polyamines play a role in bubonic plague.
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Affiliation(s)
- Brian W Wortham
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY 40536, USA
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Vetter SM, Eisen RJ, Schotthoefer AM, Montenieri JA, Holmes JL, Bobrov AG, Bearden SW, Perry RD, Gage KL. Biofilm formation is not required for early-phase transmission of Yersinia pestis. MICROBIOLOGY-SGM 2010; 156:2216-2225. [PMID: 20395271 PMCID: PMC3068684 DOI: 10.1099/mic.0.037952-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Early-phase transmission (EPT) is a recently described model of plague transmission that explains the rapid spread of disease from flea to mammal host during an epizootic. Unlike the traditional blockage-dependent model of plague transmission, EPT can occur when a flea takes its first blood meal after initially becoming infected by feeding on a bacteraemic host. Blockage of the flea gut results from biofilm formation in the proventriculus, mediated by the gene products found in the haemin storage (hms) locus of the Yersinia pestis chromosome. Although biofilms are required for blockage-dependent transmission, the role of biofilms in EPT has yet to be determined. An artificial feeding system was used to feed Xenopsylla cheopis and Oropsylla montana rat blood spiked with the parental Y. pestis strain KIM5(pCD1)+, two different biofilm-deficient mutants (ΔhmsT, ΔhmsR), or a biofilm-overproducer mutant (ΔhmsP). Infected fleas were then allowed to feed on naïve Swiss Webster mice for 1–4 days after infection, and the mice were monitored for signs of infection. We also determined the bacterial loads of each flea that fed upon naïve mice. Biofilm-defective mutants transmitted from X. cheopis and O. montana as efficiently as the parent strain, whereas the EPT efficiency of fleas fed the biofilm-overproducing strain was significantly less than that of fleas fed either the parent or a biofilm-deficient strain. Fleas infected with a biofilm-deficient strain harboured lower bacterial loads 4 days post-infection than fleas infected with the parent strain. Thus, defects in biofilm formation did not prevent flea-borne transmission of Y. pestis in our EPT model, although biofilm overproduction inhibited efficient EPT. Our results also indicate, however, that biofilms may play a role in infection persistence in the flea.
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Affiliation(s)
- Sara M Vetter
- Bacterial Diseases Branch, Division of Vector Borne Diseases, National Center for Enteric and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 3150 Rampart Rd, Fort Collins, CO 80521, USA
| | - Rebecca J Eisen
- Bacterial Diseases Branch, Division of Vector Borne Diseases, National Center for Enteric and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 3150 Rampart Rd, Fort Collins, CO 80521, USA
| | - Anna M Schotthoefer
- Bacterial Diseases Branch, Division of Vector Borne Diseases, National Center for Enteric and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 3150 Rampart Rd, Fort Collins, CO 80521, USA
| | - John A Montenieri
- Bacterial Diseases Branch, Division of Vector Borne Diseases, National Center for Enteric and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 3150 Rampart Rd, Fort Collins, CO 80521, USA
| | - Jennifer L Holmes
- Bacterial Diseases Branch, Division of Vector Borne Diseases, National Center for Enteric and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 3150 Rampart Rd, Fort Collins, CO 80521, USA
| | - Alexander G Bobrov
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky, MS415 Medical Center, Lexington, KY 40536, USA
| | - Scott W Bearden
- Bacterial Diseases Branch, Division of Vector Borne Diseases, National Center for Enteric and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 3150 Rampart Rd, Fort Collins, CO 80521, USA
| | - Robert D Perry
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky, MS415 Medical Center, Lexington, KY 40536, USA
| | - Kenneth L Gage
- Bacterial Diseases Branch, Division of Vector Borne Diseases, National Center for Enteric and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 3150 Rampart Rd, Fort Collins, CO 80521, USA
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Abu Khweek A, Fetherston JD, Perry RD. Analysis of HmsH and its role in plague biofilm formation. MICROBIOLOGY-SGM 2010; 156:1424-1438. [PMID: 20093287 DOI: 10.1099/mic.0.036640-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The Yersinia pestis Hms(+) phenotype is a manifestation of biofilm formation that causes adsorption of Congo red and haemin at 26 degrees C but not at 37 degrees C. This phenotype is required for blockage of the proventricular valve of the oriental rat flea and plays a role in transmission of bubonic plague from fleas to mammals. Genes responsible for this phenotype are located in three separate operons, hmsHFRS, hmsT and hmsP. HmsH and HmsF are outer membrane (OM) proteins, while the other four Hms proteins are located in the inner membrane. According to the Hidden Markov Method-based predictor, HmsH has a large N terminus in the periplasm, a beta-barrel structure with 16 beta-strands that traverse the OM, eight surface-exposed loops, and seven short turns connecting the beta-strands on the periplasmic side. Here, we demonstrate that HmsH is a heat-modifiable protein, a characteristic of other beta-barrel proteins, thereby supporting the bioinformatics analysis. Alanine scanning mutagenesis was used to identify conserved amino acids in the HmsH-like family that are critical for the function of HmsH in biofilm formation. Of 23 conserved amino acids mutated, four residues affected HmsH function and three likely caused protein instability. We used formaldehyde cross-linking to demonstrate that HmsH interacts with HmsF but not with HmsR, HmsS, HmsT or HmsP. Loss-of-function HmsH variants with single alanine substitutions retained their beta-structure and interaction with HmsF. Finally, using a polar hmsH : : mini-kan mutant, we demonstrated that biofilm development is not important for the pathogenesis of bubonic or pneumonic plague in mice.
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Affiliation(s)
- Arwa Abu Khweek
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky, 800 Rose St., Lexington, KY, USA
| | - Jacqueline D Fetherston
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky, 800 Rose St., Lexington, KY, USA
| | - Robert D Perry
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky, 800 Rose St., Lexington, KY, USA
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Becker S, Soares C, Porto LM. Computational analysis suggests that virulence of Chromobacterium violaceum might be linked to biofilm formation and poly-NAG biosynthesis. Genet Mol Biol 2009; 32:640-4. [PMID: 21637531 PMCID: PMC3036065 DOI: 10.1590/s1415-47572009000300031] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2008] [Accepted: 05/25/2009] [Indexed: 11/29/2022] Open
Abstract
Groups of genes that produce exopolysaccharide with a N-acetyl-D-glucosamine monomer are in the genome of several pathogenic bacteria. Chromobacterium violaceum, an opportunistic pathogen, has the operon hmsHFR-CV2940, whose proteins can synthesize such polysaccharide. In this work, multiple alignments among proteins from bacteria that synthesize such polysaccharide were used to verify the existence of amino acids that might be critical for pathogen activity. Three-dimensional models were generated for spatial visualization of these amino acid residues. The analysis carried out showed that the protein HmsR preserves the amino acids D135, D228, Q264 and R267, considered critical for the formation of biofilms and, furthermore, that these amino acids are close to each other. The protein HmsF of C. violaceum preserves the residues D86, D87, H156 and W115. It was also shown that these residues are also close to each other in their spatial arrangement. For the proteins HmsH and CV2940 there is evidence of conservation of the residues R104 and W94, respectively. Conservation and favorable spatial location of those critical amino acids that constitute the proteins of the operon indicates that they preserve the same enzymatic function in biofilm synthesis. This is an indicator that the operon hmsHFR-CV2940 is a possible target in C. violaceum pathogenicity.
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Affiliation(s)
- Sidnei Becker
- Laboratório de Tecnologias Integradas, Departamento de Engenharia Química e de Alimentos, Universidade Federal de Santa Catarina, Florianópolis, SC Brazil
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Sun YC, Koumoutsi A, Darby C. The response regulator PhoP negatively regulates Yersinia pseudotuberculosis and Yersinia pestis biofilms. FEMS Microbiol Lett 2008; 290:85-90. [PMID: 19025559 DOI: 10.1111/j.1574-6968.2008.01409.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
A few Yersinia pseudotuberculosis strains form biofilms on the head of the nematode Caenorhabditis elegans, but numerous others do not. We show that a widely used Y. pseudotuberculosis strain, YPIII, is biofilm positive because of a mutation in phoP, which encodes the response regulator of a two-component system. For two wild-type Y. pseudotuberculosis that do not make biofilms on C. elegans, deletion of phoP was sufficient to produce robust biofilms. In Yersinia pestis, a phoP mutant made more extensive biofilms in vitro than did the wild type. Expression of HmsT, a diguanylate cyclase that positively regulates biofilms, is diminished in Y. pseudotuberculosis strains with functional PhoP.
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Affiliation(s)
- Yi-Cheng Sun
- Department of Cell and Tissue Biology, Program in Microbial Pathogenesis, University of California, San Francisco, CA, USA
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Tarighi S, Wei Q, Cámara M, Williams P, Fletcher MP, Kajander T, Cornelis P. The PA4204 gene encodes a periplasmic gluconolactonase (PpgL) which is important for fitness of Pseudomonas aeruginosa. MICROBIOLOGY-SGM 2008; 154:2979-2990. [PMID: 18832304 DOI: 10.1099/mic.0.2008/018465-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In Pseudomonas aeruginosa, the PA4204 gene encodes a protein with a signal peptide and a COG2706 domain of the type present in 3-carboxy-cis,cis-muconate lactonizing enzymes. A molecular model based on the structure of the Escherichia coli YbhE phosphogluconate lactonizing enzyme shows that the enzyme has a beta-propeller ('doughnut') structure and a central active site comprising one histidine, one glutamic acid and two arginines. Inactivation of the P. aeruginosa PA4204 gene had profound phenotypic effects, resulting in slowly growing small colonies which frequently gave rise to larger colonies. The small colonies did not produce pyocyanin, produced reduced amounts of N-acylhomoserine lactones, and had extremely low levels of 2-alkyl-4-quinolones (AQs), while the larger colonies produced pyocyanin and higher amounts of AQs, including the pseudomonas quinolone signal (PQS), compared with the wild-type strain. Mutagenesis of His 182 in PA4204 resulted in the inability of this protein to restore pyocyanin production in the PA4204 isogenic mutant, suggesting that this enzyme may share an active site with other lactonizing enzymes. The protein with signal peptide was expressed as a His fusion in E. coli and purified. Two forms were observed, suggesting that the protein is translocated. The purified enzyme cleaved (S)-5-oxo-2-tetrahydrofurancarboxylic acid and d-glucono-delta-lactone, demonstrating lactonase activity. Decreased expression of the cytoplasmic phosphogluconolactonase gene (pgl) was observed in the small-colony mutant, and the mutant could not grow in the presence of mannitol or gluconate, suggesting functions in the detoxification of a gluconolactone and in sugar metabolism.
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Affiliation(s)
- Saeed Tarighi
- Laboratory of Microbial Interactions, Department of Molecular and Cellular Interactions, Flanders Institute of Biotechnology (VIB), Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Qing Wei
- Laboratory of Microbial Interactions, Department of Molecular and Cellular Interactions, Flanders Institute of Biotechnology (VIB), Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Miguel Cámara
- Institute of Infection, Immunity and Inflammation, Centre for Biomolecular Sciences, University Park, University of Nottingham, Nottingham NG7 2RD, UK
| | - Paul Williams
- Institute of Infection, Immunity and Inflammation, Centre for Biomolecular Sciences, University Park, University of Nottingham, Nottingham NG7 2RD, UK
| | - Matthew P Fletcher
- Institute of Infection, Immunity and Inflammation, Centre for Biomolecular Sciences, University Park, University of Nottingham, Nottingham NG7 2RD, UK
| | - Tommi Kajander
- Macromolecular X-ray Crystallography, Research Program in Structural Biology and Biophysics, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Pierre Cornelis
- Laboratory of Microbial Interactions, Department of Molecular and Cellular Interactions, Flanders Institute of Biotechnology (VIB), Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
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Experimental evidence for negative selection in the evolution of a Yersinia pestis pseudogene. Proc Natl Acad Sci U S A 2008; 105:8097-101. [PMID: 18523005 DOI: 10.1073/pnas.0803525105] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Yersinia pestis, the agent of bubonic plague, evolved from the enteric pathogen Yersinia pseudotuberculosis within the past 20,000 years. Because ancestor and descendant both exist, it is possible to infer steps in molecular evolution by direct experimental approaches. The Y. pestis life cycle includes establishment of a biofilm within its vector, the flea. Although Y. pseudotuberculosis makes biofilms in other environments, it fails to do so in the insect. We show that rcsA, a negative regulator of biofilms that is functional in Y. pseudotuberculosis, is a pseudogene in Y. pestis. Replacement of the pseudogene with the functional Y. pseudotuberculosis rcsA allele strongly represses biofilm formation and essentially abolishes flea biofilms. The conversion of rcsA to a pseudogene during Y. pestis evolution, therefore, was a case of negative selection rather than neutral genetic drift.
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The hmsHFRS operon of Xenorhabdus nematophila is required for biofilm attachment to Caenorhabditis elegans. Appl Environ Microbiol 2008; 74:4509-15. [PMID: 18515487 DOI: 10.1128/aem.00336-08] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The bacterium Xenorhabdus nematophila is an insect pathogen and an obligate symbiont of the nematode Steinernema carpocapsae. X. nematophila makes a biofilm that adheres to the head of the model nematode Caenorhabditis elegans, a capability X. nematophila shares with the biofilms made by Yersinia pestis and Yersinia pseudotuberculosis. As in Yersinia spp., the X. nematophila biofilm requires a 4-gene operon, hmsHFRS. Also like its Yersinia counterparts, the X. nematophila biofilm is bound by the lectin wheat germ agglutinin, suggesting that beta-linked N-acetyl-D-glucosamine or N-acetylneuraminic acid is a component of the extracellular matrix. C. elegans mutants with aberrant surfaces that do not permit Yersinia biofilm attachment also are resistant to X. nematophila biofilms. An X. nematophila hmsH mutant that failed to make biofilms on C. elegans had no detectable defect in symbiotic association with S. carpocapsae, nor was virulence reduced against the insect Manduca sexta.
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Itoh Y, Rice JD, Goller C, Pannuri A, Taylor J, Meisner J, Beveridge TJ, Preston JF, Romeo T. Roles of pgaABCD genes in synthesis, modification, and export of the Escherichia coli biofilm adhesin poly-beta-1,6-N-acetyl-D-glucosamine. J Bacteriol 2008; 190:3670-80. [PMID: 18359807 PMCID: PMC2394981 DOI: 10.1128/jb.01920-07] [Citation(s) in RCA: 208] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2007] [Accepted: 03/08/2008] [Indexed: 01/13/2023] Open
Abstract
The linear homopolymer poly-beta-1,6-N-acetyl-D-glucosamine (beta-1,6-GlcNAc; PGA) serves as an adhesin for the maintenance of biofilm structural stability in diverse eubacteria. Its function in Escherichia coli K-12 requires the gene products of the pgaABCD operon, all of which are necessary for biofilm formation. PgaC is an apparent glycosyltransferase that is required for PGA synthesis. Using a monoclonal antibody directed against E. coli PGA, we now demonstrate that PgaD is also needed for PGA formation. The deletion of genes for the predicted outer membrane proteins PgaA and PgaB did not prevent PGA synthesis but did block its export, as shown by the results of immunoelectron microscopy (IEM) and antibody adsorption assays. IEM also revealed a conditional localization of PGA at the cell poles, the initial attachment site for biofilm formation. PgaA contains a predicted beta-barrel porin and a superhelical domain containing tetratricopeptide repeats, which may mediate protein-protein interactions, implying that it forms the outer membrane secretin for PGA. PgaB contains predicted carbohydrate binding and polysaccharide N-deacetylase domains. The overexpression of pgaB increased the primary amine content (glucosamine) of PGA. Site-directed mutations targeting the N-deacetylase catalytic activity of PgaB blocked PGA export and biofilm formation, implying that N-deacetylation promotes PGA export through the PgaA porin. The results of previous studies indicated that N-deacetylation of beta-1,6-GlcNAc in Staphylococcus epidermidis by the PgaB homolog, IcaB, anchors it to the cell surface. The deletion of icaB resulted in release of beta-1,6-GlcNAc into the growth medium. Thus, covalent modification of beta-1,6-GlcNAc by N-deacetylation serves distinct biological functions in gram-negative and gram-positive species, dictated by cell envelope differences.
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Affiliation(s)
- Yoshikane Itoh
- Department of Microbiology and Immunology, Emory University School of Medicine, 3105 Rollins Research Center, 1510 Clifton Rd. N.E., Atlanta, GA 30322, USA
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Darby C. Uniquely insidious: Yersinia pestis biofilms. Trends Microbiol 2008; 16:158-64. [PMID: 18339547 DOI: 10.1016/j.tim.2008.01.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2007] [Revised: 01/16/2008] [Accepted: 01/23/2008] [Indexed: 11/30/2022]
Abstract
Bubonic plague, one of history's deadliest infections, is transmitted by fleas infected with Yersinia pestis. The bacteria can starve fleas by blocking their digestive tracts, which stimulates the insects to bite repeatedly and thereby infect new hosts. Direct examination of infected fleas, aided by in vitro studies and experiments with the nematode Caenorhabditis elegans, have established that Y. pestis forms a biofilm in the insect. The extracellular matrix of the biofilm seems to contain a homopolymer of N-acetyl-d-glucosamine, which is a constituent of many bacterial biofilms. A regulatory mechanism involved in Y. pestis biofilm formation, cyclic-di-GMP signaling, is also widespread in bacteria; yet only Y. pestis forms biofilms in fleas. Here, the historical background of bubonic plague is briefly described and recent studies investigating the mechanisms by which these unique and deadly biofilms are formed are discussed.
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Affiliation(s)
- Creg Darby
- Department of Cell and Tissue Biology, University of California, San Francisco, Box 0640/Room C-734, San Francisco, CA 94143-0640, USA.
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Bobrov AG, Kirillina O, Forman S, Mack D, Perry RD. Insights into Yersinia pestis biofilm development: topology and co-interaction of Hms inner membrane proteins involved in exopolysaccharide production. Environ Microbiol 2008; 10:1419-32. [DOI: 10.1111/j.1462-2920.2007.01554.x] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Staphylococcus epidermidis Biofilms: Functional Molecules, Relation to Virulence, and Vaccine Potential. GLYCOSCIENCE AND MICROBIAL ADHESION 2008; 288:157-82. [DOI: 10.1007/128_2008_19] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Hinnebusch BJ, Erickson DL. Yersinia pestis biofilm in the flea vector and its role in the transmission of plague. Curr Top Microbiol Immunol 2008; 322:229-48. [PMID: 18453279 DOI: 10.1007/978-3-540-75418-3_11] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Transmission by fleabite is a relatively recent evolutionary adaptation of Yersinia pestis, the bacterial agent of bubonic plague. To produce a transmissible infection, Y. pestis grows as an attached biofilm in the foregut of the flea vector. Biofilm formation both in the flea foregut and in vitro is dependent on an extracellular matrix (ECM) synthesized by the Yersinia hms gene products. The hms genes are similar to the pga and ica genes of Escherichia coli and Staphylococcus epidermidis, respectively, that act to synthesize a poly-beta-1,6-N-acetyl-d-glucosamine ECM required for biofilm formation. As with extracellular polysaccharide production in many other bacteria, synthesis of the Hms-dependent ECM is controlled by intracellular levels of cyclic-di-GMP. Yersinia pseudotuberculosis, the food- and water-borne enteric pathogen from which Y. pestis evolved recently, possesses identical hms genes and can form biofilm in vitro but not in the flea. The genetic changes in Y. pestis that resulted in adapting biofilm-forming capability to the flea gut environment, a critical step in the evolution of vector-borne transmission, have yet to be identified. During a flea bite, Y. pestis is regurgitated into the dermis in a unique biofilm phenotype, and this has implications for the initial interaction with the mammalian innate immune response.
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Affiliation(s)
- B J Hinnebusch
- Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, NIH, NIAID, Hamilton, MT 59840, USA.
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Forman S, Nagiec MJ, Abney J, Perry RD, Fetherston JD. Analysis of the aerobactin and ferric hydroxamate uptake systems of Yersinia pestis. MICROBIOLOGY-SGM 2007; 153:2332-2341. [PMID: 17600077 DOI: 10.1099/mic.0.2006/004275-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Yersinia pestis genomes contain genes homologous to the aerobactin receptor (iutA) and biosynthetic genes (iucABCD) as well as the ferric hydroxamate uptake system (fhuCDB) of Escherichia coli. However, iucA is disrupted by a frameshift mutation. An E. coli strain carrying the cloned Y. pestis aerobactin region was unable to produce aerobactin, but could use the siderophore as an iron source. Repair of the frameshift mutation in iucA did not allow aerobactin production in E. coli or Y. pestis. In contrast, a Y. pestis strain with a plasmid encoding the iucABCD-iutA genes from Shigella flexneri or pColV-K30 did produce and secrete the siderophore. In addition, Yersinia pseudotuberculosis PB1, which encodes the iucABCD-iutA locus without the Y. pestis-specific frameshift mutation, also failed to produce aerobactin. The Y. pestis fhuCDB operon, encoding an ABC transporter for a range of hydroxamate siderophores, was able to complement a strain of E. coli with a transposon insertion in fhuC, allowing utilization of aerobactin and ferrichrome. Y. pestis KIM6, a strain deficient in the production of the siderophore yersiniabactin, was able to use both the ferrichrome and the aerobactin siderophores as a source of iron. Mutations in iutA or the fhu operon abolished the ability of KIM6 to use aerobactin. Mutations in the fhu operon, but not in iutA, affected the ability of KIM6 to use ferrichrome. This demonstrates that Y. pestis uses both ferrichrome and aerobactin, but has lost the ability to synthesize aerobactin.
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Affiliation(s)
- Stanislav Forman
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky, Lexington, KY 40536-0298, USA
| | - Michal J Nagiec
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky, Lexington, KY 40536-0298, USA
| | - Jennifer Abney
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky, Lexington, KY 40536-0298, USA
| | - Robert D Perry
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky, Lexington, KY 40536-0298, USA
| | - Jacqueline D Fetherston
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky, Lexington, KY 40536-0298, USA
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