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Lewis JM, Jebeli L, Coulon PML, Lay CE, Scott NE. Glycoproteomic and proteomic analysis of Burkholderia cenocepacia reveals glycosylation events within FliF and MotB are dispensable for motility. Microbiol Spectr 2024; 12:e0034624. [PMID: 38709084 DOI: 10.1128/spectrum.00346-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2024] [Accepted: 04/16/2024] [Indexed: 05/07/2024] Open
Abstract
Across the Burkholderia genus O-linked protein glycosylation is highly conserved. While the inhibition of glycosylation has been shown to be detrimental for virulence in Burkholderia cepacia complex species, such as Burkholderia cenocepacia, little is known about how specific glycosylation sites impact protein functionality. Within this study, we sought to improve our understanding of the breadth, dynamics, and requirement for glycosylation across the B. cenocepacia O-glycoproteome. Assessing the B. cenocepacia glycoproteome across different culture media using complementary glycoproteomic approaches, we increase the known glycoproteome to 141 glycoproteins. Leveraging this repertoire of glycoproteins, we quantitively assessed the glycoproteome of B. cenocepacia using Data-Independent Acquisition (DIA) revealing the B. cenocepacia glycoproteome is largely stable across conditions with most glycoproteins constitutively expressed. Examination of how the absence of glycosylation impacts the glycoproteome reveals that the protein abundance of only five glycoproteins (BCAL1086, BCAL2974, BCAL0525, BCAM0505, and BCAL0127) are altered by the loss of glycosylation. Assessing ΔfliF (ΔBCAL0525), ΔmotB (ΔBCAL0127), and ΔBCAM0505 strains, we demonstrate the loss of FliF, and to a lesser extent MotB, mirror the proteomic effects observed in the absence of glycosylation in ΔpglL. While both MotB and FliF are essential for motility, we find loss of glycosylation sites in MotB or FliF does not impact motility supporting these sites are dispensable for function. Combined this work broadens our understanding of the B. cenocepacia glycoproteome supporting that the loss of glycoproteins in the absence of glycosylation is not an indicator of the requirement for glycosylation for protein function. IMPORTANCE Burkholderia cenocepacia is an opportunistic pathogen of concern within the Cystic Fibrosis community. Despite a greater appreciation of the unique physiology of B. cenocepacia gained over the last 20 years a complete understanding of the proteome and especially the O-glycoproteome, is lacking. In this study, we utilize systems biology approaches to expand the known B. cenocepacia glycoproteome as well as track the dynamics of glycoproteins across growth phases, culturing media and in response to the loss of glycosylation. We show that the glycoproteome of B. cenocepacia is largely stable across conditions and that the loss of glycosylation only impacts five glycoproteins including the motility associated proteins FliF and MotB. Examination of MotB and FliF shows, while these proteins are essential for motility, glycosylation is dispensable. Combined this work supports that B. cenocepacia glycosylation can be dispensable for protein function and may influence protein properties beyond stability.
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Affiliation(s)
- Jessica M Lewis
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Leila Jebeli
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Pauline M L Coulon
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Catrina E Lay
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Nichollas E Scott
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
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Lewis J, Scott NE. CRISPRi-Mediated Silencing of Burkholderia O-Linked Glycosylation Systems Enables the Depletion of Glycosylation Yet Results in Modest Proteome Impacts. J Proteome Res 2023; 22:1762-1778. [PMID: 36995114 PMCID: PMC10243306 DOI: 10.1021/acs.jproteome.2c00790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Indexed: 03/31/2023]
Abstract
The process of O-linked protein glycosylation is highly conserved across the Burkholderia genus and mediated by the oligosaccharyltransferase PglL. While our understanding of Burkholderia glycoproteomes has increased in recent years, little is known about how Burkholderia species respond to modulations in glycosylation. Utilizing CRISPR interference (CRISPRi), we explored the impact of silencing of O-linked glycosylation across four species of Burkholderia; Burkholderia cenocepacia K56-2, Burkholderia diffusa MSMB375, Burkholderia multivorans ATCC17616, and Burkholderia thailandensis E264. Proteomic and glycoproteomic analyses revealed that while CRISPRi enabled inducible silencing of PglL, this did not abolish glycosylation, nor recapitulate phenotypes such as proteome changes or alterations in motility that are associated with glycosylation null strains, despite inhibition of glycosylation by nearly 90%. Importantly, this work also demonstrated that CRISPRi induction with high levels of rhamnose leads to extensive impacts on the Burkholderia proteomes, which without appropriate controls mask the impacts specifically driven by CRISPRi guides. Combined, this work revealed that while CRISPRi allows the modulation of O-linked glycosylation with reductions up to 90% at a phenotypic and proteome levels, Burkholderia appears to demonstrate a robust tolerance to fluctuations in glycosylation capacity.
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Affiliation(s)
- Jessica
M. Lewis
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute
for Infection and Immunity, Melbourne 3000, Australia
| | - Nichollas E. Scott
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute
for Infection and Immunity, Melbourne 3000, Australia
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Aiyer A, Manos J. The Use of Artificial Sputum Media to Enhance Investigation and Subsequent Treatment of Cystic Fibrosis Bacterial Infections. Microorganisms 2022; 10:microorganisms10071269. [PMID: 35888988 PMCID: PMC9318996 DOI: 10.3390/microorganisms10071269] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 06/16/2022] [Accepted: 06/17/2022] [Indexed: 12/04/2022] Open
Abstract
In cystic fibrosis (CF), mutations in the CF transmembrane conductance regulator protein reduce ionic exchange in the lung, resulting in thicker mucus, which impairs mucociliary function, airway inflammation and infection. The mucosal and nutritional environment of the CF lung is inadequately mimicked by commercially available growth media, as it lacks key components involved in microbial pathogenesis. Defining the nutritional composition of CF sputum has been a long-term goal of in vitro research into CF infections to better elucidate bacterial growth and infection pathways. This narrative review highlights the development of artificial sputum medium, from a viable in vitro method for understanding bacterial mechanisms utilised in CF lung, to uses in the development of antimicrobial treatment regimens and examination of interactions at the epithelial cell surface and interior by the addition of host cell layers. The authors collated publications based on a PubMed search using the key words: “artificial sputum media” and “cystic fibrosis”. The earliest iteration of artificial sputum media were developed in 1997. Formulations since then have been based either on published data or chemically derived from extracted sputum. Formulations contain combinations of mucin, extracellular DNA, iron, amino acids, and lipids. A valuable advantage of artificial sputum media is the ability to standardise media composition according to experimental requirements.
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Keefe BF, Bermudez LE. Environment in the lung of cystic fibrosis patients stimulates the expression of biofilm phenotype in Mycobacterium abscessus. J Med Microbiol 2022; 71. [PMID: 35014948 DOI: 10.1099/jmm.0.001467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Introduction. Pulmonary infections caused by organisms of the Mycobacterium abscessus complex are increasingly prevalent in populations at risk, such as patients with cystic fibrosis, bronchiectasis and emphysema.Hypothesis. M. abscessus infection of the lung is not observed in immunocompetent individuals, which raises the possibility that the compromised lung environment is a suitable niche for the pathogen to thrive in due to the overproduction of mucus and high amounts of host cell lysis.Aim. Evaluate the ability of M. abscessus to form biofilm and grow utilizing in vitro conditions as seen in immunocompromised lungs of patients.Methodology. We compared biofilm formation and protein composition in the presence and absence of synthetic cystic fibrosis medium (SCFM) and evaluated the bacterial growth when exposed to human DNA.Results. M. abscessus is capable of forming biofilm in SCFM. By eliminating single components found in the medium, it became clear that magnesium works as a signal for the biofilm formation, and chelation of the divalent cations resulted in the suppression of biofilm formation. Investigation of the specific proteins expressed in the presence of SCFM and in the presence of SCFM lacking magnesium revealed many different proteins between the conditions. M. abscessus also exhibited growth in SCFM and in the presence of host cell DNA, although the mechanism of DNA utilization remains unclear.Conclusions. In vitro conditions mimicking the airways of patients with cystic fibrosis appear to facilitate M. abscessus establishment of infection, and elimination of magnesium from the environment may affect the ability of the pathogen to establish infection.
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Affiliation(s)
- Bailey F Keefe
- Department of Biomedical Sciences, College of Veterinary Medicine, Corvallis, OR, USA
| | - Luiz E Bermudez
- Department of Biomedical Sciences, College of Veterinary Medicine, Corvallis, OR, USA.,Department of Microbiology, College of Sciences Oregon State University, Corvallis, OR, USA
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Fule L, Halifa R, Fontana C, Sismeiro O, Legendre R, Varet H, Coppée JY, Murray GL, Adler B, Hendrixson DR, Buschiazzo A, Guo S, Liu J, Picardeau M. Role of the major determinant of polar flagellation FlhG in the endoflagella-containing spirochete Leptospira. Mol Microbiol 2021; 116:1392-1406. [PMID: 34657338 DOI: 10.1111/mmi.14831] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 10/06/2021] [Accepted: 10/13/2021] [Indexed: 01/31/2023]
Abstract
Spirochetes can be distinguished from other bacteria by their spiral-shaped morphology and subpolar periplasmic flagella. This study focused on FlhF and FlhG, which control the spatial and numerical regulation of flagella in many exoflagellated bacteria, in the spirochete Leptospira. In contrast to flhF which seems to be essential in Leptospira, we demonstrated that flhG- mutants in both the saprophyte L. biflexa and the pathogen L. interrogans were less motile than the wild-type strains in gel-like environments but not hyperflagellated as reported previously in other bacteria. Cryo-electron tomography revealed that the distance between the flagellar basal body and the tip of the cell decreased significantly in the flhG- mutant in comparison to wild-type and complemented strains. Additionally, comparative transcriptome analyses of L. biflexa flhG- and wild-type strains showed that FlhG acts as a negative regulator of transcription of some flagellar genes. We found that the L. interrogans flhG- mutant was attenuated for virulence in the hamster model. Cross-species complementation also showed that flhG is not interchangeable between species. Our results indicate that FlhF and FlhG in Leptospira contribute to governing cell motility but our data support the hypothesis that FlhF and FlhG function differently in each bacterial species, including among spirochetes.
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Affiliation(s)
- Lenka Fule
- Institut Pasteur, Biology of Spirochetes Unit, Paris, France
- Pasteur International Unit, Integrative Microbiology of Zoonotic Agents, Institut Pasteur de Montevideo, Montevideo, Uruguay/Institut Pasteur, Paris, France
- Université de Paris, Paris, France
| | - Ruben Halifa
- Institut Pasteur, Biology of Spirochetes Unit, Paris, France
| | - Celia Fontana
- Boehringer Ingelheim Santé Animale, Saint Priest, France
| | - Odile Sismeiro
- Transcriptome and Epigenome Platform, Biomics, Center for Technological Resources and Research (C2RT), Institut Pasteur, Paris, France
| | - Rachel Legendre
- Transcriptome and Epigenome Platform, Biomics, Center for Technological Resources and Research (C2RT), Institut Pasteur, Paris, France
- Bioinformatics and Biostatistics Hub, Department of Computational Biology, Institut Pasteur, Paris, France
| | - Hugo Varet
- Transcriptome and Epigenome Platform, Biomics, Center for Technological Resources and Research (C2RT), Institut Pasteur, Paris, France
- Bioinformatics and Biostatistics Hub, Department of Computational Biology, Institut Pasteur, Paris, France
| | - Jean-Yves Coppée
- Transcriptome and Epigenome Platform, Biomics, Center for Technological Resources and Research (C2RT), Institut Pasteur, Paris, France
| | - Gerald L Murray
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Ben Adler
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - David R Hendrixson
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Alejandro Buschiazzo
- Pasteur International Unit, Integrative Microbiology of Zoonotic Agents, Institut Pasteur de Montevideo, Montevideo, Uruguay/Institut Pasteur, Paris, France
- Laboratory of Molecular and Structural Microbiology, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | - Shuaiqi Guo
- Microbial Sciences Institute & Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
| | - Jun Liu
- Microbial Sciences Institute & Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
| | - Mathieu Picardeau
- Institut Pasteur, Biology of Spirochetes Unit, Paris, France
- Pasteur International Unit, Integrative Microbiology of Zoonotic Agents, Institut Pasteur de Montevideo, Montevideo, Uruguay/Institut Pasteur, Paris, France
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Abstract
Bacteria in the Burkholderia cepacia complex (BCC) are significant pathogens for people with cystic fibrosis (CF) and are often extensively antibiotic resistant. Here, we assess the impacts of clinically observed mutations in fixL, which encodes the sensor histidine kinase FixL. FixL along with FixJ compose a two-component system that regulates multiple phenotypes. Mutations in fixL across two species, B. dolosa and B. multivorans, have shown evidence of positive selection during chronic lung infection in CF. Herein, we find that BCC carrying the conserved, ancestral fixL sequence have lower survival in macrophages and in murine pneumonia models than mutants carrying evolved fixL sequences associated with clinical decline in CF patients. In vitro phosphotransfer experiments found that one evolved FixL protein, W439S, has a reduced ability to autophosphorylate and phosphorylate FixJ, while LacZ reporter experiments demonstrate that B. dolosa carrying evolved fixL alleles has reduced fix pathway activity. Interestingly, B. dolosa carrying evolved fixL alleles was less fit in a soil assay than those strains carrying the ancestral allele, demonstrating that increased survival of these variants in macrophages and the murine lung comes at a potential expense in their environmental reservoir. Thus, modulation of the two-component system encoded by fixLJ by point mutations is one mechanism that allows BCC to adapt to the host infection environment.
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Revealing the Metabolic Alterations during Biofilm Development of Burkholderia cenocepacia Based on Genome-Scale Metabolic Modeling. Metabolites 2021; 11:metabo11040221. [PMID: 33916474 PMCID: PMC8067366 DOI: 10.3390/metabo11040221] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 03/26/2021] [Accepted: 04/02/2021] [Indexed: 12/16/2022] Open
Abstract
Burkholderia cenocepacia is among the important pathogens isolated from cystic fibrosis (CF) patients. It has attracted considerable attention because of its capacity to evade host immune defenses during chronic infection. Advances in systems biology methodologies have led to the emergence of methods that integrate experimental transcriptomics data and genome-scale metabolic models (GEMs). Here, we integrated transcriptomics data of bacterial cells grown on exponential and biofilm conditions into a manually curated GEM of B. cenocepacia. We observed substantial differences in pathway response to different growth conditions and alternative pathway susceptibility to extracellular nutrient availability. For instance, we found that blockage of the reactions was vital through the lipid biosynthesis pathways in the exponential phase and the absence of microenvironmental lysine and tryptophan are essential for survival. During biofilm development, bacteria mostly had conserved lipid metabolism but altered pathway activities associated with several amino acids and pentose phosphate pathways. Furthermore, conversion of serine to pyruvate and 2,5-dioxopentanoate synthesis are also identified as potential targets for metabolic remodeling during biofilm development. Altogether, our integrative systems biology analysis revealed the interactions between the bacteria and its microenvironment and enabled the discovery of antimicrobial targets for biofilm-related diseases.
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Scoffone VC, Barbieri G, Buroni S, Scarselli M, Pizza M, Rappuoli R, Riccardi G. Vaccines to Overcome Antibiotic Resistance: The Challenge of Burkholderia cenocepacia. Trends Microbiol 2020; 28:315-326. [DOI: 10.1016/j.tim.2019.12.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 12/03/2019] [Accepted: 12/09/2019] [Indexed: 12/26/2022]
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9
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Hogan AM, Rahman ASMZ, Lightly TJ, Cardona ST. A Broad-Host-Range CRISPRi Toolkit for Silencing Gene Expression in Burkholderia. ACS Synth Biol 2019; 8:2372-2384. [PMID: 31491085 DOI: 10.1021/acssynbio.9b00232] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Genetic tools are critical to dissecting the mechanisms governing cellular processes, from fundamental physiology to pathogenesis. Members of the genus Burkholderia have potential for biotechnological applications but can also cause disease in humans with a debilitated immune system. The lack of suitable genetic tools to edit Burkholderia GC-rich genomes has hampered the exploration of useful capacities and the understanding of pathogenic features. To address this, we have developed CRISPR interference (CRISPRi) technology for gene silencing in Burkholderia, testing it in B. cenocepacia, B. multivorans, and B. thailandensis. Tunable expression was provided by placing a codon-optimized dcas9 from Streptococcus pyogenes under control of a rhamnose-inducible promoter. As a proof of concept, the paaABCDE operon controlling genes necessary for phenylacetic acid degradation was targeted by plasmid-borne gRNAs, resulting in near complete inhibition of growth on phenylacetic acid as the sole carbon source. This was supported by reductions in paaA mRNA expression. The utility of CRISPRi to probe other functions at the single cell level was demonstrated by knocking down phbC and fliF, which dramatically reduces polyhydroxybutyrate granule accumulation and motility, respectively. As a hallmark of the mini-CTX system is the broad host-range of integration, we putatively identified 67 genera of Proteobacteria that might be amenable to modification with our CRISPRi toolkit. Our CRISPRi toolkit provides a simple and rapid way to silence gene expression to produce an observable phenotype. Linking genes to functions with CRISPRi will facilitate genome editing with the goal of enhancing biotechnological capabilities while reducing Burkholderia's pathogenic arsenal.
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Affiliation(s)
- Andrew M Hogan
- Department of Microbiology , University of Manitoba , Winnipeg , Manitoba R3T 2N2 , Canada
| | - A S M Zisanur Rahman
- Department of Microbiology , University of Manitoba , Winnipeg , Manitoba R3T 2N2 , Canada
| | - Tasia J Lightly
- Department of Microbiology , University of Manitoba , Winnipeg , Manitoba R3T 2N2 , Canada
| | - Silvia T Cardona
- Department of Microbiology , University of Manitoba , Winnipeg , Manitoba R3T 2N2 , Canada
- Department of Medical Microbiology & Infectious Diseases , University of Manitoba , Winnipeg , Manitoba R3T 2N2 , Canada
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Stenotrophomonas maltophilia Differential Gene Expression in Synthetic Cystic Fibrosis Sputum Reveals Shared and Cystic Fibrosis Strain-Specific Responses to the Sputum Environment. J Bacteriol 2019; 201:JB.00074-19. [PMID: 31109991 DOI: 10.1128/jb.00074-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 05/14/2019] [Indexed: 12/19/2022] Open
Abstract
Stenotrophomonas maltophilia is a Gram-negative opportunistic pathogen that can infect the lungs of people with cystic fibrosis (CF). The highly viscous mucus in the CF lung, expectorated as sputum, serves as the primary nutrient source for microbes colonizing this site and induces virulence-associated phenotypes and gene expression in several CF pathogens. Here, we characterized the transcriptional responses of three S. maltophilia strains during exposure to synthetic CF sputum medium (SCFM2) to gain insight into how this organism interacts with the host in the CF lung. These efforts led to the identification of 881 transcripts differentially expressed by all three strains, many of which reflect the metabolic pathways used by S. maltophilia in sputum, as well as altered stress responses. The latter correlated with increased resistance to peroxide exposure after pregrowth in SCFM2 for two of the strains. We also compared the SCFM2 transcriptomes of two S. maltophilia CF isolates to that of the acute infection strain, S. maltophilia K279a, allowing us to identify CF isolate-specific signatures in differential gene expression. The expression of genes from the accessory genomes was also differentially altered in response to SCFM2. Finally, a number of biofilm-associated genes were differentially induced in SCFM2, particularly in K279a, which corresponded to increased aggregation and biofilm formation in this strain relative to both CF strains. Collectively, this work details the response of S. maltophilia to an environment that mimics important aspects of the CF lung, identifying potential survival strategies and metabolic pathways used by S. maltophilia during infections.IMPORTANCE Stenotrophomonas maltophilia is an important infecting bacterium in the airways of people with cystic fibrosis (CF). However, compared to the other CF pathogens, S. maltophilia has been relatively understudied. The significance of our research is to provide insight into the global transcriptomic changes of S. maltophilia in response to a medium that was designed to mimic important aspects of the CF lung. This study elucidates the overall metabolic changes that occur when S. maltophilia encounters the CF lung and generates a road map of candidate genes to test using in vitro and in vivo models of CF.
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Kumar B, Sorensen JL, Cardona ST. A c-di-GMP-Modulating Protein Regulates Swimming Motility of Burkholderia cenocepacia in Response to Arginine and Glutamate. Front Cell Infect Microbiol 2018. [PMID: 29541628 PMCID: PMC5835511 DOI: 10.3389/fcimb.2018.00056] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Burkholderia cenocepacia is an opportunistic bacterium that can thrive in different environments, including the amino acid-rich mucus of the cystic fibrosis (CF) lung. B. cenocepacia responds to the nutritional conditions that mimic the CF sputum by increasing flagellin expression and swimming motility. Individual amino acids also induce swimming but not flagellin expression. Here, we show that modulation of the second messenger cyclic dimeric guanosine monophosphate (c-di-GMP) levels by the PAS-containing c-di-GMP phosphodiesterase, BCAL1069 (CdpA), regulates the swimming motility of B. cenocepacia K56-2 in response to CF sputum nutritional conditions. Heterologous expression of WspR, a diguanylate cyclase, in B. cenocepacia K56-2 caused an increase in c-di-GMP levels and reduced swimming motility but did not affect flagellin expression or flagellar biosynthesis. After insertional mutagenesis of 12 putative genes encoding c-di-GMP metabolizing enzymes, one mutant of the locus BCAL1069 (cdpA), exhibited decreased swimming motility independent of flagellin expression in CF sputum nutritional conditions and an increase in intracellular c-di-GMP levels. The reduced swimming motility phenotype of the BCAL1069 mutant was observed in the presence of arginine and glutamate, but not of histidine, phenylalanine, or proline. The B. cenocepacia CdpA was also found to be involved in regulation of protease activity but not in biofilm formation. Altogether, these results highlight a role of B. cenocepacia BCAL1069 (CdpA) in sensing the nutritional conditions of the CF sputum and eliciting a pathogenic response that includes swimming motility toward amino acids and an increase in protease activity.
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Affiliation(s)
- Brijesh Kumar
- Department of Microbiology, Faculty of Science, University of Manitoba, Winnipeg, MB, Canada
| | - John L Sorensen
- Department of Chemistry, Faculty of Science, University of Manitoba, Winnipeg, MB, Canada
| | - Silvia T Cardona
- Department of Microbiology, Faculty of Science, University of Manitoba, Winnipeg, MB, Canada.,Department of Medical Microbiology & Infectious Diseases, Max Rady College of Medicine, University of Manitoba, Winnipeg, MB, Canada
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