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Sun Z, Heacock-Kang Y, McMillan IA, Cabanas D, Zarzycki-Siek J, Hoang TT. A virulence activator of a surface attachment protein in Burkholderia pseudomallei acts as a global regulator of other membrane-associated virulence factors. Front Microbiol 2023; 13:1063287. [PMID: 36726566 PMCID: PMC9884982 DOI: 10.3389/fmicb.2022.1063287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 12/30/2022] [Indexed: 01/19/2023] Open
Abstract
Burkholderia pseudomallei (Bp), causing a highly fatal disease called melioidosis, is a facultative intracellular pathogen that attaches and invades a variety of cell types. We previously identified BP1026B_I0091 as a surface attachment protein (Sap1) and an essential virulence factor, contributing to Bp pathogenesis in vitro and in vivo. The expression of sap1 is regulated at different stages of Bp intracellular lifecycle by unidentified regulator(s). Here, we identified SapR (BP1026B_II1046) as a transcriptional regulator that activates sap1, using a high-throughput transposon mutagenesis screen in combination with Tn-Seq. Consistent with phenotypes of the Δsap1 mutant, the ΔsapR activator mutant exhibited a significant reduction in Bp attachment to the host cell, leading to subsequent decreased intracellular replication. RNA-Seq analysis further revealed that SapR regulates sap1. The regulation of sap1 by SapR was confirmed quantitatively by qRT-PCR, which also validated the RNA-Seq data. SapR globally regulates genes associated with the bacterial membrane in response to diverse environments, and some of the genes regulated by SapR are virulence factors that are required for Bp intracellular infection (e.g., type III and type VI secretion systems). This study has identified the complex SapR regulatory network and its importance as an activator of an essential Sap1 attachment factor.
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Affiliation(s)
- Zhenxin Sun
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, United States
| | - Yun Heacock-Kang
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, United States
| | - Ian A McMillan
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, United States
| | - Darlene Cabanas
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, United States
| | - Jan Zarzycki-Siek
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, United States
| | - Tung T Hoang
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, United States
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McMillan IA, Norris MH, Zarzycki-Siek J, Heacock-Kang Y, Sun Z, Borlee BR, Hoang TT. Identification of a PadR-type regulator essential for intracellular pathogenesis of Burkholderia pseudomallei. Sci Rep 2021; 11:10405. [PMID: 34001967 PMCID: PMC8128862 DOI: 10.1038/s41598-021-89852-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 04/28/2021] [Indexed: 11/14/2022] Open
Abstract
Burkholderia pseudomallei (Bp) is the causative agent of melioidosis, a disease endemic to the tropics. Melioidosis manifests in various ways ranging from acute skin lesions to pneumonia and, in rare cases, infection of the central nervous system. Bp is a facultative intracellular pathogen and it can infect various cell types. The Bp intracellular lifecycle has been partially elucidated and is highly complex. Herein, we have identified a transcriptional regulator, BP1026B_II1198, that is differentially expressed as Bp transits through host cells. A deletion mutant of BP1026B_II1198 was attenuated in RAW264.7 cell and BALB/c mouse infection. To further characterize the function of this transcriptional regulator, we endeavored to determine the regulon of BP1026B_II1198. RNA-seq analysis showed the global picture of genes regulated while ChIP-seq analysis identified two specific BP1026B_II1198 binding regions on chromosome II. We investigated the transposon mutants of these genes controlled by BP1026B_II1198 and confirmed that these genes contribute to pathogenesis in RAW264.7 murine macrophage cells. Taken together, the data presented here shed light on the regulon of BP1026B_II1198 and its role during intracellular infection and highlights an integral portion of the highly complex regulation network of Bp during host infection.
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Affiliation(s)
- Ian A McMillan
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, Hawai'i, USA
| | - Michael H Norris
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, Hawai'i, USA
- Department of Geography and Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Jan Zarzycki-Siek
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, Hawai'i, USA
| | - Yun Heacock-Kang
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, Hawai'i, USA
| | - Zhenxin Sun
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, Hawai'i, USA
| | - Bradley R Borlee
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Tung T Hoang
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, Hawai'i, USA.
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Heacock-Kang Y, McMillan IA, Norris MH, Sun Z, Zarzycki-Siek J, Bluhm AP, Cabanas D, Norton RE, Ketheesan N, Miller JF, Schweizer HP, Hoang TT. The Burkholderia pseudomallei intracellular 'TRANSITome'. Nat Commun 2021; 12:1907. [PMID: 33772012 PMCID: PMC7998038 DOI: 10.1038/s41467-021-22169-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 02/26/2021] [Indexed: 01/01/2023] Open
Abstract
Prokaryotic cell transcriptomics has been limited to mixed or sub-population dynamics and individual cells within heterogeneous populations, which has hampered further understanding of spatiotemporal and stage-specific processes of prokaryotic cells within complex environments. Here we develop a 'TRANSITomic' approach to profile transcriptomes of single Burkholderia pseudomallei cells as they transit through host cell infection at defined stages, yielding pathophysiological insights. We find that B. pseudomallei transits through host cells during infection in three observable stages: vacuole entry; cytoplasmic escape and replication; and membrane protrusion, promoting cell-to-cell spread. The B. pseudomallei 'TRANSITome' reveals dynamic gene-expression flux during transit in host cells and identifies genes that are required for pathogenesis. We find several hypothetical proteins and assign them to virulence mechanisms, including attachment, cytoskeletal modulation, and autophagy evasion. The B. pseudomallei 'TRANSITome' provides prokaryotic single-cell transcriptomics information enabling high-resolution understanding of host-pathogen interactions.
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Affiliation(s)
- Yun Heacock-Kang
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA
| | - Ian A McMillan
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA
| | - Michael H Norris
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA
- Department of Geography and Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Zhenxin Sun
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA
| | - Jan Zarzycki-Siek
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA
| | - Andrew P Bluhm
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA
- Department of Geography and Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Darlene Cabanas
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA
| | - Robert E Norton
- Townsville Hospital, Townsville, QLD, Australia
- Faculty of Medicine, University of Queensland, Brisbane, Australia
| | - Natkunam Ketheesan
- Science and Technology, University of New England, New South Wales, Australia
| | - Jeff F Miller
- Department of Microbiology, Immunology, and Molecular Genetics, and the California NanoSystems Institute, University of California, Los Angeles, CA, USA
| | - Herbert P Schweizer
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ, USA
| | - Tung T Hoang
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA.
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Heacock-Kang Y, McMillan IA, Zarzycki-Siek J, Sun Z, Bluhm AP, Cabanas D, Hoang TT. The heritable natural competency trait of Burkholderia pseudomallei in other Burkholderia species through comE and crp. Sci Rep 2018; 8:12422. [PMID: 30127446 PMCID: PMC6102250 DOI: 10.1038/s41598-018-30853-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 08/02/2018] [Indexed: 11/17/2022] Open
Abstract
Natural competency requires uptake of exogenous DNA from the environment and the integration of that DNA into recipient bacteria can be used for DNA-repair or genetic diversification. The Burkholderia genus is unique in that only some of the species and strains are naturally competent. We identified and characterized two genes, comE and crp, from naturally competent B. pseudomallei 1026b that play a role in DNA uptake and catabolism. Single-copies of rhamnose-inducible comE and crp genes were integrated into a Tn7 attachment-site in non-naturally competent Burkholderia including pathogens B. pseudomallei K96243, B. cenocepacia K56-2, and B. mallei ATCC23344. Strains expressing comE or crp were assayed for their ability to uptake and catabolize DNA. ComE and Crp allowed non-naturally competent Burkholderia species to catabolize DNA, uptake exogenous gfp DNA and express GFP. Furthermore, we used synthetic comE and crp to expand the utility of the λ-red recombineering system for genetic manipulation of non-competent Burkholderia species. A newly constructed vector, pKaKa4, was used to mutate the aspartate semialdehyde dehydrogenase (asd) gene in four B. mallei strains, leading to the complete attenuation of these tier-1 select-agents. These strains have been excluded from select-agent regulations and will be of great interest to the field.
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Affiliation(s)
- Yun Heacock-Kang
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, USA
| | - Ian A McMillan
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, USA
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, Hawaii, USA
| | - Jan Zarzycki-Siek
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, USA
| | - Zhenxin Sun
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, USA
| | - Andrew P Bluhm
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, USA
| | - Darlene Cabanas
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, USA
| | - Tung T Hoang
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, USA.
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, Hawaii, USA.
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Norris MH, Heacock-Kang Y, Zarzycki-Siek J, Bluhm AP, McMillan IA, Schweizer HP, Hoang TT. Burkholderia pseudomallei natural competency and DNA catabolism: Identification and characterization of relevant genes from a constructed fosmid library. PLoS One 2017; 12:e0189018. [PMID: 29253888 PMCID: PMC5734746 DOI: 10.1371/journal.pone.0189018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2017] [Accepted: 11/18/2017] [Indexed: 11/19/2022] Open
Abstract
Burkholderia spp. are genetically and physiologically diverse. Some strains are naturally transformable and capable of DNA catabolism. Burkholderia pseudomallei (Bp) strains 1026b and K96243 and B. thailandensis strain E264 are able to utilize DNA as a sole carbon source for growth, while only strains 1026b and E264 are naturally transformable. In this study, we constructed low-copy broad-host-range fosmid library, containing Bp strain 1026b chromosomal DNA fragments, and employed a novel positive selection approach to identify genes responsible for DNA uptake and DNA catabolism. The library was transferred to non-competent Bp K96243 and B. cenocepacia (Bc) K56-2, harboring chromosomally-inserted FRT-flanked sacB and pheS counter-selection markers. The library was incubated with DNA encoding Flp recombinase, followed by counter-selection on sucrose and chlorinated phenylalanine, to select for clones that took up flp-DNA, transiently expressed Flp, and excised the sacB-pheS cassette. Putative clones that survived the counter-selection were subsequently incubated with gfp-DNA and bacteria were visualized via fluorescent microscopy to confirm natural competency. Fosmid sequencing identified several 1026b genes implicated in DNA uptake, which were validated using chromosomal mutants. One of the naturally competent clones selected in Bc K56-2 enabled Bc, Bp and B. mallei to utilize DNA as a sole carbon source, and all fosmids were used to successfully create mutations in non-naturally-competent B. mallei and Bp strains.
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Affiliation(s)
- Michael H. Norris
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, United States of America
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, HI, United States of America
- Department of Infectious Diseases and Pathology, University of Florida, Gainesville, Florida, United States of America
| | - Yun Heacock-Kang
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, United States of America
| | - Jan Zarzycki-Siek
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, United States of America
| | - Andrew P. Bluhm
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, United States of America
| | - Ian A. McMillan
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, United States of America
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, HI, United States of America
| | - Herbert P. Schweizer
- Department of Molecular Genetics and Microbiology, College of Medicine and Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America
| | - Tung T. Hoang
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, United States of America
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, HI, United States of America
- * E-mail:
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Heacock-Kang Y, Sun Z, Zarzycki-Siek J, McMillan IA, Norris MH, Bluhm AP, Cabanas D, Fogen D, Vo H, Donachie SP, Borlee BR, Sibley CD, Lewenza S, Schurr MJ, Schweizer HP, Hoang TT. Spatial transcriptomes within the Pseudomonas aeruginosa biofilm architecture. Mol Microbiol 2017; 106:976-985. [PMID: 29030956 PMCID: PMC5720903 DOI: 10.1111/mmi.13863] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/12/2017] [Indexed: 01/24/2023]
Abstract
Bacterial cooperative associations and dynamics in biofilm microenvironments are of special interest in recent years. Knowledge of localized gene‐expression and corresponding bacterial behaviors within the biofilm architecture at a global scale has been limited, due to a lack of robust technology to study limited number of cells in stratified layers of biofilms. With our recent pioneering developments in single bacterial cell transcriptomic analysis technology, we generated herein an unprecedented spatial transcriptome map of the mature in vitro Pseudomonas aeruginosa biofilm model, revealing contemporaneous yet altered bacterial behaviors at different layers within the biofilm architecture (i.e., surface, middle and interior of the biofilm). Many genes encoding unknown functions were highly expressed at the biofilm‐solid interphase, exposing a critical gap in the knowledge of their activities that may be unique to this interior niche. Several genes of unknown functions are critical for biofilm formation. The in vivo importance of these unknown proteins was validated in invertebrate (fruit fly) and vertebrate (mouse) models. We envisage the future value of this report to the community, in aiding the further pathophysiological understanding of P. aeruginosa biofilms. Our approach will open doors to the study of bacterial functional genomics of different species in numerous settings.
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Affiliation(s)
- Yun Heacock-Kang
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Zhenxin Sun
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Jan Zarzycki-Siek
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Ian A McMillan
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, USA.,Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Michael H Norris
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Andrew P Bluhm
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Darlene Cabanas
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Dawson Fogen
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Hung Vo
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Stuart P Donachie
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Bradley R Borlee
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Christopher D Sibley
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Canada
| | - Shawn Lewenza
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Canada
| | - Michael J Schurr
- Department of Immunology and Microbiology, University of Colorado, Aurora, CO, USA
| | - Herbert P Schweizer
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL, USA
| | - Tung T Hoang
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, USA.,Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, HI, USA
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Choline Catabolism in Burkholderia thailandensis Is Regulated by Multiple Glutamine Amidotransferase 1-Containing AraC Family Transcriptional Regulators. J Bacteriol 2016; 198:2503-14. [PMID: 27381916 PMCID: PMC4999938 DOI: 10.1128/jb.00372-16] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 06/30/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Burkholderia thailandensis is a soil-dwelling bacterium that shares many metabolic pathways with the ecologically similar, but evolutionarily distant, Pseudomonas aeruginosa Among the diverse nutrients it can utilize is choline, metabolizable to the osmoprotectant glycine betaine and subsequently catabolized as a source of carbon and nitrogen, similar to P. aeruginosa Orthologs of genes in the choline catabolic pathway in these two bacteria showed distinct differences in gene arrangement as well as an additional orthologous transcriptional regulator in B. thailandensis In this study, we showed that multiple glutamine amidotransferase 1 (GATase 1)-containing AraC family transcription regulators (GATRs) are involved in regulation of the B. thailandensis choline catabolic pathway (gbdR1, gbdR2, and souR). Using genetic analyses and sequencing the transcriptome in the presence and absence of choline, we identified the likely regulons of gbdR1 (BTH_II1869) and gbdR2 (BTH_II0968). We also identified a functional ortholog for P. aeruginosa souR, a GATR that regulates the metabolism of sarcosine to glycine. GbdR1 is absolutely required for expression of the choline catabolic locus, similar to P. aeruginosa GbdR, while GbdR2 is important to increase expression of the catabolic locus. Additionally, the B. thailandensis SouR ortholog (BTH_II0994) is required for catabolism of choline and its metabolites as carbon sources, whereas in P. aeruginosa, SouR function can by bypassed by GbdR. The strategy employed by B. thailandensis represents a distinct regulatory solution to control choline catabolism and thus provides both an evolutionary counterpoint and an experimental system to analyze the acquisition and regulation of this pathway during environmental growth and infection. IMPORTANCE Many proteobacteria that occupy similar environmental niches have horizontally acquired orthologous genes for metabolism of compounds useful in their shared environment. The arrangement and differential regulation of these components can help us understand both the evolution of these systems and the potential roles these pathways have in the biology of each bacterium. Here, we describe the transcriptome response of Burkholderia thailandensis to the eukaryote-enriched molecule choline, identify the regulatory pathway governing choline catabolism, and compare the pathway to that previously described for Pseudomonas aeruginosa These data support a multitiered regulatory network in B. thailandensis, with conserved orthologs in the select agents Burkholderia pseudomallei and Burkholderia mallei, as well as the opportunistic lung pathogens in the Burkholderia cepacia clade.
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Su S, Bangar H, Saldanha R, Pemberton A, Aronow B, Dean GE, Lamkin TJ, Hassett DJ. Construction and characterization of stable, constitutively expressed, chromosomal green and red fluorescent transcriptional fusions in the select agents, Bacillus anthracis, Yersinia pestis, Burkholderia mallei, and Burkholderia pseudomallei. Microbiologyopen 2014; 3:610-29. [PMID: 25044501 PMCID: PMC4234255 DOI: 10.1002/mbo3.192] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Revised: 05/23/2014] [Accepted: 05/29/2014] [Indexed: 11/09/2022] Open
Abstract
Here, we constructed stable, chromosomal, constitutively expressed, green and red fluorescent protein (GFP and RFP) as reporters in the select agents, Bacillus anthracis, Yersinia pestis, Burkholderia mallei, and Burkholderia pseudomallei. Using bioinformatic approaches and other experimental analyses, we identified P0253 and P1 as potent promoters that drive the optimal expression of fluorescent reporters in single copy in B. anthracis and Burkholderia spp. as well as their surrogate strains, respectively. In comparison, Y. pestis and its surrogate strain need two chromosomal copies of cysZK promoter (P2cysZK) for optimal fluorescence. The P0253-, P2cysZK-, and P1-driven GFP and RFP fusions were first cloned into the vectors pRP1028, pUC18R6KT-mini-Tn7T-Km, pmini-Tn7-gat, or their derivatives. The resultant constructs were delivered into the respective surrogates and subsequently into the select agent strains. The chromosomal GFP- and RFP-tagged strains exhibited bright fluorescence at an exposure time of less than 200 msec and displayed the same virulence traits as their wild-type parental strains. The utility of the tagged strains was proven by the macrophage infection assays and lactate dehydrogenase release analysis. Such strains will be extremely useful in high-throughput screens for novel compounds that could either kill these organisms, or interfere with critical virulence processes in these important bioweapon agents and during infection of alveolar macrophages.
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Affiliation(s)
- Shengchang Su
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of MedicineCincinnati, Ohio, 45267
| | - Hansraj Bangar
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of MedicineCincinnati, Ohio, 45267
| | | | | | - Bruce Aronow
- Division of Biomedical Informatics, Cincinnati Children's Hospital Medical CenterCincinnati, Ohio, 45229-3039
| | - Gary E Dean
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of MedicineCincinnati, Ohio, 45267
| | - Thomas J Lamkin
- Air Force Research Laboratory, 711th HPW/RHXBC, Molecular Signatures SectionWright-Patterson AFB, Ohio, 45433-7913
| | - Daniel J Hassett
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of MedicineCincinnati, Ohio, 45267
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9
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Sun Z, Kang Y, Norris MH, Troyer RM, Son MS, Schweizer HP, Dow SW, Hoang TT. Blocking phosphatidylcholine utilization in Pseudomonas aeruginosa, via mutagenesis of fatty acid, glycerol and choline degradation pathways, confirms the importance of this nutrient source in vivo. PLoS One 2014; 9:e103778. [PMID: 25068317 PMCID: PMC4113454 DOI: 10.1371/journal.pone.0103778] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Accepted: 07/02/2014] [Indexed: 12/26/2022] Open
Abstract
Pseudomonas aeruginosa can grow to very high-cell-density (HCD) during infection of the cystic fibrosis (CF) lung. Phosphatidylcholine (PC), the major component of lung surfactant, has been hypothesized to support HCD growth of P. aeruginosa in vivo. The phosphorylcholine headgroup, a glycerol molecule, and two long-chain fatty acids (FAs) are released by enzymatic cleavage of PC by bacterial phospholipase C and lipases. Three different bacterial pathways, the choline, glycerol, and fatty acid degradation pathways, are then involved in the degradation of these PC components. Here, we identified five potential FA degradation (Fad) related fadBA-operons (fadBA1-5, each encoding 3-hydroxyacyl-CoA dehydrogenase and acyl-CoA thiolase). Through mutagenesis and growth analyses, we showed that three (fadBA145) of the five fadBA-operons are dominant in medium-chain and long-chain Fad. The triple fadBA145 mutant also showed reduced ability to degrade PC in vitro. We have previously shown that by partially blocking Fad, via mutagenesis of fadBA5 and fadDs, we could significantly reduce the ability of P. aeruginosa to replicate on FA and PC in vitro, as well as in the mouse lung. However, no studies have assessed the ability of mutants, defective in choline and/or glycerol degradation in conjunction with Fad, to grow on PC or in vivo. Hence, we constructed additional mutants (ΔfadBA145ΔglpD, ΔfadBA145ΔbetAB, and ΔfadBA145ΔbetABΔglpD) significantly defective in the ability to degrade FA, choline, and glycerol and, therefore, PC. The analysis of these mutants in the BALB/c mouse lung infection model showed significant inability to utilize PC in vitro, resulted in decreased replication fitness and competitiveness in vivo compared to the complement strain, although there was little to no variation in typical virulence factor production (e.g., hemolysin, lipase, and protease levels). This further supports the hypothesis that lung surfactant PC serves as an important nutrient for P. aeruginosa during CF lung infection.
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Affiliation(s)
- Zhenxin Sun
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
| | - Yun Kang
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
| | - Michael H. Norris
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
| | - Ryan M. Troyer
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Mike S. Son
- Department of Biological Sciences, Plymouth State University, Plymouth, New Hampshire, United States of America
| | - Herbert P. Schweizer
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Steven W. Dow
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Tung T. Hoang
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
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10
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Zarzycki-Siek J, Norris MH, Kang Y, Sun Z, Bluhm AP, McMillan IA, Hoang TT. Elucidating the Pseudomonas aeruginosa fatty acid degradation pathway: identification of additional fatty acyl-CoA synthetase homologues. PLoS One 2013; 8:e64554. [PMID: 23737986 PMCID: PMC3667196 DOI: 10.1371/journal.pone.0064554] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Accepted: 04/16/2013] [Indexed: 01/22/2023] Open
Abstract
The fatty acid (FA) degradation pathway of Pseudomonas aeruginosa, an opportunistic pathogen, was recently shown to be involved in nutrient acquisition during BALB/c mouse lung infection model. The source of FA in the lung is believed to be phosphatidylcholine, the major component of lung surfactant. Previous research indicated that P. aeruginosa has more than two fatty acyl-CoA synthetase genes (fadD; PA3299 and PA3300), which are responsible for activation of FAs using ATP and coenzyme A. Through a bioinformatics approach, 11 candidate genes were identified by their homology to the Escherichia coli FadD in the present study. Four new homologues of fadD (PA1617, PA2893, PA3860, and PA3924) were functionally confirmed by their ability to complement the E. coli fadD mutant on FA-containing media. Growth phenotypes of 17 combinatorial fadD mutants on different FAs, as sole carbon sources, indicated that the four new fadD homologues are involved in FA degradation, bringing the total number of P. aeruginosa fadD genes to six. Of the four new homologues, fadD4 (PA1617) contributed the most to the degradation of different chain length FAs. Growth patterns of various fadD mutants on plant-based perfumery substances, citronellic and geranic acids, as sole carbon and energy sources indicated that fadD4 is also involved in the degradation of these plant-derived compounds. A decrease in fitness of the sextuple fadD mutant, relative to the ΔfadD1D2 mutant, was only observed during BALB/c mouse lung infection at 24 h.
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Affiliation(s)
- Jan Zarzycki-Siek
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
| | - Michael H. Norris
- Department of Molecular Bioscience and Bioengineering, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
| | - Yun Kang
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
| | - Zhenxin Sun
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
| | - Andrew P. Bluhm
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
| | - Ian A. McMillan
- Department of Molecular Bioscience and Bioengineering, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
| | - Tung T. Hoang
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
- Department of Molecular Bioscience and Bioengineering, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
- * E-mail:
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Norris MH, Propst KL, Kang Y, Dow SW, Schweizer HP, Hoang TT. The Burkholderia pseudomallei Δasd mutant exhibits attenuated intracellular infectivity and imparts protection against acute inhalation melioidosis in mice. Infect Immun 2011; 79:4010-8. [PMID: 21807903 PMCID: PMC3187240 DOI: 10.1128/iai.05044-11] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Accepted: 07/26/2011] [Indexed: 11/20/2022] Open
Abstract
Burkholderia pseudomallei, the cause of serious and life-threatening diseases in humans, is of national biodefense concern because of its potential use as a bioterrorism agent. This microbe is listed as a select agent by the CDC; therefore, development of vaccines is of significant importance. Here, we further investigated the growth characteristics of a recently created B. pseudomallei 1026b Δasd mutant in vitro, in a cell model, and in an animal model of infection. The mutant was typified by an inability to grow in the absence of exogenous diaminopimelate (DAP); upon single-copy complementation with a wild-type copy of the asd gene, growth was restored to wild-type levels. Further characterization of the B. pseudomallei Δasd mutant revealed a marked decrease in RAW264.7 murine macrophage cytotoxicity compared to the wild type and the complemented Δasd mutant. RAW264.7 cells infected by the Δasd mutant did not exhibit signs of cytopathology or multinucleated giant cell (MNGC) formation, which were observed in wild-type B. pseudomallei cell infections. The Δasd mutant was found to be avirulent in BALB/c mice, and mice vaccinated with the mutant were protected against acute inhalation melioidosis. Thus, the B. pseudomallei Δasd mutant may be a promising live attenuated vaccine strain and a biosafe strain for consideration of exclusion from the select agent list.
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Affiliation(s)
- Michael H. Norris
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Manoa, Hawaii 96822
| | - Katie L. Propst
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado 80523
| | | | - Steven W. Dow
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado 80523
| | - Herbert P. Schweizer
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado 80523
| | - Tung T. Hoang
- Department of Microbiology
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Manoa, Hawaii 96822
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Knockout and pullout recombineering for naturally transformable Burkholderia thailandensis and Burkholderia pseudomallei. Nat Protoc 2011; 6:1085-104. [PMID: 21738123 DOI: 10.1038/nprot.2011.346] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Phage λ-Red proteins are powerful tools for pulling and knocking out chromosomal fragments but have been limited to the γ-proteobacteria. Procedures are described here to easily knock out (KO) and pull out (PO) chromosomal DNA fragments from naturally transformable Burkholderia thailandensis and Burkholderia pseudomallei. This system takes advantage of published compliant counterselectable and selectable markers (sacB, pheS, gat and the arabinose-utilization operon) and λ-Red mutant proteins. pheS-gat (KO) or oriT-ColE1ori-gat-ori1600-rep (PO) PCR fragments are generated with flanking 40- to 45-bp homologies to targeted regions incorporated on PCR primers. One-step recombination is achieved by incubation of the PCR product with cells expressing λ-Red proteins and subsequent selection on glyphosate-containing medium. This procedure takes ~10 d and is advantageous over previously published protocols: (i) smaller PCR products reduce primer numbers and amplification steps, (ii) PO fragments suitable for downstream manipulation in Escherichia coli are obtained and (iii) chromosomal KO increases flexibility for downstream processing.
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13
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Galyov EE, Brett PJ, DeShazer D. Molecular insights into Burkholderia pseudomallei and Burkholderia mallei pathogenesis. Annu Rev Microbiol 2010; 64:495-517. [PMID: 20528691 DOI: 10.1146/annurev.micro.112408.134030] [Citation(s) in RCA: 192] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Burkholderia pseudomallei and Burkholderia mallei are closely related gram-negative bacteria that can cause serious diseases in humans and animals. This review summarizes the current and rapidly expanding knowledge on the specific virulence factors employed by these pathogens and their roles in the pathogenesis of melioidosis and glanders. In particular, the contributions of recently identified virulence factors are described in the context of the intracellular lifestyle of these pathogens. Throughout this review, unique and shared virulence features of B. pseudomallei and B. mallei are discussed.
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Affiliation(s)
- Edouard E Galyov
- Department of Infection, Immunity and Inflammation, MSB, University of Leicester, Leicester LE1 9HN, United Kingdom.
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Stable, site-specific fluorescent tagging constructs optimized for burkholderia species. Appl Environ Microbiol 2010; 76:7635-40. [PMID: 20851961 DOI: 10.1128/aem.01188-10] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Several vectors that facilitate stable fluorescent labeling of Burkholderia pseudomallei and Burkholderia thailandensis were constructed. These vectors combined the effectiveness of the mini-Tn7 site-specific transposition system with fluorescent proteins optimized for Burkholderia spp., enabling bacterial tracking during cellular infection.
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15
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Norris MH, Kang Y, Lu D, Wilcox BA, Hoang TT. Glyphosate resistance as a novel select-agent-compliant, non-antibiotic-selectable marker in chromosomal mutagenesis of the essential genes asd and dapB of Burkholderia pseudomallei. Appl Environ Microbiol 2009; 75:6062-75. [PMID: 19648360 PMCID: PMC2753064 DOI: 10.1128/aem.00820-09] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2009] [Accepted: 07/26/2009] [Indexed: 11/20/2022] Open
Abstract
Genetic manipulation of the category B select agents Burkholderia pseudomallei and Burkholderia mallei has been stifled due to the lack of compliant selectable markers. Hence, there is a need for additional select-agent-compliant selectable markers. We engineered a selectable marker based on the gat gene (encoding glyphosate acetyltransferase), which confers resistance to the common herbicide glyphosate (GS). To show the ability of GS to inhibit bacterial growth, we determined the effective concentrations of GS against Escherichia coli and several Burkholderia species. Plasmids based on gat, flanked by unique flip recombination target (FRT) sequences, were constructed for allelic-replacement. Both allelic-replacement approaches, one using the counterselectable marker pheS and the gat-FRT cassette and one using the DNA incubation method with the gat-FRT cassette, were successfully utilized to create deletions in the asd and dapB genes of wild-type B. pseudomallei strains. The asd and dapB genes encode an aspartate-semialdehyde dehydrogenase (BPSS1704, chromosome 2) and dihydrodipicolinate reductase (BPSL2941, chromosome 1), respectively. Mutants unable to grow on media without diaminopimelate (DAP) and other amino acids of this pathway were PCR verified. These mutants displayed cellular morphologies consistent with the inability to cross-link peptidoglycan in the absence of DAP. The B. pseudomallei 1026b Deltaasd::gat-FRT mutant was complemented with the B. pseudomallei asd gene on a site-specific transposon, mini-Tn7-bar, by selecting for the bar gene (encoding bialaphos/PPT resistance) with PPT. We conclude that the gat gene is one of very few appropriate, effective, and beneficial compliant markers available for Burkholderia select-agent species. Together with the bar gene, the gat cassette will facilitate various genetic manipulations of Burkholderia select-agent species.
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Affiliation(s)
- Michael H Norris
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii 96822, USA
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