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Badten AJ, Torres AG. Burkholderia pseudomallei Complex Subunit and Glycoconjugate Vaccines and Their Potential to Elicit Cross-Protection to Burkholderia cepacia Complex. Vaccines (Basel) 2024; 12:313. [PMID: 38543947 PMCID: PMC10975474 DOI: 10.3390/vaccines12030313] [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: 01/16/2024] [Revised: 03/12/2024] [Accepted: 03/14/2024] [Indexed: 04/01/2024] Open
Abstract
Burkholderia are a group of Gram-negative bacteria that can cause a variety of diseases in at-risk populations. B. pseudomallei and B. mallei, the etiological agents of melioidosis and glanders, respectively, are the two clinically relevant members of the B. pseudomallei complex (Bpc). The development of vaccines against Bpc species has been accelerated in recent years, resulting in numerous promising subunits and glycoconjugate vaccines incorporating a variety of antigens. However, a second group of pathogenic Burkholderia species exists known as the Burkholderia cepacia complex (Bcc), a group of opportunistic bacteria which tend to affect individuals with weakened immunity or cystic fibrosis. To date, there have been few attempts to develop vaccines to Bcc species. Therefore, the primary goal of this review is to provide a broad overview of the various subunit antigens that have been tested in Bpc species, their protective efficacy, study limitations, and known or suspected mechanisms of protection. Then, we assess the reviewed Bpc antigens for their amino acid sequence conservation to homologous proteins found in Bcc species. We propose that protective Bpc antigens with a high degree of Bpc-to-Bcc sequence conservation could serve as components of a pan-Burkholderia vaccine capable of protecting against both disease-causing groups.
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Affiliation(s)
- Alexander J. Badten
- Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA;
- Institute for Translational Sciences, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Alfredo G. Torres
- Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA;
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA
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2
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Arivuselvam R, Dera AA, Parween Ali S, Alraey Y, Saif A, Hani U, Arumugam Ramakrishnan S, Azeeze MSTA, Rajeshkumar R, Susil A, Harindranath H, Kumar BRP. Isolation, Identification, and Antibacterial Properties of Prodigiosin, a Bioactive Product Produced by a New Serratia marcescens JSSCPM1 Strain: Exploring the Biosynthetic Gene Clusters of Serratia Species for Biological Applications. Antibiotics (Basel) 2023; 12:1466. [PMID: 37760761 PMCID: PMC10526024 DOI: 10.3390/antibiotics12091466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Revised: 09/13/2023] [Accepted: 09/15/2023] [Indexed: 09/29/2023] Open
Abstract
Prodigiosin pigment has high medicinal value, so exploring this compound is a top priority. This report presents a prodigiosin bioactive compound isolated from Serratia marcescens JSSCPM1, a new strain. The purification process of this compound involves the application of different chromatographic methods, including UV-visible spectroscopy, high-performance liquid chromatography (HPLC), and liquid chromatography-mass spectrometry (LC/MS). Subsequent analysis was performed using nuclear magnetic resonance (NMR) to achieve a deeper understanding of the compound's structure. Finally, through a comprehensive review of the existing literature, the structural composition of the isolated bioactive compound was found to correspond to that of the well-known compound prodigiosin. The isolated prodigiosin compound was screened for antibacterial activity against both Gram-positive and Gram-negative bacteria. The compound inhibited the growth of Gram-negative bacterial strains compared with Gram-positive bacterial strains. It showed a maximum minimum inhibitory concentration against Escherichia coli NCIM 2065 at a 15.9 ± 0.31 μg/mL concentration. The potential binding capabilities between prodigiosin and the OmpF porin proteins (4GCS, 4GCP, and 4GCQ) were determined using in silico studies, which are generally the primary targets of different antibiotics. Comparative molecular docking analysis indicated that prodigiosin exhibits a good binding affinity toward these selected drug targets.
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Affiliation(s)
- Rajaguru Arivuselvam
- Department of Pharmaceutical Biotechnology, JSS College of Pharmacy, JSS Academy of Higher Education & Research, Ooty 643001, TN, India; (R.A.); (S.A.R.)
- Department of Pharmaceutical Biotechnology, JSS College of Pharmacy, JSS Academy of Higher Education & Research, Sri Shivarathreeshwara Nagar, Mysore 570015, KA, India
| | - Ayed A. Dera
- Department of Clinical Laboratory Sciences, Central Research Laboratory, College of Applied Medical Sciences, King Khalid University, Abha 62529, Saudi Arabia; (A.A.D.); (S.P.A.); (Y.A.)
| | - Syed Parween Ali
- Department of Clinical Laboratory Sciences, Central Research Laboratory, College of Applied Medical Sciences, King Khalid University, Abha 62529, Saudi Arabia; (A.A.D.); (S.P.A.); (Y.A.)
| | - Yasser Alraey
- Department of Clinical Laboratory Sciences, Central Research Laboratory, College of Applied Medical Sciences, King Khalid University, Abha 62529, Saudi Arabia; (A.A.D.); (S.P.A.); (Y.A.)
| | - Ahmed Saif
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Khalid University, Abha 62529, Saudi Arabia;
| | - Umme Hani
- Department of Pharmaceutics, College of Pharmacy, King Khalid University, Guraiger, Abha 62529, Saudi Arabia;
| | - Sivaa Arumugam Ramakrishnan
- Department of Pharmaceutical Biotechnology, JSS College of Pharmacy, JSS Academy of Higher Education & Research, Ooty 643001, TN, India; (R.A.); (S.A.R.)
- Department of Pharmaceutical Biotechnology, JSS College of Pharmacy, JSS Academy of Higher Education & Research, Sri Shivarathreeshwara Nagar, Mysore 570015, KA, India
| | | | - Raman Rajeshkumar
- Department of Pharmaceutical Biotechnology, JSS College of Pharmacy, JSS Academy of Higher Education & Research, Ooty 643001, TN, India; (R.A.); (S.A.R.)
| | - Aishwarya Susil
- Department of Pharmaceutical Chemistry, JSS College of Pharmacy, JSS Academy of Higher Education & Research, Sri Shivarathreeshwara Nagar, Mysore 570015, KA, India (H.H.)
| | - Haritha Harindranath
- Department of Pharmaceutical Chemistry, JSS College of Pharmacy, JSS Academy of Higher Education & Research, Sri Shivarathreeshwara Nagar, Mysore 570015, KA, India (H.H.)
| | - B. R. Prashantha Kumar
- Department of Pharmaceutical Chemistry, JSS College of Pharmacy, JSS Academy of Higher Education & Research, Sri Shivarathreeshwara Nagar, Mysore 570015, KA, India (H.H.)
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Hossain TJ, Das M, Ali F, Chowdhury SI, Zedny SA. Substrate preferences, phylogenetic and biochemical properties of proteolytic bacteria present in the digestive tract of Nile tilapia ( Oreochromis niloticus). AIMS Microbiol 2022; 7:528-545. [PMID: 35071947 PMCID: PMC8712536 DOI: 10.3934/microbiol.2021032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 12/20/2021] [Indexed: 12/31/2022] Open
Abstract
Vertebrate intestine appears to be an excellent source of proteolytic bacteria for industrial and probiotic use. We therefore aimed at obtaining the gut-associated proteolytic species of Nile tilapia (Oreochromis niloticus). We have isolated twenty six bacterial strains from its intestinal tract, seven of which showed exoprotease activity with the formation of clear halos on skim milk. Their depolymerization ability was further assessed on three distinct proteins including casein, gelatin, and albumin. All the isolates could successfully hydrolyze the three substrates indicating relatively broad specificity of their secreted proteases. Molecular taxonomy and phylogeny of the proteolytic isolates were determined based on their 16S rRNA gene barcoding, which suggested that the seven strains belong to three phyla viz. Firmicutes, Proteobacteria, and Actinobacteria, distributed across the genera Priestia, Citrobacter, Pseudomonas, Stenotrophomonas, Burkholderia, Providencia, and Micrococcus. The isolates were further characterized by a comprehensive study of their morphological, cultural, cellular and biochemical properties which were consistent with the phylogenetic annotations. To reveal their proteolytic capacity alongside substrate preferences, enzyme-production was determined by the diffusion assay. The Pseudomonas, Stenotrophomonas and Micrococcus isolates appeared to be most promising with maximum protease production on casein, gelatin, and albumin media respectively. Our findings present valuable insights into the phylogenetic and biochemical properties of gut-associated proteolytic strains of Nile tilapia.
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Affiliation(s)
- Tanim Jabid Hossain
- Department of Biochemistry and Molecular Biology, University of Chittagong, Chattogram 4331, Bangladesh.,Biochemistry and Pathogenesis of Microbes Research Group, Chattogram 4331, Bangladesh
| | - Mukta Das
- Department of Biochemistry and Molecular Biology, University of Chittagong, Chattogram 4331, Bangladesh.,Biochemistry and Pathogenesis of Microbes Research Group, Chattogram 4331, Bangladesh
| | - Ferdausi Ali
- Department of Microbiology, University of Chittagong, Chattogram 4331, Bangladesh
| | - Sumaiya Islam Chowdhury
- Department of Biochemistry and Molecular Biology, University of Chittagong, Chattogram 4331, Bangladesh.,Biochemistry and Pathogenesis of Microbes Research Group, Chattogram 4331, Bangladesh
| | - Subrina Akter Zedny
- Department of Biochemistry and Molecular Biology, University of Chittagong, Chattogram 4331, Bangladesh.,Biochemistry and Pathogenesis of Microbes Research Group, Chattogram 4331, Bangladesh
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Yip CH, Mahalingam S, Wan KL, Nathan S. Prodigiosin inhibits bacterial growth and virulence factors as a potential physiological response to interspecies competition. PLoS One 2021; 16:e0253445. [PMID: 34161391 PMCID: PMC8221495 DOI: 10.1371/journal.pone.0253445] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Accepted: 06/06/2021] [Indexed: 11/19/2022] Open
Abstract
Prodigiosin, a red linear tripyrrole pigment, has long been recognised for its antimicrobial property. However, the physiological contribution of prodigiosin to the survival of its producing hosts still remains undefined. Hence, the aim of this study was to investigate the biological role of prodigiosin from Serratia marcescens, particularly in microbial competition through its antimicrobial activity, towards the growth and secreted virulence factors of four clinical pathogenic bacteria (methicillin-resistant Staphylococcus aureus (MRSA), Enterococcus faecalis, Salmonella enterica serovar Typhimurium and Pseudomonas aeruginosa) as well as Staphylococcus aureus and Escherichia coli. Prodigiosin was first extracted from S. marcescens and its purity confirmed by absorption spectrum, high performance liquid chromatography (HPLC) and liquid chromatography-tandem mass spectrophotometry (LC-MS/MS). The extracted prodigiosin was antagonistic towards all the tested bacteria. A disc-diffusion assay showed that prodigiosin is more selective towards Gram-positive bacteria and inhibited the growth of MRSA, S. aureus and E. faecalis and Gram-negative E. coli. A minimum inhibitory concentration of 10 μg/μL of prodigiosin was required to inhibit the growth of S. aureus, E. coli and E. faecalis whereas > 10 μg/μL was required to inhibit MRSA growth. We further assessed the effect of prodigiosin towards bacterial virulence factors such as haemolysin and production of protease as well as on biofilm formation. Prodigiosin did not inhibit haemolysis activity of clinically associated bacteria but was able to reduce protease activity for MRSA, E. coli and E. faecalis as well as decrease E. faecalis, Salmonella Typhimurium and E. coli biofilm formation. Results of this study show that in addition to its role in inhibiting bacterial growth, prodigiosin also inhibits the bacterial virulence factor protease production and biofilm formation, two strategies employed by bacteria in response to microbial competition. As clinical pathogens were more resistant to prodigiosin, we propose that prodigiosin is physiologically important for S. marcescens to compete against other bacteria in its natural soil and surface water environments.
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Affiliation(s)
- Chee-Hoo Yip
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Selangor, Malaysia
| | - Sobina Mahalingam
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Selangor, Malaysia
| | - Kiew-Lian Wan
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Selangor, Malaysia
| | - Sheila Nathan
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Selangor, Malaysia
- * E-mail:
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Welkos S, Blanco I, Okaro U, Chua J, DeShazer D. A DUF4148 family protein produced inside RAW264.7 cells is a critical Burkholderia pseudomallei virulence factor. Virulence 2020; 11:1041-1058. [PMID: 32835600 PMCID: PMC7549894 DOI: 10.1080/21505594.2020.1806675] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 07/24/2020] [Accepted: 07/27/2020] [Indexed: 11/12/2022] Open
Abstract
Burkholderia pseudomallei: is the etiological agent of the disease melioidosis and is a Tier 1 select agent. It survives and replicates inside phagocytic cells by escaping from the endocytic vacuole, replicating in the cytosol, spreading to other cells via actin polymerization and promoting the fusion of infected and uninfected host cells to form multinucleated giant cells. In this study, we utilized a proteomics approach to identify bacterial proteins produced inside RAW264.7 murine macrophages and host proteins produced in response to B. pseudomallei infection. Cells infected with B. pseudomallei strain K96243 were lysed and the lysate proteins digested and analyzed using nanoflow reversed-phase liquid chromatography and tandem mass spectrometry. Approximately 160 bacterial proteins were identified in the infected macrophages, including BimA, TssA, TssB, Hcp1 and TssM. Several previously uncharacterized B. pseudomallei proteins were also identified, including BPSS1996 and BPSL2748. Mutations were constructed in the genes encoding these novel proteins and their relative virulence was assessed in BALB/c mice. The 50% lethal dose for the BPSS1996 mutant was approximately 55-fold higher than that of the wild type, suggesting that BPSS1996 is required for full virulence. Sera from B. pseudomallei-infected animals reacted with BPSS1996 and it was found to localize to the bacterial surface using indirect immunofluorescence. Finally, we identified 274 host proteins that were exclusively present or absent in infected RAW264.7 cells, including chemokines and cytokines involved in controlling the initial stages of infection.
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Affiliation(s)
- Susan Welkos
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, USA
| | - Irma Blanco
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, USA
| | - Udoka Okaro
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, USA
| | - Jennifer Chua
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, USA
| | - David DeShazer
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, USA
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6
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In vitro passage alters virulence, immune activation and proteomic profiles of Burkholderia pseudomallei. Sci Rep 2020; 10:8320. [PMID: 32433516 PMCID: PMC7239947 DOI: 10.1038/s41598-020-64914-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 02/27/2020] [Indexed: 11/12/2022] Open
Abstract
Serial passage is a problem among many bacterial species, especially those where strains have been stored (banked) for several decades. Prior to banking with an organization such as ATCC, many bacterial strains were passaged for many years, so the characteristics of each strain may be extremely different. This is in addition to any differences in the original host environment. For Burkholderia pseudomallei, the number of serial passages should be carefully defined for each experiment because it undergoes adaptation during the course of serial passages. In the present study, we found that passaged B. pseudomallei fresh clinical isolates and reference strain in Luria-Bertani broth exhibited increased plaque formation, invasion, intracellular replication, Galleria mellonella killing abilities, and cytokine production of host cells. These bacteria also modulated proteomic profiles during in vitro passage. We presume that the modulation of protein expression during in vitro passage caused changes in virulence and immunogenicity phenotypes. Therefore, we emphasize the need for caution regarding the use of data from passaged B. pseudomallei. These findings of phenotypic adaptation during in vitro serial passage can help researchers working on B. pseudomallei and on other species to better understand disparate findings among strains that have been reported for many years.
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7
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Burtnick MN, Brett PJ, DeShazer D. Proteomic analysis of the Burkholderia pseudomallei type II secretome reveals hydrolytic enzymes, novel proteins, and the deubiquitinase TssM. Infect Immun 2014; 82:3214-26. [PMID: 24866793 PMCID: PMC4136222 DOI: 10.1128/iai.01739-14] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 05/10/2014] [Indexed: 12/25/2022] Open
Abstract
Burkholderia pseudomallei, the etiologic agent of melioidosis, is an opportunistic pathogen that harbors a wide array of secretion systems, including a type II secretion system (T2SS), three type III secretion systems (T3SS), and six type VI secretion systems (T6SS). The proteins exported by these systems provide B. pseudomallei with a growth advantage in vitro and in vivo, but relatively little is known about the full repertoire of exoproducts associated with each system. In this study, we constructed deletion mutations in gspD and gspE, T2SS genes encoding an outer membrane secretin and a cytoplasmic ATPase, respectively. The secretion profiles of B. pseudomallei MSHR668 and its T2SS mutants were noticeably different when analyzed by SDS-PAGE. We utilized liquid chromatography-tandem mass spectrometry (LC-MS/MS) to identify proteins present in the supernatants of B. pseudomallei MSHR668 and B. pseudomallei ΔgspD grown in rich and minimal media. The MSHR668 supernatants contained 48 proteins that were either absent or substantially reduced in the supernatants of ΔgspD strains. Many of these proteins were putative hydrolytic enzymes, including 12 proteases, two phospholipases, and a chitinase. Biochemical assays validated the LC-MS/MS results and demonstrated that the export of protease, phospholipase C, and chitinase activities is T2SS dependent. Previous studies had failed to identify the mechanism of secretion of TssM, a deubiquitinase that plays an integral role in regulating the innate immune response. Here we present evidence that TssM harbors an atypical signal sequence and that its secretion is mediated by the T2SS. This study provides the first in-depth characterization of the B. pseudomallei T2SS secretome.
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Affiliation(s)
- Mary N Burtnick
- Department of Microbiology and Immunology, University of South Alabama, Mobile, Alabama, USA
| | - Paul J Brett
- Department of Microbiology and Immunology, University of South Alabama, Mobile, Alabama, USA
| | - David DeShazer
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, USA
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Statistical analysis of production of protease and esterase by a newly isolated Lysinibacillus fusiformis AU01: purification and application of protease in sub-culturing cell lines. ANN MICROBIOL 2014. [DOI: 10.1007/s13213-014-0833-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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9
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Cordova-Kreylos AL, Fernandez LE, Koivunen M, Yang A, Flor-Weiler L, Marrone PG. Isolation and characterization of Burkholderia rinojensis sp. nov., a non-Burkholderia cepacia complex soil bacterium with insecticidal and miticidal activities. Appl Environ Microbiol 2013; 79:7669-78. [PMID: 24096416 PMCID: PMC3837800 DOI: 10.1128/aem.02365-13] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Accepted: 09/14/2013] [Indexed: 02/05/2023] Open
Abstract
Isolate A396, a bacterium isolated from a Japanese soil sample demonstrated strong insecticidal and miticidal activities in laboratory bioassays. The isolate was characterized through biochemical methods, fatty acid methyl ester (FAME) analysis, sequencing of 16S rRNA, multilocus sequence typing and analysis, and DNA-DNA hybridization. FAME analysis matched A396 to Burkholderia cenocepacia, but this result was not confirmed by 16S rRNA or DNA-DNA hybridization. 16S rRNA sequencing indicated closest matches with B. glumae and B. plantarii. DNA-DNA hybridization experiments with B. plantarii, B. glumae, B. multivorans, and B. cenocepacia confirmed the low genetic similarity (11.5 to 37.4%) with known members of the genus. PCR-based screening showed that A396 lacks markers associated with members of the B. cepacia complex. Bioassay results indicated two mechanisms of action: through ingestion and contact. The isolate effectively controlled beet armyworms (Spodoptera exigua; BAW) and two-spotted spider mites (Tetranychus urticae; TSSM). In diet overlay bioassays with BAW, 1% to 4% (vol/vol) dilution of the whole-cell broth caused 97% to 100% mortality 4 days postexposure, and leaf disc treatment bioassays attained 75% ± 22% mortality 3 days postexposure. Contact bioassays led to 50% larval mortality, as well as discoloration, stunting, and failure to molt. TSSM mortality reached 93% in treated leaf discs. Activity was maintained in cell-free supernatants and after heat treatment (60°C for 2 h), indicating that a secondary metabolite or excreted thermostable enzyme might be responsible for the activity. Based on these results, we describe the novel species Burkholderia rinojensis, a good candidate for the development of a biocontrol product against insect and mite pests.
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Kennan RM, Wong W, Dhungyel OP, Han X, Wong D, Parker D, Rosado CJ, Law RHP, McGowan S, Reeve SB, Levina V, Powers GA, Pike RN, Bottomley SP, Smith AI, Marsh I, Whittington RJ, Whisstock JC, Porter CJ, Rood JI. The subtilisin-like protease AprV2 is required for virulence and uses a novel disulphide-tethered exosite to bind substrates. PLoS Pathog 2010; 6:e1001210. [PMID: 21124876 PMCID: PMC2991261 DOI: 10.1371/journal.ppat.1001210] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2010] [Accepted: 10/26/2010] [Indexed: 11/18/2022] Open
Abstract
Many bacterial pathogens produce extracellular proteases that degrade the extracellular matrix of the host and therefore are involved in disease pathogenesis. Dichelobacter nodosus is the causative agent of ovine footrot, a highly contagious disease that is characterized by the separation of the hoof from the underlying tissue. D. nodosus secretes three subtilisin-like proteases whose analysis forms the basis of diagnostic tests that differentiate between virulent and benign strains and have been postulated to play a role in virulence. We have constructed protease mutants of D. nodosus; their analysis in a sheep virulence model revealed that one of these enzymes, AprV2, was required for virulence. These studies challenge the previous hypothesis that the elastase activity of AprV2 is important for disease progression, since aprV2 mutants were virulent when complemented with aprB2, which encodes a variant that has impaired elastase activity. We have determined the crystal structures of both AprV2 and AprB2 and characterized the biological activity of these enzymes. These data reveal that an unusual extended disulphide-tethered loop functions as an exosite, mediating effective enzyme-substrate interactions. The disulphide bond and Tyr92, which was located at the exposed end of the loop, were functionally important. Bioinformatic analyses suggested that other pathogenic bacteria may have proteases that utilize a similar mechanism. In conclusion, we have used an integrated multidisciplinary combination of bacterial genetics, whole animal virulence trials in the original host, biochemical studies, and comprehensive analysis of crystal structures to provide the first definitive evidence that the extracellular secreted proteases produced by D. nodosus are required for virulence and to elucidate the molecular mechanism by which these proteases bind to their natural substrates. We postulate that this exosite mechanism may be used by proteases produced by other bacterial pathogens of both humans and animals.
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Affiliation(s)
- Ruth M. Kennan
- Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Clayton, Victoria, Australia
- Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Wilson Wong
- Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Clayton, Victoria, Australia
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Om P. Dhungyel
- Faculty of Veterinary Science, University of Sydney, Camden, New South Wales, Australia
| | - Xiaoyan Han
- Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Clayton, Victoria, Australia
- Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - David Wong
- Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Clayton, Victoria, Australia
- Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Dane Parker
- Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Clayton, Victoria, Australia
- Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Carlos J. Rosado
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Ruby H. P. Law
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Sheena McGowan
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Shane B. Reeve
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Vita Levina
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Glenn A. Powers
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Robert N. Pike
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Stephen P. Bottomley
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - A. Ian Smith
- Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Clayton, Victoria, Australia
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Ian Marsh
- Elizabeth Macarthur Agricultural Institute, NSW Department of Primary Industries, Camden, New South Wales, Australia
| | - Richard J. Whittington
- Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Clayton, Victoria, Australia
- Faculty of Veterinary Science, University of Sydney, Camden, New South Wales, Australia
| | - James C. Whisstock
- Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Clayton, Victoria, Australia
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Corrine J. Porter
- Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Clayton, Victoria, Australia
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
- * E-mail: (CJP); (JIR)
| | - Julian I. Rood
- Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Clayton, Victoria, Australia
- Department of Microbiology, Monash University, Clayton, Victoria, Australia
- * E-mail: (CJP); (JIR)
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11
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Suppiah J, Thimma JS, Cheah SH, Vadivelu J. Development and evaluation of polymerase chain reaction assay to detect Burkholderia genus and to differentiate the species in clinical specimens. FEMS Microbiol Lett 2010; 306:9-14. [PMID: 20345378 DOI: 10.1111/j.1574-6968.2010.01923.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Molecular-based techniques are becoming desirable as tools for identification of infectious diseases. Amongst the Burkholderia spp., there is a need to differentiate Burkholderia pseudomallei from Burkholderia cepacia, as misidentification could lead to false treatment of patients. In this study, conventional PCR assay targeting three genes was developed. Primers were designed for the amplification of Burkholderia genus-specific groEL gene, B. pseudomallei-specific mprA gene and B. cepacia-specific zmpA gene. The specificity and sensitivity of the assay was tested with 15 negative control strains and 71 Burkholderia spp. isolates including positive controls B. pseudomallei K96243 and ATCC B. cepacia strain. All B. pseudomallei strains were positive for groEL (139 bp) and mprA (162 bp), indicating a sensitivity of 100%. All B. cepacia strains produced amplicons for detection of groEL and zmpA (147 bp). Specificity using negative strains was 100%. In this study, a PCR assay specific for the detection of Burkholderia spp. and differentiation of the genus B. pseudomallei and B. cepacia was developed. The conventional assay has to be performed separately for each species due to the similar size of the PCR products amplified. This format may therefore be recommended for use as a diagnostic tool in laboratories where real-time PCR machines are not available. However, the real-time PCR was able to detect and differentiate the genus and species in single duplex assay.
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Affiliation(s)
- Jeyanthi Suppiah
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
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12
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Role for the Burkholderia pseudomallei capsular polysaccharide encoded by the wcb operon in acute disseminated melioidosis. Infect Immun 2009; 77:5252-61. [PMID: 19752033 DOI: 10.1128/iai.00824-09] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The capsular polysaccharide of Burkholderia pseudomallei is an essential virulence determinant that is required for protection from host serum cidal activity and opsonophagocytosis. In this study, the immune response directed against a B. pseudomallei capsule mutant (JW270) was investigated in an acute respiratory murine model. JW270 was significantly attenuated in this model ( approximately 2 logs) to levels resembling those of avirulent Burkholderia thailandensis. At lethal doses, JW270 colonized the lung, liver, and spleen at levels similar to the wild-type strain levels and was found to trigger reduced pathology in the liver and spleen. Several cytokine responses were altered in these tissues, and importantly, the levels of gamma interferon were reduced in the livers and spleens of JW270-infected mice but not in the lungs. These results suggest that the capsular polysaccharide of B. pseudomallei is a critical virulence determinant in respiratory tract infections and that it is an important antigen for generating the Th1 immune response commonly observed in systemic melioidosis. Furthermore, the data suggest that host recognition of B. pseudomallei capsular polysaccharide in the lungs may not be as important to the disease outcome as the innate immune response in the peripheral organs.
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13
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Lazar Adler NR, Govan B, Cullinane M, Harper M, Adler B, Boyce JD. The molecular and cellular basis of pathogenesis in melioidosis: how does Burkholderia pseudomallei cause disease? FEMS Microbiol Rev 2009; 33:1079-99. [PMID: 19732156 DOI: 10.1111/j.1574-6976.2009.00189.x] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Melioidosis, a febrile illness with disease states ranging from acute pneumonia or septicaemia to chronic abscesses, was first documented by Whitmore & Krishnaswami (1912). The causative agent, Burkholderia pseudomallei, was subsequently identified as a motile, gram-negative bacillus, which is principally an environmental saprophyte. Melioidosis has become an increasingly important disease in endemic areas such as northern Thailand and Australia (Currie et al., 2000). This health burden, plus the classification of B. pseudomallei as a category B biological agent (Rotz et al., 2002), has resulted in an escalation of research interest. This review focuses on the molecular and cellular basis of pathogenesis in melioidosis, with a comprehensive overview of the current knowledge on how B. pseudomallei can cause disease. The process of B. pseudomallei movement from the environmental reservoir to attachment and invasion of epithelial and macrophage cells and the subsequent intracellular survival and spread is outlined. Furthermore, the diverse assortment of virulence factors that allow B. pseudomallei to become an effective opportunistic pathogen, as well as to avoid or subvert the host immune response, is discussed. With the recent increase in genomic and molecular studies, the current understanding of the infection process of melioidosis has increased substantially, yet, much still remains to be elucidated.
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14
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Karbalaei-Heidari HR, Amoozegar MA, Hajighasemi M, Ziaee AA, Ventosa A. Production, optimization and purification of a novel extracellular protease from the moderately halophilic bacterium Halobacillus karajensis. J Ind Microbiol Biotechnol 2008; 36:21-7. [DOI: 10.1007/s10295-008-0466-y] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2008] [Accepted: 08/27/2008] [Indexed: 10/21/2022]
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15
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Comparative genomics and an insect model rapidly identify novel virulence genes of Burkholderia mallei. J Bacteriol 2008; 190:2306-13. [PMID: 18223084 DOI: 10.1128/jb.01735-07] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Burkholderia pseudomallei and its host-adapted deletion clone Burkholderia mallei cause the potentially fatal human diseases melioidosis and glanders, respectively. The antibiotic resistance profile and ability to infect via aerosol of these organisms and the absence of protective vaccines have led to their classification as major biothreats and select agents. Although documented infections by these bacteria date back over 100 years, relatively little is known about their virulence and pathogenicity mechanisms. We used in silico genomic subtraction to generate their virulome, a set of 650 putative virulence-related genes shared by B. pseudomallei and B. mallei but not present in five closely related nonpathogenic Burkholderia species. Although most of these genes are clustered in putative operons, the number of targets for mutant construction and verification of reduced virulence in animal models is formidable. Therefore, Galleria mellonella (wax moth) larvae were evaluated as a surrogate host; we found that B. pseudomallei and B. mallei, but not other phylogenetically related bacteria, were highly pathogenic for this insect. More importantly, four previously characterized B. mallei mutants with reduced virulence in hamsters or mice had similarly reduced virulence in G. mellonella larvae. Site-specific inactivation of selected genes in the computationally derived virulome identified three new potential virulence genes, each of which was required for rapid and efficient killing of larvae. Thus, this approach may provide a means to quickly identify high-probability virulence genes in B. pseudomallei, B. mallei, and other pathogens.
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16
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Neubauer H, Sprague LD, Joseph M, Tomaso H, Al Dahouk S, Witte A, Kinne J, Hensel A, Wernery R, Wernery U, Scholz HC. Development and clinical evaluation of a PCR assay targeting the metalloprotease gene (mprA) of B. pseudomallei. Zoonoses Public Health 2007; 54:44-50. [PMID: 17359446 DOI: 10.1111/j.1863-2378.2007.01008.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A PCR assay targeting the metalloprotease gene (mprA) of Burkholderia pseudomallei was developed for the specific detection of this organism in pure cultures and clinical samples. All other closely related organisms including B. mallei the causative agent of glanders, and B. thailandensis tested negative. Burkholderia pseudomallei DNA was successfully amplified from paraffin-embedded lung tissue of a camel with a generalized B. pseudomallei infection. The developed PCR assay can be used as a simple tool for the specific and sensitive detection of B. pseudomallei.
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Affiliation(s)
- H Neubauer
- Friedrich-Loeffler-Institut, Naumburger Str. 96a, D-07743 Jena, Germany.
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17
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The Burkholderia pseudomallei serine protease MprA is autoproteolytically activated to produce a highly stable enzyme. Enzyme Microb Technol 2007. [DOI: 10.1016/j.enzmictec.2006.09.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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18
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Diggle SP, Lumjiaktase P, Dipilato F, Winzer K, Kunakorn M, Barrett DA, Chhabra SR, Cámara M, Williams P. Functional genetic analysis reveals a 2-Alkyl-4-quinolone signaling system in the human pathogen Burkholderia pseudomallei and related bacteria. ACTA ACUST UNITED AC 2006; 13:701-10. [PMID: 16873018 DOI: 10.1016/j.chembiol.2006.05.006] [Citation(s) in RCA: 142] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2006] [Revised: 04/27/2006] [Accepted: 05/01/2006] [Indexed: 10/24/2022]
Abstract
Pseudomonas aeruginosa synthesizes diverse 2-alkyl-4(1H)-quinolones (AHQs), including the signaling molecule 2-heptyl-3-hydroxy-4(1H)-quinolone (PQS), via the pqsABCDE locus. By examining the genome databases, homologs of the pqs genes were identified in other bacteria. However, apart from P. aeruginosa, only Burkholderia pseudomallei and B. thailandensis contained a complete pqsA-E operon (termed hhqA-E). By introducing the B. pseudomallei hhqA and hhqE genes into P. aeruginosa pqsA and pqsE mutants, we show that they are functionally conserved and restore virulence factor and PQS production. B. pseudomallei, B. thailandensis, B. cenocepacia, and P. putida each produced 2-heptyl-4(1H)-quinolone (HHQ), but not PQS. Mutation of hhqA in B. pseudomallei resulted in the loss of AHQ production, altered colony morphology, and enhanced elastase production, which was reduced to parental levels by exogenous HHQ. These data reveal a role for AHQs in bacterial cell-to-cell communication beyond that seen in P. aeruginosa.
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Affiliation(s)
- Stephen P Diggle
- Institute of Infection, Immunity & Inflammation, Centre for Biomolecular Sciences, University Park, University of Nottingham, UK.
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19
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Karbalaei-Heidari HR, Ziaee AA, Amoozegar MA. Purification and biochemical characterization of a protease secreted by the Salinivibrio sp. strain AF-2004 and its behavior in organic solvents. Extremophiles 2006; 11:237-43. [PMID: 17072685 DOI: 10.1007/s00792-006-0031-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2006] [Accepted: 09/03/2006] [Indexed: 10/24/2022]
Abstract
A metalloprotease secreted by the moderately halophilic bacterium Salinivibrio sp. strain AF-2004 when the culture reached the stationary growth phase. This enzyme was purified to homogeneity by acetone precipitation and subsequent Q-Sepharose anion exchange and Sephacryl S-200 gel filtration chromatography. The apparent molecular mass of the protease was 31 kDa by SDS-PAGE, whereas it was estimated as approximately 29 kDa by Sephacryl S-200 gel filtration. The purified protease had a specific activity of 116.8 mumol of tyrosine/min per mg protein on casein. The optimum temperature and salinity of the enzyme were at 55 degrees C and 0-0.5 M NaCl, although at salinities up to 4 M NaCl activity still remained. The protease was stable and had a broad pH profile (5.0-10.0) with an optimum of 8.5 for casein hydrolysis. The enzyme was strongly inhibited by phenylmethyl sulfonylfluoride (PMSF), Pefabloc SC, chymostatin and also EDTA, indicating that it belongs to the class of serine metalloproteases. The protease in solutions containing water-soluble organic solvents or alcohols was more stable than that in the absence of organic solvents. These characteristics make it an ideal choice for applications in industrial processes containing organic solvents and/or salts.
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20
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Roy Chowdhury P, Heinemann JA. The general secretory pathway of Burkholderia gladioli pv. agaricicola BG164R is necessary for cavity disease in white button mushrooms. Appl Environ Microbiol 2006; 72:3558-65. [PMID: 16672503 PMCID: PMC1472315 DOI: 10.1128/aem.72.5.3558-3565.2006] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Cavity disease in white button mushrooms is caused by Burkholderia gladioli pv. agaricicola. We describe the isolation and characterization of six mutants of the strain BG164R that no longer cause this disease on mushrooms. The mutations were mapped to genes of the general secretory pathway (GSP). This is the first report of the association of the type II secretion pathway with a disease in mushrooms. Phenotypes of the six avirulent mutants were the following: an inability to degrade mushroom tissue, a highly reduced capacity to secrete chitinase and protease, and a reduced number of flagella. Using these mutants, we also made the novel observation that the factors causing mushroom tissue degradation, thereby leading to the expression of cavity disease, can be separated from mycelium inhibition because avirulent mutants continued to inhibit the growth of actively growing mushroom mycelia. The GSP locus of B. gladioli was subsequently cloned and mapped and compared to the same locus in closely related species, establishing that the genetic organization of the gsp operon of B. gladioli pv. agaricicola is consistent with that of other species of the genus. We also identify the most common indigenous bacterial population present in the mushroom fruit bodies from a New Zealand farm, one of which, Ewingella americana, was found to be an apparent antagonist of B. gladioli pv. agaricicola. While other investigators have reported enhanced disease symptoms due to interactions between endogenous and disease-causing bacteria in other mushroom diseases, to the best of our knowledge this is the first report of an antagonistic effect.
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Affiliation(s)
- Piklu Roy Chowdhury
- School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, New Zealand
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21
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Chan SW, Nathan S. Epitope mapping of Burkholderia pseudomallei serine metalloprotease: identification of serine protease epitope mimics. ACTA ACUST UNITED AC 2005; 43:37-44. [PMID: 15607634 DOI: 10.1016/j.femsim.2004.06.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2004] [Revised: 06/01/2004] [Accepted: 06/30/2004] [Indexed: 10/26/2022]
Abstract
Filamentous phage random peptide libraries were used to identify the epitopes of Burkholderia pseudomallei protease by panning against IgG polyclonal sera that exhibited protease neutralizing properties. The isolated fusion peptides presented a consensus peptide sequence, TKSMALSG, which closely resembles part of the active site sequence, 435GTSMATPHVAG445, of B. pseudomallei serine metalloprotease. By comparing the consensus sequence, TKSMALSG, with the predicted three-dimensional molecular model of B. pseudomallei serine metalloprotease, it appears that the potential antibody binding epitope was buried within the molecule. This active site was conformational whereby one continuous sub-region (SMA) was located between two discontinuous sub-regions, supplied by the flanking residues in the same polypeptide. All phages selected from the biopanning with IgG polyclonal sera showed good binding towards the polyclonal antibodies when compared to the negative control. In addition, these peptide-bearing phages showed competitive inhibition of B. pseudomallei serine metalloprotease binding to the polyclonal IgG.
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Affiliation(s)
- Shzu-Wei Chan
- Centre for Gene Analysis and Technology, School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor D.E., Malaysia
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22
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Warawa J, Woods DE. Type III secretion system cluster 3 is required for maximal virulence of Burkholderia pseudomallei in a hamster infection model. FEMS Microbiol Lett 2005; 242:101-8. [PMID: 15621426 DOI: 10.1016/j.femsle.2004.10.045] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2004] [Revised: 10/19/2004] [Accepted: 10/25/2004] [Indexed: 11/26/2022] Open
Abstract
Burkholderia pseudomallei, the etiological agent of melioidosis, is an animal pathogen capable of inducing a highly fatal septicemia. B. pseudomallei possesses three type III secretion system (TTSS) clusters, two of which (TTSS1 and TTSS2) are homologous to the TTSS of the plant pathogen Ralstonia solanacearum, and one (TTSS3) is homologous to the Salmonella SPI-1 mammalian pathogenicity island. We have demonstrated that TTSS3 is required for the full virulence of B. pseudomallei in a hamster model of infection. We have also examined the virulence of B. pseudomallei mutants deficient in several putative TTSS3 effector molecules, and found no significant attenuation of B. pseudomallei virulence in the hamster model.
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Affiliation(s)
- Jonathan Warawa
- Department of Microbiology and Infectious Diseases, University of Calgary Health Sciences Centre, 3330 Hospital Drive NW, Calgary, Alta., Canada T2N 4N1
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23
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Abstract
Melioidosis, caused by the gram-negative saprophyte Burkholderia pseudomallei, is a disease of public health importance in southeast Asia and northern Australia that is associated with high case-fatality rates in animals and humans. It has the potential for epidemic spread to areas where it is not endemic, and sporadic case reports elsewhere in the world suggest that as-yet-unrecognized foci of infection may exist. Environmental determinants of this infection, apart from a close association with rainfall, are yet to be elucidated. The sequencing of the genome of a strain of B. pseudomallei has recently been completed and will help in the further identification of virulence factors. The presence of specific risk factors for infection, such as diabetes, suggests that functional neutrophil defects are important in the pathogenesis of melioidosis; other studies have defined virulence factors (including a type III secretion system) that allow evasion of killing mechanisms by phagocytes. There is a possible role for cell-mediated immunity, but repeated environmental exposure does not elicit protective humoral or cellular immunity. A vaccine is under development, but economic constraints may make vaccination an unrealistic option for many regions of endemicity. Disease manifestations are protean, and no inexpensive, practical, and accurate rapid diagnostic tests are commercially available; diagnosis relies on culture of the organism. Despite the introduction of ceftazidime- and carbapenem-based intravenous treatments, melioidosis is still associated with a significant mortality attributable to severe sepsis and its complications. A long course of oral eradication therapy is required to prevent relapse. Studies exploring the role of preventative measures, earlier clinical identification, and better management of severe sepsis are required to reduce the burden of this disease.
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Affiliation(s)
- Allen C Cheng
- Menzies School of Health Research, Charles Darwin University, Darwin, Australia
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24
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Lee MA, Wang D, Yap EH. Detection and differentiation of Burkholderia pseudomallei, Burkholderia mallei and Burkholderia thailandensis by multiplex PCR. ACTA ACUST UNITED AC 2005; 43:413-7. [PMID: 15708316 DOI: 10.1016/j.femsim.2004.10.008] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2004] [Revised: 08/13/2004] [Accepted: 10/22/2004] [Indexed: 11/28/2022]
Abstract
Burkholderia pseudomallei, a Gram-negative bacterium that causes melioidosis may be differentiated from closely related species of Burkholderia mallei that causes glanders and non-pathogenic species of Burkholderia thailandensis by multiplex PCR. The multiplex PCR consists of primers that flank a 10-bp repetitive element in B. pseudomallei and B. mallei amplifying PCR fragment of varying sizes between 400-700 bp, a unique sequence in B. thailandensis amplifying a PCR fragment of 308 bp and the metalloprotease gene amplifying a PCR fragment of 245 bp in B. pseudomallei and B. thailandensis. The multiplex PCR not only can differentiate the three Burkholderia species but can also be used for epidemiological typing of B. pseudomallei and B. mallei strains.
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Affiliation(s)
- May-Ann Lee
- Centre for BioMedical Sciences, Defence Medical and Environment Research Institute, DSO National Laboratories 27 Medical Drive, Singapore 117510, Singapore.
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25
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Ong C, Ooi CH, Wang D, Chong H, Ng KC, Rodrigues F, Lee MA, Tan P. Patterns of large-scale genomic variation in virulent and avirulent Burkholderia species. Genome Res 2005; 14:2295-307. [PMID: 15520292 PMCID: PMC525689 DOI: 10.1101/gr.1608904] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The human diseases melioidosis and glanders are caused by the bacteria Burkholderia pseudomallei and B. mallei respectively, and both species are regarded as potential biowarfare agents. We used B. pseudomallei DNA microarrays to compare the genomes of several clinical and environmental isolates of B. pseudomallei, B. mallei, and B. thailandensis, a closely related but avirulent species. Open reading frames (ORFs) deleted between the three species were associated with diverse cellular functions, including nitrogen and iron metabolism, quorum sensing, and polysaccharide production. Deleted ORFs in B. mallei exhibited significant genomic clustering, whereas deletions in B. thailandensis were more uniformly dispersed, suggesting that B. mallei and B. thailandensis may have diverged from B. pseudomallei and each other via distinct mechanisms. The genomes of independent B. pseudomallei isolates were highly conserved with a large-scale variance of less than 3% between isolates, and at least three distinct molecular subtypes could be defined. An analysis of subtype-specific genomic regions suggests that DNA loss has played an important role in the evolutionary radiation of B. pseudomallei in the natural environment. Our results raise several hypotheses concerning the possible mechanisms underlying the diverse biological properties exhibited by members of the Burkholderia family.
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Affiliation(s)
- Catherine Ong
- Defense Medical and Environmental Research Institute, Singapore 169610, Republic of Singapore
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26
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Valade E, Thibault FM, Gauthier YP, Palencia M, Popoff MY, Vidal DR. The PmlI-PmlR quorum-sensing system in Burkholderia pseudomallei plays a key role in virulence and modulates production of the MprA protease. J Bacteriol 2004; 186:2288-94. [PMID: 15060030 PMCID: PMC412159 DOI: 10.1128/jb.186.8.2288-2294.2004] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Burkholderia pseudomallei is the causative agent of melioidosis, an often fatal infection of humans and animals. The virulence of this pathogen is thought to depend on a number of secreted proteins, including the MprA metalloprotease. We observed that MprA is produced upon entry into the stationary phase, when the cell density is high, and this prompted us to study cell density-dependent regulation in B. pseudomallei. A search of the B. pseudomallei genome led to identification of a quorum-sensing system involving the LuxI-LuxR homologs PmlI-PmlR. PmlI directed the synthesis of an N-acylhomoserine lactone identified as N-decanoylhomoserine lactone. A B. pseudomallei pmlI mutant was significantly less virulent than the parental strain in a murine model of infection by the intraperitoneal, subcutaneous, and intranasal routes. Inactivation of pmlI resulted in overproduction of MprA at the onset of the stationary phase. A wild-type phenotype was restored following complementation with pmlI or addition of cell-free culture supernatant. In contrast, there was no significant difference between the virulence of a B. pseudomallei mprA mutant and the virulence of the wild-type strain. These results suggest that the PmlI-PmlR quorum-sensing system of B. pseudomallei is essential for full virulence in a mouse model and downregulates the production of MprA at a high cell density.
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Affiliation(s)
- E Valade
- Unité de Microbiologie, Département de biologie des agents transmissibles, Centre de Recherches du Service de Santé des Armées Emile Pardé, 38702 La Tronche, France.
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Catara G, Ruggiero G, La Cara F, Digilio FA, Capasso A, Rossi M. A novel extracellular subtilisin-like protease from the hyperthermophile Aeropyrum pernix K1: biochemical properties, cloning, and expression. Extremophiles 2003; 7:391-9. [PMID: 12908102 DOI: 10.1007/s00792-003-0337-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2002] [Accepted: 05/06/2003] [Indexed: 10/26/2022]
Abstract
A novel extracellular serine protease designated Pernisine was purified to homogeneity and characterized from the archaeon Aeropyrum pernix K1. The molecular mass, estimated by SDS-PAGE analysis and by gel filtration chromatography, was about 34 kDa suggesting that the enzyme is monomeric. Pernisine was active in a broad range of pH (5.0-12.0) and temperature (60-120 degrees C) with maximal activity at 90 degrees C and between pH 8.0 and 9.0. In the presence of 1 mM CaCl(2) the activity, as a function of the temperature, reached a maximum at 90 degrees C but at 120 degrees C the enzyme retained almost 80% of its maximal activity. Activity inhibition studies suggest that the enzyme is a serine metalloprotease and biochemical data indicate that Pernisine is a subtilisin-like enzyme. The protease gene, identified from the sequenced genome of A. pernix, was amplified from total genomic DNA by PCR technique to construct the expression plasmid pGEX-Pernisine. The Pernisine, lacking the leader sequence, was expressed in Escherichia coli BL21 strain as a fusion protein with glutathione- S-transferase. The biochemical properties of the recombinant enzyme were found to be similar to those of the native enzyme.
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Affiliation(s)
- G Catara
- Institute of Protein Biochemistry, CNR, Via Marconi 10, 80125 Naples, Italy
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28
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Abstract
Melioidosis is an important public health problem in some regions, and a potential bioweapon. Recent reports confirm that it is endemic in China, Taiwan and Laos, but the true incidence in most countries is unknown, and the ecology poorly understood. Potable water was the source of two recent outbreaks. The epidemiology and clinical manifestations of the disease in Australia are similar to those in Thailand, although prostatic abscesses and neurological manifestations are more common and parotid abscesses less so. Mycotic aneurysms are not uncommon. Patients with cystic fibrosis are at risk of pulmonary melioidosis. Comparison with the avirulent Burkholderia thailandensis has identified capsular polysaccharide as an important virulence determinant in Burkholderia pseudomallei. Diagnosis still relies on culture, and a throat swab is a worthwhile sample. Several beta-lactams, such as meropenem, reduce the mortality, and long courses of cotrimoxazole-containing regimes are needed to prevent relapse. The value of adjunctive treatments, such as granulocyte colony-stimulating factor, warrants further evaluation.
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Affiliation(s)
- David A B Dance
- Public Health Laboratory, Derriford Hospital, Plymouth, Devon, UK.
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