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Trottmann F, Fiedler J, Ishida K, Ishida-Ito M, Little RF, Hertweck C. Bacterial Pathogen Channels Medium-Sized Fatty Acids into Malleicyprol Biosynthesis. ACS Chem Biol 2023; 18:1557-1563. [PMID: 37319349 DOI: 10.1021/acschembio.3c00188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Bacterial pathogens of the Burkholderia pseudomallei (BP) group cause life-threatening infections in both humans and animals. Critical for the virulence of these often antibiotic-resistant pathogens is the polyketide hybrid metabolite malleicyprol, which features two chains, a short cyclopropanol-substituted chain and a long hydrophobic alkyl chain. The biosynthetic origin of the latter has remained unknown. Here, we report the discovery of novel overlooked malleicyprol congeners with varied chain lengths and identify medium-sized fatty acids as polyketide synthase (PKS) starter units that constitute the hydrophobic carbon tails. Mutational and biochemical analyses show that a designated coenzyme A-independent fatty acyl-adenylate ligase (FAAL, BurM) is essential for recruiting and activating fatty acids in malleicyprol biosynthesis. In vitro reconstitution of the BurM-catalyzed PKS priming reaction and analysis of ACP-bound building blocks reveal a key role of BurM in the toxin assembly. Insights into the function and role of BurM hold promise for the development of enzyme inhibitors as novel antivirulence therapeutics to combat infections with BP pathogens.
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Affiliation(s)
- Felix Trottmann
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstraße 11a, 07745 Jena, Germany
| | - Jonas Fiedler
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstraße 11a, 07745 Jena, Germany
| | - Keishi Ishida
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstraße 11a, 07745 Jena, Germany
| | - Mie Ishida-Ito
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstraße 11a, 07745 Jena, Germany
| | - Rory F Little
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstraße 11a, 07745 Jena, Germany
| | - Christian Hertweck
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstraße 11a, 07745 Jena, Germany
- Natural Product Chemistry, Faculty of Biological Sciences, Friedrich Schiller University Jena, 07743 Jena, Germany
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Gonzales M, Plener L, Armengaud J, Armstrong N, Chabrière É, Daudé D. Lactonase-mediated inhibition of quorum sensing largely alters phenotypes, proteome, and antimicrobial activities in Burkholderia thailandensis E264. Front Cell Infect Microbiol 2023; 13:1190859. [PMID: 37333853 PMCID: PMC10272358 DOI: 10.3389/fcimb.2023.1190859] [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: 03/21/2023] [Accepted: 05/15/2023] [Indexed: 06/20/2023] Open
Abstract
Introduction Burkholderia thailandensis is a study model for Burkholderia pseudomallei, a highly virulent pathogen, known to be the causative agent of melioidosis and a potential bioterrorism agent. These two bacteria use an (acyl-homoserine lactone) AHL-mediated quorum sensing (QS) system to regulate different behaviors including biofilm formation, secondary metabolite productions, and motility. Methods Using an enzyme-based quorum quenching (QQ) strategy, with the lactonase SsoPox having the best activity on B. thailandensis AHLs, we evaluated the importance of QS in B. thailandensis by combining proteomic and phenotypic analyses. Results We demonstrated that QS disruption largely affects overall bacterial behavior including motility, proteolytic activity, and antimicrobial molecule production. We further showed that QQ treatment drastically decreases B. thailandensis bactericidal activity against two bacteria (Chromobacterium violaceum and Staphylococcus aureus), while a spectacular increase in antifungal activity was observed against fungi and yeast (Aspergillus niger, Fusarium graminearum and Saccharomyces cerevisiae). Discussion This study provides evidence that QS is of prime interest when it comes to understanding the virulence of Burkholderia species and developing alternative treatments.
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Affiliation(s)
- Mélanie Gonzales
- Aix Marseille Université, IRD, APHM, MEPHI, IHU-Méditerranée Infection, Marseille, France
- Gene&GreenTK, Marseille, France
| | | | - Jean Armengaud
- Université Paris-Saclay, CEA, INRAE, Département Médicaments et Technologies pour la Santé (DMTS), SPI, Bagnols-sur-Cèze, France
| | | | - Éric Chabrière
- Aix Marseille Université, IRD, APHM, MEPHI, IHU-Méditerranée Infection, Marseille, France
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Ghazali AK, Firdaus-Raih M, Uthaya Kumar A, Lee WK, Hoh CC, Nathan S. Transitioning from Soil to Host: Comparative Transcriptome Analysis Reveals the Burkholderia pseudomallei Response to Different Niches. Microbiol Spectr 2023; 11:e0383522. [PMID: 36856434 PMCID: PMC10100664 DOI: 10.1128/spectrum.03835-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 02/06/2023] [Indexed: 03/02/2023] Open
Abstract
Burkholderia pseudomallei, a soil and water saprophyte, is responsible for the tropical human disease melioidosis. A hundred years since its discovery, there is still much to learn about B. pseudomallei proteins that are essential for the bacterium's survival in and interaction with the infected host, as well as their roles within the bacterium's natural soil habitat. To address this gap, bacteria grown under conditions mimicking the soil environment were subjected to transcriptome sequencing (RNA-seq) analysis. A dual RNA-seq approach was used on total RNA from spleens isolated from a B. pseudomallei mouse infection model at 5 days postinfection. Under these conditions, a total of 1,434 bacterial genes were induced, with 959 induced in the soil environment and 475 induced in bacteria residing within the host. Genes encoding metabolism and transporter proteins were induced when the bacteria were present in soil, while virulence factors, metabolism, and bacterial defense mechanisms were upregulated during active infection of mice. On the other hand, capsular polysaccharide and quorum-sensing pathways were inhibited during infection. In addition to virulence factors, reactive oxygen species, heat shock proteins, siderophores, and secondary metabolites were also induced to assist bacterial adaptation and survival in the host. Overall, this study provides crucial insights into the transcriptome-level adaptations which facilitate infection by soil-dwelling B. pseudomallei. Targeting novel therapeutics toward B. pseudomallei proteins required for adaptation provides an alternative treatment strategy given its intrinsic antimicrobial resistance and the absence of a vaccine. IMPORTANCE Burkholderia pseudomallei, a soil-dwelling bacterium, is the causative agent of melioidosis, a fatal infectious disease of humans and animals. The bacterium has a large genome consisting of two chromosomes carrying genes that encode proteins with important roles for survival in diverse environments as well as in the infected host. While a general mechanism of pathogenesis has been proposed, it is not clear which proteins have major roles when the bacteria are in the soil and whether the same proteins are key to successful infection and spread. To address this question, we grew the bacteria in soil medium and then in infected mice. At 5 days postinfection, bacteria were recovered from infected mouse organs and their gene expression was compared against that of bacteria grown in soil medium. The analysis revealed a list of genes expressed under soil growth conditions and a different set of genes encoding proteins which may be important for survival, replication, and dissemination in an infected host. These proteins are a potential resource for understanding the full adaptation mechanism of this pathogen. In the absence of a vaccine for melioidosis and with treatment being reliant on combinatorial antibiotic therapy, these proteins may be ideal targets for designing antimicrobials to treat melioidosis.
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Affiliation(s)
- Ahmad-Kamal Ghazali
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia
| | - Mohd Firdaus-Raih
- Department of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia
- Institute of Systems Biology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia
| | - Asqwin Uthaya Kumar
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia
| | - Wei-Kang Lee
- Codon Genomics Sdn. Bhd., Seri Kembangan, Selangor, Malaysia
| | - Chee-Choong Hoh
- Codon Genomics Sdn. Bhd., Seri Kembangan, Selangor, Malaysia
| | - Sheila Nathan
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia
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Nyanasegran PK, Nathan S, Firdaus-Raih M, Muhammad NAN, Ng CL. Biofilm Signaling, Composition and Regulation in Burkholderia pseudomallei. J Microbiol Biotechnol 2023; 33:15-27. [PMID: 36451302 PMCID: PMC9899790 DOI: 10.4014/jmb.2207.07032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 10/10/2022] [Accepted: 10/11/2022] [Indexed: 12/04/2022]
Abstract
The incidence of melioidosis cases caused by the gram-negative pathogen Burkholderia pseudomallei (BP) is seeing an increasing trend that has spread beyond its previously known endemic regions. Biofilms produced by BP have been associated with antimicrobial therapy limitation and relapse melioidosis, thus making it urgently necessary to understand the mechanisms of biofilm formation and their role in BP biology. Microbial cells aggregate and enclose within a self-produced matrix of extracellular polymeric substances (EPSs) to form biofilm. The transition mechanism of bacterial cells from planktonic state to initiate biofilm formation, which involves the formation of surface attachment microcolonies and the maturation of the biofilm matrix, is a dynamic and complex process. Despite the emerging findings on the biofilm formation process, systemic knowledge on the molecular mechanisms of biofilm formation in BP remains fractured. This review provides insights into the signaling systems, matrix composition, and the biosynthesis regulation of EPSs (exopolysaccharide, eDNA and proteins) that facilitate the formation of biofilms in order to present an overview of our current knowledge and the questions that remain regarding BP biofilms.
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Affiliation(s)
| | - Sheila Nathan
- Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia
| | - Mohd Firdaus-Raih
- Institute of Systems Biology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia,Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia
| | - Nor Azlan Nor Muhammad
- Institute of Systems Biology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia
| | - Chyan Leong Ng
- Institute of Systems Biology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia,Corresponding author Phone: +03 8921 4561 Fax: +603 8921 3398 E-mail:
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Paauw A, Scholz HC, Mars-Groenendijk RH, Dekker LJM, Luider TM, van Leeuwen HC. Expression of virulence and antimicrobial related proteins in Burkholderia mallei and Burkholderia pseudomallei. PLoS Negl Trop Dis 2023; 17:e0011006. [PMID: 36607891 PMCID: PMC9821509 DOI: 10.1371/journal.pntd.0011006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 12/06/2022] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Burkholderia mallei and Burkholderia pseudomallei are both potential biological threat agents. Melioidosis caused by B. pseudomallei is endemic in Southeast Asia and Northern Australia, while glanders caused by B. mallei infections are rare. Here we studied the proteomes of different B. mallei and B. pseudomallei isolates to determine species specific characteristics. METHODS The expressed proteins of 5 B. mallei and 6 B. pseudomallei strains were characterized using liquid chromatography high-resolution tandem mass spectrometry (LC-HRMS/MS). Subsequently, expression of potential resistance and virulence related characteristics were analyzed and compared. RESULTS Proteome analysis can be used for the identification of B. mallei and B. pseudomallei. Both species were identified based on >60 discriminative peptides. Expression of proteins potentially involved in antimicrobial resistance, AmrAB-OprA, BpeAB-OprB, BpeEF-OprC, PenA as well as several other efflux pump related proteins and putative β-lactamases was demonstrated. Despite, the fact that efflux pump BpeAB-OprB was expressed in all isolates, no clear correlation with an antimicrobial phenotype and the efflux-pump could be established. Also consistent with the phenotypes, no amino acid mutations in PenA known to result in β-lactam resistance could be identified. In all studied isolates, the expression of virulence (related) factors Capsule-1 and T2SS was demonstrated. The expression of T6SS-1 was demonstrated in all 6 B. pseudomallei isolates and in 2 of the 5 B. mallei isolates. In all, except one B. pseudomallei isolate, poly-beta-1,6 N-acetyl-D-glucosamine export porin (Pga), important for biofilm formation, was detected, which were absent in the proteomes of B. mallei. Siderophores, iron binding proteins, malleobactin and malleilactone are possibly expressed in both species under standard laboratory growth conditions. Expression of multiple proteins from both the malleobactin and malleilactone polyketide synthase (PKS) and non-ribosomal peptide synthetase (NRPS) clusters was demonstrated in both species. All B. pseudomallei expressed at least seven of the nine proteins of the bactobolin synthase cluster (bactobolin, is a ribosome targeting antibiotic), while only in one B. mallei isolate expression of two proteins of this synthase cluster was identified. CONCLUSIONS Analyzing the expressed proteomes revealed differences between B. mallei and B. pseudomallei but also between isolates from the same species. Proteome analysis can be used not only to identify B. mallei and B. pseudomallei but also to characterize the presence of important factors that putatively contribute to the pathogenesis of B. mallei and B. pseudomallei.
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Affiliation(s)
- Armand Paauw
- Netherlands Organization for Applied Scientific Research TNO, Department of CBRN Protection, Rijswijk, The Netherlands
- * E-mail:
| | - Holger C. Scholz
- Centre for Biological Threats and Special Pathogens, Highly Pathogenic Microorganisms (ZBS 2), Robert Koch Institute, Berlin, Germany
| | - Roos H. Mars-Groenendijk
- Netherlands Organization for Applied Scientific Research TNO, Department of CBRN Protection, Rijswijk, The Netherlands
| | | | - Theo M. Luider
- Department of Neurology, Erasmus MC, Rotterdam, The Netherlands
| | - Hans C. van Leeuwen
- Netherlands Organization for Applied Scientific Research TNO, Department of CBRN Protection, Rijswijk, The Netherlands
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The Global Regulator MftR Controls Virulence and Siderophore Production in Burkholderia thailandensis. J Bacteriol 2022; 204:e0023722. [PMID: 36286517 PMCID: PMC9664960 DOI: 10.1128/jb.00237-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacterial pathogens face iron limitation in a host environment. To overcome this challenge, they produce siderophores, small iron-chelating molecules.
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Warhead assembly in a lethal pathogen. Nat Chem 2022; 14:848-850. [PMID: 35906403 DOI: 10.1038/s41557-022-01013-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Trottmann F, Ishida K, Ishida-Ito M, Kries H, Groll M, Hertweck C. Pathogenic bacteria remodel central metabolic enzyme to build a cyclopropanol warhead. Nat Chem 2022; 14:884-890. [PMID: 35906404 PMCID: PMC9359912 DOI: 10.1038/s41557-022-01005-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 06/20/2022] [Indexed: 11/09/2022]
Abstract
Bacteria of the Burkholderia pseudomallei (BP) group pose a global health threat, causing the infectious diseases melioidosis, a common cause of pneumonia and sepsis, and glanders, a contagious zoonosis. A trait of BP bacteria is a conserved gene cluster coding for the biosynthesis of polyketides (malleicyprols) with a reactive cyclopropanol unit that is critical for virulence. Enzymes building this warhead represent ideal targets for antivirulence strategies but the biochemical basis of cyclopropanol formation is unknown. Here we describe the formation of the malleicyprol warhead. We show that BurG, an unusual NAD+-dependent member of the ketol-acid reductoisomerase family, constructs the strained cyclopropanol ring. Biochemical assays and a suite of eight crystal structures of native and mutated BurG with bound analogues and inhibitors provide snapshots of each step of the complex reaction mechanism, involving a concealed oxidoreduction and a C-S bond cleavage. Our findings illustrate a remarkable case of neofunctionalisation, where a biocatalyst from central metabolism has been evolutionarily repurposed for warhead production in pathogens.
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Affiliation(s)
- Felix Trottmann
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute (Leibniz-HKI), Jena, Germany
| | - Keishi Ishida
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute (Leibniz-HKI), Jena, Germany
| | - Mie Ishida-Ito
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute (Leibniz-HKI), Jena, Germany
| | - Hajo Kries
- Junior Research Group Biosynthetic Design of Natural Products, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute (Leibniz-HKI), Jena, Germany
| | - Michael Groll
- Center for Protein Assemblies, Chemistry Department, Technical University Munich, Garching, Germany.
| | - Christian Hertweck
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute (Leibniz-HKI), Jena, Germany. .,Faculty of Biological Sciences, Friedrich Schiller University Jena, Jena, Germany.
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Aiosa N, Sinha A, Jaiyesimi OA, da Silva RR, Branda SS, Garg N. Metabolomics Analysis of Bacterial Pathogen Burkholderia thailandensis and Mammalian Host Cells in Co-culture. ACS Infect Dis 2022; 8:1646-1662. [PMID: 35767828 DOI: 10.1021/acsinfecdis.2c00233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The Tier 1 HHS/USDA Select Agent Burkholderia pseudomallei is a bacterial pathogen that is highly virulent when introduced into the respiratory tract and intrinsically resistant to many antibiotics. Transcriptomic- and proteomic-based methodologies have been used to investigate mechanisms of virulence employed by B. pseudomallei and Burkholderia thailandensis, a convenient surrogate; however, analysis of the pathogen and host metabolomes during infection is lacking. Changes in the metabolites produced can be a result of altered gene expression and/or post-transcriptional processes. Thus, metabolomics complements transcriptomics and proteomics by providing a chemical readout of a biological phenotype, which serves as a snapshot of an organism's physiological state. However, the poor signal from bacterial metabolites in the context of infection poses a challenge in their detection and robust annotation. In this study, we coupled mammalian cell culture-based metabolomics with feature-based molecular networking of mono- and co-cultures to annotate the pathogen's secondary metabolome during infection of mammalian cells. These methods enabled us to identify several key secondary metabolites produced by B. thailandensis during infection of airway epithelial and macrophage cell lines. Additionally, the use of in silico approaches provided insights into shifts in host biochemical pathways relevant to defense against infection. Using chemical class enrichment analysis, for example, we identified changes in a number of host-derived compounds including immune lipids such as prostaglandins, which were detected exclusively upon pathogen challenge. Taken together, our findings indicate that co-culture of B. thailandensis with mammalian cells alters the metabolome of both pathogen and host and provides a new dimension of information for in-depth analysis of the host-pathogen interactions underlying Burkholderia infection.
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Affiliation(s)
- Nicole Aiosa
- School of Chemistry and Biochemistry, Georgia Institute of Technology, 950 Atlantic Drive, Atlanta, Georgia 30332-2000, United States
| | - Anupama Sinha
- Biotechnology & Bioengineering, Sandia National Laboratories, 7011 East Avenue, Livermore, California 94550, United States
| | - Olakunle A Jaiyesimi
- School of Chemistry and Biochemistry, Georgia Institute of Technology, 950 Atlantic Drive, Atlanta, Georgia 30332-2000, United States
| | - Ricardo R da Silva
- School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Av. do Café─Vila Monte Alegre, 14040-903 Ribeirão Preto-SP, Brazil
| | - Steven S Branda
- Systems Biology, Sandia National Laboratories, 7011 East Avenue, Livermore, California 94550, United States
| | - Neha Garg
- School of Chemistry and Biochemistry, Georgia Institute of Technology, 950 Atlantic Drive, Atlanta, Georgia 30332-2000, United States.,Center for Microbial Dynamics and Infection, Georgia Institute of Technology, 311 Ferst Drive, ES&T, Atlanta, Georgia 30332, United States
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Methodological tools to study species of the genus Burkholderia. Appl Microbiol Biotechnol 2021; 105:9019-9034. [PMID: 34755214 PMCID: PMC8578011 DOI: 10.1007/s00253-021-11667-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 10/25/2021] [Accepted: 10/26/2021] [Indexed: 11/26/2022]
Abstract
Bacteria belonging to the Burkholderia genus are extremely versatile and diverse. They can be environmental isolates, opportunistic pathogens in cystic fibrosis, immunocompromised or chronic granulomatous disease patients, or cause disease in healthy people (e.g., Burkholderia pseudomallei) or animals (as in the case of Burkholderia mallei). Since the genus was separated from the Pseudomonas one in the 1990s, the methodological tools to study and characterize these bacteria are evolving fast. Here we reviewed the techniques used in the last few years to update the taxonomy of the genus, to study gene functions and regulations, to deepen the knowledge on the drug resistance which characterizes these bacteria, and to elucidate their mechanisms to establish infections. The availability of these tools significantly impacts the quality of research on Burkholderia and the choice of the most appropriated is fundamental for a precise characterization of the species of interest. Key points • Updated techniques to study the genus Burkholderia were reviewed. • Taxonomy, genomics, assays, and animal models were described. • A comprehensive overview on recent advances in Burkholderia studies was made.
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Covington BC, Xu F, Seyedsayamdost MR. A Natural Product Chemist's Guide to Unlocking Silent Biosynthetic Gene Clusters. Annu Rev Biochem 2021; 90:763-788. [PMID: 33848426 PMCID: PMC9148385 DOI: 10.1146/annurev-biochem-081420-102432] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Microbial natural products have provided an important source of therapeutic leads and motivated research and innovation in diverse scientific disciplines. In recent years, it has become evident that bacteria harbor a large, hidden reservoir of potential natural products in the form of silent or cryptic biosynthetic gene clusters (BGCs). These can be readily identified in microbial genome sequences but do not give rise to detectable levels of a natural product. Herein, we provide a useful organizational framework for the various methods that have been implemented for interrogating silent BGCs. We divide all available approaches into four categories. The first three are endogenous strategies that utilize the native host in conjunction with classical genetics, chemical genetics, or different culture modalities. The last category comprises expression of the entire BGC in a heterologous host. For each category, we describe the rationale, recent applications, and associated advantages and limitations.
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Affiliation(s)
- Brett C Covington
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA; ,
| | - Fei Xu
- Institute of Pharmaceutical Biotechnology and Department of Gastroenterology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China;
| | - Mohammad R Seyedsayamdost
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA; ,
- Department of Molecular Biology, Princeton University, New Jersey 08544, USA
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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] [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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Burkholderia thailandensis Methylated Hydroxyalkylquinolines: Biosynthesis and Antimicrobial Activity in Cocultures. Appl Environ Microbiol 2020; 86:AEM.01452-20. [PMID: 33008823 DOI: 10.1128/aem.01452-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 09/15/2020] [Indexed: 02/04/2023] Open
Abstract
The bacterium Burkholderia thailandensis produces an arsenal of secondary metabolites that have diverse structures and roles in the ecology of this soil-dwelling bacterium. In coculture experiments, B. thailandensis strain E264 secretes an antimicrobial that nearly eliminates another soil bacterium, Bacillus subtilis strain 168. To identify the antimicrobial, we used a transposon mutagenesis approach. This screen identified antimicrobial-defective mutants with insertions in the hmqA, hmqC, and hmqF genes involved in biosynthesis of a family of 2-alkyl-4(1H)-quinolones called 4-hydroxy-3-methyl-2-alkenylquinolines (HMAQs), which are closely related to the Pseudomonas aeruginosa 4-hydroxy-2-alkylquinolines (HAQs). Insertions also occurred in the previously uncharacterized gene BTH_II1576 ("hmqL"). The results confirm that BTH_II1576 is involved in generating N-oxide derivatives of HMAQs (HMAQ-NOs). Synthetic HMAQ-NO is active against B. subtilis 168, showing ∼50-fold more activity than HMAQ. Both the methyl group and the length of the carbon side chain account for the high activity of HMAQ-NO. The results provide new information on the biosynthesis and activities of HMAQs and reveal new insight into how these molecules might be important for the ecology of B. thailandensis IMPORTANCE The soil bacterium Burkholderia thailandensis produces 2-alkyl-4(1H)-quinolones that are mostly methylated 4-hydroxyalkenylquinolines, a family of relatively unstudied metabolites similar to molecules also synthesized by Pseudomonas aeruginosa Several of the methylated 4-hydroxyalkenylquinolines have antimicrobial activity against other species. We show that Bacillus subtilis strain 168 is particularly susceptible to N-oxidated methylalkenylquinolines (HMAQ-NOs). We confirmed that HMAQ-NO biosynthesis requires the previously unstudied protein HmqL. These results provide new information about the biology of 2-alkyl-4(1H)-quinolones, particularly the methylated 4-hydroxyalkenylquinolines, which are unique to B. thailandensis This study also has importance for understanding B. thailandensis secondary metabolites and has implications for potential therapeutic development.
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Williams PC, Wernke KM, Tirla A, Herzon SB. Employing chemical synthesis to study the structure and function of colibactin, a "dark matter" metabolite. Nat Prod Rep 2020; 37:1532-1548. [PMID: 33174565 PMCID: PMC7700718 DOI: 10.1039/d0np00072h] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Covering: 2015 to 2020 The field of natural products is dominated by a discovery paradigm that follows the sequence: isolation, structure elucidation, chemical synthesis, and then elucidation of mechanism of action and structure-activity relationships. Although this discovery paradigm has proven successful in the past, researchers have amassed enough evidence to conclude that the vast majority of nature's secondary metabolites - biosynthetic "dark matter" - cannot be identified and studied by this approach. Many biosynthetic gene clusters (BGCs) are expressed at low levels, or not at all, and in some instances a molecule's instability to fermentation or isolation prevents detection entirely. Here, we discuss an alternative approach to natural product identification that addresses these challenges by enlisting synthetic chemistry to prepare putative natural product fragments and structures as guided by biosynthetic insight. We demonstrate the utility of this approach through our structure elucidation of colibactin, an unisolable genotoxin produced by pathogenic bacteria in the human gut.
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Affiliation(s)
- Peyton C Williams
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, USA.
| | - Kevin M Wernke
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, USA.
| | - Alina Tirla
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, USA.
| | - Seth B Herzon
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, USA. and Department of Pharmacology, Yale School of Medicine, New Haven, Connecticut 06520, USA
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15
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Thapa SS, Grove A. Impaired purine homeostasis plays a primary role in trimethoprim-mediated induction of virulence genes in Burkholderia thailandensis. Mol Microbiol 2020; 115:610-622. [PMID: 33053234 DOI: 10.1111/mmi.14626] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 10/08/2020] [Accepted: 10/09/2020] [Indexed: 11/27/2022]
Abstract
One of the most commonly prescribed antibiotics against Burkholderia infections is co-trimoxazole, a cocktail of trimethoprim and sulfamethoxazole. Trimethoprim elicits an upregulation of the mal gene cluster, which encodes proteins involved in synthesis of the cytotoxic polyketide malleilactone; trimethoprim does so by increasing expression of the malR gene, which encodes the activator MalR. We report that B. thailandensis grown on trimethoprim exhibited increased virulence against Caenorhabditis elegans. This enhanced virulence correlated with an increase in expression of the mal gene cluster. Notably, inhibition of xanthine dehydrogenase by addition of allopurinol led to similar upregulation of malA and malR, with addition of trimethoprim or allopurinol also resulting in an equivalent intracellular accumulation of xanthine. Xanthine is a ligand for the transcription factor MftR that leads to attenuated DNA binding, and we show using chromatin immunoprecipitation that MftR binds directly to malR. Our gene expression data suggest that malR expression is repressed by both MftR and by a separate transcription factor, which also responds to a metabolite that accumulates on exposure to trimethoprim. Since allopurinol elicits a similar increase in malR/malA expression as trimethoprim, we suggest that impaired purine homeostasis plays a primary role in trimethoprim-mediated induction of malR and in turn malA.
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Affiliation(s)
- Sudarshan S Thapa
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, USA
| | - Anne Grove
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, USA
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16
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Secondary metabolites from the Burkholderia pseudomallei complex: structure, ecology, and evolution. J Ind Microbiol Biotechnol 2020; 47:877-887. [PMID: 33052546 DOI: 10.1007/s10295-020-02317-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 09/22/2020] [Indexed: 12/15/2022]
Abstract
Bacterial secondary metabolites play important roles in promoting survival, though few have been carefully studied in their natural context. Numerous gene clusters code for secondary metabolites in the genomes of members of the Bptm group, made up of three closely related species with distinctly different lifestyles: the opportunistic pathogen Burkholderia pseudomallei, the non-pathogenic saprophyte Burkholderia thailandensis, and the host-adapted pathogen Burkholderia mallei. Several biosynthetic gene clusters are conserved across two or all three species, and this provides an opportunity to understand how the corresponding secondary metabolites contribute to survival in different contexts in nature. In this review, we discuss three secondary metabolites from the Bptm group: bactobolin, malleilactone (and malleicyprol), and the 4-hydroxy-3-methyl-2-alkylquinolines, providing an overview of each of their biosynthetic pathways and insight into their potential ecological roles. Results of studies on these secondary metabolites provide a window into how secondary metabolites contribute to bacterial survival in different environments, from host infections to polymicrobial soil communities.
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17
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ScmR, a Global Regulator of Gene Expression, Quorum Sensing, pH Homeostasis, and Virulence in Burkholderia thailandensis. J Bacteriol 2020; 202:JB.00776-19. [PMID: 32312745 DOI: 10.1128/jb.00776-19] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 04/13/2020] [Indexed: 11/20/2022] Open
Abstract
The nonpathogenic soil saprophyte Burkholderia thailandensis is a member of the Burkholderia pseudomallei /B. thailandensis/B. mallei group, which also comprises the closely related human pathogens B. pseudomallei and Burkholderia mallei responsible for the melioidosis and glanders diseases, respectively. ScmR, a recently identified LysR-type transcriptional regulator in B. thailandensis, acts as a global transcriptional regulator throughout the stationary phase and modulates the production of a wide range of secondary metabolites, including N-acyl-l-homoserine lactones and 4-hydroxy-3-methyl-2-alkylquinolines and virulence in the Caenorhabditis elegans nematode worm host model, as well as several quorum sensing (QS)-dependent phenotypes. We have investigated the role of ScmR in B. thailandensis strain E264 during the exponential phase. We used RNA sequencing transcriptomic analyses to identify the ScmR regulon, which was compared to the QS-controlled regulon, showing a considerable overlap between the ScmR-regulated genes and those controlled by QS. We characterized several genes modulated by ScmR using quantitative reverse transcription-PCR or mini-CTX-lux transcriptional reporters, including the oxalate biosynthetic gene obc1 required for pH homeostasis, the orphan LuxR-type transcriptional regulator BtaR5-encoding gene, and the bsa (Burkholderia secretion apparatus) type III secretion system genes essential for both B. pseudomallei and B. mallei pathogenicity, as well as the scmR gene itself. We confirmed that the transcription of scmR is under QS control, presumably ensuring fine-tuned modulation of gene expression. Finally, we demonstrated that ScmR influences virulence using the fruit fly model host Drosophila melanogaster We conclude that ScmR represents a central component of the B. thailandensis QS regulatory network.IMPORTANCE Coordination of the expression of genes associated with bacterial virulence and environmental adaptation is often dependent on quorum sensing (QS). The QS circuitry of the nonpathogenic bacterium Burkholderia thailandensis, widely used as a model system for the study of the human pathogen Burkholderia pseudomallei, is complex. We found that the LysR-type transcriptional regulator, ScmR, which is highly conserved and involved in the control of virulence/survival factors in the Burkholderia genus, is a global regulator mediating gene expression through the multiple QS systems coexisting in B. thailandensis, as well as QS independently. We conclude that ScmR represents a key QS modulatory network element, ensuring tight regulation of the transcription of QS-controlled genes, particularly those required for acclimatization to the environment.
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18
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Trottmann F, Ishida K, Franke J, Stanišić A, Ishida‐Ito M, Kries H, Pohnert G, Hertweck C. Sulfonium Acids Loaded onto an Unusual Thiotemplate Assembly Line Construct the Cyclopropanol Warhead of a
Burkholderia
Virulence Factor. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202003958] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Felix Trottmann
- Department of Biomolecular Chemistry Leibniz Institute for Natural Product Research and Infection Biology (HKI) Beutenbergstrasse 11a 07745 Jena Germany
| | - Keishi Ishida
- Department of Biomolecular Chemistry Leibniz Institute for Natural Product Research and Infection Biology (HKI) Beutenbergstrasse 11a 07745 Jena Germany
| | - Jakob Franke
- Institute of Botany Leibniz University Hannover 30419 Hannover Germany
| | - Aleksa Stanišić
- Junior Research Group Biosynthetic Design of Natural Products Leibniz Institute for Natural Product Research and Infection Biology (HKI) Beutenbergstrasse 11a 07745 Jena Germany
| | - Mie Ishida‐Ito
- Department of Biomolecular Chemistry Leibniz Institute for Natural Product Research and Infection Biology (HKI) Beutenbergstrasse 11a 07745 Jena Germany
| | - Hajo Kries
- Junior Research Group Biosynthetic Design of Natural Products Leibniz Institute for Natural Product Research and Infection Biology (HKI) Beutenbergstrasse 11a 07745 Jena Germany
| | - Georg Pohnert
- Institute for Inorganic and Analytical Chemistry Friedrich Schiller University Jena 07743 Jena Germany
| | - Christian Hertweck
- Department of Biomolecular Chemistry Leibniz Institute for Natural Product Research and Infection Biology (HKI) Beutenbergstrasse 11a 07745 Jena Germany
- Natural Product Chemistry Faculty of Biological Sciences Friedrich Schiller University Jena 07743 Jena Germany
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19
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Trottmann F, Ishida K, Franke J, Stanišić A, Ishida-Ito M, Kries H, Pohnert G, Hertweck C. Sulfonium Acids Loaded onto an Unusual Thiotemplate Assembly Line Construct the Cyclopropanol Warhead of a Burkholderia Virulence Factor. Angew Chem Int Ed Engl 2020; 59:13511-13515. [PMID: 32314848 PMCID: PMC7496086 DOI: 10.1002/anie.202003958] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Indexed: 12/13/2022]
Abstract
Pathogenic bacteria of the Burkholderia pseudomallei group cause severe infectious diseases such as glanders and melioidosis. Malleicyprols were identified as important bacterial virulence factors, yet the biosynthetic origin of their cyclopropanol warhead has remained enigmatic. By a combination of mutational analysis and metabolomics we found that sulfonium acids, dimethylsulfoniumpropionate (DMSP) and gonyol, known as osmolytes and as crucial components in the global organosulfur cycle, are key intermediates en route to the cyclopropanol unit. Functional genetics and in vitro analyses uncover a specialized pathway to DMSP involving a rare prokaryotic SET‐domain methyltransferase for a cryptic methylation, and show that DMSP is loaded onto the NRPS‐PKS hybrid assembly line by an adenylation domain dedicated to zwitterionic starter units. Then, the megasynthase transforms DMSP into gonyol, as demonstrated by heterologous pathway reconstitution in E. coli.
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Affiliation(s)
- Felix Trottmann
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstrasse 11a, 07745, Jena, Germany
| | - Keishi Ishida
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstrasse 11a, 07745, Jena, Germany
| | - Jakob Franke
- Institute of Botany, Leibniz University Hannover, 30419, Hannover, Germany
| | - Aleksa Stanišić
- Junior Research Group Biosynthetic Design of Natural Products, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstrasse 11a, 07745, Jena, Germany
| | - Mie Ishida-Ito
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstrasse 11a, 07745, Jena, Germany
| | - Hajo Kries
- Junior Research Group Biosynthetic Design of Natural Products, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstrasse 11a, 07745, Jena, Germany
| | - Georg Pohnert
- Institute for Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, 07743, Jena, Germany
| | - Christian Hertweck
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstrasse 11a, 07745, Jena, Germany.,Natural Product Chemistry, Faculty of Biological Sciences, Friedrich Schiller University Jena, 07743, Jena, Germany
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20
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Mukherji R, Zhang S, Chowdhury S, Stallforth P. Chimeric LuxR Transcription Factors Rewire Natural Product Regulation. Angew Chem Int Ed Engl 2020; 59:6192-6195. [PMID: 31943579 PMCID: PMC7187462 DOI: 10.1002/anie.201914449] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 12/12/2019] [Indexed: 01/17/2023]
Abstract
LuxR-type transcriptional activator proteins frequently regulate the expression of biosynthetic gene clusters (BGCs). With only a fraction of bacterial BGCs being expressed under standard culturing conditions, modulation of LuxRs would provide a powerful approach to activate silent clusters. We show that by exploiting the modular nature of LuxR proteins, it is possible to construct functional chimeric LuxRs, which enables both the rewiring of quorum sensing systems and the activation of silent BGCs. Importantly, our strategy allowed us to identify the novel natural product pseudomonol from a bacterium of the genus Pseudomonas.
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Affiliation(s)
- Ruchira Mukherji
- Independent Junior Research Group Chemistry of Microbial CommunicationLeibniz Institute for Natural Product Research and Infection BiologyHans Knöll Institute (HKI)Beutenbergstrasse 11a07745JenaGermany
| | - Shuaibing Zhang
- Independent Junior Research Group Chemistry of Microbial CommunicationLeibniz Institute for Natural Product Research and Infection BiologyHans Knöll Institute (HKI)Beutenbergstrasse 11a07745JenaGermany
| | - Somak Chowdhury
- Independent Junior Research Group Chemistry of Microbial CommunicationLeibniz Institute for Natural Product Research and Infection BiologyHans Knöll Institute (HKI)Beutenbergstrasse 11a07745JenaGermany
| | - Pierre Stallforth
- Independent Junior Research Group Chemistry of Microbial CommunicationLeibniz Institute for Natural Product Research and Infection BiologyHans Knöll Institute (HKI)Beutenbergstrasse 11a07745JenaGermany
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21
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Mukherji R, Zhang S, Chowdhury S, Stallforth P. Chimeric LuxR Transcription Factors Rewire Natural Product Regulation. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201914449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Ruchira Mukherji
- Independent Junior Research Group Chemistry of Microbial CommunicationLeibniz Institute for Natural Product Research and Infection BiologyHans Knöll Institute (HKI) Beutenbergstrasse 11a 07745 Jena Germany
| | - Shuaibing Zhang
- Independent Junior Research Group Chemistry of Microbial CommunicationLeibniz Institute for Natural Product Research and Infection BiologyHans Knöll Institute (HKI) Beutenbergstrasse 11a 07745 Jena Germany
| | - Somak Chowdhury
- Independent Junior Research Group Chemistry of Microbial CommunicationLeibniz Institute for Natural Product Research and Infection BiologyHans Knöll Institute (HKI) Beutenbergstrasse 11a 07745 Jena Germany
| | - Pierre Stallforth
- Independent Junior Research Group Chemistry of Microbial CommunicationLeibniz Institute for Natural Product Research and Infection BiologyHans Knöll Institute (HKI) Beutenbergstrasse 11a 07745 Jena Germany
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22
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Chen YL, Hsu DW, Hsueh PT, Chen JA, Shih PJ, Lee S, Lin HH, Chen YS. Distinct Pathogenic Patterns of Burkholderia pseudomallei Isolates Selected from Caenorhabditis elegans and Dictyostelium discoideum Models. Am J Trop Med Hyg 2020; 101:736-745. [PMID: 31392941 DOI: 10.4269/ajtmh.19-0052] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Burkholderia pseudomallei is a selective agent that causes septic melioidosis and exhibits a broad range of lethal doses in animals. Host cellular virulence and phagocytic resistance are pathologic keys of B. pseudomallei. We first proposed Caenorhabditis elegans as the host cellular virulence model to mimic bacterial virulence against mammals and second established the resistance of B. pseudomallei to predation by Dictyostelium discoideum as the phagocytosis model. The saprophytic sepsis-causing Burkholderia sp. (B. pseudomallei, Burkholderia thailandensis, Burkholderia cenocepacia, and Burkholderia multivorans) exhibited different virulence patterns in both simple models, but B. pseudomallei was the most toxic. Using both models, attenuated isolates of B. pseudomallei were selected from a transposon-mutant library and a panel of environmental isolates and reconfirmed by in vitro mouse peritoneal exudate cell association and invasion assays. The distinct pathological patterns of melioidosis were inducted by different selected B. pseudomallei isolates. Fatal melioidosis was induced by the isolates with high virulence in both simple models within 4-5 day, whereas the low-virulence isolates resulted in prolonged survival greater than 30 day. Infection with the isolates having high resistance to D. discoideum predation but a low C. elegans killing effect led to 83% of mice with neurologic melioidosis. By contrast, infection with the isolates having low resistance to D. discoideum predation but high C. elegans killing effect led to 20% cases with inflammation in the salivary glands. Our results indicated that individual B. pseudomallei isolates selected from simple biological models contribute differently to disease progression and/or tissue tropism.
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Affiliation(s)
- Ya-Lei Chen
- Department of Biotechnology, National Kaohsiung Normal University, Kaohsiung, Taiwan
| | - Duen-Wei Hsu
- Department of Biotechnology, National Kaohsiung Normal University, Kaohsiung, Taiwan
| | - Pei-Tan Hsueh
- Department of Internal Medicine, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan
| | - Jou-An Chen
- Department of Biotechnology, National Kaohsiung Normal University, Kaohsiung, Taiwan
| | - Pei-Jyun Shih
- Department of Biotechnology, National Kaohsiung Normal University, Kaohsiung, Taiwan
| | - Susan Lee
- Department of Internal Medicine, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan
| | - Hsi-Hsun Lin
- School of Medicine, Institute of Public Health, National Yang-Ming University, Taipei, Taiwan.,Medical Research Department, General Clinical Research Center, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Yao-Shen Chen
- Department of Internal Medicine, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan.,Department of Internal Medicine, National Yang-Ming University, Taipei, Taiwan
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23
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Greenberg EP, Chandler JR, Seyedsayamdost MR. The Chemistry and Biology of Bactobolin: A 10-Year Collaboration with Natural Product Chemist Extraordinaire Jon Clardy. JOURNAL OF NATURAL PRODUCTS 2020; 83:738-743. [PMID: 32105069 PMCID: PMC8118907 DOI: 10.1021/acs.jnatprod.9b01237] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Bactobolin is a hybrid natural product with potent cytotoxic activity. Its production from Burkholderia thailandensis was reported as part of a collaboration between the Greenberg and Clardy laboratories in 2010. The collaboration sparked a series of studies leading to the discovery of new analogues and associated structure-activity relationships, the identification of the bactobolin biosynthetic gene cluster and assembly of its unusual amino acid building block, the molecular target of and resistance to the antibiotic, and finally an X-ray crystal structure of the ribosome-bactobolin complex. Herein, we review the collaborations that led to our current understanding of the chemistry and biology of bactobolin.
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Affiliation(s)
- E Peter Greenberg
- Department of Microbiology, School of Medicine, University of Washington, Seattle, Washington 98195, United States
| | - Josephine R Chandler
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas 66045, United States
| | - Mohammad R Seyedsayamdost
- Departments of Chemistry and Molecular Biology, Princeton University, Princeton, New Jersey 08544, United States
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24
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Multi-Omic Analyses Provide Links between Low-Dose Antibiotic Treatment and Induction of Secondary Metabolism in Burkholderia thailandensis. mBio 2020; 11:mBio.03210-19. [PMID: 32098820 PMCID: PMC7042699 DOI: 10.1128/mbio.03210-19] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Low doses of antibiotics can trigger secondary metabolite biosynthesis in bacteria, but the underlying mechanisms are generally unknown. We sought to better understand this phenomenon by studying how the antibiotic trimethoprim activates the synthesis of the virulence factor malleilactone in Burkholderia thailandensis Using transcriptomics, quantitative multiplexed proteomics, and primary metabolomics, we systematically mapped the changes induced by trimethoprim. Surprisingly, even subinhibitory doses of the antibiotic resulted in broad transcriptional and translational alterations, with ∼8.5% of the transcriptome and ∼5% of the proteome up- or downregulated >4-fold. Follow-up studies with genetic-biochemical experiments showed that the induction of malleilactone synthesis can be sufficiently explained by the accumulation of methionine biosynthetic precursors, notably homoserine, as a result of inhibition of the folate pathway. Homoserine activated the malleilactone gene cluster via the transcriptional regulator MalR and gave rise to a secondary metabolome which was very similar to that generated by trimethoprim. Our work highlights the expansive changes that low-dose trimethoprim induces on bacterial physiology and provides insights into its stimulatory effect on secondary metabolism.IMPORTANCE The discovery of antibiotics ranks among the most significant accomplishments of the last century. Although the targets of nearly all clinical antibiotics are known, our understanding regarding their natural functions and the effects of subinhibitory concentrations is in its infancy. Stimulatory rather than inhibitory functions have been attributed to low-dose antibiotics. Among these, we previously found that antibiotics activate silent biosynthetic genes and thereby enhance the metabolic output of bacteria. The regulatory circuits underlying this phenomenon are unknown. We take a first step toward elucidating these circuits and show that low doses of trimethoprim (Tmp) have cell-wide effects on the saprophyte Burkholderia thailandensis Most importantly, inhibition of one-carbon metabolic processes by Tmp leads to an accumulation of homoserine, which induces the production of an otherwise silent cytotoxin via a LuxR-type transcriptional regulator. These results provide a starting point for uncovering the molecular basis of the hormetic effects of antibiotics.
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25
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French CT, Bulterys PL, Woodward CL, Tatters AO, Ng KR, Miller JF. Virulence from the rhizosphere: ecology and evolution of Burkholderia pseudomallei-complex species. Curr Opin Microbiol 2020; 54:18-32. [PMID: 32028234 DOI: 10.1016/j.mib.2019.12.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 12/30/2019] [Indexed: 12/19/2022]
Affiliation(s)
- Christopher T French
- California NanoSystems Institute, UCLA, 570 Westwood Plaza Bldg. 114, 4538 West, Los Angeles, CA 90095, United States; Department of Microbiology, Immunology, and Molecular Genetics, UCLA, 609 Charles E. Young Drive East, Los Angeles, CA 90095, United States; Northern Arizona University, Department of Biological Sciences, Pathogen and Microbiome Institute 1395 S Knoles Drive, Flagstaff, AZ 86011, United States.
| | - Philip L Bulterys
- Department of Pathology, Stanford University, Lane Building, L235, 300 Pasteur Drive, Stanford, CA, 94305, United States
| | - Cora L Woodward
- California NanoSystems Institute, UCLA, 570 Westwood Plaza Bldg. 114, 4538 West, Los Angeles, CA 90095, United States
| | - Avery O Tatters
- California NanoSystems Institute, UCLA, 570 Westwood Plaza Bldg. 114, 4538 West, Los Angeles, CA 90095, United States
| | - Ken R Ng
- California NanoSystems Institute, UCLA, 570 Westwood Plaza Bldg. 114, 4538 West, Los Angeles, CA 90095, United States
| | - Jeff F Miller
- California NanoSystems Institute, UCLA, 570 Westwood Plaza Bldg. 114, 4538 West, Los Angeles, CA 90095, United States; Molecular Biology Institute, UCLA, 611 Charles E. Young Drive East, Los Angeles, CA 90095, United States; Department of Microbiology, Immunology, and Molecular Genetics, UCLA, 609 Charles E. Young Drive East, Los Angeles, CA 90095, United States
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26
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Thapa SS, Grove A. Do Global Regulators Hold the Key to Production of Bacterial Secondary Metabolites? Antibiotics (Basel) 2019; 8:antibiotics8040160. [PMID: 31547528 PMCID: PMC6963729 DOI: 10.3390/antibiotics8040160] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 09/18/2019] [Accepted: 09/19/2019] [Indexed: 12/18/2022] Open
Abstract
The emergence of multiple antibiotic resistant bacteria has pushed the available pool of antibiotics to the brink. Bacterial secondary metabolites have long been a valuable resource in the development of antibiotics, and the genus Burkholderia has recently emerged as a source of novel compounds with antibacterial, antifungal, and anti-cancer activities. Genome mining has contributed to the identification of biosynthetic gene clusters, which encode enzymes that are responsible for synthesis of such secondary metabolites. Unfortunately, these large gene clusters generally remain silent or cryptic under normal laboratory settings, which creates a hurdle in identification and isolation of these compounds. Various strategies, such as changes in growth conditions and antibiotic stress, have been applied to elicit the expression of these cryptic gene clusters. Although a number of compounds have been isolated from different Burkholderia species, the mechanisms by which the corresponding gene clusters are regulated remain poorly understood. This review summarizes the activity of well characterized secondary metabolites from Burkholderia species and the role of local regulators in their synthesis, and it highlights recent evidence for the role of global regulators in controlling production of secondary metabolites. We suggest that targeting global regulators holds great promise for the awakening of cryptic gene clusters and for developing better strategies for discovery of novel antibiotics.
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Affiliation(s)
- Sudarshan Singh Thapa
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA.
| | - Anne Grove
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA.
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27
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Trottmann F, Franke J, Richter I, Ishida K, Cyrulies M, Dahse H, Regestein L, Hertweck C. Cyclopropanol Warhead in Malleicyprol Confers Virulence of Human‐ and Animal‐Pathogenic
Burkholderia
Species. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201907324] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Felix Trottmann
- Department of Biomolecular Chemistry Leibniz Institute for Natural Product Research and Infection Biology (HKI) Beutenbergstr. 11a 07745 Jena Germany
| | - Jakob Franke
- Institute of Organic Chemistry, BMWZ Leibniz University Hannover 30167 Hannover Germany
| | - Ingrid Richter
- Department of Biomolecular Chemistry Leibniz Institute for Natural Product Research and Infection Biology (HKI) Beutenbergstr. 11a 07745 Jena Germany
| | - Keishi Ishida
- Department of Biomolecular Chemistry Leibniz Institute for Natural Product Research and Infection Biology (HKI) Beutenbergstr. 11a 07745 Jena Germany
| | - Michael Cyrulies
- Department Bio Pilot Plant Leibniz Institute for Natural Product Research and Infection Biology (HKI) 07745 Jena Germany
| | - Hans‐Martin Dahse
- Department Infection Biology Leibniz Institute for Natural Product Research and Infection Biology (HKI) 07745 Jena Germany
| | - Lars Regestein
- Department Bio Pilot Plant Leibniz Institute for Natural Product Research and Infection Biology (HKI) 07745 Jena Germany
| | - Christian Hertweck
- Department of Biomolecular Chemistry Leibniz Institute for Natural Product Research and Infection Biology (HKI) Beutenbergstr. 11a 07745 Jena Germany
- Natural Product Chemistry Faculty of Biological Sciences Friedrich Schiller University Jena 07743 Jena Germany
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Trottmann F, Franke J, Richter I, Ishida K, Cyrulies M, Dahse HM, Regestein L, Hertweck C. Cyclopropanol Warhead in Malleicyprol Confers Virulence of Human- and Animal-Pathogenic Burkholderia Species. Angew Chem Int Ed Engl 2019; 58:14129-14133. [PMID: 31353766 PMCID: PMC6790655 DOI: 10.1002/anie.201907324] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 07/20/2019] [Indexed: 12/16/2022]
Abstract
Burkholderia species such as B. mallei and B. pseudomallei are bacterial pathogens causing fatal infections in humans and animals (glanders and melioidosis), yet knowledge on their virulence factors is limited. While pathogenic effects have been linked to a highly conserved gene locus (bur/mal) in the B. mallei group, the metabolite associated to the encoded polyketide synthase, burkholderic acid (syn. malleilactone), could not explain the observed phenotypes. By metabolic profiling and molecular network analyses of the model organism B. thailandensis, the primary products of the cryptic pathway were identified as unusual cyclopropanol-substituted polyketides. First, sulfomalleicyprols were identified as inactive precursors of burkholderic acid. Furthermore, a highly reactive upstream metabolite, malleicyprol, was discovered and obtained in two stabilized forms. Cell-based assays and a nematode infection model showed that the rare natural product confers cytotoxicity and virulence.
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Affiliation(s)
- Felix Trottmann
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstr. 11a, 07745, Jena, Germany
| | - Jakob Franke
- Institute of Organic Chemistry, BMWZ, Leibniz University Hannover, 30167, Hannover, Germany
| | - Ingrid Richter
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstr. 11a, 07745, Jena, Germany
| | - Keishi Ishida
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstr. 11a, 07745, Jena, Germany
| | - Michael Cyrulies
- Department Bio Pilot Plant, Leibniz Institute for Natural Product Research and Infection Biology (HKI), 07745, Jena, Germany
| | - Hans-Martin Dahse
- Department Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology (HKI), 07745, Jena, Germany
| | - Lars Regestein
- Department Bio Pilot Plant, Leibniz Institute for Natural Product Research and Infection Biology (HKI), 07745, Jena, Germany
| | - Christian Hertweck
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstr. 11a, 07745, Jena, Germany.,Natural Product Chemistry, Faculty of Biological Sciences, Friedrich Schiller University Jena, 07743, Jena, Germany
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DeShazer D, Lovett S, Richardson J, Koroleva G, Kuehl K, Amemiya K, Sun M, Worsham P, Welkos S. Bacteriophage-associated genes responsible for the widely divergent phenotypes of variants of Burkholderia pseudomallei strain MSHR5848. J Med Microbiol 2019; 68:263-278. [PMID: 30628877 DOI: 10.1099/jmm.0.000908] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
PURPOSE Burkholderia pseudomallei, the tier 1 agent of melioidosis, is a saprophytic microbe that causes endemic infections in tropical regions such as South-East Asia and Northern Australia. It is globally distributed, challenging to diagnose and treat, infectious by several routes including inhalation, and has potential for adversarial use. B. pseudomallei strain MSHR5848 produces two colony variants, smooth (S) and rough (R), which exhibit a divergent range of morphological, biochemical and metabolic phenotypes, and differ in macrophage and animal infectivity. We aimed to characterize two major phenotypic differences, analyse gene expression and study the regulatory basis of the variation. METHODOLOGY Phenotypic expression was characterized by DNA and RNA sequencing, microscopy, and differential bacteriology. Regulatory genes were identified by cloning and bioinformatics.Results/Key findings. Whereas S produced larger quantities of extracellular DNA, R was upregulated in the production of a unique chromosome 1-encoded Siphoviridae-like bacteriophage, φMSHR5848. Exploratory transcriptional analyses revealed significant differences in variant expression of genes encoding siderophores, pili assembly, type VI secretion system cluster 4 (T6SS-4) proteins, several exopolysaccharides and secondary metabolites. A single 3 base duplication in S was the only difference that separated the variants genetically. It occurred upstream of a cluster of bacteriophage-associated genes on chromosome 2 that were upregulated in S. The first two genes were involved in regulating expression of the multiple phenotypes distinguishing S and R. CONCLUSION Bacteriophage-associated proteins have a major role in the phenotypic expression of MSHR5848. The goals are to determine the regulatory basis of this phenotypic variation and its role in pathogenesis and environmental persistence of B. pseudomallei.
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Affiliation(s)
- David DeShazer
- 1Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD, USA
| | - Sean Lovett
- 2Center for Genome Sciences, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD, USA
| | - Joshua Richardson
- 2Center for Genome Sciences, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD, USA
| | - Galina Koroleva
- 2Center for Genome Sciences, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD, USA.,†Present address: Room 7N109, Center for Human Immunology, Autoimmunity and Inflammation, National Institute of Allergy and Infectious Diseases, 10 Center Drive, Bethesda, MD 20814, USA
| | - Kathleen Kuehl
- 3Pathology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD, USA
| | - Kei Amemiya
- 1Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD, USA
| | - Mei Sun
- 4United States Army Medical Research and Materiel Command (USAMRMC), Frederick, MD, USA
| | - Patricia Worsham
- 1Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD, USA
| | - Susan Welkos
- 1Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD, USA
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