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Hu T, Yang X, Zhu Y, Liu F, Yang X, Xiong Z, Liang J, Lin Z, Ran Y, Guddat LW, Rao Z, Zhang B. Molecular basis for substrate transport of Mycobacterium tuberculosis ABC importer DppABCD. SCIENCE ADVANCES 2024; 10:eadk8521. [PMID: 38507491 PMCID: PMC10954201 DOI: 10.1126/sciadv.adk8521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 02/15/2024] [Indexed: 03/22/2024]
Abstract
The type I adenosine 5'-triphosphate (ATP)-binding cassette (ABC) transporter DppABCD is believed to be responsible for the import of exogenous heme as an iron source into the cytoplasm of the human pathogen Mycobacterium tuberculosis (Mtb). Additionally, this system is also known to be involved in the acquisition of tri- or tetra-peptides. Here, we report the cryo-electron microscopy structures of the dual-function Mtb DppABCD transporter in three forms, namely, the apo, substrate-bound, and ATP-bound states. The apo structure reveals an unexpected and previously uncharacterized assembly mode for ABC importers, where the lipoprotein DppA, a cluster C substrate-binding protein (SBP), stands upright on the translocator DppBCD primarily through its hinge region and N-lobe. These structural data, along with biochemical studies, reveal the assembly of DppABCD complex and the detailed mechanism of DppABCD-mediated transport. Together, these findings provide a molecular roadmap for understanding the transport mechanism of a cluster C SBP and its translocator.
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Affiliation(s)
- Tianyu Hu
- Shanghai Institute for Advanced Immunochemical Studies and School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Xiaolin Yang
- National Clinical Research Center for Infectious Disease, Shenzhen Third People's Hospital, Shenzhen 518112, China
| | - Yuanchen Zhu
- Shanghai Institute for Advanced Immunochemical Studies and School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Fengjiang Liu
- Innovative Center for Pathogen Research, Guangzhou Laboratory, Guangzhou 510005, China
| | - Xiuna Yang
- Shanghai Institute for Advanced Immunochemical Studies and School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
- Shanghai Clinical Research and Trial Center, Shanghai 201210, China
| | - Zhiqi Xiong
- Laboratory of Structural Biology, Tsinghua University, Beijing 100084, China
| | - Jingxi Liang
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300353, China
| | - Zhenli Lin
- Shanghai Institute for Advanced Immunochemical Studies and School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Yuting Ran
- Shanghai Institute for Advanced Immunochemical Studies and School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Luke W. Guddat
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Zihe Rao
- Shanghai Institute for Advanced Immunochemical Studies and School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
- National Clinical Research Center for Infectious Disease, Shenzhen Third People's Hospital, Shenzhen 518112, China
- Innovative Center for Pathogen Research, Guangzhou Laboratory, Guangzhou 510005, China
- Laboratory of Structural Biology, Tsinghua University, Beijing 100084, China
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300353, China
| | - Bing Zhang
- Shanghai Institute for Advanced Immunochemical Studies and School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
- Shanghai Clinical Research and Trial Center, Shanghai 201210, China
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Kaur K, Sharma S, Abhishek S, Kaur P, Saini UC, Dhillon MS, Karakousis PC, Verma I. Metabolic switching and cell wall remodelling of Mycobacterium tuberculosis during bone tuberculosis. J Infect 2023; 86:134-146. [PMID: 36549425 DOI: 10.1016/j.jinf.2022.12.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 12/12/2022] [Accepted: 12/13/2022] [Indexed: 12/24/2022]
Abstract
OBJECTIVES Bone tuberculosis (TB) is the third most common types of extrapulmonary tuberculosis. It is critical to understand mycobacterial adaptive strategies within bone lesions to identify mycobacterial factors that may have role in disease pathogenesis. METHODS Whole genome microarray was used to characterize the in-vivo transcriptome of Mycobacterium tuberculosis (M.tb) within bone TB specimens. Mycobacterial virulent proteins were identified by bioinformatic software. An in vitro osteoblast cell line model was used to study the role of these proteins in bone TB pathogenesis. RESULTS 914 mycobacterial genes were significantly overexpressed and 1688 were repressed in bone TB specimens. Pathway analysis of differentially expressed genes demonstrated a non-replicative and hypometabolic state of M.tb, reinforcement of the mycobacterial cell wall and induction of DNA damage repair responses, suggesting possible survival strategies of M.tb within bone. Bioinformatics mining of microarray data led to identification of five virulence proteins. The genes encoding these proteins were also upregulated in the in vitro MC3T3 osteoblast cell line model of bone TB. Further, exposure of osteoblast cells to two of these virulence proteins (Rv1046c and Rv3663c) significantly inhibited osteoblast differentiation. CONCLUSION M.tb alters its transcriptome to establish infection in bone by upregulating certain virulence genes which play a key role in disturbing bone homeostasis.
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Affiliation(s)
- Khushpreet Kaur
- Department of Biochemistry, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Sumedha Sharma
- Department of Biochemistry, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Sudhanshu Abhishek
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Prabhdeep Kaur
- Department of Biochemistry, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Uttam Chand Saini
- Department of Orthopaedics, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Mandeep Singh Dhillon
- Department of Orthopaedics, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Petros C Karakousis
- Centers for Tuberculosis Research and Systems Approaches for Infectious Diseases, School of Medicine, Johns Hopkins University, Baltimore, MD, United States
| | - Indu Verma
- Department of Biochemistry, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
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Li Q, Peng Z, Fu X, Wang H, Zhao Z, Pang Y, Chen L. Rv3737 is required for Mycobacterium tuberculosis growth in vitro and in vivo and correlates with bacterial load and disease severity in human tuberculosis. BMC Infect Dis 2022; 22:256. [PMID: 35287590 PMCID: PMC8919692 DOI: 10.1186/s12879-021-06967-y] [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: 02/20/2021] [Accepted: 12/07/2021] [Indexed: 11/13/2022] Open
Abstract
Background Rv3737 is the sole homologue of multifunctional transporter ThrE in Mycobacterium tuberculosis (Mtb). In this study, we aimed to investigate whether this transporter participates in vitro and in vivo survival of Mtb. Methods To characterize the role of Rv3737, we constructed and characterized a Mtb H37RvΔRv3737. This strain was evaluated for altered growth rate and macrophage survival using a cell model of infection. In addition, the comparative analysis was conducted to determine the association between Rv3737 mRNA expression and disease severity in active pulmonary TB patients. Results The H37RvΔRv3737 strain exhibited significantly slow growth rate compared to H37Rv-WT strain in standard culture medium. Additionally, the survival rate of H37Rv-WT strain in macrophages was 2 folds higher than that of H37RvΔRv3737 at 72 h. A significantly higher level of TNF-α and IL-6 mRNA expression was observed in macrophages infected with H37RvΔRv3737 as compared to H37Rv-WT. Of note, Rv3737 expression was significantly increased in clinical Mtb isolates than H37Rv-WT. The relative expression level of Rv3737 was positively correlated with lung cavity number of TB patients. Similarly, the higher Rv3737 mRNA level resulted in lower C(t) value by Xpert MTB/RIF assay, demonstrating that a positive correlation between Rv3737 expression and bacterial load in TB patients. Conclusions Our data takes the lead in demonstrate that the threonine transporter Rv3737 is required for in vitro growth and survival of bacteria inside macrophages. In addition, the expression level of Rv3737 may be associated with bacterial load and disease severity in pulmonary tuberculosis patients. Supplementary Information The online version contains supplementary material available at 10.1186/s12879-021-06967-y.
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Affiliation(s)
- Qing Li
- Tuberculosis Division of Respiratory and Critical Care Medicine, Affiliated Hospital of Zunyi Medical University, No. 149, Dalian Road, Huichuan District, Zunyi City, 563000, Guizhou Province, China.,Department of Bacteriology and Immunology, Beijing Key Laboratory for Drug Resistant Tuberculosis Research, Beijing Chest Hospital, Capital Medical University, Beijing Tuberculosis and Thoracic Tumor Institute, Area 2, Yard 9, Beiguan Street, Yongzhun Town, Tongzhou District, Beijing, 101100, China
| | - Zhangli Peng
- Tuberculosis Division of Respiratory and Critical Care Medicine, Affiliated Hospital of Zunyi Medical University, No. 149, Dalian Road, Huichuan District, Zunyi City, 563000, Guizhou Province, China
| | - Xuefeng Fu
- Tuberculosis Division of Respiratory and Critical Care Medicine, Affiliated Hospital of Zunyi Medical University, No. 149, Dalian Road, Huichuan District, Zunyi City, 563000, Guizhou Province, China
| | - Hong Wang
- Tuberculosis Division of Respiratory and Critical Care Medicine, Affiliated Hospital of Zunyi Medical University, No. 149, Dalian Road, Huichuan District, Zunyi City, 563000, Guizhou Province, China
| | - Zhaoliang Zhao
- Tuberculosis Division of Respiratory and Critical Care Medicine, Affiliated Hospital of Zunyi Medical University, No. 149, Dalian Road, Huichuan District, Zunyi City, 563000, Guizhou Province, China
| | - Yu Pang
- Department of Bacteriology and Immunology, Beijing Key Laboratory for Drug Resistant Tuberculosis Research, Beijing Chest Hospital, Capital Medical University, Beijing Tuberculosis and Thoracic Tumor Institute, Area 2, Yard 9, Beiguan Street, Yongzhun Town, Tongzhou District, Beijing, 101100, China.
| | - Ling Chen
- Tuberculosis Division of Respiratory and Critical Care Medicine, Affiliated Hospital of Zunyi Medical University, No. 149, Dalian Road, Huichuan District, Zunyi City, 563000, Guizhou Province, China.
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Fernando DM, Gee CT, Griffith EC, Meyer CJ, Wilt LA, Tangallapally R, Wallace MJ, Miller DJ, Lee RE. Biophysical analysis of the Mycobacteria tuberculosis peptide binding protein DppA reveals a stringent peptide binding pocket. Tuberculosis (Edinb) 2022; 132:102157. [PMID: 34894561 PMCID: PMC8818035 DOI: 10.1016/j.tube.2021.102157] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Revised: 11/21/2021] [Accepted: 11/26/2021] [Indexed: 01/03/2023]
Abstract
The peptide binding protein DppA is an ABC transporter found in prokaryotes that has the potential to be used as drug delivery tool for hybrid antibiotic compounds. Understanding the motifs and structures that bind to DppA is critical to the development of these bivalent compounds. This study focused on the biophysical analysis of the MtDppA from M. tuberculosis. Analysis of the crystal structure revealed a SVA tripeptide was co-crystallized with the protein. Further peptide analysis demonstrated MtDppA shows very little affinity for dipeptides but rather preferentially binds to peptides that are 3-4 amino acids in length. The structure-activity relationships (SAR) between MtDppA and tripeptides with varied amino acid substitutions were evaluated using thermal shift, SPR, and molecular dynamics simulations. Efforts to identify novel ligands for use as alternative scaffolds through the thermal shift screening of 35,000 compounds against MtDppA were unsuccessful, indicating that the MtDppA binding pocket is highly specialized for uptake of peptides. Future development of compounds that seek to utilize MtDppA as a drug delivery mechanism, will likely require a tri- or tetrapeptide component with a hydrophobic -non-acidic peptide sequence.
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Affiliation(s)
- Dinesh M. Fernando
- Department of Chemical Biology and Therapeutics, St. Jude Children’s Research Hospital, Memphis, TN 38105
| | - Clifford T. Gee
- Department of Chemical Biology and Therapeutics, St. Jude Children’s Research Hospital, Memphis, TN 38105
| | - Elizabeth C. Griffith
- Department of Chemical Biology and Therapeutics, St. Jude Children’s Research Hospital, Memphis, TN 38105
| | - Christopher J. Meyer
- Department of Chemical Biology and Therapeutics, St. Jude Children’s Research Hospital, Memphis, TN 38105
| | - Laura A. Wilt
- Department of Chemical Biology and Therapeutics, St. Jude Children’s Research Hospital, Memphis, TN 38105
| | - Rajendra Tangallapally
- Department of Chemical Biology and Therapeutics, St. Jude Children’s Research Hospital, Memphis, TN 38105
| | - Miranda J. Wallace
- Department of Chemical Biology and Therapeutics, St. Jude Children’s Research Hospital, Memphis, TN 38105
| | - Darcie J. Miller
- Department of Structural Biology, St. Jude Children’s Research Hospital, Memphis, TN 38105
| | - Richard E. Lee
- Department of Chemical Biology and Therapeutics, St. Jude Children’s Research Hospital, Memphis, TN 38105,Corresponding Author:
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Fullam E, Young RJ. Physicochemical properties and Mycobacterium tuberculosis transporters: keys to efficacious antitubercular drugs? RSC Med Chem 2020; 12:43-56. [PMID: 34041481 PMCID: PMC8130550 DOI: 10.1039/d0md00265h] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 10/15/2020] [Indexed: 12/14/2022] Open
Abstract
Securing novel, safe, and effective medicines to treat Mycobacterium tuberculosis remains an elusive goal, particularly influenced by the largely impervious Mtb envelope that limits exposure and thus efficacy of inhibitors at their cellular and periplasmic targets. The impact of physicochemical properties on pharmacokinetic parameters that govern oral absorption and exposure at sites of infection is considered alongside how these properties influence penetration of the Mtb envelope, with the likely influence of transporter proteins. The findings are discussed to benchmark current drugs and the emerging pipeline, whilst considering tactics for future rational and targeted design strategies, based around emerging data on Mtb transporters and their structures and functions.
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Affiliation(s)
- Elizabeth Fullam
- School of Life Sciences, University of Warwick Coventry CV4 7AL UK
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Alipoor SD, Adcock IM, Tabarsi P, Folkerts G, Mortaz E. MiRNAs in tuberculosis: Their decisive role in the fate of TB. Eur J Pharmacol 2020; 886:173529. [PMID: 32919937 DOI: 10.1016/j.ejphar.2020.173529] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 08/28/2020] [Accepted: 08/28/2020] [Indexed: 12/20/2022]
Abstract
Tuberculosis (TB) is one of the most lethal global infectious diseases. Despite the availability of much higher levels of technology in health and medicine, tuberculosis still remains a serious global health problem. Mycobacterium tuberculosis has the capacity for prolonged survival inside macrophages by exploiting host metabolic and energy pathways and perturbing autophagy and apoptosis of infected cells. The mechanism(s) underlying this process are not completely understood but evidence suggests that mycobacteria subvert the host miRNA network to enable mycobacterial survival. We present here a comprehensive review on the role of miRNAs in TB immune escape mechanisms and the potential for miRNA-based TB therapeutics. Further validation studies are required to (i) elucidate the precise effect of TB on host miRNAs, (ii) determine the inhibition of mycobacterial burden using miRNA-based therapies and (iii) identify novel miRNA biomarkers that may prove useful in TB diagnosis and treatment monitoring.
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Affiliation(s)
- Shamila D Alipoor
- Department of Molecular Medicine, Institute of Medical Biotechnology, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran
| | - Ian M Adcock
- National Heart and Lung Institute, Imperial College London, London, United Kingdom; Priority Research Centre for Healthy Lungs, Hunter Medical Research Institute, The University of Newcastle, Newcastle, NSW, Australia
| | - Payam Tabarsi
- Clinical Tuberculosis and Epidemiology Research Center, National Research Institute of Tuberculosis and Lung Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Gert Folkerts
- Division of Pharmacology, Faculty of Science, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, Netherlands
| | - Esmaeil Mortaz
- Clinical Tuberculosis and Epidemiology Research Center, National Research Institute of Tuberculosis and Lung Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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Soni DK, Dubey SK, Bhatnagar R. ATP-binding cassette (ABC) import systems of Mycobacterium tuberculosis: target for drug and vaccine development. Emerg Microbes Infect 2020; 9:207-220. [PMID: 31985348 PMCID: PMC7034087 DOI: 10.1080/22221751.2020.1714488] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Nutrient procurement specifically from nutrient-limiting environment is essential for pathogenic bacteria to survive and/or persist within the host. Long-term survival or persistent infection is one of the main reasons for the overuse of antibiotics, and contributes to the development and spread of antibiotic resistance. Mycobacterium tuberculosis is known for long-term survival within the host, and develops multidrug resistance. Before and during infection, the pathogen encounters various harsh environmental conditions. To cope up with such nutrient-limiting conditions, it is crucial to uptake essential nutrients such as ions, sugars, amino acids, peptides, and metals, necessary for numerous vital biological activities. Among the various types of transporters, ATP-binding cassette (ABC) importers are essentially unique to bacteria, accessible as drug targets without penetrating the cytoplasmic membrane, and offer an ATP-dependent gateway into the cell by mimicking substrates of the importer and designing inhibitors against substrate-binding proteins, ABC importers endeavour for the development of successful drug candidates and antibiotics. Alternatively, the production of antibodies against substrate-binding proteins could lead to vaccine development. In this review, we will emphasize the role of M. tuberculosis ABC importers for survival and virulence within the host. Furthermore, we will elucidate their unique characteristics to discover emerging therapies to combat tuberculosis.
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Affiliation(s)
- Dharmendra Kumar Soni
- Molecular Biology and Genetic Engineering Laboratory, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
| | - Suresh Kumar Dubey
- Department of Botany, Institute of Science, Banaras Hindu University, Varanasi, India
| | - Rakesh Bhatnagar
- Molecular Biology and Genetic Engineering Laboratory, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
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Mitra A, Ko YH, Cingolani G, Niederweis M. Heme and hemoglobin utilization by Mycobacterium tuberculosis. Nat Commun 2019; 10:4260. [PMID: 31534126 PMCID: PMC6751184 DOI: 10.1038/s41467-019-12109-5] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 08/21/2019] [Indexed: 12/31/2022] Open
Abstract
Iron is essential for growth of Mycobacterium tuberculosis (Mtb), but most iron in the human body is stored in heme within hemoglobin. Here, we demonstrate that the substrate-binding protein DppA of the inner membrane Dpp transporter is required for heme and hemoglobin utilization by Mtb. The 1.27 Å crystal structure of DppA shows a tetrapeptide bound in the protein core and a large solvent-exposed crevice for heme binding. Mutation of arginine 179 in this cleft eliminates heme binding to DppA and prevents heme utilization by Mtb. The outer membrane proteins PPE36 and PPE62 are also required for heme and hemoglobin utilization, indicating that these pathways converge at the cell surface of Mtb. Albumin, the most abundant blood protein, binds heme specifically and bypasses the requirements for PPE36, PPE62 and Dpp. Thus, our study reveals albumin-dependent and -independent heme uptake pathways, highlighting the importance of iron acquisition from heme for Mtb.
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Affiliation(s)
- Avishek Mitra
- Department of Microbiology, University of Alabama at Birmingham, 845 19th Street South, Birmingham, AL, 35294, USA
| | - Ying-Hui Ko
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 233S. 10th Street, Philadelphia, PA, 19107, USA
| | - Gino Cingolani
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 233S. 10th Street, Philadelphia, PA, 19107, USA. .,Institute of Biomembranes and Bioenergetics, National Research Council, Via Amendola 165/A, 70126, Bari, Italy.
| | - Michael Niederweis
- Department of Microbiology, University of Alabama at Birmingham, 845 19th Street South, Birmingham, AL, 35294, USA.
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Abstract
Free-living bacteria can assemble into multicellular structures called biofilms. Biofilms help bacteria tolerate multiple stresses, including antibiotics and the host immune system. Nontuberculous mycobacteria are a group of emerging opportunistic pathogens that utilize biofilms to adhere to household plumbing and showerheads and to avoid phagocytosis by host immune cells. Typically, bacteria regulate biofilm formation by controlling expression of adhesive structures to attach to surfaces and other bacterial cells. Mycobacteria harbor a unique cell wall built chiefly of long-chain mycolic acids that confers hydrophobicity and has been thought to cause constitutive aggregation in liquid media. Here we show that aggregation is instead a regulated process dictated by the balance of available carbon and nitrogen. Understanding that mycobacteria utilize metabolic cues to regulate the transition between planktonic and aggregated cells reveals an inroad to controlling biofilm formation through targeted therapeutics. Nontuberculous mycobacteria (NTM) are emerging opportunistic pathogens that colonize household water systems and cause chronic lung infections in susceptible patients. The ability of NTM to form surface-attached biofilms in the nonhost environment and corded aggregates in vivo is important to their ability to persist in both contexts. Underlying the development of these multicellular structures is the capacity of mycobacterial cells to adhere to one another. Unlike most other bacteria, NTM spontaneously and constitutively aggregate in vitro, hindering our ability to understand the transition between planktonic and aggregated cells. While culturing a model NTM, Mycobacterium smegmatis, in rich medium, we fortuitously discovered that planktonic cells accumulate after ∼3 days of growth. By providing selective pressure for bacteria that disperse earlier, we isolated a strain with two mutations in the oligopeptide permease operon (opp). A mutant lacking the opp operon (Δopp) disperses earlier than wild type (WT) due to a defect in nutrient uptake. Experiments with WT M. smegmatis revealed that growth as aggregates is favored when carbon is replete, but under conditions of low available carbon relative to available nitrogen, M. smegmatis grows as planktonic cells. By adjusting carbon and nitrogen sources in defined medium, we tuned the cellular C/N ratio such that M. smegmatis grows either as aggregates or as planktonic cells. C/N-mediated aggregation regulation is widespread among NTM with the possible exception of rough-colony Mycobacterium abscessus isolates. Altogether, we show that NTM aggregation is a controlled process that is governed by the relative availability of carbon and nitrogen for metabolism.
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Zhu L, Shahid MA, Markham J, Browning GF, Noormohammadi AH, Marenda MS. Comparative genomic analyses of Mycoplasma synoviae vaccine strain MS-H and its wild-type parent strain 86079/7NS: implications for the identification of virulence factors and applications in diagnosis of M. synoviae. Avian Pathol 2019; 48:537-548. [PMID: 31244324 DOI: 10.1080/03079457.2019.1637514] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Mycoplasma synoviae is an economically important avian pathogen worldwide, causing respiratory disease, infectious synovitis, airsacculitis and eggshell apex abnormalities in commercial chickens. Despite the widespread use of MS-H as a live attenuated vaccine over the past two decades, the precise molecular basis for loss of virulence in this vaccine is not yet fully understood. To address this, the whole genome sequence of the vaccine parent strain, 86079/7NS, was obtained and compared to that of the MS-H vaccine. Except for the vlhA expressed region, both genomes were nearly identical. Thirty-two single nucleotide polymorphisms (SNPs) were identified in MS-H, including 11 non-synonymous mutations that were predicted, by bioinformatics analysis, to have changed the secondary structure of the deduced proteins. One of these mutations caused truncation of the oppF-1 gene, which encodes the ATP-binding protein of an oligopeptide permease transporter. Overall, the attenuation of MS-H strain may be caused by the cumulative and complex effects of several mutations. The SNPs identified in MS-H were further analyzed by comparing the MS-H and 86079/7NS sequences with the strains WVU-1853 and MS53. In the genomic regions conserved between all strains, 30 SNPs were found to be unique to MS-H lineage. These results have provided a foundation for developing novel biomarkers for the detection of virulence in M. synoviae and also for designing new genotyping assays for discrimination of MS-H from field strains.
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Affiliation(s)
- Ling Zhu
- Asia-Pacific Centre for Animal Health, Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, the University of Melbourne , Werribee , Australia
| | - Muhammad A Shahid
- Department of Pathobiology, Faculty of Veterinary Sciences, Bahauddin Zakariya University , Multan , Pakistan
| | - John Markham
- Department of Electrical and Electronic Engineering, the University of Melbourne , Parkville , Australia
| | - Glenn F Browning
- Asia-Pacific Centre for Animal Health, Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, the University of Melbourne , Parkville , Australia
| | - Amir H Noormohammadi
- Asia-Pacific Centre for Animal Health, Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, the University of Melbourne , Werribee , Australia
| | - Marc S Marenda
- Asia-Pacific Centre for Animal Health, Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, the University of Melbourne , Werribee , Australia
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Song N, Li Z, Cui Z, Chen L, Cui Y, Dang G, Li Z, Li H, Liu S. The prominent alteration in transcriptome and metabolome of Mycobacterium bovis BCG str. Tokyo 172 induced by vitamin B 1. BMC Microbiol 2019; 19:104. [PMID: 31117936 PMCID: PMC6530141 DOI: 10.1186/s12866-019-1492-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 05/14/2019] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Vitamin B1 (VB1) is a crucial dietary nutrient and essential cofactor for several key enzymes in the regulation of cellular and metabolic processes, and more importantly in the activation of immune system. To date, the precise role of VB1 in Mycobacterium tuberculosis remains to be fully understood. RESULTS In this study, the transcriptional and metabolic profiles of VB1-treated Mycobacterium. bovis BCG were analyzed by RNA-sequencing and LC-MS (Liquid chromatography coupled to mass spectrometry). The selection of BCG strain was based on its common physiological features shared with M. tuberculosis. The results of cell growth assays demonstrated that VB1 inhibited the BCG growth rate in vitro. Transcriptomic analysis revealed that the expression levels of genes related to fatty acid metabolism, cholesterol metabolism, glycolipid catabolism, DNA replication, protein translation, cell division and cell wall formation were significantly downregulated in M. bovis BCG treated with VB1. In addition, the metabolomics LC-MS data indicated that most of the amino acids and adenosine diphosphate (ADP) were decreased in M. bovis BCG strain after VB1 treatment. CONCLUSIONS This study provides the molecular and metabolic bases to understand the impacts of VB1 on M.bovis BCG.
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Affiliation(s)
- Ningning Song
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Zhaoli Li
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Ziyin Cui
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Liping Chen
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Yingying Cui
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Guanghui Dang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Zhe Li
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - He Li
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Siguo Liu
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
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12
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Hünnefeld M, Persicke M, Kalinowski J, Frunzke J. The MarR-Type Regulator MalR Is Involved in Stress-Responsive Cell Envelope Remodeling in Corynebacterium glutamicum. Front Microbiol 2019; 10:1039. [PMID: 31164873 PMCID: PMC6536590 DOI: 10.3389/fmicb.2019.01039] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 04/25/2019] [Indexed: 12/03/2022] Open
Abstract
It is the enormous adaptive capacity of microorganisms, which is key to their competitive success in nature, but also challenges antibiotic treatment of human diseases. To deal with a diverse set of stresses, bacteria are able to reprogram gene expression using a wide variety of transcription factors. Here, we focused on the MarR-type regulator MalR conserved in the Corynebacterineae, including the prominent pathogens Corynebacterium diphtheriae and Mycobacterium tuberculosis. In several corynebacterial species, the malR gene forms an operon with a gene encoding a universal stress protein (uspA). Chromatin affinity purification and sequencing (ChAP-Seq) analysis revealed that MalR binds more than 60 target promoters in the C. glutamicum genome as well as in the large cryptic prophage CGP3. Overproduction of MalR caused severe growth defects and an elongated cell morphology. ChAP-Seq data combined with a global transcriptome analysis of the malR overexpression strain emphasized a central role of MalR in cell envelope remodeling in response to environmental stresses. For example, prominent MalR targets are involved in peptidoglycan biosynthesis and synthesis of branched-chain fatty acids. Phenotypic microarrays suggested an altered sensitivity of a ΔmalR mutant toward several β-lactam antibiotics. Furthermore, we revealed MalR as a repressor of several prophage genes, suggesting that MalR may be involved in the control of stress-responsive induction of the large CGP3 element. In conclusion, our results emphasize MalR as a regulator involved in stress-responsive remodeling of the cell envelope of C. glutamicum and suggest a link between cell envelope stress and the control of phage gene expression.
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Affiliation(s)
- Max Hünnefeld
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich, Jülich, Germany
| | - Marcus Persicke
- Center for Biotechnology, Bielefeld University, Bielefeld, Germany
| | - Jörn Kalinowski
- Center for Biotechnology, Bielefeld University, Bielefeld, Germany
| | - Julia Frunzke
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich, Jülich, Germany
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13
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Xu Z, Zhou A, Wu J, Zhou A, Li J, Zhang S, Wu W, Karakousis PC, Yao YF. Transcriptional Approach for Decoding the Mechanism of rpoC Compensatory Mutations for the Fitness Cost in Rifampicin-Resistant Mycobacterium tuberculosis. Front Microbiol 2018; 9:2895. [PMID: 30555440 PMCID: PMC6283890 DOI: 10.3389/fmicb.2018.02895] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2018] [Accepted: 11/12/2018] [Indexed: 12/31/2022] Open
Abstract
Multidrug-resistant tuberculosis (TB), defined as TB resistant to the two first-line drugs, isoniazid and rifampin, is a serious challenge to global TB eradication efforts. Although mutations in rpoA or rpoC have been proposed to compensate for this fitness cost due to rpoB mutation in rifampicin-resistant Mycobacterium tuberculosis mutants, whether the compensatory effect exists and the underlying mechanisms of compensation remain unclear. Here, we used RNA sequencing to investigate the global transcriptional profiles of 6 rifampin-resistant clinical isolates with either single mutation in rpoB or dual mutations in rpoB/rpoC, as well as 3 rifampin-susceptible clinical isolates, trying to prove the potential compensatory effect of rpoC by transcriptomic alteration. In rifampin-free conditions, rpoC mutation was associated with M. tuberculosis upregulation of ribosomal protein-coding genes, dysregulation of growth-related essential genes and balancing the expression of arginine and glutamate synthesis-associated genes. Upon rifampin exposure of M. tuberculosis isolates, rpoC mutations were associated with the upregulation of the oxidative phosphorylation machinery, which was inhibited in the rpoB single mutants, as well as stabilization of the expression of rifampin-regulated essential genes and balancing the expression of genes involved in metabolism of sulfur-containing amino acids. Taken together, our data suggest that rpoC mutation may compensate for the fitness defect of rifampicin-resistant M. tuberculosis by altering gene expression in response to rifampin exposure.
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Affiliation(s)
- Zhihong Xu
- Laboratory of Bacterial Pathogenesis, Department of Microbiology and Immunology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Aiping Zhou
- Department of Laboratory Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Jiawei Wu
- Faculty of Basic Medicine, Key Laboratory of Cell Differentiation and Apoptosis of the Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Aiwu Zhou
- Faculty of Basic Medicine, Key Laboratory of Cell Differentiation and Apoptosis of the Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jun Li
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Shulin Zhang
- Laboratory of Bacterial Pathogenesis, Department of Microbiology and Immunology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Wenjuan Wu
- Department of Laboratory Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Petros C Karakousis
- Department of Medicine, Center for Tuberculosis Research, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Yu-Feng Yao
- Laboratory of Bacterial Pathogenesis, Department of Microbiology and Immunology, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Department of Laboratory Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
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14
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Tanaka KJ, Pinkett HW. Oligopeptide-binding protein from nontypeable Haemophilus influenzae has ligand-specific sites to accommodate peptides and heme in the binding pocket. J Biol Chem 2018; 294:1070-1082. [PMID: 30455346 DOI: 10.1074/jbc.ra118.004479] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 11/14/2018] [Indexed: 11/06/2022] Open
Abstract
In nontypeable Haemophilus influenzae (NTHi), the oligopeptide-binding protein (OppA) serves as the substrate-binding protein (SBP) of the oligopeptide transport system responsible for the import of peptides. We solved the crystal structure of nthiOppA in complex with hydrophobic peptides of various sizes. Our novel hexapeptide complex demonstrates the flexibility of the nthiOppA-binding cavity to expand and accommodate the longer peptide while maintaining similar protein-peptide interactions of smaller peptide complexes. In addition to acquiring peptides from the host environment, as a heme auxotroph NTHi utilizes host hemoproteins as a source of essential iron. OppA is a member of the Cluster C SBP family, and unlike other SBP families, some members recognize two distinctly different substrates. DppA (dipeptide), MppA (murein tripeptide), and SapA (antimicrobial peptides) are Cluster C proteins known to also transport heme. We observed nthiOppA shares this heme-binding characteristic and established heme specificity and affinity by surface plasmon resonance (SPR) of the four Cluster C proteins in NTHi. Ligand-docking studies predicted a distinct heme-specific cleft in the binding pocket, and using SPR competition assays, we observed that heme does not directly compete with peptide in the substrate-binding pocket. Additionally, we identified that the individual nthiOppA domains differentially contribute to substrate binding, with one domain playing a dominant role in heme binding and the other in peptide binding. Our results demonstrate the multisubstrate specificity of nthiOppA and the role of NTHi Cluster C proteins in the heme-uptake pathway for this pathogen.
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Affiliation(s)
- Kari J Tanaka
- From the Department of Molecular Biosciences, Northwestern University, Evanston, Illinois 60208
| | - Heather W Pinkett
- From the Department of Molecular Biosciences, Northwestern University, Evanston, Illinois 60208
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15
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Chancellor A, Tocheva AS, Cave-Ayland C, Tezera L, White A, Al Dulayymi JR, Bridgeman JS, Tews I, Wilson S, Lissin NM, Tebruegge M, Marshall B, Sharpe S, Elliott T, Skylaris CK, Essex JW, Baird MS, Gadola S, Elkington P, Mansour S. CD1b-restricted GEM T cell responses are modulated by Mycobacterium tuberculosis mycolic acid meromycolate chains. Proc Natl Acad Sci U S A 2017; 114:E10956-E10964. [PMID: 29158404 PMCID: PMC5754766 DOI: 10.1073/pnas.1708252114] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Tuberculosis (TB), caused by Mycobacterium tuberculosis, remains a major human pandemic. Germline-encoded mycolyl lipid-reactive (GEM) T cells are donor-unrestricted and recognize CD1b-presented mycobacterial mycolates. However, the molecular requirements governing mycolate antigenicity for the GEM T cell receptor (TCR) remain poorly understood. Here, we demonstrate CD1b expression in TB granulomas and reveal a central role for meromycolate chains in influencing GEM-TCR activity. Meromycolate fine structure influences T cell responses in TB-exposed individuals, and meromycolate alterations modulate functional responses by GEM-TCRs. Computational simulations suggest that meromycolate chain dynamics regulate mycolate head group movement, thereby modulating GEM-TCR activity. Our findings have significant implications for the design of future vaccines that target GEM T cells.
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Affiliation(s)
- Andrew Chancellor
- Academic Unit of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, United Kingdom
- Public Health England, National Infections Service, Porton Down, Salisbury SP4 0JQ, United Kingdom
| | - Anna S Tocheva
- Academic Unit of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, United Kingdom
| | - Chris Cave-Ayland
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Liku Tezera
- Academic Unit of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, United Kingdom
| | - Andrew White
- Public Health England, National Infections Service, Porton Down, Salisbury SP4 0JQ, United Kingdom
| | - Juma'a R Al Dulayymi
- School of Chemistry, Bangor University, Bangor, Gwynedd LL57 2UW, United Kingdom
| | | | - Ivo Tews
- School of Biological Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom
- Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Susan Wilson
- Academic Unit of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, United Kingdom
- Histochemistry Unit, University of Southampton, Southampton SO16 6YD, United Kingdom
| | | | - Marc Tebruegge
- Academic Unit of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, United Kingdom
- Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom
- NIHR Southampton Biomedical Research Centre, Southampton SO17 1BJ, United Kingdom
- Global Health Research Institute, University of Southampton, Southampton SO17 1BJ, United Kingdom
- Department of Paediatrics, Faculty of Medicine, University of Melbourne, 3052 Parkville, Australia
- Department of Paediatric Infectious Diseases & Immunology, Evelina London Children's Hospital, Guy's and St. Thomas' NHS Foundation Trust, London SE1 7EH, United Kingdom
| | - Ben Marshall
- Academic Unit of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, United Kingdom
- Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom
- NIHR Southampton Biomedical Research Centre, Southampton SO17 1BJ, United Kingdom
| | - Sally Sharpe
- Public Health England, National Infections Service, Porton Down, Salisbury SP4 0JQ, United Kingdom
| | - Tim Elliott
- Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom
- Cancer Sciences Unit, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, United Kingdom
| | - Chris-Kriton Skylaris
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
- Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Jonathan W Essex
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
- Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Mark S Baird
- School of Chemistry, Bangor University, Bangor, Gwynedd LL57 2UW, United Kingdom
| | - Stephan Gadola
- Academic Unit of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, United Kingdom
- Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom
- F. Hoffmann-La Roche Ltd., 4070 Basel, Switzerland
| | - Paul Elkington
- Academic Unit of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, United Kingdom
- Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom
- NIHR Southampton Biomedical Research Centre, Southampton SO17 1BJ, United Kingdom
- Global Health Research Institute, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Salah Mansour
- Academic Unit of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, United Kingdom;
- Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom
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16
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Hegde S, Zimmermann M, Flöck M, Brunthaler R, Spergser J, Rosengarten R, Chopra-Dewasthaly R. Genetic loci of Mycoplasma agalactiae involved in systemic spreading during experimental intramammary infection of sheep. Vet Res 2016; 47:106. [PMID: 27765069 PMCID: PMC5073455 DOI: 10.1186/s13567-016-0387-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 09/19/2016] [Indexed: 12/17/2022] Open
Abstract
Mycoplasmas are amongst the most successful pathogens of both humans and animals yet the molecular basis of mycoplasma pathogenesis is poorly understood. This is partly due to the lack of classical virulence factors and little similarity to common bacterial pathogenic determinants. Using Mycoplasma agalactiae as a model we initiated research in this direction by screening a transposon mutant library in the natural sheep host using a negative selection method. Having successfully identified putative factors involved in the colonization of local infection and lymphogenic sites, the current study assessed mutants unable to spread systemically in sheep after experimental intramammary infection. Analysis of distant body sites for complete absence of mutants via SSM PCR revealed that additional set of genes, such as pdhB, oppC, oppB, gtsB, MAG1890, MAG5520 and MAG3650 are required for systemic spreading apart from those that were necessary for initial colonization. Additional in vitro studies with the mutants absent at these systemic sites confirmed the potential role of some of the respective gene products concerning their interaction with host cells. Mutants of pdhB, oppC and MAG4460 exhibited significantly slower growth in the presence of HeLa cells in MEM medium. This first attempt to identify genes exclusively required for systemic spreading provides a basis for further in-depth research to understand the exact mechanism of chronicity and persistence of M. agalactiae.
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Affiliation(s)
- Shivanand Hegde
- Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210, Vienna, Austria.,Department of Pathology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Martina Zimmermann
- Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210, Vienna, Austria
| | - Martina Flöck
- Clinic for Ruminants, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210, Vienna, Austria
| | - Rene Brunthaler
- Institute of Pathology and Forensic Veterinary Medicine, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210, Vienna, Austria
| | - Joachim Spergser
- Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210, Vienna, Austria
| | - Renate Rosengarten
- Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210, Vienna, Austria
| | - Rohini Chopra-Dewasthaly
- Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210, Vienna, Austria.
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17
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Garai P, Chandra K, Chakravortty D. Bacterial peptide transporters: Messengers of nutrition to virulence. Virulence 2016; 8:297-309. [PMID: 27589415 DOI: 10.1080/21505594.2016.1221025] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Bacteria possess numerous peptide transporters for importing peptides as nutrients. However, these peptide transporters are now consistently reported to play a role in the virulence of various bacterial pathogens. Their ability to transport peptides has implications in antibacterial therapy as well. Therefore, it would be instrumental to have complete knowledge about the role of peptide transporters in mediating this cross connection between metabolism and pathogenesis. Studies on various peptide transporters in bacterial pathogens have improved our understanding of this field. In this review, we have given an overview of the functioning of bacterial peptide transporters and their contribution in virulence of major bacterial pathogens.
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Affiliation(s)
- Preeti Garai
- a Department of Microbiology and Cell Biology , Indian Institute of Science , Bangalore , India
| | - Kasturi Chandra
- a Department of Microbiology and Cell Biology , Indian Institute of Science , Bangalore , India
| | - Dipshikha Chakravortty
- a Department of Microbiology and Cell Biology , Indian Institute of Science , Bangalore , India
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18
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Mycobacteriophage putative GTPase-activating protein can potentiate antibiotics. Appl Microbiol Biotechnol 2016; 100:8169-77. [PMID: 27345061 DOI: 10.1007/s00253-016-7681-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 06/09/2016] [Accepted: 06/13/2016] [Indexed: 02/07/2023]
Abstract
The soaring incidences of infection by antimicrobial resistant (AR) pathogens and shortage of effective antibiotics with new mechanisms of action have renewed interest in phage therapy. This scenario is exemplified by resistant tuberculosis (TB), caused by resistant Mycobacterium tuberculosis. Mycobacteriophage SWU1 A321_gp67 encodes a putative GTPase-activating protein. Mycobacterium smegmatis with gp67 overexpression showed changed colony formation and biofilm morphology and supports the efficacy of streptomycin and capreomycin against Mycobacterium. gp67 down-regulated the transcription of genes involved in cell wall and biofilm development. To our knowledge, this is the first report to show that phage protein in addition to lysin or recombination components can synergize with existing antibiotics. Phage components might represent a promising new clue for better antibiotic potentiators.
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19
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Pandey R, Russo R, Ghanny S, Huang X, Helmann J, Rodriguez GM. MntR(Rv2788): a transcriptional regulator that controls manganese homeostasis in Mycobacterium tuberculosis. Mol Microbiol 2015; 98:1168-83. [PMID: 26337157 DOI: 10.1111/mmi.13207] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/27/2015] [Indexed: 12/23/2022]
Abstract
The pathogenic mycobacterium Mycobacterium tuberculosis encodes two members of the DtxR/MntR family of metalloregulators, IdeR and SirR. IdeR represses gene expression in response to ferrous iron, and we here demonstrate that SirR (Rv2788), although also annotated as an iron-dependent repressor, functions instead as a manganese-dependent transcriptional repressor and is therefore renamed MntR. MntR regulates transporters that promote manganese import and genes that respond to metal ion deficiency such as the esx3 system. Repression of manganese import by MntR is essential for survival of M. tuberculosis under conditions of high manganese availability, but mntR is dispensable during infection. In contrast, manganese import by MntH and MntABCD was found to be indispensable for replication of M. tuberculosis in macrophages. These results suggest that manganese is limiting in the host and that interfering with import of this essential metal may be an effective strategy to attenuate M. tuberculosis.
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Affiliation(s)
- Ruchi Pandey
- Public Health Research Institute at New Jersey Medical School, Rutgers State University of New Jersey, 225 Warren Street, Newark, NJ, 07103, USA
| | - Riccardo Russo
- New Jersey Medical School, Rutgers State University of New Jersey, 185 South Orange Avenue, Newark, NJ, 07103, USA
| | - Saleena Ghanny
- Genomics Research Program, NJMS, Rutgers State University of New Jersey, 185 South Orange Avenue, Newark, NJ, USA
| | - Xiaojuan Huang
- Department of Microbiology, Cornell University, Ithaca, NY, 14853-8101, USA
| | - John Helmann
- Department of Microbiology, Cornell University, Ithaca, NY, 14853-8101, USA
| | - G Marcela Rodriguez
- Public Health Research Institute at New Jersey Medical School, Rutgers State University of New Jersey, 225 Warren Street, Newark, NJ, 07103, USA
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20
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Decreasing global transcript levels over time suggest that phytoplasma cells enter stationary phase during plant and insect colonization. Appl Environ Microbiol 2015; 81:2591-602. [PMID: 25636844 DOI: 10.1128/aem.03096-14] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To highlight different transcriptional behaviors of the phytoplasma in the plant and animal host, expression of 14 genes of "Candidatus Phytoplasma asteris," chrysanthemum yellows strain, was investigated at different times following the infection of a plant host (Arabidopsis thaliana) and two insect vector species (Macrosteles quadripunctulatus and Euscelidius variegatus). Target genes were selected among those encoding antigenic membrane proteins, membrane transporters, secreted proteins, and general enzymes. Transcripts were detected for all analyzed genes in the three hosts; in particular, those encoding the antigenic membrane protein Amp, elements of the mechanosensitive channel, and two of the four secreted proteins (SAP54 and TENGU) were highly accumulated, suggesting that they play important roles in phytoplasma physiology during the infection cycle. Most transcripts were present at higher abundance in the plant host than in the insect hosts. Generally, transcript levels of the selected genes decreased significantly during infection of A. thaliana and M. quadripunctulatus but were more constant in E. variegatus. Such decreases may be explained by the fact that only a fraction of the phytoplasma population was transcribing, while the remaining part was aging to a stationary phase. This strategy might improve long-term survival, thereby increasing the likelihood that the pathogen may be acquired by a vector and/or inoculated to a healthy plant.
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21
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Ron M, Gorelick-Ashkenazi A, Levisohn S, Nir-Paz R, Geary SJ, Tulman E, Lysnyansky I, Yogev D. Mycoplasma gallisepticum in vivo induced antigens expressed during infection in chickens. Vet Microbiol 2014; 175:265-74. [PMID: 25575879 DOI: 10.1016/j.vetmic.2014.12.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 12/10/2014] [Accepted: 12/11/2014] [Indexed: 11/17/2022]
Abstract
Until now only a few genes encoding virulence factors have been characterized in the avian pathogen Mycoplasma gallisepticum. In order to identify candidate targets associated with infection we applied an immunoscreening technique-in vivo induced antigen technology (IVIAT)-to detect immunogens of M. gallisepticum strain Rlow expressed preferentially during in vivo infection. We identified 13 in vivo-induced (IVI) proteins that correspond to different functional categories including: previously reported putative virulence factors (GapA, PlpA, Hlp3, VlhA 1.07 and VlhA 4.01), transport (PotE, MGA_0241 and 0654), translation (L2, L23, ValS), chaperone (GroEL) and a protein with unknown function (MGA_0042). To validate the in vivo antigenic reactivity, 10 IVI proteins were tested by Western blot analysis using serum samples collected from chickens experimentally (with strain Rlow) and naturally (outbreaks, N=3) infected with M. gallisepticum. All IVI proteins tested were immunogenic. To corroborate these results, we tested expression of IVI genes in chickens experimentally infected with M. gallisepticum Rlow, and in MRC-5 human lung fibroblasts cell culture by using relative real time reverse-transcription PCR (RT-PCR). With the exception of MGA_0338, all six genes tested (MGA_1199, 0042, 0654, 0712, 0928 and 0241) were upregulated at least at one time point during experimental infection (2-4 week post-infection). In contrast, the expression of seven out of eight IVI genes (MGA_1199, 0152, 0338, 0042, 0654, 0712, 0928) were downregulated in MRC-5 cell culture at both 2 and 4h PI; MGA_0241 was upregulated 2h PI. Our data suggest that the identified IVI antigens may have important roles in the pathogenesis of M. gallisepticum infection in vivo.
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Affiliation(s)
- Merav Ron
- Department of Molecular Genetics and Microbiology, The Hebrew University-Haddassah Medical School, Jerusalem 91120, Israel
| | - Anna Gorelick-Ashkenazi
- Department of Molecular Genetics and Microbiology, The Hebrew University-Haddassah Medical School, Jerusalem 91120, Israel
| | - Sharon Levisohn
- Mycoplasma Unit, Department of Avian and Aquatic Diseases, Kimron Veterinary Institute, Beit Dagan 50250, Israel
| | - Ran Nir-Paz
- Department of Clinical Microbiology and Infectious Diseases, Hadassah Hebrew University Medical Center, Ein Kerem, Jerusalem, Israel
| | - Steven J Geary
- Department of Pathobiology and Veterinary Science and the Center of Excellence for Vaccine Research, University of Connecticut, Storrs, CT, USA
| | - Edan Tulman
- Department of Pathobiology and Veterinary Science and the Center of Excellence for Vaccine Research, University of Connecticut, Storrs, CT, USA
| | - Inna Lysnyansky
- Mycoplasma Unit, Department of Avian and Aquatic Diseases, Kimron Veterinary Institute, Beit Dagan 50250, Israel.
| | - David Yogev
- Department of Molecular Genetics and Microbiology, The Hebrew University-Haddassah Medical School, Jerusalem 91120, Israel
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22
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Abstract
Several major pathogens, including Mycobacterium tuberculosis, parasitize host cells and exploit host-derived nutrients to sustain their own metabolism. Although the carbon sources that are used by M. tuberculosis have been extensively studied, the mechanisms by which mycobacteria capture and metabolize nitrogen, which is another essential constituent of biomolecules, have only recently been revisited. In this Progress article, we discuss central nitrogen metabolism in M. tuberculosis, the mechanisms that are used by this pathogen to obtain nitrogen from its host and the potential role of nitrogen capture and metabolism in virulence.
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23
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Danelishvili L, Stang B, Bermudez LE. Identification of Mycobacterium avium genes expressed during in vivo infection and the role of the oligopeptide transporter OppA in virulence. Microb Pathog 2014; 76:67-76. [PMID: 25245008 DOI: 10.1016/j.micpath.2014.09.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Revised: 09/16/2014] [Accepted: 09/18/2014] [Indexed: 12/24/2022]
Abstract
Mycobacterium avium causes disseminated disease in patients with AIDS and other immunosuppressive conditions and pulmonary infections in individuals with chronic lung diseases. Much still need to be learn about the mechanisms of M. avium pathogenesis. Using a mouse model of disseminated M. avium disease, we applied an in vivo expression technology system and identified M. avium genes up-regulated in different organs of mice during early stage of infection. The M. avium oppA gene, involved in an active transport of oligopeptides across the cell membrane, was found highly expressed in lung, liver and spleen of mice. Mutation in the transport domain of the oppA gene resulted in bacterial attenuation in both macrophages and in mice. Using protein-protein interaction assay, it was determined that two hypothetical small proteins, MAV_2941 (73aa) and MAV_4320 (45aa), interact with OppA. MAV_2941 was shown to be secreted by the bacterium into the macrophage cytoplasm. Mutations in MAV_2941 was associated with significant impairment of growth in macrophages. Understanding the mechanisms involved in the functions of MAV_2941 and MAV_4320 is warranted.
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Affiliation(s)
- Lia Danelishvili
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331, USA
| | - Bernadette Stang
- Department of Clinical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331, USA
| | - Luiz E Bermudez
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331, USA; Department of Clinical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331, USA; Department of Microbiology, College of Science, Oregon State University, Corvallis, OR 97331, USA; Molecular and Cell Biology Program, College of Science, Oregon State University, Corvallis, OR 97331, USA.
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Küberl A, Fränzel B, Eggeling L, Polen T, Wolters DA, Bott M. Pupylated proteins in Corynebacterium glutamicum revealed by MudPIT analysis. Proteomics 2014; 14:1531-42. [PMID: 24737727 DOI: 10.1002/pmic.201300531] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Revised: 03/23/2014] [Accepted: 04/07/2014] [Indexed: 12/31/2022]
Abstract
In a manner similar to ubiquitin, the prokaryotic ubiquitin-like protein (Pup) has been shown to target proteins for degradation via the proteasome in mycobacteria. However, not all actinobacteria possessing the Pup protein also contain a proteasome. In this study, we set out to study pupylation in the proteasome-lacking non-pathogenic model organism Corynebacterium glutamicum. A defined pup deletion mutant of C. glutamicum ATCC 13032 grew aerobically as the parent strain in standard glucose minimal medium, indicating that pupylation is dispensable under these conditions. After expression of a Pup derivative carrying an aminoterminal polyhistidine tag in the Δpup mutant and Ni(2+)-chelate affinity chromatography, pupylated proteins were isolated. Multidimensional protein identification technology (MudPIT) and MALDI-TOF-MS/MS of the elution fraction unraveled 55 proteins being pupylated in C. glutamicum and 66 pupylation sites. Similar to mycobacteria, the majority of pupylated proteins are involved in metabolism or translation. Our results define the first pupylome of an actinobacterial species lacking a proteasome, confirming that other fates besides proteasomal degradation are possible for pupylated proteins.
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Affiliation(s)
- Andreas Küberl
- IBG-1: Biotechnology, Institute of Bio- and Geosciences, Forschungszentrum Jülich, Jülich, Germany
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25
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Characterization of the Opp peptide transporter of Corynebacterium pseudotuberculosis and its role in virulence and pathogenicity. BIOMED RESEARCH INTERNATIONAL 2014; 2014:489782. [PMID: 24895581 PMCID: PMC4034477 DOI: 10.1155/2014/489782] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Accepted: 04/16/2014] [Indexed: 11/17/2022]
Abstract
Despite the economic importance of caseous lymphadenitis (CLA), a chronic disease caused by Corynebacterium pseudotuberculosis, few genes related to the virulence of its etiologic agent have been characterized. The oligopeptide permease (Opp) transporters are located in the plasma membrane and have functions generally related to the uptake of peptides from the extracellular environment. These peptide transporters, in addition to having an important role in cell nutrition, also participate in the regulation of various processes involving intercellular signaling, including the control of the expression of virulence genes in pathogenic bacteria. To study the role of Opp in C. pseudotuberculosis, an OppD deficient strain was constructed via simple crossover with a nonreplicative plasmid carrying part of the oppD gene sequence. As occurred to the wild-type, the ΔoppD strain showed impaired growth when exposed to the toxic glutathione peptide (GSH), indicating two possible scenarios: (i) that this component can be internalized by the bacterium through an Opp-independent pathway or (ii) that there is toxicity while the peptide is extracellular. Additionally, the ΔoppD mutant presented a reduced ability to adhere to and infect macrophages compared to the wild-type, although both strains exhibit the same potential to colonize spleens and cause injury and death to infected mice.
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26
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Liu B, Zhang X, Huang H, Zhang Y, Zhou F, Wang G. A novel molecular typing method of Mycobacteria based on DNA barcoding visualization. J Clin Bioinforma 2014; 4:4. [PMID: 24555538 PMCID: PMC3931916 DOI: 10.1186/2043-9113-4-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Accepted: 02/10/2014] [Indexed: 11/10/2022] Open
Abstract
Different subtypes of Mycobacterium tuberculosis (MTB) may induce diverse severe human infections, and some of their symptoms are similar to other pathogenes, e.g. Nontuberculosis mycobacteria (NTM). So determination of mycobacterium subtypes facilitates the effective control of MTB infection and proliferation. This study exploits a novel DNA barcoding visualization method for molecular typing of 17 mycobacteria genomes published in the NCBI prokaryotic genome database. Three mycobacterium genes (Rv0279c, Rv3508 and Rv3514) from the PE/PPE family of MT Band were detected to best represent the inter-strain pathogenetic variations. An accurate and fast MTB substrain typing method was proposed based on the combination of the aforementioned three biomarker genes and the 16S rRNA gene. The protocol of establishing a bacterial substrain typing system used in this study may also be applied to the other pathogenes.
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Affiliation(s)
| | | | | | | | - Fengfeng Zhou
- Department of Pathogenobiology, Basic Medical College of Jilin University, Changchun, Jilin, China.
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27
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Teramoto K, Tamura T, Hanada S, Sato T, Kawasaki H, Suzuki KI, Sato H. Simple and rapid characterization of mycolic acids from Dietzia strains by using MALDI spiral-TOFMS with ultra high mass-resolving power. J Antibiot (Tokyo) 2013; 66:713-7. [PMID: 23981960 DOI: 10.1038/ja.2013.79] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 05/30/2013] [Accepted: 07/11/2013] [Indexed: 11/09/2022]
Abstract
Mycolic acids have been used as important chemotaxonomic markers. In this study, a newly developed matrix-assisted laser desorption/ionization time-of-flight mass spectrometer with a spiral ion trajectory (MALDI spiral-TOFMS) was applied to the characterization of mycolic acids of three type strains of validated species belonging to the genus Dietzia (D. papillomatosis 105045(T), D. kunjamensis NBRC 105042(T) and D. timorensis NBRC 104184(T)), by analysis of total fatty acid methyl ester fractions. In addition, owing to the high mass-resolving power of MALDI spiral-TOFMS, adjacent peaks (0.036 Da mass differences) were successfully separated, and weak peaks corresponding to oxygenated mycolic acids were detected. For all samples, the distributions of carbon-chain lengths were mainly in the range of C30-C42 and the average number of carbon-chain lengths was about 37, which agreed reasonably well with reported results for the genus Dietzia. The number of double bonds and/or cyclopropane rings was 0-2. Relative peak intensities of each mycolic acid methyl ester were used to compare the mycolic acids of the three strains. The mycolic acids of D. papillomatosis and D. kunjamensis were characterized by a high content of mycolic acids with 0-1 double bond or cyclopropane ring and an almost equal content of mycolic acids with odd- and even-numbered carbon-chain lengths. In contrast, mycolic acids of D. timorensis were characterized by a high content of mycolic acids with 1-2 double bonds and/or cyclopropane rings with an even-numbered carbon-chain length. By using MALDI spiral-TOFMS, mycolic acids from three type strains of the genus Dietzia were characterized easily and rapidly.
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Affiliation(s)
- Kanae Teramoto
- Advanced Technology Department, JEOL Ltd., Akishima, Japan
| | - Tomohiko Tamura
- Resource Collection Division, NITE Biological Resource Center Department of Biotechnology, Kisarazu, Japan
| | - Satoshi Hanada
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
| | | | - Hiroko Kawasaki
- Resource Collection Division, NITE Biological Resource Center Department of Biotechnology, Kisarazu, Japan
| | - Ken-ichiro Suzuki
- Resource Collection Division, NITE Biological Resource Center Department of Biotechnology, Kisarazu, Japan
| | - Hiroaki Sato
- Research Institute for Environmental Management Technology, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
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28
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Meehan CJ, Beiko RG. Lateral gene transfer of an ABC transporter complex between major constituents of the human gut microbiome. BMC Microbiol 2012; 12:248. [PMID: 23116195 PMCID: PMC3534369 DOI: 10.1186/1471-2180-12-248] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 10/24/2012] [Indexed: 12/30/2022] Open
Abstract
Background Several links have been established between the human gut microbiome and conditions such as obesity and inflammatory bowel syndrome. This highlights the importance of understanding what properties of the gut microbiome can affect the health of the human host. Studies have been undertaken to determine the species composition of this microbiome and infer functional profiles associated with such host properties. However, lateral gene transfer (LGT) between community members may result in misleading taxonomic attributions for the recipient organisms, thus making species-function links difficult to establish. Results We identified a peptides/nickel transport complex whose components differed in abundance based upon levels of host obesity, and assigned the encoded proteins to members of the microbial community. Each protein was assigned to several distinct taxonomic groups, with moderate levels of agreement observed among different proteins in the complex. Phylogenetic trees of these proteins produced clusters that differed greatly from taxonomic attributions and indicated that habitat-directed LGT of this complex is likely to have occurred, though not always between the same partners. Conclusions These findings demonstrate that certain membrane transport systems may be an important factor within an obese-associated gut microbiome and that such complexes may be acquired several times by different strains of the same species. Additionally, an example of individual proteins from different organisms being transferred into one operon was observed, potentially demonstrating a functional complex despite the donors of the subunits being taxonomically disparate. Our results also highlight the potential impact of habitat-directed LGT on the resident microbiota.
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Affiliation(s)
- Conor J Meehan
- Faculty of Computer Science, 6050 University Avenue, Halifax, NS B3H 1W5, Canada
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29
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Forrellad MA, Klepp LI, Gioffré A, Sabio y García J, Morbidoni HR, de la Paz Santangelo M, Cataldi AA, Bigi F. Virulence factors of the Mycobacterium tuberculosis complex. Virulence 2012; 4:3-66. [PMID: 23076359 PMCID: PMC3544749 DOI: 10.4161/viru.22329] [Citation(s) in RCA: 368] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The Mycobacterium tuberculosis complex (MTBC) consists of closely related species that cause tuberculosis in both humans and animals. This illness, still today, remains to be one of the leading causes of morbidity and mortality throughout the world. The mycobacteria enter the host by air, and, once in the lungs, are phagocytated by macrophages. This may lead to the rapid elimination of the bacillus or to the triggering of an active tuberculosis infection. A large number of different virulence factors have evolved in MTBC members as a response to the host immune reaction. The aim of this review is to describe the bacterial genes/proteins that are essential for the virulence of MTBC species, and that have been demonstrated in an in vivo model of infection. Knowledge of MTBC virulence factors is essential for the development of new vaccines and drugs to help manage the disease toward an increasingly more tuberculosis-free world.
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30
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Kumar P, Arora K, Lloyd JR, Lee IY, Nair V, Fischer E, Boshoff HIM, Barry CE. Meropenem inhibits D,D-carboxypeptidase activity in Mycobacterium tuberculosis. Mol Microbiol 2012; 86:367-81. [PMID: 22906310 DOI: 10.1111/j.1365-2958.2012.08199.x] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/02/2012] [Indexed: 12/28/2022]
Abstract
Carbapenems such as meropenem are being investigated for their potential therapeutic utility against highly drug-resistant tuberculosis. These β-lactams target the transpeptidases that introduce interpeptide cross-links into bacterial peptidoglycan thereby controlling rigidity of the bacterial envelope. Treatment of Mycobacterium tuberculosis (Mtb) with the β-lactamase inhibitor clavulanate together with meropenem resulted in rapid, polar, cell lysis releasing cytoplasmic contents. In Mtb it has been previously demonstrated that 3-3 cross-linkages [involving two diaminopimelate (DAP) molecules] predominate over 4-3 cross-linkages (involving one DAP and one D-alanine) in stationary-phase cells. We purified and analysed peptidoglycan from Mtb and found that 3-3 cross-linkages predominate throughout all growth phases and the ratio of 4-3/3-3 linkages does not vary significantly under any growth condition. Meropenem treatment was accompanied by a dramatic accumulation of unlinked pentapeptide stems with no change in the tetrapeptide pools, suggesting that meropenem inhibits both a D,D-carboxypeptidase and an L,D-transpeptidase. We purified a candidate D,D-carboxypeptidase DacB2 and showed that meropenem indeed directly inhibits this enzyme by forming a stable adduct at the enzyme active site. These results suggest that the rapid lysis of meropenem-treated cells is the result of synergistically inhibiting the transpeptidases that introduce 3,3-cross-links while simultaneously limiting the pool of available substrates available for cross-linking.
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Affiliation(s)
- Pradeep Kumar
- Tuberculosis Research Section, National Institute of Allergy and Infectious Disease, NIH, Bethesda, MD 20892, USA
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31
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Verschoor JA, Baird MS, Grooten J. Towards understanding the functional diversity of cell wall mycolic acids of Mycobacterium tuberculosis. Prog Lipid Res 2012; 51:325-39. [PMID: 22659327 DOI: 10.1016/j.plipres.2012.05.002] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Revised: 03/05/2012] [Accepted: 05/23/2012] [Indexed: 01/08/2023]
Abstract
Mycolic acids constitute the waxy layer of the outer cell wall of Mycobacterium spp. and a few other genera. They are diverse in structure, providing a unique chromatographic foot-print for almost each of the more than 70 Mycobacterium species. Although mainly esterified to cell wall arabinogalactan, trehalose or glucose, some free mycolic acid is secreted during in vitro growth of Mycobacterium tuberculosis. In M. tuberculosis, α-, keto- and methoxy-mycolic acids are the main classes, each differing in their ability to attract neutrophils, induce foamy macrophages or adopt an antigenic structure for antibody recognition. Of interest is their particular relationship to cholesterol, discovered by their ability to attract cholesterol, to bind Amphotericin B or to be recognised by monoclonal antibodies that cross-react with cholesterol. The structural elements that determine this diverse functionality include the carboxylic acid in the mycolic motif, as well as the nature and stereochemistry of the two functional groups in the merochain. The functional diversity of mycolic acid classes implies that much information may be contained in the selective expression and secretion of mycolic acids to establish tuberculosis after infection of the host. Their cholesteroid nature may relate to how they utilize host cholesterol for their persistent survival.
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Affiliation(s)
- Jan A Verschoor
- Department Biochemistry, University of Pretoria, Pretoria 0002, South Africa.
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Abramovitch RB, Rohde KH, Hsu FF, Russell DG. aprABC: a Mycobacterium tuberculosis complex-specific locus that modulates pH-driven adaptation to the macrophage phagosome. Mol Microbiol 2011; 80:678-94. [PMID: 21401735 DOI: 10.1111/j.1365-2958.2011.07601.x] [Citation(s) in RCA: 136] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Following phagocytosis by macrophages, Mycobacterium tuberculosis (Mtb) senses the intracellular environment and remodels its gene expression for growth in the phagosome. We have identified an acid and phagosome regulated (aprABC) locus that is unique to the Mtb complex and whose gene expression is induced during growth in acidic environments in vitro and in macrophages. Using the aprA promoter, we generated a strain that exhibits high levels of inducible fluorescence in response to growth in acidic medium in vitro and in macrophages. aprABC expression is dependent on the two-component regulator phoPR, linking phoPR signalling to pH sensing. Deletion of the aprABC locus causes defects in gene expression that impact aggregation, intracellular growth, and the relative levels of storage and cell wall lipids. We propose a model where phoPR senses the acidic pH of the phagosome and induces aprABC expression to fine-tune processes unique for intracellular adaptation of Mtb complex bacteria.
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Affiliation(s)
- Robert B Abramovitch
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14583, USA
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33
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The impact of transcriptomics on the fight against tuberculosis: focus on biomarkers, BCG vaccination, and immunotherapy. Clin Dev Immunol 2010; 2011:192630. [PMID: 21197423 PMCID: PMC3010624 DOI: 10.1155/2011/192630] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2010] [Accepted: 11/16/2010] [Indexed: 11/18/2022]
Abstract
In 1882 Robert Koch identified Mycobacterium tuberculosis as the causative agent of tuberculosis (TB), a disease as ancient as humanity. Although there has been more than 125 years of scientific effort aimed at understanding the disease, serious problems in TB persist that contribute to the estimated 1/3 of the world population infected with this pathogen. Nonetheless, during the first decade of the 21st century, there were new advances in the fight against TB. The development of high-throughput technologies is one of the major contributors to this advance, because it allows for a global vision of the biological phenomenon. This paper analyzes how transcriptomics are supporting the translation of basic research into therapies by resolving three key issues in the fight against TB: (a) the discovery of biomarkers, (b) the explanation of the variability of protection conferred by BCG vaccination, and (c) the development of new immunotherapeutic strategies to treat TB.
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Dasgupta A, Sureka K, Mitra D, Saha B, Sanyal S, Das AK, Chakrabarti P, Jackson M, Gicquel B, Kundu M, Basu J. An oligopeptide transporter of Mycobacterium tuberculosis regulates cytokine release and apoptosis of infected macrophages. PLoS One 2010; 5:e12225. [PMID: 20808924 PMCID: PMC2923189 DOI: 10.1371/journal.pone.0012225] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2010] [Accepted: 07/22/2010] [Indexed: 12/01/2022] Open
Abstract
Background The Mycobacterium tuberculosis genome encodes two peptide transporters encoded by Rv3665c-Rv3662c and Rv1280c-Rv1283c. Both belong to the family of ABC transporters containing two nucleotide-binding subunits, two integral membrane proteins and one substrate-binding polypeptide. However, little is known about their functions in M. tuberculosis. Here we report functional characterization of the Rv1280c-Rv1283c-encoded transporter and its substrate-binding polypeptide OppAMTB. Methodology/Principal Findings OppAMTB was capable of binding the tripeptide glutathione and the nonapeptide bradykinin, indicative of a somewhat broad substrate specificity. Amino acid residues G109, N110, N230, D494 and F496, situated at the interface between domains I and III of OppA, were required for optimal peptide binding. Complementaton of an oppA knockout mutant of M. smegmatis with OppAMTB confirmed the role of this transporter in importing glutathione and the importance of the aforesaid amino acid residues in peptide transport. Interestingly, this transporter regulated the ability of M. tuberculosis to lower glutathione levels in infected compared to uninfected macrophages. This ability was partly offset by inactivation of oppD. Concomitantly, inactivation of oppD was associated with lowered levels of methyl glyoxal in infected macrophages and reduced apoptosis-inducing ability of the mutant. The ability to induce the production of the cytokines IL-1β, IL-6 and TNF-α was also compromised after inactivation of oppD. Conclusions Taken together, these studies uncover the novel observations that this peptide transporter modulates the innate immune response of macrophages infected with M. tuberculosis.
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Affiliation(s)
- Arunava Dasgupta
- Unité de Génétique Mycobactérienne, Institut Pasteur, Paris, France
| | | | - Devrani Mitra
- Department of Biotechnology, Indian Institute of Technology, Kharagpur, India
| | - Baisakhee Saha
- Department of Biotechnology, Indian Institute of Technology, Kharagpur, India
| | - Sourav Sanyal
- Department of Chemistry, Bose Institute, Kolkata, India
| | - Amit K. Das
- Department of Biotechnology, Indian Institute of Technology, Kharagpur, India
| | | | - Mary Jackson
- Unité de Génétique Mycobactérienne, Institut Pasteur, Paris, France
| | - Brigitte Gicquel
- Unité de Génétique Mycobactérienne, Institut Pasteur, Paris, France
| | | | - Joyoti Basu
- Department of Chemistry, Bose Institute, Kolkata, India
- * E-mail:
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