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Krysenko S, Wohlleben W. Polyamine and Ethanolamine Metabolism in Bacteria as an Important Component of Nitrogen Assimilation for Survival and Pathogenicity. Med Sci (Basel) 2022; 10:40. [PMID: 35997332 PMCID: PMC9397018 DOI: 10.3390/medsci10030040] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 07/23/2022] [Accepted: 07/25/2022] [Indexed: 11/16/2022] Open
Abstract
Nitrogen is an essential element required for bacterial growth. It serves as a building block for the biosynthesis of macromolecules and provides precursors for secondary metabolites. Bacteria have developed the ability to use various nitrogen sources and possess two enzyme systems for nitrogen assimilation involving glutamine synthetase/glutamate synthase and glutamate dehydrogenase. Microorganisms living in habitats with changeable availability of nutrients have developed strategies to survive under nitrogen limitation. One adaptation is the ability to acquire nitrogen from alternative sources including the polyamines putrescine, cadaverine, spermidine and spermine, as well as the monoamine ethanolamine. Bacterial polyamine and monoamine metabolism is not only important under low nitrogen availability, but it is also required to survive under high concentrations of these compounds. Such conditions can occur in diverse habitats such as soil, plant tissues and human cells. Strategies of pathogenic and non-pathogenic bacteria to survive in the presence of poly- and monoamines offer the possibility to combat pathogens by using their capability to metabolize polyamines as an antibiotic drug target. This work aims to summarize the knowledge on poly- and monoamine metabolism in bacteria and its role in nitrogen metabolism.
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Affiliation(s)
- Sergii Krysenko
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), Department of Microbiology and Biotechnology, University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany;
- Cluster of Excellence ‘Controlling Microbes to Fight Infections’, University of Tübingen, 72076 Tübingen, Germany
| | - Wolfgang Wohlleben
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), Department of Microbiology and Biotechnology, University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany;
- Cluster of Excellence ‘Controlling Microbes to Fight Infections’, University of Tübingen, 72076 Tübingen, Germany
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2
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Apiyo D, Mouton JM, Louw C, Sampson SL, Louw TM. Dynamic mathematical model development and validation of in vitro Mycobacterium smegmatis growth under nutrient- and pH-stress. J Theor Biol 2022; 532:110921. [PMID: 34582827 DOI: 10.1016/j.jtbi.2021.110921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 08/27/2021] [Accepted: 09/21/2021] [Indexed: 10/20/2022]
Abstract
Mycobacterium tuberculosis can exist within a host for lengthy periods, tolerating even antibiotic challenge. This non-heritable, antibiotic tolerant "persister" state, is thought to underlie latent Tuberculosis (TB) infection and a deeper understanding thereof could inform treatment strategies. In addition to experimental studies, mathematical and computational modelling approaches are widely employed to study persistence from both an in vivo and in vitro perspective. However, specialized models (partial differential equations, agent-based, multiscale, etc.) rely on several difficult to determine parameters. In this study, a dynamic mathematical model was developed to predict the response of Mycobacterium smegmatis (a model organism for M. tuberculosis) grown in batch culture and subjected to a range of in vitro environmental stresses. Lag phase dynamics, pH variations and internal nitrogen storage were mechanistically modelled. Experimental results were used to train model parameters using global optimization, with extensive subsequent model validation to ensure extensibility to more complex modelling frameworks. This included an identifiability analysis which indicated that seven of the thirteen model parameters were uniquely identifiable. Non-identifiable parameters were critically evaluated. Model predictions compared to validation data (based on experimental results not used during training) were accurate with less than 16% maximum absolute percentage error, indicating that the model is accurate even when extrapolating to new experimental conditions. The bulk growth model can be extended to spatially heterogeneous simulations such as an agent-based model to simulate in vitro granuloma models or, eventually, in vivo conditions, where distributed environmental conditions are difficult to measure.
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Affiliation(s)
- D Apiyo
- Department of Process Engineering, Faculty of Engineering, Stellenbosch University, Stellenbosch, South Africa
| | - J M Mouton
- Department of Science and Innovation/National Research Foundation (DSI/NRF) Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - C Louw
- Department of Process Engineering, Faculty of Engineering, Stellenbosch University, Stellenbosch, South Africa
| | - S L Sampson
- Department of Science and Innovation/National Research Foundation (DSI/NRF) Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - T M Louw
- Department of Process Engineering, Faculty of Engineering, Stellenbosch University, Stellenbosch, South Africa.
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3
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Pawełczyk J, Brzostek A, Minias A, Płociński P, Rumijowska-Galewicz A, Strapagiel D, Zakrzewska-Czerwińska J, Dziadek J. Cholesterol-dependent transcriptome remodeling reveals new insight into the contribution of cholesterol to Mycobacterium tuberculosis pathogenesis. Sci Rep 2021; 11:12396. [PMID: 34117327 PMCID: PMC8196197 DOI: 10.1038/s41598-021-91812-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 06/01/2021] [Indexed: 02/05/2023] Open
Abstract
Mycobacterium tuberculosis (Mtb) is an obligate human pathogen that can adapt to the various nutrients available during its life cycle. However, in the nutritionally stringent environment of the macrophage phagolysosome, Mtb relies mainly on cholesterol. In previous studies, we demonstrated that Mtb can accumulate and utilize cholesterol as the sole carbon source. However, a growing body of evidence suggests that a lipid-rich environment may have a much broader impact on the pathogenesis of Mtb infection than previously thought. Therefore, we applied high-resolution transcriptome profiling and the construction of various mutants to explore in detail the global effect of cholesterol on the tubercle bacillus metabolism. The results allow re-establishing the complete list of genes potentially involved in cholesterol breakdown. Moreover, we identified the modulatory effect of vitamin B12 on Mtb transcriptome and the novel function of cobalamin in cholesterol metabolite dissipation which explains the probable role of B12 in Mtb virulence. Finally, we demonstrate that a key role of cholesterol in mycobacterial metabolism is not only providing carbon and energy but involves also a transcriptome remodeling program that helps in developing tolerance to the unfavorable host cell environment far before specific stress-inducing phagosomal signals occur.
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Affiliation(s)
- Jakub Pawełczyk
- grid.413454.30000 0001 1958 0162Laboratory of Genetics and Physiology of Mycobacterium, Institute of Medical Biology, Polish Academy of Sciences, Łódź, Poland
| | - Anna Brzostek
- grid.413454.30000 0001 1958 0162Laboratory of Genetics and Physiology of Mycobacterium, Institute of Medical Biology, Polish Academy of Sciences, Łódź, Poland
| | - Alina Minias
- grid.413454.30000 0001 1958 0162Laboratory of Genetics and Physiology of Mycobacterium, Institute of Medical Biology, Polish Academy of Sciences, Łódź, Poland
| | - Przemysław Płociński
- grid.413454.30000 0001 1958 0162Laboratory of Genetics and Physiology of Mycobacterium, Institute of Medical Biology, Polish Academy of Sciences, Łódź, Poland ,grid.10789.370000 0000 9730 2769Department of Immunology and Infectious Biology, Faculty of Biology and Environmental Protection, University of Łódz, Łódź, Poland
| | - Anna Rumijowska-Galewicz
- grid.413454.30000 0001 1958 0162Laboratory of Genetics and Physiology of Mycobacterium, Institute of Medical Biology, Polish Academy of Sciences, Łódź, Poland
| | - Dominik Strapagiel
- grid.10789.370000 0000 9730 2769Biobank Lab, Department of Molecular Biophysics, Faculty of Biology and Environmental Protection, University of Lodz, Łódź, Poland
| | - Jolanta Zakrzewska-Czerwińska
- grid.8505.80000 0001 1010 5103Department of Molecular Microbiology, Faculty of Biotechnology, University of Wrocław, Wrocław, Poland
| | - Jarosław Dziadek
- grid.413454.30000 0001 1958 0162Laboratory of Genetics and Physiology of Mycobacterium, Institute of Medical Biology, Polish Academy of Sciences, Łódź, Poland
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Krysenko S, Matthews A, Busche T, Bera A, Wohlleben W. Poly- and Monoamine Metabolism in Streptomyces coelicolor: The New Role of Glutamine Synthetase-Like Enzymes in the Survival under Environmental Stress. Microb Physiol 2021; 31:233-247. [PMID: 34044403 DOI: 10.1159/000516644] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 04/17/2021] [Indexed: 11/19/2022]
Abstract
Soil bacteria from the genus Streptomyces, phylum Actinobacteria, feature a complex metabolism and diverse adaptations to environmental stress. These characteristics are consequences of variable nutrition availability in the soil and allow survival under changing nitrogen conditions. Streptomyces coelicolor is a model organism for Actinobacteria and is able to use nitrogen from a variety of sources including unusual compounds originating from the decomposition of dead plant and animal material, such as polyamines or monoamines (like ethanolamine). Assimilation of nitrogen from these sources in S. coelicolor remains largely unstudied. Using microbiological, biochemical and in silico approaches, it was recently possible to postulate polyamine and monoamine (ethanolamine) utilization pathways in S. coelicolor. Glutamine synthetase-like enzymes (GS-like) play a central role in these pathways. Extensive studies have revealed that these enzymes are able to detoxify polyamines or monoamines and allow the survival of S. coelicolor in soil containing an excess of these compounds. On the other hand, at low concentrations, polyamines and monoamines can be utilized as nitrogen and carbon sources. It has been demonstrated that the first step in poly-/monoamine assimilation is catalyzed by GlnA3 (a γ-glutamylpolyamine synthetase) and GlnA4 (a γ-glutamylethanolamide synthetase), respectively. First insights into the regulation of polyamine and ethanolamine metabolism have revealed that the expression of the glnA3 and the glnA4 gene are controlled on the transcriptional level.
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Affiliation(s)
- Sergii Krysenko
- Department of Microbiology and Biotechnology, Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), Cluster of Excellence 'Controlling Microbes to Fight Infections', University of Tübingen, Tübingen, Germany
| | - Arne Matthews
- Department of Microbiology and Biotechnology, Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), Cluster of Excellence 'Controlling Microbes to Fight Infections', University of Tübingen, Tübingen, Germany
| | - Tobias Busche
- Center for Biotechnology (CeBiTec), Bielefeld University, Bielefeld, Germany
| | - Agnieszka Bera
- Department of Microbiology and Biotechnology, Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), Cluster of Excellence 'Controlling Microbes to Fight Infections', University of Tübingen, Tübingen, Germany
| | - Wolfgang Wohlleben
- Department of Microbiology and Biotechnology, Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), Cluster of Excellence 'Controlling Microbes to Fight Infections', University of Tübingen, Tübingen, Germany
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5
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Gyamfi E, Narh CA, Quaye C, Abbass A, Dzudzor B, Mosi L. Microbiology of secondary infections in Buruli ulcer lesions; implications for therapeutic interventions. BMC Microbiol 2021; 21:4. [PMID: 33402095 PMCID: PMC7783985 DOI: 10.1186/s12866-020-02070-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 12/15/2020] [Indexed: 11/10/2022] Open
Abstract
Background Buruli ulcer (BU) is a skin disease caused by Mycobacterium ulcerans and is the second most common mycobacterial disease after tuberculosis in Ghana and Côte d’Ivoire. M. ulcerans produces mycolactone, an immunosuppressant macrolide toxin, responsible for the characteristic painless nature of the infection. Secondary infection of ulcers before, during and after treatment has been associated with delayed wound healing and resistance to streptomycin and rifampicin. However, not much is known of the bacteria causing these infections as well as antimicrobial drugs for treating the secondary microorganism. This study sought to identify secondary microbial infections in BU lesions and to determine their levels of antibiotic resistance due to the prolonged antibiotic therapy required for Buruli ulcer. Results Swabs from fifty-one suspected BU cases were sampled in the Amansie Central District from St. Peters Hospital (Jacobu) and through an active case surveillance. Forty of the samples were M. ulcerans (BU) positive. Secondary bacteria were identified in all sampled lesions (N = 51). The predominant bacteria identified in both BU and Non-BU groups were Staphylococci spp and Bacilli spp. The most diverse secondary bacteria were detected among BU patients who were not yet on antibiotic treatment. Fungal species identified were Candida spp, Penicillium spp and Trichodema spp. Selected secondary bacteria isolates were all susceptible to clarithromycin and amikacin among both BU and Non-BU patients. Majority, however, had high resistance to streptomycin. Conclusions Microorganisms other than M. ulcerans colonize and proliferate on BU lesions. Secondary microorganisms of BU wounds were mainly Staphylococcus spp, Bacillus spp and Pseudomonas spp. These secondary microorganisms were less predominant in BU patients under treatment compared to those without treatment. The delay in healing that are experienced by some BU patients could be as a result of these bacteria and fungi colonizing and proliferating in BU lesions. Clarithromycin and amikacin are likely suitable drugs for clearance of secondary infection of Buruli ulcer.
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Affiliation(s)
- Elizabeth Gyamfi
- Department of Medical Biochemistry, University of Ghana Medical School, Korle Bu, Accra, Ghana.,Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Legon, Accra, Ghana.,West African Center for Cell Biology of Infectious Pathogens, University of Ghana, Legon, Accra, Ghana
| | - Charles A Narh
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Accra, Ghana.,Burnet Institute for Medical Research, Melbourne, Australia
| | - Charles Quaye
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Accra, Ghana
| | - Adiza Abbass
- Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Legon, Accra, Ghana.,West African Center for Cell Biology of Infectious Pathogens, University of Ghana, Legon, Accra, Ghana
| | - Bartholomew Dzudzor
- Department of Medical Biochemistry, University of Ghana Medical School, Korle Bu, Accra, Ghana
| | - Lydia Mosi
- Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Legon, Accra, Ghana. .,West African Center for Cell Biology of Infectious Pathogens, University of Ghana, Legon, Accra, Ghana.
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6
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Intracellular Mycobacterium tuberculosis Exploits Multiple Host Nitrogen Sources during Growth in Human Macrophages. Cell Rep 2020; 29:3580-3591.e4. [PMID: 31825837 PMCID: PMC6915324 DOI: 10.1016/j.celrep.2019.11.037] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 07/05/2019] [Accepted: 11/07/2019] [Indexed: 02/05/2023] Open
Abstract
Nitrogen metabolism of Mycobacterium tuberculosis (Mtb) is crucial for the survival of this important pathogen in its primary human host cell, the macrophage, but little is known about the source(s) and their assimilation within this intracellular niche. Here, we have developed 15N-flux spectral ratio analysis (15N-FSRA) to explore Mtb’s nitrogen metabolism; we demonstrate that intracellular Mtb has access to multiple amino acids in the macrophage, including glutamate, glutamine, aspartate, alanine, glycine, and valine; and we identify glutamine as the predominant nitrogen donor. Each nitrogen source is uniquely assimilated into specific amino acid pools, indicating compartmentalized metabolism during intracellular growth. We have discovered that serine is not available to intracellular Mtb, and we show that a serine auxotroph is attenuated in macrophages. This work provides a systems-based tool for exploring the nitrogen metabolism of intracellular pathogens and highlights the enzyme phosphoserine transaminase as an attractive target for the development of novel anti-tuberculosis therapies. Mycobacterium tuberculosis utilizes multiple amino acids as nitrogen sources in human macrophages 15N-FSRA tool identified the intracellular nitrogen sources Glutamine is the predominant nitrogen donor for M. tuberculosis Serine biosynthesis is essential for the survival of intracellular M. tuberculosis
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7
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Combining proteogenomics and metaproteomics for deep taxonomic and functional characterization of microbiomes from a non-sequenced host. NPJ Biofilms Microbiomes 2020; 6:23. [PMID: 32504001 PMCID: PMC7275042 DOI: 10.1038/s41522-020-0133-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Accepted: 05/07/2020] [Indexed: 02/06/2023] Open
Abstract
Metaproteomics of gut microbiomes from animal hosts lacking a reference genome is challenging. Here we describe a strategy combining high-resolution metaproteomics and host RNA sequencing (RNA-seq) with generalist database searching to survey the digestive tract of Gammarus fossarum, a small crustacean used as a sentinel species in ecotoxicology. This approach provides a deep insight into the full range of biomasses and metabolic activities of the holobiont components, and differentiates between the intestine and hepatopancreatic caecum.
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8
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Achlatis M, Pernice M, Green K, Guagliardo P, Kilburn MR, Hoegh-Guldberg O, Dove S. Single-cell measurement of ammonium and bicarbonate uptake within a photosymbiotic bioeroding sponge. THE ISME JOURNAL 2018; 12:1308-1318. [PMID: 29386628 PMCID: PMC5932049 DOI: 10.1038/s41396-017-0044-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 12/12/2017] [Indexed: 01/04/2023]
Abstract
Some of the most aggressive coral-excavating sponges host intracellular dinoflagellates from the genus Symbiodinium, which are hypothesized to provide the sponges with autotrophic energy that powers bioerosion. Investigations of the contribution of Symbiodinium to host metabolism and particularly inorganic nutrient recycling are complicated, however, by the presence of alternative prokaryotic candidates for this role. Here, novel methods are used to study nutrient assimilation and transfer within and between the outer-layer cells of the Indopacific bioeroding sponge Cliona orientalis. Combining stable isotope labelling, transmission electron microscopy (TEM) and nanoscale secondary ion mass spectrometry (NanoSIMS), we visualize and measure metabolic activity at the individual cell level, tracking the fate of 15N-ammonium and 13C-bicarbonate within the intact holobiont. We found strong uptake of both inorganic sources (especially 13C-bicarbonate) by Symbiodinium cells. Labelled organic nutrients were translocated from Symbiodinium to the Symbiodinium-hosting sponge cells within 6 h, and occasionally to other sponge cells within 3 days. By contrast, prokaryotic symbionts were not observed to participate in inorganic nutrient assimilation in the outer layers of the sponge. Our findings strongly support the metabolic interaction between the sponge and dinoflagellates, shedding light on the ecological advantages and adaptive capacity of photosymbiotic bioeroding sponges in oligotrophic marine habitats.
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Affiliation(s)
- Michelle Achlatis
- School of Biological Sciences, Coral Reef Ecosystems Laboratory, The University of Queensland, St. Lucia, QLD, 4072, Australia.
- Australian Research Council Centre of Excellence for Coral Reef Studies, The University of Queensland, St. Lucia, QLD, 4072, Australia.
- Global Change Institute, The University of Queensland, St. Lucia, QLD, 4072, Australia.
| | - Mathieu Pernice
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, 2007, Australia.
| | - Kathryn Green
- Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Paul Guagliardo
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Perth, WA, 6009, Australia
| | - Matthew R Kilburn
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Perth, WA, 6009, Australia
| | - Ove Hoegh-Guldberg
- School of Biological Sciences, Coral Reef Ecosystems Laboratory, The University of Queensland, St. Lucia, QLD, 4072, Australia
- Australian Research Council Centre of Excellence for Coral Reef Studies, The University of Queensland, St. Lucia, QLD, 4072, Australia
- Global Change Institute, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Sophie Dove
- School of Biological Sciences, Coral Reef Ecosystems Laboratory, The University of Queensland, St. Lucia, QLD, 4072, Australia
- Australian Research Council Centre of Excellence for Coral Reef Studies, The University of Queensland, St. Lucia, QLD, 4072, Australia
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9
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Wang S, Yang F, Yang B. Global effect of CsrA on gene expression in enterohemorrhagic Escherichia coli O157:H7. Res Microbiol 2017; 168:700-709. [PMID: 28870757 DOI: 10.1016/j.resmic.2017.08.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 08/21/2017] [Accepted: 08/23/2017] [Indexed: 01/25/2023]
Abstract
The post-transcriptional regulator CsrA regulates multiple unrelated processes such as central carbon metabolism, motility, biofilm formation and bacterial virulence in different bacteria. However, regulation by CsrA in enterohemorrhagic Escherichia coli (EHEC) O157:H7 is still largely unknown. In this study, we performed a detailed analysis of gene expression differences between the EHEC O157:H7 wild-type strain and a corresponding csrA::kan mutant using RNA-seq technology. Genes whose expression was affected by CsrA were identified and grouped into different clusters of orthologous group categories. Genes located in the locus of enterocyte effacement (LEE) pathogenicity island were significantly upregulated, whereas expression of flagella-related genes was significantly reduced in the csrA::kan mutant. Subsequent bacterial adherence and motility assays showed that inactivation of CsrA in EHEC O157:H7 resulted in a significant increase in bacterial adherence to host epithelial cells, with a concomitant loss of swimming motility on semi-solid agar plates. Furthermore, we also found that CsrA regulates genes not previously identified in other bacterial species, including genes encoding cytochrome oxidases and those required for nitrogen metabolism. Our results provide essential insight into the regulatory function of CsrA.
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Affiliation(s)
- Shaomeng Wang
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin 300457, PR China.
| | - Fan Yang
- Department of Neurosurgery, Tianjin First Central Hospital, Tianjin 300192, PR China.
| | - Bin Yang
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin 300457, PR China.
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10
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Petridis M, Vickers C, Robson J, McKenzie JL, Bereza M, Sharrock A, Aung HL, Arcus VL, Cook GM. Structure and Function of AmtR in Mycobacterium smegmatis: Implications for Post-Transcriptional Regulation of Urea Metabolism through a Small Antisense RNA. J Mol Biol 2016; 428:4315-4329. [PMID: 27640309 DOI: 10.1016/j.jmb.2016.09.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2016] [Revised: 09/02/2016] [Accepted: 09/07/2016] [Indexed: 01/19/2023]
Abstract
Soil-dwelling bacteria of the phylum actinomycetes generally harbor either GlnR or AmtR as a global regulator of nitrogen metabolism. Mycobacterium smegmatis harbors both of these canonical regulators; GlnR regulates the expression of key genes involved in nitrogen metabolism, while the function and signal transduction pathway of AmtR in M. smegmatis remains largely unknown. Here, we report the structure and function of the M. smegmatis AmtR and describe the role of AmtR in the regulation of nitrogen metabolism in response to nitrogen availability. To determine the function of AmtR in M. smegmatis, we performed genome-wide expression profiling comparing the wild-type versus an ∆amtR mutant and identified significant changes in the expression of 11 genes, including an operon involved in urea degradation. An AmtR consensus-binding motif (CTGTC-N4-GACAG) was identified in the promoter region of this operon, and ligand-independent, high-affinity AmtR binding was validated by both electrophoretic mobility shift assays and surface plasmon resonance measurements. We confirmed the transcription of a cis-encoded small RNA complementary to the gene encoding AmtR under nitrogen excess, and we propose a post-transcriptional regulatory mechanism for AmtR. The three-dimensional X-ray structure of AmtR at 2.0Å revealed an overall TetR-like dimeric structure, and the alignment of the M. smegmatis AmtR and Corynebacterium glutamicum AmtR regulatory domains showed poor structural conservation, providing a potential explanation for the lack of M. smegmatis AmtR interaction with the adenylylated PII protein. Taken together, our data suggest an AmtR (repressor)/GlnR (activator) competitive binding mechanism for transcriptional regulation of urea metabolism that is controlled by a cis-encoded small antisense RNA.
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Affiliation(s)
- Michael Petridis
- Department of Microbiology and Immunology, Otago School of Medical Sciences, University of Otago, Dunedin 9054, New Zealand.
| | - Chelsea Vickers
- Department of Biological Sciences, University of Waikato, Hamilton 3240, New Zealand.
| | - Jennifer Robson
- Department of Microbiology and Immunology, Otago School of Medical Sciences, University of Otago, Dunedin 9054, New Zealand.
| | - Joanna L McKenzie
- Department of Biological Sciences, University of Waikato, Hamilton 3240, New Zealand.
| | - Magdalena Bereza
- Department of Biological Sciences, University of Waikato, Hamilton 3240, New Zealand.
| | - Abigail Sharrock
- Department of Biological Sciences, University of Waikato, Hamilton 3240, New Zealand.
| | - Htin Lin Aung
- Department of Microbiology and Immunology, Otago School of Medical Sciences, University of Otago, Dunedin 9054, New Zealand.
| | - Vickery L Arcus
- Department of Biological Sciences, University of Waikato, Hamilton 3240, New Zealand.
| | - Gregory M Cook
- Department of Microbiology and Immunology, Otago School of Medical Sciences, University of Otago, Dunedin 9054, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Private Bag 92019, Auckland 1042, New Zealand.
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11
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Williams KJ, Jenkins VA, Barton GR, Bryant WA, Krishnan N, Robertson BD. Deciphering the metabolic response of Mycobacterium tuberculosis to nitrogen stress. Mol Microbiol 2015; 97:1142-57. [PMID: 26077160 PMCID: PMC4950008 DOI: 10.1111/mmi.13091] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/12/2014] [Indexed: 12/21/2022]
Abstract
A key component to the success of Mycobacterium tuberculosis as a pathogen is the ability to sense and adapt metabolically to the diverse range of conditions encountered in vivo, such as oxygen tension, environmental pH and nutrient availability. Although nitrogen is an essential nutrient for every organism, little is known about the genes and pathways responsible for nitrogen assimilation in M. tuberculosis. In this study we have used transcriptomics and chromatin immunoprecipitation and high‐throughput sequencing to address this. In response to nitrogen starvation, a total of 185 genes were significantly differentially expressed (96 up‐regulated and 89 down regulated; 5% genome) highlighting several significant areas of metabolic change during nitrogen limitation such as nitrate/nitrite metabolism, aspartate metabolism and changes in cell wall biosynthesis. We identify GlnR as a regulator involved in the nitrogen response, controlling the expression of at least 33 genes in response to nitrogen limitation. We identify a consensus GlnR binding site and relate its location to known transcriptional start sites. We also show that the GlnR response regulator plays a very different role in M. tuberculosis to that in non‐pathogenic mycobacteria, controlling genes involved in nitric oxide detoxification and intracellular survival instead of genes involved in nitrogen scavenging.
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Affiliation(s)
- Kerstin J Williams
- MRC Centre for Molecular Bacteriology and Infection, Department of Medicine, Imperial College London, London, SW7 2AZ, UK
| | - Victoria A Jenkins
- MRC Centre for Molecular Bacteriology and Infection, Department of Medicine, Imperial College London, London, SW7 2AZ, UK
| | - Geraint R Barton
- Centre for Integrative Systems Biology and Bioinformatics, Imperial College London, London, SW7 2AZ, UK
| | - William A Bryant
- Centre for Integrative Systems Biology and Bioinformatics, Imperial College London, London, SW7 2AZ, UK
| | - Nitya Krishnan
- MRC Centre for Molecular Bacteriology and Infection, Department of Medicine, Imperial College London, London, SW7 2AZ, UK
| | - Brian D Robertson
- MRC Centre for Molecular Bacteriology and Infection, Department of Medicine, Imperial College London, London, SW7 2AZ, UK.,Centre for Integrative Systems Biology and Bioinformatics, Imperial College London, London, SW7 2AZ, UK
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12
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Uddin R, Saeed K, Khan W, Azam SS, Wadood A. Metabolic pathway analysis approach: Identification of novel therapeutic target against methicillin resistant Staphylococcus aureus. Gene 2015; 556:213-26. [DOI: 10.1016/j.gene.2014.11.056] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Revised: 11/18/2014] [Accepted: 11/25/2014] [Indexed: 12/31/2022]
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Polónia ARM, Cleary DFR, Freitas R, de Voogd NJ, Gomes NCM. The putative functional ecology and distribution of archaeal communities in sponges, sediment and seawater in a coral reef environment. Mol Ecol 2015; 24:409-23. [DOI: 10.1111/mec.13024] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2014] [Revised: 11/23/2014] [Accepted: 11/26/2014] [Indexed: 01/08/2023]
Affiliation(s)
- Ana R. M. Polónia
- Department of Biology; CESAM; Universidade de Aveiro; Campus Universitário de Santiago 3810-193 Aveiro Portugal
| | - Daniel F. R. Cleary
- Department of Biology; CESAM; Universidade de Aveiro; Campus Universitário de Santiago 3810-193 Aveiro Portugal
| | - Rossana Freitas
- Department of Biology; CESAM; Universidade de Aveiro; Campus Universitário de Santiago 3810-193 Aveiro Portugal
| | - Nicole J. de Voogd
- Naturalis Biodiversity Center; PO Box 9517 2300 RA Leiden The Netherlands
| | - Newton C. M. Gomes
- Department of Biology; CESAM; Universidade de Aveiro; Campus Universitário de Santiago 3810-193 Aveiro Portugal
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14
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Gouzy A, Larrouy-Maumus G, Bottai D, Levillain F, Dumas A, Wallach JB, Caire-Brandli I, de Chastellier C, Wu TD, Poincloux R, Brosch R, Guerquin-Kern JL, Schnappinger D, Sório de Carvalho LP, Poquet Y, Neyrolles O. Mycobacterium tuberculosis exploits asparagine to assimilate nitrogen and resist acid stress during infection. PLoS Pathog 2014; 10:e1003928. [PMID: 24586151 PMCID: PMC3930563 DOI: 10.1371/journal.ppat.1003928] [Citation(s) in RCA: 119] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Accepted: 12/31/2013] [Indexed: 11/19/2022] Open
Abstract
Mycobacterium tuberculosis is an intracellular pathogen. Within macrophages, M. tuberculosis thrives in a specialized membrane-bound vacuole, the phagosome, whose pH is slightly acidic, and where access to nutrients is limited. Understanding how the bacillus extracts and incorporates nutrients from its host may help develop novel strategies to combat tuberculosis. Here we show that M. tuberculosis employs the asparagine transporter AnsP2 and the secreted asparaginase AnsA to assimilate nitrogen and resist acid stress through asparagine hydrolysis and ammonia release. While the role of AnsP2 is partially spared by yet to be identified transporter(s), that of AnsA is crucial in both phagosome acidification arrest and intracellular replication, as an M. tuberculosis mutant lacking this asparaginase is ultimately attenuated in macrophages and in mice. Our study provides yet another example of the intimate link between physiology and virulence in the tubercle bacillus, and identifies a novel pathway to be targeted for therapeutic purposes.
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Affiliation(s)
- Alexandre Gouzy
- Centre National de la Recherche Scientifique, Institut de Pharmacologie et de Biologie Structurale, Toulouse, France
- Université de Toulouse, Université Paul Sabatier, Institut de Pharmacologie et de Biologie Structurale, Toulouse, France
| | - Gérald Larrouy-Maumus
- Mycobacterial Research Division, MRC National Institute for Medical Research, London, United Kingdom
| | - Daria Bottai
- Dipartimento di Ricerca Traslazionale e delle Nuove Tecnologie in Medicina e Chirurgia, Università di Pisa, Pisa, Italy
| | - Florence Levillain
- Centre National de la Recherche Scientifique, Institut de Pharmacologie et de Biologie Structurale, Toulouse, France
- Université de Toulouse, Université Paul Sabatier, Institut de Pharmacologie et de Biologie Structurale, Toulouse, France
| | - Alexia Dumas
- Centre National de la Recherche Scientifique, Institut de Pharmacologie et de Biologie Structurale, Toulouse, France
- Université de Toulouse, Université Paul Sabatier, Institut de Pharmacologie et de Biologie Structurale, Toulouse, France
| | - Joshua B. Wallach
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York, United States of America
| | - Irène Caire-Brandli
- Centre d'Immunologie de Marseille-Luminy (CIML), Inserm UMR 1104, CNRS UMR 7280, Aix-Marseille University UM 2, Marseille, France
| | - Chantal de Chastellier
- Centre d'Immunologie de Marseille-Luminy (CIML), Inserm UMR 1104, CNRS UMR 7280, Aix-Marseille University UM 2, Marseille, France
| | - Ting-Di Wu
- Institut Curie, Laboratoire de Microscopie Ionique, Orsay, France
- INSERM U759, Orsay, France
| | - Renaud Poincloux
- Centre National de la Recherche Scientifique, Institut de Pharmacologie et de Biologie Structurale, Toulouse, France
- Université de Toulouse, Université Paul Sabatier, Institut de Pharmacologie et de Biologie Structurale, Toulouse, France
| | - Roland Brosch
- Institut Pasteur, Unité de Pathogénomique Mycobactérienne Intégrée, Paris, France
| | - Jean-Luc Guerquin-Kern
- Institut Curie, Laboratoire de Microscopie Ionique, Orsay, France
- INSERM U759, Orsay, France
| | - Dirk Schnappinger
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York, United States of America
| | | | - Yannick Poquet
- Centre National de la Recherche Scientifique, Institut de Pharmacologie et de Biologie Structurale, Toulouse, France
- Université de Toulouse, Université Paul Sabatier, Institut de Pharmacologie et de Biologie Structurale, Toulouse, France
| | - Olivier Neyrolles
- Centre National de la Recherche Scientifique, Institut de Pharmacologie et de Biologie Structurale, Toulouse, France
- Université de Toulouse, Université Paul Sabatier, Institut de Pharmacologie et de Biologie Structurale, Toulouse, France
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15
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Viljoen AJ, Kirsten CJ, Baker B, van Helden PD, Wiid IJF. The role of glutamine oxoglutarate aminotransferase and glutamate dehydrogenase in nitrogen metabolism in Mycobacterium bovis BCG. PLoS One 2013; 8:e84452. [PMID: 24367660 PMCID: PMC3868603 DOI: 10.1371/journal.pone.0084452] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 11/15/2013] [Indexed: 01/18/2023] Open
Abstract
Recent evidence suggests that the regulation of intracellular glutamate levels could play an important role in the ability of pathogenic slow-growing mycobacteria to grow in vivo. However, little is known about the in vitro requirement for the enzymes which catalyse glutamate production and degradation in the slow-growing mycobacteria, namely; glutamine oxoglutarate aminotransferase (GOGAT) and glutamate dehydrogenase (GDH), respectively. We report that allelic replacement of the Mycobacterium bovis BCG gltBD-operon encoding for the large (gltB) and small (gltD) subunits of GOGAT with a hygromycin resistance cassette resulted in glutamate auxotrophy and that deletion of the GDH encoding-gene (gdh) led to a marked growth deficiency in the presence of L-glutamate as a sole nitrogen source as well as reduction in growth when cultured in an excess of L-asparagine.
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Affiliation(s)
- Albertus J. Viljoen
- DST/NRF Centre of Excellence for Biomedical Tuberculosis Research, MRC Centre for Molecular and Cellular Biology, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Tygerberg, Cape Town, South Africa
- *
| | - Catriona J. Kirsten
- DST/NRF Centre of Excellence for Biomedical Tuberculosis Research, MRC Centre for Molecular and Cellular Biology, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Tygerberg, Cape Town, South Africa
| | - Bienyameen Baker
- DST/NRF Centre of Excellence for Biomedical Tuberculosis Research, MRC Centre for Molecular and Cellular Biology, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Tygerberg, Cape Town, South Africa
| | - Paul D. van Helden
- DST/NRF Centre of Excellence for Biomedical Tuberculosis Research, MRC Centre for Molecular and Cellular Biology, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Tygerberg, Cape Town, South Africa
| | - Ian J. F. Wiid
- DST/NRF Centre of Excellence for Biomedical Tuberculosis Research, MRC Centre for Molecular and Cellular Biology, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Tygerberg, Cape Town, South Africa
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Tripathi D, Chandra H, Bhatnagar R. Poly-L-glutamate/glutamine synthesis in the cell wall of Mycobacterium bovis is regulated in response to nitrogen availability. BMC Microbiol 2013; 13:226. [PMID: 24112767 PMCID: PMC3852478 DOI: 10.1186/1471-2180-13-226] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Accepted: 10/08/2013] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND The cell wall of pathogenic mycobacteria is known to possess poly-L-glutamine (PLG) layer. PLG synthesis has been directly linked to glutamine synthetase (GS) enzyme. glnA1 gene encodes for GS enzyme in mycobacteria. PLG layer is absent in cell wall of avirulent Mycobacterium smegmatis, although M. smegmatis strain expressing GS enzyme of pathogenic mycobacteria can synthesize PLG layer in the cell wall. The role of GS enzyme has been extensively studied in Mycobacterium tuberculosis, however, little is known about GS enzyme in other mycobacterial species. Mycobacterium bovis, as an intracellular pathogen encounters nitrogen stress inside macrophages, thus it has developed nitrogen assimilatory pathways to survive in adverse conditions. We have investigated the expression and activity of M. bovis GS in response to nitrogen availability and effect on synthesis of PLG layer in the cell wall. M. smegmatis was used as a model to study the behaviour of glnA1 locus of M. bovis. RESULTS We observed that GS expression and activity decreased significantly in high nitrogen grown conditions. In high nitrogen conditions, the amount of PLG in cell wall was drastically reduced (below detectable limits) as compared to low nitrogen condition in M. bovis and in M. smegmatis strain complemented with M. bovis glnA1. Additionally, biofilm formation by M. smegmatis strain complemented with M. bovis glnA1 was increased than the wild type M. smegmatis strain. CONCLUSIONS The physiological regulation of GS in M. bovis was found to be similar to that reported in other mycobacteria but this data revealed that PLG synthesis in the cell wall of pathogenic mycobacteria occurs only in nitrogen limiting conditions and on the contrary high nitrogen conditions inhibit PLG synthesis. This indicates that PLG synthesis may be a form of nitrogen assimilatory pathway during ammonium starvation in virulent mycobacteria. Also, we have found that M. smegmatis complemented with M. bovis glnA1 was more efficient in biofilm formation than the wild type strain. This indicates that PLG layer favors biofilm formation. This study demonstrate that the nitrogen availability not only regulates GS expression and activity in M. bovis but also affects cell surface properties by modulating synthesis of PLG.
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Affiliation(s)
- Deeksha Tripathi
- Molecular Biology and Genetic Engineering Laboratory, School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India
| | - Harish Chandra
- Molecular Biology and Genetic Engineering Laboratory, School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India
| | - Rakesh Bhatnagar
- Molecular Biology and Genetic Engineering Laboratory, School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India
- Mailing address: School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India
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17
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Williams KJ, Bryant WA, Jenkins VA, Barton GR, Witney AA, Pinney JW, Robertson BD. Deciphering the response of Mycobacterium smegmatis to nitrogen stress using bipartite active modules. BMC Genomics 2013; 14:436. [PMID: 23819599 PMCID: PMC3706326 DOI: 10.1186/1471-2164-14-436] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Accepted: 06/20/2013] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND The ability to adapt to environments with fluctuating nutrient availability is vital for bacterial survival. Although essential for growth, few nitrogen metabolism genes have been identified or fully characterised in mycobacteria and nitrogen stress survival mechanisms are unknown. RESULTS A global transcriptional analysis of the mycobacterial response to nitrogen stress, showed a significant change in the differential expression of 16% of the Mycobacterium smegmatis genome. Gene expression changes were mapped onto the metabolic network using Active Modules for Bipartite Networks (AMBIENT) to identify metabolic pathways showing coordinated transcriptional responses to the stress. AMBIENT revealed several key features of the metabolic response not identified by KEGG enrichment alone. Down regulated reactions were associated with the general reduction in cellular metabolism as a consequence of reduced growth rate. Up-regulated modules highlighted metabolic changes in nitrogen assimilation and scavenging, as well as reactions involved in hydrogen peroxide metabolism, carbon scavenging and energy generation. CONCLUSIONS Application of an Active Modules algorithm to transcriptomic data identified key metabolic reactions and pathways altered in response to nitrogen stress, which are central to survival under nitrogen limiting environments.
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Affiliation(s)
- Kerstin J Williams
- Department of Medicine, MRC Centre for Molecular Bacteriology and Infection, South Kensington, London SW7 2AZ, UK
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Jenkins VA, Barton GR, Robertson BD, Williams KJ. Genome wide analysis of the complete GlnR nitrogen-response regulon in Mycobacterium smegmatis. BMC Genomics 2013; 14:301. [PMID: 23642041 PMCID: PMC3662644 DOI: 10.1186/1471-2164-14-301] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 04/29/2013] [Indexed: 11/24/2022] Open
Abstract
Background Nitrogen is an essential element for bacterial growth and an important component of biological macromolecules. Consequently, responding to nitrogen limitation is critical for bacterial survival and involves the interplay of signalling pathways and transcriptional regulation of nitrogen assimilation and scavenging genes. In the soil dwelling saprophyte Mycobacterium smegmatis the OmpR-type response regulator GlnR is thought to mediate the transcriptomic response to nitrogen limitation. However, to date only ten genes have been shown to be in the GlnR regulon, a vastly reduced number compared to other organisms. Results We investigated the role of GlnR in the nitrogen limitation response and determined the entire GlnR regulon, by combining expression profiling of M. smegmatis wild type and glnR deletion mutant, with GlnR-specific chromatin immunoprecipitation and high throughput sequencing. We identify 53 GlnR binding sites during nitrogen limitation that control the expression of over 100 genes, demonstrating that GlnR is the regulator controlling the assimilation and utilisation of nitrogen. We also determine a consensus GlnR binding motif and identify key residues within the motif that are required for specific GlnR binding. Conclusions We have demonstrated that GlnR is the global nitrogen response regulator in M. smegmatis, directly regulating the expression of more than 100 genes. GlnR controls key nitrogen stress survival processes including primary nitrogen metabolism pathways, the ability to utilise nitrate and urea as alternative nitrogen sources, and the potential to use cellular components to provide a source of ammonium. These studies further our understanding of how mycobacteria survive nutrient limiting conditions.
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Affiliation(s)
- Victoria A Jenkins
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, South Kensington, London SW7 2AZ, UK
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van Wezel GP, McDowall KJ. The regulation of the secondary metabolism of Streptomyces: new links and experimental advances. Nat Prod Rep 2011; 28:1311-33. [PMID: 21611665 DOI: 10.1039/c1np00003a] [Citation(s) in RCA: 315] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Streptomycetes and other actinobacteria are renowned as a rich source of natural products of clinical, agricultural and biotechnological value. They are being mined with renewed vigour, supported by genome sequencing efforts, which have revealed a coding capacity for secondary metabolites in vast excess of expectations that were based on the detection of antibiotic activities under standard laboratory conditions. Here we review what is known about the control of production of so-called secondary metabolites in streptomycetes, with an emphasis on examples where details of the underlying regulatory mechanisms are known. Intriguing links between nutritional regulators, primary and secondary metabolism and morphological development are discussed, and new data are included on the carbon control of development and antibiotic production, and on aspects of the regulation of the biosynthesis of microbial hormones. Given the tide of antibiotic resistance emerging in pathogens, this review is peppered with approaches that may expand the screening of streptomycetes for new antibiotics by awakening expression of cryptic antibiotic biosynthetic genes. New technologies are also described that have potential to greatly further our understanding of gene regulation in what is an area fertile for discovery and exploitation
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Lewis RA, Shahi SK, Laing E, Bucca G, Efthimiou G, Bushell M, Smith CP. Genome-wide transcriptomic analysis of the response to nitrogen limitation in Streptomyces coelicolor A3(2). BMC Res Notes 2011; 4:78. [PMID: 21429225 PMCID: PMC3073908 DOI: 10.1186/1756-0500-4-78] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Accepted: 03/23/2011] [Indexed: 12/03/2022] Open
Abstract
Background The present study represents a genome-wide transcriptomic analysis of the response of the model streptomycete Streptomyces coelicolor A3(2) M145 to fermentor culture in Modified Evans Media limited, respectively, for nitrogen, phosphate and carbon undertaken as part of the ActinoGEN consortium to provide a publicly available reference microarray dataset. Findings A microarray dataset using samples from two replicate cultures for each nutrient limitation was generated. In this report our analysis has focused on the genes which are significantly differentially expressed, as determined by Rank Products Analysis, between samples from matched time points correlated by growth phase for the three pairs of differently limited culture datasets. With a few exceptions, genes are only significantly differentially expressed between the N6/N7 time points and their corresponding time points in the C and P-limited cultures, with the vast majority of the differentially expressed genes being more highly expressed in the N-limited cultures. Our analysis of these genes indicated expression of several members of the GlnR regulon are induced upon nitrogen limitation, as assayed for by [NH4+] measurements, and we are able to identify several additional genes not present in the GlnR regulon whose expression is induced in response to nitrogen limitation. We also note SCO3327 which encodes a small protein (32 amino acid residues) unusually rich in the basic amino acids lysine (31.25%) and arginine (25%) is significantly differentially expressed in the nitrogen limited cultures. Additionally, we investigate the expression of known members of the GlnR regulon and the relationship between gene organization and expression for the SCO2486-SCO2487 and SCO5583-SCO5585 operons. Conclusions We provide a list of genes whose expression is differentially expressed in low nitrogen culture conditions, including a putative nitrogen storage protein encoded by SCO3327. Our list includes several genes whose expression patterns are similar to up-regulated members of the GlnR regulon and are induced in response to nitrogen limitation. These genes represent likely targets for future studies into the nitrogen starvation response in Streptomyces coelicolor.
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Affiliation(s)
- Richard A Lewis
- Faculty of Heath & Medical Sciences, University of Surrey, Stag Hill, Guildford, Surrey, GU2 7XH, UK.
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Diversity of metabolic shift in response to oxygen deprivation in Corynebacterium glutamicum and its close relatives. Appl Microbiol Biotechnol 2011; 90:1051-61. [PMID: 21327408 DOI: 10.1007/s00253-011-3144-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2010] [Revised: 01/18/2011] [Accepted: 01/19/2011] [Indexed: 10/18/2022]
Abstract
Oxygen-deprived Corynebacterium glutamicum R cells remain metabolically active, producing considerable amounts of organic acids even when not actively growing. We compared the proficiencies of C. glutamicum and close relatives grown under aerobic conditions to metabolize glucose when deprived of oxygen. Eight strains that readily consumed glucose without cell growth subsequently produced organic acids. Among these, the glucose consumption rates of the two C. glutamicum strains (>40 mM/h) and Corynebacterium efficiens (>12 mM/h) were an order of magnitude higher than those of the other five strains. The resultant organic acid yields of these three strains (>86%) consequently exceeded those of the other five (<60%). This difference is probably rooted in the comparatively inferior activities of glyceraldehyde-3-phosphate dehydrogenase, lactate dehydrogenase, and malate dehydrogenase observed in the five strains. Moreover, under oxygen deprivation, phosphoenolpyruvate carboxylase (PEPC) activity of C. efficiens was elevated tenfold, but its lack of fumarase activity meant that no succinic acid could be produced. The metabolic shift occasioned by addition of the PEPC substrate sodium bicarbonate resulted in a doubling of the glucose consumption rate of the two C. glutamicum strains but not that of the other six close relatives.
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Chandra H, Basir SF, Gupta M, Banerjee N. Glutamine synthetase encoded by glnA-1 is necessary for cell wall resistance and pathogenicity of Mycobacterium bovis. MICROBIOLOGY-SGM 2010; 156:3669-3677. [PMID: 20724386 DOI: 10.1099/mic.0.043828-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Pathogenic strains of mycobacteria produce copious amounts of glutamine synthetase (GS) in the culture medium. The enzyme activity is linked to synthesis of poly-α-l-glutamine (PLG) in the cell walls. This study describes a glnA-1 mutant of Mycobacterium bovis that produces reduced levels of GS. The mutant was able to grow in enriched 7H9 medium without glutamine supplementation. The glnA-1 strain contained no detectable PLG in the cell walls and showed marked sensitivity to different chemical and physical stresses such as lysozyme, SDS and sonication. The sensitivity of the mutant to two antitubercular drugs, rifampicin and d-cycloserine, was also increased. The glnA-1 strain infected THP-1 cells with reduced efficiency and was also attenuated for growth in macrophages. A Mycobacterium smegmatis strain containing the M. bovis glnA-1 gene survived longer in THP-1 cells than the wild-type strain and also produced cell wall-associated PLG. The M. bovis mutant was not able to replicate in the organs of BALB/c mice and was cleared within 4-6 weeks of infection. Disruption of the glnA-1 gene adversely affected biofilm formation on polystyrene surfaces. The results of this study demonstrate that the absence of glnA-1 not only attenuates the pathogen but also affects cell surface properties by altering the cell wall chemistry of the organism via the synthesis of PLG; this may be a target for drug development.
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Affiliation(s)
- Harish Chandra
- International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Seemi Farhat Basir
- Department of Biosciences, Jamia Millia Islamia, New Delhi 110025, India
| | - Manish Gupta
- International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Nirupama Banerjee
- International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067, India
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Harper CJ, Hayward D, Kidd M, Wiid I, van Helden P. Glutamate dehydrogenase and glutamine synthetase are regulated in response to nitrogen availability in Myocbacterium smegmatis. BMC Microbiol 2010; 10:138. [PMID: 20459763 PMCID: PMC2881912 DOI: 10.1186/1471-2180-10-138] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2010] [Accepted: 05/11/2010] [Indexed: 11/21/2022] Open
Abstract
Background The assimilation of nitrogen is an essential process in all prokaryotes, yet a relatively limited amount of information is available on nitrogen metabolism in the mycobacteria. The physiological role and pathogenic properties of glutamine synthetase (GS) have been extensively investigated in Mycobacterium tuberculosis. However, little is known about this enzyme in other mycobacterial species, or the role of an additional nitrogen assimilatory pathway via glutamate dehydrogenase (GDH), in the mycobacteria as a whole. We investigated specific enzyme activity and transcription of GS and as well as both possible isoforms of GDH (NAD+- and NADP+-specific GDH) under varying conditions of nitrogen availability in Mycobacterium smegmatis as a model for the mycobacteria. Results It was found that the specific activity of the aminating NADP+-GDH reaction and the deaminating NAD+-GDH reaction did not change appreciably in response to nitrogen availability. However, GS activity as well as the deaminating NADP+-GDH and aminating NAD+-GDH reactions were indeed significantly altered in response to exogenous nitrogen concentrations. Transcription of genes encoding for GS and the GDH isoforms were also found to be regulated under our experimental conditions. Conclusions The physiological role and regulation of GS in M. smegmatis was similar to that which has been described for other mycobacteria, however, in our study the regulation of both NADP+- and NAD+-GDH specific activity in M. smegmatis appeared to be different to that of other Actinomycetales. It was found that NAD+-GDH played an important role in nitrogen assimilation rather than glutamate catabolism as was previously thought, and is it's activity appeared to be regulated in response to nitrogen availability. Transcription of the genes encoding for NAD+-GDH enzymes seem to be regulated in M. smegmatis under the conditions tested and may contribute to the changes in enzyme activity observed, however, our results indicate that an additional regulatory mechanism may be involved. NADP+-GDH seemed to be involved in nitrogen assimilation due to a constitutive aminating activity. The deaminating reaction, however was observed to change in response to varying ammonium concentrations which suggests that NADP+-GDH is also regulated in response to nitrogen availability. The regulation of NADP+-GDH activity was not reflected at the level of gene transcription thereby implicating post-transcriptional modification as a regulatory mechanism in response to nitrogen availability.
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Affiliation(s)
- Catriona J Harper
- DST/NRF Centre of Excellence for Biomedical TB Research, Department of Molecular Biology and Human Genetics, Faculty of Health Sciences, University of Stellenbosch, Tygerberg, South Africa.
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Cook GM, Berney M, Gebhard S, Heinemann M, Cox RA, Danilchanka O, Niederweis M. Physiology of mycobacteria. Adv Microb Physiol 2009; 55:81-182, 318-9. [PMID: 19573696 DOI: 10.1016/s0065-2911(09)05502-7] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Mycobacterium tuberculosis is a prototrophic, metabolically flexible bacterium that has achieved a spread in the human population that is unmatched by any other bacterial pathogen. The success of M. tuberculosis as a pathogen can be attributed to its extraordinary stealth and capacity to adapt to environmental changes throughout the course of infection. These changes include: nutrient deprivation, hypoxia, various exogenous stress conditions and, in the case of the pathogenic species, the intraphagosomal environment. Knowledge of the physiology of M. tuberculosis during this process has been limited by the slow growth of the bacterium in the laboratory and other technical problems such as cell aggregation. Advances in genomics and molecular methods to analyze the M. tuberculosis genome have revealed that adaptive changes are mediated by complex regulatory networks and signals, resulting in temporal gene expression coupled to metabolic and energetic changes. An important goal for bacterial physiologists will be to elucidate the physiology of M. tuberculosis during the transition between the diverse conditions encountered by M. tuberculosis. This review covers the growth of the mycobacterial cell and how environmental stimuli are sensed by this bacterium. Adaptation to different environments is described from the viewpoint of nutrient acquisition, energy generation, and regulation. To gain quantitative understanding of mycobacterial physiology will require a systems biology approach and recent efforts in this area are discussed.
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Affiliation(s)
- Gregory M Cook
- Department of Microbiology and Immunology, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand
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25
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Nitrogen control in Mycobacterium smegmatis: nitrogen-dependent expression of ammonium transport and assimilation proteins depends on the OmpR-type regulator GlnR. J Bacteriol 2008; 190:7108-16. [PMID: 18689485 DOI: 10.1128/jb.00855-08] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The effect of nitrogen regulation on the level of transcriptional control has been investigated in a variety of bacteria, such as Bacillus subtilis, Corynebacterium glutamicum, Escherichia coli, and Streptomyces coelicolor; however, until now there have been no data for mycobacteria. In this study, we found that the OmpR-type regulator protein GlnR controls nitrogen-dependent transcription regulation in Mycobacterium smegmatis. Based on RNA hybridization experiments with a wild-type strain and a corresponding mutant strain, real-time reverse transcription-PCR analyses, and DNA binding studies using cell extract and purified protein, the glnA (msmeg_4290) gene, which codes for glutamine synthetase, and the amtB (msmeg_2425) and amt1 (msmeg_6259) genes, which encode ammonium permeases, are controlled by GlnR. Furthermore, since glnK (msmeg_2426), encoding a PII-type signal transduction protein, and glnD (msmeg_2427), coding for a putative uridylyltransferase, are in an operon together with amtB, these genes are part of the GlnR regulon as well. The GlnR protein binds specifically to the corresponding promoter sequences and functions as an activator of transcription when cells are subjected to nitrogen starvation.
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