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Jiang F, Yang Y, Mao Z, Cai W, Li G. ArcA positively regulates the expression of virulence genes and contributes to virulence of porcine Shiga toxin-producing enterotoxigenic Escherichia coli. Microbiol Spectr 2023; 11:e0152523. [PMID: 37916813 PMCID: PMC10714933 DOI: 10.1128/spectrum.01525-23] [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: 04/12/2023] [Accepted: 10/09/2023] [Indexed: 11/03/2023] Open
Abstract
IMPORTANCE Enterotoxigenic Escherichia coli (ETEC) cause severe diarrhea in humans and animals, leading to death and huge economic loss worldwide. Thus, elucidation of ETEC's pathogenic mechanisms will provide powerful data for the discovery of drugs serving as prevention or therapeutics against ETEC-caused diarrheal diseases. Here, we report that ArcA plays an essential role in the pathogenicity and virulence regulation in ETEC by positively regulating the expression of several key virulence factors including F18 fimbriae, heat-labile and heat-stable toxins, Shiga toxin 2e, and hemolysin, under microaerobic conditions and in vivo. Moreover, we found that positive regulation of several virulence genes by ArcA requires a global repressor H-NS (histone-like nucleoid structuring), implying that ArcA may exert positive effects by antagonizing H-NS. Collectively, our data established a key role for ArcA in the pathogenicity of porcine ETEC and ETEC strains isolated from human infections. Moreover, our work reveals another layer of regulation in relation to oxygen control of virulence factors in ETEC.
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Affiliation(s)
- Fengwei Jiang
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, Iowa, USA
| | - Yan Yang
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Zhao Mao
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Wentong Cai
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Ganwu Li
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, Iowa, USA
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2
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Das S, Kim GW, Lee JG, Bhuiyan MSI, Kim PJ. Silicate fertilization improves microbial functional potentials for stress tolerance in arsenic-enriched rice cropping systems. JOURNAL OF HAZARDOUS MATERIALS 2021; 417:125953. [PMID: 33984783 DOI: 10.1016/j.jhazmat.2021.125953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 04/20/2021] [Accepted: 04/21/2021] [Indexed: 06/12/2023]
Abstract
The host plant and its rhizosphere microbiome are similarly exposed to abiotic stresses under arsenic (As)-enriched cropping systems. Since silicon (Si) fertilization is effective in alleviating As-induced stresses in plants, and plant-microbe interactions are tightly coupled, we hypothesized that Si-fertilization would improve soil microbial functional potentials to environmental stress tolerance, which was not yet studied. With the help of high throughput metagenome, microarray and analyzing plant impacts on soil microbiome and the environment, we tested the hypothesis in two geographically different rice (i.e., Japonica and Indica) grown on As-enriched soils. Silicate fertilization in rice grown on As-enriched soils altered rhizosphere bacterial communities and increased several commensal microorganisms and their genetic potential to tolerate oxidative stress, osmotic stress, oxygen limitation, nitrogen and phosphate limitation, heat and cold shock, and radiation stress. The stress resistant microbial communities shifted with the changes in rhizosphere nutrient flows and cumulative plant impacts on the soil environment. The study highlights a thus-far unexplored behavior of Si-fertilization to improve microbial stress resilience under As-laden cropping systems and opens up a promising avenue to further study how commonalities in plant-microbe signaling in response to Si-fertilization alleviates As-induced stresses in agro-systems.
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Affiliation(s)
- Suvendu Das
- Institute of Agriculture and Life Sciences, Gyeongsang National University, Jinju 660-701, South Korea
| | - Gil Won Kim
- Institute of Agriculture and Life Sciences, Gyeongsang National University, Jinju 660-701, South Korea
| | - Jeong Gu Lee
- Division of Applied Life Science, Gyeongsang National University, Jinju 660-701, South Korea
| | | | - Pil Joo Kim
- Institute of Agriculture and Life Sciences, Gyeongsang National University, Jinju 660-701, South Korea; Division of Applied Life Science, Gyeongsang National University, Jinju 660-701, South Korea.
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3
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Borisov VB, Siletsky SA, Paiardini A, Hoogewijs D, Forte E, Giuffrè A, Poole RK. Bacterial Oxidases of the Cytochrome bd Family: Redox Enzymes of Unique Structure, Function, and Utility As Drug Targets. Antioxid Redox Signal 2021; 34:1280-1318. [PMID: 32924537 PMCID: PMC8112716 DOI: 10.1089/ars.2020.8039] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 09/01/2020] [Accepted: 09/02/2020] [Indexed: 12/23/2022]
Abstract
Significance: Cytochrome bd is a ubiquinol:oxygen oxidoreductase of many prokaryotic respiratory chains with a unique structure and functional characteristics. Its primary role is to couple the reduction of molecular oxygen, even at submicromolar concentrations, to water with the generation of a proton motive force used for adenosine triphosphate production. Cytochrome bd is found in many bacterial pathogens and, surprisingly, in bacteria formally denoted as anaerobes. It endows bacteria with resistance to various stressors and is a potential drug target. Recent Advances: We summarize recent advances in the biochemistry, structure, and physiological functions of cytochrome bd in the light of exciting new three-dimensional structures of the oxidase. The newly discovered roles of cytochrome bd in contributing to bacterial protection against hydrogen peroxide, nitric oxide, peroxynitrite, and hydrogen sulfide are assessed. Critical Issues: Fundamental questions remain regarding the precise delineation of electron flow within this multihaem oxidase and how the extraordinarily high affinity for oxygen is accomplished, while endowing bacteria with resistance to other small ligands. Future Directions: It is clear that cytochrome bd is unique in its ability to confer resistance to toxic small molecules, a property that is significant for understanding the propensity of pathogens to possess this oxidase. Since cytochrome bd is a uniquely bacterial enzyme, future research should focus on harnessing fundamental knowledge of its structure and function to the development of novel and effective antibacterial agents.
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Affiliation(s)
- Vitaliy B. Borisov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation
| | - Sergey A. Siletsky
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation
| | | | - David Hoogewijs
- Department of Medicine/Physiology, University of Fribourg, Fribourg, Switzerland
| | - Elena Forte
- Department of Biochemical Sciences, Sapienza University of Rome, Rome, Italy
| | | | - Robert K. Poole
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield, United Kingdom
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4
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Mejía-Almonte C, Busby SJW, Wade JT, van Helden J, Arkin AP, Stormo GD, Eilbeck K, Palsson BO, Galagan JE, Collado-Vides J. Redefining fundamental concepts of transcription initiation in bacteria. Nat Rev Genet 2020; 21:699-714. [PMID: 32665585 PMCID: PMC7990032 DOI: 10.1038/s41576-020-0254-8] [Citation(s) in RCA: 77] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/29/2020] [Indexed: 12/15/2022]
Abstract
Despite enormous progress in understanding the fundamentals of bacterial gene regulation, our knowledge remains limited when compared with the number of bacterial genomes and regulatory systems to be discovered. Derived from a small number of initial studies, classic definitions for concepts of gene regulation have evolved as the number of characterized promoters has increased. Together with discoveries made using new technologies, this knowledge has led to revised generalizations and principles. In this Expert Recommendation, we suggest precise, updated definitions that support a logical, consistent conceptual framework of bacterial gene regulation, focusing on transcription initiation. The resulting concepts can be formalized by ontologies for computational modelling, laying the foundation for improved bioinformatics tools, knowledge-based resources and scientific communication. Thus, this work will help researchers construct better predictive models, with different formalisms, that will be useful in engineering, synthetic biology, microbiology and genetics.
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Affiliation(s)
- Citlalli Mejía-Almonte
- Programa de Genómica Computacional, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Morelos, Cuernavaca, México
| | | | - Joseph T Wade
- Division of Genetics, Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | - Jacques van Helden
- Aix-Marseille University, INSERM UMR S 1090, Theory and Approaches of Genome Complexity (TAGC), Marseille, France
- CNRS, Institut Français de Bioinformatique, IFB-core, UMS 3601, Evry, France
| | - Adam P Arkin
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA, USA
| | - Gary D Stormo
- Department of Genetics, Washington University School of Medicine, St Louis, MO, USA
| | - Karen Eilbeck
- Department of Biomedical Informatics, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Bernhard O Palsson
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, USA
| | - James E Galagan
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Julio Collado-Vides
- Programa de Genómica Computacional, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Morelos, Cuernavaca, México.
- Department of Biomedical Engineering, Boston University, Boston, MA, USA.
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5
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Zeldes BM, Loder AJ, Counts JA, Haque M, Widney KA, Keller LM, Albers S, Kelly RM. Determinants of sulphur chemolithoautotrophy in the extremely thermoacidophilicSulfolobales. Environ Microbiol 2019; 21:3696-3710. [DOI: 10.1111/1462-2920.14712] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 06/04/2019] [Accepted: 06/09/2019] [Indexed: 11/29/2022]
Affiliation(s)
- Benjamin M. Zeldes
- Department of Chemical and Biomolecular EngineeringNorth Carolina State University Raleigh NC 27695‐7905 USA
| | - Andrew J. Loder
- Department of Chemical and Biomolecular EngineeringNorth Carolina State University Raleigh NC 27695‐7905 USA
| | - James A. Counts
- Department of Chemical and Biomolecular EngineeringNorth Carolina State University Raleigh NC 27695‐7905 USA
| | - Mashkurul Haque
- Department of Chemical and Biomolecular EngineeringNorth Carolina State University Raleigh NC 27695‐7905 USA
| | - Karl A. Widney
- Department of Chemical and Biomolecular EngineeringNorth Carolina State University Raleigh NC 27695‐7905 USA
| | - Lisa M. Keller
- Department of Chemical and Biomolecular EngineeringNorth Carolina State University Raleigh NC 27695‐7905 USA
| | - Sonja‐Verena Albers
- Institute of Biology II – MicrobiologyUniversity of Freiburg Freiburg Germany
| | - Robert M. Kelly
- Department of Chemical and Biomolecular EngineeringNorth Carolina State University Raleigh NC 27695‐7905 USA
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6
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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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7
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Matsuoka Y, Kurata H. Modeling and simulation of the redox regulation of the metabolism in Escherichia coli at different oxygen concentrations. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:183. [PMID: 28725263 PMCID: PMC5512849 DOI: 10.1186/s13068-017-0867-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 07/05/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND Microbial production of biofuels and biochemicals from renewable feedstocks has received considerable recent attention from environmental protection and energy production perspectives. Many biofuels and biochemicals are produced by fermentation under oxygen-limited conditions following initiation of aerobic cultivation to enhance the cell growth rate. Thus, it is of significant interest to investigate the effect of dissolved oxygen concentration on redox regulation in Escherichia coli, a particularly popular cellular factory due to its high growth rate and well-characterized physiology. For this, the systems biology approach such as modeling is powerful for the analysis of the metabolism and for the design of microbial cellular factories. RESULTS Here, we developed a kinetic model that describes the dynamics of fermentation by taking into account transcription factors such as ArcA/B and Fnr, respiratory chain reactions and fermentative pathways, and catabolite regulation. The hallmark of the kinetic model is its ability to predict the dynamics of metabolism at different dissolved oxygen levels and facilitate the rational design of cultivation methods. The kinetic model was verified based on the experimental data for a wild-type E. coli strain. The model reasonably predicted the metabolic characteristics and molecular mechanisms of fnr and arcA gene-knockout mutants. Moreover, an aerobic-microaerobic dual-phase cultivation method for lactate production in a pfl-knockout mutant exhibited promising yield and productivity. CONCLUSIONS It is quite important to understand metabolic regulation mechanisms from both scientific and engineering points of view. In particular, redox regulation in response to oxygen limitation is critically important in the practical production of biofuel and biochemical compounds. The developed model can thus be used as a platform for designing microbial factories to produce a variety of biofuels and biochemicals.
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Affiliation(s)
- Yu Matsuoka
- Department of Bioscience and Bioinformatics, Kyushu Institute of Technology, 680-4 Kawazu, Iizuka, Fukuoka, 820-8502 Japan
| | - Hiroyuki Kurata
- Department of Bioscience and Bioinformatics, Kyushu Institute of Technology, 680-4 Kawazu, Iizuka, Fukuoka, 820-8502 Japan
- Biomedical Informatics R&D Center, Kyushu Institute of Technology, 680-4 Kawazu, Iizuka, Fukuoka, 820-8502 Japan
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8
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von Wulffen J, Ulmer A, Jäger G, Sawodny O, Feuer R. Rapid Sampling of Escherichia coli After Changing Oxygen Conditions Reveals Transcriptional Dynamics. Genes (Basel) 2017; 8:genes8030090. [PMID: 28264512 PMCID: PMC5368694 DOI: 10.3390/genes8030090] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 02/10/2017] [Accepted: 02/20/2017] [Indexed: 12/21/2022] Open
Abstract
Escherichia coli is able to shift between anaerobic and aerobic metabolism by adapting its gene expression, e.g., of metabolic genes, to the new environment. The dynamics of gene expression that result from environmental shifts are limited, amongst others, by the time needed for regulation and transcription elongation. In this study, we examined gene expression dynamics after an anaerobic-to-aerobic shift on a short time scale (0.5, 1, 2, 5, and 10 min) by RNA sequencing with emphasis on delay times and transcriptional elongation rates (TER). Transient expression patterns and timing of differential expression, characterized by delay and elongation, were identified as key features of the dataset. Gene ontology enrichment analysis revealed early upregulation of respiratory and iron-related gene sets. We inferred specific TERs of 89 operons with a mean TER of 42.0 nt/s and mean delay time of 22.4 s. TERs correlate with sequence features, such as codon bias, whereas delay times correlate with the involvement of regulators. The presented data illustrate that at very short times after a shift in oxygenation, extensional changes of the transcriptome, such as temporary responses, can be observed. Besides regulation, TERs contribute to the dynamics of gene expression.
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Affiliation(s)
- Joachim von Wulffen
- Institute for System Dynamics, University of Stuttgart, Keplerstraße 7, 70174 Stuttgart, Germany.
| | - Andreas Ulmer
- Institute for System Dynamics, University of Stuttgart, Keplerstraße 7, 70174 Stuttgart, Germany.
| | - Günter Jäger
- Insitute of Medical Genetics and Applied Genomics, University of Tübingen, Geschwister-Scholl-Platz, 72074 Tübingen, Germany.
| | - Oliver Sawodny
- Institute for System Dynamics, University of Stuttgart, Keplerstraße 7, 70174 Stuttgart, Germany.
| | - Ronny Feuer
- Institute for System Dynamics, University of Stuttgart, Keplerstraße 7, 70174 Stuttgart, Germany.
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9
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Wareham LK, Begg R, Jesse HE, Van Beilen JWA, Ali S, Svistunenko D, McLean S, Hellingwerf KJ, Sanguinetti G, Poole RK. Carbon Monoxide Gas Is Not Inert, but Global, in Its Consequences for Bacterial Gene Expression, Iron Acquisition, and Antibiotic Resistance. Antioxid Redox Signal 2016; 24:1013-28. [PMID: 26907100 PMCID: PMC4921903 DOI: 10.1089/ars.2015.6501] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AIMS Carbon monoxide is a respiratory poison and gaseous signaling molecule. Although CO-releasing molecules (CORMs) deliver CO with temporal and spatial specificity in mammals, and are proven antimicrobial agents, we do not understand the modes of CO toxicity. Our aim was to explore the impact of CO gas per se, without intervention of CORMs, on bacterial physiology and gene expression. RESULTS We used tightly controlled chemostat conditions and integrated transcriptomic datasets with statistical modeling to reveal the global effects of CO. CO is known to inhibit bacterial respiration, and we found expression of genes encoding energy-transducing pathways to be significantly affected via the global regulators, Fnr, Arc, and PdhR. Aerobically, ArcA-the response regulator-is transiently phosphorylated and pyruvate accumulates, mimicking anaerobiosis. Genes implicated in iron acquisition, and the metabolism of sulfur amino acids and arginine, are all perturbed. The global iron-related changes, confirmed by modulation of activity of the transcription factor Fur, may underlie enhanced siderophore excretion, diminished intracellular iron pools, and the sensitivity of CO-challenged bacteria to metal chelators. Although CO gas (unlike H2S and NO) offers little protection from antibiotics, a ruthenium CORM is a potent adjuvant of antibiotic activity. INNOVATION This is the first detailed exploration of global bacterial responses to CO, revealing unexpected targets with implications for employing CORMs therapeutically. CONCLUSION This work reveals the complexity of bacterial responses to CO and provides a basis for understanding the impacts of CO from CORMs, heme oxygenase activity, or environmental sources. Antioxid. Redox Signal. 24, 1013-1028.
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Affiliation(s)
- Lauren K Wareham
- 1 Department of Molecular Biology and Biotechnology, The University of Sheffield , Sheffield, United Kingdom
| | - Ronald Begg
- 2 School of Informatics, The University of Edinburgh , Edinburgh, United Kingdom
| | - Helen E Jesse
- 1 Department of Molecular Biology and Biotechnology, The University of Sheffield , Sheffield, United Kingdom
| | - Johan W A Van Beilen
- 3 Molecular Microbial Physiology, Swammerdam Institute for Life Sciences, University of Amsterdam , Amsterdam, The Netherlands
| | - Salar Ali
- 1 Department of Molecular Biology and Biotechnology, The University of Sheffield , Sheffield, United Kingdom
| | - Dimitri Svistunenko
- 4 Biomedical EPR Facility, School of Biological Sciences, University of Essex , Colchester, United Kingdom
| | - Samantha McLean
- 1 Department of Molecular Biology and Biotechnology, The University of Sheffield , Sheffield, United Kingdom
| | - Klaas J Hellingwerf
- 3 Molecular Microbial Physiology, Swammerdam Institute for Life Sciences, University of Amsterdam , Amsterdam, The Netherlands
| | - Guido Sanguinetti
- 2 School of Informatics, The University of Edinburgh , Edinburgh, United Kingdom
| | - Robert K Poole
- 1 Department of Molecular Biology and Biotechnology, The University of Sheffield , Sheffield, United Kingdom
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10
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Xiao M, Lai Y, Sun J, Chen G, Yan A. Transcriptional Regulation of the Outer Membrane Porin Gene ompW Reveals its Physiological Role during the Transition from the Aerobic to the Anaerobic Lifestyle of Escherichia coli. Front Microbiol 2016; 7:799. [PMID: 27303386 PMCID: PMC4886647 DOI: 10.3389/fmicb.2016.00799] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 05/11/2016] [Indexed: 11/13/2022] Open
Abstract
Understanding bacterial physiology relies on elucidating the regulatory mechanisms and cellular functions of those differentially expressed genes in response to environmental changes. A widespread Gram-negative bacterial outer membrane protein OmpW has been implicated in the adaptation to stresses in various species. It is recently found to be present in the regulon of the global anaerobic transcription factor FNR and ArcA in Escherichia coli. However, little is known about the physiological implications of this regulatory disposition. In this study, we demonstrate that transcription of ompW is indeed mediated by a series of global regulators involved in the anaerobiosis of E. coli. We show that FNR can both activate and repress the expression of ompW through its direct binding to two distinctive sites, -81.5 and -126.5 bp respectively, on ompW promoter. ArcA also participates in repression of ompW under anaerobic condition, but in an FNR dependent manner. Additionally, ompW is also subject to the regulation by CRP and NarL which senses the availability and types of carbon sources and respiration electron acceptors in the environment respectively, implying a role of OmpW in the carbon and energy metabolism of E. coli during its anaerobic adaptation. Molecular docking reveals that OmpW can bind fumarate, an alternative electron acceptor in anaerobic respiration, with sufficient affinity. Moreover, supplement of fumarate or succinate which belongs to the C4-dicarboxylates family of metabolite, to E. coli culture rescues OmpW-mediated colicin S4 killing. Taken together, we propose that OmpW is involved in anaerobic carbon and energy metabolism to mediate the transition from aerobic to anaerobic lifestyle in E. coli.
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Affiliation(s)
- Minfeng Xiao
- School of Biological Sciences, The University of Hong Kong Hong Kong, China
| | - Yong Lai
- School of Biological Sciences, The University of Hong Kong Hong Kong, China
| | - Jian Sun
- Department of Chemistry, The University of Hong Kong Hong Kong, China
| | - Guanhua Chen
- Department of Chemistry, The University of Hong Kong Hong Kong, China
| | - Aixin Yan
- School of Biological Sciences, The University of Hong Kong Hong Kong, China
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11
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Surmann K, Ćudić E, Hammer E, Hunke S. Molecular and proteome analyses highlight the importance of the Cpx envelope stress system for acid stress and cell wall stability in Escherichia coli. Microbiologyopen 2016; 5:582-96. [PMID: 27039284 PMCID: PMC4985592 DOI: 10.1002/mbo3.353] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 02/10/2016] [Accepted: 02/15/2016] [Indexed: 01/24/2023] Open
Abstract
Two‐component systems (TCS) play a pivotal role for bacteria in stress regulation and adaptation. However, it is not well understood how these systems are modulated to meet bacterial demands. Especially, for those TCS using an accessory protein to integrate additional signals, no data concerning the role of the accessory proteins within the coordination of the response is available. The Cpx envelope stress two‐component system, composed of the sensor kinase CpxA and the response regulator CpxR, is orchestrated by the periplasmic protein CpxP which detects misfolded envelope proteins and inhibits the Cpx system in unstressed cells. Using selected reaction monitoring, we observed that the amount of CpxA and CpxR, as well as their stoichiometry, are only marginally affected, but that a 10‐fold excess of CpxP over CpxA is needed to switch off the Cpx system. Moreover, the relative quantification of the proteome identified not only acid stress response as a new indirect target of the Cpx system, but also suggests a general function of the Cpx system for cell wall stability.
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Affiliation(s)
- Kristin Surmann
- Department of Functional Genomics, Interfaculty Institute of Genetics and Functional Genomics, University Medicine Greifswald, Friedrich-Ludwig-Jahn-Straße 15A, Greifswald, 17475, Germany
| | - Emina Ćudić
- FB 5 Microbiology, Department of Biology/Chemistry, University Osnabrück, Barbarastraße 11, Osnabrück, 49076,, Germany
| | - Elke Hammer
- Department of Functional Genomics, Interfaculty Institute of Genetics and Functional Genomics, University Medicine Greifswald, Friedrich-Ludwig-Jahn-Straße 15A, Greifswald, 17475, Germany
| | - Sabine Hunke
- FB 5 Microbiology, Department of Biology/Chemistry, University Osnabrück, Barbarastraße 11, Osnabrück, 49076,, Germany
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12
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Gerganova V, Maurer S, Stoliar L, Japaridze A, Dietler G, Nasser W, Kutateladze T, Travers A, Muskhelishvili G. Upstream binding of idling RNA polymerase modulates transcription initiation from a nearby promoter. J Biol Chem 2015; 290:8095-109. [PMID: 25648898 DOI: 10.1074/jbc.m114.628131] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The bacterial gene regulatory regions often demonstrate distinctly organized arrays of RNA polymerase binding sites of ill-defined function. Previously we observed a module of closely spaced polymerase binding sites upstream of the canonical promoter of the Escherichia coli fis operon. FIS is an abundant nucleoid-associated protein involved in adjusting the chromosomal DNA topology to changing cellular physiology. Here we show that simultaneous binding of the polymerase at the canonical fis promoter and an upstream transcriptionally inactive site stabilizes a RNAP oligomeric complex in vitro. We further show that modulation of the upstream binding of RNA polymerase affects the fis promoter activity both in vivo and in vitro. The effect of the upstream RNA polymerase binding on the fis promoter activity depends on the spatial arrangement of polymerase binding sites and DNA supercoiling. Our data suggest that a specific DNA geometry of the nucleoprotein complex stabilized on concomitant binding of RNA polymerase molecules at the fis promoter and the upstream region acts as a topological device regulating the fis transcription. We propose that transcriptionally inactive RNA polymerase molecules can act as accessory factors regulating the transcription initiation from a nearby promoter.
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Affiliation(s)
- Veneta Gerganova
- From the School of Engineering and Science, Jacobs University Bremen, Campus Ring 1, D-28759 Bremen, Germany
| | - Sebastian Maurer
- From the School of Engineering and Science, Jacobs University Bremen, Campus Ring 1, D-28759 Bremen, Germany
| | - Liubov Stoliar
- From the School of Engineering and Science, Jacobs University Bremen, Campus Ring 1, D-28759 Bremen, Germany
| | - Aleksandre Japaridze
- the Laboratory of the Physics of Living Matter, EPFL, CH-1015 Lausanne, Switzerland
| | - Giovanni Dietler
- the Laboratory of the Physics of Living Matter, EPFL, CH-1015 Lausanne, Switzerland
| | - William Nasser
- the UMR5240 CNRS/INSA/UCB, Université de Lyon, F-69003, INSA-Lyon, Villeurbanne, F-69621, France
| | - Tamara Kutateladze
- the Ivane Beritashvili Centre of Experimental Biomedicine, Gotua str.14, Tbilisi, Georgia, and
| | - Andrew Travers
- the MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 QH, United Kingdom
| | - Georgi Muskhelishvili
- From the School of Engineering and Science, Jacobs University Bremen, Campus Ring 1, D-28759 Bremen, Germany,
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Holyoake LV, Poole RK, Shepherd M. The CydDC Family of Transporters and Their Roles in Oxidase Assembly and Homeostasis. Adv Microb Physiol 2015. [PMID: 26210105 DOI: 10.1016/bs.ampbs.2015.04.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The CydDC complex of Escherichia coli is a heterodimeric ATP-binding cassette type transporter (ABC transporter) that exports the thiol-containing redox-active molecules cysteine and glutathione. These reductants are thought to aid redox homeostasis of the periplasm, permitting correct disulphide folding of periplasmic and secreted proteins. Loss of CydDC results in the periplasm becoming more oxidising and abolishes the assembly of functional bd-type respiratory oxidases that couple the oxidation of ubiquinol to the reduction of oxygen to water. In addition, CydDC-mediated redox control is important for haem ligation during cytochrome c assembly. Given the diverse roles for CydDC in redox homeostasis, respiratory metabolism and the maturation of virulence factors, this ABC transporter is an intriguing system for researchers interested in both the physiology of redox perturbations and the role of low-molecular-weight thiols during infection.
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14
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Park DM, Akhtar MS, Ansari AZ, Landick R, Kiley PJ. The bacterial response regulator ArcA uses a diverse binding site architecture to regulate carbon oxidation globally. PLoS Genet 2013; 9:e1003839. [PMID: 24146625 PMCID: PMC3798270 DOI: 10.1371/journal.pgen.1003839] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Accepted: 08/13/2013] [Indexed: 12/02/2022] Open
Abstract
Despite the importance of maintaining redox homeostasis for cellular viability, how cells control redox balance globally is poorly understood. Here we provide new mechanistic insight into how the balance between reduced and oxidized electron carriers is regulated at the level of gene expression by mapping the regulon of the response regulator ArcA from Escherichia coli, which responds to the quinone/quinol redox couple via its membrane-bound sensor kinase, ArcB. Our genome-wide analysis reveals that ArcA reprograms metabolism under anaerobic conditions such that carbon oxidation pathways that recycle redox carriers via respiration are transcriptionally repressed by ArcA. We propose that this strategy favors use of catabolic pathways that recycle redox carriers via fermentation akin to lactate production in mammalian cells. Unexpectedly, bioinformatic analysis of the sequences bound by ArcA in ChIP-seq revealed that most ArcA binding sites contain additional direct repeat elements beyond the two required for binding an ArcA dimer. DNase I footprinting assays suggest that non-canonical arrangements of cis-regulatory modules dictate both the length and concentration-sensitive occupancy of DNA sites. We propose that this plasticity in ArcA binding site architecture provides both an efficient means of encoding binding sites for ArcA, σ70-RNAP and perhaps other transcription factors within the same narrow sequence space and an effective mechanism for global control of carbon metabolism to maintain redox homeostasis. The cofactor NAD+ plays a central role in energy conservation pathways, shuttling electrons from the oxidation of growth substrates to respiratory or fermentative pathways. To sustain catabolism and cellular ATP demand, an appropriate balance between the reduced and oxidized forms of NAD+ must be maintained. Our genome-scale analysis of the transcription factor ArcA provides insight into how this process is transcriptionally regulated in E. coli in the absence of O2. We found that ArcA mediates a previously unrealized comprehensive transcriptional repression of genes encoding proteins associated with oxidation of non-fermentable carbon sources. Through the repression of these pathways, oxidized NAD+ is effectively preserved for fermentation pathways, facilitating energy conservation and preserving a balance between the oxidized and reduced forms of NAD+ in the absence of aerobic respiration. In addition, we found that the majority of ArcA binding sites contain additional sequence elements beyond that required for binding of an ArcA dimer, providing novel insight into how ArcA and other members of the largest class of two component system-response regulators (OmpR/PhoB family) may achieve global regulation of gene expression.
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Affiliation(s)
- Dan M. Park
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Md. Sohail Akhtar
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Aseem Z. Ansari
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Robert Landick
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Department of Bacteriology; University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Patricia J. Kiley
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- * E-mail:
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15
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Zhou A, He Z, Qin Y, Lu Z, Deng Y, Tu Q, Hemme CL, Van Nostrand JD, Wu L, Hazen TC, Arkin AP, Zhou J. StressChip as a high-throughput tool for assessing microbial community responses to environmental stresses. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:9841-9849. [PMID: 23889170 DOI: 10.1021/es4018656] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Microbial community responses to environmental stresses are critical for microbial growth, survival, and adaptation. To fill major gaps in our ability to discern the influence of environmental changes on microbial communities from engineered and natural environments, a functional gene-based microarray, termed StressChip, has been developed. First, 46 functional genes involved in microbial responses to environmental stresses such as changes to temperature, osmolarity, oxidative status, nutrient limitation, or general stress response were selected and curated. A total of 22,855 probes were designed, covering 79,628 coding sequences from 985 bacterial, 76 archaeal, and 59 eukaryotic species/strains. Probe specificity was computationally verified. Second, the usefulness of functional genes as indicators of stress response was examined by surveying their distribution in metagenome data sets. The abundance of individual stress response genes is consistent with expected distributions based on respective habitats. Third, the StressChip was used to analyze marine microbial communities from the Deepwater Horizon oil spill. That functional stress response genes were detected in higher abundance (p < 0.05) in oil plume compared to nonplume samples indicated shifts in community composition and structure, consistent with previous results. In summary, StressChip provides a new tool for accessing microbial community functional structure and responses to environmental changes.
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Affiliation(s)
- Aifen Zhou
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, University of Oklahoma , Norman, Oklahoma 73019, United States
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16
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Deng Z, Shan Y, Pan Q, Gao X, Yan A. Anaerobic expression of the gadE-mdtEF multidrug efflux operon is primarily regulated by the two-component system ArcBA through antagonizing the H-NS mediated repression. Front Microbiol 2013; 4:194. [PMID: 23874328 PMCID: PMC3708157 DOI: 10.3389/fmicb.2013.00194] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Accepted: 06/24/2013] [Indexed: 12/28/2022] Open
Abstract
The gadE-mdtEF operon encodes a central acid resistance regulator GadE and two multidrug efflux proteins MdtEF. Although transcriptional regulation of gadE in the context of acid resistance under the aerobic growth environment of Escherichia coli has been extensively studied, regulation of the operon under the physiologically relevant environment of anaerobic growth and its effect on the expression of the multidrug efflux proteins MdtEF in the operon has not been disclosed. Our previous study revealed that anaerobic induction of the operon was dependent on ArcA, the response regulator of the ArcBA two-component system, in the M9 glucose minimal medium. However, the detailed regulatory mechanism remains unknown. In this study, we showed that anaerobic activation of mdtEF was driven by the 798 bp unusually long gadE promoter. Deletion of evgA, ydeO, rpoS, and gadX which has been shown to activate the gadE expression during acid stresses under aerobic condition did not have a significant effect on the anaerobic activation of the operon. Rather, anaerobic activation of the operon was largely dependent on the global regulator ArcA and a GTPase MnmE. Under aerobic condition, transcription of gadE was repressed by the global DNA silencer H-NS in M9 minimal medium. Interestingly, under anaerobic condition, while ΔarcA almost completely abolished transcription of gadE-mdtEF, further deletion of hns in ΔarcA mutant restored the transcription of the full-length PgadE-lacZ, and P1- and P3-lacZ fusions, suggesting an antagonistic effect of ArcA on the H-NS mediated repression. Taken together, we conclude that the anaerobic activation of the gadE-mdtEF was primarily mediated by the two-component system ArcBA through antagonizing the H-NS mediated repression.
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Affiliation(s)
- Ziqing Deng
- School of Biological Sciences, The University of Hong Kong Hong Kong, China
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17
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Myers KS, Yan H, Ong IM, Chung D, Liang K, Tran F, Keleş S, Landick R, Kiley PJ. Genome-scale analysis of escherichia coli FNR reveals complex features of transcription factor binding. PLoS Genet 2013; 9:e1003565. [PMID: 23818864 PMCID: PMC3688515 DOI: 10.1371/journal.pgen.1003565] [Citation(s) in RCA: 132] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Accepted: 04/29/2013] [Indexed: 01/05/2023] Open
Abstract
FNR is a well-studied global regulator of anaerobiosis, which is widely conserved across bacteria. Despite the importance of FNR and anaerobiosis in microbial lifestyles, the factors that influence its function on a genome-wide scale are poorly understood. Here, we report a functional genomic analysis of FNR action. We find that FNR occupancy at many target sites is strongly influenced by nucleoid-associated proteins (NAPs) that restrict access to many FNR binding sites. At a genome-wide level, only a subset of predicted FNR binding sites were bound under anaerobic fermentative conditions and many appeared to be masked by the NAPs H-NS, IHF and Fis. Similar assays in cells lacking H-NS and its paralog StpA showed increased FNR occupancy at sites bound by H-NS in WT strains, indicating that large regions of the genome are not readily accessible for FNR binding. Genome accessibility may also explain our finding that genome-wide FNR occupancy did not correlate with the match to consensus at binding sites, suggesting that significant variation in ChIP signal was attributable to cross-linking or immunoprecipitation efficiency rather than differences in binding affinities for FNR sites. Correlation of FNR ChIP-seq peaks with transcriptomic data showed that less than half of the FNR-regulated operons could be attributed to direct FNR binding. Conversely, FNR bound some promoters without regulating expression presumably requiring changes in activity of condition-specific transcription factors. Such combinatorial regulation may allow Escherichia coli to respond rapidly to environmental changes and confer an ecological advantage in the anaerobic but nutrient-fluctuating environment of the mammalian gut. Regulation of gene expression by transcription factors (TFs) is key to adaptation to environmental changes. Our comprehensive, genome-scale analysis of a prototypical global TF, the anaerobic regulator FNR from Escherichia coli, leads to several novel and unanticipated insights into the influences on FNR binding genome-wide and the complex structure of bacterial regulons. We found that binding of NAPs restricts FNR binding at a subset of sites, suggesting that the bacterial genome is not freely accessible for FNR binding. Our finding that less than half of the predicted FNR binding sites were occupied in vivo further challenges the utility of using bioinformatic searches alone to predict regulon structure, reinforcing the need for experimental determination of TF binding. By correlating the occupancy data with transcriptomic data, we confirm that FNR serves as a global signal of anaerobiosis but expression of some operons in the FNR regulon require other regulators sensitive to alternative environmental stimuli. Thus, FNR binding and regulation appear to depend on both the nucleoprotein structure of the chromosome and on combinatorial binding of FNR with other regulators. Both of these phenomena are typical of TF binding in eukaryotes; our results establish that they are also features of bacterial TF binding.
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Affiliation(s)
- Kevin S. Myers
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Huihuang Yan
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Irene M. Ong
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Dongjun Chung
- Department of Statistics, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Kun Liang
- Department of Statistics, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Department of Biostatistics and Medical Informatics, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Frances Tran
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Sündüz Keleş
- Department of Statistics, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Department of Biostatistics and Medical Informatics, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Robert Landick
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- * E-mail: (RL); (PJK)
| | - Patricia J. Kiley
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- * E-mail: (RL); (PJK)
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18
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Fu H, Chen H, Wang J, Zhou G, Zhang H, Zhang L, Gao H. Crp-dependent cytochromebdoxidase confers nitrite resistance toShewanella oneidensis. Environ Microbiol 2013; 15:2198-212. [DOI: 10.1111/1462-2920.12091] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Accepted: 01/17/2013] [Indexed: 11/28/2022]
Affiliation(s)
- Huihui Fu
- Institute of Microbiology and College of Life Sciences; Zhejiang University; Hangzhou; Zhejiang; 310058; China
| | - Haijiang Chen
- Institute of Microbiology and College of Life Sciences; Zhejiang University; Hangzhou; Zhejiang; 310058; China
| | - Jixuan Wang
- Institute of Microbiology and College of Life Sciences; Zhejiang University; Hangzhou; Zhejiang; 310058; China
| | - Guangqi Zhou
- Institute of Microbiology and College of Life Sciences; Zhejiang University; Hangzhou; Zhejiang; 310058; China
| | | | - Lili Zhang
- College of Life Sciences; Tarim University; Alar; Xinjiang; 843300; China
| | - Haichun Gao
- Institute of Microbiology and College of Life Sciences; Zhejiang University; Hangzhou; Zhejiang; 310058; China
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19
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Hamamura N, Meneghin J, Reysenbach AL. Comparative community gene expression analysis of Aquificales-dominated geothermal springs. Environ Microbiol 2013; 15:1226-37. [PMID: 23279131 DOI: 10.1111/1462-2920.12061] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Revised: 11/01/2012] [Accepted: 11/25/2012] [Indexed: 11/29/2022]
Abstract
Members of Sulfurihydrogenibium are often observed as visible filamentous biomass in circumneutral hot springs and play roles in sulfur-cycling, hydrogen oxidation and iron mineralization. To gain insight into the ecophysiology of Sulfurihydrogenibium populations, we conducted preliminary metatranscriptomic analysis of three distinct thermal springs; Calcite Springs (YNP-CS) and Mammoth Springs (YNP-MHS) in Yellowstone National Park, USA, and Furnas Springs (AZ) in Azores, Portugal. Genes to which transcripts were assigned revealed commonly expressed functions among the sites, while several differences were also observed. All three sites, Sulfurihydrogenibium spp. dominate and are obtaining energy via metabolism of sulfur compounds under microaerophilic conditions. Cell motility was one of the expressed functions in two sites (YNP-CS and AZ) with slower stream flow rates and thicker well-formed biofilms. The transcripts from YNP-CS and -MHS exhibited varying levels of sequence divergence from the reference genomes and corresponding metagenomes, suggesting the presence of microdiversity among Sulfurihydrogenibium populations in situ. Conversely, the majority of the AZ transcripts were identical to the S. azorense genome. Our initial results show that the metatranscriptomes in these similar Aquificales-dominated communities can reveal community-level gene function in geochemically distinct thermal environments.
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Affiliation(s)
- Natsuko Hamamura
- Center for Marine Environmental Studies, Ehime University, Matsuyama, Ehime, 790-8577, Japan.
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20
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Sousa PMF, Videira MAM, Bohn A, Hood BL, Conrads TP, Goulao LF, Melo AMP. The aerobic respiratory chain of Escherichia coli: from genes to supercomplexes. MICROBIOLOGY-SGM 2012; 158:2408-2418. [PMID: 22700653 DOI: 10.1099/mic.0.056531-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In spite of the large number of reports on the aerobic respiratory chain of Escherichia coli, from gene transcription regulation to enzyme kinetics and structural studies, an integrative perspective of this pathway is yet to be produced. Here, a multi-level analysis of the aerobic respiratory chain of E. coli was performed to find correlations between gene transcription, enzyme activity, growth dynamics, and supercomplex formation and composition. The transcription level of all genes encoding the aerobic respiratory chain of E. coli varied significantly in response to bacterial growth. Coordinated expression patterns were observed between the genes encoding NADH : quinone oxidoreductase and complex I (NDH-1), alternative NADH : quinone oxidoreductase (NDH-2) and cytochrome bdI, and also between sdhA and appC, encoding succinate dehydrogenase and cytochrome bdII, respectively. In general, the rates of the respiratory chain activities increased from mid-exponential to late-stationary phase, with no significant further variation occurring until the mid-stationary phase. Multi-level correlations between gene transcription, enzyme activity and growth dynamics were also found in this study. The previously reported NADH dehydrogenase and formate : oxygen oxidoreductase supercomplexes of E. coli were already assembled at mid-exponential phase and remained throughout growth. A new succinate oxidase supercomplex composed of succinate dehydrogenase and cytochrome bdII was identified, in agreement with the suggestion provided by the coordinated transcription of sdhA and appC.
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Affiliation(s)
- Pedro M F Sousa
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República (EAN) 2780-157 Oeiras, Portugal.,Eco-Bio, Instituto de Investigação Científica Tropical, Av. da República (EAN) 2784-505 Oeiras, Portugal
| | - Marco A M Videira
- Eco-Bio, Instituto de Investigação Científica Tropical, Av. da República (EAN) 2784-505 Oeiras, Portugal
| | - Andreas Bohn
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República (EAN) 2780-157 Oeiras, Portugal
| | - Brian L Hood
- Gynecologic Cancer Center of Excellence, Women's Health Integrated Research Center at Inova Health System, Woodburn II, Suite 375, 3289 Woodburn Road, Annandale, VA 22003, USA
| | - Thomas P Conrads
- Gynecologic Cancer Center of Excellence, Women's Health Integrated Research Center at Inova Health System, Woodburn II, Suite 375, 3289 Woodburn Road, Annandale, VA 22003, USA
| | - Luis F Goulao
- Eco-Bio, Instituto de Investigação Científica Tropical, Av. da República (EAN) 2784-505 Oeiras, Portugal
| | - Ana M P Melo
- Eco-Bio, Instituto de Investigação Científica Tropical, Av. da República (EAN) 2784-505 Oeiras, Portugal
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21
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Bueno E, Mesa S, Bedmar EJ, Richardson DJ, Delgado MJ. Bacterial adaptation of respiration from oxic to microoxic and anoxic conditions: redox control. Antioxid Redox Signal 2012; 16:819-52. [PMID: 22098259 PMCID: PMC3283443 DOI: 10.1089/ars.2011.4051] [Citation(s) in RCA: 110] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Revised: 11/16/2011] [Accepted: 11/18/2011] [Indexed: 12/22/2022]
Abstract
Under a shortage of oxygen, bacterial growth can be faced mainly by two ATP-generating mechanisms: (i) by synthesis of specific high-affinity terminal oxidases that allow bacteria to use traces of oxygen or (ii) by utilizing other substrates as final electron acceptors such as nitrate, which can be reduced to dinitrogen gas through denitrification or to ammonium. This bacterial respiratory shift from oxic to microoxic and anoxic conditions requires a regulatory strategy which ensures that cells can sense and respond to changes in oxygen tension and to the availability of other electron acceptors. Bacteria can sense oxygen by direct interaction of this molecule with a membrane protein receptor (e.g., FixL) or by interaction with a cytoplasmic transcriptional factor (e.g., Fnr). A third type of oxygen perception is based on sensing changes in redox state of molecules within the cell. Redox-responsive regulatory systems (e.g., ArcBA, RegBA/PrrBA, RoxSR, RegSR, ActSR, ResDE, and Rex) integrate the response to multiple signals (e.g., ubiquinone, menaquinone, redox active cysteine, electron transport to terminal oxidases, and NAD/NADH) and activate or repress target genes to coordinate the adaptation of bacterial respiration from oxic to anoxic conditions. Here, we provide a compilation of the current knowledge about proteins and regulatory networks involved in the redox control of the respiratory adaptation of different bacterial species to microxic and anoxic environments.
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Affiliation(s)
- Emilio Bueno
- Estación Experimental del Zaidín, CSIC, Granada, Spain
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22
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Troxell B, Fink RC, Porwollik S, McClelland M, Hassan HM. The Fur regulon in anaerobically grown Salmonella enterica sv. Typhimurium: identification of new Fur targets. BMC Microbiol 2011; 11:236. [PMID: 22017966 PMCID: PMC3212961 DOI: 10.1186/1471-2180-11-236] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Accepted: 10/21/2011] [Indexed: 01/17/2023] Open
Abstract
Background The Ferric uptake regulator (Fur) is a transcriptional regulator that controls iron homeostasis in bacteria. Although the regulatory role of Fur in Escherichia coli is well characterized, most of the studies were conducted under routine culture conditions, i.e., in ambient oxygen concentration. To reveal potentially novel aspects of the Fur regulon in Salmonella enterica serovar Typhimurium under oxygen conditions similar to that encountered in the host, we compared the transcriptional profiles of the virulent wild-type strain (ATCC 14028s) and its isogenic Δfur strain under anaerobic conditions. Results Microarray analysis of anaerobically grown Δfur S. Typhimurium identified 298 differentially expressed genes. Expression of several genes controlled by Fnr and NsrR appeared to be also dependent on Fur. Furthermore, Fur was required for the activity of the cytoplasmic superoxide disumutases (MnSOD and FeSOD). The regulation of FeSOD gene, sodB, occurred via small RNAs (i.e., the ryhB homologs, rfrA and rfrB) with the aid of the RNA chaperone Hfq. The transcription of sodA was increased in Δfur; however, the enzyme was inactive due to the incorporation of iron instead of manganese in SodA. Additionally, in Δfur, the expression of the gene coding for the ferritin-like protein (ftnB) was down-regulated, while the transcription of the gene coding for the nitric oxide (NO·) detoxifying flavohemoglobin (hmpA) was up-regulated. The promoters of ftnB and hmpA do not contain recognized Fur binding motifs, which indicated their probable indirect regulation by Fur. However, Fur activation of ftnB was independent of Fnr. In addition, the expression of the gene coding for the histone-like protein, H-NS (hns) was increased in Δfur. This may explain the observed down-regulation of the tdc operon, responsible for the anaerobic degradation of threonine, and ftnB in Δfur. Conclusions This study determined that Fur is a positive factor in ftnB regulation, while serving to repress the expression of hmpA. Furthermore, Fur is required for the proper expression and activation of the antioxidant enzymes, FeSOD and MnSOD. Finally, this work identified twenty-six new targets of Fur regulation, and demonstrates that H-NS repressed genes are down-regulated in Δfur.
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Affiliation(s)
- Bryan Troxell
- Department of Microbiology, North Carolina State University, Raleigh, NC 27695-7615, USA
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23
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Economics of membrane occupancy and respiro-fermentation. Mol Syst Biol 2011; 7:500. [PMID: 21694717 PMCID: PMC3159977 DOI: 10.1038/msb.2011.34] [Citation(s) in RCA: 147] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Accepted: 04/27/2011] [Indexed: 02/04/2023] Open
Abstract
The authors propose that prokaryotic metabolism is fundamentally constrained by the cytoplasmic membrane surface area available for protein expression, and show that this constraint can explain previously puzzling physiological phenomena, including respiro-fermentation. We propose that prokaryotic cellular metabolism is fundamentally constrained by the finite cytoplasmic membrane surface area available for protein expression. A metabolic model of Escherichia coli updated to include a cytoplasmic membrane constraint is capable of predicting a variety of puzzling phenomena in this organism, including the respiro-fermentation phenomenon. Because the surface area to volume ratio is directly related to the morphology of the cell, this constraint provides a direct link between prokaryotic morphology and physiology. The potential relevance of this constraint to eukaryotes is discussed.
Many heterotrophs can produce ATP through both respiratory and fermentative pathways, allowing them to survive with or without oxygen. Since the molar ATP yield (molar ATP yield: mole of ATP produced/mole of substrate consumed) from respiration is about 15-fold higher than that from fermentation, ATP production via respiration is more efficient. Surprisingly, at high catabolic rate, many facultative aerobic organisms employ fermentative pathways simultaneously with respiration, even in the presence of abundant oxygen to produce ATP (Pfeiffer et al, 2001; Vemuri et al, 2006; Molenaar et al, 2009). This leads to an observable tradeoff between the ATP yield and the catabolic rate (Pfeiffer et al, 2001; Vemuri et al, 2006). This respiro-fermentation physiology is commonly observed in microorganisms, including Escherichia coli, Bacillus subtilis, Saccharomyces cerevisiae (Molenaar et al, 2009), as well as cancer cells (Vander Heiden et al, 2009). Despite extensive research, existing theories (Majewski and Domach, 1990; Varma and Palsson, 1994; Pfeiffer et al, 2001; Vazquez et al, 2008; Molenaar et al, 2009) cannot fully explain the respiro-fermentation phenomenon. The membrane economics theory We propose the hypothesis that the prokaryotic metabolism is fundamentally constrained by the finite cytoplasmic surface area available for protein expression—in order to maximize fitness, prokaryotic organisms such as E. coli must economically manage the expression of membrane proteins based on the membrane cost and the fitness benefit of the proteins. This hypothesis is proposed based on theoretical considerations (in this work), numerical analysis (Phillips and Milo, 2009), and experimental observation that the overexpression of non-respiratory membrane protein significantly reduces the oxygen consumption rate and induces aerobic fermentation (Wagner et al, 2007). Such a constraint on transmembrane protein expression may have significant physiological consequences in prokaryotes, such as E. coli, at higher catabolic rates. First, since both substrate transporters and respiratory enzymes are localized on the cytoplasmic membrane in prokaryotes, increased substrate uptake rates necessitates a decrease in the respiratory rate. This decrease in the respiratory rate, forces prokaryotes to process the additional substrate through the fermentative pathways, which are not catalyzed by transmembrane proteins, for continued ATP production. Furthermore, since the membrane requirement of an enzyme is inversely related to its turnover rate (see Materials and methods section in the manuscript), the faster and inefficient respiratory enzymes (such as Cyd-I and Cyd-II in E. coli) might be preferred over the slower and efficient enzymes (such as Cyo in E. coli), leading to an altered respiratory stoichiometry at higher catabolic rates. Finally, the absence of the respiratory enzymes under anaerobic conditions explains why the maximum glucose uptake rate (GUR) of E. coli is much higher. Applying membrane economics theory to E. coli To illustrate that the ‘membrane economics' theory could satisfactorily explain the physiological changes associated with the respiro-fermentation phenomenon in E. coli, we modified the genome-scale metabolic model of E. coli (Feist et al, 2007) to include a cytoplasmic membrane occupancy constraint. Using ‘relative membrane costs' calculated from experimental data, the new modeling framework—FBA with membrane economics (FBAME)—predicted that wild-type E. coli has a GUR of 10.7 mmol/gdw/h, an oxygen uptake rate (OUR) of 15.8 mmol/gdw/h, and a specific growth rate of 0.69 per hour during aerobic growth with excess glucose. FBAME also predicted that under the same growth condition, an E. coli knockout strain with no cytochromes has a GUR of 18 mmol/gdw/h and growth rate of 0.42. These values agree very well with the reported experimental values for E. coli grown in batch cultures (Vemuri et al, 2006; Portnoy et al, 2008), which supports our hypothesis that the higher GUR of E. coli during glucose-excess anaerobiosis than under aerobic conditions is due to the absence of the respiratory enzymes. We also simulated the aerobic growth of E. coli in glucose-limited chemostat using both conventional FBA and FBAME. FBAME successfully predicted the growth rate and yield changes with respect to increasing GUR (Figure 2A and B), as well as the aerobic production of acetate (Figure 2C) and concomitant repression of oxygen uptake (Figure 2D). On the other hand, traditional FBA significantly overestimated the growth rate and yield at higher GURs (this overestimation cannot be explained by varying the growth-associated maintenance (GAM) energy parameter; Figure 2A), and failed to predict the decrease in yield independent of acetate overflow and reduction in oxygen uptake at higher GURs (Figure 2). In addition, FBAME was able to predict the reduction of the TCA cycle activities at higher uptake rates (Figure 3C and D) as well as the selective expression of Cyo and Cyd-II at lower uptake rates (Figure 3A and B), whereas conventional FBA cannot predict the expression of inefficient Cyd-II. These predictions agree with the gene expression data from glucose-limited chemostat (Figure 3). Given the simplicity of the constraint we imposed, our model predictions agree surprisingly well with experimental observations, lending strong credibility to the membrane economics hypothesis. Concluding remarks Although it has been long suggested that cellular evolution are governed by non-adjustable mechanistic constraints (Palsson, 2000; Papin et al, 2005; Novak et al, 2006), to date, most metabolic models rely on empirically derived parameters such as glucose and OUR. In this article, we showed that complex phenomena, such as the respiro-fermentation in E. coli, could be satisfactorily explained and accurately predicted by using constraint-based optimization by introducing a simple mechanistic constraint on membrane enzyme occupancy. Given that the cytoplasmic membrane occupancy constraint is directly related to the surface area to volume (S/V) ratio of the cell, it is possible that this constraint resulted in the evolution of mitochondria in eukaryotes as mitochondria allows for a significantly increased S/V ratio. Further efforts to elucidate such fundamental cellular constraints as well as the underlying design principles could significantly improve our understanding of the regulation and evolution of metabolism. The simultaneous utilization of efficient respiration and inefficient fermentation even in the presence of abundant oxygen is a puzzling phenomenon commonly observed in bacteria, yeasts, and cancer cells. Despite extensive research, the biochemical basis for this phenomenon remains obscure. We hypothesize that the outcome of a competition for membrane space between glucose transporters and respiratory chain (which we refer to as economics of membrane occupancy) proteins influences respiration and fermentation. By incorporating a sole constraint based on this concept in the genome-scale metabolic model of Escherichia coli, we were able to simulate respiro-fermentation. Further analysis of the impact of this constraint revealed differential utilization of the cytochromes and faster glucose uptake under anaerobic conditions than under aerobic conditions. Based on these simulations, we propose that bacterial cells manage the composition of their cytoplasmic membrane to maintain optimal ATP production by switching between oxidative and substrate-level phosphorylation. These results suggest that the membrane occupancy constraint may be a fundamental governing constraint of cellular metabolism and physiology, and establishes a direct link between cell morphology and physiology.
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Kumar R, Shimizu K. Transcriptional regulation of main metabolic pathways of cyoA, cydB, fnr, and fur gene knockout Escherichia coli in C-limited and N-limited aerobic continuous cultures. Microb Cell Fact 2011; 10:3. [PMID: 21272324 PMCID: PMC3037301 DOI: 10.1186/1475-2859-10-3] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2010] [Accepted: 01/27/2011] [Indexed: 01/09/2023] Open
Abstract
Background It is important to understand the cellular responses emanating from environmental perturbations to redesign the networks for practical applications. In particular, the carbon (C) metabolism, nitrogen (N) assimilation, and energy generation are by far important, where those are interconnected and integrated to maintain cellular integrity. In our previous study, we investigated the effect of C/N ratio on the metabolic regulation of gdhA, glnL, glt B,D mutants as well as wild type Escherichia coli (Kumar and Shimizu, MCF, 1-17, 9:8,2010), where it was shown that the transcript levels of cyoA and cydB which encode the terminal oxidases, fnr and fur which encode global regulators were significantly up-regulated under N-limited condition as compared to C-limited condition. In the present study, therefore, the effects of such single-gene knockout on the metabolic regulation were investigated to clarify the roles of those genes in the aerobic continuous culture at the dilution rate of 0.2 h-1. Results The specific glucose consumption rates and the specific CO2 production rates of cyoA, cydB, fnr, and fur mutants were all increased as compared to the wild type under both C-limited and N-limited conditions. The former phenomenon was consistent with the up-regulations of the transcript levels of ptsG and ptsH, which are consistent with down-regulations of crp and mlc genes. Moreover, the increase in the specific glucose consumption rate was also caused by up-regulations of the transcript levels of pfkA, pykF and possibly zwf, where those are consistent with the down regulations of cra, crp and mlc genes. Moreover, the transcript levels of rpoN together with glnK, glnB, glnE were up-regulated, and thus the transcript levels of glnA,L,G, and gltB,D as well as nac were up-regulated, while gdhA was down-regulated. This implies the interconnection between cAMP-Crp and PII-Ntr systems. Moreover, cyoA, cydB, fnr and fur gene deletions up-regulated the transcript levels of respiration (nuoA, ndh, cyoA, cydB, and atpA) and the oxidative stress related genes such as soxR, S and sodA, where this was further enhanced under N-limitation. In the cases of cyoA and cydB mutants, arcA, fnr, fur, cydB (for cyoA mutant), and cyoA (for cydB mutant) genes were up-regulated, which may be due to incomplete oxidation of quinol. It was also shown that fur gene transcript level was up-regulated in accordance with the activation of respiratory chain genes. It was shown that the deletion of fur gene activated the enterobactin pathway. Conclusion The present result demonstrated how the fermentation characteristics could be explained by the transcript levels of metabolic pathway genes as well as global regulators in relation to the knockout of such single genes as cyoA, cydB, fnr, and fur, and clarified the complex gene network regulation in relation to glycolysis, TCA cycle, respiration, and N-regulated pathways. The present result is quite important in understanding the metabolic regulation for metabolic engineering. Moreover, the present result may be useful in improving the specific glucose consumption rate and activation of the TCA cycle by modulating the respiratory chain genes and the related global regulators. The result obtained under N-limited condition may be useful for the heterologous protein production under N-limitation.
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Affiliation(s)
- Rahul Kumar
- Department of Bioscience and Bioinformatics, Kyushu Institute of Technology, Iizuka, Fukuoka, Japan
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Pin C, Rolfe MD, Muñoz-Cuevas M, Hinton JCD, Peck MW, Walton NJ, Baranyi J. Network analysis of the transcriptional pattern of young and old cells of Escherichia coli during lag phase. BMC SYSTEMS BIOLOGY 2009; 3:108. [PMID: 19917103 PMCID: PMC2780417 DOI: 10.1186/1752-0509-3-108] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2009] [Accepted: 11/16/2009] [Indexed: 11/18/2022]
Abstract
Background The aging process of bacteria in stationary phase is halted if cells are subcultured and enter lag phase and it is then followed by cellular division. Network science has been applied to analyse the transcriptional response, during lag phase, of bacterial cells starved previously in stationary phase for 1 day (young cells) and 16 days (old cells). Results A genome scale network was constructed for E. coli K-12 by connecting genes with operons, transcription and sigma factors, metabolic pathways and cell functional categories. Most of the transcriptional changes were detected immediately upon entering lag phase and were maintained throughout this period. The lag period was longer for older cells and the analysis of the transcriptome revealed different intracellular activity in young and old cells. The number of genes differentially expressed was smaller in old cells (186) than in young cells (467). Relatively, few genes (62) were up- or down-regulated in both cultures. Transcription of genes related to osmotolerance, acid resistance, oxidative stress and adaptation to other stresses was down-regulated in both young and old cells. Regarding carbohydrate metabolism, genes related to the citrate cycle were up-regulated in young cells while old cells up-regulated the Entner Doudoroff and gluconate pathways and down-regulated the pentose phosphate pathway. In both old and young cells, anaerobic respiration and fermentation pathways were down-regulated, but only young cells up-regulated aerobic respiration while there was no evidence of aerobic respiration in old cells. Numerous genes related to DNA maintenance and replication, translation, ribosomal biosynthesis and RNA processing as well as biosynthesis of the cell envelope and flagellum and several components of the chemotaxis signal transduction complex were up-regulated only in young cells. The genes for several transport proteins for iron compounds were up-regulated in both young and old cells. Numerous genes encoding transporters for carbohydrates and organic alcohols and acids were down-regulated in old cells only. Conclusion Network analysis revealed very different transcriptional activities during the lag period in old and young cells. Rejuvenation seems to take place during exponential growth by replicative dilution of old cellular components.
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Affiliation(s)
- Carmen Pin
- Institute of Food Research, Norwich NR4 7UA, UK.
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Cytochrome d but not cytochrome o rescues the toluidine blue growth sensitivity of arc mutants of Escherichia coli. J Bacteriol 2009; 192:391-9. [PMID: 19897650 DOI: 10.1128/jb.00881-09] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The Arc (anoxic redox control) two-component signal transduction system, consisting of the ArcB sensor kinase and the ArcA response regulator, allows adaptive responses of Escherichia coli to changes of O(2) availability. The arcA gene was previously known as the dye gene because null mutants were growth sensitive to the photosensitizer redox dyes toluidine blue and methylene blue, a phenotype whose molecular basis still remains elusive. In this study we report that the toluidine blue O (TBO) effect on the arc mutants is light independent and observed only during aerobic growth conditions. Moreover, 16 suppressor mutants with restored growth were generated and analyzed. Thirteen of those possessed insertion elements upstream of the cydAB operon, rendering its expression ArcA independent. Also, it was found that, in contrast to cythocrome d, cythocrome o was not able to confer toluidine blue resistance to arc mutants, thereby representing an intriguing difference between the two terminal oxidases. Finally, a mechanism for TBO sensitivity and resistance is discussed.
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Lewis JP, Iyer D, Anaya-Bergman C. Adaptation of Porphyromonas gingivalis to microaerophilic conditions involves increased consumption of formate and reduced utilization of lactate. MICROBIOLOGY-SGM 2009; 155:3758-3774. [PMID: 19684063 DOI: 10.1099/mic.0.027953-0] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Porphyromonas gingivalis, previously classified as a strict anaerobe, can grow in the presence of low concentrations of oxygen. Microarray analysis revealed alteration in gene expression in the presence of 6 % oxygen. During the exponential growth phase, 96 genes were upregulated and 79 genes were downregulated 1.4-fold. Genes encoding proteins that play a role in oxidative stress protection were upregulated, including alkyl hydroperoxide reductase (ahpCF), superoxide dismutase (sod) and thiol peroxidase (tpx). Significant changes in gene expression of proteins that mediate oxidative metabolism, such as cytochrome d ubiquinol oxidase-encoding genes, cydA and cydB, were detected. The expression of genes encoding formate uptake transporter (PG0209) and formate tetrahydrofolate ligase (fhs) was drastically elevated, which indicates that formate metabolism plays a major role under aerobic conditions. The concomitant reduction of expression of a gene encoding the lactate transporter PG1340 suggests decreased utilization of this nutrient. The concentrations of both formate and lactate were assessed in culture supernatants and cells, and they were in agreement with the results obtained at the transcriptional level. Also, genes encoding gingipain protease secretion/maturation regulator (porR) and protease transporter (porT) had reduced expression in the presence of oxygen, which also correlated with reduced protease activities under aerobic conditions. In addition, metal transport was affected, and while iron-uptake genes such as the genes encoding the haemin uptake locus (hmu) were downregulated, expression of manganese transporter genes, such as feoB2, was elevated in the presence of oxygen. Finally, genes encoding putative regulatory proteins such as extracellular function (ECF) sigma factors as well as small proteins had elevated expression levels in the presence of oxygen. As P. gingivalis is distantly related to the well-studied model organism Escherichia coli, results from our work may provide further understanding of oxygen metabolism and protection in other related bacteria belonging to the phylum Bacteroidetes.
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Affiliation(s)
- Janina P Lewis
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA, USA.,Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, VA, USA.,The Philips Institute of Oral and Craniofacial Molecular Biology, Virginia Commonwealth University, Richmond, VA, USA
| | - Divya Iyer
- The Philips Institute of Oral and Craniofacial Molecular Biology, Virginia Commonwealth University, Richmond, VA, USA
| | - Cecilia Anaya-Bergman
- University of San Luis, San Luis, Argentina.,The Philips Institute of Oral and Craniofacial Molecular Biology, Virginia Commonwealth University, Richmond, VA, USA
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Qiao Y, Li CM, Lu Z, Ling H, Kang A, Chang MW. A time-course transcriptome analysis of Escherichia coli with direct electrochemistry behavior in microbial fuel cells. Chem Commun (Camb) 2009:6183-5. [DOI: 10.1039/b912003c] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Yang K, Borisov VB, Konstantinov AA, Gennis RB. The fully oxidized form of the cytochrome bd quinol oxidase from E. coli does not participate in the catalytic cycle: direct evidence from rapid kinetics studies. FEBS Lett 2008; 582:3705-9. [PMID: 18823983 DOI: 10.1016/j.febslet.2008.09.038] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2008] [Revised: 09/13/2008] [Accepted: 09/16/2008] [Indexed: 11/25/2022]
Abstract
Cytochrome bd catalyzes the two-electron oxidation of either ubiquinol or menaquinol and the four-electron reduction of O(2) to H(2)O. In the current work, the rates of reduction of the fully oxidized and oxoferryl forms of the enzyme by the 2-electron donor ubiquinol-1 and single electron donor N,N,N',N'-tetramethyl-p-phenylendiamine (TMPD) have been examined by stopped-flow techniques. Reduction of the all-ferric form of the enzyme is 1000-fold slower than required for a step in the catalytic cycle, whereas the observed rates of reduction of the oxoferryl and singly-reduced forms of the cytochrome are consistent with the catalytic turnover. The data support models of the catalytic cycle which do not include the fully oxidized form of the enzyme as an intermediate.
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Affiliation(s)
- Ke Yang
- Department of Biochemistry, University of Illinois, Urbana, IL 61801, USA
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Jang HJ, Nde C, Toghrol F, Bentley WE. Microarray analysis of toxicogenomic effects of ortho-phenylphenol in Staphylococcus aureus. BMC Genomics 2008; 9:411. [PMID: 18793396 PMCID: PMC2562396 DOI: 10.1186/1471-2164-9-411] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2008] [Accepted: 09/15/2008] [Indexed: 12/02/2022] Open
Abstract
Background Staphylococcus aureus (S. aureus), is responsible for many infectious diseases, ranging from benign skin infections to life-threatening endocarditis and toxic shock syndrome. Ortho-phenylphenol (OPP) is an antimicrobial agent and an active ingredient of EPA-registered disinfectants with wide human exposure in various agricultural, hospital and veterinary disinfectant products. Despite many uses, an understanding of a cellular response to OPP and it's mechanism of action, targeted genes, and the connectivity between targeted genes and the rest of cell metabolism remains obscure. Results Herein, we performed a genome-wide transcriptome analysis of the cellular responses of S. aureus when exposed to 0.82 mM of OPP for 20 and 60 min. Our data indicated that OPP downregulated the biosynthesis of many amino acids, which are required for protein synthesis. In particular, the genes encoding the enzymes of the diaminopimelate (DAP) pathway which results in lysine biosynthesis were significantly downregualted. Intriguingly, we revealed that the transcription of genes encoding ribosomal proteins was upregulated by OPP and at the same time, the genes encoding iron acquisition and transport were downregulated. The genes encoding virulence factors were upregulated and genes encoding phospholipids were downregulated upon 20 min exposure to OPP. Conclusion By using microarray analysis that enables us to simultaneously and globally examine the complete transcriptome during cellular responses, we have revealed novel information regarding the mode of action of OPP on Staphylococcus: OPP inhibits anabolism of many amino acids and highly downregulates the genes that encode the enzymes involved in the DAP pathway. Lysine and DAP are essential for building up the peptidoglycan cell wall. It was concluded that the mode of action of OPP is similar to the mechanism of action of some antibiotics. The discovery of this phenomenon provides useful information that will benefit further antimicrobial research on S. aureus.
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Affiliation(s)
- Hyeung-Jin Jang
- Center for Biosystems Research, University of Maryland Biotechnology Institute, College Park, Maryland 20742, USA.
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31
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Partridge JD, Sanguinetti G, Dibden DP, Roberts RE, Poole RK, Green J. Transition of Escherichia coli from Aerobic to Micro-aerobic Conditions Involves Fast and Slow Reacting Regulatory Components. J Biol Chem 2007; 282:11230-7. [PMID: 17307737 DOI: 10.1074/jbc.m700728200] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Understanding life at a systems level is a major aim of biology. The bacterium Escherichia coli offers one of the best opportunities to achieve this goal. It is a metabolically versatile bacterium able to respond to changes in oxygen availability. This ability is a crucial component of its lifestyle, allowing it to thrive in aerobic external environments and under the oxygen-starved conditions of a host gut. The controlled growth conditions of chemostat culture were combined with transcript profiling to investigate transcriptome dynamics during the transition from aerobic to micro-aerobic conditions. In addition to predictable changes in transcripts encoding proteins of central metabolism, the abundances of transcripts involved in homeostasis of redox-reactive metals (Cu and Fe), and cell envelope stress were significantly altered. To gain further insight into the responses of the regulatory networks, the activities of key transcription factors during the transition to micro-aerobic conditions were inferred using a probabilistic modeling approach, which revealed that the response of the direct oxygen sensor FNR was rapid and overshot, whereas the indirect oxygen sensor ArcA reacted more slowly. Similarly, the cell envelope stress sensors RpoE and CpxR reacted rapidly and more slowly, respectively. Thus, it is suggested that combining rapid and slow reacting components in regulatory networks might be a feature of systems in which a signal is perceived by two or more functionally related transcription factors controlling overlapping regulons.
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Affiliation(s)
- Jonathan D Partridge
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield S10 2TN, United Kingdom
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Noda S, Takezawa Y, Mizutani T, Asakura T, Nishiumi E, Onoe K, Wada M, Tomita F, Matsushita K, Yokota A. Alterations of cellular physiology in Escherichia coli in response to oxidative phosphorylation impaired by defective F1-ATPase. J Bacteriol 2006; 188:6869-76. [PMID: 16980490 PMCID: PMC1595526 DOI: 10.1128/jb.00452-06] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2006] [Accepted: 07/23/2006] [Indexed: 12/13/2022] Open
Abstract
The physiological changes in an F1-ATPase-defective mutant of Escherichia coli W1485 growing in a glucose-limited chemostat included a decreased growth yield (60%) and increased specific rates of both glucose consumption (168%) and respiration (171%). Flux analysis revealed that the mutant showed approximately twice as much flow in glycolysis but only an 18% increase in the tricarboxylic acid (TCA) cycle, owing to the excretion of acetate, where most of the increased glycolytic flux was directed. Genetic and biochemical analyses of the mutant revealed the downregulation of many TCA cycle enzymes, including citrate synthase, and the upregulation of the pyruvate dehydrogenase complex in both transcription and enzyme activities. These changes seemed to contribute to acetate excretion in the mutant. No transcriptional changes were observed in the glycolytic enzymes, despite the enhanced glycolysis. The most significant alterations were found in the respiratory-chain components. The total activity of NADH dehydrogenases (NDHs) and terminal oxidases increased about twofold in the mutant, which accounted for its higher respiration rate. These changes arose primarily from the increased (3.7-fold) enzyme activity of NDH-2 and an increased amount of cytochrome bd in the mutant. Transcriptional upregulation appeared to be involved in these phenomena. As NDH-2 cannot generate an electrochemical gradient of protons and as cytochrome bd is inferior to cytochrome bo3 in this ability, the mutant was able to recycle NADH at a higher rate than the parent and avoid generating an excess proton-motive force. We discuss the physiological benefits of the alterations in the mutant.
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Affiliation(s)
- Sakiko Noda
- Laboratory of Microbial Physiology, Hokkaido University, Sapporo, Hokkaido 060-8589, Japan
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Morales G, Ugidos A, Rojo F. Inactivation of the Pseudomonas putida cytochrome o ubiquinol oxidase leads to a significant change in the transcriptome and to increased expression of the CIO and cbb3-1 terminal oxidases. Environ Microbiol 2006; 8:1764-74. [PMID: 16958757 DOI: 10.1111/j.1462-2920.2006.01061.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Pseudomonas putida KT2440 contains a branched aerobic respiratory chain with several terminal oxidases. Inactivation of the cyo terminal ubiquinol oxidase has little effect on growth rate but is known to relieve the inhibition by global control that modulates induction of genes required to assimilate alkanes in cells growing in the presence of preferred carbon sources. We show that inactivation of other terminal oxidases has no effect on regulation of the alkane degradation pathway, which points to cyo as the oxidase that transmits a regulatory signal related to the activity of the electron transport chain. Using a genome-wide DNA microarray we found that inactivation of cyo has a significant effect on the transcriptome, supporting that it participates in global regulation of gene expression. Among the genes affected stand out those coding for transporters of organic acids, porins, transcriptional regulators and terminal oxidases. Real-time reverse transcription polymerase chain reaction (RT-PCR) showed that, in cells growing exponentially in a complete medium, the absence of cyo was compensated by increased expression of the cyanide-insensitive and cbb3-1 terminal oxidases, while cbb3-2 and aa3 oxidases remained unaffected. When cells enter into stationary phase cyo levels decrease and inhibition of the alkane degradation genes ceases. This was paralleled by upregulation of the cyanide-insensitive, cbb3-1, cbb3-2 and aa3 terminal oxidases. The results suggest that P. putida adapts the composition of the electron transport chain not only to optimize energy generation, but also to influence the transcriptome profile of the cell through global control of gene expression.
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Affiliation(s)
- Gracia Morales
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Campus de la Universidad Autónoma de Madrid, Cantoblanco, 28049-Madrid, Spain
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Cho BK, Knight EM, Palsson BØ. Transcriptional regulation of the fad regulon genes of Escherichia coli by ArcA. MICROBIOLOGY-SGM 2006; 152:2207-2219. [PMID: 16849788 DOI: 10.1099/mic.0.28912-0] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
ArcA is a global transcription factor required for optimal growth of Escherichia coli during anaerobic growth. In this study, the role of ArcA on the transcriptional regulatory subnetwork of the fad regulon was investigated. Gene expression profiles of deletion mutants (Delta arcA, Delta fadR and Delta arcA/Delta fadR) indicated that (i) ArcA is a major transcription factor for the transcriptional regulation of fatty acid metabolism in the absence of oxygen, and (ii) ArcA and FadR cooperatively regulate the fad regulon under anaerobic conditions. To determine the direct interaction between ArcA and the promoters of the fad regulon genes, chromatin immunoprecipitation (ChIP) analysis was performed. ChIP analysis suggested that ArcA directly binds to the promoter regions of the fad regulon genes in vivo. An ArcA-binding motif was identified from known binding sequences and predicted putative binding sites in the promoter regions of the fad regulon genes. These results indicate that ArcA directly represses the expression of fad regulon genes during anaerobic growth.
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Affiliation(s)
- Byung-Kwan Cho
- Department of Bioengineering, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0412, USA
| | - Eric M Knight
- Department of Bioengineering, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0412, USA
| | - Bernhard Ø Palsson
- Department of Bioengineering, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0412, USA
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Partridge JD, Scott C, Tang Y, Poole RK, Green J. Escherichia coli Transcriptome Dynamics during the Transition from Anaerobic to Aerobic Conditions. J Biol Chem 2006; 281:27806-15. [PMID: 16857675 DOI: 10.1074/jbc.m603450200] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Escherichia coli is a metabolically versatile bacterium that is able to grow in the presence and absence of oxygen. Several previous transcript-profiling experiments have compared separate anaerobic and aerobic cultures. Here the process of adaptation was investigated by determining changes in transcript profiles when anaerobic steady-state cultures were perturbed by the introduction of air. Within 5 min of culture aeration the abundances of transcripts associated with anaerobic metabolism were decreased, whereas transcripts associated with aerobic metabolism were increased. In addition to the rapid switch to aerobic central metabolism, transcript profiling, supported by experiments with relevant mutants, revealed transient changes suggesting that the peroxide stress response, methionine biosynthesis, and degradation of putrescine play important roles during the adaptation to aerobic conditions.
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Affiliation(s)
- Jonathan D Partridge
- Department of Molecular Biology and Biotechnology, the University of Sheffield, Sheffield S10 2TN, United Kingdom
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Chang W, Small DA, Toghrol F, Bentley WE. Global transcriptome analysis of Staphylococcus aureus response to hydrogen peroxide. J Bacteriol 2006; 188:1648-59. [PMID: 16452450 PMCID: PMC1367260 DOI: 10.1128/jb.188.4.1648-1659.2006] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Staphylococcus aureus responds with protective strategies against phagocyte-derived reactive oxidants to infect humans. Herein, we report the transcriptome analysis of the cellular response of S. aureus to hydrogen peroxide-induced oxidative stress. The data indicate that the oxidative response includes the induction of genes involved in virulence, DNA repair, and notably, anaerobic metabolism.
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Affiliation(s)
- Wook Chang
- Center for Biosystems Research, University of Maryland Biotechnology Institute, College Park 20742, USA
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Machado P, Félix R, Rodrigues R, Oliveira S, Rodrigues-Pousada C. Characterization and expression analysis of the cytochrome bd oxidase operon from Desulfovibrio gigas. Curr Microbiol 2006; 52:274-81. [PMID: 16550467 DOI: 10.1007/s00284-005-0165-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2005] [Accepted: 11/14/2005] [Indexed: 11/27/2022]
Abstract
Although classified as anaerobic, Desulfovibrio gigas contains a functional canonical membrane respiratory chain, including a cytochrome bd quinol oxidase as its terminal element. In the present study, we report the identification of the operon cydAB encoding the two subunits of cytochrome bd from this bacterium. Two hypothetical promoter regions and sequences resembling transcriptional regulators-binding sites have been identified. Amino acid sequence analysis revealed a high similarity to cytochrome bd from other organisms, presenting the conserved residues typical from these proteins. Reverse transcription polymerase chain reaction (RT-PCR) and Northern blot analysis confirmed the operon transcription. Gene expression was assessed by real-time RT-PCR in cells grown in different media and under exposure to oxygen and nitric oxide. mRNA levels were slightly enhanced in the presence of 150 microM: NO. However, in the presence of 10 microM: NO, a decrease was observed of the steady-state population of cydAB mRNA. No considerable effect was observed in the presence of fumarate/sulfate medium, 60 microM: O2 or 10 microM: NO.
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Affiliation(s)
- Patrícia Machado
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Apartado 127, 2780-901, Oeiras, Portugal
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38
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Jones AM, Boucher PE, Williams CL, Stibitz S, Cotter PA. Role of BvgA phosphorylation and DNA binding affinity in control of Bvg-mediated phenotypic phase transition in Bordetella pertussis. Mol Microbiol 2006; 58:700-13. [PMID: 16238621 DOI: 10.1111/j.1365-2958.2005.04875.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
To investigate the mechanism by which the Bordetella BvgAS phosphorelay controls expression of at least three distinct phenotypic phases, we isolated and characterized two B. pertussis mutants that were able to express Bvg- and Bvg(i) phase phenotypes but not Bvg+ phase phenotypes. In both cases, the mutant phenotype was due to a single nucleotide change in bvgA resulting in a single amino acid substitution in BvgA. In vitro phosphorylation assays showed that BvgA containing the T194M substitution was significantly impaired in its ability to use either BvgS or acetyl phosphate as a substrate for phosphorylation. Binding studies indicated that this mutant protein was able to bind an oligonucleotide containing a high-affinity BvgA binding site in a manner similar to wild-type BvgA, but was defective for binding the fhaB promoter in the absence of RNA polymerase (RNAP). By contrast, BvgA containing the R152H substitution had wild-type phosphorylation properties but was severely defective in its ability to bind either the high-affinity BvgA binding site-containing oligonucleotide or the fhaB promoter by itself. Both mutant BvgA proteins were able to bind the fhaB promoter in the presence of RNAP however, demonstrating the profound effect that RNAP has on stabilizing the ternary complexes between promoter DNA, BvgA and RNAP. Our results are consistent with the hypothesis that BvgAS controls expression of multiple phenotypic phases by adjusting the intracellular concentration of BvgA-P and they demonstrate the additive nature of BvgA binding site affinity and protein-protein interactions at different Bvg-regulated promoters.
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Affiliation(s)
- Allison M Jones
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA 93109-9610, USA
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39
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Constantinidou C, Hobman JL, Griffiths L, Patel MD, Penn CW, Cole JA, Overton TW. A reassessment of the FNR regulon and transcriptomic analysis of the effects of nitrate, nitrite, NarXL, and NarQP as Escherichia coli K12 adapts from aerobic to anaerobic growth. J Biol Chem 2005; 281:4802-15. [PMID: 16377617 DOI: 10.1074/jbc.m512312200] [Citation(s) in RCA: 207] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The transcription factor FNR, the regulator of fumarate and nitrate reduction, regulates major changes as Escherichia coli adapts from aerobic to anaerobic growth. In an anaerobic glycerol/trimethylamine N-oxide/fumarate medium, the fnr mutant grew as well as the parental strain, E. coli K12 MG1655, enabling us to reveal the response to oxygen, nitrate, and nitrite in the absence of glucose repression or artifacts because of variations in growth rate. Hence, many of the discrepancies between previous microarray studies of the E. coli FNR regulon were resolved. The current microarray data confirmed 31 of the previously characterized FNR-regulated operons. Forty four operons not previously known to be included in the FNR regulon were activated by FNR, and a further 28 operons appeared to be repressed. For each of these operons, a match to the consensus FNR-binding site sequence was identified. The FNR regulon therefore minimally includes at least 103, and possibly as many as 115, operons. Comparison of transcripts in the parental strain and a narXL deletion mutant revealed that transcription of 51 operons is activated, directly or indirectly, by NarL, and a further 41 operons are repressed. The narP gene was also deleted from the narXL mutant to reveal the extent of regulation by phosphorylated NarP. Fourteen promoters were more active in the narP+ strain than in the mutant, and a further 37 were strongly repressed. This is the first report that NarP might function as a global repressor as well as a transcription activator. The data also revealed possible new defense mechanisms against reactive nitrogen species.
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Ogasawara H, Teramoto J, Yamamoto S, Hirao K, Yamamoto K, Ishihama A, Utsumi R. Negative regulation of DNA repair gene (uvrA) expression by ArcA/ArcB two-component system inEscherichia coli. FEMS Microbiol Lett 2005; 251:243-9. [PMID: 16140472 DOI: 10.1016/j.femsle.2005.08.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2005] [Revised: 07/25/2005] [Accepted: 08/05/2005] [Indexed: 11/18/2022] Open
Abstract
The ArcA/ArcB two-component signal transduction system of Escherichia coli regulates gene expression in response to the redox conditions of growth. In this study, uvrA gene expression was repressed when ArcA was induced in E. coli. Transcription of uvrA increased in DeltaarcA and DeltaarcB strains more than in the wild-type strain, whose trend was remarkable under the anaerobic condition. In the wild-type strain grown in the presence of DTT (10 mM), the uvrA gene expression was also repressed. Furthermore, the results of in vitro transcription and DNase I footprinting experiments indicated that ArcA specifically bound to the ArcA box [(A/T)GTTAATTA(A/T)] in the uvrA promoter and represses its transcription. These results suggest that the ArcA/ArcB two-component system works to negatively regulate uvrA gene expression.
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Affiliation(s)
- Hiroshi Ogasawara
- Department of Bioscience and Biotechnology, Graduate School of Agriculture, Kinki University, 3327-204 Nakamachi, Nara 631-8505, Japan
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41
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Rychlik I, Barrow PA. Salmonella stress management and its relevance to behaviour during intestinal colonisation and infection. FEMS Microbiol Rev 2005; 29:1021-40. [PMID: 16023758 DOI: 10.1016/j.femsre.2005.03.005] [Citation(s) in RCA: 145] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2004] [Revised: 03/04/2005] [Accepted: 03/30/2005] [Indexed: 01/13/2023] Open
Abstract
The enteric pathogen Salmonella enterica is exposed to a number of stressful environments during its life cycle within and outside its various hosts. During intestinal colonisation Salmonella is successively exposed to acid pH in the stomach, to the detergent-like activity of bile, to decreasing oxygen supply, to the presence of multiple metabolites produced by the normal gut microflora and finally it is exposed to cationic antimicrobial peptides present on the surface of epithelial cells. There are four major regulators controlling relevant stress responses in Salmonella, namely RpoS, PhoPQ, Fur and OmpR/EnvZ. Except for Fur, inactivation of genes encoding the other stress regulators results in attenuated virulence and such mutants can therefore be considered as vaccine candidates. In contrast, a decrease in oxygen supply monitored by Fnr and ArcAB, or oxidative stress controlled by OxyR and SoxRS is not regarded as a stress associated with host colonisation since inactivation of either of these systems does not result in reductions in colonisation. The role of quorum-sensing through luxS and sdiA is also considered as a regulator of virulence and colonisation.
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Affiliation(s)
- Ivan Rychlik
- Veterinary Research Institute, Hudcova 70, 621 32 Brno, Czech Republic.
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42
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Jubelin G, Vianney A, Beloin C, Ghigo JM, Lazzaroni JC, Lejeune P, Dorel C. CpxR/OmpR interplay regulates curli gene expression in response to osmolarity in Escherichia coli. J Bacteriol 2005; 187:2038-49. [PMID: 15743952 PMCID: PMC1064031 DOI: 10.1128/jb.187.6.2038-2049.2005] [Citation(s) in RCA: 215] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2004] [Accepted: 12/06/2004] [Indexed: 11/20/2022] Open
Abstract
Curli fibers could be described as a virulence factor able to confer adherence properties to both abiotic and eukaryotic surfaces. The ability to adapt rapidly to changing environmental conditions through signal transduction pathways is crucial for the growth and pathogenicity of bacteria. OmpR was shown to activate csgD expression, resulting in curli production. The CpxR regulator was shown to negatively affect curli gene expression when binding to its recognition site that overlaps the csgD OmpR-binding site. This study was undertaken to clarify how the interplay between the two regulatory proteins, OmpR and CpxR, can affect the transcription of the curli gene in response to variation of the medium osmolarity. Band-shift assays with purified CpxR proteins indicate that CpxR binds to the csgD promoter region at multiple sites that are ideally positioned to explain the csg repression activity of CpxR. To understand the physiological meaning of this in vitro molecular phenomenon, we analyzed the effects of an osmolarity shift on the two-component pathway CpxA/CpxR. We establish here that the Cpx pathway is activated at both transcriptional and posttranscriptional levels in response to a high osmolarity medium and that CpxR represses csgD expression in high-salt-content medium, resulting in low curli production. However, csgD repression in response to high sucrose content is not mediated by CpxR but by the global regulatory protein H-NS. Therefore, multiple systems (EnvZ/OmpR, Cpx, Rcs, and H-NS) appear to be involved in sensing environmental osmolarity, leading to sophisticated regulation of the curli genes.
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Affiliation(s)
- Gregory Jubelin
- Unité de Microbiologie et Génétique Composante INSA, Villeurbanne, France
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Salmon KA, Hung SP, Steffen NR, Krupp R, Baldi P, Hatfield GW, Gunsalus RP. Global gene expression profiling in Escherichia coli K12: effects of oxygen availability and ArcA. J Biol Chem 2005; 280:15084-96. [PMID: 15699038 DOI: 10.1074/jbc.m414030200] [Citation(s) in RCA: 158] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The ArcAB two-component system of Escherichia coli regulates the aerobic/anaerobic expression of genes that encode respiratory proteins whose synthesis is coordinated during aerobic/anaerobic cell growth. A genomic study of E. coli was undertaken to identify other potential targets of oxygen and ArcA regulation. A group of 175 genes generated from this study and our previous study on oxygen regulation (Salmon, K., Hung, S. P., Mekjian, K., Baldi, P., Hatfield, G. W., and Gunsalus, R. P. (2003) J. Biol. Chem. 278, 29837-29855), called our gold standard gene set, have p values <0.00013 and a posterior probability of differential expression value of 0.99. These 175 genes clustered into eight expression patterns and represent genes involved in a large number of cell processes, including small molecule biosynthesis, macromolecular synthesis, and aerobic/anaerobic respiration and fermentation. In addition, 119 of these 175 genes were also identified in our previous study of the fnr allele. A MEME/weight matrix method was used to identify a new putative ArcA-binding site for all genes of the E. coli genome. 16 new sites were identified upstream of genes in our gold standard set. The strict statistical analyses that we have performed on our data allow us to predict that 1139 genes in the E. coli genome are regulated either directly or indirectly by the ArcA protein with a 99% confidence level.
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Affiliation(s)
- Kirsty A Salmon
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, California 90095-1489, USA
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García-González V, Govantes F, Porrúa O, Santero E. Regulation of the Pseudomonas sp. strain ADP cyanuric acid degradation operon. J Bacteriol 2005; 187:155-67. [PMID: 15601699 PMCID: PMC538813 DOI: 10.1128/jb.187.1.155-167.2005] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas sp. strain ADP is the model strain for studying bacterial degradation of the s-triazine herbicide atrazine. In this work, we focused on the expression of the atzDEF operon, involved in mineralization of the central intermediate of the pathway, cyanuric acid. Expression analysis of atzD-lacZ fusions in Pseudomonas sp. strain ADP and Pseudomonas putida showed that atzDEF is subjected to dual regulation in response to nitrogen limitation and cyanuric acid. The gene adjacent to atzD, orf99 (renamed here atzR), encoding a LysR-like regulator, was found to be required for both responses. Expression of atzR-lacZ was induced by nitrogen limitation and repressed by AtzR. Nitrogen regulation of atzD-lacZ and atzR-lacZ expression was dependent on the alternative sigma factor sigmaN and NtrC, suggesting that the cyanuric acid degradation operon may be subject to general nitrogen control. However, while atzR is transcribed from a sigmaN-dependent promoter, atzDEF transcription appears to be driven from a sigma70-type promoter. Expression of atzR from a heterologous promoter revealed that although NtrC regulation of atzD-lacZ requires the AtzR protein, it is not the indirect result of NtrC-activated AtzR synthesis. We propose that expression of the cyanuric acid degradation operon atzDEF is controlled by means of a complex regulatory circuit in which AtzR is the main activator. AtzR activity is in turn modulated by the presence of cyanuric acid and by a nitrogen limitation signal transduced by the Ntr system.
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Affiliation(s)
- Vicente García-González
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide, Carretera de Utrera, Km. 1, 41013, Seville, Spain
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McLeod MP, Qin X, Karpathy SE, Gioia J, Highlander SK, Fox GE, McNeill TZ, Jiang H, Muzny D, Jacob LS, Hawes AC, Sodergren E, Gill R, Hume J, Morgan M, Fan G, Amin AG, Gibbs RA, Hong C, Yu XJ, Walker DH, Weinstock GM. Complete genome sequence of Rickettsia typhi and comparison with sequences of other rickettsiae. J Bacteriol 2004; 186:5842-55. [PMID: 15317790 PMCID: PMC516817 DOI: 10.1128/jb.186.17.5842-5855.2004] [Citation(s) in RCA: 165] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2004] [Accepted: 05/17/2004] [Indexed: 11/20/2022] Open
Abstract
Rickettsia typhi, the causative agent of murine typhus, is an obligate intracellular bacterium with a life cycle involving both vertebrate and invertebrate hosts. Here we present the complete genome sequence of R. typhi (1,111,496 bp) and compare it to the two published rickettsial genome sequences: R. prowazekii and R. conorii. We identified 877 genes in R. typhi encoding 3 rRNAs, 33 tRNAs, 3 noncoding RNAs, and 838 proteins, 3 of which are frameshifts. In addition, we discovered more than 40 pseudogenes, including the entire cytochrome c oxidase system. The three rickettsial genomes share 775 genes: 23 are found only in R. prowazekii and R. typhi, 15 are found only in R. conorii and R. typhi, and 24 are unique to R. typhi. Although most of the genes are colinear, there is a 35-kb inversion in gene order, which is close to the replication terminus, in R. typhi, compared to R. prowazekii and R. conorii. In addition, we found a 124-kb R. typhi-specific inversion, starting 19 kb from the origin of replication, compared to R. prowazekii and R. conorii. Inversions in this region are also seen in the unpublished genome sequences of R. sibirica and R. rickettsii, indicating that this region is a hot spot for rearrangements. Genome comparisons also revealed a 12-kb insertion in the R. prowazekii genome, relative to R. typhi and R. conorii, which appears to have occurred after the typhus (R. prowazekii and R. typhi) and spotted fever (R. conorii) groups diverged. The three-way comparison allowed further in silico analysis of the SpoT split genes, leading us to propose that the stringent response system is still functional in these rickettsiae.
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MESH Headings
- Chromosome Inversion
- DNA, Bacterial/chemistry
- DNA, Bacterial/isolation & purification
- Electron Transport Complex IV/genetics
- Frameshifting, Ribosomal
- Gene Expression Regulation, Bacterial
- Gene Rearrangement
- Genes, Bacterial
- Genes, rRNA
- Genome, Bacterial
- Genomics
- Molecular Sequence Data
- Pseudogenes
- RNA, Transfer/genetics
- RNA, Untranslated/genetics
- Rickettsia/genetics
- Rickettsia conorii/genetics
- Rickettsia typhi/genetics
- Sequence Analysis, DNA
- Sequence Homology
- Synteny
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Affiliation(s)
- Michael P McLeod
- Human Genome Sequencing Center, Baylor College of Medicine, One Baylor Plaza, Alkek N1519, Houston, TX 77030-7783, USA
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Hamon MA, Stanley NR, Britton RA, Grossman AD, Lazazzera BA. Identification of AbrB-regulated genes involved in biofilm formation by Bacillus subtilis. Mol Microbiol 2004; 52:847-60. [PMID: 15101989 PMCID: PMC1409746 DOI: 10.1111/j.1365-2958.2004.04023.x] [Citation(s) in RCA: 163] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Bacillus subtilis is a ubiquitous soil bacterium that forms biofilms in a process that is negatively controlled by the transcription factor AbrB. To identify the AbrB-regulated genes required for biofilm formation by B. subtilis, genome-wide expression profiling studies of biofilms formed by spo0A abrB and sigH abrB mutant strains were performed. These data, in concert with previously published DNA microarray analysis of spo0A and sigH mutant strains, led to the identification of 39 operons that appear to be repressed by AbrB. Eight of these operons had previously been shown to be repressed by AbrB, and we confirmed AbrB repression for a further six operons by reverse transcription-PCR. The AbrB-repressed genes identified in this study are involved in processes known to be regulated by AbrB, such as extracellular degradative enzyme production and amino acid metabolism, and processes not previously known to be regulated by AbrB, such as membrane bioenergetics and cell wall functions. To determine whether any of these AbrB-regulated genes had a role in biofilm formation, we tested 23 mutants, each with a disruption in a different AbrB-regulated operon, for the ability to form biofilms. Two mutants had a greater than twofold defect in biofilm formation. A yoaW mutant exhibited a biofilm structure with reduced depth, and a sipW mutant exhibited only surface-attached cells and did not form a mature biofilm. YoaW is a putative secreted protein, and SipW is a signal peptidase. This is the first evidence that secreted proteins have a role in biofilm formation by Bacillus subtilis.
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Affiliation(s)
- Mélanie A. Hamon
- Department of Microbiology, Immunology and Molecular Genetics University of California Los Angeles 1602 Molecular Sciences Building 405 Hilgard Avenue Los Angeles, CA 90095, USA
| | - Nicola R. Stanley
- Department of Microbiology, Immunology and Molecular Genetics University of California Los Angeles 1602 Molecular Sciences Building 405 Hilgard Avenue Los Angeles, CA 90095, USA
| | - Robert A. Britton
- Department of Biology Massachusetts Institute of Technology Cambridge, MA 02139, USA
| | - Alan. D. Grossman
- Department of Biology Massachusetts Institute of Technology Cambridge, MA 02139, USA
| | - Beth A. Lazazzera
- Department of Microbiology, Immunology and Molecular Genetics University of California Los Angeles 1602 Molecular Sciences Building 405 Hilgard Avenue Los Angeles, CA 90095, USA
- *For correspondence. E-mail; Tel (+1) 310 794 4804; Fax (+1) 310 206 5231
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Grammel H, Gilles ED, Ghosh R. Microaerophilic cooperation of reductive and oxidative pathways allows maximal photosynthetic membrane biosynthesis in Rhodospirillum rubrum. Appl Environ Microbiol 2004; 69:6577-86. [PMID: 14602616 PMCID: PMC262267 DOI: 10.1128/aem.69.11.6577-6586.2003] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The purple nonsulfur bacterium Rhodospirillum rubrum has been employed to study physiological adaptation to limiting oxygen tensions (microaerophilic conditions). R. rubrum produces maximal levels of photosynthetic membranes when grown with both succinate and fructose as carbon sources under microaerophilic conditions in comparison to the level (only about 20% of the maximum) seen in the absence of fructose. Employing a unique partial O(2) pressure (pO(2)) control strategy to reliably adjust the oxygen tension to values below 0.5%, we have used bioreactor cultures to investigate the metabolic rationale for this effect. A metabolic profile of the central carbon metabolism of these cultures was obtained by determination of key enzyme activities under microaerophilic as well as aerobic and anaerobic phototrophic conditions. Under aerobic conditions succinate and fructose were consumed simultaneously, whereas oxygen-limiting conditions provoked the preferential breakdown of fructose. Fructose was utilized via the Embden-Meyerhof-Parnas pathway. High levels of pyrophosphate-dependent phosphofructokinase activity were found to be specific for oxygen-limited cultures. No glucose-6-phosphate dehydrogenase activity was detected under any conditions. We demonstrate that NADPH is supplied mainly by the pyridine-nucleotide transhydrogenase under oxygen-limiting conditions. The tricarboxylic acid cycle enzymes are present at significant levels during microaerophilic growth, albeit at lower levels than those seen under fully aerobic growth conditions. Levels of the reductive tricarboxylic acid cycle marker enzyme fumarate reductase were also high under microaerophilic conditions. We propose a model by which the primary "switching" of oxidative and reductive metabolism is performed at the level of the tricarboxylic acid cycle and suggest how this might affect redox signaling and gene expression in R. rubrum.
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Affiliation(s)
- Hartmut Grammel
- Max Planck Institute for Dynamics of Complex Technical Systems, D-39106 Magdeburg, Department of Bioenergetics, Institute for Biology, University of Stuttgart, D-70550 Stuttgart, Germany
- Corresponding author. Mailing address: Max Planck Institute for Dynamics of Complex Technical Systems, Sandtorstr. 1, D-39106 Magdeburg, Germany. Phone: 49-391-6110-255. Fax: 49-391-6110-527. E-mail:
| | - Ernst-Dieter Gilles
- Max Planck Institute for Dynamics of Complex Technical Systems, D-39106 Magdeburg, Department of Bioenergetics, Institute for Biology, University of Stuttgart, D-70550 Stuttgart, Germany
| | - Robin Ghosh
- Max Planck Institute for Dynamics of Complex Technical Systems, D-39106 Magdeburg, Department of Bioenergetics, Institute for Biology, University of Stuttgart, D-70550 Stuttgart, Germany
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48
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Zhang J, Barquera B, Gennis RB. Gene fusions with β-lactamase show that subunit I of the cytochromebdquinol oxidase fromE. colihas nine transmembrane helices with the O2reactive site near the periplasmic surface. FEBS Lett 2004; 561:58-62. [PMID: 15013751 DOI: 10.1016/s0014-5793(04)00125-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2003] [Accepted: 01/09/2004] [Indexed: 11/25/2022]
Abstract
The cytochrome bd quinol oxidase is a component of the respiratory chain of many prokaryotes. The enzyme contains two subunits, CydA and CydB, which were initially predicted based on the sequence of the Escherichia coli oxidase to have seven and eight transmembrane spans, respectively. More recently, the topological model of CydA was revised to predict nine transmembrane helices, based on additional sequence information from other organisms. In the current work, the topology of the E. coli oxidase was experimentally examined using beta-lactamase gene fusions. The results confirm the revised topology, which places the oxygen reactive site near the periplasmic surface.
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Affiliation(s)
- Jie Zhang
- Department of Biochemistry, University of Illinois, 600 South Mathews Street, Urbana, IL 61801, USA.
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49
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Mangan S, Alon U. Structure and function of the feed-forward loop network motif. Proc Natl Acad Sci U S A 2003; 100:11980-5. [PMID: 14530388 PMCID: PMC218699 DOI: 10.1073/pnas.2133841100] [Citation(s) in RCA: 1085] [Impact Index Per Article: 51.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2003] [Indexed: 12/30/2022] Open
Abstract
Engineered systems are often built of recurring circuit modules that carry out key functions. Transcription networks that regulate the responses of living cells were recently found to obey similar principles: they contain several biochemical wiring patterns, termed network motifs, which recur throughout the network. One of these motifs is the feed-forward loop (FFL). The FFL, a three-gene pattern, is composed of two input transcription factors, one of which regulates the other, both jointly regulating a target gene. The FFL has eight possible structural types, because each of the three interactions in the FFL can be activating or repressing. Here, we theoretically analyze the functions of these eight structural types. We find that four of the FFL types, termed incoherent FFLs, act as sign-sensitive accelerators: they speed up the response time of the target gene expression following stimulus steps in one direction (e.g., off to on) but not in the other direction (on to off). The other four types, coherent FFLs, act as sign-sensitive delays. We find that some FFL types appear in transcription network databases much more frequently than others. In some cases, the rare FFL types have reduced functionality (responding to only one of their two input stimuli), which may partially explain why they are selected against. Additional features, such as pulse generation and cooperativity, are discussed. This study defines the function of one of the most significant recurring circuit elements in transcription networks.
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Affiliation(s)
- S Mangan
- Departments of Molecular Cell Biology and Physics of Complex Systems, Weizmann Institute of Science, Rehovot 76100, Israel
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50
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Affiliation(s)
- Peggy A Cotter
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA 93106-9610, USA.
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