1
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Bhat EH, Henard JM, Lee SA, McHalffey D, Ravulapati MS, Rogers EV, Yu L, Skiles D, Henard CA. Construction of a broad-host-range Anderson promoter series and particulate methane monooxygenase promoter variants expand the methanotroph genetic toolbox. Synth Syst Biotechnol 2024; 9:250-258. [PMID: 38435708 PMCID: PMC10909576 DOI: 10.1016/j.synbio.2024.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2024] [Revised: 02/02/2024] [Accepted: 02/06/2024] [Indexed: 03/05/2024] Open
Abstract
Methanotrophic bacteria are currently used industrially for the bioconversion of methane-rich natural gas and anaerobic digestion-derived biogas to valuable products. These bacteria may also serve to mitigate the negative effects of climate change by capturing atmospheric greenhouse gases. Several genetic tools have previously been developed for genetic and metabolic engineering of methanotrophs. However, the available tools for use in methanotrophs are significantly underdeveloped compared to many other industrially relevant bacteria, which hinders genetic and metabolic engineering of these biocatalysts. As such, expansion of the methanotroph genetic toolbox is needed to further our understanding of methanotrophy and develop biotechnologies that leverage these unique microbes for mitigation and conversion of methane to valuable products. Here, we determined the copy number of three broad-host-range plasmids in Methylococcus capsulatus Bath and Methylosinus trichosporium OB3b, representing phylogenetically diverse Gammaproteobacterial and Alphaproteobacterial methanotrophs, respectively. Further, we show that the commonly used synthetic Anderson series promoters are functional and exhibit similar relative activity in M. capsulatus and M. trichosporium OB3b, but the synthetic series had limited range. Thus, we mutagenized the native M. capsulatus particulate methane monooxygenase promoter and identified variants with activity that expand the activity range of synthetic, constitutive promoters functional not only in M. capsulatus, but also in Escherichia coli. Collectively, the tools developed here advance the methanotroph genetic engineering toolbox and represent additional synthetic genetic parts that may have broad applicability in Pseudomonadota bacteria.
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Affiliation(s)
| | | | | | - Dustin McHalffey
- Department of Biological Sciences and BioDiscovery Institute, University of North Texas, Denton, TX, USA
| | - Mahith S. Ravulapati
- Department of Biological Sciences and BioDiscovery Institute, University of North Texas, Denton, TX, USA
| | - Elle V. Rogers
- Department of Biological Sciences and BioDiscovery Institute, University of North Texas, Denton, TX, USA
| | - Logan Yu
- Department of Biological Sciences and BioDiscovery Institute, University of North Texas, Denton, TX, USA
| | - David Skiles
- Department of Biological Sciences and BioDiscovery Institute, University of North Texas, Denton, TX, USA
| | - Calvin A. Henard
- Department of Biological Sciences and BioDiscovery Institute, University of North Texas, Denton, TX, USA
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2
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Nath S, Henard JM, Henard CA. Optimized Tools and Methods for Methanotroph Genome Editing. Methods Mol Biol 2022; 2489:421-434. [PMID: 35524062 DOI: 10.1007/978-1-0716-2273-5_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Microbes with the capacity to use methane (CH4) as a carbon source (methanotrophs) have significant potential for the bioconversion of CH4-containing natural gas and anaerobic digestion-derived biogas to high value products. These organisms also play a vital role in the biogeochemical cycling of atmospheric CH4 by serving as the only known biological sink of this gas in terrestrial and aquatic ecosystems. Much is known regarding the enzymes and central metabolic pathways mediating CH4 utilization in these bacteria. However, large fundamental knowledge gaps exist regarding methanotroph physiology and responses to environmental stimuli, primarily due to a lack of efficient molecular tools to probe gene-function relationships. In this chapter, we describe several recently developed genetic tools and optimized genome editing methods that can be used for methanotroph metabolic engineering and to probe metabolic and physiological governing mechanisms in these unique bacteria.
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Affiliation(s)
- Sreemoye Nath
- Department of Biological Sciences, University of North Texas, Denton, TX, USA
- BioDiscovery Institute, University of North Texas, Denton, TX, USA
| | - Jessica M Henard
- BioDiscovery Institute, University of North Texas, Denton, TX, USA
| | - Calvin A Henard
- Department of Biological Sciences, University of North Texas, Denton, TX, USA.
- BioDiscovery Institute, University of North Texas, Denton, TX, USA.
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3
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Xiong W, Kalyuzhnaya MG, Henard CA. Editorial: Microbial C1 Metabolism and Biotechnology. Front Microbiol 2021; 12:744030. [PMID: 34512617 PMCID: PMC8429839 DOI: 10.3389/fmicb.2021.744030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 07/30/2021] [Indexed: 11/30/2022] Open
Affiliation(s)
- Wei Xiong
- National Renewable Energy Laboratory, Biosciences Center, Golden, CO, United States
| | | | - Calvin A Henard
- Department of Biological Sciences and BioDiscovery Institute, University of North Texas, Denton, TX, United States
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4
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Fei Q, Liang B, Tao L, Tan EC, Gonzalez R, Henard CA, Guarnieri MT. Biological valorization of natural gas for the production of lactic acid: Techno-economic analysis and life cycle assessment. Biochem Eng J 2020. [DOI: 10.1016/j.bej.2020.107500] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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5
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Dahlin LR, Gerritsen AT, Henard CA, Van Wychen S, Linger JG, Kunde Y, Hovde BT, Starkenburg SR, Posewitz MC, Guarnieri MT. Development of a high-productivity, halophilic, thermotolerant microalga Picochlorum renovo. Commun Biol 2019; 2:388. [PMID: 31667362 PMCID: PMC6811619 DOI: 10.1038/s42003-019-0620-2] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 09/10/2019] [Indexed: 01/21/2023] Open
Abstract
Microalgae are promising biocatalysts for applications in sustainable fuel, food, and chemical production. Here, we describe culture collection screening, down-selection, and development of a high-productivity, halophilic, thermotolerant microalga, Picochlorum renovo. This microalga displays a rapid growth rate and high diel biomass productivity (34 g m-2 day-1), with a composition well-suited for downstream processing. P. renovo exhibits broad salinity tolerance (growth at 107.5 g L-1 salinity) and thermotolerance (growth up to 40 °C), beneficial traits for outdoor cultivation. We report complete genome sequencing and analysis, and genetic tool development suitable for expression of transgenes inserted into the nuclear or chloroplast genomes. We further evaluate mechanisms of halotolerance via comparative transcriptomics, identifying novel genes differentially regulated in response to high salinity cultivation. These findings will enable basic science inquiries into control mechanisms governing Picochlorum biology and lay the foundation for development of a microalga with industrially relevant traits as a model photobiology platform.
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Affiliation(s)
- Lukas R. Dahlin
- Department of Chemistry, Colorado School of Mines, Golden, CO 80401 USA
| | - Alida T. Gerritsen
- Computational Science Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Calvin A. Henard
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Stefanie Van Wychen
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Jeffrey G. Linger
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Yuliya Kunde
- Los Alamos National Laboratory, Los Alamos, NM 87545 USA
| | - Blake T. Hovde
- Los Alamos National Laboratory, Los Alamos, NM 87545 USA
| | | | | | - Michael T. Guarnieri
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
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6
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Qian F, Zhu C, Knipe JM, Ruelas S, Stolaroff JK, DeOtte JR, Duoss EB, Spadaccini CM, Henard CA, Guarnieri MT, Baker SE. Direct Writing of Tunable Living Inks for Bioprocess Intensification. Nano Lett 2019; 19:5829-5835. [PMID: 30702295 DOI: 10.1021/acs.nanolett.9b00066] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Critical to the success of three-dimensional (3D) printing of living materials with high performance is the development of new ink materials and 3D geometries that favor long-term cell functionality. Here we report the use of freeze-dried live cells as the solid filler to enable a new living material system for direct ink writing of catalytically active microorganisms with tunable densities and various self-supporting porous 3D geometries. Baker's yeast was used as an exemplary live whole-cell biocatalyst, and the printed structures displayed high resolution, large scale, high catalytic activity and long-term viability. An unprecedented high cell loading was achieved, and cell inks showed unique thixotropic behavior. In the presence of glucose, printed bioscaffolds exhibited increased ethanol production compared to bulk counterparts due largely to improved mass transfer through engineered porous structures. The new living materials developed in this work could serve as a versatile platform for process intensification of an array of bioconversion processes utilizing diverse microbial biocatalysts for production of high-value products or bioremediation applications.
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Affiliation(s)
| | | | | | | | | | - Joshua R DeOtte
- University of California , Davis , California 95616 , United States
| | | | | | - Calvin A Henard
- National Bioenergy Center , National Renewable Energy Laboratory , Golden , Colorado 80401 , United States
| | - Michael T Guarnieri
- National Bioenergy Center , National Renewable Energy Laboratory , Golden , Colorado 80401 , United States
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7
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Henard CA, Franklin TG, Youhenna B, But S, Alexander D, Kalyuzhnaya MG, Guarnieri MT. Biogas Biocatalysis: Methanotrophic Bacterial Cultivation, Metabolite Profiling, and Bioconversion to Lactic Acid. Front Microbiol 2018; 9:2610. [PMID: 30429839 PMCID: PMC6220066 DOI: 10.3389/fmicb.2018.02610] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 10/12/2018] [Indexed: 12/19/2022] Open
Abstract
Anaerobic digestion (AD) of waste substrates, and renewable biomass and crop residues offers a means to generate energy-rich biogas. However, at present, AD-derived biogas is primarily flared or used for combined heat and power (CHP), in part due to inefficient gas-to-liquid conversion technologies. Methanotrophic bacteria are capable of utilizing methane as a sole carbon and energy source, offering promising potential for biological gas-to-liquid conversion of AD-derived biogas. Here, we report cultivation of three phylogenetically diverse methanotrophic bacteria on biogas streams derived from AD of a series of energy crop residues. Strains maintained comparable central metabolic activity and displayed minimal growth inhibition when cultivated under batch configuration on AD biogas streams relative to pure methane, although metabolite analysis suggested biogas streams increase cellular oxidative stress. In contrast to batch cultivation, growth arrest was observed under continuous cultivation configuration, concurrent with increased biosynthesis and excretion of lactate. We examined the potential for enhanced lactate production via the employ of a pyruvate dehydrogenase mutant strain, ultimately achieving 0.027 g lactate/g DCW/h, the highest reported lactate specific productivity from biogas to date.
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Affiliation(s)
- Calvin A Henard
- National Renewable Energy Laboratory, National Bioenergy Center, Golden, CO, United States
| | - Tyler G Franklin
- National Renewable Energy Laboratory, National Bioenergy Center, Golden, CO, United States
| | - Batool Youhenna
- Biology Department, San Diego State University, San Diego, CA, United States
| | - Sergey But
- Skryabin Institute of Biochemistry and Physiology of Microorganisms, Moscow, Russia
| | | | | | - Michael T Guarnieri
- National Renewable Energy Laboratory, National Bioenergy Center, Golden, CO, United States
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8
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Shaw JA, Henard CA, Liu L, Dieckman LM, Vázquez-Torres A, Bourret TJ. Salmonella enterica serovar Typhimurium has three transketolase enzymes contributing to the pentose phosphate pathway. J Biol Chem 2018; 293:11271-11282. [PMID: 29848552 DOI: 10.1074/jbc.ra118.003661] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 05/23/2018] [Indexed: 11/06/2022] Open
Abstract
The genus Salmonella is responsible for many illnesses in humans and other vertebrate animals. We report here that Salmonella enterica serovar Typhimurium harbors three transketolases that support the non-oxidative branch of the pentose phosphate pathway. BLAST analysis identified two genes, STM14_2885 and STM14_2886, that together encode a putative transketolase (TktC) with 46-47% similarity to the known TktA and TktB isoforms. Assessing the mRNA and protein expression for each of the three transketolases, we determined that all are expressed in WT cells and regulated to varying extents by the alternative sigma factor RpoS. Enzyme assays with lysates from WT and transketolase-knockout strains established that TktA is responsible for >88% of the transketolase activity in WT cells. We purified recombinant forms of each isoenzyme to assess the kinetics for canonical transketolase reactions. TktA and TktB had comparable values for Vmax (539-1362 μm NADH consumed/s), Km (80-739 μm), and catalytic efficiency (1.02 × 108-1.06 × 109 m-1/s) for each substrate tested. The recombinant form of TktC had lower Km values (23-120 μm), whereas the Vmax (7.8-16 μm NADH consumed/s) and catalytic efficiency (5.58 × 106 to 6.07 × 108 m-1/s) were 10-100-fold lower. Using a murine model of Salmonella infection, we showed that a strain lacking all three transketolases is avirulent in C57BL/6 mice. These data provide evidence that S Typhimurium possesses three transketolases that contribute to pathogenesis.
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Affiliation(s)
- Jeff A Shaw
- Department of Medical Microbiology and Immunology, Creighton University School of Medicine, Omaha, Nebraska 68178
| | - Calvin A Henard
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado 80011
| | - Lin Liu
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado 80011
| | - Lynne M Dieckman
- Department of Chemistry, Creighton University, Omaha, Nebraska 68178
| | - Andrés Vázquez-Torres
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado 80011; Veterans Affairs Eastern Colorado Health Care System, Denver, Colorado 80220
| | - Travis J Bourret
- Department of Medical Microbiology and Immunology, Creighton University School of Medicine, Omaha, Nebraska 68178.
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9
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Freed E, Fenster J, Smolinski SL, Walker J, Henard CA, Gill R, Eckert CA. Building a genome engineering toolbox in nonmodel prokaryotic microbes. Biotechnol Bioeng 2018; 115:2120-2138. [PMID: 29750332 DOI: 10.1002/bit.26727] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 04/02/2018] [Accepted: 03/10/2018] [Indexed: 12/26/2022]
Abstract
The realization of a sustainable bioeconomy requires our ability to understand and engineer complex design principles for the development of platform organisms capable of efficient conversion of cheap and sustainable feedstocks (e.g., sunlight, CO2 , and nonfood biomass) into biofuels and bioproducts at sufficient titers and costs. For model microbes, such as Escherichia coli, advances in DNA reading and writing technologies are driving the adoption of new paradigms for engineering biological systems. Unfortunately, microbes with properties of interest for the utilization of cheap and renewable feedstocks, such as photosynthesis, autotrophic growth, and cellulose degradation, have very few, if any, genetic tools for metabolic engineering. Therefore, it is important to develop "design rules" for building a genetic toolbox for novel microbes. Here, we present an overview of our current understanding of these rules for the genetic manipulation of prokaryotic microbes and the available genetic tools to expand our ability to genetically engineer nonmodel systems.
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Affiliation(s)
- Emily Freed
- National Renewable Energy Laboratory, Biosciences Center, Golden, CO.,Renewable and Sustainable Energy Institute, University of Colorado, Boulder, CO
| | - Jacob Fenster
- Renewable and Sustainable Energy Institute, University of Colorado, Boulder, CO.,Chemical and Biological Engineering, University of Colorado, Boulder, CO
| | | | - Julie Walker
- Renewable and Sustainable Energy Institute, University of Colorado, Boulder, CO
| | - Calvin A Henard
- National Renewable Energy Laboratory, National Bioenergy Center, Golden, CO
| | - Ryan Gill
- National Renewable Energy Laboratory, Biosciences Center, Golden, CO.,Renewable and Sustainable Energy Institute, University of Colorado, Boulder, CO.,Chemical and Biological Engineering, University of Colorado, Boulder, CO
| | - Carrie A Eckert
- National Renewable Energy Laboratory, Biosciences Center, Golden, CO.,Renewable and Sustainable Energy Institute, University of Colorado, Boulder, CO
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10
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Guarnieri MT, Levering J, Henard CA, Boore JL, Betenbaugh MJ, Zengler K, Knoshaug EP. Genome Sequence of the Oleaginous Green Alga, Chlorella vulgaris UTEX 395. Front Bioeng Biotechnol 2018; 6:37. [PMID: 29675409 PMCID: PMC5895722 DOI: 10.3389/fbioe.2018.00037] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 03/19/2018] [Indexed: 11/13/2022] Open
Affiliation(s)
- Michael T Guarnieri
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Jennifer Levering
- Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, University of California, San Diego, La Jolla, CA, United States
| | - Calvin A Henard
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, United States
| | | | - Michael J Betenbaugh
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD, United States
| | - Karsten Zengler
- Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, University of California, San Diego, La Jolla, CA, United States
| | - Eric P Knoshaug
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, United States
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11
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Guarnieri MT, Gerritsen AT, Henard CA, Knoshaug EP. Phosphoproteome of the Oleaginous Green Alga, Chlorella vulgaris UTEX 395, under Nitrogen-Replete and -Deplete Conditions. Front Bioeng Biotechnol 2018; 6:19. [PMID: 29560349 PMCID: PMC5845665 DOI: 10.3389/fbioe.2018.00019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 02/12/2018] [Indexed: 11/30/2022] Open
Affiliation(s)
- Michael T Guarnieri
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Alida T Gerritsen
- Computational Science Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Calvin A Henard
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Eric P Knoshaug
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, United States
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12
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Henard CA, Smith HK, Guarnieri MT. Phosphoketolase overexpression increases biomass and lipid yield from methane in an obligate methanotrophic biocatalyst. Metab Eng 2017; 41:152-158. [DOI: 10.1016/j.ymben.2017.03.007] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 02/17/2017] [Accepted: 03/31/2017] [Indexed: 12/20/2022]
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13
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Henard CA, Guarnieri MT, Knoshaug EP. The Chlorella vulgaris S-Nitrosoproteome under Nitrogen-Replete and -Deplete Conditions. Front Bioeng Biotechnol 2017; 4:100. [PMID: 28144611 PMCID: PMC5239800 DOI: 10.3389/fbioe.2016.00100] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 12/27/2016] [Indexed: 01/12/2023] Open
Affiliation(s)
- Calvin A Henard
- National Bioenergy Center, National Renewable Energy Laboratory , Golden, CO , USA
| | - Michael T Guarnieri
- National Bioenergy Center, National Renewable Energy Laboratory , Golden, CO , USA
| | - Eric P Knoshaug
- National Bioenergy Center, National Renewable Energy Laboratory , Golden, CO , USA
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14
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Crawford MA, Henard CA, Tapscott T, Porwollik S, McClelland M, Vázquez-Torres A. DksA-Dependent Transcriptional Regulation in Salmonella Experiencing Nitrosative Stress. Front Microbiol 2016; 7:444. [PMID: 27065993 PMCID: PMC4815678 DOI: 10.3389/fmicb.2016.00444] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 03/18/2016] [Indexed: 01/12/2023] Open
Abstract
Redox-based signaling is fundamental to the capacity of bacteria to sense, and respond to, nitrosative and oxidative stress encountered in natural and host environments. The conserved RNA polymerase regulatory protein DksA is a thiol-based sensor of reactive nitrogen and oxygen species. DksA-dependent transcriptional control promotes antinitrosative and antioxidative defenses that contribute to Salmonella pathogenesis. The specific adaptive changes mediated by DksA in response to reactive species, however, have not been elucidated. Herein, we characterize DksA-dependent changes in gene expression in Salmonella enterica experiencing nitrosative stress. Genome-wide expression analysis of wild-type and ΔdksA Salmonella exposed to the nitric oxide (•NO) donor DETA NONOate demonstrated •NO- and DksA-dependent regulatory control of 427 target genes. Transcriptional changes centered primarily on genes encoding aspects of cellular metabolism. Several antioxidants and oxidoreductases important in redox buffering, •NO detoxification, and damage repair were also observed to be up-regulated in an •NO- and DksA-dependent manner. Compared to wild-type bacteria, •NO-treated ΔdksA Salmonella exhibited a de-repression of genes encoding components of iron homeostasis and failed to activate sulfur assimilation and cysteine biosynthetic operons. As cysteine is integral to efficient antinitrosative and antioxidative defense and repair programs, we further examined the redox-responsive transcriptional control of cysteine biosynthesis by DksA. These investigations revealed that the activation of genes comprising cysteine biosynthesis also occurs in response to hydrogen peroxide, is dependent upon the redox-sensing zinc finger motif of DksA, and requires the transcriptional regulator CysB. Our observations demonstrate that DksA mediates global adaptation to nitrosative stress in Salmonella and provide unique insight into a novel regulatory mechanism by which cysteine biosynthesis is controlled in response to reactive oxygen and nitrogen species.
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Affiliation(s)
- Matthew A Crawford
- Department of Immunology and Microbiology, University of Colorado School of Medicine Aurora, CO, USA
| | - Calvin A Henard
- Department of Immunology and Microbiology, University of Colorado School of Medicine Aurora, CO, USA
| | - Timothy Tapscott
- Molecular Biology Program, University of Colorado School of Medicine Aurora, CO, USA
| | - Steffen Porwollik
- Department of Pathology and Laboratory Medicine, University of California, Irvine Irvine, CA, USA
| | - Michael McClelland
- Department of Pathology and Laboratory Medicine, University of California, Irvine Irvine, CA, USA
| | - Andrés Vázquez-Torres
- Department of Immunology and Microbiology, University of Colorado School of MedicineAurora, CO, USA; Veterans Affairs Eastern Colorado Health Care SystemDenver, CO, USA
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15
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Carlsen ED, Jie Z, Liang Y, Henard CA, Hay C, Sun J, de Matos Guedes H, Soong L. Interactions between Neutrophils and Leishmania braziliensis Amastigotes Facilitate Cell Activation and Parasite Clearance. J Innate Immun 2015; 7:354-63. [PMID: 25766649 PMCID: PMC4485586 DOI: 10.1159/000373923] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Revised: 01/08/2015] [Accepted: 01/08/2015] [Indexed: 01/14/2023] Open
Abstract
Leishmania braziliensis and Leishmania amazonensis are both causative agents of cutaneous leishmaniasis in South America. However, patient prognosis and the host immune response differ considerably depending on the infecting parasite species. The mechanisms underlying these differences appear to be multifactorial, with both host and parasite components contributing to disease outcome. As neutrophils are a prominent component of the inflammatory infiltrate in chronic cutaneous, diffuse cutaneous and mucocutaneous lesions, we examined neutrophil activation and microbicidal activity against amastigotes of L. amazonensis and L. braziliensis. We found that murine neutrophils internalized L. braziliensis amastigotes with greater efficiency than did L. amazonensis amastigotes. Additionally, L. braziliensis infection was a potent trigger for neutrophil activation, oxidative burst, degranulation and the production of interleukin (IL)-22 and IL-10, while L. amazonensis amastigotes poorly induced these responses. Finally, neutrophils were able to kill L. braziliensis amastigotes, especially when cells were activated with phorbol myristate acetate. L. amazonensis amastigotes, however, were highly resistant to neutrophil microbicidal mechanisms. This study reveals, for the first time, differential neutrophil responsiveness to distinct species of Leishmania amastigotes and highlights the complexity of neutrophil-amastigote interactions during chronic leishmaniasis.
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Affiliation(s)
- Eric D. Carlsen
- MD-PhD Combined Degree Program, University of Texas Medical Branch, Galveston, Tex., USA
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Tex., USA
| | - Zuliang Jie
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Tex., USA
| | - Yuejin Liang
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Tex., USA
| | - Calvin A. Henard
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Tex., USA
| | - Christie Hay
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Tex., USA
| | - Jiaren Sun
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Tex., USA
| | - Herbert de Matos Guedes
- Laboratório de Inflamação, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Polo avançado de Xerém, Rio de Janeiro, Brazil
| | - Lynn Soong
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Tex., USA
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Henard CA, Carlsen ED, Hay C, Kima PE, Soong L. Leishmania amazonensis amastigotes highly express a tryparedoxin peroxidase isoform that increases parasite resistance to macrophage antimicrobial defenses and fosters parasite virulence. PLoS Negl Trop Dis 2014; 8:e3000. [PMID: 25033301 PMCID: PMC4102420 DOI: 10.1371/journal.pntd.0003000] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 05/31/2014] [Indexed: 12/21/2022] Open
Abstract
Professional phagocytes generate a myriad of antimicrobial molecules to kill invading microorganisms, of which nitrogen oxides are integral in controlling the obligate intracellular pathogen Leishmania. Although reactive nitrogen species produced by the inducible nitric oxide synthase (iNOS) can promote the clearance of intracellular parasites, some Leishmania species/stages are relatively resistant to iNOS-mediated antimicrobial activity. The underlying mechanism for this resistance remains largely uncharacterized. Here, we show that the amastigote form of L. amazonensis is hyper-resistant to the antimicrobial actions of cytokine-activated murine and human macrophages as compared to its promastigote counterpart. Amastigotes exhibit a marked ability to directly counter the cytotoxicity of peroxynitrite (ONOO−), a leishmanicidal oxidant that is generated during infection through the combined enzymatic activities of NADPH oxidase and iNOS. The enhanced antinitrosative defense of amastigotes correlates with the increased expression of a tryparedoxin peroxidase (TXNPx) isoform that is also upregulated in response to iNOS enzymatic activity within infected macrophages. Accordingly, ectopic over-expression of the TXNPx isoform by L. amazonensis promastigotes significantly enhances parasite resistance against ONOO− cytotoxicity. Moreover, TXNPx-overexpressing parasites exhibit greater intra-macrophage survival, and increased parasite growth and lesion development in a murine model of leishmaniasis. Our investigations indicate that TXNPx isoforms contribute to Leishmania's ability to adapt to and antagonize the hostile microenvironment of cytokine-activated macrophages, and provide a mechanistic explanation for persistent infection in experimental and human leishmaniasis. Pathogens of the genus Leishmania are the causative agents of leishmaniasis, a neglected tropical disease responsible for significant morbidity and mortality worldwide. Although it is well accepted that host-derived leishmanicidal molecules mediate resolution of Leishmania infection, some Leishmania species/stages are relatively resistant to host cell antimicrobial activity. These intracellular pathogens have developed evasive strategies to subvert host antimicrobials, and promote pathogen survival within the harsh intracellular environment. However, the underlying mechanisms remain largely uncharacterized. Here, we show that L. amazonensis, an agent of persistent infection in humans and non-healing skin lesions in mice, antagonize macrophage antimicrobial activity. The superb ability of the amastigote form to survive within host cells is related to its increased expression of a tryparedoxin peroxidase isoform that confers resistance to the cytotoxicity of host-derived antimicrobial molecules. Parasites induce higher expression of the TXNPx in response to iNOS activity during infection of macrophages, indicating that parasites can “sense” the microenvironment of host cells and regulate the expression of relevant virulence factors accordingly. Our investigations are consistent with a model by which Leishmania amastigotes utilize TXNPx to defend against host-derived molecules thereby promoting their intracellular survival and persistent infection.
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Affiliation(s)
- Calvin A. Henard
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Eric D. Carlsen
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas, United States of America
- M.D.-Ph.D. Combined Degree Program, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Christie Hay
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Peter E. Kima
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, United States of America
| | - Lynn Soong
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas, United States of America
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
- * E-mail:
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Henard CA, Tapscott T, Crawford MA, Husain M, Doulias PT, Porwollik S, Liu L, McClelland M, Ischiropoulos H, Vázquez-Torres A. The 4-cysteine zinc-finger motif of the RNA polymerase regulator DksA serves as a thiol switch for sensing oxidative and nitrosative stress. Mol Microbiol 2014; 91:790-804. [PMID: 24354846 DOI: 10.1111/mmi.12498] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/17/2013] [Indexed: 02/03/2023]
Abstract
We show that thiols in the 4-cysteine zinc-finger motif of DksA, an RNA polymerase accessory protein known to regulate the stringent response, sense oxidative and nitrosative stress. Hydrogen peroxide- or nitric oxide (NO)-mediated modifications of thiols in the DksA 4-cysteine zinc-finger motif release the metal cofactor and drive reversible changes in the α-helicity of the protein. Wild-type and relA spoT mutant Salmonella, but not isogenic dksA-deficient bacteria, experience the downregulation of r-protein and amino acid transport expression after NO treatment, suggesting that DksA can regulate gene expression in response to NO congeners independently of the ppGpp alarmone. Oxidative stress enhances the DksA-dependent repression of rpsM, while preventing the activation of livJ and hisG gene transcription that is supported by reduced, zinc-bound DksA. The inhibitory effects of oxidized DksA on transcription are reversible with dithiothreitol. Our investigations indicate that sensing of reactive species by DksA redox active thiols fine-tunes the expression of translational machinery and amino acid assimilation and biosynthesis in accord with the metabolic stress imposed by oxidative and nitrosative stress. Given the conservation of Cys(114) , and neighbouring hydrophobic and charged amino acids in DksA orthologues, phylogenetically diverse microorganisms may use the DksA thiol switch to regulate transcriptional responses to oxidative and nitrosative stress.
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Affiliation(s)
- Calvin A Henard
- Department of Microbiology, University of Colorado School of Medicine, Aurora, CO, USA
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Song M, Husain M, Jones-Carson J, Liu L, Henard CA, Vázquez-Torres A. Low-molecular-weight thiol-dependent antioxidant and antinitrosative defences in Salmonella pathogenesis. Mol Microbiol 2012; 87:609-22. [PMID: 23217033 DOI: 10.1111/mmi.12119] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/02/2012] [Indexed: 12/22/2022]
Abstract
We found herein that the intracytoplasmic pool of the low-molecular-weight (LMW) thiol glutathione (GSH) is readily oxidized in Salmonella exposed to nitric oxide (NO). The hypersusceptibility of gshA and gshB mutants lacking γ-glutamylcysteine and glutathione synthetases to NO and S-nitrosoglutathione indicates that GSH antagonizes the bacteriostatic activity of reactive nitrogen species. Metabolites of the GSH biosynthetic pathway do not affect the enzymatic activity of classical NO targets such as quinol oxidases. In contrast, LMW thiols diminish the nitrosative stress experienced by enzymes, such as glutamine oxoglutarate amidotransferase, that contain redox active cysteines. LMW thiols also preserve the transcription of Salmonella pathogenicity island 2 gene targets from the inhibitory activity of nitrogen oxides. These findings are consistent with the idea that GSH scavenges reactive nitrogen species (RNS) other than NO. Compared with the adaptive response afforded by inducible systems such as the hmp-encoded flavohaemoprotein, gshA, encoding the first step of GSH biosynthesis, is constitutively expressed in Salmonella. An acute model of salmonellosis has revealed that the antioxidant and antinitrosative properties associated with the GSH biosynthetic pathway represent a first line of Salmonella resistance against reactive oxygen and nitrogen species engendered in the context of a functional NRAMP1(R) divalent metal transporter.
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Affiliation(s)
- Miryoung Song
- Department of Microbiology, University of Colorado School of Medicine, Aurora, CO 80045, USA
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Abstract
Nitric oxide (NO) and its congeners contribute to the innate immune response to Salmonella. This enteric pathogen is exposed to reactive nitrogen species (RNS) in the environment and at different anatomical locations during its infectious cycle in vertebrate hosts. Chemical generation of RNS enhances the gastric barrier to enteropathogenic bacteria, while products of the Salmonella pathogenicity island 1 type III secretion system and Salmonella-associated molecular patterns stimulate transcription of inducible NO synthase (iNOS) by cells of the mononuclear phagocytic cell lineage. The resulting NO, or products that arise from its interactions with oxygen (O2) or iron and low-molecular weight thiols, are preferentially bacteriostatic against Salmonella, while reaction of NO and superoxide (O2−) generates the bactericidal compound peroxynitrite (ONOO−). The anti-Salmonella activity of RNS emanates from the modification of redox active thiols and metal prosthetic groups of key molecular targets of the electron transport chain, central metabolic enzymes, transcription factors, and DNA and DNA-associated proteins. In turn, Salmonella display a plethora of defenses that modulate the delivery of iNOS-containing vesicles to phagosomes, scavenge and detoxify RNS, and repair biomolecules damaged by these toxic species. Traditionally, RNS have been recognized as important mediators of host defense against Salmonella. However, exciting new findings indicate that Salmonella can exploit the RNS produced during the infection to foster virulence. More knowledge of the primary RNS produced in response to Salmonella infection, the bacterial processes affected by these toxic species, and the adaptive bacterial responses that protect Salmonella from nitrosative and oxidative stress associated with NO will increase our understanding of Salmonella pathogenesis. This information may assist in the development of novel therapeutics against this common enteropathogen.
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Affiliation(s)
- Calvin A Henard
- Department of Microbiology, University of Colorado School of Medicine Aurora, CO, USA
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Henard CA, Bourret TJ, Song M, Vázquez-Torres A. Control of redox balance by the stringent response regulatory protein promotes antioxidant defenses of Salmonella. J Biol Chem 2010; 285:36785-93. [PMID: 20851888 DOI: 10.1074/jbc.m110.160960] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
We report herein a critical role for the stringent response regulatory DnaK suppressor protein (DksA) in the coordination of antioxidant defenses. DksA helps fine-tune the expression of glutathione biosynthetic genes and discrete steps in the pentose phosphate pathway and tricarboxylic acid cycle that are associated with the generation of reducing power. Control of NAD(P)H/NAD(P)(+) redox balance by DksA fuels downstream antioxidant enzymatic systems in nutritionally starving Salmonella. Conditional expression of the glucose-6-phosphate dehydrogenase-encoding gene zwf, shown here to be under DksA control, increases both the NADPH pool and antioxidant defenses of dksA mutant Salmonella. The DksA-mediated coordination of redox balance boosts the antioxidant defenses of stationary phase bacteria. Not only does DksA increase resistance of Salmonella against hydrogen peroxide (H(2)O(2)), but it also promotes fitness of this intracellular pathogen when exposed to oxyradicals produced by the NADPH phagocyte oxidase in an acute model of infection. Given the role of DksA in the adjustment of gene expression in most bacteria undergoing nutritional deprivation, our findings raise the possibility that the control of central metabolic pathways by this regulatory protein maintains redox homeostasis essential for antioxidant defenses in phylogenetically diverse bacterial species.
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Affiliation(s)
- Calvin A Henard
- Department of Microbiology, Anschutz Medical Center, School of Medicine, University of Colorado, Aurora, Colorado 80045, USA
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Phillips CD, Henard CA, Pfau RS. Amplified Fragment Length Polymorphism and Mitochondrial DNA Analyses Reveal Patterns of Divergence and Hybridization in the Hispid Cotton Rat (Sigmodon hispidus). J Mammal 2007. [DOI: 10.1644/06-mamm-a-089r1.1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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