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Zhang Y, Kubiak AM, Bailey TS, Claessen L, Hittmeyer P, Dubois L, Theys J, Lambin P. Development of a CRISPR-Cas12a system for efficient genome engineering in clostridia. Microbiol Spectr 2023; 11:e0245923. [PMID: 37947521 PMCID: PMC10715149 DOI: 10.1128/spectrum.02459-23] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 07/13/2023] [Indexed: 11/12/2023] Open
Abstract
IMPORTANCE Continued efforts in developing the CRISPR-Cas systems will further enhance our understanding and utilization of Clostridium species. This study demonstrates the development and application of a genome-engineering tool in two Clostridium strains, Clostridium butyricum and Clostridium sporogenes, which have promising potential as probiotics and oncolytic agents. Particular attention was given to the folding of precursor crRNA and the role of this process in off-target DNA cleavage by Cas12a. The results provide the guidelines necessary for efficient genome engineering using this system in clostridia. Our findings not only expand our fundamental understanding of genome-engineering tools in clostridia but also improve this technology to allow use of its full potential in a plethora of biotechnological applications.
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Affiliation(s)
- Yanchao Zhang
- M-Lab, Department of Precision Medicine, GROW - School of Oncology and Reproduction, Maastricht University, Maastricht, The Netherlands
| | - Aleksandra M. Kubiak
- M-Lab, Department of Precision Medicine, GROW - School of Oncology and Reproduction, Maastricht University, Maastricht, The Netherlands
- Exomnis Biotech BV, Maastricht, The Netherlands
| | - Tom S. Bailey
- M-Lab, Department of Precision Medicine, GROW - School of Oncology and Reproduction, Maastricht University, Maastricht, The Netherlands
| | - Luuk Claessen
- M-Lab, Department of Precision Medicine, GROW - School of Oncology and Reproduction, Maastricht University, Maastricht, The Netherlands
- LivingMed Biotech SRL, Liège, Belgium
| | - Philip Hittmeyer
- M-Lab, Department of Precision Medicine, GROW - School of Oncology and Reproduction, Maastricht University, Maastricht, The Netherlands
- LivingMed Biotech SRL, Liège, Belgium
| | - Ludwig Dubois
- M-Lab, Department of Precision Medicine, GROW - School of Oncology and Reproduction, Maastricht University, Maastricht, The Netherlands
| | - Jan Theys
- M-Lab, Department of Precision Medicine, GROW - School of Oncology and Reproduction, Maastricht University, Maastricht, The Netherlands
| | - Philippe Lambin
- M-Lab, Department of Precision Medicine, GROW - School of Oncology and Reproduction, Maastricht University, Maastricht, The Netherlands
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Wu CM, Li LH, Lin YL, Wu CJ, Lin YT, Yang TC. The sbiTRS Operon Contributes to Stenobactin-Mediated Iron Utilization in Stenotrophomonas maltophilia. Microbiol Spectr 2022; 10:e0267322. [PMID: 36453931 PMCID: PMC9769818 DOI: 10.1128/spectrum.02673-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 11/17/2022] [Indexed: 12/03/2022] Open
Abstract
Iron is an essential micronutrient for various bacterial cellular processes. Fur is a global transcriptional regulator participating in iron homeostasis. Stenotrophomonas maltophilia is a ubiquitous environmental bacterium that has emerged as an opportunistic pathogen. To elucidate the novel regulatory mechanism behind iron homeostasis in S. maltophilia, wild-type KJ and KJΔFur, a fur mutant, were subjected to transcriptome assay. A five-gene cluster, sbiBA-sbiTRS, was significantly upregulated in KJΔFur. SbiAB is an ATP type efflux pump, SbiT is an inner membrane protein, and SbiSR is a two-component regulatory system (TCS). The sbiTRS operon organization was verified by reverse transcription-PCR (RT-PCR). Localization prediction and bacterial two-hybrid studies revealed that SbiT resided in the inner membrane and had an intramembrane interaction with SbiS. In iron-replete conditions, SbiT interacted with SbiS and maintained SbiSR TCS in a resting state. In response to iron depletion stress, SbiT no longer interacted with SbiS, leading to SbiSR TCS activation. The iron source utilization assay demonstrated the contribution of SbiSR TCS to stenobactin-mediated ferric iron utilization but notto the utilization of hemin and ferric citrate. Furthermore, SmeDEF and SbiAB pumps, known stenobactin secretion outlets, were members of the SbiSR regulon. Collectively, in an iron-depleted condition, SbiSR activation is regulated by Fur at the transcriptional level and by SbiT at the posttranslational level. Activated SbiSR contributes to stenobactin-mediated ferric iron utilization by upregulating the smeDEF and sbiAB operons. SbiSR is the first TCS found to be involved in iron homeostasis in S. maltophilia. IMPORTANCE Therapeutic options for Stenotrophomonas maltophilia infections are limited because S. maltophilia is intrinsically resistant to several antibiotics. Iron is an essential element for viability, but iron overload is a lethal threat to bacteria. Therefore, disruption of iron homeostasis can be an alternative strategy to cope with S. maltophilia infection. The intricate regulatory networks involved in iron hemostasis have been reported in various pathogens; however, little is known about S. maltophilia. Herein, a novel sbiTRS operon, a member of Fur regulon, was characterized. SbiT, an inner membrane protein, negatively modulated the SbiSR two-component regulatory system by intramembrane protein-protein interaction with SbiS. In response to iron-depleted stress, SbiSR was activated via the regulation of Fur and SbiT. Activated SbiSR upregulated smeDEF and sbiAB, which contributed to stenobactin-mediated ferric iron utilization. A novel fur-sbiT-sbiSR-smeDEF/sbiAB regulatory circuit in S. maltophilia was revealed.
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Affiliation(s)
- Cheng-Mu Wu
- Department of Biotechnology and Laboratory Science in Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Li-Hua Li
- Department of Pathology and Laboratory Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
- School of Medical Laboratory Science and Biotechnology, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | - Yen-Ling Lin
- Department of Biotechnology and Laboratory Science in Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Chao-Jung Wu
- School of Medical Laboratory Science and Biotechnology, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | - Yi-Tsung Lin
- Division of Infectious Diseases, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
- Department of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Tsuey-Ching Yang
- Department of Biotechnology and Laboratory Science in Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
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Keppel M, Piepenbreier H, Gätgens C, Fritz G, Frunzke J. Toxic but tasty - temporal dynamics and network architecture of heme-responsive two-component signaling in Corynebacterium glutamicum. Mol Microbiol 2019; 111:1367-1381. [PMID: 30767351 PMCID: PMC6850329 DOI: 10.1111/mmi.14226] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/11/2019] [Indexed: 01/24/2023]
Abstract
Heme is an essential cofactor and alternative iron source for almost all bacterial species but may cause severe toxicity upon elevated levels and consequently, regulatory mechanisms coordinating heme homeostasis represent an important fitness trait. A remarkable scenario is found in several corynebacterial species, e.g. Corynebacterium glutamicum and Corynebacterium diphtheriae, which dedicate two paralogous, heme-responsive two-component systems, HrrSA and ChrSA, to cope with the Janus nature of heme. Here, we combined experimental reporter profiling with a quantitative mathematical model to understand how this particular regulatory network architecture shapes the dynamic response to heme. Our data revealed an instantaneous activation of the detoxification response (hrtBA) upon stimulus perception and we found that kinase activity of both kinases contribute to this fast onset. Furthermore, instant deactivation of the PhrtBA promoter is achieved by a strong ChrS phosphatase activity upon stimulus decline. While the activation of detoxification response is uncoupled from further factors, heme utilization is additionally governed by the global iron regulator DtxR integrating information on iron availability into the regulatory network. Altogether, our data provide comprehensive insights how TCS cross-regulation and network hierarchy shape the temporal dynamics of detoxification (hrtBA) and utilization (hmuO) as part of a global homeostatic response to heme.
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Affiliation(s)
- Marc Keppel
- Institute of Bio- und Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich, Jülich, 52425, Germany
| | - Hannah Piepenbreier
- LOEWE-Zentrum für Synthetische Mikrobiologie, Philipps-Universität Marburg, Marburg, 35032, Germany
| | - Cornelia Gätgens
- Institute of Bio- und Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich, Jülich, 52425, Germany
| | - Georg Fritz
- LOEWE-Zentrum für Synthetische Mikrobiologie, Philipps-Universität Marburg, Marburg, 35032, Germany
| | - Julia Frunzke
- Institute of Bio- und Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich, Jülich, 52425, Germany
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Li C, Lillehoj HS, Gadde UD, Ritter D, Oh S. Characterization ofClostridium perfringensStrains Isolated from Healthy and Necrotic Enteritis-Afflicted Broiler Chickens. Avian Dis 2017; 61:178-185. [DOI: 10.1637/11507-093016-reg.1] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Charles Li
- Animal Biosciences and Biotechnology Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service–U.S. Department of Agriculture, 10300 Baltimore Avenue, Beltsville, MD 20705
| | - Hyun S. Lillehoj
- Animal Biosciences and Biotechnology Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service–U.S. Department of Agriculture, 10300 Baltimore Avenue, Beltsville, MD 20705
| | - Ujvala Deepthi Gadde
- Animal Biosciences and Biotechnology Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service–U.S. Department of Agriculture, 10300 Baltimore Avenue, Beltsville, MD 20705
| | - Don Ritter
- Mountaire Farms, 29005 John J. Williams Highway, Millsboro, DE 19966
| | - SungTaek Oh
- Animal Biosciences and Biotechnology Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service–U.S. Department of Agriculture, 10300 Baltimore Avenue, Beltsville, MD 20705
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Brewitz HH, Hagelueken G, Imhof D. Structural and functional diversity of transient heme binding to bacterial proteins. Biochim Biophys Acta Gen Subj 2017; 1861:683-697. [DOI: 10.1016/j.bbagen.2016.12.021] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 12/15/2016] [Accepted: 12/20/2016] [Indexed: 11/27/2022]
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6
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Choo JM, Cheung JK, Wisniewski JA, Steer DL, Bulach DM, Hiscox TJ, Chakravorty A, Smith AI, Gell DA, Rood JI, Awad MM. The NEAT Domain-Containing Proteins of Clostridium perfringens Bind Heme. PLoS One 2016; 11:e0162981. [PMID: 27637108 PMCID: PMC5026354 DOI: 10.1371/journal.pone.0162981] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 08/31/2016] [Indexed: 12/27/2022] Open
Abstract
The ability of a pathogenic bacterium to scavenge iron from its host is important for its growth and survival during an infection. Our studies on C. perfringens gas gangrene strain JIR325, a derivative of strain 13, showed that it is capable of utilizing both human hemoglobin and ferric chloride, but not human holo-transferrin, as an iron source for in vitro growth. Analysis of the C. perfringens strain 13 genome sequence identified a putative heme acquisition system encoded by an iron-regulated surface gene region that we have named the Cht (Clostridium perfringensheme transport) locus. This locus comprises eight genes that are co-transcribed and includes genes that encode NEAT domain-containing proteins (ChtD and ChtE) and a putative sortase (Srt). The ChtD, ChtE and Srt proteins were shown to be expressed in JIR325 cells grown under iron-limited conditions and were localized to the cell envelope. Moreover, the NEAT proteins, ChtD and ChtE, were found to bind heme. Both chtDE and srt mutants were constructed, but these mutants were not defective in hemoglobin or ferric chloride utilization. They were, however, attenuated for virulence when tested in a mouse myonecrosis model, although the virulence phenotype could not be restored via complementation and, as is common with such systems, secondary mutations were identified in these strains. In summary, this study provides evidence for the functional redundancies that occur in the heme transport pathways of this life threatening pathogen.
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Affiliation(s)
- Jocelyn M. Choo
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, VIC 3800, Australia
| | - Jackie K. Cheung
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, VIC 3800, Australia
| | - Jessica A. Wisniewski
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, VIC 3800, Australia
| | - David L. Steer
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Dieter M. Bulach
- Victorian Bioinformatics Consortium, Monash University, Clayton, Victoria, Australia
| | - Thomas J. Hiscox
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, VIC 3800, Australia
| | - Anjana Chakravorty
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, VIC 3800, Australia
| | - A. Ian Smith
- Victorian Bioinformatics Consortium, Monash University, Clayton, Victoria, Australia
| | - David A. Gell
- School of Medicine, University of Tasmania, Hobart, Tasmania 7000, Australia
| | - Julian I. Rood
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, VIC 3800, Australia
| | - Milena M. Awad
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, VIC 3800, Australia
- * E-mail:
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Sachla AJ, Ouattara M, Romero E, Agniswamy J, Weber IT, Gadda G, Eichenbaum Z. In vitro heme biotransformation by the HupZ enzyme from Group A streptococcus. Biometals 2016; 29:593-609. [PMID: 27154580 DOI: 10.1007/s10534-016-9937-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Accepted: 05/01/2016] [Indexed: 01/14/2023]
Abstract
In Group A streptococcus (GAS), the metallorepressor MtsR regulates iron homeostasis. Here we describe a new MtsR-repressed gene, which we named hupZ (heme utilization protein). A recombinant HupZ protein was purified bound to heme from Escherichia coli grown in the presence of 5-aminolevulinic acid and iron. HupZ specifically binds heme with stoichiometry of 1:1. The addition of NADPH to heme-bound HupZ (in the presence of cytochrome P450 reductase, NADPH-regeneration system and catalase) triggered progressive decrease of the HupZ Soret band and the appearance of an absorption peak at 660 nm that was resistance to hydrolytic conditions. No spectral changes were observed when ferredoxin and ferredoxin reductase were used as redox partners. Differential spectroscopy with myoglobin or with the ferrous chelator, ferrozine, confirmed that carbon monoxide and free iron are produced during the reaction. ApoHupZ was crystallized as a homodimer with a split β-barrel conformation in each monomer comprising six β strands and three α helices. This structure resembles the split β-barrel domain shared by the members of a recently described family of heme degrading enzymes. However, HupZ is smaller and lacks key residues found in the proteins of the latter group. Phylogenetic analysis places HupZ on a clade separated from those for previously described heme oxygenases. In summary, we have identified a new GAS enzyme-containing split β-barrel and capable of heme biotransformation in vitro; to the best of our knowledge, this is the first enzyme among Streptococcus species with such activity.
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Affiliation(s)
- Ankita J Sachla
- Department of Biology, College of Arts and Sciences, Georgia State University, P.O. Box 4010, Atlanta, GA, 30302-4010, USA
| | - Mahamoudou Ouattara
- Department of Biology, College of Arts and Sciences, Georgia State University, P.O. Box 4010, Atlanta, GA, 30302-4010, USA
| | - Elvira Romero
- Department of Chemistry, College of Arts and Sciences, Georgia State University, Atlanta, GA, 30302-3965, USA
| | - Johnson Agniswamy
- Department of Biology, College of Arts and Sciences, Georgia State University, P.O. Box 4010, Atlanta, GA, 30302-4010, USA
| | - Irene T Weber
- Department of Biology, College of Arts and Sciences, Georgia State University, P.O. Box 4010, Atlanta, GA, 30302-4010, USA.,Department of Chemistry, College of Arts and Sciences, Georgia State University, Atlanta, GA, 30302-3965, USA.,Center for Biotechnology and Drug Design, Georgia State University, Atlanta, GA, 30303, USA
| | - Giovanni Gadda
- Department of Biology, College of Arts and Sciences, Georgia State University, P.O. Box 4010, Atlanta, GA, 30302-4010, USA.,Department of Chemistry, College of Arts and Sciences, Georgia State University, Atlanta, GA, 30302-3965, USA.,Center for Biotechnology and Drug Design, Georgia State University, Atlanta, GA, 30303, USA.,Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA, 30303, USA
| | - Zehava Eichenbaum
- Department of Biology, College of Arts and Sciences, Georgia State University, P.O. Box 4010, Atlanta, GA, 30302-4010, USA.
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Muraki N, Kitatsuji C, Aono S. A new biological function of heme as a signaling molecule. J PORPHYR PHTHALOCYA 2015. [DOI: 10.1142/s1088424614501090] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
This mini-review presents a recent development of a new function of heme as a signaling molecule especially in the regulation of gene expression. Heme is biosynthesized as a prosthetic group for heme proteins, which play crucial roles for respiration, photosynthesis, and many other metabolic reactions. In some bacteria, exogenous heme molecules are used as a heme or an iron sources to be uptaken into cytoplasm. As free heme molecules are cytotoxic, the intracellular concentrations of biosynthesized or uptaken heme should be strictly controlled. In this mini-review, we summarize the biochemical and biophysical properties of the transcriptional regulators and heme-sensor proteins responsible for these regulatory systems to maintain heme homeostasis.
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Affiliation(s)
- Norifumi Muraki
- Okazaki Institute for Integrative Bioscience & Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan
| | - Chihiro Kitatsuji
- Okazaki Institute for Integrative Bioscience & Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan
| | - Shigetoshi Aono
- Okazaki Institute for Integrative Bioscience & Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan
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9
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Apo-bacteriophytochromes modulate bacterial photosynthesis in response to low light. Proc Natl Acad Sci U S A 2013; 111:E237-44. [PMID: 24379368 DOI: 10.1073/pnas.1322410111] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bacteriophytochromes (BphPs) are light-sensing regulatory proteins encoded by photosynthetic and nonphotosynthetic bacteria. This protein class has been characterized structurally, but its biological activities remain relatively unexplored. Two BphPs in the anoxygenic photosynthetic bacterium Rhodopseudomonas palustris, designated regulatory proteins RpBphP2 and RpBphP3, are configured as light-regulated histidine kinases, which initiate a signal transduction system that controls expression of genes for the low light harvesting 4 (LH4) antenna complex. In vitro, RpBphP2 and RpBphP3 respond to light quality by reversible photoconversion, a property that requires the light-absorbing chromophore biliverdin. In vivo, RpBphP2 and RpBphP3 are both required for the expression of the LH4 antenna complex under anaerobic conditions, but biliverdin requires oxygen for its synthesis by heme oxygenase. On further investigation, we found that the apo-bacteriophytochrome forms of RpBphP2 and RpBphP3 are necessary and sufficient to control LH4 expression in response to light intensity in conjunction with other signal transduction proteins. One possibility is that the system senses a reduced quinone pool generated when light energy is absorbed by bacteriochlorophyll. The biliverdin-bound forms of the BphPs have the additional property of being able to fine-tune LH4 expression in response to light quality. These observations support the concept that some bacteriophytochromes can function with or without a chromophore and may be involved in regulating physiological processes not directly related to light sensing.
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Connan C, Denève C, Mazuet C, Popoff MR. Regulation of toxin synthesis in Clostridium botulinum and Clostridium tetani. Toxicon 2013; 75:90-100. [DOI: 10.1016/j.toxicon.2013.06.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Revised: 05/25/2013] [Accepted: 06/04/2013] [Indexed: 01/11/2023]
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Gruss A, Borezée-Durant E, Lechardeur D. Environmental heme utilization by heme-auxotrophic bacteria. Adv Microb Physiol 2013; 61:69-124. [PMID: 23046952 DOI: 10.1016/b978-0-12-394423-8.00003-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Heme, an iron-containing porphyrin, is the prosthetic group for numerous key cellular enzymatic and regulatory processes. Many bacteria encode the biosynthetic enzymes needed for autonomous heme production. Remarkably, however, numerous other bacteria lack a complete heme biosynthesis pathway, yet encode heme-requiring functions. For such heme-auxotrophic bacteria (HAB), heme or porphyrins must be captured from the environment. Functional studies, aided by genomic analyses, provide insight into the HAB lifestyle, how they acquire and manage heme, and the uses of heme that make it worthwhile, and sometimes necessary, to capture this bioactive molecule.
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Affiliation(s)
- Alexandra Gruss
- INRA, UMR1319 Micalis and AgroParisTech, UMR Micalis, Jouy-en-Josas, France
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12
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Tavares AFN, Nobre LS, Saraiva LM. A role for reactive oxygen species in the antibacterial properties of carbon monoxide-releasing molecules. FEMS Microbiol Lett 2012; 336:1-10. [PMID: 22774863 DOI: 10.1111/j.1574-6968.2012.02633.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Revised: 07/02/2012] [Accepted: 07/03/2012] [Indexed: 12/24/2022] Open
Abstract
Carbon monoxide-releasing molecules (CO-RMs) are, in general, transition metal carbonyl complexes that liberate controlled amounts of CO. In animal models, CO-RMs have been shown to reduce myocardial ischaemia, inflammation and vascular dysfunction, and to provide a protective effect in organ transplantation. Moreover, CO-RMs are bactericides that kill both Gram-positive and Gram-negative bacteria such as Staphylococcus aureus and Pseudomonas aeruginosa. Herein are reviewed the microbial genetic and biochemical responses associated with CO-RM-mediated cell death. Particular emphasis is given to the data revealing that CO-RMs induce the generation of reactive oxygen species (ROS), which contribute to the antibacterial activity of these compounds.
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Affiliation(s)
- Ana Filipa N Tavares
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
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13
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Connan C, Brueggemann H, Mazuet C, Raffestin S, Cayet N, Popoff MR. Two-component systems are involved in the regulation of botulinum neurotoxin synthesis in Clostridium botulinum type A strain Hall. PLoS One 2012; 7:e41848. [PMID: 22848632 PMCID: PMC3406050 DOI: 10.1371/journal.pone.0041848] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Accepted: 06/29/2012] [Indexed: 11/30/2022] Open
Abstract
Clostridium botulinum synthesizes a potent neurotoxin (BoNT) which associates with non-toxic proteins (ANTPs) to form complexes of various sizes. The bont and antp genes are clustered in two operons. In C. botulinum type A, bont/A and antp genes are expressed during the end of the exponential growth phase and the beginning of the stationary phase under the control of an alternative sigma factor encoded by botR/A, which is located between the two operons. In the genome of C. botulinum type A strain Hall, 30 gene pairs predicted to encode two-component systems (TCSs) and 9 orphan regulatory genes have been identified. Therefore, 34 Hall isogenic antisense strains on predicted regulatory genes (29 TCSs and 5 orphan regulatory genes) have been obtained by a mRNA antisense procedure. Two TCS isogenic antisense strains showed more rapid growth kinetics and reduced BoNT/A production than the control strain, as well as increased bacterial lysis and impairment of the bacterial cell wall structure. Three other TCS isogenic antisense strains induced a low level of BoNT/A and ANTP production. Interestingly, reduced expression of bont/A and antp genes was shown to be independent of botR/A. These results indicate that BoNT/A synthesis is under the control of a complex network of regulation including directly at least three TCSs.
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Affiliation(s)
- Chloé Connan
- Institut Pasteur, Bactéries anaérobies et Toxines, Paris, France
| | | | | | | | - Nadège Cayet
- Institut Pasteur, Plateforme de Microscopie Ultrastructurale, Paris, France
| | - Michel R. Popoff
- Institut Pasteur, Bactéries anaérobies et Toxines, Paris, France
- * E-mail:
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Overcoming the heme paradox: heme toxicity and tolerance in bacterial pathogens. Infect Immun 2010; 78:4977-89. [PMID: 20679437 DOI: 10.1128/iai.00613-10] [Citation(s) in RCA: 208] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Virtually all bacterial pathogens require iron to infect vertebrates. The most abundant source of iron within vertebrates is in the form of heme as a cofactor of hemoproteins. Many bacterial pathogens have elegant systems dedicated to the acquisition of heme from host hemoproteins. Once internalized, heme is either degraded to release free iron or used intact as a cofactor in catalases, cytochromes, and other bacterial hemoproteins. Paradoxically, the high redox potential of heme makes it a liability, as heme is toxic at high concentrations. Although a variety of mechanisms have been proposed to explain heme toxicity, the mechanisms by which heme kills bacteria are not well understood. Nonetheless, bacteria employ various strategies to protect against and eliminate heme toxicity. Factors involved in heme acquisition and detoxification have been found to contribute to virulence, underscoring the physiological relevance of heme stress during pathogenesis. Herein we describe the current understanding of the mechanisms of heme toxicity and how bacterial pathogens overcome the heme paradox during infection.
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