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Pires PM, Santos D, Calisto F, Pereira M. The monotopic quinone reductases from Staphylococcus aureus. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2024; 1865:149488. [PMID: 38950690 DOI: 10.1016/j.bbabio.2024.149488] [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: 04/30/2024] [Accepted: 06/27/2024] [Indexed: 07/03/2024]
Abstract
Staphylococcus aureus, a Gram-positive bacterium, is an opportunistic pathogen and one of the most frequent causes for community acquired and nosocomial infections that has become a major public health threat due to the increased incidence of its drug resistance. Although being a prominent pathogen, its energetic metabolism is still underexplored, and its respiratory enzymes have been escaping attention. S. aureus can adapt to different environmental conditions by performing both aerobic and anaerobic respirations, which is particularly important as it frequently colonizes niches with different oxygen concentrations. This adaptability is derived from the composition of its respiratory chain, specifically from the presence of terminal electron acceptor reductases. The plasticity of S. aureus energy metabolism is enlarged by the ten quinone reductases encoded in its genome, eight of them being monotopic proteins. The role of these proteins is critical as they connect the different catabolic pathways to the respiratory chain. In this work, we identify, describe, and revise the monotopic quinone reductases present in S. aureus, providing an integrated view of its respiratory chain.
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Affiliation(s)
- Patrícia M Pires
- University of Lisbon, Faculty of Sciences, Department of Chemistry and Biochemistry and BioISI - Biosystems & Integrative Sciences Institute, Campo Grande, C8, 1749-016 Lisboa, Portugal
| | - David Santos
- University of Lisbon, Faculty of Sciences, Department of Chemistry and Biochemistry and BioISI - Biosystems & Integrative Sciences Institute, Campo Grande, C8, 1749-016 Lisboa, Portugal
| | - Filipa Calisto
- University of Lisbon, Faculty of Sciences, Department of Chemistry and Biochemistry and BioISI - Biosystems & Integrative Sciences Institute, Campo Grande, C8, 1749-016 Lisboa, Portugal
| | - Manuela Pereira
- University of Lisbon, Faculty of Sciences, Department of Chemistry and Biochemistry and BioISI - Biosystems & Integrative Sciences Institute, Campo Grande, C8, 1749-016 Lisboa, Portugal.
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2
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Darwitz BP, Genito CJ, Thurlow LR. Triple threat: how diabetes results in worsened bacterial infections. Infect Immun 2024; 92:e0050923. [PMID: 38526063 PMCID: PMC11385445 DOI: 10.1128/iai.00509-23] [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] [Indexed: 03/26/2024] Open
Abstract
Diabetes mellitus, characterized by impaired insulin signaling, is associated with increased incidence and severity of infections. Various diabetes-related complications contribute to exacerbated bacterial infections, including hyperglycemia, innate immune cell dysfunction, and infection with antibiotic-resistant bacterial strains. One defining symptom of diabetes is hyperglycemia, resulting in elevated blood and tissue glucose concentrations. Glucose is the preferred carbon source of several bacterial pathogens, and hyperglycemia escalates bacterial growth and virulence. Hyperglycemia promotes specific mechanisms of bacterial virulence known to contribute to infection chronicity, including tissue adherence and biofilm formation. Foot infections are a significant source of morbidity in individuals with diabetes and consist of biofilm-associated polymicrobial communities. Bacteria perform complex interspecies behaviors conducive to their growth and virulence within biofilms, including metabolic cross-feeding and altered phenotypes more tolerant to antibiotic therapeutics. Moreover, the metabolic dysfunction caused by diabetes compromises immune cell function, resulting in immune suppression. Impaired insulin signaling induces aberrations in phagocytic cells, which are crucial mediators for controlling and resolving bacterial infections. These aberrancies encompass altered cytokine profiles, the migratory and chemotactic mechanisms of neutrophils, and the metabolic reprogramming required for the oxidative burst and subsequent generation of bactericidal free radicals. Furthermore, the immune suppression caused by diabetes and the polymicrobial nature of the diabetic infection microenvironment may promote the emergence of novel strains of multidrug-resistant bacterial pathogens. This review focuses on the "triple threat" linked to worsened bacterial infections in individuals with diabetes: (i) altered nutritional availability in diabetic tissues, (ii) diabetes-associated immune suppression, and (iii) antibiotic treatment failure.
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Affiliation(s)
- Benjamin P Darwitz
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina, USA
| | - Christopher J Genito
- Division of Oral and Craniofacial Health Sciences, University of North Carolina at Chapel Hill Adams School of Dentistry, Chapel Hill, North Carolina, USA
| | - Lance R Thurlow
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina, USA
- Division of Oral and Craniofacial Health Sciences, University of North Carolina at Chapel Hill Adams School of Dentistry, Chapel Hill, North Carolina, USA
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3
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Lehman MK. mSphere of Influence: Metabolic redundancies enhance pathogenesis. mSphere 2024; 9:e0023924. [PMID: 38958458 PMCID: PMC11288011 DOI: 10.1128/msphere.00239-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/04/2024] Open
Abstract
McKenzie Lehman works in the field of bacterial pathogenesis and metabolism. In this mSphere of Influence article, she reflects on how three papers entitled "Glycolytic dependency of high-level nitric oxide resistance and virulence in Staphylococcus aureus" by N. P. Vitko, N. A. Spahich, and A. R. Richardson (mBio 6:e00045-15, 2015, https://doi.org/10.1128/mbio.00045-15), "The Staphylococcus aureus cystine transporters TcyABC and TcyP facilitate nutrient sulfur acquisition during infection" by J. M. Lensmire, J. P. Dodson, B. Y. Hsueh, M. R. Wischer, et al. (Infect Immun 88:e00690-19, 2020, https://doi.org/10.1128/iai.00690-19), and "The second messenger c-di-AMP inhibits the osmolyte uptake system OpuC in Staphylococcus aureus" by C. F. Schuster, L. E. Bellows, T. Tosi, I. Campeotto, et al. (Sci Signal 16:ra81, 2016, https://doi.org/10.1126/scisignal.aaf7279) impacted her work on bacterial metabolism and pathogenesis.
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Affiliation(s)
- McKenzie K. Lehman
- Department of Pathology, Microbiology and Immunology, University of Nebraska Medical Center, Omaha, Nebraska, USA
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4
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Henry SA, Webster CM, Shaw LN, Torres NJ, Jobson ME, Totzke BC, Jackson JK, McGreig JE, Wass MN, Robinson GK, Shepherd M. Steroid Drugs Inhibit Bacterial Respiratory Oxidases and Are Lethal Toward Methicillin-Resistant Staphylococcus aureus. J Infect Dis 2024; 230:e149-e158. [PMID: 39052707 PMCID: PMC11272085 DOI: 10.1093/infdis/jiad540] [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: 07/21/2023] [Accepted: 11/28/2023] [Indexed: 02/16/2024] Open
Abstract
BACKGROUND Cytochrome bd complexes are respiratory oxidases found exclusively in prokaryotes that are important during infection for numerous bacterial pathogens. METHODS In silico docking was employed to screen approved drugs for their ability to bind to the quinol site of Escherichia coli cytochrome bd-I. Respiratory inhibition was assessed with oxygen electrodes using membranes isolated from E. coli and methicillin-resistant Staphylococcus aureus strains expressing single respiratory oxidases (ie, cytochromes bd, bo', or aa3). Growth/viability assays were used to measure bacteriostatic and bactericidal effects. RESULTS The steroid drugs ethinylestradiol and quinestrol inhibited E. coli bd-I activity with median inhibitory concentration (IC50) values of 47 ± 28.9 µg/mL (158 ± 97.2 µM) and 0.2 ± 0.04 µg/mL (0.5 ± 0.1 µM), respectively. Quinestrol inhibited growth of an E. coli "bd-I only" strain with an IC50 of 0.06 ± 0.02 µg/mL (0.2 ± 0.07 µM). Growth of an S. aureus "bd only" strain was inhibited by quinestrol with an IC50 of 2.2 ± 0.43 µg/mL (6.0 ± 1.2 µM). Quinestrol exhibited potent bactericidal effects against S. aureus but not E. coli. CONCLUSIONS Quinestrol inhibits cytochrome bd in E. coli and S. aureus membranes and inhibits the growth of both species, yet is only bactericidal toward S. aureus.
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Affiliation(s)
- Samantha A Henry
- School of Biosciences, University of Kent, Canterbury, United Kingdom
| | - Calum M Webster
- School of Biosciences, University of Kent, Canterbury, United Kingdom
| | - Lindsey N Shaw
- Department of Molecular Biosciences, University of South Florida, Tampa
| | | | | | - Brendan C Totzke
- Department of Molecular Biosciences, University of South Florida, Tampa
| | - Jessica K Jackson
- Department of Molecular Biosciences, University of South Florida, Tampa
| | - Jake E McGreig
- School of Biosciences, University of Kent, Canterbury, United Kingdom
| | - Mark N Wass
- School of Biosciences, University of Kent, Canterbury, United Kingdom
| | - Gary K Robinson
- School of Biosciences, University of Kent, Canterbury, United Kingdom
| | - Mark Shepherd
- School of Biosciences, University of Kent, Canterbury, United Kingdom
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5
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Suzuki Y, Kawada-Matsuo M, Le MNT, Eng S, Hisatsune J, Sugai M, Sakaguchi T, Komatsuzawa H. The two-component regulatory systems GraRS and SrrAB mediate Staphylococcus aureus susceptibility to Pep5 produced by clinical isolate of Staphylococcus epidermidis. Appl Environ Microbiol 2024; 90:e0030024. [PMID: 38832774 PMCID: PMC11267926 DOI: 10.1128/aem.00300-24] [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: 02/26/2024] [Accepted: 05/08/2024] [Indexed: 06/05/2024] Open
Abstract
Staphylococcus aureus is a common bacterium on the skin and in the nose that sometimes causes severe illness. Bacteriocins, antimicrobial peptides, or proteins produced by bacteria are candidates for the treatment of S. aureus infection. In this study, we found that a clinical Staphylococcus epidermidis strain, KSE112, produced the lantibiotic Pep5, which showed anti-S. aureus activity. The complete nucleotide sequence of the Pep5-encoding plasmid was determined. Several S. aureus two-component regulatory systems (TCSs) are known to be involved in bacteriocin susceptibility. Therefore, susceptibility tests were performed using TCS-inactivated S. aureus mutants to determine which TCS is responsible for Pep5 susceptibility; the ΔgraRS mutant exhibited increased susceptibility to Pep5, while the ΔsrrAB mutant exhibited decreased susceptibility. GraRS is known to regulate dltABCD and mprF in concert with vraFG, and Pep5 susceptibility was significantly increased in the ΔdltABCD, ΔmprF, and ΔvraFG mutants. Regarding the ΔsrrAB mutant, cross-resistance to aminoglycosides was observed. As aminoglycoside activity is known to be affected by aerobic respiration, we focused on qoxABCD and cydAB, which are quinol oxidase genes that are necessary for aerobic respiration and have downregulated the expression in the ΔsrrAB mutant. We constructed ΔqoxABCD and ΔcydAB mutants and found that qoxABCD inactivation decreased susceptibility to Pep5 and aminoglycosides. These results indicate that reduced aerobic respiration due to the reduced qoxABCD expression in the ΔsrrAB mutant decreased Pep5 activity.IMPORTANCEThe emergence of drug-resistant bacteria, including MRSA, is a severe health problem worldwide. Thus, the development of novel antimicrobial agents, including bacteriocins, is needed. In this report, we found a Pep5-producing strain with anti-S. aureus activity. We determined the complete sequence of the Pep5-encoding plasmid for the first time. However, in S. aureus, GraRS and its effectors conferred decreased susceptibility to Pep5. We also revealed that another TCS, SrrAB, affects susceptibility Pep5 and other lantibiotics by controlling aerobic respiration. In our study, we investigated the efficacy of Pep5 against S. aureus and other Gram-positive bacteria and revealed that respiratory constancy regulated by TCS is required for the antimicrobial activity of nisin, nukacin, and Pep5. These findings provide important information for the clinical application of bacteriocins and suggest that they have different properties among similar pore-forming lantibiotics.
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Affiliation(s)
- Yujin Suzuki
- Department of Bacteriology, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan
- Department of Virology, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan
- Antimicrobial Resistance Research Center, National Institute of Infectious Diseases, Higashi Murayama, Japan
| | - Miki Kawada-Matsuo
- Department of Bacteriology, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan
- Project Research Centre for Nosocomial Infectious Diseases, Hiroshima University, Hiroshima, Japan
| | - Mi Nguyen-Tra Le
- Department of Bacteriology, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan
- Project Research Centre for Nosocomial Infectious Diseases, Hiroshima University, Hiroshima, Japan
| | - Sopongselamuny Eng
- Department of Bacteriology, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan
| | - Junzo Hisatsune
- Antimicrobial Resistance Research Center, National Institute of Infectious Diseases, Higashi Murayama, Japan
- Project Research Centre for Nosocomial Infectious Diseases, Hiroshima University, Hiroshima, Japan
| | - Motoyuki Sugai
- Antimicrobial Resistance Research Center, National Institute of Infectious Diseases, Higashi Murayama, Japan
- Project Research Centre for Nosocomial Infectious Diseases, Hiroshima University, Hiroshima, Japan
| | - Takemasa Sakaguchi
- Department of Virology, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan
| | - Hitoshi Komatsuzawa
- Department of Bacteriology, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan
- Project Research Centre for Nosocomial Infectious Diseases, Hiroshima University, Hiroshima, Japan
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6
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McKay LS, Spandrio AR, Johnson RM, Sobran MA, Marlatt SA, Mote KB, Dedloff MR, Nash ZM, Julio SM, Cotter PA. Cytochrome oxidase requirements in Bordetella reveal insights into evolution towards life in the mammalian respiratory tract. PLoS Pathog 2024; 20:e1012084. [PMID: 38976749 PMCID: PMC11257404 DOI: 10.1371/journal.ppat.1012084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 07/18/2024] [Accepted: 06/17/2024] [Indexed: 07/10/2024] Open
Abstract
Little is known about oxygen utilization during infection by bacterial respiratory pathogens. The classical Bordetella species, including B. pertussis, the causal agent of human whooping cough, and B. bronchiseptica, which infects nearly all mammals, are obligate aerobes that use only oxygen as the terminal electron acceptor for electron transport-coupled oxidative phosphorylation. B. bronchiseptica, which occupies many niches, has eight distinct cytochrome oxidase-encoding loci, while B. pertussis, which evolved from a B. bronchiseptica-like ancestor but now survives exclusively in and between human respiratory tracts, has only three functional cytochrome oxidase-encoding loci: cydAB1, ctaCDFGE1, and cyoABCD1. To test the hypothesis that the three cytochrome oxidases encoded within the B. pertussis genome represent the minimum number and class of cytochrome oxidase required for respiratory infection, we compared B. bronchiseptica strains lacking one or more of the eight possible cytochrome oxidases in vitro and in vivo. No individual cytochrome oxidase was required for growth in ambient air, and all three of the cytochrome oxidases conserved in B. pertussis were sufficient for growth in ambient air and low oxygen. Using a high-dose, large-volume persistence model and a low-dose, small-volume establishment of infection model, we found that B. bronchiseptica producing only the three B. pertussis-conserved cytochrome oxidases was indistinguishable from the wild-type strain for infection. We also determined that CyoABCD1 is sufficient to cause the same level of bacterial burden in mice as the wild-type strain and is thus the primary cytochrome oxidase required for murine infection, and that CydAB1 and CtaCDFGE1 fulfill auxiliary roles or are important for aspects of infection we have not assessed, such as transmission. Our results shed light on the environment at the surface of the ciliated epithelium, respiration requirements for bacteria that colonize the respiratory tract, and the evolution of virulence in bacterial pathogens.
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Affiliation(s)
- Liliana S. McKay
- Department of Microbiology and Immunology, School of Medicine, University of North Carolina—Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Alexa R. Spandrio
- Department of Microbiology and Immunology, School of Medicine, University of North Carolina—Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Richard M. Johnson
- Department of Microbiology and Immunology, School of Medicine, University of North Carolina—Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - M. Ashley Sobran
- Department of Microbiology and Immunology, School of Medicine, University of North Carolina—Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Sara A. Marlatt
- Department of Microbiology and Immunology, School of Medicine, University of North Carolina—Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Katlyn B. Mote
- Department of Microbiology and Immunology, School of Medicine, University of North Carolina—Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Margaret R. Dedloff
- Department of Microbiology and Immunology, School of Medicine, University of North Carolina—Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Zachary M. Nash
- Department of Microbiology and Immunology, School of Medicine, University of North Carolina—Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Steven M. Julio
- Department of Biology, Westmont College, Santa Barbara, California, United States of America
| | - Peggy A. Cotter
- Department of Microbiology and Immunology, School of Medicine, University of North Carolina—Chapel Hill, Chapel Hill, North Carolina, United States of America
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7
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Korshoj LE, Kielian T. Bacterial single-cell RNA sequencing captures biofilm transcriptional heterogeneity and differential responses to immune pressure. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.28.601229. [PMID: 38979200 PMCID: PMC11230364 DOI: 10.1101/2024.06.28.601229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
Biofilm formation is an important mechanism of survival and persistence for many bacterial pathogens. These multicellular communities contain subpopulations of cells that display vast metabolic and transcriptional diversity along with high recalcitrance to antibiotics and host immune defenses. Investigating the complex heterogeneity within biofilm has been hindered by the lack of a sensitive and high-throughput method to assess stochastic transcriptional activity and regulation between bacterial subpopulations, which requires single-cell resolution. We have developed an optimized bacterial single-cell RNA sequencing method, BaSSSh-seq, to study Staphylococcus aureus diversity during biofilm growth and transcriptional adaptations following immune cell exposure. We validated the ability of BaSSSh-seq to capture extensive transcriptional heterogeneity during biofilm compared to planktonic growth. Application of new computational tools revealed transcriptional regulatory networks across the heterogeneous biofilm subpopulations and identification of gene sets that were associated with a trajectory from planktonic to biofilm growth. BaSSSh-seq also detected alterations in biofilm metabolism, stress response, and virulence that were tailored to distinct immune cell populations. This work provides an innovative platform to explore biofilm dynamics at single-cell resolution, unlocking the potential for identifying biofilm adaptations to environmental signals and immune pressure.
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8
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Campbell K, Kowalski CH, Kohler KM, Barber MF. Evolution of polyamine resistance in Staphylococcus aureus through modulation of potassium transport. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.15.599172. [PMID: 38915543 PMCID: PMC11195161 DOI: 10.1101/2024.06.15.599172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
Microbes must adapt to diverse biotic and abiotic factors encountered in host environments. Polyamines are an abundant class of aliphatic molecules that play essential roles in fundamental cellular processes across the tree of life. Surprisingly, the bacterial pathogen Staphylococcus aureus is highly sensitive to polyamines encountered during infection, and acquisition of a polyamine resistance locus has been implicated in spread of the prominent USA300 methicillin-resistant S. aureus lineage. At present, alternative pathways of polyamine resistance in staphylococci are largely unknown. Here we applied experimental evolution to identify novel mechanisms and consequences of S. aureus adaption when exposed to increasing concentrations of the polyamine spermine. Evolved populations of S. aureus exhibited striking evidence of parallel adaptation, accumulating independent mutations in the potassium transporter genes ktrA and ktrD. Mutations in either ktrA or ktrD are sufficient to confer polyamine resistance and function in an additive manner. Moreover, we find that ktr mutations provide increased resistance to multiple classes of unrelated cationic antibiotics, suggesting a common mechanism of resistance. Consistent with this hypothesis, ktr mutants exhibit alterations in cell surface charge indicative of reduced affinity and uptake of cationic molecules. Finally, we observe that laboratory-evolved ktr mutations are also present in diverse natural S. aureus isolates, suggesting these mutations may contribute to antimicrobial resistance during human infections. Collectively this study identifies a new role for potassium transport in S. aureus polyamine resistance with consequences for susceptibility to both host-derived and clinically-used antimicrobials.
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Affiliation(s)
- Killian Campbell
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR USA
- Department of Biology, University of Oregon, Eugene, OR USA
| | | | - Kristin M. Kohler
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR USA
| | - Matthew F. Barber
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR USA
- Department of Biology, University of Oregon, Eugene, OR USA
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9
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Kanesaka I, Yabuta J, Jitsukawa T, Fujisaki S, Morita M, Mikawa T, Kanayama Katsuse A, Takahashi H, Ohno A, Kobayashi I. Population Analysis of Daptomycin-non-Susceptible Methicillin-Resistant Staphylococcus aureus Reveals the Presence of Variants That Contribute to Daptomycin Resistance. Curr Microbiol 2024; 81:61. [PMID: 38206417 DOI: 10.1007/s00284-023-03579-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 11/29/2023] [Indexed: 01/12/2024]
Abstract
In this study, population analysis (PA) of methicillin-resistant Staphylococcus aureus (MRSA), before and after long-duration daptomycin (DAP) treatment, was used to detect subpopulations with different susceptibilities to DAP and to verify the changes in the number of resistant cells. Furthermore, we aimed to characterize the bacteriology of the variants present in the non-susceptible cell subpopulation. A DAP non-susceptible (NS) MRSA phenotype (D2) that emerged from a DAP- susceptible MRSA phenotype (D1) during treatment of an open wound, was used for testing. We performed bacteriological and genetic analyses of cryptic DAP-NS MRSA variants detected by PA to study the variants present in the resistant cell subpopulation. PA results suggest that MRSA adapted to survival in the presence of DAP are selected leading to reduced susceptibility. Within the cell population growing in media containing 2.0 mg/L of DAP, three variants with different pigment production and colony size were detected. Variant 3 was an orange colony due to enhanced production of staphyloxanthin. Our results revealed that the DAP minimum inhibitory concentration (MIC) value increased two-fold (4 mg/L) in variant 3, in which pigment production was most enhanced, compared to the parental strain D2. In conclusion, our results indicate that long-duration DAP treatment can lead to the emergence and increased proportion of DAP-NS subpopulations. Furthermore, slow-growing variants that can be detected only under antimicrobial selective pressure are present among DAP-NS cells, suggesting that these variants may also contribute to the development of DAP resistance.
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Affiliation(s)
- Izumo Kanesaka
- Department of Infection Control and Prevention, Faculty of Nursing, Toho University, 4-16-20, Omori-Nishi, Ota-Ku, Tokyo, 143-0015, Japan
- Department of Biomolecular Science, Faculty of Science, Toho University, 2-2-1, Miyama, Funabashi-Shi, Chiba, 274-8510, Japan
| | - Junya Yabuta
- Department of Biomolecular Science, Faculty of Science, Toho University, 2-2-1, Miyama, Funabashi-Shi, Chiba, 274-8510, Japan
| | - Tomotaka Jitsukawa
- Department of Biomolecular Science, Faculty of Science, Toho University, 2-2-1, Miyama, Funabashi-Shi, Chiba, 274-8510, Japan
| | - Shingo Fujisaki
- Department of Biomolecular Science, Faculty of Science, Toho University, 2-2-1, Miyama, Funabashi-Shi, Chiba, 274-8510, Japan
| | - Masahiro Morita
- Department of Infection Control and Prevention, Faculty of Nursing, Toho University, 4-16-20, Omori-Nishi, Ota-Ku, Tokyo, 143-0015, Japan
| | - Takashi Mikawa
- Department of Infection Control and Prevention, Faculty of Nursing, Toho University, 4-16-20, Omori-Nishi, Ota-Ku, Tokyo, 143-0015, Japan
| | - Akiko Kanayama Katsuse
- Department of Infection Control and Prevention, Faculty of Nursing, Toho University, 4-16-20, Omori-Nishi, Ota-Ku, Tokyo, 143-0015, Japan
| | - Hiroshi Takahashi
- Department of Infection Control and Prevention, Faculty of Nursing, Toho University, 4-16-20, Omori-Nishi, Ota-Ku, Tokyo, 143-0015, Japan
| | - Akira Ohno
- Department of Infection Control and Prevention, Faculty of Nursing, Toho University, 4-16-20, Omori-Nishi, Ota-Ku, Tokyo, 143-0015, Japan
| | - Intetsu Kobayashi
- Department of Infection Control and Prevention, Faculty of Nursing, Toho University, 4-16-20, Omori-Nishi, Ota-Ku, Tokyo, 143-0015, Japan.
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10
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Maire J, Philip GK, Livingston J, Judd LM, Blackall LL, van Oppen MJH. Functional potential and evolutionary response to long-term heat selection of bacterial associates of coral photosymbionts. mSystems 2023; 8:e0086023. [PMID: 37909753 PMCID: PMC10746172 DOI: 10.1128/msystems.00860-23] [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: 08/14/2023] [Accepted: 09/28/2023] [Indexed: 11/03/2023] Open
Abstract
IMPORTANCE Symbiotic microorganisms are crucial for the survival of corals and their resistance to coral bleaching in the face of climate change. However, the impact of microbe-microbe interactions on coral functioning is mostly unknown but could be essential factors for coral adaption to future climates. Here, we investigated interactions between cultured dinoflagellates of the Symbiodiniaceae family, essential photosymbionts of corals, and associated bacteria. By assessing the genomic potential of 49 bacteria, we found that they are likely beneficial for Symbiodiniaceae, through the production of B vitamins and antioxidants. Additionally, bacterial genes involved in host-symbiont interactions, such as secretion systems, accumulated mutations following long-term exposure to heat, suggesting symbiotic interactions may change under climate change. This highlights the importance of microbe-microbe interactions in coral functioning.
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Affiliation(s)
- Justin Maire
- School of BioSciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Gayle K. Philip
- Melbourne Bioinformatics, The University of Melbourne, Parkville, Victoria, Australia
| | - Jadzia Livingston
- School of BioSciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Louise M. Judd
- Doherty Applied Microbial Genomics, Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Parkville, Victoria, Australia
| | - Linda L. Blackall
- School of BioSciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Madeleine J. H. van Oppen
- School of BioSciences, The University of Melbourne, Parkville, Victoria, Australia
- Australian Institute of Marine Science, Townsville, Queensland, Australia
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11
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Choi SR, Narayanasamy P. In Vitro and In Vivo Antimicrobial Activity of an Oxidative Stress-Mediated Bicyclic Menaquinone Biosynthesis Inhibitor against MRSA. ACS Infect Dis 2023; 9:2016-2024. [PMID: 37655755 DOI: 10.1021/acsinfecdis.3c00319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
Abstract
Menaquinone (MK) is an essential component in the oxidative phosphorylation pathway of Gram-positive bacteria. Drugs targeting enzymes involved in MK biosynthesis can prevent electron transfer, which leads to ATP starvation and thereby death of microorganisms. Previously, we reported a series of MenA inhibitors and demonstrated their antimicrobial activity against Gram-positive bacteria, including Methicillin-resistant Staphylococcus aureus (MRSA) and mycobacteria. These inhibitors were developed by mimicking demethylmenaquinone, a product of MenA enzymatic reaction in MK biosynthesis. In this study, compound NM4, MK biosynthesis inhibitor, inhibited the formation of MRSA biofilm and it was screened against 1952 transposon mutants to elucidate mechanisms of action; however, no resistant mutants were found. Also, compound NM4 induced the production of reactive oxygen species (ROS) by blocking electron transfer in the oxidative phosphorylation pathway as observed by MRSA growth recovery using various ROS scavengers. An oxygen consumption assay also showed that NM4 blocks the oxygen consumption by MRSA, but the addition of menaquinone (MK) restores growth of MRSA. The NM4-treated MRSA induced the expression of catalase by more than 25%, as quantified by the native gel. A pulmonary murine model exhibited that NM4 significantly reduced bacterial lung load in mice without toxicity. An NM4-resistant USA300 strain was developed to attempt to identify the targets participating in the mechanism of resistance. Our results support that respiration and oxidative phosphorylation are potential targets for developing antimicrobial agents against MRSA. Altogether, our findings suggest the potential use of MK biosynthesis inhibitors as an effective antimicrobial agent against MRSA.
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Affiliation(s)
- Seoung-Ryoung Choi
- Department of Pathology and Microbiology, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Prabagaran Narayanasamy
- Department of Pathology and Microbiology, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
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12
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Jackson LK, Dailey TA, Anderle B, Warren MJ, Bergonia HA, Dailey HA, Phillips JD. Exploiting Differences in Heme Biosynthesis between Bacterial Species to Screen for Novel Antimicrobials. Biomolecules 2023; 13:1485. [PMID: 37892169 PMCID: PMC10604556 DOI: 10.3390/biom13101485] [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: 09/14/2023] [Revised: 10/02/2023] [Accepted: 10/03/2023] [Indexed: 10/29/2023] Open
Abstract
The final three steps of heme biogenesis exhibit notable differences between di- and mono-derm bacteria. The former employs the protoporphyrin-dependent (PPD) pathway, while the latter utilizes the more recently uncovered coproporphyrin-dependent (CPD) pathway. In order to devise a rapid screen for potential inhibitors that differentiate the two pathways, the genes associated with the protoporphyrin pathway in an Escherichia coli YFP strain were replaced with those for the CPD pathway from Staphylococcus aureus (SA) through a sliding modular gene replacement recombineering strategy to generate the E. coli strain Sa-CPD-YFP. Potential inhibitors that differentially target the pathways were identified by screening compound libraries against the YFP-producing Sa-CPD-YFP strain in comparison to a CFP-producing E. coli strain. Using a mixed strain assay, inhibitors targeting either the CPD or PPD heme pathways were identified through a decrease in one fluorescent signal but not the other. An initial screen identified both azole and prodigiosin-derived compounds that were shown to specifically target the CPD pathway and which led to the accumulation of coproheme, indicating that the main target of inhibition would appear to be the coproheme decarboxylase (ChdC) enzyme. In silico modeling highlighted that these inhibitors are able to bind within the active site of ChdC.
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Affiliation(s)
- Laurie K. Jackson
- Department of Internal Medicine, Division of Hematology, University of Utah, Salt Lake City, UT 84112, USA; (L.K.J.); (H.A.B.)
| | - Tammy A. Dailey
- Department of Microbiology, Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA (H.A.D.)
| | - Brenden Anderle
- WhiteTree Medical, 10437 S Jordan Gateway, South Jordan, UT 84095, USA;
| | - Martin J. Warren
- Quadram Institute Bioscience, Norwich Research Park, Norwich NR4 7UQ, UK;
| | - Hector A. Bergonia
- Department of Internal Medicine, Division of Hematology, University of Utah, Salt Lake City, UT 84112, USA; (L.K.J.); (H.A.B.)
| | - Harry A. Dailey
- Department of Microbiology, Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA (H.A.D.)
| | - John D. Phillips
- Department of Internal Medicine, Division of Hematology, University of Utah, Salt Lake City, UT 84112, USA; (L.K.J.); (H.A.B.)
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13
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Leasure CS, Grunenwald CM, Choby JE, Sauer JD, Skaar EP. Maintenance of heme homeostasis in Staphylococcus aureus through post-translational regulation of glutamyl-tRNA reductase. J Bacteriol 2023; 205:e0017123. [PMID: 37655914 PMCID: PMC10521356 DOI: 10.1128/jb.00171-23] [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: 06/01/2023] [Accepted: 06/30/2023] [Indexed: 09/02/2023] Open
Abstract
Staphylococcus aureus is an important human pathogen responsible for a variety of infections including skin and soft tissue infections, endocarditis, and sepsis. The combination of increasing antibiotic resistance in this pathogen and the lack of an efficacious vaccine underscores the importance of understanding how S. aureus maintains metabolic homeostasis in a variety of environments, particularly during infection. Within the host, S. aureus must regulate cellular levels of the cofactor heme to support enzymatic activities without encountering heme toxicity. Glutamyl tRNA reductase (GtrR), the enzyme catalyzing the first committed step in heme synthesis, is an important regulatory node of heme synthesis in Bacteria, Archaea, and Plantae. In many organisms, heme status negatively regulates the abundance of GtrR, controlling flux through the heme synthesis pathway. We identified two residues within GtrR, H32 and R214, that are important for GtrR-heme binding. However, in strains expressing either GtrRH32A or GtrRR214A, heme homeostasis was not perturbed, suggesting an alternative mechanism of heme synthesis regulation occurs in S. aureus. In this regard, we report that heme synthesis is regulated through phosphorylation and dephosphorylation of GtrR by the serine/threonine kinase Stk1 and the phosphatase Stp1, respectively. Taken together, these results suggest that the mechanisms governing staphylococcal heme synthesis integrate both the availability of heme and the growth status of the cell. IMPORTANCE Staphylococcus aureus represents a significant threat to human health. Heme is an iron-containing enzymatic cofactor that can be toxic at elevated levels. During infection, S. aureus must control heme levels to replicate and survive within the hostile host environment. We identified residues within a heme biosynthetic enzyme that are critical for heme binding in vitro; however, abrogation of heme binding is not sufficient to perturb heme homeostasis within S. aureus. This marks a divergence from previously reported mechanisms of heme-dependent regulation of the highly conserved enzyme glutamyl tRNA reductase (GtrR). Additionally, we link cell growth arrest to the modulation of heme levels through the post-translational regulation of GtrR by the kinase Stk1 and the phosphatase Stp1.
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Affiliation(s)
- Catherine S. Leasure
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Caroline M. Grunenwald
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Jacob E. Choby
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - John-Demian Sauer
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Eric P. Skaar
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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14
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Choi SR, Talmon GA, Hearne K, Woo J, Truong VL, Britigan BE, Narayanasamy P. Combination Therapy with Gallium Protoporphyrin and Gallium Nitrate Exhibits Enhanced Antimicrobial Activity In Vitro and In Vivo against Methicillin-Resistant Staphylococcus aureus. Mol Pharm 2023; 20:4058-4070. [PMID: 37471668 DOI: 10.1021/acs.molpharmaceut.3c00223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/22/2023]
Abstract
There is a major need for the development of new therapeutics to combat antibiotic-resistant Staphylococcus aureus. Recently, gallium (Ga)-based complexes have shown promising antimicrobial effects against various bacteria, including multidrug-resistant organisms, by targeting multiple heme/iron-dependent metabolic pathways. Among these, Ga protoporphyrin (GaPP) inhibits bacterial growth by targeting heme pathways, including aerobic respiration. Ga(NO3)3, an iron mimetic, disrupts elemental iron pathways. Here, we demonstrate the enhanced antimicrobial activity of the combination of GaPP and Ga(NO3)3 against methicillin-resistant S. aureus (MRSA) under iron-limited conditions, including small colony variants (SCV). This therapy demonstrated significant antimicrobial activity without inducing slow-growing SCV. We also observed that the combination of GaPP and Ga(NO3)3 inhibited the MRSA catalase but not above that seen with Ga(NO3)3 alone. Neither GaPP nor Ga(NO3)3 alone or their combination inhibited the dominant superoxide dismutase expressed (SodA) under the iron-limited conditions examined. Intranasal administration of the combination of the two compounds improved drug biodistribution in the lungs compared to intraperitoneal administration. In a murine MRSA lung infection model, we observed a significant increase in survival and decrease in MRSA lung CFUs in mice that received combination therapy with intranasal GaPP and Ga(NO3)3 compared to untreated control or mice receiving GaPP or Ga(NO3)3 alone. No drug-related toxicity was observed as assessed histologically in the spleen, lung, nasal cavity, and kidney for both single and repeated doses of 10 mg Ga /Kg of mice over 13 days. Our results strongly suggest that GaPP and Ga(NO3)3 in combination have excellent synergism and potential to be developed as a novel therapy for infections with S. aureus.
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Affiliation(s)
- Seoung-Ryoung Choi
- Department of Pathology and Microbiology, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Geoffrey A Talmon
- Department of Pathology and Microbiology, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Kenneth Hearne
- Aridis Pharmaceuticals, Los Gatos, California 95032, United States
| | - Jennifer Woo
- Aridis Pharmaceuticals, Los Gatos, California 95032, United States
| | - Vu L Truong
- Aridis Pharmaceuticals, Los Gatos, California 95032, United States
| | - Bradley E Britigan
- Department of Pathology and Microbiology, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
- Department of Internal Medicine, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
- Department of Internal Medicine and Research Service, Veterans Affairs Medical Center-Nebraska Western Iowa, Omaha, Nebraska 68105, United States
| | - Prabagaran Narayanasamy
- Department of Pathology and Microbiology, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
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15
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Maire J, Tandon K, Collingro A, van de Meene A, Damjanovic K, Gotze CR, Stephenson S, Philip GK, Horn M, Cantin NE, Blackall LL, van Oppen MJH. Colocalization and potential interactions of Endozoicomonas and chlamydiae in microbial aggregates of the coral Pocillopora acuta. SCIENCE ADVANCES 2023; 9:eadg0773. [PMID: 37196086 DOI: 10.1126/sciadv.adg0773] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 04/13/2023] [Indexed: 05/19/2023]
Abstract
Corals are associated with a variety of bacteria, which occur in the surface mucus layer, gastrovascular cavity, skeleton, and tissues. Some tissue-associated bacteria form clusters, termed cell-associated microbial aggregates (CAMAs), which are poorly studied. Here, we provide a comprehensive characterization of CAMAs in the coral Pocillopora acuta. Combining imaging techniques, laser capture microdissection, and amplicon and metagenome sequencing, we show that (i) CAMAs are located in the tentacle tips and may be intracellular; (ii) CAMAs contain Endozoicomonas (Gammaproteobacteria) and Simkania (Chlamydiota) bacteria; (iii) Endozoicomonas may provide vitamins to its host and use secretion systems and/or pili for colonization and aggregation; (iv) Endozoicomonas and Simkania occur in distinct, but adjacent, CAMAs; and (v) Simkania may receive acetate and heme from neighboring Endozoicomonas. Our study provides detailed insight into coral endosymbionts, thereby improving our understanding of coral physiology and health and providing important knowledge for coral reef conservation in the climate change era.
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Affiliation(s)
- Justin Maire
- School of BioSciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Kshitij Tandon
- School of BioSciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Astrid Collingro
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna 1030, Austria
| | - Allison van de Meene
- School of BioSciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Katarina Damjanovic
- Australian Institute of Marine Science, PMB No 3, Townsville, QLD 4810, Australia
| | - Cecilie Ravn Gotze
- School of BioSciences, The University of Melbourne, Parkville, VIC 3010, Australia
- Australian Institute of Marine Science, PMB No 3, Townsville, QLD 4810, Australia
| | - Sophie Stephenson
- Australian Institute of Marine Science, PMB No 3, Townsville, QLD 4810, Australia
| | - Gayle K Philip
- Melbourne Bioinformatics, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Matthias Horn
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna 1030, Austria
| | - Neal E Cantin
- Australian Institute of Marine Science, PMB No 3, Townsville, QLD 4810, Australia
| | - Linda L Blackall
- School of BioSciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Madeleine J H van Oppen
- School of BioSciences, The University of Melbourne, Parkville, VIC 3010, Australia
- Australian Institute of Marine Science, PMB No 3, Townsville, QLD 4810, Australia
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16
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Goojani HG, Besharati S, Chauhan P, Asseri AH, Lill H, Bald D. Cytochrome bd-I from Escherichia coli is catalytically active in the absence of the CydH subunit. FEBS Lett 2023; 597:547-556. [PMID: 36460943 DOI: 10.1002/1873-3468.14550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 10/27/2022] [Accepted: 11/22/2022] [Indexed: 12/04/2022]
Abstract
Cytochrome bd-I from Escherichia coli is a terminal oxidase in the respiratory chain that plays an important role under stress conditions. Cytochrome bd-I was thought to consist of the major subunits CydA and CydB plus the small CydX subunit. Recent high-resolution structures of cytochrome bd-I demonstrated the presence of an additional subunit, CydH/CydY (called CydH here), the function of which is unclear. In this report, we show that in the absence of CydH, cytochrome bd-I is catalytically active, can sustain bacterial growth and displays haem spectra and susceptibility for haem-binding inhibitors comparable to the wild-type enzyme. Removal of CydH did not elicit catalase activity of cytochrome bd-I in our experimental system. Taken together, in the absence of the CydH subunit cytochrome bd-I retained key enzymatic properties.
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Affiliation(s)
- Hojjat Ghasemi Goojani
- Faculty of Science, Amsterdam Institute for Life and Environment (A-LIFE), AIMMS, Vrije Universiteit Amsterdam, The Netherlands
| | - Samira Besharati
- Faculty of Science, Amsterdam Institute for Life and Environment (A-LIFE), AIMMS, Vrije Universiteit Amsterdam, The Netherlands
| | - Priyanka Chauhan
- Faculty of Science, Amsterdam Institute for Life and Environment (A-LIFE), AIMMS, Vrije Universiteit Amsterdam, The Netherlands
| | - Amer H Asseri
- Faculty of Science, Amsterdam Institute for Life and Environment (A-LIFE), AIMMS, Vrije Universiteit Amsterdam, The Netherlands.,Department of Biochemistry, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Holger Lill
- Faculty of Science, Amsterdam Institute for Life and Environment (A-LIFE), AIMMS, Vrije Universiteit Amsterdam, The Netherlands
| | - Dirk Bald
- Faculty of Science, Amsterdam Institute for Life and Environment (A-LIFE), AIMMS, Vrije Universiteit Amsterdam, The Netherlands
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17
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Islam S, Callender AC, Ho QN, Wakeman CA. Iron restriction induces the small-colony variant phenotype in Staphylococcus aureus. Front Microbiol 2022; 13:978859. [PMID: 36569073 PMCID: PMC9772265 DOI: 10.3389/fmicb.2022.978859] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Accepted: 11/21/2022] [Indexed: 12/13/2022] Open
Abstract
Pathogens such as Staphylococcus aureus must overcome host-induced selective pressures, including limited iron availability. To cope with the harsh conditions of the host environment, S. aureus can adapt its physiology in multiple ways. One of these adaptations is the fermenting small-colony variant (SCV) phenotype, which is known to be inherently tolerant to certain classes of antibiotics and heme toxicity. We hypothesized that SCVs might also behave uniquely in response to iron starvation since one of the major cellular uses of iron is the respiration machinery. In this study, a respiring strain of S. aureus and fermenting SCV strains were treated with different concentrations of the iron chelator, 2,2' dipyridyl (DIP). Our data demonstrate that a major impact of iron starvation in S. aureus is the repression of respiration and the induction of the SCV phenotype. We demonstrate that the SCV phenotype transiently induced by iron starvation mimics the aminoglycoside recalcitrance exhibited by genetic SCVs. Furthermore, prolonged growth in iron starvation promotes increased emergence of stable aminoglycoside-resistant SCVs relative to the naturally occurring subpopulation of SCVs within an S. aureus community. These findings may have relevance to physiological and evolutionary processes occurring within bacterial populations infecting iron-limited host environments.
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Affiliation(s)
| | | | | | - Catherine A. Wakeman
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, United States
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18
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Donegan RK. The role of host heme in bacterial infection. Biol Chem 2022; 403:1017-1029. [PMID: 36228088 DOI: 10.1515/hsz-2022-0192] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Accepted: 09/14/2022] [Indexed: 11/15/2022]
Abstract
Heme is an indispensable cofactor for almost all aerobic life, including the human host and many bacterial pathogens. During infection, heme and hemoproteins are the largest source of bioavailable iron, and pathogens have evolved various heme acquisition pathways to satisfy their need for iron and heme. Many of these pathways are regulated transcriptionally by intracellular iron levels, however, host heme availability and intracellular heme levels have also been found to regulate heme uptake in some species. Knowledge of these pathways has helped to uncover not only how these bacteria incorporate host heme into their metabolism but also provided insight into the importance of host heme as a nutrient source during infection. Within this review is covered multiple aspects of the role of heme at the host pathogen interface, including the various routes of heme biosynthesis, how heme is sequestered by the host, and how heme is scavenged by bacterial pathogens. Also discussed is how heme and hemoproteins alter the behavior of the host immune system and bacterial pathogens. Finally, some unanswered questions about the regulation of heme uptake and how host heme is integrated into bacterial metabolism are highlighted.
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Affiliation(s)
- Rebecca K Donegan
- Department of Chemistry, Barnard College, 3009 Broadway, New York, NY, 10027, USA
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19
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Zhou S, Rao Y, Li J, Huang Q, Rao X. Staphylococcus aureus small-colony variants: Formation, infection, and treatment. Microbiol Res 2022; 260:127040. [DOI: 10.1016/j.micres.2022.127040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 04/10/2022] [Accepted: 04/11/2022] [Indexed: 10/18/2022]
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20
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Van Alst AJ, Demey LM, DiRita VJ. Vibrio cholerae requires oxidative respiration through the bd-I and cbb3 oxidases for intestinal proliferation. PLoS Pathog 2022; 18:e1010102. [PMID: 35500027 PMCID: PMC9109917 DOI: 10.1371/journal.ppat.1010102] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 05/16/2022] [Accepted: 04/05/2022] [Indexed: 01/05/2023] Open
Abstract
Vibrio cholerae respires both aerobically and anaerobically and, while oxygen may be available to it during infection, other terminal electron acceptors are proposed for population expansion during infection. Unlike gastrointestinal pathogens that stimulate significant inflammation leading to elevated levels of oxygen or alternative terminal electron acceptors, V. cholerae infections are not understood to induce a notable inflammatory response. To ascertain the respiration requirements of V. cholerae during infection, we used Multiplex Genome Editing by Natural Transformation (MuGENT) to create V. cholerae strains lacking aerobic or anaerobic respiration. V. cholerae strains lacking aerobic respiration were attenuated in infant mice 105-fold relative to wild type, while strains lacking anaerobic respiration had no colonization defect, contrary to earlier work suggesting a role for anaerobic respiration during infection. Using several approaches, including one we developed for this work termed Comparative Multiplex PCR Amplicon Sequencing (CoMPAS), we determined that the bd-I and cbb3 oxidases are essential for small intestinal colonization of V. cholerae in the infant mouse. The bd-I oxidase was also determined as the primary oxidase during growth outside the host, making V. cholerae the only example of a Gram-negative bacterial pathogen in which a bd-type oxidase is the primary oxidase for energy acquisition inside and outside of a host. The bacterium that causes cholera, Vibrio cholerae, can grow with or without oxygen. When growing without oxygen it may use other molecules that serve the same purpose as oxygen, acting as a terminal electron acceptor in an energy-generating process known as respiration. Given the largely anaerobic nature of the gastrointestinal tract, and the lack of significant inflammation during cholera infection, a process that can stimulate elevated levels of oxygen and other terminal electron acceptors, we sought to understand the respiratory mechanisms of V. cholerae during infection. We used a powerful genome-editing method to construct mutant strains of V. cholerae lacking some or all of the complement of proteins required for aerobic or anaerobic respiration. By analyzing these mutants in the laboratory and in intestinal colonization of infant mice, we determined that the ability to respire without oxygen is completely dispensable for V. cholerae to thrive during infection. We determined that two of the four oxygen-dependent respiration mechanisms are essential for V. cholerae to grow during infection, with the other two dispensable for wild type levels of colonization.
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Affiliation(s)
- Andrew J. Van Alst
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, United States of America
| | - Lucas M. Demey
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, United States of America
| | - Victor J. DiRita
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, United States of America
- * E-mail:
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21
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Catabolic Ornithine Carbamoyltransferase Activity Facilitates Growth of Staphylococcus aureus in Defined Medium Lacking Glucose and Arginine. mBio 2022; 13:e0039522. [PMID: 35475645 PMCID: PMC9239276 DOI: 10.1128/mbio.00395-22] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Previous studies have found that arginine biosynthesis in Staphylococcus aureus is repressed via carbon catabolite repression (CcpA), and proline is used as a precursor. Unexpectedly, however, robust growth of S. aureus is not observed in complete defined medium lacking both glucose and arginine (CDM-R). Mutants able to grow on agar-containing defined medium lacking arginine (CDM-R) were selected and found to contain mutations within ahrC, encoding the canonical arginine biosynthesis pathway repressor (AhrC), or single nucleotide polymorphisms (SNPs) upstream of the native arginine deiminase (ADI) operon arcA1B1D1C1. Reverse transcription-PCR (RT-PCR) studies found that mutations within ccpA or ahrC or SNPs identified upstream of arcA1B1D1C1 increased the transcription of both arcB1 and argGH, encoding ornithine carbamoyltransferase and argininosuccinate synthase/lyase, respectively, facilitating arginine biosynthesis. Furthermore, mutations within the AhrC homologue argR2 facilitated robust growth within CDM-R. Complementation with arcB1 or arcA1B1D1C1, but not argGH, rescued growth in CDM-R. Finally, supplementation of CDM-R with ornithine stimulated growth, as did mutations in genes (proC and rocA) that presumably increased the pyrroline-5-carboxylate and ornithine pools. Collectively, these data suggest that the transcriptional regulation of ornithine carbamoyltransferase and, in addition, the availability of intracellular ornithine pools regulate arginine biosynthesis in S. aureus in the absence of glucose. Surprisingly, ~50% of clinical S. aureus isolates were able to grow in CDM-R. These data suggest that S. aureus is selected to repress arginine biosynthesis in environments with or without glucose; however, mutants may be readily selected that facilitate arginine biosynthesis and growth in specific environments lacking arginine.
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22
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Michalska K, Rychłowski M, Krupińska M, Szewczyk G, Sarna T, Nakonieczna J. Gallium Mesoporphyrin IX-Mediated Photodestruction: A Pharmacological Trojan Horse Strategy To Eliminate Multidrug-Resistant Staphylococcus aureus. Mol Pharm 2022; 19:1434-1448. [PMID: 35416046 PMCID: PMC9066410 DOI: 10.1021/acs.molpharmaceut.1c00993] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
![]()
One of the factors
determining efficient antimicrobial photodynamic
inactivation (aPDI) is the accumulation of a light-activated compound,
namely, a photosensitizer (PS). Targeted PS recognition is the approach
based on the interaction between the membrane receptor on the bacterial
surface and the PS, whereas the compound is efficiently accumulated
by the same mechanism as the natural ligand. In this study, we showed
that gallium mesoporphyrin IX (Ga3+MPIX) provided dual
functionality—iron metabolism disruption and PS properties
in aPDI. Ga3+MPIX induced efficient (>5log10 reduction in CFU/mL) bacterial photodestruction with excitation
in the area of Q band absorption with relatively low eukaryotic cytotoxicity
and phototoxicity. The Ga3+MPIX is recognized by the same
systems as haem by the iron-regulated surface determinant (Isd). However,
the impairment in the ATPase of the haem detoxification efflux pump
was the most sensitive to the Ga3+MPIX-mediated aPDI phenotype.
This indicates that changes within the metalloporphyrin structure
(vinyl vs ethyl groups) did not significantly alter the properties
of recognition of the compound but influenced its biophysical properties.
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Affiliation(s)
- Klaudia Michalska
- Laboratory of Photobiology and Molecular Diagnostics, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Abrahama 58, Gdansk 80-307, Poland
| | - Michał Rychłowski
- Laboratory of Virus Molecular Biology, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Abrahama 58, Gdansk 80-307, Poland
| | - Martyna Krupińska
- Laboratory of Photobiology and Molecular Diagnostics, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Abrahama 58, Gdansk 80-307, Poland
| | - Grzegorz Szewczyk
- Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, Krakow 30-387, Poland
| | - Tadeusz Sarna
- Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, Krakow 30-387, Poland
| | - Joanna Nakonieczna
- Laboratory of Photobiology and Molecular Diagnostics, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Abrahama 58, Gdansk 80-307, Poland
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23
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Rivera-Lugo R, Deng D, Anaya-Sanchez A, Tejedor-Sanz S, Tang E, Reyes Ruiz VM, Smith HB, Titov DV, Sauer JD, Skaar EP, Ajo-Franklin CM, Portnoy DA, Light SH. Listeria monocytogenes requires cellular respiration for NAD + regeneration and pathogenesis. eLife 2022; 11:e75424. [PMID: 35380108 PMCID: PMC9094743 DOI: 10.7554/elife.75424] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 04/04/2022] [Indexed: 11/20/2022] Open
Abstract
Cellular respiration is essential for multiple bacterial pathogens and a validated antibiotic target. In addition to driving oxidative phosphorylation, bacterial respiration has a variety of ancillary functions that obscure its contribution to pathogenesis. We find here that the intracellular pathogen Listeria monocytogenes encodes two respiratory pathways which are partially functionally redundant and indispensable for pathogenesis. Loss of respiration decreased NAD+ regeneration, but this could be specifically reversed by heterologous expression of a water-forming NADH oxidase (NOX). NOX expression fully rescued intracellular growth defects and increased L. monocytogenes loads >1000-fold in a mouse infection model. Consistent with NAD+ regeneration maintaining L. monocytogenes viability and enabling immune evasion, a respiration-deficient strain exhibited elevated bacteriolysis within the host cytosol and NOX expression rescued this phenotype. These studies show that NAD+ regeneration represents a major role of L. monocytogenes respiration and highlight the nuanced relationship between bacterial metabolism, physiology, and pathogenesis.
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Affiliation(s)
- Rafael Rivera-Lugo
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - David Deng
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Andrea Anaya-Sanchez
- Graduate Group in Microbiology, University of California, BerkeleyBerkeleyUnited States
| | - Sara Tejedor-Sanz
- Department of Biosciences, Rice UniversityHoustonUnited States
- The Molecular Foundry, Lawrence Berkeley National LaboratoryBerkeleyUnited States
| | - Eugene Tang
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Valeria M Reyes Ruiz
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical CenterNashvilleUnited States
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical CenterNashvilleUnited States
| | - Hans B Smith
- Department of Medical Microbiology and Immunology, University of Wisconsin-MadisonMadisonUnited States
| | - Denis V Titov
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
- Department of Nutritional Sciences and Toxicology, University of California, BerkeleyBerkeleyUnited States
- Center for Computational Biology, University of California, BerkeleyBerkeleyUnited States
| | - John-Demian Sauer
- Department of Medical Microbiology and Immunology, University of Wisconsin-MadisonMadisonUnited States
| | - Eric P Skaar
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical CenterNashvilleUnited States
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical CenterNashvilleUnited States
| | - Caroline M Ajo-Franklin
- Department of Biosciences, Rice UniversityHoustonUnited States
- The Molecular Foundry, Lawrence Berkeley National LaboratoryBerkeleyUnited States
| | - Daniel A Portnoy
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
- Department of Plant and Microbial Biology, University of California, BerkeleyBerkeleyUnited States
| | - Samuel H Light
- Department of Microbiology, University of ChicagoChicagoUnited States
- Duchossois Family Institute, University of ChicagoChicagoUnited States
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Tobramycin Stress Induced Differential Gene Expression in Acinetobacter baumannii. Curr Microbiol 2022; 79:88. [PMID: 35129693 DOI: 10.1007/s00284-022-02788-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 01/24/2022] [Indexed: 11/03/2022]
Abstract
Acinetobacter baumannii is a multidrug-resistant bacteria responsible for nosocomial infections with significant fatality rates globally. Therapeutic failure and relapse of infection has been associated with persister cells formation which can also lead to resistance in A. baumannii. In the present study, we observed that A. baumannii ATCC 17978 in exponential phase survived lethal concentrations of amikacin, rifampicin and ciprofloxacin by generating persister cells but was unable to survive tobramycin treatment. The transcriptome of A. baumannii ATCC 17978 was analyzed following exposure to a high concentration of tobramycin (10 × MIC) for a short period of time to study the possible mechanisms responsible for lethality. Tobramycin reduced the expression of genes involved in energy production (nuoH, nuoN, nuoM, cydA, sucC), oxidative stress protection (tauD, cysD), and nutrition uptake (ompW) significantly. In addition, hemerythrin (non-heme di-iron oxygen-binding protein) was found to be the most downregulated gene in response to tobramycin which needs to be further studied for its role in susceptibility to antibiotics. Tobramycin upregulated the expression of genes that are mainly involved in stress response (leucine catabolism, DNA repair and HicAB toxin-antitoxin system). The differentially expressed genes highlighted in the study provided insight into the probable molecular mechanism of tobramycin-induced cell death and revealed some novel targets that can be explored further for their potential to control A. baumannii.
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Wassmann CS, Rolsted AP, Lyngsie MC, Puig ST, Kronborg T, Vestergaard M, Ingmer H, Pontoppidan SP, Klitgaard JK. The menaquinone pathway is important for susceptibility of Staphylococcus aureus to the antibiotic adjuvant, cannabidiol. Microbiol Res 2022; 257:126974. [DOI: 10.1016/j.micres.2022.126974] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 01/14/2022] [Accepted: 01/17/2022] [Indexed: 01/12/2023]
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26
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Wang X, Li W, Wang W, Wang S, Xu T, Chen J, Zhang W. Involvement of Small Colony Variant-Related Heme Biosynthesis Genes in Staphylococcus aureus Persister Formation in vitro. Front Microbiol 2021; 12:756809. [PMID: 35003000 PMCID: PMC8733728 DOI: 10.3389/fmicb.2021.756809] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 11/24/2021] [Indexed: 11/17/2022] Open
Abstract
Background: Persisters are important reasons for persistent infections, and they can lead to antibiotic treatment failure in patients and consequently chronic infection. Staphylococcus aureus small colony variants (SCVs) have been shown to be related to persistent infection. Mutations in the genes of the heme biosynthesis pathway lead to the formation of SCVs. However, the relationship between heme production genes and persister has not been tested. Methods: HemA and hemB were knocked out by allelic replacement from S. aureus strain USA500 separately, and then, the heme deficiency was complemented by overexpression of related genes and the addition of hemin. The stress-related persister assay was conducted. RNA-sequencing was performed to find genes and pathways involved in heme-related persister formation, and relative genes and operons were further knocked out and overexpressed to confirm their role in each process. Results: We found that heme biosynthesis deficiency can lead to decreased persister. After complementing the corresponding genes or hemin, the persister levels could be restored. RNA-seq on knockout strains showed that various metabolic pathways were influenced, such as energy metabolism, amino acid metabolism, carbohydrate metabolism, and membrane transport. Overexpression of epiF and operon asp23 could restore USA500∆hemA persister formation under acid stress. Knocking out operon arc in USA500∆hemA could further reduce USA500∆hemA persister formation under acid and oxidative stress. Conclusion: Heme synthesis has a role in S. aureus persister formation.
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Affiliation(s)
- Xuyang Wang
- Department of Infectious Diseases, National Medical Center for Infectious Diseases, Shanghai Key Laboratory of Infectious Diseases and Biosafety Emergency Response, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Weizheng Li
- Department of Infectious Diseases, Putuo Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Wenjie Wang
- Department of Infectious Diseases, National Medical Center for Infectious Diseases, Shanghai Key Laboratory of Infectious Diseases and Biosafety Emergency Response, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Shiyong Wang
- Department of Infectious Diseases, National Medical Center for Infectious Diseases, Shanghai Key Laboratory of Infectious Diseases and Biosafety Emergency Response, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Tao Xu
- Department of Infectious Diseases, National Medical Center for Infectious Diseases, Shanghai Key Laboratory of Infectious Diseases and Biosafety Emergency Response, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Jiazhen Chen
- Department of Infectious Diseases, National Medical Center for Infectious Diseases, Shanghai Key Laboratory of Infectious Diseases and Biosafety Emergency Response, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Wenhong Zhang
- Department of Infectious Diseases, National Medical Center for Infectious Diseases, Shanghai Key Laboratory of Infectious Diseases and Biosafety Emergency Response, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
- National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
- Key Laboratory of Medical Molecular Virology (MOE/MOH) Shanghai Medical College, Fudan University, Shanghai, China
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27
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Heme-Dependent Siderophore Utilization Promotes Iron-Restricted Growth of the Staphylococcus aureus hemB Small-Colony Variant. J Bacteriol 2021; 203:e0045821. [PMID: 34606375 DOI: 10.1128/jb.00458-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Respiration-deficient Staphylococcus aureus small-colony variants (SCVs) frequently cause persistent infections, which necessitates they acquire iron, yet how SCVs obtain iron remains unknown. To address this, we created a stable hemB mutant from S. aureus USA300 strain LAC. The hemB SCV utilized exogenously supplied hemin but was attenuated for growth under conditions of iron starvation. Transcriptome sequencing (RNA-seq) showed that both wild-type (WT) S. aureus and the hemB mutant sense and respond to iron starvation; however, growth assays show that the hemB mutant is defective for siderophore-mediated iron acquisition. Indeed, the hemB SCV demonstrated limited utilization of endogenous staphyloferrin B or exogenously provided staphyloferrin A, deferoxamine mesylate (Desferal), and epinephrine. Direct measurement of intracellular ATP in hemB and WT S. aureus revealed that both strains can generate comparable levels of ATP during exponential growth, suggesting defects in ATP production cannot account for the inability to efficiently utilize siderophores. Defective siderophore utilization by hemB bacteria was also evident in vivo, as administration of Desferal failed to promote hemB bacterial growth in every organ analyzed except for the kidneys. In support of the hypothesis that S. aureus accesses heme in kidney abscesses, in vitro analyses revealed that increased hemin availability enables hemB bacteria to utilize siderophores for growth when iron availability is restricted. Taken together, our data support the conclusion that hemin is used not only as an iron source itself but also as a nutrient that promotes utilization of siderophore-iron complexes. IMPORTANCE S. aureus small-colony variants (SCVs) are associated with chronic recurrent infection and worsened clinical outcome. SCVs persist within the host despite administration of antibiotics. This study yields insight into how S. aureus SCVs acquire iron, which during infection of a host is a difficult-to-acquire metal nutrient. Under hemin-limited conditions, hemB S. aureus is impaired for siderophore-dependent growth, and in agreement, murine infection indicates that hemin-deficient SCVs meet their nutritional requirement for iron through utilization of hemin. Importantly, we demonstrate that hemB SCVs rely upon hemin as a nutrient to promote siderophore utilization. Therefore, perturbation of heme biosynthesis and/or utilization represents a viable to strategy to mitigate the ability of SCV bacteria to acquire siderophore-bound iron during infection.
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Cesinger MR, Schwardt NH, Halsey CR, Thomason MK, Reniere ML. Investigating the Roles of Listeria monocytogenes Peroxidases in Growth and Virulence. Microbiol Spectr 2021; 9:e0044021. [PMID: 34287055 PMCID: PMC8552690 DOI: 10.1128/spectrum.00440-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 06/23/2021] [Indexed: 11/25/2022] Open
Abstract
Bacteria have necessarily evolved a protective arsenal of proteins to contend with peroxides and other reactive oxygen species generated in aerobic environments. Listeria monocytogenes encounters an onslaught of peroxide both in the environment and during infection of the mammalian host, where it is the causative agent of the foodborne illness listeriosis. Despite the importance of peroxide for the immune response to bacterial infection, the strategy by which L. monocytogenes protects against peroxide toxicity has yet to be illuminated. Here, we investigated the expression and essentiality of all the peroxidase-encoding genes during L. monocytogenes growth in vitro and during infection of murine cells in tissue culture. We found that chdC and kat were required for aerobic growth in vitro, and fri and ahpA were each required for L. monocytogenes to survive acute peroxide stress. Despite increased expression of fri, ahpA, and kat during infection of macrophages, only fri proved necessary for cytosolic growth. In contrast, the proteins encoded by lmo0367, lmo0983, tpx, lmo1609, and ohrA were dispensable for aerobic growth, acute peroxide detoxification, and infection. Together, our results provide insight into the multifaceted L. monocytogenes peroxide detoxification strategy and demonstrate that L. monocytogenes encodes a functionally diverse set of peroxidase enzymes. IMPORTANCE Listeria monocytogenes is a facultative intracellular pathogen and the causative agent of the foodborne illness listeriosis. L. monocytogenes must contend with reactive oxygen species generated extracellularly during aerobic growth and intracellularly by the host immune system. However, the mechanisms by which L. monocytogenes defends against peroxide toxicity have not yet been defined. Here, we investigated the roles of each of the peroxidase-encoding genes in L. monocytogenes growth, peroxide stress response, and virulence in mammalian cells.
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Affiliation(s)
- Monica R. Cesinger
- Department of Microbiology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Nicole H. Schwardt
- Department of Microbiology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Cortney R. Halsey
- Department of Microbiology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Maureen K. Thomason
- Department of Microbiology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Michelle L. Reniere
- Department of Microbiology, University of Washington School of Medicine, Seattle, Washington, USA
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29
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Quantifying Staphylococcus aureus Membrane Potential Using Flow Cytometry. Methods Mol Biol 2021. [PMID: 34264465 DOI: 10.1007/978-1-0716-1550-8_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Quantifying fluorescent markers in cell populations using flow cytometry has been a powerful technological advance. Fluorescent properties of cyanine dyes coupled with flow cytometry allow investigators to monitor the membrane potential (MP), an important component of the proton motive force (PMF). MP (or ΔΨ) is the electrical potential across the cell membrane. The other component of the PMF is ΔpH, or the difference in interior and exterior proton concentrations. MP plays a critical role in bacterial physiology. In Staphylococcus aureus, MP is required for generation of ATP, regulating autolytic activity, maintaining ion homeostasis, and resistance to some classes of antibiotics. This protocol exploits unique spectral and physical properties of the cyanine-based molecule diethyloxacarbocyanine iodide, or DiOC, and flow cytometry technology to quantify MP in S. aureus. This assay has been used by researchers to define the electron transport chain of S. aureus as well as determine how intrinsic and extrinsic factors affect MP.
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30
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Rapacka-Zdończyk A, Woźniak A, Michalska K, Pierański M, Ogonowska P, Grinholc M, Nakonieczna J. Factors Determining the Susceptibility of Bacteria to Antibacterial Photodynamic Inactivation. Front Med (Lausanne) 2021; 8:642609. [PMID: 34055830 PMCID: PMC8149737 DOI: 10.3389/fmed.2021.642609] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 04/12/2021] [Indexed: 01/23/2023] Open
Abstract
Photodynamic inactivation of microorganisms (aPDI) is an excellent method to destroy antibiotic-resistant microbial isolates. The use of an exogenous photosensitizer or irradiation of microbial cells already equipped with endogenous photosensitizers makes aPDI a convenient tool for treating the infections whenever technical light delivery is possible. Currently, aPDI research carried out on a vast repertoire of depending on the photosensitizer used, the target microorganism, and the light delivery system shows efficacy mostly on in vitro models. The search for mechanisms underlying different responses to photodynamic inactivation of microorganisms is an essential issue in aPDI because one niche (e.g., infection site in a human body) may have bacterial subpopulations that will exhibit different susceptibility. Rapidly growing bacteria are probably more susceptible to aPDI than persister cells. Some subpopulations can produce more antioxidant enzymes or have better performance due to efficient efflux pumps. The ultimate goal was and still is to identify and characterize molecular features that drive the efficacy of antimicrobial photodynamic inactivation. To this end, we examined several genetic and biochemical characteristics, including the presence of individual genetic elements, protein activity, cell membrane content and its physical properties, the localization of the photosensitizer, with the result that some of them are important and others do not appear to play a crucial role in the process of aPDI. In the review, we would like to provide an overview of the factors studied so far in our group and others that contributed to the aPDI process at the cellular level. We want to challenge the question, is there a general pattern of molecular characterization of aPDI effectiveness? Or is it more likely that a photosensitizer-specific pattern of molecular characteristics of aPDI efficacy will occur?
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Affiliation(s)
| | - Agata Woźniak
- Laboratory of Molecular Diagnostics, Intercollegiate Faculty of Biotechnology, University of Gdańsk and Medical University of Gdańsk, Gdańsk, Poland
| | - Klaudia Michalska
- Laboratory of Molecular Diagnostics, Intercollegiate Faculty of Biotechnology, University of Gdańsk and Medical University of Gdańsk, Gdańsk, Poland
| | - Michał Pierański
- Laboratory of Molecular Diagnostics, Intercollegiate Faculty of Biotechnology, University of Gdańsk and Medical University of Gdańsk, Gdańsk, Poland
| | - Patrycja Ogonowska
- Laboratory of Molecular Diagnostics, Intercollegiate Faculty of Biotechnology, University of Gdańsk and Medical University of Gdańsk, Gdańsk, Poland
| | - Mariusz Grinholc
- Laboratory of Molecular Diagnostics, Intercollegiate Faculty of Biotechnology, University of Gdańsk and Medical University of Gdańsk, Gdańsk, Poland
| | - Joanna Nakonieczna
- Laboratory of Molecular Diagnostics, Intercollegiate Faculty of Biotechnology, University of Gdańsk and Medical University of Gdańsk, Gdańsk, Poland
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31
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André AC, Debande L, Marteyn BS. The selective advantage of facultative anaerobes relies on their unique ability to cope with changing oxygen levels during infection. Cell Microbiol 2021; 23:e13338. [PMID: 33813807 DOI: 10.1111/cmi.13338] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 03/18/2021] [Accepted: 03/19/2021] [Indexed: 12/19/2022]
Abstract
Bacteria, including those that are pathogenic, have been generally classified according to their ability to survive and grow in the presence or absence of oxygen: aerobic and anaerobic bacteria, respectively. Strict aerobes require oxygen to grow (e.g., Neisseria), and strict anaerobes grow exclusively without, and do not survive oxygen exposure (e.g., Clostridia); aerotolerant bacteria (e.g., Lactobacilli) are insensitive to oxygen exposure. Facultative anaerobes (e.g., E. coli) have the unique ability to grow in the presence or in the absence of oxygen and are thus well-adapted to these changing conditions, which may constitute an underestimated selective advantage for infection. In the WHO antibiotic-resistant 'priority pathogens' list, facultative anaerobes are overrepresented (8 among 12 listed pathogens), consistent with clinical studies performed in populations particularly susceptible to infectious diseases. Bacteria aerobic respiratory chain plays a central role in oxygen consumption, leading to the formation of hypoxic infectious sites (infectious hypoxia). Facultative anaerobes have developed a wide diversity of aerotolerance and anaerotolerance strategies in vivo. However, at a single cell level, the modulation of the intracellular oxygen level in host infected cells remains elusive and will be discussed in this review. In conclusion, the ability of facultative bacteria to evolve in the presence or the absence of oxygen is essential for their virulence strategy and constitute a selective advantage. TAKE AWAY: Most life-threatening pathogenic bacteria are facultative anaerobes. Only facultative anaerobes are aerotolerant, anaerotolerant and capable of consuming O2 . Facultative anaerobes induce and are well adapted to cellular hypoxia.
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Affiliation(s)
- Antonin C André
- Institut de Biologie Moléculaire et Cellulaire, Architecture et Réactivité de l'ARN, CNRS UPR9002, Université de Strasbourg, Strasbourg, France.,Université de Paris, Paris, France
| | - Lorine Debande
- Institut de Biologie Moléculaire et Cellulaire, Architecture et Réactivité de l'ARN, CNRS UPR9002, Université de Strasbourg, Strasbourg, France
| | - Benoit S Marteyn
- Institut de Biologie Moléculaire et Cellulaire, Architecture et Réactivité de l'ARN, CNRS UPR9002, Université de Strasbourg, Strasbourg, France.,University of Strasbourg Institute for Advanced Study (USIAS), Strasbourg, France.,Institut Pasteur, Unité de Pathogenèse des Infections Vasculaires, Paris Cedex 15, France
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32
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Pandey S, Sahukhal GS, Elasri MO. The msaABCR Operon Regulates Persister Formation by Modulating Energy Metabolism in Staphylococcus aureus. Front Microbiol 2021; 12:657753. [PMID: 33936014 PMCID: PMC8079656 DOI: 10.3389/fmicb.2021.657753] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Accepted: 03/26/2021] [Indexed: 11/24/2022] Open
Abstract
Staphylococcus aureus is a major human pathogen that causes chronic, systemic infections, and the recalcitrance of these infections is mainly due to the presence of persister cells, which are a bacterial subpopulation that exhibits extreme, yet transient, antibiotic tolerance accompanied by a transient halt in growth. However, upon cessation of antibiotic treatment, a resumption in growth of persister cells causes recurrence of infections and treatment failure. Previously, we reported the involvement of msaABCR in several important staphylococcal phenotypes, including the formation of persister cells. Additionally, observations of the regulation of several metabolic genes by the msaABCR operon in transcriptomics and proteomics analyses have suggested its role in the metabolic activities of S. aureus. Given the importance of metabolism in persister formation as our starting point, in this study we demonstrated how the msaABCR operon regulates energy metabolism and subsequent antibiotic tolerance. We showed that deletion of the msaABCR operon results in increased tricarboxylic acid (TCA) cycle activity, accompanied by increased cellular ATP content and higher NADH content in S. aureus cells. We also showed that msaABCR (through MsaB) represses the ccpE and ndh2 genes, thereby regulating TCA cycle activity and the generation of membrane potential, respectively. Together, the observations from this study led to the conclusion that msaABCR operon deletion induces a metabolically hyperactive state, leading to decreased persister formation in S. aureus.
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Affiliation(s)
- Shanti Pandey
- Center for Molecular and Cellular Biosciences, The University of Southern Mississippi, Hattiesburg, MS, United States
| | - Gyan S Sahukhal
- Center for Molecular and Cellular Biosciences, The University of Southern Mississippi, Hattiesburg, MS, United States
| | - Mohamed O Elasri
- Center for Molecular and Cellular Biosciences, The University of Southern Mississippi, Hattiesburg, MS, United States
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33
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Herrin BE, Islam S, Rentschler KN, Pert LH, Kopanski SP, Wakeman CA. Haem toxicity provides a competitive advantage to the clinically relevant Staphylococcus aureus small colony variant phenotype. MICROBIOLOGY (READING, ENGLAND) 2021; 167:001044. [PMID: 33749578 PMCID: PMC8289220 DOI: 10.1099/mic.0.001044] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 02/18/2021] [Indexed: 11/18/2022]
Abstract
Microorganisms encounter toxicities inside the host. Many pathogens exist as subpopulations to maximize survivability. Subpopulations of Staphylococcus aureus include antibiotic-tolerant small colony variants (SCVs). These mutants often emerge following antibiotic treatment but can be present in infections prior to antibiotic exposure. We hypothesize that haem toxicity in the host selects for respiration-deficient S. aureus SCVs in the absence of antibiotics. We demonstrate that some but not all respiration-deficient SCV phenotypes are more protective than the haem detoxification system against transient haem exposure, indicating that haem toxicity in the host may contribute to the dominance of menaquinone-deficient and haem-deficient SCVs prior to antibiotic treatment.
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Affiliation(s)
- Brittany E. Herrin
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, USA
- Present address: Department of Biology, Indiana University, Bloomington, IN, USA
| | - Shariful Islam
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, USA
| | | | - Lauren H. Pert
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, USA
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A Novel Enterococcus faecalis Heme Transport Regulator (FhtR) Senses Host Heme To Control Its Intracellular Homeostasis. mBio 2021; 12:mBio.03392-20. [PMID: 33531389 PMCID: PMC7858072 DOI: 10.1128/mbio.03392-20] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Enterococcus faecalis, a normal and harmless colonizer of the human intestinal flora can cause severe infectious diseases in immunocompromised patients, particularly those that have been heavily treated with antibiotics. Therefore, it is important to understand the factors that promote its resistance and its virulence. E. faecalis, which cannot synthesize heme, an essential but toxic metabolite, needs to scavenge this molecule from the host to respire and fight stress generated by oxidants. Enterococcus faecalis is a commensal Gram-positive pathogen found in the intestines of mammals and is also a leading cause of severe infections occurring mainly among antibiotic-treated dysbiotic hospitalized patients. Like most intestinal bacteria, E. faecalis does not synthesize heme (in this report, heme refers to iron protoporphyrin IX regardless of the iron redox state). Nevertheless, environmental heme can improve E. faecalis fitness by activating respiration metabolism and a catalase that limits hydrogen peroxide stress. Since free heme also generates toxicity, its intracellular levels need to be strictly controlled. Here, we describe a unique transcriptional regulator, FhtR (named FhtR for faecalis heme transport regulator), which manages heme homeostasis by controlling an HrtBA-like efflux pump (named HrtBAEf for the HrtBA from E. faecalis). We show that FhtR, by managing intracellular heme concentration, regulates the functional expression of the heme-dependent catalase A (KatA), thus participating in heme detoxification. The biochemical features of FhtR binding to DNA, and its interaction with heme that induces efflux, are characterized. The FhtR-HrtBAEf system is shown to be relevant in a mouse intestinal model. We further show that FhtR senses heme from blood and hemoglobin but also from crossfeeding by Escherichia coli. These findings bring to light the central role of heme sensing by FhtR in response to heme fluctuations within the gastrointestinal tract, which allow this pathogen to limit heme toxicity while ensuring expression of an oxidative defense system.
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35
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Nguyen MT, Matsuo M, Niemann S, Herrmann M, Götz F. Lipoproteins in Gram-Positive Bacteria: Abundance, Function, Fitness. Front Microbiol 2020; 11:582582. [PMID: 33042100 PMCID: PMC7530257 DOI: 10.3389/fmicb.2020.582582] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Accepted: 08/27/2020] [Indexed: 12/14/2022] Open
Abstract
When one thinks of the Gram+ cell wall, the peptidoglycan (PG) scaffold in particular comes to mind. However, the cell wall also consists of many other components, for example those that are covalently linked to the PG: the wall teichoic acid and the cell wall proteins tethered by the sortase. In addition, there are completely different molecules that are anchored in the cytoplasmic membrane and span the cell wall. These are lipoteichoic acids and bacterial lipoproteins (Lpp). The latter are in the focus of this review. Lpp are present in almost all bacteria. They fulfill a wealth of different tasks. They represent the window to the outside world by recognizing nutrients and incorporating them into the bacterial cell via special transport systems. Furthermore, they perform very diverse and special tasks such as acting as chaperonin, as cyclomodulin, contributing to invasion of host cells or uptake of plasmids via conjugation. All these functions are taken over by the protein part. Nevertheless, the lipid part of the Lpp plays an as important role as the protein part. It is the released lipoproteins and derived lipopeptides that massively modulate our immune system and ultimately play an important role in immune tolerance or non-tolerance. All these varied activities of the Lpp are considered in this review article.
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Affiliation(s)
- Minh-Thu Nguyen
- Section of Medical and Geographical Infectiology, Institute of Medical Microbiology, University Hospital of Münster, Münster, Germany
| | - Miki Matsuo
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), Microbial Genetics, University of Tübingen, Tübingen, Germany
| | - Silke Niemann
- Section of Medical and Geographical Infectiology, Institute of Medical Microbiology, University Hospital of Münster, Münster, Germany
| | - Mathias Herrmann
- Section of Medical and Geographical Infectiology, Institute of Medical Microbiology, University Hospital of Münster, Münster, Germany
| | - Friedrich Götz
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), Microbial Genetics, University of Tübingen, Tübingen, Germany
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36
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Sitte E, Senge MO. The Red Color of Life Transformed - Synthetic Advances and Emerging Applications of Protoporphyrin IX in Chemical Biology. European J Org Chem 2020; 2020:3171-3191. [PMID: 32612451 PMCID: PMC7319466 DOI: 10.1002/ejoc.202000074] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Indexed: 01/10/2023]
Abstract
Protoporphyrin IX (PPIX) is the porphyrin scaffold of heme b, a ubiquitous prosthetic group of proteins responsible for oxygen binding (hemoglobin, myoglobin), electron transfer (cytochrome c) and catalysis (cytochrome P450, catalases, peroxidases). PPIX and its metallated derivatives frequently find application as therapeutic agents, imaging tools, catalysts, sensors and in light harvesting. The vast toolkit of accessible porphyrin functionalization reactions enables easy synthetic modification of PPIX to meet the requirements for its multiple uses. In the past few years, particular interest has arisen in exploiting the interaction of PPIX and its synthetic derivatives with biomolecules such as DNA and heme-binding proteins to evolve molecular devices with new functions as well as to uncover potential therapeutic toeholds. This review strives to shine a light on the most recent developments in the synthetic chemistry of PPIX and its uses in selected fields of chemical biology.
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Affiliation(s)
- Elisabeth Sitte
- School of ChemistryTrinity College DublinThe University of DublinTrinity Biomedical Sciences Institute152‐160 Pearse Street2DublinIreland
| | - Mathias O. Senge
- School of ChemistryTrinity College DublinThe University of DublinTrinity Biomedical Sciences Institute152‐160 Pearse Street2DublinIreland
- Institute for Advanced Study (TUM‐IAS)Technische Universität MünchenLichtenberg‐Str. 2a85748GarchingGermany
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Zhou C, Fey PD. The acid response network of Staphylococcus aureus. Curr Opin Microbiol 2020; 55:67-73. [PMID: 32361405 PMCID: PMC7311314 DOI: 10.1016/j.mib.2020.03.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Revised: 03/17/2020] [Accepted: 03/18/2020] [Indexed: 12/12/2022]
Abstract
Staphylococcus aureus colonizes or causes infection in a multitude of niches within a mammalian host. Many of these niches are acidic, yet specific pH resistance mechanisms that facilitate survival have not been thoroughly investigated. This review discusses recent studies documenting known acid resistance mechanisms in S. aureus and other staphylococcal species. However, studies that clearly define the regulation of the acid resistance regulon and potential interactions with weak organic acids in specific niches of the host including the skin and gut are yet to be defined.
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Affiliation(s)
- Chunyi Zhou
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States
| | - Paul D Fey
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States.
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Rudra P, Boyd JM. Metabolic control of virulence factor production in Staphylococcus aureus. Curr Opin Microbiol 2020; 55:81-87. [PMID: 32388086 DOI: 10.1016/j.mib.2020.03.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 03/09/2020] [Accepted: 03/10/2020] [Indexed: 12/27/2022]
Abstract
As investigators decipher the underlining mechanisms of Staphylococcus aureus pathogenesis, it is becoming apparent that perturbations in central metabolism alter virulence factor production and infection outcomes. It is also evident that S. aureus has the ability to metabolically adapt to improve colonization and overcome challenges imparted by the immune system. Altered metabolite pools modify virulence factor production suggesting that proper functioning of a core metabolic network is necessary for successful niche colonization and pathogenesis. Herein we discuss four examples of transcriptional regulators that monitor metabolic status. These regulatory systems sense perturbations in the metabolic network and respond by altering the transcription of genes utilized for central metabolism, energy generation and pathogenesis.
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Affiliation(s)
- Paulami Rudra
- Department of Biochemistry and Microbiology, Rutgers, the State University of New Jersey, New Brunswick, NJ 08901, USA
| | - Jeffrey M Boyd
- Department of Biochemistry and Microbiology, Rutgers, the State University of New Jersey, New Brunswick, NJ 08901, USA.
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Genetic Regulation of Metal Ion Homeostasis in Staphylococcus aureus. Trends Microbiol 2020; 28:821-831. [PMID: 32381454 DOI: 10.1016/j.tim.2020.04.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 04/01/2020] [Accepted: 04/02/2020] [Indexed: 12/16/2022]
Abstract
The acquisition of metal ions and the proper maturation of holo-metalloproteins are essential processes for all organisms. However, metal ion homeostasis is a double-edged sword. A cytosolic accumulation of metal ions can lead to mismetallation of proteins and cell death. Therefore, maintenance of proper concentrations of intracellular metals is essential for cell fitness and pathogenesis. Staphylococcus aureus, like all bacterial pathogens, uses transcriptional metalloregulatory proteins to aid in the detection and the genetic response to changes in metal ion concentrations. Herein, we review the mechanisms by which S. aureus senses and responds to alterations in the levels of cellular zinc, iron, heme, and copper. The interplay between metal ion sensing and metal-dependent expression of virulence factors is also discussed.
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Schurig-Briccio LA, Parraga Solorzano PK, Lencina AM, Radin JN, Chen GY, Sauer JD, Kehl-Fie TE, Gennis RB. Role of respiratory NADH oxidation in the regulation of Staphylococcus aureus virulence. EMBO Rep 2020; 21:e45832. [PMID: 32202364 DOI: 10.15252/embr.201845832] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 02/21/2020] [Accepted: 02/26/2020] [Indexed: 01/28/2023] Open
Abstract
The success of Staphylococcus aureus as a pathogen is due to its capability of fine-tuning its cellular physiology to meet the challenges presented by diverse environments, which allows it to colonize multiple niches within a single vertebrate host. Elucidating the roles of energy-yielding metabolic pathways could uncover attractive therapeutic strategies and targets. In this work, we seek to determine the effects of disabling NADH-dependent aerobic respiration on the physiology of S. aureus. Differing from many pathogens, S. aureus has two type-2 respiratory NADH dehydrogenases (NDH-2s) but lacks the respiratory ion-pumping NDHs. Here, we show that the NDH-2s, individually or together, are not essential either for respiration or growth. Nevertheless, their absence eliminates biofilm formation, production of α-toxin, and reduces the ability to colonize specific organs in a mouse model of systemic infection. Moreover, we demonstrate that the reason behind these phenotypes is the alteration of the fatty acid metabolism. Importantly, the SaeRS two-component system, which responds to fatty acids regulation, is responsible for the link between NADH-dependent respiration and virulence in S. aureus.
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Affiliation(s)
| | - Paola K Parraga Solorzano
- Department of Microbiology, University of Illinois, Urbana, IL, USA.,Departamento de Ciencias de la Vida, Universidad de las Fuerzas Armada ESPE, Sangolquí, Ecuador
| | - Andrea M Lencina
- Department of Biochemistry, University of Illinois, Urbana, IL, USA
| | - Jana N Radin
- Department of Microbiology, University of Illinois, Urbana, IL, USA
| | - Grischa Y Chen
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, USA
| | - John-Demian Sauer
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, USA
| | - Thomas E Kehl-Fie
- Department of Microbiology, University of Illinois, Urbana, IL, USA.,Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, IL, USA
| | - Robert B Gennis
- Department of Biochemistry, University of Illinois, Urbana, IL, USA
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Jiang W, Oikonomou P, Tavazoie S. Comprehensive Genome-wide Perturbations via CRISPR Adaptation Reveal Complex Genetics of Antibiotic Sensitivity. Cell 2020; 180:1002-1017.e31. [PMID: 32109417 PMCID: PMC7169367 DOI: 10.1016/j.cell.2020.02.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 12/04/2019] [Accepted: 02/04/2020] [Indexed: 12/19/2022]
Abstract
Genome-wide CRISPR screens enable systematic interrogation of gene function. However, guide RNA libraries are costly to synthesize, and their limited diversity compromises the sensitivity of CRISPR screens. Using the Streptococcus pyogenes CRISPR-Cas adaptation machinery, we developed CRISPR adaptation-mediated library manufacturing (CALM), which turns bacterial cells into "factories" for generating hundreds of thousands of crRNAs covering 95% of all targetable genomic sites. With an average gene targeted by more than 100 distinct crRNAs, these highly comprehensive CRISPRi libraries produced varying degrees of transcriptional repression critical for uncovering novel antibiotic resistance determinants. Furthermore, by iterating CRISPR adaptation, we rapidly generated dual-crRNA libraries representing more than 100,000 dual-gene perturbations. The polarized nature of spacer adaptation revealed the historical contingency in the stepwise acquisition of genetic perturbations leading to increasing antibiotic resistance. CALM circumvents the expense, labor, and time required for synthesis and cloning of gRNAs, allowing generation of CRISPRi libraries in wild-type bacteria refractory to routine genetic manipulation.
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Affiliation(s)
- Wenyan Jiang
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA; Department of Systems Biology, Columbia University, New York, NY 10032, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Panos Oikonomou
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA; Department of Systems Biology, Columbia University, New York, NY 10032, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Saeed Tavazoie
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA; Department of Systems Biology, Columbia University, New York, NY 10032, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA.
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mSphere of Influence: a Controlled Burn—Pathogen Manipulation of the Dynamic Chemistry That Results from Inflammation. mSphere 2020; 5:5/1/e00110-20. [PMID: 32102940 PMCID: PMC7045386 DOI: 10.1128/msphere.00110-20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Neal Hammer works in the field of bacterial pathogenesis, metabolism, and antibiotic resistance. In this mSphere of Influence article, he reflects on how “Gut inflammation provides a respiratory electron acceptor for Salmonella” by Winter and colleagues (S. E. Winter, P. Thiennimitr, M. G. Winter, B. P. Butler, et al., Nature 467:426–429, 2010, https://doi.org/10.1038/nature09415) made an impact on him by demonstrating that Salmonella enterica serotype Typhimurium metabolism is uniquely suited to exploit the chemical by-products that result from the host’s inflammatory response. Neal Hammer works in the field of bacterial pathogenesis, metabolism, and antibiotic resistance. In this mSphere of Influence article, he reflects on how “Gut inflammation provides a respiratory electron acceptor for Salmonella” by Winter and colleagues (S. E. Winter, P. Thiennimitr, M. G. Winter, B. P. Butler, et al., Nature 467:426–429, 2010, https://doi.org/10.1038/nature09415) made an impact on him by demonstrating that Salmonella enterica serotype Typhimurium metabolism is uniquely suited to exploit the chemical by-products that result from the host’s inflammatory response.
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The Staphylococcus aureus Cystine Transporters TcyABC and TcyP Facilitate Nutrient Sulfur Acquisition during Infection. Infect Immun 2020; 88:IAI.00690-19. [PMID: 31843961 DOI: 10.1128/iai.00690-19] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Accepted: 12/06/2019] [Indexed: 12/21/2022] Open
Abstract
Staphylococcus aureus is a significant human pathogen due to its capacity to cause a multitude of diseases. As such, S. aureus efficiently pillages vital nutrients from the host; however, the molecular mechanisms that support sulfur acquisition during infection have not been established. One of the most abundant extracellular sulfur-containing metabolites within the host is cysteine, which acts as the major redox buffer in the blood by transitioning between reduced and oxidized (cystine) forms. We therefore hypothesized that S. aureus acquires host-derived cysteine and cystine as sources of nutrient sulfur during systemic infection. To test this hypothesis, we used the toxic cystine analogue selenocystine to initially characterize S. aureus homologues of the Bacillus subtilis cystine transporters TcyABC and TcyP. We found that genetic inactivation of both TcyA and TcyP induced selenocystine resistance. The double mutant also failed to proliferate in medium supplemented with cystine, cysteine, or N-acetyl cysteine as the sole sulfur source. However, only TcyABC was necessary for proliferation in defined medium containing homocystine as the sulfur source. Using a murine model of systemic infection, we observed tcyP-dependent competitive defects in the liver and heart, indicating that this sulfur acquisition strategy supports proliferation of S. aureus in these organs. Phylogenetic analyses identified TcyP homologues in many pathogenic species, implying that this sulfur procurement strategy is conserved. In total, this study is the first to experimentally validate sulfur acquisition systems in S. aureus and establish their importance during pathogenesis.
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Goojani HG, Konings J, Hakvoort H, Hong S, Gennis RB, Sakamoto J, Lill H, Bald D. The carboxy-terminal insert in the Q-loop is needed for functionality of Escherichia coli cytochrome bd-I. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1861:148175. [PMID: 32061652 DOI: 10.1016/j.bbabio.2020.148175] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 01/24/2020] [Accepted: 02/10/2020] [Indexed: 12/27/2022]
Abstract
Cytochrome bd, a component of the prokaryotic respiratory chain, is important under physiological stress and during pathogenicity. Electrons from quinol substrates are passed on via heme groups in the CydA subunit and used to reduce molecular oxygen. Close to the quinol binding site, CydA displays a periplasmic hydrophilic loop called Q-loop that is essential for quinol oxidation. In the carboxy-terminal part of this loop, CydA from Escherichia coli and other proteobacteria harbors an insert of ~60 residues with unknown function. In the current work, we demonstrate that growth of the multiple-deletion strain E. coli MB43∆cydA (∆cydA∆cydB∆appB∆cyoB∆nuoB) can be enhanced by transformation with E. coli cytochrome bd-I and we utilize this system for assessment of Q-loop mutants. Deletion of the cytochrome bd-I Q-loop insert abolished MB43∆cydA growth recovery. Swapping the cytochrome bd-I Q-loop for the Q-loop from Geobacillus thermodenitrificans or Mycobacterium tuberculosis CydA, which lack the insert, did not enhance the growth of MB43∆cydA, whereas swapping for the Q-loop from E. coli cytochrome bd-II recovered growth. Alanine scanning experiments identified the cytochrome bd-I Q-loop insert regions Ile318-Met322, Gln338-Asp342, Tyr353-Leu357, and Thr368-Ile372 as important for enzyme functionality. Those mutants that completely failed to recover growth of MB43∆cydA also lacked oxygen consumption activity and heme absorption peaks. Moreover, we were not able to isolate cytochrome bd-I from these inactive mutants. The results indicate that the cytochrome bd Q-loop exhibits low plasticity and that the Q-loop insert in E. coli is needed for complete, stable, assembly of cytochrome bd-I.
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Affiliation(s)
- Hojjat Ghasemi Goojani
- Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, the Netherlands
| | - Julia Konings
- Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, the Netherlands
| | - Henk Hakvoort
- Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, the Netherlands
| | - Sangjin Hong
- Department of Biochemistry, University of Illinois, 600 S. Mathews Avenue, Urbana, IL 61801, United States
| | - Robert B Gennis
- Department of Biochemistry, University of Illinois, 600 S. Mathews Avenue, Urbana, IL 61801, United States
| | - Junshi Sakamoto
- Department of Bioscience and Bioinformatics, Kyushu Institute of Technology, Kawazu 680-4, Iizuka, Fukuoka-ken 820-8502, Japan
| | - Holger Lill
- Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, the Netherlands
| | - Dirk Bald
- Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, the Netherlands.
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Liu CC, Lin MH. Involvement of Heme in Colony Spreading of Staphylococcus aureus. Front Microbiol 2020; 11:170. [PMID: 32117177 PMCID: PMC7026375 DOI: 10.3389/fmicb.2020.00170] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 01/24/2020] [Indexed: 11/13/2022] Open
Abstract
Staphylococcus aureus spreads rapidly on the surface of soft agar medium. The spreading depends on the synthesis of biosurfactants, i.e., phenol soluble modulins (PSMs), which facilitate colony spreading of S. aureus. Our earlier study demonstrated that water accumulates in a colony is important to modulate colony spreading of S. aureus. The current study screened a transposon-based mutant library of S. aureus HG001 and obtained four non-spreading mutants with mutations in hemY and ctaA, which are involved in heme synthesis. The spreading ability of these mutants was restored when the mutants are transformed with a plasmid encoding hemY or ctaA, respectively. HemY mutants, which do not synthesize heme B, were able to spread on agar medium supplemented with hemin, a heme B derivative. By contrast, hemin supplementation did not rescue the spreading of the ctaA mutant, which lacks heme B and heme A, indicating that heme A is also critical for colony spreading. Moreover, mutations in hemY and ctaA had little effect on PSMs production but affect ATP production and water accumulation in the colony. In conclusion, this study sheds light on the role of heme synthesis and energy production in the regulation of S. aureus colony spreading, which is important for understanding the movement mechanisms of bacteria lacking a motor apparatus.
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Affiliation(s)
- Chao-Chin Liu
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Mei-Hui Lin
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Department of Laboratory Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan
- *Correspondence: Mei-Hui Lin,
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Ito T, Gallegos R, Matano LM, Butler NL, Hantman N, Kaili M, Coyne MJ, Comstock LE, Malamy MH, Barquera B. Genetic and Biochemical Analysis of Anaerobic Respiration in Bacteroides fragilis and Its Importance In Vivo. mBio 2020; 11:e03238-19. [PMID: 32019804 PMCID: PMC7002350 DOI: 10.1128/mbio.03238-19] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 12/13/2019] [Indexed: 12/14/2022] Open
Abstract
In bacteria, the respiratory pathways that drive molecular transport and ATP synthesis include a variety of enzyme complexes that utilize different electron donors and acceptors. This property allows them to vary the efficiency of energy conservation and to generate different types of electrochemical gradients (H+ or Na+). We know little about the respiratory pathways in Bacteroides species, which are abundant in the human gut, and whether they have a simple or a branched pathway. Here, we combined genetics, enzyme activity measurements, and mammalian gut colonization assays to better understand the first committed step in respiration, the transfer of electrons from NADH to quinone. We found that a model gut Bacteroides species, Bacteroides fragilis, has all three types of putative NADH dehydrogenases that typically transfer electrons from the highly reducing molecule NADH to quinone. Analyses of NADH oxidation and quinone reduction in wild-type and deletion mutants showed that two of these enzymes, Na+-pumping NADH:quinone oxidoreductase (NQR) and NADH dehydrogenase II (NDH2), have NADH dehydrogenase activity, whereas H+-pumping NADH:ubiquinone oxidoreductase (NUO) does not. Under anaerobic conditions, NQR contributes more than 65% of the NADH:quinone oxidoreductase activity. When grown in rich medium, none of the single deletion mutants had a significant growth defect; however, the double Δnqr Δndh2 mutant, which lacked almost all NADH:quinone oxidoreductase activity, had a significantly increased doubling time. Despite unaltered in vitro growth, the single nqr deletion mutant was unable to competitively colonize the gnotobiotic mouse gut, confirming the importance of NQR to respiration in B. fragilis and the overall importance of respiration to this abundant gut symbiont.IMPORTANCEBacteroides species are abundant in the human intestine and provide numerous beneficial properties to their hosts. The ability of Bacteroides species to convert host and dietary glycans and polysaccharides to energy is paramount to their success in the human gut. We know a great deal about the molecules that these bacteria extract from the human gut but much less about how they convert those molecules into energy. Here, we show that B. fragilis has a complex respiratory pathway with two different enzymes that transfer electrons from NADH to quinone and a third enzyme complex that may use an electron donor other than NADH. Although fermentation has generally been believed to be the main mechanism of energy generation in Bacteroides, we found that a mutant lacking one of the NADH:quinone oxidoreductases was unable to compete with the wild type in the mammalian gut, revealing the importance of respiration to these abundant gut symbionts.
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Affiliation(s)
- Takeshi Ito
- Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy, New York, USA
| | - Rene Gallegos
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Leigh M Matano
- Division of Infectious Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Nicole L Butler
- Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy, New York, USA
- Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, New York, USA
| | - Noam Hantman
- Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy, New York, USA
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, New York, USA
| | - Matthew Kaili
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Michael J Coyne
- Division of Infectious Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Laurie E Comstock
- Division of Infectious Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Michael H Malamy
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Blanca Barquera
- Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy, New York, USA
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, New York, USA
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Mascolo L, Bald D. Cytochrome bd in Mycobacterium tuberculosis: A respiratory chain protein involved in the defense against antibacterials. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2019; 152:55-63. [PMID: 31738981 DOI: 10.1016/j.pbiomolbio.2019.11.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 11/12/2019] [Indexed: 12/27/2022]
Abstract
The branched respiratory chain of Mycobacterium tuberculosis has attracted attention as a highly promising target for next-generation antibacterials. This system includes two terminal oxidases of which the exclusively bacterial cytochrome bd represents the less energy-efficient one. Albeit dispensable for growth under standard laboratory conditions, cytochrome bd is important during environmental stress. In this review, we discuss the role of cytochrome bd during infection of the mammalian host and in the defense against antibacterials. Deeper insight into the biochemistry of mycobacterial cytochrome bd is needed to understand the physiological role of this bacteria-specific defense factor. Conversely, cytochrome bd may be utilized to gain information on mycobacterial physiology in vitro and during host infection. Knowledge-based manipulation of cytochrome bd function may assist in designing the next-generation tuberculosis combination chemotherapy.
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Affiliation(s)
- Ludovica Mascolo
- Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands
| | - Dirk Bald
- Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands.
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Schleimer N, Kaspar U, Ballhausen B, Fotiadis SA, Streu JM, Kriegeskorte A, Proctor RA, Becker K. Adaption of an Episomal Antisense Silencing Approach for Investigation of the Phenotype Switch of Staphylococcus aureus Small-Colony Variants. Front Microbiol 2019; 10:2044. [PMID: 31551979 PMCID: PMC6738336 DOI: 10.3389/fmicb.2019.02044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 08/20/2019] [Indexed: 11/13/2022] Open
Abstract
Staphylococcus aureus small-colony variants (SCVs) are associated with chronic, persistent, and relapsing courses of infection and are characterized by slow growth combined with other phenotypic and molecular traits. Although certain mechanisms have been described, the genetic basis of clinical SCVs remains often unknown. Hence, we adapted an episomal tool for rapid identification and investigation of putative SCV phenotype-associated genes via antisense gene silencing based on previously described Tnl0-encoded tet-regulatory elements. Targeting the SCV phenotype-inducing enoyl-acyl-carrier-protein reductase gene (fabI), plasmid pSN1-AS‘fabI’ was generated leading to antisense silencing, which was proven by pronounced growth retardation in liquid cultures, phenotype switch on solid medium, and 200-fold increase of antisense ‘fabI’ expression. A crucial role of TetR repression in effective regulation of the system was demonstrated. Based on the use of anhydrotetracycline as effector, an easy-to-handle one-plasmid setup was set that may be applicable to different S. aureus backgrounds and cell culture studies. However, selection of the appropriate antisense fragment of the target gene remains a critical factor for effectiveness of silencing. This inducible gene expression system may help to identify SCV phenotype-inducing genes, which is prerequisite for the development of new antistaphylococcal agents and future alternative strategies to improve treatment of therapy-refractory SCV-related infections by iatrogenically induced phenotypic switch. Moreover, it can be used as controllable phenotype switcher to examine important aspects of SCV biology in cell culture as well as in vivo.
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Affiliation(s)
- Nina Schleimer
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
| | - Ursula Kaspar
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
| | - Britta Ballhausen
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
| | - Sarah A Fotiadis
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
| | - Jessica M Streu
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
| | - André Kriegeskorte
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
| | - Richard A Proctor
- Departments of Medical Microbiology/Immunology and Medicine, School of Medicine and Public Health, University of Wisconsin, Madison, WI, United States
| | - Karsten Becker
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
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The ClpCP Complex Modulates Respiratory Metabolism in Staphylococcus aureus and Is Regulated in a SrrAB-Dependent Manner. J Bacteriol 2019; 201:JB.00188-19. [PMID: 31109995 DOI: 10.1128/jb.00188-19] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 05/17/2019] [Indexed: 01/13/2023] Open
Abstract
The staphylococcal respiratory regulator (SrrAB) modulates energy metabolism in Staphylococcus aureus Studies have suggested that regulated protein catabolism facilitates energy homeostasis. Regulated proteolysis in S. aureus is achieved through protein complexes composed of a peptidase (ClpQ or ClpP) in association with an AAA+ family ATPase (typically, ClpC or ClpX). In the present report, we tested the hypothesis that SrrAB regulates a Clp complex to facilitate energy homeostasis in S. aureus Strains deficient in one or more Clp complexes were attenuated for growth in the presence of puromycin, which causes enrichment of misfolded proteins. A ΔsrrAB strain had increased sensitivity to puromycin. Epistasis experiments suggested that the puromycin sensitivity phenotype of the ΔsrrAB strain was a result of decreased ClpC activity. Consistent with this, transcriptional activity of clpC was decreased in the ΔsrrAB mutant, and overexpression of clpC suppressed the puromycin sensitivity of the ΔsrrAB strain. We also found that ClpC positively influenced respiration and that it did so upon association with ClpP. In contrast, ClpC limited fermentative growth, while ClpP was required for optimal fermentative growth. Metabolomics studies demonstrated that intracellular metabolic profiles of the ΔclpC and ΔsrrAB mutants were distinct from those of the wild-type strain, supporting the notion that both ClpC and SrrAB affect central metabolism. We propose a model wherein SrrAB regulates energy homeostasis, in part, via modulation of regulated proteolysis.IMPORTANCE Oxygen is used as a substrate to derive energy by the bacterial pathogen Staphylococcus aureus during infection; however, S. aureus can also grow fermentatively in the absence of oxygen. To successfully cause infection, S. aureus must tailor its metabolism to take advantage of respiratory activity. Different proteins are required for growth in the presence or absence of oxygen; therefore, when cells transition between these conditions, several proteins would be expected to become unnecessary. In this report, we show that regulated proteolysis is used to modulate energy metabolism in S. aureus We report that the ClpCP protein complex is involved in specifically modulating aerobic respiratory growth but is dispensable for fermentative growth.
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Choby JE, Skaar EP. Staphylococcus aureus Coproporphyrinogen III Oxidase Is Required for Aerobic and Anaerobic Heme Synthesis. mSphere 2019; 4:e00235-19. [PMID: 31292227 PMCID: PMC6620371 DOI: 10.1128/msphere.00235-19] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 06/26/2019] [Indexed: 11/20/2022] Open
Abstract
The virulence of the human pathogen Staphylococcus aureus is supported by many heme-dependent proteins, including key enzymes of cellular respiration. Therefore, synthesis of heme is a critical component of staphylococcal physiology. S. aureus generates heme via the coproporphyrin-dependent pathway, conserved across members of the Firmicutes and Actinobacteria In this work, we genetically investigate the oxidation of coproporphyrinogen to coproporphyrin in this heme synthesis pathway. The coproporphyrinogen III oxidase CgoX has previously been identified as the oxygen-dependent enzyme responsible for this conversion under aerobic conditions. However, because S. aureus uses heme during anaerobic nitrate respiration, we hypothesized that coproporphyrin production is able to proceed in the absence of oxygen. Therefore, we tested the contribution to anaerobic heme synthesis of CgoX and two other proteins previously identified as potential oxygen-independent coproporphyrinogen dehydrogenases, NWMN_1486 and NWMN_1636. We have found that CgoX alone is responsible for aerobic and anaerobic coproporphyrin synthesis from coproporphyrinogen and is required for aerobic and anaerobic heme-dependent growth. This work provides an explanation for how S. aureus heme synthesis proceeds under both aerobic and anaerobic conditions.IMPORTANCE Heme is a critical molecule required for aerobic and anaerobic respiration by organisms across kingdoms. The human pathogen Staphylococcus aureus has served as a model organism for the study of heme synthesis and heme-dependent physiology and, like many species of the phyla Firmicutes and Actinobacteria, generates heme through a coproporphyrin intermediate. A critical step in terminal heme synthesis is the production of coproporphyrin by the CgoX enzyme, which was presumed to be oxygen dependent. However, S. aureus also requires heme during anaerobic growth; therefore, the synthesis of coproporphyrin by an oxygen-independent mechanism is required. Here, we identify CgoX as the enzyme performing the oxygen-dependent and -independent synthesis of coproporphyrin from coproporphyrinogen, resolving a key outstanding question in the coproporphyrin-dependent heme synthesis pathway.
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Affiliation(s)
- Jacob E Choby
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Graduate Program in Microbiology and Immunology, Vanderbilt University, Nashville, Tennessee, USA
| | - Eric P Skaar
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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