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Manenica M, Bertoša B. Molecular basis of protein-DNA interactions between Halalkalibacterium halodurans MntR and its DNA operator sequence. Int J Biol Macromol 2025; 311:142937. [PMID: 40216114 DOI: 10.1016/j.ijbiomac.2025.142937] [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] [Received: 01/14/2025] [Revised: 03/25/2025] [Accepted: 04/06/2025] [Indexed: 05/03/2025]
Abstract
Transition metals such as iron, zinc and manganese are essential for bacterial survival. A pivotal role in regulation of manganese homeostasis in bacterium Halalkalibacterium halodurans has MntR protein (HhMntR). In this work, molecular dynamics simulations of holoprotein (with Mn2+) and apoprotein (without Mn2+) HhMntR in complex with DNA mntA operator were conducted and enabled understanding of interaction between HhMntR and DNA on molecular level. Molecular mechanism through which affinity of HhMntR towards DNA is increased upon Mn2+ binding was revealed. Holoprotein binds DNA through stable and consistent noncovalent interactions, while apoprotein shows highly dynamic behavior, attaching to and detaching from the DNA backbone and inner grooves on a nanosecond time scale. The same observations are seen even during the simulations that started with protein and DNA separated from the complex. Additionally, key amino acids involved in the formation of the HhMntR-DNA complex were identified, leading to the proposal of a molecular framework that allows HhMntR to perform its biological function as a transcription factor. Overall, observed behaviors promote the lateral movement of HhMntR along the DNA sequence, enabling the protein to remain close to the DNA while it seeks out specific base pairs for strong binding upon activation by Mn2+.
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Affiliation(s)
- Martina Manenica
- Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, HR-10000 Zagreb, Croatia
| | - Branimir Bertoša
- Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, HR-10000 Zagreb, Croatia.
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2
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Shi H, Fu Y, Kodyte V, Andreas A, Sachla AJ, Miller K, Shrestha R, Helmann JD, Glasfeld A, Ahuja S. Structural basis for transcription activation through cooperative recruitment of MntR. Nat Commun 2025; 16:2204. [PMID: 40044701 PMCID: PMC11882963 DOI: 10.1038/s41467-025-57412-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2024] [Accepted: 02/12/2025] [Indexed: 03/09/2025] Open
Abstract
Bacillus subtilis MntR is a dual regulatory protein that responds to heightened Mn2+ availability in the cell by both repressing the expression of uptake transporters and activating the expression of efflux proteins. Recent work indicates that, in its role as an activator, MntR binds several sites upstream of the genes encoding Mn2+ exporters, leading to a cooperative response to manganese. Here, we use cryo-EM to explore the molecular basis of gene activation by MntR and report a structure of four MntR dimers bound to four 18-base pair sites across an 84-base pair regulatory region of the mneP promoter. Our structures, along with solution studies including mass photometry and in vivo transcription assays, reveal that MntR dimers employ polar and non-polar contacts to bind cooperatively to an array of low-affinity DNA-binding sites. These results reveal the molecular basis for cooperativity in the activation of manganese efflux.
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Affiliation(s)
- Haoyuan Shi
- Department of Chemistry, Reed College, Portland, Oregon, USA
| | - Yu Fu
- Department of Chemistry, Reed College, Portland, Oregon, USA
| | - Vilmante Kodyte
- Department of Chemistry, Reed College, Portland, Oregon, USA
| | - Amelie Andreas
- Department of Chemistry, Reed College, Portland, Oregon, USA
| | - Ankita J Sachla
- Department of Microbiology, Cornell University, Ithaca, NY, USA
| | | | | | - John D Helmann
- Department of Microbiology, Cornell University, Ithaca, NY, USA
| | - Arthur Glasfeld
- Department of Chemistry, Reed College, Portland, Oregon, USA
| | - Shivani Ahuja
- Department of Chemistry, Reed College, Portland, Oregon, USA.
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3
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Prabhu C, Satyaprasad AU, Deekshit VK. Understanding Bacterial Resistance to Heavy Metals and Nanoparticles: Mechanisms, Implications, and Challenges. J Basic Microbiol 2025; 65:e2400596. [PMID: 39696916 DOI: 10.1002/jobm.202400596] [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: 09/10/2024] [Revised: 10/30/2024] [Accepted: 12/02/2024] [Indexed: 12/20/2024]
Abstract
Antimicrobial resistance is a global health problem as it contributes to high mortality rates in several infectious diseases. To address this issue, engineered nanoparticles/nano-formulations of antibiotics have emerged as a promising strategy. Nanoparticles are typically defined as materials with dimensions up to 100 nm and are made of different materials such as inorganic particles, lipids, polymers, etc. They are widely dispersed in the environment through various consumer products, and their clinical applications are diverse, ranging from contrast agents in imaging to carriers for gene and drug delivery. Nanoparticles can also act as antimicrobial agents either on their own or in combination with traditional antibiotics to produce synergistic effects, earning them the label of "next-generation therapeutics." They have also shown great effectiveness against multidrug-resistant pathogens responsible for nosocomial infections. However, overexposure or prolonged exposure to sublethal doses of nanoparticles can promote the development of resistance in human pathogens. The resistance can arise from various factors such as genetic mutation, horizontal gene transfer, production of reactive oxygen species, changes in the outer membrane of bacteria, efflux-induced resistance, cross-resistance from intrinsic antibiotic resistance determinants, plasmid-mediated resistance, and many more. Continuous exposure to nanoparticles can also transform an antibiotic-susceptible bacterial pathogen into multidrug resistance. Considering all these, the current review focuses on the mode of action of different heavy metals and nanoparticles and possible mechanisms through which bacteria attain resistance towards these heavy metals and nanoparticles.
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Affiliation(s)
- Chaitra Prabhu
- Department of Infectious Diseases and Microbial Genomics, NITTE (Deemed to be University), NITTE University Centre for Science Education and Research, Paneer Campus, Deralakatte, Mangaluru, India
| | - Akshath Uchangi Satyaprasad
- Department of Bio and Nano Technology, NITTE (Deemed to be University), NITTE University Centre for Science Education and Research, Paneer Campus, Deralakatte, Mangaluru, India
| | - Vijaya Kumar Deekshit
- Department of Infectious Diseases and Microbial Genomics, NITTE (Deemed to be University), NITTE University Centre for Science Education and Research, Paneer Campus, Deralakatte, Mangaluru, India
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4
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Prakash A, Kalita A, Bhardwaj K, Mishra RK, Ghose D, Kaur G, Verma N, Pani B, Nudler E, Dutta D. Rho and riboswitch-dependent regulations of mntP gene expression evade manganese and membrane toxicities. J Biol Chem 2024; 300:107967. [PMID: 39510182 DOI: 10.1016/j.jbc.2024.107967] [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: 08/29/2024] [Revised: 10/09/2024] [Accepted: 10/27/2024] [Indexed: 11/15/2024] Open
Abstract
The trace metal ion manganese (Mn) in excess is toxic. Therefore, a small subset of factors tightly maintains its cellular level, among which an efflux protein MntP is the champion. Multiple transcriptional regulators and a manganese-dependent translational riboswitch regulate the MntP expression in Escherichia coli. As riboswitches are untranslated RNAs, they are often associated with the Rho-dependent transcription termination in bacteria. Here, performing in vitro transcription and in vivo reporter assays, we demonstrate that Rho efficiently terminates transcription at the mntP riboswitch region. Excess manganese activates the riboswitch, restoring the coupling between transcription and translation to evade Rho-dependent transcription termination partially. RT-PCR and Western blot experiments revealed that the deletion of the riboswitch abolishes Rho-dependent termination and thereby overexpresses MntP. Interestingly, deletion of the riboswitch also renders bacteria sensitive to manganese. This manganese sensitivity is linked with the overexpression of MntP. Further spot assays, confocal microscopy, and flow cytometry experiments revealed that the high level of MntP expression was responsible for slow growth, cell filamentation, and reactive oxygen species (ROS) production. We posit that manganese-dependent transcriptional activation of mntP in the absence of Rho-dependent termination leads to excessive MntP expression, a membrane protein, causing membrane protein toxicity. Thus, we show a regulatory role of Rho-dependent termination, which prevents membrane protein toxicity by limiting MntP expression.
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Affiliation(s)
- Anand Prakash
- Department of Molecular Biochemistry and Microbiology, CSIR Institute of Microbial Technology, Chandigarh, India
| | - Arunima Kalita
- Department of Molecular Biochemistry and Microbiology, CSIR Institute of Microbial Technology, Chandigarh, India
| | - Kanika Bhardwaj
- Department of Molecular Biochemistry and Microbiology, CSIR Institute of Microbial Technology, Chandigarh, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh, India
| | - Rajesh Kumar Mishra
- Department of Molecular Biochemistry and Microbiology, CSIR Institute of Microbial Technology, Chandigarh, India
| | - Debarghya Ghose
- Department of Molecular Biochemistry and Microbiology, CSIR Institute of Microbial Technology, Chandigarh, India
| | - Gursharan Kaur
- Department of Molecular Biochemistry and Microbiology, CSIR Institute of Microbial Technology, Chandigarh, India
| | - Neha Verma
- Department of Molecular Biochemistry and Microbiology, CSIR Institute of Microbial Technology, Chandigarh, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh, India
| | - Bibhusita Pani
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, New York, USA
| | - Evgeny Nudler
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, New York, USA; Howard Hughes Medical Institute, NYU Langone Health, New York, New York, USA
| | - Dipak Dutta
- Department of Molecular Biochemistry and Microbiology, CSIR Institute of Microbial Technology, Chandigarh, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh, India.
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5
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Mota C, Webster M, Saidi M, Kapp U, Zubieta C, Giachin G, Manso JA, de Sanctis D. Metal ion activation and DNA recognition by the Deinococcus radiodurans manganese sensor DR2539. FEBS J 2024; 291:3384-3402. [PMID: 38652591 DOI: 10.1111/febs.17140] [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: 02/15/2024] [Revised: 03/14/2024] [Accepted: 04/10/2024] [Indexed: 04/25/2024]
Abstract
The accumulation of manganese ions is crucial for scavenging reactive oxygen species and protecting the proteome of Deinococcus radiodurans (Dr). However, metal homeostasis still needs to be tightly regulated to avoid toxicity. DR2539, a dimeric transcription regulator, plays a key role in Dr manganese homeostasis. Despite comprising three well-conserved domains - a DNA-binding domain, a dimerisation domain, and an ancillary domain - the mechanisms underlying both, metal ion activation and DNA recognition remain elusive. In this study, we present biophysical analyses and the structure of the dimerisation and DNA-binding domains of DR2539 in its holo-form and in complex with the 21 base pair pseudo-palindromic repeat of the dr1709 promoter region, shedding light on these activation and recognition mechanisms. The dimer presents eight manganese binding sites that induce structural conformations essential for DNA binding. The analysis of the protein-DNA interfaces elucidates the significance of Tyr59 and helix α3 sequence in the interaction with the DNA. Finally, the structure in solution as determined by small-angle X-ray scattering experiments and supported by AlphaFold modeling provides a model illustrating the conformational changes induced upon metal binding.
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Affiliation(s)
- Cristiano Mota
- ESRF - The European Synchrotron, Grenoble, France
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal
- UCIBIO, Applied Molecular Biosciences Unit, Department of Chemistry, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal
| | | | | | - Ulrike Kapp
- ESRF - The European Synchrotron, Grenoble, France
| | | | | | - José Antonio Manso
- IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Portugal
- I3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal
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6
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Shi H, Fu Y, Kodyte V, Andreas A, Sachla AJ, Miller K, Shrestha R, Helmann JD, Glasfeld A, Ahuja S. Structural basis for transcription activation through cooperative recruitment of MntR. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.28.601288. [PMID: 38979284 PMCID: PMC11230367 DOI: 10.1101/2024.06.28.601288] [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
The manganese transport regulator (MntR) from B. subtilis is a dual regulatory protein that responds to heightened Mn 2+ availability in the cell by both repressing the expression of uptake transporters and activating the expression of efflux proteins. Recent work indicates that, in its role as an activator, MntR binds several sites upstream of the genes encoding Mn 2+ exporters, leading to a cooperative response to manganese. Here, we use cryo-EM to explore the molecular basis of gene activation by MntR and report a structure of four MntR dimers bound to four 18-base pair sites across an 84-base pair regulatory region of the mneP promoter. Our structures, along with solution studies including mass photometry and in vivo transcription assays, reveal that MntR dimers employ polar and non-polar contacts to bind cooperatively to an array of low-affinity DNA-binding sites. These results reveal the molecular basis for cooperativity in the activation of manganese efflux.
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7
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Sachla AJ, Soni V, Piñeros M, Luo Y, Im JJ, Rhee KY, Helmann JD. The Bacillus subtilis yqgC-sodA operon protects magnesium-dependent enzymes by supporting manganese efflux. J Bacteriol 2024; 206:e0005224. [PMID: 38819154 PMCID: PMC11332163 DOI: 10.1128/jb.00052-24] [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: 02/13/2024] [Accepted: 05/08/2024] [Indexed: 06/01/2024] Open
Abstract
Microbes encounter a myriad of stresses during their life cycle. Dysregulation of metal ion homeostasis is increasingly recognized as a key factor in host-microbe interactions. Bacterial metal ion homeostasis is tightly regulated by dedicated metalloregulators that control uptake, sequestration, trafficking, and efflux. Here, we demonstrate that deletion of the Bacillus subtilis yqgC-sodA (YS) complex operon, but not deletion of the individual genes, causes hypersensitivity to manganese (Mn). YqgC is an integral membrane protein of unknown function, and SodA is a Mn-dependent superoxide dismutase (MnSOD). The YS strain has reduced expression of two Mn efflux proteins, MneP and MneS, consistent with the observed Mn sensitivity. The YS strain accumulated high levels of Mn, had increased reactive radical species (RRS), and had broad metabolic alterations that can be partially explained by the inhibition of Mg-dependent enzymes. Although the YS operon deletion strain and an efflux-deficient mneP mneS double mutant both accumulate Mn and have similar metabolic perturbations, they also display phenotypic differences. Several mutations that suppressed Mn intoxication of the mneP mneS efflux mutant did not benefit the YS mutant. Further, Mn intoxication in the YS mutant, but not the mneP mneS strain, was alleviated by expression of Mg-dependent, chorismate-utilizing enzymes of the menaquinone, siderophore, and tryptophan (MST) family. Therefore, despite their phenotypic similarities, the Mn sensitivity in the mneP mneS and the YS deletion mutants results from distinct enzymatic vulnerabilities.IMPORTANCEBacteria require multiple trace metal ions for survival. Metal homeostasis relies on the tightly regulated expression of metal uptake, storage, and efflux proteins. Metal intoxication occurs when metal homeostasis is perturbed and often results from enzyme mis-metalation. In Bacillus subtilis, Mn-dependent superoxide dismutase (MnSOD) is the most abundant Mn-containing protein and is important for oxidative stress resistance. Here, we report novel roles for MnSOD and a co-regulated membrane protein, YqgC, in Mn homeostasis. Loss of both MnSOD and YqgC (but not the individual proteins) prevents the efficient expression of Mn efflux proteins and leads to a large-scale perturbation of the metabolome due to inhibition of Mg-dependent enzymes, including key chorismate-utilizing MST (menaquinone, siderophore, and tryptophan) family enzymes.
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Affiliation(s)
- Ankita J. Sachla
- Department of Microbiology, Cornell University, Ithaca, New York, USA
| | - Vijay Soni
- Division of Infectious Diseases, Weill Department of Medicine, Weill Cornell Medicine, New York, New York, USA
| | - Miguel Piñeros
- School of Integrative Plant Sciences, Plant Biology Section, Cornell University, Ithaca, New York, USA
- Robert W. Holley Center for Agriculture and Health, USDA-ARS, Ithaca, New York, USA
| | - Yuanchan Luo
- Department of Microbiology, Cornell University, Ithaca, New York, USA
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Janice J. Im
- Department of Microbiology, Cornell University, Ithaca, New York, USA
| | - Kyu Y. Rhee
- Division of Infectious Diseases, Weill Department of Medicine, Weill Cornell Medicine, New York, New York, USA
| | - John D. Helmann
- Department of Microbiology, Cornell University, Ithaca, New York, USA
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8
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Wang BX, Leshchiner D, Luo L, Tuncel M, Hokamp K, Hinton JCD, Monack DM. High-throughput fitness experiments reveal specific vulnerabilities of human-adapted Salmonella during stress and infection. Nat Genet 2024; 56:1288-1299. [PMID: 38831009 PMCID: PMC11176087 DOI: 10.1038/s41588-024-01779-7] [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: 09/12/2023] [Accepted: 04/25/2024] [Indexed: 06/05/2024]
Abstract
Salmonella enterica is comprised of genetically distinct 'serovars' that together provide an intriguing model for exploring the genetic basis of pathogen evolution. Although the genomes of numerous Salmonella isolates with broad variations in host range and human disease manifestations have been sequenced, the functional links between genetic and phenotypic differences among these serovars remain poorly understood. Here, we conduct high-throughput functional genomics on both generalist (Typhimurium) and human-restricted (Typhi and Paratyphi A) Salmonella at unprecedented scale in the study of this enteric pathogen. Using a comprehensive systems biology approach, we identify gene networks with serovar-specific fitness effects across 25 host-associated stresses encountered at key stages of human infection. By experimentally perturbing these networks, we characterize previously undescribed pseudogenes in human-adapted Salmonella. Overall, this work highlights specific vulnerabilities encoded within human-restricted Salmonella that are linked to the degradation of their genomes, shedding light into the evolution of this enteric pathogen.
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Affiliation(s)
- Benjamin X Wang
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA
| | | | - Lijuan Luo
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Miles Tuncel
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA
| | - Karsten Hokamp
- Department of Genetics, School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland
| | - Jay C D Hinton
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Denise M Monack
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA.
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9
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Willner DL, Paudel S, Halleran AD, Solini GE, Gray V, Saha MS. Transcriptional dynamics during Rhodococcus erythropolis infection with phage WC1. BMC Microbiol 2024; 24:107. [PMID: 38561651 PMCID: PMC10986025 DOI: 10.1186/s12866-024-03241-4] [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: 11/25/2023] [Accepted: 02/27/2024] [Indexed: 04/04/2024] Open
Abstract
BACKGROUND Belonging to the Actinobacteria phylum, members of the Rhodococcus genus thrive in soil, water, and even intracellularly. While most species are non-pathogenic, several cause respiratory disease in animals and, more rarely, in humans. Over 100 phages that infect Rhodococcus species have been isolated but despite their importance for Rhodococcus ecology and biotechnology applications, little is known regarding the molecular genetic interactions between phage and host during infection. To address this need, we report RNA-Seq analysis of a novel Rhodococcus erythopolis phage, WC1, analyzing both the phage and host transcriptome at various stages throughout the infection process. RESULTS By five minutes post-infection WC1 showed upregulation of a CAS-4 family exonuclease, putative immunity repressor, an anti-restriction protein, while the host showed strong upregulation of DNA replication, SOS repair, and ribosomal protein genes. By 30 min post-infection, WC1 DNA synthesis genes were strongly upregulated while the host showed increased expression of transcriptional and translational machinery and downregulation of genes involved in carbon, energy, and lipid metabolism pathways. By 60 min WC1 strongly upregulated structural genes while the host showed a dramatic disruption of metal ion homeostasis. There was significant expression of both host and phage non-coding genes at all time points. While host gene expression declined over the course of infection, our results indicate that phage may exert more selective control, preserving the host's regulatory mechanisms to create an environment conducive for virion production. CONCLUSIONS The Rhodococcus genus is well recognized for its ability to synthesize valuable compounds, particularly steroids, as well as its capacity to degrade a wide range of harmful environmental pollutants. A detailed understanding of these phage-host interactions and gene expression is not only essential for understanding the ecology of this important genus, but will also facilitate development of phage-mediated strategies for bioremediation as well as biocontrol in industrial processes and biomedical applications. Given the current lack of detailed global gene expression studies on any Rhodococcus species, our study addresses a pressing need to identify tools and genes, such as F6 and rpf, that can enhance the capacity of Rhodococcus species for bioremediation, biosynthesis and pathogen control.
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Affiliation(s)
- Dana L Willner
- Data Science Program, William & Mary, Williamsburg, VA, USA
| | - Sudip Paudel
- Department of Biology, William & Mary, Williamsburg, VA, USA
- Wyss Institute, Harvard University, Cambridge, MA, USA
| | - Andrew D Halleran
- Department of Biology, William & Mary, Williamsburg, VA, USA
- Atalaya Capital Management, New York, NY, USA
| | - Grace E Solini
- Department of Biology, William & Mary, Williamsburg, VA, USA
- California Institute of Technology, Pasadena, CA, USA
| | - Veronica Gray
- Department of Biology, William & Mary, Williamsburg, VA, USA
- Georgetown University School of Medicine, Washington, DC, USA
| | - Margaret S Saha
- Department of Biology, William & Mary, Williamsburg, VA, USA.
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10
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Sachla AJ, Soni V, Piñeros M, Luo Y, Im JJ, Rhee KY, Helmann JD. The Bacillus subtilis yqgC-sodA operon protects magnesium-dependent enzymes by supporting manganese efflux. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.14.580342. [PMID: 38405924 PMCID: PMC10888875 DOI: 10.1101/2024.02.14.580342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Microbes encounter a myriad of stresses during their life cycle. Dysregulation of metal ion homeostasis is increasingly recognized as a key factor in host-microbe interactions. Bacterial metal ion homeostasis is tightly regulated by dedicated metalloregulators that control uptake, sequestration, trafficking, and efflux. Here, we demonstrate that deletion of the Bacillus subtilis yqgC-sodA (YS) complex operon, but not deletion of the individual genes, causes hypersensitivity to manganese (Mn). YqgC is an integral membrane protein of unknown function and SodA is a Mn-dependent superoxide dismutase (MnSOD). The YS strain has reduced expression of two Mn efflux proteins, MneP and MneS, consistent with the observed Mn sensitivity. The YS strain accumulated high levels of Mn, had increased reactive radical species (RRS), and had broad metabolic alterations that can be partially explained by the inhibition of Mg-dependent enzymes. Although the YS operon deletion strain and an efflux-deficient mneP mneS double mutant both accumulate Mn and have similar metabolic perturbations they also display phenotypic differences. Several mutations that suppressed Mn intoxication of the mneP mneS efflux mutant did not benefit the YS mutant. Further, Mn intoxication in the YS mutant, but not the mneP mneS strain, was alleviated by expression of Mg-dependent, chorismate-utilizing enzymes of the menaquinone, siderophore, and tryptophan (MST) family. Therefore, despite their phenotypic similarities, the Mn sensitivity in the mneP mneS and the yqgC-sodA deletion mutants results from distinct enzymatic vulnerabilities.
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Affiliation(s)
- Ankita J. Sachla
- Cornell University, Department of Microbiology, Ithaca, NY, 14853-8101, USA
| | - Vijay Soni
- Division of Infectious Diseases, Weill Department of Medicine, Weill Cornell Medicine, New York, NY 10065, USA
| | - Miguel Piñeros
- School of Integrative Plant Sciences, Plant Biology Section, Cornell University, Ithaca, NY 14853, USA
- Robert W. Holley Center for Agriculture and Health, USDA-ARS, Ithaca, NY 14853, USA
| | - Yuanchan Luo
- Cornell University, Department of Microbiology, Ithaca, NY, 14853-8101, USA
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Janice J. Im
- Cornell University, Department of Microbiology, Ithaca, NY, 14853-8101, USA
| | - Kyu Y. Rhee
- Division of Infectious Diseases, Weill Department of Medicine, Weill Cornell Medicine, New York, NY 10065, USA
| | - John D. Helmann
- Cornell University, Department of Microbiology, Ithaca, NY, 14853-8101, USA
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11
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Knez AM, Manenica M, Jelić Matošević Z, Bertoša B. Allosteric mechanism of MntR transcription factor from alkalophilic bacterium Halalkalibacterium halodurans. J Biomol Struct Dyn 2024:1-15. [PMID: 38345054 DOI: 10.1080/07391102.2024.2314265] [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: 12/06/2023] [Accepted: 01/28/2024] [Indexed: 03/11/2025]
Abstract
Bacterium Halalkalibacterium halodurans is an industrially important alkalophilic bacteria. It is recognized as a producer of enzymes such as β-galactosidase, xylanase, amylase and protease which are able to function at higher pH values and thus can be used in textile, food, paper industry and more. This bacterium, as any other bacterium, requires a sensitive mechanism for regulation of homeostasis of manganese ions (Mn2+) in order to survive. The key protein regulating this mechanism in H. halodurans is MntR - a transcriptional factor that binds to DNA and regulates the transcription of genes for proteins involved in manganese homeostasis. Long range all-atom molecular dynamics (MD) simulations, from 500 ns up to 1.25 µs, were used to study different forms of H. halodurans MntR in order to investigate the differences in the protein's structural and dynamical properties upon Mn2+ binding. Simulations revealed an allosteric mechanism which is activated by Mn2+ binding. The results of simulations show that Mn2+ binding alters the non-covalent interaction network of the protein structure which leads to a conformational change that primarily affects the positions of the DNA binding domains and, consequently, the DNA binding affinity of H. halodurans MntR. The key amino acid residues of the proposed mechanism were identified and their role in the proposed mechanism was computationally confirmed by MD simulations of in silico mutants.
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Affiliation(s)
- Ana Marija Knez
- Department of Chemistry, Faculty of Science, University of Zagreb, Zagreb, Croatia
| | - Martina Manenica
- Department of Chemistry, Faculty of Science, University of Zagreb, Zagreb, Croatia
| | - Zoe Jelić Matošević
- Department of Chemistry, Faculty of Science, University of Zagreb, Zagreb, Croatia
| | - Branimir Bertoša
- Department of Chemistry, Faculty of Science, University of Zagreb, Zagreb, Croatia
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12
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Lyon SE, Wencker FDR, Fernando CM, Harris KA, Breaker RR. Disruption of the bacterial OLE RNP complex impairs growth on alternative carbon sources. PNAS NEXUS 2024; 3:pgae075. [PMID: 38415217 PMCID: PMC10898510 DOI: 10.1093/pnasnexus/pgae075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Accepted: 02/06/2024] [Indexed: 02/29/2024]
Abstract
Ornate, large, extremophilic (OLE) RNAs comprise a class of large noncoding RNAs in bacteria whose members form a membrane-associated ribonucleoprotein (RNP) complex. This complex facilitates cellular adaptation to diverse stresses such as exposure to cold, short-chain alcohols, and elevated Mg2+ concentrations. Here, we report additional phenotypes exhibited by Halalkalibacterium halodurans (formerly called Bacillus halodurans) strains lacking functional OLE RNP complexes. Genetic disruption of the complex causes restricted growth compared to wild-type cells when cultured in minimal media (MM) wherein glucose is replaced with alternative carbon/energy sources. Genetic suppressor selections conducted in glutamate MM yielded isolates that carry mutations in or near genes relevant to Mn2+ homeostasis (ykoY and mntB), phosphate homeostasis (phoR), and putative multidrug resistance (bmrCD). These functional links between OLE RNA, carbon/energy management, and other fundamental processes including protein secretion are consistent with the hypothesis that the OLE RNP complex is a major contributor to cellular adaptation to unfavorable growth conditions.
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Affiliation(s)
- Seth E Lyon
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511, USA
| | - Freya D R Wencker
- Howard Hughes Medical Institute, Yale University, New Haven, CT 06511, USA
| | - Chrishan M Fernando
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511, USA
| | - Kimberly A Harris
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511, USA
| | - Ronald R Breaker
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511, USA
- Howard Hughes Medical Institute, Yale University, New Haven, CT 06511, USA
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511, USA
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13
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Bozsó Z, Lapat V, Ott PG, Móricz ÁM. Disparate Effects of Two Clerodane Diterpenes of Giant Goldenrod ( Solidago gigantea Ait.) on Bacillus spizizenii. Int J Mol Sci 2024; 25:1531. [PMID: 38338810 PMCID: PMC10855248 DOI: 10.3390/ijms25031531] [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: 12/30/2023] [Revised: 01/21/2024] [Accepted: 01/22/2024] [Indexed: 02/12/2024] Open
Abstract
New substances with antimicrobial properties are needed to successfully treat emerging human, animal, or plant pathogens. Seven clerodane diterpenes, previously isolated from giant goldenrod (Solidago gigantea) root, were tested against Gram-positive Bacillus subtilis, Bacillus spizizenii and Rhodococcus fascians by measuring minimal bactericidal concentration (MBC), minimal inhibitory concentration (MIC) and half-maximal inhibitory concentration (IC50). Two of them, Sg3a (a dialdehyde) and Sg6 (solidagoic acid B), were proved to be the most effective and were selected for further study. Bacillus spizizenii was incubated with the two diterpenes for shorter (1 h) or longer (5 h) periods and then subjected to genome-wide transcriptional analyses. Only a limited number of common genes (28 genes) were differentially regulated after each treatment, and these were mainly related to the restoration of cell membrane integrity and to membrane-related transports. Changes in gene activity indicated that, among other things, K+ and Na+ homeostasis, pH and membrane electron transport processes may have been affected. Activated export systems can be involved in the removal of harmful molecules from the bacterial cells. Inhibition of bacterial chemotaxis and flagellar assembly, as well as activation of genes for the biosynthesis of secondary metabolites, were observed as a general response. Depending on the diterpenes and the duration of the treatments, down-regulation of the protein synthesis-related, oxidative phosphorylation, signal transduction and transcription factor genes was found. In other cases, up-regulation of the genes of oxidation-reduction processes, sporulation and cell wall modification could be detected. Comparison of the effect of diterpenes with the changes induced by different environmental and nutritional conditions revealed several overlapping processes with stress responses. For example, the Sg6 treatment seems to have caused a starvation-like condition. In summary, there were both common and diterpene-specific changes in the transcriptome, and these changes were also dependent on the length of treatments. The results also indicated that Sg6 exerted its effect more slowly than Sg3a, but ultimately its effect was greater.
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Affiliation(s)
| | | | | | - Ágnes M. Móricz
- Plant Protection Institute, HUN-REN Centre for Agricultural Research, Herman Ottó Str. 15, H-1022 Budapest, Hungary; (Z.B.); (P.G.O.)
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14
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Khatun R, Modak R, Islam ASM, Moni D, Sepay N, Mukherjee R, Das G, Murmu N, Ali M. Small Molecule Interactions with Biomacromolecules: DNA Binding Interactions of a Manganese(III) Schiff Base Complex with Potential Anticancer Activities. ACS APPLIED BIO MATERIALS 2023; 6:3176-3188. [PMID: 37548990 DOI: 10.1021/acsabm.3c00297] [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: 08/08/2023]
Abstract
A manganese(III) complex, [MnIII(L)(SCN)(enH)](NO3)·H2O (1•H2O) (H2L = 2-((E)-(2-((E)-2-hydroxy-3-methoxybenzylidene-amino)-ethyl-imino)methyl)-6-methoxyphenol), has been synthesized and characterized by single-crystal X-ray diffraction analysis. The interaction of 1•H2O with DNA was studied by monitoring the decrease in absorbance of the complex at λ = 324 nm with the increase in DNA concentration, providing an opportunity to determine the binding constant of the 1•H2O-ct-DNA complex as 5.63 × 103 M-1. Similarly, fluorescence titration was carried out by adding ct-DNA gradually and monitoring the increase in emission intensity at 453 nm on excitation at λex = 324 nm. A linear form of the Benesi-Hildebrand equation yields a binding constant of 4.40 × 103 M-1 at 25 °C, establishing the self-consistency of our results obtained from absorption and fluorescence titrations. The competitive displacement reactions of dyes like ethidium bromide, Hoechst, and DAPI (4',6-diamidine-2'-phenylindole dihydrochloride) from dye-ct-DNA conjugates by 1•H2O were analyzed, and the corresponding KSV values are 1.05 × 104, 1.25 × 104, and 1.35 × 104 M-1 and the Kapp values are 2.16 × 103, 8.34 × 103, and 9.0 × 103 M-1, from which it is difficult to infer the preference of groove binding over intercalation by these DNA trackers. However, the molecular docking experiments and viscosity measurement clearly indicate the preference for minor groove binding over intercalation, involving a change in Gibbs free energy of -8.56 kcal/mol. The 1•H2O complex was then evaluated for its anticancer potential in breast cancer MCF-7 cells, which severely abrogates the growth of the cells in both 2D and 3D mammospheres, indicating its promising application as an anticancer drug through a minor groove binding interaction with ct-DNA.
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Affiliation(s)
- Rousunara Khatun
- Department of Chemistry, Jadavpur University, 188, Raja S. C. Mullick Road, Kolkata, West Bengal 700 032, India
- Aliah University, ll-A/27, Action Area II, Newtown, Action Area II, Kolkata, West Bengal 700160, India
| | - Ritwik Modak
- Department of Chemistry, Manipal Academy of Higher Education, Manipal Institute of Technology Bengaluru, Manipal 560064, India
| | - Abu Saleh Musha Islam
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2B, Raja S.C. Mullick Road, Kolkata, West Bengal 700032, India
| | - Dolan Moni
- Department of Chemistry, Jadavpur University, 188, Raja S. C. Mullick Road, Kolkata, West Bengal 700 032, India
| | - Nayim Sepay
- Department of Chemistry, Lady Brabourne College, Kolkata, West Bengal 700 017, India
| | - Rimi Mukherjee
- Department of Signal Transduction and Biogenic Amines, Chittanranjan National Cancer Institute, 37, S.P. Mukherjee Road, Kolkata, West Bengal 700 026, India
| | - Gaurav Das
- Department of Signal Transduction and Biogenic Amines, Chittanranjan National Cancer Institute, 37, S.P. Mukherjee Road, Kolkata, West Bengal 700 026, India
| | - Nabendu Murmu
- Department of Signal Transduction and Biogenic Amines, Chittanranjan National Cancer Institute, 37, S.P. Mukherjee Road, Kolkata, West Bengal 700 026, India
| | - Mahammad Ali
- Department of Chemistry, Jadavpur University, 188, Raja S. C. Mullick Road, Kolkata, West Bengal 700 032, India
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15
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Ogura M, Matsutani M, Asai K, Suzuki M. Glucose controls manganese homeostasis through transcription factors regulating known and newly identified manganese transporter genes in Bacillus subtilis. J Biol Chem 2023; 299:105069. [PMID: 37468100 PMCID: PMC10448178 DOI: 10.1016/j.jbc.2023.105069] [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: 06/15/2023] [Revised: 07/06/2023] [Accepted: 07/12/2023] [Indexed: 07/21/2023] Open
Abstract
Mn2+ is an essential nutrient whose concentration is tightly controlled in bacteria. In Bacillus subtilis, the Mn2+-activated transcription factor MntR controls Mn2+ transporter genes. However, factors regulating intracellular Mn2+ concentration are incompletely understood. Here, we found that glucose addition induces an increase in intracellular Mn2+ concentration. We determined this upshift was mediated by glucose induction of the major Mn2+ importer gene mntH by the transcription factor AhrC, which is known to be involved in arginine metabolism and to be indirectly induced by glucose. In addition, we identified novel AhrC-regulated genes encoding the Mn2+ importer YcsG and the ABC-type exporter YknUV. We found the expression of these genes was also regulated by glucose and contributes to the glucose induction of Mn2+ concentrations. ycsG expression is regulated by MntR as well. Furthermore, we analyzed the interaction of AhrC and MntR with the promoter driving ycsG expression and examined the Mn2+-dependent induction of this promoter to identify the transcription factors responsible for the Mn2+ induction. RNA-Seq revealed that disruption of ahrC and mntR affected the expression of 502 and 478 genes, respectively (false discovery rate, <0.001, log2[fold change] ≥ |2|. The AhrC- and/or MntR-dependent expression of twenty promoters was confirmed by LacZ analysis, and AhrC or MntR binding to some of these promoters was observed via EMSA. The finding that glucose promotes an increase in intracellular Mn2+ levels without changes in extracellular Mn2+ concentrations is reasonable for the bacterium, as intracellular Mn2+ is required for enzymes and pathways mediating glucose metabolism.
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Affiliation(s)
- Mitsuo Ogura
- Institute of Oceanic Research and Development, Tokai University, Shizuoka, Japan.
| | | | - Kei Asai
- Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan
| | - Michio Suzuki
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
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16
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Wu J, McAuliffe O, O'Byrne CP. Manganese uptake mediated by the NRAMP-type transporter MntH is required for acid tolerance in Listeria monocytogenes. Int J Food Microbiol 2023; 399:110238. [PMID: 37148667 DOI: 10.1016/j.ijfoodmicro.2023.110238] [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: 02/21/2023] [Revised: 04/25/2023] [Accepted: 04/27/2023] [Indexed: 05/08/2023]
Abstract
Listeria monocytogenes is a foodborne pathogen that is characterized by its ability to withstand mild stresses (i.e. cold, acid, salt) often encountered in food products or food processing environments. In the previous phenotypic and genotypic characterization of a collection of L. monocytogenes strains, we have identified one strain 1381, originally obtained from EURL-lm, as acid sensitive (reduced survival at pH 2.3) and extremely acid intolerant (no growth at pH 4.9, which supports the growth of most strains). In this study, we investigated the cause of acid intolerance in strain 1381 by isolating and sequencing reversion mutants that were capable of growth at low pH (pH 4.8) to a similar extent as another strain (1380) from the same MLST clonal complex (CC2). Whole genome sequencing showed that a truncation in mntH, which encodes a homologue of an NRAMP (Natural Resistance-Associated Macrophage Protein) type Mn2+ transporter, is responsible for the acid intolerance phenotype observed in strain 1381. However, the mntH truncation alone was not sufficient to explain the acid sensitivity of strain 1381 at lethal pH values as strain 1381R1 (a mntH+ revertant) exhibited similar acid survival to its parental strain at pH 2.3. Further growth experiments demonstrated that Mn2+ (but not Fe2+, Zn2+, Cu2+, Ca2+, or Mg2+) supplementation fully rescues the growth of strain 1381 under low pH conditions, suggesting that a Mn2+ limitation is the likely cause of growth arrest in the mntH- background. Consistent with the important role of Mn2+ in the acid stress response was the finding that mntH and mntB (both encoding Mn2+ transporters) had higher transcription levels following exposure to mild acid stress (pH 5). Taken together, these results provide evidence that MntH-mediated Mn2+ uptake is essential for the growth of L. monocytogenes under low pH conditions. Moreover, since strain 1381 was recommended for conducting food challenge studies by the European Union Reference Laboratory, the use of this strain in evaluating the growth of L. monocytogenes in low pH environments where Mn2+ is scarce should be reconsidered. Furthermore, since it is unknown when strain 1381 acquired the mntH frameshift mutation, the ability of the strains used for challenge studies to grow under food-related stresses needs to be routinely validated.
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Affiliation(s)
- Jialun Wu
- Bacterial Stress Response Group, Microbiology, Ryan Institute, School of Biological & Chemical Sciences, University of Galway, Galway H91 TK33, Ireland
| | | | - Conor P O'Byrne
- Bacterial Stress Response Group, Microbiology, Ryan Institute, School of Biological & Chemical Sciences, University of Galway, Galway H91 TK33, Ireland..
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17
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Steingard CH, Pinochet-Barros A, Wendel BM, Helmann JD. Iron homeostasis in Bacillus subtilis relies on three differentially expressed efflux systems. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001289. [PMID: 36748638 PMCID: PMC9993123 DOI: 10.1099/mic.0.001289] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
In Bacillus subtilis, iron homeostasis is maintained by the ferric uptake regulator (Fur) and manganese homeostasis relies on the manganese transport regulator (MntR). Both Fur and MntR function as bi-functional metalloregulators that repress import and activate metal ion efflux systems. The ferrous iron efflux ATPase, PfeT, is derepressed by hydrogen peroxide (H2O2) as sensed by PerR and induced by iron as sensed by Fur. Mutants lacking PfeT are sensitive to iron intoxication. Here, we show that mntR mutants are also iron-sensitive, largely due to decreased expression of the MntR-activated MneP and MneS cation diffusion facilitator (CDF) proteins previously defined for their role in Mn2+ export. The ability of MneP and MneS to export iron is apparent even when their expression is not induced by Mn2+. Our results demonstrate that PfeT, MneP and MneS each contribute to iron homeostasis, and a triple mutant lacking all three is more iron-sensitive than any single mutant. We further show that sensitivity to H2O2 does not correlate with iron sensitivity. For example, an mntR mutant is H2O2-sensitive due to elevated Mn(II) that increases PerR-mediated repression of peroxide resistance genes, and this repression is antagonized by elevated Fe2+ in an mntR pfeT mutant. Thus, H2O2-sensitivity reflects the relative levels of Mn2+ and Fe2+ as sensed by the PerR regulatory protein. These results underscore the complex interplay between manganese, iron and oxidative stress in B. subtilis.
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Affiliation(s)
- Caroline H Steingard
- Department of Microbiology, Cornell University, Ithaca, New York 14853-8101, USA
| | - Azul Pinochet-Barros
- Department of Microbiology, Cornell University, Ithaca, New York 14853-8101, USA
| | - Brian M Wendel
- Department of Microbiology, Cornell University, Ithaca, New York 14853-8101, USA
| | - John D Helmann
- Department of Microbiology, Cornell University, Ithaca, New York 14853-8101, USA
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18
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Peng W, Yang X, Wang Y, Wang N, Li X, Chen H, Yuan F, Bei W. Mn uptake system affects the virulence of Streptococcus suis by mediating oxidative stress. Vet Microbiol 2022; 272:109518. [PMID: 35926476 DOI: 10.1016/j.vetmic.2022.109518] [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] [Received: 07/17/2022] [Accepted: 07/26/2022] [Indexed: 10/16/2022]
Abstract
Manganese (Mn) is an important micronutrient that is not readily available to pathogens during infection. Hosts resist the invasion of pathogens through nutritional immunity and oxidative stress. To overcome this nutrient restriction, bacteria utilize high affinity transporters to compete with nutrient-binding proteins (e.g., calprotectin). Little is known about the role of Mn in the pathophysiology of Streptococcus suis. Here, we revealed that the tolerance of S. suis to calprotectin and oxidative stress was associated with Mn. Inactivation of Mn uptake system, TroABCD, in S. suis decreased the tolerance to calprotectin and oxidative stress. Furthermore, Mn uptake system mutant strains reduced capacity for bacterial cellular survival, and attenuated virulence in a mouse model. To explore the regulatory mechanism, we determined the transcriptional start site of troABCD using capping rapid amplification of cDNA ends. Furthermore, we revealed that TroR was a transcriptional regulatory repressor of troABCD. In the absence of troR, transcription levels of troA, troB, troC, and troD were not inhibited by low or high Mn levels, and intracellular Mn contents of mutant strains were higher than that of the wild-type strain. Finally, we used electrophoretic mobility shift assay to demonstrate that TroR bound the promoter region of troABCD. Collectively, this study revealed that Mn acquisition was essential for pathogenesis of S. suis and Mn uptake systems should be targets for the development of new antimicrobials.
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Affiliation(s)
- Wei Peng
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China; The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Xia Yang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China; The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Yanna Wang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China; The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Ningning Wang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China; The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Xiaoyue Li
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China; The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Huanchun Chen
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China; The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Fangyan Yuan
- Key Laboratory of Prevention and Control Agents for Animal Bacteriosis (Ministry of Agriculture), Institute of Animal Husbandry and Veterinary Sciences, Hubei Academy of Agricultural Sciences, Wuhan, China.
| | - Weicheng Bei
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China; Hubei Hongshan Laboratory, Wuhan, China; The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China; Guangxi Yangxiang Co., Ltd, China.
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19
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Wendel BM, Pi H, Krüger L, Herzberg C, Stülke J, Helmann JD. A Central Role for Magnesium Homeostasis during Adaptation to Osmotic Stress. mBio 2022; 13:e0009222. [PMID: 35164567 PMCID: PMC8844918 DOI: 10.1128/mbio.00092-22] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 01/18/2022] [Indexed: 02/06/2023] Open
Abstract
Osmotic stress is a significant physical challenge for free-living cells. Cells from all three domains of life maintain viability during osmotic stress by tightly regulating the major cellular osmolyte potassium (K+) and by import or synthesis of compatible solutes. It has been widely established that in response to high salt stress, many bacteria transiently accumulate high levels of K+, leading to bacteriostasis, with growth resuming only when compatible solutes accumulate and K+ levels are restored to biocompatible levels. Using Bacillus subtilis as a model system, we provide evidence that K+ fluxes perturb Mg2+ homeostasis: import of K+ upon osmotic upshift is correlated with Mg2+ efflux, and Mg2+ reimport is critical for adaptation. The transient growth inhibition resulting from hyperosmotic stress is coincident with loss of Mg2+ and a decrease in protein translation. Conversely, the reimport of Mg2+ is a limiting factor during resumption of growth. Furthermore, we show the essential signaling dinucleotide cyclic di-AMP fluctuates dynamically in coordination with Mg2+ and K+ levels, consistent with the proposal that cyclic di-AMP orchestrates the cellular response to osmotic stress. IMPORTANCE Environments with high concentrations of salt or other solutes impose an osmotic stress on cells, ultimately limiting viability by dehydration of the cytosol. A very common cellular response to high osmolarity is to immediately import high levels of potassium ion (K+), which helps prevent dehydration and allows time for the import or synthesis of biocompatible solutes that allow a resumption of growth. Here, using Bacillus subtilis as a model, we demonstrate that concomitant with K+ import there is a large reduction in intracellular magnesium (Mg2+) mediated by specific efflux pumps. Further, it is the reimport of Mg2+ that is rate-limiting for the resumption of growth. These coordinated fluxes of K+ and Mg2+ are orchestrated by cyclic-di-AMP, an essential second messenger in Firmicutes. These findings amend the conventional model for osmoadaptation and reveal that Mg2+ limitation is the proximal cause of the bacteriostasis that precedes resumption of growth.
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Affiliation(s)
- Brian M. Wendel
- Department of Microbiology, Cornell University, Ithaca, New York, USA
| | - Hualiang Pi
- Department of Microbiology, Cornell University, Ithaca, New York, USA
| | - Larissa Krüger
- Department of General Microbiology, GZMB, Georg August University, Göttingen, Germany
| | - Christina Herzberg
- Department of General Microbiology, GZMB, Georg August University, Göttingen, Germany
| | - Jörg Stülke
- Department of General Microbiology, GZMB, Georg August University, Göttingen, Germany
| | - John D. Helmann
- Department of Microbiology, Cornell University, Ithaca, New York, USA
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20
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A Unique Reverse Adaptation Mechanism Assists Bordetella pertussis in Resistance to Both Scarcity and Toxicity of Manganese. mBio 2021; 12:e0190221. [PMID: 34700381 PMCID: PMC8546581 DOI: 10.1128/mbio.01902-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The ability of bacterial pathogens to acquire essential micronutrients is critical for their survival in the host environment. Manganese plays a complex role in the virulence of a variety of pathogens due to its function as an antioxidant and enzymatic cofactor. Therefore, host cells deprive pathogens of manganese to prevent or attenuate infection. Here, we show that evolution of the human-restricted pathogen Bordetella pertussis has selected for an inhibitory duplication within a manganese exporter of the calcium:cation antiporter superfamily. Intriguingly, upon exposure to toxic levels of manganese, the nonfunctional exporter becomes operative in resister cells due to a unique reverse adaptation mechanism. However, compared with wild-type (wt) cells, the resisters carrying a functional copy of the exporter displayed strongly reduced intracellular levels of manganese and impaired growth under oxidative stress. Apparently, inactivation of the manganese exporter and the resulting accumulation of manganese in the cytosol benefited the pathogen by improving its survival under stress conditions. The inhibitory duplication within the exporter gene is highly conserved among B. pertussis strains, absent from all other Bordetella species and from a vast majority of organisms across all kingdoms of life. Therefore, we conclude that inactivation of the exporter gene represents an exceptional example of a flexible genome decay strategy employed by a human pathogen to adapt to its exclusive host.
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21
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Liu H, Zhang Y, Wang Y, Xie X, Shi Q. The Connection between Czc and Cad Systems Involved in Cadmium Resistance in Pseudomonas putida. Int J Mol Sci 2021; 22:ijms22189697. [PMID: 34575861 PMCID: PMC8469834 DOI: 10.3390/ijms22189697] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 09/01/2021] [Accepted: 09/03/2021] [Indexed: 12/23/2022] Open
Abstract
Heavy metal pollution is widespread and persistent, and causes serious harm to the environment. Pseudomonas putida, a representative environmental microorganism, has strong resistance to heavy metals due to its multiple efflux systems. Although the functions of many efflux systems have been well-studied, the relationship between them remains unclear. Here, the relationship between the Czc and Cad systems that are predominantly responsible for cadmium efflux in P. putida KT2440 is identified. The results demonstrated that CzcR3, the response regulator of two-component system CzcRS3 in the Czc system, activates the expression of efflux pump genes czcCBA1 and czcCBA2 by directly binding to their promoters, thereby helping the strain resist cadmium stress. CzcR3 can also bind to its own promoter, but it has only a weak regulatory effect. The high-level expression of czcRS3 needs to be induced by Cd2+, and this relies on the regulation of CadR, a key regulator in the Cad system, which showed affinity to czcRS3 promoter. Our study indicates that the Cad system is involved in the regulation of the Czc system, and this relationship is important for maintaining the considerable resistance to cadmium in P. putida.
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22
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Kuznetsova A, Masrati G, Vigonsky E, Livnat-Levanon N, Rose J, Grupper M, Baloum A, Yang JG, Rees DC, Ben-Tal N, Lewinson O. Titratable transmembrane residues and a hydrophobic plug are essential for manganese import via the Bacillus anthracis ABC transporter MntBC-A. J Biol Chem 2021; 297:101087. [PMID: 34416234 PMCID: PMC8487065 DOI: 10.1016/j.jbc.2021.101087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 08/12/2021] [Accepted: 08/16/2021] [Indexed: 11/07/2022] Open
Abstract
All extant life forms require trace transition metals (e.g., Fe2/3+, Cu1/2+, and Mn2+) to survive. However, as these are environmentally scarce, organisms have evolved sophisticated metal uptake machineries. In bacteria, high-affinity import of transition metals is predominantly mediated by ABC transporters. During bacterial infection, sequestration of metal by the host further limits the availability of these ions, and accordingly, bacterial ABC transporters (importers) of metals are key virulence determinants. However, the structure–function relationships of these metal transporters have not been fully elucidated. Here, we used metal-sensitivity assays, advanced structural modeling, and enzymatic assays to study the ABC transporter MntBC-A, a virulence determinant of the bacterial human pathogen Bacillus anthracis. We find that despite its broad metal-recognition profile, MntBC-A imports only manganese, whereas zinc can function as a high-affinity inhibitor of MntBC-A. Computational analysis shows that the transmembrane metal permeation pathway is lined with six titratable residues that can coordinate the positively charged metal, and mutagenesis studies show that they are essential for manganese transport. Modeling suggests that access to these titratable residues is blocked by a ladder of hydrophobic residues, and ATP-driven conformational changes open and close this hydrophobic seal to permit metal binding and release. The conservation of this arrangement of titratable and hydrophobic residues among ABC transporters of transition metals suggests a common mechanism. These findings advance our understanding of transmembrane metal recognition and permeation and may aid the design and development of novel antibacterial agents.
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Affiliation(s)
- Anastasiya Kuznetsova
- Department of Molecular Microbiology and the Rappaport Institute for Medical Sciences, Faculty of Medicine, The Technion-Israel Institute of Technology, Haifa, Israel
| | - Gal Masrati
- Department of Biochemistry and Molecular Biology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Elena Vigonsky
- Department of Molecular Microbiology and the Rappaport Institute for Medical Sciences, Faculty of Medicine, The Technion-Israel Institute of Technology, Haifa, Israel
| | - Nurit Livnat-Levanon
- Department of Molecular Microbiology and the Rappaport Institute for Medical Sciences, Faculty of Medicine, The Technion-Israel Institute of Technology, Haifa, Israel
| | - Jessica Rose
- Department of Molecular Microbiology and the Rappaport Institute for Medical Sciences, Faculty of Medicine, The Technion-Israel Institute of Technology, Haifa, Israel
| | - Moti Grupper
- Infectious Disease Unit, Rambam Health Care Campus, Haifa, Israel
| | - Adan Baloum
- Department of Molecular Microbiology and the Rappaport Institute for Medical Sciences, Faculty of Medicine, The Technion-Israel Institute of Technology, Haifa, Israel
| | - Janet G Yang
- Department of Chemistry, University of San Francisco, San Francisco, California, USA
| | - Douglas C Rees
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, USA
| | - Nir Ben-Tal
- Department of Biochemistry and Molecular Biology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Oded Lewinson
- Department of Molecular Microbiology and the Rappaport Institute for Medical Sciences, Faculty of Medicine, The Technion-Israel Institute of Technology, Haifa, Israel.
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23
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Analysis of the Manganese and MntR Regulon in Corynebacterium diphtheriae. J Bacteriol 2021; 203:e0027421. [PMID: 34370555 DOI: 10.1128/jb.00274-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Corynebacterium diphtheriae is the causative agent of a severe respiratory disease in humans. The bacterial systems required for infection are poorly understood, but the acquisition of metals such as manganese (Mn) is likely critical for host colonization. MntR is a Mn-dependent transcriptional regulator in C. diphtheriae that represses the expression of the mntABCD genes, which encode a putative ABC metal transporter. However, other targets of Mn and MntR regulation in C. diphtheriae have not been identified. In this study, we use comparisons between the gene expression profiles of wild-type C. diphtheriae strain 1737 grown without or with Mn supplementation and comparisons of gene expression between wild-type and an mntR deletion mutant to characterize the C. diphtheriae Mn and MntR regulon. MntR was observed to both repress and induce various target genes in a Mn-dependent manner. Genes induced by MntR include the Mn-superoxide dismutase, sodA, and the putative ABC transporter locus, iutABCD. DNA binding studies showed that MntR interacts with the promoter regions for several genes identified in the expression study, and a 17-bp consensus MntR DNA binding site was identified. We found that an mntR mutant displayed increased sensitivity to Mn and cadmium that could be alleviated by the additional deletion of the mntABCD transport locus, providing evidence that the MntABCD transporter functions as a Mn uptake system in C. diphtheriae. The findings in this study further our understanding of metal uptake systems and global metal regulatory networks in this important human pathogen. Importance Mechanisms for metal scavenging are critical to the survival and success of bacterial pathogens, including Corynebacterium diphtheriae. Metal import systems in pathogenic bacteria have been studied as possible vaccine components due to high conservation, critical functionality, and surface localization. In this study, we expand our understanding of the genes controlled by the global manganese regulator, MntR. We determined a role for the MntABCD transporter in manganese import using evidence from manganese and cadmium toxicity assays. Understanding the nutritional requirements of C. diphtheriae and the tools used to acquire essential metals will aid in the development of future vaccines.
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van Gijtenbeek LA, Singer Q, Steffensen LE, Neuens S, Guldager HS, Bidstrup S, Høgholm T, Madsen MG, Glass K, Siedler S. Lacticaseibacillus rhamnosus Impedes Growth of Listeria spp. in Cottage Cheese through Manganese Limitation. Foods 2021; 10:1353. [PMID: 34208094 PMCID: PMC8230772 DOI: 10.3390/foods10061353] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 06/01/2021] [Accepted: 06/04/2021] [Indexed: 01/25/2023] Open
Abstract
Acidification and nutrient depletion by dairy starter cultures is often sufficient to prevent outgrowth of pathogens during post-processing of cultured dairy products. In the case of cottage cheese, however, the addition of cream dressing to the curd and subsequent cooling procedures can create environments that may be hospitable for the growth of Listeria monocytogenes. We report on a non-bacterio-cinogenic Lacticaseibacillus rhamnosus strain that severely limits the growth potential of L. monocytogenes in creamed cottage cheese. The main mechanism underlying Listeria spp. inhibition was found to be caused by depletion of manganese (Mn), thus through competitive exclusion of a trace element essential for the growth of many microorganisms. Growth of Streptococcus thermophilus and Lactococcus lactis that constitute the starter culture, on the other hand, were not influenced by reduced Mn levels. Addition of L. rhamnosus with Mn-based bioprotective properties during cottage cheese production therefore offers a solution to inhibit undesired bacteria in a bacteriocin-independent fashion.
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Affiliation(s)
- Lieke A. van Gijtenbeek
- Chr. Hansen A/S, Bøge Alle 10-12, DK-2970 Hørsholm, Denmark; (L.A.v.G.); (L.E.S.); (S.N.); (H.S.G.); (S.B.); (T.H.); (M.G.M.)
| | - Quinn Singer
- Food Research Institute, University of Wisconsin-Madison, 1550 Linden Drive, Madison, WI 53706, USA; (Q.S.); (K.G.)
| | - Louise E. Steffensen
- Chr. Hansen A/S, Bøge Alle 10-12, DK-2970 Hørsholm, Denmark; (L.A.v.G.); (L.E.S.); (S.N.); (H.S.G.); (S.B.); (T.H.); (M.G.M.)
| | - Shannon Neuens
- Chr. Hansen A/S, Bøge Alle 10-12, DK-2970 Hørsholm, Denmark; (L.A.v.G.); (L.E.S.); (S.N.); (H.S.G.); (S.B.); (T.H.); (M.G.M.)
| | - Helle S. Guldager
- Chr. Hansen A/S, Bøge Alle 10-12, DK-2970 Hørsholm, Denmark; (L.A.v.G.); (L.E.S.); (S.N.); (H.S.G.); (S.B.); (T.H.); (M.G.M.)
| | - Susanne Bidstrup
- Chr. Hansen A/S, Bøge Alle 10-12, DK-2970 Hørsholm, Denmark; (L.A.v.G.); (L.E.S.); (S.N.); (H.S.G.); (S.B.); (T.H.); (M.G.M.)
| | - Tina Høgholm
- Chr. Hansen A/S, Bøge Alle 10-12, DK-2970 Hørsholm, Denmark; (L.A.v.G.); (L.E.S.); (S.N.); (H.S.G.); (S.B.); (T.H.); (M.G.M.)
| | - Mikkel G. Madsen
- Chr. Hansen A/S, Bøge Alle 10-12, DK-2970 Hørsholm, Denmark; (L.A.v.G.); (L.E.S.); (S.N.); (H.S.G.); (S.B.); (T.H.); (M.G.M.)
| | - Kathleen Glass
- Food Research Institute, University of Wisconsin-Madison, 1550 Linden Drive, Madison, WI 53706, USA; (Q.S.); (K.G.)
| | - Solvej Siedler
- Chr. Hansen A/S, Bøge Alle 10-12, DK-2970 Hørsholm, Denmark; (L.A.v.G.); (L.E.S.); (S.N.); (H.S.G.); (S.B.); (T.H.); (M.G.M.)
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25
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Sachla AJ, Luo Y, Helmann JD. Manganese impairs the QoxABCD terminal oxidase leading to respiration-associated toxicity. Mol Microbiol 2021; 116:729-742. [PMID: 34097790 DOI: 10.1111/mmi.14767] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 06/02/2021] [Accepted: 06/03/2021] [Indexed: 11/29/2022]
Abstract
Cell physiology relies on metalloenzymes and can be easily disrupted by imbalances in metal ion pools. Bacillus subtilis requires manganese for growth and has highly regulated mechanisms for import and efflux that help maintain homeostasis. Cells defective for manganese (Mn) efflux are highly sensitive to intoxication, but the processes impaired by Mn excess are often unknown. Here, we employed a forward genetics approach to identify pathways affected by manganese intoxication. Our results highlight a central role for the membrane-localized electron transport chain in metal intoxication during aerobic growth. In the presence of elevated manganese, there is an increased generation of reactive radical species associated with dysfunction of the major terminal oxidase, the cytochrome aa3 heme-copper menaquinol oxidase (QoxABCD). Intoxication is suppressed by diversion of menaquinol to alternative oxidases or by a mutation affecting heme A synthesis that is known to convert QoxABCD from an aa3 to a bo3 -type oxidase. Manganese sensitivity is also reduced by derepression of the MhqR regulon, which protects cells against reactive quinones. These results suggest that dysfunction of the cytochrome aa3 -type quinol oxidase contributes to metal-induced intoxication.
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Affiliation(s)
- Ankita J Sachla
- Department of Microbiology, Cornell University, Ithaca, NY, USA
| | - Yuanchan Luo
- Department of Microbiology, Cornell University, Ithaca, NY, USA.,State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - John D Helmann
- Department of Microbiology, Cornell University, Ithaca, NY, USA
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26
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Bosma EF, Rau MH, van Gijtenbeek LA, Siedler S. Regulation and distinct physiological roles of manganese in bacteria. FEMS Microbiol Rev 2021; 45:6284802. [PMID: 34037759 PMCID: PMC8632737 DOI: 10.1093/femsre/fuab028] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 05/21/2021] [Indexed: 02/06/2023] Open
Abstract
Manganese (Mn2+) is an essential trace element within organisms spanning the entire tree of life. In this review, we provide an overview of Mn2+ transport and the regulation of its homeostasis in bacteria, with a focus on its functions beyond being a cofactor for enzymes. Crucial differences in Mn2+ homeostasis exist between bacterial species that can be characterized to have an iron- or manganese-centric metabolism. Highly iron-centric species require minimal Mn2+ and mostly use it as a mechanism to cope with oxidative stress. As a consequence, tight regulation of Mn2+ uptake is required, while organisms that use both Fe2+ and Mn2+ need other layers of regulation for maintaining homeostasis. We will focus in detail on manganese-centric bacterial species, in particular lactobacilli, that require little to no Fe2+ and use Mn2+ for a wider variety of functions. These organisms can accumulate extraordinarily high amounts of Mn2+ intracellularly, enabling the nonenzymatic use of Mn2+ for decomposition of reactive oxygen species while simultaneously functioning as a mechanism of competitive exclusion. We further discuss how Mn2+ accumulation can provide both beneficial and pathogenic bacteria with advantages in thriving in their niches.
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Affiliation(s)
- Elleke F Bosma
- Chr. Hansen A/S, Discovery, R&D, 2970 Hoersholm, Denmark
| | - Martin H Rau
- Chr. Hansen A/S, Discovery, R&D, 2970 Hoersholm, Denmark
| | | | - Solvej Siedler
- Corresponding author: Boege Allé 10-12, 2970 Hoersholm, Denmark. Tel: +45 52 18 08 25; E-mail:
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27
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Wang H, Zhang Y, Bartlett DH, Xiao X. Transcriptomic Analysis Reveals Common Adaptation Mechanisms Under Different Stresses for Moderately Piezophilic Bacteria. MICROBIAL ECOLOGY 2021; 81:617-629. [PMID: 32995929 DOI: 10.1007/s00248-020-01609-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 09/21/2020] [Indexed: 06/11/2023]
Abstract
Piezophiles, by the commonly accepted definition, grow faster under high hydrostatic pressure (HHP) than under ambient pressure and are believed to exist only in pressurized environments where life has adapted to HHP during evolution. However, recent findings suggest that piezophiles have developed a common adaptation strategy to cope with multiple types of stresses including HHP. These results raise a question on the ecological niches of piezophiles: are piezophiles restricted to habitats with HHP? In this study, we observed that the bacterial strains Sporosarcina psychrophila DSM 6497 and Lysinibacillus sphaericus LMG 22257, which were isolated from surface environments and then transferred under ambient pressure for half a century, possess moderately piezophilic characteristics with optimal growth pressures of 7 and 20 MPa, respectively. Their tolerance to HHP was further enhanced by MgCl2 supplementation under the highest tested pressure of 50 MPa. Transcriptomic analysis was performed to compare gene expression with and without MgCl2 supplementation under 50 MPa for S. psychrophila DSM 6497. Among 4390 genes or transcripts obtained, 915 differentially expressed genes (DEGs) were identified. These DEGs are primarily associated with the antioxidant defense system, intracellular compatible solute accumulation, and membrane lipid biosynthesis, which have been reported to be essential for cells to cope with HHP. These findings indicate no in situ pressure barrier for piezophile isolation, and cells may adopt a common adaptation strategy to cope with different stresses.
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Affiliation(s)
- Han Wang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Yu Zhang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.
- School of Oceanography, Shanghai Jiao Tong University, Shanghai, China.
- State Key Laboratory of Ocean Engineering, School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai, China.
| | - Douglas H Bartlett
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, USA
| | - Xiang Xiao
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
- State Key Laboratory of Ocean Engineering, School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai, China
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, China
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28
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Arjes HA, Willis L, Gui H, Xiao Y, Peters J, Gross C, Huang KC. Three-dimensional biofilm colony growth supports a mutualism involving matrix and nutrient sharing. eLife 2021; 10:e64145. [PMID: 33594973 PMCID: PMC7925131 DOI: 10.7554/elife.64145] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 02/15/2021] [Indexed: 12/16/2022] Open
Abstract
Life in a three-dimensional biofilm is typical for many bacteria, yet little is known about how strains interact in this context. Here, we created essential gene CRISPR interference knockdown libraries in biofilm-forming Bacillus subtilis and measured competitive fitness during colony co-culture with wild type. Partial knockdown of some translation-related genes reduced growth rates and led to out-competition. Media composition led some knockdowns to compete differentially as biofilm versus non-biofilm colonies. Cells depleted for the alanine racemase AlrA died in monoculture but survived in a biofilm colony co-culture via nutrient sharing. Rescue was enhanced in biofilm colony co-culture with a matrix-deficient parent due to a mutualism involving nutrient and matrix sharing. We identified several examples of mutualism involving matrix sharing that occurred in three-dimensional biofilm colonies but not when cultured in two dimensions. Thus, growth in a three-dimensional colony can promote genetic diversity through sharing of secreted factors and may drive evolution of mutualistic behavior.
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Affiliation(s)
- Heidi A Arjes
- Department of Bioengineering, Stanford University School of MedicineStanfordUnited States
| | - Lisa Willis
- Department of Bioengineering, Stanford University School of MedicineStanfordUnited States
| | - Haiwen Gui
- Department of Bioengineering, Stanford University School of MedicineStanfordUnited States
| | - Yangbo Xiao
- Department of Bioengineering, Stanford University School of MedicineStanfordUnited States
| | - Jason Peters
- Department of Cell and Tissue Biology, University of California San FranciscoSan FranciscoUnited States
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-MadisonMadisonUnited States
- Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, University of Wisconsin-MadisonMadisonUnited States
- Department of Bacteriology, University of Wisconsin-MadisonMadisonUnited States
- Department of Medical Microbiology and Immunology, University of Wisconsin-MadisonMadisonUnited States
| | - Carol Gross
- Department of Cell and Tissue Biology, University of California San FranciscoSan FranciscoUnited States
| | - Kerwyn Casey Huang
- Department of Bioengineering, Stanford University School of MedicineStanfordUnited States
- Department of Microbiology & Immunology, Stanford University School of MedicineStanfordUnited States
- Chan Zuckerberg BiohubSan FranciscoUnited States
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29
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Xia X, Wu S, Zhou Z, Wang G. Microbial Cd(II) and Cr(VI) resistance mechanisms and application in bioremediation. JOURNAL OF HAZARDOUS MATERIALS 2021; 401:123685. [PMID: 33113721 DOI: 10.1016/j.jhazmat.2020.123685] [Citation(s) in RCA: 103] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 07/16/2020] [Accepted: 08/05/2020] [Indexed: 05/21/2023]
Abstract
The heavy metals cadmium (Cd) and chromium (Cr) are extensively used in industry and result in water and soil contamination. The highly toxic Cd(II) and Cr(VI) are the most common soluble forms of Cd and Cr, respectively. They enter the human body through the food chain and drinking water and then cause serious illnesses. Microorganisms can adsorb metals or transform Cd(II) and Cr(VI) into insoluble or less bioavailable forms, and such strategies are applicable in Cd and Cr bioremediation. This review focuses on the highlighting of novel achievements on microbial Cd(II) and Cr(VI) resistance mechanisms and their bioremediation applications. In addition, the knowledge gaps and research perspectives are also discussed in order to build a bridge between the theoretical breakthrough and the resolution of Cd(II) and Cr(VI) contamination problems.
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Affiliation(s)
- Xian Xia
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China; Hubei Key Laboratory of Edible Wild Plants Conservation & Utilization, Hubei Engineering Research Center of Special Wild Vegetables Breeding and Comprehensive Utilization Technology, National Experimental Teaching Demonstrating Center, College of Life Sciences, Hubei Normal University, Huangshi, 435002, PR China
| | - Shijuan Wu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China
| | - Zijie Zhou
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China
| | - Gejiao Wang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China.
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30
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Al-Tameemi H, Beavers WN, Norambuena J, Skaar EP, Boyd JM. Staphylococcus aureus lacking a functional MntABC manganese import system has increased resistance to copper. Mol Microbiol 2020; 115:554-573. [PMID: 33034093 DOI: 10.1111/mmi.14623] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 09/28/2020] [Accepted: 10/04/2020] [Indexed: 12/17/2022]
Abstract
S. aureus USA300 isolates utilize the copBL and copAZ gene products to prevent Cu intoxication. We created and examined a ΔcopAZ ΔcopBL mutant strain (cop-). The cop- strain was sensitive to Cu and accumulated intracellular Cu. We screened a transposon (Tn) mutant library in the cop- background and isolated strains with Tn insertions in the mntABC operon that permitted growth in the presence of Cu. The mutations were in mntA and they were recessive. Under the growth conditions utilized, MntABC functioned in manganese (Mn) import. When cultured with Cu, strains containing a mntA::Tn accumulated less Cu than the parent strain. Mn(II) supplementation improved growth when cop- was cultured with Cu and this phenotype was dependent upon the presence of MntR, which is a repressor of mntABC transcription. A ΔmntR strain had an increased Cu load and decreased growth in the presence of Cu, which was abrogated by the introduction of mntA::Tn. Over-expression of mntABC increased cellular Cu load and sensitivity to Cu. The presence of a mntA::Tn mutation protected iron-sulfur (FeS) enzymes from inactivation by Cu. The data presented are consistent with a model wherein defective MntABC results in decreased cellular Cu accumulation and protection to FeS enzymes from Cu poisoning.
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Affiliation(s)
- Hassan Al-Tameemi
- Department of Biochemistry and Microbiology, Rutgers, the State University of New Jersey, New Brunswick, NJ, USA
| | - William N Beavers
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Javiera Norambuena
- Department of Biochemistry and Microbiology, Rutgers, the State University of New Jersey, New Brunswick, NJ, USA
| | - Eric P Skaar
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Jeffrey M Boyd
- Department of Biochemistry and Microbiology, Rutgers, the State University of New Jersey, New Brunswick, NJ, USA
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31
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Costa OYA, Oguejiofor C, Zühlke D, Barreto CC, Wünsche C, Riedel K, Kuramae EE. Impact of Different Trace Elements on the Growth and Proteome of Two Strains of Granulicella, Class "Acidobacteriia". Front Microbiol 2020; 11:1227. [PMID: 32625179 PMCID: PMC7315648 DOI: 10.3389/fmicb.2020.01227] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 05/14/2020] [Indexed: 12/24/2022] Open
Abstract
Acidobacteria represents one of the most dominant bacterial groups across diverse ecosystems. However, insight into their ecology and physiology has been hampered by difficulties in cultivating members of this phylum. Previous cultivation efforts have suggested an important role of trace elements for the proliferation of Acidobacteria, however, the impact of these metals on their growth and metabolism is not known. In order to gain insight into this relationship, we evaluated the effect of trace element solution SL10 on the growth of two strains (5B5 and WH15) of Acidobacteria belonging to the genus Granulicella and studied the proteomic responses to manganese (Mn). Granulicella species had highest growth with the addition of Mn, as well as higher tolerance to this metal compared to seven other metal salts. Variations in tolerance to metal salt concentrations suggests that Granulicella sp. strains possess different mechanisms to deal with metal ion homeostasis and stress. Furthermore, Granulicella sp. 5B5 might be more adapted to survive in an environment with higher concentration of several metal ions when compared to Granulicella sp. WH15. The proteomic profiles of both strains indicated that Mn was more important in enhancing enzymatic activity than to protein expression regulation. In the genomic analyses, we did not find the most common transcriptional regulation of Mn homeostasis, but we found candidate transporters that could be potentially involved in Mn homeostasis for Granulicella species. The presence of such transporters might be involved in tolerance to higher Mn concentrations, improving the adaptability of bacteria to metal enriched environments, such as the decaying wood-rich Mn environment from which these two Granulicella strains were isolated.
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Affiliation(s)
- Ohana Y A Costa
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, Netherlands.,Institute of Biology Leiden, Leiden University, Leiden, Netherlands
| | - Chidinma Oguejiofor
- Department of Soil Science and Meteorology, Michael Okpara University of Agriculture, Umudike, Nigeria
| | - Daniela Zühlke
- Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Cristine C Barreto
- Genomic Sciences and Biotechnology Program, Catholic University of Brasilia, Distrito Federal, Brazil
| | - Christine Wünsche
- Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Katharina Riedel
- Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Eiko E Kuramae
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, Netherlands.,Ecology and Biodiversity, Institute of Environmental Biology, Utrecht University, Utrecht, Netherlands
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32
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Nordholt N, van Heerden JH, Bruggeman FJ. Biphasic Cell-Size and Growth-Rate Homeostasis by Single Bacillus subtilis Cells. Curr Biol 2020; 30:2238-2247.e5. [DOI: 10.1016/j.cub.2020.04.030] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 02/19/2020] [Accepted: 04/14/2020] [Indexed: 12/29/2022]
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33
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Dempwolff F, Sanchez S, Kearns DB. Tn FLX: a Third-Generation mariner-Based Transposon System for Bacillus subtilis. Appl Environ Microbiol 2020; 86:e02893-19. [PMID: 32169936 PMCID: PMC7205501 DOI: 10.1128/aem.02893-19] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 01/26/2020] [Indexed: 01/05/2023] Open
Abstract
Random transposon mutagenesis is a powerful and unbiased genetic approach to answer fundamental biological questions. Here, we introduce an improved mariner-based transposon system with enhanced stability during propagation and versatile applications in mutagenesis. We used a low-copy-number plasmid as a transposon delivery vehicle, which affords a lower frequency of unintended recombination during vector construction and propagation in Escherichia coli We generated a variety of transposons allowing for gene disruption or artificial overexpression, each in combination with one of four different antibiotic resistance markers. In addition, we provide transposons that will report gene/protein expression due to transcriptional or translational coupling. We believe that the TnFLX system will help enhance the flexibility of future transposon modification and application in Bacillus and other organisms.IMPORTANCE The stability of transposase-encoding vectors during cloning and propagation is crucial for the reliable application of transposons. Here, we increased the stability of the mariner delivery vehicle in E. coli Moreover, the TnFLX transposon system will improve the application of forward genetic methods with an increased number of antibiotic resistance markers and the ability to generate unbiased green fluorescent protein (GFP) fusions to report on protein translation and subcellular localization.
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Affiliation(s)
- Felix Dempwolff
- Department of Biology, Indiana University, Bloomington, Indiana, USA
| | - Sandra Sanchez
- Department of Biology, Indiana University, Bloomington, Indiana, USA
| | - Daniel B Kearns
- Department of Biology, Indiana University, Bloomington, Indiana, USA
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34
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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: 30] [Impact Index Per Article: 6.0] [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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35
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Competitive Exclusion Is a Major Bioprotective Mechanism of Lactobacilli against Fungal Spoilage in Fermented Milk Products. Appl Environ Microbiol 2020; 86:AEM.02312-19. [PMID: 32005739 PMCID: PMC7082583 DOI: 10.1128/aem.02312-19] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 01/23/2020] [Indexed: 02/07/2023] Open
Abstract
In societies that have food choices, conscious consumers demand natural solutions to keep their food healthy and fresh during storage, simultaneously reducing food waste. The use of “good bacteria” to protect food against spoilage organisms has a long, successful history, even though the molecular mechanisms are not fully understood. In this study, we show that the depletion of free manganese is a major bioprotective mechanism of lactobacilli in dairy products. High manganese uptake and intracellular storage provide a link to the distinct, nonenzymatic, manganese-catalyzed oxidative stress defense mechanism, previously described for certain lactobacilli. The evaluation of representative Lactobacillus species in our study identifies multiple relevant species groups for fungal growth inhibition via manganese depletion. Hence, through the natural mechanism of nutrient depletion, the use of dedicated bioprotective lactobacilli constitutes an attractive alternative to artificial preservation. A prominent feature of lactic acid bacteria (LAB) is their ability to inhibit growth of spoilage organisms in food, but hitherto research efforts to establish the mechanisms underlying bioactivity focused on the production of antimicrobial compounds by LAB. We show, in this study, that competitive exclusion, i.e., competition for a limited resource by different organisms, is a major mechanism of fungal growth inhibition by lactobacilli in fermented dairy products. The depletion of the essential trace element manganese by two Lactobacillus species was uncovered as the main mechanism for growth inhibition of dairy spoilage yeast and molds. A manganese transporter (MntH1), representing one of the highest expressed gene products in both lactobacilli, facilitates the exhaustive manganese scavenging. Expression of the mntH1 gene was found to be strain dependent, affected by species coculturing and the growth phase. Further, deletion of the mntH1 gene in one of the strains resulted in a loss of bioactivity, proving this gene to be important for manganese depletion. The presence of an mntH gene displayed a distinct phylogenetic pattern within the Lactobacillus genus. Moreover, assaying the bioprotective ability in fermented milk of selected lactobacilli from 10 major phylogenetic groups identified a correlation between the presence of mntH and bioprotective activity. Thus, manganese scavenging emerges as a common trait within the Lactobacillus genus, but differences in expression result in some strains showing more bioprotective effect than others. In summary, competitive exclusion through ion depletion is herein reported as a novel mechanism in LAB to delay the growth of spoilage contaminants in dairy products. IMPORTANCE In societies that have food choices, conscious consumers demand natural solutions to keep their food healthy and fresh during storage, simultaneously reducing food waste. The use of “good bacteria” to protect food against spoilage organisms has a long, successful history, even though the molecular mechanisms are not fully understood. In this study, we show that the depletion of free manganese is a major bioprotective mechanism of lactobacilli in dairy products. High manganese uptake and intracellular storage provide a link to the distinct, nonenzymatic, manganese-catalyzed oxidative stress defense mechanism, previously described for certain lactobacilli. The evaluation of representative Lactobacillus species in our study identifies multiple relevant species groups for fungal growth inhibition via manganese depletion. Hence, through the natural mechanism of nutrient depletion, the use of dedicated bioprotective lactobacilli constitutes an attractive alternative to artificial preservation.
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Dysregulation of Magnesium Transport Protects Bacillus subtilis against Manganese and Cobalt Intoxication. J Bacteriol 2020; 202:JB.00711-19. [PMID: 31964700 DOI: 10.1128/jb.00711-19] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 01/16/2020] [Indexed: 12/11/2022] Open
Abstract
Transition metals are essential for life but are toxic when in excess. Metal ion intoxication may result from the mismetallation of essential metal-dependent enzymes with a noncognate metal. To begin to identify enzymes and processes that are susceptible to mismetallation, we have selected for strains with increased resistance to Mn(II) and Co(II). In Bacillus subtilis, cells lacking the MntR metalloregulator are exquisitely sensitive to Mn(II) but can easily become resistant by acquiring mutations affecting the MntH Mn(II) importer. Using transposon mutagenesis, and starting with an mntR mntH strain, we recovered mariner insertions that inactivated the mpfA gene encoding a putative Mg(II) efflux system. Loss of MpfA leads to elevated intracellular Mg(II), increased sensitivity to high Mg(II), and reduced Mn(II) sensitivity. Consistently, we also recovered an insertion disrupting the mgtE riboswitch, which normally restricts expression of the major Mg(II) importer. These results suggest that Mn(II) intoxication results from disruption of a Mg(II)-dependent enzyme or process. Mutations that inactivate MpfA were also recovered in a selection for Co(II) resistance beginning with sensitized strains lacking the major Co(II) efflux pump, CzcD. Since both Mn(II) and Co(II) may mismetallate iron-dependent enzymes, we repeated the selections under conditions of iron depletion imposed by expression of the Listeria monocytogenes FrvA iron exporter. Under conditions of iron depletion, a wider variety of suppressor mutations were recovered, but they still point to a central role for Mg(II) in maintaining metal ion homeostasis.IMPORTANCE Cellular metal ion homeostasis is tightly regulated. When metal ion levels are imbalanced, or when one metal is at toxic levels, enzymes may bind to the wrong metal cofactor. Enzyme mismetallation can impair metabolism, lead to new and deleterious reactions, and cause cell death. Beginning with Bacillus subtilis strains genetically sensitized to metal intoxication through loss of efflux or by lowering intracellular iron, we identified mutations that suppress the deleterious effects of excess Mn(II) or Co(II). For both metals, mutations in mpfA, encoding a Mg(II) efflux pump, suppressed toxicity. These mutant strains have elevated intracellular Mg(II), suggesting that Mg(II)-dependent processes are very sensitive to disruption by transition metals.
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Roles of TroA and TroR in Metalloregulated Growth and Gene Expression in Treponema denticola. J Bacteriol 2020; 202:JB.00770-19. [PMID: 31932313 DOI: 10.1128/jb.00770-19] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 01/03/2020] [Indexed: 02/06/2023] Open
Abstract
The availability of divalent metal cations required as cofactors for microbial metabolism is severely limited in the host environment. Bacteria have evolved highly regulated uptake systems to maintain essential metal homeostasis to meet cellular demands while preventing toxicity. The Tro operon (troABCDR), present in all sequenced Treponema spp., is a member of a highly conserved family of ATP-binding cassette transporters involved in metal cation uptake whose expression is controlled by TroR, a DtxR-like cation-responsive regulatory protein. Transcription of troA responds to divalent manganese and iron (T. denticola) or manganese and zinc (T. pallidum), and metal-dependent TroR binding to the troA promoter represses troA transcription. We report here the construction and complementation of defined T. denticola ΔtroR and ΔtroA strains to characterize (i) the role of TroA in metal-dependent T. denticola growth and (ii) the role of TroR in T. denticola gene expression. We show that TroA expression is required for T. denticola growth under iron- and manganese-limited conditions. Furthermore, TroR is required for the transcriptional regulation of troA in response to iron or manganese, and deletion of troR results in significant differential expression of more than 800 T. denticola genes in addition to troA These results suggest that (i) TroA-mediated cation uptake is important in metal homeostasis in vitro and may be important for Treponema survival in the host environment and (ii) the absence of TroR results in significant dysregulation of nearly one-third of the T. denticola genome. These effects may be direct (as with troA) or indirect due to dysregulation of metal homeostasis.IMPORTANCE Treponema denticola is one of numerous host-associated spirochetes, a group including commensals, pathobionts, and at least one frank pathogen. While most T. denticola research concerns its role in periodontitis, its relative tractability for growth and genetic manipulation make it a useful model for studying Treponema physiology, metabolism, and host-microbe interactions. Metal micronutrient acquisition and homeostasis are highly regulated both in microbial cells and by host innate defense mechanisms that severely limit metal cation bioavailability. Here, we characterized the T. denticola troABCDR operon, the role of TroA-mediated iron and manganese uptake in growth, and the effects of TroR on global gene expression. This study contributes to our understanding of the mechanisms involved in cellular metal homeostasis required for survival in the host environment.
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Cell Membrane and Electron Transfer Engineering for Improved Synthesis of Menaquinone-7 in Bacillus subtilis. iScience 2020; 23:100918. [PMID: 32109677 PMCID: PMC7044751 DOI: 10.1016/j.isci.2020.100918] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 01/09/2020] [Accepted: 02/11/2020] [Indexed: 11/23/2022] Open
Abstract
The formation of biofilm facilitates the synthesis of valuable natural product menaquinone-7 (MK-7) in static culture of Bacillus subtilis, whereas the essential role and mechanism of biofilm in MK-7 synthesis have not been revealed. Herein, comparative transcriptomics show that the formation of biofilm affected MK-7 synthesis by changing the transcription levels of signal receptor (BSU02010), transmembrane transporter (BSU29340, BSU03070), and signal transduction (BSU02630). Moreover, we also found that oxalate decarboxylase OxdC has an important effect on electron generation and MK-7 synthesis, when the transcriptional level of NADH dehydrogenase decreases in static culture. Our results revealed that cell membrane and electron transfer are important factors in promoting MK-7 synthesis. Transcriptome analysis shows the relationship between biofilm and MK-7 synthesis Electron transfer significantly affects the synthesis of MK-7 Oxalate decarboxylase OxdC plays a role in electron generation and MK-7 synthesis
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Bacillus subtilis Regulators MntR and Zur Participate in Redox Cycling, Antibiotic Sensitivity, and Cell Wall Plasticity. J Bacteriol 2020; 202:JB.00547-19. [PMID: 31818924 DOI: 10.1128/jb.00547-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 11/26/2019] [Indexed: 01/03/2023] Open
Abstract
The Bacillus subtilis MntR and Zur transcriptional regulators control homeostasis of manganese and zinc, two essential elements required in various cellular processes. In this work, we describe the global impact of mntR and zur deletions at the protein level. Using a comprehensive proteomic approach, we showed that 33 and 55 proteins are differentially abundant in ΔmntR and Δzur cells, respectively, including proteins involved in metal acquisition, translation, central metabolism, and cell wall homeostasis. In addition, both mutants showed modifications in intracellular metal ion pools, with significant Mg2+ accumulation in the ΔmntR mutant. Phenotypic and morphological analyses of ΔmntR and Δzur mutants revealed their high sensitivity to lysozyme, beta-lactam antibiotics, and external oxidative stress. Mutant strains had a modified cell wall thickness and accumulated lower levels of intracellular reactive oxygen species (ROS) than the wild-type strain. Remarkably, our results highlight an intimate connection between MntR, Zur, antibiotic sensitivity, and cell wall structure.IMPORTANCE Manganese and zinc are essential transition metals involved in many fundamental cellular processes, including protection against external oxidative stress. In Bacillus subtilis, Zur and MntR are key transcriptional regulators of zinc and manganese homeostasis, respectively. In this work, proteome analysis of B. subtilis wild-type, ΔmntR, and Δzur strains provided new insights into bacterial adaptation to deregulation of essential metal ions. Deletions of mntR and zur genes increased bacterial sensitivity to lysozyme, beta-lactam antibiotics, and external oxidative stress and impacted the cell wall thickness. Overall, these findings highlight that Zur and MntR regulatory networks are connected to antibiotic sensitivity and cell wall plasticity.
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Baksh KA, Zamble DB. Allosteric control of metal-responsive transcriptional regulators in bacteria. J Biol Chem 2020; 295:1673-1684. [PMID: 31857375 PMCID: PMC7008368 DOI: 10.1074/jbc.rev119.011444] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Many transition metals are essential trace nutrients for living organisms, but they are also cytotoxic in high concentrations. Bacteria maintain the delicate balance between metal starvation and toxicity through a complex network of metal homeostasis pathways. These systems are coordinated by the activities of metal-responsive transcription factors-also known as metal-sensor proteins or metalloregulators-that are tuned to sense the bioavailability of specific metals in the cell in order to regulate the expression of genes encoding proteins that contribute to metal homeostasis. Metal binding to a metalloregulator allosterically influences its ability to bind specific DNA sequences through a variety of intricate mechanisms that lie on a continuum between large conformational changes and subtle changes in internal dynamics. This review summarizes recent advances in our understanding of how metal sensor proteins respond to intracellular metal concentrations. In particular, we highlight the allosteric mechanisms used for metal-responsive regulation of several prokaryotic single-component metalloregulators, and we briefly discuss current open questions of how metalloregulators function in bacterial cells. Understanding the regulation and function of metal-responsive transcription factors is a fundamental aspect of metallobiochemistry and is important for gaining insights into bacterial growth and virulence.
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Affiliation(s)
- Karina A Baksh
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Deborah B Zamble
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada; Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada.
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Began J, Cordier B, Březinová J, Delisle J, Hexnerová R, Srb P, Rampírová P, Kožíšek M, Baudet M, Couté Y, Galinier A, Veverka V, Doan T, Strisovsky K. Rhomboid intramembrane protease YqgP licenses bacterial membrane protein quality control as adaptor of FtsH AAA protease. EMBO J 2020; 39:e102935. [PMID: 31930742 PMCID: PMC7231995 DOI: 10.15252/embj.2019102935] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 11/18/2019] [Accepted: 12/12/2019] [Indexed: 12/31/2022] Open
Abstract
Magnesium homeostasis is essential for life and depends on magnesium transporters, whose activity and ion selectivity need to be tightly controlled. Rhomboid intramembrane proteases pervade the prokaryotic kingdom, but their functions are largely elusive. Using proteomics, we find that Bacillus subtilis rhomboid protease YqgP interacts with the membrane‐bound ATP‐dependent processive metalloprotease FtsH and cleaves MgtE, the major high‐affinity magnesium transporter in B. subtilis. MgtE cleavage by YqgP is potentiated in conditions of low magnesium and high manganese or zinc, thereby protecting B. subtilis from Mn2+/Zn2+ toxicity. The N‐terminal cytosolic domain of YqgP binds Mn2+ and Zn2+ ions and facilitates MgtE cleavage. Independently of its intrinsic protease activity, YqgP acts as a substrate adaptor for FtsH, a function that is necessary for degradation of MgtE. YqgP thus unites protease and pseudoprotease function, hinting at the evolutionary origin of rhomboid pseudoproteases such as Derlins that are intimately involved in eukaryotic ER‐associated degradation (ERAD). Conceptually, the YqgP‐FtsH system we describe here is analogous to a primordial form of “ERAD” in bacteria and exemplifies an ancestral function of rhomboid‐superfamily proteins.
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Affiliation(s)
- Jakub Began
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Science, Prague, Czech Republic.,Department of Genetics and Microbiology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Baptiste Cordier
- Laboratoire de Chimie Bactérienne (LCB), Institut de Microbiologie de la Méditerranée (IMM), CNRS, UMR 7283, Aix Marseille Univ, Marseille Cedex 20, France
| | - Jana Březinová
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Science, Prague, Czech Republic.,Department of Biochemistry, Faculty of Science, Charles University, Prague, Czech Republic
| | - Jordan Delisle
- Laboratoire de Chimie Bactérienne (LCB), Institut de Microbiologie de la Méditerranée (IMM), CNRS, UMR 7283, Aix Marseille Univ, Marseille Cedex 20, France
| | - Rozálie Hexnerová
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Science, Prague, Czech Republic
| | - Pavel Srb
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Science, Prague, Czech Republic
| | - Petra Rampírová
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Science, Prague, Czech Republic
| | - Milan Kožíšek
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Science, Prague, Czech Republic
| | - Mathieu Baudet
- CEA, Inserm, IRIG-BGE, Univ. Grenoble Alpes, Grenoble, France
| | - Yohann Couté
- CEA, Inserm, IRIG-BGE, Univ. Grenoble Alpes, Grenoble, France
| | - Anne Galinier
- Laboratoire de Chimie Bactérienne (LCB), Institut de Microbiologie de la Méditerranée (IMM), CNRS, UMR 7283, Aix Marseille Univ, Marseille Cedex 20, France
| | - Václav Veverka
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Science, Prague, Czech Republic.,Department of Cell Biology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Thierry Doan
- Laboratoire de Chimie Bactérienne (LCB), Institut de Microbiologie de la Méditerranée (IMM), CNRS, UMR 7283, Aix Marseille Univ, Marseille Cedex 20, France.,Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM), Institut de Microbiologie de la Méditerranée (IMM), CNRS, UMR 7255, Aix Marseille Univ, Marseille Cedex 20, France
| | - Kvido Strisovsky
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Science, Prague, Czech Republic
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Bacillus subtilis TerC Family Proteins Help Prevent Manganese Intoxication. J Bacteriol 2020; 202:JB.00624-19. [PMID: 31685536 DOI: 10.1128/jb.00624-19] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 10/29/2019] [Indexed: 12/24/2022] Open
Abstract
Manganese (Mn) is an essential element and is required for the virulence of many pathogens. In Bacillus subtilis, Mn(II) homeostasis is regulated by MntR, a Mn(II)-responsive, DNA-binding protein. MntR serves as both a repressor of Mn(II) uptake transporters and as a transcriptional activator for expression of two cation diffusion facilitator Mn(II) efflux pumps, MneP and MneS. Mutants lacking either mntR or both mneP and mneS are extremely sensitive to Mn(II) intoxication. Using transposon mutagenesis to select suppressors of Mn(II) sensitivity, we identified YceF, a TerC family membrane protein, as capable of providing Mn(II) resistance. Another TerC paralog, YkoY, is regulated by a Mn(II)-sensing riboswitch and is partially redundant in function with YceF. YkoY is regulated in parallel with an unknown function protein YybP, also controlled by a Mn(II)-sensing riboswitch. Strains lacking between one and five of these known or putative Mn(II) tolerance proteins (MneP, MneS, YceF, YkoY, and YybP) were tested for sensitivity to Mn(II) in growth assays and for accumulation of Mn(II) using inductively coupled plasma mass spectrometry. Loss of YceF and, to a lesser extent, YkoY, sensitizes cells lacking the MneP and MneS efflux transporters to Mn(II) intoxication. This sensitivity correlates with elevated intracellular Mn(II), consistent with the suggestion that TerC proteins function in Mn(II) efflux.IMPORTANCE Manganese homeostasis is primarily regulated at the level of transport. Bacillus subtilis MntR serves as a Mn(II)-activated repressor of importer genes (mntH and mntABC) and an activator of efflux genes (mneP and mneS). Elevated intracellular Mn(II) also binds to Mn-sensing riboswitches to activate transcription of yybP and ykoY, which encodes a TerC family member. Here, we demonstrate that two TerC family proteins, YceF and YkoY, help prevent Mn(II) intoxication. TerC family proteins are widespread in bacteria and may influence host-pathogen interactions, but their effects on Mn(II) homeostasis are unclear. Our results suggest that TerC proteins work by Mn(II) export under Mn(II) overload conditions to help alleviate toxicity.
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Nguyen HTM, Akanuma G, Hoa TTM, Nakai Y, Kimura K, Yamamoto K, Inaoka T. Ribosome Reconstruction during Recovery from High-Hydrostatic-Pressure-Induced Injury in Bacillus subtilis. Appl Environ Microbiol 2019; 86:e01640-19. [PMID: 31604775 PMCID: PMC6912085 DOI: 10.1128/aem.01640-19] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Accepted: 10/03/2019] [Indexed: 02/07/2023] Open
Abstract
Vegetative cells of Bacillus subtilis can recover from injury after high-hydrostatic-pressure (HHP) treatment at 250 MPa. DNA microarray analysis revealed that substantial numbers of ribosomal genes and translation-related genes (e.g., translation initiation factors) were upregulated during the growth arrest phase after HHP treatment. The transcript levels of cold shock-responsive genes, whose products play key roles in efficient translation, and heat shock-responsive genes, whose products mediate correct protein folding or degrade misfolded proteins, were also upregulated. In contrast, the transcript level of hpf, whose product (Hpf) is involved in ribosome inactivation through the dimerization of 70S ribosomes, was downregulated during the growth arrest phase. Sucrose density gradient sedimentation analysis revealed that ribosomes were dissociated in a pressure-dependent manner and then reconstructed. We also found that cell growth after HHP-induced injury was apparently inhibited by the addition of Mn2+ or Zn2+ to the recovery medium. Ribosome reconstruction in the HHP-injured cells was also significantly delayed in the presence of Mn2+ or Zn2+ Moreover, Zn2+, but not Mn2+, promoted dimer formation of 70S ribosomes in the HHP-injured cells. Disruption of the hpf gene suppressed the Zn2+-dependent accumulation of ribosome dimers, partially relieving the inhibitory effect of Zn2+ on the growth recovery of HHP-treated cells. In contrast, it was likely that Mn2+ prevented ribosome reconstruction without stimulating ribosome dimerization. Our results suggested that both Mn2+ and Zn2+ can prevent ribosome reconstruction, thereby delaying the growth recovery of HHP-injured B. subtilis cells.IMPORTANCE HHP treatment is used as a nonthermal processing technology in the food industry to inactivate bacteria while retaining high quality of foods under suppressed chemical reactions. However, some populations of bacterial cells may survive the inactivation. Although the survivors are in a transient nongrowing state due to HHP-induced injury, they can recover from the injury and then start growing, depending on the postprocessing conditions. The recovery process in terms of cellular components after the injury remains unclear. Transcriptome analysis using vegetative cells of Bacillus subtilis revealed that the translational machinery can preferentially be reconstructed after HHP treatment. We found that both Mn2+ and Zn2+ prolonged the growth-arrested stage of HHP-injured cells by delaying ribosome reconstruction. It is likely that ribosome reconstruction is crucial for the recovery of growth ability in HHP-injured cells. This study provides further understanding of the recovery process in HHP-injured B. subtilis cells.
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Affiliation(s)
- Huyen Thi Minh Nguyen
- Food Research Institute, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan
- Institute of Biotechnology, Vietnam Academy of Science and Technology, Ha Noi, Viet Nam
| | | | - Tu Thi Minh Hoa
- Food Research Institute, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan
- Institute of Biotechnology, Vietnam Academy of Science and Technology, Ha Noi, Viet Nam
| | - Yuji Nakai
- Institute of Regional Innovation, Hirosaki University, Aomori, Japan
| | - Keitarou Kimura
- Food Research Institute, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan
| | - Kazutaka Yamamoto
- Food Research Institute, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan
| | - Takashi Inaoka
- Food Research Institute, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan
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Lee MY, Lee DW, Joo HK, Jeong KH, Lee JY. Structural analysis of the manganese transport regulator MntR from Bacillus halodurans in apo and manganese bound forms. PLoS One 2019; 14:e0224689. [PMID: 31738781 PMCID: PMC6860424 DOI: 10.1371/journal.pone.0224689] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 10/18/2019] [Indexed: 01/05/2023] Open
Abstract
The manganese transport regulator MntR is a metal-ion activated transcriptional repressor of manganese transporter genes to maintain manganese ion homeostasis. MntR, a member of the diphtheria toxin repressor (DtxR) family of metalloregulators, selectively responds to Mn2+ and Cd2+ over Fe2+, Co2+ and Zn2+. The DtxR/MntR family members are well conserved transcriptional repressors that regulate the expression of metal ion uptake genes by sensing the metal ion concentration. MntR functions as a homo-dimer with one metal ion binding site per subunit. Each MntR subunit contains two domains: an N-terminal DNA binding domain, and a C-terminal dimerization domain. However, it lacks the C-terminal SH3-like domain of DtxR/IdeR. The metal ion binding site of MntR is located at the interface of the two domains, whereas the DtxR/IdeR subunit contains two metal ion binding sites, the primary and ancillary sites, separated by 9 Å. In this paper, we reported the crystal structures of the apo and Mn2+-bound forms of MntR from Bacillus halodurans, and analyze the structural basis of the metal ion binding site. The crystal structure of the Mn2+-bound form is almost identical to the apo form of MntR. In the Mn2+-bound structure, one subunit contains a binuclear cluster of manganese ions, the A and C sites, but the other subunit forms a mononuclear complex. Structural data about MntR from B. halodurans supports the previous hypothesizes about manganese-specific activation mechanism of MntR homologues.
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Affiliation(s)
- Myeong Yeon Lee
- Department of Life Science, Dongguk University-Seoul, Ilsandong-gu, Goyang-si, Gyeonggi-do, Republic of Korea
| | - Dong Won Lee
- Department of Life Science, Dongguk University-Seoul, Ilsandong-gu, Goyang-si, Gyeonggi-do, Republic of Korea
| | - Hyun Kyu Joo
- Department of Life Science, Dongguk University-Seoul, Ilsandong-gu, Goyang-si, Gyeonggi-do, Republic of Korea
| | - Kang Hwa Jeong
- Department of Life Science, Dongguk University-Seoul, Ilsandong-gu, Goyang-si, Gyeonggi-do, Republic of Korea
| | - Jae Young Lee
- Department of Life Science, Dongguk University-Seoul, Ilsandong-gu, Goyang-si, Gyeonggi-do, Republic of Korea
- * E-mail:
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Huang Z, Wu L, Li X, Ma L, Borriss R, Gao X. Zn(II) suppresses biofilm formation in Bacillus amyloliquefaciens by inactivation of the Mn(II) uptake. Environ Microbiol 2019; 22:1547-1558. [PMID: 31715659 DOI: 10.1111/1462-2920.14859] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 11/08/2019] [Accepted: 11/10/2019] [Indexed: 11/29/2022]
Abstract
Biofilms are architecturally complex communities of microbial cells held together by a self-produced extracellular matrix. Considerable research has focused on the environmental signals that trigger or inhibit biofilm formation by affecting cellular signalling pathways; however, response to soil cues in plant-associated Bacillus has remained largely unaddressed. Therefore, we aimed to investigate the effect of Zn(II) ions in biofilm formation of Bacillus amyloliquefaciens FZB42. We demonstrated that the biofilm formation of B. amyloliquefaciens FZB42 was abolished by Zn(II) at non-deleterious concentrations. Moreover, Zn(II) blocked matrix exopolysaccharide and TasA accumulations. Furthermore, the presence of Zn(II) suppressed expression of the response regulator Spo0F but not of sensor histidine kinases KinA-D. Suppression of phosphorelay by excess Zn interferes with sinI induction under biofilm-inducing conditions, leading to repression of transcription of operons epsA-O and tapA-sigW-tasA. Addition of Zn(II) decreased the intracellular Mn(II) level by competing for binding to the solute-binding protein MntA during Mn(II) uptake. These results suggest that the metal ion Zn(II) has a negative effect on biofilm formation in the plant growth promoting and biocontrol bacterium B. amyloliquefaciens FZB42.
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Affiliation(s)
- Ziyang Huang
- College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Disease and Pest Insects, Ministry of Education, Nanjing, 210095, China
| | - Liming Wu
- College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Disease and Pest Insects, Ministry of Education, Nanjing, 210095, China
| | - Xi Li
- College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Disease and Pest Insects, Ministry of Education, Nanjing, 210095, China
| | - Liumin Ma
- College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Disease and Pest Insects, Ministry of Education, Nanjing, 210095, China
| | - Rainer Borriss
- Nord Reet UG, Greifswald, Germany.,Fachgebiet Phytomedizin, Institut für Agrar- und Gartenbauwissenschaften, Humboldt Universität, Berlin, Germany
| | - Xuewen Gao
- College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Disease and Pest Insects, Ministry of Education, Nanjing, 210095, China
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46
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Schult F, Le TN, Albersmeier A, Rauch B, Blumenkamp P, van der Does C, Goesmann A, Kalinowski J, Albers SV, Siebers B. Effect of UV irradiation on Sulfolobus acidocaldarius and involvement of the general transcription factor TFB3 in the early UV response. Nucleic Acids Res 2019; 46:7179-7192. [PMID: 29982548 PMCID: PMC6101591 DOI: 10.1093/nar/gky527] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 05/30/2018] [Indexed: 12/19/2022] Open
Abstract
Exposure to UV light can result in severe DNA damage. The alternative general transcription factor (GTF) TFB3 has been proposed to play a key role in the UV stress response in the thermoacidophilic crenarchaeon Sulfolobus acidocaldarius. Reporter gene assays confirmed that tfb3 is upregulated 90–180 min after UV treatment. In vivo tagging and immunodetection of TFB3 confirmed the induced expression at 90 min. Analysis of a tfb3 insertion mutant showed that genes encoding proteins of the Ups pili and the Ced DNA importer are no longer induced in a tfb3 insertion mutant after UV treatment, which was confirmed by aggregation assays. Thus, TFB3 plays a crucial role in the activation of these genes. Genome wide transcriptome analysis allowed a differentiation between a TFB3-dependent and a TFB3-independent early UV response. The TFB3-dependent UV response is characterized by the early induction of TFB3, followed by TFB3-dependent expression of genes involved in e.g. Ups pili formation and the Ced DNA importer. Many genes were downregulated in the tfb3 insertion mutant confirming the hypothesis that TFB3 acts as an activator of transcription. The TFB3-independent UV response includes the repression of nucleotide metabolism, replication and cell cycle progression in order to allow DNA repair.
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Affiliation(s)
- Frank Schult
- Molecular Enzyme Technology and Biochemistry (MEB), Biofilm Centre, Centre for Water and Environmental Research (CWE), Faculty of Chemistry, University of Duisburg-Essen, Universitätsstraße 5, 45141 Essen, Germany
| | - Thuong N Le
- Institute of Biology II, Molecular Biology of Archaea, University of Freiburg, Schaenzlestraße 1, 79104 Freiburg, Germany
| | - Andreas Albersmeier
- Center for Biotechnology (CEBITEC), University of Bielefeld, Universitätsstraße 25, 33615 Bielefeld, Germany
| | - Bernadette Rauch
- Molecular Enzyme Technology and Biochemistry (MEB), Biofilm Centre, Centre for Water and Environmental Research (CWE), Faculty of Chemistry, University of Duisburg-Essen, Universitätsstraße 5, 45141 Essen, Germany
| | - Patrick Blumenkamp
- Institute for Bioinformatics and Systems Biology, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 58, 35392 Giessen, Germany
| | - Chris van der Does
- Institute of Biology II, Molecular Biology of Archaea, University of Freiburg, Schaenzlestraße 1, 79104 Freiburg, Germany
| | - Alexander Goesmann
- Institute for Bioinformatics and Systems Biology, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 58, 35392 Giessen, Germany
| | - Jörn Kalinowski
- Center for Biotechnology (CEBITEC), University of Bielefeld, Universitätsstraße 25, 33615 Bielefeld, Germany
| | - Sonja-Verena Albers
- Institute of Biology II, Molecular Biology of Archaea, University of Freiburg, Schaenzlestraße 1, 79104 Freiburg, Germany
| | - Bettina Siebers
- Molecular Enzyme Technology and Biochemistry (MEB), Biofilm Centre, Centre for Water and Environmental Research (CWE), Faculty of Chemistry, University of Duisburg-Essen, Universitätsstraße 5, 45141 Essen, Germany
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47
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Párraga Solórzano PK, Yao J, Rock CO, Kehl-Fie TE. Disruption of Glycolysis by Nutritional Immunity Activates a Two-Component System That Coordinates a Metabolic and Antihost Response by Staphylococcus aureus. mBio 2019; 10:e01321-19. [PMID: 31387906 PMCID: PMC6686040 DOI: 10.1128/mbio.01321-19] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 07/09/2019] [Indexed: 02/01/2023] Open
Abstract
During infection, bacteria use two-component signal transduction systems to sense and adapt to the dynamic host environment. Despite critically contributing to infection, the activating signals of most of these regulators remain unknown. This also applies to the Staphylococcus aureus ArlRS two-component system, which contributes to virulence by coordinating the production of toxins, adhesins, and a metabolic response that enables the bacterium to overcome host-imposed manganese starvation. Restricting the availability of essential transition metals, a strategy known as nutritional immunity, constitutes a critical defense against infection. In this work, expression analysis revealed that manganese starvation imposed by the immune effector calprotectin or by the absence of glycolytic substrates activates ArlRS. Manganese starvation imposed by calprotectin also activated the ArlRS system even when glycolytic substrates were present. A combination of metabolomics, mutational analysis, and metabolic feeding experiments revealed that ArlRS is activated by alterations in metabolic flux occurring in the latter half of the glycolytic pathway. Moreover, calprotectin was found to induce expression of staphylococcal leukocidins in an ArlRS-dependent manner. These studies indicated that ArlRS is a metabolic sensor that allows S. aureus to integrate multiple environmental stresses that alter glycolytic flux to coordinate an antihost response and to adapt to manganese starvation. They also established that the latter half of glycolysis represents a checkpoint to monitor metabolic state in S. aureus Altogether, these findings contribute to understanding how invading pathogens, such as S. aureus, adapt to the host during infection and suggest the existence of similar mechanisms in other bacterial species.IMPORTANCE Two-component regulatory systems enable bacteria to adapt to changes in their environment during infection by altering gene expression and coordinating antihost responses. Despite the critical role of two-component systems in bacterial survival and pathogenesis, the activating signals for most of these regulators remain unidentified. This is exemplified by ArlRS, a Staphylococcus aureus global regulator that contributes to virulence and to resisting host-mediated restriction of essential nutrients, such as manganese. In this report, we demonstrate that manganese starvation and the absence of glycolytic substrates activate ArlRS. Further investigations revealed that ArlRS is activated when the latter half of glycolysis is disrupted, suggesting that S. aureus monitors flux through the second half of this pathway. Host-imposed manganese starvation also induced the expression of pore-forming toxins in an ArlRS-dependent manner. Cumulatively, this work reveals that ArlRS acts as a sensor that links nutritional status, cellular metabolism, and virulence regulation.
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Affiliation(s)
- Paola K Párraga Solórzano
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Departmento de Ciencias de la Vida, Universidad de las Fuerzas Armadas ESPE, Sangolquí, Ecuador
| | - Jiangwei Yao
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Charles O Rock
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Thomas E Kehl-Fie
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
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48
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Martin JE, Le MT, Bhattarai N, Capdevila DA, Shen J, Winkler ME, Giedroc DP. A Mn-sensing riboswitch activates expression of a Mn2+/Ca2+ ATPase transporter in Streptococcus. Nucleic Acids Res 2019; 47:6885-6899. [PMID: 31165873 PMCID: PMC6649816 DOI: 10.1093/nar/gkz494] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 05/08/2019] [Accepted: 05/31/2019] [Indexed: 12/27/2022] Open
Abstract
Maintaining manganese (Mn) homeostasis is important for the virulence of numerous bacteria. In the human respiratory pathogen Streptococcus pneumoniae, the Mn-specific importer PsaBCA, exporter MntE, and transcriptional regulator PsaR establish Mn homeostasis. In other bacteria, Mn homeostasis is controlled by yybP-ykoY family riboswitches. Here, we characterize a yybP-ykoY family riboswitch upstream of the mgtA gene encoding a PII-type ATPase in S. pneumoniae, suggested previously to function in Ca2+ efflux. We show that the mgtA riboswitch aptamer domain adopts a canonical yybP-ykoY structure containing a three-way junction that is compacted in the presence of Ca2+ or Mn2+ at a physiological Mg2+ concentration. Although Ca2+ binds to the RNA aptamer with higher affinity than Mn2+, in vitro activation of transcription read-through of mgtA by Mn2+ is much greater than by Ca2+. Consistent with this result, mgtA mRNA and protein levels increase ≈5-fold during cellular Mn stress, but only in genetic backgrounds of S. pneumoniae and Bacillus subtilis that exhibit Mn2+ sensitivity, revealing that this riboswitch functions as a failsafe 'on' signal to prevent Mn2+ toxicity in the presence of high cellular Mn2+. In addition, our results suggest that the S. pneumoniae yybP-ykoY riboswitch functions to regulate Ca2+ efflux under these conditions.
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Affiliation(s)
- Julia E Martin
- Department of Biological Sciences, Idaho State University, Pocatello, ID 83209, USA
| | - My T Le
- Department of Cell Biology, Faculty of Biological Sciences, Vietnam National University, Hanoi, Vietnam
| | - Nabin Bhattarai
- Department of Biological Sciences, Idaho State University, Pocatello, ID 83209, USA
| | | | - Jiangchuan Shen
- Department of Cellular and Molecular Biochemistry, Indiana University, Bloomington, IN 47405, USA
| | - Malcolm E Winkler
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - David P Giedroc
- Department of Chemistry, Indiana University, Bloomington, IN 47405, USA
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49
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Osman D, Martini MA, Foster AW, Chen J, Scott AJP, Morton RJ, Steed JW, Lurie-Luke E, Huggins TG, Lawrence AD, Deery E, Warren MJ, Chivers PT, Robinson NJ. Bacterial sensors define intracellular free energies for correct enzyme metalation. Nat Chem Biol 2019; 15:241-249. [PMID: 30692683 PMCID: PMC6420079 DOI: 10.1038/s41589-018-0211-4] [Citation(s) in RCA: 113] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 12/04/2018] [Indexed: 01/06/2023]
Abstract
There is a challenge for metalloenzymes to acquire their correct metals because some inorganic elements form more stable complexes with proteins than do others. These preferences can be overcome provided some metals are more available than others. However, while the total amount of cellular metal can be readily measured, the available levels of each metal have been more difficult to define. Metal-sensing transcriptional regulators are tuned to the intracellular availabilities of their cognate ions. Here we have determined the standard free energy for metal complex formation to which each sensor, in a set of bacterial metal sensors, is attuned: The less competitive the metal, the less favorable the free energy and hence greater availability to which the cognate allosteric mechanism is tuned. Comparing these free energies with values derived from the metal affinities of a metalloprotein reveals the mechanism of correct metalation exemplified here by a cobalt-chelatase for vitamin B12.
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Affiliation(s)
- Deenah Osman
- Department of Biosciences, Durham University, Durham, UK.,Department of Chemistry, Durham University, Durham, UK
| | | | - Andrew W Foster
- Department of Biosciences, Durham University, Durham, UK.,Department of Chemistry, Durham University, Durham, UK
| | - Junjun Chen
- Procter and Gamble, Mason Business Center, Cincinnati, OH, USA
| | | | - Richard J Morton
- Department of Mathematics, Physics and Electrical Engineering, Northumbria University, Newcastle-upon-Tyne, UK
| | | | | | | | | | - Evelyne Deery
- School of Biosciences, University of Kent, Canterbury, Kent, UK
| | - Martin J Warren
- School of Biosciences, University of Kent, Canterbury, Kent, UK
| | - Peter T Chivers
- Department of Biosciences, Durham University, Durham, UK. .,Department of Chemistry, Durham University, Durham, UK.
| | - Nigel J Robinson
- Department of Biosciences, Durham University, Durham, UK. .,Department of Chemistry, Durham University, Durham, UK.
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50
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Radin JN, Zhu J, Brazel EB, McDevitt CA, Kehl-Fie TE. Synergy between Nutritional Immunity and Independent Host Defenses Contributes to the Importance of the MntABC Manganese Transporter during Staphylococcus aureus Infection. Infect Immun 2019; 87:e00642-18. [PMID: 30348827 PMCID: PMC6300641 DOI: 10.1128/iai.00642-18] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 10/16/2018] [Indexed: 12/14/2022] Open
Abstract
During infection, the host utilizes a diverse array of processes to combat invaders, including the restriction of availability of essential nutrients such as manganese. Similarly to many other pathogens, Staphylococcus aureus possesses two manganese importers, MntH and MntABC. Several infection models have revealed a critical role for MntABC during staphylococcal infection. However, culture-based studies have suggested parity between the two transporters when cells are resisting manganese starvation imposed by the manganese binding immune effector calprotectin. In this investigation, initial elemental analysis revealed that MntABC is the primary transporter responsible for obtaining manganese in culture in the presence of calprotectin. MntABC was also necessary to maintain wild-type levels of manganese-dependent superoxide dismutase activity in the presence of calprotectin. Building on this framework, we investigated if MntABC enabled S. aureus to resist the synergistic actions of nutritional immunity and other host defenses. This analysis revealed that MntABC critically contributes to staphylococcal growth when S. aureus is subjected to manganese limitations and exposed to oxidative stress. This transporter was also important for growth in manganese-limited environments when S. aureus was forced to consume glucose as an energy source, which occurs when it encounters nitric oxide. MntABC also expanded the pH range conducive for S. aureus growth under conditions of manganese scarcity. Collectively, the data presented in this work provide a robust molecular basis for the crucial role of MntABC in staphylococcal virulence. Further, this work highlights the importance of synergy between host defenses and the necessity of evaluating the contribution of virulence factors to pathogenesis in the presence of multiple stressors.
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Affiliation(s)
- Jana N Radin
- Department of Microbiology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Jamie Zhu
- Department of Microbiology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Erin B Brazel
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia
| | - Christopher A McDevitt
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - Thomas E Kehl-Fie
- Department of Microbiology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
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