1
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Williams TJ, Allen MA, Ray AE, Benaud N, Chelliah DS, Albanese D, Donati C, Selbmann L, Coleine C, Ferrari BC. Novel endolithic bacteria of phylum Chloroflexota reveal a myriad of potential survival strategies in the Antarctic desert. Appl Environ Microbiol 2024; 90:e0226423. [PMID: 38372512 PMCID: PMC10952385 DOI: 10.1128/aem.02264-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Accepted: 01/02/2024] [Indexed: 02/20/2024] Open
Abstract
The ice-free McMurdo Dry Valleys of Antarctica are dominated by nutrient-poor mineral soil and rocky outcrops. The principal habitat for microorganisms is within rocks (endolithic). In this environment, microorganisms are provided with protection against sub-zero temperatures, rapid thermal fluctuations, extreme dryness, and ultraviolet and solar radiation. Endolithic communities include lichen, algae, fungi, and a diverse array of bacteria. Chloroflexota is among the most abundant bacterial phyla present in these communities. Among the Chloroflexota are four novel classes of bacteria, here named Candidatus Spiritibacteria class. nov. (=UBA5177), Candidatus Martimicrobia class. nov. (=UBA4733), Candidatus Tarhunnaeia class. nov. (=UBA6077), and Candidatus Uliximicrobia class. nov. (=UBA2235). We retrieved 17 high-quality metagenome-assembled genomes (MAGs) that represent these four classes. Based on genome predictions, all these bacteria are inferred to be aerobic heterotrophs that encode enzymes for the catabolism of diverse sugars. These and other organic substrates are likely derived from lichen, algae, and fungi, as metabolites (including photosynthate), cell wall components, and extracellular matrix components. The majority of MAGs encode the capacity for trace gas oxidation using high-affinity uptake hydrogenases, which could provide energy and metabolic water required for survival and persistence. Furthermore, some MAGs encode the capacity to couple the energy generated from H2 and CO oxidation to support carbon fixation (atmospheric chemosynthesis). All encode mechanisms for the detoxification and efflux of heavy metals. Certain MAGs encode features that indicate possible interactions with other organisms, such as Tc-type toxin complexes, hemolysins, and macroglobulins.IMPORTANCEThe ice-free McMurdo Dry Valleys of Antarctica are the coldest and most hyperarid desert on Earth. It is, therefore, the closest analog to the surface of the planet Mars. Bacteria and other microorganisms survive by inhabiting airspaces within rocks (endolithic). We identify four novel classes of phylum Chloroflexota, and, based on interrogation of 17 metagenome-assembled genomes, we predict specific metabolic and physiological adaptations that facilitate the survival of these bacteria in this harsh environment-including oxidation of trace gases and the utilization of nutrients (including sugars) derived from lichen, algae, and fungi. We propose that such adaptations allow these endolithic bacteria to eke out an existence in this cold and extremely dry habitat.
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Affiliation(s)
- Timothy J. Williams
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales, Australia
| | - Michelle A. Allen
- School of Biological, Earth and Environmental Sciences, UNSW Sydney, Sydney, New South Wales, Australia
| | - Angelique E. Ray
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales, Australia
| | - Nicole Benaud
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales, Australia
| | - Devan S. Chelliah
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales, Australia
| | - Davide Albanese
- Research and Innovation Center, Fondazione Edmund Mach, San Michele all’Adige, Italy
| | - Claudio Donati
- Research and Innovation Center, Fondazione Edmund Mach, San Michele all’Adige, Italy
| | - Laura Selbmann
- Department of Ecological and Biological Sciences, University of Tuscia, Largo dell’Università, Viterbo, Italy
- Mycological Section, Italian Antarctic National Museum (MNA), Genova, Italy
| | - Claudia Coleine
- Department of Ecological and Biological Sciences, University of Tuscia, Largo dell’Università, Viterbo, Italy
| | - Belinda C. Ferrari
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales, Australia
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2
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Volarić J, van der Heide NJ, Mutter NL, Samplonius DF, Helfrich W, Maglia G, Szymanski W, Feringa BL. Visible Light Control over the Cytolytic Activity of a Toxic Pore-Forming Protein. ACS Chem Biol 2024; 19:451-461. [PMID: 38318850 PMCID: PMC10877574 DOI: 10.1021/acschembio.3c00640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 01/16/2024] [Accepted: 01/17/2024] [Indexed: 02/07/2024]
Abstract
Enabling control over the bioactivity of proteins with light, along with the principles of photopharmacology, has the potential to generate safe and targeted medical treatments. Installing light sensitivity in a protein can be achieved through its covalent modification with a molecular photoswitch. The general challenge in this approach is the need for the use of low energy visible light for the regulation of bioactivity. In this study, we report visible light control over the cytolytic activity of a protein. A water-soluble visible-light-operated tetra-ortho-fluoro-azobenzene photoswitch was synthesized by utilizing the nucleophilic aromatic substitution reaction for installing a solubilizing sulfonate group onto the electron-poor photoswitch structure. The azobenzene was attached to two cysteine mutants of the pore-forming protein fragaceatoxin C (FraC), and their respective activities were evaluated on red blood cells. For both mutants, the green-light-irradiated sample, containing predominantly the cis-azobenzene isomer, was more active compared to the blue-light-irradiated sample. Ultimately, the same modulation of the cytolytic activity pattern was observed toward a hypopharyngeal squamous cell carcinoma. These results constitute the first case of using low energy visible light to control the biological activity of a toxic protein.
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Affiliation(s)
- Jana Volarić
- Stratingh
Institute for Organic Chemistry, University
of Groningen, 9747 AG Groningen, The Netherlands
| | - Nieck J. van der Heide
- Groningen
Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Natalie L. Mutter
- Groningen
Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Douwe F. Samplonius
- Department
of Surgery, Translational Surgical Oncology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands
| | - Wijnand Helfrich
- Department
of Surgery, Translational Surgical Oncology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands
| | - Giovanni Maglia
- Groningen
Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Wiktor Szymanski
- Stratingh
Institute for Organic Chemistry, University
of Groningen, 9747 AG Groningen, The Netherlands
- Department
of Radiology, Medical Imaging Center, University
of Groningen, University Medical Center Groningen, 9713 GZ Groningen, The Netherlands
| | - Ben L. Feringa
- Stratingh
Institute for Organic Chemistry, University
of Groningen, 9747 AG Groningen, The Netherlands
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3
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Feldmüller M, Ericson CF, Afanasyev P, Lien YW, Weiss GL, Wollweber F, Schoof M, Hurst M, Pilhofer M. Stepwise assembly and release of Tc toxins from Yersinia entomophaga. Nat Microbiol 2024; 9:405-420. [PMID: 38316932 PMCID: PMC10847046 DOI: 10.1038/s41564-024-01611-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 01/17/2024] [Indexed: 02/07/2024]
Abstract
Tc toxins are virulence factors of bacterial pathogens. Although their structure and intoxication mechanism are well understood, it remains elusive where this large macromolecular complex is assembled and how it is released. Here we show by an integrative multiscale imaging approach that Yersinia entomophaga Tc (YenTc) toxin components are expressed only in a subpopulation of cells that are 'primed' with several other potential virulence factors, including filaments of the protease M66/StcE. A phage-like lysis cassette is required for YenTc release; however, before resulting in complete cell lysis, the lysis cassette generates intermediate 'ghost' cells, which may serve as assembly compartments and become packed with assembled YenTc holotoxins. We hypothesize that this stepwise mechanism evolved to minimize the number of cells that need to be killed. The occurrence of similar lysis cassettes in diverse organisms indicates a conserved mechanism for Tc toxin release that may apply to other extracellular macromolecular machines.
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Affiliation(s)
- Miki Feldmüller
- Department of Biology, Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule Zürich, Zürich, Switzerland
| | - Charles F Ericson
- Department of Biology, Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule Zürich, Zürich, Switzerland
| | | | - Yun-Wei Lien
- Department of Biology, Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule Zürich, Zürich, Switzerland
| | - Gregor L Weiss
- Department of Biology, Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule Zürich, Zürich, Switzerland
| | - Florian Wollweber
- Department of Biology, Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule Zürich, Zürich, Switzerland
| | - Marion Schoof
- Bio-Protection Research Centre, Lincoln University, Lincoln, Christchurch, New Zealand
- AgResearch, Resilient Agriculture, Lincoln Research Centre, Christchurch, New Zealand
| | - Mark Hurst
- Bio-Protection Research Centre, Lincoln University, Lincoln, Christchurch, New Zealand
- AgResearch, Resilient Agriculture, Lincoln Research Centre, Christchurch, New Zealand
| | - Martin Pilhofer
- Department of Biology, Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule Zürich, Zürich, Switzerland.
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4
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Sitsel O, Wang Z, Janning P, Kroczek L, Wagner T, Raunser S. Yersinia entomophaga Tc toxin is released by T10SS-dependent lysis of specialized cell subpopulations. Nat Microbiol 2024; 9:390-404. [PMID: 38238469 PMCID: PMC10847048 DOI: 10.1038/s41564-023-01571-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 11/29/2023] [Indexed: 02/04/2024]
Abstract
Disease-causing bacteria secrete numerous toxins to invade and subjugate their hosts. Unlike many smaller toxins, the secretion machinery of most large toxins remains enigmatic. By combining genomic editing, proteomic profiling and cryo-electron tomography of the insect pathogen Yersinia entomophaga, we demonstrate that a specialized subset of these cells produces a complex toxin cocktail, including the nearly ribosome-sized Tc toxin YenTc, which is subsequently exported by controlled cell lysis using a transcriptionally coupled, pH-dependent type 10 secretion system (T10SS). Our results dissect the Tc toxin export process by a T10SS, identifying that T10SSs operate via a previously unknown lytic mode of action and establishing them as crucial players in the size-insensitive release of cytoplasmically folded toxins. With T10SSs directly embedded in Tc toxin operons of major pathogens, we anticipate that our findings may model an important aspect of pathogenesis in bacteria with substantial impact on agriculture and healthcare.
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Affiliation(s)
- Oleg Sitsel
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Zhexin Wang
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Petra Janning
- Department of Chemical Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Lara Kroczek
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Thorsten Wagner
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Stefan Raunser
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany.
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5
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Martin CL, Chester DW, Radka CD, Pan L, Yang Z, Hart RC, Binshtein EM, Wang Z, Nagy L, DeLucas LJ, Aller SG. Structures of the Insecticidal Toxin Complex Subunit XptA2 Highlight Roles for Flexible Domains. Int J Mol Sci 2023; 24:13221. [PMID: 37686027 PMCID: PMC10487846 DOI: 10.3390/ijms241713221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 08/18/2023] [Accepted: 08/20/2023] [Indexed: 09/10/2023] Open
Abstract
The Toxin Complex (Tc) superfamily consists of toxin translocases that contribute to the targeting, delivery, and cytotoxicity of certain pathogenic Gram-negative bacteria. Membrane receptor targeting is driven by the A-subunit (TcA), which comprises IgG-like receptor binding domains (RBDs) at the surface. To better understand XptA2, an insect specific TcA secreted by the symbiont X. nematophilus from the intestine of entomopathogenic nematodes, we determined structures by X-ray crystallography and cryo-EM. Contrary to a previous report, XptA2 is pentameric. RBD-B exhibits an indentation from crystal packing that indicates loose association with the shell and a hotspot for possible receptor binding or a trigger for conformational dynamics. A two-fragment XptA2 lacking an intact linker achieved the folded pre-pore state like wild type (wt), revealing no requirement of the linker for protein folding. The linker is disordered in all structures, and we propose it plays a role in dynamics downstream of the initial pre-pore state.
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Affiliation(s)
- Cole L. Martin
- Department of Pharmacology & Toxicology, University of Alabama at Birmingham, Birmingham, AL 35205, USA; (C.L.M.); (D.W.C.); (C.D.R.); (L.P.)
| | - David W. Chester
- Department of Pharmacology & Toxicology, University of Alabama at Birmingham, Birmingham, AL 35205, USA; (C.L.M.); (D.W.C.); (C.D.R.); (L.P.)
| | - Christopher D. Radka
- Department of Pharmacology & Toxicology, University of Alabama at Birmingham, Birmingham, AL 35205, USA; (C.L.M.); (D.W.C.); (C.D.R.); (L.P.)
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky, Lexington, KY 40536, USA
| | - Lurong Pan
- Department of Pharmacology & Toxicology, University of Alabama at Birmingham, Birmingham, AL 35205, USA; (C.L.M.); (D.W.C.); (C.D.R.); (L.P.)
| | - Zhengrong Yang
- Department of Biochemistry & Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL 35205, USA;
| | - Rachel C. Hart
- Department of Pathology, Microbiology & Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; (R.C.H.); (E.M.B.)
| | - Elad M. Binshtein
- Department of Pathology, Microbiology & Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; (R.C.H.); (E.M.B.)
| | - Zhao Wang
- Biochemistry & Molecular Pharmacology, Cryo-Electron Microscopy and Tomography Core, Baylor College of Medicine, Houston, TX 77030, USA;
| | - Lisa Nagy
- Department of Mathematics, Engineering & Physical Sciences, Jefferson State Community College, Jefferson Campus, Birmingham, AL 35215, USA;
| | - Lawrence J. DeLucas
- Predictive Oncology Inc., 200 Riverhills Business Park, Suite 250, Birmingham, AL 35242, USA;
| | - Stephen G. Aller
- Department of Pharmacology & Toxicology, University of Alabama at Birmingham, Birmingham, AL 35205, USA; (C.L.M.); (D.W.C.); (C.D.R.); (L.P.)
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6
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Tian S, Zhou N. Gaining New Insights into Fundamental Biological Pathways by Bacterial Toxin-Based Genetic Screens. Bioengineering (Basel) 2023; 10:884. [PMID: 37627769 PMCID: PMC10451959 DOI: 10.3390/bioengineering10080884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 07/11/2023] [Accepted: 07/22/2023] [Indexed: 08/27/2023] Open
Abstract
Genetic screen technology has been applied to study the mechanism of action of bacterial toxins-a special class of virulence factors that contribute to the pathogenesis caused by bacterial infections. These screens aim to identify host factors that directly or indirectly facilitate toxin intoxication. Additionally, specific properties of certain toxins, such as membrane interaction, retrograde trafficking, and carbohydrate binding, provide robust probes to comprehensively investigate the lipid biosynthesis, membrane vesicle transport, and glycosylation pathways, respectively. This review specifically focuses on recent representative toxin-based genetic screens that have identified new players involved in and provided new insights into fundamental biological pathways, such as glycosphingolipid biosynthesis, protein glycosylation, and membrane vesicle trafficking pathways. Functionally characterizing these newly identified factors not only expands our current understanding of toxin biology but also enables a deeper comprehension of fundamental biological questions. Consequently, it stimulates the development of new therapeutic approaches targeting both bacterial infectious diseases and genetic disorders with defects in these factors and pathways.
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Affiliation(s)
- Songhai Tian
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Beijing 100191, China
- Department of Urology, Boston Children’s Hospital, Boston, MA 02115, USA;
- Department of Microbiology and Department of Surgery, Harvard Medical School, Boston, MA 02115, USA
| | - Nini Zhou
- Department of Urology, Boston Children’s Hospital, Boston, MA 02115, USA;
- Department of Microbiology and Department of Surgery, Harvard Medical School, Boston, MA 02115, USA
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7
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Pacheco S, Gómez I, Peláez-Aguilar AE, Verduzco-Rosas LA, García-Suárez R, do Nascimento NA, Rivera-Nájera LY, Cantón PE, Soberón M, Bravo A. Structural changes upon membrane insertion of the insecticidal pore-forming toxins produced by Bacillus thuringiensis. Front Insect Sci 2023; 3:1188891. [PMID: 38469496 PMCID: PMC10926538 DOI: 10.3389/finsc.2023.1188891] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Accepted: 04/04/2023] [Indexed: 03/13/2024]
Abstract
Different Bacillus thuringiensis (Bt) strains produce a broad variety of pore-forming toxins (PFTs) that show toxicity against insects and other invertebrates. Some of these insecticidal PFT proteins have been used successfully worldwide to control diverse insect crop pests. There are several studies focused on describing the mechanism of action of these toxins that have helped to improve their performance and to cope with the resistance evolved by different insects against some of these proteins. However, crucial information that is still missing is the structure of pores formed by some of these PFTs, such as the three-domain crystal (Cry) proteins, which are the most commercially used Bt toxins in the biological control of insect pests. In recent years, progress has been made on the identification of the structural changes that certain Bt insecticidal PFT proteins undergo upon membrane insertion. In this review, we describe the models that have been proposed for the membrane insertion of Cry toxins. We also review the recently published structures of the vegetative insecticidal proteins (Vips; e.g. Vip3) and the insecticidal toxin complex (Tc) in the membrane-inserted state. Although different Bt PFTs show different primary sequences, there are some similarities in the three-dimensional structures of Vips and Cry proteins. In addition, all PFTs described here must undergo major structural rearrangements to pass from a soluble form to a membrane-inserted state. It is proposed that, despite their structural differences, all PFTs undergo major structural rearrangements producing an extended α-helix, which plays a fundamental role in perforating their target membrane, resulting in the formation of the membrane pore required for their insecticidal activity.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Alejandra Bravo
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
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8
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Harvey DJ. Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: An update for 2019-2020. Mass Spectrom Rev 2022:e21806. [PMID: 36468275 DOI: 10.1002/mas.21806] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
This review is the tenth update of the original article published in 1999 on the application of matrix-assisted laser desorption/ionization (MALDI) mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2020. Also included are papers that describe methods appropriate to analysis by MALDI, such as sample preparation techniques, even though the ionization method is not MALDI. The review is basically divided into three sections: (1) general aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, fragmentation, quantification and the use of arrays. (2) Applications to various structural types such as oligo- and polysaccharides, glycoproteins, glycolipids, glycosides and biopharmaceuticals, and (3) other areas such as medicine, industrial processes and glycan synthesis where MALDI is extensively used. Much of the material relating to applications is presented in tabular form. The reported work shows increasing use of incorporation of new techniques such as ion mobility and the enormous impact that MALDI imaging is having. MALDI, although invented nearly 40 years ago is still an ideal technique for carbohydrate analysis and advancements in the technique and range of applications show little sign of diminishing.
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Affiliation(s)
- David J Harvey
- Nuffield Department of Medicine, Target Discovery Institute, University of Oxford, Oxford, UK
- Department of Chemistry, University of Oxford, Oxford, Oxfordshire, United Kingdom
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9
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Sänger PA, Wagner S, Liebler-Tenorio EM, Fuchs TM. Dissecting the invasion of Galleria mellonella by Yersinia enterocolitica reveals metabolic adaptations and a role of a phage lysis cassette in insect killing. PLoS Pathog 2022; 18:e1010991. [PMID: 36399504 PMCID: PMC9718411 DOI: 10.1371/journal.ppat.1010991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 12/02/2022] [Accepted: 11/08/2022] [Indexed: 11/19/2022] Open
Abstract
The human pathogen Yersinia enterocolitica strain W22703 is characterized by its toxicity towards invertebrates that requires the insecticidal toxin complex (Tc) proteins encoded by the pathogenicity island Tc-PAIYe. Molecular and pathophysiological details of insect larvae infection and killing by this pathogen, however, have not been dissected. Here, we applied oral infection of Galleria mellonella (Greater wax moth) larvae to study the colonisation, proliferation, tissue invasion, and killing activity of W22703. We demonstrated that this strain is strongly toxic towards the larvae, in which they proliferate by more than three orders of magnitude within six days post infection. Deletion mutants of the genes tcaA and tccC were atoxic for the insect. W22703 ΔtccC, in contrast to W22703 ΔtcaA, initially proliferated before being eliminated from the host, thus confirming TcaA as membrane-binding Tc subunit and TccC as cell toxin. Time course experiments revealed a Tc-dependent infection process starting with midgut colonisation that is followed by invasion of the hemolymph where the pathogen elicits morphological changes of hemocytes and strongly proliferates. The in vivo transcriptome of strain W22703 shows that the pathogen undergoes a drastic reprogramming of central cell functions and gains access to numerous carbohydrate and amino acid resources within the insect. Strikingly, a mutant lacking a phage-related holin/endolysin (HE) cassette, which is located within Tc-PAIYe, resembled the phenotypes of W22703 ΔtcaA, suggesting that this dual lysis cassette may be an example of a phage-related function that has been adapted for the release of a bacterial toxin.
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Affiliation(s)
| | - Stefanie Wagner
- Friedrich-Loeffler-Institut, Institut für Molekulare Pathogenese, Jena, Germany
| | | | - Thilo M. Fuchs
- Friedrich-Loeffler-Institut, Institut für Molekulare Pathogenese, Jena, Germany
- * E-mail:
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10
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Xu Y, Viswanatha R, Sitsel O, Roderer D, Zhao H, Ashwood C, Voelcker C, Tian S, Raunser S, Perrimon N, Dong M. CRISPR screens in Drosophila cells identify Vsg as a Tc toxin receptor. Nature 2022; 610:349-55. [PMID: 36171290 DOI: 10.1038/s41586-022-05250-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 08/18/2022] [Indexed: 11/08/2022]
Abstract
Entomopathogenic nematodes are widely used as biopesticides1,2. Their insecticidal activity depends on symbiotic bacteria such as Photorhabdus luminescens, which produces toxin complex (Tc) toxins as major virulence factors3-6. No protein receptors are known for any Tc toxins, which limits our understanding of their specificity and pathogenesis. Here we use genome-wide CRISPR-Cas9-mediated knockout screening in Drosophila melanogaster S2R+ cells and identify Visgun (Vsg) as a receptor for an archetypal P. luminescens Tc toxin (pTc). The toxin recognizes the extracellular O-glycosylated mucin-like domain of Vsg that contains high-density repeats of proline, threonine and serine (HD-PTS). Vsg orthologues in mosquitoes and beetles contain HD-PTS and can function as pTc receptors, whereas orthologues without HD-PTS, such as moth and human versions, are not pTc receptors. Vsg is expressed in immune cells, including haemocytes and fat body cells. Haemocytes from Vsg knockout Drosophila are resistant to pTc and maintain phagocytosis in the presence of pTc, and their sensitivity to pTc is restored through the transgenic expression of mosquito Vsg. Last, Vsg knockout Drosophila show reduced bacterial loads and lethality from P. luminescens infection. Our findings identify a proteinaceous Tc toxin receptor, reveal how Tc toxins contribute to P. luminescens pathogenesis, and establish a genome-wide CRISPR screening approach for investigating insecticidal toxins and pathogens.
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11
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Abstract
Through their specific interactions with proteins, cellular glycans play key roles in a wide range of physiological and pathological processes. One of the main goals of research in the areas of glycobiology and glycomedicine is to understand glycan-protein interactions at the molecular level. Over the past two decades, glycan microarrays have become powerful tools for the rapid evaluation of interactions between glycans and proteins. In this review, we briefly describe methods used for the preparation of glycan probes and the construction of glycan microarrays. Next, we highlight applications of glycan microarrays to rapid profiling of glycan-binding patterns of plant, animal and pathogenic lectins, as well as other proteins. Finally, we discuss other important uses of glycan microarrays, including the rapid analysis of substrate specificities of carbohydrate-active enzymes, the quantitative determination of glycan-protein interactions, discovering high-affinity or selective ligands for lectins, and identifying functional glycans within cells. We anticipate that this review will encourage researchers to employ glycan microarrays in diverse glycan-related studies.
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Affiliation(s)
- Yujun Kim
- Department of Chemistry, Yonsei University, 03722 Seoul, Republic of Korea.
| | - Ji Young Hyun
- Department of Drug Discovery, Data Convergence Drug Research Center, Korea Research Institute of Chemical Technology (KRICT), Daejeon 34114, Republic of Korea.
| | - Injae Shin
- Department of Chemistry, Yonsei University, 03722 Seoul, Republic of Korea.
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12
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Belyy A, Lindemann F, Roderer D, Funk J, Bardiaux B, Protze J, Bieling P, Oschkinat H, Raunser S. Mechanism of threonine ADP-ribosylation of F-actin by a Tc toxin. Nat Commun 2022; 13:4202. [PMID: 35858890 PMCID: PMC9300711 DOI: 10.1038/s41467-022-31836-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 07/01/2022] [Indexed: 11/25/2022] Open
Abstract
Tc toxins deliver toxic enzymes into host cells by a unique injection mechanism. One of these enzymes is the actin ADP-ribosyltransferase TccC3, whose activity leads to the clustering of the cellular cytoskeleton and ultimately cell death. Here, we show in atomic detail how TccC3 modifies actin. We find that the ADP-ribosyltransferase does not bind to G-actin but interacts with two consecutive actin subunits of F-actin. The binding of TccC3 to F-actin occurs via an induced-fit mechanism that facilitates access of NAD+ to the nucleotide binding pocket. The following nucleophilic substitution reaction results in the transfer of ADP-ribose to threonine-148 of F-actin. We demonstrate that this site-specific modification of F-actin prevents its interaction with depolymerization factors, such as cofilin, which impairs actin network turnover and leads to steady actin polymerization. Our findings reveal in atomic detail a mechanism of action of a bacterial toxin through specific targeting and modification of F-actin. Entomopathogenic bacteria used for pest control secrete potent Tc toxins. Here, the authors combine biochemistry, solution and solid-state NMR spectroscopy and cryo-EM to show in atomic detail how the toxin disrupts the host cell cytoskeleton and kills the target cell.
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Affiliation(s)
- Alexander Belyy
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Otto-Hahn-Str. 11, 44227, Dortmund, Germany
| | - Florian Lindemann
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert-Rössle-Str. 10, 13125, Berlin, Germany
| | - Daniel Roderer
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Otto-Hahn-Str. 11, 44227, Dortmund, Germany.,Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert-Rössle-Str. 10, 13125, Berlin, Germany
| | - Johanna Funk
- Department of Systemic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Str. 11, 44227, Dortmund, Germany
| | - Benjamin Bardiaux
- Institut Pasteur, Université Paris Cité, CNRS UMR3528, Structural Bioinformatics Unit, 25-28 Rue du Docteur Roux, F-75015, Paris, France
| | - Jonas Protze
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert-Rössle-Str. 10, 13125, Berlin, Germany
| | - Peter Bieling
- Department of Systemic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Str. 11, 44227, Dortmund, Germany
| | - Hartmut Oschkinat
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert-Rössle-Str. 10, 13125, Berlin, Germany.
| | - Stefan Raunser
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Otto-Hahn-Str. 11, 44227, Dortmund, Germany.
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Lee S, Inzerillo S, Lee GY, Bosire EM, Mahato SK, Song J. Glycan-mediated molecular interactions in bacterial pathogenesis. Trends Microbiol 2022; 30:254-67. [PMID: 34274195 DOI: 10.1016/j.tim.2021.06.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 06/10/2021] [Accepted: 06/22/2021] [Indexed: 02/06/2023]
Abstract
Glycans are expressed on the surface of nearly all host and bacterial cells. Not surprisingly, glycan-mediated molecular interactions play a vital role in bacterial pathogenesis and host responses against pathogens. Glycan-mediated host-pathogen interactions can benefit the pathogen, host, or both. Here, we discuss (i) bacterial glycans that play a critical role in bacterial colonization and/or immune evasion, (ii) host glycans that are utilized by bacteria for pathogenesis, and (iii) bacterial and host glycans involved in immune responses against pathogens. We further discuss (iv) opportunities and challenges for transforming these research findings into more effective antibacterial strategies, and (v) technological advances in glycoscience that have helped to accelerate progress in research. These studies collectively offer valuable insights into new perspectives on antibacterial strategies that may effectively tackle the drug-resistant pathogens that are rapidly spreading globally.
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14
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Benton JT, Bayly-Jones C. Challenges and approaches to studying pore-forming proteins. Biochem Soc Trans 2021:BST20210706. [PMID: 34747994 DOI: 10.1042/BST20210706] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 09/19/2021] [Accepted: 10/06/2021] [Indexed: 02/07/2023]
Abstract
Pore-forming proteins (PFPs) are a broad class of molecules that comprise various families, structural folds, and assembly pathways. In nature, PFPs are most often deployed by their host organisms to defend against other organisms. In humans, this is apparent in the immune system, where several immune effectors possess pore-forming activity. Furthermore, applications of PFPs are found in next-generation low-cost DNA sequencing, agricultural crop protection, pest control, and biosensing. The advent of cryoEM has propelled the field forward. Nevertheless, significant challenges and knowledge-gaps remain. Overcoming these challenges is particularly important for the development of custom, purpose-engineered PFPs with novel or desired properties. Emerging single-molecule techniques and methods are helping to address these unanswered questions. Here we review the current challenges, problems, and approaches to studying PFPs.
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15
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Ng'ang'a PN, Siukstaite L, Lang AE, Bakker H, Römer W, Aktories K, Schmidt G. Involvement of N-glycans in binding of Photorhabdus luminescens Tc toxin. Cell Microbiol 2021; 23:e13326. [PMID: 33720490 DOI: 10.1111/cmi.13326] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 03/09/2021] [Accepted: 03/10/2021] [Indexed: 12/20/2022]
Abstract
Photorhabdus luminescens Tc toxins are large tripartite ABC-type toxin complexes, composed of TcA, TcB and TcC proteins. Tc toxins are widespread and have shown a tropism for a variety of targets including insect, mammalian and human cells. However, their receptors and the specific mechanisms of uptake into target cells remain unknown. Here, we show that the TcA protein TcdA1 interacts with N-glycans, particularly Lewis X/Y antigens. This is confirmed using N-acetylglucosamine transferase I (Mgat1 gene product)-deficient Chinese hamster ovary (CHO) Lec1 cells, which are highly resistant to intoxication by the Tc toxin complex most likely due to the absence of complex N-glycans. Restoring Mgat1 gene activity, and hence complex N-glycan biosynthesis, recapitulated the sensitivity of these cells to the toxin. Exogenous addition of Lewis X trisaccharide partially inhibits intoxication in wild-type cells. Additionally, sialic acid also largely reduced binding of the Tc toxin. Moreover, proteolytic activation of TcdA1 alters glycan-binding and uptake into target cells. The data suggest that TcdA1-binding is most likely multivalent, and carbohydrates probably work cooperatively to facilitate binding and intoxication.
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Affiliation(s)
- Peter Njenga Ng'ang'a
- Institute for Experimental and Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Spemann Graduate School for Biology and Medicine, University of Freiburg, Freiburg, Germany
| | - Lina Siukstaite
- Faculty of Biology, University of Freiburg, Freiburg, Germany.,CIBSS-Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Alexander E Lang
- Institute for Experimental and Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Hans Bakker
- Institut für Klinische Biochemie, Medizinische Hochschule Hannover, MHH, Hannover, Germany
| | - Winfried Römer
- Spemann Graduate School for Biology and Medicine, University of Freiburg, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany.,CIBSS-Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany.,BIOSS-Centre for Biological Signaling Studies, University of Freiburg, Freiburg, Germany
| | - Klaus Aktories
- Institute for Experimental and Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Spemann Graduate School for Biology and Medicine, University of Freiburg, Freiburg, Germany.,BIOSS-Centre for Biological Signaling Studies, University of Freiburg, Freiburg, Germany
| | - Gudula Schmidt
- Institute for Experimental and Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
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16
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Abstract
Electron microscopy has consistently played an important role in the description of pore-forming protein systems. The discovery of pore-forming proteins has depended on visualization of the structural pores formed by their oligomeric protein complexes, and as electron microscopy has advanced technologically so has the degree of insight it has been able to give. This review considers a large number of published studies of pore-forming complexes in prepore and pore states determined using single-particle cryo-electron microscopy. Sample isolation and preparation, imaging and image analysis, structure determination and optimization of results are all discussed alongside challenges which pore-forming proteins particularly present. The review also considers the use made of cryo-electron tomography to study pores within their membrane environment and which will prove an increasingly important approach for the future.
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Affiliation(s)
- Robert J C Gilbert
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom.
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17
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Song N, Chen L, Ren X, Waterfield NR, Yang J, Yang G. N-Glycans and sulfated glycosaminoglycans contribute to the action of diverse Tc toxins on mammalian cells. PLoS Pathog 2021; 17:e1009244. [PMID: 33539469 PMCID: PMC7861375 DOI: 10.1371/journal.ppat.1009244] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 12/18/2020] [Indexed: 01/11/2023] Open
Abstract
Tc toxin is an exotoxin composed of three subunits named TcA, TcB and TcC. Structural analysis revealed that TcA can form homopentamer that mediates the cellular recognition and delivery processes, thus contributing to the host tropism of Tc toxin. N-glycans and heparan sulfates have been shown to act as receptors for several Tc toxins. Here, we performed two independent genome-wide CRISPR-Cas9 screens, and have validated glycans and sulfated glycosaminoglycans (sGAGs) as Tc toxin receptors also for previously uncharacterized Tc toxins. We found that TcdA1 form Photorhabdus luminescens W14 (TcdA1W14) can recognize N-glycans via the RBD-D domain, corroborating previous findings. Knockout of N-glycan processing enzymes specifically blocks the intoxication of TcdA1W14-assembled Tc toxin. On the other hand, our results showed that sGAG biosynthesis pathway is involved in the cell surface binding of TcdA2TT01 (TcdA2 from P. luminescens TT01). Competition assays and biolayer interferometry demonstrated that the sulfation group in sGAGs is required for the binding of TcdA2TT01. Finally, based on the conserved domains of representative TcA proteins, we have identified 1,189 putative TcAs from 1,039 bacterial genomes. These TcAs are categorized into five subfamilies. Each subfamily shows a good correlation with both genetic organization of the TcA protein(s) and taxonomic origin of the genomes, suggesting these subfamilies may utilize different mechanisms for cellular recognition. Taken together, our results support the previously described two different binding modalities of Tc toxins, leading to unique host targeting properties. We also present the bioinformatics data and receptor screening strategies for TcA proteins, provide new insights into understanding host specificity and biomedical applications of Tc toxins. The Toxin complexes, also referred to as Tc toxins, are a family of A5BC exotoxins widely distributed among Gram-negative and positive bacteria. First identified in Entomopathogenic bacteria as key virulence factors to combat insect hosts, putative Tc toxin loci are also encoded by a range of human pathogens such as Salmonella and Yersinia. Previous studies indicated that several Tc toxins can target invertebrate and vertebrate cells via binding with N-glycans and heparan sulfates. Here our genome-wide CRISPR-Cas9 screens validated that different Tc toxins utilized distinct receptors for the adhesion to their targets, which is determined by TcA homopentamer. For example, TcdA1 from Photorhabdus luminescens W14 (TcdA1W14) relies on N-glycan binding to exert its toxic effects, while sulfate groups of sulfated glycosaminoglycans are critical for the cell targeting of other TcAs such as TcdA2TT01 (TcdA2 from P. luminescens TT01). Consistent with the previously described different binding modalities of Tc toxins, our results confirm that the receptor selectivity of TcAs contribute to the cellular tropism of Tc toxins. Furthermore we has also identified 1,189 TcA homologues and categorized them into five subfamilies. Each TcA subfamily shows a good correlation with the taxonomic origin of the genomes, suggesting these subfamilies are linked to diverse host tropisms via different binding modalities. Together, our findings provide mechanistic insights into understanding host specificity of distinct Tc toxins and the development of therapeutics for Tc toxin-related infections, as well as the adaptation of Tc-injectisomes as potential biotechnology tools and pest-control weapons.
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Affiliation(s)
- Nan Song
- Beijing Institute of Tropical Medicine, Beijing Friendship Hospital, Capital Medical University, Beijing, China
- Emergency and Critical Care Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Lihong Chen
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xingmei Ren
- Beijing Institute of Tropical Medicine, Beijing Friendship Hospital, Capital Medical University, Beijing, China
- Emergency and Critical Care Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | | | - Jian Yang
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Guowei Yang
- Beijing Institute of Tropical Medicine, Beijing Friendship Hospital, Capital Medical University, Beijing, China
- Emergency and Critical Care Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China
- * E-mail:
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