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Prajapati A, Hemanth RA, Namrutha MR, Bindu S, Yogisharadhya R, Mohanty NN, Chanda MM, Shivachandra SB. Production of highly soluble and immuno-reactive recombinant flagellin protein of Clostridium chauvoei. Anaerobe 2024; 89:102899. [PMID: 39142535 DOI: 10.1016/j.anaerobe.2024.102899] [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: 04/08/2024] [Revised: 06/02/2024] [Accepted: 08/10/2024] [Indexed: 08/16/2024]
Abstract
OBJECTIVE Flagellin protein, an integral component of flagella, provides motility to several bacterial species and also acts as a candidate antigen in diagnostics and subunit vaccines. The bulk production of flagellin with retention of all conformational epitopes using recombinant protein technology is of paramount importance in the development of pathogen-specific immuno-assays and vaccines. We describe the production of highly soluble and immuno-reactive rFliA(C) protein of Clostridium chauvoei, a causative agent of blackleg or black quarter (BQ) affecting cattle and small ruminants worldwide. The bacterium is known to possess peritrichous flagella that provide motility and also act as a virulence factor with high protective antigenicity. METHODS Upon sequence and structural analysis, a partial fliA(C) gene from Clostridium chauvoei was cloned and the recombinant mature protein with N- and C- terminal truncation was over-expressed as a His-tagged fusion protein (∼25 kDa) in Escherichia coli. Subsequently, rFliA(C) protein was purified by single-step affinity chromatography and characterized for its immuno-reactivity in laboratory animals, Western blot, and indirect-ELISA format. RESULTS rFliA(C) was highly soluble and was purified in high quantity and quality. rFliA(C) elicited antigen-specific conformational polyclonal antibodies in rabbit and guinea pig models, as well as anti-Clostridium chauvoei-specific antibodies being specifically detected in BQ-vaccinated and convalescent sera of bovines in Western blot and in indirect-ELISA format. Further, no cross reactivity was noted with antibodies against major bovine diseases (e.g., foot-and-mouth disease, IBR, LSDV, hemorrhagic septicaemia, brucellosis, and leptospirosis). CONCLUSION The study indicated the production of conformational recombinant flagellin-rFliA(C)-antigen and its potential utility in development of diagnostics for detection of Clostridium chauvoei-specific antibodies in BQ-recovered and/or vaccinated animals.
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Affiliation(s)
- Awadhesh Prajapati
- ICAR-National Institute of Veterinary Epidemiology and Disease Informatics (NIVEDI), Post Box No. 6450, Yelahanka, Bengaluru, 560064, Karnataka, India
| | - Roopa Anandamurthy Hemanth
- ICAR-National Institute of Veterinary Epidemiology and Disease Informatics (NIVEDI), Post Box No. 6450, Yelahanka, Bengaluru, 560064, Karnataka, India
| | - Mandira Ramakrishna Namrutha
- ICAR-National Institute of Veterinary Epidemiology and Disease Informatics (NIVEDI), Post Box No. 6450, Yelahanka, Bengaluru, 560064, Karnataka, India
| | - Suresh Bindu
- ICAR-National Institute of Veterinary Epidemiology and Disease Informatics (NIVEDI), Post Box No. 6450, Yelahanka, Bengaluru, 560064, Karnataka, India
| | - Revanaiah Yogisharadhya
- ICAR-Krishi Vigyan Kendra (KVK), ICAR-Research Complex for NEH Region, Hailakandi, 788152, Assam, India
| | - Nihar Nalini Mohanty
- CCS-National Institute of Animal Health (NIAH), Baghpat, 250609, Uttar Pradesh (UP), India
| | - Mohammed Mudassar Chanda
- ICAR-National Institute of Veterinary Epidemiology and Disease Informatics (NIVEDI), Post Box No. 6450, Yelahanka, Bengaluru, 560064, Karnataka, India
| | - Sathish Bhadravati Shivachandra
- ICAR-National Institute of Veterinary Epidemiology and Disease Informatics (NIVEDI), Post Box No. 6450, Yelahanka, Bengaluru, 560064, Karnataka, India.
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Roh H, Kannimuthu D. Genomic and Transcriptomic Diversification of Flagellin Genes Provides Insight into Environmental Adaptation and Phylogeographic Characteristics in Aeromonas hydrophila. MICROBIAL ECOLOGY 2024; 87:65. [PMID: 38695873 PMCID: PMC11065939 DOI: 10.1007/s00248-024-02373-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Accepted: 04/01/2024] [Indexed: 05/05/2024]
Abstract
Aeromonas hydrophila is an opportunistic motile pathogen with a broad host range, infecting both terrestrial and aquatic animals. Environmental and geographical conditions exert selective pressure on both geno- and phenotypes of pathogens. Flagellin, directly exposed to external environments and containing important immunogenic epitopes, may display significant variability in response to external conditions. In this study, we conducted a comparative analysis of ~ 150 A. hydrophila genomes, leading to the identification of six subunits of the flagellin gene (fla-1 to fla-4, flaA, and flaB). Individual strains harbored different composition of flagellin subunits and copies. The composition of subunits showed distinct patterns depending on environmental sources. Strains from aquatic environments were mainly comprised of fla-1 to fla-4 subunits, while terrestrial strains predominated in groups harboring flaA and flaB subunits. Each flagellin showed varying levels of expression, with flaA and flaB demonstrating significantly higher expression compared to others. One of the chemotaxis pathways that control flagellin movement through a two-component system was significantly upregulated in flaA(+ 1)/flaB(+ 1) group, whereas flaA and flaB showed different transcriptomic expressions. The genes positively correlated with flaA expression were relevant to biofilm formation and bacterial chemotaxis, but flaB showed a negative correlation with the genes in ABC transporters and quorum sensing pathway. However, the expression patterns of fla-2 to fla-4 were identical. This suggests various types of flagellin subunits may have different biological functions. The composition and expression levels of flagellin subunits could provide valuable insights into the adaptation of A. hydrophila and the differences among strains in response to various external environments.
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Affiliation(s)
- HyeongJin Roh
- Pathogen Transmission and Disease Research Group, Institute of Marine Research, PO Box 1870 Nordnes 5870, Bergen, Norway.
| | - Dhamotharan Kannimuthu
- Pathogen Transmission and Disease Research Group, Institute of Marine Research, PO Box 1870 Nordnes 5870, Bergen, Norway
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3
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Kemter AM, Patry RT, Arnold J, Hesser LA, Campbell E, Ionescu E, Mimee M, Wang S, Nagler CR. Commensal bacteria signal through TLR5 and AhR to improve barrier integrity and prevent allergic responses to food. Cell Rep 2023; 42:113153. [PMID: 37742185 PMCID: PMC10697505 DOI: 10.1016/j.celrep.2023.113153] [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: 11/30/2022] [Revised: 08/07/2023] [Accepted: 09/01/2023] [Indexed: 09/26/2023] Open
Abstract
The increasing prevalence of food allergies has been linked to reduced commensal microbial diversity. In this article, we describe two features of allergy-protective Clostridia that contribute to their beneficial effects. Some Clostridial taxa bear flagella (a ligand for TLR5) and produce indole (a ligand for the aryl hydrocarbon receptor [AhR]). Lysates and flagella from a Clostridia consortium induced interleukin-22 (IL-22) secretion from ileal explants. IL-22 production is abrogated in explants from mice in which TLR5 or MyD88 signaling is deficient either globally or conditionally in CD11c+ antigen-presenting cells. AhR signaling in RORγt+ cells is necessary for the induction of IL-22. Mice deficient in AhR in RORγt+ cells exhibit increased intestinal permeability and are more susceptible to an anaphylactic response to food. Our findings implicate TLR5 and AhR signaling in a molecular mechanism by which commensal Clostridia protect against allergic responses to food.
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Affiliation(s)
- Andrea M Kemter
- Department of Pathology, The University of Chicago, Chicago, IL 60637, USA
| | - Robert T Patry
- Department of Pathology, The University of Chicago, Chicago, IL 60637, USA
| | - Jack Arnold
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, IL 60637, USA
| | - Lauren A Hesser
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, IL 60637, USA
| | - Evelyn Campbell
- Committee on Microbiology, The University of Chicago, Chicago, IL 60637, USA
| | - Edward Ionescu
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, IL 60637, USA
| | - Mark Mimee
- Department of Microbiology, The University of Chicago, Chicago, IL 60637, USA; Pritzker School of Molecular Engineering, The University of Chicago, Chicago, IL 60637, USA; Committee on Microbiology, The University of Chicago, Chicago, IL 60637, USA
| | - Shan Wang
- Department of Pathology, The University of Chicago, Chicago, IL 60637, USA
| | - Cathryn R Nagler
- Department of Pathology, The University of Chicago, Chicago, IL 60637, USA; Pritzker School of Molecular Engineering, The University of Chicago, Chicago, IL 60637, USA; Committee on Immunology, The University of Chicago, Chicago, IL 60637, USA.
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4
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Clasen SJ, Bell MEW, Borbón A, Lee DH, Henseler ZM, de la Cuesta-Zuluaga J, Parys K, Zou J, Wang Y, Altmannova V, Youngblut ND, Weir JR, Gewirtz AT, Belkhadir Y, Ley RE. Silent recognition of flagellins from human gut commensal bacteria by Toll-like receptor 5. Sci Immunol 2023; 8:eabq7001. [PMID: 36608151 DOI: 10.1126/sciimmunol.abq7001] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Flagellin, the protein subunit of the bacterial flagellum, stimulates the innate immune receptor Toll-like receptor 5 (TLR5) after pattern recognition or evades TLR5 through lack of recognition. This binary response fails to explain the weak agonism of flagellins from commensal bacteria, raising the question of how TLR5 response is tuned. Here, we screened abundant flagellins present in metagenomes from human gut for both TLR5 recognition and activation and uncovered a class of flagellin-TLR5 interaction termed silent recognition. Silent flagellins were weak TLR5 agonists despite pattern recognition. Receptor activity was tuned by a TLR5-flagellin interaction distal to the site of pattern recognition that was present in Salmonella flagellin but absent in silent flagellins. This interaction enabled flagellin binding to preformed TLR5 dimers and increased TLR5 signaling by several orders of magnitude. Silent recognition by TLR5 occurred in human organoids and mice, and silent flagellin proteins were present in human stool. These flagellins were produced primarily by the abundant gut bacteria Lachnospiraceae and were enriched in nonindustrialized populations. Our findings provide a mechanism for the innate immune system to tolerate commensal-derived flagellins while remaining vigilant to the presence of flagellins produced by pathogens.
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Affiliation(s)
- Sara J Clasen
- Department of Microbiome Science, Max Planck Institute for Biology, Tübingen 72076, Germany
| | - Michael E W Bell
- Department of Microbiome Science, Max Planck Institute for Biology, Tübingen 72076, Germany
| | - Andrea Borbón
- Department of Microbiome Science, Max Planck Institute for Biology, Tübingen 72076, Germany
| | - Du-Hwa Lee
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC), Dr. Bohr-Gasse 3, Vienna, Austria
| | - Zachariah M Henseler
- Department of Microbiome Science, Max Planck Institute for Biology, Tübingen 72076, Germany
| | | | - Katarzyna Parys
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC), Dr. Bohr-Gasse 3, Vienna, Austria
| | - Jun Zou
- Center for Inflammation, Immunity and Infection, Institute for Biomedical Sciences, Georgia State University, Atlanta, GA, USA
| | - Yanling Wang
- Center for Inflammation, Immunity and Infection, Institute for Biomedical Sciences, Georgia State University, Atlanta, GA, USA
| | - Veronika Altmannova
- Friedrich Miescher Laboratory of the Max Planck Society, Max-Planck-Ring 9, Tübingen 72076, Germany
| | - Nicholas D Youngblut
- Department of Microbiome Science, Max Planck Institute for Biology, Tübingen 72076, Germany
| | - John R Weir
- Friedrich Miescher Laboratory of the Max Planck Society, Max-Planck-Ring 9, Tübingen 72076, Germany
| | - Andrew T Gewirtz
- Center for Inflammation, Immunity and Infection, Institute for Biomedical Sciences, Georgia State University, Atlanta, GA, USA
| | - Youssef Belkhadir
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC), Dr. Bohr-Gasse 3, Vienna, Austria
| | - Ruth E Ley
- Department of Microbiome Science, Max Planck Institute for Biology, Tübingen 72076, Germany.,Cluster of Excellence EXC 2124 Controlling Microbes to Fight Infections, University of Tübingen, Tübingen, Germany
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5
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Involvement of Flagellin in Kin Recognition between Bacillus velezensis Strains. mSystems 2022; 7:e0077822. [PMID: 36218362 PMCID: PMC9764977 DOI: 10.1128/msystems.00778-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Kin discrimination in nature is an effective way for bacteria to stabilize population cooperation and maintain progeny benefits. However, so far, the research on kin discrimination for Bacillus still has concentrated on "attack and defense" between cells and diffusion-dependent molecular signals of quorum sensing, kin recognition in Bacillus, however, has not been reported. To determine whether flagellar is involve in the kin recognition of Bacillus, we constructed Bacillus velezensis SQR9 assembled with flagellin of its kin and non-kin strains, and performed a swarm boundary assay with SQR9, then analyzed sequence variation of flagellin and other flagellar structural proteins in B. velezensis genus. Our results showed that SQR9 assembled with flagellin of non-kin strains was more likely to form a border phenotype with wild-type strain SQR9 in swarm assay than that of kin strains, and that non-kin strains had greater variation in flagellin than kin strains. In B. velezensis, these variations in flagellin were prevalent and had evolved significantly faster than other flagellar structural proteins. Therefore, we proposed that flagellin is an effective tool partly involved in the kin recognition of B. velezensis strains. IMPORTANCE Kin selection plays an important role in stabilizing population cooperation and maintaining the progeny benefits for bacteria in nature. However, to date, the role of flagellin in kin recognition in Bacillus has not been reported. By using rhizospheric Bacillus velezensis SQR9, we accomplished flagellin region interchange among its related strains, and show that flagellin acts as a mediator to distinguish kin from non-kin in B. velezensis. We demonstrated the polymorphism of flagellin in B. velezensis through alignment analysis of flagellin protein sequences. Therefore, it was proposed that flagellin was likely to be an effective tool for mediating kin recognition in B. velezensis.
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Mondino S, San Martin F, Buschiazzo A. 3D cryo-electron microscopic imaging of bacterial flagella: novel structural and mechanistic insights into cell motility. J Biol Chem 2022; 298:102105. [PMID: 35671822 PMCID: PMC9254593 DOI: 10.1016/j.jbc.2022.102105] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 05/28/2022] [Accepted: 05/30/2022] [Indexed: 10/26/2022] Open
Abstract
Bacterial flagella are nanomachines that enable cells to move at high speeds. Comprising ≳25 different types of proteins, the flagellum is a large supramolecular assembly organized into three widely conserved substructures: a basal body including the rotary motor, a connecting hook, and a long filament. The whole flagellum from Escherichia coli weighs ∼20 MDa, without considering its filament portion, which is by itself a ∼1.6 GDa structure arranged as a multimer of ∼30,000 flagellin protomers. Breakthroughs regarding flagellar structure and function have been achieved in the last few years, mainly due to the revolutionary improvements in 3D cryo-electron microscopy methods. This review discusses novel structures and mechanistic insights derived from such high-resolution studies, advancing our understanding of each one of the three major flagellar segments. The rotation mechanism of the motor has been unveiled with unprecedented detail, showing a two-cogwheel machine propelled by a Brownian ratchet device. Additionally, by imaging the flagellin-like protomers that make up the hook in its native bent configuration, their unexpected conformational plasticity challenges the paradigm of a two-state conformational rearrangement mechanism for flagellin-fold proteins. Finally, imaging of the filaments of periplasmic flagella, which endow Spirochete bacteria with their singular motility style, uncovered a strikingly asymmetric protein sheath that coats the flagellin core, challenging the view of filaments as simple homopolymeric structures that work as freely whirling whips. Further research will shed more light on the functional details of this amazing nanomachine, but our current understanding has definitely come a long way.
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Affiliation(s)
- Sonia Mondino
- Laboratory of Molecular & Structural Microbiology, Institut Pasteur de Montevideo, Montevideo, Uruguay; Integrative Microbiology of Zoonotic Agents IMiZA Unit, Joint International Unit, Institut Pasteur/Institut Pasteur de Montevideo, France/Uruguay
| | - Fabiana San Martin
- Laboratory of Molecular & Structural Microbiology, Institut Pasteur de Montevideo, Montevideo, Uruguay; Integrative Microbiology of Zoonotic Agents IMiZA Unit, Joint International Unit, Institut Pasteur/Institut Pasteur de Montevideo, France/Uruguay
| | - Alejandro Buschiazzo
- Laboratory of Molecular & Structural Microbiology, Institut Pasteur de Montevideo, Montevideo, Uruguay; Integrative Microbiology of Zoonotic Agents IMiZA Unit, Joint International Unit, Institut Pasteur/Institut Pasteur de Montevideo, France/Uruguay; Microbiology Department, Institut Pasteur, Paris, France.
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7
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Hu D, Fuller NR, Caterson ID, Holmes AJ, Reeves PR. Single-gene long-read sequencing illuminates Escherichia coli strain dynamics in the human intestinal microbiome. Cell Rep 2022; 38:110239. [PMID: 35021078 DOI: 10.1016/j.celrep.2021.110239] [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: 04/05/2021] [Revised: 10/17/2021] [Accepted: 12/17/2021] [Indexed: 02/01/2023] Open
Abstract
Gut microbiome is of major interest due to its close relationship to health and disease. Bacteria usually vary in gene content, leading to functional variations within species, so resolution higher than species-level methods is needed for ecological and clinical relevance. We design a protocol to identify strains in selected species with high discrimination and in high numbers by amplicon sequencing of the flagellin gene. We apply the protocol to fecal samples from a human diet trial, targeting Escherichia coli. Across the 119 samples from 16 individuals, there are 1,532 amplicon sequence variants (ASVs), but only 32 ASVs are dominant in one or more fecal samples, despite frequent dominant strain turnover. Major strains in an intestine are found to be commonly accompanied by a large number of satellite cells, and many are identified as potential extraintestinal pathogens. The protocol could be used to track epidemics or investigate the intra- or inter-host diversity of pathogens.
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Affiliation(s)
- Dalong Hu
- School of Life and Environmental Sciences, Charles Perkins Centre, University of Sydney, Camperdown, NSW 2006, Australia
| | - Nicholas R Fuller
- The Boden Institute, Charles Perkins Centre, University of Sydney, Camperdown, NSW 2006, Australia; Metabolism and Obesity Services, Royal Prince Alfred Hospital, Camperdown, NSW 2050, Australia
| | - Ian D Caterson
- School of Life and Environmental Sciences, Charles Perkins Centre, University of Sydney, Camperdown, NSW 2006, Australia; The Boden Institute, Charles Perkins Centre, University of Sydney, Camperdown, NSW 2006, Australia; Metabolism and Obesity Services, Royal Prince Alfred Hospital, Camperdown, NSW 2050, Australia
| | - Andrew J Holmes
- School of Life and Environmental Sciences, Charles Perkins Centre, University of Sydney, Camperdown, NSW 2006, Australia
| | - Peter R Reeves
- School of Life and Environmental Sciences, Charles Perkins Centre, University of Sydney, Camperdown, NSW 2006, Australia.
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Phylogeographic Clustering Suggests that Distinct Clades of Salmonella enterica Serovar Mississippi Are Endemic in Australia, the United Kingdom, and the United States. mSphere 2021; 6:e0048521. [PMID: 34550008 PMCID: PMC8550085 DOI: 10.1128/msphere.00485-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Salmonella enterica serovar Mississippi is the 2nd and 14th leading cause of human clinical salmonellosis in the Australian island state of Tasmania and the United States, respectively. Despite its public health relevance, relatively little is known about this serovar. Comparison of whole-genome sequence (WGS) data of S. Mississippi isolates with WGS data for 317 additional S. enterica serovars placed one clade of S. Mississippi within S. enterica clade B (“clade B Mississippi”) and the other within section Typhi in S. enterica clade A (“clade A Mississippi”), suggesting that these clades evolved from different ancestors. Phylogenetic analysis of 364 S. Mississippi isolates from Australia, the United Kingdom, and the United States suggested that the isolates cluster geographically, with U.S. and Australian isolates representing different subclades (Ai and Aii, respectively) within clade A Mississippi and clade B isolates representing the predominant S. Mississippi isolates in the United Kingdom. Intraclade comparisons suggested that different mobile elements, some of which encode virulence factors, are responsible for the observed differences in gene content among isolates within these clades. Specifically, genetic differences among clade A isolates reflect differences in prophage contents, while differences among clade B isolates are due to the acquisition of a 47.1-kb integrative conjugative element (ICE). Phylogenies inferred from antigenic components (fliC, fljB, and O-antigen-processing genes) support that clade A and B Mississippi isolates acquired these loci from different ancestral serovars. Overall, these data support that different S. Mississippi phylogenetic clades are endemic in Australia, the United Kingdom, and the United States. IMPORTANCE The number of known so-called “polyphyletic” serovars (i.e., phylogenetically distinct clades with the same O and H antigenic formulas) continues to increase as additional Salmonella isolates are sequenced. While serotyping remains a valuable tool for reporting and monitoring Salmonella, more discriminatory analyses for classifying polyphyletic serovars may improve surveillance efforts for these serovars, as we found that for S. Mississippi, distinct genotypes predominate at different geographic locations. Our results suggest that the acquisition of genes encoding O and H antigens from different ancestors led to the emergence of two Mississippi clades. Furthermore, our results suggest that different mobile elements contribute to the microevolution and diversification of isolates within these two clades, which has implications for the acquisition of novel adaptations, such as virulence factors.
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Pili allow dominant marine cyanobacteria to avoid sinking and evade predation. Nat Commun 2021; 12:1857. [PMID: 33767153 PMCID: PMC7994388 DOI: 10.1038/s41467-021-22152-w] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 03/02/2021] [Indexed: 12/21/2022] Open
Abstract
How oligotrophic marine cyanobacteria position themselves in the water column is currently unknown. The current paradigm is that these organisms avoid sinking due to their reduced size and passive drift within currents. Here, we show that one in four picocyanobacteria encode a type IV pilus which allows these organisms to increase drag and remain suspended at optimal positions in the water column, as well as evade predation by grazers. The evolution of this sophisticated floatation mechanism in these purely planktonic streamlined microorganisms has important implications for our current understanding of microbial distribution in the oceans and predator-prey interactions which ultimately will need incorporating into future models of marine carbon flux dynamics.
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10
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Chomkatekaew C, Boonklang P, Sangphukieo A, Chewapreecha C. An Evolutionary Arms Race Between Burkholderia pseudomallei and Host Immune System: What Do We Know? Front Microbiol 2021; 11:612568. [PMID: 33552023 PMCID: PMC7858667 DOI: 10.3389/fmicb.2020.612568] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 12/21/2020] [Indexed: 12/18/2022] Open
Abstract
A better understanding of co-evolution between pathogens and hosts holds promise for better prevention and control strategies. This review will explore the interactions between Burkholderia pseudomallei, an environmental and opportunistic pathogen, and the human host immune system. B. pseudomallei causes "Melioidosis," a rapidly fatal tropical infectious disease predicted to affect 165,000 cases annually worldwide, of which 89,000 are fatal. Genetic heterogeneities were reported in both B. pseudomallei and human host population, some of which may, at least in part, contribute to inter-individual differences in disease susceptibility. Here, we review (i) a multi-host-pathogen characteristic of the interaction; (ii) selection pressures acting on B. pseudomallei and human genomes with the former being driven by bacterial adaptation across ranges of ecological niches while the latter are driven by human encounter of broad ranges of pathogens; (iii) the mechanisms that generate genetic diversity in bacterial and host population particularly in sequences encoding proteins functioning in host-pathogen interaction; (iv) reported genetic and structural variations of proteins or molecules observed in B. pseudomallei-human host interactions and their implications in infection outcomes. Together, these predict bacterial and host evolutionary trajectory which continues to generate genetic diversity in bacterium and operates host immune selection at the molecular level.
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Affiliation(s)
| | | | - Apiwat Sangphukieo
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Bangkok, Thailand
- Bioinformatics and Systems Biology Program, School of Bioresource and Technology, King Mongkut’s University of Technology Thonburi, Bangkok, Thailand
| | - Claire Chewapreecha
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Bangkok, Thailand
- Bioinformatics and Systems Biology Program, School of Bioresource and Technology, King Mongkut’s University of Technology Thonburi, Bangkok, Thailand
- Wellcome Sanger Institute, Hinxton, United Kingdom
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11
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Eckhard U, Blöchl C, Jenkins BGL, Mansfield MJ, Huber CG, Doxey AC, Brandstetter H. Identification and characterization of the proteolytic flagellin from the common freshwater bacterium Hylemonella gracilis. Sci Rep 2020; 10:19052. [PMID: 33149258 PMCID: PMC7643111 DOI: 10.1038/s41598-020-76010-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 10/22/2020] [Indexed: 12/14/2022] Open
Abstract
Flagellins are the protein components of bacterial flagella and assemble in up to 20,000 copies to form extracellular flagellar filaments. An unusual family of flagellins was recently discovered that contains a unique metalloprotease domain within its surface-exposed hypervariable region. To date, these proteolytic flagellins (also termed flagellinolysins) have only been characterized in the Gram-positive organism Clostridium haemolyticum, where flagellinolysin was shown to be proteolytically active and capable of cleaving extracellular protein substrates. The biological function of flagellinolysin and its activity in other organisms, however, remain unclear. Here, using molecular biochemistry and proteomics, we have performed an initial characterization of a novel flagellinolysin identified from Hylemonella gracilis, a Gram-negative organism originally isolated from pond water. We demonstrate that H. gracilis flagellinolysin (HgrFlaMP) is an active calcium-dependent zinc metallopeptidase and characterize its cleavage specificity profile using both trypsin and GluC-derived peptide libraries and protein substrates. Based on high-throughput degradomic assays, HgrFlaMP cleaved 784 unique peptides and displayed a cleavage site specificity similar to flagellinolysin from C. haemolyticum. Additionally, by using a set of six protein substrates, we identified 206 protein-embedded cleavage sites, further refining the substrate preference of HgrFlaMP, which is dominated by large hydrophobic amino acids in P1', and small hydrophobic or medium-sized polar residues on the amino-terminal side of the scissile bond. Intriguingly, recombinant HgrFlaMP was also capable of cleaving full-length flagellins from another species, suggesting its potential involvement in interbacterial interactions. Our study reports the first experimentally characterized proteolytic flagellin in a Gram-negative organism, and provides new insights into flagellum-mediated enzymatic activity.
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Affiliation(s)
- Ulrich Eckhard
- Department of Biosciences, University of Salzburg, Hellbrunner Straße 34, 5020, Salzburg, Austria. .,Proteolysis Lab, Department of Structural Biology, Molecular Biology Institute of Barcelona, CSIC, Barcelona Science Park, Baldiri Reixac, 15-21, 08028, Barcelona, Catalonia, Spain.
| | - Constantin Blöchl
- Department of Biosciences, University of Salzburg, Hellbrunner Straße 34, 5020, Salzburg, Austria
| | - Benjamin G L Jenkins
- Department of Biology, University of Waterloo, 200 University Ave. West, Waterloo, ON, N2L 3G1, Canada
| | - Michael J Mansfield
- Department of Biology, University of Waterloo, 200 University Ave. West, Waterloo, ON, N2L 3G1, Canada.,Genomics and Regulatory Sytems Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa, 904-0495, Japan
| | - Christian G Huber
- Department of Biosciences, University of Salzburg, Hellbrunner Straße 34, 5020, Salzburg, Austria.,Christian Doppler Laboratory for Innovative Tools for Biosimilar Characterization, University of Salzburg, Hellbrunner Straße 34, 5020, Salzburg, Austria
| | - Andrew C Doxey
- Department of Biology, University of Waterloo, 200 University Ave. West, Waterloo, ON, N2L 3G1, Canada.
| | - Hans Brandstetter
- Department of Biosciences, University of Salzburg, Hellbrunner Straße 34, 5020, Salzburg, Austria.,Christian Doppler Laboratory for Innovative Tools for Biosimilar Characterization, University of Salzburg, Hellbrunner Straße 34, 5020, Salzburg, Austria
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