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Pilgrim J. Comparative genomics of a novel Erwinia species associated with the Highland midge ( Culicoides impunctatus). Microb Genom 2024; 10. [PMID: 38630610 DOI: 10.1099/mgen.0.001242] [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: 04/19/2024] Open
Abstract
Erwinia (Enterobacterales: Erwiniaceae) are a group of cosmopolitan bacteria best known as the causative agents of various plant diseases. However, other species in this genus have been found to play important roles as insect endosymbionts supplementing the diet of their hosts. Here, I describe Candidatus Erwinia impunctatus (Erwimp) associated with the Highland midge Culicoides impunctatus (Diptera: Ceratopogonidae), an abundant biting pest in the Scottish Highlands. The genome of this new Erwinia species was assembled using hybrid long and short read techniques, and a comparative analysis was undertaken with other members of the genus to understand its potential ecological niche and impact. Genome composition analysis revealed that Erwimp is similar to other endophytic and ectophytic species in the genus and is unlikely to be restricted to its insect host. Evidence for an additional plant host includes the presence of a carotenoid synthesis operon implicated as a virulence factor in plant-associated members in the sister genus Pantoea. Unique features of Erwimp include several copies of intimin-like proteins which, along with signs of genome pseudogenization and a loss of certain metabolic pathways, suggests an element of host restriction seen elsewhere in the genus. Furthermore, a screening of individuals over two field seasons revealed the absence of the bacteria in Culicoides impunctatus during the second year indicating this microbe-insect interaction is likely to be transient. These data suggest that Culicoides impunctatus may have an important role to play beyond a biting nuisance, as an insect vector transmitting Erwimp alongside any conferred impacts to surrounding biota.
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Affiliation(s)
- Jack Pilgrim
- Institute of Infection, Veterinary and Ecological Sciences, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, UK
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2
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Zhu S, Wang X, Zhao W, Zhang Y, Song D, Cheng H, Zhang XH. Vertical dynamics of free-living and particle-associated vibrio communities in the eastern tropical Indian Ocean. Front Microbiol 2023; 14:1285670. [PMID: 37928659 PMCID: PMC10620696 DOI: 10.3389/fmicb.2023.1285670] [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] [Received: 08/30/2023] [Accepted: 09/19/2023] [Indexed: 11/07/2023] Open
Abstract
Members of the family Vibrionaceae (vibrios) are widely distributed in estuarine, offshore, and marginal seas and perform an important ecological role in the marine organic carbon cycle. Nevertheless, there is little knowledge about whether vibrios play ecological roles in the oligotrophic pelagic area, which occupies a larger water volume. In this study, we investigated the abundance, diversity, and composition of free-living and particle-associated vibrios and their relationships with environmental factors along the water depth in the eastern tropical Indian Ocean (ETIO). The abundance of vibrios in free-living fractions was significantly higher than that of particle-associated fractions on the surface. Still, both were similar at the bottom, indicating that vibrios may shift from free-living lifestyles on the surface to mixed lifestyles at the bottom. Vibrio-specific 16S rRNA gene amplicon sequencing revealed that Paraphotobacterium marinum and Vibrio rotiferianus were dominant species in the water column, and Vibrio parahaemolyticus (a clinically important pathogen) was recorded in 102 samples of 111 seawater samples in 10 sites, which showed significant difference from the marginal seas. The community composition also shifted, corresponding to different depths in the water column. Paraphotobacterium marinum decreased with depth, and V. rotiferianus OTU1528 was mainly distributed in deeper water, which significantly correlated with the alteration of environmental factors (e.g., temperature, salinity, and dissolved oxygen). In addition to temperature and salinity, dissolved oxygen (DO) was an important factor that affected the composition and abundance of Vibrio communities in the ETIO. Our study revealed the vertical dynamics and preferential lifestyles of vibrios in the ETIO, helping to fill a knowledge gap on their ecological distribution in oligotrophic pelagic areas and fully understanding the response of vibrios in a global warming environment.
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Affiliation(s)
- Shaodong Zhu
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, and College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Xiaolei Wang
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, and College of Marine Life Sciences, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao, China
| | - Wenbin Zhao
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, and College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Yulin Zhang
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, and College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Derui Song
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, and College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Haojin Cheng
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, and College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Xiao-Hua Zhang
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, and College of Marine Life Sciences, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao, China
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China
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3
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Abianeh HS, Nazarian S, Sadeghi D, Razgi ASH, Samarin MZ. PLGA nanoparticles containing Intimin-Flagellin fusion protein for E. coli O157:H7 nano-vaccine. J Immunol Methods 2023; 520:113517. [PMID: 37385434 DOI: 10.1016/j.jim.2023.113517] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 06/25/2023] [Accepted: 06/26/2023] [Indexed: 07/01/2023]
Abstract
Escherichia coli O157:H7 is a foodborne pathogen that can lead to severe gastrointestinal diseases in humans. Vaccination is a promising strategy for preventing E. coli O157:H7 infections, which offers socio-economic benefits and provides the possibility of stimulating both humoral and cellular immune responses at systemic and mucosal sites. In this study, we developed a needle-free vaccine candidate against E. coli O157:H7 using poly(lactic-co-glycolic acid) (PLGA) nanoparticles entrapping a chimeric Intimin-Flagellin (IF) protein. The IF protein was expressed and verified using SDS-PAGE and western blot analysis, with a yield of 1/7 mg/L and a molecular weight of approximately 70 kDa. The prepared nanoparticles showed uniformly shaped spherical particles in the 200-nm range, as confirmed by SEM and DLS analysis. Three different routes of vaccine administration were used, including intranasal, oral, and subcutaneous, and the groups vaccinated with NPs protein had a higher antibody response compared to those receiving free protein. Subcutaneous administration of IF-NPs resulted in the highest level of IgG antibody titer, while oral administration of IF-NPs produced the highest amount of IgA antibody titer. Finally, all mice in the nanoparticle- intranasal and oral administered groups challenged with 100LD50 survived, while all control mice died before day 5. Based on these findings, we conclude that the PLGA-encapsulated IF protein has the potential to serve as a promising needle-free vaccine candidate against E. coli O157:H7.
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Affiliation(s)
- Hossein Samiei Abianeh
- Department of Medical Biotechnology and Nanotechnology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran; Department of Biology, Faculty of Basic Sciences, Imam Hossein University, Tehran, Iran
| | - Shahram Nazarian
- Department of Biology, Faculty of Basic Sciences, Imam Hossein University, Tehran, Iran.
| | - Davoud Sadeghi
- Department of Biology, Faculty of Basic Sciences, Imam Hossein University, Tehran, Iran.
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Riborg A, Gulla S, Fiskebeck EZ, Ryder D, Verner-Jeffreys DW, Colquhoun DJ, Welch TJ. Pan-genome survey of the fish pathogen Yersinia ruckeri links accessory- and amplified genes to virulence. PLoS One 2023; 18:e0285257. [PMID: 37167256 PMCID: PMC10174560 DOI: 10.1371/journal.pone.0285257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Accepted: 04/18/2023] [Indexed: 05/13/2023] Open
Abstract
While both virulent and putatively avirulent Yersinia ruckeri strains exist in aquaculture environments, the relationship between the distribution of virulence-associated factors and de facto pathogenicity in fish remains poorly understood. Pan-genome analysis of 18 complete genomes, representing established virulent and putatively avirulent lineages of Y. ruckeri, revealed the presence of a number of accessory genetic determinants. Further investigation of 68 draft genome assemblies revealed that the distribution of certain putative virulence factors correlated well with virulence and host-specificity. The inverse-autotransporter invasin locus yrIlm was, however, the only gene present in all virulent strains, while absent in lineages regarded as avirulent. Strains known to be associated with significant mortalities in salmonid aquaculture display a combination of serotype O1-LPS and yrIlm, with the well-documented highly virulent lineages, represented by MLVA clonal complexes 1 and 2, displaying duplication of the yrIlm locus. Duplication of the yrIlm locus was further found to have evolved over time in clonal complex 1, where some modern, highly virulent isolates display up to three copies.
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Affiliation(s)
- Andreas Riborg
- Norwegian Veterinary Institute, Ås, Norway
- Vaxxinova Norway AS, Bergen, Norway
| | | | | | - David Ryder
- Centre for Environment, Fisheries and Aquaculture Science (CEFAS), Weymouth, Dorset, United Kingdom
| | - David W Verner-Jeffreys
- Centre for Environment, Fisheries and Aquaculture Science (CEFAS), Weymouth, Dorset, United Kingdom
| | - Duncan J Colquhoun
- Norwegian Veterinary Institute, Ås, Norway
- University of Bergen, Bergen, Norway
| | - Timothy J Welch
- National Centre for Cool and Coldwater Aquaculture, USDA-ARS, Leetown, WV, United States of America
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5
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Gupta A, Malwe AS, Srivastava GN, Thoudam P, Hibare K, Sharma VK. MP4: a machine learning based classification tool for prediction and functional annotation of pathogenic proteins from metagenomic and genomic datasets. BMC Bioinformatics 2022; 23:507. [PMID: 36443666 PMCID: PMC9703692 DOI: 10.1186/s12859-022-05061-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2021] [Accepted: 11/16/2022] [Indexed: 11/29/2022] Open
Abstract
Bacteria can exceptionally evolve and develop pathogenic features making it crucial to determine novel pathogenic proteins for specific therapeutic interventions. Therefore, we have developed a machine-learning tool that predicts and functionally classifies pathogenic proteins into their respective pathogenic classes. Through construction of pathogenic proteins database and optimization of ML algorithms, Support Vector Machine was selected for the model construction. The developed SVM classifier yielded an accuracy of 81.72% on the blind-dataset and classified the proteins into three classes: Non-pathogenic proteins (Class-1), Antibiotic Resistance Proteins and Toxins (Class-2), and Secretory System Associated and capsular proteins (Class-3). The classifier provided an accuracy of 79% on real dataset-1, and 72% on real dataset-2. Based on the probability of prediction, users can estimate the pathogenicity and annotation of proteins under scrutiny. Tool will provide accurate prediction of pathogenic proteins in genomic and metagenomic datasets providing leads for experimental validations. Tool is available at: http://metagenomics.iiserb.ac.in/mp4 .
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Affiliation(s)
- Ankit Gupta
- grid.462376.20000 0004 1763 8131MetaBioSys Group, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, Madhya Pradesh India
| | - Aditya S. Malwe
- grid.462376.20000 0004 1763 8131MetaBioSys Group, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, Madhya Pradesh India
| | - Gopal N. Srivastava
- grid.462376.20000 0004 1763 8131MetaBioSys Group, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, Madhya Pradesh India
| | - Parikshit Thoudam
- grid.462376.20000 0004 1763 8131MetaBioSys Group, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, Madhya Pradesh India
| | - Keshav Hibare
- grid.462376.20000 0004 1763 8131MetaBioSys Group, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, Madhya Pradesh India
| | - Vineet K. Sharma
- grid.462376.20000 0004 1763 8131MetaBioSys Group, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, Madhya Pradesh India
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6
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The long and the short of Periscope Proteins. Biochem Soc Trans 2022; 50:1293-1302. [PMID: 36196877 DOI: 10.1042/bst20220194] [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: 07/26/2022] [Revised: 09/10/2022] [Accepted: 09/13/2022] [Indexed: 11/17/2022]
Abstract
Bacteria sense, interact with, and modify their environmental niche by deploying a molecular ensemble at the cell surface. The changeability of this exposed interface, combined with extreme changes in the functional repertoire associated with lifestyle switches from planktonic to adherent and biofilm states necessitate dynamic variability. Dynamic surface changes include chemical modifications to the cell wall; export of diverse extracellular biofilm components; and modulation of expression of cell surface proteins for adhesion, co-aggregation and virulence. Local enrichment for highly repetitive proteins with high tandem repeat identity has been an enigmatic phenomenon observed in diverse bacterial species. Preliminary observations over decades of research suggested these repeat regions were hypervariable, as highly related strains appeared to express homologues with diverse molecular mass. Long-read sequencing data have been interrogated to reveal variation in repeat number; in combination with structural, biophysical and molecular dynamics approaches, the Periscope Protein class has been defined for cell surface attached proteins that dynamically expand and contract tandem repeat tracts at the population level. Here, I review the diverse high-stability protein folds and coherent interdomain linkages culminating in the formation of highly anisotropic linear repeat arrays, so-called rod-like protein 'stalks', supporting roles in bacterial adhesion, biofilm formation, cell surface spatial competition, and immune system modulation. An understanding of the functional impacts of dynamic changes in repeat arrays and broader characterisation of the unusual protein folds underpinning this variability will help with the design of immunisation strategies, and contribute to synthetic biology approaches including protein engineering and microbial consortia construction.
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Clarke KR, Hor L, Pilapitiya A, Luirink J, Paxman JJ, Heras B. Phylogenetic Classification and Functional Review of Autotransporters. Front Immunol 2022; 13:921272. [PMID: 35860281 PMCID: PMC9289746 DOI: 10.3389/fimmu.2022.921272] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 06/06/2022] [Indexed: 11/30/2022] Open
Abstract
Autotransporters are the core component of a molecular nano-machine that delivers cargo proteins across the outer membrane of Gram-negative bacteria. Part of the type V secretion system, this large family of proteins play a central role in controlling bacterial interactions with their environment by promoting adhesion to surfaces, biofilm formation, host colonization and invasion as well as cytotoxicity and immunomodulation. As such, autotransporters are key facilitators of fitness and pathogenesis and enable co-operation or competition with other bacteria. Recent years have witnessed a dramatic increase in the number of autotransporter sequences reported and a steady rise in functional studies, which further link these proteins to multiple virulence phenotypes. In this review we provide an overview of our current knowledge on classical autotransporter proteins, the archetype of this protein superfamily. We also carry out a phylogenetic analysis of their functional domains and present a new classification system for this exquisitely diverse group of bacterial proteins. The sixteen phylogenetic divisions identified establish sensible relationships between well characterized autotransporters and inform structural and functional predictions of uncharacterized proteins, which may guide future research aimed at addressing multiple unanswered aspects in this group of therapeutically important bacterial factors.
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Affiliation(s)
- Kaitlin R. Clarke
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Lilian Hor
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Akila Pilapitiya
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Joen Luirink
- Department of Molecular Microbiology, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Vrije Universiteit, Amsterdam, Netherlands
| | - Jason J. Paxman
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
- *Correspondence: Begoña Heras, ; Jason J. Paxman,
| | - Begoña Heras
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
- *Correspondence: Begoña Heras, ; Jason J. Paxman,
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InvL, an Invasin-Like Adhesin, Is a Type II Secretion System Substrate Required for Acinetobacter baumannii Uropathogenesis. mBio 2022; 13:e0025822. [PMID: 35638734 PMCID: PMC9245377 DOI: 10.1128/mbio.00258-22] [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] [Indexed: 02/08/2023] Open
Abstract
Acinetobacter baumannii is an opportunistic pathogen of growing concern, as isolates are commonly multidrug resistant. While A. baumannii is most frequently associated with pulmonary infections, a significant proportion of clinical isolates come from urinary sources, highlighting its uropathogenic potential. The type II secretion system (T2SS) of commonly used model Acinetobacter strains is important for virulence in various animal models, but the potential role of the T2SS in urinary tract infection (UTI) remains unknown. Here, we used a catheter-associated UTI (CAUTI) model to demonstrate that a modern urinary isolate, UPAB1, requires the T2SS for full virulence. A proteomic screen to identify putative UPAB1 T2SS effectors revealed an uncharacterized lipoprotein with structural similarity to the intimin-invasin family, which serve as type V secretion system (T5SS) adhesins required for the pathogenesis of several bacteria. This protein, designated InvL, lacked the β-barrel domain associated with T5SSs but was confirmed to require the T2SS for both surface localization and secretion. This makes InvL the first identified T2SS effector belonging to the intimin-invasin family. InvL was confirmed to be an adhesin, as the protein bound to extracellular matrix components and mediated adhesion to urinary tract cell lines in vitro. Additionally, the invL mutant was attenuated in the CAUTI model, indicating a role in Acinetobacter uropathogenesis. Finally, bioinformatic analyses revealed that InvL is present in nearly all clinical isolates belonging to international clone 2, a lineage of significant clinical importance. In all, we conclude that the T2SS substrate InvL is an adhesin required for A. baumannii uropathogenesis. IMPORTANCE While pathogenic Acinetobacter can cause various infections, we recently found that 20% of clinical isolates come from urinary sources. Despite the clinical relevance of Acinetobacter as a uropathogen, few virulence factors involved in urinary tract colonization have been defined. Here, we identify a novel type II secretion system effector, InvL, which is required for full uropathogenesis by a modern urinary isolate. Although InvL has predicted structural similarity to the intimin-invasin family of autotransporter adhesins, InvL is predicted to be anchored to the membrane as a lipoprotein. Similar to other invasin homologs, however, we demonstrate that InvL is a bona fide adhesin capable of binding extracellular matrix components and mediating adhesion to urinary tract cell lines. In all, this work establishes InvL as an adhesin important for Acinetobacter's urinary tract virulence and represents the first report of a type II secretion system effector belonging to the intimin-invasin family.
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Pseudomonas aeruginosa: pathogenesis, virulence factors, antibiotic resistance, interaction with host, technology advances and emerging therapeutics. Signal Transduct Target Ther 2022; 7:199. [PMID: 35752612 PMCID: PMC9233671 DOI: 10.1038/s41392-022-01056-1] [Citation(s) in RCA: 253] [Impact Index Per Article: 126.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 06/04/2022] [Accepted: 06/08/2022] [Indexed: 02/05/2023] Open
Abstract
Pseudomonas aeruginosa (P. aeruginosa) is a Gram-negative opportunistic pathogen that infects patients with cystic fibrosis, burn wounds, immunodeficiency, chronic obstructive pulmonary disorder (COPD), cancer, and severe infection requiring ventilation, such as COVID-19. P. aeruginosa is also a widely-used model bacterium for all biological areas. In addition to continued, intense efforts in understanding bacterial pathogenesis of P. aeruginosa including virulence factors (LPS, quorum sensing, two-component systems, 6 type secretion systems, outer membrane vesicles (OMVs), CRISPR-Cas and their regulation), rapid progress has been made in further studying host-pathogen interaction, particularly host immune networks involving autophagy, inflammasome, non-coding RNAs, cGAS, etc. Furthermore, numerous technologic advances, such as bioinformatics, metabolomics, scRNA-seq, nanoparticles, drug screening, and phage therapy, have been used to improve our understanding of P. aeruginosa pathogenesis and host defense. Nevertheless, much remains to be uncovered about interactions between P. aeruginosa and host immune responses, including mechanisms of drug resistance by known or unannotated bacterial virulence factors as well as mammalian cell signaling pathways. The widespread use of antibiotics and the slow development of effective antimicrobials present daunting challenges and necessitate new theoretical and practical platforms to screen and develop mechanism-tested novel drugs to treat intractable infections, especially those caused by multi-drug resistance strains. Benefited from has advancing in research tools and technology, dissecting this pathogen's feature has entered into molecular and mechanistic details as well as dynamic and holistic views. Herein, we comprehensively review the progress and discuss the current status of P. aeruginosa biophysical traits, behaviors, virulence factors, invasive regulators, and host defense patterns against its infection, which point out new directions for future investigation and add to the design of novel and/or alternative therapeutics to combat this clinically significant pathogen.
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Péter B, Farkas E, Kurunczi S, Szittner Z, Bősze S, Ramsden JJ, Szekacs I, Horvath R. Review of Label-Free Monitoring of Bacteria: From Challenging Practical Applications to Basic Research Perspectives. BIOSENSORS 2022; 12:bios12040188. [PMID: 35448248 PMCID: PMC9026780 DOI: 10.3390/bios12040188] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 03/07/2022] [Accepted: 03/11/2022] [Indexed: 05/10/2023]
Abstract
Novel biosensors already provide a fast way to detect the adhesion of whole bacteria (or parts of them), biofilm formation, and the effect of antibiotics. Moreover, the detection sensitivities of recent sensor technologies are large enough to investigate molecular-scale biological processes. Usually, these measurements can be performed in real time without using labeling. Despite these excellent capabilities summarized in the present work, the application of novel, label-free sensor technologies in basic biological research is still rare; the literature is dominated by heuristic work, mostly monitoring the presence and amount of a given analyte. The aims of this review are (i) to give an overview of the present status of label-free biosensors in bacteria monitoring, and (ii) to summarize potential novel directions with biological relevancies to initiate future development. Optical, mechanical, and electrical sensing technologies are all discussed with their detailed capabilities in bacteria monitoring. In order to review potential future applications of the outlined techniques in bacteria research, we summarize the most important kinetic processes relevant to the adhesion and survival of bacterial cells. These processes are potential targets of kinetic investigations employing modern label-free technologies in order to reveal new fundamental aspects. Resistance to antibacterials and to other antimicrobial agents, the most important biological mechanisms in bacterial adhesion and strategies to control adhesion, as well as bacteria-mammalian host cell interactions are all discussed with key relevancies to the future development and applications of biosensors.
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Affiliation(s)
- Beatrix Péter
- Nanobiosensorics Laboratory, Centre for Energy Research, Institute of Technical Physics and Materials Science, 1121 Budapest, Hungary; (E.F.); (S.K.); (Z.S.); (I.S.)
- Correspondence: (B.P.); (R.H.)
| | - Eniko Farkas
- Nanobiosensorics Laboratory, Centre for Energy Research, Institute of Technical Physics and Materials Science, 1121 Budapest, Hungary; (E.F.); (S.K.); (Z.S.); (I.S.)
| | - Sandor Kurunczi
- Nanobiosensorics Laboratory, Centre for Energy Research, Institute of Technical Physics and Materials Science, 1121 Budapest, Hungary; (E.F.); (S.K.); (Z.S.); (I.S.)
| | - Zoltán Szittner
- Nanobiosensorics Laboratory, Centre for Energy Research, Institute of Technical Physics and Materials Science, 1121 Budapest, Hungary; (E.F.); (S.K.); (Z.S.); (I.S.)
| | - Szilvia Bősze
- MTA-ELTE Research Group of Peptide Chemistry, Eötvös Loránd Research Network (ELKH), Institute of Chemistry, Eötvös Loránd University, 1120 Budapest, Hungary;
- National Public Health Center, 1097 Budapest, Hungary
| | - Jeremy J. Ramsden
- Clore Laboratory, Department of Biomedical Research, University of Buckingham, Buckingham MK18 1AD, UK;
| | - Inna Szekacs
- Nanobiosensorics Laboratory, Centre for Energy Research, Institute of Technical Physics and Materials Science, 1121 Budapest, Hungary; (E.F.); (S.K.); (Z.S.); (I.S.)
| | - Robert Horvath
- Nanobiosensorics Laboratory, Centre for Energy Research, Institute of Technical Physics and Materials Science, 1121 Budapest, Hungary; (E.F.); (S.K.); (Z.S.); (I.S.)
- Correspondence: (B.P.); (R.H.)
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Mekasha S, Linke D. Secretion Systems in Gram-Negative Bacterial Fish Pathogens. Front Microbiol 2022; 12:782673. [PMID: 34975803 PMCID: PMC8714846 DOI: 10.3389/fmicb.2021.782673] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 11/24/2021] [Indexed: 12/17/2022] Open
Abstract
Bacterial fish pathogens are one of the key challenges in the aquaculture industry, one of the fast-growing industries worldwide. These pathogens rely on arsenal of virulence factors such as toxins, adhesins, effectors and enzymes to promote colonization and infection. Translocation of virulence factors across the membrane to either the extracellular environment or directly into the host cells is performed by single or multiple dedicated secretion systems. These secretion systems are often key to the infection process. They can range from simple single-protein systems to complex injection needles made from dozens of subunits. Here, we review the different types of secretion systems in Gram-negative bacterial fish pathogens and describe their putative roles in pathogenicity. We find that the available information is fragmented and often descriptive, and hope that our overview will help researchers to more systematically learn from the similarities and differences between the virulence factors and secretion systems of the fish-pathogenic species described here.
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Affiliation(s)
- Sophanit Mekasha
- Section for Genetics and Evolutionary Biology, Department of Biosciences, University of Oslo, Oslo, Norway
| | - Dirk Linke
- Section for Genetics and Evolutionary Biology, Department of Biosciences, University of Oslo, Oslo, Norway
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12
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Abstract
Pathogen attachment to host tissue is critical in the progress of many infections. Bacteria use adhesion in vivo to stabilize colonization and subsequently regulate the deployment of contact-dependent virulence traits. To specifically target host cells, they decorate themselves with adhesins, proteins that bind to mammalian cell surface receptors. One common assumption is that adhesin-receptor interactions entirely govern bacterial attachment. However, how adhesins engage with their receptors in an in vivo-like context remains unclear, in particular under the influence of a heterogeneous mechanical microenvironment. We here investigate the biophysical processes governing bacterial adhesion to host cells using a tunable adhesin-receptor system. By dynamically visualizing attachment, we found that bacterial adhesion to host cell surface, unlike adhesion to inert surfaces, involves two consecutive steps. Bacteria initially attach to their host without engaging adhesins. This step lasts about 1 min, during which bacteria can easily detach. We found that at this stage, the glycocalyx, a layer of glycosylated proteins and lipids, shields the host cell by keeping adhesins away from their receptor ligand. In a second step, adhesins engage with their target receptors to strengthen attachment for minutes to hours. The active properties of the membrane, endowed by the actin cytoskeleton, strengthen specific adhesion. Altogether, our results demonstrate that adhesin-ligand binding is not the sole regulator of bacterial adhesion. In fact, the host cell’s surface mechanical microenvironment mediates the physical interactions between host and bacteria, thereby playing an essential role in the onset of infection.
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Dautin N. Folding Control in the Path of Type 5 Secretion. Toxins (Basel) 2021; 13:341. [PMID: 34064645 PMCID: PMC8151025 DOI: 10.3390/toxins13050341] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 05/04/2021] [Accepted: 05/05/2021] [Indexed: 12/17/2022] Open
Abstract
The type 5 secretion system (T5SS) is one of the more widespread secretion systems in Gram-negative bacteria. Proteins secreted by the T5SS are functionally diverse (toxins, adhesins, enzymes) and include numerous virulence factors. Mechanistically, the T5SS has long been considered the simplest of secretion systems, due to the paucity of proteins required for its functioning. Still, despite more than two decades of study, the exact process by which T5SS substrates attain their final destination and correct conformation is not totally deciphered. Moreover, the recent addition of new sub-families to the T5SS raises additional questions about this secretion mechanism. Central to the understanding of type 5 secretion is the question of protein folding, which needs to be carefully controlled in each of the bacterial cell compartments these proteins cross. Here, the biogenesis of proteins secreted by the Type 5 secretion system is discussed, with a focus on the various factors preventing or promoting protein folding during biogenesis.
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Affiliation(s)
- Nathalie Dautin
- Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, Université de Paris, LBPC-PM, CNRS, UMR7099, 75005 Paris, France;
- Institut de Biologie Physico-Chimique, Fondation Edmond de Rothschild pour le Développement de la Recherche Scientifique, 75005 Paris, France
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14
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Queiroz MG, Elsztein C, Strahl S, de Morais Junior MA. The Saccharomyces cerevisiae Ncw2 protein works on the chitin/β-glucan organisation of the cell wall. Antonie van Leeuwenhoek 2021; 114:1141-1153. [PMID: 33945065 DOI: 10.1007/s10482-021-01584-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Accepted: 04/17/2021] [Indexed: 11/28/2022]
Abstract
The NCW2 gene was recently described as encoding a GPI-bounded protein that assists in the re-modelling of the Saccharomyces cerevisiae cell wall (CW) and in the repair of damage caused by the polyhexamethylene biguanide (PHMB) polymer to the cell wall. Its absence produces a re-organization of the CW structure that result in resistance to lysis by glucanase. Hence, the present study aimed to extend the analysis of the Ncw2 protein (Ncw2p) to determine its physiological role in the yeast cell surface. The results showed that Ncw2p is transported to the cell surface upon O-mannosylation mediated by the Pmt1p-Pmt2p enzyme complex. It co-localises with the yeast bud scars, a region in cell surface formed by chitin deposition. Once there, Ncw2p enables correct chitin/β-glucan structuring during the exponential growth. The increase in molecular mass by hyper-mannosylation coincides with the increasing in chitin deposition, and leads to glucanase resistance. Treatment of the yeast cells with PHMB produced the same biological effects observed for the passage from exponential to stationary growth phase. This might be a possible mechanism of yeast protection against cationic biocides. In conclusion, we propose that Ncw2p takes part in the mechanism involved in the control of cell surface rigidity by aiding on the linkage between chitin and glucan layers in the modelling of the cell wall during cell growth.
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Affiliation(s)
- Maise Gomes Queiroz
- Laboratory of Microbial Genetics, Department of Genetics, Federal University of Pernambuco, Recife, Brazil
| | - Carolina Elsztein
- Laboratory of Microbial Genetics, Department of Genetics, Federal University of Pernambuco, Recife, Brazil
| | - Sabine Strahl
- Laboratory of Glycobiology, Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany
| | - Marcos Antonio de Morais Junior
- Laboratory of Microbial Genetics, Department of Genetics, Federal University of Pernambuco, Recife, Brazil. .,Departamento de Genética, Universidade Federal de Pernambuco, Av. Moraes Rego, 1235, Cidade Universitária, Recife, PE, 50.670-901, Brasil.
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15
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Wimmi S, Balinovic A, Jeckel H, Selinger L, Lampaki D, Eisemann E, Meuskens I, Linke D, Drescher K, Endesfelder U, Diepold A. Dynamic relocalization of cytosolic type III secretion system components prevents premature protein secretion at low external pH. Nat Commun 2021; 12:1625. [PMID: 33712575 PMCID: PMC7954860 DOI: 10.1038/s41467-021-21863-4] [Citation(s) in RCA: 9] [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: 03/27/2020] [Accepted: 02/12/2021] [Indexed: 01/31/2023] Open
Abstract
Many bacterial pathogens use a type III secretion system (T3SS) to manipulate host cells. Protein secretion by the T3SS injectisome is activated upon contact to any host cell, and it has been unclear how premature secretion is prevented during infection. Here we report that in the gastrointestinal pathogens Yersinia enterocolitica and Shigella flexneri, cytosolic injectisome components are temporarily released from the proximal interface of the injectisome at low external pH, preventing protein secretion in acidic environments, such as the stomach. We show that in Yersinia enterocolitica, low external pH is detected in the periplasm and leads to a partial dissociation of the inner membrane injectisome component SctD, which in turn causes the dissociation of the cytosolic T3SS components. This effect is reversed upon restoration of neutral pH, allowing a fast activation of the T3SS at the native target regions within the host. These findings indicate that the cytosolic components form an adaptive regulatory interface, which regulates T3SS activity in response to environmental conditions.
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Affiliation(s)
- Stephan Wimmi
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Alexander Balinovic
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
- Department of Physics, Mellon College of Science, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Hannah Jeckel
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
- Department of Physics, Philipps-Universität Marburg, Marburg, Germany
| | - Lisa Selinger
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Dimitrios Lampaki
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
- Max-Planck-Institut für Immunbiologie und Epigenetik, Freiburg, Germany
| | - Emma Eisemann
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
- James Madison University, Harrisonburg, VA, USA
| | - Ina Meuskens
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Dirk Linke
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Knut Drescher
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
- Department of Physics, Philipps-Universität Marburg, Marburg, Germany
| | - Ulrike Endesfelder
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
- Department of Physics, Mellon College of Science, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Andreas Diepold
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany.
- SYNMIKRO, LOEWE Center for Synthetic Microbiology, Marburg, Germany.
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16
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Ageorges V, Monteiro R, Leroy S, Burgess CM, Pizza M, Chaucheyras-Durand F, Desvaux M. Molecular determinants of surface colonisation in diarrhoeagenic Escherichia coli (DEC): from bacterial adhesion to biofilm formation. FEMS Microbiol Rev 2021; 44:314-350. [PMID: 32239203 DOI: 10.1093/femsre/fuaa008] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 03/31/2020] [Indexed: 12/11/2022] Open
Abstract
Escherichia coli is primarily known as a commensal colonising the gastrointestinal tract of infants very early in life but some strains being responsible for diarrhoea, which can be especially severe in young children. Intestinal pathogenic E. coli include six pathotypes of diarrhoeagenic E. coli (DEC), namely, the (i) enterotoxigenic E. coli, (ii) enteroaggregative E. coli, (iii) enteropathogenic E. coli, (iv) enterohemorragic E. coli, (v) enteroinvasive E. coli and (vi) diffusely adherent E. coli. Prior to human infection, DEC can be found in natural environments, animal reservoirs, food processing environments and contaminated food matrices. From an ecophysiological point of view, DEC thus deal with very different biotopes and biocoenoses all along the food chain. In this context, this review focuses on the wide range of surface molecular determinants acting as surface colonisation factors (SCFs) in DEC. In the first instance, SCFs can be broadly discriminated into (i) extracellular polysaccharides, (ii) extracellular DNA and (iii) surface proteins. Surface proteins constitute the most diverse group of SCFs broadly discriminated into (i) monomeric SCFs, such as autotransporter (AT) adhesins, inverted ATs, heat-resistant agglutinins or some moonlighting proteins, (ii) oligomeric SCFs, namely, the trimeric ATs and (iii) supramolecular SCFs, including flagella and numerous pili, e.g. the injectisome, type 4 pili, curli chaperone-usher pili or conjugative pili. This review also details the gene regulatory network of these numerous SCFs at the various stages as it occurs from pre-transcriptional to post-translocational levels, which remains to be fully elucidated in many cases.
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Affiliation(s)
- Valentin Ageorges
- Université Clermont Auvergne, INRAE, MEDiS, F-63000 Clermont-Ferrand, France
| | - Ricardo Monteiro
- Université Clermont Auvergne, INRAE, MEDiS, F-63000 Clermont-Ferrand, France.,GSK, Via Fiorentina 1, 53100 Siena, Italy
| | - Sabine Leroy
- Université Clermont Auvergne, INRAE, MEDiS, F-63000 Clermont-Ferrand, France
| | - Catherine M Burgess
- Food Safety Department, Teagasc Food Research Centre, Ashtown, Dublin 15, Ireland
| | | | - Frédérique Chaucheyras-Durand
- Université Clermont Auvergne, INRAE, MEDiS, F-63000 Clermont-Ferrand, France.,Lallemand Animal Nutrition SAS, F-31702 Blagnac Cedex, France
| | - Mickaël Desvaux
- Université Clermont Auvergne, INRAE, MEDiS, F-63000 Clermont-Ferrand, France
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17
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Rooke JL, Icke C, Wells TJ, Rossiter AE, Browning DF, Morris FC, Leo JC, Schütz MS, Autenrieth IB, Cunningham AF, Linke D, Henderson IR. BamA and BamD Are Essential for the Secretion of Trimeric Autotransporter Adhesins. Front Microbiol 2021; 12:628879. [PMID: 33708185 PMCID: PMC7940764 DOI: 10.3389/fmicb.2021.628879] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 01/26/2021] [Indexed: 12/14/2022] Open
Abstract
The BAM complex in Escherichia coli is composed of five proteins, BamA-E. BamA and BamD are essential for cell viability and are required for the assembly of β-barrel outer membrane proteins. Consequently, BamA and BamD are indispensable for secretion via the classical autotransporter pathway (Type 5a secretion). In contrast, BamB, BamC, and BamE are not required for the biogenesis of classical autotransporters. Recently, we demonstrated that TamA, a homologue of BamA, and its partner protein TamB, were required for efficient secretion of proteins via the classical autotransporter pathway. The trimeric autotransporters are a subset of the Type 5-secreted proteins. Unlike the classical autotransporters, they are composed of three identical polypeptide chains which must be assembled together to allow secretion of their cognate passenger domains. In contrast to the classical autotransporters, the role of the Bam and Tam complex components in the biogenesis of the trimeric autotransporters has not been investigated fully. Here, using the Salmonella enterica trimeric autotransporter SadA and the structurally similar YadA protein of Yersinia spp., we identify the importance of BamA and BamD in the biogenesis of the trimeric autotransporters and reveal that BamB, BamC, BamE, TamA and TamB are not required for secretion of functional passenger domain on the cell surface. Importance The secretion of trimeric autotransporters (TAA's) has yet to be fully understood. Here we show that efficient secretion of TAAs requires the BamA and D proteins, but does not require BamB, C or E. In contrast to classical autotransporter secretion, neither trimeric autotransporter tested required TamA or B proteins to be functionally secreted.
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Affiliation(s)
- Jessica L Rooke
- Institute for Molecular Bioscience, University of Queensland, St Lucia, QLD, Australia.,Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Christopher Icke
- Institute for Molecular Bioscience, University of Queensland, St Lucia, QLD, Australia.,Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Timothy J Wells
- Institute for Molecular Bioscience, University of Queensland, St Lucia, QLD, Australia.,The University of Queensland Diamantina Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Amanda E Rossiter
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Douglas F Browning
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Faye C Morris
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Jack C Leo
- Department of Biosciences, Nottingham Trent University, Nottingham, United Kingdom.,Department of Biosciences, University of Oslo, Oslo, Norway
| | - Monika S Schütz
- Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum Tübingen, Tübingen, Germany
| | - Ingo B Autenrieth
- Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum Tübingen, Tübingen, Germany
| | - Adam F Cunningham
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, United Kingdom
| | - Dirk Linke
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Ian R Henderson
- Institute for Molecular Bioscience, University of Queensland, St Lucia, QLD, Australia.,Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
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18
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Roop RM, Barton IS, Hopersberger D, Martin DW. Uncovering the Hidden Credentials of Brucella Virulence. Microbiol Mol Biol Rev 2021; 85:e00021-19. [PMID: 33568459 PMCID: PMC8549849 DOI: 10.1128/mmbr.00021-19] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Bacteria in the genus Brucella are important human and veterinary pathogens. The abortion and infertility they cause in food animals produce economic hardships in areas where the disease has not been controlled, and human brucellosis is one of the world's most common zoonoses. Brucella strains have also been isolated from wildlife, but we know much less about the pathobiology and epidemiology of these infections than we do about brucellosis in domestic animals. The brucellae maintain predominantly an intracellular lifestyle in their mammalian hosts, and their ability to subvert the host immune response and survive and replicate in macrophages and placental trophoblasts underlies their success as pathogens. We are just beginning to understand how these bacteria evolved from a progenitor alphaproteobacterium with an environmental niche and diverged to become highly host-adapted and host-specific pathogens. Two important virulence determinants played critical roles in this evolution: (i) a type IV secretion system that secretes effector molecules into the host cell cytoplasm that direct the intracellular trafficking of the brucellae and modulate host immune responses and (ii) a lipopolysaccharide moiety which poorly stimulates host inflammatory responses. This review highlights what we presently know about how these and other virulence determinants contribute to Brucella pathogenesis. Gaining a better understanding of how the brucellae produce disease will provide us with information that can be used to design better strategies for preventing brucellosis in animals and for preventing and treating this disease in humans.
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Affiliation(s)
- R Martin Roop
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
| | - Ian S Barton
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
| | - Dariel Hopersberger
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
| | - Daniel W Martin
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
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19
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The extracellular juncture domains in the intimin passenger adopt a constitutively extended conformation inducing restraints to its sphere of action. Sci Rep 2020; 10:21249. [PMID: 33277518 PMCID: PMC7718877 DOI: 10.1038/s41598-020-77706-7] [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: 07/14/2020] [Accepted: 11/05/2020] [Indexed: 02/06/2023] Open
Abstract
Enterohemorrhagic and enteropathogenic Escherichia coli are among the most important food-borne pathogens, posing a global health threat. The virulence factor intimin is essential for the attachment of pathogenic E. coli to the intestinal host cell. Intimin consists of four extracellular bacterial immunoglobulin-like (Big) domains, D00–D2, extending into the fifth lectin subdomain (D3) that binds to the Tir-receptor on the host cell. Here, we present the crystal structures of the elusive D00–D0 domains at 1.5 Å and D0–D1 at 1.8 Å resolution, which confirms that the passenger of intimin has five distinct domains. We describe that D00–D0 exhibits a higher degree of rigidity and D00 likely functions as a juncture domain at the outer membrane-extracellular medium interface. We conclude that D00 is a unique Big domain with a specific topology likely found in a broad range of other inverse autotransporters. The accumulated data allows us to model the complete passenger of intimin and propose functionality to the Big domains, D00–D0–D1, extending directly from the membrane.
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20
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Bialer MG, Sycz G, Muñoz González F, Ferrero MC, Baldi PC, Zorreguieta A. Adhesins of Brucella: Their Roles in the Interaction with the Host. Pathogens 2020; 9:E942. [PMID: 33198223 PMCID: PMC7697752 DOI: 10.3390/pathogens9110942] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 11/03/2020] [Accepted: 11/05/2020] [Indexed: 01/30/2023] Open
Abstract
A central aspect of Brucella pathogenicity is its ability to invade, survive, and replicate in diverse phagocytic and non-phagocytic cell types, leading to chronic infections and chronic inflammatory phenomena. Adhesion to the target cell is a critical first step in the invasion process. Several Brucella adhesins have been shown to mediate adhesion to cells, extracellular matrix components (ECM), or both. These include the sialic acid-binding proteins SP29 and SP41 (binding to erythrocytes and epithelial cells, respectively), the BigA and BigB proteins that contain an Ig-like domain (binding to cell adhesion molecules in epithelial cells), the monomeric autotransporters BmaA, BmaB, and BmaC (binding to ECM components, epithelial cells, osteoblasts, synoviocytes, and trophoblasts), the trimeric autotransporters BtaE and BtaF (binding to ECM components and epithelial cells) and Bp26 (binding to ECM components). An in vivo role has also been shown for the trimeric autotransporters, as deletion mutants display decreased colonization after oral and/or respiratory infection in mice, and it has also been suggested for BigA and BigB. Several adhesins have shown unipolar localization, suggesting that Brucella would express an adhesive pole. Adhesin-based vaccines may be useful to prevent brucellosis, as intranasal immunization in mice with BtaF conferred high levels of protection against oral challenge with B. suis.
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Affiliation(s)
- Magalí G. Bialer
- Fundación Instituto Leloir (FIL), IIBBA (CONICET-FIL), Buenos Aires 1405, Argentina; (M.G.B.); (G.S.)
| | - Gabriela Sycz
- Fundación Instituto Leloir (FIL), IIBBA (CONICET-FIL), Buenos Aires 1405, Argentina; (M.G.B.); (G.S.)
| | - Florencia Muñoz González
- Cátedra de Inmunología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires 1113, Argentina; (F.M.G.); (M.C.F.)
- Instituto de Estudios de la Inmunidad Humoral (IDEHU), CONICET-Universidad de Buenos Aires, Buenos Aires 1113, Argentina
| | - Mariana C. Ferrero
- Cátedra de Inmunología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires 1113, Argentina; (F.M.G.); (M.C.F.)
- Instituto de Estudios de la Inmunidad Humoral (IDEHU), CONICET-Universidad de Buenos Aires, Buenos Aires 1113, Argentina
| | - Pablo C. Baldi
- Cátedra de Inmunología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires 1113, Argentina; (F.M.G.); (M.C.F.)
- Instituto de Estudios de la Inmunidad Humoral (IDEHU), CONICET-Universidad de Buenos Aires, Buenos Aires 1113, Argentina
| | - Angeles Zorreguieta
- Fundación Instituto Leloir (FIL), IIBBA (CONICET-FIL), Buenos Aires 1405, Argentina; (M.G.B.); (G.S.)
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires 1428, Argentina
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21
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Lopez P, Guaimas F, Czibener C, Ugalde JE. A genomic island in Brucella involved in the adhesion to host cells: Identification of a new adhesin and a translocation factor. Cell Microbiol 2020; 22:e13245. [PMID: 32657513 DOI: 10.1111/cmi.13245] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 06/30/2020] [Accepted: 07/06/2020] [Indexed: 02/06/2023]
Abstract
Adhesion to host cells is the first step in the virulence cycle of any pathogen. In Gram-negative bacteria, adhesion is mediated, among other virulence factors such as the lipopolysaccharides, by specific outer-membrane proteins generally termed adhesins that belong to a wide variety of families and have different evolutionary origins. In Brucella, a widespread zoonotic pathogen of animal and human health concern, adhesion is central as it may determine the intracellular fate of the bacterium, an essential stage in its pathogenesis. In the present paper, we further characterised a genomic locus that we have previously reported encodes an adhesin (BigA) with a bacterial immunoglobulin-like domain (BIg-like). We found that this region encodes a second adhesin, which we have named BigB; and PalA, a periplasmic protein necessary for the proper display in the outer membrane of BigA and BigB. Deletion of bigB or palA diminishes the adhesion of the bacterium and overexpression of BigB dramatically increases it. Incubation of cells with the recombinant BIg-like domain of BigB induced important cytoskeletal rearrangements and affected the focal adhesion sites indicating that the adhesin targets cell-cell or cell-matrix proteins. We additionally show that PalA has a periplasmic localisation and is completely necessary for the proper display of BigA and BigB, probably avoiding their aggregation and facilitating their transport to the outer membrane. Our results indicate that this genomic island is entirely devoted to the adhesion of Brucella to host cells.
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Affiliation(s)
- Paula Lopez
- Instituto de Investigaciones Biotecnológicas 'Dr. Rodolfo A. Ugalde', IIB-UNSAM, IIBIO-CONICET, Universidad Nacional de San Martín, Buenos Aires, Argentina
| | - Francisco Guaimas
- Instituto de Investigaciones Biotecnológicas 'Dr. Rodolfo A. Ugalde', IIB-UNSAM, IIBIO-CONICET, Universidad Nacional de San Martín, Buenos Aires, Argentina
| | - Cecilia Czibener
- Instituto de Investigaciones Biotecnológicas 'Dr. Rodolfo A. Ugalde', IIB-UNSAM, IIBIO-CONICET, Universidad Nacional de San Martín, Buenos Aires, Argentina
| | - Juan E Ugalde
- Instituto de Investigaciones Biotecnológicas 'Dr. Rodolfo A. Ugalde', IIB-UNSAM, IIBIO-CONICET, Universidad Nacional de San Martín, Buenos Aires, Argentina
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22
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Whelan R, McVicker G, Leo JC. Staying out or Going in? The Interplay between Type 3 and Type 5 Secretion Systems in Adhesion and Invasion of Enterobacterial Pathogens. Int J Mol Sci 2020; 21:E4102. [PMID: 32521829 PMCID: PMC7312957 DOI: 10.3390/ijms21114102] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 06/03/2020] [Accepted: 06/05/2020] [Indexed: 12/12/2022] Open
Abstract
Enteric pathogens rely on a variety of toxins, adhesins and other virulence factors to cause infections. Some of the best studied pathogens belong to the Enterobacterales order; these include enteropathogenic and enterohemorrhagic Escherichia coli, Shigella spp., and the enteropathogenic Yersiniae. The pathogenesis of these organisms involves two different secretion systems, a type 3 secretion system (T3SS) and type 5 secretion systems (T5SSs). The T3SS forms a syringe-like structure spanning both bacterial membranes and the host cell plasma membrane that translocates toxic effector proteins into the cytoplasm of the host cell. T5SSs are also known as autotransporters, and they export part of their own polypeptide to the bacterial cell surface where it exerts its function, such as adhesion to host cell receptors. During infection with these enteropathogens, the T3SS and T5SS act in concert to bring about rearrangements of the host cell cytoskeleton, either to invade the cell, confer intracellular motility, evade phagocytosis or produce novel structures to shelter the bacteria. Thus, in these bacteria, not only the T3SS effectors but also T5SS proteins could be considered "cytoskeletoxins" that bring about profound alterations in host cell cytoskeletal dynamics and lead to pathogenic outcomes.
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Affiliation(s)
| | | | - Jack C. Leo
- Antimicrobial Resistance, Omics and Microbiota Group, Department of Biosciences, Nottingham Trent University, Nottingham NG1 4FQ, UK; (R.W.); (G.M.)
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23
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Wrobel A, Saragliadis A, Pérez-Ortega J, Sittman C, Göttig S, Liskiewicz K, Spence MH, Schneider K, Leo JC, Arenas J, Linke D. The inverse autotransporters of Yersinia ruckeri, YrInv and YrIlm, contribute to biofilm formation and virulence. Environ Microbiol 2020; 22:2939-2955. [PMID: 32372498 DOI: 10.1111/1462-2920.15051] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 04/27/2020] [Accepted: 04/27/2020] [Indexed: 11/28/2022]
Abstract
Yersinia ruckeri causes enteric redmouth disease (ERM) that mainly affects salmonid fishes and leads to significant economic losses in the aquaculture industry. An increasing number of outbreaks and the lack of effective vaccines against some serotypes necessitates novel measures to control ERM. Importantly, Y. ruckeri survives in the environment for long periods, presumably by forming biofilms. How the pathogen forms biofilms and which molecular factors are involved in this process, remains unclear. Yersinia ruckeri produces two surface-exposed adhesins, belonging to the inverse autotransporters (IATs), called Y. ruckeri invasin (YrInv) and Y. ruckeri invasin-like molecule (YrIlm). Here, we investigated whether YrInv and YrIlm play a role in biofilm formation and virulence. Functional assays revealed that YrInv and YrIlm promote biofilm formation on different abiotic substrates. Confocal microscopy revealed that they are involved in microcolony interaction and formation, respectively. The effect of both IATs on biofilm formation correlated with the presence of different biopolymers in the biofilm matrix, including extracellular DNA, RNA and proteins. Moreover, YrInv and YrIlm contributed to virulence in the Galleria mellonella infection model. Taken together, we propose that both IATs are possible targets for the development of novel diagnostic and preventative strategies to control ERM.
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Affiliation(s)
- Agnieszka Wrobel
- Department of Biosciences, University of Oslo, 0316, Oslo, Norway
| | | | - Jesús Pérez-Ortega
- Department of Molecular Microbiology and Institute of Biomembranes, Utrecht University, Utrecht, The Netherlands
| | - Carolin Sittman
- Institute of Medical Microbiology and Infection Control, Hospital of Johann Wolfgang Goethe-University, Frankfurt am Main, Germany
| | - Stephan Göttig
- Institute of Medical Microbiology and Infection Control, Hospital of Johann Wolfgang Goethe-University, Frankfurt am Main, Germany
| | | | | | | | - Jack C Leo
- Department of Biosciences, University of Oslo, 0316, Oslo, Norway.,Department of Biosciences, School of Science and Technology, Nottingham Trent University, Nottingham, NG1 4FQ, UK
| | - Jesús Arenas
- Department of Molecular Microbiology and Institute of Biomembranes, Utrecht University, Utrecht, The Netherlands.,Unit of Microbiology of the Department of Animal Pathology, University of Zaragoza, Zaragoza, Spain
| | - Dirk Linke
- Department of Biosciences, University of Oslo, 0316, Oslo, Norway
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24
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Han Y, Wei L, Xiao J, Zhang Y, Wang Q, Zhou M. Identification and study of InV as an inverse autotransporter family representative in Edwardsiella piscicida. Arch Microbiol 2020; 202:1107-1116. [PMID: 32052095 PMCID: PMC7223825 DOI: 10.1007/s00203-019-01804-y] [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] [Received: 02/25/2019] [Revised: 12/17/2019] [Accepted: 12/26/2019] [Indexed: 12/15/2022]
Abstract
Invasins and intimins, members of virulence-related adhesin family which is involved in attachment and adherence to epithelial cells during infection, are found in various pathogens. These pathogens can attach to enterocytes and lead to the formation of a pedestal-like structure. Invasins and intimins belong to type Ve secretion systems, and the N-terminal β-barrel domain acts as a translocation pore to secrete the C-terminal passenger domain. However, the relationship between invasins/intimins and type III secretion system (T3SS) has been poorly studied. Based on the transposon insertion mutant library of Edwardsiella piscicida, we got a transposon insertion mutant with significant T3SS defect and identified the mutated gene ETAE_0323 (named inV later). This gene encoded a protein with 2359 amino acid residues and was predicted to be an invasin. To study the relationship between InV and T3SS, strains with N-terminus or C-terminus deleted InV fragments were made. However, none of them was able to copy the phenotype of the transposon insertion mutant previously identified. The localization of InV in ΔT3SS strain was not significantly different from WT, suggesting that the T3SS defect in the transposon insertion mutant was likely to be caused by polar effect. Nevertheless, depletion of inV still showed dramatic internalization and virulence defect in HeLa cell and zebrafish model, respectively, suggesting InV as a virulence related protein.
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Affiliation(s)
- Yu Han
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, China
| | - Lifan Wei
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, China
| | - Jingfan Xiao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, China
| | - Yuanxing Zhang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, China.,Shanghai Collaborative Innovation Center for Biomanufacturing, 130 Meilong Road, Shanghai, 200237, China.,Shanghai Engineering Research Center of Maricultured Animal Vaccines, Shanghai, China
| | - Qiyao Wang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, China. .,Shanghai Collaborative Innovation Center for Biomanufacturing, 130 Meilong Road, Shanghai, 200237, China. .,Shanghai Engineering Research Center of Maricultured Animal Vaccines, Shanghai, China.
| | - Mian Zhou
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, China.
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25
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Gardette M, Le Hello S, Mariani-Kurkdjian P, Fabre L, Gravey F, Garrivier A, Loukiadis E, Jubelin G. Identification and prevalence of in vivo-induced genes in enterohaemorrhagic Escherichia coli. Virulence 2019; 10:180-193. [PMID: 30806162 PMCID: PMC6550539 DOI: 10.1080/21505594.2019.1582976] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 01/25/2019] [Accepted: 02/06/2019] [Indexed: 12/14/2022] Open
Abstract
Enterohaemorrhagic Escherichia coli (EHEC) are food-borne pathogens responsible for bloody diarrhoea and renal failure in humans. While Shiga toxin (Stx) is the cardinal virulence factor of EHEC, its production by E. coli is not sufficient to cause disease and many Shiga-toxin producing E. coli (STEC) strains have never been implicated in human infection. So far, the pathophysiology of EHEC infection is not fully understood and more knowledge is needed to characterize the "auxiliary" factors that enable a STEC strain to cause disease in humans. In this study, we applied a recombinase-based in vivo expression technology (RIVET) to the EHEC reference strain EDL933 in order to identify genes specifically induced during the infectious process, using mouse as an infection model. We identified 31 in vivo-induced (ivi) genes having functions related to metabolism, stress adaptive response and bacterial virulence or fitness. Eight of the 31 ivi genes were found to be heterogeneously distributed in EHEC strains circulating in France these last years. In addition, they are more prevalent in strains from the TOP seven priority serotypes and particularly strains carrying significant virulence determinants such as Stx2 and intimin adhesin. This work sheds further light on bacterial determinants over-expressed in vivo during infection that may contribute to the potential of STEC strains to cause disease in humans.
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Affiliation(s)
- Marion Gardette
- UCA, INRA, UMR454 MEDIS, Clermont-Ferrand, France
- Laboratoire d’écologie microbienne de Lyon, Université de Lyon, CNRS, INRA, UCBL, VetAgro Sup, Marcy l’Etoile, France
| | - Simon Le Hello
- Centre de Référence National des Escherichia coli, Shigella et Salmonella, Institut Pasteur, Paris, France
- Université de Normandie, EA 2656 GRAM 2.0, UNICAEN, Caen, France
| | - Patricia Mariani-Kurkdjian
- Service de Microbiologie, Centre National de Référence associé Escherichia coli, Hôpital Robert-Debré, AP-HP, Paris, France
| | - Laetitia Fabre
- Centre de Référence National des Escherichia coli, Shigella et Salmonella, Institut Pasteur, Paris, France
| | - François Gravey
- Centre de Référence National des Escherichia coli, Shigella et Salmonella, Institut Pasteur, Paris, France
- Université de Normandie, EA 2656 GRAM 2.0, UNICAEN, Caen, France
| | | | - Estelle Loukiadis
- Laboratoire d’écologie microbienne de Lyon, Université de Lyon, CNRS, INRA, UCBL, VetAgro Sup, Marcy l’Etoile, France
- Laboratoire national de référence des E. coli, Université de Lyon, VetAgro Sup, Marcy l’Etoile, France
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26
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Utilizing Whole Fusobacterium Genomes To Identify, Correct, and Characterize Potential Virulence Protein Families. J Bacteriol 2019; 201:JB.00273-19. [PMID: 31501282 DOI: 10.1128/jb.00273-19] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 09/03/2019] [Indexed: 12/20/2022] Open
Abstract
Fusobacterium spp. are Gram-negative, anaerobic, opportunistic pathogens involved in multiple diseases, including a link between the oral pathogen Fusobacterium nucleatum and the progression and severity of colorectal cancer. The identification and characterization of virulence factors in the genus Fusobacterium has been greatly hindered by a lack of properly assembled and annotated genomes. Using newly completed genomes from nine strains and seven species of Fusobacterium, we report the identification and corrected annotation of verified and potential virulence factors from the type 5 secreted autotransporter, FadA, and MORN2 protein families, with a focus on the genetically tractable strain F. nucleatum subsp. nucleatum ATCC 23726 and type strain F. nucleatum subsp. nucleatum ATCC 25586. Within the autotransporters, we used sequence similarity networks to identify protein subsets and show a clear differentiation between the prediction of outer membrane adhesins, serine proteases, and proteins with unknown function. These data have identified unique subsets of type 5a autotransporters, which are key proteins associated with virulence in F. nucleatum However, we coupled our bioinformatic data with bacterial binding assays to show that a predicted weakly invasive strain of F. necrophorum that lacks a Fap2 autotransporter adhesin strongly binds human colonocytes. These analyses confirm a gap in our understanding of how autotransporters, MORN2 domain proteins, and FadA adhesins contribute to host interactions and invasion. In summary, we identify candidate virulence genes in Fusobacterium, and caution that experimental validation of host-microbe interactions should complement bioinformatic predictions to increase our understanding of virulence protein contributions in Fusobacterium infections and disease.IMPORTANCE Fusobacterium spp. are emerging pathogens that contribute to mammalian and human diseases, including colorectal cancer. Despite a validated connection with disease, few proteins have been characterized that define a direct molecular mechanism for Fusobacterium pathogenesis. We report a comprehensive examination of virulence-associated protein families in multiple Fusobacterium species and show that complete genomes facilitate the correction and identification of multiple, large type 5a secreted autotransporter genes in previously misannotated or fragmented genomes. In addition, we use protein sequence similarity networks and human cell interaction experiments to show that previously predicted noninvasive strains can indeed bind to and potentially invade human cells and that this could be due to the expansion of specific virulence proteins that drive Fusobacterium infections and disease.
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27
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Wrobel A, Leo JC, Linke D. Overcoming Fish Defences: The Virulence Factors of Yersinia ruckeri. Genes (Basel) 2019; 10:E700. [PMID: 31514317 PMCID: PMC6770984 DOI: 10.3390/genes10090700] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Revised: 09/02/2019] [Accepted: 09/05/2019] [Indexed: 12/24/2022] Open
Abstract
Yersinia ruckeri is the causative agent of enteric redmouth disease, a bacterial infection of marine and freshwater fish. The disease mainly affects salmonids, and outbreaks have significant economic impact on fish farms all over the world. Vaccination routines are in place against the major serotypes of Y. ruckeri but are not effective in all cases. Despite the economic importance of enteric redmouth disease, a detailed molecular understanding of the disease is lacking. A considerable number of mostly omics-based studies have been performed in recent years to identify genes related to Y. ruckeri virulence. This review summarizes the knowledge on Y. ruckeri virulence factors. Understanding the molecular pathogenicity of Y. ruckeri will aid in developing more efficient vaccines and antimicrobial compounds directed against enteric redmouth disease.
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Affiliation(s)
- Agnieszka Wrobel
- Department of Biosciences, University of Oslo, 0316 Oslo, Norway.
| | - Jack C Leo
- Department of Biosciences, University of Oslo, 0316 Oslo, Norway.
- Department of Biosciences, School of Science and Technology, Nottingham Trent University, Nottingham NG1 4FQ, UK.
| | - Dirk Linke
- Department of Biosciences, University of Oslo, 0316 Oslo, Norway.
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28
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Abstract
Escherichia coli is one of the most prevalent facultative anaerobes of the human gut. E. coli normally exists as a harmless commensal but can also cause disease following the acquisition of genes that enhance its pathogenicity. Adhesion is an important first step in colonization of the host and is mediated by an array of cell surface components. In E. coli, these include a family of adhesins secreted by the type V secretion system. Here, we identified and characterized new proteins from an emerging subclass of the type V secretion system known as the inverse autotransporters (IATs). We found that IAT-encoding genes are present in a wide range of strains and showed that three novel IATs were localized on the E. coli cell surface and mediated biofilm formation. Overall, this study provides new insight into the prevalence, function, and regulation of IATs in E. coli. Proteins secreted by the type V secretion system possess multiple functions, including the capacity to mediate adhesion, aggregation, and biolfilm formation. The type V secretion system can be divided into five subclasses, one of which is the type Ve system. Proteins of the type Ve secretion system are also referred to as inverse autotransporters (IATs). In this study, we performed an in silico analysis of 126 completely sequenced Escherichia coli genomes available in the NCBI database and identified several distinct IAT-encoding gene families whose distribution varied throughout the E. coli phylogeny. The genes included three characterized IATs (intimin, fdeC, and yeeJ) and four uncharacterized IATs (here named iatA, iatB, iatC, and iatD). The four iat genes were cloned from the completely sequenced environmental E. coli strain SMS-3-5 and characterized. Three of these IAT proteins (IatB, IatC, and IatD) were expressed at the cell surface and possessed the capacity to mediate biofilm formation in a recombinant E. coli K-12 strain. Further analysis of the iatB gene, which showed a unique association with extraintestinal E. coli strains, suggested that its regulation is controlled by the LeuO global regulator. Overall, this study provides new data describing the prevalence, sequence variation, domain structure, function, and regulation of IATs found in E. coli. IMPORTANCEEscherichia coli is one of the most prevalent facultative anaerobes of the human gut. E. coli normally exists as a harmless commensal but can also cause disease following the acquisition of genes that enhance its pathogenicity. Adhesion is an important first step in colonization of the host and is mediated by an array of cell surface components. In E. coli, these include a family of adhesins secreted by the type V secretion system. Here, we identified and characterized new proteins from an emerging subclass of the type V secretion system known as the inverse autotransporters (IATs). We found that IAT-encoding genes are present in a wide range of strains and showed that three novel IATs were localized on the E. coli cell surface and mediated biofilm formation. Overall, this study provides new insight into the prevalence, function, and regulation of IATs in E. coli.
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29
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Leibiger K, Schweers JM, Schütz M. Biogenesis and function of the autotransporter adhesins YadA, intimin and invasin. Int J Med Microbiol 2019; 309:331-337. [PMID: 31176600 DOI: 10.1016/j.ijmm.2019.05.009] [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: 12/20/2018] [Revised: 05/06/2019] [Accepted: 05/31/2019] [Indexed: 01/15/2023] Open
Abstract
Bacteria often express numerous virulence factors. These virulence factors make them successful pathogens, by e.g. mediating attachment to host cells and thereby facilitating persistence or invasion, or by contributing to the evasion of the host immune system to allow proliferation and spread within the host and in the environment. The site of first contact of Gram negative bacteria with the host is the bacterial outer membrane (OM). Consisting of an asymmetrical lipid bilayer with phospholipids forming the inner, and lipopolysaccharides forming the outer leaflet, the OM harbors numerous integral membrane proteins that are almost exclusively β-barrel proteins. One distinct family of OM β-barrel proteins strongly linked to bacterial virulence are the autotransporter (AT) proteins. During the last years huge progress has been made to better understand the mechanisms underlying the insertion of AT proteins into the OM and also AT function for interaction with the host. This review shortly summarizes our current knowledge about outer membrane protein (OMP) and more specifically AT biogenesis and function. We focused on the AT proteins that we haved studied in most detail: i.e. the Yersinia adhesin A (YadA) and invasin of Yersinia enterocolitica (Ye) as well as its homolog intimin (Int) expressed by enteropathogenic Escherichia coli. In addition, this review provides a short outlook about how we could possibly use this knowledge to fight infection.
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Affiliation(s)
- Karolin Leibiger
- Institut für Medizinische Mikrobiologie und Hygiene, Elfriede-Aulhorn-Str. 6, 72076, Tübingen, Germany
| | - Jonas Malte Schweers
- Institut für Medizinische Mikrobiologie und Hygiene, Elfriede-Aulhorn-Str. 6, 72076, Tübingen, Germany
| | - Monika Schütz
- Institut für Medizinische Mikrobiologie und Hygiene, Elfriede-Aulhorn-Str. 6, 72076, Tübingen, Germany.
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30
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Meuskens I, Saragliadis A, Leo JC, Linke D. Type V Secretion Systems: An Overview of Passenger Domain Functions. Front Microbiol 2019; 10:1163. [PMID: 31214135 PMCID: PMC6555100 DOI: 10.3389/fmicb.2019.01163] [Citation(s) in RCA: 93] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 05/07/2019] [Indexed: 12/12/2022] Open
Abstract
Bacteria secrete proteins for different purposes such as communication, virulence functions, adhesion to surfaces, nutrient acquisition, or growth inhibition of competing bacteria. For secretion of proteins, Gram-negative bacteria have evolved different secretion systems, classified as secretion systems I through IX to date. While some of these systems consist of multiple proteins building a complex spanning the cell envelope, the type V secretion system, the subject of this review, is rather minimal. Proteins of the Type V secretion system are often called autotransporters (ATs). In the simplest case, a type V secretion system consists of only one polypeptide chain with a β-barrel translocator domain in the membrane, and an extracellular passenger or effector region. Depending on the exact domain architecture of the protein, type V secretion systems can be further separated into sub-groups termed type Va through e, and possibly another recently identified subtype termed Vf. While this classification works well when it comes to the architecture of the proteins, this is not the case for the function(s) of the secreted passenger. In this review, we will give an overview of the functions of the passengers of the different AT classes, shedding more light on the variety of functions carried out by type V secretion systems.
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Affiliation(s)
| | | | | | - Dirk Linke
- Department of Biosciences, Section for Genetics and Evolutionary Biology, University of Oslo, Oslo, Norway
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31
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Hatlem D, Trunk T, Linke D, Leo JC. Catching a SPY: Using the SpyCatcher-SpyTag and Related Systems for Labeling and Localizing Bacterial Proteins. Int J Mol Sci 2019; 20:E2129. [PMID: 31052154 PMCID: PMC6539128 DOI: 10.3390/ijms20092129] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 04/25/2019] [Accepted: 04/26/2019] [Indexed: 01/05/2023] Open
Abstract
The SpyCatcher-SpyTag system was developed seven years ago as a method for protein ligation. It is based on a modified domain from a Streptococcus pyogenes surface protein (SpyCatcher), which recognizes a cognate 13-amino-acid peptide (SpyTag). Upon recognition, the two form a covalent isopeptide bond between the side chains of a lysine in SpyCatcher and an aspartate in SpyTag. This technology has been used, among other applications, to create covalently stabilized multi-protein complexes, for modular vaccine production, and to label proteins (e.g., for microscopy). The SpyTag system is versatile as the tag is a short, unfolded peptide that can be genetically fused to exposed positions in target proteins; similarly, SpyCatcher can be fused to reporter proteins such as GFP, and to epitope or purification tags. Additionally, an orthogonal system called SnoopTag-SnoopCatcher has been developed from an S. pneumoniae pilin that can be combined with SpyCatcher-SpyTag to produce protein fusions with multiple components. Furthermore, tripartite applications have been produced from both systems allowing the fusion of two peptides by a separate, catalytically active protein unit, SpyLigase or SnoopLigase. Here, we review the current state of the SpyCatcher-SpyTag and related technologies, with a particular emphasis on their use in vaccine development and in determining outer membrane protein localization and topology of surface proteins in bacteria.
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Affiliation(s)
- Daniel Hatlem
- Bacterial Cell Surface Group, Section for Evolution and Genetics, Department of Biosciences, University of Oslo, 0316 Oslo, Norway.
| | - Thomas Trunk
- Bacterial Cell Surface Group, Section for Evolution and Genetics, Department of Biosciences, University of Oslo, 0316 Oslo, Norway.
| | - Dirk Linke
- Bacterial Cell Surface Group, Section for Evolution and Genetics, Department of Biosciences, University of Oslo, 0316 Oslo, Norway.
| | - Jack C Leo
- Bacterial Cell Surface Group, Section for Evolution and Genetics, Department of Biosciences, University of Oslo, 0316 Oslo, Norway.
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32
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Abstract
Type V, or "autotransporter," secretion is a term used to refer to several simple protein export pathways that are found in a wide range of Gram-negative bacteria. Autotransporters are generally single polypeptides that consist of an extracellular ("passenger") domain and a β barrel domain that anchors the protein to the outer membrane (OM). Although it was originally proposed that the passenger domain is secreted through a channel formed solely by the covalently linked β barrel domain, experiments performed primarily on the type Va, or "classical," autotransporter pathway have challenged this hypothesis. Several lines of evidence strongly suggest that both the secretion of the passenger domain and the membrane integration of the β barrel domain are catalyzed by the barrel assembly machinery (Bam) complex, a conserved hetero-oligomer that plays an essential role in the assembly of most integral OM proteins. The secretion reaction appears to be driven at least in part by the folding of the passenger domain in the extracellular space. Although many aspects of autotransporter biogenesis remain to be elucidated, it will be especially interesting to determine whether the different classes of proteins that fall under the type V rubric-most of which have not been examined in detail-are assembled by the same basic mechanism as classical autotransporters.
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33
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Leo JC, Linke D. A unified model for BAM function that takes into account type Vc secretion and species differences in BAM composition. AIMS Microbiol 2018; 4:455-468. [PMID: 31294227 PMCID: PMC6604945 DOI: 10.3934/microbiol.2018.3.455] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 06/13/2018] [Indexed: 01/14/2023] Open
Abstract
Transmembrane proteins in the outer membrane of Gram-negative bacteria are almost exclusively β-barrels. They are inserted into the outer membrane by a conserved and essential protein complex called the BAM (for β-barrel assembly machinery). In this commentary, we summarize current research into the mechanism of this protein complex and how it relates to type V secretion. Type V secretion systems are autotransporters that all contain a β-barrel transmembrane domain inserted by BAM. In type Vc systems, this domain is a homotrimer. We argue that none of the current models are sufficient to explain BAM function particularly regarding type Vc secretion. We also find that current models based on the well-studied model system Escherichia coli mostly ignore the pronounced differences in BAM composition between different bacterial species. We propose a more holistic view on how all OMPs, including autotransporters, are incorporated into the lipid bilayer.
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Affiliation(s)
- Jack C Leo
- Department of Biosciences, University of Oslo, Blindernveien 31, 0316 Oslo, Norway
| | - Dirk Linke
- Department of Biosciences, University of Oslo, Blindernveien 31, 0316 Oslo, Norway
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34
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Direct Manipulation of T Lymphocytes by Proteins of Gastrointestinal Bacterial Pathogens. Infect Immun 2018; 86:IAI.00683-17. [PMID: 29339462 DOI: 10.1128/iai.00683-17] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Gastrointestinal bacterial infection represents a significant threat to human health, as well as a burden on food animal production and welfare. Although there is advanced knowledge about the molecular mechanisms underlying pathogenesis, including the development of immune responses to these pathogens, gaps in knowledge persist. It is well established that gastrointestinal bacterial pathogens produce a myriad of proteins that affect the development and effectiveness of innate immune responses. However, relatively few proteins that directly affect lymphocytes responsible for humoral or cell-mediated immunity and memory have been identified. Here, we review factors produced by gastrointestinal bacterial pathogens that have direct T cell interactions and what is known about their functions and mechanisms of action. T cell-interacting bacterial proteins that have been identified to date mainly target three major T cell responses: activation and expansion, chemotaxis, or apoptosis. Further, the requirement for more focused studies to identify and understand additional mechanisms used by bacteria to directly affect the T cell immune response and how these may contribute to pathogenesis is highlighted. Increased knowledge in this area will help to drive development of better interventions in prevention and treatment of gastrointestinal bacterial infection.
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35
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Elhosseiny NM, Attia AS. Acinetobacter: an emerging pathogen with a versatile secretome. Emerg Microbes Infect 2018; 7:33. [PMID: 29559620 PMCID: PMC5861075 DOI: 10.1038/s41426-018-0030-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 12/08/2017] [Accepted: 01/09/2018] [Indexed: 02/06/2023]
Abstract
Acinetobacter baumannii is a notorious pathogen that has emerged as a healthcare nightmare in recent years because it causes serious infections that are associated with high morbidity and mortality rates. Due to its exceptional ability to acquire resistance to almost all available antibiotics, A. baumannii is currently ranked as the first pathogen on the World Health Organization’s priority list for the development of new antibiotics. The versatile range of effectors secreted by A. baumannii represents a large proportion of the virulence arsenal identified in this bacterium to date. Thus, these factors, together with the secretory machinery responsible for their extrusion into the extracellular milieu, are key targets for novel therapeutics that are greatly needed to combat this deadly pathogen. In this review, we provide a comprehensive, up-to-date overview of the organization and regulatory aspects of the Acinetobacter secretion systems, with a special emphasis on their versatile substrates that could be targeted to fight the deadly infections caused by this elusive pathogen.
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Affiliation(s)
- Noha M Elhosseiny
- Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Cairo, 11562, Egypt
| | - Ahmed S Attia
- Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Cairo, 11562, Egypt.
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36
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Sadana P, Geyer R, Pezoldt J, Helmsing S, Huehn J, Hust M, Dersch P, Scrima A. The invasin D protein from Yersinia pseudotuberculosis selectively binds the Fab region of host antibodies and affects colonization of the intestine. J Biol Chem 2018. [PMID: 29535184 DOI: 10.1074/jbc.ra117.001068] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Yersinia pseudotuberculosis is a Gram-negative bacterium and zoonotic pathogen responsible for a wide range of diseases, ranging from mild diarrhea, enterocolitis, lymphatic adenitis to persistent local inflammation. The Y. pseudotuberculosis invasin D (InvD) molecule belongs to the invasin (InvA)-type autotransporter proteins, but its structure and function remain unknown. In this study, we present the first crystal structure of InvD, analyzed its expression and function in a murine infection model, and identified its target molecule in the host. We found that InvD is induced at 37 °C and expressed in vivo 2-4 days after infection, indicating that InvD is a virulence factor. During infection, InvD was expressed in all parts of the intestinal tract, but not in deeper lymphoid tissues. The crystal structure of the C-terminal adhesion domain of InvD revealed a distinct Ig-related fold that, apart from the canonical β-sheets, comprises various modifications of and insertions into the Ig-core structure. We identified the Fab fragment of host-derived IgG/IgA antibodies as the target of the adhesion domain. Phage display panning and flow cytometry data further revealed that InvD exhibits a preferential binding specificity toward antibodies with VH3/VK1 variable domains and that it is specifically recruited to a subset of B cells. This finding suggests that InvD modulates Ig functions in the intestine and affects direct interactions with a subset of cell surface-exposed B-cell receptors. In summary, our results provide extensive insights into the structure of InvD and its specific interaction with the target molecule in the host.
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Affiliation(s)
- Pooja Sadana
- From the Young Investigator Group Structural Biology of Autophagy, Department of Structure and Function of Proteins
| | | | - Joern Pezoldt
- Experimental Immunology, Helmholtz-Centre for Infection Research, 38124 Braunschweig and
| | - Saskia Helmsing
- the Institute of Biochemistry, Biotechnology and Bioinformatics, Technische Universität, 38106 Braunschweig, Germany
| | - Jochen Huehn
- Experimental Immunology, Helmholtz-Centre for Infection Research, 38124 Braunschweig and
| | - Michael Hust
- the Institute of Biochemistry, Biotechnology and Bioinformatics, Technische Universität, 38106 Braunschweig, Germany
| | - Petra Dersch
- the Departments of Molecular Infection Biology and
| | - Andrea Scrima
- From the Young Investigator Group Structural Biology of Autophagy, Department of Structure and Function of Proteins,
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37
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Salema V, Fernández LÁ. Escherichia coli surface display for the selection of nanobodies. Microb Biotechnol 2017; 10:1468-1484. [PMID: 28772027 PMCID: PMC5658595 DOI: 10.1111/1751-7915.12819] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 07/12/2017] [Accepted: 07/13/2017] [Indexed: 12/29/2022] Open
Abstract
Nanobodies (Nbs) are the smallest functional antibody fragments known in nature and have multiple applications in biomedicine or environmental monitoring. Nbs are derived from the variable segment of camelid heavy chain-only antibodies, known as VHH. For selection, libraries of VHH gene segments from naïve, immunized animals or of synthetic origin have been traditionally cloned in E. coli phage display or yeast display systems, and clones binding the target antigen recovered, usually from plastic surfaces with the immobilized antigen (phage display) or using fluorescence-activated cell sorting (FACS; yeast display). This review briefly describes these conventional approaches and focuses on the distinct properties of an E. coli display system developed in our laboratory, which combines the benefits of both phage display and yeast display systems. We demonstrate that E. coli display using an N-terminal domain of intimin is an effective platform for the surface display of VHH libraries enabling selection of high-affinity Nbs by magnetic cell sorting and direct selection on live mammalian cells displaying the target antigen on their surface. Flow cytometry analysis of E. coli bacteria displaying the Nbs on their surface allows monitoring of the selection process, facilitates screening, characterization of antigen-binding clones, specificity, ligand competition and estimation of the equilibrium dissociation constant (KD ).
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Affiliation(s)
- Valencio Salema
- Department of Microbial BiotechnologyCentro Nacional de Biotecnología (CNB)Consejo Superior de Investigaciones Científicas (CSIC)MadridSpain
| | - Luis Ángel Fernández
- Department of Microbial BiotechnologyCentro Nacional de Biotecnología (CNB)Consejo Superior de Investigaciones Científicas (CSIC)MadridSpain
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38
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Webb CT, Chandrapala D, Oslan SN, Bamert RS, Grinter RD, Dunstan RA, Gorrell RJ, Song J, Strugnell RA, Lithgow T, Kwok T. Reductive evolution in outer membrane protein biogenesis has not compromised cell surface complexity in Helicobacter pylori. Microbiologyopen 2017; 6. [PMID: 29055967 PMCID: PMC5727368 DOI: 10.1002/mbo3.513] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 05/19/2017] [Accepted: 05/25/2017] [Indexed: 12/18/2022] Open
Abstract
Helicobacter pylori is a gram‐negative bacterial pathogen that chronically inhabits the human stomach. To survive and maintain advantage, it has evolved unique host–pathogen interactions mediated by Helicobacter‐specific proteins in the bacterial outer membrane. These outer membrane proteins (OMPs) are anchored to the cell surface via a C‐terminal β‐barrel domain, which requires their assembly by the β‐barrel assembly machinery (BAM). Here we have assessed the complexity of the OMP C‐terminal β‐barrel domains employed by H. pylori, and characterized the H. pyloriBAM complex. Around 50 Helicobacter‐specific OMPs were assessed with predictive structural algorithms. The data suggest that H. pylori utilizes a unique β‐barrel architecture that might constitute H. pylori‐specific Type V secretions system. The structural and functional diversity in these proteins is encompassed by their extramembrane domains. Bioinformatic and biochemical characterization suggests that the low β‐barrel‐complexity requires only minimalist assembly machinery. The H. pylori proteins BamA and BamD associate to form a BAM complex, with features of BamA enabling an oligomerization that might represent a mechanism by which a minimalist BAM complex forms a larger, sophisticated machinery capable of servicing the outer membrane proteome of H. pylori.
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Affiliation(s)
- Chaille T. Webb
- Infection & Immunity ProgramBiomedicine Discovery Institute and Department of MicrobiologyMonash UniversityClaytonAustralia
| | - Dilini Chandrapala
- Infection & Immunity ProgramBiomedicine Discovery Institute and Department of MicrobiologyMonash UniversityClaytonAustralia
- Infection & Immunity ProgramBiomedicine Discovery Institute and Department of Biochemistry and Molecular BiologyMonash UniversityClaytonAustralia
| | - Siti Nurbaya Oslan
- Infection & Immunity ProgramBiomedicine Discovery Institute and Department of MicrobiologyMonash UniversityClaytonAustralia
- Department of BiochemistryFaculty of Biotechnology and Biomolecular SciencesUniversiti Putra MalaysiaSerdangSelangorMalaysia
- Enzyme and Microbial Technology Research CenterUniversiti Putra MalaysiaSerdangSelangorMalaysia
| | - Rebecca S. Bamert
- Infection & Immunity ProgramBiomedicine Discovery Institute and Department of MicrobiologyMonash UniversityClaytonAustralia
| | - Rhys D. Grinter
- Infection & Immunity ProgramBiomedicine Discovery Institute and Department of MicrobiologyMonash UniversityClaytonAustralia
| | - Rhys A. Dunstan
- Infection & Immunity ProgramBiomedicine Discovery Institute and Department of MicrobiologyMonash UniversityClaytonAustralia
| | - Rebecca J. Gorrell
- Infection & Immunity ProgramBiomedicine Discovery Institute and Department of MicrobiologyMonash UniversityClaytonAustralia
- Infection & Immunity ProgramBiomedicine Discovery Institute and Department of Biochemistry and Molecular BiologyMonash UniversityClaytonAustralia
| | - Jiangning Song
- Infection & Immunity ProgramBiomedicine Discovery Institute and Department of Biochemistry and Molecular BiologyMonash UniversityClaytonAustralia
- Monash Centre for Data ScienceFaculty of Information TechnologyMonash UniversityMelbourneAustralia
| | - Richard A. Strugnell
- Department of Microbiology & ImmunologyUniversity of MelbourneParkvilleAustralia
| | - Trevor Lithgow
- Infection & Immunity ProgramBiomedicine Discovery Institute and Department of MicrobiologyMonash UniversityClaytonAustralia
| | - Terry Kwok
- Infection & Immunity ProgramBiomedicine Discovery Institute and Department of MicrobiologyMonash UniversityClaytonAustralia
- Infection & Immunity ProgramBiomedicine Discovery Institute and Department of Biochemistry and Molecular BiologyMonash UniversityClaytonAustralia
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39
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Vo JL, Martínez Ortiz GC, Subedi P, Keerthikumar S, Mathivanan S, Paxman JJ, Heras B. Autotransporter Adhesins in Escherichia coli Pathogenesis. Proteomics 2017; 17. [PMID: 28665015 DOI: 10.1002/pmic.201600431] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Revised: 06/21/2017] [Indexed: 12/14/2022]
Abstract
Most bacteria produce adhesion molecules to facilitate the interaction with host cells and establish successful infections. An important group of bacterial adhesins belong to the autotransporter (AT) superfamily, the largest group of secreted and outer membrane proteins in Gram-negative bacteria. AT adhesins possess diverse functions that facilitate bacterial colonisation, survival and persistence, and as such are often associated with increased bacterial fitness and pathogenic potential. In this review, we will describe AIDA-I type AT adhesins, which comprise the biggest and most diverse group in the AT family. We will focus on Escherichia coli proteins and define general aspects of their biogenesis, distribution, structural properties and key roles in infection.
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Affiliation(s)
- Julieanne L Vo
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia
| | - Gabriela Constanza Martínez Ortiz
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia
| | - Pramod Subedi
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia
| | - Shivakumar Keerthikumar
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia
| | - Suresh Mathivanan
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia
| | - Jason J Paxman
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia
| | - Begoña Heras
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia
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40
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Albenne C, Ieva R. Job contenders: roles of the β-barrel assembly machinery and the translocation and assembly module in autotransporter secretion. Mol Microbiol 2017; 106:505-517. [PMID: 28887826 DOI: 10.1111/mmi.13832] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/07/2017] [Indexed: 01/17/2023]
Abstract
In Gram-negative bacteria, autotransporters secrete effector protein domains that are linked to virulence. Although they were once thought to be simple and autonomous secretion machines, mounting evidence reveals that multiple factors of the bacterial envelope are necessary for autotransporter assembly. Secretion across the outer membrane of their soluble effector "passenger domain" is promoted by the assembly of an outer membrane-spanning "β-barrel domain". Both reactions require BamA, an essential component of the β-barrel assembly machinery (BAM complex) that catalyzes the final reaction step by which outer membrane proteins are integrated into the lipid bilayer. A large amount of data generated in the last decade has shed key insights onto the mechanistic coordination of autotransporter β-barrel domain assembly and passenger domain secretion. These results, together with the recently solved structures of the BAM complex, offer an unprecedented opportunity to discuss a detailed model of autotransporter assembly. Importantly, some autotransporters benefit from the presence of an additional machinery, the translocation and assembly module (TAM), a two-membrane spanning complex, which contains a BamA-homologous subunit. Although it remains unclear how the BAM complex and the TAM cooperate, it is evident that multiple preparatory steps are necessary for efficient autotransporter biogenesis.
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Affiliation(s)
- Cécile Albenne
- Laboratoire de Microbiologie et de Génétique Moléculaires, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Raffaele Ieva
- Laboratoire de Microbiologie et de Génétique Moléculaires, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
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Martinez-Gil M, Goh KGK, Rackaityte E, Sakamoto C, Audrain B, Moriel DG, Totsika M, Ghigo JM, Schembri MA, Beloin C. YeeJ is an inverse autotransporter from Escherichia coli that binds to peptidoglycan and promotes biofilm formation. Sci Rep 2017; 7:11326. [PMID: 28900103 PMCID: PMC5595812 DOI: 10.1038/s41598-017-10902-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 08/16/2017] [Indexed: 02/08/2023] Open
Abstract
Escherichia coli is a commensal or pathogenic bacterium that can survive in diverse environments. Adhesion to surfaces is essential for E. coli colonization, and thus it is important to understand the molecular mechanisms that promote this process in different niches. Autotransporter proteins are a class of cell-surface factor used by E. coli for adherence. Here we characterized the regulation and function of YeeJ, a poorly studied but widespread representative from an emerging class of autotransporter proteins, the inverse autotransporters (IAT). We showed that the yeeJ gene is present in ~40% of 96 completely sequenced E. coli genomes and that YeeJ exists as two length variants, albeit with no detectable functional differences. We demonstrated that YeeJ promotes biofilm formation in different settings through exposition at the cell-surface. We also showed that YeeJ contains a LysM domain that interacts with peptidoglycan and thus assists its localization into the outer membrane. Additionally, we identified the Polynucleotide Phosphorylase PNPase as a repressor of yeeJ transcription. Overall, our work provides new insight into YeeJ as a member of the recently defined IAT class, and contributes to our understanding of how commensal and pathogenic E. coli colonise their environments.
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Affiliation(s)
- Marta Martinez-Gil
- Institut Pasteur, Unité de Génétique des Biofilms, 28 rue du Dr. Roux, 75724, Paris, CEDEX 15, France
- Departamento de Biología Celular, Genética y Fisiología, Facultad de Ciencias. Universidad de Málaga, Málaga, Spain
| | - Kelvin G K Goh
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Elze Rackaityte
- Institut Pasteur, Unité de Génétique des Biofilms, 28 rue du Dr. Roux, 75724, Paris, CEDEX 15, France
- University of California San Francisco, Department of Medicine, San Francisco, CA, USA
| | - Chizuko Sakamoto
- Institut Pasteur, Unité de Génétique des Biofilms, 28 rue du Dr. Roux, 75724, Paris, CEDEX 15, France
| | - Bianca Audrain
- Institut Pasteur, Unité de Génétique des Biofilms, 28 rue du Dr. Roux, 75724, Paris, CEDEX 15, France
| | - Danilo G Moriel
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD 4072, Australia
- GSK Vaccines Institute for Global Health S.r.l., 53100, Siena, Italy
| | - Makrina Totsika
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD 4072, Australia
- Institute of Health and Biomedical Innovation, and School of Biomedical Sciences, Queensland University of Technology, Kelvin Grove, QLD, 4059, Australia
| | - Jean-Marc Ghigo
- Institut Pasteur, Unité de Génétique des Biofilms, 28 rue du Dr. Roux, 75724, Paris, CEDEX 15, France
| | - Mark A Schembri
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia.
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD 4072, Australia.
| | - Christophe Beloin
- Institut Pasteur, Unité de Génétique des Biofilms, 28 rue du Dr. Roux, 75724, Paris, CEDEX 15, France.
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42
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Wrobel A, Ottoni C, Leo JC, Gulla S, Linke D. The repeat structure of two paralogous genes, Yersinia ruckeri invasin (yrInv) and a "Y. ruckeri invasin-like molecule", (yrIlm) sheds light on the evolution of adhesive capacities of a fish pathogen. J Struct Biol 2017; 201:171-183. [PMID: 28888816 DOI: 10.1016/j.jsb.2017.08.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 08/18/2017] [Accepted: 08/28/2017] [Indexed: 11/18/2022]
Abstract
Inverse autotransporters comprise the recently identified type Ve secretion system and are exemplified by intimin from enterohaemorrhagic Escherichia coli and invasin from enteropathogenic Yersiniae. These proteins share a common domain architecture and promote bacterial adhesion to host cells. Here, we identified and characterized two putative inverse autotransporter genes in the fish pathogen Yersinia ruckeri NVH_3758, namely yrInv (for Y. ruckeri invasin) and yrIlm (for Y. ruckeri invasin-like molecule). When trying to clone the highly repetitive genes for structural and functional studies, we experienced problems in obtaining PCR products. PCR failures and the highly repetitive nature of inverse autotransporters prompted us to sequence the genome of Y. ruckeri NVH_3758 using PacBio sequencing, which produces some of the longest average read lengths available in the industry at this moment. According to our sequencing data, YrIlm is composed of 2603 amino acids (7812bp) and has a molecular mass of 256.4kDa. Based on the new genome information, we performed PCR analysis on four non-sequenced Y. ruckeri strains as well as the sequenced. Y. ruckeri type strain. We found that the genes are variably present in the strains, and that the length of yrIlm, when present, also varies. In addition, the length of the gene product for all strains, including the type strain, was much longer than expected based on deposited sequences. The internal repeats of the yrInv gene product are highly diverged, but represent the same bacterial immunoglobulin-like domains as in yrIlm. Using qRT-PCR, we found that yrIlm and yrInv are differentially expressed under conditions relevant for pathogenesis. In addition, we compared the genomic context of both genes in the newly sequenced Y. ruckeri strain to all available PacBio-sequenced Y. ruckeri genomes, and found indications of recent events of horizontal gene transfer. Taken together, this study demonstrates and highlights the power of Single Molecule Real-Time technology for sequencing highly repetitive proteins, and sheds light on the genetic events that gave rise to these highly repetitive genes in a commercially important fish pathogen.
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Affiliation(s)
- Agnieszka Wrobel
- Department of Biosciences, University of Oslo, 0316 Oslo, Norway
| | - Claudio Ottoni
- Department of Biosciences, University of Oslo, 0316 Oslo, Norway; Centre for Ecological and Evolutionary Synthesis, University of Oslo, 0316, Norway
| | - Jack C Leo
- Department of Biosciences, University of Oslo, 0316 Oslo, Norway
| | - Snorre Gulla
- Norwegian Veterinary Institute, 0454 Oslo, Norway
| | - Dirk Linke
- Department of Biosciences, University of Oslo, 0316 Oslo, Norway.
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43
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Guérin J, Bigot S, Schneider R, Buchanan SK, Jacob-Dubuisson F. Two-Partner Secretion: Combining Efficiency and Simplicity in the Secretion of Large Proteins for Bacteria-Host and Bacteria-Bacteria Interactions. Front Cell Infect Microbiol 2017; 7:148. [PMID: 28536673 PMCID: PMC5422565 DOI: 10.3389/fcimb.2017.00148] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 04/10/2017] [Indexed: 12/31/2022] Open
Abstract
Initially identified in pathogenic Gram-negative bacteria, the two-partner secretion (TPS) pathway, also known as Type Vb secretion, mediates the translocation across the outer membrane of large effector proteins involved in interactions between these pathogens and their hosts. More recently, distinct TPS systems have been shown to secrete toxic effector domains that participate in inter-bacterial competition or cooperation. The effects of these systems are based on kin vs. non-kin molecular recognition mediated by specific immunity proteins. With these new toxin-antitoxin systems, the range of TPS effector functions has thus been extended from cytolysis, adhesion, and iron acquisition, to genome maintenance, inter-bacterial killing and inter-bacterial signaling. Basically, a TPS system is made up of two proteins, the secreted TpsA effector protein and its TpsB partner transporter, with possible additional factors such as immunity proteins for protection against cognate toxic effectors. Structural studies have indicated that TpsA proteins mainly form elongated β helices that may be followed by specific functional domains. TpsB proteins belong to the Omp85 superfamily. Open questions remain on the mechanism of protein secretion in the absence of ATP or an electrochemical gradient across the outer membrane. The remarkable dynamics of the TpsB transporters and the progressive folding of their TpsA partners at the bacterial surface in the course of translocation are thought to be key elements driving the secretion process.
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Affiliation(s)
- Jeremy Guérin
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of HealthBethesda, MD, USA
| | - Sarah Bigot
- Molecular Microbiology and Structural Biochemistry, Centre National de La Recherche Scientifique UMR 5086-Université Lyon 1, Institute of Biology and Chemistry of ProteinsLyon, France
| | - Robert Schneider
- NMR and Molecular Interactions, Université de Lille, Centre National de La Recherche Scientifique, UMR 8576-Unité de Glycobiologie Structurale et FonctionnelleLille, France
| | - Susan K Buchanan
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of HealthBethesda, MD, USA
| | - Françoise Jacob-Dubuisson
- Université de Lille, Centre National de La Recherche Scientifique, Institut National de La Santé et de La Recherche Médicale, CHU Lille, Institut Pasteur de Lille, U1019-UMR 8204-Centre d'Infection et d'Immunité de LilleLille, France
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44
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Sadana P, Mönnich M, Unverzagt C, Scrima A. Structure of the Y. pseudotuberculosis adhesin InvasinE. Protein Sci 2017; 26:1182-1195. [PMID: 28370712 DOI: 10.1002/pro.3171] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 03/24/2017] [Indexed: 12/20/2022]
Abstract
Enteropathogenic Yersinia expresses several invasins that are fundamental virulence factors required for adherence and colonization of tissues in the host. Within the invasin-family of Yersinia adhesins, to date only Invasin has been extensively studied at both structural and functional levels. In this work, we structurally characterize the recently identified inverse autotransporter InvasinE from Yersinia pseudotuberculosis (formerly InvasinD from Yersinia pseudotuberculosis strain IP31758) that belongs to the invasin-family of proteins. The sequence of the C-terminal adhesion domain of InvasinE differs significantly from that of other members of the Yersinia invasin-family and its detailed cellular and molecular function remains elusive. In this work, we present the 1.7 Å crystal structure of the adhesion domain of InvasinE along with two Immunoglobulin-like domains. The structure reveals a rod shaped architecture, confirmed by small angle X-ray scattering in solution. The adhesion domain exhibits strong structural similarities to the C-type lectin-like domain of Yersinia pseudotuberculosis Invasin and enteropathogenic/enterohemorrhagic E. coli Intimin. However, despite the overall structural similarity, the C-type lectin-like domain in InvasinE lacks motifs required for Ca2+ /carbohydrate binding as well as sequence or structural features critical for Tir binding in Intimin and β1 -integrin binding in Invasin, suggesting that InvasinE targets a distinct, yet unidentified molecule on the host-cell surface. Although the biological role and target molecule of InvasinE remain to be elucidated, our structural data provide novel insights into the architecture of invasin-family proteins and a platform for further studies towards unraveling the function of InvasinE in the context of infection and host colonization.
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Affiliation(s)
- Pooja Sadana
- Structural Biology of Autophagy Group, Department of Structure and Function of Proteins, Helmholtz Centre for Infection Research, Braunschweig, 38124, Germany
| | - Manuel Mönnich
- Bioorganic Chemistry, Gebäude NW1, Universität Bayreuth, Bayreuth, 95440, Germany
| | - Carlo Unverzagt
- Bioorganic Chemistry, Gebäude NW1, Universität Bayreuth, Bayreuth, 95440, Germany
| | - Andrea Scrima
- Structural Biology of Autophagy Group, Department of Structure and Function of Proteins, Helmholtz Centre for Infection Research, Braunschweig, 38124, Germany
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45
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Dunne KA, Chaudhuri RR, Rossiter AE, Beriotto I, Browning DF, Squire D, Cunningham AF, Cole JA, Loman N, Henderson IR. Sequencing a piece of history: complete genome sequence of the original Escherichia coli strain. Microb Genom 2017; 3:mgen000106. [PMID: 28663823 PMCID: PMC5382810 DOI: 10.1099/mgen.0.000106] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 01/24/2017] [Indexed: 12/30/2022] Open
Abstract
In 1885, Theodor Escherich first described the Bacillus coli commune, which was subsequently renamed Escherichia coli. We report the complete genome sequence of this original strain (NCTC 86). The 5 144 392 bp circular chromosome encodes the genes for 4805 proteins, which include antigens, virulence factors, antimicrobial-resistance factors and secretion systems, of a commensal organism from the pre-antibiotic era. It is located in the E. coli A subgroup and is closely related to E. coli K-12 MG1655. E. coli strain NCTC 86 and the non-pathogenic K-12, C, B and HS strains share a common backbone that is largely co-linear. The exception is a large 2 803 932 bp inversion that spans the replication terminus from gmhB to clpB. Comparison with E. coli K-12 reveals 41 regions of difference (577 351 bp) distributed across the chromosome. For example, and contrary to current dogma, E. coli NCTC 86 includes a nine gene sil locus that encodes a silver-resistance efflux pump acquired before the current widespread use of silver nanoparticles as an antibacterial agent, possibly resulting from the widespread use of silver utensils and currency in Germany in the 1800s. In summary, phylogenetic comparisons with other E. coli strains confirmed that the original strain isolated by Escherich is most closely related to the non-pathogenic commensal strains. It is more distant from the root than the pathogenic organisms E. coli 042 and O157 : H7; therefore, it is not an ancestral state for the species.
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Affiliation(s)
- Karl A Dunne
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, UK
| | - Roy R Chaudhuri
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, UK
| | - Amanda E Rossiter
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, UK
| | - Irene Beriotto
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, UK
| | - Douglas F Browning
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, UK
| | - Derrick Squire
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, UK
| | - Adam F Cunningham
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, UK
| | - Jeffrey A Cole
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, UK
| | - Nicholas Loman
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, UK
| | - Ian R Henderson
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, UK
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46
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Comparative genomics of Vibrio campbellii strains and core species of the Vibrio Harveyi clade. Sci Rep 2017; 7:41394. [PMID: 28145490 PMCID: PMC5286417 DOI: 10.1038/srep41394] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 12/19/2016] [Indexed: 01/09/2023] Open
Abstract
The core of the Vibrio Harveyi clade contains V. harveyi, V. campbellii, V. owensii, V. jasicida, and V. rotiferianus. They are well recognized aquatic animal pathogens, but misclassification has been common due to similarities in their rDNA sequences and phenotypes. To better understand their evolutionary relationships and functional features, we sequenced a shrimp pathogen strain V. harveyi 1114GL, reclassified it as V. campbellii and compared this and 47 other sequenced Vibrio genomes in the Harveryi clade. A phylogeny based on 1,775 genes revealed that both V. owensii and V. jasicida were closer to V. campbellii than to V. harveyi and that V. campbellii strains can be divided into two distinct groups. Species-specific genes such as intimin and iron acquisition genes were identified in V. campbellii. In particular, the 1114GL strain contains two bacterial immunoglobulin-like genes for cell adhesion with 22 Big_2 domains that have been extensively reshuffled and are by far the most expanded among all species surveyed in this study. The 1114GL strain differed from ATCC BAA-1116 by ~9% at the synonymous sites, indicating high diversity within V. campbellii. Our study revealed the characteristics of V. campbellii in the Harveyi clade and the genetic basis for their wide-spread pathogenicity.
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47
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Corbishley A, Connelley TK, Wolfson EB, Ballingall K, Beckett AE, Gally DL, McNeilly TN. Identification of epitopes recognised by mucosal CD4(+) T-cell populations from cattle experimentally colonised with Escherichia coli O157:H7. Vet Res 2016; 47:90. [PMID: 27590451 PMCID: PMC5010706 DOI: 10.1186/s13567-016-0374-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 08/02/2016] [Indexed: 12/24/2022] Open
Abstract
Vaccines targeting enterohaemorrhagic Escherichia coli (EHEC) O157:H7 shedding in cattle are only partially protective. The correlates of protection of these vaccines are unknown, but it is probable that they reduce bacterial adherence at the mucosal surface via the induction of blocking antibodies. Recent studies have indicated a role for cellular immunity in cattle during colonisation, providing an impetus to understand the bacterial epitopes recognised during this response. This study mapped the epitopes of 16 EHEC O157:H7 proteins recognised by rectal lymph node CD4(+) T-cells from calves colonised with Shiga toxin producing EHEC O157:H7 strains. 20 CD4(+) T-cell epitopes specific to E. coli from 7 of the proteins were identified. The highly conserved N-terminal region of Intimin, including the signal peptide, was consistently recognised by mucosal CD4(+) T-cell populations from multiple animals of different major histocompatibility complex class II haplotypes. These T-cell epitopes are missing from many Intimin constructs used in published vaccine trials, but are relatively conserved across a range of EHEC serotypes, offering the potential to develop cross protective vaccines. Antibodies recognising H7 flagellin have been consistently identified in colonised calves; however CD4(+) T-cell epitopes from H7 flagellin were not identified in this study, suggesting that H7 flagellin may act as a T-cell independent antigen. This is the first time that the epitopes recognised by CD4(+) T-cells following colonisation with an attaching and effacing pathogen have been characterised in any species. The findings have implications for the design of antigens used in the next generation of EHEC O157:H7 vaccines.
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Affiliation(s)
- Alexander Corbishley
- Farm Animal Practice, Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK.,Division of Immunity and Infection, The Roslin Institute, The University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK
| | - Timothy K Connelley
- Division of Immunity and Infection, The Roslin Institute, The University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK
| | - Eliza B Wolfson
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, UK
| | - Keith Ballingall
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, EH26 0PZ, UK
| | - Amy E Beckett
- Division of Immunity and Infection, The Roslin Institute, The University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK.,Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, EH26 0PZ, UK
| | - David L Gally
- Division of Immunity and Infection, The Roslin Institute, The University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK
| | - Tom N McNeilly
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, EH26 0PZ, UK.
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48
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Leo JC, Oberhettinger P, Yoshimoto S, Udatha DBRKG, Morth JP, Schütz M, Hori K, Linke D. Secretion of the Intimin Passenger Domain Is Driven by Protein Folding. J Biol Chem 2016; 291:20096-112. [PMID: 27466361 DOI: 10.1074/jbc.m116.731497] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Indexed: 11/06/2022] Open
Abstract
Intimin is an essential adhesin of attaching and effacing organisms such as entropathogenic Escherichia coli It is also the prototype of type Ve secretion or inverse autotransport, where the extracellular C-terminal region or passenger is exported with the help of an N-terminal transmembrane β-barrel domain. We recently reported a stalled secretion intermediate of intimin, where the passenger is located in the periplasm but the β-barrel is already inserted into the membrane. Stalling of this mutant is due to the insertion of an epitope tag at the very N terminus of the passenger. Here, we examined how this insertion disrupts autotransport and found that it causes misfolding of the N-terminal immunoglobulin (Ig)-like domain D00. We could also stall the secretion by making an internal deletion in D00, and introducing the epitope tag into the second Ig-like domain, D0, also resulted in reduced passenger secretion. In contrast to many classical autotransporters, where a proximal folding core in the passenger is required for secretion, the D00 domain is dispensable, as the passenger of an intimin mutant lacking D00 entirely is efficiently exported. Furthermore, the D00 domain is slightly less stable than the D0 and D1 domains, unfolding at ∼200 piconewtons (pN) compared with ∼250 pN for D0 and D1 domains as measured by atomic force microscopy. Our results support a model where the secretion of the passenger is driven by sequential folding of the extracellular Ig-like domains, leading to vectorial transport of the passenger domain across the outer membrane in an N to C direction.
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Affiliation(s)
- Jack C Leo
- From the Evolution and Genetics, Department of Biosciences, University of Oslo, 0316 Oslo, Norway
| | - Philipp Oberhettinger
- Interfaculty Institute for Microbiology and Infection Medicine, University Clinics Tübingen, 72076 Tübingen, Germany
| | - Shogo Yoshimoto
- Department of Biotechnology, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan, and
| | - D B R K Gupta Udatha
- From the Evolution and Genetics, Department of Biosciences, University of Oslo, 0316 Oslo, Norway
| | | | - Monika Schütz
- Interfaculty Institute for Microbiology and Infection Medicine, University Clinics Tübingen, 72076 Tübingen, Germany
| | - Katsutoshi Hori
- Department of Biotechnology, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan, and
| | - Dirk Linke
- From the Evolution and Genetics, Department of Biosciences, University of Oslo, 0316 Oslo, Norway,
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49
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Monteiro R, Ageorges V, Rojas-Lopez M, Schmidt H, Weiss A, Bertin Y, Forano E, Jubelin G, Henderson IR, Livrelli V, Gobert AP, Rosini R, Soriani M, Desvaux M. A secretome view of colonisation factors in Shiga toxin-encodingEscherichia coli(STEC): from enterohaemorrhagicE. coli(EHEC) to related enteropathotypes. FEMS Microbiol Lett 2016; 363:fnw179. [DOI: 10.1093/femsle/fnw179] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/18/2016] [Indexed: 12/25/2022] Open
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50
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Heinz E, Stubenrauch CJ, Grinter R, Croft NP, Purcell AW, Strugnell RA, Dougan G, Lithgow T. Conserved Features in the Structure, Mechanism, and Biogenesis of the Inverse Autotransporter Protein Family. Genome Biol Evol 2016; 8:1690-705. [PMID: 27190006 PMCID: PMC4943183 DOI: 10.1093/gbe/evw112] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The bacterial cell surface proteins intimin and invasin are virulence factors that share a common domain structure and bind selectively to host cell receptors in the course of bacterial pathogenesis. The β-barrel domains of intimin and invasin show significant sequence and structural similarities. Conversely, a variety of proteins with sometimes limited sequence similarity have also been annotated as “intimin-like” and “invasin” in genome datasets, while other recent work on apparently unrelated virulence-associated proteins ultimately revealed similarities to intimin and invasin. Here we characterize the sequence and structural relationships across this complex protein family. Surprisingly, intimins and invasins represent a very small minority of the sequence diversity in what has been previously the “intimin/invasin protein family”. Analysis of the assembly pathway for expression of the classic intimin, EaeA, and a characteristic example of the most prevalent members of the group, FdeC, revealed a dependence on the translocation and assembly module as a common feature for both these proteins. While the majority of the sequences in the grouping are most similar to FdeC, a further and widespread group is two-partner secretion systems that use the β-barrel domain as the delivery device for secretion of a variety of virulence factors. This comprehensive analysis supports the adoption of the “inverse autotransporter protein family” as the most accurate nomenclature for the family and, in turn, has important consequences for our overall understanding of the Type V secretion systems of bacterial pathogens.
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Affiliation(s)
- Eva Heinz
- Department of Microbiology, Infection & Immunity Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | - Christopher J Stubenrauch
- Department of Microbiology, Infection & Immunity Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
| | - Rhys Grinter
- Department of Microbiology, Infection & Immunity Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia Institute of Microbiology and Infection, School of Immunity and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Nathan P Croft
- Department of Biochemistry and Molecular Biology, Infection & Immunity Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
| | - Anthony W Purcell
- Department of Biochemistry and Molecular Biology, Infection & Immunity Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
| | - Richard A Strugnell
- Department of Microbiology & Immunology, University of Melbourne, Parkville, Australia
| | - Gordon Dougan
- Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | - Trevor Lithgow
- Department of Microbiology, Infection & Immunity Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
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