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Bettin EB, Grassmann AA, Dellagostin OA, Gogarten JP, Caimano MJ. Leptospira interrogans encodes a canonical BamA and three novel noNterm Omp85 outer membrane protein paralogs. Sci Rep 2024; 14:19958. [PMID: 39198480 PMCID: PMC11358297 DOI: 10.1038/s41598-024-67772-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2024] [Accepted: 07/15/2024] [Indexed: 09/01/2024] Open
Abstract
The Omp85 family of outer membrane proteins are ubiquitously distributed among diderm bacteria and play essential roles in outer membrane (OM) biogenesis. The majority of Omp85 orthologs are bipartite and consist of a conserved OM-embedded 16-stranded beta-barrel and variable periplasmic functional domains. Here, we demonstrate that Leptospira interrogans encodes four distinct Omp85 proteins. The presumptive leptospiral BamA, LIC11623, contains a noncanonical POTRA4 periplasmic domain that is conserved across Leptospiraceae. The remaining three leptospiral Omp85 proteins, LIC12252, LIC12254 and LIC12258, contain conserved beta-barrels but lack periplasmic domains. Two of the three 'noNterm' Omp85-like proteins were upregulated by leptospires in urine from infected mice compared to in vitro and/or following cultivation within rat peritoneal cavities. Mice infected with a L. interrogans lic11254 transposon mutant shed tenfold fewer leptospires in their urine compared to mice infected with the wild-type parent. Analyses of pathogenic and saprophytic Leptospira spp. identified five groups of noNterm Omp85 paralogs, including one pathogen- and two saprophyte-specific groups. Expanding our analysis beyond Leptospira spp., we identified additional noNterm Omp85 orthologs in bacteria isolated from diverse environments, suggesting a potential role for these previously unrecognized noNterm Omp85 proteins in physiological adaptation to harsh conditions.
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Affiliation(s)
- Everton B Bettin
- Department of Medicine, University of Connecticut Health, 263 Farmington Avenue, Farmington, CT, 06030-3715, USA
| | - André A Grassmann
- Department of Medicine, University of Connecticut Health, 263 Farmington Avenue, Farmington, CT, 06030-3715, USA
| | - Odir A Dellagostin
- Biotechnology Unit, Technological Development Center, Federal University of Pelotas, Pelotas, RS, Brazil
| | - Johann Peter Gogarten
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA
- Institute for Systems Genomics, University of Connecticut, Storrs, CT, USA
| | - Melissa J Caimano
- Department of Medicine, University of Connecticut Health, 263 Farmington Avenue, Farmington, CT, 06030-3715, USA.
- Department of Pediatrics, University of Connecticut Health, Farmington, CT, USA.
- Department of Molecular Biology and Biophysics, University of Connecticut Health, Farmington, CT, USA.
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2
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Surdel MC, Coburn J. Leptospiral adhesins: from identification to future perspectives. Front Microbiol 2024; 15:1458655. [PMID: 39206373 PMCID: PMC11350617 DOI: 10.3389/fmicb.2024.1458655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2024] [Accepted: 08/01/2024] [Indexed: 09/04/2024] Open
Abstract
Leptospirosis is a significant zoonosis worldwide, with disease severity ranging from a mild non-specific illness to multi-organ dysfunction and hemorrhage. The disease is caused by pathogenic bacteria of the genus Leptospira, which are classified into pathogenic and saprophytic clades. Bacterial binding to host molecules and cells, coordinated by adhesin proteins, is an important step in pathogenesis. While many leptospiral adhesins have been identified, the vast majority have not been characterized in vivo. Herein, we present an overview of the current methodologies and successes in identifying adhesins in Leptospira, including known biological roles in vivo. We will also identify and discuss potential areas for future research.
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Affiliation(s)
- Matthew C. Surdel
- Division of Infectious Diseases, Department of Medicine, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Jenifer Coburn
- Division of Infectious Diseases, Department of Medicine, Medical College of Wisconsin, Milwaukee, WI, United States
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI, United States
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3
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Afonso AC, Botting J, Gomes IB, Saavedra MJ, Simões LC, Liu J, Simões M. Elucidating bacterial coaggregation through a physicochemical and imaging surface characterization. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 948:174872. [PMID: 39032752 DOI: 10.1016/j.scitotenv.2024.174872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2024] [Revised: 07/10/2024] [Accepted: 07/16/2024] [Indexed: 07/23/2024]
Abstract
Bacterial coaggregation is a highly specific type of cell-cell interaction, well-documented among oral bacteria, and involves specific characteristics of the cell surface of the coaggregating strains. However, the understanding of the mechanisms promoting coaggregation in aquatic systems remains limited. This gap is critical to address, given the broad implications of coaggregation for multispecies biofilm formation, water quality, the performance of engineered systems, and diverse biotechnological applications. Therefore, this study aims to comprehensively characterize the cell surface of the coaggregating strain Delftia acidovorans 005P, isolated from drinking water, alongside a non-coaggregating strain, D. acidovorans 009P. By analyzing two strains of the same species, we aim to identify the factors contributing to the coaggregation ability of strain 005P. To achieve this, we employed a combination of physicochemical characterization, Fourier-transform infrared spectroscopy (FTIR), and advancing imaging techniques [transmission electron microscopy and cryo-electron tomography (cryo-ET)]. The coaggregating strain (005P) exhibited higher surface hydrophobicity, negative surface charge, and cell surface and co-adhesion energies than the non-coaggregating strain (009P). The chemical characterization of bacterial surfaces through FTIR revealed subtle differences, particularly in spectral regions linked to carbohydrates and phosphodiesters/amide III of proteins (860-930 cm-1 and 1212-1240 cm-1, respectively). Cryo-ET highlighted significant differences in pili structures between the strains, such as variations in length, frequency, and arrangement. The pili in the 005P strain, identified as pili-like adhesins, serve as key mediators of coaggregation. By integrating physicochemical analyses and high-resolution imaging techniques, this study conclusively links the coaggregation ability of D. acidovorans 005P to its unique pili characteristics, emphasizing their crucial role in microbial coaggregation in aquatic environments.
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Affiliation(s)
- Ana C Afonso
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr Roberto Frias, 4200-465 Porto, Portugal; ALiCE - Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr Roberto Frias, 4200-465 Porto, Portugal; CITAB, Department of Veterinary Sciences, University of Trás-os-Montes e Alto Douro, 5000-801 Vila Real, Portugal; CEB-LABBELS, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Jack Botting
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT 06536, United States; New Haven Microbial Sciences Institute, Yale University, West Haven, CT 06516, United States
| | - Inês B Gomes
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr Roberto Frias, 4200-465 Porto, Portugal; ALiCE - Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr Roberto Frias, 4200-465 Porto, Portugal
| | - Maria J Saavedra
- CITAB, Department of Veterinary Sciences, University of Trás-os-Montes e Alto Douro, 5000-801 Vila Real, Portugal
| | - Lúcia C Simões
- CEB-LABBELS, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Jun Liu
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT 06536, United States; New Haven Microbial Sciences Institute, Yale University, West Haven, CT 06516, United States
| | - Manuel Simões
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr Roberto Frias, 4200-465 Porto, Portugal; ALiCE - Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr Roberto Frias, 4200-465 Porto, Portugal.
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4
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Li X, Hou Y, Zou H, Wang Y, Xu Y, Wang L, Wang B, Yan M, Leng X. Unraveling the efficacy of verbascoside in thwarting MRSA pathogenicity by targeting sortase A. Appl Microbiol Biotechnol 2024; 108:360. [PMID: 38836914 PMCID: PMC11153306 DOI: 10.1007/s00253-024-13202-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 05/10/2024] [Accepted: 05/23/2024] [Indexed: 06/06/2024]
Abstract
In the fight against hospital-acquired infections, the challenge posed by methicillin-resistant Staphylococcus aureus (MRSA) necessitates the development of novel treatment methods. This study focused on undermining the virulence of S. aureus, especially by targeting surface proteins crucial for bacterial adherence and evasion of the immune system. A primary aspect of our approach involves inhibiting sortase A (SrtA), a vital enzyme for attaching microbial surface components recognizing adhesive matrix molecules (MSCRAMMs) to the bacterial cell wall, thereby reducing the pathogenicity of S. aureus. Verbascoside, a phenylethanoid glycoside, was found to be an effective SrtA inhibitor in our research. Advanced fluorescence quenching and molecular docking studies revealed a specific interaction between verbascoside and SrtA, pinpointing the critical active sites involved in this interaction. This molecular interaction significantly impedes the SrtA-mediated attachment of MSCRAMMs, resulting in a substantial reduction in bacterial adhesion, invasion, and biofilm formation. The effectiveness of verbascoside has also been demonstrated in vivo, as shown by its considerable protective effects on pneumonia and Galleria mellonella (wax moth) infection models. These findings underscore the potential of verbascoside as a promising component in new antivirulence therapies for S. aureus infections. By targeting crucial virulence factors such as SrtA, agents such as verbascoside constitute a strategic and potent approach for tackling antibiotic resistance worldwide. KEY POINTS: • Verbascoside inhibits SrtA, reducing S. aureus adhesion and biofilm formation. • In vivo studies demonstrated the efficacy of verbascoside against S. aureus infections. • Targeting virulence factors such as SrtA offers new avenues against antibiotic resistance.
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Affiliation(s)
- Xingchen Li
- Changchun University of Chinese Medicine, Changchun, China
| | - Yingying Hou
- The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Haoyan Zou
- Changchun University of Chinese Medicine, Changchun, China
| | - Yueying Wang
- Changchun University of Chinese Medicine, Changchun, China
| | - Yueshan Xu
- Changchun University of Chinese Medicine, Changchun, China
| | - Li Wang
- Changchun University of Chinese Medicine, Changchun, China
| | - Bingmei Wang
- Changchun University of Chinese Medicine, Changchun, China
| | - Ming Yan
- Changchun University of Chinese Medicine, Changchun, China.
| | - Xiangyang Leng
- Changchun University of Chinese Medicine, Changchun, China.
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5
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Sonnert ND, Rosen CE, Ghazi AR, Franzosa EA, Duncan-Lowey B, González-Hernández JA, Huck JD, Yang Y, Dai Y, Rice TA, Nguyen MT, Song D, Cao Y, Martin AL, Bielecka AA, Fischer S, Guan C, Oh J, Huttenhower C, Ring AM, Palm NW. A host-microbiota interactome reveals extensive transkingdom connectivity. Nature 2024; 628:171-179. [PMID: 38509360 DOI: 10.1038/s41586-024-07162-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Accepted: 02/05/2024] [Indexed: 03/22/2024]
Abstract
The myriad microorganisms that live in close association with humans have diverse effects on physiology, yet the molecular bases for these impacts remain mostly unknown1-3. Classical pathogens often invade host tissues and modulate immune responses through interactions with human extracellular and secreted proteins (the 'exoproteome'). Commensal microorganisms may also facilitate niche colonization and shape host biology by engaging host exoproteins; however, direct exoproteome-microbiota interactions remain largely unexplored. Here we developed and validated a novel technology, BASEHIT, that enables proteome-scale assessment of human exoproteome-microbiome interactions. Using BASEHIT, we interrogated more than 1.7 million potential interactions between 519 human-associated bacterial strains from diverse phylogenies and tissues of origin and 3,324 human exoproteins. The resulting interactome revealed an extensive network of transkingdom connectivity consisting of thousands of previously undescribed host-microorganism interactions involving 383 strains and 651 host proteins. Specific binding patterns within this network implied underlying biological logic; for example, conspecific strains exhibited shared exoprotein-binding patterns, and individual tissue isolates uniquely bound tissue-specific exoproteins. Furthermore, we observed dozens of unique and often strain-specific interactions with potential roles in niche colonization, tissue remodelling and immunomodulation, and found that strains with differing host interaction profiles had divergent interactions with host cells in vitro and effects on the host immune system in vivo. Overall, these studies expose a previously unexplored landscape of molecular-level host-microbiota interactions that may underlie causal effects of indigenous microorganisms on human health and disease.
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Affiliation(s)
- Nicole D Sonnert
- Department of Immunobiology, Yale School of Medicine, New Haven, CT, USA
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT, USA
| | - Connor E Rosen
- Department of Immunobiology, Yale School of Medicine, New Haven, CT, USA
| | - Andrew R Ghazi
- Department of Biostatistics, Harvard T. H. Chan School of Public Health, Boston, MA, USA
- Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Eric A Franzosa
- Department of Biostatistics, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | | | | | - John D Huck
- Department of Immunobiology, Yale School of Medicine, New Haven, CT, USA
| | - Yi Yang
- Department of Immunobiology, Yale School of Medicine, New Haven, CT, USA
| | - Yile Dai
- Department of Immunobiology, Yale School of Medicine, New Haven, CT, USA
| | - Tyler A Rice
- Department of Immunobiology, Yale School of Medicine, New Haven, CT, USA
| | - Mytien T Nguyen
- Department of Immunobiology, Yale School of Medicine, New Haven, CT, USA
| | - Deguang Song
- Department of Immunobiology, Yale School of Medicine, New Haven, CT, USA
| | - Yiyun Cao
- Department of Immunobiology, Yale School of Medicine, New Haven, CT, USA
| | - Anjelica L Martin
- Department of Immunobiology, Yale School of Medicine, New Haven, CT, USA
| | - Agata A Bielecka
- Department of Immunobiology, Yale School of Medicine, New Haven, CT, USA
| | - Suzanne Fischer
- Department of Immunobiology, Yale School of Medicine, New Haven, CT, USA
| | - Changhui Guan
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, USA
| | - Julia Oh
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, USA
| | - Curtis Huttenhower
- Department of Biostatistics, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | - Aaron M Ring
- Department of Immunobiology, Yale School of Medicine, New Haven, CT, USA.
- Department of Pharmacology, Yale School of Medicine, New Haven, CT, USA.
| | - Noah W Palm
- Department of Immunobiology, Yale School of Medicine, New Haven, CT, USA.
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6
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Baykov IK, Tikunov AY, Babkin IV, Fedorets VA, Zhirakovskaia EV, Tikunova NV. Tentaclins-A Novel Family of Phage Receptor-Binding Proteins That Can Be Hypermutated by DGR Systems. Int J Mol Sci 2023; 24:17324. [PMID: 38139153 PMCID: PMC10743442 DOI: 10.3390/ijms242417324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 11/29/2023] [Accepted: 12/05/2023] [Indexed: 12/24/2023] Open
Abstract
Diversity-generating retroelements (DGRs) are prokaryotic systems providing rapid modification and adaptation of target proteins. In phages, the main targets of DGRs are receptor-binding proteins that are usually parts of tail structures and the variability of such host-recognizing structures enables phage adaptation to changes on the bacterial host surface. Sometimes, more than one target gene containing a hypermutated variable repeat (VR) can be found in phage DGRs. The role of mutagenesis of two functionally different genes is unclear. In this study, several phage genomes that contain DGRs with two target genes were found in the gut virome of healthy volunteers. Bioinformatics analysis of these genes indicated that they encode proteins with different topology; however, both proteins contain the C-type lectin (C-lec) domain with a hypermutated beta-hairpin on its surface. One of the target proteins belongs to a new family of proteins with a specific topology: N-terminal C-lec domain followed by one or more immunoglobulin domains. Proteins from the new family were named tentaclins after TENTACLe + proteIN. The genes encoding such proteins were found in the genomes of prophages and phages from the gut metagenomes. We hypothesized that tentaclins are involved in binding either to bacterial receptors or intestinal/immune cells.
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Affiliation(s)
- Ivan K. Baykov
- Federal State Public Scientific Institution «Institute of Chemical Biology and Fundamental Medicine», Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia
| | | | | | | | | | - Nina V. Tikunova
- Federal State Public Scientific Institution «Institute of Chemical Biology and Fundamental Medicine», Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia
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7
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Guo Z, Ma Y, Jia Z, Wang L, Lu X, Chen Y, Wang Y, Hao H, Yu S, Wang Z. Crosstalk between integrin/FAK and Crk/Vps25 governs invasion of bovine mammary epithelial cells by S. agalactiae. iScience 2023; 26:107884. [PMID: 37766995 PMCID: PMC10520442 DOI: 10.1016/j.isci.2023.107884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 07/26/2023] [Accepted: 09/07/2023] [Indexed: 09/29/2023] Open
Abstract
Streptococcus agalactiae (S. agalactiae) is a contagious obligate parasite of the udder in dairy cows. Here, we examined S. agalactiae-host interactions in bovine mammary epithelial cells (BMECs) in vitro. We found that S. agalactiae infected BMECs through laminin β2 and integrin. Crk, Vps25, and RhoA were differentially expressed in S. agalactiae-infected cells. S. agalactiae infection activated FAK and Crk. FAK deficiency decreased the number of intracellular S. agalactiae and Crk activation. Knockdown of Crk or Vps25 increased the level of intracellular S. agalactiae, whereas its overexpression had the opposite effect. RhoA expression and actin cytoskeleton were altered in S. agalactiae-infected BMECs. Crk and Vps25 interact in cells, and invaded S. agalactiae also activates Crk, allowing it to cooperate with Vps25 to defend against intracellular infection by S. agalactiae. This study provides insights into the mechanism by which intracellular infection by S. agalactiae is regulated in BMECs.
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Affiliation(s)
- Zhixin Guo
- State Key Laboratory of Reproductive Regulation & Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot 010021, China
- School of Fisheries and Life Science, Dalian Ocean University, Dalian 116023, China
| | - Yuze Ma
- State Key Laboratory of Reproductive Regulation & Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot 010021, China
| | - Zhibo Jia
- State Key Laboratory of Reproductive Regulation & Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot 010021, China
| | - Liping Wang
- State Key Laboratory of Reproductive Regulation & Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot 010021, China
| | - Xinyue Lu
- State Key Laboratory of Reproductive Regulation & Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot 010021, China
| | - Yuhao Chen
- State Key Laboratory of Reproductive Regulation & Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot 010021, China
- School of Life Sciences, Jining Normal University, Jining 012000, China
| | - Yanfeng Wang
- State Key Laboratory of Reproductive Regulation & Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot 010021, China
| | - Huifang Hao
- State Key Laboratory of Reproductive Regulation & Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot 010021, China
| | - Shuixing Yu
- State Key Laboratory of Reproductive Regulation & Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot 010021, China
| | - Zhigang Wang
- State Key Laboratory of Reproductive Regulation & Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot 010021, China
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Kumar P, Vyas P, Faisal SM, Chang YF, Akif M. Crystal structure of a variable region segment of Leptospira host-interacting outer surface protein, LigA, reveals the orientation of Ig-like domains. Int J Biol Macromol 2023:125445. [PMID: 37336372 DOI: 10.1016/j.ijbiomac.2023.125445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 06/13/2023] [Accepted: 06/14/2023] [Indexed: 06/21/2023]
Abstract
Leptospiral immunoglobulin-like (Lig) protein family is a surface-exposed protein from the pathogenic Leptospira. The Lig protein family has been identified as an essential virulence factor of L. interrogan. One of the family members, LigA, contains 13 homologous tandem repeats of bacterial Ig-like (Big) domains in its extracellular portion. It is crucial in binding with the host's Extracellular matrices (ECM) and complement factors. However, its vital role in the invasion and evasion of pathogenic Leptospira, structural details, and domain organization of the extracellular portion of this protein are not explored thoroughly. Here, we described the first high-resolution crystal structure of a variable region segment (LigA8-9) of LigA at 1.87 Å resolution. The structure showed some remarkably distinctive aspects compared with the most closely related Immunoglobulin superfamily (IgSF) members. The structure illustrated the relative orientation of two domains and highlighted the role of the linker region in the domain orientation. We also observed an apparent electron density of Ca2+ ions coordinated with a proper interacting geometry within the protein. Molecular dynamic simulations demonstrated the involvement of a linker salt bridge in providing rigidity between the two domains. Our study proposes an overall arrangement of Ig-like domains in the LigA protein. The structural understanding of the extracellular portion of LigA and its interaction with the ECM provides insight into developing new therapeutics directed toward leptospirosis.
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Affiliation(s)
- Pankaj Kumar
- Laboratory of Structural Biology, Department of Biochemistry, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad, India
| | - Pallavi Vyas
- Laboratory of Vaccine Immunology, National Institute of Animal Biotechnology, Gachibowli, Hyderabad, Telangana, India
| | - Syed M Faisal
- Laboratory of Vaccine Immunology, National Institute of Animal Biotechnology, Gachibowli, Hyderabad, Telangana, India
| | - Yung-Fu Chang
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA
| | - Mohd Akif
- Laboratory of Structural Biology, Department of Biochemistry, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad, India.
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9
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Ai W, Guo T, Lay KD, Ou K, Cai K, Ding Y, Liu J, Cao Y. Isolation of soybean-specific plant growth-promoting rhizobacteria using soybean agglutin and evaluation of their effects to improve soybean growth, yield, and soil nutritional status. Microbiol Res 2022; 261:127076. [PMID: 35636091 DOI: 10.1016/j.micres.2022.127076] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 05/06/2022] [Accepted: 05/16/2022] [Indexed: 11/26/2022]
Abstract
The basic requirements of plant growth-promoting rhizobacteria (PGPR) for field applications are that they have an affinity for the host plant and that they can colonize the rhizosphere. Here, a new technique was established using soybean agglutin (SBA) as a tool to isolate soybean-specific PGPR. Thirty-three PGPR strains with an affinity for soybean were obtained via the screening method with SBA. All 33 isolates were able to produce indole acetic acid and solubilize inorganic phosphate and potassium. Most isolates (93.94%) were able to solubilize organic phosphate and almost half (45.45%) were able to produce siderophores. More than 40% of the isolates exhibited all five plant growth-promoting traits. The isolate Enterobacter sp. strain DN9 was selected for further analyses of its rhizosphere colonization and soybean growth-promoting effects because of its excellent activity in phosphate and potassium solubilization. The luciferase luxAB gene was electrotransformed into DN9, and the labelled DN9 (DN9-L) was able to survive in the soybean rhizosphere and colonize new spaces as the soybean roots elongated. This strain positively affected root system development and soybean seedling growth. In pot and field experiments, the isolates DN9, DW1, and DW13 significantly increased the nutrient contents in rhizosphere soil and soybean leaves. On average, the seed number per plant and the seed weight per plant were increased by 20% and 24% respectively, in plants inoculated with these PGPR strains in the pot experiment. In a field experiment, compared with uninoculated plants, those inoculated with DW1 showed 46.78% higher pod number per plant and 5.23% higher seed oil content; those inoculated with DW13 showed 79.82% higher seed number per plant and 65.10% higher seed weight per plant; and those inoculated with DN9 showed 9.13% higher 100-seed weight. These results show that SBA can be used as a tool to isolate efficient PGPR to enhance soybean production.
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Affiliation(s)
- Wenfeng Ai
- School of Life Sciences, Anhui Agricultural University, Hefei 230036, Anhui, China
| | - Tingting Guo
- School of Life Sciences, Anhui Agricultural University, Hefei 230036, Anhui, China
| | - Khien Duc Lay
- School of Life Sciences, Anhui Agricultural University, Hefei 230036, Anhui, China
| | - Kangmiao Ou
- School of Life Sciences, Anhui Agricultural University, Hefei 230036, Anhui, China
| | - Ke Cai
- School of Life Sciences, Anhui Agricultural University, Hefei 230036, Anhui, China
| | - Yue Ding
- School of Life Sciences, Anhui Agricultural University, Hefei 230036, Anhui, China
| | - Jia Liu
- School of Life Sciences, Anhui Agricultural University, Hefei 230036, Anhui, China
| | - Yuanyuan Cao
- School of Life Sciences, Anhui Agricultural University, Hefei 230036, Anhui, China.
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10
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Surdel MC, Hahn BL, Anderson PN, Coburn J. Heterologous production of the adhesin LIC13411 from pathogenic Leptospira facilitates binding of non-pathogenic Leptospira in vitro and in vivo. Front Cell Infect Microbiol 2022; 12:917963. [PMID: 35937702 PMCID: PMC9354625 DOI: 10.3389/fcimb.2022.917963] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 06/27/2022] [Indexed: 01/19/2023] Open
Abstract
Leptospirosis is an important cause of morbidity and mortality worldwide. Disease severity ranges from asymptomatic colonization to widespread hemorrhage and multiorgan dysfunction. The causative agents, Leptospira spp., are zoonotic Gram-negative spirochetes. One important step in pathogenesis is binding of bacterial adhesins to host components. Previously our laboratory identified two L. interrogans candidate adhesins, LIC11574 and LIC13411, that bind to VE-cadherin in vitro. In the current study, we demonstrate the ability of two strains of pathogenic L. interrogans to disrupt the localization of VE-cadherin, a protein important to maintaining inter-endothelial junctions. Purified MBP-LIC11574 and MBP-LIC13411 bind human dermal microvascular endothelial cells in a pattern reminiscent of VE-cadherin, but do not disrupt VE-cadherin localization. Genes encoding the candidate adhesins from pathogenic Leptospira were cloned in an overexpression vector and introduced into non-pathogenic L. biflexa, creating gain-of-function strains producing LIC11574 or LIC13411. Protein production and localization to the outer membrane were confirmed by Triton X-114 fractionation. Although these strains do not disrupt VE-cadherin localization, production of LIC13411 increases binding of non-pathogenic Leptospira to human endothelial cells and specifically to VE-cadherin. In a short-term murine model of infection, LIC13411 production led to increased burdens of the non-pathogen in the lung, liver, kidney, and bladder. These data confirm the role of LIC13411 as an adhesin in Leptospira spp. and implicate it in dissemination to multiple organs. Importantly, anti-adhesin therapy has been shown to have many benefits over classical antibiotics. Taken together, this work provides novel insight into the pathogenesis of Leptospira spp. and identifies LIC13411 as a potential prophylactic and therapeutic target.
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Affiliation(s)
- Matthew C. Surdel
- Department of Medicine, Division of Infectious Diseases, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Beth L. Hahn
- Department of Medicine, Division of Infectious Diseases, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Phillip N. Anderson
- Department of Medicine, Division of Infectious Diseases, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Jenifer Coburn
- Department of Medicine, Division of Infectious Diseases, Medical College of Wisconsin, Milwaukee, WI, United States,Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI, United States,*Correspondence: Jenifer Coburn,
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11
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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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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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13
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Afonso AC, Gomes IB, Saavedra MJ, Giaouris E, Simões LC, Simões M. Bacterial coaggregation in aquatic systems. WATER RESEARCH 2021; 196:117037. [PMID: 33751976 DOI: 10.1016/j.watres.2021.117037] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 03/07/2021] [Accepted: 03/08/2021] [Indexed: 06/12/2023]
Abstract
The establishment of a sessile community is believed to occur in a sequence of steps where genetically distinct bacteria can become attached to partner cells via specific molecules, in a process known as coaggregation. The presence of bacteria with the ability to autoaggregate and coaggregate has been described for diverse aquatic systems, particularly freshwater, drinking water, wastewater, and marine water. In these aquatic systems, coaggregation already demonstrated a role in the development of complex multispecies sessile communities, including biofilms. While specific molecular aspects on coaggregation in aquatic systems remain to be understood, clear evidence exist on the impact of this mechanism in multispecies biofilm resilience and homeostasis. The identification of bridging bacteria among coaggregating consortia has potential to improve the performance of wastewater treatment plants and/or to contribute for the development of strategies to control undesirable biofilms. This study provides a comprehensive analysis on the occurrence and role of bacterial coaggregation in diverse aquatic systems. The potential of this mechanism in water-related biotechnology is further described, with particular emphasis on the role of bridging bacteria.
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Affiliation(s)
- Ana C Afonso
- LEPABE, Faculty of Engineering, Department of Chemical Engineering, University of Porto, Porto, Portugal
| | - Inês B Gomes
- LEPABE, Faculty of Engineering, Department of Chemical Engineering, University of Porto, Porto, Portugal
| | - Maria José Saavedra
- CITAB, Centre for the Research and Technology for Agro-Environment and Biological Sciences, University of Trás-os-Montes e Alto Douro, Vila Real, Portugal
| | - Efstathios Giaouris
- Department of Food Science and Nutrition, School of the Environment, University of the Aegean, Ierou Lochou 10 & Makrygianni, Myrina 81400, Lemnos, Greece
| | - Lúcia C Simões
- CEB, Centre of Biological Engineering, University of Minho, Campus de Gualtar, Braga, Portugal
| | - Manuel Simões
- LEPABE, Faculty of Engineering, Department of Chemical Engineering, University of Porto, Porto, Portugal.
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Ashokcoomar S, Loots DT, Beukes D, van Reenen M, Pillay B, Pillay M. M. tuberculosis curli pili (MTP) is associated with alterations in carbon, fatty acid and amino acid metabolism in a THP-1 macrophage infection model. Microb Pathog 2021; 154:104806. [PMID: 33610716 DOI: 10.1016/j.micpath.2021.104806] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 01/28/2021] [Accepted: 02/11/2021] [Indexed: 12/16/2022]
Abstract
The initial host-pathogen interaction is crucial for the establishment of infection. An improved understanding of the pathophysiology of Mycobacterium tuberculosis (M. tuberculosis) during macrophage infection can aid the development of intervention therapeutics against tuberculosis. M. tuberculosis curli pili (MTP) is a surface located adhesin, involved in the first point-of-contact between pathogen and host. This study aimed to better understand the role of MTP in modulating the intertwined metabolic pathways of M. tuberculosis and its THP-1 macrophage host. Metabolites were extracted from pelleted wet cell mass of THP-1 macrophages infected with M. tuberculosis wild-type V9124 (WT), Δmtp-deletion mutant and the mtp-complemented strains, respectively, via a whole metabolome extraction method using a 1:3:1 ratio of chloroform:methanol:water. Metabolites were detected by two-dimensional gas chromatography time-of-flight mass spectrometry. Significant metabolites were determined through univariate and multivariate statistical tests and online pathway databases. Relative to the WT, a total of nine and ten metabolites were significantly different in the Δmtp and complement strains, respectively. All nine significant metabolites were found in elevated levels in the Δmtp relative to the WT. Additionally, of the ten significant metabolites, eight were detected in lower levels and two were detected in higher levels in the complement relative to the WT. The absence of the MTP adhesin resulted in reduced virulence of M. tuberculosis leading to alterations in metabolites involved in carbon, fatty acid and amino acid metabolism during macrophage infection, suggesting that MTP plays an important role in the modulation of host metabolic activity. These findings support the prominent role of the MTP adhesin as a virulence factor as well as a promising biomarker for possible diagnostic and therapeutic intervention.
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Affiliation(s)
- Shinese Ashokcoomar
- Medical Microbiology, School of Laboratory Medicine and Medical Sciences, College of Health Sciences, University of KwaZulu-Natal, 1st Floor Doris Duke Medical Research Institute, Congella, Private Bag 7, Durban, 4013, South Africa.
| | - Du Toit Loots
- Human Metabolomics, North-West University, Potchefstroom, Private Bag X6001, Box 269, 2531, South Africa.
| | - Derylize Beukes
- Human Metabolomics, North-West University, Potchefstroom, Private Bag X6001, Box 269, 2531, South Africa.
| | - Mari van Reenen
- Human Metabolomics, North-West University, Potchefstroom, Private Bag X6001, Box 269, 2531, South Africa.
| | - Balakrishna Pillay
- Microbiology, School of Life Sciences, College of Agriculture, Engineering and Science, University of KwaZulu-Natal, Westville Campus, Private Bag X54001, Durban. 4000, South Africa.
| | - Manormoney Pillay
- Medical Microbiology, School of Laboratory Medicine and Medical Sciences, College of Health Sciences, University of KwaZulu-Natal, 1st Floor Doris Duke Medical Research Institute, Congella, Private Bag 7, Durban, 4013, South Africa.
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Treatment of Yersinia similis with the cationic lipid DOTAP enhances adhesion to and invasion into intestinal epithelial cells - A proof-of-principle study. Biochem Biophys Res Commun 2020; 525:378-383. [PMID: 32098674 DOI: 10.1016/j.bbrc.2020.02.081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 02/11/2020] [Indexed: 11/21/2022]
Abstract
The monocationic quaternary surfactant DOTAP has been used for the delivery of nucleic acids and peptides into mammalian cells. This study tested the applicability of DOTAP for the enhancement of adhesion and invasion frequencies of Yersinia (Y.) similis to enable the analysis of the effects of low-pathogenic bacteria on intestinal epithelial cells. Incubation of Y. similis with DOTAP ahead of infection of C2BBe1 intestinal epithelial cells increased invasion and adhesion frequency four- and five-fold, respectively, in plating assays. Proteomic approaches confirmed the increased bacterial load on infected cells: analysis of protein extracts by two-dimensional difference gel electrophoresis (2D-DIGE) revealed higher amounts of bacterial proteins present in the cells infected with DOTAP-treated bacteria. MALDI-TOF mass spectrometry of selected spots from gel-separated protein extracts confirmed the presence of both bacterial and human cell proteins in the samples. Label-free quantitative proteomics analysis identified 1170 human cell proteins and 699 bacterial proteins. Three times more bacterial proteins (279 vs. 93) were detected in C2BBe1 cells infected with DOTAP-treated bacteria compared to infections with untreated bacteria. Infections with DOTAP-treated Y. similis led to a significant upregulation of the stress-inducible ubiquitin-conjugating enzyme UBE2M in C2BBe1 cells. This points towards a stronger impact of the stress and infection responsive transcription factor AP-1 by enhanced bacterial load. DOTAP-treatment of uninfected C2BBe1 cells led to a significant downregulation of the transmembrane trafficking protein TMED10. The application of DOTAP could be helpful for investigating the impact of otherwise low adherent or invasive bacteria on cultivated mammalian cells without utilisation of genetic modifications.
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16
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King MM, Kayastha BB, Franklin MJ, Patrauchan MA. Calcium Regulation of Bacterial Virulence. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1131:827-855. [PMID: 31646536 DOI: 10.1007/978-3-030-12457-1_33] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Calcium (Ca2+) is a universal signaling ion, whose major informational role shaped the evolution of signaling pathways, enabling cellular communications and responsiveness to both the intracellular and extracellular environments. Elaborate Ca2+ regulatory networks have been well characterized in eukaryotic cells, where Ca2+ regulates a number of essential cellular processes, ranging from cell division, transport and motility, to apoptosis and pathogenesis. However, in bacteria, the knowledge on Ca2+ signaling is still fragmentary. This is complicated by the large variability of environments that bacteria inhabit with diverse levels of Ca2+. Yet another complication arises when bacterial pathogens invade a host and become exposed to different levels of Ca2+ that (1) are tightly regulated by the host, (2) control host defenses including immune responses to bacterial infections, and (3) become impaired during diseases. The invading pathogens evolved to recognize and respond to the host Ca2+, triggering the molecular mechanisms of adhesion, biofilm formation, host cellular damage, and host-defense resistance, processes enabling the development of persistent infections. In this review, we discuss: (1) Ca2+ as a determinant of a host environment for invading bacterial pathogens, (2) the role of Ca2+ in regulating main events of host colonization and bacterial virulence, and (3) the molecular mechanisms of Ca2+ signaling in bacterial pathogens.
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Affiliation(s)
- Michelle M King
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, USA
| | - Biraj B Kayastha
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, USA
| | - Michael J Franklin
- Department of Microbiology and Center for Biofilm Engineering, Montana State University, Bozeman, MT, USA
| | - Marianna A Patrauchan
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, USA.
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Zakharevich NV, Nezametdinova VZ, Averina OV, Chekalina MS, Alekseeva MG, Danilenko VN. Complete Genome Sequence of Bifidobacterium angulatum GT102: Potential Genes and Systems of Communication with Host. RUSS J GENET+ 2019. [DOI: 10.1134/s1022795419070160] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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18
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Engevik MA, Luk B, Chang-Graham AL, Hall A, Herrmann B, Ruan W, Endres BT, Shi Z, Garey KW, Hyser JM, Versalovic J. Bifidobacterium dentium Fortifies the Intestinal Mucus Layer via Autophagy and Calcium Signaling Pathways. mBio 2019; 10:e01087-19. [PMID: 31213556 PMCID: PMC6581858 DOI: 10.1128/mbio.01087-19] [Citation(s) in RCA: 144] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 05/11/2019] [Indexed: 02/07/2023] Open
Abstract
Much remains unknown about how the intestinal microbiome interfaces with the protective intestinal mucus layer. Bifidobacterium species colonize the intestinal mucus layer and can modulate mucus production by goblet cells. However, select Bifidobacterium strains can also degrade protective glycans on mucin proteins. We hypothesized that the human-derived species Bifidobacterium dentium would increase intestinal mucus synthesis and expulsion, without extensive degradation of mucin glycans. In silico data revealed that B. dentium lacked the enzymes necessary to extensively degrade mucin glycans. This finding was confirmed by demonstrating that B. dentium could not use naive mucin glycans as primary carbon sources in vitro To examine B. dentium mucus modulation in vivo, Swiss Webster germfree mice were monoassociated with live or heat-killed B. dentium Live B. dentium-monoassociated mice exhibited increased colonic expression of goblet cell markers Krüppel-like factor 4 (Klf4), Trefoil factor 3 (Tff3), Relm-β, Muc2, and several glycosyltransferases compared to both heat-killed B. dentium and germfree counterparts. Likewise, live B. dentium-monoassociated colon had increased acidic mucin-filled goblet cells, as denoted by Periodic Acid-Schiff-Alcian Blue (PAS-AB) staining and MUC2 immunostaining. In vitro, B. dentium-secreted products, including acetate, were able to increase MUC2 levels in T84 cells. We also identified that B. dentium-secreted products, such as γ-aminobutyric acid (GABA), stimulated autophagy-mediated calcium signaling and MUC2 release. This work illustrates that B. dentium is capable of enhancing the intestinal mucus layer and goblet cell function via upregulation of gene expression and autophagy signaling pathways, with a net increase in mucin production.IMPORTANCE Microbe-host interactions in the intestine occur along the mucus-covered epithelium. In the gastrointestinal tract, mucus is composed of glycan-covered proteins, or mucins, which are secreted by goblet cells to form a protective gel-like structure above the epithelium. Low levels of mucin or alterations in mucin glycans are associated with inflammation and colitis in mice and humans. Although current literature links microbes to the modulation of goblet cells and mucins, the molecular pathways involved are not yet fully understood. Using a combination of gnotobiotic mice and mucus-secreting cell lines, we have identified a human-derived microbe, Bifidobacterium dentium, which adheres to intestinal mucus and secretes metabolites that upregulate the major mucin MUC2 and modulate goblet cell function. Unlike other Bifidobacterium species, B. dentium does not extensively degrade mucin glycans and cannot grow on mucin alone. This work points to the potential of using B. dentium and similar mucin-friendly microbes as therapeutic agents for intestinal disorders with disruptions in the mucus barrier.
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Affiliation(s)
- Melinda A Engevik
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas, USA
- Department of Pathology, Texas Children's Hospital, Houston, Texas, USA
| | - Berkley Luk
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas, USA
- Department of Pathology, Texas Children's Hospital, Houston, Texas, USA
| | - Alexandra L Chang-Graham
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, USA
| | - Anne Hall
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas, USA
- Department of Pathology, Texas Children's Hospital, Houston, Texas, USA
| | - Beatrice Herrmann
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas, USA
- Department of Pathology, Texas Children's Hospital, Houston, Texas, USA
| | - Wenly Ruan
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas, USA
- Department of Pathology, Texas Children's Hospital, Houston, Texas, USA
| | - Bradley T Endres
- Department of Pharmacy Practice and Translational Research, University of Houston College of Pharmacy, Houston, Texas, USA
| | - Zhongcheng Shi
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas, USA
- Department of Pathology, Texas Children's Hospital, Houston, Texas, USA
| | - Kevin W Garey
- Department of Pharmacy Practice and Translational Research, University of Houston College of Pharmacy, Houston, Texas, USA
| | - Joseph M Hyser
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, USA
| | - James Versalovic
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas, USA
- Department of Pathology, Texas Children's Hospital, Houston, Texas, USA
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Zhu Z, Dong C, Weng S, He J. Identification of outer membrane protein TolC as the major adhesin and potential vaccine candidate for Vibrio harveyi in hybrid grouper, Epinephelus fuscoguttatus (♀) × E. lanceolatus (♂). FISH & SHELLFISH IMMUNOLOGY 2019; 86:143-151. [PMID: 30453046 DOI: 10.1016/j.fsi.2018.11.037] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 11/13/2018] [Accepted: 11/15/2018] [Indexed: 05/21/2023]
Abstract
Vibrio harveyi is a serious pathogen of scale drop and muscle necrosis disease in marine commercial fishes. Adhesion to and colonization of the host cells surfaces is the first and crucial step for pathogenic bacterial infection, which is usually mediated by outer membrane proteins (Omps). The objectives of this study were to identify the major adhesin in Omps that plays the essential role in adhesion of V. harveyi to the host cells, and to assess the potential of this adhesin as a vaccine candidate for V. harveyi infection. We observed that pathogenic V. harveyi adhered to the surface of grouper embryonic cells (GEM cells) and induced apoptosis of them. Native Omps were extracted from nine different V. harveyi strains, and five common Omp bands were isolated by SDS-PAGE analysis. Western blot analysis and an anti-native Omp antibodies blocking assay indicated that one strong and several weak immunoreactivity Omps bands presence. Next, a total of five Omps, including TolC, Agg (Agglutination protein), Omp47, Fla (Flagellin), and OmpW, were identified and their encoding genes were cloned, characterized, and expressed in E. coli. The purified recombinant TolC could competitively inhibit the invasion of V. harveyi to GEM cells in vitro, and anti-TolC antibody also could significantly block the adhesion of V. harveyi to GEM cells. When used to immunize hybrid groupers, the recombinant TolC could confer significant protection to fish against experimental V. harveyi challenge. These data suggested that outer membrane protein TolC functions as a major adhesin in V. harveyi and could be a potential vaccine candidate for V. harveyi infection.
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Affiliation(s)
- Zhiming Zhu
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Sciences, Sun Yat-sen University, Guangzhou, 510275, PR China; State Key Laboratory of Biocontrol / MOE Key Laboratory of Aquatic Product Safety, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, PR China; Institute of Aquatic Economic Animals, and Guangdong Province Key Laboratory for Aquatic Economic Animals, Sun Yat-sen University, Guangzhou, 510275, PR China
| | - Chuanfu Dong
- State Key Laboratory of Biocontrol / MOE Key Laboratory of Aquatic Product Safety, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, PR China; Institute of Aquatic Economic Animals, and Guangdong Province Key Laboratory for Aquatic Economic Animals, Sun Yat-sen University, Guangzhou, 510275, PR China.
| | - Shaoping Weng
- State Key Laboratory of Biocontrol / MOE Key Laboratory of Aquatic Product Safety, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, PR China; Institute of Aquatic Economic Animals, and Guangdong Province Key Laboratory for Aquatic Economic Animals, Sun Yat-sen University, Guangzhou, 510275, PR China
| | - Jianguo He
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Sciences, Sun Yat-sen University, Guangzhou, 510275, PR China; State Key Laboratory of Biocontrol / MOE Key Laboratory of Aquatic Product Safety, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, PR China; Institute of Aquatic Economic Animals, and Guangdong Province Key Laboratory for Aquatic Economic Animals, Sun Yat-sen University, Guangzhou, 510275, PR China.
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20
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Sijbrandij T, Ligtenberg AJ, Nazmi K, van den Keijbus PAM, Veerman ECI, Bolscher JGM, Bikker FJ. LFchimera protects HeLa cells from invasion by Yersinia spp. in vitro. Biometals 2018; 31:941-950. [PMID: 30136243 PMCID: PMC6245033 DOI: 10.1007/s10534-018-0136-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 08/17/2018] [Indexed: 11/30/2022]
Abstract
Yersinia pestis is the causative agent of plague. As adequate antibiotic treatment falls short and currently no effective vaccine is available, alternative therapeutic strategies are needed. In order to contribute to solving this problem we investigated the therapeutic potential of the peptide construct LFchimera against the safer-to-handle Y. pestis simulants Yersinia enterocolitica and Yersinia pseudotuberculosis in vitro. LFchimera is a heterodimeric peptide construct mimicking two antimicrobial domains of bovine lactoferrin, i.e. lactoferrampin and lactoferricin. LFchimera has been shown to be a potent antimicrobial peptide against a variety of bacteria in vitro and in vivo. Also Y. enterocolitica and Y. pseudotuberculosis have been shown to be susceptible for LFchimera in vitro. As Yersiniae spp. adhere to and invade host cells upon infection, we here investigated the effects of LFchimera on these processes. It was found that LFchimera has the capacity to inhibit host-cell invasion by Yersiniae spp. in vitro. This effect appeared to be host-cell mediated, not bacteria-mediated. Furthermore it was found that exposure of human HeLa epithelial cells to both LFchimera and the bacterial strains evoked a pro-inflammatory cytokine release from the cells in vitro.
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Affiliation(s)
- Tjitske Sijbrandij
- Department of Oral Biochemistry, Academic Centre for Dentistry Amsterdam, University of Amsterdam and VU University Amsterdam, Gustav Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands
| | - Antoon J Ligtenberg
- Department of Oral Biochemistry, Academic Centre for Dentistry Amsterdam, University of Amsterdam and VU University Amsterdam, Gustav Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands
| | - Kamran Nazmi
- Department of Oral Biochemistry, Academic Centre for Dentistry Amsterdam, University of Amsterdam and VU University Amsterdam, Gustav Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands
| | - Petra A M van den Keijbus
- Department of Oral Biochemistry, Academic Centre for Dentistry Amsterdam, University of Amsterdam and VU University Amsterdam, Gustav Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands
| | - Enno C I Veerman
- Department of Oral Biochemistry, Academic Centre for Dentistry Amsterdam, University of Amsterdam and VU University Amsterdam, Gustav Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands
| | - Jan G M Bolscher
- Department of Oral Biochemistry, Academic Centre for Dentistry Amsterdam, University of Amsterdam and VU University Amsterdam, Gustav Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands
| | - Floris J Bikker
- Department of Oral Biochemistry, Academic Centre for Dentistry Amsterdam, University of Amsterdam and VU University Amsterdam, Gustav Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands.
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Böhringer M, Rakin A, Neubauer H, Sprague LD. Development of a flow cytometry based assay to determine the invasion of enteropathogenic Yersiniae into C2BBe1 cells. J Microbiol Methods 2018; 149:29-35. [PMID: 29698692 DOI: 10.1016/j.mimet.2018.04.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 04/19/2018] [Accepted: 04/22/2018] [Indexed: 10/17/2022]
Abstract
A rapid method was developed to determine the invasion frequency of enteropathogenic Yersinia into intestinal C2BBe1 cells by means of flow cytometry. Bacteria are labelled with a thiol-cleavable amine-reactive biotin and subsequently incubated with the fluorochrome-labelled biotin-ligand neutravidin. After infection of the intestinal cells with the labelled bacteria, the neutravidin-coupled fluorochrome is detached by breaking up the linker through reduction of the disulphide. Despite reduced adhesion and invasion frequencies of the labelled bacteria into C2BBe1 cells this procedure offers the basis for the development of a fast single-step staining protocol for the recovery of invading bacteria in in a host-pathogen system for further transcriptome or proteome analysis.
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Affiliation(s)
- Michael Böhringer
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute for Bacterial Infections and Zoonoses, Naumburger Str. 96a, D-07743 Jena, Germany.
| | - Alexander Rakin
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute for Bacterial Infections and Zoonoses, Naumburger Str. 96a, D-07743 Jena, Germany.
| | - Heinrich Neubauer
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute for Bacterial Infections and Zoonoses, Naumburger Str. 96a, D-07743 Jena, Germany.
| | - Lisa D Sprague
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute for Bacterial Infections and Zoonoses, Naumburger Str. 96a, D-07743 Jena, Germany.
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Solanki V, Tiwari M, Tiwari V. Host-bacteria interaction and adhesin study for development of therapeutics. Int J Biol Macromol 2018; 112:54-64. [PMID: 29414732 DOI: 10.1016/j.ijbiomac.2018.01.151] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 01/17/2018] [Accepted: 01/21/2018] [Indexed: 12/15/2022]
Abstract
Host-pathogen interaction is one of the most important areas of study to understand the adhesion of the pathogen to the host organisms. To adhere on the host cell surface, bacteria assemble the diverse adhesive structures on its surface, which play a foremost role in targeting to the host cell. We have highlighted different bacterial adhesins which are either protein mediated or glycan mediated. The present article listed examples of different bacterial adhesin proteins involved in the interactions with their host, types and subtypes of the fimbriae and non-fimbriae bacterial adhesins. Different bacterial surface adhesin subunits interact with host via different host surface biomolecules. We have also discussed the interactome of some of the pathogens with their host. Therefore, the present study will help researchers to have a detailed understanding of different interacting bacterial adhesins and henceforth, develop new therapies, adhesin specific antibodies and vaccines, which can effectively control pathogenicity of the pathogens.
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Affiliation(s)
- Vandana Solanki
- Department of Biochemistry, Central University of Rajasthan, Ajmer 305817, India
| | - Monalisa Tiwari
- Department of Biochemistry, Central University of Rajasthan, Ajmer 305817, India
| | - Vishvanath Tiwari
- Department of Biochemistry, Central University of Rajasthan, Ajmer 305817, India.
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23
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Hu YF, Zhao D, Yu XL, Hu YL, Li RC, Ge M, Xu TQ, Liu XB, Liao HY. Identification of Bacterial Surface Antigens by Screening Peptide Phage Libraries Using Whole Bacteria Cell-Purified Antisera. Front Microbiol 2017; 8:82. [PMID: 28184219 PMCID: PMC5266700 DOI: 10.3389/fmicb.2017.00082] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 01/11/2017] [Indexed: 01/10/2023] Open
Abstract
Bacterial surface proteins can be good vaccine candidates. In the present study, we used polyclonal antibodies purified with intact Erysipelothrix rhusiopthiae to screen phage-displayed random dodecapeptide and loop-constrained heptapeptide libraries, which led to the identification of mimotopes. Homology search of the mimotope sequences against E. rhusiopthiae-encoded ORF sequences revealed 14 new antigens that may localize on the surface of E. rhusiopthiae. When these putative surface proteins were used to immunize mice, 9/11 antigens induced protective immunity. Thus, we have demonstrated that a combination of using the whole bacterial cells to purify antibodies and using the phage-displayed peptide libraries to determine the antigen specificities of the antibodies can lead to the discovery of novel bacterial surface antigens. This can be a general approach for identifying surface antigens for other bacterial species.
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Affiliation(s)
- Yun-Fei Hu
- College of Veterinary Medicine, Preventive Veterinary Medicine, Hunan Agricultural University Changsha, China
| | - Dun Zhao
- College of Veterinary Medicine, Preventive Veterinary Medicine, Hunan Agricultural University Changsha, China
| | - Xing-Long Yu
- College of Veterinary Medicine, Preventive Veterinary Medicine, Hunan Agricultural University Changsha, China
| | - Yu-Li Hu
- College of Veterinary Medicine, Preventive Veterinary Medicine, Hunan Agricultural University Changsha, China
| | - Run-Cheng Li
- College of Veterinary Medicine, Preventive Veterinary Medicine, Hunan Agricultural University Changsha, China
| | - Meng Ge
- College of Veterinary Medicine, Preventive Veterinary Medicine, Hunan Agricultural University Changsha, China
| | - Tian-Qi Xu
- College of Veterinary Medicine, Preventive Veterinary Medicine, Hunan Agricultural University Changsha, China
| | - Xiao-Bo Liu
- College of Veterinary Medicine, Preventive Veterinary Medicine, Hunan Agricultural University Changsha, China
| | - Hua-Yuan Liao
- College of Veterinary Medicine, Preventive Veterinary Medicine, Hunan Agricultural University Changsha, China
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24
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Westermann C, Gleinser M, Corr SC, Riedel CU. A Critical Evaluation of Bifidobacterial Adhesion to the Host Tissue. Front Microbiol 2016; 7:1220. [PMID: 27547201 PMCID: PMC4974247 DOI: 10.3389/fmicb.2016.01220] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 07/22/2016] [Indexed: 01/15/2023] Open
Abstract
Bifidobacteria are common inhabitants of the human gastrointestinal tract that, despite a long history of research, have not shown any pathogenic potential whatsoever. By contrast, some bifidobacteria are associated with a number of health-related benefits for the host. The reported beneficial effects of bifidobacteria include competitive exclusion of pathogens, alleviation of symptoms of irritable bowel syndrome and inflammatory bowel disease, and modulation of intestinal and systemic immune responses. Based on these effects, bifidobacteria are widely used as probiotics by pharmaceutical and dairy industries. In order to exert a beneficial effect bifidobacteria have to, at least transiently, colonize the host in a sufficient population size. Besides other criteria such as resistance to manufacturing processes and intestinal transit, potential probiotic bacteria are tested for adhesion to the host structures including intestinal epithelial cells, mucus, and extracellular matrix components. In the present review article, we summarize the current knowledge on bifidobacterial structures that mediate adhesion to host tissue and compare these to similar structures of pathogenic bacteria. This reveals that most of the adhesive structures and mechanisms involved in adhesion of bifidobacteria to host tissue are similar or even identical to those employed by pathogens to cause disease. It is thus reasonable to assume that these structures and mechanisms are equally important for commensal or probiotic bacteria and play a similar role in the beneficial effects exerted by bifidobacteria.
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Affiliation(s)
| | - Marita Gleinser
- Institute of Microbiology and Biotechnology, University of Ulm Ulm, Germany
| | - Sinéad C Corr
- Department of Microbiology, Moyne Institute of Preventative Medicine, School of Genetics and Microbiology, Trinity College Dublin Dublin, Ireland
| | - Christian U Riedel
- Institute of Microbiology and Biotechnology, University of Ulm Ulm, Germany
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Zhang X, Yang T, Cao J, Sun J, Dai W, Zhang L. Mucosal immunization with purified OmpA elicited protective immunity against infections caused by multidrug-resistant Acinetobacter baumannii. Microb Pathog 2016; 96:20-5. [PMID: 27133268 DOI: 10.1016/j.micpath.2016.04.019] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 04/10/2016] [Accepted: 04/28/2016] [Indexed: 12/12/2022]
Abstract
Multidrug-resistant Acinetobacter baumannii (A. baumannii) is a rapidly emerging pathogen causing infections with high mortality rates due to inadequate medical treatment. New ways to prevent and treat such infections are of a critical medical need. In this study, intranasal vaccination with A. baumannii outer membrane protein A (OmpA) induced both systemic and mucosal antibodies. After challenge intraperitoneally by clinical strains of multidrug-resistant A. baumannii, mice immunized with OmpA had a significantly higher survival rate than control mice. The OmpA protein level tested positive by western blot in clinical strains of A. baumannii. Furthermore, characterization of human sera for anti-OmpA immunoglobulin G (IgG) antibody levels demonstrated that OmpA protein was immunogenic in healthy individuals and patients with A. baumannii invasive infections. In conclusion, to the best of our knowledge, this is the first study protective efficacy of mucosal immunization with OmpA as a protein antigen against multidrug-resistant A. Baumannii.
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Affiliation(s)
- Xiaojiao Zhang
- Department of Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China
| | - Tianxiang Yang
- Department of Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China
| | - Ju Cao
- Department of Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China
| | - Jide Sun
- Department of Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China
| | - Wei Dai
- Department of Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China
| | - Liping Zhang
- Department of Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China.
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26
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Pilatti L, Boldrin de Paiva J, Rojas TCG, Leite JL, Conceição RA, Nakazato G, Dias da Silveira W. The virulence factor ychO has a pleiotropic action in an Avian Pathogenic Escherichia coli (APEC) strain. BMC Microbiol 2016; 16:35. [PMID: 26965678 PMCID: PMC4787180 DOI: 10.1186/s12866-016-0654-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 03/02/2016] [Indexed: 02/04/2023] Open
Abstract
Background Avian pathogenic Escherichia coli strains cause extraintestinal diseases in birds, leading to substantial economic losses to the poultry industry worldwide. Bacteria that invade cells can overcome the host humoral immune response, resulting in a higher pathogenicity potential. Invasins are members of a large family of outer membrane proteins that allow pathogen invasion into host cells by interacting with specific receptors on the cell surface. Results An in silico analysis of the genome of a septicemic APEC strain (SEPT362) demonstrated the presence of a putative invasin homologous to the ychO gene from E. coli str. K-12 substr. MG1655. In vitro and in vivo assays comparing a mutant strain carrying a null mutation of this gene, a complemented strain, and its counterpart wild-type strain showed that ychO plays a role in the pathogenicity of APEC strain SEPT362. In vitro assays demonstrated that the mutant strain exhibited significant decreases in bacterial adhesiveness and invasiveness in chicken cells and biofilm formation. In vivo assay indicated a decrease in pathogenicity of the mutant strain. Moreover, transcriptome analysis demonstrated that the ychO deletion affected the expression of 426 genes. Among the altered genes, 93.66 % were downregulated in the mutant, including membrane proteins and metabolism genes. Conclusion The results led us to propose that gene ychO contributes to the pathogenicity of APEC strain SEPT362 influencing, in a pleiotropic manner, many biological characteristics, such as adhesion and invasion of in vitro cultured cells, biofilm formation and motility, which could be due to the possible membrane location of this protein. All of these results suggest that the absence of gene ychO would influence the virulence of the APEC strain herein studied.
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Affiliation(s)
- Livia Pilatti
- Department of Genetics, Evolution and Bioagents, Institute of Biology (P.O.Box: 6109), State University of Campinas - UNICAMP (ZIP Code 13083-970), Campinas, São Paulo, Brazil
| | - Jacqueline Boldrin de Paiva
- Department of Genetics, Evolution and Bioagents, Institute of Biology (P.O.Box: 6109), State University of Campinas - UNICAMP (ZIP Code 13083-970), Campinas, São Paulo, Brazil
| | - Thaís Cabrera Galvão Rojas
- Department of Genetics, Evolution and Bioagents, Institute of Biology (P.O.Box: 6109), State University of Campinas - UNICAMP (ZIP Code 13083-970), Campinas, São Paulo, Brazil
| | - Janaína Luisa Leite
- Department of Genetics, Evolution and Bioagents, Institute of Biology (P.O.Box: 6109), State University of Campinas - UNICAMP (ZIP Code 13083-970), Campinas, São Paulo, Brazil
| | - Rogério Arcuri Conceição
- Department of Genetics, Evolution and Bioagents, Institute of Biology (P.O.Box: 6109), State University of Campinas - UNICAMP (ZIP Code 13083-970), Campinas, São Paulo, Brazil
| | - Gerson Nakazato
- Department of Microbiology, Center of Biological Sciences, State University of Londrina (UEL), Londrina, Paraná, Brazil
| | - Wanderley Dias da Silveira
- Department of Genetics, Evolution and Bioagents, Institute of Biology (P.O.Box: 6109), State University of Campinas - UNICAMP (ZIP Code 13083-970), Campinas, São Paulo, Brazil.
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Fernandes LG, Siqueira GH, Teixeira ARF, Silva LP, Figueredo JM, Cosate MR, Vieira ML, Nascimento ALTO. Leptospira spp.: Novel insights into host-pathogen interactions. Vet Immunol Immunopathol 2015; 176:50-7. [PMID: 26727033 DOI: 10.1016/j.vetimm.2015.12.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 12/09/2015] [Accepted: 12/10/2015] [Indexed: 01/30/2023]
Abstract
Leptospirosis is a widespread zoonosis caused by pathogenic Leptospira spp. It is an important infectious disease that affects humans and animals. The disease causes economic losses as it affects livestock, with decreased milk production and death. Our group is investigating the genome sequences of L. interrogans targeting surface-exposed proteins because, due to their location, these proteins are capable to interact with several host components that could allow establishment of the infection. These interactions may involve adhesion of the bacteria to extracellular matrix (ECM) components and, hence, help bacterial colonization. The bacteria could also react with the host fibrinolytic system and/or with the coagulation cascade components, such as, plasminogen (PLG) and fibrinogen (Fg), respectively. The binding with the first system generates plasmin (PLA), increasing the proteolytic power of the bacteria, while the second interferes with clotting in a thrombin-catalyzed reaction, which may promote hemorrhage foci and increase bacterial dissemination. Interaction with the complement system negative regulators may help bacteria to evade the host immune system, facilitating the invasion. This work compiles the main described leptospiral proteins that could act as adhesins, as PLG and fibrinogen receptors and as complement regulator binding proteins. We present models in which we suggest possible mechanisms of how leptospires might colonize and invade host tissues, causing the disease. Understanding leptospiral pathogenesis will help to identify antigen candidates that would contribute to the development of more effective vaccines and diagnostic tests.
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Affiliation(s)
- Luis G Fernandes
- Centro de Biotecnologia, Instituto Butantan, Avenida Vital Brazil, 1500, 05503-900, São Paulo, SP, Brazil; Programa de Pós Graduação Interunidades em Biotecnologia, Instituto de Ciências Biomédicas, USP, Avenida Prof. Lineu Prestes, 1730, 05508-900, São Paulo, SP, Brazil
| | - Gabriela H Siqueira
- Centro de Biotecnologia, Instituto Butantan, Avenida Vital Brazil, 1500, 05503-900, São Paulo, SP, Brazil; Programa de Pós Graduação Interunidades em Biotecnologia, Instituto de Ciências Biomédicas, USP, Avenida Prof. Lineu Prestes, 1730, 05508-900, São Paulo, SP, Brazil
| | - Aline R F Teixeira
- Centro de Biotecnologia, Instituto Butantan, Avenida Vital Brazil, 1500, 05503-900, São Paulo, SP, Brazil; Programa de Pós Graduação Interunidades em Biotecnologia, Instituto de Ciências Biomédicas, USP, Avenida Prof. Lineu Prestes, 1730, 05508-900, São Paulo, SP, Brazil
| | - Lucas P Silva
- Centro de Biotecnologia, Instituto Butantan, Avenida Vital Brazil, 1500, 05503-900, São Paulo, SP, Brazil; Programa de Pós Graduação Interunidades em Biotecnologia, Instituto de Ciências Biomédicas, USP, Avenida Prof. Lineu Prestes, 1730, 05508-900, São Paulo, SP, Brazil
| | - Jupciana M Figueredo
- Centro de Biotecnologia, Instituto Butantan, Avenida Vital Brazil, 1500, 05503-900, São Paulo, SP, Brazil; Programa de Pós Graduação Interunidades em Biotecnologia, Instituto de Ciências Biomédicas, USP, Avenida Prof. Lineu Prestes, 1730, 05508-900, São Paulo, SP, Brazil
| | - Maria R Cosate
- Centro de Biotecnologia, Instituto Butantan, Avenida Vital Brazil, 1500, 05503-900, São Paulo, SP, Brazil
| | - Monica L Vieira
- Centro de Biotecnologia, Instituto Butantan, Avenida Vital Brazil, 1500, 05503-900, São Paulo, SP, Brazil
| | - Ana L T O Nascimento
- Centro de Biotecnologia, Instituto Butantan, Avenida Vital Brazil, 1500, 05503-900, São Paulo, SP, Brazil; Programa de Pós Graduação Interunidades em Biotecnologia, Instituto de Ciências Biomédicas, USP, Avenida Prof. Lineu Prestes, 1730, 05508-900, São Paulo, SP, Brazil.
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28
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Genome of the facultative scuticociliatosis pathogen Pseudocohnilembus persalinus provides insight into its virulence through horizontal gene transfer. Sci Rep 2015; 5:15470. [PMID: 26486372 PMCID: PMC4614350 DOI: 10.1038/srep15470] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 09/28/2015] [Indexed: 01/22/2023] Open
Abstract
Certain ciliates of the subclass Scuticociliatia (scuticociliates) are facultative parasites of fishes in which they cause a suite of diseases collectively termed scuticociliatosis. Hitherto, comparatively little was known about genetics and genomics of scuticociliates or the mechanism of scuticociliatosis. In this study, a laboratory culture of the facultatively pathogenic scuticociliate Pseudocohnilembus persalinus was established and its genome sequenced, giving the first genome of a marine ciliate. Genome-wide horizontal gene transfer (HGT) analysis showed P. persalinus has acquired many unique prokaryote-derived genes that potentially contribute to the virulence of this organism, including cell adhesion, hemolysis and heme utilization genes. These findings give new insights into our understanding of the pathology of scuticociliates.
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Shahid SA, Nagaraj M, Chauhan N, Franks TW, Bardiaux B, Habeck M, Orwick-Rydmark M, Linke D, van Rossum BJ. Festkörper-NMR-Studien an der Membrananker-Domäne von YadA in der bakteriellen Außenmembran. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201505506] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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30
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Shahid SA, Nagaraj M, Chauhan N, Franks TW, Bardiaux B, Habeck M, Orwick-Rydmark M, Linke D, van Rossum BJ. Solid-state NMR Study of the YadA Membrane-Anchor Domain in the Bacterial Outer Membrane. Angew Chem Int Ed Engl 2015; 54:12602-6. [PMID: 26332158 DOI: 10.1002/anie.201505506] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 07/17/2015] [Indexed: 12/12/2022]
Abstract
MAS-NMR was used to study the structure and dynamics at ambient temperatures of the membrane-anchor domain of YadA (YadA-M) in a pellet of the outer membrane of E. coli in which it was expressed. YadA is an adhesin from the pathogen Yersinia enterocolitica that is involved in interactions with the host cell, and it is a model protein for studying the autotransport process. Existing assignments were sucessfully transferred to a large part of the YadA-M protein in the E. coli lipid environment by using (13) C-(13) C DARR and PDSD spectra at different mixing times. The chemical shifts in most regions of YadA-M are unchanged relative to those in microcrystalline YadA-M preparations from which a structure has previously been solved, including the ASSA region that is proposed to be involved in transition-state hairpin formation for transport of the soluble domain. Comparisons of the dynamics between the microcrystalline and membrane-embedded samples indicate greater flexibility of the ASSA region in the outer-membrane preparation at physiological temperatures. This study will pave the way towards MAS-NMR structure determination of membrane proteins, and a better understanding of functionally important dynamic residues in native membrane environments.
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Affiliation(s)
- Shakeel A Shahid
- Max-Planck-Institute for Developmental Biology, Department 1, Tübingen (Germany).,Leibniz-Institut für Molekulare Pharmakologie FMP, Robert-Rössle-Str. 10, 13125 Berlin (Germany)
| | - Madhu Nagaraj
- Leibniz-Institut für Molekulare Pharmakologie FMP, Robert-Rössle-Str. 10, 13125 Berlin (Germany)
| | - Nandini Chauhan
- University of Oslo, Department of Biosciences, POBox 1066 Blindern, 0316 Oslo (Norway)
| | - Trent W Franks
- Leibniz-Institut für Molekulare Pharmakologie FMP, Robert-Rössle-Str. 10, 13125 Berlin (Germany)
| | - Benjamin Bardiaux
- Unité de Bioinformatique Structurale, CNRS UMR3528, Institut Pasteur, Paris (France)
| | - Michael Habeck
- Felix-Bernstein Institute for Mathematical Statistics, Georg-August-Universität Göttingen (Germany).,Max Planck Institute for Biophysical Chemistry, Göttingen (Germany)
| | | | - Dirk Linke
- Max-Planck-Institute for Developmental Biology, Department 1, Tübingen (Germany). .,University of Oslo, Department of Biosciences, POBox 1066 Blindern, 0316 Oslo (Norway).
| | - Barth-J van Rossum
- Leibniz-Institut für Molekulare Pharmakologie FMP, Robert-Rössle-Str. 10, 13125 Berlin (Germany).
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31
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Suzuki K, Moriguchi K, Yamamoto S. Horizontal DNA transfer from bacteria to eukaryotes and a lesson from experimental transfers. Res Microbiol 2015; 166:753-63. [PMID: 26291765 DOI: 10.1016/j.resmic.2015.08.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2015] [Revised: 08/04/2015] [Accepted: 08/05/2015] [Indexed: 11/15/2022]
Abstract
Horizontal gene transfer (HGT) is widespread among bacteria and plays a key role in genome dynamics. HGT is much less common in eukaryotes, but is being reported with increasing frequency in eukaryotes. The mechanism as to how eukaryotes acquired genes from distantly related organisms remains obscure yet. This paper cites examples of bacteria-derived genes found in eukaryotic organisms, and then describes experimental DNA transports to eukaryotes by bacterial type 4 secretion systems in optimized conditions. The mechanisms of the latter are efficient, quite reproducible in vitro and predictable, and thereby would provide insight into natural HGT and to the development of new research tools.
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32
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Biophysical analysis of anopheles gambiae leucine-rich repeat proteins APL1A1, APL1B [corrected] and APL1C and their interaction with LRIM1. PLoS One 2015; 10:e0118911. [PMID: 25775123 PMCID: PMC4361550 DOI: 10.1371/journal.pone.0118911] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 01/13/2015] [Indexed: 11/19/2022] Open
Abstract
Natural infection of Anopheles gambiae by malaria-causing Plasmodium parasites is significantly influenced by the APL1 genetic locus. The locus contains three closely related leucine-rich repeat (LRR) genes, APL1A, APL1B and APL1C. Multiple studies have reported the participation of APL1A-C in the immune response of A. gambiae to invasion by both rodent and human Plasmodium isolates. APL1C forms a heterodimer with the related LRR protein LRIM1 via a C-terminal coiled-coil domain that is also present in APL1A and APL1B. The LRIM1/APL1C heterodimer protects A. gambiae from infection by binding the complement-like protein TEP1 to form a stable and active immune complex. Here we report solution x-ray scatting data for the LRIM1/APL1C heterodimer, the oligomeric state of LRIM1/APL1 LRR domains in solution and the crystal structure of the APL1B LRR domain. The LRIM1/APL1C heterodimeric complex has a flexible and extended structure in solution. In contrast to the APL1A, APL1C and LRIM1 LRR domains, the APL1B LRR domain is a homodimer. The crystal structure of APL1B-LRR shows that the homodimer is formed by an N-terminal helix that complements for the absence of an N-terminal capping motif in APL1B, which is a unique distinction within the LRIM1/APL1 protein family. Full-length APL1A1 and APL1B form a stable complex with LRIM1. These results support a model in which APL1A1, APL1B and APL1C can all form an extended, flexible heterodimer with LRIM1, providing a repertoire of functional innate immune complexes to protect A. gambiae from a diverse array of pathogens.
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Rana A, Rub A, Akhter Y. Proteome-wide B and T cell epitope repertoires in outer membrane proteins of Mycobacterium avium subsp. paratuberculosis have vaccine and diagnostic relevance: a holistic approach. J Mol Recognit 2015; 28:506-20. [PMID: 25727233 DOI: 10.1002/jmr.2458] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Revised: 12/05/2014] [Accepted: 12/16/2014] [Indexed: 11/11/2022]
Abstract
Mycobacterium avium subsp. paratuberculosis (MAP) is an etiological agent of chronic inflammation of the intestine among ruminants and humans. Currently, there are no effective vaccines and sensitive diagnostic tests available for its control and detection. For this, it is of paramount importance to identify the MAP antigens, which may be immunologically recognized by the host immune system. To address this challenge, we performed identification of the immunogenic epitopes in the MAP outer membrane proteins (OMPs). We have previously identified 57 MAP proteins as OMPs [Rana A, Rub A, Akhter Y. 2014. Molecular BioSystems, 10:2329-2337] and have evaluated them for the epitope selection and analysis employing a computational approach. Thirty-five MAP OMPs are reported with nine-mer peptides showing high binding affinity to major histocompatibility complex (MHC) class I molecules and 28 MAP OMPs with 15-mer peptides of high binding affinity for MHC class II molecules. The presence of MHC binding epitopes indicates the potential cell-mediated immune response inducing capacity of these MAP OMPs in infected host. To further investigate the humoral response inducing properties of OMPs of MAP, we report potential B cell epitopes based on the sequences of peptide antigens and their molecular structures. We also report 10 proteins having epitopes for both B and T cells representing potential candidates which may invoke both humoral and cellular immune responses in the host. These findings will greatly accelerate and expedite the formulation of effective and cost-efficient vaccines and diagnostic tests against MAP infection.
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Affiliation(s)
- Aarti Rana
- School of Life Sciences, Central University of Himachal Pradesh, Shahpur, Kangra, Himachal Pradesh, 176206, India
| | - Abdur Rub
- Infection and Immunity Laboratory, Department of Biotechnology, Jamia Millia Islamia (A Central University), New Delhi,, 110025, India
| | - Yusuf Akhter
- School of Life Sciences, Central University of Himachal Pradesh, Shahpur, Kangra, Himachal Pradesh, 176206, India
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RovS and its associated signaling peptide form a cell-to-cell communication system required for Streptococcus agalactiae pathogenesis. mBio 2015; 6:mBio.02306-14. [PMID: 25604789 PMCID: PMC4324310 DOI: 10.1128/mbio.02306-14] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
UNLABELLED Bacteria can communicate with each other to coordinate their biological functions at the population level. In a previous study, we described a cell-to-cell communication system in streptococci that involves a transcriptional regulator belonging to the Rgg family and short hydrophobic peptides (SHPs) that act as signaling molecules. Streptococcus agalactiae, an opportunistic pathogenic bacterium responsible for fatal infections in neonates and immunocompromised adults, has one copy of the shp/rgg locus. The SHP-associated Rgg is called RovS in S. agalactiae. In this study, we found that the SHP/RovS cell-to-cell communication system is active in the strain NEM316 of S. agalactiae, and we identified different partners that are involved in this system, such as the Eep peptidase, the PptAB, and the OppA1-F oligopeptide transporters. We also identified a new target gene controlled by this system and reexamined the regulation of a previously proposed target gene, fbsA, in the context of the SHP-associated RovS system. Furthermore, our results are the first to indicate the SHP/RovS system specificity to host liver and spleen using a murine model, which demonstrates its implication in streptococci virulence. Finally, we observed that SHP/RovS regulation influences S. agalactiae's ability to adhere to and invade HepG2 hepatic cells. Hence, the SHP/RovS cell-to-cell communication system appears to be an essential mechanism that regulates pathogenicity in S. agalactiae and represents an attractive target for the development of new therapeutic strategies. IMPORTANCE Rgg regulators and their cognate pheromones, called small hydrophobic peptides (SHPs), are present in nearly all streptococcal species. The general pathways of the cell-to-cell communication system in which Rgg and SHP take part are well understood. However, many other players remain unidentified, and the direct targets of the system, as well as its link to virulence, remain unclear. Here, we identified the different players involved in the SHP/Rgg system in S. agalactiae, which is the leading agent of severe infections in human newborns. We have identified a direct target of the Rgg regulator in S. agalactiae (called RovS) and examined a previously proposed target, all in the context of associated SHP. For the first time, we have also demonstrated the implication of the SHP/RovS mechanism in virulence, as well as its host organ specificity. Thus, this cell-to-cell communication system may represent a future target for S. agalactiae disease treatment.
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Mansfield MJ, Adams JB, Doxey AC. Botulinum neurotoxin homologs in non-Clostridium species. FEBS Lett 2014; 589:342-8. [PMID: 25541486 DOI: 10.1016/j.febslet.2014.12.018] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 12/02/2014] [Accepted: 12/09/2014] [Indexed: 12/24/2022]
Abstract
Clostridial neurotoxins (CNTs) are the deadliest toxins known and the causative agents of botulism and tetanus. Despite their structural and functional complexity, no CNT homologs are currently known outside Clostridium. Here, we report the first homologs of Clostridium CNTs within the genome of the rice fermentation organism Weissella oryzae SG25. One gene in W. oryzae S25 encodes a protein with a four-domain architecture and HExxH protease motif common to botulinum neurotoxins (BoNTs). An adjacent gene with partial similarity to CNTs is also present, and both genes seem to have been laterally transferred into the W. oryzae genome from an unknown source. Identification of mobile, CNT-related genes outside of Clostridium has implications for our understanding of the evolution of this important toxin family.
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Affiliation(s)
- Michael J Mansfield
- Department of Biology, University of Waterloo, 200 University Ave. West, Waterloo, Ontario N2L 3G1, Canada
| | - Jeremy B Adams
- Department of Biology, University of Waterloo, 200 University Ave. West, Waterloo, Ontario N2L 3G1, Canada
| | - Andrew C Doxey
- Department of Biology, University of Waterloo, 200 University Ave. West, Waterloo, Ontario N2L 3G1, Canada.
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Govender VS, Ramsugit S, Pillay M. Mycobacterium tuberculosis adhesins: potential biomarkers as anti-tuberculosis therapeutic and diagnostic targets. Microbiology (Reading) 2014; 160:1821-1831. [DOI: 10.1099/mic.0.082206-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Adhesion to host cells is a precursor to host colonization and evasion of the host immune response. Conversely, it triggers the induction of the immune response, a process vital to the host’s defence against infection. Adhesins are microbial cell surface molecules or structures that mediate the attachment of the microbe to host cells and thus the host–pathogen interaction. They also play a crucial role in bacterial aggregation and biofilm formation. In this review, we discuss the role of adhesins in the pathogenesis of the aetiological agent of tuberculosis, Mycobacterium tuberculosis. We also provide insight into the structure and characteristics of some of the characterized and putative M. tuberculosis adhesins. Finally, we examine the potential of adhesins as targets for the development of tuberculosis control strategies.
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Affiliation(s)
- Viveshree S. Govender
- Medical Microbiology and Infection Control, University of KwaZulu-Natal, Durban, South Africa
| | - Saiyur Ramsugit
- Medical Microbiology and Infection Control, University of KwaZulu-Natal, Durban, South Africa
| | - Manormoney Pillay
- Medical Microbiology and Infection Control, University of KwaZulu-Natal, Durban, South Africa
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Afzal S, Idrees M, Hussain M. De Novo modeling of Envelope 2 protein of HCV isolated from Pakistani patient and epitopes prediction for vaccine development. J Transl Med 2014; 12:115. [PMID: 24885362 PMCID: PMC4024208 DOI: 10.1186/1479-5876-12-115] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Accepted: 03/26/2014] [Indexed: 01/27/2023] Open
Abstract
Hepatitis C virus (HCV) is a universal health issue and a significant risk factor leading to hepatocellular carcinoma. HCV has infected approximately 170 million individuals worldwide. It is a member of Flaviviridae with positive sense RNA genome. In the absence of any effective vaccine against HCV, pegylated interferon with ribavirin is the standard of treatment against HCV infection. In this study, sequence and structural analysis of envelope 2 (E2) protein was performed which was isolated from patients of HCV genotype 3a in Pakistan. Then, epitopes were predicted which were specific for both B-cells and T-cells. Later, conservancy of epitopes was checked with the HCV 3a and 1a sequences from different countries. A total of 6 conserved epitopes were found from extra-membranous regions of E2 protein. Presence of conserved epitopes in E2 protein generates the possibility that these epitopes can be used to elicit the immune response against HCV.
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Affiliation(s)
| | - Muhammad Idrees
- Division of Molecular Virology, National Centre of Excellence in Molecular Biology, University of the Punjab, 87-West Canal Bank Road Thokar Niaz Baig, Lahore 53700, Pakistan.
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Winther M, Walmod PS. Neural cell adhesion molecules belonging to the family of leucine-rich repeat proteins. ADVANCES IN NEUROBIOLOGY 2014; 8:315-95. [PMID: 25300143 DOI: 10.1007/978-1-4614-8090-7_14] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Leucine-rich repeats (LRRs) are motifs that form protein-ligand interaction domains. There are approximately 140 human genes encoding proteins with extracellular LRRs. These encode cell adhesion molecules (CAMs), proteoglycans, G-protein-coupled receptors, and other types of receptors. Here we give a brief description of 36 proteins with extracellular LRRs that all can be characterized as CAMs or putative CAMs expressed in the nervous system. The proteins are involved in multiple biological processes in the nervous system including the proliferation and survival of cells, neuritogenesis, axon guidance, fasciculation, myelination, and the formation and maintenance of synapses. Moreover, the proteins are functionally implicated in multiple diseases including cancer, hearing impairment, glaucoma, Alzheimer's disease, multiple sclerosis, Parkinson's disease, autism spectrum disorders, schizophrenia, and obsessive-compulsive disorders. Thus, LRR-containing CAMs constitute a large group of proteins of pivotal importance for the development, maintenance, and regeneration of the nervous system.
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Rana A, Rub A, Akhter Y. Proteome-scale identification of outer membrane proteins in Mycobacterium avium subspecies paratuberculosis using a structure based combined hierarchical approach. ACTA ACUST UNITED AC 2014; 10:2329-37. [DOI: 10.1039/c4mb00234b] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The overall strategy used for the proteome-wide comprehensive computational investigation to identify outer membrane proteins fromMycobacterium aviumsubsp.paratuberculosis.
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Affiliation(s)
- Aarti Rana
- School of Life Sciences
- Central University of Himachal Pradesh
- District-Kangra, India
| | - Abdur Rub
- Infection and Immunity Lab
- Department of Biotechnology
- Jamia Millia Islamia (A Central University)
- New Delhi, India-110025
| | - Yusuf Akhter
- School of Life Sciences
- Central University of Himachal Pradesh
- District-Kangra, India
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Provenzano JC, Siqueira JF, Rôças IN, Domingues RR, Paes Leme AF, Silva MRS. Metaproteome analysis of endodontic infections in association with different clinical conditions. PLoS One 2013; 8:e76108. [PMID: 24143178 PMCID: PMC3797121 DOI: 10.1371/journal.pone.0076108] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Accepted: 08/21/2013] [Indexed: 12/12/2022] Open
Abstract
Analysis of the metaproteome of microbial communities is important to provide an insight of community physiology and pathogenicity. This study evaluated the metaproteome of endodontic infections associated with acute apical abscesses and asymptomatic apical periodontitis lesions. Proteins persisting or expressed after root canal treatment were also evaluated. Finally, human proteins associated with these infections were identified. Samples were taken from root canals of teeth with asymptomatic apical periodontitis before and after chemomechanical treatment using either NaOCl or chlorhexidine as the irrigant. Samples from abscesses were taken by aspiration of the purulent exudate. Clinical samples were processed for analysis of the exoproteome by using two complementary mass spectrometry platforms: nanoflow liquid chromatography coupled with linear ion trap quadrupole Velos Orbitrap and liquid chromatography-quadrupole time-of-flight. A total of 308 proteins of microbial origin were identified. The number of proteins in abscesses was higher than in asymptomatic cases. In canals irrigated with chlorhexidine, the number of identified proteins decreased substantially, while in the NaOCl group the number of proteins increased. The large majority of microbial proteins found in endodontic samples were related to metabolic and housekeeping processes, including protein synthesis, energy metabolism and DNA processes. Moreover, several other proteins related to pathogenicity and resistance/survival were found, including proteins involved with adhesion, biofilm formation and antibiotic resistance, stress proteins, exotoxins, invasins, proteases and endopeptidases (mostly in abscesses), and an archaeal protein linked to methane production. The majority of human proteins detected were related to cellular processes and metabolism, as well as immune defense. Interrogation of the metaproteome of endodontic microbial communities provides information on the physiology and pathogenicity of the community at the time of sampling. There is a growing need for expanded and more curated protein databases that permit more accurate identifications of proteins in metaproteomic studies.
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Affiliation(s)
- José Claudio Provenzano
- Department of Biochemistry, Chemistry Institute, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil ; Department of Endodontics, Faculty of Dentistry, Estácio de Sá University, Rio de Janeiro, RJ, Brazil
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Shaffer TL, Balder R, Buskirk SW, Hogan RJ, Lafontaine ER. Use of the Chinchilla model to evaluate the vaccinogenic potential of the Moraxella catarrhalis filamentous hemagglutinin-like proteins MhaB1 and MhaB2. PLoS One 2013; 8:e67881. [PMID: 23844117 PMCID: PMC3699455 DOI: 10.1371/journal.pone.0067881] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Accepted: 05/23/2013] [Indexed: 11/19/2022] Open
Abstract
Moraxella catarrhalis causes significant health problems, including 15–20% of otitis media cases in children and ∼10% of respiratory infections in adults with chronic obstructive pulmonary disease. The lack of an efficacious vaccine, the rapid emergence of antibiotic resistance in clinical isolates, and high carriage rates reported in children are cause for concern. In addition, the effectiveness of conjugate vaccines at reducing the incidence of otitis media caused by Streptococcus pneumoniae and nontypeable Haemophilus influenzae suggest that M. catarrhalis infections may become even more prevalent. Hence, M. catarrhalis is an important and emerging cause of infectious disease for which the development of a vaccine is highly desirable. Studying the pathogenesis of M. catarrhalis and the testing of vaccine candidates have both been hindered by the lack of an animal model that mimics human colonization and infection. To address this, we intranasally infected chinchilla with M. catarrhalis to investigate colonization and examine the efficacy of a protein-based vaccine. The data reveal that infected chinchillas produce antibodies against antigens known to be major targets of the immune response in humans, thus establishing immune parallels between chinchillas and humans during M. catarrhalis infection. Our data also demonstrate that a mutant lacking expression of the adherence proteins MhaB1 and MhaB2 is impaired in its ability to colonize the chinchilla nasopharynx, and that immunization with a polypeptide shared by MhaB1 and MhaB2 elicits antibodies interfering with colonization. These findings underscore the importance of adherence proteins in colonization and emphasize the relevance of the chinchilla model to study M. catarrhalis–host interactions.
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Affiliation(s)
- Teresa L. Shaffer
- Department of Microbiology, University of Georgia, Athens, Georgia, United States of America
| | - Rachel Balder
- Department of Infectious Diseases, University of Georgia, Athens, Georgia, United States of America
| | - Sean W. Buskirk
- Department of Infectious Diseases, University of Georgia, Athens, Georgia, United States of America
| | - Robert J. Hogan
- Department of Infectious Diseases, University of Georgia, Athens, Georgia, United States of America
- Department of Veterinary Biosciences and Diagnostic Imaging, University of Georgia, Athens, Georgia, United States of America
| | - Eric R. Lafontaine
- Department of Infectious Diseases, University of Georgia, Athens, Georgia, United States of America
- * E-mail:
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Bodelón G, Palomino C, Fernández LÁ. Immunoglobulin domains inEscherichia coliand other enterobacteria: from pathogenesis to applications in antibody technologies. FEMS Microbiol Rev 2013; 37:204-50. [DOI: 10.1111/j.1574-6976.2012.00347.x] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 06/07/2012] [Accepted: 06/14/2012] [Indexed: 11/28/2022] Open
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Lima SS, Ching ATC, Fávaro RD, Da Silva JB, Oliveira MLS, Carvalho E, Abreu PAE, Vasconcellos SA, Ho PL. Adhesin activity of Leptospira interrogans lipoprotein identified by in vivo and in vitro shotgun phage display. Biochem Biophys Res Commun 2013; 431:342-7. [PMID: 23291183 DOI: 10.1016/j.bbrc.2012.12.095] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Accepted: 12/22/2012] [Indexed: 11/19/2022]
Abstract
Leptospira interrogans causes leptospirosis, one of the most common zoonotic diseases in the world. This pathogenic spirochete is able to bind to extracellular matrix, to express virulent factors and to cause host death. Until now, there is no effective human vaccine for the disease. Shotgun phage display genomic libraries of L. interrogans were constructed and used for in vivo biopanning in hamsters and screened for ligands able to bind to LLC-PK1 epithelial cells. In both panning procedures, clones coding for the putative lipoprotein LIC12976 were identified and, in order to confirm its adhesin activity, a recombinant protein was produced in Escherichia coli and showed to interact with A31 fibroblasts, LLC-PK1 and Vero epithelial cells in vitro. Moreover, rLIC12976 was shown to bind to laminin, indicating an adhesin function. This protein was also detected in extracts of L. interrogans from different serovars and it was found to be conserved among pathogenic leptospires. Further, the protein was tested as vaccine candidate and immunization of hamsters with LIC12976 did not confer protection against a lethal challenge with the homologous L. interrogans serovar Copenhageni. Nevertheless, LIC12976 seems to act as an adhesin, and may be important for the host-pathogen interaction, so that its study can contribute to the understanding of the virulence mechanisms in pathogenic leptospires.
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Sharma A, Arya DK, Sagar V, Bergmann R, Chhatwal GS, Johri AK. Identification of potential universal vaccine candidates against group A Streptococcus by using high throughput in silico and proteomics approach. J Proteome Res 2012. [PMID: 23181284 DOI: 10.1021/pr3005265] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Streptococcus pyogenes or group A Streptococcus (GAS) causes ~700 million human infections each year, resulting in over 500,000 deaths. The development of a commercial GAS vaccine is hampered due to high strain and serotype diversity in different geographical regions, and the generation of cross-reactive antibodies that may induce autoimmune disease. There is an urgent need to search for alternative vaccine candidates. High throughput multigenome data mining coupled with proteomics seems to be a promising approach to identify the universal vaccine candidates. In the present study, in silico analysis led to prediction of 147 proteins as universal vaccine candidates. Distribution pattern of these predicted candidates was explored in nonsequenced Indian GAS strains (n = 20) by using DNA array hybridization validating in silico analysis. High throughput analyses of surface proteins using 1D-SDS-PAGE coupled with ESI-LC-MS/MS was applied on highly (M49) and less (M1) invasive GAS strains of Indian origin. Comparative proteomics analysis revealed that highly invasive GAS M49 had metabolically more active membrane associated protein machinery than less invasive M1. Further, by overlapping proteomics data with in silico predicted vaccine candidate genes, 52 proteins were identified as probable universal vaccine candidates, which were expressed in these GAS serotypes. These proteins can further be investigated as universal vaccine candidates against GAS. Moreover, this robust approach may serve as a model that can be applied to identify the universal vaccine candidates in case of other pathogenic bacteria with high strain and genetic diversity.
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Affiliation(s)
- Abhinay Sharma
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
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Kochut A, Dersch P. Bacterial invasion factors: tools for crossing biological barriers and drug delivery? Eur J Pharm Biopharm 2012. [PMID: 23207324 DOI: 10.1016/j.ejpb.2012.11.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The oral route is the preferential route of drug delivery in humans. However, effective delivery through the gastrointestinal tract is often hampered by the low permeability of the intestinal epithelium. One possibility to overcome this problem is the encapsulation of drugs inside nanoparticulate systems, containing targeting moieties with cell invasive properties. The bioinvasive features of the delivery system could be provided by the attachment of bacterial invasion factors, which promote efficient uptake into host cells and mediate rapid transcytosis of the pathogen through the intestinal epithelium. This review gives an overview of bacterial invasion systems. The molecular structure and function of suitable bacterial invasins, their relative values as targeting agents and possible pitfalls of their use are described. The potential of bioinvasive drug delivery systems is mainly presented on the basis of the well-characterized Yersinia invasin protein, which enters M cells to gain access to subepithelial layers of the gastrointestinal tract, but alternative approaches and future prospects for oral drug delivery are also discussed.
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Affiliation(s)
- Annika Kochut
- Department of Molecular Infection Biology, Helmholtz Center for Infection Research, Braunschweig, Germany
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Niemann HH, Gherardi E, Bleymüller WM, Heinz DW. Engineered variants of InlB with an additional leucine-rich repeat discriminate between physiologically relevant and packing contacts in crystal structures of the InlB:MET complex. Protein Sci 2012; 21:1528-39. [PMID: 22887347 PMCID: PMC3526994 DOI: 10.1002/pro.2142] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Revised: 08/01/2012] [Accepted: 08/06/2012] [Indexed: 11/07/2022]
Abstract
The physiological relevance of contacts in crystal lattices often remains elusive. This was also the case for the complex between the invasion protein internalin B (InlB) from Listeria monocytogenes and its host cell receptor, the human receptor tyrosine kinase (RTK) MET. InlB is a MET agonist and induces bacterial host cell invasion. Activation of RTKs generally involves ligand-induced dimerization of the receptor ectodomain. The two currently available crystal structures of the InlB:MET complex show the same arrangement of InlB and MET in a 1:1 complex, but different dimeric 2:2 assemblies. Only one of these 2:2 assemblies is predicted to be stable by a computational procedure. This assembly is mainly stabilized by a contact between the Cap domain of InlB from one and the Sema domain of MET from another 1:1 complex. Here, we probe the physiological relevance of this interaction. We generated variants of the leucine-rich repeat (LRR) protein InlB by inserting an additional repeat between the first and the second LRR. This should allow formation of the 1:1 complex but disrupt the potential 2:2 complex involving the Cap-Sema contact due to steric distortions. A crystal structure of one of the engineered proteins showed that it folded properly. Binding affinity to MET was comparable to that of wild-type InlB. The InlB variant induced MET phosphorylation and cell scatter like wild-type InlB. These results suggest that the Cap-Sema interaction is not physiologically relevant and support the previously proposed assembly, in which a 2:2 InlB:MET complex is built around a ligand dimer.
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Affiliation(s)
- Hartmut H Niemann
- Department of Chemistry, Bielefeld University, 33501 Bielefeld, Germany.
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Acinetobacter calcoaceticus-baumannii complex strains induce caspase-dependent and caspase-independent death of human epithelial cells. Curr Microbiol 2012; 65:319-29. [PMID: 22684803 PMCID: PMC3401494 DOI: 10.1007/s00284-012-0159-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Accepted: 05/15/2012] [Indexed: 12/25/2022]
Abstract
We investigated interactions of human isolates of Acinetobacter calcoaceticus–baumannii complex strains with epithelial cells. The results showed that bacterial contact with the cells as well as adhesion and invasion were required for induction of cytotoxicity. The infected cells revealed hallmarks of apoptosis characterized by cell shrinking, condensed chromatin, and internucleosomal fragmentation of nuclear DNA. The highest apoptotic index was observed for 4 of 10 A.calcoaceticus and 4 of 7 A. baumannii strains. Moreover, we observed oncotic changes: cellular swelling and blebbing, noncondensed chromatin, and the absence of DNA fragmentation. The highest oncotic index was observed in cells infected with 6 A.calcoaceticus isolates. Cell-contact cytotoxicity and cell death were not inhibited by the pan-caspase inhibitor z-VAD-fmk. Induction of oncosis was correlated with increased invasive ability of the strains. We demonstrated that the mitochondria of infected cells undergo structural and functional alterations which can lead to cell death. Infected apoptotic and oncotic cells exhibited loss of mitochondrial transmembrane potential (ΔΨm). Bacterial infection caused generation of nitric oxide and reactive oxygen species. This study indicated that Acinetobacter spp. induced strain-dependent distinct types of epithelial cell death that may contribute to the pathogenesis of bacterial infection.
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Rubinchik S, Seddon A, Karlyshev AV. Molecular mechanisms and biological role of Campylobacter jejuni attachment to host cells. Eur J Microbiol Immunol (Bp) 2012; 2:32-40. [PMID: 24611119 DOI: 10.1556/eujmi.2.2012.1.6] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Accepted: 01/04/2012] [Indexed: 01/13/2023] Open
Abstract
Adhesion to host cells is an important step in pathogenesis of Campylobacter jejuni, which is the most prevalent bacterial cause of human gastroenteritis worldwide. In contrast to other bacteria such as E. coli and Salmonella, adherence of C. jejuni is not mediated by fimbria or pili. A number of C. jejuni adhesion-related factors have been described. However, the results obtained by different researchers in different laboratories are often contradictory and inconclusive, with only some of the factors described being confirmed as true adhesins. In this review, we present the current state of studies on the mechanisms of attachment of C. jejuni to host cells.
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Affiliation(s)
- S Rubinchik
- School of Life Sciences, Faculty of Science, Engineering and Computing, Kingston University Penrhyn Road, Kingston-upon Thames, KT1 2EE UK
| | - A Seddon
- School of Life Sciences, Faculty of Science, Engineering and Computing, Kingston University Penrhyn Road, Kingston-upon Thames, KT1 2EE UK
| | - A V Karlyshev
- School of Life Sciences, Faculty of Science, Engineering and Computing, Kingston University Penrhyn Road, Kingston-upon Thames, KT1 2EE UK
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Sabbadini PS, Assis MC, Trost E, Gomes DLR, Moreira LO, Dos Santos CS, Pereira GA, Nagao PE, Azevedo VADC, Hirata Júnior R, Dos Santos ALS, Tauch A, Mattos-Guaraldi AL. Corynebacterium diphtheriae 67-72p hemagglutinin, characterized as the protein DIP0733, contributes to invasion and induction of apoptosis in HEp-2 cells. Microb Pathog 2012; 52:165-76. [PMID: 22239957 DOI: 10.1016/j.micpath.2011.12.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Revised: 11/29/2011] [Accepted: 12/05/2011] [Indexed: 11/25/2022]
Abstract
Although Corynebacterium diphtheriae has been classically described as an exclusively extracellular pathogen, there is growing evidence that it may be internalized by epithelial cells. The aim of the present report was to investigate the nature and involvement of the surface-exposed non-fimbrial 67-72 kDa proteins (67-72p), previously characterized as adhesin/hemagglutinin, in C. diphtheriae internalization by HEp-2 cells. Transmission electron microscopy and bacterial internalization inhibition assays indicated the role of 67-72p as invasin for strains of varied sources. Cytoskeletal changes with accumulation of polymerized actin in HEp-2 cells beneath adherent 67-72p-adsorbed microspheres were observed by the Fluorescent actin staining test. Trypan blue staining method and Methylthiazole tetrazolium reduction assay showed a significant decrease in viability of HEp-2 cells treated with 67-72p. Morphological changes in HEp-2 cells observed after treatment with 67-72p included vacuolization, nuclear fragmentation and the formation of apoptotic bodies. Flow cytometry revealed an apoptotic volume decrease in HEp-2 cells treated with 67-72p. Moreover, a double-staining assay using Propidium Iodide/Annexin V gave information about the numbers of vital vs. early apoptotic cells and late apoptotic or secondary necrotic cells. The comparative analysis of MALDI-TOF MS experiments with the probes provided for 67-72p CDC-E8392 with an in silico proteome deduced from the complete genome sequence of C. diphtheriae identified with significant scores 67-72p as the protein DIP0733. In conclusion, DIP0733 (67-72p) may be directly implicated in bacterial invasion and apoptosis of epithelial cells in the early stages of diphtheria and C. diphtheriae invasive infection.
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Adhesive polypeptides of Staphylococcus aureus identified using a novel secretion library technique in Escherichia coli. BMC Microbiol 2011; 11:117. [PMID: 21615970 PMCID: PMC3127751 DOI: 10.1186/1471-2180-11-117] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2011] [Accepted: 05/27/2011] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Bacterial adhesive proteins, called adhesins, are frequently the decisive factor in initiation of a bacterial infection. Characterization of such molecules is crucial for the understanding of bacterial pathogenesis, design of vaccines and development of antibacterial drugs. Because adhesins are frequently difficult to express, their characterization has often been hampered. Alternative expression methods developed for the analysis of adhesins, e.g. surface display techniques, suffer from various drawbacks and reports on high-level extracellular secretion of heterologous proteins in Gram-negative bacteria are scarce. These expression techniques are currently a field of active research. The purpose of the current study was to construct a convenient, new technique for identification of unknown bacterial adhesive polypeptides directly from the growth medium of the Escherichia coli host and to identify novel proteinaceous adhesins of the model organism Staphylococcus aureus. RESULTS Randomly fragmented chromosomal DNA of S. aureus was cloned into a unique restriction site of our expression vector, which facilitates secretion of foreign FLAG-tagged polypeptides into the growth medium of E. coli ΔfliCΔfliD, to generate a library of 1663 clones expressing FLAG-tagged polypeptides. Sequence and bioinformatics analyses showed that in our example, the library covered approximately 32% of the S. aureus proteome. Polypeptides from the growth medium of the library clones were screened for binding to a selection of S. aureus target molecules and adhesive fragments of known staphylococcal adhesins (e.g coagulase and fibronectin-binding protein A) as well as polypeptides of novel function (e.g. a universal stress protein and phosphoribosylamino-imidazole carboxylase ATPase subunit) were detected. The results were further validated using purified His-tagged recombinant proteins of the corresponding fragments in enzyme-linked immunoassay and surface plasmon resonance analysis. CONCLUSIONS A new technique for identification of unknown bacterial adhesive polypeptides was constructed. Application of the method on S. aureus allowed us to identify three known adhesins and in addition, five new polypeptides binding to human plasma and extracellular matrix proteins. The method, here used on S. aureus, is convenient due to the use of soluble proteins from the growth medium and can in principle be applied to any bacterial species of interest.
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