1
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Tam YL, Cameron S, Preston A, Cowley L. GWarrange: a pre- and post- genome-wide association studies pipeline for detecting phenotype-associated genome rearrangement events. Microb Genom 2024; 10:001268. [PMID: 38980151 PMCID: PMC11316554 DOI: 10.1099/mgen.0.001268] [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: 01/18/2024] [Accepted: 06/17/2024] [Indexed: 07/10/2024] Open
Abstract
The use of k-mers to capture genetic variation in bacterial genome-wide association studies (bGWAS) has demonstrated its effectiveness in overcoming the plasticity of bacterial genomes by providing a comprehensive array of genetic variants in a genome set that is not confined to a single reference genome. However, little attempt has been made to interpret k-mers in the context of genome rearrangements, partly due to challenges in the exhaustive and high-throughput identification of genome structure and individual rearrangement events. Here, we present GWarrange, a pre- and post-bGWAS processing methodology that leverages the unique properties of k-mers to facilitate bGWAS for genome rearrangements. Repeat sequences are common instigators of genome rearrangements through intragenomic homologous recombination, and they are commonly found at rearrangement boundaries. Using whole-genome sequences, repeat sequences are replaced by short placeholder sequences, allowing the regions flanking repeats to be incorporated into relatively short k-mers. Then, locations of flanking regions in significant k-mers are mapped back to complete genome sequences to visualise genome rearrangements. Four case studies based on two bacterial species (Bordetella pertussis and Enterococcus faecium) and a simulated genome set are presented to demonstrate the ability to identify phenotype-associated rearrangements. GWarrange is available at https://github.com/DorothyTamYiLing/GWarrange.
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Affiliation(s)
- Yi Ling Tam
- The Milner Centre for Evolution and Department of Life Sciences, University of Bath, Claverton Down, Bath, BA2 7AY, UK
| | - Sarah Cameron
- The Milner Centre for Evolution and Department of Life Sciences, University of Bath, Claverton Down, Bath, BA2 7AY, UK
| | - Andrew Preston
- The Milner Centre for Evolution and Department of Life Sciences, University of Bath, Claverton Down, Bath, BA2 7AY, UK
| | - Lauren Cowley
- The Milner Centre for Evolution and Department of Life Sciences, University of Bath, Claverton Down, Bath, BA2 7AY, UK
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2
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Costa TRD, Patkowski JB, Macé K, Christie PJ, Waksman G. Structural and functional diversity of type IV secretion systems. Nat Rev Microbiol 2024; 22:170-185. [PMID: 37814112 PMCID: PMC11290344 DOI: 10.1038/s41579-023-00974-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/13/2023] [Indexed: 10/11/2023]
Abstract
Considerable progress has been made in recent years in the structural and molecular biology of type IV secretion systems in Gram-negative bacteria. The latest advances have substantially improved our understanding of the mechanisms underlying the recruitment and delivery of DNA and protein substrates to the extracellular environment or target cells. In this Review, we aim to summarize these exciting structural and molecular biology findings and to discuss their functional implications for substrate recognition, recruitment and translocation, as well as the biogenesis of extracellular pili. We also describe adaptations necessary for deploying a breadth of processes, such as bacterial survival, host-pathogen interactions and biotic and abiotic adhesion. We highlight the functional and structural diversity that allows this extremely versatile secretion superfamily to function under different environmental conditions and in different bacterial species. Additionally, we emphasize the importance of further understanding the mechanism of type IV secretion, which will support us in combating antimicrobial resistance and treating type IV secretion system-related infections.
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Affiliation(s)
- Tiago R D Costa
- Centre for Bacterial Resistance Biology, Department of Life Sciences, Imperial College, London, UK.
| | - Jonasz B Patkowski
- Centre for Bacterial Resistance Biology, Department of Life Sciences, Imperial College, London, UK
| | - Kévin Macé
- Institute of Structural and Molecular Biology, Birkbeck and UCL, London, UK
- Institut de Génétique et Développement de Rennes (IGDR), Université de Rennes and CNRS, Rennes, France
| | - Peter J Christie
- Department of Microbiology and Molecular Genetics, McGovern Medical School at UTHealth, Houston, TX, USA.
| | - Gabriel Waksman
- Institute of Structural and Molecular Biology, Birkbeck and UCL, London, UK.
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3
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Zhernakova DV, Wang D, Liu L, Andreu-Sánchez S, Zhang Y, Ruiz-Moreno AJ, Peng H, Plomp N, Del Castillo-Izquierdo Á, Gacesa R, Lopera-Maya EA, Temba GS, Kullaya VI, van Leeuwen SS, Xavier RJ, de Mast Q, Joosten LAB, Riksen NP, Rutten JHW, Netea MG, Sanna S, Wijmenga C, Weersma RK, Zhernakova A, Harmsen HJM, Fu J. Host genetic regulation of human gut microbial structural variation. Nature 2024; 625:813-821. [PMID: 38172637 PMCID: PMC10808065 DOI: 10.1038/s41586-023-06893-w] [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: 12/22/2022] [Accepted: 11/23/2023] [Indexed: 01/05/2024]
Abstract
Although the impact of host genetics on gut microbial diversity and the abundance of specific taxa is well established1-6, little is known about how host genetics regulates the genetic diversity of gut microorganisms. Here we conducted a meta-analysis of associations between human genetic variation and gut microbial structural variation in 9,015 individuals from four Dutch cohorts. Strikingly, the presence rate of a structural variation segment in Faecalibacterium prausnitzii that harbours an N-acetylgalactosamine (GalNAc) utilization gene cluster is higher in individuals who secrete the type A oligosaccharide antigen terminating in GalNAc, a feature that is jointly determined by human ABO and FUT2 genotypes, and we could replicate this association in a Tanzanian cohort. In vitro experiments demonstrated that GalNAc can be used as the sole carbohydrate source for F. prausnitzii strains that carry the GalNAc-metabolizing pathway. Further in silico and in vitro studies demonstrated that other ABO-associated species can also utilize GalNAc, particularly Collinsella aerofaciens. The GalNAc utilization genes are also associated with the host's cardiometabolic health, particularly in individuals with mucosal A-antigen. Together, the findings of our study demonstrate that genetic associations across the human genome and bacterial metagenome can provide functional insights into the reciprocal host-microbiome relationship.
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Affiliation(s)
- Daria V Zhernakova
- University of Groningen, University Medical Center Groningen, Department of Genetics, Groningen, The Netherlands
| | - Daoming Wang
- University of Groningen, University Medical Center Groningen, Department of Genetics, Groningen, The Netherlands
- University of Groningen, University Medical Center Groningen, Department of Pediatrics, Groningen, The Netherlands
| | - Lei Liu
- University of Groningen, University Medical Center Groningen, Department of Medical Microbiology and Infection Prevention, Groningen, The Netherlands
| | - Sergio Andreu-Sánchez
- University of Groningen, University Medical Center Groningen, Department of Genetics, Groningen, The Netherlands
- University of Groningen, University Medical Center Groningen, Department of Pediatrics, Groningen, The Netherlands
| | - Yue Zhang
- University of Groningen, University Medical Center Groningen, Department of Genetics, Groningen, The Netherlands
- University of Groningen, University Medical Center Groningen, Department of Pediatrics, Groningen, The Netherlands
| | - Angel J Ruiz-Moreno
- University of Groningen, University Medical Center Groningen, Department of Genetics, Groningen, The Netherlands
- University of Groningen, University Medical Center Groningen, Department of Pediatrics, Groningen, The Netherlands
| | - Haoran Peng
- University of Groningen, University Medical Center Groningen, Department of Genetics, Groningen, The Netherlands
| | - Niels Plomp
- University of Groningen, University Medical Center Groningen, Department of Medical Microbiology and Infection Prevention, Groningen, The Netherlands
- University of Groningen, University Medical Center Groningen, Department of Gastroenterology and Hepatology, Groningen, The Netherlands
| | - Ángela Del Castillo-Izquierdo
- University of Groningen, University Medical Center Groningen, Department of Genetics, Groningen, The Netherlands
- University of Groningen, University Medical Center Groningen, Department of Medical Microbiology and Infection Prevention, Groningen, The Netherlands
| | - Ranko Gacesa
- University of Groningen, University Medical Center Groningen, Department of Genetics, Groningen, The Netherlands
- University of Groningen, University Medical Center Groningen, Department of Gastroenterology and Hepatology, Groningen, The Netherlands
| | - Esteban A Lopera-Maya
- University of Groningen, University Medical Center Groningen, Department of Genetics, Groningen, The Netherlands
| | - Godfrey S Temba
- Department of Internal Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
- Department of Medical Biochemistry and Molecular Biology, Kilimanjaro Christian Medical University College, Moshi, Tanzania
- Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Vesla I Kullaya
- Department of Medical Biochemistry and Molecular Biology, Kilimanjaro Christian Medical University College, Moshi, Tanzania
- Kilimanjaro Clinical Research Institute, Kilimanjaro Christian Medical Center, Moshi, Tanzania
| | - Sander S van Leeuwen
- University of Groningen, University Medical Center Groningen, Department of Laboratory Medicine, Groningen, The Netherlands
| | - Ramnik J Xavier
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Center for Computational and Integrative Biology, Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA
| | - Quirijn de Mast
- Department of Internal Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
- Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Leo A B Joosten
- Department of Internal Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
- Department of Medical Genetics, Iuliu Haţieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania
| | - Niels P Riksen
- Department of Internal Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Joost H W Rutten
- Department of Internal Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Mihai G Netea
- Department of Internal Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
- Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
- Department of Immunology and Metabolism, Life and Medical Sciences Institute, University of Bonn, Bonn, Germany
- Human Genomics Laboratory, Craiova University of Medicine and Pharmacy, Craiova, Romania
| | - Serena Sanna
- University of Groningen, University Medical Center Groningen, Department of Genetics, Groningen, The Netherlands
- Institute for Genetic and Biomedical Research, National Research Council, Cagliari, Italy
| | - Cisca Wijmenga
- University of Groningen, University Medical Center Groningen, Department of Genetics, Groningen, The Netherlands
| | - Rinse K Weersma
- University of Groningen, University Medical Center Groningen, Department of Gastroenterology and Hepatology, Groningen, The Netherlands
| | - Alexandra Zhernakova
- University of Groningen, University Medical Center Groningen, Department of Genetics, Groningen, The Netherlands
| | - Hermie J M Harmsen
- University of Groningen, University Medical Center Groningen, Department of Medical Microbiology and Infection Prevention, Groningen, The Netherlands.
| | - Jingyuan Fu
- University of Groningen, University Medical Center Groningen, Department of Genetics, Groningen, The Netherlands.
- University of Groningen, University Medical Center Groningen, Department of Pediatrics, Groningen, The Netherlands.
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4
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Perkins ML, Gandara L, Crocker J. A synthetic synthesis to explore animal evolution and development. Philos Trans R Soc Lond B Biol Sci 2022; 377:20200517. [PMID: 35634925 PMCID: PMC9149795 DOI: 10.1098/rstb.2020.0517] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Identifying the general principles by which genotypes are converted into phenotypes remains a challenge in the post-genomic era. We still lack a predictive understanding of how genes shape interactions among cells and tissues in response to signalling and environmental cues, and hence how regulatory networks generate the phenotypic variation required for adaptive evolution. Here, we discuss how techniques borrowed from synthetic biology may facilitate a systematic exploration of evolvability across biological scales. Synthetic approaches permit controlled manipulation of both endogenous and fully engineered systems, providing a flexible platform for investigating causal mechanisms in vivo. Combining synthetic approaches with multi-level phenotyping (phenomics) will supply a detailed, quantitative characterization of how internal and external stimuli shape the morphology and behaviour of living organisms. We advocate integrating high-throughput experimental data with mathematical and computational techniques from a variety of disciplines in order to pursue a comprehensive theory of evolution. This article is part of the theme issue ‘Genetic basis of adaptation and speciation: from loci to causative mutations’.
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Affiliation(s)
- Mindy Liu Perkins
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Lautaro Gandara
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Justin Crocker
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
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5
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CRISPR-Cas-mediated gene editing in lactic acid bacteria. Mol Biol Rep 2020; 47:8133-8144. [PMID: 32926267 DOI: 10.1007/s11033-020-05820-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 09/05/2020] [Indexed: 12/12/2022]
Abstract
The high efficiency, convenience and diversity of clustered regular interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) systems are driving a technological revolution in the gene editing of lactic acid bacteria (LAB). Cas-RNA cassettes have been adopted as tools to perform gene deletion, insertion and point mutation in several species of LAB. In this article, we describe the basic mechanisms of the CRISPR-Cas system, and the current gene editing methods available, focusing on the CRISPR-Cas models developed for LAB. We also compare the different types of CRISPR-Cas-based genomic manipulations classified according to the different Cas proteins and the type of recombineering, and discuss the rapidly evolving landscape of CRISPR-Cas application in LAB.
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6
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Belikova D, Jochim A, Power J, Holden MTG, Heilbronner S. "Gene accordions" cause genotypic and phenotypic heterogeneity in clonal populations of Staphylococcus aureus. Nat Commun 2020; 11:3526. [PMID: 32665571 PMCID: PMC7360770 DOI: 10.1038/s41467-020-17277-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 06/15/2020] [Indexed: 12/18/2022] Open
Abstract
Gene tandem amplifications are thought to drive bacterial evolution, but they are transient in the absence of selection, making their investigation challenging. Here, we analyze genomic sequences of Staphylococcus aureus USA300 isolates from the same geographical area to identify variations in gene copy number, which we confirm by long-read sequencing. We find several hotspots of variation, including the csa1 cluster encoding lipoproteins known to be immunogenic. We also show that the csa1 locus expands and contracts during bacterial growth in vitro and during systemic infection of mice, and recombination creates rapid heterogeneity in initially clonal cultures. Furthermore, csa1 copy number variants differ in their immunostimulatory capacity, revealing a mechanism by which gene copy number variation can modulate the host immune response. Gene tandem amplifications can drive bacterial evolution. Here, Belikova et al. identify copy number variations of lipoprotein-encoding genes in Staphylococcus aureus clinical isolates, and show that the loci expand and contract during bacterial growth in vitro and in mice, leading to changes in immunostimulatory capacity.
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Affiliation(s)
- Darya Belikova
- Interfaculty Institute of Microbiology and Infection Medicine, Department of Infection Biology, University of Tübingen, Tübingen, Germany
| | - Angelika Jochim
- Interfaculty Institute of Microbiology and Infection Medicine, Department of Infection Biology, University of Tübingen, Tübingen, Germany
| | - Jeffrey Power
- Interfaculty Institute of Microbiology and Infection Medicine, Department of Infection Biology, University of Tübingen, Tübingen, Germany
| | | | - Simon Heilbronner
- Interfaculty Institute of Microbiology and Infection Medicine, Department of Infection Biology, University of Tübingen, Tübingen, Germany. .,German Centre for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany. .,(DFG) Cluster of Excellence EXC 2124 Controlling Microbes to Fight Infections, Tübingen, Germany.
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7
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Cabañas N, Becerra A, Romero D, Govezensky T, Espinosa-Aguirre JJ, Camacho-Carranza R. Repetitive DNA profile of the amphibian mitogenome. BMC Bioinformatics 2020; 21:197. [PMID: 32429835 PMCID: PMC7236288 DOI: 10.1186/s12859-020-3532-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 05/05/2020] [Indexed: 11/20/2022] Open
Abstract
Background Repetitive DNA elements such as direct and inverted repeat sequences are present in every genome, playing numerous biological roles. In amphibians, the functions and effects of the repeat sequences have not been extensively explored. We consider that the data of mitochondrial genomes in the NCBI database are a valuable alternative to generate a better understanding of the molecular dynamic of the repeat sequences in the amphibians. Results This work presents the development of a strategy to identify and quantify the total amount of repeat sequences with lengths from 5 to 30 base pairs in the amphibian mitogenomes. The results show differences in the abundance of repeat sequences among amphibians and bias to specific genomic regions that are not easily associated with the classical amphibian ancestry. Conclusions Derived from these analyses, we show that great variability of the repeat sequences exists among amphibians, demonstrating that the mitogenomes of these organisms are dynamic.
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Affiliation(s)
- Noel Cabañas
- Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Cd. Universitaria, 04510, Cd. Mx., Mexico
| | - Arturo Becerra
- Facultad de Ciencias, Universidad Nacional Autónoma de México, Cd. Universitaria, 04510, Cd. Mx., Mexico
| | - David Romero
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
| | - Tzipe Govezensky
- Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Cd. Universitaria, 04510, Cd. Mx., Mexico
| | - Jesús Javier Espinosa-Aguirre
- Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Cd. Universitaria, 04510, Cd. Mx., Mexico
| | - Rafael Camacho-Carranza
- Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Cd. Universitaria, 04510, Cd. Mx., Mexico. .,Facultad de Ciencias, Universidad Nacional Autónoma de México, Cd. Universitaria, 04510, Cd. Mx., Mexico.
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8
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Chen S, Chen Y, Sun F, Waterman MS, Zhang X. A new statistic for efficient detection of repetitive sequences. Bioinformatics 2019; 35:4596-4606. [PMID: 30993316 DOI: 10.1093/bioinformatics/btz262] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 03/01/2019] [Accepted: 04/10/2019] [Indexed: 11/14/2022] Open
Abstract
MOTIVATION Detecting sequences containing repetitive regions is a basic bioinformatics task with many applications. Several methods have been developed for various types of repeat detection tasks. An efficient generic method for detecting most types of repetitive sequences is still desirable. Inspired by the excellent properties and successful applications of the D2 family of statistics in comparative analyses of genomic sequences, we developed a new statistic D2R that can efficiently discriminate sequences with or without repetitive regions. RESULTS Using the statistic, we developed an algorithm of linear time and space complexity for detecting most types of repetitive sequences in multiple scenarios, including finding candidate clustered regularly interspaced short palindromic repeats regions from bacterial genomic or metagenomics sequences. Simulation and real data experiments show that the method works well on both assembled sequences and unassembled short reads. AVAILABILITY AND IMPLEMENTATION The codes are available at https://github.com/XuegongLab/D2R_codes under GPL 3.0 license. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Sijie Chen
- Department of Automation, MOE Key Laboratory of Bioinformatics, Bioinformatics Division and Center for Synthetic & Systems Biology, BNRist, Tsinghua University, Beijing 100084, China
| | - Yixin Chen
- Department of Automation, MOE Key Laboratory of Bioinformatics, Bioinformatics Division and Center for Synthetic & Systems Biology, BNRist, Tsinghua University, Beijing 100084, China
| | - Fengzhu Sun
- Quantitative and Computational Biology Program, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA.,Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai 200433, China
| | - Michael S Waterman
- Department of Automation, MOE Key Laboratory of Bioinformatics, Bioinformatics Division and Center for Synthetic & Systems Biology, BNRist, Tsinghua University, Beijing 100084, China.,Quantitative and Computational Biology Program, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA.,Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai 200433, China
| | - Xuegong Zhang
- Department of Automation, MOE Key Laboratory of Bioinformatics, Bioinformatics Division and Center for Synthetic & Systems Biology, BNRist, Tsinghua University, Beijing 100084, China.,School of Life Sciences, Tsinghua University, Beijing 100084, China
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9
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α-Difluoromethylornithine reduces gastric carcinogenesis by causing mutations in Helicobacter pylori cagY. Proc Natl Acad Sci U S A 2019; 116:5077-5085. [PMID: 30804204 DOI: 10.1073/pnas.1814497116] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Infection by Helicobacter pylori is the primary cause of gastric adenocarcinoma. The most potent H. pylori virulence factor is cytotoxin-associated gene A (CagA), which is translocated by a type 4 secretion system (T4SS) into gastric epithelial cells and activates oncogenic signaling pathways. The gene cagY encodes for a key component of the T4SS and can undergo gene rearrangements. We have shown that the cancer chemopreventive agent α-difluoromethylornithine (DFMO), known to inhibit the enzyme ornithine decarboxylase, reduces H. pylori-mediated gastric cancer incidence in Mongolian gerbils. In the present study, we questioned whether DFMO might directly affect H. pylori pathogenicity. We show that H. pylori output strains isolated from gerbils treated with DFMO exhibit reduced ability to translocate CagA in gastric epithelial cells. Further, we frequently detected genomic modifications in the middle repeat region of the cagY gene of output strains from DFMO-treated animals, which were associated with alterations in the CagY protein. Gerbils did not develop carcinoma when infected with a DFMO output strain containing rearranged cagY or the parental strain in which the wild-type cagY was replaced by cagY with DFMO-induced rearrangements. Lastly, we demonstrate that in vitro treatment of H. pylori by DFMO induces oxidative DNA damage, expression of the DNA repair enzyme MutS2, and mutations in cagY, demonstrating that DFMO directly affects genomic stability. Deletion of mutS2 abrogated the ability of DFMO to induce cagY rearrangements directly. In conclusion, DFMO-induced oxidative stress in H. pylori leads to genomic alterations and attenuates virulence.
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10
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Servetas SL, Kim A, Su H, Cha JH, Merrell DS. Comparative analysis of the Hom family of outer membrane proteins in isolates from two geographically distinct regions: The United States and South Korea. Helicobacter 2018; 23:e12461. [PMID: 29315985 DOI: 10.1111/hel.12461] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Helicobacter pylori encodes numerous outer membrane proteins (OMPs), but only a few have been characterized in depth. Deletion, duplication, and allelic variation of many of the H. pylori OMPs have been reported, which suggests that these proteins may play key roles in host adaptation. Herein, we characterize the variation observed within the Hom family of OMPs in H. pylori obtained from two geographically distinct populations. MATERIALS AND METHODS PCR genotyping of the hom genes was carried out using clinical isolates from South Korea and the United States. A combination of statistical, phylogenetic, and protein modeling analyses was conducted to further characterize the hom variants. RESULTS Variations in the closely related hom genes, homA and homB, occur in regions that are predicted to encode environmentally exposed loops. A similar phenomenon is true for homCS as compared to homCL . Conversely, little variation was observed in homD. Certain variants of the Hom family of proteins were more prominent in isolates from the Korean population as compared to isolates from the United States. CONCLUSION En masse, our data show that the homA, homB, and homC profiles vary based upon the geographic origin of the strain; however, the fourth member of the hom family, homD, is more highly conserved. Additionally, protein topology modeling showed that many of the less well-conserved regions between homA and homB and between homCS and homCL corresponded to predicted environmentally exposed loops, suggesting that the divergence of the Hom family may be due to host adaptation/pressure.
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Affiliation(s)
- Stephanie L Servetas
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Aeryun Kim
- Department of Oral Biology, Oral Science Research Center, BK21 Plus Project, Yonsei University College of Dentistry, Seoul, Korea.,Department of Applied Life Science, The Graduate School, Yonsei University, Seoul, Korea
| | - Hanfu Su
- Department of Oral Biology, Oral Science Research Center, BK21 Plus Project, Yonsei University College of Dentistry, Seoul, Korea.,Department of Applied Life Science, The Graduate School, Yonsei University, Seoul, Korea.,Microbiology and Molecular Biology Laboratory, Key Laboratory of Oral Medicine, Guangzhou Institute of Oral Disease, Stomatology Hospital of Guangzhou Medical University, Guangzhou, China
| | - Jeong-Heon Cha
- Department of Oral Biology, Oral Science Research Center, BK21 Plus Project, Yonsei University College of Dentistry, Seoul, Korea.,Department of Applied Life Science, The Graduate School, Yonsei University, Seoul, Korea.,Microbiology and Molecular Biology Laboratory, Key Laboratory of Oral Medicine, Guangzhou Institute of Oral Disease, Stomatology Hospital of Guangzhou Medical University, Guangzhou, China
| | - D Scott Merrell
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
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11
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Gámez G, Castro A, Gómez-Mejia A, Gallego M, Bedoya A, Camargo M, Hammerschmidt S. The variome of pneumococcal virulence factors and regulators. BMC Genomics 2018; 19:10. [PMID: 29298677 PMCID: PMC5753484 DOI: 10.1186/s12864-017-4376-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 12/11/2017] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND In recent years, the idea of a highly immunogenic protein-based vaccine to combat Streptococcus pneumoniae and its severe invasive infectious diseases has gained considerable interest. However, the target proteins to be included in a vaccine formulation have to accomplish several genetic and immunological characteristics, (such as conservation, distribution, immunogenicity and protective effect), in order to ensure its suitability and effectiveness. This study aimed to get comprehensive insights into the genomic organization, population distribution and genetic conservation of all pneumococcal surface-exposed proteins, genetic regulators and other virulence factors, whose important function and role in pathogenesis has been demonstrated or hypothesized. RESULTS After retrieving the complete set of DNA and protein sequences reported in the databases GenBank, KEGG, VFDB, P2CS and Uniprot for pneumococcal strains whose genomes have been fully sequenced and annotated, a comprehensive bioinformatic analysis and systematic comparison has been performed for each virulence factor, stand-alone regulator and two-component regulatory system (TCS) encoded in the pan-genome of S. pneumoniae. A total of 25 S. pneumoniae strains, representing different pneumococcal phylogenetic lineages and serotypes, were considered. A set of 92 different genes and proteins were identified, classified and studied to construct a pan-genomic variability map (variome) for S. pneumoniae. Both, pneumococcal virulence factors and regulatory genes, were well-distributed in the pneumococcal genome and exhibited a conserved feature of genome organization, where replication and transcription are co-oriented. The analysis of the population distribution for each gene and protein showed that 49 of them are part of the core genome in pneumococci, while 43 belong to the accessory-genome. Estimating the genetic variability revealed that pneumolysin, enolase and Usp45 (SP_2216 in S. p. TIGR4) are the pneumococcal virulence factors with the highest conservation, while TCS08, TCS05, and TCS02 represent the most conserved pneumococcal genetic regulators. CONCLUSIONS The results identified well-distributed and highly conserved pneumococcal virulence factors as well as regulators, representing promising candidates for a new generation of serotype-independent protein-based vaccine(s) to combat pneumococcal infections.
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Affiliation(s)
- Gustavo Gámez
- Genetics, Regeneration and Cancer Research Group (GRC), University Research Centre (SIU), Universidad de Antioquia (UdeA), Calle 70 # 52 - 21, 050010, Medellín, Colombia. .,Basic and Applied Microbiology Research Group (MICROBA), School of Microbiology, Universidad de Antioquia (UdeA), Calle 70 # 52 - 21, 050010, Medellín, Colombia. .,Department of Molecular Genetics and Infection Biology, Interfaculty Institute of Genetics and Functional Genomics, Center for Functional Genomics of Microbes, Ernst-Moritz-Arndt University of Greifswald, Felix-Hausdorff-Str. 8, D-17487, Greifswald, Germany. .,School of Microbiology, University of Antioquia, Bloque 5 - Oficina 408, Calle 70 # 52 - 21, 050010, Medellín, Colombia.
| | - Andrés Castro
- Genetics, Regeneration and Cancer Research Group (GRC), University Research Centre (SIU), Universidad de Antioquia (UdeA), Calle 70 # 52 - 21, 050010, Medellín, Colombia.,Basic and Applied Microbiology Research Group (MICROBA), School of Microbiology, Universidad de Antioquia (UdeA), Calle 70 # 52 - 21, 050010, Medellín, Colombia
| | - Alejandro Gómez-Mejia
- Genetics, Regeneration and Cancer Research Group (GRC), University Research Centre (SIU), Universidad de Antioquia (UdeA), Calle 70 # 52 - 21, 050010, Medellín, Colombia.,Department of Molecular Genetics and Infection Biology, Interfaculty Institute of Genetics and Functional Genomics, Center for Functional Genomics of Microbes, Ernst-Moritz-Arndt University of Greifswald, Felix-Hausdorff-Str. 8, D-17487, Greifswald, Germany
| | - Mauricio Gallego
- Genetics, Regeneration and Cancer Research Group (GRC), University Research Centre (SIU), Universidad de Antioquia (UdeA), Calle 70 # 52 - 21, 050010, Medellín, Colombia.,Basic and Applied Microbiology Research Group (MICROBA), School of Microbiology, Universidad de Antioquia (UdeA), Calle 70 # 52 - 21, 050010, Medellín, Colombia
| | - Alejandro Bedoya
- Genetics, Regeneration and Cancer Research Group (GRC), University Research Centre (SIU), Universidad de Antioquia (UdeA), Calle 70 # 52 - 21, 050010, Medellín, Colombia.,Basic and Applied Microbiology Research Group (MICROBA), School of Microbiology, Universidad de Antioquia (UdeA), Calle 70 # 52 - 21, 050010, Medellín, Colombia
| | - Mauricio Camargo
- Genetics, Regeneration and Cancer Research Group (GRC), University Research Centre (SIU), Universidad de Antioquia (UdeA), Calle 70 # 52 - 21, 050010, Medellín, Colombia
| | - Sven Hammerschmidt
- Department of Molecular Genetics and Infection Biology, Interfaculty Institute of Genetics and Functional Genomics, Center for Functional Genomics of Microbes, Ernst-Moritz-Arndt University of Greifswald, Felix-Hausdorff-Str. 8, D-17487, Greifswald, Germany
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12
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Molecular basis for the functions of a bacterial MutS2 in DNA repair and recombination. DNA Repair (Amst) 2017; 57:161-170. [PMID: 28800560 DOI: 10.1016/j.dnarep.2017.07.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 06/08/2017] [Accepted: 07/11/2017] [Indexed: 02/06/2023]
Abstract
Bacterial MutS2 proteins, consisting of functional domains for ATPase, DNA-binding, and nuclease activities, play roles in DNA recombination and repair. Here we observe a mechanism for generating MutS2 expression diversity in the human pathogen Helicobacter pylori, and identify a unique MutS2 domain responsible for specific DNA-binding. H. pylori strains differ in mutS2 expression due to variations in the DNA upstream sequence containing short sequence repeats. Based on Western blots, mutS2 in some strains appears to be co-translated with the upstream gene, but in other strains (e.g. UA948) such translational coupling does not occur. Accordingly, strain UA948 had phenotypes similar to its ΔmutS2 derivative, whereas expression of MutS2 at a separate locus in UA948 (the genetically complemented strain) displayed a lower mutation rate and lower transformation frequency than did ΔmutS2. A series of truncated HpMutS2 proteins were purified and tested for their specific abilities to bind 8-oxoG-containing DNA (GO:C) and Holiday Junction structures (HJ). The specific DNA binding domain was localized to an area adjacent to the Smr nuclease domain, and it encompasses 30-amino-acid-residues containing a "KPPKNKFKPPK" motif. Gel shift assays and competition assays supported that a truncated version of HpMutS2-C12 (∼12kDa protein containing the specific DNA-binding domain) has much greater capacity to bind to HJ or GO:C DNA than to normal double stranded DNA. By studying the in vivo roles of the separate domains of HpMutS2, we observed that the truncated versions were unable to complement the ΔmutS2 strain, suggesting the requirement for coordinated function of all the domains in vivo.
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13
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Tambong JT. Comparative genomics of Clavibacter michiganensis subspecies, pathogens of important agricultural crops. PLoS One 2017; 12:e0172295. [PMID: 28319117 PMCID: PMC5358740 DOI: 10.1371/journal.pone.0172295] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 02/02/2017] [Indexed: 11/18/2022] Open
Abstract
Subspecies of Clavibacter michiganensis are important phytobacterial pathogens causing devastating diseases in several agricultural crops. The genome organizations of these pathogens are poorly understood. Here, the complete genomes of 5 subspecies (C. michiganensis subsp. michiganensis, Cmi; C. michiganensis subsp. sepedonicus, Cms; C. michiganensis subsp. nebraskensis, Cmn; C. michiganensis subsp. insidiosus, Cmi and C. michiganensis subsp. capsici, Cmc) were analyzed. This study assessed the taxonomic position of the subspecies based on 16S rRNA and genome-based DNA homology and concludes that there is ample evidence to elevate some of the subspecies to species-level. Comparative genomics analysis indicated distinct genomic features evident on the DNA structural atlases and annotation features. Based on orthologous gene analysis, about 2300 CDSs are shared across all the subspecies; and Cms showed the highest number of subspecies-specific CDS, most of which are mobile elements suggesting that Cms could be more prone to translocation of foreign genes. Cms and Cmi had the highest number of pseudogenes, an indication of potential degenerating genomes. The stress response factors that may be involved in cold/heat shock, detoxification, oxidative stress, osmoregulation, and carbon utilization are outlined. For example, the wco-cluster encoding for extracellular polysaccharide II is highly conserved while the sucrose-6-phosphate hydrolase that catalyzes the hydrolysis of sucrose-6-phosphate yielding glucose-6-phosphate and fructose is highly divergent. A unique second form of the enzyme is only present in Cmn NCPPB 2581. Also, twenty-eight plasmid-borne CDSs in the other subspecies were found to have homologues in the chromosomal genome of Cmn which is known not to carry plasmids. These CDSs include pathogenesis-related factors such as Endocellulases E1 and Beta-glucosidase. The results presented here provide an insight of the functional organization of the genomes of five core C. michiganensis subspecies, enabling a better understanding of these phytobacteria.
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Affiliation(s)
- James T. Tambong
- Ottawa Research and Development Centre (ORDC), Agriculture and Agri-Food Canada, Ottawa, Ontario, Canada
- * E-mail:
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14
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Draper JL, Hansen LM, Bernick DL, Abedrabbo S, Underwood JG, Kong N, Huang BC, Weis AM, Weimer BC, van Vliet AHM, Pourmand N, Solnick JV, Karplus K, Ottemann KM. Fallacy of the Unique Genome: Sequence Diversity within Single Helicobacter pylori Strains. mBio 2017; 8:e02321-16. [PMID: 28223462 PMCID: PMC5358919 DOI: 10.1128/mbio.02321-16] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Accepted: 01/30/2017] [Indexed: 12/30/2022] Open
Abstract
Many bacterial genomes are highly variable but nonetheless are typically published as a single assembled genome. Experiments tracking bacterial genome evolution have not looked at the variation present at a given point in time. Here, we analyzed the mouse-passaged Helicobacter pylori strain SS1 and its parent PMSS1 to assess intra- and intergenomic variability. Using high sequence coverage depth and experimental validation, we detected extensive genome plasticity within these H. pylori isolates, including movement of the transposable element IS607, large and small inversions, multiple single nucleotide polymorphisms, and variation in cagA copy number. The cagA gene was found as 1 to 4 tandem copies located off the cag island in both SS1 and PMSS1; this copy number variation correlated with protein expression. To gain insight into the changes that occurred during mouse adaptation, we also compared SS1 and PMSS1 and observed 46 differences that were distinct from the within-genome variation. The most substantial was an insertion in cagY, which encodes a protein required for a type IV secretion system function. We detected modifications in genes coding for two proteins known to affect mouse colonization, the HpaA neuraminyllactose-binding protein and the FutB α-1,3 lipopolysaccharide (LPS) fucosyltransferase, as well as genes predicted to modulate diverse properties. In sum, our work suggests that data from consensus genome assemblies from single colonies may be misleading by failing to represent the variability present. Furthermore, we show that high-depth genomic sequencing data of a population can be analyzed to gain insight into the normal variation within bacterial strains.IMPORTANCE Although it is well known that many bacterial genomes are highly variable, it is nonetheless traditional to refer to, analyze, and publish "the genome" of a bacterial strain. Variability is usually reduced ("only sequence from a single colony"), ignored ("just publish the consensus"), or placed in the "too-hard" basket ("analysis of raw read data is more robust"). Now that whole-genome sequences are regularly used to assess virulence and track outbreaks, a better understanding of the baseline genomic variation present within single strains is needed. Here, we describe the variability seen in typical working stocks and colonies of pathogen Helicobacter pylori model strains SS1 and PMSS1 as revealed by use of high-coverage mate pair next-generation sequencing (NGS) and confirmed by traditional laboratory techniques. This work demonstrates that reliance on a consensus assembly as "the genome" of a bacterial strain may be misleading.
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Affiliation(s)
- Jenny L Draper
- Institute of Environmental Science and Research, Porirua, New Zealand
- Department of Biomolecular Engineering, UC Santa Cruz, Santa Cruz, California, USA
- Department of Microbiology & Environmental Toxicology, UC Santa Cruz, Santa Cruz, California, USA
| | - Lori M Hansen
- Departments of Medicine and Microbiology & Immunology, Center for Comparative Medicine, UC Davis, California, USA
| | - David L Bernick
- Department of Biomolecular Engineering, UC Santa Cruz, Santa Cruz, California, USA
| | - Samar Abedrabbo
- Department of Microbiology & Environmental Toxicology, UC Santa Cruz, Santa Cruz, California, USA
| | | | - Nguyet Kong
- Department of Population Health and Reproduction, 100K Pathogen Genome Project, UC Davis, Davis, California, USA
| | - Bihua C Huang
- Department of Population Health and Reproduction, 100K Pathogen Genome Project, UC Davis, Davis, California, USA
| | - Allison M Weis
- Department of Population Health and Reproduction, 100K Pathogen Genome Project, UC Davis, Davis, California, USA
| | - Bart C Weimer
- Department of Population Health and Reproduction, 100K Pathogen Genome Project, UC Davis, Davis, California, USA
| | - Arnoud H M van Vliet
- Department of Pathology and Infectious Diseases, School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Nader Pourmand
- Department of Biomolecular Engineering, UC Santa Cruz, Santa Cruz, California, USA
| | - Jay V Solnick
- Departments of Medicine and Microbiology & Immunology, Center for Comparative Medicine, UC Davis, California, USA
| | - Kevin Karplus
- Department of Biomolecular Engineering, UC Santa Cruz, Santa Cruz, California, USA
| | - Karen M Ottemann
- Department of Microbiology & Environmental Toxicology, UC Santa Cruz, Santa Cruz, California, USA
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15
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Dynamic Expansion and Contraction of cagA Copy Number in Helicobacter pylori Impact Development of Gastric Disease. mBio 2017; 8:mBio.01779-16. [PMID: 28223454 PMCID: PMC5358911 DOI: 10.1128/mbio.01779-16] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Infection with Helicobacter pylori is a major risk factor for development of gastric disease, including gastric cancer. Patients infected with H. pylori strains that express CagA are at even greater risk of gastric carcinoma. Given the importance of CagA, this report describes a new molecular mechanism by which the cagA copy number dynamically expands and contracts in H. pylori. Analysis of strain PMSS1 revealed a heterogeneous population in terms of numbers of cagA copies; strains carried from zero to four copies of cagA that were arranged as direct repeats within the chromosome. Each of the multiple copies of cagA was expressed and encoded functional CagA; strains with more cagA repeats exhibited higher levels of CagA expression and increased levels of delivery and phosphorylation of CagA within host cells. This concomitantly resulted in more virulent phenotypes as measured by cell elongation and interleukin-8 (IL-8) induction. Sequence analysis of the repeat region revealed three cagA homologous areas (CHAs) within the cagA repeats. Of these, CHA-ud flanked each of the cagA copies and is likely important for the dynamic variation of cagA copy numbers. Analysis of a large panel of clinical isolates showed that 7.5% of H. pylori strains isolated in the United States harbored multiple cagA repeats, while none of the tested Korean isolates carried more than one copy of cagA. Finally, H. pylori strains carrying multiple cagA copies were differentially associated with gastric disease. Thus, the dynamic expansion and contraction of cagA copy numbers may serve as a novel mechanism by which H. pylori modulates gastric disease development. Severity of H. pylori-associated disease is directly associated with carriage of the CagA toxin. Though the sequences of the CagA protein can differ across strains, previous analyses showed that virtually all H. pylori strains carry one or no copies of cagA. This study showed that H. pylori can carry multiple tandem copies of cagA that can change dynamically. Isolates harboring more cagA copies produced more CagA, thus enhancing toxicity to host cells. Analysis of 314 H. pylori clinical strains isolated from patients in South Korea and the United States showed that 7.5% of clinical strains in the United States carried multiple cagA copies whereas none of the South Korean strains did. This study demonstrated a novel molecular mechanism by which H. pylori dynamically modulates cagA copy number, which affects CagA expression and activity and may impact downstream development of gastric disease.
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16
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Latorre A, Manzano-Marín A. Dissecting genome reduction and trait loss in insect endosymbionts. Ann N Y Acad Sci 2016; 1389:52-75. [DOI: 10.1111/nyas.13222] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Revised: 08/02/2016] [Accepted: 08/08/2016] [Indexed: 11/28/2022]
Affiliation(s)
- Amparo Latorre
- Institut Cavanilles de Biodiversitat I Biologia Evolutiva; Universitat de Valencia; C/Catedrático José Beltrán Paterna Valencia Spain
- Área de Genómica y Salud de la Fundación para el fomento de la Investigación Sanitaria y Biomédica de la Comunitat Valenciana (FISABIO)-Salud Pública; València Spain
| | - Alejandro Manzano-Marín
- Institut Cavanilles de Biodiversitat I Biologia Evolutiva; Universitat de Valencia; C/Catedrático José Beltrán Paterna Valencia Spain
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López-Madrigal S, Latorre A, Moya A, Gil R. The link between independent acquisition of intracellular gamma-endosymbionts and concerted evolution in Tremblaya princeps. Front Microbiol 2015; 6:642. [PMID: 26161080 PMCID: PMC4479817 DOI: 10.3389/fmicb.2015.00642] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 06/12/2015] [Indexed: 02/05/2023] Open
Abstract
Many insect species establish mutualistic symbiosis with intracellular bacteria that complement their unbalanced diets. The betaproteobacterium "Candidatus Tremblaya" maintains an ancient symbiosis with mealybugs (Hemiptera: Pseudococcidae), which are classified in subfamilies Phenacoccinae and Pseudococcinae. Most Phenacoccinae mealybugs have "Candidatus Tremblaya phenacola" as their unique endosymbiont, while most Pseudococcinae mealybugs show a nested symbiosis (a bacterial symbiont placed inside another one) where every "Candidatus Tremblaya princeps" cell harbors several cells of a gammaproteobacterium. Genomic characterization of the endosymbiotic consortium from Planococcus citri, composed by "Ca. Tremblaya princeps" and "Candidatus Moranella endobia," unveiled several atypical features of the former's genome, including the concerted evolution of paralogous loci. Its comparison with the genome of "Ca. Tremblaya phenacola" PAVE, single endosymbiont of Phenacoccus avenae, suggests that the atypical reductive evolution of "Ca. Tremblaya princeps" could be linked to the acquisition of "Ca. Moranella endobia," which possess an almost complete set of genes encoding proteins involved in homologous recombination. In order to test this hypothesis, we performed comparative genomics between "Ca. Tremblaya phenacola" and "Ca. Tremblaya princeps" and searched for the co-occurrence of concerted evolution and homologous recombination genes in endosymbiotic consortia from four unexplored mealybug species, Dysmicoccus boninsis, Planococcus ficus, Pseudococcus longispinus, and Pseudococcus viburni. Our results support a link between concerted evolution and nested endosymbiosis.
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Affiliation(s)
- Sergio López-Madrigal
- Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de ValènciaValència, Spain
| | - Amparo Latorre
- Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de ValènciaValència, Spain
- Área de Genómica y Salud de la Fundación para el Fomento de la Investigación Sanitaria y Biomédica de la Comunitat Valenciana (FISABIO) – Salud PúblicaValència, Spain
| | - Andrés Moya
- Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de ValènciaValència, Spain
- Área de Genómica y Salud de la Fundación para el Fomento de la Investigación Sanitaria y Biomédica de la Comunitat Valenciana (FISABIO) – Salud PúblicaValència, Spain
| | - Rosario Gil
- Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de ValènciaValència, Spain
- *Correspondence: Rosario Gil, Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, C/Catedrático José Beltrán 2, 46980 Paterna, Valencia, Spain
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18
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Genomic characterization of non-mucus-adherent derivatives of Lactobacillus rhamnosus GG reveals genes affecting pilus biogenesis. Appl Environ Microbiol 2014; 80:7001-9. [PMID: 25192985 DOI: 10.1128/aem.02006-14] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Lactobacillus rhamnosus GG is one of the best-characterized lactic acid bacteria and can be considered a probiotic paradigm. Comparative and functional genome analysis showed that L. rhamnosus GG harbors a genomic island including the spaCBA-srtC1 gene cluster, encoding the cell surface-decorating host-interacting pili. Here, induced mutagenesis was used to study pilus biogenesis in L. rhamnosus GG. A combination of two powerful approaches, mutation selection and next-generation sequencing, was applied to L. rhamnosus GG for the selection of pilus-deficient mutants from an enriched population. The isolated mutants were first screened by immuno-dot blot analysis using antiserum against pilin proteins. Relevant mutants were selected, and the lack of pili was confirmed by immunoelectron microscopy. The pilosotype of 10 mutant strains was further characterized by analyzing pilin expression using Western blot, dot blot, and immunofluorescence methods. A mucus binding assay showed that the mutants did not adhere to porcine intestinal mucus. Comparative genome sequence analysis using the Illumina MiSeq platform allowed us to determine the nature of the mutations in the obtained pilus-deficient derivatives. Three major classes of mutants with unique genotypes were observed: class I, with mutations in the srtC1 gene; class II, with a deletion containing the spaCBA-srtC1 gene cluster; and class III, with mutations in the spaA gene. Only a limited number of collateral mutations were observed, and one of the pilus-deficient derivatives with a deficient srtC1 gene contained 24 other mutations. This strain, PB12, can be considered a candidate for human trials addressing the impact of the absence of pili.
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Periwal V, Scaria V. Insights into structural variations and genome rearrangements in prokaryotic genomes. ACTA ACUST UNITED AC 2014; 31:1-9. [PMID: 25189783 DOI: 10.1093/bioinformatics/btu600] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Structural variations (SVs) are genomic rearrangements that affect fairly large fragments of DNA. Most of the SVs such as inversions, deletions and translocations have been largely studied in context of genetic diseases in eukaryotes. However, recent studies demonstrate that genome rearrangements can also have profound impact on prokaryotic genomes, leading to altered cell phenotype. In contrast to single-nucleotide variations, SVs provide a much deeper insight into organization of bacterial genomes at a much better resolution. SVs can confer change in gene copy number, creation of new genes, altered gene expression and many other functional consequences. High-throughput technologies have now made it possible to explore SVs at a much refined resolution in bacterial genomes. Through this review, we aim to highlight the importance of the less explored field of SVs in prokaryotic genomes and their impact. We also discuss its potential applicability in the emerging fields of synthetic biology and genome engineering where targeted SVs could serve to create sophisticated and accurate genome editing.
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Affiliation(s)
- Vinita Periwal
- GN Ramachandran Knowledge Center for Genome Informatics, CSIR Institute of Genomics and Integrative Biology (CSIR-IGIB), Delhi 110007 and Academy of Scientific & Innovative Research (AcSIR), Anusandhan Bhawan, New Delhi 110001, India GN Ramachandran Knowledge Center for Genome Informatics, CSIR Institute of Genomics and Integrative Biology (CSIR-IGIB), Delhi 110007 and Academy of Scientific & Innovative Research (AcSIR), Anusandhan Bhawan, New Delhi 110001, India
| | - Vinod Scaria
- GN Ramachandran Knowledge Center for Genome Informatics, CSIR Institute of Genomics and Integrative Biology (CSIR-IGIB), Delhi 110007 and Academy of Scientific & Innovative Research (AcSIR), Anusandhan Bhawan, New Delhi 110001, India GN Ramachandran Knowledge Center for Genome Informatics, CSIR Institute of Genomics and Integrative Biology (CSIR-IGIB), Delhi 110007 and Academy of Scientific & Innovative Research (AcSIR), Anusandhan Bhawan, New Delhi 110001, India
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20
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A repetitive DNA element regulates expression of the Helicobacter pylori sialic acid binding adhesin by a rheostat-like mechanism. PLoS Pathog 2014; 10:e1004234. [PMID: 24991812 PMCID: PMC4081817 DOI: 10.1371/journal.ppat.1004234] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 05/21/2014] [Indexed: 12/12/2022] Open
Abstract
During persistent infection, optimal expression of bacterial factors is required to match the ever-changing host environment. The gastric pathogen Helicobacter pylori has a large set of simple sequence repeats (SSR), which constitute contingency loci. Through a slipped strand mispairing mechanism, the SSRs generate heterogeneous populations that facilitate adaptation. Here, we present a model that explains, in molecular terms, how an intergenically located T-tract, via slipped strand mispairing, operates with a rheostat-like function, to fine-tune activity of the promoter that drives expression of the sialic acid binding adhesin, SabA. Using T-tract variants, in an isogenic strain background, we show that the length of the T-tract generates multiphasic output from the sabA promoter. Consequently, this alters the H. pylori binding to sialyl-Lewis x receptors on gastric mucosa. Fragment length analysis of post-infection isolated clones shows that the T-tract length is a highly variable feature in H. pylori. This mirrors the host-pathogen interplay, where the bacterium generates a set of clones from which the best-fit phenotypes are selected in the host. In silico and functional in vitro analyzes revealed that the length of the T-tract affects the local DNA structure and thereby binding of the RNA polymerase, through shifting of the axial alignment between the core promoter and UP-like elements. We identified additional genes in H. pylori, with T- or A-tracts positioned similar to that of sabA, and show that variations in the tract length likewise acted as rheostats to modulate cognate promoter output. Thus, we propose that this generally applicable mechanism, mediated by promoter-proximal SSRs, provides an alternative mechanism for transcriptional regulation in bacteria, such as H. pylori, which possesses a limited repertoire of classical trans-acting regulatory factors.
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21
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Dong QJ, Wang LL, Tian ZB, Yu XJ, Jia SJ, Xuan SY. Reduced genome size of Helicobacter pylori originating from East Asia. World J Gastroenterol 2014; 20:5666-5671. [PMID: 24914326 PMCID: PMC4024775 DOI: 10.3748/wjg.v20.i19.5666] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2013] [Revised: 11/19/2013] [Accepted: 01/06/2014] [Indexed: 02/06/2023] Open
Abstract
Helicobacter pylori (H. pylori), a major pathogen colonizing the human stomach, shows great genetic variation. Comparative analysis of strains from different H. pylori populations revealed that the genome size of strains from East Asia decreased to 1.60 Mbp, which is significantly smaller than that from Europe or Africa. In parallel with the genome reduction, the number of protein coding genes was decreased, and the guanine-cytosine content was lowered to 38.9%. Elimination of non-essential genes by mutations is likely to be a major cause of the genome reduction. Bacteria with a small genome cost less energy. Thus, H. pylori strains from East Asia may have proliferation and growth advantages over those from Western countries. This could result in enhanced capacity of bacterial spreading. Therefore, the reduced genome size potentially contributes to the high prevalence of H. pylori in East Asia.
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Coletta-Filho HD, Francisco CS, Almeida RPP. Temporal and spatial scaling of the genetic structure of a vector-borne plant pathogen. PHYTOPATHOLOGY 2014; 104:120-5. [PMID: 24397266 DOI: 10.1094/phyto-06-13-0154-r] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The ecology of plant pathogens of perennial crops is affected by the long-lived nature of their immobile hosts. In addition, changes to the genetic structure of pathogen populations may affect disease epidemiology and management practices; examples include local adaptation of more fit genotypes or introduction of novel genotypes from geographically distant areas via human movement of infected plant material or insect vectors. We studied the genetic structure of Xylella fastidiosa populations causing disease in sweet orange plants in Brazil at multiple scales using fast-evolving molecular markers (simple-sequence DNA repeats). Results show that populations of X. fastidiosa were regionally isolated, and that isolation was maintained for populations analyzed a decade apart from each other. However, despite such geographic isolation, local populations present in year 2000 were largely replaced by novel genotypes in 2009 but not as a result of migration. At a smaller spatial scale (individual trees), results suggest that isolates within plants originated from a shared common ancestor. In summary, new insights on the ecology of this economically important plant pathogen were obtained by sampling populations at different spatial scales and two different time points.
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Fu Y, Zepeda-Gurrola RC, Aguilar-Gutiérrez GR, Lara-Ramírez EE, De Luna-Santillana EJ, Rodríguez-Luna IC, Sánchez-Varela A, Carreño-López R, Moreno-Medina VR, Rodríguez-Pérez MA, López-Vidal Y, Guo X. The detection of inherent homologous recombination between repeat sequences in H. pylori 26695 by the PCR-based method. Curr Microbiol 2013; 68:211-9. [PMID: 24097137 DOI: 10.1007/s00284-013-0466-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Accepted: 08/20/2013] [Indexed: 01/11/2023]
Abstract
Helicobacter pylori infects more than half of the world's population, making it the most widespread infection of bacteria. It has high genetic diversity and has been considered as one of the most variable bacterial species. In the present study, a PCR-based method was used to detect the presence and the relative frequency of homologous recombination between repeat sequences (>500 bp) in H. pylori 26695. All the recombinant structures have been confirmed by sequencing. The inversion generated between inverted repeats showed distinct features from the recombination for duplication or deletion between direct repeats. Meanwhile, we gave the mathematic reasoning of a general formula for the calculation of relative recombination frequency and indicated the conditions for its application. This formula could be extensively applied to detect the frequency of homologous recombination, site-specific recombination, and other types of predictable recombination. Our results should be helpful for better understanding the genome evolution and adaptation of bacteria.
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Affiliation(s)
- Yajuan Fu
- Centro de Biotecnología Genómica, Instituto Politécnico Nacional, Boulevard del Maestro S/N esq. Elías Piña, Col. Narciso Mendoza, Cd., 88710, Reynosa, Tamaulipas, Mexico
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Wang GQ, Xu JT, Xu GY, Zhang Y, Li F, Suo J. Predicting a novel pathogenicity island in Helicobacter pylori by genomic barcoding. World J Gastroenterol 2013; 19:5006-5010. [PMID: 23946608 PMCID: PMC3740433 DOI: 10.3748/wjg.v19.i30.5006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Revised: 06/04/2013] [Accepted: 06/10/2013] [Indexed: 02/06/2023] Open
Abstract
AIM: To apply a new, integrated technique for visualizing bacterial genomes to identify novel pathogenicity islands in Helicobacter pylori (H. pylori).
METHODS: A genomic barcode imaging method (converting frequency matrices to grey-scale levels) was designed to visually distinguish origin-specific genomic regions in H. pylori. The complete genome sequences of the six H. pylori strains published in the National Center for Biotechnological Information prokaryotic genome database were scanned, and compared to the genome barcodes of Escherichia coli (E. coli) O157:H7 strain EDL933 and a random nucleotide sequence. The following criteria were applied to identify potential pathogenicity islands (PAIs): (1) barcode distance distinct from that of the general background; (2) length greater than 10000 continuous base pairs; and (3) containing genes with known virulence-related functions (as determined by PfamScan and Blast2GO).
RESULTS: Comparison of the barcode images generated for the 26695, HPAG1, J99, Shi470, G27 and P12 H. pylori genomes with those for the E. coli and random sequence controls revealed that H. pylori genomes contained fewer anomalous regions. Among the H. pylori-specific continuous anomalous regions (longer than 20 kbp in each strain’s genome), two fit the criteria for identifying candidate PAIs. The bioinformatic-based functional analyses revealed that one of the two anomalous regions was the known pathogenicity island cag-PAI, this finding also served as proof-of-principle for the utility of the genomic barcoding approach for identifying PAIs, and characterized the other as a novel PAI, which was designated as tfs3-PAI. Furthermore, the cag-PAI and tfs3-PAI harbored genes encoding type IV secretion system proteins and were predicted to have potential for functional synergy.
CONCLUSION: Genomic barcode imaging represents an effective bioinformatic-based approach for scanning bacterial genomes, such as H. pylori, to identify candidate PAIs.
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25
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Grove JI, Alandiyjany MN, Delahay RM. Site-specific relaxase activity of a VirD2-like protein encoded within the tfs4 genomic island of Helicobacter pylori. J Biol Chem 2013; 288:26385-96. [PMID: 23900838 PMCID: PMC3772185 DOI: 10.1074/jbc.m113.496430] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Four different type IV secretion systems are variously represented in the genomes of different Helicobacter pylori strains. Two of these, encoded by tfs3 and tfs4 gene clusters are contained within self-transmissible genomic islands. Although chromosomal excision of tfs4 circular intermediates is reported to be dependent upon the function of a tfs4-encoded XerD tyrosine-like recombinase, other factors required for transfer to a recipient cell have not been demonstrated. Here, we characterize the functional activity of a putative tfs4-encoded VirD2-like relaxase protein. Tfs4 VirD2 was purified as a fusion to maltose-binding protein and demonstrated to bind and nick both supercoiled duplex DNA and oligonucleotides in vitro in a manner dependent upon the presence of Mg(2+) but independently of any auxiliary proteins. Unusually, concentration-dependent nicking of duplex DNA appeared to require only transient protein-DNA interaction. Although phylogenetically distinct from established relaxase families, site-specific cleavage of oligonucleotides by Tfs4 VirD2 required the nick region sequence 5'-ATCCTG-3' common to transfer origins (oriT) recognized by MOBP conjugative relaxases. Cleavage resulted in covalent attachment of MBP-VirD2 to the 5'-cleaved end, consistent with conventional relaxase activity. Identification of an oriT-like sequence upstream of tfs4 virD2 and demonstration of VirD2 protein-protein interaction with a putative VirC1 relaxosome component indicate that transfer initiation of the tfs4 genomic island is analogous to mechanisms underlying mobilization of other integrated mobile elements, such as integrating conjugative elements, requiring site-specific targeting of relaxase activity to a cognate oriT sequence.
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Affiliation(s)
- Jane I Grove
- From the Centre for Biomolecular Sciences and Nottingham Digestive Diseases Centre, National Institute for Health Research Biomedical Research Unit, University of Nottingham, Nottingham NG7 2RD, United Kingdom
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Salama NR, Hartung ML, Müller A. Life in the human stomach: persistence strategies of the bacterial pathogen Helicobacter pylori. Nat Rev Microbiol 2013; 11:385-99. [PMID: 23652324 DOI: 10.1038/nrmicro3016] [Citation(s) in RCA: 442] [Impact Index Per Article: 40.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The bacterial pathogen Helicobacter pylori has co-evolved with humans and colonizes approximately 50% of the human population, but only causes overt gastric disease in a subset of infected hosts. In this Review, we discuss the pathogenesis of H. pylori and the mechanisms it uses to promote persistent colonization of the gastric mucosa, with a focus on recent insights into the role of the virulence factors vacuolating cytotoxin (VacA), cytotoxin-associated gene A (CagA) and CagL. We also describe the immunobiology of H. pylori infection and highlight how this bacterium manipulates the innate and adaptive immune systems of the host to promote its own persistence.
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Affiliation(s)
- Nina R Salama
- Division of Human Biology, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Mailstop C3-168, Seattle, Washington 981091024, USA.
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27
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Donkor ES. Understanding the pneumococcus: transmission and evolution. Front Cell Infect Microbiol 2013; 3:7. [PMID: 23471303 PMCID: PMC3590460 DOI: 10.3389/fcimb.2013.00007] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Accepted: 02/12/2013] [Indexed: 11/24/2022] Open
Abstract
Streptococcus pneumoniae is part of the normal bacterial flora of the narsopharynx, but is also associated with several invasive and non-invasive diseases. Recently, there has been a plethora of research information on the pneumococcus, however, there are few comprehensive review papers discussing the research information. This paper provides a review of the pneumococcus in two vital areas related to its biology including transmission and evolution. Transmission of the pneumococcus is a highly efficient process that usually occurs through respiratory droplets from asymptomatic carriers. Following acquisition, the pneumococcus may only establish in the nasopharynx of the new host, or further progress to sites such as the lungs and cause disease. Pneumococcus transmission risk factors, as well as factors involved in its translocation from the nasophyarnx to diseases sites are still not fully understood. Pneumococcal evolution is dominated by recombination. The recombinational events usually involve genetic exchange with streptococci of the mitis group and some pneumococci are thought to exhibit hyper-recombination.
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Affiliation(s)
- Eric S Donkor
- Department of Microbiology, University of Ghana Medical School Accra, Ghana. ;
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Barrozo RM, Cooke CL, Hansen LM, Lam AM, Gaddy JA, Johnson EM, Cariaga TA, Suarez G, Peek RM, Cover TL, Solnick JV. Functional plasticity in the type IV secretion system of Helicobacter pylori. PLoS Pathog 2013; 9:e1003189. [PMID: 23468628 PMCID: PMC3585145 DOI: 10.1371/journal.ppat.1003189] [Citation(s) in RCA: 114] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Accepted: 12/20/2012] [Indexed: 12/13/2022] Open
Abstract
Helicobacter pylori causes clinical disease primarily in those individuals infected with a strain that carries the cytotoxin associated gene pathogenicity island (cagPAI). The cagPAI encodes a type IV secretion system (T4SS) that injects the CagA oncoprotein into epithelial cells and is required for induction of the pro-inflammatory cytokine, interleukin-8 (IL-8). CagY is an essential component of the H. pylori T4SS that has an unusual sequence structure, in which an extraordinary number of direct DNA repeats is predicted to cause rearrangements that invariably yield in-frame insertions or deletions. Here we demonstrate in murine and non-human primate models that immune-driven host selection of rearrangements in CagY is sufficient to cause gain or loss of function in the H. pylori T4SS. We propose that CagY functions as a sort of molecular switch or perhaps a rheostat that alters the function of the T4SS and “tunes” the host inflammatory response so as to maximize persistent infection. Helicobacter pylori is a bacterium that colonizes the stomach of about half the world's population, most of whom are asymptomatic. However, some strains of H. pylori express a bacterial secretion system, a sort of molecular syringe that injects a bacterial protein inside the gastric cells and causes inflammation that can lead to peptic ulcer disease or gastric cancer. One of the essential components of the H. pylori secretion system is CagY, which is unusual because it contains a series of repetitive amino acid motifs that are encoded by a very large number of direct DNA repeats. Here we have shown that DNA recombination in cagY changes the protein motif structure and alters the function of the secretion system—turning it on or off. Using mouse and non-human primate models, we have demonstrated that CagY is a molecular switch that “tunes” the host inflammatory response, and likely contributes to persistent infection. Determining the mechanism by which CagY functions will enhance our understanding of the effects of H. pylori on human health, and could lead to novel applications for the modulation of host cell function.
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Affiliation(s)
- Roberto M. Barrozo
- Center for Comparative Medicine, University of California Davis, Davis, California, United States of America
| | - Cara L. Cooke
- Center for Comparative Medicine, University of California Davis, Davis, California, United States of America
| | - Lori M. Hansen
- Center for Comparative Medicine, University of California Davis, Davis, California, United States of America
| | - Anna M. Lam
- Center for Comparative Medicine, University of California Davis, Davis, California, United States of America
| | - Jennifer A. Gaddy
- Department of Medicine, Vanderbilt University, School of Medicine, Nashville, Tennessee, United States of America
| | - Elizabeth M. Johnson
- Department of Medicine, Vanderbilt University, School of Medicine, Nashville, Tennessee, United States of America
| | - Taryn A. Cariaga
- Center for Comparative Medicine, University of California Davis, Davis, California, United States of America
| | - Giovanni Suarez
- Department of Medicine, Vanderbilt University, School of Medicine, Nashville, Tennessee, United States of America
| | - Richard M. Peek
- Department of Medicine, Vanderbilt University, School of Medicine, Nashville, Tennessee, United States of America
| | - Timothy L. Cover
- Department of Medicine, Vanderbilt University, School of Medicine, Nashville, Tennessee, United States of America
- Department of Microbiology and Immunology, Vanderbilt University, Nashville, Tennessee, United States of America
- Veterans Affairs Tennessee Valley Healthcare System, Nashville, Tennessee, United States of America
| | - Jay V. Solnick
- Center for Comparative Medicine, University of California Davis, Davis, California, United States of America
- Department of Medicine, University of California Davis, School of Medicine, Davis, California, United States of America
- Department of Microbiology and Immunology, University of California Davis, School of Medicine, Davis, California, United States of America
- California National Primate Research Center, University of California Davis, Davis School of Medicine, Davis, California, United States of America
- * E-mail:
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Dong QJ, Zhan SH, Wang LL, Xin YN, Jiang M, Xuan SY. Relatedness of Helicobacter pylori populations to gastric carcinogenesis. World J Gastroenterol 2012; 18:6571-6. [PMID: 23236231 PMCID: PMC3516211 DOI: 10.3748/wjg.v18.i45.6571] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Revised: 08/17/2012] [Accepted: 08/25/2012] [Indexed: 02/06/2023] Open
Abstract
Helicobacter pylori (H. pylori) is a Gram-negative bacterium that infects half of the human population. The infection is associated with chronic inflammation of the gastric mucosa and peptic ulcers. It is also a major risk factor for gastric cancer. Phylogenetic analysis of global strains reveals there are seven populations of H. pylori, including hpAfrica1, hpAfrica2, hpEastAsia, hpEurope, hpNEAfrica, hpAsia2 and hpSahul. These populations are consistent with their geographical origins, and possibly result from geographical separation of the bacterium leading to reduced bacterial recombination in some populations. For each population, H. pylori has evolved to possess genomic contents distinguishable from others. The hpEurope population is distinct in that it has the largest genome of 1.65 mbp on average, and the highest number of coding sequences. This confers its competitive advantage over other populations but at the cost of a lower infection rate. The large genomic size could be a cause of the frequent occurrence of the deletion of the cag pathogenicity island in H. pylori strains from hpEurope. The incidence of gastric cancer varies among different geographical regions. This can be attributed in part to different rates of infection of H. pylori. Recent studies found that different populations of H. pylori vary in their carcinogenic potential and contribute to the variation in incidence of gastric cancer among geographical regions. This could be related to the ancestral origin of H. pylori. Further studies are indicated to investigate the bacterial factors contributing to differential virulence and their influence on the clinical features in infected individuals.
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DprB facilitates inter- and intragenomic recombination in Helicobacter pylori. J Bacteriol 2012; 194:3891-903. [PMID: 22609923 DOI: 10.1128/jb.00346-12] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
For naturally competent microorganisms, such as Helicobacter pylori, the steps that permit recombination of exogenous DNA are not fully understood. Immediately downstream of an H. pylori gene (dprA) that facilitates high-frequency natural transformation is HP0334 (dprB), annotated to be a putative Holliday junction resolvase (HJR). We showed that the HP0334 (dprB) gene product facilitates high-frequency natural transformation. We determined the physiologic roles of DprB by genetic analyses. DprB controls in vitro growth, survival after exposure to UV or fluoroquinolones, and intragenomic recombination. dprB ruvC double deletion dramatically decreases both homologous and homeologous transformation and survival after exposure to DNA-damaging agents. Moreover, the DprB protein binds to synthetic Holliday junction structures rather than double-stranded or single-stranded DNA. These results demonstrate that the dprB product plays important roles affecting inter- and intragenomic recombination. We provide evidence that the two putative H. pylori HJRs (DprB and RuvC) have overlapping but distinct functions involving intergenomic (primarily DprB) and intragenomic (primarily RuvC) recombination.
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Abstract
All organisms have pathways that repair the genome, ensuring their survival and that of their progeny. But these pathways also serve to diversify the genome, causing changes at the nucleotide, whole gene, and genome structure levels. Sequencing of bacteria has revealed wide allelic diversity and differences in gene content within the same species, highlighting the importance of understanding pathways of recombination and DNA repair. The human stomach pathogen Helicobacter pylori is an excellent model system for studying these pathways. H. pylori harbors major recombination and repair pathways and is naturally competent, facilitating its ability to diversify its genome. Elucidation of DNA recombination, repair, and diversification programs in this pathogen will reveal connections between these pathways and their importance to infection.
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Affiliation(s)
- Marion S Dorer
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109-1024, USA.
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Rosenstein R, Götz F. What Distinguishes Highly Pathogenic Staphylococci from Medium- and Non-pathogenic? Curr Top Microbiol Immunol 2012; 358:33-89. [DOI: 10.1007/82_2012_286] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Lara-Ramírez EE, Segura-Cabrera A, Guo X, Yu G, García-Pérez CA, Rodríguez-Pérez MA. New implications on genomic adaptation derived from the Helicobacter pylori genome comparison. PLoS One 2011; 6:e17300. [PMID: 21387011 PMCID: PMC3046158 DOI: 10.1371/journal.pone.0017300] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Accepted: 01/28/2011] [Indexed: 02/07/2023] Open
Abstract
Background Helicobacter pylori has a reduced genome and lives in a tough environment for long-term persistence. It evolved with its particular characteristics for biological adaptation. Because several H. pylori genome sequences are available, comparative analysis could help to better understand genomic adaptation of this particular bacterium. Principal Findings We analyzed nine H. pylori genomes with emphasis on microevolution from a different perspective. Inversion was an important factor to shape the genome structure. Illegitimate recombination not only led to genomic inversion but also inverted fragment duplication, both of which contributed to the creation of new genes and gene family, and further, homological recombination contributed to events of inversion. Based on the information of genomic rearrangement, the first genome scaffold structure of H. pylori last common ancestor was produced. The core genome consists of 1186 genes, of which 22 genes could particularly adapt to human stomach niche. H. pylori contains high proportion of pseudogenes whose genesis was principally caused by homopolynucleotide (HPN) mutations. Such mutations are reversible and facilitate the control of gene expression through the change of DNA structure. The reversible mutations and a quasi-panmictic feature could allow such genes or gene fragments frequently transferred within or between populations. Hence, pseudogenes could be a reservoir of adaptation materials and the HPN mutations could be favorable to H. pylori adaptation, leading to HPN accumulation on the genomes, which corresponds to a special feature of Helicobacter species: extremely high HPN composition of genome. Conclusion Our research demonstrated that both genome content and structure of H. pylori have been highly adapted to its particular life style.
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Affiliation(s)
| | - Aldo Segura-Cabrera
- Centro de Biotecnología Genómica, Instituto Politécnico Nacional, Reynosa, México
| | - Xianwu Guo
- Centro de Biotecnología Genómica, Instituto Politécnico Nacional, Reynosa, México
- * E-mail:
| | - Gongxin Yu
- Department of Biological Sciences, Boise State University, Boise, Idaho, United States of America
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Wang G, Lo LF, Maier RJ. The RecRO pathway of DNA recombinational repair in Helicobacter pylori and its role in bacterial survival in the host. DNA Repair (Amst) 2011; 10:373-9. [PMID: 21292567 DOI: 10.1016/j.dnarep.2011.01.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2010] [Revised: 12/23/2010] [Accepted: 01/04/2011] [Indexed: 12/20/2022]
Abstract
Two pathways for DNA recombination, AddAB (RecBCD-like) and RecRO, were identified in Helicobacter pylori, a pathogenic bacterium that colonizes human stomachs resulting in a series of gastric diseases. In this study, we examined the physiological roles of H. pylori RecRO pathway in DNA recombinational repair. We characterized H. pylori single mutants in recR and in recO, genes in the putative gap repair recombination pathway, and an addA recO double mutant that is thus deficient in both pathways that initiate DNA recombinational repair. The recR or recO single mutants showed the same level of sensitivity to mitomycin C as the parent strain, suggesting that the RecRO pathway is not responsible for the repair of DNA double strand breaks. However, H. pylori recR and recO mutants are highly sensitive to oxidative stress and separately to acid stress, two major stress conditions that H. pylori encounters in its physiological niche. The complementation of the recR mutant restored the sensitivity to oxidative and acid stress to the wild type level. By measuring DNA transformation frequencies, the recR and recO single mutants were shown to have no effect on inter-genomic recombination, whereas the addA recO double mutant had a greatly (∼12-fold) reduced transformation frequency. On the other hand, the RecRO pathway was shown to play a significant role in intra-genomic recombination with direct repeat sequences. Whereas the recA strain had a deletion frequency 35-fold lower than that of background level, inactivation of recR resulted in a 4-fold decrease in deletion frequency. In a mouse infection model, the three mutant strains displayed a greatly reduced ability to colonize the host stomachs. The geometric means of colonization number for the wild type, recR, recO, and addA recO strains were 6 x 10⁵, 1.6 x 10⁴, 1.4 x 10⁴ and 4 x 10³ CFU/g stomach, respectively. H. pylori RecRO-mediated DNA recombinational repair (intra-genomic recombination) is thus involved in repairing DNA damage induced by oxidative and acid stresses and plays an important role in bacterial survival and persistent colonization in the host.
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Affiliation(s)
- Ge Wang
- Department of Microbiology, 815 Biological Sciences Building, University of Georgia, Athens, GA 30602, USA
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Treangen TJ, Rocha EPC. Horizontal transfer, not duplication, drives the expansion of protein families in prokaryotes. PLoS Genet 2011; 7:e1001284. [PMID: 21298028 PMCID: PMC3029252 DOI: 10.1371/journal.pgen.1001284] [Citation(s) in RCA: 319] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2010] [Accepted: 12/20/2010] [Indexed: 01/09/2023] Open
Abstract
Gene duplication followed by neo- or sub-functionalization deeply impacts the evolution of protein families and is regarded as the main source of adaptive functional novelty in eukaryotes. While there is ample evidence of adaptive gene duplication in prokaryotes, it is not clear whether duplication outweighs the contribution of horizontal gene transfer in the expansion of protein families. We analyzed closely related prokaryote strains or species with small genomes (Helicobacter, Neisseria, Streptococcus, Sulfolobus), average-sized genomes (Bacillus, Enterobacteriaceae), and large genomes (Pseudomonas, Bradyrhizobiaceae) to untangle the effects of duplication and horizontal transfer. After removing the effects of transposable elements and phages, we show that the vast majority of expansions of protein families are due to transfer, even among large genomes. Transferred genes--xenologs--persist longer in prokaryotic lineages possibly due to a higher/longer adaptive role. On the other hand, duplicated genes--paralogs--are expressed more, and, when persistent, they evolve slower. This suggests that gene transfer and gene duplication have very different roles in shaping the evolution of biological systems: transfer allows the acquisition of new functions and duplication leads to higher gene dosage. Accordingly, we show that paralogs share most protein-protein interactions and genetic regulators, whereas xenologs share very few of them. Prokaryotes invented most of life's biochemical diversity. Therefore, the study of the evolution of biology systems should explicitly account for the predominant role of horizontal gene transfer in the diversification of protein families.
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Affiliation(s)
- Todd J Treangen
- Institut Pasteur, Microbial Evolutionary Genomics, Département Génomes et Génétique, Paris, France.
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Sirota-Madi A, Olender T, Helman Y, Ingham C, Brainis I, Roth D, Hagi E, Brodsky L, Leshkowitz D, Galatenko V, Nikolaev V, Mugasimangalam RC, Bransburg-Zabary S, Gutnick DL, Lancet D, Ben-Jacob E. Genome sequence of the pattern forming Paenibacillus vortex bacterium reveals potential for thriving in complex environments. BMC Genomics 2010; 11:710. [PMID: 21167037 PMCID: PMC3012674 DOI: 10.1186/1471-2164-11-710] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Accepted: 12/17/2010] [Indexed: 12/05/2022] Open
Abstract
Background The pattern-forming bacterium Paenibacillus vortex is notable for its advanced social behavior, which is reflected in development of colonies with highly intricate architectures. Prior to this study, only two other Paenibacillus species (Paenibacillus sp. JDR-2 and Paenibacillus larvae) have been sequenced. However, no genomic data is available on the Paenibacillus species with pattern-forming and complex social motility. Here we report the de novo genome sequence of this Gram-positive, soil-dwelling, sporulating bacterium. Results The complete P. vortex genome was sequenced by a hybrid approach using 454 Life Sciences and Illumina, achieving a total of 289× coverage, with 99.8% sequence identity between the two methods. The sequencing results were validated using a custom designed Agilent microarray expression chip which represented the coding and the non-coding regions. Analysis of the P. vortex genome revealed 6,437 open reading frames (ORFs) and 73 non-coding RNA genes. Comparative genomic analysis with 500 complete bacterial genomes revealed exceptionally high number of two-component system (TCS) genes, transcription factors (TFs), transport and defense related genes. Additionally, we have identified genes involved in the production of antimicrobial compounds and extracellular degrading enzymes. Conclusions These findings suggest that P. vortex has advanced faculties to perceive and react to a wide range of signaling molecules and environmental conditions, which could be associated with its ability to reconfigure and replicate complex colony architectures. Additionally, P. vortex is likely to serve as a rich source of genes important for agricultural, medical and industrial applications and it has the potential to advance the study of social microbiology within Gram-positive bacteria.
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Affiliation(s)
- Alexandra Sirota-Madi
- The Sackler School of Physics and Astronomy, Tel Aviv University, PO Box 39040, Tel Aviv 69978, Israel
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Kittichotirat W, Bumgarner R, Chen C. Markedly different genome arrangements between serotype a strains and serotypes b or c strains of Aggregatibacter actinomycetemcomitans. BMC Genomics 2010; 11:489. [PMID: 20825670 PMCID: PMC2996985 DOI: 10.1186/1471-2164-11-489] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Accepted: 09/08/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Bacterial phenotype may be profoundly affected by the physical arrangement of their genes in the genome. The Gram-negative species Aggregatibacter actinomycetemcomitans is a major etiologic agent of human periodontitis. Individual clonal types of A. actinomycetemcomitans may exhibit variable virulence and different patterns of disease association. This study examined the genome arrangement of A. actinomycetemcomitans using the genome sequences of serotypes a-c strains. The genome alignment and rearrangement were analyzed by the MAUVE and the GRIMM algorithms. The distribution patterns of genes along the leading/lagging strands were investigated. The occurrence and the location of repeat sequences relative to the genome rearrangement breakpoints were also determined. RESULTS The genome arrangement of the serotype a strain D7S-1 is markedly different from the serotype b strain HK1651 or the serotype c strain D11S-1. Specific genome arrangements appear to be conserved among strains of the same serotypes. The reversal distance between D7S-1 and HK1651 by GRIMM analysis is also higher than the within-species comparisons of 7 randomly selected bacterial species. The locations of the orthologous genes are largely preserved between HK1651 and D11S-1 but not between D7S-1 and HK1651 (or D11S-1), irrespective of whether the genes are categorized as essential/nonessential or highly/nonhighly expressed. However, genome rearrangement did not disrupt the operons of the A. actinomycetemcomitans strains. A higher proportion of the genome in strain D7S-1 is occupied by repeat sequences than in strains HK1651 or D11S-1. CONCLUSION The results suggest a significant evolutionary divergence between serotype a strains and serotypes b/c strains of A. actinomycetemcomitans. The distinct patterns of genome arrangement may suggest phenotypic differences between serotype a and serotypes b/c strains.
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Affiliation(s)
- Weerayuth Kittichotirat
- Division of Periodontology, Diagnostic Sciences and Dental Hygiene, Herman Ostrow School of Dentistry of the University of Southern California, Los Angeles, CA, USA
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Marsin S, Lopes A, Mathieu A, Dizet E, Orillard E, Guérois R, Radicella JP. Genetic dissection of Helicobacter pylori AddAB role in homologous recombination. FEMS Microbiol Lett 2010; 311:44-50. [DOI: 10.1111/j.1574-6968.2010.02077.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Smirnov GB. Repeats in bacterial genome: Evolutionary considerations. MOLECULAR GENETICS, MICROBIOLOGY AND VIROLOGY 2010. [DOI: 10.3103/s0891416810020023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Farnbacher M, Jahns T, Willrodt D, Daniel R, Haas R, Goesmann A, Kurtz S, Rieder G. Sequencing, annotation, and comparative genome analysis of the gerbil-adapted Helicobacter pylori strain B8. BMC Genomics 2010; 11:335. [PMID: 20507619 PMCID: PMC3091624 DOI: 10.1186/1471-2164-11-335] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2009] [Accepted: 05/27/2010] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND The Mongolian gerbils are a good model to mimic the Helicobacter pylori-associated pathogenesis of the human stomach. In the current study the gerbil-adapted strain B8 was completely sequenced, annotated and compared to previous genomes, including the 73 supercontigs of the parental strain B128. RESULTS The complete genome of H. pylori B8 was manually curated gene by gene, to assign as much function as possible. It consists of a circular chromosome of 1,673,997 bp and of a small plasmid of 6,032 bp carrying nine putative genes. The chromosome contains 1,711 coding sequences, 293 of which are strain-specific, coding mainly for hypothetical proteins, and a large plasticity zone containing a putative type-IV-secretion system and coding sequences with unknown function. The cag-pathogenicity island is rearranged such that the cagA-gene is located 13,730 bp downstream of the inverted gene cluster cagB-cag1. Directly adjacent to the cagA-gene, there are four hypothetical genes and one variable gene with a different codon usage compared to the rest of the H. pylori B8-genome. This indicates that these coding sequences might be acquired via horizontal gene transfer.The genome comparison of strain B8 to its parental strain B128 delivers 425 unique B8-proteins. Due to the fact that strain B128 was not fully sequenced and only automatically annotated, only 12 of these proteins are definitive singletons that might have been acquired during the gerbil-adaptation process of strain B128. CONCLUSION Our sequence data and its analysis provide new insight into the high genetic diversity of H. pylori-strains. We have shown that the gerbil-adapted strain B8 has the potential to build, possibly by a high rate of mutation and recombination, a dynamic pool of genetic variants (e.g. fragmented genes and repetitive regions) required for the adaptation-processes. We hypothesize that these variants are essential for the colonization and persistence of strain B8 in the gerbil stomach during in ammation.
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Affiliation(s)
- Max Farnbacher
- Max von Pettenkofer-Institute for Hygiene and Medical Microbiology, Ludwig Maximilian University Munich, 80336 Munich, Germany
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Analysis of DNA repeats in bacterial plasmids reveals the potential for recurrent instability events. Appl Microbiol Biotechnol 2010; 87:2157-67. [PMID: 20496146 DOI: 10.1007/s00253-010-2671-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2010] [Revised: 04/05/2010] [Accepted: 05/05/2010] [Indexed: 12/17/2022]
Abstract
Structural instability has been frequently observed in natural plasmids and vectors used for protein expression or DNA vaccine development. However, there is a lack of information concerning hotspot mapping, namely, DNA repeats or sequences identical to the host genome. This led us to evaluate the abundance and distribution of direct, inverted, and tandem repeats with high recombination potential in 36 natural plasmids from ten bacterial genera, as well as in several widely used bacterial and mammalian expression vectors. In natural plasmids, we observed an overrepresentation of close direct repeats in comparison to inverted ones and a preferential location of repeats with high recombination potential in intergenic regions, suggesting a highly plastic and dynamic behavior. In plasmid vectors, we found a high density of repeats within eukaryotic promoters and non-coding sequences. As a result of this in silico analysis, we detected a spontaneous recombination between two 21-bp direct repeats present in the human cytomegalovirus early enhancer/promoter (huCMV EEP) of the pCIneo plasmid. This finding is of particular importance, as the huCMV EEP is one of the most frequently used regulatory elements in plasmid vectors. Because pDNA integration into host gDNA can have adverse consequences in terms of plasmid processing and host safety, we also mapped several regions with high probability to mediate integration into the Escherichia coli or human genomes. Like repeated regions, some of these were located in non-coding regions of the plasmids, thus being preferential targets to be removed.
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Fischer W, Windhager L, Rohrer S, Zeiller M, Karnholz A, Hoffmann R, Zimmer R, Haas R. Strain-specific genes of Helicobacter pylori: genome evolution driven by a novel type IV secretion system and genomic island transfer. Nucleic Acids Res 2010; 38:6089-101. [PMID: 20478826 PMCID: PMC2952849 DOI: 10.1093/nar/gkq378] [Citation(s) in RCA: 146] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The availability of multiple bacterial genome sequences has revealed a surprising extent of variability among strains of the same species. The human gastric pathogen Helicobacter pylori is known as one of the most genetically diverse species. We have compared the genome sequence of the duodenal ulcer strain P12 and six other H. pylori genomes to elucidate the genetic repertoire and genome evolution mechanisms of this species. In agreement with previous findings, we estimate that the core genome comprises about 1200 genes and that H. pylori possesses an open pan-genome. Strain-specific genes are preferentially located at potential genome rearrangement sites or in distinct plasticity zones, suggesting two different mechanisms of genome evolution. The P12 genome contains three plasticity zones, two of which encode type IV secretion systems and have typical features of genomic islands. We demonstrate for the first time that one of these islands is capable of self-excision and horizontal transfer by a conjugative process. We also show that excision is mediated by a protein of the XerD family of tyrosine recombinases. Thus, in addition to its natural transformation competence, conjugative transfer of genomic islands has to be considered as an important source of genetic diversity in H. pylori.
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Affiliation(s)
- Wolfgang Fischer
- Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie, Ludwig-Maximilians-Universität, Pettenkoferstr. 9a, D-80336 München, Germany.
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Pekhov VM, Krasnova NY, Mazur AM, Selezneva OV, Prokhortchouk EB, Momynaliev KT. Methylation of CpG dinucleotides in the Helicobacter pylori genome at a higher methionine concentration. Mol Biol 2010. [DOI: 10.1134/s002689331001019x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Effects of extremely low-frequency electromagnetic fields on Helicobacter pylori biofilm. Curr Microbiol 2009; 60:412-8. [PMID: 20033173 DOI: 10.1007/s00284-009-9558-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2009] [Accepted: 11/12/2009] [Indexed: 02/08/2023]
Abstract
The aim of this work was to investigate the effects of exposure to extremely low-frequency electromagnetic fields (ELF-EMF) both on biofilm formation and on mature biofilm of Helicobacter pylori. Bacterial cultures and 2-day-old biofilm of H. pylori ATCC 43629 were exposed to ELF-EMF (50 Hz frequency-1 mT intensity) for 2 days to assess their effect on the cell adhesion and on the mature biofilm detachment, respectively. All the exposed cultures and the respective sham exposed controls were studied for: the cell viability status, the cell morphological analysis, the biofilm mass measurement, the genotypic profile, and the luxS and amiA gene expression. The ELF-EMF acted on the bacterial population during the biofilm formation displaying significant differences in cell viability, as well as, in morphotypes measured by the prevalence of spiral forms (58.41%) in respect to the controls (33.14%), whereas, on mature biofilm, no significant differences were found when compared to the controls. The measurement of biofilm cell mass was significantly reduced in exposed cultures in both examined experimental conditions. No changes in DNA patterns were recorded, whereas a modulation in amiA gene expression was detected. An exposure to ELF-EMF of H. pylori biofilm induces phenotypic changes on adhering bacteria and decreases the cell adhesion unbalancing the bacterial population therefore reducing the H. pylori capability to protect itself.
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Momynaliev KT, Kashin SV, Chelysheva VV, Selezneva OV, Demina IA, Serebryakova MV, Alexeev D, Ivanisenko VA, Aman E, Govorun VM. Functional Divergence of Helicobacter pylori Related to Early Gastric Cancer. J Proteome Res 2009; 9:254-67. [DOI: 10.1021/pr900586w] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Kuvat T. Momynaliev
- Research Institute for Physico-Chemical Medicine, Moscow, Russia, Endoscopy, Yaroslavl Regional Oncologic Hospital, Yaroslavl, Russia, Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russia, and Institute of Cytology and Genetics SB RAS, Novosibirsk, Russia
| | - Sergey V. Kashin
- Research Institute for Physico-Chemical Medicine, Moscow, Russia, Endoscopy, Yaroslavl Regional Oncologic Hospital, Yaroslavl, Russia, Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russia, and Institute of Cytology and Genetics SB RAS, Novosibirsk, Russia
| | - Vera V. Chelysheva
- Research Institute for Physico-Chemical Medicine, Moscow, Russia, Endoscopy, Yaroslavl Regional Oncologic Hospital, Yaroslavl, Russia, Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russia, and Institute of Cytology and Genetics SB RAS, Novosibirsk, Russia
| | - Oksana V. Selezneva
- Research Institute for Physico-Chemical Medicine, Moscow, Russia, Endoscopy, Yaroslavl Regional Oncologic Hospital, Yaroslavl, Russia, Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russia, and Institute of Cytology and Genetics SB RAS, Novosibirsk, Russia
| | - Irina A. Demina
- Research Institute for Physico-Chemical Medicine, Moscow, Russia, Endoscopy, Yaroslavl Regional Oncologic Hospital, Yaroslavl, Russia, Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russia, and Institute of Cytology and Genetics SB RAS, Novosibirsk, Russia
| | - Marya V. Serebryakova
- Research Institute for Physico-Chemical Medicine, Moscow, Russia, Endoscopy, Yaroslavl Regional Oncologic Hospital, Yaroslavl, Russia, Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russia, and Institute of Cytology and Genetics SB RAS, Novosibirsk, Russia
| | - Dmitry Alexeev
- Research Institute for Physico-Chemical Medicine, Moscow, Russia, Endoscopy, Yaroslavl Regional Oncologic Hospital, Yaroslavl, Russia, Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russia, and Institute of Cytology and Genetics SB RAS, Novosibirsk, Russia
| | - Vladimir A. Ivanisenko
- Research Institute for Physico-Chemical Medicine, Moscow, Russia, Endoscopy, Yaroslavl Regional Oncologic Hospital, Yaroslavl, Russia, Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russia, and Institute of Cytology and Genetics SB RAS, Novosibirsk, Russia
| | - Ewgeniya Aman
- Research Institute for Physico-Chemical Medicine, Moscow, Russia, Endoscopy, Yaroslavl Regional Oncologic Hospital, Yaroslavl, Russia, Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russia, and Institute of Cytology and Genetics SB RAS, Novosibirsk, Russia
| | - Vadim M. Govorun
- Research Institute for Physico-Chemical Medicine, Moscow, Russia, Endoscopy, Yaroslavl Regional Oncologic Hospital, Yaroslavl, Russia, Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russia, and Institute of Cytology and Genetics SB RAS, Novosibirsk, Russia
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Rosenstein R, Götz F. Genomic differences between the food-grade Staphylococcus carnosus and pathogenic staphylococcal species. Int J Med Microbiol 2009; 300:104-8. [PMID: 19818681 DOI: 10.1016/j.ijmm.2009.08.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
By comparative analyses based on the newly sequenced genome of the meat starter bacterium Staphylococcus carnosus TM300, we observed remarkable differences in the content of mobile genetic elements between non-pathogenic and pathogenic staphylococci. While the latter reveal highly flexible genomes with various mobile elements indicating frequent exchange and rearrangement of genomic material, S. carnosus shows a conspicuous lack of those elements carrying only remnants of a prophage and a genomic island in its genome. Furthermore, the S. carnosus genome is significantly poor in repetitive sequences. Despite being known as completely avirulent, S. carnosus reveals also various gene products with similarity to proteins annotated as virulence factors in S. aureus. In addition, the genome carries a number of mutationally inactivated genes including those of the global regulatory systems agr and sae. Our data indicate that S. carnosus has adapted to the constant environmental conditions encountered as part of a starter culture population by a reductive evolution leading to gene loss and inactivation.
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Affiliation(s)
- Ralf Rosenstein
- Lehrstuhl Mikrobielle Genetik, Universität Tübingen, Waldhäuser Strasse 70/8, D-72076 Tübingen, Germany
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Abstract
The bacterium Helicobacter pylori is remarkable for its ability to persist in the human stomach for decades without provoking sterilizing immunity. Since repetitive DNA can facilitate adaptive genomic flexibility via increased recombination, insertion, and deletion, we searched the genomes of two H. pylori strains for nucleotide repeats. We discovered a family of genes with extensive repetitive DNA that we have termed the H. pylori RD gene family. Each gene of this family is composed of a conserved 3' region, a variable mid-region encoding 7 and 11 amino acid repeats, and a 5' region containing one of two possible alleles. Analysis of five complete genome sequences and PCR genotyping of 42 H. pylori strains revealed extensive variation between strains in the number, location, and arrangement of RD genes. Furthermore, examination of multiple strains isolated from a single subject's stomach revealed intrahost variation in repeat number and composition. Despite prior evidence that the protein products of this gene family are expressed at the bacterial cell surface, enzyme-linked immunosorbent assay and immunoblot studies revealed no consistent seroreactivity to a recombinant RD protein by H. pylori-positive hosts. The pattern of repeats uncovered in the RD gene family appears to reflect slipped-strand mispairing or domain duplication, allowing for redundancy and subsequent diversity in genotype and phenotype. This novel family of hypervariable genes with conserved, repetitive, and allelic domains may represent an important locus for understanding H. pylori persistence in its natural host.
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Abstract
Genomic sequences have been determined for a number of strains of Helicobacter pylori (H pylori) and related bacteria. With the development of microarray analysis and the wide use of subtractive hybridization techniques, comparative studies have been carried out with respect to the interstrain differences between H pylori and inter-species differences in the genome of related bacteria. It was found that the core genome of H pylori constitutes 1111 genes that are determinants of the species properties. A great pool of auxillary genes are mainly from the categories of cag pathogenicity islands, outer membrane proteins, restriction-modification system and hypothetical proteins of unknown function. Persistence of H pylori in the human stomach leads to the diversification of the genome. Comparative genomics suggest that a host jump has occurs from humans to felines. Candidate genes specific for the development of the gastric diseases were identified. With the aid of proteomics, population genetics and other molecular methods, future comparative genomic studies would dramatically promote our understanding of the evolution, pathogenesis and microbiology of H pylori.
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Treangen TJ, Abraham AL, Touchon M, Rocha EPC. Genesis, effects and fates of repeats in prokaryotic genomes. FEMS Microbiol Rev 2009; 33:539-71. [PMID: 19396957 DOI: 10.1111/j.1574-6976.2009.00169.x] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
DNA repeats are causes and consequences of genome plasticity. Repeats are created by intrachromosomal recombination or horizontal transfer. They are targeted by recombination processes leading to amplifications, deletions and rearrangements of genetic material. The identification and analysis of repeats in nearly 700 genomes of bacteria and archaea is facilitated by the existence of sequence data and adequate bioinformatic tools. These have revealed the immense diversity of repeats in genomes, from those created by selfish elements to the ones used for protection against selfish elements, from those arising from transient gene amplifications to the ones leading to stable duplications. Experimental works have shown that some repeats do not carry any adaptive value, while others allow functional diversification and increased expression. All repeats carry some potential to disorganize and destabilize genomes. Because recombination and selection for repeats vary between genomes, the number and types of repeats are also quite diverse and in line with ecological variables, such as host-dependent associations or population sizes, and with genetic variables, such as the recombination machinery. From an evolutionary point of view, repeats represent both opportunities and problems. We describe how repeats are created and how they can be found in genomes. We then focus on the functional and genomic consequences of repeats that dictate their fate.
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Pediatric Helicobacter pylori isolates display distinct gene coding capacities and virulence gene marker profiles. J Clin Microbiol 2009; 47:1680-8. [PMID: 19386830 DOI: 10.1128/jcm.00273-09] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Helicobacter pylori strains display remarkable genetic diversity, and the presence of strains bearing the toxigenic vacA s1 allele, a complete cag pathogenicity island (PAI), cagA alleles containing multiple EPIYA phosphorylation sites, and expressing the BabA adhesin correlates with development of gastroduodenal disease in adults. To better understand the genetic variability present among pediatric strains and its relationship to disease, we characterized H. pylori strains infecting 47 pediatric North American patients. Prevalence of mixed infection was assessed by random amplified polymorphic DNA analysis of multiple H. pylori clones from each patient. Microarray-based comparative genomic hybridization was used to examine the genomic content of the pediatric strains. The cagA and vacA alleles were further characterized by allele-specific PCR. A range of EPIYA motif configurations were observed for the cagA gene, which was present in strains from 22 patients (47%), but only 19 (41%) patients contained a complete cag PAI. Thirty patients (64%) were infected with a strain having the vacA s1 allele, and 28 patients (60%) had the babA gene. The presence of a functional cag PAI was correlated with ulcer disease (P = 0.0095). In spite of declining rates of H. pylori infection in North America, at least 11% of patients had mixed infection. Pediatric strains differ in their spectrum of strain-variable genes and percentage of absent genes in comparison to adult strains. Most children were infected with H. pylori strains lacking the cag PAI, but the presence of a complete cag PAI, in contrast to other virulence markers, was associated with more severe gastroduodenal disease.
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