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Bartley SN, Tzeng YL, Heel K, Lee CW, Mowlaboccus S, Seemann T, Lu W, Lin YH, Ryan CS, Peacock C, Stephens DS, Davies JK, Kahler CM. Attachment and invasion of Neisseria meningitidis to host cells is related to surface hydrophobicity, bacterial cell size and capsule. PLoS One 2013; 8:e55798. [PMID: 23405216 PMCID: PMC3566031 DOI: 10.1371/journal.pone.0055798] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Accepted: 01/04/2013] [Indexed: 12/13/2022] Open
Abstract
We compared exemplar strains from two hypervirulent clonal complexes, strain NMB-CDC from ST-8/11 cc and strain MC58 from ST-32/269 cc, in host cell attachment and invasion. Strain NMB-CDC attached to and invaded host cells at a significantly greater frequency than strain MC58. Type IV pili retained the primary role for initial attachment to host cells for both isolates regardless of pilin class and glycosylation pattern. In strain MC58, the serogroup B capsule was the major inhibitory determinant affecting both bacterial attachment to and invasion of host cells. Removal of terminal sialylation of lipooligosaccharide (LOS) in the presence of capsule did not influence rates of attachment or invasion for strain MC58. However, removal of either serogroup B capsule or LOS sialylation in strain NMB-CDC increased bacterial attachment to host cells to the same extent. Although the level of inhibition of attachment by capsule was different between these strains, the regulation of the capsule synthesis locus by the two-component response regulator MisR, and the level of surface capsule determined by flow cytometry were not significantly different. However, the diplococci of strain NMB-CDC were shown to have a 1.89-fold greater surface area than strain MC58 by flow cytometry. It was proposed that the increase in surface area without changing the amount of anchored glycolipid capsule in the outer membrane would result in a sparser capsule and increase surface hydrophobicity. Strain NMB-CDC was shown to be more hydrophobic than strain MC58 using hydrophobicity interaction chromatography and microbial adhesion-to-solvents assays. In conclusion, improved levels of adherence of strain NMB-CDC to cell lines was associated with increased bacterial cell surface and surface hydrophobicity. This study shows that there is diversity in bacterial cell surface area and surface hydrophobicity within N. meningitidis which influence steps in meningococcal pathogenesis.
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Affiliation(s)
- Stephanie N. Bartley
- School of Pathology and Laboratory Medicine, The University of Western Australia, Perth, Western Australia, Australia
| | - Yih-Ling Tzeng
- Veterans Affairs Medical Center, Atlanta, Georgia, United States of America
- Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Kathryn Heel
- Centre for Microscopy, Characterisation and Analysis, and Translational Cancer Pathology Laboratory, School of Pathology and Laboratory Medicine, The University of Western Australia, Perth, Western Australia, Australia
| | - Chiang W. Lee
- School of Pathology and Laboratory Medicine, The University of Western Australia, Perth, Western Australia, Australia
| | - Shakeel Mowlaboccus
- School of Pathology and Laboratory Medicine, The University of Western Australia, Perth, Western Australia, Australia
| | - Torsten Seemann
- Victorian Bioinformatics Consortium, Monash University, Melbourne, Victoria, Australia
| | - Wei Lu
- School of Pathology and Laboratory Medicine, The University of Western Australia, Perth, Western Australia, Australia
| | - Ya-Hsun Lin
- Department of Microbiology, Monash University, Melbourne, Victoria, Australia
| | - Catherine S. Ryan
- Department of Microbiology, Monash University, Melbourne, Victoria, Australia
| | - Christopher Peacock
- School of Pathology and Laboratory Medicine, The University of Western Australia, Perth, Western Australia, Australia
| | - David S. Stephens
- Veterans Affairs Medical Center, Atlanta, Georgia, United States of America
- Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - John K. Davies
- Department of Microbiology, Monash University, Melbourne, Victoria, Australia
| | - Charlene M. Kahler
- School of Pathology and Laboratory Medicine, The University of Western Australia, Perth, Western Australia, Australia
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Kong Y, Ma JH, Warren K, Tsang RS, Low DE, Jamieson FB, Alexander DC, Hao W. Homologous recombination drives both sequence diversity and gene content variation in Neisseria meningitidis. Genome Biol Evol 2013; 5:1611-27. [PMID: 23902748 PMCID: PMC3787668 DOI: 10.1093/gbe/evt116] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/23/2013] [Indexed: 01/13/2023] Open
Abstract
The study of genetic and phenotypic variation is fundamental for understanding the dynamics of bacterial genome evolution and untangling the evolution and epidemiology of bacterial pathogens. Neisseria meningitidis (Nm) is among the most intriguing bacterial pathogens in genomic studies due to its dynamic population structure and complex forms of pathogenicity. Extensive genomic variation within identical clonal complexes (CCs) in Nm has been recently reported and suggested to be the result of homologous recombination, but the extent to which recombination contributes to genomic variation within identical CCs has remained unclear. In this study, we sequenced two Nm strains of identical serogroup (C) and multi-locus sequence type (ST60), and conducted a systematic analysis with an additional 34 Nm genomes. Our results revealed that all gene content variation between the two ST60 genomes was introduced by homologous recombination at the conserved flanking genes, and 94.25% or more of sequence divergence was caused by homologous recombination. Recombination was found in genes associated with virulence factors, antigenic outer membrane proteins, and vaccine targets, suggesting an important role of homologous recombination in rapidly altering the pathogenicity and antigenicity of Nm. Recombination was also evident in genes of the restriction and modification systems, which may undermine barriers to DNA exchange. In conclusion, homologous recombination can drive both gene content variation and sequence divergence in Nm. These findings shed new light on the understanding of the rapid pathoadaptive evolution of Nm and other recombinogenic bacterial pathogens.
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Affiliation(s)
- Ying Kong
- Department of Biological Sciences, Wayne State University
| | - Jennifer H. Ma
- Public Health Laboratories, Public Health Ontario, Toronto, Ontario, Canada
| | - Keisha Warren
- Public Health Laboratories, Public Health Ontario, Toronto, Ontario, Canada
- Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Raymond S.W. Tsang
- National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada
| | - Donald E. Low
- Public Health Laboratories, Public Health Ontario, Toronto, Ontario, Canada
- Mount Sinai Hospital, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Frances B. Jamieson
- Public Health Laboratories, Public Health Ontario, Toronto, Ontario, Canada
- Mount Sinai Hospital, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - David C. Alexander
- Public Health Laboratories, Public Health Ontario, Toronto, Ontario, Canada
- Mount Sinai Hospital, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Weilong Hao
- Department of Biological Sciences, Wayne State University
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Tibayrenc M, Ayala FJ. Reproductive clonality of pathogens: a perspective on pathogenic viruses, bacteria, fungi, and parasitic protozoa. Proc Natl Acad Sci U S A 2012; 109:E3305-13. [PMID: 22949662 PMCID: PMC3511763 DOI: 10.1073/pnas.1212452109] [Citation(s) in RCA: 146] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
We propose that clonal evolution in micropathogens be defined as restrained recombination on an evolutionary scale, with genetic exchange scarce enough to not break the prevalent pattern of clonal population structure, a definition already widely used for all kinds of pathogens, although not clearly formulated by many scientists and rejected by others. The two main manifestations of clonal evolution are strong linkage disequilibrium (LD) and widespread genetic clustering ("near-clading"). We hypothesize that this pattern is not mainly due to natural selection, but originates chiefly from in-built genetic properties of pathogens, which could be ancestral and could function as alternative allelic systems to recombination genes ("clonality/sexuality machinery") to escape recombinational load. The clonal framework of species of pathogens should be ascertained before any analysis of biomedical phenotypes (phylogenetic character mapping). In our opinion, this model provides a conceptual framework for the population genetics of any micropathogen.
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Affiliation(s)
- Michel Tibayrenc
- Maladies Infectieuses et Vecteurs Ecologie, Génétique, Evolution et Contrôle, Institut de Rercherche pour le Développement 224, Centre National de la Recherche Scientifique 5290, Universités Montpellier 1 and 2, 34394 Montpellier Cedex 5, France; and
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697
| | - Francisco J. Ayala
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697
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Hubert K, Pawlik MC, Claus H, Jarva H, Meri S, Vogel U. Opc expression, LPS immunotype switch and pilin conversion contribute to serum resistance of unencapsulated meningococci. PLoS One 2012; 7:e45132. [PMID: 23028802 PMCID: PMC3447861 DOI: 10.1371/journal.pone.0045132] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Accepted: 08/13/2012] [Indexed: 01/15/2023] Open
Abstract
Neisseria meningitidis employs polysaccharides and outer membrane proteins to cope with human serum complement attack. To screen for factors influencing serum resistance, an assay was developed based on a colorimetric serum bactericidal assay. The screening used a genetically modified sequence type (ST)-41/44 clonal complex (cc) strain lacking LPS sialylation, polysaccharide capsule, the factor H binding protein (fHbp) and MutS, a protein of the DNA repair mechanism. After killing of >99.9% of the bacterial cells by serum treatment, the colorimetric assay was used to screen 1000 colonies, of which 35 showed enhanced serum resistance. Three mutant classes were identified. In the first class of mutants, enhanced expression of Opc was identified. Opc expression was associated with vitronectin binding and reduced membrane attack complex deposition confirming recent observations. Lipopolysaccharide (LPS) immunotype switch from immunotype L3 to L8/L1 by lgtA and lgtC phase variation represented the second class. Isogenic mutant analysis demonstrated that in ST-41/44 cc strains the L8/L1 immunotype was more serum resistant than the L3 immunotype. Consecutive analysis revealed that the immunotypes L8 and L1 were frequently observed in ST-41/44 cc isolates from both carriage and disease. Immunotype switch to L8/L1 is therefore suggested to contribute to the adaptive capacity of this meningococcal lineage. The third mutant class displayed a pilE allelic exchange associated with enhanced autoaggregation. The mutation of the C terminal hypervariable region D of PilE included a residue previously associated with increased pilus bundle formation. We suggest that autoaggregation reduced the surface area accessible to serum complement and protected from killing. The study highlights the ability of meningococci to adapt to environmental stress by phase variation and intrachromosomal recombination affecting subcapsular antigens.
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Affiliation(s)
- Kerstin Hubert
- University of Würzburg, Institute for Hygiene and Microbiology, Würzburg, Germany
| | | | - Heike Claus
- University of Würzburg, Institute for Hygiene and Microbiology, Würzburg, Germany
| | | | | | - Ulrich Vogel
- University of Würzburg, Institute for Hygiene and Microbiology, Würzburg, Germany
- * E-mail:
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Bratcher HB, Bennett JS, Maiden MCJ. Evolutionary and genomic insights into meningococcal biology. Future Microbiol 2012; 7:873-85. [PMID: 22827308 PMCID: PMC3492750 DOI: 10.2217/fmb.12.62] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Epidemic disease caused by Neisseria meningitidis, the meningococcus, has been recognized for two centuries, but remains incompletely controlled and understood. There have been dramatic reductions in serogroup A and C meningococcal disease following the introduction of protein-polysaccharide conjugate vaccines, but there is currently no comprehensive vaccine against serogroup B meningococci. Genetic analyses of meningococcal populations have provided many insights into the biology, evolution and pathogenesis of this important pathogen. The meningococcus, and its close relative the gonococcus, are the only pathogenic members of the genus Neisseria, and the invasive propensity of meningococci varies widely, with approximately a dozen 'hyperinvasive lineages' responsible for most disease. Despite this, attempts to identify a 'pathogenome', a subset of genes associated with the invasive phenotypes, have failed; however, genome-wide studies of representative meningococcal isolates using high-throughput sequencing are beginning to provide details on the relationship of invasive phenotype and genotype in this fascinating organism and how this relationship has evolved.
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Sjödin A, Svensson K, Öhrman C, Ahlinder J, Lindgren P, Duodu S, Johansson A, Colquhoun DJ, Larsson P, Forsman M. Genome characterisation of the genus Francisella reveals insight into similar evolutionary paths in pathogens of mammals and fish. BMC Genomics 2012; 13:268. [PMID: 22727144 PMCID: PMC3485624 DOI: 10.1186/1471-2164-13-268] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Accepted: 06/07/2012] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Prior to this study, relatively few strains of Francisella had been genome-sequenced. Previously published Francisella genome sequences were largely restricted to the zoonotic agent F. tularensis. Only limited data were available for other members of the Francisella genus, including F. philomiragia, an opportunistic pathogen of humans, F. noatunensis, a serious pathogen of farmed fish, and other less well described endosymbiotic species. RESULTS We determined the phylogenetic relationships of all known Francisella species, including some for which the phylogenetic positions were previously uncertain. The genus Francisella could be divided into two main genetic clades: one included F. tularensis, F. novicida, F. hispaniensis and Wolbachia persica, and another included F. philomiragia and F. noatunensis.Some Francisella species were found to have significant recombination frequencies. However, the fish pathogen F. noatunensis subsp. noatunensis was an exception due to it exhibiting a highly clonal population structure similar to the human pathogen F. tularensis. CONCLUSIONS The genus Francisella can be divided into two main genetic clades occupying both terrestrial and marine habitats. However, our analyses suggest that the ancestral Francisella species originated in a marine habitat. The observed genome to genome variation in gene content and IS elements of different species supports the view that similar evolutionary paths of host adaptation developed independently in F. tularensis (infecting mammals) and F. noatunensis subsp. noatunensis (infecting fish).
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Affiliation(s)
- Andreas Sjödin
- Division of CBRN Security and Defence, FOI - Swedish Defence Research Agency, Umeå, Sweden
| | - Kerstin Svensson
- Division of CBRN Security and Defence, FOI - Swedish Defence Research Agency, Umeå, Sweden
| | - Caroline Öhrman
- Division of CBRN Security and Defence, FOI - Swedish Defence Research Agency, Umeå, Sweden
| | - Jon Ahlinder
- Division of CBRN Security and Defence, FOI - Swedish Defence Research Agency, Umeå, Sweden
| | - Petter Lindgren
- Division of CBRN Security and Defence, FOI - Swedish Defence Research Agency, Umeå, Sweden
| | - Samuel Duodu
- Section for Bacteriology, Norwegian Veterinary Institute, Postbox 750 sentrum, 0106, Oslo, Norway
| | - Anders Johansson
- Department of Clinical Microbiology, Umeå University, SE-901 85, Umeå, Sweden
| | - Duncan J Colquhoun
- Section for Bacteriology, Norwegian Veterinary Institute, Postbox 750 sentrum, 0106, Oslo, Norway
| | - Pär Larsson
- Division of CBRN Security and Defence, FOI - Swedish Defence Research Agency, Umeå, Sweden
| | - Mats Forsman
- Division of CBRN Security and Defence, FOI - Swedish Defence Research Agency, Umeå, Sweden
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Whole genome sequencing to investigate the emergence of clonal complex 23 Neisseria meningitidis serogroup Y disease in the United States. PLoS One 2012; 7:e35699. [PMID: 22558202 PMCID: PMC3338715 DOI: 10.1371/journal.pone.0035699] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Accepted: 03/20/2012] [Indexed: 12/05/2022] Open
Abstract
In the United States, serogroup Y, ST-23 clonal complex Neisseria meningitidis was responsible for an increase in meningococcal disease incidence during the 1990s. This increase was accompanied by antigenic shift of three outer membrane proteins, with a decrease in the population that predominated in the early 1990s as a different population emerged later in that decade. To understand factors that may have been responsible for the emergence of serogroup Y disease, we used whole genome pyrosequencing to investigate genetic differences between isolates from early and late N. meningitidis populations, obtained from meningococcal disease cases in Maryland in the 1990s. The genomes of isolates from the early and late populations were highly similar, with 1231 of 1776 shared genes exhibiting 100% amino acid identity and an average πN = 0.0033 and average πS = 0.0216. However, differences were found in predicted proteins that affect pilin structure and antigen profile and in predicted proteins involved in iron acquisition and uptake. The observed changes are consistent with acquisition of new alleles through horizontal gene transfer. Changes in antigen profile due to the genetic differences found in this study likely allowed the late population to emerge due to escape from population immunity. These findings may predict which antigenic factors are important in the cyclic epidemiology of meningococcal disease.
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Francis AR, Tanaka MM. Evolution of variation in presence and absence of genes in bacterial pathways. BMC Evol Biol 2012; 12:55. [PMID: 22520826 PMCID: PMC3514204 DOI: 10.1186/1471-2148-12-55] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Accepted: 02/17/2012] [Indexed: 11/28/2022] Open
Abstract
Background Bacterial genomes exhibit a remarkable degree of variation in the presence and absence of genes, which probably extends to the level of individual pathways. This variation may be a consequence of the significant evolutionary role played by horizontal gene transfer, but might also be explained by the loss of genes through mutation. A challenge is to understand why there would be variation in gene presence within pathways if they confer a benefit only when complete. Results Here, we develop a mathematical model to study how variation in pathway content is produced by horizontal transfer, gene loss and partial exposure of a population to a novel environment. Conclusions We discuss the possibility that variation in gene presence acts as cryptic genetic variation on which selection acts when the appropriate environment occurs. We find that a high level of variation in gene presence can be readily explained by decay of the pathway through mutation when there is no longer exposure to the selective environment, or when selection becomes too weak to maintain the genes. In the context of pathway variation the role of horizontal gene transfer is probably the initial introduction of a complete novel pathway rather than in building up the variation in a genome without the pathway.
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Affiliation(s)
- Andrew R Francis
- School of Computing, Engineering and Mathematics, University of Western Sydney, Penrith 2751, Locked Bag 1797, Australia.
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Yi H, Cho YJ, Yoon SH, Park SC, Chun J. Comparative genomics of Neisseria weaveri clarifies the taxonomy of this species and identifies genetic determinants that may be associated with virulence. FEMS Microbiol Lett 2012; 328:100-5. [PMID: 22188430 DOI: 10.1111/j.1574-6968.2011.02485.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Revised: 12/09/2011] [Accepted: 12/09/2011] [Indexed: 11/29/2022] Open
Abstract
A group of bacterial strains formerly known as CDC group M-5 are opportunistic pathogens to humans. In 1993, a name, Neisseria weaveri, was proposed by two independent studies to harbor CDC group M-5 strains, namely N. weaveri Holmes et al. 1993 and N. weaveri Andersen et al. 1993, with two different 'type' strains. However, no study has been conducted on to the relatedness of the two 'type' strains, although the close relationship of the two taxa has long been accepted unofficially. Formally, the status of the name N. weaveri Andersen et al. 1993 is illegitimate because it is a later homonym of N. weaveri Holmes et al., 1993; but the name of the strain is still validly published. In this study, we attempt to resolve the confusion caused by the apparent duplication of the species N. weaveri (with different type strains) using whole genome shotgun sequencing. We also sought to gain insight into the genetic characteristics of N. weaveri by conducting comparative genomics. On the basis of genomic similarities revealed through a comparative genomic study, we propose that N. weaveri Andersen et al. 1993 should be re-classified as a later heterotypic synonym of N. weaveri Holmes et al., 1993.
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Affiliation(s)
- Hana Yi
- Institute of Molecular Biology and Genetics, Seoul, Korea
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