ORCID Profile
0000-0002-1623-0295
Current Organisation
University of Oxford
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Publisher: Springer Science and Business Media LLC
Date: 12-02-2016
DOI: 10.1038/SREP21015
Abstract: Neisseria meningitidis is a human-specific bacterium that varies in invasive potential. All meningococci are carried in the nasopharynx, and most genotypes are very infrequently associated with invasive meningococcal disease however, those belonging to the ‘hyperinvasive lineages’ are more frequently associated with sepsis or meningitis. Genome content is highly conserved between carriage and disease isolates, and differential gene expression has been proposed as a major determinant of the hyperinvasive phenotype. Three phase variable DNA methyltransferases (ModA, ModB and ModD), which mediate epigenetic regulation of distinct phase vari able regul ons (phasevarions), have been identified in N. meningitidis . Each mod gene has distinct alleles, defined by their Mod DNA recognition domain, and these target and methylate different DNA sequences, thereby regulating distinct gene sets. Here 211 meningococcal carriage and ,400 disease isolates were surveyed for the distribution of meningococcal mod alleles. While modA11 - 12 and modB1-2 were found in most isolates, rarer alleles ( e.g., modA15, modB4, modD1-6) were specific to particular genotypes as defined by clonal complex. This suggests that phase variable Mod proteins may be associated with distinct phenotypes and hence invasive potential of N. meningitidis strains.
Publisher: Springer Science and Business Media LLC
Date: 14-03-2017
DOI: 10.1038/SREP44442
Abstract: Pathogenic meningococci have acquired a 24 kb capsule synthesis island ( cps ) by horizontal gene transfer which consists of a synthetic locus and associated capsule transport genes flanked by repetitive Regions D and D’. Regions D and D’ contain an intact gene encoding a UDP-galactose epimerase ( galE1 ) and a truncated remnant ( galE2 ), respectively. In this study, GalE protein alleles were shown to be either mono-functional, synthesising UDP-galactose (UDP-Gal), or bi-functional, synthesising UDP-Gal and UDP-galactosamine (UDP-GalNAc). Meningococci possessing a capsule null locus ( cnl ) typically possessed a single bi-functional galE . Separation of functionality between galE1 and galE2 alleles in meningococcal isolates was retained for all serogroups except serogroup E which has a synthetic requirement for UDP-GalNAc. The truncated galE2 remnant in Region D’ was also phylogenetically related to the bi-functional galE of the cnl locus suggesting common ancestry. A model is proposed in which the illegitimate recombination of the cps island into the galE allele of the cnl locus results in the formation of Region D’ containing the truncated galE2 locus and the capture of the cps island en bloc. The retention of the duplicated Regions D and D’ enables inversion of the synthetic locus within the cps island during bacterial growth.
Publisher: Public Library of Science (PLoS)
Date: 24-04-2009
Publisher: Microbiology Society
Date: 08-2011
Abstract: Invasive disease caused by the encapsulated bacteria Neisseria meningitidis , Haemophilus influenzae and Streptococcus pneumoniae remains an important cause of morbidity and mortality worldwide, despite the introduction of successful conjugate polysaccharide vaccines that target disease-associated strains. In addition, resistance, or more accurately reduced susceptibility, to therapeutic antibiotics is spreading in populations of these organisms. There is therefore a continuing requirement for the surveillance of vaccine and non-vaccine antigens and antibiotic susceptibilities among isolates from invasive disease, which is only partially met by conventional methods. This need can be met with molecular and especially nucleotide sequence-based typing methods, which are fully developed in the case of N. meningitidis and which could be more widely deployed in clinical laboratories for S. pneumoniae and H. influenzae .
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Odile Harrison.