Project description:Neisseria meningitidis is a major cause of bacterial meningitis and septicemia worldwide. Seven new serogroup C meningococci were isolated from two provinces of China in January, 2006. Their PorA VR types were P1.20, 9. Multilocus sequence typing results indicated that they all belonged to ST-7. It is a new serogroup C N. meningitidis sequence type clone identified in China. Here we also present the results of a genomic comparison of these isolates with other 15 N. meningitidis serogroup A and B isolates, which belonged to ST-7, based on comparative genomic hybridization analysis. The data described here would be helpful to monitor the spread of this new serogroup C meningococci sequence type clone in China and worldwide. Keywords: comparative genomic hybridization
Project description:Neisseria meningitidis is an obligate commensal colonising the human nasopharynx and occasionally invades the bloodstream causing life-threatening meningitis and septicaemia. The gene NMB0419 on the genome of N. meningitidis MC58 encodes a putative Sel1-like repeat (SLR) containing protein, which has been implicated in mediating meningococcal invasion of epithelial cells. We prepared RNA samples from N. meningitidis MC58 (WT) and its isogenic mutant of NMB0419 grown to log phase in in-vitro culture. The RNA samples were subjected to RNA sequencing. The resulting transcriptomes were compared to determine the genes that differentially expressed in NMB0419 mutant.
Project description:In Neisseria meningitidis iron responsive gene regulation is mediated primarily by the Ferric Uptake Regulator (Fur) protein. When complexed with iron, Fur represses gene expression by preventing transcription initiation. Fur can also indirectly activate gene expression via the repression of regulatory small RNAs (sRNA). One such Fur-and iron-regulated sRNA, NrrF, was previously identified in N. meningitidis and shown to repress expression of the sdhA and sdhC genes encoding subunits of the succinate dehydrogenase complex. In the majority of Gram-negative bacteria sRNA-mediated regulation requires a cofactor RNA-binding protein (Hfq) for proper gene regulation and stabilization. In this study we examined the role of Hfq in NrrF-mediated regulation of the succinate dehydrogenase genes in N. meningitidis and the effect of an hfq- mutation on iron-responsive gene regulation more broadly. We first demonstrated that the stability of Nrrf as well as the regulation of sdhC and sdhA in vivo was unaltered in the hfq- mutant. Secondly, we established that iron responsive gene regulation of the Fur-regulated sodB gene was dependent on Hfq. Finally, we demonstrate that in N. meningitidis Hfq functions to control expression of both ORFs and intergenic regions via iron independent mechanisms. Collectively these studies demonstrate that in N. meningitidis iron and NrrF mediated regulation of sdhC and sdhA can occur independently of Hfq, although Hfq functions more globally to control regulation of other N. meningitidis genes primarily by iron-independent mechanisms.
Project description:Neisseria meningitidis is the leading cause of bacterial meningitis and septicemia worldwide. The novel ST-4821 clonal complex caused several serogroup C meningococcal outbreaks unexpectedly during 2003–2005 in China. We fabricated a whole-genome microarray of Chinese N. meningitidis serogroup C representative isolate 053442 and characterized 27 ST-4821 complex isolates which were isolated from different serogroups using comparative genomic hybridization (CGH) analysis. This paper provides important clues which are helpful to understand the genome composition and genetic background of different serogroups isolates, and possess significant meaning to the study of the newly emerged hyperinvasive lineage. Keywords: comparative genomic hybridization
Project description:We looked at host gene expression signatures common and specfic to occasionally pathogenic N. meningitidis and commensal N. lactamica. We hypothesise that similar host cell responses during early interactions with N. meningitidis and N. lactamica could inform common mechanisms of colonisation of commensals while differential host cell responses could be capable of altering the outcome of the colonisation process.
Project description:Baart2007 - Genome-scale metabolic network of
Neisseria meningitidis (iGB555)
This model is described in the article:
Modeling Neisseria
meningitidis metabolism: from genome to metabolic fluxes.
Baart GJ, Zomer B, de Haan A, van
der Pol LA, Beuvery EC, Tramper J, Martens DE.
Genome Biol. 2007; 8(7): R136
Abstract:
BACKGROUND: Neisseria meningitidis is a human pathogen that
can infect diverse sites within the human host. The major
diseases caused by N. meningitidis are responsible for death
and disability, especially in young infants. In general, most
of the recent work on N. meningitidis focuses on potential
antigens and their functions, immunogenicity, and pathogenicity
mechanisms. Very little work has been carried out on Neisseria
primary metabolism over the past 25 years. RESULTS: Using the
genomic database of N. meningitidis serogroup B together with
biochemical and physiological information in the literature we
constructed a genome-scale flux model for the primary
metabolism of N. meningitidis. The validity of a simplified
metabolic network derived from the genome-scale metabolic
network was checked using flux-balance analysis in chemostat
cultures. Several useful predictions were obtained from in
silico experiments, including substrate preference. A minimal
medium for growth of N. meningitidis was designed and tested
successfully in batch and chemostat cultures. CONCLUSION: The
verified metabolic model describes the primary metabolism of N.
meningitidis in a chemostat in steady state. The genome-scale
model is valuable because it offers a framework to study N.
meningitidis metabolism as a whole, or certain aspects of it,
and it can also be used for the purpose of vaccine process
development (for example, the design of growth media). The flux
distribution of the main metabolic pathways (that is, the
pentose phosphate pathway and the Entner-Douderoff pathway)
indicates that the major part of pyruvate (69%) is synthesized
through the ED-cleavage, a finding that is in good agreement
with literature.
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