Microbial genome dynamics in CNS pathogenesis

Davidsen, Tonje; Koomey, Michael; Tønjum, Tone

doi:10.1016/j.neuroscience.2007.01.059

Cited by 13 publications

(11 citation statements)

References 117 publications

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“…Bacterial meningitis is still after three generations of the availability of efficient antibiotics a major cause of death and disability in children and youngsters worldwide (Lin and Safdieh, 2010). The majority of cases of acute bacterial meningitis are caused by the mucosal opportunistic pathogens Streptococcus pneumoniae (the pneumococcus, Pc), Neisseria meningitidis (the meningococcus, Mc) and Haemophilus influenzae (Davidsen et al, 2007).…”

Section: Aqp4 and Bacterial Meningitismentioning

confidence: 99%

“…Even though the seriousness of S. pneumoniae and N. meningitidis infection is well known, the exact interplay between microbe and host is still elusive (Davidsen and Tonjum, 2006;Weber and Tuomanen, 2007;Orihuela et al, 2009). This has impeded the development of new therapeutic options based on an understanding of the molecular pathogenesis (Davidsen et al, 2007). Undoubtedly, antibiotics can be lifesaving, however, the inflammatory cascade persists after the start of treatment due to release of antigenic components from decaying bacteria, potentially leading to brain edema.…”

Section: Aqp4 and Bacterial Meningitismentioning

confidence: 99%

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Differential effect of α-syntrophin knockout on aquaporin-4 and Kir4.1 expression in retinal macroglial cells in mice

et al. 2006

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Aquaporin-4 water channels and the inwardly rectifying potassium channels Kir4.1 are coexpressed in a highly polarized manner at the perivascular and subvitreal endfeet of retinal Müller cells and astrocytes. The present study was aimed at resolving the anchoring mechanisms responsible for the coexpression of these molecules. Both aquaporin-4 and Kir4.1 contain PDZ-domain binding motifs at their C-termini and it was recently shown that mice with targeted disruption of the dystrophin gene display altered distribution of aquaporin-4 and Kir4.1 in the retina. To test our hypothesis that alpha-syntrophin (a PDZ-domain containing protein of the dystrophin associated protein complex) is involved in aquaporin-4 and Kir4.1 anchoring in retinal cells, we studied the expression pattern of these molecules in alpha-syntrophin null mice. Judged by quantitative immunogold cytochemistry, deletion of the alpha-syntrophin gene causes a partial loss (by 70%) of aquaporin-4 labeling at astrocyte and Müller cell endfeet but no decrease in Kir4.1 labeling at these sites. These findings suggest that alpha-syntrophin is not involved in the anchoring of Kir4.1 and only partly responsible for the anchoring of aquaporin-4 in retinal endfeet membranes. Furthermore we show that wild type and alpha-syntrophin null mice exhibit strong beta1 syntrophin labeling at perivascular and subvitreal Müller cell endfeet, raising the possibility that beta1 syntrophin might be involved in the anchoring of Kir4.1 and the alpha-syntrophin independent pool of aquaporin-4.

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Section: Aqp4 and Bacterial Meningitismentioning

confidence: 99%

Section: Aqp4 and Bacterial Meningitismentioning

confidence: 99%

Differential effect of α-syntrophin knockout on aquaporin-4 and Kir4.1 expression in retinal macroglial cells in mice

et al. 2006

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“…Recent reviews on this topic concluded that there is substantial evidence that HGT contributes to the acquisition, integration and maintenance of pathogenicity islands (PAIs) in bacterial genomes (Hacker et al, 1997(Hacker et al, , 2003Dobrindt et al, 2004Dobrindt et al, , 2010Ahmed et al, 2008). In general, it is widely accepted that HGT significantly impacts the evolution of bacterial genomes and their adaptation to new environments (a nonexhaustive list of reviews on this topic published within this century would be Eisen, 2000;Ochman et al, 2000;Boucher et al, 2001;Koonin et al, 2001;Boucher et al, 2003;Thomas & Nielsen, 2005;Davidsen et al, 2007;Cohan & Koeppel, 2008;Koonin & Wolf, 2008;Ambur et al, 2009;Popa & Dagan, 2011;Stokes & Gillings, 2011;Wiedenbeck & Cohan, 2011).…”

Section: Introductionmentioning

confidence: 99%

Cues and regulatory pathways involved in natural competence and transformation in pathogenic and environmental Gram-negative bacteria

Seitz¹,

Blokesch²

2013

FEMS Microbiol Rev

196

201

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Bacterial genomics is flourishing, as whole-genome sequencing has become affordable, readily available and rapid. As a result, it has become clear how frequently horizontal gene transfer (HGT) occurs in bacteria. The potential implications are highly significant because HGT contributes to several processes, including the spread of antibiotic-resistance cassettes, the distribution of toxin-encoding phages and the transfer of pathogenicity islands. Three modes of HGT are recognized in bacteria: conjugation, transduction and natural transformation. In contrast to the first two mechanisms, natural competence for transformation does not rely on mobile genetic elements but is driven solely by a developmental programme in the acceptor bacterium. Once the bacterium becomes competent, it is able to take up DNA from the environment and to incorporate the newly acquired DNA into its own chromosome. The initiation and duration of competence differ significantly among bacteria. In this review, we outline the latest data on representative naturally transformable Gram-negative bacteria and how their competence windows differ. We also summarize how environmental cues contribute to the initiation of competence in a subset of naturally transformable Gram-negative bacteria and how the complexity of the niche might dictate the fine-tuning of the competence window.

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“…Neisseria meningitidis , the meningococcus, is one of the leading causative agents of meningitis and septicaemia worldwide (Davidsen et al , 2007a). Horizontal gene transfer mediates the exchange of genetic information between bacterial strains and is driven by three processes: conjugation, transformation and transduction.…”

Section: Introductionmentioning

confidence: 99%

Identification of neisserial DNA binding components

Lång¹,

Haugen²,

Fleckenstein

et al. 2009

Microbiology

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Neisseria meningitidis, a causative agent of meningitis and septicaemia, expresses type IV pili, a feature correlating with the uptake of exogenous DNA from the environment by natural transformation. The outer membrane complex PilQ, through which pili are extruded and retracted, has previously been shown to bind DNA in its pore region. In order to further elucidate how DNA is transported across the membranes, we searched for DNA binding proteins within the meningococcal inner membrane. Inner membrane fractions from a panel of neisserial strains were subjected to a solid-phase overlay assay with DNA substrates, and MS was subsequently employed to identify proteins that bind DNA. A number of DNA binding components were detected, including the pilus biogenesis component PilG, the competence protein ComL, and the cell division ATP-binding protein FtsE, as well as two hypothetical proteins. The DNA binding activity of these components was not dependent on the presence of the neisserial DNA uptake sequence. Null mutants, corresponding to each of the proteins identified, were constructed to assess their phenotypes. Only mutants defective in pilus biogenesis were non-competent and non-piliated. The DNA binding activity of the pilus biogenesis components PilQ and PilG and the phenotypes of their respective null mutants suggest that these proteins are directly involved as players in natural transformation, and not only indirectly, through pilus biogenesis.

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Microbial genome dynamics in CNS pathogenesis

Cited by 13 publications

References 117 publications

Differential effect of α-syntrophin knockout on aquaporin-4 and Kir4.1 expression in retinal macroglial cells in mice

Differential effect of α-syntrophin knockout on aquaporin-4 and Kir4.1 expression in retinal macroglial cells in mice

Cues and regulatory pathways involved in natural competence and transformation in pathogenic and environmental Gram-negative bacteria

Identification of neisserial DNA binding components

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