Αρχειοθήκη ιστολογίου

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Τρίτη 20 Σεπτεμβρίου 2022

Transition Metals and Enterococcus faecalis: Homeostasis, Virulence and Perspectives

alexandrossfakianakis shared this article with you from Inoreader

Abstract

Enterococcus faecalis, a Gram-positive bacterium is known to be a key player in several chronic infections as well as nosocomial, heart valve, urinary tract, surgical wound and dental root canal infections. The capability to sense different transition metal levels and tune its response accordingly endows it with the potential to thrive and cause infections in several host niches. Over the past decade, our knowledge of how transition metals play a critical role in maintaining homeostasis of E. faecalis has improved significantly. The aim of this review is to elucidate the roles of metals such as iron, manganese, zinc and copper in the physiology, metabolism, and pathogenicity of E. faecalis. These essential micronutrients contribute to energy production, redox stress response, expression of virulence determinants, and cooperation in polymicrobial communities. The review also highlights metal homeostasis systems in E. faecalis, which respond to fluctuatio ns in extracellular metal levels, and regulate the intracellular metal content. Regulation of intracellular metallome secures the tolerance of E. faecalis to oxidative stress and host-mediated metal sequestration strategies. Therapeutic interventions which deprive E. faecalis of its essential metal requirements or disrupt its homeostatic control have been proposed to combat E. faecalis infections.

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The problem with picking: Permittance, escape and shame in problematic skin picking

alexandrossfakianakis shared this article with you from Inoreader

Abstract

Objectives

Problematic skin picking (SP) is a poorly understood experience characterised by a drive to pick the skin and related psychosocial impact. In the DSM-5, problematic SP is classified as 'excoriation (skin picking) disorder'. The aim of this article is to present a rare qualitative perspective on the lived experience of problematic SP, prioritising participants' voices and sense-making.

Design

An in-depth qualitative study of individuals who self-identified as picking their skin problematically and experienced related distress.

Methods

Seventeen UK-based participants were recruited online and interviewed about their SP. Participants were given choice of interview modality, including instant messenger platforms, telephone, email and Skype, to maximise comfort and improve the accessibility of the study. Transcripts were analysed using thematic analysis.

Results

Three themes offering novel insight into the phenomenology of participants' SP are highlighted and explored: (1) how cognitions and circumstances drove and permitted SP, (2) how participants 'zoned out' while SP and the escape or relief that this attentional experience offered and (3) participants' feelings of shame and distress in how they felt their SP may appear to others.

Conclusions

This study contributes in-depth and novel ideas to the understanding of SP phenomenology and identifies how environmental factors, cognitions, contextual distress and shame may be considerations in therapeutic intervention. It presents the complexity of SP sense-making and demonstrates the need for individual formulation.

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Tobacco smoke exacerbates Filifactor alocis pathogenicity

alexandrossfakianakis shared this article with you from Inoreader

Abstract

Aims

Filifactor alocis has recently emerged as a periodontal pathobiont that appears to thrive in the oral cavity of smokers. We hypothesized that identification of smoke-responsive F. alocis genes would provide insight into adaptive strategies and that cigarette smoke would enhance F. alocis pathogenesis in vivo.

Materials and Methods

F. alocis was grown in vitro and cigarette smoke extract-responsive genes determined by RNAseq. Mice were exposed, or not, to mainstream 1R6F research cigarette smoke and infected with F. alocis, or not, in an acute ligature model of periodontitis. Key clinical, infectious, and immune data were collected.

Results

In culture, F. alocis growth was unaffected by smoke conditioning and only a small number of genes were specifically regulated by smoke exposure. Reduced murine mass, differences in F. alocis-cognizant antibody production and altered immune profiles as well as altered alveolar bone loss were all attributable to smoke exposure and/or F. alocis infection in vivo.

Conclusions

F. alocis is well-adapted to tobacco-rich conditions and its pathogenesis is enhanced by tobacco smoke exposure. A smoke-exposed ligature model of periodontitis shows promise as a tool with which to further unravel mechanisms underlying tobacco-enhanced, bacteria-induced disease.

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