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Browsing by Author "Santos, Pedro Miguel Viegas dos"

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  • Identification and characterization of prophages in Bacteroides spp. isolates from children with type 1 diabetes
    Publication . Santos, Pedro Miguel Viegas dos; Faleiro, Leonor; Duarte, Isabel
    Identification and characterization of bacteriophages (phages) in gut microbiome (phageome) has been through the years a difficult task. Bacteriophages display the tools to modulate the bacterial populations in the gut through their abundance and diversity ultimately resulting in dysbiosis. The trigger that starts the metabolic cascade that leads to the onset of type 1 diabetes (T1D) may come via an ample source of biological identities, one of which can be the viral patterns in the bacterial communities. A tool that greatly facilitates the detection of prophages in bacterial genomes is the PHAge Search Tool Enhanced Release (PHASTER) that was used in this study to analyze the prophage patterns of 7 Bacteroides dorei strains and 1 Parabacteroides distasonis strain that were isolated from children with T1D and healthy Controls. In the current study 9 incomplete prophages (cryptic prophages) were identified and characterized in 7 B. dorei strains and in the P. distasonis strain. Prophage-like regions in Bacteroides isolates from T1D children carrying genes potentially impacting or triggering the autoimmunity attack of β-cells to the onset of T1D were identified. A coding gene for a DEAD/DEAH box helicase in B. dorei D8M1 genome and a DNA adenine methylase (dam) gene encountered in B. dorei D16P1 and D16M14 strains. To establish if stress conditions could trigger the lytic cycle, particularly the exposure of the bacterial strains to mitomycin C, ox-bile and hydrogen peroxide was evaluated. No phage induction was observed under the exposure to the tested inducers. The role of the intestinal virome in the development of T1D is scarce to provide answers for the autoimmune attack of β-cells, but the identification of the dam gene in B. dorei strains isolated from T1D children evidences that it will be important to dissect its role on the bacterial physiology and its impact on the seroconversion.
    2020-01-27Master thesis Open access Show more