Project description:The classical bordetellae (Bordetella pertussis, B. parapertussis, and B. bronchiseptica) are obligate aerobes that use only oxygen as their terminal electron acceptor for electron transport-coupled oxidative phosphorylation. Therefore, access to oxygen is critical for these bacteria to survive. To better understand how B. bronchiseptica changes its gene regulation when faced with different levels of oxygen, we grew liquid cultures of B. bronchiseptica RB50 in ambient air, 5% oxygen, and 2% oxygen. We also measured how the presence of 5% carbon dioxide affected gene expression in these bacteria, since they are respiratory pathogens and therefore get exposed to higher carbon dioxide levels during infection than are found in ambient air.
Project description:Bordetella bronchiseptica RB50 was shifted from iron replete to either iron depleted or iron replete media, and samples were taken post shift for transcriptional profiling
Project description:The respiratory tract is constantly exposed to the environment and displays a favorable niche for colonizing microorganisms. However, the effects of respiratory bacterial carriage on the immune system and its implications for secondary responses remain largely unclear. We have employed respiratory carriage with Bordetella bronchiseptica (Bb) as the underlying model to comprehensively address effects on subsequent immune responses. Persistent carriage was associated with the stimulation of Bordetella-specific CD4+, CD8+ and CD4+CD25+Foxp3+ T cell responses and broad transcriptional activation was observed in CD4+CD25+ T cells. Importantly, transfer of lymphocytes from persistent carriers to acutely B. bronchiseptica infected mice resulted in a significantly increased bacterial burden in the recipient’s upper respiratory tract. In contrast, we found that B. bronchiseptica carriage resulted in a significant benefit for the host in systemic infection with Listeria monocytogenes. At the same time, vaccination and influenza A virus infection were unaffected. These data demonstrate that there are significant immune modulatory processes triggered by persistent B. bronchiseptica carriage that differentially affect subsequent immune responses. Thereby our results demonstrate the complexity of immune regulation induced by persistent bacterial carriage in the respiratory tract that can be beneficial or detrimental to the host, depending on the pathogen and the considered compartment.
Project description:Comparative genome hybridization (CGH) of sample of 58 Bordetella bronchiseptica, B. pertussis, and B. parapertussis strains selected to span four clusters as defined by MLST.