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 is a gram-negative respiratory pathogen that causes a diverse spectrum of respiratory disease in a wide-range of hosts. We sought to determine if strains of B. bronchiseptica differed in virulence using the mouse model of infection. Mean lethal doses (LD50) of different B. bronchiseptica strains varied widely in the murine model. B. bronchiseptica strain 253 had a LD50 that was 10-fold lower than the prototypical and fully sequenced B. bronchiseptica strain RB50. Using whole genomic transcriptome analysis covering 100% of B. bronchisetpctica strain RB50ÃÂÃÂs predicted open reading frames (ORFs), 253 was identified as lacking expression of adenylate cyclase toxin (ACT).
Project description:B. bronchiseptica RB50 was grown in medium either lacking or containing iron (ferrous sulfate). At various time points, samples were taken for gene expression analysis.
Project description:Bordetella bronchiseptica is a gram-negative respiratory pathogen that causes a diverse spectrum of respiratory disease in a wide-range of hosts. We sought to determine if strains of B. bronchiseptica differed in virulence using the mouse model of infection. Mean lethal doses (LD50) of different B. bronchiseptica strains varied widely in the murine model. B. bronchiseptica strain 253 had a LD50 that was 10-fold lower than the prototypical and fully sequenced B. bronchiseptica strain RB50. Using whole genomic transcriptome analysis covering 100% of B. bronchisetpctica strain RB50ÃÂs predicted open reading frames (ORFs), 253 was identified as lacking expression of adenylate cyclase toxin (ACT). Using whole genomic comparative genomic hybridization analysis and whole genome sequencing, we determined that the cya operon, which is required for ACT production, was absent from the 253 genome.
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:Copper is both essential and toxic to living beings, which therefore tightly control its intracellular concentration. At the host-pathogen interface, copper is used by phagocytic cells to kill invading microorganisms. We investigated copper homeostasis in the whooping cough agent Bordetella pertussis, which lives in the human respiratory mucosa and has no environmental reservoir. B. pertussis has considerably streamlined copper homeostasis mechanisms relative to other Gram-negative bacteria. Its single remaining defense line against copper intoxication consists in a metallochaperone diverted for copper passivation and two enzymes involved in peroxide detoxification, which together fight two stresses encountered in phagolysosomes. The three proteins are encoded by an original, composite operon assembled in an environmental ancestor and which is under sensitive control by copper. Interestingly, this system appears to play a role in persistent infection in the nasal cavity of B. pertussis-infected mice. Combining responses to co-occurring stresses in a tailored operon reveals a new strategy adopted by a host-restricted pathogen to optimize survival at minimal energy expenditure.
