Effect of oxygen and carbon dioxide on gene expression in Bordetella bronchiseptica strain RB50

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. We grew wild-type RB50 in shaking liquid cultures in either ambient air, 5% O2, 2% O2, or 5% CO2. We then assessed gene expression of bacteria in these conditions. Differential gene expression was determined between bacteria grown in ambient air and bacteria grown under conditions (i.e. air vs. 5% O2, air vs 2% O2, and air vs 5% CO2).