Differential expression of virulence factor genes in <i>B. pertussis</i> and <i>B. parapertussis</i> in response to 5% CO₂ conditions.

<p>qRT-PCR analysis was performed on <i>B. pertussis</i> (A) and <i>B. parapertussis</i> (B) grown in atmospheric or elevated CO₂ conditions. Fold-change expression (FCE) in <i>B. pertussi</i>s and <i>B. parapertussis</i> grown in 5% CO₂ was compared to expression in atmospheric levels of CO₂ and expressed as the mean ± standard deviation. Lysates from bacteria grown in either atmospheric conditions or 5% CO₂ conditions were probed with serum from mice inoculated with either a <i>B. pertussis</i> strain 536 (C) or <i>B. parapertussis</i> strain 12822 (D). The ratio of band intensity between antigens produced in ambient air and 5% CO₂ conditions is indicated in the margins: 1 = equal amounts produced in either conditions, <1 = more produced in ambient air, >1 = more produced in 5% CO₂ conditions.