Transcriptional profiling of Brucella ovis strains cultivated in the presence of high (5%) and low (0.04%) CO2

Wild-type Brucella ovis ATCC 25840 requires the addition of 5% CO2 to the atmosphere to grow on either nutrient agar plates or in liquid broth culture. The goal of this study was to measure the transcriptional response of two Brucella ovis strains under high (5%) and low (0.04%) CO2. The two strains assayed were 1) wild-type and 2) a spontaneous mutant that can be cultivated in standard atmospheric levels of CO2 (~0.04%). Wild-type B. ovis harbors a single nucleotide insertion at the 3' end of a beta carbonic anhydrase gene, bcaA, which renders it non-functional. The spontaneous mutant lost this nucleotide insertion, which restored the consensus reading frame and results in a functional BcaA protein. Triplicate samples of wild-type B. ovis and bcaA1 mutant strains were grown to equivalent OD and the effect of incubation in an atmosphere containing either 5% CO2 or 0.04% CO2 on transcription was measured