Expression of the ndh gene in B. cenocepacia K56-2, K56-dI2, and K56-R2. Total RNA was extracted from 8, 12, and 16 cultures and subjected to real-time RT-PCR. The absolute expression levels were determined using an ndh standard curve. The values are means ± standard deviations for triplicate assays. Solid bars, K56-2; open bars, K56-dI2; gray bars, K56-R2.