FIG. 2.

Transcript levels of maltodextrin (A) and pullulanase (B) region genes are increased during growth in a maltotriose-medium and human saliva. Strain MGAS5005 was grown to the mid-exponential or late-exponential phase in either standard laboratory medium (THY), CDM containing 1% maltotriose, or human saliva. TaqMan real-time QRT-PCR was performed using probes and primers listed in Table 2. The transcript levels of target genes were normalized to those of proS, a gene that is expressed constitutively throughout the GAS cell cycle and whose transcript levels are similar when the organism is grown in THY and when the organism is grown in saliva (35, 43). For each gene, the order of bars from left to right is as follows: mid- and late-exponential growth phases in THY, maltotriose-medium, and human saliva. The transcript levels are the means ± standard deviations of quadruplicate measurements obtained on two separate occasions.