Validation of microarray data using qRT-PCR.

RNA from three biological replicates of P. gingivalis ATCC 33277, ECR455 and ECR475 grown in batch culture was extracted, then 800 ng RNA was reverse transcribed using random hexamers, before 0.3 ng cDNA was used as template in real time PCR with Power SYBR Green PCR master mix (Applied Biosystems) for 35 cycles. The number of copies of transcript was quantified relative to a standard curve amplified from 33277 genomic DNA for each primer pair. The mean number of transcripts from each bacterial strain was calculated for each primer pair and then used to calculate the qRT-PCR fold ratios.Validation of microarray data using qRT-PCR.