Figure 2.

Promoter activity assays and transcript level quantitation of RrrR. (A) Specific β-galactosidase activities of plasmids containing RrrR(+) and RrrR(−) promoter sequences were assayed for S. acidocaldarius MW001 cells during exponential growth (48h). A mutated TATA box version (Supplementary Table S1) was employed as negative control for each promoter. (B) Total RNA isolated from S. acidocaldarius MW001 grown either as biofilm or planktonic cultures were used for cDNA synthesis. qRT-PCR analysis was performed using specific primers for the RrrR(+) (blue bar) and RrrR(−) (red bar) transcripts. The values reflect the fold change in gene expression compared with cDNA prepared from exponential grown planktonic cells, which is designated as baseline. (C) Total RNA was isolated from cells grown as biofilms. Transcript levels of both RrrR(+) (blue bar) and RrrR(−) (red bar) were quantified by qRT-PCR from S. acidocaldarius MW001 recombinant strains overexpressing either RrrR(+) or RrrR(−). Relative transcript expression was normalized to the internal control gene secY. The means and standard deviation of three biological replicates are shown.