qRT-PCR analysis of psdR expression levels in casamino acids medium and casein broth.

(A-B)The wild-type strain PAO1(WT),the PsdR-null mutant (ΔpsdR) and the PsdR-expressing strain (ΔpsdR::PrrnB::psdR) were grown in casamino acids medium or casein broth for 24 h at 37°C. Total RNA of each strain was then extracted for qRT-PCR analysis. Relative expression was normalized using proC gene data. Data are means ± SD (3 independent RNA extractions; n ≧ 5). P-values were obtained from t-tests. *P < 0.05, **P < 0.01, ***P < 0.001 (t-test).

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