Photograph of strains cultured in casein broth.

Photograph of indicated strains grown in casein broth. Strains cultured overnight in LB-MOPS medium were diluted into OD₆₀₀ ≈ 0.02 and subsequently inoculated into casein broth for culturing at 37°C. Photograph was taken after 24 h inoculation. WT, wild-type strain PAO1; ΔpsdR, PsdR-null mutant; ΔpsdRΔmdpAΔdppA3, triple gene deletion mutant; ΔpsdR::PrrnB::psdR, PsdR-null mutant carrying a single copy of psdR driven by a rrnB promoter.

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