Culturing Pseudomonas aeruginosa Strains

Chemicals were purchased from Fisher Scientific (Waltham, MA, USA) unless otherwise stated. P. aeruginosa (PA01) was purchased from the University of Washington Genome center (Seattle, WA, USA). The PA01-derived strain with an unmarked, in-frame deletion of the bfd gene (Δbfd) had been prepared previously [16 (link)]. All strains were maintained on Pseudomonas Isolation Agar (PIA, BD Biosciences, San Jose, CA, USA). Pseudomonas aeruginosa isolation (PI) media was used to culture cells. PI media contains 20 g L⁻¹ peptone, 1.4 g L⁻¹ MgCl₂·6H₂O, 10 g L⁻¹ K₂SO₄, 25 mg L⁻¹ irgasan (Sigma-Aldrich, St. Louis, MO, USA), and 20 mL L⁻¹ glycerol, pH 7.0. PI media was supplemented with 10 µM iron using a 10 mM stock of (NH₄)₂Fe(SO₄)₂ (pH~2.0).