Fig 6.

(A) Magnetic response (C_mag) of WT and ΔnirS mutant after three serial transfers under microaerobic conditions in iron-deprived medium. Nonmagnetic WT and the ΔnirS mutant were induced anaerobically for 6 h in the presence of reduced (100 μM ferrous chloride plus 0.2 mM ascorbate) and oxidized (100 μM ferric chloride) iron sources. (B) Growth (based on the OD₅₆₅) and magnetic response (C_mag) of WT, ΔnirS, ΔnirN, and Δnap strains in an incubator hood with a constant atmosphere of 2% O₂ and 98% N₂. (C) Intracellular localization of the MSR-1 NirS protein N-terminally tagged with mCherry in the ΔnirS mutant. Differential interference contrast microscopy (left) and fluorescence microscopy (right) were used. Bar, 2 μm. (D) TEM images of the anaerobically grown ΔnirS mutant carrying nirS (top to bottom) from M. magneticum (amb1395, amb4165) and P. stutzeri (PST_3532), respectively. Bar, 500 nm.