Fig. 8

An overview of the cellular responses of A. baumannii to Zn and Cu stress. Cartoon representation of A. baumannii ATCC 17978 under either high Zn (400 μM), high Cu (400 μM) or high Zn + Cu (400 μM each) conditions based on the observations from this work. The numbers within the efflux systems (ovals) are the locus-tags for A. baumannii strain ATCC 17978, excluding their prefix “A1S_”. The efflux proteins in red are those up-regulated under high Zn, in blue by high Cu and those in purple were found to be transcriptionally responsive to both high Zn and Cu independently (A1S_2939 and A1S_0709) or the combination of high Zn and high Cu (A1S_2939 and A1S_3098). Under high Zn and high Zn + Cu conditions, A. baumannii becomes increasingly sensitive to superoxide stress (O₂ ^.- in the red burst), but shows increased resistance to hydrogen peroxide (green cloud). Under high Cu conditions, A. baumannii shows increased susceptibility to hydrogen peroxide (H₂O₂ in the red burst). Under high Zn conditions and high Zn + Cu conditions, Cu levels reduce to 74 and 62%, respectively