FIG 1.

An expanded rex regulon is necessary and sufficient for staphylococcal NO· resistance. (A) Number of putative Rex-regulated genes from closely related staphylococcal species as determined by the presence or absence of a Rex binding sites in the promoter regions. (B) Representative growth curve of three replicates demonstrating that both S. aureus and S. simiae exhibit NO· resistance compared with S. epidermidis that lacks the expanded Rex regulon. NO· was administered as a mixture of 10 mM NOC and 12:1 mM DETA-NO. (C) Overexpression of Rex from the lgt promoter limits S. aureus growth in the presence but not the absence of NO·. Representative growth curve of three independent replicates using 10 mM DETA-NO as the NO· donor. (D) Overexpression of Rex from the lgt promoter limits growth anaerobically.