RipA is necessary for stability of LpxA. (A) Relative protein concentrations were determined from mid log phase cultures treated with 1.75 mg ml−1 chloramphenicol for an hour to stop protein translation. The relative abundance of LpxA protein was quantified using Image J with IglB as a loading control for equal protein from three independent experiments. Statistical significance was determined by comparing LpxA-HA adjusted relative protein values for wild type to each of the respective mutants. *, P < 0.05; **, P < 0.005. (B) Representative Western blot probed for LpxA-HA and IglB protein loaded with equal protein. (C) Transcript levels of lpxA in wild type F. tularensis and the ∆ripA strain measured by qRT-PCR. Data represent the relative transcript of lpxA normalized to gyrA from three independent experiments done in triplicate and the relative transcripts were not statistically different.