FIGURE 4.

ArgR regulates the expression of ArgG, SigB, and ArcA using arginine as a cofactor. Total bacterial cell-free protein was isolated 2 h after stress under different pH conditions (7.0 and 5.5) in the absence (A) or presence (C) of exogenous arginine (10 mM), and the protein expression levels of ArgG, SigB, and ArcA were then determined by Western blotting. GAPDH was used as an internal control. The results are indicated as of the gray scale ratio of each interest protein to GADPH (B,D). Data shown represents the Mean ± SD of two independent experiments. ^∗∗P < 0.01; ns means no significance.