FIGURE 4.

Effects of various antimicrobial agents on the peptidoglycan of B. anthracis ftsE(K123A/D481N). B. anthracis ftsE(K123A/D481N) strain was treated with (A) buffer control, (B) penicillin (35 μg/ml), (C) CXCL10 (2.8 μM), or (D) CTTC (2.8 μM) to determine the effect on existing peptidoglycan integrity (EDA + Alexa Fluor 488 green fluorescence) and new subunit incorporation (TDL red fluorescence). Vegetative cells were incubated with EDA for 1 h before the addition of an antimicrobial agent (or buffer control) concurrently with TDL for 1 h, followed by a “Click-iT” reaction to bind Alexa Fluor 488 to EDA, as described in Section “Materials and Methods.” Scale bar is 5 μm. n = 2 separate experiments with 5–20 images being acquired for each treatment group. Relative fluorescence intensity was determined as a percentage of the untreated control sample of the same strain.