Figure 1.

Arginine uptake and utilization assays. (A) Arginine uptake. Biofilms were incubated in 75 mM arginine for treatment time indicated above before washing and collection of cell pellets for liquid chromatography–mass spectrometry targeted arginine assay. Negative controls were not incubated in arginine and were collected at the indicated time point. Error bars = SD. (B) Arginine utilization. Biofilms were incubated in 75 mM arginine for 2 h, then washed and collected at the indicated time point after arginine removal. Supernatants were analyzed with gas chromatography–mass spectrometry, and the levels of the main arginine metabolites are shown. Negative controls were collected at 6 h. Error bars = SD.