Fig. 4

Pre-incubation with Met affects AHA uptake. a, b Bs (PY79) or Bm (OS2) were grown over night in S7 medium in the presence (a) or the absence (b) of Met (50 μg/ml). Cells were then washed in PBS×1 and resuspended in S7 supplemented with AHA (1 mM). Cells were incubated for additional 2 h, underwent click reaction and visualized by fluorescence microscopy. Shown are overlay images of fluorescence from AHA (green) and phase contrast (red; left panels), and AHA fluorescence alone (right panels). c Met auxotroph Bs (LS5: ΔmetE) was grown over night with Met and processed as described in a. d A schematic model of exogenous Met effect on Bacilli Met transporters and endogenous Met synthesis. Pre growth in the presence of external Met results in AHA uptake, whereas pre-growth in the absence of external Met restricts AHA uptake. Fluorescence images were normalized to the same intensity range for each strain. Scale bars represent 3 µm