Nitric oxide microprofiles measured during the dispersal assay. The y-axis shows the biofilm depth with 0 (dashed line) denoting the surface of the biofilm. Positive values are inside the spot colony biofilm and negative values are above the biofilm in the MSgg medium drop. MSgg medium was supplemented with 300 μM of the NO donor SNAP (closed symbols) or supplied without supplementation of SNAP (open symbols). Wild-type B. subtilis 3610 was incubated with a drop of MSgg (A) without further supplementation and (B) further supplemented with 100 μM NOS inhibitor L-NAME. (C) shows B. subtilis 3610 Δnos supplied with MSgg without further supplementation. Error bars depict the standard deviation (N = 10) between repeated measurements at the same position in the sample reflecting the precision of the measurement.