MALDI imaging analysis
of colony biofilms of B. subtilis NCIB3610 and
its mutants. (A,B) Single-pixel MALDI-MS spectra of
surfactins, plipastatins, subtilosin, SKF and SDP from the inner (A)
and outside (B) regions of B. subtilis NCIB3610
biofilms. (C) Selected MALDI images for B. subtilis biofilms. Each column represents (left to right): m/z 1030 (surfactin-C13, [M + Na]+); m/z 1044 (surfactin-C14, [M + Na]+); m/z 1058 (surfactin-C15, [M
+ Na]+); m/z 1485 (plipastatin-C16-Ala,
[M + Na]+); m/z 1499
(plipastatin-C17-Ala, [M + Na]+); m/z 1513 (plipastatin-C16-Val, [M + Na]+); m/z 1527 (plipastatin-C17-Val, [M + Na]+); m/z 2782 (SKF, [M + H]+); m/z 3422 (subtilosin,
[M + Na]+); m/z 4334
(SDP, [M + Na]+); and an overlay of ion images (green:
SKF; bright pink: SDP). The ion intensity is reflected by the intensity
of colors. Each column of ions is displayed using the same intensity
scale, optimized per each metabolite and normalized to the TIC. Scale
bar = 5 mm.