Rhodomyrtone causes membrane invaginations.

(A) Delocalization of AtpA-GFP. (B) SIM images of B. subtilis 168 cells stained with mitotracker green (MTG) treated with 1x MIC rhodomyrtone for 10 min (lower panel, untreated cells in the upper panel). (C) SIM images of B. subtilis strain bSS82 expressing cytosolic GFP from the strong ribosomal PrpsD promoter stained with Nile red. Upper panels show untreated cells, lower panels show cells treated with 1x MIC rhodomyrtone for 10 min. The absence of a green fluorescence signal indicates the presence of large membrane invaginations (yellow arrows). Blue arrows indicate small membrane invaginations. (D) SIM images of B. subtilis 168 stained with DiIC12. Note that DiIC12 clearly stains rhodomyrtone-induced membrane invaginations (yellow arrows). Native RIFs only appear as small foci of increased fluorescence (green arrows), but not as invaginations or intense patches in untreated cells. Scale bars 2 μm. (E) TEM pictures of B. subtilis 168 treated with 1x MIC rhodomyrtone for 10 min. (i) Untreated control cell, (ii) representative cell treated with rhodomyrtone. Yellow arrow indicates a large intracellular membrane vesicle structures, blue arrows indicate small membrane vesicles. (iii-vi) Details of cells treated with rhodomyrtone. Membrane vesicles and/or invaginations occurred in all longitudinally cut cells that were observed in the rhodomyrtone-treated samples, while the untreated cells that we observed never showed these deformations (n ≥ 20). Scale bars 0.5 μm.