Skip to main content
. Author manuscript; available in PMC: 2021 Mar 23.
Published in final edited form as: Curr Biol. 2020 Feb 13;30(6):1011–1022.e6. doi: 10.1016/j.cub.2020.01.073

Figure 5: Surfactin maintains viability upon oxygen depletion by depolarizing the membrane.

Figure 5:

(A) Surfactin depolarizes the membrane in B. subtilis. Membrane potential assays of strain 168 cells using the dyes DiSC3(5) (top) and ThT (bottom). The time of addition of surfactin (48 μM), valinomycin (50 μM), and CCCP (5 μM) is marked by the black arrowhead. One representative experimental replicate is shown (other replicates in Figure S6A).

(B) Treatment with the membrane depolarizing agents valinomycin (5 μM) and CCCP (5 μM) restores plating efficiency of B. subtilis strain 168 after oxygen depletion, similar to surfactin (48 μM). Error bars represent 1 SD, n=3–5. 168 plating efficiency data were significantly different than those of strain 168+surfactin, strain 168+valinomycin, strain 168+CCCP, and strain 3610 (p<0.005, Student’s t-test).

(C) Valinomycin and CCCP-treated strain 168 cultures have protoplasts, demonstrating that protoplast removal is unnecessary for viability enhancement. Overlays of phase-contrast and PI (red) images at 24 h post-oxygen depletion. Scale bar: 5 μm.

See also Figure S6.