Figure 1. Membrane assemblies in vegetative hyphae.

(a) In vegetative hyphae of S. coelicolor M145 stained with the membrane dye FM5–95 (red) and the cell wall dye FITC-WGA (green), cross-walls are evident (arrowheads). (b) Large membrane structures/agglomerates are also found within hyphae, which do not co-localize with WGA-stained cross-walls (arrowheads). (c–f) To investigate their ultrastructure, membranes in S. albus were fluorescently labelled with FM5–95 and imaged with cryo-CLEM. Positions with extended lipids were observed (d–f). Cross-membrane assemblies within hyphae (d,e) and at tips (e,f) consisted of extended tubular membrane structures. A light region, devoid of ribosomes and other macromolecular complexes, can be seen forming a faint ribbon behind a membrane-filled tip (arrows, f; for tomogram see Supplementary Movie 1). Scale bars, 5 μm (a–c), 500 nm (d–f).