Figure 1. Glass bottom culture dish used to assess plugging of septa in S. commune.

In most cases S.commune was grown in a thin layer of agar medium overlaid with minimal medium (A). However, liquid medium was not added when it was assessed whether septa were open or closed in the absence of glucose in the medium. In this case, the culture dish contained distinct patches of minimal medium with or without glucose, which were separated by a gap of 5 mm (B). (C) Magnification of boxed area in (A) and (B) showing a hypha with the first and second septum as referred to in the text.