Response: We thank the reviewers for giving us helpful comments.
(b) There is no clear distinction in the text between the “sheath” and the secreted “slime” of the cells, which are two completely different structures both physically and chemically (Structural and biochemical analysis of the sheath of Phormidium uncinatum. J. Bacteriol. 1998, 180, 3923– 3932). Figure 1A shows a filament that lacks the “sheath”, while in other pictures the structure is visible. The reason for this is the following: cyanobacteria of the genus Phormidium build over time a carbohydrate layer on their surface that is physically attached to their cell surface, usually called the sheath. Filaments that are ensheathed are non-motile! In contrast, the slime that is secreted by gliding filaments of the same species is not visible in TEM preparations, even when cryo-preservation methods are used (see Figure 1A of the ms and Envelope structure of four gliding filamentous cyanobacteria. J. Bacteriol. 1995, 177, 2387–2395 and Structural and biochemical analysis of the sheath of Phormidium uncinatum. J. Bacteriol. 1998, 180, 3923– 3932). Therefore, the authors should go through their ms and make a careful distinction between these two structures. For example, in the discussion it sounds as if the “sheath” is preventing the R5 cells from sliding, however this is the slime tube that is secreted that is not physically attached to the cell surface at all.