Figure 3
From: Exopolysaccharide microchannels direct bacterial motility and organize multicellular behavior
Genetic analysis of M. xanthus swarm architecture. Five-microliter aliquots of cells (~108 cells) were incubated 24 h on 0.5% agar CYE to promote social motility. (a–c) M. xanthus wild-type DZ2 swarms. (d–f) Social motility-defective epsZ-. (g–i) Adventurous motility-defective cglB-. Stereomicroscopy of swarms shows the migration of (a, b) wild type across the surface in striated branches, whereas (d, e) epsZ- migrates poorly and (g, h) cglB- migrates with distinct branches. For ultrastructural analysis (c, f, i), M. xanthus swarms were fixed, stained and resin-embedded to observe ultrastructure of cell organization by sectioning and TEM visualization. Panel (c) shows the highly organized pattern of wild-type cells and microchannels, whereas panel (f) shows the lack of channels, and a corresponding lack of cell orientation in the epsZ- background, panel (i) shows cglB- with a similar organization as the wild type. The epsZ- mutant also shows that cells do not pack tightly together, with large gaps between cells. Scale bars represent 1 mm, 100 μm and 1 μm.
