The fine structure of Chondrococcus columnaris. 3. The surface layers of Chondrococcus columnaris.

An electron microscope study of the myxobacterium Chondrococcus columnaris has revealed the following structures in the peripheral layers of the cells: (1) a plasma membrane, (2) a single dense layer (probably the mucopeptide component of the cell wall), (3) peripheral fibrils, (4) an outer membrane, and (5) a material coating the surfaces of the cells which could be stained with the dye ruthenium red.The ruthenium red-positive material is probably an acid mucopolysaccharide and may be involved in the adhesive properties of the cells. The outer membrane and plasma membrane both have the appearance of unit membranes: an electron-translucent layer sandwiched between two electron-opaque layers. The peripheral fibrils span the gap between the outer membrane and the mucopeptide layer, a distance of about 100 A, and run parallel to each other along the length of the cell. The fibrils appear to be continuous across the ends of the cells. The location of these fibrillar structures suggests that they may play a role in the gliding motility of these bacteria.