Fine structural studies of Rhodococcus species.

: Fine structural aspects of Rhodococcus rhodochrous and R. equi are described and illustrated by electron micrographs after staining of cells by a variety of electron cytochemical procedures. The cell contents of these actinomycetous bacteria were those of a typical prokaryotic cell and consistent with that observed for other species of the Actinomycetales. Fixation with either osmium tetroxide or permanganate indicated the presence of an electron opaque substance at the wall exterior of R. rhodochrous which is thought to be composed of protein. Ruthenium red and Alcian blue-lanthanum stains for mucosubstances revealed that both species possess a capsular substance thought to be composed of a mucopolysaccharide or mucopolysaccharide-protein complex. This substance was non-reactive toward the PATAg stain for polysaccharide macromolecules containing vicinal glycol groups.