%0 Journal Article %A Springer, E. Louise %A Roth, I. L. %T The Ultrastructure of the Capsules of Diplococcus pneumoniae and Klebsiella pneumoniae Stained with Ruthenium Red %D 1973 %J Microbiology, %V 74 %N 1 %P 21-31 %@ 1465-2080 %R https://doi.org/10.1099/00221287-74-1-21 %I Microbiology Society, %X SUMMARY: Capsules of Diplococcus pneumoniae type III and Klebsiella pneumoniae type I were examined in the electron microscope using ruthenium red in combination with osmium tetroxide. The ability of this combination stain and fixative to stain polysaccharides has been well established. A slightly acid pH was necessary to obtain satisfactory capsular polysaccharide staining. The capsules of both Diplococcus pneumoniae and Klebsiella pneumoniae were stained by the ruthenium red before alcohol dehydration and embedding in Epon 812. The capsule of D. pneumoniae had the appearance of a tightly woven mat. The capsule of K. pneumoniae had a fibrous appearance. Ruthenium red was found inside the plasma membrane of D. pneumoniae, but remained outside the cell membrane of K. pneumoniae. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-74-1-21