Electron cytochemical demonstration of the capsule of yeast-like Sporothrix schenckii.

Staining of yeast-like cells of Sporothrix schenckii by the cationic dye Alcian blue 8GX and lanthanum nitrate permitted the demonstration in thin sections of an electron opaque material localized at and along the outermost wall surface. This material was associated with the characteristic microfibrillar layer of the external cell wall. It was absent or largely removed when cells were grown in shaken liquid culture or after washing of cells from static cultures. It is believed that this loosely-bound material represents a capsular substance comprised, at least in part, of a mucopolysaccharide or a mucopolysaccharide-protein complex.