Chemical and ultrastructural studies on the cell walls of the yeastlike and mycelial forms of Histoplasma capsulatum

Abstract

Chemical and ultrastructural studies of the cell walls of the yeastlike (Y) and mycelial (M) forms ofHistoplasma capsulatum G-184B revealed that the Y form contained about 46.5% ofα-glucan, 31.0% ofβ-glucan, 7.7% of galactomannan and 11.5% of chitin, whereas the M form cell wall contained about 18.8% ofβ-glucan, 24.7% of galactomannan, 25.8% of chitin, and essentially noα-glucan. Theα-glucan of the Y form contained mainly anα-(1 → 3)-linkage. Theβ-glucans of both forms may have mainly aβ-(1 → 3)-linkage. Chitin microfibrils were located mainly in the inner portion of the cell walls of the Y and M forms, whereas theα-glucan fibers were observed only in the outer portion of the Y form cell wall.

Resumen

Estudios químicos y ultraestructurales de la pared celular de las formas levaduriforme (L) y micelial (M) delHistoplasma capsulatum G-184B demostraron que la forma levaduriforme contiene 46.5% deα-glucan, 31.0% deβ-glucan, 7.7% de galactomanan y 11.5% de quitina. La forma M a su vez contiene 18.8% deβ-glucan 24.7% de galactomanan, 25.8% de quitina y casi nada deα-glucan.

Elα-glucan de la forma L contiene principalmente una uniónα-(1 → 3). El-glucan de ambas formas puede tener una unionβ-(1 → 3). Las microfibrillas de quitina estan localizadas principalmente en la parte interna de la pared celular de las formas M y L mientras que las fibras deα-glucan se observan solo en la parte externa de la pared celular de la forma L.