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

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.