FIG 3.

Morphological, structural, and serological analyses of capsular components in WT and Δapt1 cells of C. neoformans. (A) Morphological aspects of the capsule in WT, apt1Δ mutant, and complemented cells were visualized by scanning electron microscopy (SEM), India ink counterstaining, and fluorescence microscopy (green fluorescence, GXM; blue fluorescence, cell wall chitin). (B) GXM was isolated from C. neoformans WT (a) or mutant (b) cells or culture supernatants (c, WT cells; d, apt1Δ mutant) and analyzed by GC-MS. The chromatographic separation of monosaccharide components revealed no differences between fractions from WT and mutant cells. (C) Determination of molecular dimensions of cellular (a) or extracellular (b) polysaccharide fractions obtained from WT and apt1Δ cells reveals polysaccharide distributions in similar size ranges. (D) Serological tests with MAb 18B7 reveal that cellular (left) and extracellular (right) GXM fractions from WT and apt1Δ cells are similarly recognized by the antibody.