Fig. 2.

α-(1,3)-Glucan comprises the outer cell wall layer of yeast. Wild-type Histoplasma yeasts were fixed, and antibodies specific for α-(1,3)-glucan (A) and β-(1,3)-glucan (B) were used to localize the respective polysaccharides. (C) Merged α-(1,3)-glucan and β-(1,3)-glucan localizations show a somewhat layered spatial organization. (D) Tracings of the α-(1,3)- and β-(1,3)-glucan outer perimeters (red and green, respectively) were overlaid, confirming that α-(1,3)-glucan forms the outermost surface. (E) Representative immunoelectron micrograph (n = 25) in which α-(1,3)-glucans and β-glucans were labeled in wild-type yeast cells with 18-nm and 12-nm gold particles, respectively. (F and G) Histograms showing the distribution of individual α-(1,3)-glucan (F; n = 342) and β-(1,3)-glucan (G; n = 162) labeling in electron micrographs, calculated as the perpendicular distance from the cell membrane.