Figure 1. Comparison of cell density and measurements of four strains of Cryptococcus.

C. neoformans strains H99 and acapsular mutant cap59, and C. gattii strains WM161 and 409, were cultured overnight in Yeast Peptone Dextrose (YPD) media. Results represent at least three independent experiments per strain and condition. A) Density was evaluating using a Percoll density gradient, in comparison to a standard of density marker beads. Strain cap59 had the highest cell density (1.13 g/mL), followed by H99 (1.08–1.09 g/mL). Strains WM161 (1.06–1.085) and 409 (1.04–1.07 g/mL) had wider and less dense bands. B) Diagram of a cryptococcal cell, with cell body (red) and capsule (gray). Measurements were taken of total radius (R), cell radius (r), and capsule radius (c). The capsule volume was calculated by subtracting the volume of the cell body from the volume of the entire cell. The ratio between capsule volume and cell body volume was calculated by dividing the capsule volume by the cell body volume. C) At baseline, cell body size varied significantly between strains, with cap59 having a larger cell body and 409 having a smaller cell body. D) Baseline capsule radius was significantly larger for 409 compared to H99 and WM161. E) Strain 409 had a significantly larger baseline capsule:body volume ratio than H99 and WM161.