FIG 3.

R. mucilaginosa strains do not produce capsules as large as those of C. neoformans under standard capsule-inducing conditions. Sixteen growth conditions are shown for the following three example strains: H99 C. neoformans, ARY 115 environmental R. mucilaginosa, and ARY 201 clinical R. mucilaginosa. Equivalent numbers of cells were introduced to wells containing PBS, DMEM, Sabouraud (Sab), or 10% diluted Sabouraud media (as indicated), with or without CO₂ and with or without 10% FCS, and incubated for 1 week at 37°C. The experiments performed under the indicated CO₂ conditions were performed at the same time for all strains. Samples of each well were mixed with India ink and visualized. While the DMEM and 10% Sabouraud conditions appeared to produce the largest capsules for H99, the R. mucilaginosa capsules were not nearly as large under any of the conditions. Bar, 10 μM. All images were taken at the same resolution and prepared in the same manner.