αADα Hybrids of Cryptococcus neoformans: Evidence of Same-Sex Mating in Nature and Hybrid Fitness
Figure 8
In Vitro Assays of Virulence Attributes
Serotype A (H99, Aα) and D (JEC21, Dα) reference stains and the isogenic laboratory-constructed AD hybrid (XL1462, αADα) were grown in liquid YPD medium overnight and washed three times with distilled water. Cell concentration was determined by optical density at 600 nm. Cells were then incubated on DMEM for 3 d and examined microscopically with India ink to reveal capsules (A). Three microliters of serial dilutions (10×) of cells (from overnight cultures in YPD) at the same concentration were spotted onto the indicated media for phenotypic characterization (B). Cells were grown on YPD medium at 22 °C as controls for growth (first column). Cells on YPD medium were subjected to UV irradiation for 12 s (∼48 mJ/cm2) and then incubated at 22 °C (second column). Cells were grown on YPD medium at 39 °C (third column). Cells were grown on L-DOPA medium at 22 °C (fourth column) or 37 °C (fifth column) to assay melanin pigmentation.