FIG. 4.

Impact of C. neoformans Crg2 mutation on capsule production and melanin formation. (A) Crg2 negatively regulates the production of polysaccharide capsule in vitro. Cells were inoculated in liquid DMEM medium with calcium carbonate and incubated at 30°C for 2 days. Cells were then washed, stained with India ink, and examined under a microscope (Olympus BX50) equipped with a digital camera. WT, wild type. Bars, 10 μm. (B) Crg2 exhibits no detectable role in the formation of melanin in vitro. Cells were spotted on standard Niger seed agar and placed at 30°C for 2 days. Dark pigment indicates normal melanin formation, whereas white opaque colonies indicate melanin defects.