FIGURE 4.

Vad1 mutation enhances filamentation. MATα wild type (H99) and Δvad1 strains were co-cultured (A) or confronted (C) with the MATa wild type (KN99) strain on V8 medium and incubated for 7 days at room temperature in the dark. Representative edges of the mating patches were photographed at ×40 magnification. B, filamentous hyphae from KN99XΔvad1 were fixed and stained with calcofluor white (CFW) and propidium iodide (PI), demonstrating clamp junctions (arrows), and DNA (red). Bar, 10 μm. D, the indicated strains were co-cultured with KN99 on V8 medium and incubated for 4 days at room temperature in the dark. E, analysis of virulence of MFα overexpressed in wild type strain compared with the wild type with empty vector alone using a mouse model of disseminated cryptococcosis with an intravenous inoculum of 1 × 10⁵ yeast cells (10 mice/group; p < 0.005).