FIGURE 4.

Deletion of uge5 blocks Galf synthesis and results in production of galactosaminogalactan with a reduced galactose content. A, Galf content of culture supernatants as determined by ELISA. B, galactosaminogalactan content of culture supernatants, normalized to mycelia biomass. C, galactose content of galactosaminogalactan from the indicated strains as detected by gas chromatography followed by hexose and hexosamine quantification. D, FITC-tagged GalNAc-specific soybean agglutinin (SBA) lectin binding on 12-h, Brian medium-grown hyphae of indicated strains. Total fluorescence was measured with Spectramax® fluorescence microplate reader. E, scanning electron micrograph of hyphae of indicated strains after 24 h of growth at 37 °C, 5% CO₂ in phenol-free RPMI 1640. Hyphae were fixed, sequentially dehydrated in ethanol, dried in CO₂, coated in Pd-Au, and imaged under scanning electron microscope (Hitachi). Arrows indicate surface decorations associated with galactosaminogalactan production. *, significant reduction compared with Af293 wild-type, analysis of variance with pairwise comparison p < 0.05. ±, not statistically significant compared with Af293 but statistically significant compared with the Δuge5 mutant, p < 0.05. A–C, indicated strains were grown for 72 h in Brian medium.