Fig 3.
Ergosterol quantification in C. albicans laboratory strains expressing mutant UPC2 alleles. Increased ergosterol content was shown for strains expressing 2 UPC2 mutant alleles compared to the expression levels in heterozygote and wild-type strains. The heptane extraction layer from 16-h cultures was scanned spectrophotometrically between 240 and 300 nm. The presence of ergosterol in an extracted sample resulted in a 4-peak curve. A decrease in absorbance peaks correlates to a decrease in ergosterol content. Each panel represents the results for a different Upc2 GOF mutation, as follows: G648S (A), A643V (B), Y642F (C), G648D (D), A646V (E), A643T (F), W478C (G), and G304R (H). UPC2 mutant alleles were expressed as homozygotes with the same GOF mutation (○) or as heterozygotes with the wild-type allele (▲). Their absorbencies were compared to those of the wild-type strain SC5314 (●). The results for the homozygous revertants shown in panels C, D, and G showed statistically significant greater ergosterol contents than were found in the wild type (P < 0.05).