Fig 1. C. albicans FLP genes are needed for resistance to oxidative stress.

(A) Structures of oxidized benzoquinone, reduced benzoquinol, and the semiquinone intermediate that is a reactive oxygen species. Two-electron reduction of quinones avoids creation of the semiquinone intermediate. (B) Serial 10-fold dilutions of cells were spotted onto synthetic medium agar plates containing the indicated chemical and then incubated at 37°C for 48 h. Quinones tested included BZQ (p-benzoquinone) and MND (menadione). Oxidants included H₂O₂, as well as more hydrophobic peroxides that target the membrane: TBHP (tert-butyl hydroperoxide) and CHP (cumene hydroperoxide). In addition, monounsaturated OA (oleic acid) was used as a control for the polyunsaturated LNA (linolenic acid), which is known to induce lipid peroxidation. Strains used were the wild type strain LLF100, Δ/Δ/Δ/Δ strain LLF060 (pst1Δ pst2Δ pst3Δ ycp4Δ), and the complemented strain LLF079 in which one copy of each FLP gene was introduced into the Δ/Δ/Δ/Δ strain (pst1Δ pst2Δ pst3Δ ycp4Δ PST1 PST2 PST3 YCP4).