Figure 7.

Kennedy pathway is active, and PS is essential in C. neoformans. A, cultures of S. cerevisiae WT strain BY4742, C. neoformans WT strain H99, and its Cn cki1Δ (predicted Sc CKI1 homolog) were cultured in SC medium with supplement of 10 μCi [¹⁴C]ethanolamine or [¹⁴C]choline. The production of PE and PC was detected by the radioactive signal in the 1D-TLC analysis. Purified PE and PC standards were purchased from Avanti Lipids. Positions of PE and PC were determined using iodine staining. 1D-TLC assay was repeated multiple times with identical results. B, lyso-PS rescued the growth arrest of P_CTR4-CHO1 strain under inhibitory conditions. H99 and P_CTR4-CHO1 strains were cultured in SC medium containing 1 mm CuSO₄ and 1% Nonidet P-40, in the presence or absence of 50 μm lyso-PE or lyso-PS for 60 h at 30 °C with shaking. Growth rate was determined by A_{600 nm} at different time points. Each growth assay was done in a triplicate and repeated at least twice.