FIG 7.

De novo sphingolipid biosynthesis is required for C. albicans filamentation. (A) C. albicans WT filamentation is inhibited by myriocin (Myr) on solid, hypha-inducing medium and partially restored by additional supplementation of phytosphingosine (Phy). SD log-phase cells were spotted on the solid medium and incubated in either the absence (WT) or the presence of 0.25 μM myriocin (WT_Myr) in the preculture. Notably, solidified HS did not induce filamentation and was therefore excluded. (B) C. albicans WT filamentation in liquid, hypha-inducing medium with the indicated supplementation of Myr and Phy after 240 min. (C) SD log-phase cells of the WT, incubated in either the absence (WT) or the presence of 0.25 μM myriocin (WT_Myr) in the preculture, were transferred to liquid, hypha-inducing medium. Examination of the filamentation after 90 min revealed a hyperfilamentous phenotype for myriocin-pretreated cells (WT_Myr). Filamentation score: 0, yeast; +, germ tubes and small hyphae; ++, moderate filamentation; +++, extensive filamentation; +, isolated germ tubes. Bar, 100 μm.