Cellular morphology of the hyphal form of the C. albicans sur7 Δ null mutant strain. (A) Filamentation was assessed in RPMI-1640 medium. Medium was inoculated with 5 × 106 cells ml-1 and incubated at 37°C for 24 h with constant shaking at 200 rpm. Standard light microscopy with a 40× objective was used to visualize the morphology of the filaments formed by wild-type (WT) and sur7 Δ homozygous null mutant (sur7 Δ) strains. (B) Thin-section electron micrographs of wild-type and sur7 Δ hyphal cells are shown with arrows indicating abnormal structures similar to that seen in the yeast form of the sur7 Δ null mutant (Fig. 7B). A size bar is shown to indicate 500 nm.