FIG. 2.

Carvs161Δ and Carvs167Δ exhibit defects in morphology. (A) Morphology of log-phase yeast-form cells grown in YPD medium plus uridine at 30°C. Calcofluor white-stained cells are shown in the top panels and DIC images in the bottom panels. The rvs161Δ and rvs167Δ cultures contained a greater level of large, round mother cells than the wild-type or complemented strains, to which a single copy of the corresponding RVS open reading frame was restored. (B) Morphology of cells grown under hyphal-inducing conditions in liquid medium (YPD plus 10% bovine calf serum for 75 min at 37°C). rvs161Δ and rvs167Δ, but not rvs162Δ, exhibited defects in hyphal growth. rvs161Δ formed predominantly pseudohyphae, while rvs167Δ produced both pseudohyphae and true hyphal filaments. However, the development of rvs167Δ filaments was slower than that of the wild-type and complemented strain filaments. (C) Defects of the rvs161Δ and rvs167Δ mutants when grown on solid-medium agar plates containing 4% bovine calf serum to stimulate invasive hyphal growth. Plates were incubated for 7 days at 37°C. The top and bottom panels show the plate before and after washing to remove the noninvasive cells. Strains used were YLD14 (rvs161Δ), YLD22 (rvs162Δ), YLD16 (rvs167Δ), YLD11 (rvs161Δ/rvs161Δ/RVS161), YLD12 (rvs167Δ/rvs167Δ/RVS167), and wild-type DIC185.