Figure 4. pakA Strains Show Aberrant Yeast Morphogenesis at 37 °C.

The wild-type (pakA⁺), ΔpakA, ΔpakA pakA⁺, and ΔpakA pakA^H108G strains were grown in liquid BHI medium at 37 °C for 6 d. Wild type (pakA⁺) produces arthroconidiating hyphae and a mixture of fragmented and separated yeast cells. The ΔpakA pakA⁺ strains are indistinguishable from wild type. The ΔpakA mutant produces swollen arthroconidiating hyphae with increased septation. Fewer yeast cells, which are also swollen and highly septate, are produced in the ΔpakA mutant. The ΔpakA pakA^H108G strains produce swollen arthroconidiating hyphae that have reduced septation, and there are reduced numbers of yeast cells. Images were captured using DIC or with epifluorescence to observe calcofluor stained cell walls (CAL). Scale bars, 20 μm.