FIG. 7.

Deletion of PKC1 causes altered capsule on capsule induction medium. (A) Strain KN99a, a strain with pkc1Δ in the KN99a background, the pkc1Δ::PKC1 strain, and the capsule-deficient cap59Δ strain in the KN99 background were streaked onto DME plates containing 1 M sorbitol and allowed to grow vertically for 5 days at 30°C in the presence of 5% CO₂. The pkc1Δ strain was shinier and runnier than the parental or the complemented strain, and the strain lacking CAP59 appeared duller and drier. (B) India ink staining of the pkc1Δ strain is abnormal compared to that of the wild type. Strains were grown on DME plus 1 M sorbitol plates for 5 days at 30°C in the presence of 5% CO₂. Individual isolates were resuspended in India ink-dH₂O at a 1:4 ratio and viewed at a magnification of ×1,000. A representative isolate for each strain is shown. (C) Strains were grown on DME plus 1 M sorbitol plates for 5 days at 30°C in the presence of 5% CO₂, and then the packed cell volume divided by total cell suspension (cryptocrit) was calculated for the KN99a, pkc1Δ, pkc1Δ::PKC1, and cap59Δ strains and shown as a percentage. All strains were analyzed in triplicate. Error bars indicate standard deviations. (D) The pellet cell volumes for each strain were calculated. These were determined from the average diameters, excluding capsule, of 50 cells each of the KN99a, pkc1Δ, pkc1Δ::PKC1, and cap59Δ strains (which were calculated to be 6.61, 4.57, 5.88, and 5.41 μm, respectively). These data suggest that although pkc1Δ cells are smaller than wild type, the increase in cryptocrit indicates that they produce more capsule than KN99a cells.