albicans DAY286 cells exposed to 30 μM or 1.2 μM FeCl3 in YNB medium for 0, 5, 10 or 20 min at 30°C. Procedures were the same as indicated above except the following: 16 μg protein per sample were loaded on the gel and the membrane was exposed for 20 sec (P-Hog1p) and 30 sec (Hog1p) respectively. The pictures were slightly rotated to obtain almost straight bands. Hog1p was required for maintenance of C. albicans viability under high iron conditions Since Hog1p appeared to be involved in the response of C.

albicans to high iron concentrations, we investigated whether Hog1p could have any protecting effect on C. albicans against deleterious effects of https://www.selleckchem.com/products/byl719.html exposure to high iron levels. Thus, we determined the viability of cells after exposure to 30 μM Fe3+ using the AlamarBlue® assay, which is an indicator of the metabolic activity of cells [46]. This fluorescence

assay has been widely used to determine viability of different yeasts including YM155 datasheet C. albicans[47–49]. We observed that basal fluorescence signals were always higher for Δhog1 cells than for the reference strain DAY286 (data not shown). This could be due to the intrinsically enhanced mitochondrial activity of HOG1 deficient cells [36]. Cells were exposed to 30 μM FeCl3 in RPMI and incubated at 30°C for 60 min. A decrease of the reduction rate of AlamarBlue®, i.e. of the viability, was observed for all tested strains. However, exposure to high iron levels led to a higher decrease of the signals obtained from the Δhog1 mutant (residual viability 46 ± 3%) compared to the reference strain (DAY286) (residual viability Janus kinase (JAK) 81 ± 9.5%) and the wild type (SC5314) (residual viability 85%). These data indicate that the Δhog1 mutant was less resistant to high iron levels than the WT cells. However, after

2 days no apparent growth defects were observed when the PRI-724 concentration strains SC5314 (WT), DAY286 (reference strain), Δhog1 and Δpbs2 were grown on RPMI agar supplemented with 30 μM FeCl3 compared to cells grown on the same medium containing 0 or 1 μM FeCl3, respectively (see Additional file 6). This would indicate that the reduced metabolic activity of the Δhog1 mutant under high iron conditions did not affect growth of C. albicans on the long term. The lower reduction rate of AlamarBlue® after exposure of Δhog1 to high Fe3+ concentrations was probably not due to the more oxidized intracellular environment after exposure of Δhog1 cells to high iron concentrations, as Δhog1 cells had a higher basal ROS level than WT cells, but the basal AlamarBlue® signals were also higher. Thus, the intracellular oxidation state (indicated by the ROS level) did not directly correlate with AlamarBlue® signals. Discussion Previous studies on Δhog1 mutants from C. albicans and Cryptococcus neoformans showed that deletion of HOG1 led to the de-repression of several genes known to be upregulated under restricted iron conditions [27, 50]. In C. albicans, this group of genes included RBT5, FRE10, FTR1, FET34, orf19.