CIp20, which is a derivative of CIp10 , contains the URA3 and HIS1 markers. CIp20-GUP1 was linearized with StuI, transformed into C. albicans gup1Δ/gup1Δ to create the GUP1-reintegrant strain CF-Ca001. The integration of CIp20-GUP1 at the RPS1 locus was confirmed by PCR with primers TTGTATCACAACCCTCCC and GTGGTTGGAGCTTTGATG. The control strains were generated by transforming the parental strain (BWP17) and the homozygous C. albicans gup1Δ/gup1Δ with the empty CIp20 plasmid
linearized with StuI. Sensitivity to lipid biosynthesis inhibitors (i) Drop tests Drop tests were performed from YPD cellular young cultures suspensions, containing approximately 1 × 106 cells/ml. Ten-fold serial dilutions were made, and 5 μl of each suspension was applied on the selective media. Sapanisertib in vivo Results were scored after 3-5 days of incubation at 30°C. Selective conditions were as follow: clotrimazole (68.8 and 172 μg/ml), ketoconazole selleck inhibitor (106.3 and 265.7 μg/ml), fluconazole (30.6, 91.8 and 153 μg/ml) and fenpropimorph (60, 120 and 240 μg/ml), amphotericin B (25 μg/ml) and nystatin (2.5 μg/ml). All chemicals were obtained at the highest available grade from Sigma Aldrich. (ii) Methyl-blue diffusion test Alternatively, we assayed the sensitivity to lipid biosynthesis inhibitors with a methyl-blue-diffusion
plate test. Sterile filter disks (BBL) of 6 mm diameter were placed on top of YPD methyl-blue plates seeded with 5 ml of a wt or Cagup1Δ mutant strain young cultures. The filter disks were impregnated with 5 to 10 μl of the following drugs: clotrimazole (137.6 μg/ml), ketoconazole (212.6 μg/ml), fluconazole (91.8 μg/ml), fenpropimorph (80 μg/ml), amphotericin B (25 μg/ml) and nystatin (2.5 μg/ml). The plates were incubated at 30°C, and halos of inhibition were scored after 3 days. Again, all chemicals were obtained at the highest available grade
(Sigma-Aldrich). Filipin/Sterol fluorescence microscopy Sterol-lipid distribution was assessed in vivo using filipin. This was performed basically as described before [19, 40]. For fluorescence microscopy, cells were mounted directly on slides with a 10 μl drop of anti-fading agent Vectashield (Vector Laboratories) to Avelestat (AZD9668) overcome the instability of filipin, and immediately observed by light microscopy (LM). Colony morphology and differentiation To observe different colony morphology/differentiation, equal volumes of young cultures of each strain were diluted and spotted onto non-inducing (YPD at 30°C) and hyphal-inducing (Spider medium and on 10% FBS at 37°C) conditions, and also in YPD at 37°C. Cultures were allowed to grow for 3-5 days. Colonies on agar surface were observed under magnifying lens (10 times) and photographed. Spider medium colonies were also thoroughly observed by light microscopy.