FIGURE 3: Chemical genetic analysis of the impact of lithium on C. neoformans. (A) Screening results for the 2008 C. neoformans knockout (CNKO) library. Results are based on OD₆₀₀ measurements and are plotted as log₂ ratio of growth in YPD medium supplemented with 100 mM lithium chloride relative to growth in YPD medium only. Roman numerals refer to the 96-well plate numbering as provided by the Fungal Genetics Stock Center (http://www.fgsc.net/). Mutants significantly affected by lithium were identified by calculating the mean log₂-ratio of growth for all mutants of an individual plate and applying a cutoff of ± 1.5-fold the standard deviation (SD). Circles represent individual mutants. Blue colored circles indicate mutants that had significantly reduced (negative log₂-ratios) or increased (positive log₂-ratios) tolerance to lithium. Grey circles indicate mutants that did not show altered growth in presence of lithium. (B) Screening results for the 2015 CNKO library. See panel A for details. (C) Screening results for the transcription factor (TF) mutant library. See panel A for details. Note that for this smaller library, the mean and ± 1.5-fold SD cutoffs were calculated for mutants of all four plates combined instead of for individual plates. The mean is indicated by a solid black line, and the dashed lines indicate the 1.5-fold SD. (D) Proportion of mutants identified from the screen with reduced or increased tolerance towards lithium.