Journal: bioRxiv
Article Title: Peroxisomes regulate virulence and cell density sensing in Cryptococcus neoformans
doi: 10.1101/2025.05.14.654083
Figure Lengend Snippet: (A) Peroxisomal β-oxidation pathway of Saccharomyces cerevisiae with C. neoformans homologs (CNAGs). Created with BioRender. (B) mfe2 Δ and pot1 Δ were sensitive to the oxidative stress inducer Diethyl Maleate (DEM). Strains mfe2 Δ and pot1 Δ were sensitive to nickel exposure while pox1 Δ had high nickel tolerance, which was especially apparent at 5 mM. 1:3 serial dilutions were spotted on minimal media agar containing either DEM (2mM) or nickel and imaged after 48 h of growth at 30°C. pox1 Δ had high nickel tolerance, which was especially apparent at 5 mM. (C) Susceptibility to fluconazole exposure. At 8 μg/mL, mfe2 Δ and pot1 Δ displayed similar fluconazole tolerance to WT at higher cell density spots and reduced tolerance in lower cell density spots. At 24 μg/mL of fluconazole, only pox1 Δ was tolerant. The colony photographs throughout the paper were taken under the same illumination and consequently some colonies appear to show very similar or identical light reflections that manifest as white dots, arcs, and other light effects. However, these photographs were each individually taken and were not spliced or combined, thus represent different sets of colonies grown under different conditions. D) Representative India ink images after 7 d in minimal media without L-DOPA (40x magnification, scale bar = 10 μm). Measurements of cell diameter (capsule + cell body), cell body diameter, and capsule radial thickness. Compared to WT, the mfe2 Δ and pot1 Δ strains had significantly smaller cell body sizes and capsule radial thickness (n= 3 biological replicates, ∼25 cells measured and pooled between biological replicates, One-way ANOVA ****, p-value <0.0001). E) Urease halo size (n = 3 biological replicates after 48 h). mfe2 Δ had a severe urease defect compared to WT (One-way ANOVA, p-value <0.0001), and pot1 Δ produced urease halos with ∼3-times the standard deviation of WT (WT: Mean=6.998 SD=0.4988, mfe2 Δ: Mean= 1.716 SD=0.2490, pot1 Δ: Mean=5.914 SD=1.406). F) Mean grey value of melanization cultures showed highly variable growth and melanization for both mfe2 Δ and pot1 Δ (n=4 biological replicates, WT: Mean=28.35, SD= 3.940, mfe2 Δ: Mean=52.24 SD= 24.59, pot1 Δ: Mean=67.52 SD=40.16). G) Low starting inoculum (1 x 10 4 cells/mL) arrests overnight growth of mfe2 Δ and pot1 Δ, resulting in reduced CFUs. H) Starting inoculum differed between serial dilution experiments in panels B & C (1 x 10 7 cells/mL) and panel G (1 x 10 4 cells/mL). Decreasing the starting inoculum markedly reduced the number of CFUs of both mutants compared to WT.
Article Snippet: Fluconazole (FLC) (MilliporeSigma) was added directly to cooled agar, and plates were used immediately.
Techniques: Produced, Standard Deviation, Serial Dilution
