Figure 1. . The sdh2Δ/Δ mutant is avirulent in the Caenorhabditis elegans candidiasis model and hypovirulent in the murine candidiasis model.
(A) Caenorhabditis elegans survival was followed for 144 h after Candida albicans infection (n = 60–70 worms per strain of C. albicans). Compared with the C. albicans wild-type strain SC5314, the sdh2Δ/Δ mutant is avirulent to C. elegans (p < 0.001). The reintegration of SDH2 restored the virulence of C. albicans to wild-type levels. (B) The C. elegans glp-4; sek-1 nematodes were infected by C. albicans wild-type, sdh2Δ/Δ or sdh2Δ/SDH2 strain, respectively. On day 3, the worms were photographed. (C) Mice survival was followed over 21 days (n = 12 mice per strain of C. albicans). Mice were inoculated via the tail vein with 1.5 × 106 CFUs of the indicated strains, and observed twice daily. Compared with the wild-type strain, the sdh2Δ/Δ mutant is hypovirulent (p < 0.01). (D) Fungal burden of the kidneys of mice infected with the wild-type, sdh2Δ/Δ and sdh2Δ/SDH2 reintegrated strains 2 days after inoculation (n = 4 mice per strain of C. albicans). Statistical analyses were performed using ANOVA and post hoc (Bonferroni and Student–Newman–Keuls’) tests. p < 0.05 was considered significant. *p < 0.05 compared with mice infected with the wild-type strain. (E) PAS stained thin sections of kidneys 2 days after inoculation with the indicated strains of C. albicans demonstrate differences in filamentation within the organ. Tissues were examined microscopically. Arrows indicate C. albicans filaments in the tissues.
CFU: Colony-forming unit; PAS: Periodic acid Schiff.