Project description:The leucine CUG codon was reassigned to serine in the fungal pathogen Candida albicans. To clarify the biological role of this tuneable codon ambiguity on drug resistance, we evolved C. albicans strains that were engineered to mistranslate the CUG codon at constitutively elevated levels, in the presence and absence of the antifungal drug fluconazole. Elevated levels of mistranslation resulted in the rapid acquisition of resistance to fluconazole.
Project description:Aneuploidy and the evolution of aneuploid karyotypes of Candida albicans strains was identified using aCGH. Whole chromosome and segmental aneuploidies, (specifically on the left arm of chromosome 5 - shown to be due to isochromosome formation) are associated with the appearance of resistance to the antifungal drug fluconazole. Keywords: Comparative Genomic Hybridization
Project description:Aneuploidy and the evolution of aneuploid karyotypes of Candida albicans strains was identified using aCGH. Whole chromosome and segmental aneuploidies, (specifically on the left arm of chromosome 5 - shown to be due to isochromosome formation) are associated with the appearance of resistance to the antifungal drug fluconazole. Keywords: Comparative Genomic Hybridization Hybridization of all strains was compared to the hybridization of SC5314, the sequenced laboratory strain.
Project description:Following antifungal treatment, Candida albicans, and other human pathogenic fungi can undergo microevolution, which leads to the emergence of drug resistance. However, the capacity for microevolutionary adaptation of fungi goes beyond the development of drug resistance. Here we used an experimental microevolution approach to show that one of the central pathogenicity mechanisms of C. albicans, the yeast-to-hyphae transition, can be subject to experimental evolution. The C. albicans cph1Δ/efg1Δ mutant is non-filamentous, as central signalling pathways linking environmental cues to hypha formation are disrupted. We subjected this mutant to constant selection pressure in the hostile environment of the macrophage phagosome. In a comparatively short time-frame, the mutant evolved the ability to escape macrophages by filamentation. To investigate the transcriptional response underlying the yeast-to-filament transition in the evolved strain, we applied RNA-Seq technology. Furthermore, RNA-Seq data were used to identify SNPs, which are specific for the evolved strain.
Project description:The fungal pathogen Candida albicans and other pathogens of the CTG clade reassigned the leucine CUG codon to serine and tolerate highly variable levels of both serine and leucine at CUG positions in response to environmental cues. Previous studies found that increased leucine misincorporation levels enhance resistance to drugs but the underlying mechanisms are not known. To clarify the biological role of this tuneable codon ambiguity, we evolved C. albicans strains engineered to mistranslate CUG at elevated levels, in the presence and absence of the antifungal drug fluconazole
Project description:Following antifungal treatment, Candida albicans, and other human pathogenic fungi can undergo microevolution, which leads to the emergence of drug resistance. However, the capacity for microevolutionary adaptation of fungi goes beyond the development of drug resistance. Here we used an experimental microevolution approach to show that one of the central pathogenicity mechanisms of C. albicans, the yeast-to-hyphae transition, can be subject to experimental evolution. The C. albicans cph1?/efg1? mutant is non-filamentous, as central signalling pathways linking environmental cues to hypha formation are disrupted. We subjected this mutant to constant selection pressure in the hostile environment of the macrophage phagosome. In a comparatively short time-frame, the mutant evolved the ability to escape macrophages by filamentation. To investigate the transcriptional response underlying the yeast-to-filament transition in the evolved strain, we applied RNA-Seq technology. Furthermore, RNA-Seq data were used to identify SNPs, which are specific for the evolved strain. For both strains, the cph1?/efg1? mutant and the Evo-strain, two conditions, one promotes yeast growth the other filamentous growth, were investigated. For each condition three biological replicates were analysed.
Project description:The fungal pathogen Candida albicans and other pathogens of the CTG clade reassigned the leucine CUG codon to serine and tolerate highly variable levels of both serine and leucine at CUG positions in response to environmental cues. Previous studies found that increased leucine misincorporation levels enhance resistance to drugs but the underlying mechanisms are not known. To clarify the biological role of this tuneable codon ambiguity, we evolved C. albicans strains engineered to mistranslate CUG at elevated levels, in the presence and absence of the antifungal drug fluconazole
