The impact of ORF19.36.1 in the pathobiology of Candida albicans.

BACKGROUND: Our previous proteomics data obtained from Candida albicans recovered after serial passage in a murine model of systemic infection revealed that Orf19.36.1 expression correlates with the virulence of the fungus. Therefore, the impact of ORF19.36.1 upon virulence was tested in this study. MATERIALS & METHODS: CRISPR-Cas9 technology was used to construct homozygous C. albicans orf19.36.1 null mutants and the phenotypes of these mutants examined in vitro (filamentation, invasion, adhesion, biofilm formation, hydrolase activities) and in vivo assays. RESULTS: The deletion of ORF19.36.1 did not significantly impact the phenotypes examined or the virulence of C. albicans in two infection models. CONCLUSION: These results suggest that, although Orf19.36.1 expression correlates with virulence, this protein is not essential for C. albicans pathobiology.

Serial systemic candidiasis alters Candida albicans macromorphology associated with enhancement of virulence attributes.

Candida albicans is one of the major pathogens found in superficial and invasive infections. This fungus expresses several virulence factors and fitness attributes that are essential to the pathogenesis. In our previous study using a murine model of serial systemic candidiasis, virulence of the recovered C. albicans was enhanced and several virulence factors were also modified after five successive passages through mice (P1-P5). In this study, we aimed to correlate the different fungal morphologies, as well as the filamentation, invasion, and stress resistance abilities, of the cells recovered after passing through this model of infection with our previous findings regarding virulence. We obtained two colony morphology types from the recovered cells, differing in their peripheral filamentation. The morphotype 1, which presented zero to five filaments in the colony edge, was higher in P2, while morphotype 2, which presented more than five filaments in the colony edge, was predominant from P3 to P5. In general, morphotype 1 showed similar levels regarding filamentation in serum, invasion of agar and cells, and resistance to osmotic, oxidative, and thermal stress in all passages analyzed. The morphotype 2, however, exhibited an enhancement in these abilities over the passages. We observed an accordance with the increased virulence over the passages obtained in our previous study and the increased adaptability profile of morphotype 2. Therefore, we suggest that the behavior observed previously in the pathogenesis and virulence could be attributed, at least in part, to the greater presence and ability of morphotype 2.