Ultrastructural architecture of colonies of different morphologies produced by phenotypic switching of a clinical strain of Candida tropicalis and biofilm formation by variant phenotypes

Phenotypic switching ofCandida tropicalisis associated with cell damage in epithelial cells and virulence inGalleria mellonellamodel

“…3,20 Although we have previously evaluated the microstructure of switched colonies of C. tropicalis, 4,21 in the present study, analysis of revertants colonies at ultrastructural level was reported for the first time. Colonies of revertants strains exhibited a smooth pattern consisting of budding yeast cells, differently to the structured morphology presented by their counterpart switched strains where filamentous growth was marked (Fig.…”

“…4,5 The isolates could switch spontaneously, heritably and reversibly between at least six different phenotypes, not including the white-opaque transition. 4,5 One of the identified switching system that include three colony phenotypes: smooth (parental phenotype) and two related switch variants (crepe and rough) was associated with in vitro changes in virulence traits, including biofilm formation, morphogenesis and hemolysis, as well as switching from itraconazole susceptibility to resistance. 5 Soll et al 6 were the first to assess switch phenotypes in C. tropicalis during the course of a prolonged Candida infection in a compromised host.…”

Scanning electron microscopy as a tool for the analysis of colony architecture produced by phenotypic switching of a human pathogenic yeastCandida tropicalis

“…It was observed as fibrils, with enlarged structures, connecting neighbouring cells. In a recent study we report the presence of extracellular material, resembling a biofilm-like colony, throughout the development of C. tropicalis switch colonies, suggesting that its presence is correlated with the complex architecture of colonies in C. tropicalis [8]. …”

“…tropicalis strains 49/07 and 335/07 included in this study were recovered from tracheal secretion and belong to the Candida culture collection of the Fungal Genetics Laboratory, The University of Londrina-Brazil. The switched variants ring and rough were obtained as previously described [8].…”

“…1D). França et al [8] were the first to describe the architecture of whole Candida colonies at ultrastructural level. Here, we extend these observations of both non-variant colonies and switch variants produced by phenotypic switching of C. tropicalis.…”