Candida Infection Biology – fungal armoury, battlefields ... - FINSysB

Poster number: 10
The Role of Hyphae and Hypha-specific genes in the
pathogenesis of Candida dubliniensis and Candida
albicans
Peter Hyde, Derek Sullivan, Gary Moran, David Coleman.
Oral Biosciences Division, Dublin Dental School and Hospital, Trinity College Dublin, Lincoln
Place, Dublin 2, Ireland
The ability of Candida albicans to cause invasive disease has been well
documented. Candida dubliniensis, the most closely related phylogenetic neighbour
of C. albicans, causes life-threatening infections at a much lower rate,
predominantly in immunocompromised individuals. Both species can grow as true
hyphae, pseudohyphae and yeast cells. Hyphae are typically associated with host
tissue adhesion and invasion. This study aims to characterise the contribution of
general hyphal morphology, in comparison to the expression of hypha-specific cell
wall proteins, to host tissue adhesion and invasion using molecular methods and
top-down “holistic” approaches. By expressing C. albicans-specific hyphaassociated
cell wall proteins in a C. dubliniensis background under the control of a
tetracycline-inducible promoter, the ability of proteins CaALS3p, CaHWP1p, and
CaHWP1p, to cause tissue adhesion and invasion is being measured, independent
of cell morphology. In addition, by priming the C. dubliniensis mutant strains to
produce hyphae at different rates the combined effect of hypha-associated cell wall
proteins and hyphal morphology is being investigated. The ability of a panel of C.
dubliniensis strains, including systemic isolates, to produce hyphae has also been
examined and has shown high levels of inter-species variation. Interestingly, the
highest rates of true hyphae formation have been associated with strains isolated
from systemic infections, suggesting a significant contribution from the filamentous
morphology in the virulence of C. dubliniensis. This study is exploring the basis
behind the relative lack of pathogenicity of C. dubliniensis and further elaborating
on the role of hyphae and hypha-specific proteins as virulence factors in the
pathogenesis of C. albicans.
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