Description
- Abstract:
- Candida species are a group of opportunistic fungal pathogens that cause life-threatening illness in the immunocompromised, but typically inhabit the human gastrointestinal tract as a normal component of its microbiome. An essential component to their success as both a commensal and pathogen is their ability to sense and respond to environmental signals. Signaling molecules, such as pheromones, allow Candida species to communicate between one another and to orchestrate complex multicellular responses, including mating and biofilm formation. This thesis addresses several aspects of pheromone signaling and responses in two prevalent Candida species, Candida albicans and Candida tropicalis. I began with an investigation of Bar1, a secreted protease secreted that degrades α-pheromone to modulate the signaling response in C. albicans. I characterized the biochemical features of Bar1-mediated pheromone degradation and identified that Bar1 acts on a variety of Candida species pheromones, altering the sensitivity and response of C. albicans to these pheromones. Several pheromone responses in Candida species are regulated by the white-opaque phenotypic switch, a two-state system that regulates mating competence. I showed that in addition to mating, C. tropicalis responds to pheromone stimulation by forming biofilms. Surprisingly, this response was limited to cells in the mating-competent opaque state, rather than the white state, as is seen in C. albicans. My research also indicated that the master regulator of the white-opaque switch, Wor1, can also induce filamentation and biofilm formation in C. tropicalis. Finally, I examine pheromone-dependent biofilm formation in C. albicans, showing that it varies across the species and that opaque cells make a greater contribution to biofilm formation than previously appreciated. These results are discussed in relation to how they impact inter-species relationships among Candida species and with the human host.
- Notes:
- Thesis (Ph.D. -- Brown University (2015)
Access Conditions
- Rights
- In Copyright
- Restrictions on Use
- Collection is open for research.
Citation
Jones, Stephen Knox,
"PHEROMONE SIGNALING, MATING AND BIOFILM FORMATION IN CANDIDA SPECIES."
(2015).
Molecular Biology, Cell Biology, and Biochemistry Theses and Dissertations.
Brown Digital Repository. Brown University Library.
https://doi.org/10.7301/Z0NP22T6
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Molecular Biology, Cell Biology, and Biochemistry Theses and Dissertations
Theses and Dissertations for the Molecular Biology, Cell Biology, and Biochemistry department....