Discipline: Biological Sciences
Marlene Macias - California State University Los Angeles
Co-Author(s): Natalie Rodriguez, California State University Los Angeles, Los Angeles, CA
Candida albicans is a part of the human microbiota and is found on the skin and mucosal areas of the gastrointestinal and urogenital tract. Normally this organism poses no threat in healthy individuals, but it becomes an opportunistic pathogen and cause serious superficial and systemic infections in immunocompromised individuals due to other illnesses, such as AIDS, diabetes or other diseases relating immunosuppressive therapies. As a dimorphic fungus, C. albicans is able to transition between yeast and hyphae forms. This process plays a key role in governing virulence of C. albicans and is controlled by a complex signaling network in response to its surrounding environmental conditions. This study focuses on the role of Yeast Casein Kinase 2 (YCK2) in governing cellular differentiation and cell integrity of C. albicans. YCK2 is a part of highly conserved Casein Kinase 1 family (CK1) in eukaryotic systems. CKI family has been known to govern cellular development and differentiation in higher eukaryotic system. Yet, little information is known about the function of YCK2 and its homologs (HRR25 and YCK3) in C. albicans and other fungal species. Our previous studies using YCK2 mutant strain (yck2Δ/ Δ) have demonstrated that YCK2 is crucial for the survival and proliferation of C. albicans in stressful environmental conditions. Thus we hypothesized that YCK2 is involved in stress response of C. albicans, and YCK2 is transcriptionally regulated when C. albicans is exposed to various stress condition. To test our hypothesis, the wild type C. albicans strain was exposed to various environmental stressors: Congo Red, Protamine and Pyrvinium and the transcriptional levels of YCK2, and that of its paralogs, YCK3 and HRR25 were measured using qRT-PCR. To check the morphological change in response to the stressors, DIC images of the cells grown with the stressors were compared with the cells grown with medium only. Transcriptional analysis of YCK2, HRR5 and YCK3 showed a small difference in RNA expression between the sample from medium only and samples containing stressors. Morphology of cells harvested in Congo red showed the most cell defects while the others displayed no difference against the YPD only sample leading us to conclude that the concentrations used in this experiment were too low to notice any significant changes in morphology. Additionally, a growth inhibition by pyrvinium concentrations of 2.5 microgram/ml and 5.0 microgram/ml were measured and compared to a sample grown in YPD only. Therefore, future studies will be conducted using higher concentrations of these stressors and qRT-PCR will be done to determine the optimal concentrations needed in order to notice any affect on the transcription of the CK1 family and to conclude whether or not the CK1 family of C. albicans is transcriptionally regulated by environmental stressors.
Funder Acknowledgement(s): LSAMP program, Hyunsook Park
Faculty Advisor: Hyunsook Park,