Identifying the Genetic Underpinnings that Drive the Transition of Commensal Yeast Microbes to Opportunistic Pathogens

The unique relationship between humans and commensal microbes is a critical component of human health. Recent studies have shown that this relationship can be altered by the microbial evolution of social behaviors. Biofilms are complex microbial communities that can be found in a variety of environments. The formation of biofilms plays a vital role in driving the virulence of many microbial pathogens that are capable of infecting humans, and has allowed these organisms to survive in hostile environments. In fact, many commensal microbes have evolved into virulent, opportunistic pathogens through this mechanism. Currently, there exist a number of studies on the genetic basis underlying this transition among bacterial species in clinical settings. However, research on the evolution of virulence in medically relevant fungal species is lacking. For my research project, I intend to investigate the genetic underpinnings that result in the transition of a commensal microbe to an opportunistic pathogen by tracking the genomic changes in particular phenotypes that play a role in virulence. Specifically, I will determine whether the genetic variants uncovered in  S. cerevisiae yeast strains isolated in a clinical environment are the same genetic variants that are selected for when virulence evolves de novo in the lab.

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2 Hybrid Screen

Hello All!

I finally performed my yeast two-hyrbid screen a few days ago!

I crossed my bait, the protein E6-AP, with my prey, the human fetal brain cDNA library in it. I had to prepare a concentrated overnight culture of my bait strain. The next day, the library strain was combined with the bait strain. Then the cells were put in a shaking incubator over night. After 24 hours, I plated my mated culture. Plating the mated culture was an ordeal, because I had to pipette 100 μl of the mated culture on each plate. Mind you, I had plate fifty 150 mm plates. These plates were missing certain amino acids, in order to select for true interactions. The yeast will take 5-8 days to grow. In my last blog post, I will let you know how many colonies grew!

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