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Rebecca Jeun

In a previous study in the Shamoo lab, a "weak link" approach was used to study evolution on the molecular scale. The necessary adenylate kinase gene (adk) in the thermophile Geobacillus stearothermophilus was replaced with its counterpart from the mesophile Bacillus subtilis. Growing G. stearothermophilus with the maladapted mesophilic adenylate kinase at an increasing temperature ramp put selective pressure on the organism. Mutations eventually arose in the gene to allow the organism to survive at higher temperatures. Current studies in the lab are expanding on the original "weak link" experiment by varying the selection pressures. My current work focuses on developing a high temperature coupled PK/LDH assay using thermostable pyruvate kinase and lactate dehydrogenase. This assay will be used to determine the activity of adenylate kinase of G. stearothermophilus to help characterize the mutations of adk that arise under the different selection regimes being studied.