After earning a Bachelor of Arts, majoring in biology and minoring in chemistry, from the University of Louisville I joined the laboratory of Dr. Terence Marsh as a research associate in the Center for Microbial Ecology at Michigan State University (MSU). There I examined the microbiogeology of continental deep subsurface (i.e., below 200 meters) bacterial populations. A year later I began graduate studies at Arizona State University under the guidance of Dr. Ferran Garcia-Pichel and Dr. James Elser in the Life Sciences School and Dr. Jack Farmer in the Earth and Space Exploration School. While there I had the pleasure of traveling frequently to the beautiful valley of Cuatro Cienegas in Mexico to characterize calcifying cyanobacterial populations of modern microbialites (stromatolites) and those of endoevaporites. In 2003 I returned to MSU, entering the Crop and Soil Sciences Department as a graduate student where I investigated psychrophiles for a year in the laboratory of Dr. Michael Thomashow before settling in the laboratory of Dr. Richard Lenski, where I am now working toward completion of a doctorate.
Currently, I am initiating two long-term (i.e., thousands of generations) evolution experiments. One experiment involves organisms from all three Domains of life, Archaea, Bacteria, and Eukaryota, in an effort to begin elucidating evolutionary generalities that may exist among Domains and specificities that may pertain to only one or two Domains. These organisms are Haloferax volcanii, Chromohalobacter salexigens, and Dunaliella salina (a unicellular green alga), respectively. All of them are halophiles and each of them mitigate their hypersaline environment via different means. Chromohalobacter salexigens (bacterium) and Dunaliella salina (eukaryote) synthesize and intracellularly accumulate molar concentrations of organic solutes, primarily ectoine and glycerol, respectively, whereas Haloferax volcanii (archaeum) imports and intracellularly amasses molar concentrations of potassium ions. I will individually propagate each organism and I will attempt to propagate a mixed community of all three organisms or two of them. The aim of this experiment is to compare evolutionary adaptations of these organisms to environmental stressors (e.g., salinity extremes), thus illuminating evolutionary features that may be specific to one or two Domains and ones that may be generic to all Domains. Eventually, I intend to add more organisms from all three Domains to this experimental system, or start a non-halophilic multi-Domain system, to substantiate findings from this one.
The other experiment utilizes a well-studied bacterium, Escherichia coli, in an effort to understand the effects of long-term nutrient limitation on phenotypic characteristics, such as carbon : nitrogen : phosphorus stoichiometry. Using the progenitor of the ongoing E. coli long-term evolution experiment established by Dr. Lenski in 1988, I will propagate E. coli in nutritionally static and dynamic media. These media (experimental treatments) will include ones in which a single essential nutrient, carbon, nitrogen, or phosphorus, constantly or alternately limits growth. The goal of this experiment is to determine if E. coli can develop a mechanism for storing nitrogen and / or phosphorus and what effect such a possible mechanism has on its carbon : nitrogen : phosphorus stoichiometry, thus furthering insight into processes that influence the ecology and evolution of populations, communities, and ecosystems. Later, I plan to subject all of the organisms constituting the aforementioned multi-Domain experimental system to these same conditions to glimpse the diversity of responses to such nutritional regimes.
