Fields Lab Group
The physiology and ecology lab is interested in “environmental” organisms and biofilms involved in a variety of processes that include nitrate contamination, heavy metal reduction, metal corrosion, extremophiles, and bio-energy. Our work is focused on the relationships between biotic and abiotic factors that mediate control over physiology and modes of growth, and how signals are sensed and cells respond accordingly in order to optimize metabolism. We study both monocultures and indigenous microbial communities to better understand the interrelationships between genomic content and phenotype at different levels of resolution (i.e., DNA to community), and how these attributes contribute to stress and survival of biological cells.
Current Projects Related to TBI
· Genome Project – Alkaliphilus metalliredigens
Alkaliphilus metalliredigens can reduce Fe(III)-citrate, Fe(III)-EDTA, Co(III)-EDTA, or Cr(VI) as electron acceptors with yeast extract or lactate as electron donors. Growth during iron reduction occurs over the pH range of 7.5 to 11.0, a sodium chloride range of 0 to 80 g/l and a temperature range of 4°C to 45°C. Optimal growth conditions during iron reduction in the presence of borate (2 g/l) were observed at a pH of 9.6, a sodium chloride concentration of 20 g/l and a temperature of approximately 35°C. A. metalliredigens is a strict anaerobe that can tolerate up to 1.5% (w/v) borax (Na2B4O7), and the cells are straight rods that produce endospores. The microorganism appears to be a novel metal-reducing bacterium that is distantly related to other commonly studied iron-reducing microorganisms. At the present time, the most closely related microorganisms are Alkaliphilus transvaalensis and Alkaliphilus crotonatoxidans.
· Genome Project – Thermoanaerobacter pseudoethanolicus X514 and 39E
Thermoanaerobacter pseudoethanolicus isolates can use lactate, acetate, succinate, xylose, and glucose as electron donors during the reduction of Fe(III) oxyhydroxide. Although these isolates are closely related in phylogeny, they showed some physiological differences. Strain X514 can utilize both pyruvate and hydrogen when reducing Fe(III) oxyhydroxide and producing magnetite. Both strains can produce ethanol during fermentation of pentoses and hexoses.
· Microbial Community Dynamics at Thermoalkaline Springs
We have initiated studies to characterize microbial community dynamics along temperature and pH gradients in alkaline springs in Yellowstone. We would like to determine the realtinships between biotic and abiotic parameters in these unique systems, as well as identify and isolate microorganisms of interest.
Current Laboratory Personnel
Dr. Andrew Sabalowsky, Postdoctoral Researcher
Chiachi Hwang, Ph.D. Student
Anitha Sundararajan, Ph.D. Student
Kristen Brileya, Ph.D. Student
Kara De Leon, Ph.D. Student
Kelly Oshea, Ph.D. Student
Brad Ramsay, Res. Associate
Erik Beil, Undergraduate Student
Elliott Barnhart, Undergraduate Student
Philip Gardner, Undergraduate Student