TBI Seminar: Dr. James Hemp, University of Utah
- Monday, April 15, 2019 from 3:10pm to 4:00pm
- Plant Biosciences Building, 108 - view map
Dr. James Hemp will present “Diversity and evolution of high potential metabolisms: Photosynthesis, aerobic respiration, and nitrogen cycling,” at TBI seminar. Dr. Hemp received his PhD in biophysics and computational biology from the University of Illinois at Urbana-Champaign. He was an Agouron Postdoctoral Scholar at the California Institute of Technology in the Division of Geological and Planetary Sciences. He is currently a scientist at the University of Utah. Dr. Hemp's research is focused on the interface of microbial biochemistry, physiology, ecology, and evolution. He is currently working on the role of molecular oxygen in Earth's history and the evolution of biogeochemical cycles.
Abstract: High redox potential metabolisms (chlorophyll-based photosynthesis, aerobic respiration, denitrification, nitrification, and ANAMMOX) structure modern ecosystems and have played critical roles in the evolution of Earths biogeochemical cycles. The electron transfer chains of these processes share a common core architecture composed of a small number of evolutionarily related protein families. Evolutionary analyses of these proteins can be used to ordinate the origin of these metabolisms, providing key insights into major transitions in Earth history.
I will discuss recent work investigating the evolution of oxygenic photosynthesis and how microbial metabolisms adapted to the presence of oxygen. Oxygenic photosynthesis evolved from anoxygenic ancestors sometime in the Archean, however little is known about the mechanism and timing of its origin. Recently discovered non-phototrophic Cyanobacteria provide new insights into this transition, suggesting that oxygenic photosynthesis evolved from Mn2+ oxidizing phototrophs around the time of the great oxygenation event (GOE) 2.35 billion years ago. I will discuss the origin and evolution of high potential respiration. The heme-copper oxidoreductase (HCO) superfamily is extremely diverse, with members playing crucial roles in both aerobic and anaerobic respiration. I describe five previously uncharacterized HCO families that perform nitric oxide reduction. These newly identified nitric oxide reductases exhibit broad phylogenetic and environmental distributions, expanding the diversity of microbes that can perform denitrification. Phylogenetic analyses of the HCO superfamily demonstrate that nitric oxide reductases evolved multiple times independently from oxygen reductases, suggesting that denitrification evolved after aerobic respiration.
Host: Dr. Roland Hatzenpichler
If you would like to meet with Dr. Hemp, please contact Roland Hatzenpichler at firstname.lastname@example.org