Daniel J. Lessner
J. William Fulbright College of Arts & Sciences
My research program is focused on the physiology, biochemistry, and genetics of the strictly anaerobic methane-producing archaea (methanogens). Methanogens are found in virtually every anaerobic environment and are the only organisms capable of biological methane production. Methane produced by methanogens is critical to the global cycling of carbon, a potent greenhouse gas, and a valuable biofuel. The pathways and enzymes involved in methanogenesis have been identified and well-characterized. However, much less is known about how methanogens respond to environmental change, including stressors. Because many methanogenesis enzymes contain oxygen-labile cofactors such as iron-sulfur clusters (1), we are particularly interested in understanding how methanogens sense and respond to oxygen and oxidative stress. We are using Methanosarcina acetivorans as a model organism, due to its metabolic diversity and robust genetic system. Two primary projects are focused on M. acetivorans proteins that contain regulatory iron-sulfur clusters. In each protein, the iron-sulfur clusters are proposed to function by modulating the structure and activity of the protein in response to oxygen or reactive oxygen species. The results obtained will provide insight into the function of iron-sulfur clusters in proteins involved in response to oxidative stress. Overall, an understanding of the oxidative stress response in methanogens will lead to better methods for modulating biological methane production, as well as providing insight into how anaerobes and archaea in general cope with oxidative stress. A third project is focused on utilizing the established M. acetivorans genetic system to develop methanogen strains with improved capabilities, including increased substrate utilization and oxygen tolerance.
Microbiology, Molecular Biology, Microbial Genetics, Microbial Physiology
BIOL3123: Prokaryote Biology
BIOL4003/5003: Laboratory in Prokaryote Biology
Ph.D. University of Iowa (Microbiology), 2003
B.S. University of Wisconsin-Stevens Point, 1996
- McCarver AC, Lessner FH, Soroeta JM, and Lessner DJ. 2016. Methanosarcina acetivorans utilizes a single NADPH-dependent thioredoxin system and contains additional thioredoxin homologs with distinct functions. Microbiology. in press.
- Jennings ME, Lessner FH, Karr EA, and Lessner DJ. 2016. The [4Fe-4S] clusters of Rpo3 are key determinants in the post Rpo3/Rpo11 heterodimer formation of RNA polymerase in Methanosarcina acetivorans. Microbiologyopen. DOI: 10.1002/mbo3.399.
- Sheehan, RC, McCarver AC, Isom CA, Karr EA, and Lessner DJ. 2015. The Methanosarcina acetivorans thioredoxin system activates DNA binding of the redox-sensitive transcriptional regulator MsvR. J. Ind. Microbiol. Biotechnol. 42:965-969.
- McCarver AC and Lessner DJ. 2014. Molecular characterization of the thioredoxin system from Methanosarcina acetivorans. FEBS Journal. 281:4598-4611.
- Jennings ME, Schaff CS, Horne AH, Lessner FH and Lessner DJ. 2013. Expression of a bacterial catalase in a strictly anaerobic methanogen significantly increases resistance to hydrogen peroxide but not oxygen. Microbiology.160:270-8.
- Isom CE, Turner JL, Lessner DJ, and Karr EA. 2013. Redox-sensitive DNA binding by homodimeric Methanosarcina acetivorans MsvR is modulated by cysteine residues. BMC Microbiol. 13:163.
- Horne AJ and Lessner DJ. 2013. Assessment of the oxidant tolerance of Methanosarcina acetivorans. FEMS Microbiol. Lett. 343(1): 13-19.
- Lessner FH, Jennings ME, Hirata A, Duin EC, and Lessner DJ. 2012. Subunit D of RNA polymerase from Methanosarcina acetivorans contains two oxygen-labile [4Fe-4S] clusters: implications for the redox-regulation of transcription. J. Biol. Chem. 287:18510-18523
- Lessner DJ, Lhu L, Wahal CS, and Ferry JG. 2010. An Engineered Methanogenic Pathway Derived from the Domains Bacteria and Archaea. MBio. 1(5):e000243-10