Teresa Thiel

Research Interests (nitrogen fixation, cyanobacteria, molybdenum transport, gene regulation, hydrogen production)

My research is in the area of microbiology and molecular biology, specifically on nitrogen fixation and gene regulation in filamentous cyanobacteria. We are interested in three sets of genes that encode the proteins requires for three independent nitrogenases that convert atmospheric nitrogen to ammonia. These genes are independently regulated by environmental conditions including the availability of metals such as molybdenum and vanadium or the anoxic or oxic state of the cells. We are interested in the molecular mechanisms that control the differential expression of the three sets of genes. One mechanism of control of these genes is the metal molybdenum. We are interested in the transport of molybdenum in cyanobacteria and how it regulates expression of nitrogenase genes.

The enzyme nitrogenase also produces hydrogen gas; thus, potentially providing a renewable source of energy. We are investigating the feasibility of genetically modifying cyanobacteria for the commercial production of hydrogen gas for fuel cells that can be used to power automobiles in the future.
 

In situ expression of nif1 and nif2. (A and B) Strain TT216 (nif1::lacZ fusion) was induced aerobically for 24 hr as described in Thiel et al. (1995) prior to incubation with C12-FDG. A and B differ only in that filaments in B were photographed with a 560-nm shortpass filter to block the red fluorescence of the biliproteins. (C and D) Strain TT216 was induced anaerobically for 24 hr as above; same filament without (C) and with (D) a 560-nm filter. (E and F) Strain JE35 (nif2::lacZ fusion) was induced anaerobically for 6 hr (E) or 24 hr (F) prior to incubation with C12-FDG. Both photographs were taken with a 560-nm filter. White arrows indicate heterocysts identified from light micrographs. (Bars = 10um)  Thiel, T., Lyons, E. M., Erker, J. C. and A. Ernst. A second nitrogenase in vegetative cells of a heterocyst-forming cyanobacterium. Proc. Natl. Acad. Sci. U.S.A. 92:9358-9362. (1995). (pdf file)

Recent Publications

Thiel, T., and Pratte, B., 2006. High-affinity vanadate transport system in the cyanobacterium Anabaena variabilis ATCC 29413. J. Bacteriol. 188:464-468. (pdf file)

Thiel, T. 2006. Nitrogenase, Hydrogenase and Hydrogen Production by Cyanobacteria. In: Singh, S. (ed). Micro-algal Biotechnology. Pvt.Ltd, New Delhi,India. (pdf file)

Thiel, T., Whiteman, N.K. Tirapé, A., Ines-Baquero, M., Cedeño, V., Walsh, T, Jiménez-Uzcátegui, G. and Parker, P.G. 2005. Characterization of Canarypox-like Viruses Infecting Endemic Birds in the Galápagos Islands.  J. Wildl. Dis. 41:342-353.

Thiel, T. 2004. Nitrogen Fixation in Heterocyst-Forming Cyanobacteria. 2004. pp. 73-110. Chapter 5. In: W. Klipp, B. Masepohl, J.R. Gallon & W.E. Newton (eds.), Genetics andRegulation of Nitrogen Fixing Bacteria. Kluwer Academic Publishers, Printed in the Netherlands.

Zahalak, M., Pratte, B., Werth, K.J., and Thiel, T. 2004. Molybdate transport and its effect on nitrogen utilization in the cyanobacterium Anabaena variabilis ATCC 29413. Molec. Microbiol. 51: 539-550. (pdf file)

Thiel T, Pratte B, Zahalak M. Transport of molybdate in the cyanobacterium Anabaena variabilis ATCC 29413. Arch Microbiol. 179:50-56 (2002). (pdf file)

Meeks. J. C., Elhai, J., Thiel, T., Potts, M., Larimer, F, Lamerdin, J., Predki, P. and R. Atlas. An overview of the genome of Nostoc punctiforme, a multicellular, symbiotic cyanobacterium. Photosynthesis Research. 70:85-106 (2002). (pdf file)

Thiel, T., Meeks, J.C, Elhai, J., Potts, M., Larimer, F., Lamerdin, J., Predki, P., and R. Atlas. Nitrogen Fixation: analysis of the genome of the Nostoc punctiforme. in: Nitrogen Fixation: Global Perspectives. Edited by Finan, T.M, O'Brian, M.R., Layzell, D.B., Vessey, J.K, and Newton, W. CABI Publishing. New York. pp. 88-92. (2002).(pdf file)

Thiel, T. and B. Pratte. Effect on heterocyst differentiation of nitrogen fixation in vegetative cells of the cyanobacterium Anabaena variabilis ATCC 29413. J. Bacteriol. 183: 280-286. (2001). (pdf file)

Thiel, T. Genetics and regulation of multiple nitrogenases in the cyanobacterium Anabaena variabilis ATCC 29413. pp. 1-27. In: Cyanobacterial and Algal Metabolism and Environmental Biotechnology. Edited by T. Fatma. Phycological Society. India. (1999).

Thiel, T., Liczkowski, L., and S.T. Bissen. New zwitterionic butanesulfonic acids that extend the alkaline range of four families of Good buffers: evaluation for use in biological systems. J. Biochem. Biophys. Meth. 37: 117-129. (1998).

Thiel, T., Lyons, E.M., and Thielemier, J. Organization and regulation of two clusters of nif genes in the cyanobacterium Anabaena variabilis. pp. 517-521. In: Phototrophic Prokaryotes. Edited by G.A. Peschek, W. Loeffelhardt, and G. Schmetterer. Plenum Press, N.Y. (1998).

Heinlein, M., Wood, M.R., Thiel, T., and R.N. Beachy. Targeting and modification of prokaryotic cell-cell junctions by tobacco mosaic virus cell-to-cell movement protein. Plant J. 14: 345-351. (1998). (pdf file)

Thiel, T., Lyons, E.M. and J.C. Erker. Characterization of genes for a second Mo-dependent nitrogenase in the cyanobacterium Anabaena variabilis. J. Bacteriol. 179:5222-5225. (1997). (pdf file)

Thiel, T., Lyons, M., and M. Zahalak. Regulation of alternative nitrogenase systems by environmental factors in the cyanobacterium Anabaena variabilis. In Bothe, H. (ed.) Biological Fixation of Nitrogen for Ecology and Sustainable Agriculture. NATO ASI ser. G.Springer Verlag. pp. 159-162. (1997).

Thiel, T. Isolation and characterization of the vnfEN genes of the cyanobacterium Anabaena variabilis. J. Bacteriol.178:4493-4499 (1996). (pdf file)

Thiel, T., Lyons, E. M., Erker, J. C. and A. Ernst. A second nitrogenase in vegetative cells of a heterocyst-forming cyanobacterium. Proc. Natl. Acad. Sci. U.S.A. 92:9358-9362. (1995). (pdf file)

Zahalak, M., Beachy, R.N., and T. Thiel. Expression of the movement protein of tobacco mosaic virus in the cyanobacterium Anabaena sp. PCC 7120. Molecular Plant Microbe Interactions. 8:192-199 (1995).

Lyons, E. and T. Thiel. Characterization of nifB, nifS, and nifU mutants of the cyanobacterium Anabaena variabilis: NifB is required for the V-dependent nitrogenase. J. Bacteriol. 177:1570-1575. (1995). (pdf file)

Thiel, T. Genetic analysis of cyanobacteria. In: Bryant, D.A. (Ed.) The Molecular Biology of the Cyanobacteria. Kluwer AcademicPress. Dordrecht, The Netherlands pp. 581-611. (1994).

Thiel, T. Characterization of genes for an alternative nitrogenase in the cyanobacterium Anabaena variabilis. J. Bacteriology 175:6276-6286. (1993). (pdf file)