Dr. Harry Kurtz, Jr.

Assistant Professor
Ph.D. Bacteriology
1989, University of Idaho

Research Interests
Microbial Physiology
Microbial Diversity and Ecology

Office: 165 Jordan Hall
Phone: (864) 656-6915
Email: hkurtz@clemson.edu
Website: Kurtz Lab Website

Research Activities

We are primarily interested in understanding how bacteria have evolved to survive in oligotrophic (dilute nutrient) ecosystems. Information regarding this process is being gleaned from two different studies that examine microbial life in two different contexts. First, we are looking at the microbiological diversity found in desert ecosystems (southeastern Utah), specifically those associated with rock surfaces and sedimentary deposits. From this work, several lines of research are achieving results. We have been able to show that microbial communities harden sandstone surfaces by about 1 atm and therefore likely play a role in moderating wind and water erosion. Our diversity work also detected the presence of potential iron-reducing bacteria in these communities, causing us to test for the presence of free ferrous iron, which was found at higher than expected concentrations. These data have resulted in a biogeochemical hypothesis that states that the iron-reducing bacteria are involved in a regional phenomenon known as iron-bleaching. Iron-bleaching is a visible reduction in iron content within the same rock stratum. In southeastern Utah, this phenomenon is manifested as swathes of pale pink sandstone amidst larger formations of red sandstone. Marjorie Chan and her research group has explained this as being a paleogeochemical phenomenon that took place millions of years ago when a hydrocarbon reservoir was breached. Our hypothesis does not refute this explanation, but it does suggest that the bleaching process may be ongoing. Climatalogically, the study region has been undergoing an extreme drought that is now in its seventh year. Because we have a sample collection that starts in 1998 and ends in 2005, we are in the position to ask the question about climate effects on microbiological systems. More simply put, are bacteria that were previously found in this set of ecosystems still present or have they lost a portion of their biodiversity? While our work has not directly addressed this question yet, hints within the current data suggest this might be so, but it is vitally important that we develop a deeper pool of data from which we can derive an answer to this question.

Our second major line of research focuses on the aquatic bacterium, Caulobacter crescentus. This organism has served as an excellent model to study complex bacterial development systems for nearly 40 years. Because of this, much is known about the genetics of this bacterium and the regulation of its various developmental pathways. However, little is known about the ecophysiology of this microbe other than its basic nutritional requirements, general habitat range and relative abundance. The strain of that we work with prefers oligotrophic (dilute nutrient) conditions such as those found in freshwater habitats. In aquatic systems, iron is and extremely limited resource, found at around 6-35 nM---10-20X less than required for most aerobic microbes. Thus, we are examining the high affinity iron transport system of this bacterium. This work has the potential to fill a gap in our knowledge regarding iron transport by Gram negative bacteria. Much is known about these systems with respect to pathogenic bacteria as well as symbiotic organisms, but very little is known about these systems in environmental bacteria. Are the regulatory schemes and proteins involved the same, similar or different? This general question is currently being addressed in our laboratory and it will help us with our overarching question about how bacteria have evolved to survive in conditions of scarcity.

Recent Publications

CFu’ad T. Haddadin, Harry Kurtz, and Sarah W. Harcum. (in press). Serine hydroxamate and the transcriptome of high cell density recombinant Escherichia coli MG1655

Kurtz, Jr., H. D. and Rosemary Cox. (in press). Microbial Biofilm Effects on Local Microconditions (cm range) in Arid Environments and Their Potential Involvement in Iron Geochemistry

Kurtz, Jr., H. D., Christopher Reisch, and Rosemary Cox (2005). Development of a microcosm system suitable for the study of desert endolithic microbial ecosystems. Biofilms 2(2):145-152.

Kurtz, Jr., H. D. 2002. Endolithic microbial communities as bacterial biofilms: The role of EPS. Molecular Ecology of Biofilms, Ed. R. J. C. McLean and A. W. Decho, Horizon Press, UK.

Kurtz, Jr., H. D. and D. I. Netoff. 2001. Stabilization of friable sandstone surfaces in a desiccating, wind-abraded environment of south-central Utah by rock surface microorganisms. Journal of Arid Environments 48:89-100.

Additional Publication Resources