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My main research examines water flow from glaciers. In my work on several glaciers in Antarctica we have observed subsurface pockets of water called cryoconite holes. Although common on many glaciers, these holes are unusual in that they have an ice lid 10's of centimeters thick. Below the lid a small head space of air exists above several 10's of centimeters of water below. The hole diameter varies from 10 - 100 cm. The ice surface remains frozen and little or no meltwater exists. Our observations reveal that microbial life is present despite its isolation from the atmosphere. We believe that the cryoconite holes freeze solid in the winter and regenerate in the summer after which the microbial life reactivates. The current focus of our study is on the chemical balance in the holes and quantification of the nutrient sources to maintain the biological activity. These cryoconite holes act as refugia for life and may be important analogs for conditions during "snowball earth" or for extraterrestial life in icy regimes on other planets.
My research interests, as they relate to the theme of life in extreme environments, focus on the molecular mechanisms responsible for structural stabilization of macromolecules in thermophilic organisms. Specifically I am interested in 1) understanding how chemical modification of nucleoside bases contributes to tertiary structural stability in RNA, and 2) characterizing the biochemical pathways responsible for the formation of modified bases in RNA. Because life may have emerged on earth under conditions similar to those found in contemporary thermal environments, elucidating the factors responsible for RNA stability also has direct relevance to understanding the structural requirements faced by primitive organisms in the early history of earth, as well as the replicating systems predating the emergence of life on earth in the putative "RNA World". Indeed, an understanding of the molecular physiology of extant organisms inhabiting extreme environments is fundamental to establishing the boundary conditions for the early evolution of life on earth, as well as evaluating the potential for life on other worlds.
My research interests are in the origins of life and the early evolution of self-replicating molecular systems. Our lab uses populations of RNA as a model system for examining the parameters that may have been important in making the transition from abiotic chemistry to truly life-like biological chemistry. We are currently using in vitro selection techniques to test evolutionary hypotheses about a putative "RNA World". The possibility that life originated in an environment that by today's standards would be considered extreme, and the reality that life in extraterrestrial locations would certainly be found in extreme environments, behooves us to consider using conditions for these in vitro experiments that are distinctly non-physiological.
My major research focus is the viruses of the extremely thermophilic archaeon Sulfolobus. These viruses are completely different, both in their structures and sequences, from any other known viruses. We are interested in how these viruses function at very high temperatures (80C = 176F) and high acidity (pH below 4). We also use these viruses as tools to develop molecular genetics for extremely thermophilic Archaea. The same viruses can also be used as expression vectors for novel enzymes from extreme thermophiles. Finally I am very interested in transcriptional regulation in Sulfolobus, since there are some very striking parallels to transcriptional regulation in eukaryotic cells, including humans. Sulfolobus is, however a much more tractable system for studying these basal transcriptional mechanisms.
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