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In Situ Biofilm Metabolism Studies
| CO-PI(s): | Brad Bebout |
| James Lumpp |
| Bill Dieter |
University of Kentucky
The hunt for some form of life elsewhere in our universe may spur the development of many robot orbiters, landers and rovers to study the surface of Mars in the coming years. Instead of probing for signs of life on Mars’ surface, some researchers have suggested looking inside the planet, where there is mounting evidence of water ice near the equator and the potential for underground aquifers that could support basic microbial organisms. Single-celled organisms including bacteria thrive on all parts of the earth’s surface, from the boiling hot waters of thermal springs to the more hospitable soils of gardens. Until recent years, few scientists thought to look deep inside the earth for new life, believing that this realm was essentially sterile. But that belief was wrong. Most microbes in nature are not found as homogeneous suspensions of free cells, but are attached to solid surfaces and to one another within a protective film of secreted polymers. Cells within these biofilms experience gradients of nutrients, oxygen, pH and metabolic byproducts with depth, and are known to express differing phenotype and metabolism in response to these environmental gradients. These changes have drastic effects upon biofilm properties, and may have a direct relation to their resistance to antibiotics in a medical scenario. Current sample-extraction methods cannot capture representative depth-dependent metabolite concentrations, because metabolism changes occur rapidly (within milliseconds) during the environmental perturbation that accompanies extraction. Further, invasive extraction methods can damage the sample, rendering it useless for subsequent measurements. Thus, in situ spatially resolved analytical techniques are required for the metabolic characterization of biofilms. Specific Aims 1. to identify and quantify a subterranean bacterial species found in ground water, Shewanella oneidensis, using SSSSentry, a new miniature solid-state spectral imager with no moving parts. 2. Map distribution of S. oneidensis biofilm as cells grow and multiply with SSSI.
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