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Project Progress

Our research focuses on psychrophilic (cold-loving) microorganisms and their cold-active enzymes. This includes the analysis of psychrophiles and their enzymes from cold environments including the subseafloor, Antarctica, lakes, and cold soils. We have characterized numerous isolates and cloned genes encoding their cold-active enzymes. We are currently examining a protease with high specific activity at low temperatures and with chelators. Another PSARC project investigates microorganisms deposited over 100,000 years ago in the basal portion of a Greenland glacier (GISP2) ice core. Research with this ice core serves as a model for severe conditions, such as cold temperatures, nutrient and oxygen limitations, desiccation, pressure, etc. that could exist extra-terrestrially. We demonstrated that an abundant viable (10⁷ cells/ml) microbial population exists trapped in the ice core and that many are ultra-small cells that pass through filters with pore sizes as small as 0.1 microns. Growth studies showed that some isolates retain their small cell size throughout their growth cycles in different media suggesting that they are intrinsically small. These ultra-small cells compose a large fraction of the uncultivated microorganisms in many environments, and thus, our results are relevant to other studies where samples were filtered and only the cells trapped on filters examined. We are improving detection methods for the archaeal populations in the ice core, plus other environments such as the subseafloor, where these cells may be in low numbers. One method we are testing and optimizing is the use of whole genome amplification kits for prokaryotic cells for potential metagenomic studies. If genomic DNA can be reproducibly amplified without the need for specific primers, then it will be possible to detect the presence of minor phylotypes in a sample. This could increase the possibility of detecting the presence of life elsewhere.