Study title

Recent isolation of thermoacidophilic methane-oxidizing bacteria belonging to the Verrucomicrobia lineage of evolution has expanded our understanding of the diversity of biological methane oxidation. These microorganisms share the unique ability to use methane, a potent greenhouse gas, as a sole carbon and energy source. Methylacidiphilum kamchatkense, strain Kam1, which my lab isolated from an acidic hot spring in Kamchatka, Russia, will be used as a model for further molecular and physiological analyses of methane oxidation in these organisms, which possess 3-4 conserved operons each encoding 3 particulate methane monooxygenase (Pmo) protein subunits. Preliminary analyses indicate that only one is functionally expressed in Kam1 under standard growth conditions. Through further transcriptional and proteomics analyses, the effect of environmental factors, such as substrate limitation and available copper, on the expression of pmo operons will be assessed as well as the mechanisms for operon regulation. The intracellular polyhedral bodies in these organisms are of particular interest; they may represent a novel subcellular micro-compartment for methane oxidation, compensating for the lack of the typical Pmo-associated intracellular membrane system found in other methanotrophs. These unique intracellular structures may also play a role in detoxification and/or carbon assimilation. The organelles will be purified from Kam1 and their functional role will be assessed. The diversity and activity of methanotroph ic Verrucomicrobia populations from other geothermal regions will also be explored, in part, through international collaboration. Results from this project will provide novel insights into the evolution and diversity of biological methane oxidation, a presumed "ancient" metabolic trait and key process in curbing natural greenhouse gas emissions. The data set consists of DNA sequence data in GBFF format.