What factors allow single-celled microbial organisms to not only survive, but actively seek out environments that humans consider highly toxic? Scientists have learned much about how these tiny living creatures function, facilitating breakthroughs in medical, energy, and bioremediation sciences. However, the understanding of how microorganisms grow and thrive in harsh environments remains largely cloaked in mystery. The ability to predict how microorganisms will respond to environmental changes or the knowledge of the types of reactions that occur inside and outside their cells is vastly under-represented. In a large part, this is due to the limited ability to identify the small molecules produced and consumed by microbes (metabolites). This unknown microbial metabolite landscape limits the understanding of the microbial processes playing key roles in the regulation of biogeochemical cycles, bioremediation, bioenergy production, as well as the human microbiome. In this work, state of the art techniques will be used to find and characterize metabolites that up until now have been largely invisible to researchers. The work will result in excellent training opportunities for undergraduate and graduate students, especially from under-represented groups such as Native Americans, as well as a series of lectures at the Thermal Biology Institute that provide an opportunity for effective outreach and give the public a view of the importance of microbes.
This project focuses on the discovery of unknown microbial metabolites produced by bacteria using the Gram-negative soil bacterium Agrobacterium tumefaciens strain 5A as model. This bacterium is a model for understanding how microbes metabolize arsenic, a critical environmental toxin found in contaminated soils and water supplies, and a top priority for bioremediation efforts. Focusing on how microbes metabolize arsenic is important because microorganisms influence arsenic toxicity and bioavailability in every environment thus far studied. Thus, characterization of arsenicals produced by microbes are a focal point of this project that will employ state-of-the-art nuclear magnetic resonance (NMR) and mass spectrometry (MS) metabolomics technology to identify unknown microbial compounds, including arsenicals (i.e. methylated species, arsenolipids, arsenosugars). Importantly, the analytical approaches developed in this project will be applicable to many facets of biology. The project will greatly enhance researchers' abilities to probe the richness of the metabolomes of microbes, and to gain a much better appreciation for the diversity of microbial unknown small molecules. Focusing on A. tumefaciens as a model system will enable the identification and structural characterization of novel organo-arsenic compounds and arsenolipids. Results from these studies will bring transformative knowledge to the field of microbe-arsenic interactions relevant to scientific research aimed at predicting how arsenic disrupts/alters bacterial metabolism in situ, with broader implications for biogeochemical carbon and nitrogen cycling in nature when microbes must deal with arsenic.