The Wrighton Laboratory investigates the role microbes play in methane producing ecosystems. Microbial communities in these systems, and the chemical reactions they catalyze, play vital roles that impact the planet including controlling greenhouse gas emission, mediating human health, and producing energy. We use (meta)genomics in combination with physiological investigations to interrogate microbial community function with applications towards managing environmental resources, stabilizing gastrointestinal function, and improving industrial processes.
Greenhouse Gas production from Wetlands
Because of their ability to purify water, and their capacity to store carbon and other materials, wetlands are commonly referred to as nature’s kidneys. This role is especially vital along the coast of Lake Erie, where agricultural land use, fishing industries, recreational use, and water quality are all intertwined in a delicate balance. Natural dissolved organic matter (DOM) controls the complexation of toxic metals, the degradation of pesticides, and the removal of phosphorus runoff that contributes to feeding harmful Lake-Erie algal blooms. Today wetlands are also recognized as carbon sequestering ecosystems, with important roles in the global carbon budget.
Old Woman Creek, a freshwater estuary located on Lake Erie (a NOAA field station managed by the Ohio Department of Natural Resources) was selected as our research station. This site serves as a model freshwater temperate wetland and has scientific ingrastructure including 33 years of greenhouse gas emission, hydrological, vegetation, and ecological data to complement our microbial investigations. We research carbon cycling microbial metabolisms – examining (1) regions of methanogenesis along redox gradients (2) dissolved organic matter (DOM) biodegradation to identify pathways responsible for C degradation, and (3) the role for aerobic and anaerobic methanotrophs in consuming methane. Ultimately we team up with modelers and chemists to integrate our data and better predict how climate change may impact carbon stability and greenhouse gas emission in wetlands. This research is led by graduate students Jordan Angle and Garrett Smith.
The Marcellus shale in the Ohio-Pennsylvania region is the largest natural gas reserve in the United States. Energy extraction in these systems requires horizontal drilling and hydraulic fracturing (i.e. ‘fracking’) technologies. Despite their economic importance, knowledge of the microbial functionality within these deep (>2000 meters below surface), hot, and briny rock matrices is limited. Our research using microbial community genomics and transcripts, identifies the bacterial, archaeal, and viral members of pristine shale, examines the impact of energy extraction on microbial community dynamics, and identifies metabolic reactions that govern biogeochemical cycling in deep shale environments. Research in the Wrighton laboratory is led by Rebecca Daly, while Kayla Borton and Bridget O’Banion are examining the microbial metabolism in fractured shales using fluid samples from the Utica, Marcellus and Woodford formations.
Gut microbial carbon degrading networks in response to changing climatic conditions
There has been a sharp, inexplicable population decline in moose populations in the continental United States, with declines in Minnesota being the most dramatic. Many causes to the decline have been examined, with nutritional limitations being the focus in our lab. Climate change in arctic and boreal biomes is impacting the chemistry of plants that moose eat and may be increasing the concentration of one particular group of plant chemicals – condensed tannins. Condensed tannins (CT) are phenolic compounds that can inhibit microbial carbon degradation – which provides 70% of a ruminants energy needs. We are exploring the possibility that moose rumen contains microbes that may be able to resist, or degrade CT providing the moose with an ability to adapt to this effect of climate change. Our research uses microbial metagenomics and paired physiological investigations to examine how rumen microbial communities respond to increases in plant CT. Currently we are working with Ann Hagerman at Miami University and David Hoyt at PNNL to characterize CT degradation and the potential intermediates, while pairing this information to metatranscriptomics to reconstruct the microbial degradation pathway. This research, led by graduate student Lindsey Solden has the potential to impact CT and other recalcitrant carbon degradation studies in many other ecosystems.
Salmonella alteration of the biological and chemical gut environment
Salmonella enterica serovar Typhimurium (Salmonella) is one of the leading causes of food-borne illness. This multiple-drug resistant bacterium initiates an inflammatory response that suppresses the healthy gut microbiota, enabling Salmonella Our team is using mouse models to interrogate impacts of Salmonella infection on the microbial and chemical environment of the gut. Along with our collaborators, we integrate 16S rRNA and metagenomics data with whole and targeted metabolites to identify the metabolic and chemical mechanisms by which Salmonella infection restructures the host microbiome. This research is currently led by Kayla Borton.
Methylamine Cycling in the Human Gut
Cardiovascular disease is the leading cause of mortality in the United States, with 1 in every 4 deaths due to heart disease. Recent reports have shown that certain human intestinal microbes may contribute to atherosclerosis leading to cardiovascular disease. These microorganisms convert quaternary amines commonly found in food into trimethylamine, which enters the blood stream. This trimethylamine is converted to trimethylamine-N-oxide in the liver, which can trigger vascular lipid deposition, thus leading to cardiovascular disease. In collaboration with the Krzycki Lab at Ohio State and the Ferguson Lab at Miami University, our team is working to uncover microbial mechanisms of methylamine cycling in the human gut, including those that produce trimethylamine from quaternary amines and those that avoid trimethylamine generation. Specifically, we are coupling metagenomics of human stool samples with targeted metabolites to understand methylamine cycling in the human gut microbiome.
Support and Collaborations
Gastrointestinal health research in arctic ruminants would not be possible without our collaborators at Minnesota Department of Natural Resources, Columbus Zoo & Aquarium, Minnesota Zoo, Alaska Department of Fish and Game, University of Alaska Anchorage.
Salmonella research in the mouse gut is supported by the National Institute of Health (#R01AI116119) and benefits from strong collaborators at The Ohio State University.
Our shale research benefits from strong collaboration with MSEEL, the Marcellus Shale Energy and Environment Laboratory. Research on the pristine shale cores is supported by NSF Dimensions of Biodiversity grant (DEB-1342701), while support from DOE Joint Genome Institute (#1777 and #1931) and Environmental Molecular Sciences Laboratory at Pacific Northwest National Laboratory(#48483) and the Deep Carbon Observatory (# and #) have been critical to our microbial analyses of fractured shales.
Our research at Old Woman Creek is supported by Ohio Water Development Authority (#6835), Department of Energy EMSL (#48641 and #48859), and the DOE Joint Genome Institute (#2049). We also thank Ohio Department of Natural Resources, especially Frank Lopez and Kristi Arend for field access and support.
Other specific collaborators
Mike Wilkins, Ohio State University
Shikha Sharma, West Virginia University
David Cole, Ohio State University
Paula Mouser, Ohio State University
Gil Bohrer, Civil, Environmental and Geodetic Engineering
Yo Chin, Earth Sciences
Chris Miller, Integrative Biology
Jeffrey Firkins (OSU), Animal Sciences
William Collins (ADFG) and Donald Spalinger (UAA), Plant and Animal Physiology
Michelle Carstensen (MDNR) and Barbara Wolfe (OSU), Wildife Health
Brian Ahmer, Microbial Infection and Immunity
Venkat Gopalan, Chemistry and Biochemistry
Vicki Wysocki,Chemistry and Biochemistry
Research in the news
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