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2020

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Can Zooplankton On The North American Great Plains ‘Keep Up’ With Climate-Driven Salinity Change?, Mariam Elmarsafy Jan 2020

Can Zooplankton On The North American Great Plains ‘Keep Up’ With Climate-Driven Salinity Change?, Mariam Elmarsafy

Theses and Dissertations (Comprehensive)

The Great Plains of North America are projected to become more arid as the climate changes over the next century. Salinity levels for lakes in this region are linked to climate, suggesting that lakes will become more saline as the climate becomes drier. One group of organisms that might be affected by increased salinity levels are the zooplankton, aquatic invertebrates that transfer energy from primary producers to macroinvertebrates and fish. Little is known about the ability of zooplankton to adapt to long-term increases in lake salinity levels. For my thesis, I used resurrection ecology to examine how a common zooplankter, …


Investigating Diel, Seasonal, And Interannual Variability Of Dissolved And Particulate Stable Carbon Isotope Values In A Eutrophic Boreal Lake, Rachel Henderson Jan 2020

Investigating Diel, Seasonal, And Interannual Variability Of Dissolved And Particulate Stable Carbon Isotope Values In A Eutrophic Boreal Lake, Rachel Henderson

Theses and Dissertations (Comprehensive)

Lakes are globally significant sources, sinks, and conduits of carbon. Cultural eutrophication of freshwater promotes the growth of phytoplankton blooms, which can transform, respire, and sequester large amounts of carbon. Analysis of stable carbon isotopes is a common tool to study the movement of carbon through the aquatic carbon cycle. The causes of temporal variability in δ13C values at different timescales are not well understood, and differ between lakes. In this study, I investigated diel, seasonal, and interannual variability in δ13C values of dissolved inorganic carbon (DIC) and particulate organic carbon (POC) in Lake 227, an …


Functional Characterization Of Proteins From A Putative Chondroitin Sulfate A Degrading Operon And The Crystal Structure Of An Exo-N-Acetylgalactosamine-4-Sulfatase From Tannerella Forsythia, Peter Nguyen Jan 2020

Functional Characterization Of Proteins From A Putative Chondroitin Sulfate A Degrading Operon And The Crystal Structure Of An Exo-N-Acetylgalactosamine-4-Sulfatase From Tannerella Forsythia, Peter Nguyen

Theses and Dissertations (Comprehensive)

Advanced periodontitis has been shown to have strong associations with the residence of a bacterial triad of Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola also known as the red complex. These bacteria were previously thought to be asaccharolytic, making them better suited to survive in deep in periodontal pockets where access to carbohydrates from food is limited. Information gathered from genomic analysis suggested that upregulation of an operon (BFO2285-BFO2295, BFO3043) could confer the capacity for T. forsythia to degrade chondroitin-4-sulfate, the principle glycosaminoglycan of alveolar bone tissue. Bioinformatics analysis suggested the operon was similar to an operon found in Bacteroidetes …


The Role Of Streptococci In Oral Periodontitis: Growth And Disruption Of Yellow Complex Bacteria, Megan Gordon Jan 2020

The Role Of Streptococci In Oral Periodontitis: Growth And Disruption Of Yellow Complex Bacteria, Megan Gordon

Theses and Dissertations (Comprehensive)

Periodontitis is described as the inflammation of the periodontium and affects millions of people worldwide. This disease is caused by biofilm growth of certain bacteria on the tooth surface, adjacent to the gum tissue in the oral cavity. There are currently treatments against severe periodontitis, such as oral surgery and use of broad-spectrum antibiotics, but they fail to target the specific bacteria associated with periodontitis. Socransky et al., (1998), identified the preponderance for specific organisms in distinct areas of the subgingival pockets to associate with different bacteria forming consortia and complexes. The yellow complex, containing facultatively anaerobic, Gram positive …