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Full-Text Articles in Physical Sciences and Mathematics
Mutagenic And Spectroscopic Investigation Of Ph Dependent Cooa Dna Binding, Brian R. Weaver
Mutagenic And Spectroscopic Investigation Of Ph Dependent Cooa Dna Binding, Brian R. Weaver
Chemistry Honors Papers
The carbon monoxide (CO) sensing heme protein, CooA, is a transcription factor which exists in several bacteria that utilize CO as an energy source. CooA positively regulates the expression of coo genes in the presence of CO such that the corresponding proteins may metabolize CO. The present studies have yielded the unexpected result that Fe(III) CooA binds DNA tightly at pH < 7, deviating from all previously reported work which indicate that CooA DNA binding is initiated only when the exogenous CO effector reacts with the Fe(II) CooA heme. This observation suggests that the disruption of one or more salt bridges upon effector binding may be a critical feature of the normal CooA activation mechanism. To test this possibility, several protein variants that eliminated a selected salt bridge for the CooA homolog from Rhodospirillum rubrum were prepared via site-directed mutagenesis. Samples of these variant proteins, which were overexpressed in Escherichia coli, were then characterized by spectroscopic methods and functional assays to investigate the impact these mutations had on CooA heme coordination …
Comparison Of Two Separation Methods For Biological Particles: Field-Flow Fractionation (Fff) And Sucrose Density Gradients, Cody E. Garrison
Comparison Of Two Separation Methods For Biological Particles: Field-Flow Fractionation (Fff) And Sucrose Density Gradients, Cody E. Garrison
OES Theses and Dissertations
Sucrose gradient centrifugation and Field-flow fractionation (FFF) are two different particle separation methods that overcome the problems of similar size microorganisms clumping together during standard filtration methods. FFF separates particles based on size and density via the parabolic velocity profile of laminar flow in a ribbon-like channel. The sucrose method separates particles via centrifugation in a density gradient. Both techniques worked well in separating eukaryotic from prokaryotic microbes, with the preferred method depending on the type and relative abundance of organisms to be separated. Minicells were separated from mother cells in transformed Escherichia coli cultures, heterotrophic flagellates (e.g., Diplonema papillatum …
Fecal Indicator Bacteria In Knitting Mill Creek With A Comparison Of Methods Used To Enumerate E. Coli, Manju Nagarajan
Fecal Indicator Bacteria In Knitting Mill Creek With A Comparison Of Methods Used To Enumerate E. Coli, Manju Nagarajan
OES Theses and Dissertations
This research seeks to evaluate the impact of an urban, multi-use neighborhood on the bacteriological quality of water in Knitting Mill Creek, a blind arm of the Lafayette River, a sub-estuary of the lower Chesapeake Bay. A principal objective was to determine the effects of rainfall, a surrogate for run-off, on water-column concentrations of fecal-indicator bacteria (FIB). I collected water samples weekly (September 2009-December 2010) and biweekly (January 2010-December 2011) at a storm-sewer outfall and a nearby marina and quantified their E. coli and enterococci concentrations using Colilert-18 and Enterolert, most-probable-number assays. In addition, I took monthly samples for these …