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Articles 1 - 6 of 6
Full-Text Articles in Microbiology
Copper-Mediated Regulation Of A Traditional Iron Uptake System In Uropathogenic Escherichia Coli., George Lwanga Katumba
Copper-Mediated Regulation Of A Traditional Iron Uptake System In Uropathogenic Escherichia Coli., George Lwanga Katumba
Arts & Sciences Electronic Theses and Dissertations
Transition metals constitute an important part of the host-pathogen interface. Iron is an essential nutrient that functions as a cofactor for numerous bacterial and host proteins, as either a ligand for oxygen in carrier proteins or an enzyme catalytic site due to its natural redox properties. As part of the innate immune response, infected hosts sequester iron from pathogens to limit their growth, a phenomenon known as nutritional immunity. On the other hand, copper ions are deployed at infection sites as a potent antimicrobial agent to kill bacteria. The ability to survive within multiple, often harsh, microenvironments is fundamental to …
Post-Translational Modifications And Functional Studies Of Dksa In Escherichia Coli, Andrew Charles Isidoridy
Post-Translational Modifications And Functional Studies Of Dksa In Escherichia Coli, Andrew Charles Isidoridy
Legacy Theses & Dissertations (2009 - 2024)
DksA is a bacterial gene regulator that functions synergistically with the stress alarmone ppGpp to mediate the stringent response. DksA also functions independently of ppGpp to regulate transcription of a number of genes. DksA function is dependent on its binding affinity to RNA polymerase and requires specific interactions between RNAP and catalytic amino acids located on the coiled coil tip, D74 and A76. While much of the previous work on DksA has focused on understanding the mechanisms of action and the numerous gene targets for transcriptional regulation, little is known about the mechanisms by which DksA expression and function may …
Transcriptional Regulation Of Dksa In E. Coli, Daniel Thomas Woods
Transcriptional Regulation Of Dksa In E. Coli, Daniel Thomas Woods
Legacy Theses & Dissertations (2009 - 2024)
DksA is a global transcription factor that binds RNAP directly to regulate the expression of many genes and operons, including ribosomal RNA, in a ppGpp-dependent or ppGpp–independent manner. It is also involved in facilitating the process of DNA replication by removing stalled transcription elongation complexes that could block the progress of the replication fork. In addition, DksA is important for colonization, establishment of biofilms, and pathogenesis. In order to sustain these various functions, an adequate level of cellular DksA is required. This work tested the hypothesis that the E. coli dksA is substantially regulated at the level of transcription. Using …
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 …
Mscs-Like Mechanosensitive Channels In Plants And Microbes, Margaret E. Wilson, Grigory Maksaev, Elizabeth S. Haswell
Mscs-Like Mechanosensitive Channels In Plants And Microbes, Margaret E. Wilson, Grigory Maksaev, Elizabeth S. Haswell
Biology Faculty Publications & Presentations
The challenge of osmotic stress is something all living organisms must face as a result of environmental dynamics. Over the past three decades, innovative research and cooperation across disciplines have irrefutably established that cells utilize mechanically gated ion channels to release osmolytes and prevent cell lysis during hypoosmotic stress. Early electrophysiological analysis of the inner membrane of Escherichia coli identified the presence of three distinct mechanosensitive activities. The subsequent discoveries of the genes responsible for two of these activities, the mechanosensitive channels of large (MscL) and small (MscS) conductance, led to the identification of two diverse families of mechanosensitive channels. …