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Full-Text Articles in Microbiology

Physiological Characterization Of Prochlorococcus Under Abiotic Stressors Temperature And Hydrogen Peroxide, Lanying Ma Dec 2015

Physiological Characterization Of Prochlorococcus Under Abiotic Stressors Temperature And Hydrogen Peroxide, Lanying Ma

Doctoral Dissertations

Cyanobacteria of the genus Prochlorococcus are the smallest and most abundant phytoplankters in the ocean. Temperature is a major influence on Prochlorococcus abundance and distribution in the ocean, but the physiological basis for this relationship is not well understood. In other microbes, lipid and fatty acid composition have been shown to be influenced by temperature, and temperature has also been proposed as a relevant factor for setting the elemental allocation in marine phytoplankton. In this study, we found that percentage of fatty acids unsaturation was negatively related with temperature in some Prochlorococcus strains, but this was not universal. Temperature had …


Bacterial Diversity And Function Within An Epigenic Cave System And Implications For Other Limestone Cave Systems, Kathleen Merritt Brannen-Donnelly Dec 2015

Bacterial Diversity And Function Within An Epigenic Cave System And Implications For Other Limestone Cave Systems, Kathleen Merritt Brannen-Donnelly

Doctoral Dissertations

There are approximately 48,000 known cave systems in the United States of America, with caves formed in carbonate karst terrains being the most common. Epigenic systems develop from the downward flow of meteoric water through carbonate bedrock and the solutional enlargement of interconnected subsurface conduits. Despite carbonate karst aquifers being globally extensive and important drinking water sources, microbial diversity and function are poorly understood compared to other Earth environments. After several decades of research, studies have shown that microorganisms in caves affect water quality, rates of carbonate dissolution and precipitation, and ecosystem nutrition through organic matter cycling. However, limited prior …


Epidemiology Of Select Species Of Filarial Nematodes In Free-Ranging Moose (Alces Alces) Of North America, Caroline Mae Grunenwald Dec 2015

Epidemiology Of Select Species Of Filarial Nematodes In Free-Ranging Moose (Alces Alces) Of North America, Caroline Mae Grunenwald

Doctoral Dissertations

North American moose (Alces alces) are a culturally and economically valued species. Recent population declines raise concern for the survivability of this natural resource. The Minnesota population has experienced the most dramatic decline, with a 60% loss in total numbers since 2006. Nematode parasites, particularly some species of filarids, are important pathogens of moose and could be contributing to morbidity and mortality. This study investigates the eco-epidemiology of two filarial parasites of moose: Rumenfilaria andersoni and Elaeophora schneideri. By surveying cervid species from six U.S. states, we discovered R. andersoni was present in moose from all sample locations …


Rare Occurrences Of Free-Living Bacteria Belonging To Sedimenticola From Subtidal Seagrass Beds Associated With The Lucinid Clam, Stewartia Floridana, Aaron M. Goemann Dec 2015

Rare Occurrences Of Free-Living Bacteria Belonging To Sedimenticola From Subtidal Seagrass Beds Associated With The Lucinid Clam, Stewartia Floridana, Aaron M. Goemann

Masters Theses

Lucinid clams and their sulfur-oxidizing endosymbionts comprise two compartments of a three-stage, biogeochemical relationship among the clams, seagrasses, and microbial communities in marine sediments. A population of the lucinid clam, Stewartia floridana, was sampled from a subtidal seagrass bed at Bokeelia Island Seaport in Florida to test the hypotheses: (1) S. floridana, like other lucinids, are more abundant in seagrass beds than bare sediments; (2) S. floridana gill microbiomes are dominated by one bacterial operational taxonomic unit (OTU) at a sequence similarity threshold level of 97% (a common cutoff for species level taxonomy) from 16S rRNA genes; …


Identification Of Purinyl-Cobamide As A Novel Corrinoid Cofactor Of Tetrachloroethene Reductive Dehalogenases In Desulfitobacterium Spp., Meng Bi Dec 2015

Identification Of Purinyl-Cobamide As A Novel Corrinoid Cofactor Of Tetrachloroethene Reductive Dehalogenases In Desulfitobacterium Spp., Meng Bi

Masters Theses

Corrinoids (e.g. vitamin B12) [cyanocobalamin] are a group of structurally similar, cobaltcontaining tetrapyrrole compounds involved in a number of important biochemical reactions. In organohalide respiration, vitamin B12 analogues carrying different lower bases are obligate cofactors for the reductive dehalogenases (RDases) that catalyze reductive dechlorination reactions. The focus of this research was on the isolation and characterization of a novel natural corrinoid cofactor that enables the dechlorination-coupled energy conservation in organohaliderespiring Desulfitobacterium strains. Analysis of the purified corrinoid in the cyano form using a combination of high-performance liquid chromatography (HPLC), UV-Vis [Ultraviolet–visible spectroscopy] and ultra-performance liquid chromatography-high-resolution mass …


The Role Of Phosphatidylserine And Phosphatidylethanolamine In Candida Albicans Virulence, Sarah Elizabeth Davis Aug 2015

The Role Of Phosphatidylserine And Phosphatidylethanolamine In Candida Albicans Virulence, Sarah Elizabeth Davis

Doctoral Dissertations

In hospitalized patients with neutropenia, Candida albicans is the fourth leading cause of systemic bloodstream infections, which have a mortality rate of approximately 30 %. The phosphatidylserine synthase enzyme of C. albicans, Cho1p, appears to be a good drug target as a mutant lacking this enzyme (the cho1Δ/Δ [null mutant]) is avirulent in animal models of Candida infections and this enzyme is not conserved in humans. We discovered that the loss of phosphatidylserine (PS) synthesis affects C. albicans' expression of the Als3p adhesin, a virulence protein, and loss of PS synthesis also compromises the cell wall, causing increased …


Cmv Chemokines And Co-Infection: A Dissemination Plot That Peptides Can Foil, Pranay Dogra Aug 2015

Cmv Chemokines And Co-Infection: A Dissemination Plot That Peptides Can Foil, Pranay Dogra

Doctoral Dissertations

Human Cytomegalovirus (HCMV) is the leading cause of both non-hereditary mental retardation and hearing loss, and CMV infection/reactivation causes serious complications in transplant and immune compromised patients. Due to these issues, development of a CMV vaccine and/or therapeutics is required. To achieve this goal, it is necessary to gain a better understanding of CMV pathogenesis. Because of its coevolution with humans, HCMV has evolved genes with homology to human immune modulatory genes. Several of these genes help CMV establish a successful and lifelong infection within the host. An example is the viral CXC chemokine homolog UL146 gene (vCXCL-1). UL146 varies …


Geochemical Control Of Methanogenesis In Cape Lookout Bight, North Carolina, Richard Kevorkian Aug 2015

Geochemical Control Of Methanogenesis In Cape Lookout Bight, North Carolina, Richard Kevorkian

Masters Theses

Hydrogen exerts thermodynamic control over the exclusion of methanogens by sulfate reducers in Cape Lookout Bight, NC, marine sediments. This has been demonstrated by previous in situ measurements, but has never been demonstrated in a batch incubation of unamended sediments and has never been combined with identification of the microorganisms involved in this process. We made triplicate anoxic incubations of sediments from the upper 3 cm of sediment over 122 days while taking weekly samples for DNA extraction, cell counts, and measurements of methane, sulfate, and hydrogen. The headspaces of the bottles were initially gassed with nitrogen and the third …


Genetic Diversity, Population Structure, And Evolution Of Virulence In Toxoplasma Gondii, Elliot Keats Cullen Shwab May 2015

Genetic Diversity, Population Structure, And Evolution Of Virulence In Toxoplasma Gondii, Elliot Keats Cullen Shwab

Doctoral Dissertations

Toxoplasma gondii is among the most widespread eukaryotic pathogens known. It chronically infects approximately one third of the world’s human population and has been isolated from an extremely diverse array of globally distributed mammals and birds. Understanding the structure of the worldwide T. gondii population enhances our understanding of the factors that have shaped that structure and led to the proliferation of one of the most evolutionarily successful pathogens on Earth. Herein we collate genotypic data from global isolates, demonstrating that T. gondii possesses a unique population structure in which only a small number of genotypes dominate throughout the northern …


Thermal Inactivation Of Shiga Toxin-Producing Escherichia Coli In Foods, Malcond David Valladares May 2015

Thermal Inactivation Of Shiga Toxin-Producing Escherichia Coli In Foods, Malcond David Valladares

Doctoral Dissertations

Emerging non-O157 Shiga toxin-producing Escherichia coli (STEC) were recently added to the zero tolerance policy by the USDA-FSIS. Therefore, the precise characterization of their thermal inactivation kinetics in different foods and the effect of stress on thermal inactivation are needed. This research aimed at determining the heat inactivation kinetics of non-O157 and O157 STECs in buffer and model food matrices and the effects of DnaK levels on thermal resistance after acid and heat-shock. Thermal inactivation was carried out in either in 2-ml glass vials or nylon vacuum-sealed bags for buffer and food (spinach, ground-beef, turkey deli-meat, pasta) samples, respectively. Vials …


Elucidating The Impact Of Roseophage On Roseobacter Metabolism And Marine Nutrient Cycles, Nana Yaw Darko Ankrah May 2015

Elucidating The Impact Of Roseophage On Roseobacter Metabolism And Marine Nutrient Cycles, Nana Yaw Darko Ankrah

Doctoral Dissertations

As the most abundant biological entities in marine environments, viruses are an important component of marine food webs. The activity of viruses contributes significantly to the mortality of marine microorganisms, ultimately influencing biological function and chemical composition of aquatic systems by impacting species composition and flow of carbon, nitrogen and other nutrients. Despite the growing recognition that viral activity contributes to marine biogeochemical cycles, the extent to which virus infection reshapes host metabolism and the effect of this alteration on the composition of host lysate remains poorly understood. Additionally, the degree to which natural bacterioplankton communities metabolise the released lysate …


Positive Regulation Of Localization Of Cell Division Proteins In Escherichia Coli, William P. Deaderick May 2015

Positive Regulation Of Localization Of Cell Division Proteins In Escherichia Coli, William P. Deaderick

Chancellor’s Honors Program Projects

No abstract provided.


Molecular Epidemiology, Genotyping, And Mat Testing Of Toxoplasma Gondii, Jack Kang May 2015

Molecular Epidemiology, Genotyping, And Mat Testing Of Toxoplasma Gondii, Jack Kang

Chancellor’s Honors Program Projects

No abstract provided.


Deep Groundwater And Potential Subsurface Habitats Beneath An Antarctic Dry Valley, Jill A. Mikucki, E. Auken, S. Tulaczyk, R. A. Virginia, C. Schamper, K. I. Sørensen, P. T. Doran, H. Dugan, N. Foley Apr 2015

Deep Groundwater And Potential Subsurface Habitats Beneath An Antarctic Dry Valley, Jill A. Mikucki, E. Auken, S. Tulaczyk, R. A. Virginia, C. Schamper, K. I. Sørensen, P. T. Doran, H. Dugan, N. Foley

Microbiology Publications and Other Works

The occurrence of groundwater in Antarctica, particularly in the ice-free regions and along the coastal margins is poorly understood. Here we use an airborne transient electromagnetic (AEM) sensor to produce extensive imagery of resistivity beneath Taylor Valley. Regional-scale zones of low subsurface resistivity were detected that are inconsistent with the high resistivity of glacier ice or dry permafrost in this region. We interpret these results as an indication that liquid, with sufficiently high solute content, exists at temperatures well below freezing and considered within the range suitable for microbial life. These inferred brines are widespread within permafrost and extend below …


Lessening Malaria Parasite Burden With Yogurt, Alivia M. Shasteen, Sarah W. Lebeis, Nathan Schmidt Apr 2015

Lessening Malaria Parasite Burden With Yogurt, Alivia M. Shasteen, Sarah W. Lebeis, Nathan Schmidt

Microbiology Publications and Other Works

The prevalence of malaria across the globe, particularly in countries with minimal health care availability, makes it a top priority for medical researchers. Dr. Nathan Schmidt’s lab discovered that mice from vendors from different geographical locations infected with malaria pathogens yielded significantly different parasite burdens. Researchers discovered that the reason behind the differences in parasite burden was a result of the different compositions of the gut microbiomes of the mice from the different vendors. The research in which I engaged involved manipulating the contents of the gut microbiome through yogurt in the hopes of lessening the parasite burden. Our results …