Physical Sciences and Mathematics Commons^™

The Effects Of Hydrologic Heterogeneity On Harmful Algal Blooms In Freshwater Reservoir, Lake Sinclair, Georgia, Margaret Blackledge

Biology Theses

Aquatic habitats are frequently studied after a major water quality problem like the occurrence of an algal bloom. In this study, A proactive rather than a reactive response was considered, where the complexity of conditions conducive to uncontrolled cell growth were studied before a bloom took place by sampling regularly. This study aimed to monitor water quality by monthly sampling of algal communities for approximately one year. As the base of the aquatic food web, algae are a highly diverse group of organisms with varying sensitivity to physical and chemical changes in the environment. Four shallow sites were monitored at …

Genetically Engineered Thermosynechococcus Elongatus Bp1: Assessment Of Potential Biorisks And Biofuel Production, Thu Ho Anh Nguyen-Jones

Chemistry & Biochemistry Theses & Dissertations

According to the International Energy Outlook 2019, released by the U.S. Energy Information Administration, it is projected that the energy consumption will increase up to 50% between 2018 and 2050 worldwide. As fossil fuel being a finite source of energy with the risk of depletion, many countries are now facing an energy security crisis. Therefore, it is important to develop other renewable and sustainable energy sources that will allow countries to shift away from depending on fossil fuels. Among several types of renewable energy, biofuel production using genetically engineered cyanobacteria is capturing much interest due to its many advantages. Different …

Don't Sell Them Short, There's More To Bacterial Natural Products Than Antibiotics, Alison Clare Domzalski

Dissertations, Theses, and Capstone Projects

Recent genomic studies of microbiomes have revealed an overwhelming number of biosynthetic genes of unknown function. Most of these “cryptic” biosynthetic genes are not expressed in laboratory monocultures of individual microbes. Thus, there remains tremendous untapped potential for natural products discovery. Here we employ mixed microbial culture (MMC) as a simple yet powerful approach to awaken cryptic biosynthetic gene clusters. Our preliminary studies demonstrated that arrays of metabolites could be induced in MMCs upon environmental cues, such as surface adhesion. Using this system, we have screened, identified, and isolated bioactive bacterial metabolites, which were characterized structurally and biologically. Of the …

Polycyclic Aromatic Hydrocarbons And The Microbiomes Of Two Benthic Species, Samantha Ells

Master's Theses

The presence of oil has been shown to affect the microbiomes of the water column, sediments, and organisms, both by altering the diversity and the composition of those microbial communities. If the microbiome is altered it may no longer provide benefits to its host organism, impacting its ability to survive. Thus, it is important to understand the effects of large-scale contamination events including the Deepwater Horizon oil spill. This study set out to examine the effects of oil exposure on the microbiome of two benthic species, southern flounder (Paralichthys lethostigma) and eastern oysters (Crassostrea virginica) to further understand the effects …

Investigation Into Bacterial Impairment Of Greene And Polk County Water Systems, John C. Kincaid

MSU Graduate Theses

Bacterial impairment of water systems is a major issue facing mankind. Bacteria that are introduced into a system have the potential to cause harmful diseases to wildlife and humans. In Greene and Polk counties, many water systems have become bacterially impaired over the years. Despite this, little is known about the contamination of known harmful bacteria in this region. To address this issue, I investigated the presence of known human pathogens across water systems in these two counties, many of which have displayed high levels of E. coli and fecal indicator microorganisms over many years. I used a high-throughput sequencing …

Investigation Of Shocked Basalts From Vargeão Dome And Vista Alegre: Implications For The Search For Life On Mars, Nikol Posnov

Electronic Thesis and Dissertation Repository

Impact craters represent excellent astrobiological targets for planetary exploration missions to Mars. The impact of an asteroid or comet into a crystalline, H₂O-bearing target may result in development of a hydrothermal system and increase the habitability of the substrate for the colonization of endolithic microorganisms. Given that Mars’ surface is covered by cratered basaltic rock, this study investigated target rocks and impact breccias from Vargeão Dome and Vista Alegre impact structures that formed in basalt in the Paraná Basin of Brazil.

Utilizing petrography and micro-X-ray diffraction (μXRD), the degree of shock metamorphism in plagioclase was quantitively determined. Measuring …

Fungi Associated With Herbaceous Plants In Coastal Northern California, Greg Huffman

Natural Sciences and Mathematics | Biological Sciences Master's Theses

The presence of fungal species associated with herbaceous plants was monitored in coastal Marin County, California, USA. The research involved a combination of field sampling surveys and data collection using a stratified random design, pathogen identification through microbiological and molecular analysis, and descriptive analysis and ordination of results. A total of two years of repeated sampling (four times a year) was organized to allow for the detection of seasonal differences in pathogen presence on aerial plant parts. The objective of this study was to identify microbial species present on herbaceous plants using ITS1 sequence analysis. Throughout March of 2018 to …

Proteomic Analysis Of Mycobacteriophage Crimd, William Moeller

Undergraduate Honors Theses

Bacteriophages represent a large portion of the biomatter on our planet, and many of them have yet to be fully characterized. Here we discuss the proteomic analysis of a particular Bacteriophage, Mycobacteriophage CrimD. This phage was discovered on the Campus of William & Mary and has had its genome characterized. We took the next logical step of proteomic analysis.

In our analyses we made use high pressure liquid chromatography paired with linear ion trap mass spectrometry to analyze the proteome of CrimD at specific time points after the infection of its host, Mycobacterium smegmatis. Additionally, we used nanospray ionization with …

Developing A Microdialysis Sampling-Based Biofilm/Macrophage Co-Culture Model, Alda Diaz Perez

Graduate Theses and Dissertations

The host immune system and bacterial cells are known to interact during the human lifetime. Bacteria secrete a wide variety of signaling molecules, known as quorum sensing (QSC) molecules, that modulate the host immune system. While immune-biofilm interactions involve this chemical signaling network, the mechanisms through which this occurs are not well understood. This work aimed to develop a new method that can be used not only in vitro settings but also in vivo. The microdialysis sampling technique has widely been used in in vitro and in vivo settings in humans, mice, and rats for the collection of neuropeptides, cytokines, …

Physiological Constraints, Mechanisms, And Mineral Transformations Of Iron Reduction In Hyperthermophilic Crenarchaea, Srishti Kashyap

Doctoral Dissertations

Dissimilatory iron reduction by hyperthermophilic archaea occurs in many geothermal environments and typically relies on microbe-mineral interactions that transform various iron oxide minerals. However, the kinds of iron oxides that can be used, growth rates, extent of iron reduction, and the mineral transformations that occur due to this metabolism are poorly understood. This dissertation improves our fundamental understanding of the physiological mechanisms and mineral transformations of hyperthermophilic iron reduction using two model crenarchaea, Pyrodictium delaneyi and Pyrobaculum islandicum. Using growth yields and metabolite production rates, we demonstrated that a broad range of Fe(III) (oxyhydr)oxides of variable thermodynamic stability was …

Evaluating The Role Of The Stringent Response Mechanism In Clostridioides Difficile Survival And Pathogenesis, Astha Pokhrel

Chemistry & Biochemistry Theses & Dissertations

The human pathogen Clostridioides difficile is increasingly tolerant of multiple antibiotics and causes infections with a high rate of recurrence, creating an urgent need for new preventive and therapeutic strategies. The stringent response, a universal bacterial response to extracellular stresses, governs antibiotic survival and pathogenesis in diverse organisms but has not previously been characterized in C. difficile. This dissertation explores the ability of C. difficile to mount the stringent response. The bacteria encode a full-length, canonical bifunctional Rel/Spo Homolog or RSH enzyme. C. difficile RSH is incapable of utilizing GTP as a substrate but readily synthesizes putative 5’-pGpp-3’ alarmones. …

The C. Neoformans Cell Wall: A Scaffold For Virulence, Christine Chrissian

Dissertations, Theses, and Capstone Projects

Cryptococcus neoformans is a globally distributed opportunistic fungal pathogen and the causative agent of life threatening cryptococcal meningoencephalitis in immunocompromised individuals, resulting in ~180,000 deaths each year worldwide. A primary virulence-associated trait of this organism is the production of melanin. Melanins are a class of diverse pigments produced via the oxidation and polymerization of aromatic ring compounds that have a characteristically complex, heterogenous, and amorphous structure. They are synthesized by representatives of all biological kingdoms and share a multitude of remarkable properties such as the ability to absorb ultraviolet (UV) light and protect against ionizing radiation. Melanin production in fungi …

Sustainable Bioproduction By Rhodopseudomonas Palustris Tie-1 Through Metabolic Engineering, Wei Bai

McKelvey School of Engineering Theses & Dissertations

The heavy reliance of the petroleum industry for raw material and the rising atmospheric CO2 caused by this reliance have driven the research and development of sustainable alternatives. Microbial production of chemicals, such as fuel and plastic, has been viewed as a feasible method. The wide selection of substrates by microbes enables them to produce chemicals using naturally abundant material or industrial waste, such as CO2, making the production sustainable. Compared to the model organisms such as Escherichia coli, Saccharomyces cerevisiae, many non-model organisms have a broader selection for carbon, electron, and nitrogen sources, making them great candidates for sustainable …

Possibilities & Potential Of Perennial Wheat: A Comparison Of Arbuscular Mycorrhizal Fungi Diversity And Abundance Between Winter Wheat And Kernza, Tess Noble Strohm

Senior Projects Spring 2021

In an effort to harness the benefits of perenniality on soil health, a perennial wheatgrass called Kernza (Thinopyrum intermedium) has been developed for commercial use at the Land Institute in Salina, Kansas. The effects of a cultivar of Kernza intended for the Hudson Valley, NY were examined in this study using Arbuscular Mycorrhizal fungi (AMF) as an indicator of soil health. AMF are an obligate symbiotic fungi known to provide physical and biological benefits to soil and plant systems. Fields containing one and four year old Kernza, as well as a field of an annual winter wheat were sampled to …

Assaying Bacillus Amyloliquefaciens Isolates 1ba And 1d3 For Biosurfactant Production And Utilization Of Petroleum Hydrocarbons And Phenolic Acids, Pavan Kulkarni

Electronic Theses and Dissertations

Several Bacillus amyloliquefaciens isolates obtained from wheat residue have been studied as biological agents to control wheat diseases. Notable traits of isolates 1BA and 1D3 include growth with high salt (10% NaCl), at temperatures up to 50°C and over a wide pH range. BIOLOG Gen III plates were used to study and further characterize Bacillus amyloliquefaciens 1BA and 1D3. Both isolates showed tolerance to high salt concentration supporting previous studies. They also grew in the presence of lithium chloride, potassium tellurite, and sodium bromate. Both isolates grew at pH 5, with almost identical carbon source utilization fingerprints. However, D-serine, quinic …

A Snapshot Of Ancient Microbial Life: Microorganisms And Organic Compounds In Primary Fluid Inclusions In Bedded Halite, Neoproterozoic Browne Formation Of Central Australia, Sara I. Schreder-Gomes

Graduate Theses, Dissertations, and Problem Reports

Modern shallow brine environments contain an abundance of microorganisms. Microorganisms, mineral crystals, and air bubbles can be trapped with those brines in primary fluid inclusions in bedded halite as it grows in shallow saline surface waters. Primary fluid inclusions and their contents can be preserved, unaltered, for millions of years.

The ~830 million-year-old Browne Formation of central Australia contains intervals of bedded halite with unaltered primary fluid inclusions. Intervals of bedded halite were sampled in the Empress 1A core from ~1480 m – 1520 m depths. Here, I used petrography to describe suspect microorganisms and organic compounds that were trapped …

Comparing Capabilities Of Shewanella Oneidensis Mr-1 And The Microbial Community Of Iron Caves To Reduce Fe(Iii), Aaron Douglas Pham

Williams Honors College, Honors Research Projects

Caves are generally formed by the erosion and/or dissolution of rock and its subsequent removal by water. Iron ore caves (IOCs) form despite being hosted by relatively insoluble and weathering-resistant rock. Due to the discovery of a microbial community behind the walls of these caves, it was hypothesized that these bacteria could be responsible for speleogenesis. Iron ore exists in an oxidized (Fe(III)) state, but reduced (Fe(II)) form is soluble. It was further reasoned that the bacteria might be able to reduce Fe(III) through direct metabolic activity, which uses iron as an electron acceptor. Here we show that cave microorganisms …

Modeling Stromatolite Formation With Diffusion-Limited Aggregation, Laura E. Stevens

Graduate Student Theses, Dissertations, & Professional Papers

Stromatolites, microbialites, and other microbially induced sedimentary structures exist in the rock record as far back as 3.6 billion years ago and continue to form in the present day. Better characterizing these structures and better understanding how they form is crucial in distinguishing these biosignatures from similar, abiotic structures, which can help us to understand the conditions of early Earth and early Mars. To that end, I have modified DLA 3D EXT, an open-source stromatolite modeling program, to more closely reflect the process of microbial trapping-and-binding by filamentous microbes in a calcite-precipitating hot spring system. This modified program includes a …

Utilization Of Paenibacillus Polymyxa In The Recovery Of Lithium Bearing Minerals, Diana Bullen

Dissertations, Master's Theses and Master's Reports

In the global transition to green energy in the transportation and power production sectors, lithium has emerged as a viable solution, and crucial component, for the effective storage of renewable resources. To avoid further degradation of the land due to mining for virgin material, methods focused on recovering lithium must be developed. This research project seeks to explore a new way to recover lithium by using the bacterium Paenibacillus polymyxa. The bacteria were grown and then applied to the lithium bearing mineral spodumene. Settling velocity profiles were constructed for different treatments of spodumene. It was found that the spodumene …