Biochemistry, Biophysics, and Structural Biology Commons^™

Genetic And Genomic Analyses Of Bacterial Responses To Different Stress Environments, Sakshi Rampal

Graduate Theses and Dissertations

Bacteria encounter a plethora of environmental stresses and have evolved different mechanisms to recognize and respond to various harmful conditions. Understanding and elucidating common themes as well as unique aspects of the molecular mechanisms underlying stress adaptation is important and can provide valuable strategies for applications. This study focuses on stress responses in three different bacteria, namely, Acidothermus cellulolyticus, Mycobacterium smegmatis and Escherichia coli. The thermophilic and acidophilic organism A. cellulolyticus was used as a model system to understand the effects of lignin phenolic acids on cellulolytic bacteria. Lignin phenolic acids pose a significant challenge to microbial deconstruction of lignocellulosic …

Ca2+ - Induced Structural Change Of Multi-Domain Collagen Binding Segments Of Collagenases Colg And Colh From Hathewaya Histolytica, Christopher Eric Ruth

Graduate Theses and Dissertations

Hathewaya histolytica, previously renamed as Clostridium histolyticum, secretes at least two collagenases, ColH and ColG, that allow for degradation of extracellular matrices of animal tissue. Hathewaya histolytica virulence factors are proposed to undergo domain rearrangement upon secretion from the bacteria to the host. In order to accomplish this, collagenases seek the least ordered regions in collagen to efficiently disassemble the fibril. Two types of domains, Polycystic Kidney Disease-like (PKD) and Collagen Binding Domain (CBD), direct the collagenases ability to disassemble the fibril. Calcium dependent structural change have been reported to increase in thermal stability and in tighter collagen binding for …

Characterization Of A Variant Of Tuberous Sclerosis Complex 2 And Its Interaction With Rheb, Sowmya Sivakumar

Graduate Theses and Dissertations

Protein-protein interactions are vital in maintaining proper function and homeostasis in cells. Some signaling pathways are regulated by G-proteins that work like switches to activate and deactivate pathways. Mutations in these proteins, their effectors or the interaction between proteins may cause dysregulation of signals that can lead to many diseases.

Rheb, Ras homology enriched in brain, is a Ras family GTPase that is vital in regulation of the mTOR (mammalian target of rapamycin) pathway that signals cell proliferation and growth. Due to the low intrinsic GTPase activity of Rheb, a GTPase activating protein (GAP), Tuberous Sclerosis Complex 2 (TSC2) down …

State Dependent Function And Dynamics In Cerebral Cortical Networks, Leila Fakhraei

Graduate Theses and Dissertations

Cerebral cortex exhibits vigorous ongoing, internal neural activity even with no sensory input is present or the animal is minimally engaged in a task or behavior. This internal ongoing activity is not static; the ‘cortical state’ varies ranging from synchronous and highly correlated activity to asynchronous and weakly correlated neural activity. The main goal of the work presented here is to understand how changes in cortical states effect several aspects of cortical function and dynamics.

To meet this goal, we did three separate projects. First, we compared the predictability of neuronal network dynamics across cortical states in somatosensory cortex of …

Involvement Of The Ino80 Complex In Chromosome Segregation, Jesus Moreno

Graduate Theses and Dissertations

Chromatin remodeling complexes are multi-protein complexes that regulate the dynamics of the nucleosomes in the genome. The INO80 chromatin remodeling complex participates in varied biological processes such as: transcription, DNA repair, DNA replication and chromosome integrity. It catalyzes the eviction of the H2A.Z variant histone as well as whole nucleosome eviction. This complex is comprised of 15 subunits and the contribution of each to chromosome segregations remains unknown. To evaluate the contribution of each subunit to chromosome segregation, we tested deletion mutants of the non-essential subunits for DNA content and benomyl sensitivity. Also, we assessed members of the SWR1 and …

Mitochondrial Mrna Translation Is Required For Maintenance Of Oxidative Capacity, David Lee

Graduate Theses and Dissertations

Oxidative metabolism is required to produce adequate energy to sustain human life. A primary example of deteriorating oxidative capacity is seen in the cardiac musculature during chronic heart failure. This suggests that by improving oxidative potential, chronic heart disease could be mitigated and one approach to accomplish this may be through targeting the mt-mRNA translation system. Purpose: This investigation’s purpose was to characterize disruptions in mt-mRNA translation machinery in multiple forms of cardiomyopathy and to determine if mitochondrial mRNA translation initiation factor (mtIF2) is necessary to maintain oxidative capacity in cardiomyocytes. Methods Using a combination of animal and cell culture …

Engineering The Structure Of The Human Acidic Fibroblast Growth Factor To Enhance Its Stability And Cell Proliferation Activity, Julie Davis Eberle

Graduate Theses and Dissertations

Human acidic fibroblast growth factor (hFGF1) is a protein well known for its role in cell growth and differentiation. To elicit these cell-signaling processes, hFGF1 non-selectively binds to any one of the seven cell surface hFGF receptor isoforms. Due to its significant involvement in tissue repair activity, hFGF1 is a prime candidate for novel wound healing therapeutics. However, one drawback toward its use as a novel wound healing therapeutic is the poor inherent thermal stability of hFGF1, as it has been found to unfold near physiological temperature. The cause of this instability is strong electrostatic repulsion created by a dense …

Rapid And Sensitive Detection Of Escherichia Coli O157:H7 Using A Qcm Sensor Based On Aptamers Selected By Whole-Bacterium Selex And A Multivalent Aptamer System, Xiaofan Yu

Graduate Theses and Dissertations

Escherichia coli O157:H7 is one of the top five pathogens contributing to foodborne diseases, causing an estimated 2,138 cases of hospitalization in the US each year. The extremely low infectious dose demands for more rapid and sensitive methods to detect E. coli O157:H7. The objective of this study is to select aptamers specifically binding to E. coli O157:H7 using whole-bacterium SELEX (Systematic Evolution of Ligands by Exponential Enrichment) and to create a multivalent aptamer system by rolling circle amplification (RCA) with the selected aptamer sequence for sensitive detection of E. coli O157:H7 using a quartz crystal microbalance (QCM) sensor. Briefly, …

Characterization Of Bacteriorhodopsin And Halorhodopsin Reconstituted In Lipid Bilayer Membranes, Joel Domkam Kamwa

Graduate Theses and Dissertations

Motivated to produce electricity with photon activated ion pumps, the main purpose of this work was to characterize the photosynthetic membrane proteins bacteriorhodopsin (proton pump) and halorhodopsin (chloride pump). The proteins were re-suspended in lipid bilayers. For this work, an experimental set-up was built which included: chambers for lipid bilayer formation and characterization, lasers for ion pump activation, and an AxoPatch electrophysiology system for small photocurrent measurement. Lipid bilayer membranes were formed using mostly folding method: folding two monolayers together. The membranes were characterized by their resistance, capacitance, and generated photocurrent. Photocurrent was generated upon illumination of lipid-protein membranes with …

Optimizing Genetic Manipulation Of Methanogens Through Faster Cloning Techniques, Merrisa Jennings

Biological and Agricultural Engineering Undergraduate Honors Theses

Methanogenesis is the biological production of methane. Only anaerobic archaea known as methanogens are capable of such a metabolic feat. They have strict living conditions and substrate sources which determine their rate of metabolism. This is of particular importance from a greenhouse gas reduction perspective or biogas capturing perspective. One of the best ways to optimize methanogen methane production is via genetic manipulation. The current procedures are timely though, therefore a faster cloning processes should be developed. The objective of this study was to optimize a premade genetic transformation kit known as the Gibson Kit. The Gibson Kit was supposed …

Microbiome Of Commercial Broilers Through Evisceration And Immersion Chilling, John A. Handley

Graduate Theses and Dissertations

The United States poultry industry generated 38.6 billion pounds (17,500 metric ton) of meat in 2014 which averaged to 121 pounds (55 kg) per individual of the U.S that same year. Of that meat generated by the poultry industry, an estimated 1 million cases of Salmonellosis will occur. Out of the 1 million cases approximately 40, 000 to 50,000 will be confirmed cases by the CDC. Recently, the USDA has requested changes in the inspection process and are currently allowing processors more freedom to utilize innovation to drive the increase in safer and more desirable foods. The new standards set …

Unravelling The Layers Of Cell Wall Synthesis And Function In Rice, Ritu Mihani

Graduate Theses and Dissertations

The plant cell wall is of critical importance to plant growth and survival, functioning in maintaining structural integrity, supporting cell expansion, and acting as the first line of defense in response to biotic and abiotic stresses. The major components of the cell wall are cellulose, hemicelluloses, lignin, and pectin. Recent focus on the transcriptional machinery regulating cell wall biosynthesis in plants has revealed many key transcription factors responsible for orchestrating cell wall deposition. However, many of these TFs act redundantly and work coherently with a suite of TFs to activate the cell wall biosynthetic machinery. Heterologous expression of TFs is …

Role Of Incompatibility Group 1 (Inci1) Plasmid-Encoded Factors On Salmonella Enterica Antimicrobial Resistance And Virulence, Pravin Raghunath Kaldhone

Graduate Theses and Dissertations

Foodborne illnesses are a leading cause of infectious diseases in the world. Among enteric organisms Salmonella is a key pathogen. It’s high prevalence in poultry and other food-animal sources make it imperative to study. Salmonella has the ability to modify its genetic content with help of mobile genetic elements such as plasmids. Incompatibiltiy group 1 (IncI1) plasmids are commonly reported in Salmonella. This study evaluates role on IncI1 plasmids in antimicrobial resistance and virulence in Salmonella. Genetic determinants of resistance and virulence are noted among our IncI1-containing Salmonella isolates. These genetic elements are also transferable and reported to carry respective …

Developing Algorithms For Quantifying The Super Resolution Microscopic Data: Applications To The Quantification Of Protein-Reorganization In Bacteria Responding To Treatment By Silver Ions, Sai Divya Challapalli

Graduate Theses and Dissertations

Histone-like nucleoid structuring proteins (HNS) play significant roles in shaping the chromosomal DNA, regulation of transcriptional networks in microbes, as well as bacterial responses to environmental changes such as temperature fluctuations. In this work, the intracellular organization of HNS proteins in E. coli bacteria was investigated utilizing super-resolution fluorescence microscopy, which surpasses conventional microscopy by 10–20 fold in spatial resolution. More importantly, the changes of the spatial distribution of HNS proteins in E. coli, by addition of silver ions into the growth medium were explored. To quantify the spatial distribution of HNS in bacteria and its changes, an automatic method …

Understanding Intracellular Redox Regulation In Methanogens: Characterization Of The Components And Targets Of The Nadph-Dependent Thioredoxin System From Methanosarcina Acetivorans, Addison Clark Mccarver

Graduate Theses and Dissertations

All cells have a reduced intracellular environment. In the presence of oxygen, the non-specific oxidation of intracellular components leads to the production of reactive oxygen species (ROS) within cells leading to oxidative stress. During oxidative stress labile cofactors (e.g. Fe-S clusters) are lost and deleterious disulfide bonds are formed within proteins. Intracellular redox maintenance systems are used to direct reducing equivalents towards the repair of oxidatively-damaged proteins. The thioredoxin system is the ubiquitous intracellular redox system, found in virtually all species. The canonical thioredoxin system is comprised of a NADPH-dependent thioredoxin reductase (TrxR) that functions to reduced thioredoxin (Trx). Although …

Cellular Mechanisms Of Ionoregulation In The Gill Of Japanese Medaka And Rainbow Trout, Rebecca Jo Bollinger

Graduate Theses and Dissertations

Euryhaline fishes are capable of adapting to a wide range of salinities such as freshwater, brackish water or seawater. Through the combined effort of the gill, kidney and intestine, they are able to osmoregulate to maintain a constant internal hydromineral balance. As the gill is in direct contact with the external environment, it is continuously working to maintain ion and acid/base balance, gas exchange and eliminate nitrogenous waste. Fish in freshwater are subjected to osmotic water gain and diffusional ion loss across the gill and experience the opposite in seawater. Therefore, the gill exhibits extreme plasticity when experiencing a change …

Determination Of The Effects Of Different Maillard Reaction Products On The Taxonomic Composition Of The Gut Microbiota, Nesreen Hamdan Aljahdali

Graduate Theses and Dissertations

The Maillard Reaction (MR) is a non-enzymatic chemical reaction which results in linkage between the amino group of amino acids and the carbonyl group of reduced sugars. This reaction generates Maillard reaction products (MRPs) which are not present naturally in foods, and are responsible for a range of colors, odors, flavors, and other sensory properties. Conflicting reports of MRPs impacts on human health are probably due to the fact that bioconversion of these digestible molecules by the gut microbiota has been marginally taken into account. This study aimed to determine the effects of different MRPs on rodent’s gut microbiota through16S …

Detection Of Survival And Proliferation Of Sulfate Reducers Under Simulated Martian Atmospheric And Soil Conditions, Sergio Mosquera Mora

Graduate Theses and Dissertations

Numerous studies have tried to determine the survivability and proliferation of microorganisms under simulated Martian conditions. Furthermore, most of them have been focused on the ability of these microbes to cope with high brines’ salt (NaCl) concentrations inherent of the Martian surface. However, there are not studies related to the ability of bacteria to survive on subsurface environments that have increasing concentrations of sulfate compounds. For this research, a group of microorganisms known as sulfate-reducing bacteria or simply sulfate reducers were chosen due to their ability to use sulfate compounds as terminal electron acceptors to produce metabolic energy, their tolerance …

Piglet Gut Microbiota Responses To Exposure To Outdoor Simulated Environment And Formula Feeding, Nguyen Vo

Graduate Theses and Dissertations

Several lines of evidence suggest that early-life gut microbiota composition is a crucial determinant of the susceptibility to diseases later in life. Understanding the evolution of early-life gut microbiota and critical factors that can modify this microbial community will espouse the prevention or reversion of health risk originating from dysbiosis of the gut microbiota in the early stage. In this research, we hypothesized that alterations in the environment (simulation of rural conditions by soil exposure) and feeding mode (breastmilk versus formula milk) will have significant impacts on the establishment of the gut microbiota in early life. At first, in literature …

Comprehensive Assessments Of The Genetic Determinants In Salmonella Typhimurium For Fitness Under Host Stressors: Oxidative Stress And Iron Restriction, Sardar Abdullah

Graduate Theses and Dissertations

Salmonella is an intracellular pathogen that infects a wide range of hosts. The infected host utilizes reactive oxygen species (ROS) and iron-restriction to eliminate the pathogen. We used proteogenomics to determine the candidate genes and proteins that have a role in resistance of S. Typhimurium to H2O2. For Tn-seq, a highly saturated Tn5 library was grown in vitro under either 2.5 (H2O2L) or 3.5 mM H2O2 (H2O2H). We identified two sets of overlapping genes that are required for resistance of S. Typhimurium to H2O2L and H2O2H, and the results were validated via phenotypic evaluation of 50 selected mutants. The enriched …

Linear Dna-Linked Nanoparticle Building Blocks (Nblocks) For Modular Self-Assembly Of Nanostructures, Jakob Thomas Hockman

Graduate Theses and Dissertations

Controlling the shapes and sizes of nanomaterials often enables controlling their properties for certain applications. The most promising methods for controlling the shapes and sizes of nanostructures use base-pairing between complementary DNA strands to self-assemble nanostructures from DNA and nanoparticles. DNA Brick-based self-assembly is a particularly useful method for creating DNA nanostructures. It offers a large amount of control over the final shapes and sizes because it uses building blocks that are anisotropic and have predictable geometry. However, this control has not been extended to the self-assembly of nanostructures from nanoparticles. Applying DNA Brick based self-assembly to the self-assembly of …

Membrane Surface Engineering For Biochemical Applications, Anh T. Vu

Graduate Theses and Dissertations

Synthetic membranes have been frequently used for many fields, such as, the food and beverage, biopharmaceutical, and biofuel industries. In the beer industry, microfiltration frequently suffers from fouling due to the interaction between different species. It is shown that polyphenols can form cross-links with protein molecules, forming insoluble aggregates. However, by adding an optimal amount of polysaccharides these aggregates can be disrupted thus reducing fouling by the aggregates. Confocal laser scanning microscopy (CLSM) is a powerful technique to locate the foulants inside the wet membrane in order to understand more about the behavior of fouling in microfiltration.

Membrane surface modification …

Membranes For Food And Bioproduct Processing, Alexandru Marius Avram

Graduate Theses and Dissertations

Modified membranes for process intensification in biomass hydrolysis

Production of biofuels and chemicals from lignocellulosic biomass is one of the leading candidates for replacement of petroleum based fuels and chemicals. However, conversion of lignocellulosic biomass into fuels and chemicals is not cost effective compared to the production of fuels and chemicals from crude oil reserves. Some novel and economically feasible approaches involve the use of ionic liquids as solvents or co-solvents, since these show improved solvation capability of cellulose over simple aqueous systems. Membranes offer unique opportunities for process intensification which involves fractionation of the resulting biomass hydrolysate leading to …

Removal Of Endocrine Disrupting Compounds Using Membrane Bioreactor, Mohanad Ali Abdulsahib Kamaz

Graduate Theses and Dissertations

The presence of endocrine disrupting compounds (EDCs) and pharmaceutically active compounds (PhAC) such as pesticides, personal care products, antibiotics and pharmaceutical compounds, in sewage, industrial, and domestic waters has extensively become the major concern for health and environmental organizations. These compounds have the ability to interact with mammalian endocrine system and disrupting their functions. The traditional activated sludge processes are designed to degrade solids, organic carbon and nitrogen loading. Although several treatment steps in a wastewater treatment plant can contribute to partial removal of EDCs, effective removal has been a challenge due to their resistant chemical and biological degradation and …

Molecular And Biochemical Studies Of Several Novel Estrogen Receptor Alpha-Interacting Proteins In Breast Cancer Cells, Ahmed Edan Dhamad

Graduate Theses and Dissertations

Breast cancer is the second leading cause of cancer-related death in women, and approximately 70% of incidences are estrogen receptor (ER)-positive breast cancer. ERα and its interacting proteins play a key role in the development and progression of breast cancer. However, how ERα regulates its target gene expression and hence cell proliferation is not fully understood. To enhance our understanding of the molecular mechanism by which ERα regulates gene expression, we used a quantitative proteomic method to identify cellular proteins that interact with ERα. The first group of proteins that were identified to associate with ERα are heat shock proteins …

Structural Characterization Of Bacterial Collagenases, Ryan Bauer

Graduate Theses and Dissertations

Clostridium histolyticum secretes collagenases ColG and ColH to cause extensive tissue destruction during myonecrosis. The collagenases are multi-domain enzymes consisting of a N-terminal collagenase module, s1, polycystic kidney disease (PKD)-like domains (s2 in ColG; s2a and s2b in ColH) and collagen-binding domains (CBD) (s3a and s3b in ColG; s3 in ColH). The individual CBD and PKD-like domains chelate calcium to modulate stability and domain rearrangement. Though used by bacteria to break down collagen in the extracellular matrix during infection, therapeutic use of the enzyme to break down excess connective tissue has been approved by the FDA. Meanwhile, the use of …

Phylogenetic Diversity Of The Bacterial Communities In Craft Beer, Lindsey Rodhouse

Graduate Theses and Dissertations

The craft beer industry is increasing in popularity in the United States. The craft brewing process typically does not use a pasteurization step, therefore the boiling process is the primary critical control step. Any microorganisms introduced after boiling, or those that are not killed during boiling, are likely to participate in fermentation and persist in the final product. Previous culture-based studies have isolated bacteria and yeast from craft beers at specific time points, but little research has been done on the process as a whole. The objectives of this research are to (1) track bacteria development throughout the brewing process …

Characterization Of A Tuberous Sclerosis Complex 2 Variant And Its Interaction Involving The Ras-Related Protein Rheb, Nosaiba Shokr

Graduate Theses and Dissertations

Structure-function relationships of any complex underlie the molecular details of the biological interactions. Rheb, Ras Homology Enriched in Brain, is a Ras-related protein, and it is genetically identified as a molecular switch. Rheb is regulated by cycling between the biologically active GTP and inactive GDP-bound forms. This regulation is partially controlled by an interaction with Tuberous Sclerosis Complex2 (TSC2), a GTPase activating protein (GAP). Upon interaction, TSC2 stimulates Rheb GTP hydrolysis and diminishes the mammalian target of rapamycin (mTOR) pathway. The mTOR pathway is involved in proteins synthesis, cell cycle, and signaling. Mutation in TSC2 causes abnormal activation of Rheb …

Genome Wide Association And Next Generation Sequencing Approaches To Map Determinants Of Ascites In Broiler Chickens, Shatovisha Dey

Graduate Theses and Dissertations

These studies have investigated different candidate genomic regions for their contributions to ascites in broilers. Ascites syndrome is a manifestation of idiopathic pulmonary arteriole hypertension that concerns the poultry industry worldwide. Investigations have demonstrated the disease to be genetically regulated and to exhibit moderate to high heritabilities. Although previous studies have indicated a few chromosomes to be involved with ascites, no genes have been identified to date with direct links to the disease. This dissertation presents a collection of studies that determine the genomic and genetic interactions for regions on chromosome 2 and 9 for ascites phenotypes in broiler chickens. …

A Numerical Study Of The Interaction Between One Dimensional Carbyne Chain And Single Stranded Dna, Zeina Salman

Graduate Theses and Dissertations

resolution at the single nucleotide level when developing DNA sequencers. The purpose of this research was to numerically study the electrical properties associated with the interaction between 1D carbon chain, known as carbyne, and ssDNA. First, the electrical properties of the carbyne chain were calculated. Second, the electrical properties of the carbyne chain were calculated in the presence of different ssDNA bases. Analyzing the differences between the two cases led to determining the effects of these different bases on the electrical properties. The numerical simulation approach conducted in this research was based on the first-principle simulation. The first-principle simulation was …