Biochemistry, Biophysics, and Structural Biology Commons^™

The Role Of Mitochondrial Omi/Htra2 Protease In Protein Quality Control And Mitophagy, Camilla Ambivero

Electronic Theses and Dissertations

Omi/HtrA2 is a mitochondrial serine protease with a dual and opposite function depending on its subcellular localization. Most of the previous studies focused on Omi/HtrA2’s pro-apoptotic function when the protein is released to the cytoplasm. It is becoming apparent that the main function of Omi/HtrA2 is within the mitochondria, where it has a pro-survival role. However, its mechanism is still poorly understood. To this end, we used the yeast two-hybrid system to dissect the Omi/HtrA2 pathway by identifying novel interactors and substrates. Our studies revealed a novel function of Omi/HtrA2 in the regulation of a deubiquitinating (DUB) complex. In addition …

The Cytopathic Activity Of Cholera Toxin Requires A Threshold Quantity Of Cytosolic Toxin., Carly Bader

Electronic Theses and Dissertations

Cholera toxin (CT), secreted from Vibrio cholerae, causes a massive fluid and electrolyte efflux in the small intestine that results in life-threatening diarrhea and dehydration which impacts 3-5 million people per year. CT is secreted into the intestinal lumen but acts within the cytosol of intestinal epithelial cells. CT is an AB5 toxin that has a catalytic A1 subunit and a cell binding B subunit. CT moves from the cell surface to the endoplasmic reticulum (ER) by retrograde transport. Much of the toxin is transported to the lysosomes for degradation, but a secondary pool of toxin is diverted to the …

Characterization Of Motility Alterations Caused By The Impairment Of Dynein/Dynactin Motor Protein Complex, Swaran Nandini

Electronic Theses and Dissertations

Transport of intracellular cargo is an important and dynamic process required for cell maintenance and survival. Dynein is the motor protein that carries organelles and vesicles from the cell periphery to the cell center along the microtubule network. Dynactin is a protein that activates dynein for this transport process. Together, dynein and dynactin forms a motor protein complex that is essential for transport processes in all the vertebrate cells. Using fluorescent microscope based live cell imaging techniques and kymograph analyses, I studied dynein/dynactin disruptions on the intracellular transport in two different cell systems. In one set of experiments, effects of …

Bone Morphogenetic Protein-7 (Bmp-7) Polarizes Monocytes Into M2 Macrophages, Crystal Rocher

Electronic Theses and Dissertations

Atherosclerosis is an inflammatory disease in which an accumulation of fatty acids and cholesterol occurs to form a plaque in small and large arteries. Monocyte polarization to classic M1 macrophages or alternative M2 macrophages is an important area of research that can determine the severity of disease progression. BMP-7 is a key growth factor responsible for directing differentiation of mesenchymal stem cells into brown fat cells, suggesting a role of BMP-7 in cellular plasticity; however, its role in monocyte polarization is yet to be revealed. In the current study, we hypothesize that monocyte treatment with BMP-7 will significantly result in …

Delineating Key Genetic Components On Linear Plasmid 36 That Contribute To Its Essential Role In Borrelia Burgdorferi Mammalian Infectivity., Tisha Choudhury

Electronic Theses and Dissertations

The spirochete Borrelia burgdorferi is the etiologic agent of Lyme disease. This pathogen has a complex enzootic life cycle that involves passage between the tick vector (Ixodes scapularis) and various vertebrate hosts with humans being inadvertent hosts. There is a pressing need to study the genetic aspects of the B. burgdorferi infectious cycle and particularly spirochete genes involved in mammalian infectivity so as to develop novel therapeutic and diagnostic strategies to combat Lyme disease. The B. burgdorferi genome is fragmented and comprised of a single 900 kb linear chromosome and multiple linear and circular plasmids. It has been observed that …

Mixed Valence Copper(Cu)/Silica Nanocomposite: Synthesis, Characterization And Systematic Antimicrobial Studies, Mikaeel Young

Electronic Theses and Dissertations

Copper (Cu) compounds are widely used as effective agricultural bactericides. Continuous use of these materials has led to Cu accumulation in soil over time. The United States Environmental Protection Agency (US EPA) is concerned about potential Cu contamination in the environment. Improving biocidal efficacy of Cu is an attractive alternative, allowing reduction of Cu amount per application. In this research, we focused on making watersoluble mixed-valence Copper/Silica composite nanogel (CuSiNG) material. The objective is to improve the efficacy of Cu by manipulating Cu valence states. It has been shown in the literature that Cu (0) and Cu (I) states are …

Immuno-Pcr Detection Of Lyme Borreliosis, Micah Halpern

Electronic Theses and Dissertations

Lyme borreliosis, more commonly referred to as Lyme disease, is the fastest growing zoonotic disease in North America with approximately 30,000 confirmed cases and 300,000 estimated infections per year. In nature, the causative agent of Lyme disease, the bacterium Borrelia burgdorferi, cycles between Ixodes sp. ticks and small mammals. Humans become infected with Lyme disease after being bitten by an infected tick. The primary indicator of a Borrelia burgdorferi infection is a bull’s eye rash typically followed by flu-like symptoms with treatment consisting of a 2-4 week course of antibiotics. If not treated, later stages of the disease can result …

Doxorubicin-Induced, Tnf-Α-Mediated Brain Oxidative Stress, Neurochemical Alterations, And Cognitive Decline: Insights Into Mechanisms Of Chemotherapy Induced Cognitive Impairment And Its Prevention, Jeriel T. Keeney

Theses and Dissertations--Chemistry

The works presented in this dissertation provide insights into the mechanisms of chemotherapy-induced cognitive impairment (CICI or “ChemoBrain”) and take steps toward outlining a preventive strategy. CICI is now widely recognized as a complication of cancer chemotherapy experienced by a large percentage of cancer survivors. Approximately fifty percent of existing FDA-approved anti-cancer drugs generate reactive oxygen species (ROS). Doxorubicin (Dox), a prototypical ROS-generating chemotherapeutic agent, produces the reactive superoxide radical anion (O₂^-•) in vivo. Dox treatment results in oxidation of plasma proteins, including ApoA-I, leading to TNF-α-mediated oxidative stress in plasma and brain. TNF-α elevation in brain …

Understanding Multidrug Resistance In Gram-Negative Bacteria -- A Study Of A Drug Efflux Pump Acrb And A Periplasmic Chaperone Sura, Meng Zhong

Theses and Dissertations--Chemistry

Multiple drug resistance (MDR) has been a severe issue in treatment and recovery from infection.Gram-negative bacteria intrinsically exhibit higher drug tolerance than Gram-positive microbes. In this thesis, two proteins involved in Gram-negative bacterial MDR were studied, AcrB and SurA.

Resistance-nodulation-cell division pump AcrAB-TolC is the major MDR efflux system in Gram-negative bacteria and efficiently extrudes a broad range of substances from the cells. To study subtle conformational changes of AcrB in vivo, a reporter platform was designed. Cysteine pairs were introduced into different regions in the periplasmic domain of the protein, and the extents of disulfide bond formation were …

Structural And Functional Characterization Of Mulitdrug Resistance Transporter And Regulator, Linliang Yu

Theses and Dissertations--Chemistry

Drug resistant bacteria pathogen poses a severe threat to human health. Bacterial drug efflux pumps are transporter proteins involved in the export of antibiotics out of cells. Efflux by transporters is one of the major drug resistant mechanisms. Multidrug efflux pumps can transport multiple classes of antibiotics and are associated with bacteria multiple drug resistance (MDR). Overproduction of these pumps reduces susceptibility of bacteria to a variety of antibiotics. MDR regulators are cytoplasmic proteins that control the expression level of MDR transporters in response to the cellular concentration of antibiotics. This thesis research focuses on three main directions in the …

Determination Of Structural Stabilities Of Metal-Free Porphyrin Cytochrome C, Zinc Cytochrome C, And Cobalt Cytochrome C, Usha K. Tottempudi

Masters Theses

No abstract provided.

Molecular Mechanisms Involved In Anhydrobiosis Of Insect Cells, Diyagama Arachchi Ralalage Dilini Sewwandi Samarajeewa

Masters Theses

Animals possessing tolerance to extreme water stress are termed anhydrobiotes. Many desiccation tolerant organisms respond to water stress by intracellular accumulation of selected sugars such as trehalose and larger macromolecules such as Late Embryogenesis Abundant (LEA) proteins and thereby maintain the cell viability. Evidence indicates that the presence of trehalose and Late Embryogenesis Abundant (LEA) proteins may work synergistically to confer cellular protection during drying in eukaryotic cells. We evaluated any increase in cellular desiccation tolerance by expressing different LEA proteins in a non-desiccation tolerant insect cell line Drosophila melanogaster (fruit fly) (Kc167 cells) in the presence of trehalose.

Transgenic …

Critical Functions Specified By The Mll Cxxc Domain Determine Leukemogenic Capacity, Noah Warren Birch

Dissertations

TheMixed Lineage Leukemia(MLL) gene can participate in chromosomal translocations which generate a fusion protein leading to acute leukemia. A better understanding of how MLL fusion proteins contribute to leukemia is necessary in order to develop more effective treatments. In my dissertation project, I investigated the functional role of amino acids within the MLL CXXC domain to determine how specific residues contribute to leukemogenic capacity.

MLL fusion proteins retain the amino-terminal portion of MLL including the CXXC DNA-binding domain while the carboxy-terminal portion is comprised of a fusion partner. The closest homolog of MLL, MLL2 (alternatively named MLL4), also contains a …

Targeting The Notch-1/Igf-1r/Akt Axis In At Orthotopic Model Of Advanced Non-Small Cell Lung Cancer, Shuang Liang

Dissertations

Lung cancer is the leading cause of cancer death in the U.S. and worldwide. The most frequent type of lung cancer is non-small cell lung cancer (NSCLC). NSCLC is mostly diagnosed at advanced stages (stage IIIB 18% of cases, stage IV 40% of cases) due to the lack of effective early detection methods. Thus, the discovery of alternative therapeutic strategies is of extreme importance.

Others and we have previously found that Notch signaling plays a crucial role in NSCLC. Our preliminary results indicate that Notch-1 provides necessary survival signals to NSCLC cells by positively regulating IGF-1R to activate the Akt-1 …

Biochemical, Structural, And Drug Design Studies Of Multi-Drug Resistant Hiv-1 Therapeutic Targets, Tamaria Grace Dewdney

Wayne State University Dissertations

Protein point mutations acquired as a mechanism of survival against therapeutics cause structural changes that effect protein function and inhibitor binding. This work investigates the structural mechanisms that lead to multi-drug resistance to HIV-1 protease and integrase inhibitors.

Proper proteolytic processing of the HIV-1 Gag/Pol polyprotein is required for HIV infection and viral replication. This feature has made HIV-1 protease an attractive target for antiretroviral drug design for the treatment of HIV-1 infected patients, thus the development of drug resistance has arisen as a major therapeutic and drug design challenge. To understand the molecular mechanisms leading to drug resistance we …

The Metabolic Transitions Regulated By The Estrogen-Related Receptor (Err) In Drosophila Melanogaster, Yan Li

Theses and Dissertations

In multicellular organism, bioenergetic metabolism is strictly regulated toward efficient generation of ATP. However, in certain situations, such as in limiting oxygen or in the rapidly proliferating system like growing juvenile or cancer cells, organisms apply the metabolic strategy that favors the production of biomass (e.g., nucleotides, amino acids, and lipids) over efficiency of ATP generation. The conserved estrogen-related receptors (ERRs) are master regulators in controlling metabolic homeostasis, and good candidates for mediating the metabolic transition induced by hypoxia and development. First, we investigate how dERR influences hypoxic adaptation in Drosophila melanogaster. We find that dERR is required for a …

The Cave Environment Influencing The Lipid Profile And Hepatic Lipogenesis Of The Fish Ancistrus Cryptophthalmus Reis, 1987 (Siluriformes: Loricariidae), Valquíria Aparecida Alves Bastos, Rodrigo Lopes Ferreira, Daniel Cardoso Carvalho, Marina Lages Pugedo, Luciana De Matos Alves Pinto

International Journal of Speleology

The metabolism of hypogean organisms is frequently molded by the cave environment traits, especially food scarcity. The aim of the present work was to evaluate the influence of such environment on lipid composition and hepatic lipogenesis in the fish Ancistrus cryptophthalmus. For this, the species was compared to an epigean population of the same species. A greater accumulation of total lipids was observed in the cave-dwelling fish (18.36 g/100 g tissue) compared to the surface fish (14.09 g/100 g tissue). The muscle fatty acid profile also varied between the populations. Arachidonic acid was only detected in the epigean fish, while …

Proteolytic Processing Of The Amyloid Precursor Protein During Apoptosis And Cell Cycle: Implications For Alzheimer's Disease, Tina N. Fiorelli

USF Tampa Graduate Theses and Dissertations

Alzheimer's disease is characterized by the presence of amyloid plaques, made up primarily of Aϐ peptides, and neurofibrillary tangles, containing hyperphosphorylated tau. Aϐ is generated by sequential proteolysis of the amyloid precursor protein (APP) by beta and gamma secretases. The leading hypothesis of Alzheimer's disease pathogenesis is the amyloid cascade hypothesis, which suggests that amyloid is central to the disease process. However, tau pathology correlates more closely with cognitive dysfunction and follows a predictable anatomical course through the brain. We hypothesize that if Aϐ is upstream of tau pathology and tau pathology follows this predictable course through the brain, Aϐ …

Reaction Enthalpy And Volume Profiles For Excited State Reactions Involving Electron Transfer And Proton-Coupled Electron Transfer, William Antonio Maza

USF Tampa Graduate Theses and Dissertations

Electron transfer, ET, and proton-coupled electron transfer, PCET, reactions are central to biological reactions involving catalysis, energy conversion and energy storage. The movement of electrons and protons in either a sequential or concerted manner are coupled in a series of elementary reaction steps in respiration and photosynthesis to harvest and convert energy consumed in foodstuffs or by absorption of light into high energy chemi-cal bonds in the form of ATP. These electron transfer processes may be modulated by conformational dynamics within the protein matrix or at the protein-protein interface, the energetics of which are still not well understood. Photoacoustic calorimetry …

Biochemical Aspects Of The Thermal Sensitivity And Energy Balance Of Polar, Tropical And Subtropical Teleosts, Eloy Martinez

USF Tampa Graduate Theses and Dissertations

The maintenance of a functional energy balance in ectothermic fauna could be challenging in a thermally disparate environment. Biochemical adaptations at the enzyme and membrane levels allows for a set compensatory mechanism that allow the individual to maintain an energetic surplus, thus allocating energy for growth and reproduction. The present work describes how the energetic machinery in the cell, particularly the mitochondrion, could be affected by temperature changes. More specifically, this work aimed to determine how environmental temperature affects the mitochondria energetic performance of fishes from disparate thermal regimes.

Mitochondrial ATP production efficiency was evaluated in fishes from polar, tropical …