Life Sciences Commons^™

Expression Analysis Of Micrornas And Microrna-Like Rnas In Aspergillus Flavus-Infected Aflatoxin Resistant And Susceptible Maize Inbred Lines, Amanda Benton Harper

Theses and Dissertations

Corn (Zea mays) is frequently infected by a soil fungal pathogen Aspergillus flavus. The fungus produces aflatoxins, which cause liver cancer. Maize inbred lines that are resistant to infection by A. flavus have been developed, and these inbred lines provide excellent models for studying molecular mechanisms of maize resistance to the fungus. MicroRNA-like RNAs (milRNAs) recently identified in A. flavus had been found to be correlated with aflatoxin production conditions, suggesting that the milRNAs might play a role in the regulation of aflatoxin production. In this research, small RNAs were isolated from kernels of maize (resistant Mp719 and susceptible Va35) …

River Bank Inducement Influence On A Shallow Groundwater Microbial Community And Its Effects On Aquifer Reactivity, Natalie June Gayner

Theses and Dissertations

Placing groundwater wells next to riverbanks to draw in surface water, known as riverbank inducement (RBI), is common and proposed as a promising and sustainable practice for municipal and public water production across the globe. However, these systems require further investigation to determine risks associated with river infiltration especially with rivers containing wastewater treatment plant (WWTP) effluent. Since microbes drive biogeochemical transformations in groundwater and largely affect water quality, it is important to understand how the microbial communities in drinking water wells are affected by river infiltration. This study investigated if, and to what extent, the microbial community in a …

Renalase As An Intracellular Metabolite Repair Enzyme, Matthew Robert Hoag

Theses and Dissertations

The human enzyme renalase was discovered in 2005 by nephrologist Gary Desir, who claimed the enzyme is secreted by the kidney into the blood where it was said to catabolize catecholamines in order to modulate blood pressure and heart rate. It has since been shown that the enzyme is expressed in all tissues and does not react with catecholamines. The research detailed in this dissertation led to the discovery that renalase oxidizes two highly toxic isomers of NAD(P)H to form innocuous NAD(P)+. We surmised that such an important cellular function would be pervasive in nature, and our lab was the …

Studies In Molecular Recognition: Non-Proteogenic Amino Acids For Antibiotic Studies And Chemosensors For Recognition And Reporting Of Metal-Ions, Sarah Anne Oehm

Theses and Dissertations

The field of molecular recognition focuses on the selective and reversible binding of small guest molecules to larger host molecules. This dissertation describes synthesis of small molecules as binding guests for enzymatic substrates as well as molecules as host chemosensors to detect and identify metal ions. Two approaches to new antibiotic drugs have been explored, and an array of sensors for the quantitation of aqueous metals is being commercialized.

As strains of deadly bacteria emerge with evolved resistance to known antibiotics, new drugs are needed with novel mechanisms of action. Natural product antibiotics containing enduracididine, a non-canonical amino acid derived …

An Introductory Study Of Solid Materials For Capture And Catalysis Of Waste Stream Chemicals, Steven Kyle Butler

Theses and Dissertations

Heterogeneous catalysts are key materials in research and industry. Herein we study two materials in different stages of development toward being applied as heterogeneous catalysts. First, MoO3SnO2 was synthesized and studied as a catalytic system similar to Sn-beta zeolites. While the Mo-based catalyst did not show similar activity to Sn-beta, it did show interesting reactivity in activating carbonyls and oxidizing organic substrates. Second, a method was developed for grafting amines onto carboxylic acid functionalized carbon nanotubes for CO2 capture. The method was successful for grafting monomer ethylamine groups onto CNT and can be further developed to allow for polymeric amine …

Impacts Of Sieving And Cultivation On Martian Regolith Simulant, Abdulgadir Ahmad Elnajdi

Theses and Dissertations

The effect of different size particle fractions of JSC-MARS1A on chemical and mineralogical data was examined in this study. The Powder X-ray Diffraction (PXRD) and Scanning Electron Microscopy (SEM) results showed no difference in the presence of elements or minerals of the different grain sizes of (<5mm, <1mm, <125μm, and <63μm), however, differences in abundance were noted. In addition, changes in chemical composition and mineralogy were not detected after the addition of Hoagland’s nutrient solution which had been applied prior to plant growth experiments nor after plant growth.

Interactions Of Viral And Cellular Helicases, Megan Josephine Corby

Theses and Dissertations

The innate immune system is a part of the first line of defense against virus infection. An important subset of the innate immune system consists of a group of intracellular pattern recognition receptors (PRRs) which recognize conserved features of bacteria and viruses and initiate an interferon response. The RIG-I like receptors (RLRs) are PRRs that bind to RNA viruses (such as hepatitis c virus) and signal through the adaptor mitochondrial anti-viral signaling protein (MAVS).

Hepatitis C virus (HCV) is a small enveloped RNA virus that belongs to the flaviviridae family of viruses. HCV infects hepatocytes and can cause a persistent …

Time-Resolved Structural Enzymology At X-Ray Free Electron Lasers, Tyler Norwood

Theses and Dissertations

Within the last decade, X-ray Free Electron Lasers (XFELs) have emerged across the world. These XFELs produce X-ray pulses with a duration on the order of femtoseconds, each of which contains 1012 photons. Before the XFEL, the brightest X-ray sources were 3rd generation synchrotrons. While these facilities are still very important for many experiments, XFELs allow for time-resolved experiments with femtosecond time resolution and mixing experiments that are not possible at the synchrotron. Enzymatic processes have promising prospects for medicine which use proteins as drug targets and enhance our understanding of these important biomolecules.

A number of procedures are involved …

The Heart Of The Madder: An Important Prehistoric Pigment And Its Botanical And Cultural Roots, Michelle Laberge

Theses and Dissertations

In recent years, an interest in natural botanical dye sources has prompted new research into the cultivation and processing of prehistoric dye plants. Advances in chemical analyses of ancient European textiles have provided more information about dye plants such as woad (Isatis tinctoria) weld (Reseda luteola) and madder (Rubia tinctorum), which were important sources of color in early textile production. Evidence of madder dye has been reported in the archaeological record of the European Bronze and Iron Ages in textiles preserved in the Hallstatt salt mines, Scandinavian bog sites and other elite European burials but the picture of madder usage …

Role Of The Two Adaptor Proteins In The Chp Chemosensory System Of Pseudomonas Aeruginosa, Swati Sharma

Theses and Dissertations

The Chp chemosensory system in Pseudomonas aeruginosa controls two outputs: twitching motility (surface-mediated movement via Type IV pili) and intracellular adenosine 3’, 5’-cyclic monophosphate (cAMP) levels (by modulating the activity of major adenylate cyclase CyaB). This study was done to investigate the roles of the two adaptor proteins, PilI and ChpC in connecting one methyl-accepting protein (MCP) to one histidine kinase. We assayed -galactosidase activity as an indicator of the relative levels of intracellular cAMP and measured twitching motility. We also studied the interaction of the adaptor proteins within the Chp chemosensory system. Our bacterial adenylate cyclase two-hybrid analysis showed …

New Direct Acting Anti-Virals Inhibiting Hepatitis C Virus Helicase And Insights Into How Atp Fuels Helicase Action, Mark Yerukhimovich

Theses and Dissertations

According to the World Health Organization, Hepatitis C Virus (HCV) has infected 130-150 million people worldwide. Approximately 700,000 of those die each year from chronic HCV related causes such as cirrhosis or cancer. Currently, there are numerous HCV drugs on the market; they target the protease, polymerase and NS5A proteins encoded by of HCV. These drugs are expensive and HCV can become resistant, thus there is constant need for new DAAs. The first part of this thesis examines the search for additional drugs that function by inhibiting the NS3 helicase, which have been challenging to develop.

Part of the reason …

The Effect Of Ammonia On The Germination And Outgrowth Of Bacillius Globigii, Joseph B. Kunicki

Theses and Dissertations

This research investigated the germination and outgrowth of Bacillus globigii in the presence of ammonia in laboratory scale experiments. Germination was measured by monitoring the release of dipicolinic acid, an organic compound present in bacterial spores, while outgrowth was measured using phase-bright microscopy and semi-automated counting procedures. The ammonia-N concentrations investigated generally did not cause statistically significant differences in the initial 1-hr germination rates or the average 3-hr outgrowth rates of Bacillus globigii spores in batch style experiments. The average 1-hr germination rates observed in the absence of ammonia-N was 0.0258 hr^-1 for the water and buffer controls and …

Contribution Of Bulky <&Alpha>,<&Beta>-Dehydroamino Acids To The Proteolytic Stability Andenhanced Folding Of <&Beta>-Hairpins And Progress Towards The Total Synthesis Of Yaku<'>Amide A, Ankur Jalan

Theses and Dissertations

This dissertation primarily covers the impact of bulky ,-dehydroamino acids on the proteolytic stability and enhanced folding of -hairpins. It partly describes the progress towards the total synthesis of yakuamide A, a potent anticancer peptide with an IC50 value of 14 ng/mL against leukemia cells. Proteins and peptides are a very attractive source of potential medicinal agents as they can target various protein“protein interactions that are implicated in several diseases and disorders. The global sales of peptide drugs in 2013 were estimated to be about $28 billion and are constantly rising at an appreciable rate. However, peptide drugs have a …

Processing Of 3′-Blocked Dna Double-Strand Breaks By Tyrosyl-Dna Phosphodiesterase 1, Artemis And Polynucleotide Kinase/ Phosphatase, Ajinkya S. Kawale

Theses and Dissertations

DNA double-strand breaks (DSBs) containing unligatable termini are potent cytotoxic lesions leading to growth arrest or cell death. The Artemis nuclease and tyrosyl-DNA phosphodiesterase (TDP1) are each capable of resolving protruding 3′-phosphoglycolate (PG) termini of DNA double-strand breaks (DSBs). Consequently, a knockout of Artemis and a knockout/knockdown of TDP1 rendered cells sensitive to the radiomimetic agent neocarzinostatin (NCS), which induces 3′-PG-terminated DSBs. Unexpectedly, however, a knockdown or knockout of TDP1 in Artemis-null cells did not confer any greater sensitivity than either deficiency alone, indicating a strict epistasis between TDP1 and Artemis. Moreover, a deficiency in Artemis, but not TDP1, resulted …

Cellular Inhibitor Of Apoptosis Protein2 – A Critical Regulator Of Neuroinflammation, Debolina Dipankar Biswas

Theses and Dissertations

Inhibitors of apoptosis (IAPs) modulate cell death and play critical role in signal transduction that promotes inflammation. Recently, Smac mimetics, which are IAP antagonists, have attracted attention as novel cancer therapeutics. Cellular Inhibitor of Apoptosis 2 (cIAP2), a member of IAP family, positively affects both NF-κB and MAPK activation in response to many inflammatory stimuli. We observed that the lack of cIAP2 ablates LPS-induced neuroinflammation. Also, cIAP2^-/- macrophages demonstrated diminished antigen presentation potential that could contribute to ablated immunity. In addition to these functions, we have previously reported that cIAP2 also regulates the activation of Interferon Regulatory Factor 1 …

Chronic Clozapine Treatment Impairs Functional Activation Of Metabotropic Glutamate Receptor 2 Via An Hdac2-Depedent Mechanism, Travis M. Cuddy

Theses and Dissertations

Schizophrenia is a chronic mental disorder affecting millions worldwide. It has no known cure. Current pharmaceutical treatments have shown efficacy in only one of the three symptom clusters of schizophrenia, providing little or no benefit in the other two. Furthermore, the current standard-of-care drugs, known as atypical antipsychotics, carry risks of severe side effects affecting multiple body systems. Most patients opt to discontinue drug therapy within two years of initiation due to lack of efficacy and/or preponderance of adverse effects. Previous findings have shown that chronic usage of atypical antipsychotics causes a 5-HT_2A-dependent upregulation of histone deacetylase 2 …

Impact Of Phosphoinositides On Regulation Of K-Atp By Atp And Hydrogen Sulfide, Tyler Hendon

Theses and Dissertations

Hydrogen sulfide (H2S) reduces ischemia reperfusion (IR) injury by stimulating adenosine triphosphate (ATP) sensitive potassium channels (KATP) [1-5]. Demonstrating H2S stimulation is unique to KATP, as other inwardly rectifying potassium (Kir) channels demonstrate inhibition or are unaffected [6]. We recently showed that H2S inhibits Kir2 and Kir3 by decreasing channel sensitivity to phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2 or PIP2) [6]. Here, we test the hypothesis that H2S regulation of Kir6.2, a pore-forming subunit of the KATP channel, is also dependent on PIP2. Using whole-cell patch-clamp we show that H2S increases the activity of Kir6.2 channels expressed in HEK-293 cells. To study the …

Zebrafish Model Of Mll-Rearranged Acute Myeloid Leukemia, Alex J. Belt

Theses and Dissertations

Acute myeloid leukemia (AML) is the second most common type of leukemia and accounts for 80% of adult acute leukemia cases and is characterized by the accumulation of poorly or undifferentiated myeloid blast cells. Standard treatment includes chemotherapy, which if unsuccessful, is followed by more rigorous chemotherapy as well as stem cell transplantation. Considering most patients are over the age of 45, these more rigorous therapies are not always possible, and as such, new therapies must be developed. Furthermore, AML patients harboring a chromosomal rearrangement involving Multiple Lineage Leukemia (MLL) that results in the expression of an MLL fusion protein …

Nicotinic Acetylcholine Receptor Dependent Effects Of Nicotine On Hek293t And Hbo Cells, James D. Larsen

Theses and Dissertations

T2R receptors are the classical bitter taste receptors which detect and transduce bitter taste in a subset of taste receptor cells (TRCs). The TRPM5-dependent T2Rs are G-protein coupled receptors (GPCRs) and are linked to G protein, gustducin to initiate an intracellular signaling cascade for the transduction of bitter tastants. Nicotine is bitter. However, at present the transduction mechanisms for the detection of nicotine in are poorly understood. Previous studies from our laboratory using TRPM5 knockout (KO) mice demonstrated that the T2R pathway is insufficient in explaining the taste perception of nicotine. TRPM5 KO mice elicited chorda tympani (CT) taste nerve …

The Interaction Between Ceramide-1-Phosphate And Group Iva Cytosolic Phospholipase A2 And Its Role In Wound Healing, Patrick Macknight

Theses and Dissertations

The sphingolipid, ceramide-1-phosphate (C1P), directly binds and activates Group IVA cytosolic phospholipase A₂ (cPLA₂a) to generate eicosanoids. Due to the role of eicosanoids in wound healing, we choose to use our novel genetic mouse model expressing cPLA₂a with an ablated C1P interaction site (KI) to examine the cPLA₂a/C1P interaction in wound healing. Wound closure rate was not affected, but wound maturation was dramatically enhanced by loss of the C1P/cPLA₂α interaction based on the following findings. Wounds in KI mice displayed: i) increased infiltration of dermal fibroblasts into the wound environment; ii …

Signaling Through Homomeric And Heteromeric Cannabinoid Cb1 Receptors, Guoqing Xiang

Theses and Dissertations

Cannabis (Marijuana) has multiple effects on the human body, such as analgesia, euphoria and memory impairment. Delta-9 tetrahydrocannabinol (D9-THC), the active ingredient in cannabis, binds to cannabinoid receptors, seven-transmembrane G protein-coupled receptors (GPCRs) that mediate a variety of physiological functions. GPCRs were believed to function only in homomeric forms, however, recent findings show that different GPCRs can also form heteromeric complexes that may expand their signaling properties. In this study, we focused on Cannabinoid CB1 receptor (CB1R) heteromers with the mu-opioid receptor (MOR) and the Dopamine type 2 receptor (D2R), respectively. We utilized a variety of techniques, such as the …

In Vitro Genetic Code Expansion And Selected Applications, Emil S. Iqbal

Theses and Dissertations

The ability of incorporation non-canonical amino acids (ncAAs) using translation offers researchers the ability of extend the functionality of proteins and peptides for many applications including synthetic biology, biophysical and structural studies, and discovery of novel ligands. Here we describe the three projects where the addition of ncAAs to in vitro translation systems creates useful chemical biology techniques. In the first, a fluorinated histidine derivative is used to create a novel affinity tag that allows for the selective purification of peptides from a complex mixture of proteins. In the second, the high promiscuity of an editing-deficient valine-tRNA synthetase (ValRS T222P) …

Decoding The Signaling Of The D2r-2ar Heteromer: Relevance To Schizophrenia, Miao Huang

Theses and Dissertations

Schizophrenia is a severe mental disorder affecting ~1% of world population. Two G protein coupled receptors (GPCRs): Gi-coupled dopamine D2 receptor (D₂R), and Gq-coupled serotonin 2A receptor (2AR), are targeted by the typical and atypical antipsychotic drugs to treat schizophrenia. These two receptors have been shown to co-localize in brain regions relevant to schizophrenia, including the ventral tegmental area (VTA), striatum, and prefrontal cortex (PFC). Studies in our lab characterized the integrated signaling of the D₂R-2AR heteromer and found that both the Gi activity of D₂R and the Gq activity of 2AR were potentiated …

Modulation Of Electron Transport By Metformin In Cardiac Protection: Role Of Complex I, Ahmed Abdul Hussein Mohsin

Theses and Dissertations

Modulation of mitochondrial complex I during reperfusion reduces cardiac injury. Complex I exists in two structural states: active (A) and deactive (D) with transition from A→D during ischemia. Reperfusion reactivates D→A with an increase in ROS production. Metformin preserves the D-Form. Our aim was to study the contribution of maintenance of deactivation of complex I during early reperfusion by metformin to protect against ischemia reperfusion injury. Our results showed that metformin decreased H9c2 cardiomyoblast apoptosis and total cell death following simulated ischemia for six hours followed by reoxygenation for twenty four hours compared to untreated cells. Reactive oxygen species (ROS) …

Rep-Dna Complexes And Their Role In Aav Dna Transactions, Vishaka Santosh

Theses and Dissertations

Adeno-associated Virus (AAV) Rep proteins are multifunctional proteins that carry out various DNA transactions required for the life cycle of AAV. The Rep proteins have been found to be important for genome replication, gene regulation, site-specific integration and play an essential role in genome packaging. There are two main groups of Rep proteins: large and small Reps; both groups are SF3 helicase family members. During DNA packaging, studies have shown that the small Rep proteins are critical to produce fully packed particles. Using stopped-flow kinetic analysis, we show a significant difference in helicase activity between the small and large Rep …