Life Sciences Commons^™

Towards The Total Synthesis Of Thioviridamide: Thiyl Radical Approach To The Beta-Thioenamide Linkage Formation, Jung-Hoon Kang

Theses and Dissertations

We developed an approach to the β-thioenamide linkage contained in the S-(2-aminovinyl)cysteine (avCys) residue of thioviridamide.1,2 Kinetic and thermodynamic control of radical additions of thiols to ynamides were studied for the formation of β-thioenamide linkage. Thiyl radicals are electrophilic and ynamides are electron-rich alkynes. This complementary polarity of the radical and acceptor increases the likelihood of a successful radical addition reaction. Because little is known about these types of compounds (β-thioenamides), we were unsure what kinds of yields and stereoselectivities (cis vs. trans) to expect. The adduct stability is another issue to consider. Fortunately, under typical radical addition conditions, the …

Comparison Of Two Training Programs On Acceleration Out Of The Break In American Football, Micah Adam Alba

Theses and Dissertations

Athletes of American football need the ability to stop, start, and reach top speed in an efficient manner. Football players on the defensive side of the ball require the skill of stopping a backward run and accelerating to a forward run. This action is termed the break. Football players receive year-round training in an effort to improve performance. Yet, many times, these athletes may not focus specifically on the muscular systems that are unique to the position they play. The law of specificity states that the more specific the training is for the action required, the more beneficial the outcome. …

Iron Acquisition In Rhodococcus Erythropolis Strain Igts8: Characterization Of A Mutant Strain That Over Produces Siderophore., Melanie Anne Pratt

Electronic Theses and Dissertations

Iron is an essential nutrient for most bacteria because enzymes like nitrate reductase and cytochromes use it as a cofactor. However, in most aerobic, neutral pH environments, iron is essentially insoluble and not easily available for bacteria to use. Many bacteria respond to this problem by releasing small organic compounds called siderophores that bind and effectively solubilize iron so that it can be transported into the cell for growth. The focus of this study was to learn more about the iron acquisition and especially the transport of iron by the soil bacterium Rhodococcus erythropolis. To fulfill this aim, mutant …

Elucidating The Role Of The Α7 Nicotinic Receptor In The Etiology Of Schizophrenia., Michelle Johnson Chandley

Electronic Theses and Dissertations

The α7 subunit of the nicotinic receptor, a ligand gated ion channel with an affinity for nicotine, has long been implicated in the pathophysiology of schizophrenia due to the extremely high rate of smoking within the patient population. However, the exact role of the receptor has never fully been determined. In the following studies, various functions the receptor may assume in disease state are evaluated. There is a strong relationship between the immune system and schizophrenia, with the α7 subunit possibly serving as the link between the two. One of the following studies looks at the possibility of the receptor …

Herpes Simplex Virus Glycoprotein D/Host Cell Surface Interaction Stimulates Chlamydia Trachomatis Persistence Via A Novel Pathway., Jennifer Vanover

Electronic Theses and Dissertations

When presented with certain unfavorable environmental conditions, C. trachomatis reticulate bodies (RBs) enter into a viable, yet noncultivable state called persistence. Two hallmarks of persistent chlamydiae are swollen, aberrantly shaped RBs, as viewed by transmission electron microscopy and a decrease in infectious progeny. Several models of chlamydial persistence have been described, including interferon-γ (IFN-γ), IFN-α, IFN-β, and tumor necrosis factor-α-exposure and nutrient deprivation. Previously, we established an in vitro co-infection model of two of the most common sexually transmitted pathogens in the United States, C. trachomatis and Herpes Simplex Virus-2 (HSV). Data from this tissue culture model indicate that: i) …

Urinary Excretion Of (1-3)-Beta-D-Glucans., Debra K. Head

Electronic Theses and Dissertations

(1→3)-β-D-Glucans are carbohydrate polymers that are present in the cell wall of various fungi and bacteria; they are pathogen associated molecular patterns that circulate during infection and modulate immunity. Our laboratory has previously established the pharmacokinetics of intravenously and orally administered glucans; the present studies investigated the renal excretion of (1→3)-β-D-glucans following intravenous and oral administration. Three fluorescently-labeled glucans were administered to adult male rats in the presence or absence of toxic challenge. Urine specimens were collected and analyzed by fluorescence spectroscopy, size-exclusion chromatography and GPC/MALLS. 71 ± 3% of fluorescence remained in the >5K MWCO fraction; this fraction showed …

Ecology Of The Evening Bat (Nycticeius Humeralis) At The Northern Edge Of The Range, Olivia Maya Munzer

Master's Theses and Doctoral Dissertations

Only a single colony of evening bats (Nycticeius humeralis) is known to occur in Michigan, and it is the northernmost colony on the North American continent. In mid-May, only female evening bats migrate to Michigan to raise their pups, and in late August, evening bats migrate to southern portions of their range, where they are ubiquitous. I studied the roosting and dietary ecology of the evening bat in southeastern Michigan. Evening bats roosted in cavities, crevices, and under exfoliating bark of older trees located in a bottomland forest, interlaced with waterways and surrounded by agricultural fields. These habitats …

Effects Of Metal Protoporphyrins On Burn Wound Conversion, Katie Braun

Theses and Dissertations

A murine model was utilized to test the influence of heavy metal protoporphyrins on burn conversion, heme oxygenase – 1 (HO-1) expression, and inflammation. Heavy metal protoporphyrins, such as cobalt protoporphyrin (Co PP) and tin protoporphyrin (Sn PP), were used to influence the heme oxygenase activity. The effects of these heavy metal protoporphyrins on burn wound conversion were examined using a burn comb model in rats. In addition to assessing the extent of conversion, HO-1 expression and parameters of inflammation were also examined in the area of injury (interspace region) subject to conversion. These studies demonstrate proof in principal that …

Effects Of Light Exposure On The Release Of Oxygen From Hemoglobin In A Red Blood Cell Suspension, Tanikka Toler

Theses and Dissertations

The main function of the cardiovascular system is to deliver a sufficient quantity of oxygenated blood to the tissues, cells, and organs of the body in order to provide the cells with essential nutrients for metabolism and for the removal of waste products. All cells require and utilize oxygen. Oxygen is transported to various cells and tissues via red blood cells flowing through the microcirculation of an organism. Measurement of oxygen transport in the microcirculation has shown that about ten times more oxygen appears to leave the blood of arterioles than can be accounted for by diffusion. One possibility to …

Does Shape Predict Performance? An Analysis Of Morphology And Swimming Performance In Great Basin Fishes, John R. Aedo

Theses and Dissertations

Swimming performance strongly influences fitness in aquatic organisms and is closely tied to external body morphology. Although this connection has been closely examined at the individual and species level, few studies have focused on this relationship as it pertains to functional group assemblages. Using functional groups based on similarities in habitat use and morphology, I tested the hypothesis that swimming performance can be reliably predicted by functional group composition. I measured swimming performance as burst speed using a simulated predator attack and as prolonged speed using a step-endurance test in a laboratory flume. I measured morphology using geometric morphometric techniques. …

Molecular Mechanisms Involved In Oligodendrocyte Development, Rochelle Coelho

Theses and Dissertations

Multiple sclerosis (MS) is a chronic disease of the central nervous system (CNS) characterized by demyelination and loss of oligodendrocytes (OLGs), the CNS myelin-producing cells. Thus, understanding the mechanisms that control OLG development can provide valuable knowledge regarding remyelination therapies for MS. This disease is thought to result from an autoimmune attack towards myelin. FTY720, an immunomodulator under evaluation for MS treatment is a sphingosine-1-phosphate (S1P) analog. We found before that S1P plays a crucial role in the NT-3-mediated survival of OLGs, an observation that led us to investigate whether FTY720 could have any effect on these cells. Our studies …

A Correlational Study: The Relationship Between Physical Activity Levels, Physical Self-Worth, And Global Self-Worth In High School Physical Education Students, Ashley Danelle Eyre

Theses and Dissertations

The purpose of this study was to determine the relationship between physical activity levels, physical self-worth, and its sub-domains; (a) skill, (b) body attractiveness, (c) fitness and conditioning, and (d) strength, and overall global self-worth in high school students. One-Hundred and sixty-seven students (male = 66;female = 101) from the western United States, ages 13-18, participated in this study. Each participant completed a minimum of four days of physical activity (PA) data collection and completed the self-worth questionnaire. Pedometers were used to collect PA levels, calculating mean step counts, and the Children and Youth Physical Self-Perception Profile (CY-PSPP) was used …

A Population Genetic Study Of Middle Eastern Populations Using Dys 458 Microvariants And Cohen Modal Haplotypes, Enass Nabeel Tinah

Theses and Dissertations

A comprehensive population study in the Middle East was conducted using different genetic markers in order to establish a wider genetic profile of the Middle Eastern populations. The main goal of this study was to analyze DNA from samples collected from different locations, and produce genetic motifs and patterns that could be used to identify and distinguish the target populations. This information will allow us to analyze the ancestry of these populations, their interactions through time and space, and the effects these interactions have on the populations' structure. We have collected around 1300 individual samples from different populations in the …

Co-Administration Of Sildenafil Potentiates Doxorubicin-Induced Apoptosis In Prostate Cancer: The Role Of Nf-Kappab, Sarah Hassanieh

Theses and Dissertations

Our recent studies have shown that that erectile dysfunction (ED) drugs including Sildenafil (Viagra), Vardenafil (Levitra) and Tadalafil (Cialis) enhance killing of several types of cancer cells by anticancer drug, Doxorubicin (DOX). We observed increased cell death by apoptosis in response to the combined treatment with ED drugs and DOX. However, the mechanism of such enhancement of cell death by combined treatment of ED drugs and DOX is not fully understood. Nuclear factor-κB (NF-κB) is an oxidant-sensitive transcription factor that plays a critical role in the immediate-early activation of a multitude of genes that have been documented to play critical …

Regulation Of Mdm2 Mediated Nfκb2 Pathway In Human Lung Cancer, Lathika Mohanraj

Theses and Dissertations

Overexpression of oncoprotein MDM2 and mutations of tumor suppressor p53 are frequently observed in human cancers. The NFκB pathway is one of the deregulated pathways in oncogenesis. The overall goal of the project was to study the regulation of NFκB pathway by MDM2 in lung cancer. Our first effort was to determine the frequency of MDM2 overexpression in human lung tumor samples and to identify co-occurring abnormal gene expression by studying the levels of MDM2 and members of NFκB pathway with respect to p53 status. Higher than normal levels of MDM2 were found in approximately 30% of the cancer samples …

The Effects Of Excess Corticosterone On Lkb1 And Ampk Signaling In Skeletal Muscle Of Rats, Gary N. Nakken

Theses and Dissertations

Cushing's syndrome and glucocorticoid therapy lead to central obesity, insulin resistance, and symptoms of altered energy regulation similar to those observed in the metabolic syndrome. We hypothesized that excess glucocorticoids alter energy sensing/signaling in skeletal muscle through mediation of the LKB1/AMPK signaling pathway. To test this hypothesis, three 100 mg pellets of corticosterone were implanted subcutaneously in each of nine rats for two weeks. Responses were compared with sham operated controls fed ad libitum or food restricted to produce the body weights similar to the treatment group rats. After the treatment period, animals were anesthetized and the right gastrocnemius-plantaris and …

Mechanisms For Methylmercury Cell-To-Bath Transport By The Basolateral Membrane Of The Rabbit Proximal Tubule, Carol Ann Hoban

Biology Dissertations

The bath-to-cell transport, cytosolic concentration, and tubular content of methylmercury (Me203Hg+) and the sulfhydryl-amino acids and sulfhydryl-amino acid derivatives conjugated to Me203Hg+ were studied in the non-perfused S2 segments of the proximal tubule of the rabbit kidney. Active transport of Me203Hg+ was established by a temperature dependent (greater than 100% reduction in bath-to-cell transport, 99% decrease in cytosolic concentration, 63% decline in the tubular contents at 12°C when compared to 37°C). Conjugates of Me203Hg+ showed mixed results, with L-cysteine and L-taurine demonstrating the most significant increase in uptake. Transport of Me203Hg+-L-cysteine was also temperature dependent with a 77% reduction in …

Does Light Control Algal Abundance In Large River Systems?, Amy Macdonald

Theses and Dissertations

A limited amount of research has been done to investigate the factors influencing algal abundance in large river systems. This study examines light as the primary factor that controls algal abundance in the Upper Mississippi, Missouri and Ohio Rivers. Data were collected for 2004 in conjunction with the Environmental Monitoring Assessment Program- Great River Ecosystems EMAP-GRE project using EPA approved methods. Chlorophyll a concentrations were 34.6 µg•L-1 in the Upper Mississippi, 19.8 µg•L-1 in Missouri River and 9 µg•L-1 in the Ohio River for 2004. Chlorophyll a concentrations were significantly different among the three rivers (p<0.0001) but not between years. Inter-river variation could be loosely correlated with light availability: mean Average Irradiance Dosages, which consider factors that affect light climate (depth, transparency, velocity, surface irradiance), by river corresponded with mean chlorophyll a levels by river. Intra-river variation seemed to be due to both the influence of light and nutrients.

Crosstalk Between Mdm2 And Akt Signaling Pathway In Oncogenesis., Mahesh Ramamoorthy

Theses and Dissertations

MDM2, the human homologue of the Mouse Double Minute 2 gene product, has been shown to be over-expressed in many cancers and to induce tumorigenesis. The role of MDM2 in oncogenesis was thought to be p53 dependent. However recent years have shown MDM2 to be a key player in a complex network of interactions that affect cell cycle, apoptosis, and tumorigenesis in a p53 independent manner. Here we report a novel p53 independent role for the multidimensional protein MDM2; its ability to induce phosphorylation of Akt at serine 473 residue. Transient and stable over-expression of MDM2 in cultured cell lines …

Using Pedometers As A Valid Method Of Determining Physical Activity Intensity Level, Alan M. Groves

Theses and Dissertations

As researchers explore the benefits of using pedometers to assess physical activity they are discovering that intensity of physical activity may be estimated from steps per minute (SPM). The purpose of this study was to determine the SPM and kilocalories (kcals) expended associated with moderate physical activity in middle school students (12 - 14 years old). Methods: Ninety-three (49 boys, 44 girls) middle school youth between the ages of 12 and 14, walked on a treadmill at four different speeds (4.0, 4.8, 5.64, and 6.4 km/h) for three minutes at each speed. Each participant wore a pedometer in order to …

Evaluation Of Methods For Establishing Vegetation In Created Wetland Mitigation Sites In Eastern Nebraska, Andrew A. Miller

Student Work

Seventeen wetland mitigation sites in eastern Nebraska were evaluated, by vegetative zone, to assess the relative success of active and passive wetland vegetation establishment techniques. For sites with available records of species introduced, 46% of the seeded species and 31% of the transplanted species were successfully established suggesting that the intentional introduction of species (i.e. active methods) provides some degree of success in wetland creation. No significant differences were observed within or among active or passive methods for Species Richness (S), Shannon-Wiener diversity (H′), or the Floristic Quality Index (FQI) (Kruskall-Wallis test P < 0.05). However, while not statistically significant, general trends showed that, in the temporarily flooded zones, seeding resulted in both the highest overall plant diversity and highest FQI (S = 20.2, H′ = 1.74, FQI = 8.99) and, among species with cover values > 0.5%, the lowest percent non-native species (6.2%). …

The Development Of A Dual-Tag Affinity Purification System And Its Application To Elucidate The Interacting Protein Network Surrounding The Human Telomere Binding Proteins Trf1, Trf2, And Pot1, Richard John Giannone

Doctoral Dissertations

Protein-protein interactions (PPI) play a vital role in almost every cellular process. Although many methodologies exist to probe PPIs, one of the most successful and widely employed is tandem affinity purification coupled with liquid chromatography and tandem mass spectrometry (LC-MS/MS). Although best demonstrated in yeast, TAP has encountered significant hurdles in its application to mammalian systems, especially the observed low yield of bait protein and its interacting partners after two consecutive purifications.

To address these issues, a novel dual-tag affinity purification (DAP) system was developed that not only enhances bait protein recovery, but also allows for rapid evaluation of dual-tag …

Cis-Acting Determinants Of Coronavirus Genome Translation And Replication, Kortney Michele Gustin

Doctoral Dissertations

Coronaviruses are a family of positive-sense, single-stranded, 5’-capped and 3’- polyadenylated RNA viruses that replicate entirely in the cell cytoplasm. Replication of the viral genome requires translation to produce proteins used for RNA synthesis and virion assembly. The 5’- and 3’- untranslated regions of the coronavirus genome have been found to contain cis-acting elements that are required for replication of the genome and a defective interfering RNA. Presumably, both viral and cellular proteins interact with these elements and serve as trans-acting factors in genome translation and replication. Of interest is the functional significance of a 5’-proximal cis-acting 397-nucleotide …

Comparative Functional Genomics Of The Sabath Family Of Methyltransferases In Plants, Nan Zhao

Doctoral Dissertations

Known members of the plant SABATH family of methyltransferases (MTs) have important biological functions by methylating hormones, signaling molecules and other metabolites. This dissertation aims to systematically investigate the biochemical and biological functions and evolution of SABATH genes in plants. The genomes of rice and poplar have been fully sequenced, which provides unprecedented opportunities for cross-species comparison of the SABATH family. Using a comparative genomic approach, 41 and 33 SABATH genes were identified in rice and poplar, respectively. The expression of these genes in different tissue was analyzed using RT-PCR approach and some genes highly expressed in multiple tissues were …

Plant Improvement For Insect Resistance: Testing Of The Candidate Organism Beauveria Bassiana, Transgenic Tobacco Expressing Protease Inhibitors, And Rapid Screen Of Insect Resistance Genes In An Agroinfiltration Transient Expression System, Brian M. Leckie

Doctoral Dissertations

This study focused on three aspects of plant improvement for insect resistance including: testing of candidate organisms for their production of insecticidal proteins, testing of transgenic plants expressing insect resistance genes, and testing novel systems for the evaluation of insect resistance genes. In the initial part of this study, the candidate fungus Beauveria bassiana was tested for its production of insecticidal proteins through a series of insect bioassays containing fungal protein extracts. These extracts were shown to be orally toxic to Plutella xylostella (diamondback moth) and Spodoptera frugiperda (fall armyworm). Assays involving protease treatments significantly decreased mortality indicating the presence …

Evaluation Of Statistical Correlation And Validation Methods For Construction Of Gene Co-Expression Networks, Suman Duvvuru

Doctoral Dissertations

High-throughput technologies such as microarrays have led to the rapid accumulation of large scale genomic data providing opportunities to systematically infer gene function and co-expression networks. Typical steps of co-expression network analysis using microarray data consist of estimation of pair-wise gene co-expression using some similarity measure, construction of co-expression networks, identification of clusters of co-expressed genes and post-cluster analyses such as cluster validation. This dissertation is primarily concerned with development and evaluation of approaches for the first and the last steps – estimation of gene co-expression matrices and validation of network clusters. Since clustering methods are not a focus, only …

Plant Transcriptional Responses To Explosives As Revealed By Arabidopsis Thaliana Microarrays And Its Application In Phytoremediation And Phytosensing, Murali Malavalli Keerthi Narayana Raghavendra Rao

Doctoral Dissertations

This research focused on understanding genetic responses of plants to explosives, which is necessary to produce plants to detect and clean soil and water contaminated with toxic explosive compounds. The first study used microarray technology to reveal transcriptional changes in the model plant Arabidopsis thaliana exposed to the explosive compounds RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine; Royal Demolition Explosive or Research Department Explosive) and TNT (2,4,6-trinitrotoluene). This study yielded a list of genes up- and downregulated by explosive compounds, which can be potentially used for phytoremediation (remediation using plants) or phytosensing (detection using plants) of explosive compounds. The second study presented biotechnology tools to …

Gene Expression Profiles As Molecular Indicators Of Dissolved Oxygen Stress In Grass Shrimp Palaemonetes Pugio Holthuis 1949, Tiandao Li

Dissertations

Occurrence and severity of hypoxia is increasing in coastal and estuarine environments, and recovery of impacted habitats and living resources is slow. Detection of early biological effects of hypoxia is needed for timely remedial action to be taken. The overall objectives of this research was to develop molecular indicators of dissolved oxygen stress to assess the biological impact of hypoxia in coastal estuaries and validate their use through a combination of laboratory and field studies. To achieve these goals, grass shrimp, Palaemonetes pugio, oxygen-sensitive and hypoxia-tolerant species abundant in estuarine systems, were exposed to hypoxia under controlled laboratory conditions, and …

Yellow Head Virus: Transmission And Genome Analyses, Hongwei Ma

Dissertations

Yellow head virus (YHV) is an important pathogen to shrimp aquaculture. Among 13 species of naturally YHV-negative crustaceans in the Mississippi coastal area, the daggerblade grass shrimp, Palaemonetes pugio, and the blue crab, Callinectes sapidus, were tested for potential reservoir and carrier hosts of YHV using PCR and real time PCR. The YHV replicated in the daggerblade grass shrimp, and was still detectable on 36 d post-inoculation, causing 8% mortality after injection. However, YHV did not replicate in the blue crab. These data suggest that the daggerblade grass shrimp could act as a reservoir host for YHV. Storage conditions of …

Biochemical Characterization Of Two Yeast Paralogous Proteins Mth1 And Std1, Satish Pasula

Dissertations

Glucose is the most abundant monosaccharide and preferred carbon and energy source for most cells. Many organisms have evolved sophisticated means to sense glucose and respond to it appropriately. The budding yeast, Saccharomyces cerevisiae senses glucose through two transmembrane proteins, Snf3 and Rgt2. In the presence of extracellular glucose Snf3 and Rgt2 generate an intracellular signal that leads to the degradation of Mthl and Stdl, thereby inducing the expression of hexose transporter genes (EXT) by inhibiting the function of Rgtl, a transcriptional repressor of HXT genes. Mthl and Stdl are degraded via the Yckl/2 Kinase-SCFGrrl-26S proteasome pathway triggered by the …