Browsing University Honors Program by Title
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Catanach, Therese A. (August 29, 2007)[more][less]
Abstract: Based on museum-held and field-collected specimens new data are presented regarding the distribution, adult phenology and first-instar larva of the uncommon green lacewing Abachrysa eureka. It was found that this species is broadly distributed across the southeastern United States, from Texas to the east coast south to Florida and north to South Carolina. There are multiple short duration emergence periods which vary with latitude. This species appears to be a typical chrysopid in various biological aspects, such as the occurrence of a stalked egg and placement of debris on the backs of larva. URI: http://handle.tamu.edu/1969.1/5709 Files in this item: 1
CatanachTAthesis26iv2007.pdf (336.2Kb) -
Kolb, Frances Bailey (August 3, 2007)[more][less]
Abstract: This paper examines the influence of colonial policy and intercultural relations on the development of Acadian settlement in Louisiana between 1765 and 1785, spanning a portion of both French and Spanish colonial periods. Research has included an array of secondary sources, books, articles and maps, as well as a variety of primary sources, including published collections and archival material. Analysis of sources reveals two stages of Acadian settlement: the determination of physical location of settlements, and the characteristics, such as economic, demographic, and social, pertaining to the settlements. Political and social forces within colonial Louisiana affected the two stages of Acadian settlement differently. Colonial settlement and defense policies and Acadian culture influenced the location of settlements most strongly, while Acadian relations with other groups in Louisiana shaped the characteristics that the settlements developed during the 1770s. Acadian settlement indicates the imperial policies of France and Spain and the effect of these policies on the colonial population of Louisiana. URI: http://handle.tamu.edu/1969.1/5700 Files in this item: 1
Kolb_Frances_Fellows.pdf (957.5Kb) -
Bosshard, John (August 16, 2006)[more][less]
Abstract: Microscale devices capable of manipulating fluids have potential to give rise to a paradigm shift in the fields of biology and medicine. The purpose of this research is to assess the feasibility of applying single echo acquisition (SEA) magnetic resonance imaging (MRI) to microscale fluid flow quantification. This is important because development and improvement of microfluidic devices requires the ability to accurately and non-invasively measure microscale flow. Lab-on-a-chip aims to integrate an array of chemical laboratory tools onto a single chip, utilizing microfluidic flow for mass transport. Use of microfluidics results in improved speed and efficiency and allows operations that harness physical properties unique to the microscale. Current microscale flow visualization methods rely on fluorescence, requiring optically non-opaque fluids and device boundaries. Furthermore, these methods require insertion of labeled chemicals or seed particles into the flow, which may interfere with processes under observation. MRI has an established history of non-invasively quantifying flow through opaque boundaries but is limited by its slow image acquisition rate. SEA employs a 64-channel array coil to acquire a full image with each echo, significantly improving temporal resolution. Methods involve assessing the performance of SEA flow velocimetry on a scale of several millimeters by utilizing time-of-flight techniques. By taking a series of 5 ms snapshots, quantitative velocity information is obtained for laminar, transitional, and turbulent flow with Reynolds numbers ranging from 100 to 1200. Findings show that the turbulent eddies are visible and velocity information can be extracted from images, which means that SEA can accurately asses flow at the millimeter scale. In addition, SEA allows visualization of turbulent flow not accessible to standard MRI velocimetry techniques. It is concluded that SEA could be adapted as new tool for non-invasive quantification of optically inaccessible flow. Implications of this are that through integrated radio frequency microcoils, SEA MRI could be adapted as a new tool to study microfluidic flow resulting in improved microfluidic devices. URI: http://handle.tamu.edu/1969.1/3707 Files in this item: 1
Bosshard Thesis Formatting-Revised.pdf (2.352Mb) -
Holcomb IV, James R. (July 14, 2007)[more][less]
Abstract: Lacking sufficient funds to build and maintain a sizeable navy, the young United States was forced to employ privateers as a “stop-gap navy” in its struggles against stronger sea powers during the War for Independence, the Quasi War, and the War of 1812. Many American leaders opposed privateering on moral grounds, but felt compelled to employ it. Merchants and seamen were generally more supportive, wither because their usual employment, fishing and peaceful commerce, was denied them when enemies hovered outside American ports and began seizing American ships, or because privateering offered the prospect of quick and large profits. Sailors preferred service in privateers to enlisting in the navy because discipline tended to be less rigorous in privateers than in warships, privateers appeared safer since their captains generally tried to avoid combat with enemy men of war, and privateers offered the prospect of more prize money from the sale of captured ships. Officers in the Continental and United States Navy usually opposed privateering because privateers competed with them for recruits and for naval stores to fit their ships out for sea. Though controversial, it cannot be denied that privateering proved effective. The attacks launched by the private vessels on British and French commerce forced those governments to assign naval forces to protect their shipping. At home, privateering brought a level of prosperity to several American seaports that those communities had not experienced before. Despite its development of a regular navy during the nation’s first half century of independence, the United States continued to employ privateering as an integral part of its defense policy, attitudes toward the practice remained the same, merchants eagerly invested in privateering expeditions, and sailors viewed it as an attractive alternative to service in the regular Navy. URI: http://handle.tamu.edu/1969.1/5688 Files in this item: 1
Thesisrealfinal.pdf (62.82Kb) -
Muff, Rebecca A. (August 30, 2008)[more][less]
Abstract: Russia’s women have had a difficult time finding a voice in literature until as recently as the 1980s. With this new voice, many women writers have countered the widespread gender assumptions inherent in patriarchal Russian culture. This essay explores how four contemporary Russian women authors— Ludmilla Petrushevskaya, Nina Sadur, Tatyana Tolstaya, and Ludmila Ulitskaya—challenge binary gender stereotypes, particularly those concerning women. Each author has uniquely rejected a prescribed definition of ‘woman’ in her prose, and together the four authors form a literary rebellion against stereotypical notions of femininity. URI: http://handle.tamu.edu/1969.1/85752 Files in this item: 1
THESIS.pdf (604.1Kb) -
Cope, Nora (May 22, 2008)[more][less]
Abstract: My research explores the idea that the women of America’s past used cookbooks as life manuals and not just as collections of recipes. This project involves American gender roles and will be an important contribution to our women’s studies deficient academic community. I chose two different eras that have contrasting roles for women: World War II and the subsequent period of suburban growth. Next, I did a broad survey of as many cookbooks as I could that were published between 1942 and 1960, nationally distributed, and not regionally or ethnically focused. From this survey, I chose three books from each era that best represented these common characteristics to do a close reading of each text not as literature, but as an artifact of material culture. URI: http://handle.tamu.edu/1969.1/6914 Files in this item: 1
Cope_Thesis.pdf (603.4Kb) -
Davis, Nancy Diana (July 14, 2007)[more][less]
Abstract: The global marketplace has experienced an influx of messages surrounding the issues of corporate social responsibility and the effect of the economy on social values. Much of this debate is centered on appeals to business, government, and social organizations to actively pressure structures of commerce to maintain, if not improve, the quality of life for the public. As the world’s largest corporation, Wal-Mart Stores, Inc. has come under heavy attack from many groups which hope to change the company’s policies in order to better serve the greater community. The rhetorical discourse between these groups has cultivated an ongoing conversation composed of complex and strategic maneuvers, many of which are designed to either damage or boost Wal-Mart’s public reputation. The purpose of this study is to explore the reputation management strategies and themes present in the ongoing discussion between Wal-Mart Stores, Inc. and their counter points, specifically within the issues of labor relations and healthcare. This study was conducted in order to identify reputation management strategies employed by Wal-Mart Stores, Inc. and their rhetorical counterpoints. In addition to an extensive review of corporate communication theory literature, the paper demonstrates the pertinence of Wal-Mart Stores, Inc. as a case study. Several themes have emerged throughout the rhetorical activities of Wal-Mart Stores, Inc. which I argue will not pacify the relentless devotion of their foes, but rather spur on more rhetorical action. The paper concludes, then, that reputation management must be a continuous process for corporations. In order to withstand the turbulence of negative events, company’s such as Wal-Mart must bolster their images and trustworthiness in an ongoing campaign as opposed to sporadic issue management. Furthermore, the rhetorical discourse which occurs between the corporate world and its respective foes and surveillance groups requires the participation of all sectors of society to create constructive and progressive solutions. Unless all stakeholders are actively engaged in the problem solving process, the system will continue to disenfranchise various groups of society, further perpetuating a rhetorical cycle that neglects comprehensive, positive, systematic change. URI: http://handle.tamu.edu/1969.1/5687 Files in this item: 1
Microsoft Word - TEMPLATE.pdf (566.4Kb) -
McKay, Joshua L. (August 16, 2006)[more][less]
Abstract: This is the first step in a series of studies to test the feasibility of using Raman Spectroscopy (RS) to non-invasively detect physiologically relevant blood alcohol concentrations. Blood tests, urine tests, and the breathalyzer are currently the most commonly used techniques to measure blood alcohol content. Blood tests are invasive and require wet labs. Although urine tests are non-invasive, they also require wet labs. The breathalyzer is non-invasive and does not require a lab, but its accuracy has come into question. This method measures alcohol content in the alveolar air, which is not always a reliable predictor of alcohol content in the blood. A Raman-based technique could alleviate these problems and eventually replace or complement the breathalyzer. To explore this option, samples of ethanol-in-water from 0-1.0% (wt/vol) were prepared, and a time study was performed to test both the ability of RS to detect alcohol in relatively short amounts of time and to find an optimum scanning time. The spectra were used to create a partial least squares (PLS) model, which uses differences in the spectra to construct a model to describe the relationship between certain peaks and alcohol concentration. The model was used to predict the concentration of several known samples. The accuracy of the model’s prediction was compared for each stage of the time study. This study then focused on measuring ethanol concentrations in plasma, a much more complicated media than water. Again, a model was constructed, used to predict alcohol concentrations, and tested for accuracy. This study showed that Raman spectroscopy has the ability to detect alcohol in the physiological range in rather complex environments and in limited time windows, but repeatability is the main question. Spectra have a tendency to be inconsistent at such low alcohol concentrations, which results in a weak model and less accurate predictions. Description: Undergraduate Research Fellows Thesis URI: http://handle.tamu.edu/1969.1/3708 Files in this item: 1
Fellows Thesis.pdf (240.3Kb) -
Patel, Bhavini Narendrakumar (March 20, 2008)[more][less]
Abstract: Salmonella typhimurium is a bacterium that causes many food-borne illnesses such as gastrointestinal infections, diarrhea, and abdominal cramps. It affects 700,000 to 3.8 million people each year. The SseB protein, a part of the Salmonella Pathogenicity Island II (SPI2), plays a critical role in the pathogenesis of gastrointestinal infections. It is part of the Type III Secretion System (TTSS) that is involved in translocating proteins from the bacteria to the host gastro intestinal-epithelial cells. The aim of the research project is to clone, purify the SseB protein from Salmonella typhimurium and obtain a diffracting-quality crystal that will give high resolution data so that the structure of the protein can be determined using x-ray diffraction patterns. The SseB gene was amplified and cloned into pET30b vector and transformed into E. coli novablue cells. The SseB protein is then expressed into E. coli BL21 cells and purified using various chromatographic methods. Purified protein was used for crystallization and diffracting quality crystals were obtained using grid screening method. SseB protein crystallized in P-orthorhombic space group (P 21 21 21) and diffracted to 3.8Å. Further optimization is underway to get a good diffracting quality crystal. It is important to determine the crystal structure of SseB since this will reveal its role in the interaction with other translocation complex such as (SseC and SseD). Based on the structural information, potential drug targets can be designed for translocon complex, which can further prevent diseases caused by the bacterium Salmonella and other closely related bacteria. URI: http://hdl.handle.net/1969.1/6431 Files in this item: 1
Thesis Research Fellows Bhavini.pdf (2.019Mb) -
Hudson, Kara (July 23, 2007)[more][less]
Abstract: When a person suffers a spinal cord injury, peripheral damage often accompanies it, such as damage to the legs, for instance. The pain (nociceptive) signals from this peripheral injury are being sent to the damaged spinal cord, but the patient might not “feel” any pain because the ascending pathways are damaged by the spinal injury. Even though the affective component of pain is not present, the stimulation from peripheral injury could be damaging to locomotor recovery. This has been studied using a spinal contusion surgery on rats to simulate spinal cord injury, and uncontrollable shock to act as pain signals from peripheral injury. Although it is known that the brain is necessary for this destructive effect to occur, it is not known whether the brain initiates the effect, or if the signal must travel through the injury to induce the effect, making the spinal cord the primary initiator. This was examined by comparing the recovery of groups given shock above, versus below, the spinal cord injury. To minimize pain in shocked animals, all subjects received an analgesic dose of morphine. Prior work has shown that this treatment blocks behavioral signs of pain, but does not block the adverse consequences of stimulation on recovery. I found stimulation below, but not above, the site of a spinal contusion injury in rats impaired recovery. This supports that nociceptive signals only impair recovery if they engage spinal neurons below (caudal to) the site of injury. URI: http://handle.tamu.edu/1969.1/5695 Files in this item: 1
Kara Hudson Fellows Thesis 1.doc (110.0Kb) -
Hardin, Elizabeth Ashley (August 16, 2006)[more][less]
Abstract: Stressful life events have been linked to the onset, susceptibility, and even progression of neurodegenerative diseases such as multiple sclerosis (MS). Theiler’s murine encephalomyelitis virus (TMEV) infection, a well-characterized animal model of MS, is used in our laboratory to investigate the interaction between social stressors and disease development. Social disruption (SDR), a model of social stress used in our laboratory, appears to worsen Theiler’s virus infection through excessive inflammation. Prior findings from our laboratory indicate that pro-inflammatory cytokine IL-6 is partially mediating the negative effects of SDR in the development of Theiler’s virus infection. In order to examine the role of other pro-inflammatory cytokines, our objective was to develop techniques to block the cytokines TNF-α and IL-1β. Prior studies have indicated stress-induced release of these cytokines (TNF-α and IL-1β) may mediate the adverse effects of disease development in subsequent immune challenges. Balb/cJ mice were implanted with a permanent indwelling cannula in the left lateral ventricle of the brain and allowed to recover for one week prior to manipulations. Once the animals recovered from cannulation surgery, neutralizing antibody to TNF-α or IL-1β was administered during the period of SDR. Antibody-SDR treatments continued for one week. Mice were sacrificed the morning following last day of SDR. Brains and sera were collected to measure TNF-α or IL-1β levels. Spleens were harvested to examine the development of glucocorticoid resistance (GCR), a hallmark of SDR, in the TNF-α study only. The ELISA assay was not sensitive enough to the tissue levels of TNF-α, therefore successful antagonism was undetectable. In contrast, IL-1β was elevated during SDR; however, it appears that the antibody was only partially effective at the dose administered. The GCR assay indicated that resistance occurred in antibody treated and control mice in the TNF-α study, signifying that antibody treatment does not interfere with the development of normal social stress effects. Future studies are necessary to identify an effective blocking dose for the neutralizing antibody to IL-1β. In addition, we also need to develop alternative assays, such as RT-PCR or an RNase protection assay, that are sensitive to the levels of TNF-α associated with SDR. URI: http://handle.tamu.edu/1969.1/3719 Files in this item: 1
Ashley no-add GOOD VERSION.pdf (213.5Kb) -
Schiller, Aschley (July 18, 2008)[more][less]
Abstract: This study discusses the impact of photo alteration on journalistic credibility in relation to the effects of the new capabilities of digital technology. The thesis examines the early history of photo manipulation, in both digital and analog formats, and summarizes debates surrounding specific digitally altered images and the public’s and governing bodies’ responses to these alterations. Finally, digital photography’s position as a new medium or an extension of existing photographic means is considered. The research analyzes altered photos’ placements in media sources and uses the opinions of artists and theorists sourced from editorials, essays and texts to develop an understanding of the current uses of digital photographs, and to speculate about where the trend towards digital photography may lead. URI: http://handle.tamu.edu/1969.1/85719 Files in this item: 1
Photo Thesis Rasior.pdf (1.135Mb) -
Avila, Teresia Coleman (December 13, 2006)[more][less]
Abstract: This research was meant to discover whether, amid accusations they have become the super branch, the judiciary envisioned by the Founders is mirrored today. Reviewing constitutional origins led to the discovery that the Founders acknowledged federalism (divided government) and popular sovereignty as fundamental principles, the judiciary was one of three branches established to protect these principles, and Founders insisted on a written constitution. Federalists and anti-Federalists differed widely on how to implement these principles but all held them to be foundational. For over two centuries Americans have debated the proper interpretation of our compact. Questions persist regarding whether federalism consists of co-sovereign central and states governments or of sovereign central/weak subordinate governments. To discover the Founder’s attitudes writings of three periods were examined: 1) Marshall’s Marbury v. Madison opinion; 2) debates surrounding opinions in Martin v. Hunter’s Lessee, McCulloch v. Maryland, and Cohens v. Virginia; and 3) Andrew Jackson’s 1832 bank veto. Researching historical documents, to define conflicting terms, was important because it allowed an understanding of how the principles these terms represent relate to the United States Supreme Court (USSC), and was essential for a knowledgeable, impartial comparison. Major findings were that USSC rulings have largely defined the debate about The Constitution; that not even the extreme Federalist Alexander Hamilton believed the USSC was the sole and final arbiter of constitutional questions; and that today’s judiciary fulfills the Founders’ worst fears. In conclusion, at recent confirmation hearings stare decisis (precedent) was touted by some elected officials as the guiding principal of judicial decisions. In most instances, they referred only to recent precedents set over the past 50-60 years, while ignoring centuries-old precedents established at our nation’s founding. Implications are that unchecked, the judiciary will continue to discover “rights” lurking in the “shadows” of our Constitution. The judiciary is not solely to blame for this usurpation of We the People’s sovereignty. Through ignorance and indifference an unelected judiciary has been allowed to dominate our constitutional system. If the court has become the Super Branch, We the People are largely to blame. Education and involvement are a sure cure. URI: http://handle.tamu.edu/1969.1/4495 Files in this item: 1
The+FINAL+SUBMITTED++FATTUSSC+102406.pdf (1.058Mb) -
Nelson, John (August 16, 2006)[more][less]
Abstract: While the collapse of communist rule and process of transitioning to democracy in the former-Soviet Union and its numerous satellite states certainly warrants the wealth of attention received, by no means does this signal that the history of communist state rule is ended. Contrary to popular belief—and even belief in academe it sometimes seems—Communism still survives. In fact, a number of Asian states still claim to follow the path to a promised societal utopia under the guidance of their respective Politburos and may be described as not only ‘surviving’ but thriving, experiencing economic stability and enjoying high rates of growth. This study examines the ramifications of economic and political reform policies implemented by four collapsed communist regimes which have transitioned to democratic governance—the former-Soviet Union, Poland, Hungary, and Czechoslovakia—as well as two surviving Asian communist regimes—Vietnam and China—in identifying characteristic patterns of reform that are conducive to regime survival and/or collapse. The end objective herein is to provide projections for the future of the Castro regime in Cuba, which faces a critical juncture in the future with the impending death of its charismatic leader. I hypothesize that economic reform, through consistent implementation, generates credibility for both Communist Party elites and their future reform endeavors. Additionally, reform packages that manage to successfully stabilize the economy bestow an increased measure of legitimacy to the political elite, allowing the Communist Party to maintain political control, thereby avoiding collapse and the transition to democracy. The third and final section contains general discussion and what conclusions can be drawn from the results, as well as analysis of the history of reform efforts to present in the Caribbean island state of Cuba. URI: http://handle.tamu.edu/1969.1/3714 Files in this item: 1
Nelson - Fellows Thesis.doc (228.8Kb) -
Chateau, Morgan (August 24, 2008)[more][less]
Abstract: Chromosomal DNA in our cells is wrapped around a histone protein octomer like thread on a spool, forming a structure called a nucleosome. Series of nucleosomes form the nuclear chromosomes found in all eukaryotic organisms. Modifications to histone proteins can change how accessible chromosomal DNA is to protein complexes that act on DNA. DNA sequences that are inaccessible are called silent chromatin and regions that can’t be transcribed are subject to “gene silencing.” Proper gene silencing is necessary for normal cell development and regulation. Incorrect or missing histone modifications can cause the loss of gene silencing and uncontrolled gene expression similar to the situation in cells of patients with cancer or leukemia. My project focuses on a histone modifying complex COMPASS. COMPASS is composed of eight proteins, one of which is the histone H3 methyltransferase Set1. There are seven Set1 homologs in yeast and over 60 Set1-like proteins in humans, including MLL, which is known to be associated with human leukemia. Previous studies have shown that Set1 and most COMPASS proteins are essential for gene silencing at the ribosomal DNA locus (rDNA) in yeast. The SET domain is the active site of the Set1 histone methyltransferase, where methyl groups are covalently attached to the fourth lysine residue (K4) of histone H3. My goal is to investigate the effect of six individual amino acid substitutions in the SET domain of Set1; Y967A, I972A, Y993A, H1017L, Y967F, and G951A, on histone H3 methylation and gene silencing. These altered Set1 proteins are being expressed in the yeast Saccharomyces cerevisiae. Using Western blots and marker genes, the effect of these mutations are compared to wild type Set1. My data show that there are defects in histone H3 methylation in the amino acid substitution variants of Set1. In five of the mutants there is a complete loss of H3K4 methylation. In the future, we will determine if these altered Set1 proteins are assembled into the COMPASS complex. By characterizing the catalytic domain of Set1 using amino acid substitution variants, we will acquire a better understanding of the related proteins in humans. URI: http://handle.tamu.edu/1969.1/85749 Files in this item: 1
Thesis 2008 Final n.pdf (621.3Kb) -
Whitaker, Jodi (August 16, 2006)[more][less]
Abstract: This study examines how the genders of both student writers and their peer tutors affect the dynamics of writing tutoring sessions and influence the student writers’ subsequent evaluations of their peer tutors. Even though peer tutors employed the same non-directive, facilitative approach with all students, students judged female tutors to exhibit stereotypically feminine characteristics and male tutors to exhibit stereotypically masculine characteristics. Students also more highly evaluated the peer tutor whose sex matched their own. Students who were more highly sex-typed (masculine males and feminine females) more highly evaluated the same-sex peer tutor than did less sex-typed students of the same gender, though feminine female students more strongly exerted this preference than did masculine male students. Evidence gathered from post-session Likert surveys, paired observations, and semi-structured telephone interviews supported all three hypotheses. Reasons concerning why sex stereotypes still shape tutoring sessions as well as implications for altering tutor training policy are explored. URI: http://handle.tamu.edu/1969.1/3713 Files in this item: 1
Jodi Thesis (Modified).doc (1.054Mb) -
Petrich, Christine (August 16, 2006)[more][less]
Abstract: The eventual outcome of spinal cord injury is largely influenced by damage that occurs after the injury. Damaged connections between spinal cord cells and the brain allow a positive feedback mechanism to go unchecked when activated by ascending pain messages. Over-excitation then causes secondary damage. This study examines whether a pharmacological manipulation that should attenuate over-excitation reduces the adverse effects of shock treatment. Rats received spinal impact injuries and, the next day, were given the NMDA receptor antagonist MK-801 (0.08 mg/kg, i.p.) or its vehicle before receiving either a bout of uncontrollable stimulation or identical treatment without the stimulation itself. Their hindlimb motor activity was monitored for 21 days. Results indicate a significant effect of the drug on rats that received uncontrollable stimulation. The study has clinical implications for the treatment of spinal cord injuries in humans. URI: http://handle.tamu.edu/1969.1/3701 Files in this item: 1
PetrichThesis.pdf (329.8Kb) -
Propst, Matthew Stephen (September 10, 2008)[more][less]
Abstract: Multiple sclerosis (MS) is the most common inflammatory demyelinating disease of the central nervous system (CNS) affecting 1 in 2000 of the US population. Susceptibility to MS is influenced by environmental, gender, genetic and pathogenic factors. For instance, there is a higher incidence of MS in women than men (2:1) and that there is a sudden onset of the disease between the ages of 15 and 50, suggesting that gender, age and puberty alter the susceptibility to the disease. The etiology of MS is not known, and although viral infection is suspected to be an initiating event. Theiler’s murine encephalomyelitis virus (TMEV) infection in SJL mice causes a biphasic disease in which the chronic phase causes an inflammatory demyelinating disease of the CNS which closely resembles MS. In the current study we utilize TMEV to investigate the influence of both age and gender on disease progression in this viral model of human multiple sclerosis. Here, we tested the hypothesis that age and gender significantly affect the pathogenesis of Theiler’s virus-induced disease in which we showed that males displayed worse symptoms than females at later ages of inoculation. URI: http://handle.tamu.edu/1969.1/85755 Files in this item: 1
MSPropst-ResearchFellowsThesis.pdf (388.7Kb) -
Gajjar, Shefali Rajendra (May 21, 2008)[more][less]
Abstract: When prototrophic yeast cells undergo continuous growth in nutrient-limited conditions, they experience robust metabolic oscillations. Additionally, the processes of metabolism in yeast cells have been shown to be coordinated with cell division; cell division can only occur in certain phases of the metabolic cycle. It has been hypothesized that certain mutations that influence the rate of cell division may also affect yeast metabolic oscillations. Abf2p is a mitochondrial DNA maintenance protein; overexpression of Abf2p increases the rate of cell division, however, the effects of the overexpression of Abf2p on yeast metabolism are not known. Using a chemostat apparatus, metabolic oscillations, in terms of fluctuating dissolved oxygen concentrations, of Abf2p were obtained. Remarkably, the period of the metabolic oscillations of cells over-expressing Abf2p was more variable, but always longer than the period of wild-type cells. This was due to a clear expansion of the reductive phase. If the role of Abf2p in promoting cell division can be determined, a possible mechanism of controlling cell division may be established. URI: http://handle.tamu.edu/1969.1/6912 Files in this item: 1
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Mackey, Jessica (August 16, 2006)[more][less]
Abstract: Methylmercury has cytotoxic effects on animals and humans and a major target organ for methylmercury is the central nervous system (CNS). Methylmercury (MeHg) is a developmental neurotoxicant and the prenatal CNS appears to be even more sensitive to MeHg than the mature CNS. Previous research has shown that high doses of MeHg have severe cellular and behavioral effects. More recently, concern has been raised with respect to possible deleterious effects of chronic low doses of MeHg exposure to the developing CNS. The objective of this study was to determine if chronic low dose MeHg exposure would result in deficits in cognition and coordination and a decrease in mitochondrial membrane potential in cerebellar granule cells. Pregnant mice were divided into control and treatment groups. Developing fetuses were exposed to chronic low doses of MeHg through feeding food containing MeHg to pregnant C57Bl/6J female mice at a daily dose of 0.03 µg/Kg of body weight. Footprint analysis, rota-rod, vertical pole, open field and Morris water maze were used to test for changes in coordination, activity levels, spatial learning and memory. Differences were observed between control and MeHg groups in rota-rod, footprint analysis, open field and Morris water maze. The results follow below. Controls stayed on the rota-rod twice as long as treated mice on the last day of trials. Left and right foot angles were decreased in treated mice. Treated females displayed less rearing movement in the first five minutes of open field compared to both treated males and the controls. In the Morris water maze, treated mice took longer than controls to find the platform on days 1-4. The probe trial results indicated that treated mice swam significantly less than the controls. Cerebellar granule cells were isolated using dissociation media containing DNAse, and mitochondrial membrane potential was measured on the acutely isolated cells using tetramethylrhodamine methylester fluorescent dye. Images were captured with a fluorescence microscope. The data indicated no significant differences in fluorescence between control and MeHg mice. These conclusions indicate prenatal in vivo methylmercury exposure in mice may not significantly impair mitochondrial membrane potential; however, other abnormal neuronal functions lead to the subtle changes in motor and cognitive behavior described in this research. As a consequence, other cellular mechanisms must be delineated to understand how prenatal methylmercury exposure causes CNS pathogenesis. URI: http://handle.tamu.edu/1969.1/3712 Files in this item: 1
pdf thesis.pdf (945.2Kb)
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