2010 MU dissertations - Freely available online
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Item Computational and theoretical study of water and lipid dynamics in biomolecular systems(University of Missouri--Columbia, 2010) Jhuma, Das, 1980-; Kosztin, IoanThis Ph.D. thesis describes three research projects in theoretical and computational biophysics aimed at studying the dynamics of water and lipid molecules in two distinct biomolecular systems. In the first project the energetics and dynamics of water transport through the aquaglyceroporin (GlpF) channel protein is studied by a combination of all-atom molecular dynamics (MD) simulations (both equilibrium and non-equilibrium MD) and stochastic modeling. The MD results are used to determine the potential of mean force and the diffusion coefficient of water molecules crossing the channel. Then, the latter quantities are used to estimate the intrinsic water flux through GlpF, and the corresponding channel permeability. In the second project, by employing a 0.1 micro second long, all-atom MD simulation, the self and correlated dynamics of lipid atoms and molecules in a fully hydrated DMPC lipid bilayer is investigated. The MD simulation results are used to develop a memory function based approach for accurately calculating the lateral self-diffusion coefficient of lipids. In some cases, the proposed memory function method provides a better approach than the currently used ones for determining the lateral diffusion coefficient of lipids in lipid bilayers from the dynamic structure factor measured in inelastic neutron scattering experiments. The purpose of the third project is to investigate the dynamics of water molecules in a hydrated lipid membrane. Using the same MD simulation as in the second project, the anomalous properties of buried and hydration waters (located at the proximity of the fluctuating surface of the lipid membrane) are revealed and contrasted to the properties of bulk water.Item An ecological investigation of hangover severity and time course(University of Missouri--Columbia, 2010) Hunt-Carter, Erin, 1978-; Piasecki, Thomas Michael; Slutske, Wendy SueThe goal of the present study was to characterize the event-level severity and time course of hangover as it occurs naturalistically. Hangover symptoms were studied in a community sample of 402 adult regular drinkers (mean age=23.5, 50% female, 85% White). Participants carried palm-top computers for 21 days. They completed questionnaires upon waking, after drinking alcoholic beverages, smoking cigarettes, and randomly five times daily. Participants recorded 8,508 days of data. Each morning participants reported whether they were experiencing hangover. Reports of hangover were associated with increased sluggishness, headache, and nausea compared to post-drinking and post-abstinence days, and these effects persisted from 6:00 a.m. to midnight. Increased reports of dizziness were related to hangover, which persisted from 6:00 a.m. through 9:00 p.m. Hangover was also related to decreased enthusiasm and excitement compared to post-drinking days, these effects persisted until 3:00 p.m. As a whole, the findings suggest that hangover is a common consequence of heavy drinking that persists throughout the day after overindulgence. Results also demonstrate the utility of studying hangover using electronic diary designs.Item Physiological responses of continental (summer-active) and mediterranean (summer-dormant) tall Fescue to cold stress and identification of underlying QTL for fall growth and winter survival(University of Missouri--Columbia, 2010) Dierking, Ryan M., 1983-; Kallenbach, Robert L.; Sleper, D. A.We describe three experiments; the first two experiments were conducted in a greenhouse and with the use of cold chambers. The first experiment determined the effect of endophyte (Neotyphodium ceonophialum) presence under cold (4.5oC) and freezing (-3, -6, -9, and -12oC) conditions on two genotypes of Continental tall fescue [Lolium arundinaceum (Schreb.) S.J. Darbysh.], one Mediterranean tall fescue, and two F. arundinacea var. atlantigena St. Yves. The plants were assessed for growth, measured by leaf extension rate (LER), proline, fructan, and mono- and disaccharides concentrations at 25.0 and 4.5oC. Additionally, the survivability of these plants was assessed at -3, -6, -9, and -12oC. It was found that endophyte presence did not affect the LER or concentrations of proline and the mono- and disaccharides at 25.0 or 4.5oC. In the second experiment four Continental (PI 172423, PI 283297, PI 314684, and Kentucky-31) and three Mediterranean accessions (PI 200339, PI 610956, Flecha) were used to determine the growth quantified by LER, abscisic acid (ABA), proline, fructan, and mono- and disaccharides concentrations. Mediterranean accessions were different from Continental accessions for all parameters measured at 4.5oC. The final experiment included the development of a linkage map from a cross between a Mediterranean (103-2) x Continental (R43-64) cross, and identifying QTL relating to fall growth (FG), measured by LER, and winter survival (WS). This is the first reported linkage map of Mediterranean tall fescue as well as the use of DArTFest markers using array technology. Major QTL were found for FG and WS at each location across years. Based on all data in this study it appears these two types of tall fescue are unique species.Item Pathway approaches to dissecting the inheritance of maize shoot-borne roots(University of Missouri--Columbia, 2010) Gerau, Michael, 1980-; Davis, Georgia L.Shoot-borne roots are essential plant components. Two pathway-based approaches were pursued to increase our understanding of genetic mechanisms controlling shoot-borne root patterning. The first pathway approach characterized the contribution of gibberellic acid-related genes in shoot-borne root patterning. Quantitative trait loci mapping in the Intermated B73xMo17 linkage mapping population identified chromosome regions controlling shoot-borne root patterning which also contained gibberellic acid biosynthetic and response genes. Phenotyping of mutants with altered gibberellic acid production and response validated these genes as potentially underlying the identified quantitative trait loci. Association analysis was conducted in a set of 260 diverse maize inbred lines. The association analysis identified significant polymorphisms in the catalytic domain of the gibberellic acid biosynthetic gene dwarf3 and in the promoter region of the gibberellic acid response regulator Dwarf8. These results confirmed the previous hypothesis that gibberellic acid production is involved in shoot-borne root patterning and expanded it to include DELLA-mediated gibberellic acid response. In the second pathway-based approach a multivariate phenotypic analysis was conducted on 25 diverse maize inbred lines that were phenotyped for 23 developmental traits along with three shoot-borne root traits to define novel hypotheses about pathways involved in shoot-borne root patterning,. Evidence for a light-signaling component in root development was found. Further support for the involvement of light-signaling was provided by mutant phenotyping and field experiments which confirmed the predictions of the multivariate analysis. The two pathways were integrated into one model where light-mediated redistribution of gibberellic acid dictates shoot-borne root patterning.Item Identification of perceptions of reincarcerated men concerning community reintegration life experiences in Missouri as measured by the Community Reentry Survey and prediction of group membership(University of Missouri--Columbia, 2010) Berry, Meridith J. Hembree; Messner, Phillip E. (Phillip Eugene), 1941-Recidivism is a serious problem in the United States as well as Missouri. According to the 2008 Missouri Probation and Parole Annual Report, 108,787 people were under supervision of Missouri Probation and Parole at some point in FY 2008. That same year in Missouri, 15,256 people violated the conditions of probation or parole and were incarcerated. The good news is, the rate is decreasing. However, the current recidivist trend data indicates approximately 24,500 will return to prison by 2011. The cost of incarceration is measured not only in dollars, but is also measured in absent parents, loss of productivity, and in loss of potential. Various programs are in place to rehabilitate offenders to give them the tools to successfully integrate into the community. This quantitative study examines the perceptions about life situations of reincarcerated men in a Missouri correctional institution. The literature review includes a brief history of the penal system. The methods used in this study included a survey tool, Community Reentry Survey, which was administered to incarcerated volunteers. Findings indicated the source of problems for ex-offenders as they tried to reintegrate in the community included substance abuse, ability to find employment, and old friends and acquaintances.