UMD Theses and Dissertations

Permanent URI for this collectionhttp://hdl.handle.net/1903/3

New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a given thesis/dissertation in DRUM.

More information is available at Theses and Dissertations at University of Maryland Libraries.

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Subject: search.filters.subject.Elevated CO2

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    High-Throughput Time Series Metabolomic Analysis of a Systematically Perturbed Plant System
    (2007-04-27) Kanani, Harin H; Klapa, Maria I; Chemical Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    In the post-genomic era, availability of high-throughput profiling techniques enabled the measurement of entire cellular molecular fingerprints. Major characteristics of the high-throughput revolution were that (a) studying biological problems did not have to rely on prior hypotheses, while (b) parallel occurring phenomena, previously assumed disconnected, could now be simultaneously observed. Metabolomics is the newest of the "omics" techniques. It enables the quantification of hundreds of free metabolite pools, providing a metabolic fingerprint. Considering the importance of cellular metabolism, which is the net effect of changes at the genomic, transcriptomic and proteomic levels and of the cell with its environment, the metabolomic profile, is a fundamental determinant of cellular physiology. Obtaining accurate and complete metabolomic profiles is thus of great importance. However, being recent technology, metabolomics is currently at its standardization phase. As part of my PhD thesis research, I focused on addressing several current challenges in metabolomics technology development. Specifically a novel data correction, validation and normalization strategy for gas chromatography-mass spectrometry (GC-MS) metabolomic profiling analysis was developed, which dramatically increased the accuracy and reliability of GC-MS metabolomic profiles. The optimized metabolomics protocol was applied to study the short-term dynamic response of systematically perturbed Arabidopsis thaliana liquid culture system to study regulation of its primary metabolism. The biological system was studied under conditions of elevated CO2 stress, salt (NaCl) stress, sugar (trehalose) signal, and hormone (ethylene) signal, applied individually; the latter three stresses also applied in combination with the CO2 stress. Analysis of the obtained results required the appropriate application of multivariate statistical analysis techniques, which are developed mainly in transcriptomic analysis, into metabolomics analysis for the first time. The acquired results identified important new regulatory information about the biological systems resulting in new targets for metabolic engineering of plants. The large number of dynamic perturbation allowed re-construction of metabolic networks to identify possible novel metabolic pathways based on correlations between metabolic profiles. In addition, it demonstrates the advantages of dynamic, multiple-stress "omic" analysis for the elucidation of plant systems function. In this sense, it contributes in further advancing the computational and experimental metabolic engineering and systems biology toolbox.
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    TIME SERIES METABOLIC PROFILING ANALYSIS OF THE SHORT TERM Arabidopsis thaliana RESPONSE TO ELEVATED CO2 USING GAS CHROMATOGRAPHY MASS SPECTROMETRY.
    (2004-08-30) Kanani, Harin Haridas; Klapa, Maria I; Chemical Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Metabolic profiling has emerged as a high throughput technique for the quantitative analysis of the cellular physiological state at the metabolic level. It allows for the simultaneous relative quantification of hundreds of low molecular weight intra cellular metabolites. In this analysis, the polar metabolic profiles of A. thaliana liquid cultures (grown for 12 days, under light and 23°C) throughout 1-day treatment with 1% CO2, were measured using gas chromatography-mass spectrometry. Despite the advantages of time series analysis, this is the first plant metabolic profiling study of this type reported in the literature. The time series metabolic profiles were analyzed using multivariate statistical techniques. Data analysis revealed repression of photorespiration, repression of nitrogen assimilation and increase in structural carbohydrates. It is for the first time that the latter phenomenon is observed as a result of elevated CO2 in the plant environment.