Thesis (Master, Biology) -- Queen's University, 2009-09-10 13:10:31.576 / Ca2+ ions participate as second messengers in many stress-response and developmental pathways. Among eukaryotes, plants possess a remarkable diversity of Ca2+ binding proteins (Ca2+ sensors) such as calmodulin (CaM) and CaM-related proteins (CMLs) that regulate downstream targets and coordinate signal transduction events in response to stimuli. Previous studies have shown that a small subfamily of CMLs (CML37, CML38, CML39) in Arabidopsis show differential tissue expression as well as a dramatic induction of expression in response to environmental stress. For example, CML37 and CML38 respond very strongly to wounding, while CML39 is induced significantly by jasmonate. In order to understand the underlying regulatory mechanisms of the genes, promoter analysis experiments using the 5 upstream regions of these CMLs driving -glucuronidase (GUS) reporter expression were conducted. This empirical approach is a critical complement to algorithm-based prediction methods. It was found that the gateway vector pMDC163 was unsuitable for 5 deletion analyses. Three regions within the CML37 promoter were identified as having wound-responsiveness. Several known wound-responsive cis-elements were identified in these regions. A putative cis-element that is overrepresented in genes coexpressed with CML37 was also identified. Together, these data should lay the groundwork to identify the transcriptional regulators that direct stress-responsive CML gene expression. / Master

statistics, 2) unadjusted inferential statistics, 3) stratified analysis, and 4) multivariable models. My investigation produced results in accord with generally accepted notions in addition to significant findings that interestingly counter current preconceptions. Intraspecies contact was more common than inter-species, with indirect contact occurring more frequently than direct. Direct contact between species occurred extremely rarely. The most important factors that influenced the rate of contact for both species were water, winter, and cultivated fields. Information regarding probability of infectious agent survival and transfer will be used in the future to advance current epidemiological models, including geographicautomata (Ward et al. 2007: In Press) and cellular automata models (Doran and Laffan 2005) to better understand and manage integrated domestic cattle and free-ranging wildlife populations. Such modeling provides essential and necessary knowledge for developing prevention, detection, response, and recovery strategies – employed in advance, during, and after a disease outbreak, respectively. responsible for telomere activation. In addition tac5 showed sensitivity to hydrogen peroxide treatment, suggesting a novel role of telomerase in the mitochondrial environment. Chapter III reports the role of PARP proteins in plant telomere biology. Both AtPARP1 and AtPARP2 are transcriptionally upregulated in response to DNA damage treatment or telomere dysfunction. However, in contrast to mammalian PARPs, the Arabidopsis proteins do not appear to have a function in telomere length maintenance as indicated by TRF analysis or in promoting genome stability maintenance as indicated by cytogenetic studies. Further analysis of PARP interactions at dysfunctional telomeres in the genetically tractable Arabidopsis model may provide insight into the cellular response to dysfunctional telomeres. As explained in chapter IV, the yeast two-hybrid screen was utilized to confirm the interactions of ATR with AtPOT2 and Ku80 and to identify novel interacting partners of Arabidopsis telomere proteins. At2g04410 (Unknown protein) was identified as a direct interacting partner of AtPOT1. This interaction was confirmed in vitro by coimmunoprecipitation assay. Further analysis of the unknown protein may shed light on AtPOT1’s function in telomere maintenance.

Title from PDF of title page (University of Missouri--Columbia, viewed on Feb. 12, 2008). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Dr. Shuqun Zhang, Thesis Supervisor. Vita. Includes bibliographical references.

Arabidopsis thaliana purple acid phosphatase 2 (AtPAP2) is a phosphatase dually targeted to both chloroplasts and mitochondria. Overexpression (OE) of AtPAP2 in Arabidopsis thaliana was reported to speed up plant growth and promote flowering, seed yield and biomass at maturity in a previous study. Under long-day (16 hours light at 22°C / 8 hours dark at 18°C) growth conditions, the leaves of 20-day-old OE lines contained significant higher sucrose and glucose than the wild-type (WT) plants, reflecting their high energy status. The AtPAP2 OE line is thus a good model to investigate the impact of high energy on the global physiological changes in Arabidopsis. In this study, the systems biology of the high-energy plants, in terms of transcriptome, proteome, metabolome and small RNA (sRNA) expression profiles were examined. Liquid chromatography mass spectrophotometry (LC-MS/MS) and enzyme assays were both employed to measure the content of ADP/ATP/NAD/NADP/NADPH in the leaves of 20-day-old OE and WT lines at 3 time points (t = 0, end of night; t = 1, 1 h after light was on; t = 8, 8 h after light was on). My results showed that the ATP and ADP contents were significantly increased in the OE line at all the three time points. In the dark, since mitochondria is the major source of ATP supply in plant cells, the comparison of omics data between the OE and WT lines at t = 0 reflected the impact of high ATP output from mitochondria on plant leaves. Similarly, the comparison between the OE and WT lines at t = 8 reflected the impact of higher ATP output from chloroplast of plant leaves. By RNA sequencing (RNA-Seq) technology, transcriptome profiles between OE and WT at all the three time points (t = 0, 1, and 8 h after illumination) were compared. The transcripts of 29,435 genes were detected in all six datasets. Moreover, transcripts encoded by the chloroplast and mitochondrial genomes, which were not reported in the previous microarray studies were also sequenced. Genes of the central energy conversion pathways that were differentially transcribed between the OE and WT lines were identified. In proteomics studies, 2663 proteins were identified by the isobaric tags for relative and absolute quantification (iTRAQ) labeled technique. The proteins with significantly altered in protein abundances (P < 0.05) in various energy pathways, including photosynthesis, redox regulation, Calvin-Benson cycle, carbohydrate metabolism, glycolysis, tricarboxylic acid (TCA) cycle and the respiratory system in mitochondria, were identified. When the transcriptomes and proteomes were compared, the correlation between mRNA transcript and protein abundances was not high. Small RNA studies showed that the expression of miR173, which initiates the generation of tasiRNAs from TAS1 and TAS2 loci, was significantly increased in the leaves of OE lines. These tasiRNAs target the mRNAs of various pentatricopeptide repeat (PPR) and tetratricopeptide repeat (TPR) proteins, which control RNA metabolism in chloroplasts and mitochondria. A network of miR173-tasiRNAs-PPR/TPR was established to present the changes in the OE lines. In summary, my study systematically investigated the global impact of high energy status to the metabolome, transcriptome, proteome and sRNAs profiles of Arabidopsis. Two diagrams were presented to illustrate the impacts of high energy status on the physiology of leaf cells under light and dark conditions, respectively. / published_or_final_version / Biological Sciences / Doctoral / Doctor of Philosophy

published_or_final_version / Botany / Master / Master of Philosophy

Activation-tagging is a powerful functional genomics technique used to identify plant genes and their functions. The random introduction of gene enhancers into the plant genome results in the overexpression of nearby genes, thus the gene responsible for a mutant phenotype can be determined based on the location of the enhancers. In a screen for activation-tagged Arabidopsis lines with aberrations in trichome morphology, a mutant (named P330) with unbranched trichomes was identified. In this thesis, the actin- encoding gene ACT11 was found to be upregulated by T-DNA pSKI015 in P330. Additionally, this line also produces a second mutant phenotype, characterized by a significant reduction in seed set. The findings presented in this thesis build upon previous work that has shown ACT11 is strongly expressed in reproductive organs (such as pollen and ovules) and rapidly elongating tissues in Arabidopsis. The role of actin has been characterized in Arabidopsis trichome morphogenesis, however much remains unclear about actin dynamics in sexual reproduction. Our investigation on the effects of increased ACT11 expression adds to our understanding of these processes and also provides the framework for future studies into trichome morphogenesis and sexual reproduction in flowering plants. / Thesis (Master, Biology) -- Queen's University, 2014-06-24 15:14:59.429

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv. / Härtill 4 uppsatser.

Thesis (Ph.D.) -- University of Adelaide, 1955. / Typewritten copy.

Thesis (M. Phil.)--University of Hong Kong, 1998. / Includes bibliographical references (leaf 89-94).

Thesis (M.Sc.)--York University, 2008. Graduate Programme in Biology. / Typescript. Includes bibliographical references (leaves 52-57). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:MR51521