Global ETD Search

141	The Expanding Diversity of Plant U-box E3 Ubiquitin Ligases in Arabidopsis: Identifying AtPUB18 and AtPUB19 Function during Abiotic Stress Responses Yee, Donna 17 February 2011 (has links) The ability of plants to sense and respond to environmental and endogenous signals is essential to their growth and development. As part of these diverse cellular functions, ubiquitin-mediated proteolysis has emerged to be an important process involved in how plant signalling pathways can be regulated in response to such cues. Of the three enzymes involved in linking ubiquitin to protein targets, E3 ubiquitin ligases are of interest as they confer substrate specificity during this ubiquitination process. The overall focal point of this research is on plant U-box (PUB) E3 ubiquitin ligases, a family that has undergone a large gene expansion possibly attributable to the regulation of biological processes unique to the plant life cycle. In Arabidopsis there are 64 predicted PUBs, many for which biological roles have yet to be determined. And as research continues to uncover PUB functions, the functional diversity in the gene family will likely expand. Specifically the focus of this research is on characterizing two ARM repeat-containing PUBs – AtPUB18 and AtPUB19. General analysis of pub18 and pub19 T-DNA insertion lines for growth defects did not yield distinct altered phenotypes. Closer inspection of selected lines showed independent gene assortment phenotypes that, with further inordinately convoluted pursuit, proved to have an AtPUB18/19-unrelated outcome. The availability of Arabidopsis microarray databases provided exploratory expression profiling as a starting point to elucidate PUB function. AtPUB19 and closely related AtPUB18 are notable for their increased expression during abiotic stresses. While condition-directed germination assays showed a decreased sensitivity to salt and ABA for pub18 pub19 double insertion lines, no related change in susceptibility to these or other abiotic stress treatments were seen with condition-directed root growth assays. Thus, this preliminary work has begun to reveal insight into the complex abiotic stress-related roles AtPUB18 and AtPUB19 have during mediation of environmental stress acclimation in Arabidopsis. ubiquitination E3 ubiquitin ligase Arabidopsis U-box plant U-box degradation abiotic stress ABA salinity germination root elongation non-Mendelian segregation T-DNA insertions 26S proteasome programmed cell death leaf senescence bioinformatics microarrays Bio-Array Resource ovule abortion pollen collapse DEX rescue chlorophyll retention double mutant generation higher order knock-outs partial redundancy 0309 0715 0307
142	Validation of de novo Bioinformatic Predictions of Arabidopsis thaliana Cis-regulatory Elements using in planta GUS Expression Assays Hiu, Shuxian 19 July 2012 (has links) The study of cis-regulatory elements (CREs) will allow for increased understanding of regulation and lead to insight regarding the mechanisms governing growth, development, health, and disease. The aim of this study was to characterize the de novo in silico predictions of Arabidopsis CREs. Eight synthetic and 30 native promoter-constructs containing an eGFP/GUS reporter protein were generated for cold, genotoxic, heat, osmotic, and salt stress; the circadian clock; ABA signaling; root and epidermis tissue. Constructs were stably transformed into A. thaliana Col-0 and the effects of the CREs were evaluated by in planta stress or tissue assays using GUS expression levels. Results reveal a novel genotoxic element that specifically directs GUS expression in rosette leaves during genotoxic stress. Results also look promising for novel epidermis and root-specific elements. Results of these assays validate the de novo prediction pipeline's ability to identify novel and known CREs related to abiotic stress. cis-regulatory elements bioinformatics GUS cold stress enhancer silencer insulator local control regions (LCRs) MARs/SARs in planta evening element circadian rhythm arabidopsis genotoxic bleomycin mitomycin c heat stress stem epidermis root abscisic acid (ABA) osmotic stress salt stress synthetic constructs expression assays transcription factor binding sites CaMV35S columbia-0 0306 0715 0309 0379 0307
143	Validation of de novo Bioinformatic Predictions of Arabidopsis thaliana Cis-regulatory Elements using in planta GUS Expression Assays Hiu, Shuxian 19 July 2012 (has links) The study of cis-regulatory elements (CREs) will allow for increased understanding of regulation and lead to insight regarding the mechanisms governing growth, development, health, and disease. The aim of this study was to characterize the de novo in silico predictions of Arabidopsis CREs. Eight synthetic and 30 native promoter-constructs containing an eGFP/GUS reporter protein were generated for cold, genotoxic, heat, osmotic, and salt stress; the circadian clock; ABA signaling; root and epidermis tissue. Constructs were stably transformed into A. thaliana Col-0 and the effects of the CREs were evaluated by in planta stress or tissue assays using GUS expression levels. Results reveal a novel genotoxic element that specifically directs GUS expression in rosette leaves during genotoxic stress. Results also look promising for novel epidermis and root-specific elements. Results of these assays validate the de novo prediction pipeline's ability to identify novel and known CREs related to abiotic stress. cis-regulatory elements bioinformatics GUS cold stress enhancer silencer insulator local control regions (LCRs) MARs/SARs in planta evening element circadian rhythm arabidopsis genotoxic bleomycin mitomycin c heat stress stem epidermis root abscisic acid (ABA) osmotic stress salt stress synthetic constructs expression assays transcription factor binding sites CaMV35S columbia-0 0306 0715 0309 0379 0307
144	The Expanding Diversity of Plant U-box E3 Ubiquitin Ligases in Arabidopsis: Identifying AtPUB18 and AtPUB19 Function during Abiotic Stress Responses Yee, Donna 17 February 2011 (has links) The ability of plants to sense and respond to environmental and endogenous signals is essential to their growth and development. As part of these diverse cellular functions, ubiquitin-mediated proteolysis has emerged to be an important process involved in how plant signalling pathways can be regulated in response to such cues. Of the three enzymes involved in linking ubiquitin to protein targets, E3 ubiquitin ligases are of interest as they confer substrate specificity during this ubiquitination process. The overall focal point of this research is on plant U-box (PUB) E3 ubiquitin ligases, a family that has undergone a large gene expansion possibly attributable to the regulation of biological processes unique to the plant life cycle. In Arabidopsis there are 64 predicted PUBs, many for which biological roles have yet to be determined. And as research continues to uncover PUB functions, the functional diversity in the gene family will likely expand. Specifically the focus of this research is on characterizing two ARM repeat-containing PUBs – AtPUB18 and AtPUB19. General analysis of pub18 and pub19 T-DNA insertion lines for growth defects did not yield distinct altered phenotypes. Closer inspection of selected lines showed independent gene assortment phenotypes that, with further inordinately convoluted pursuit, proved to have an AtPUB18/19-unrelated outcome. The availability of Arabidopsis microarray databases provided exploratory expression profiling as a starting point to elucidate PUB function. AtPUB19 and closely related AtPUB18 are notable for their increased expression during abiotic stresses. While condition-directed germination assays showed a decreased sensitivity to salt and ABA for pub18 pub19 double insertion lines, no related change in susceptibility to these or other abiotic stress treatments were seen with condition-directed root growth assays. Thus, this preliminary work has begun to reveal insight into the complex abiotic stress-related roles AtPUB18 and AtPUB19 have during mediation of environmental stress acclimation in Arabidopsis. ubiquitination E3 ubiquitin ligase Arabidopsis U-box plant U-box degradation abiotic stress ABA salinity germination root elongation non-Mendelian segregation T-DNA insertions 26S proteasome programmed cell death leaf senescence bioinformatics microarrays Bio-Array Resource ovule abortion pollen collapse DEX rescue chlorophyll retention double mutant generation higher order knock-outs partial redundancy 0309 0715 0307
145	Effects of Air vs. Air+Soil Heating During a Simulated Heat Wave on White Oak (Quercus alba) and Black Oak (Quercus velutina) Lightle, Nicole E. 22 August 2013 (has links) No description available. Ecology Environmental Science Forestry Physiology Plant Sciences Plant Biology Urban Forestry acute heat heat stress heat wave extreame weather soil heating superoptimal temperature root zone temperature global climate change white oak black oak Quercus forest mortality thermotolerance photosynthesis root respiration ABA

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