Дисертації з теми "Plant biology not elsewhere classified"
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He, Bai-sen. "Osmotic dehydration in plant tissues." Thesis, Aston University, 2005. http://publications.aston.ac.uk/12236/.
Повний текст джерелаAl-Khawaja, Nasreen. "Quality of life, biomarkers, and involvement of ghrelin in women with breast cancer." Thesis, University of Central Lancashire, 2015. http://clok.uclan.ac.uk/16593/.
Повний текст джерелаHatchell, Hayley. "The relationship between docohexanoic acid (DHA) and L-serine, providing an insight into the biochemistry of meningioma." Thesis, University of Central Lancashire, 2017. http://clok.uclan.ac.uk/23985/.
Повний текст джерелаMitchell, Anthony Frank. "An investigation into the microbial bioconversion of cellulosic waste." Thesis, University of Central Lancashire, 1986. http://clok.uclan.ac.uk/19063/.
Повний текст джерела(9897308), SM Brown. "Solute transport within the legume nodule." Thesis, 1996. https://figshare.com/articles/thesis/Solute_transport_within_the_legume_nodule/13462247.
Повний текст джерела(11799615), Peter John Brown. "Studies on the epidemiology and other aspects of Chalara elegans." Thesis, 1999. https://figshare.com/articles/thesis/Studies_on_the_epidemiology_and_other_aspects_of_Chalara_elegans/17132273.
Повний текст джерела(12547368), John Kingsley Hall. "The effect of plant density and photoperiod on flowering time, growth and yield of subtropical hemp (Cannabis sativa L.)." Thesis, 2012. https://figshare.com/articles/thesis/The_effect_of_plant_density_and_photoperiod_on_flowering_time_growth_and_yield_of_subtropical_hemp_Cannabis_sativa_L_/19769239.
Повний текст джерелаIndustrial hemp (Cannabis sativa L.) production is experiencing a significant increase in worldwide production since regaining popularity in many countries since the 1990's. Currently, production in Australia is very limited, and no major grain or fibre processing facilities yet exist, owing to the lack of suitable low THC (A9-tetrahydrocannibinol) varieties. Hemp production in subtropical regions of Australia is particularly limited as short day lengths (photoperiods) result in early plant maturity, and thus, poor yielding crops. The aim of this research is to determine the viability of a new variety of hemp, bred specifically for subtropical production whilst determining the effects of day length and plant density on yield and flowering time. Trials were conducted in Bundaberg, QLD in 2010-2012 in both field and controlled environment (plastic house) settings. Plant densities of 100, 200, 300 and 400 plants m-2 were compared for fibre production and densities of 50, 80, 100 and 150 plants m2 were compared for grain production to assist in the establishment of appropriate commercial sowing rates. Harvested fibre yields were greatest at 300 plants m2 whereas grain yields were greatest at 150 plants m2, with the potential of even higher yields at densities greater than 150 plants m2. Photoperiod experiments were conducted in a controlled plastic house evaluating plant responses to varying photoperiods. Treatments comparing ambient day length, 13 hour 40 minute fixed photoperiod and 14 hour 40 minute fixed photoperiod determined that a 13 hour 40 minute photoperiod did not significantly prolong vegetative growth compared to natural day lengths in the hemp variety BundyGem but at 14 hours 40 minutes maturity times were significantly delayed, thereby contributing to greater plant height and fibre yield. Previous research also suggests that a critical photoperiod of between 14 and 16 hours is required before flowering is delayed in hemp. This theory was supported by a field experiment whereby successive plantings of BundyGem throughout the spring/summer period of 2011/2012, flowered at the same age despite subtle changes in day length for the growing period (never exceeding 13 hours 40 minutes). This research confirms that subtropical fibre hemp is not yet suitable for subtropical production in Australia with existing varieties due to the limitation of photoperiod on yield. Grain production may still be viable despite early plant maturity with yields comparable with those produced in Europe and Canada.
(9525857), Fabiola Muro Villanueva. "Re-routing the phenylpropanoid pathway and its implications on plant growth." Thesis, 2020.
Знайти повний текст джерелаThe phenylpropanoid pathway gives rise to a wide variety of specialized metabolites, but the majority of carbon flux going through this pathway is directed towards the synthesis of the lignin monomers: p-coumaryl alcohol, coniferyl alcohol and sinapyl alcohol. Lignin is a major impediment in biomass saccharification, which negatively affects animal feed and biofuel production. In an effort to improve biomass for the latter purposes, researchers have altered the polymer through genetic manipulations and generated biomass with lower recalcitrance to saccharification; however, in many cases these efforts have resulted in plant dwarfism. To date, we do not have a full understanding of the extent of lignin modifications a plant is able to tolerate without affecting its growth. More importantly, the mechanism that links dwarfism and modifications in lignin content and composition remains unknown. To contribute to answering these questions, we designed a strategy to incorporate a novel monomer into the lignin of Arabidopsis thaliana. We used mutants in genes that code for enzymes and regulators of the phenylpropanoid pathway to redirect the pathway’s flux towards the synthesis of p-coumaraldehyde and prevent the incorporation of p-coumaryl alcohol. Despite being mutated for the genes typically considered to be required for monolignol biosynthesis, the plants we generated continue to incorporate p-coumaryl alcohol into their lignin. This result suggests that the pathway’s architecture has not been completely elucidated and that there are more enzymes involved in lignification than previously thought. Additionally, we explored the connection between perturbations in phenylpropanoid metabolism and plant growth, by using an inducible system to track the changes in gene expression and metabolism that occur when phenylpropanoid metabolism is restored in a lignin biosynthetic mutant. The use of an inducible system allowed us to not only determine the metabolic processes affected in this mutant, but the proximal sequence of events that lead to restored growth when a functional copy of the mutant gene is induced. Finally, we redirected the flux through the pathway to assess the effects of simultaneously modulating lignin content and composition. Through this project we discovered that redirecting phenylpropanoid flux towards the synthesis of sinapyl alcohol in lignin-deficient mutant backgrounds, results in plant dwarfism. The growth impairment of these mutants can be overcome by providing exogenous coniferyl alcohol, suggesting that dwarfism in these mutants is caused by deficiency in coniferyl alcohol and/or derivatives thereof and not lignin alone. Altogether these projects allowed us to define the cellular processes affected by perturbations in phenylpropanoid homeostasis and the role of other phenylpropanoids besides lignin in this process.
(9815696), Sandrine Makiela. "Studies on dieback of buffel grass (Cenchrus ciliaris) in Central Queensland." Thesis, 2008. https://figshare.com/articles/thesis/Studies_on_dieback_of_buffel_grass_Cenchrus_ciliaris_in_Central_Queensland/13426124.
Повний текст джерела(9874763), C. Mills. "An investigation into the role of oxalate in the leaves of Pisonia grandis." Thesis, 1991. https://figshare.com/articles/thesis/An_investigation_into_the_role_of_oxalate_in_the_leaves_of_Pisonia_grandis/13424555.
Повний текст джерела(6634556), Longyun Guo. "Mathematical modeling of phenylalanine and lignin biosynthetic networks in plants." Thesis, 2019.
Знайти повний текст джерела(6714896), Xiangying Mao. "INVESTIGATING THE FUNCTIONAL ROLE OF MED5 AND CDK8 IN ARABIDOPSIS MEDIATOR COMPLEX." Thesis, 2019.
Знайти повний текст джерелаThe Mediator (Med) complex comprises about 30 subunits and is a transcriptional co-regulator in eukaryotic systems. The core Mediator complex, consisting of the head, middle and tail modules, functions as a bridge between transcription factors and basal transcription machinery, whereas the CDK8 kinase module can attenuate Mediator’s ability to function as either a co-activator or co-repressor. Many Arabidopsis Mediator subunit has been functionally characterized, which reveals critical roles of Mediator in many aspects of plant growth and development, responses to biotic and abiotic stimuli, and metabolic homeostasis. Traditional genetic and biochemical approaches laid the foundation for our understanding of Mediator function, but recent transcriptomic and metabolomic studies have provided deeper insights into how specific subunits cooperate in the regulation of plant metabolism. In Chapter 1, we highlight recent developments in the investigation of Mediator and plant metabolism, with emphasis on the large-scale biology studies of med mutants.
We previously found that MED5, an Arabidopsis Mediator tail subunit, is required for maintaining phenylpropanoid homeostasis. A semi-dominant mutation (reduced epidermal fluorescence 4-3, ref4-3) that causes a single amino acid substitution in MED5b functions as a strong suppressor of the pathway, leading to decreased soluble phenylpropanoid accumulation, reduced lignin content and dwarfism. In contrast, loss of MED5a and MED5b (med5) results in increased levels of phenylpropanoids. In Chapter 2, we present our finding that ref4-3 requires CDK8, a Mediator kinase module subunit, to repress plant growth even though the repression of phenylpropanoid metabolism in ref4-3 is CDK8-independent. Transcriptome profiling revealed that salicylic acid (SA) biosynthesis genes are up-regulated in a CDK8-dependent manner in ref4-3, resulting in hyper-accumulation of SA and up-regulation of SA response genes. Both growth repression and hyper-accumulation of SA in ref4-3 require CDK8 with intact kinase activity, but these SA phenotypes are not connected with dwarfing. In contrast, mRNA-sequencing (RNA-seq) analysis revealed the up-regulation of a DNA J protein-encoding gene in ref4-3, the elimination of which partially suppresses dwarfing. Together, our study reveals genetic interactions between Mediator tail and kinase module subunits and enhances our understanding of dwarfing in phenylpropanoid pathway mutants.
In Chapter 3, we characterize other phenotypes of med5 and ref4-3, and find that in addition to the up-regulated phenylpropanoid metabolism, med5 show other interesting phenotypes including hypocotyl and petiole elongation as well as accelerated flowering, all of which are known collectively as the shade avoidance syndrome (SAS), suggesting that MED5 antagonize shade avoidance in wild-type plants. In contrast, the constitutive ref4-3 mutant protein inhibits the process, and the stunted growth of ref4-3 mutants is substantially alleviated by the light treatment that triggers SAS. Moreover, ref4-3 mimics the loss-of-function med5 mutants in maintaining abscisic acid (ABA) levels under both normal and drought growth conditions. The phenotypic characterization of med5 mutants extend our understanding of the role of Mediator in SAS and ABA signaling, providing further insight into the physiological and metabolic responses that require MED5.
In Chapter 4, we explore the function of MED5 and CDK8 in gene expression regulation by investigating the effect of mutations in Mediator including med5, ref4-3, cdk8-1 and ref4-3 cdk8-1 on genome-wide Pol II distribution. We find that loss of MED5 results in loss of Pol II occupancy at many target genes. In contrast, many genes show enriched Pol II levels in ref4-3, some of which overlap with those showing reduced Pol II occupancy in med5. In addition, Pol II occupancy is significantly reduced when CDK8 is disrupted in ref4-3. Our results help to narrow down the direct gene targets of MED5 and identify genes that may be closely related to the growth deficiency observed in ref4-3 plants, providing a critical foundation to elucidate the molecular function of Mediator in transcription regulation.
(11205324), Benjamin Joseph Rivera. "The Establishment, Control, and Post-Control Response of Amur Honeysuckle (Lonicera maackii)." Thesis, 2021.
Знайти повний текст джерелаAmur honeysuckle (Lonicera maackii) is a shrub endemic to East Asia which has become invasive and nearly ubiquitous to the forest ecosystems of eastern North America. Through its extended growing season, competitive ability, and potential allelopathy, Amur honeysuckle alters native herbaceous-layer plant communities and inhibits the regeneration of native tree species. As such, it is representative of a range of invasive shrub species imported from East Asia. My thesis contributes to questions fundamental to the understanding this and other invasive shrubs: 1) How do species become invasive? 2) How can the invasions of the species be effectively controlled? 3) How does the ecosystem respond to treatment of the invasive species?
First, I examined the role of self-compatibility within Amur honeysuckle. I compared the berry production, seed production, and germination rates between closed-pollinated and open-pollinated flowering branches of Amur honeysuckle individuals across multiple types of invasions (heavy, light, and sprouting). I found that Amur honeysuckle not only possesses the ability to self-pollinate, but that it can produce viable self-pollinated seed sets. This ability may help explain how Amur honeysuckle able to invade isolated forest patches far removed from the main invasion.
Second, I evaluated the effectiveness of a novel herbicide adjuvant in reducing the amount of herbicide needed in the ‘cut-stump’ method of controlling Amur honeysuckle. Combining various concentrations of the most common herbicide in the world, glyphosate, with concentrations of cellulases derived from fungi, 2XL, I examined whether the cellulases improved the effectiveness of glyphosate, potentially by increasing glyphosate movement into the vascular tissue of Amur honeysuckle through the degradation of cell walls. While 2XL was not an effective adjuvant, glyphosate concentrations of less than half the recommended dosages were equally effective as higher concentrations in preventing sprouting of treated stumps. The ineffectiveness of 2XL may imply a need for protein-mitigated diffusion of glyphosate across cell walls and into the vascular tissue of the plant, which would be inhibited by the breakdown of cell walls.
Finally, I tested how deeper intensities of mulching-head treatments affected the sprouting response of Amur honeysuckle and the response of the herbaceous-layer plant community after treatment. I found a negative relationship between the volume of sprouting Amur honeysuckle and increasing depth of mulching-head treatment. Additionally, increasing mulching-head intensities were correlated with increased herbaceous layer diversity and conservation value as represented by Floristic Quality Index. Mulching-head treatments are a promising tool in controlling heavy invasions of non-native shrubs.(5929508), Travis J. Beckett. "Selection and Characterization of Previously Plant-Variety-Protected Commercial Maize Inbreds." Thesis, 2019.
Знайти повний текст джерела(9838208), David Sturgess. "Using genetic and evolutionary algorithms to solve boundary control problems in soil-water-plant interaction." Thesis, 2002. https://figshare.com/articles/thesis/Using_genetic_and_evolutionary_algorithms_to_solve_boundary_control_problems_in_soil-water-plant_interaction/13429310.
Повний текст джерела(5930189), Javier Ribera Prat. "Image-based Plant Phenotyping Using Machine Learning." Thesis, 2019.
Знайти повний текст джерелаThis thesis also examines the use of crowdsourcing information in video analytics. The large number of cameras deployed for public safety surveillance systems requires intelligent processing capable of automatically analyzing video in real time. We incorporate crowdsourcing in an online basis to improve a crowdflow estimation method. We present various approaches to characterize this uncertainty and to aggregate crowdsourcing results. Our techniques are evaluated using publicly available datasets.
(7870844), Yuhao Chen. "ESTIMATING PLANT PHENOTYPIC TRAITS FROM RGB IMAGERY." Thesis, 2019.
Знайти повний текст джерела(6554648), Ryan D. Calvert. "DIETARY MODULATION OF MYELOID DERIVED SUPPRESSOR CELL BIOLOGY IN PATHOPHYSIOLOGY AND PHYSIOLOGY." Thesis, 2019.
Знайти повний текст джерела(9832871), Abu Sayem. "Experimental study of electrostatic precipitator of a coal based power plant to improve performance by capturing finer particles." Thesis, 2019. https://figshare.com/articles/thesis/Experimental_study_of_electrostatic_precipitator_of_a_coal_based_power_plant_to_improve_performance_by_capturing_finer_particles/13408691.
Повний текст джерела(9795776), Meryl Ferguson. "Life cycle and biology of Sychnocotyle kholo Ferguson, Cribb and Smales, 1998 with a survey of the parasites of Emydura krefftii Gray, 1881 and a revision of the subclass Aspidogastrea." Thesis, 2002. https://figshare.com/articles/thesis/Life_cycle_and_biology_of_Sychnocotyle_kholo_Ferguson_Cribb_and_Smales_1998_with_a_survey_of_the_parasites_of_Emydura_krefftii_Gray_1881_and_a_revision_of_the_subclass_Aspidogastrea/13461005.
Повний текст джерела(5931173), Jessica Merkling. "Development of an Environmental DNA Assay for Eastern Massasauga." Thesis, 2019.
Знайти повний текст джерела(9757040), Lina M. Aboulmouna. "Towards cybernetic modeling of biological processes in mammalian systems—lipid metabolism in the murine macrophage." Thesis, 2020.
Знайти повний текст джерелаRegulation of metabolism in mammalian cells is achieved through a complex interplay between cellular signaling, metabolic reactions, and transcriptional changes. The modeling of metabolic fluxes in a cell requires the knowledge of all these mechanisms, some of which may be unknown. A cybernetic approach provides a framework to model these complex interactions through the implicit accounting of such regulatory mechanisms, assuming a biological “goal”. The goal-oriented control policies of cybernetic models have been used to predict metabolic phenomena ranging from complex substrate uptake patterns and dynamic metabolic flux distributions to the behavior of gene knockout strains. The premise underlying the cybernetic framework is that the regulatory processes affecting metabolism can be mathematically formulated as a cybernetic objective through variables that constrain the network to achieve a specified biological “goal”.
Cybernetic theory builds on the perspective that regulation is organized towards achieving goals relevant to an organism’s survival or displaying a specific phenotype in response to a stimulus. While cybernetic models have been established by prior work carried out in bacterial systems, we show its applicability to more complex biological systems with a predefined goal. We have modeled eicosanoid, a well-characterized set of inflammatory lipids derived from arachidonic acid, metabolism in mouse bone marrow derived macrophage (BMDM) cells stimulated by Kdo2-Lipid A (KLA, a chemical analogue of Lipopolysaccharide found on the surface of bacterial cells) and adenosine triphosphate (ATP, a danger signal released in response to surrounding cell death) using cybernetic control variables. Here, the cybernetic goal is inflammation; the hallmark of inflammation is the expression of cytokines which act as autocrine signals to stimulate a pro-inflammatory response. Tumor necrosis factor (TNF)-α is an exemplary pro-inflammatory marker and can be designated as a cybernetic objective for modeling eicosanoid—prostaglandin (PG) and leukotriene (LK)—metabolism. Transcriptomic and lipidomic data for eicosanoid biosynthesis and conversion were obtained from the LIPID Maps database. We show that the cybernetic model captures the complex regulation of PG metabolism and provides a reliable description of PG formation using the treatment ATP stimulation. We then validated our model by predicting an independent data set, the PG response of KLA primed ATP stimulated BMDM cells.
The process of inflammation is mediated by the production of multiple cytokines, chemokines, and lipid mediators each of which contribute to specific individual objectives. For such complex processes in mammalian systems, a cybernetic objective based on a single protein/component may not be sufficient to capture all the biological processes thereby necessitating the use of multiple objectives. The choice of the objective function has been made by intuitive considerations in this thesis. If objectives are conjectured, an argument can be made for numerous alternatives. Since regulatory effects are estimated from unregulated kinetics, one encounters the risk of multiplicity in this regard giving rise to multiple models. The best model is of course that which is able to predict a comprehensive set of perturbations. Here, we have extended our above model to also capture the dynamics of LKs. We have used migration as a biological goal for LK using the chemoattractant CCL2 as a key representative molecule describing cell activation leading to an inflammatory response where a goal composed of multiple cybernetic objectives is warranted. Alternative model objectives included relating both branches of the eicosanoid metabolic network to the inflammatory cytokine TNF-α, as well as the simple maximization of all metabolic products such that each equally contributes to the inflammatory system outcome. We were again able to show that all three cybernetic objectives describing the LK and PG branches for eicosanoid metabolism capture the complex regulation and provide a reliable description of eicosanoid formation. We performed simulated drug and gene perturbation analyses on the system to identify differences between the models and propose additional experiments to select the best cybernetic model.
The advantage to using cybernetic modeling is in its ability to capture system behavior without the same level of detail required for these interactions as standard kinetic modeling. Given the complexity of mammalian systems, the cybernetic goal for mammalian cells may not be based solely on survival or growth but on specific context dependent cellular responses. In this thesis, we have laid the groundwork for the application of cybernetic modeling in complex mammalian systems through a specific example case of eicosanoid metabolism in BMDM cells, illustrated the case for multiple objectives, and highlighted the extensibility of the cybernetic framework to other complex biological systems.
(8815928), Samantha Jurecki. "APPLICATION AND VALIDATION OF THE EDNA-METABARCODED MIFISH/MITOFISH PIPELINE FOR ASSESSMENT OF NATIVE AND NON-NATIVE FISH COMMUNITIES OF LAKE MICHIGAN." Thesis, 2020.
Знайти повний текст джерела(6848951), Matthew C. Pharris. "Quantitative Models of Calcium-Dependent Protein Signaling in Neuronal Dendritic Spines." Thesis, 2019.
Знайти повний текст джерелаBiochemical signaling at the connections between neurons, called synapses, regulates dynamic shifts in a synapse’s size and connective strength. Called synaptic plasticity, these shifts are initiated by calcium ion (Ca2+) flux into message-receiving structures called dendritic spines. Within dendritic spines, Ca2+ binds sensor proteins such as calmodulin (CaM). Importantly, Ca2+/CaM may bind and activate a wide variety of proteins, which subsequently facilitate signaling pathways regulating the dendritic spine’s size and connective strength.
In this thesis, I use computational models to characterize molecular mechanisms regulating Ca2+-dependent protein signaling within the dendritic spine. Specifically, I explore how Ca2+/CaM differentially activates binding partners and how these binding partners transduce signals downstream. For this, I present deterministic models of Ca2+, CaM, and CaM-dependent proteins, and in analyzing model output I demonstrate in-part that competition for CaM-binding alone may be sufficient to set the Ca2+ frequency-dependence of protein activation. Subsequently, I adapt my deterministic models into particle-based, spatial-stochastic frameworks to quantify how spatial effects influence model output, showing evidence that spatial gradients of Ca2+/CaM may set spatial gradients of activated proteins downstream. Additionally, I incorporate into my models the most detailed model to-date of Ca2+/CaM-dependent protein kinase II (CaMKII), a multi-subunit protein essential to synaptic plasticity. With this detailed model of CaMKII, my analysis suggests that the many subunits of CaMKII provide avidity effects that significantly increase the protein’s effective affinity for binding partners, particularly Ca2+/CaM. Altogether, this thesis provides a detailed analysis of Ca2+-dependent signaling within dendritic spines, characterizing molecular mechanisms that may be useful for the development of novel therapeutics for patients of neurological disorders.