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Exploring Flavonoid Glycosylation in Kudzu (Pueraria lobata)

The isoflavones in kudzu roots, especially the C-glycosylated isoflavone puerarin, have been linked to many health benefits. Puerarin contains a carbon-carbon glycosidic bond that can withstand hydrolysis. The C-glycosylation reaction in the biosynthesis of puerarin has not been thoroughly investigated, with conflicting reports suggesting that it could take place on daidzein, isoliquiritigenin, or 2,7,4ʹ-trihydroxyisoflavanone. Kudzu species were identified for use in comparative transcriptomics. A non-puerarin producing kudzu was identified as Pueraria phaseoloides and a puerarin producing kudzu was identified as Pueraria montana lobata. Through the use of the plant secondary product glycosyltransferase (PSPG) motif, glycosyltransferases (UGTs) were identified from the transcriptomes. The UGTs that had higher digital expression in P. m. lobata were examined further using additional tools to home in on the UGT that could be responsible for puerarin biosynthesis. One of the UGTs identified, UGT71T5, had previously been characterized from kudzu as a C-glycosyltransferase involved in puerarin biosynthesis through in vitro enzyme activity (with daidzein) and a gain of function approach in soybean hairy roots. Previous studies have not supported the end-product of a pathway such as daidzein as the target for C-glycosylation, and no genetic analysis of UGT function had been conducted in kudzu. The activity of …
Date: August 2021
Creator: Adolfo, Laci Michelle
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Analysis of Multipartite Bacterial Genomes Using Alignment-Free and Alignment-Based Pipelines

In this work, we have performed comparative evolutionary analysis, functional genomics analysis, and machine learning analysis to identify the molecular factors that discriminate between multipartite and unipartite bacteria, with the goal to decipher taxon-specific factors and those that are prevalent across the taxa underlying the these traits. We assessed the roles of evolutionary mechanisms, namely, horizontal gene transfer and gene gain, in driving the divergence of bacteria with single and multiple chromosomes. In addition, we performed functional genomic analysis to garner support for our findings from comparative evolutionary analysis. We found genes such as those encoding conserved hypothetical protein DR_A0179 and hypothetical protein DR_A0109 in Deinococcus radiodurans R1, and Putative phage phi-C31 gp36 major capsid-like protein and hypothetical protein RSP_3729 in Rhodobacter sphaeroides 2.4.1, which are located on accessory chromosomes in both bacteria and were not found in the inferred ancestral sequences, and on the primary chromosomes, as well as were not found in their closest relatives with single chromosome within the same clade. These genes emphasize the important potential roles of the secondary chromosomes in helping multipartite bacteria to adapt to specialized environments or conditions. In addition, we applied machine learning algorithms to predict multipartite genomes based on gene …
Date: August 2021
Creator: Almalki, Fatemah
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Quantifying the Effects of Single Nucleotide Changes in the TATA Box of the Cauliflower Mosaic Virus 35S Promoter on Gene Expression in Arabidopsis thaliana

Synthetic biology is a rapidly growing field that aims to treat cellular biological networks in an analogous way to electrical circuits. However, the field of plant synthetic biology has not grown at the same pace as bacterial and yeast synthetic biology, leaving a dearth of characterized tools for the community. Due to the need for tools for the synthetic plant biologist, I have endeavored to create a library of well-characterized TATA box variants in the cauliflower mosaic virus (CaMV) 35S promoter using the standardized assembly method Golden Braid 2.0. I introduced single nucleotide changes in the TATA box of the CaMV 35S promoter, a genetic part widely used in plant gene expression studies and agricultural biotechnology. Using a dual-luciferase reporter system, I quantified the transcriptional strength of the altered TATA box sequences and compared to the wild-type sequence, both in transient protoplast assays and stable transgenic Arabidopsis thaliana plants. The library of TATA-box modified CaMV 35S promoters with varying transcriptional strengths created here can provide the plant synthetic biology community with a series of modular Golden Braid-adapted genetic parts that can be used dependably and reproducibly by researchers to fine-tune gene expression levels in complex, yet predictable, synthetic genetic circuits.
Date: December 2021
Creator: Amack, Stephanie Carolina
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Probabilistic Modeling for Whole Metagenome Profiling

To address the shortcomings in existing Markov model implementations in handling large amount of metagenomic data with comparable or better accuracy in classification, we developed a new algorithm based on pseudo-count supplemented standard Markov model (SMM), which leverages the power of higher order models to more robustly classify reads at different taxonomic levels. Assessment on simulated metagenomic datasets demonstrated that overall SMM was more accurate in classifying reads to their respective taxa at all ranks compared to the interpolated methods. Higher order SMMs (9th order or greater) also outperformed BLAST alignments in assigning taxonomic labels to metagenomic reads at different taxonomic ranks (genus and higher) on tests that masked the read originating species (genome models) in the database. Similar results were obtained by masking at other taxonomic ranks in order to simulate the plausible scenarios of non-representation of the source of a read at different taxonomic levels in the genome database. The performance gap became more pronounced with higher taxonomic levels. To eliminate contaminations in datasets and to further improve our alignment-free approach, we developed a new framework based on a genome segmentation and clustering algorithm. This framework allowed removal of adapter sequences and contaminant DNA, as well as generation …
Date: May 2021
Creator: Burks, David
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Benefits of Probiotics on Mortality, Growth Performance, Physiological Condition and Gut Histomophology of Juvenile Red Drum (Sciaenops ocellatus)

Results from the present study found for the first time that the use of bacterial strains of Lactobacillus acidophilus, Lactobacillus casei, Bifidobacterium thermophilum, and Enterococcus faecium from the commercial product PrimaLac® had the potential to act as a possible probiotic for juvenile red drum. The addition of PrimaLac® probiotics [whether as a water-soluble probiotic (WSP) or in a probiotic enhanced starter feed (PESF)] reduced mortality (%M), enhanced growth rates (MW, LT, SGR, and DGR), improved feed conversion efficiencies (FCEs), and physical condition factors in the juvenile red drum. Improvement was quantified using external morphological condition indices (MCIs) and blood physiological condition indices (PCIs). Results showed a strong positive relationship between MCIs and PCIs, which suggested that probiotics treated fish were in better health (lower MCIs) with lower fasting blood glucose and lactate levels than control fish. Addition of probiotics also resulted in improved water quality (lower nitrate, nitrite, and ammonia) in the treatment tanks compared to controls. Application of PrimaLac® probiotics on the morphology and histology of three different regions of the intestine (proximal, mid-and distal) improved intestinal length (Li), mass (Mi), and digesta mass (Md). In 5μm histological sections examined for differences among treatments (probiotics vs. controls), five variables …
Date: May 2021
Creator: Busby, Wren Adell
Object Type: Thesis or Dissertation
System: The UNT Digital Library
CO2 Transport and Acid-Base Status during Fluctuations in Metabolic Status in Reptiles (open access)

CO2 Transport and Acid-Base Status during Fluctuations in Metabolic Status in Reptiles

Reptiles can often experience perturbations that greatly influence their metabolic status (e.g., temperature, exercise, digestion, and ontogeny). The most common cause of fluctuations in metabolic status in post-embryonic reptiles is arguably digestion and physical activity (which will be further referred to as exercise). The objective of this thesis is to determine the mechanisms involved in CO2 transport during digestion, determine the mechanisms that allow for the maintenance of acid-base homeostasis during digestion, and observing the effect of an understudied form of exercise in semi-aquatic reptiles on the regulation of metabolic acidosis and base deficit. This dissertation provided evidence for potentially novel and under investigated mechanisms for acid-base homeostasis (e.g., small intestine and tissue buffering capacity; Chapters 3 & 4), while also debunking a proposed hypothesis for the function of an anatomical feature that still remains a mystery to comparative physiologist (Chapter 2). This thesis is far from systematic and exhaustive in its approach, however, the work accomplished in this dissertation has become the foundation for multiple distinct paths for ecologically relevant investigations of the regulation of metabolic acidosis/alkalosis in reptiles.
Date: December 2021
Creator: Conner, Justin Lawrence
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Effect of Phosphorus Starvation on Metabolism and Spatial Distribution of Phosphatidylcholine in Medicago truncatula Wild-Type and PDIL3 Genotypes

Symbiotic nitrogen (N) fixation (SNF) occurs in specialized organs called nodules after successful interactions between legume hosts and rhizobia. Within nodule cells, N-fixing rhizobia are surrounded by plant-derived symbiosome membranes, through which the exchange of nutrients and ammonium occurs between bacteria and the host legume. Phosphorus (P) is an essential macronutrient, and N2-fixing legumes have a higher requirement for P than legumes grown on mineral N. First, I investigated the impact of P deprivation on wild-type Medicago truncatula plants. My observations that plants had impaired SNF activity, reduced growth, and accumulated less phosphate in P-deficient tissues (leaves, roots and nodules) is consistent with those of similar previous studies. Galactolipids decreased with increase in phospholipids in all P-starved organs. Matrix-assisted laser desorption/ionization–mass spectrometry imaging (MALDI-MSI) of phosphatidylcholine (PC) species in nodules showed that under low P environments distributions of some PC species changed, indicating that membrane lipid remodeling during P stress is not uniform across the nodule. Secondly, a metabolomics study was carried out to test the alterations in the metabolic profile of the nodules in P-stress. GC-MS based untargeted metabolomics showed increased levels of amino acids and sugars and decline in amounts of organic acids in P deprived nodules. Subsequently, …
Date: August 2021
Creator: Dokwal, Dhiraj
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Form and Function of the Vertebrate and Invertebrate Blood-Brain Barriers (open access)

Form and Function of the Vertebrate and Invertebrate Blood-Brain Barriers

Article reviewing blood-brain barriers (BBBs) in their various forms in both invertebrates and vertebrates, with an emphasis on the function, evolution, and conditional relevance of popular animal models such as the fruit fly and the zebrafish to mammalian BBB research.
Date: November 9, 2021
Creator: Dunton, Alicia D.; Göpel, Torben; Ho, Dao H. & Burggren, Warren W.
Object Type: Article
System: The UNT Digital Library
Re-engineering Plant Phenylpropanoid Metabolism With the Aid of Synthetic Biosensors (open access)

Re-engineering Plant Phenylpropanoid Metabolism With the Aid of Synthetic Biosensors

Article that provides a brief overview of current research on synthetic biology and metabolic engineering approaches to control phenylpropanoid synthesis and phenylpropanoid-related biosensors, advocating for the use of biosensors and genetic circuits as a step forward in plant synthetic biology to develop autonomously-controlled phenylpropanoid-producing plant biofactories.
Date: September 16, 2021
Creator: Ferreira, Savio S. & Antunes, Mauricio S.
Object Type: Article
System: The UNT Digital Library
Sociality in Harris's Hawks Revisited: Patterns of Reproductive Output and Delayed Dispersal (open access)

Sociality in Harris's Hawks Revisited: Patterns of Reproductive Output and Delayed Dispersal

In the lower Rio Grande Valley of south Texas, more than half the nesting groups of Harris's hawks (Parabuteo unicinctus) include at least one auxiliary group member in addition to a breeding pair. To provide further insight into cooperatively breeding raptors, I evaluated sociality in Harris's hawks through the dual benefits framework. I explored the formation, structure, and stability of cooperative group formation across a spatially variable study area, which includes high levels of urbanization and development as well as remote, undisturbed native habitats with low anthropogenic impact. I used color banding, regular censuses of active territories, and a microsatellite relatedness analysis to examine patterns of sociality, including delayed dispersal, the effect of auxiliary group members on reproductive output, parentage of broods, and the relatedness of auxiliaries compared to the nestlings in their territories. I confirmed cooperative polygamy with genetic techniques for the first time in Harris's hawks and found 58% of juvenile hawks delayed dispersal for at least 6 mo. Using the dual benefits framework, I found social associations that formed through delayed dispersal followed predictions for resource-defense benefits, but sociality among mature non-related hawks more closely followed predictions associated with collective action benefits, specifically reproductive output was significantly …
Date: August 2021
Creator: Gibbons, Andrea L
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Studies on the Fibrinolytic Pathway in Zebrafish

Fibrinolysis pathway is an important mechanism for dissolution of fibrin clot by the action of plasmin which is formed from plasminogen, a zymogen via the action of plasminogen activators, i.e. tissue plasminogen activator and urinary plasminogen activator. The regulation of fibrinolysis system in vivo is maintained by plasminogen activators and natural inhibitors i.e. α2-antiplasmin, α2-macroglobulin, Thrombin-activatable fibrinolysis inhibitor (TAFI) and plasminogen activator inhibitor 1 and 2 (PAI-1and PAI-2). There are several fibrinolytic assays developed for human plasma but there are no reports describing fibrinolytic assay using zebrafish plasma. In this study, a fibrinolytic assay via using small amount of zebrafish plasma was developed. This assay was performed under different conditions; one by the addition of exogenous tissue plasminogen activator alone to the pooled zebrafish plasma along with calcium chloride and thromboplastin, second Dade ACTIN was used instead of tissue plasminogen activator and third Dade ACTIN along with thromboplastin was used. Epsilon amino caproic acid (EACA), a synthetic antifibrinolytic agent was used at different concentrations to inhibit fibrinolysis successfully. Similar experiments were performed on human plasma as well to check the applicability of the assay to humans and positive results were obtained. Furthermore, knockdown of tissue plasminogen activator and plasminogen genes …
Date: August 2021
Creator: Gill, Jaspreet Kaur
Object Type: Thesis or Dissertation
System: The UNT Digital Library

A Test of the Female Mimicry Hypothesis in Painted Buntings (Passerina ciris)

While female mimicry and lower status signaling hypotheses of delayed plumage maturation have received much discussion in the literature, the experimental tests of these hypotheses have been infrequent. Those experimental tests often use a simulated intruder method with artificial model intruders rather than using live conspecific birds as intruders. Subadult male painted buntings (Passerina ciris) possess delayed plumage maturation where they appear visually identical to adult females during their first potential breeding season, while adult males are strikingly different in plumage coloration. Here I test the behavioral responses in a territorial population of painted buntings that exhibits extreme delayed plumage maturation using a simulated territorial intrusion experiment to measure territorial male behavioral response when presented with live caged intruders of both subadult and adult males. Territorial adult males were significantly more likely to initiate an attack and continue to attack caged adult male intruders than compared to caged subadult male intruders. This result supports both the female mimicry and status signaling hypotheses, and does not support the cryptic hypothesis. Additionally, in anecdotal observations, territorial males occasionally performed mating display behaviors to caged subadult male intruders. These results further suggest that territorial male painted buntings may identify subadult males as potential …
Date: May 2021
Creator: Gurley, Christine E
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Biomonitoring at Dallas-Fort Worth International Airport: Relating Watershed Land Use with Aquatic Life Use

The Dallas-Fort Worth International (DFW) Airport is located in a densely urbanized area with one of the fastest-growing populations in the U.S.A. The airport property includes a large tract of "protected" riparian forest that is unique to the urban surroundings. This dissertation explores variables that influence the benthic macroinvertebrate community structure found in urbanized prairie streams that were initially assessed by the University of North Texas (UNT) Benthic Ecology Lab during four, non-consecutive biomonitoring studies (2004, 2005, 2008, and 2014) funded by the DFW Airport. Additionally, land use analysis was performed using 5-meter resolution satellite imagery and eCognition to characterize the imperviousness of the study area watersheds at multiple scales. Overall, flow conditions and imperviousness at the watershed scale explained the most variability in the benthic stream community. Chironomidae taxa made up 20-50% of stream communities and outperformed all other taxa groups in discriminating between sites of similar flows and urban impairments. This finding highlights the need for genus level identifications of the chironomid family, especially as the dominant taxa in urban prairie streams. Over the course of these biomonitoring survey events, normal flow conditions and flows associated with supra-seasonal drought were experienced. Prevailing drought conditions of 2014 did not …
Date: August 2021
Creator: Harlow, Megann Mae Lewis
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Multiple Dimensions of Fish Functional Traits, Trait Relationships, and Associations with Community Structure and Dynamics

Trait-based approaches are useful in ecological research because of their potential ability to predict species responses from patterns present in the community and to infer mechanisms driving community assembly. Current approaches for fishes are lacking traits across all five fundamental niche dimensions (i.e. habitat, life history, trophic, metabolic and defense). This study quantified a broad range of fish functional traits across all five niche dimensions (commonly used traits and novel traits), quantified intra- and interspecific variation for each trait, tested for relationships among traits within and among niche dimensions, tested for phylogenetic conservatism of traits and assessed trait-environment relationships for a subset of these traits under two different contexts. Approximately one third of the quantified traits exhibited greater intraspecific variation than interspecific variation and were not included in subsequent analyses. There were similarities between phylogeny and trait dendrograms for all traits, and habitat, metabolic and defense traits. The traits identified in chapter 2 were able to explain species responses during different flow periods in two intermittent streams as well as species-specific differences in host microbiome at the onset of drought in one intermittent stream. The novel traits identified in chapter 2 did contribute to our understanding of the community assembly …
Date: December 2021
Creator: Harried, Brittany Lee
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Ecological Responses to Severe Flooding in Coastal Ecosystems: Determining the Vegetation Response to Hurricane Harvey within a Texas Coast Salt Marsh (open access)

Ecological Responses to Severe Flooding in Coastal Ecosystems: Determining the Vegetation Response to Hurricane Harvey within a Texas Coast Salt Marsh

Vegetative health was measured both before and after Hurricane Harvey using remotely sensed vegetation indices on the coastal marshland surrounding Galveston Island's West Bay. Data were recorded on a monthly basis following the hurricane from September of 2005 until September of 2019 in order to document the vegetation response to this significant disturbance event. Both initial impact and recovery were found to be dependent on a variety of factors, including elevation zone, spatial proximity to the bay, the season during which recovery took place, as well as the amount of time since the hurricane. Slope was also tested as a potential variable using a LiDAR-derived slope raster, and while unable to significantly explain variations in vegetative health immediately following the hurricane, it was able to explain some degree of variability among spatially close data points. Among environmental factors, elevation zone appeared to be the most key in determining the degree of vegetation impact, suggesting that the different plant assemblages that make up different portions of the marsh react differently to the severe flooding that took place during Harvey.
Date: August 2021
Creator: Hudman, Kenneth Russell
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Crucial Development: Criticality Is Important to Cell-to-Cell Communication and Information Transfer in Living Systems (open access)

Crucial Development: Criticality Is Important to Cell-to-Cell Communication and Information Transfer in Living Systems

This article is the fourth paper of the Special Issue Memory and Criticality. It bridges the the theoretical debate on the role of memory and criticality discussed in the three earlier manuscripts, with a review of key concepts in biology and focus on cell-to-cell communication in organismal development. The authors suggest that in conjunction with morphogenetic gradients, there exist gradients of information transfer creating cybernetic loops of stability and disorder, setting the stage for adaptive capability. Criticality, therefore, appears to be an important factor in the transmission, transfer and coding of information for complex adaptive system development.
Date: August 31, 2021
Creator: Hunt von Herbing, Ione; Tonello, Lucio; Benfatto, Maurizio; Pease, April & Grigolini, Paolo
Object Type: Article
System: The UNT Digital Library

Studies on Intrinsic Coagulation Pathway of Zebrafish

In the past couple of decades, the zebrafish has been widely used to study hemostatic disorders. In this study, we generated a CRISPR/Cas9 mediated zebrafish mutant that contains a 55-nucleotide insertion in exon 29 of the von Willebrand factor (vwf) gene. The mutants had impaired ristocetin-mediated agglutination of whole blood, prolonged PTT and more bleeding in the lateral incision compared to wild-type fish. The bleeding phenotype observed here is similar to the phenotype observed in vwf knockout mice and patients with von Willebrand disease (VWD). The mutant model developed here can thus be used for exploring the role of Vwf in angiogenesis and for developing gene therapy. The deficiency of VWF causes VWD and the etiology remains unknown in 30% of Type 1 VWD cases. Previous studies have identified that the ABO blood group and ST3GAL4 (glycosyltransferases) are involved in the regulation of VWF levels. Since VWF is heavily glycosylated, we hypothesized that other glycosyltransferases may also be involved in regulating VWF. We performed a knockdown screen of 234 glycosyltransferase genes and identified 14 genes that altered Vwf levels. The sequencing of these genes in Type 1 VWD patients could help identify novel mutations to decipher the molecular basis for …
Date: August 2021
Creator: Iyer, Neha
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Breeding Ecology and Migratory Connectivity of Passerines in the World's Southernmost Forests (open access)

Breeding Ecology and Migratory Connectivity of Passerines in the World's Southernmost Forests

In the extensive and remote sub-Antarctic forests of South America, birds are the dominant terrestrial vertebrates. Despite considerable efforts to understand the ecology of birds breeding in these forests, our current knowledge for many species is still incomplete. During three breeding seasons (2014 – 2017), I studied the breeding ecology of the five most abundant open-cup forest-dwelling passerines in the sub-Antarctic forest of Navarino Island, Chile (55°04′S, 67°40′W). There were differences in some of the breeding strategies used by birds breeding on Navarino Island versus conspecific populations breeding at lower latitudes. Milvago chimango was the main nest predator of open-cup nesting forest passerines, and the main cause of nest failure. In addition, I found that species built their nests in sites with higher density and taller understory; however, these two factors decreased their nest survival. This mismatch could be due to a change in depredation risk on Navarino Island, and thus, passerines breeding there may be in an ecological trap. In addition, using light-level geolocators, I determined that the migratory connectivity of Elaenia albiceps is weak as a result of the large spatial spread of individuals on the wintering ground, and that the distances among individuals on the breeding grounds …
Date: May 2021
Creator: Jara Millar, Rocio Fernanda
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Dietary Polyphenol and Methylsulfonylmethane Supplementation Improves Immune, DAMP Signaling, and Inflammatory Responses During Recovery From All-Out Running Efforts (open access)

Dietary Polyphenol and Methylsulfonylmethane Supplementation Improves Immune, DAMP Signaling, and Inflammatory Responses During Recovery From All-Out Running Efforts

This article presents a study with the purpose to determine the effect of dietary supplementation with optimized curcumin, pomegranate ellagitannins, and MSM (R + MSM) on immune-associated mRNA during early recovery (i.e., up to 8 h post-exercise) following all-out running efforts (5-km, 10-km, and 21.1-km). The results demonstrate that supplementation with a combination of optimized curcumin, pomegranate ellagitannins, and methylsulfonylmethane resulted in changes that may improve biological recovery from all-out running efforts.
Date: August 31, 2021
Creator: McFarlin, Brian K.; Hill, David W.; Vingren, Jakob L.; Curtis, John H. & Tanner, Elizabeth A.
Object Type: Article
System: The UNT Digital Library

Influence of Hypoxia on Acute Lead Toxicity and Calcium Homeostasis in Early Life Stage Zebrafish (Danio rerio)

The purpose of this study was to investigate the effects of Pb and hypoxia co-exposure on Pb toxicity and Ca homeostasis in early life stage (ELS) zebrafish (Danio rerio). Previous evidence indicates that exposure of ELS zebrafish to hypoxia (~20% air saturation) reduces Ca uptake, likely through down-regulation of the apical epithelial Ca channel (ECaC). Considering that Pb and Ca are known antagonists and compete for uptake pathways, it was hypothesized that co-exposure of Pb with hypoxia would decrease Pb toxicity by reducing Pb uptake (likely mediated through a reduced number of ECaCs). However, it was shown that at 96 hpf, whole body accumulation of both Pb and Ca was lower at 40% air saturation compared to 100% and 20% air saturation. This result closely aligned with the 96h LC50 results which showed the highest mortality of zebrafish at 40% compared to the other air saturation levels. This suggests that toxicity is likely the result of exacerbated hypocalcemia at 40% air saturation due to both Pb competition for Ca binding to Ca uptake channels/transporters, such as ECaC, and potentially reduced expression of such channels/transporters in response to this level of hypoxia. Overall, it appears that ELS zebrafish respond differentially to …
Date: December 2021
Creator: Moghimi, Mehrnaz
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Ozone Pollution Monitoring and Population Vulnerability in Dallas-Ft. Worth: A Decision Support Approach

In urban environments, ozone air pollution, poses significant risks to respiratory health. Fixed site monitoring is the primary method of measuring ozone concentrations for health advisories and pollutant reduction, but the spatial scale may not reflect the current population distribution or its future growth. Moreover, formal methods for the placement of ozone monitoring sites within populations potentially omit important spatial criteria, producing monitoring locations that could unintentionally underestimate the exposure burden. Although air pollution affects all people, the combination of underlying health, socioeconomic and demographic factors exacerbate the impact for socially vulnerable population groups. A need exists for assessing the spatial representativeness and data gaps of existing pollution sensor networks and to evaluate future placement strategies of additional sensors. This research also seeks to understand how air pollution monitor placement strategies may neglect social vulnerabilities and therefore, potentially underestimate exposure burdens in vulnerable populations.
Date: August 2021
Creator: Northeim, Kari M.
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Multi-Omics Based Investigation of Distinct Early Oxidative Stress Responses of Saccharomyces cerevisiae to Various Oxidants

The early signaling mechanism(s) that control oxidant perception and signal transduction leading to activation of the antioxidant defense response and survival mechanisms tailored toward specific oxidative insult remains unknown. Here, we identified early changes in metabolome and proteome of S. cerevisiae in response to hydrogen peroxide, menadione, cumene hydroperoxide, and diamide. Firstly, global untargeted LC–MS/MS analysis allowed us to identify 196 proteins in response to hydrogen peroxide, 569 proteins in response to cumene hydroperoxide, 369 proteins in response to menadione and 207 proteins in response to diamide that were significantly regulated at 3 min after exposure. We revealed that each oxidant triggered unique signaling mechanisms associated with survival and repair mechanisms as early as 3 minutes of post treatment with a set of proteins that uniquely responded to the particular oxidant. In addition, our comprehensive pathway analysis revealed signaling pathways and the molecular players that are regulated globally by all oxidants at early time points namely Ran, mTOR, Rho, and eIF2. Additionally, we analyzed metabolic response using targeted GC-MS/MS that allowed us to identity 35 metabolites that were consistently detected in all samples at 3 min of exposure. These metabolites showed distinct response to the four oxidants in carbohydrate metabolism, …
Date: May 2021
Creator: Pandey, Prajita
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Investigating the Effects of Inhaled Diesel Exhaust Particles on Gut Microbiome, Intestinal Integrity, Systemic Inflammation, and Biomarkers of Cardiovascular Disease in Wildtype Mice

We investigated the hypothesis that exposure to inhaled diesel exhaust PM can alter the gut microbiome and intestinal integrity, thereby promoting systemic inflammatory response and early CVD risk, which are exacerbated by HF diet. Furthermore, we investigated whether the observed exposure and diet-mediated outcomes could be mitigated through probiotic treatment. We performed an exposure study on C57Bl/6 male mice, placed on either a low fat (LF) diet or a high-fat (HF) diet, and exposed via oropharyngeal aspiration to 35 μg diesel exhaust particles (DEP) suspended in 35 μl of sterile saline or sterile saline controls (CON) twice a week for four weeks. A subset of mice on HF diet were dosed with 0.3 g/day (PRO, ~7.5x108 CFU/day) of probiotic Ecologic® Barrier 849 (Winclove Probiotics) in drinking water during the course of the study. For our first aim, we investigated the alterations in the gut microbiome, measured circulating cytokines and lipopolysaccharide (LPS), and measured CVD biomarkers in the heart. Our results revealed that exposure to inhaled DEP results in gut dysbiosis characterized by expansion of the phyla Verrucomicrobia and Proteobacteria and reduction in Actinobacteria, which was exacerbated by HF diet. Probiotics mitigated the DEP-mediated expansion of Proteobacteria and re-established Actinobacteria in …
Date: December 2021
Creator: Phillippi, Danielle T.
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Manipulation of Lipid Droplet Biogenesis for Enhanced Lipid Storage in Arabidopsis thaliana and Nicotiana benthamiana

In this study, I examined the use of mouse (Mus musculus) Fat Specific Protein 27 (FSP27) ectopically expressed in Arabidopsis thaliana and Nicotiana benthamiana as a means to increase lipid droplet (LD) presence in plant tissues. In mammalian cells, this protein induces cytoplasmic LD clustering and fusion and helps prevent breakdown of LDs contributing to the large, single LD that dominates adipocytes. When expressed in Arabidopsis thaliana and Nicotiana benthamiana, FSP27 retained its functionality and supported the accumulation of numerous and large cytoplasmic LDs, although it failed to produce the large, single LD that typifies adipose cells. FSP27 has no obvious homologs in plants, but a search for possible distant homologs in Arabidopsis returned a Tudor/PWWP/MBT protein coded for by the gene AT1G80810 which for the purposes of this study, we have called LIPID REGULATORY TUDOR DOMAIN CONTAINING GENE 1 (LRT1). As a possible homolog of FSP27, LRT1 was expected to have a positive regulatory effect on LDs in cells. Instead, a negative regulatory effect was observed in which disruption of the gene induced an accumulation of cytoplasmic LDs in non-seed tissue. A study of lrt1 mutants demonstrated that disruption this gene is the causal factor of the cytoplasmic LD …
Date: December 2021
Creator: Price, Ann Marie
Object Type: Thesis or Dissertation
System: The UNT Digital Library