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Maturation of Endothermic Capacity within the Avian Developmental Spectrum: A Characterization of Thermoregulatory Metamorphosis

Description: An avian embryo is ectothermic, with body temperature determined by environmental temperature. Upon hatching, the neonate begins a conversion so that endothermic capacity becomes feasible and body temperature becomes independent of environment. Whole animal metabolic rate and ventilation response, cardiovascular development, and maturation of muscle mitochondrial flux were the focus of this dissertation because of the direct role in shivering thermogenesis. Precocial ducks and altricial Double-crested Cormorants exhibit increasing hematocrit and disproportionate increases in fractional heart mass resulting in greater oxygen delivery capacity and increased capacity of muscles to utilize oxygen compared with ectothermic American Alligator and Common Snapping turtles. By selecting for faster growth and higher meat yield in the domestic chicken, differences in whole-animal, tissue, cellular, and regulatory responses are evident between broiler and layer type birds. In the altricial red-winged blackbird, despite appearance of a whole animal endothermic response sometime after 7 dph, capacity of skeletal muscles involved in shivering thermogenesis peaks prior to that time. Thus, full development of endothermy is delayed in this species, allowing the altricial nestling to allocate energy towards growth rather than metabolic maintenance. Hypothyroidism in neonate red-winged blackbirds results in delayed maturation of the cardiovascular system and mitochondrial oxidative capacity of skeletal muscle. Such deficiencies were quickly recovered once the animals returned to a normothyroid state, apparently at the cost of increasing body mass. Insights into onset of thermoregulation provide a more thorough understanding of metabolic and physical transitions a hatchling bird must undergo to reach the adult endothermic phenotype. Endothermic capacity will continue to be at the forefront of physiological research because of the significance of changes between the energetic relations of an animal that must occur with its environment.
Date: August 2016
Creator: Sirsat, Sarah Goy
Partner: UNT Libraries

Glucose and Altered Ceramide Biosynthesis Impact the Transcriptome and the Lipidome of Caenorhabditis elegans

Description: The worldwide rise of diabetes and obesity has spurred research investigating the molecular mechanisms that mediate the deleterious effects associated with these diseases. Individuals with diabetes and/or obesity are at increased risk from a variety of health consequences, including heart attack, stroke and peripheral vascular disease; all of these complications have oxygen deprivation as the central component of their pathology. The nematode Caenorhabditis elegans has been established as a model system for understanding the genetic and molecular regulation of oxygen deprivation response, and in recent years methods have been developed to study the effects of excess glucose and altered lipid homeostasis. Using C. elegans, I investigated transcriptomic profiles of wild-type and hyl-2(tm2031) ( a ceramide biosynthesis mutant) animals fed a standard or a glucose supplemented diet. I then completed a pilot RNAi screen of differentially regulated genes and found that genes involved in the endobiotic detoxification pathway (ugt-63 and cyp-25A1) modulate anoxia response. I then used a lipidomic approach to determine whether glucose feeding or mutations in the ceramide biosynthesis pathway or the insulin-like signaling pathway impact lipid profiles. I found that gluocose alters the lipid profile of daf-2(e1370) (an insulin-like receptor mutant) animals. These studies indicate that a transcriptomic approach can be used to discover novel pathways involved in oxygen deprivation response and further validate C. elegans as a model for understanding diabetes and obesity.
Date: August 2016
Creator: Ladage, Mary Lee
Partner: UNT Libraries

Cardiovascular Fetal Programming in Quail (Colinus virginianus), An Avian Comparative Model

Description: The consequences of early embryonic insults and how they affect subsequent life reflects the emerging concept of "fetal programming". The aim of this project is to study the effects of embryonic insults as they subsequently manifest themselves in adults, with emphasis on the heart and vasculature. My experiments establish that fetal programming operates on the bobwhite quail inducing similar changes as those observed in mammalians and other birds. The quail's fast development provides reliable data in a short period of time than other avian models (e.g. domestic chicken). Data on quail showed a correlation between egg mass and hatchling mass; where small eggs produce small hatchlings but a high mortality made it impractical as a stressor for this study. Hypoxia was used as a stressor during embryonic incubation, where it induced a low hatching weight in quail that was not observable in adult birds. Morphological measurements demonstrated an increased ventricular collagen content and reduced ventricular lumen in birds in adults incubated in hypoxia consistent with hypertension. The hematological analyzes showed few differences indicating organ remodeling instead of hematopoietic compensation. The assessment of vascular reactivity pointed out an impaired endothelium dependent relaxation commonly associated to hypertension in birds and mammals. Fetal programming could be a widespread response to an adverse prenatal environment in endotherms and the resulting data from this work contributes to our understanding of fetal programming in vertebrates and its long term consequences.
Date: December 2016
Creator: Flores Santin, Josele
Partner: UNT Libraries

Maternal Transfer of Dietary Methylmercury and Implications for Embryotoxicity in Fathead Minnows (Pimephales promelas)

Description: Mercury (Hg) is a ubiquitous environmental contaminant, which is capable of global atmospheric transport. As a result, even the most pristine aquatic ecosystems are affected by atmospheric Hg deposition, following which microbial transformation yield organic Hg forms, the most concerning of which is methylmercury (MeHg). Methylmercury is capable of bioaccumulation and biomagnification in food webs, resulting in potentially toxic body burdens due to regular dietary exposure in long-lived organisms at higher trophic levels. It is also a molecular mimic of some endogenous amino acids, providing a route of transfer from mother to offspring via large amino acid transporters. Exposure during neurodevelopment can lead to serious, irreversible neurological dysfunction, associated with a variety of cognitive and motor abnormalities across species. The present studies evaluate the effects of maternally-transferred dietary MeHg, at environmentally relevant concentrations on early life stage fathead minnows (Pimephales promelas). Embryos were collected from adult fatheads exposed to one of three diets with varying concentrations of MeHg for 30 days. Adult reproductive metrics were also monitored over the course of the study, with results indicating no effects on spawning frequency, clutch size, or total egg output. In embryos, Hg concentration was a function of female diet and the duration (number of days) of female exposure. Offspring spawned in tanks administered the low Hg diet displayed altered embryonic movement patterns (hyperactivity), decreased time to hatch, decreased mean larval size, and alterations to several metabolite abundances when compared with controls. Significantly altered metabolites include those associated with cellular energetics, fatty acid metabolism, and polyamine synthesis, indicating current environmental exposure scenarios are sufficient to disrupt important cellular pathways. Dysregulation of the dopaminergic system of embryos is also characterized, and may be a possible mechanism by which hyperactive behaviors are observed in these embryos. Offspring from tanks administered the high Hg diet exhibited ...
Date: December 2016
Creator: Bridges, Kristin
Partner: UNT Libraries

Effects of Brain Brain Injury on Primary Cilia of Glial Cells and Pericytes

Description: Glial cells maintain homeostasis that is essential to neuronal function. Injury to the nervous system leads to the activation and proliferation of glial cells and pericytes, which helps to wall off the damaged region and restore homeostatic conditions. Sonic hedgehog is a mitogen which is implicated in injury-induced proliferation of glial cells and pericytes. The mitogenic effects of sonic hedgehog require primary cilia, but the few reports on glial or pericyte primary cilia do not agree about their abundance and did not address effects of injury on these cilia. Primary cilia are microtubule-based organelles that arise from the centrosome and are retracted before cells divide. Depending on cell type, proteins concentrated in cilia can transduce several mitotic, chemosensory, or mechanosensory stimuli. The present study investigated effects of stab wound injury on the incidence and length of glial and pericyte primary cilia in the area adjacent to the injury core. Astrocytes, polydendrocytes and pericytes were classified by immunohistochemistry based on cell-type markers. In normal adult mice, Arl13b immunoreactive primary cilia were present in a majority of each cell type examined: astrocytes, 98±2%; polydendrocytes, 87±6%; and pericytes, 79±13% (mean ± SEM). Three days post-injury, cilium incidence decreased by 24% in astrocytes (p< 0.008) and 41% in polydendrocytes (p< 0.002), but there was no significant effect in pericytes. Polydendrocytes labeled with the cell cycle marker Ki67 were less likely to have cilia compared to resting, Ki67- polydendrocytes. Considering post-injury rates of proliferation for astrocytes and polydendrocytes, it appears that resorption of cilia due to cell cycle entry may account for much of the loss of cilia in polydendrocytes but was not sufficient to account for the loss of cilia in astrocytes. Under normal conditions, astrocytes rarely divide, and they maintain non-overlapping territories. However, three days after injury, there was a 7-fold increase in ...
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Date: December 2016
Creator: Coronel, Marco Vinicio
Partner: UNT Libraries

Glucose Induces Sensitivity to Oxygen Deprivation and Alters Gene Expression in Caenorhabditis Elegans

Description: An organisms’ diet represents an exogenous influence that often yields colossal effects on long-term health and disease risk. The overconsumption of dietary sugars for example, has contributed to significant increases in obesity and type-2 diabetes; health issues that are costly both economically and in terms of human life. Individuals who are obese or are type-2 diabetic often have compromised oxygen delivery and an increased vulnerability to oxygen-deprivation related complications, such as ischemic strokes, peripheral arterial disease and myocardial infarction. Thus, it is of interest to identify the molecular changes glucose supplementation or hyperglycemia can induce, which ultimately compromise oxygen deprivation responses. By utilizing the Caenorhabditis elegans genetic model system, which is anoxia tolerant, I determined that a glucose-supplemented diet negatively impacts responses to anoxia and that the insulin-like signaling pathway, through fatty acid and ceramide biosynthesis and antioxidant activity, modulates anoxia survival. Additionally, a glucose-supplemented diet induces lipid accumulation. Use of RNA-sequencing analysis to compare gene expression responses in animals fed either a standard or glucose-supplemented diet revealed that glucose impacts the expression of genes involved with multiple cellular processes including lipid and carbohydrate metabolism, stress responses, cell division, and extracellular functions. Several of the genes we identified are homologous to human genes that are differentially regulated in response to metabolic diseases, suggesting that there may be conserved gene expression responses between C. elegans supplemented with glucose and a diabetic and/or obese state observed in humans. These findings support the utility of C. elegans to model specific aspects of the T2D disease process (e.g., glucose-induced sensitivity to oxygen deprivation) and identify potentially novel regulators of common complications seen in hyperglycemic and T2D patients (e.g., macrovascular complications).
Date: August 2015
Creator: Garcia, Anastacia M.
Partner: UNT Libraries

Thresholds and Legacy Effects of Tropical Floodplain Fish Assemblages in Response to Flood Attributes

Description: Natural flow regimes are critical for sustaining biodiversity and river integrity. Floods and droughts form an important component of river systems and control population sizes and species diversity across space and time. Modification of flow regimes, including disruption of the timing, magnitude and duration of flooding, is a global problem, and many new impoundments are planned for large river-floodplain ecosystems in the tropics. Flow modifications may cause dramatic non-linear responses in population sizes and have lasting effects through time, but such topics are poorly investigated over multi-year scales, especially in highly diverse tropical ecosystems. Using a long-term dataset from the Upper Paraná River floodplain, Brazil, I tested for threshold and legacy effects of fish assemblages to flood attributes, such as timing, magnitude, duration, rate of change and variation. Specifically, I hypothesized that long duration, high magnitude floods would elicit threshold responses in long-distance migratory fish species and these responses result in significant legacy effects detectable over multiple years. Consistent positive threshold responses to increasing flood duration and magnitude were detected for many species and not significantly correlated with reproductive guilds. Legacy effects were prevalent (i.e. identified for more than 90% of species) and including flood attributes from previous years increased variance explained in species abundances by 15-20% compared to contemporary flood attributes alone. Contrary to my hypotheses, flood duration did not elicit strong legacy effects and species from the same reproductive guild did not have similar legacy effects models. The prevalence of legacy effects across almost all species in this diverse study system highlights the need to consider such dynamics in other systems. My results provide targets for management and conservation actions, such as environmental flow releases from upstream reservoirs. Environmental flows releases may play a significant role in sustainability of the floodplain and other tropical floodplain ecosystems affected by ...
Date: December 2015
Creator: Hoeinghaus, Ana Paula Ferrari
Partner: UNT Libraries

Phenotypic Morphological Plasticity Induced by Environmental Salt Stress in the Brine Shrimp, Artemia franciscana

Description: Phenotypic plasticity is the ability of an organism to express different phenotypes in response to biotic or abiotic environmental cues. The ability of an organism to make changes during development to adjust to changes in its environment is a key to survival. Sexually reproducing organisms that have short life cycles and that are easy to raise in the laboratory are more conducive for developmental phenotypic plasticity. Considerable research has already been carried out on the brine shrimp, Artemia franciscana, regarding its morphology due to changing salinities. There is, however, little research considering subsequent generations and how there morphology might be affected by parental experiences. This study has examined: 1) the morphological effects of different rearing regimes of different salinity levels, and 2) the epigenetic transgenerational transfer of these morphological traits in A. franciscana. Measurements included rate of growth (as measured by instar), body size, body length, and other morphological traits. A gradual increase to more hyperosmotic conditions during development produced brine shrimp that were larger in size and also more developmentally advanced. Salinity stress experienced by adults had increased the growth rate in the F1 offspring of A. franciscana. Collectively, these data indicate that Artemia franciscana is a tractable model for investigating phenotypic plasticity. These findings have added to the ever-growing field of developmental phenotypic plasticity while also providing more information on the natural history and adaptive abilities of A. franciscana.
Date: December 2015
Creator: Jones, Shaun Gray
Partner: UNT Libraries

A High-fat Meal Alters Post-prandial mRNA Expression of SIRT1, SIRT4, and SIRT6

Description: Sirtuins (SIRT) regulate the transcription of various genes involved in the development of diet-induced obesity and chronic disease; however, it is unknown how they change acutely following a high-fat meal. The purpose of this study was to determine the effect of a high-fat meal (65% kcals/d; 85% fat recommendation), on SIRT1-7 mRNA expression in blood leukocytes at 1, 3, and 5-h post-prandial. Men and women (N=24) reported to the lab following an overnight fast (>12H). Total RNA was isolated and reverse transcribed prior to using a Taqman qPCR technique with 18S rRNA as a normalizer to determine SIRT1-7 mRNA expression. An additional aliquot of serum was used to measure triglycerides. Data was analyzed using a RM ANOVA with P<0.05. Triglycerides (P<0.001; 124%) peaked at 3-h. SIRT 1 (P=0.004; 70%), and SIRT 6 (P=0.017; 53%) decreased expression at 3-h. SIRT4 (P=0.024) peaked at 5H relative to baseline (70%) and 3-h (68%). To our knowledge, this is the first study to report that consumption of a high-fat meal transiently alters SIRT mRNA expression consistent in a pattern that mirrors changes in serum triglycerides. Decrease in expression of SIRT1 and SIRT6 combined with an increased SIRT4 would be consistent with an increase in metabolic disease risk if maintained on a chronic basis.
Date: December 2015
Creator: Best Sampson, Jill Nicole
Partner: UNT Libraries

The Effect of Post-exercise Ethanol Consumption on the Acute Hormonal Response to Heavy Resistance Exercise in Women

Description: The purpose of this study was to examine the hormonal response to acute ethanol ingestion following a bout of heavy resistance exercise in women. Eight resistance trained women completed two identical acute heavy resistance exercise tasks (AHRET). From 10-20 minutes post-AHRET, participants consumed either a grain ethanol or a placebo beverage. Blood was collected before (PRE) and immediately after the AHRET (IP) and then every 20 minutes for five hours. Blood collected after beverage ingestion was pooled into 3 batches (phases: 20-40 minutes, 60-120 minutes, and 140-300 minutes post-exercise) and analyzed for serum total testosterone (TT), free testosterone (FT), insulin-like growth factor-I (IGF-I), human growth hormone (GH), cortisol (COR), and estradiol (E2) concentrations. Circulating concentrations of TT were significantly greater at P20-40 than at PRE, P60-120, and P140-300. Circulating concentrations of FT were significantly greater at P20-40 than at all other times. Circulating concentrations of GH were significantly greater at IP than at PRE, P60-120, and P140-300. Circulating concentrations of COR were significantly greater at P20-40 than at all other times. Additionally, COR concentrations at P140-300 were significantly lower than at all other times. Circulating concentrations of IGF-1 were significantly greater at P20-40 than at P60-120 and P140-300. Circulating concentrations of E2 were significantly greater at P20-40 than at all other times. In summary, the present study demonstrated an acute modulation of the neuroendocrine milieu following a heavy resistance exercise bout in women. Ethanol ingestion appeared to have no significant effect on the characteristics of acute hormonal augmentation in TT, FT, GH, COR, IGF-1, or E2.
Date: December 2015
Creator: Budnar, Jr., Ronald G.
Partner: UNT Libraries

Characterizing the Molecular Changes of Austrofundulus limnaeus As It Develops Towards and Enters Diapause II

Description: Austrofundulus limnaeus is a species of annual killifish which inhabits ephemeral ponds in South America. The species is able to survive seasonally desiccating ponds due to their ability to produce robust embryos. The embryos of this species are capable of entering a developmental arrest, termed diapause II, which precedes the onset of drought. While in this arrested state embryos exhibit the greatest tolerance to anoxia of any characterized vertebrate at 25ºC. Furthermore, when raised at 30ºC, embryos escape the entrance to diapause II and go on to develop directly. Currently, little is known about the molecular mechanisms which induce and maintain this developmentally arrested state. In this study I have developed methods to analyze changes in histone modifications in the context of diapause II. Histone modifications were chosen due to their extreme conservation and well characterized role as modulators of gene expression in other systems. Results utilizing adapted immunobased assays show significant changes in the global amount of H3S10P, H3K27me and H3K4me, as the embryos progress from early embryogenesis through the exit of diapause. Additionally, it is revealed that there exists a degree of phenotypic plasticity with regards to the entrance into diapause II which is modulated by the environment (severe hypoxia 0.1% O2). This work builds a foundation for future histone modification studies and contributes the development of several tools to the field. This study contributes to a greater molecular understanding of the cue(s) which influence the remarkable phenomenon of obligate developmental arrest in a vertebrate embryo.
Date: December 2015
Creator: Toni, Lee S.
Partner: UNT Libraries

Environmental Modulation of the Onset of Air-breathing of the Siamese Fighting Fish and the Blue Gourami

Description: This study determined the effect of hypoxia on air-breathing onset and physiological and morphological characters in larvae of the air breathing fishes Trichopodus trichopterus and Betta splendens. Larvae were exposed intermittently (12/12 h daily) to 20, 17, and 14 kPa of PO2 from 1 to 40 days post-fertilization. Survival, onset of air breathing, wet body mass, O2, Pcrit were measured every 5 dpf. Hypoxia advanced by 4 days, and delayed by 9 days, the onset of air breathing in Betta and Trichopodus, respectively. Hypoxia increased larval body length, wet mass, and labyrinth organ respiratory surface of Betta, but did not affect these factors in Trichopodus. Hypoxic exposure increased O2 by 50-100% at each day throughout larval development in Betta, but had no effect on larval Trichopodus. Hypoxia decreased Pcrit in Betta by 37%, but increased Pcrit in Trichopodus by 70%. Larval Betta reared in hypoxia showed a modified heart rate:opercular rate ratio (3:1 to 2:1), but these changes did not occur in Trichopodus. Compared to Betta, the blood of Trichopodus had a higher P50 and much smaller Bohr and Root effects. These interspecific differences are likely due to ecophysiological differences: Betta is a non- obligatory air-breather after 36 dpf with a slow lifestyle reflected in its low metabolism, while Trichopodus is an obligatory air-breather past 32 dpf with an athletic fast lifestyle and accompanying high metabolism.
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Date: December 2015
Creator: Mendez Sanchez, Jose Fernando
Partner: UNT Libraries

The Role of Cysteinyl Leukotriene Receptor 2 in Thrombocyte Aggregation

Description: Cysteinyl leukotriene receptor 2, a G-protein coupled receptor known to be expressed and functional on human platelets. However, it seems that upon ligand activation the cysteinyl leukotriene receptor 2 activates a variety of signaling pathways in multiple cell types among different species. Previously, a former laboratory member Vrinda Kulkarni found cysteinyl leukotriene receptor 2 to be expressed on the surface of adult zebrafish thrombocytes. In this work I studied the characteristics of aggregation in adult zebrafish thrombocytes with the knockdown of cysteinyl leukotriene receptor 2. I used a newly developed knockdown method to study the function of cysteinyl leukotriene receptor 2. Knockdown of the cysteinyl leukotriene was confirmed using RT-PCR results showed p=.001, reduced sell surface level of expression of the cysteinyl leukotriene receptor 2 results showed that p=.002. I found that the knockdown of cysteinyl leukotriene receptor 2 results in prothrombotic thrombocytes by using flow cytometry p=.0001.
Date: December 2015
Creator: Reyna, Julianna
Partner: UNT Libraries

Impact of a Genetically Engineered Probiotic Therapy and IGF-1 Genomics in the PAHenu2 Mouse Model of PKU

Description: Absence of functional phenylalanine hydroxylase results in phenylketonuria (PKU). Viable treatments remain few, expensive and secondary conditions such as osteopenia occur in most PKU patients. Objective 1: Given the recently described roles of gut microbes to aid host digestion, an orally administered genetically engineered probiotic as the delivery vehicle for enzyme replacement therapy was created. The engineered probiotic, pHENOMMenal, produced phenylalanine ammonia lyase with significant production of trans-cinnamate (phenylalanine cleavage product) in vitro and resulted in a reduction of 515 μM in blood phenylalanine when fed to PKU animals for 14 days (from 2307µM ± 264µM to 1792µM ± 261µM, n = 6, P < 0.05). The control probiotic produced no change in blood phenylalanine. Thus, pHENOMMenal treatment in PKU mice demonstrated engineered microbes could compensate for a metabolic deficiency of the host. Objective 2: Evaluate the PAHenu2 mouse model of PKU for a genetic discrepancy causing ocular enlargement and delayed development observed only after the PAHenu2 mutation was crossed to the C57BL/6J mouse. When compared to healthy littermates, ELISA indicated a consistent but insignificant decrease in plasma IGF-1 and an increase in ocular IGF-1 in PKU animals. SNP screening demonstrated a differential inheritance of IGF-1 alleles in healthy and PKU animals based on PAH allele inheritance. Ocular and developmental phenotypes in the PAHenu2 colony match those described in previous IGF-1 studies. Understanding the IGF-1 inheritance discrepancy will enable better osteopenia research using PAHenu2 mice and allow breeding of a healthier mouse colony for continued research. Collectively the results from this work describe a new therapeutic approach for treatment of PKU as well as a better understanding of the PAHenu2 mouse model to study this disease.
Date: December 2015
Creator: Durrer, Katherine Elaine
Partner: UNT Libraries

Studies on Zebrafish Thrombocyte Function

Description: Thrombocytes are important players in hemostasis. There is still much to be explored regarding the molecular basis of the thrombocyte function. In our previous microarray analysis data, we found IFT122 (an intraflagellar transport protein known to be involved in cilia formation) transcripts in zebrafish thrombocytes. Given recent discoveries of non-ciliary roles for IFTs, we examined the possibility that IFT122 affects thrombocyte function. We studied the role of IFT122 in thrombocyte function. We also found that IFT122 plays a central role in thrombocyte activation initiated by the agonists ADP, collagen, PAR-1 peptide and epinephrine. Although the receptors for ADP, PAR-1 peptide and epinephrine are present in the zebrafish genome, the collagen receptor GPVI was missing. In this study, we identified G6fL as a collagen receptor in zebrafish thrombocytes. Furthermore, IFT knockdown results in reduction in Wnt signaling. The Wnt signaling has been shown to be involved in megakaryocyte proliferation and proplatelets production. Therefore, defects in IFT could lead to thrombocytopenia. Splenectomy is performed in humans to treat such conditions. Therefore, in this study we developed a survival surgery protocol for splenectomy. We have shown that number of thrombocytes and their microparticles increase following splenectomy in zebrafish. Thus overall the studies on thrombocyte function in zebrafish could enhance fundamental knowledge on hemostasis and may provide future target candidates for therapies.
Date: May 2017
Creator: Pulipakkam Radhakrishnan, Uvaraj
Partner: UNT Libraries

Effect of Acute Alcohol Ingestion on Resistance Exercise Induced mTORC1 Signaling in Human Muscle

Description: The purpose of this project was to further elucidate the effects post-exercise alcohol ingestion. This project had many novel aspects including using a resistance exercise (RE) only exercise design and the inclusion of women. To our knowledge, we are the first to investigate the effect of post-RE alcohol ingestion in women. In the first chapter of this project, information on the prevalence of alcohol use and the importance of skeletal muscle as a dynamic and metabolic tissue was provided. In chapter two, the effects of post-RE alcohol ingestion in men and women are detailed. The major findings of this study was that although RE elicited similar mTORC1 signaling both in men and in women, alcohol ingestion appeared to only attenuate RE-induced phosphorylation of the mTORC1 signaling pathway in men. The third chapter focused on examining the effects of post-RE alcohol ingestion on acute testosterone bioavailability. The primary findings of this study was that alcohol substantially elevated serum total and free testosterone concentrations during recovery from a bout of resistance exercise. The fourth chapter detailed factors that contribute to bone density in men. The major findings of this study was that young adult male long-distance runners who participated in resistance training at least once per week had greater bone mineral density than their non-resistance trained and non-exercise trained peers.
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Date: August 2015
Creator: Duplanty, Anthony A.
Partner: UNT Libraries

The Effectiveness of Hybrid Problem-Based Learning versus Manual-Based Learning in the Microbiology Laboratory

Description: Promising results from the use of problem-based learning (PBL) as a teaching method in medical programs have encouraged many institutions to incorporate PBL into their curricula. This study investigates how applying hybrid-PBL (H-PBL) in a microbiology laboratory impacts students' higher-order thinking as compared to applying a lecture-based pedagogy. The experimental design compared the learning outcomes of two groups of students: the control group and the H-PBL group, for whom PBL cases comprised 30% of the curriculum. Both groups were taught basic skills for the microbiology lab by the same instructor. Using the traditional teaching style for the control group, the instructor offered each student what they needed for their experiments. The H-PBL group practiced experimental design, data analysis, theory proposal, and created research questions by using six study cases that were closely linked to the area of study. The outcome was measured using a pre- and post- assessment consisting of 24 questions that was designed by following Bloom's taxonomy of learning levels. A one-way ANOVA was used to analyze the data. The results showed that for the first three levels of Bloom's taxonomy— knowledge, comprehension, and application—there were no statistically significant differences between the H-PBL and control group gain scores as determined by a one-way ANOVA. For the knowledge level, f (1, 78) = .232, and p = .632; for the comprehension level, f (1, 78) = .004, and p = .951; and for the application level f (1, 78) =. 028, and p =.863. On the other hand, the gain scores for the three higher levels—analysis, evaluation, and creativity—improved for the H-PBL group. The analysis level showed statistically significant differences, with f (1, 78) = 4.012, and p = .049. Also, there were statistically significant differences in students' performance at the evaluation level, with f (1, 78) = 11.495, ...
Date: May 2017
Creator: Alharbi, Najwa
Partner: UNT Libraries

Clustering Algorithms for Time Series Gene Expression in Microarray Data

Description: Clustering techniques are important for gene expression data analysis. However, efficient computational algorithms for clustering time-series data are still lacking. This work documents two improvements on an existing profile-based greedy algorithm for short time-series data; the first one is implementation of a scaling method on the pre-processing of the raw data to handle some extreme cases; the second improvement is modifying the strategy to generate better clusters. Simulation data and real microarray data were used to evaluate these improvements; this approach could efficiently generate more accurate clusters. A new feature-based algorithm was also developed in which steady state value; overshoot, rise time, settling time and peak time are generated by the 2nd order control system for the clustering purpose. This feature-based approach is much faster and more accurate than the existing profile-based algorithm for long time-series data.
Date: August 2012
Creator: Zhang, Guilin
Partner: UNT Libraries

Beta-adrenergic Blockade Via Atenolol and Its Effects on Blood Pressure, Heart Rate, and Renal Morphology in the Developing Chicken Gallus Gallus Domesticus

Description: Chicken embryos were chronically exposed to the ?1- blocker atenolol during one of three stages: mesonephros (E7-E9), mesonephros-metanephros (E11-E13), or metanephros (E15-E17). Mesonephros group hearts were larger than all other groups (P < 0.01). Mesonephros and metanephros group kidneys were larger than all remaining groups (P < 0.0001). The mesonephros group nephron number was ~40% lower than control values (P = 0.002). Glomerular areas were 26% and 18% larger than the control group in the mesonephros and metanephros groups, respectively (P < 0.001). These data suggest an E7-E9 critical window of cardiovascular and renal development for atenolol. Acute atenolol exposure in E15 embryos showed an increase in mean arterial pressure with all but the highest dose. All doses significantly decreased heart rate.
Date: December 2012
Creator: Rossitto Lopez, Josie Jovita
Partner: UNT Libraries

Effects of Peripheral Nerve Injury on the Cells of the Dorsal Root Ganglion: a Role for Primary Cilia

Description: Primary cilia are ubiquitous sensory organelles found on most cell types including cells of the dorsal root ganglia (DRG). The DRG are groups of peripheral neurons that relay sensory information from the periphery to the CNS. Other cell types in the DRG include a type of glial cell, the satellite glial cells (SGCs). The SGCs surround the DRG neurons and, with the neurons, form functional sensory units. Currently are no reports describing the numbers of DRG cells that have cilia. We found that 26% of the SGCs had primary cilia. The incidence of cilia on neurons varied with neuron size, a property that roughly correlates with physiological characteristics. We found that 29% of the small, 16% of the medium and 5% of the large neurons had primary cilia. Primary cilia have been shown to have a role in cell proliferation in a variety of cell types. In some of the cells the cilia mediate the proliferative effects of Sonic hedgehog (Shh). In the CNS, Shh signaling through primary cilia affects proliferation during development as well as following injury, but no studies have looked at this function in the PNS. The SGCs and neurons of the DRG undergo complex changes following peripheral nerve injury such as axotomy. One marked change seen after axotomy is SGC proliferation and at later stages, neuronal death. We found that following axotomy there is a significant increase in the percentage of SGCs with primary cilia. We also found a significant increase in the percentage of medium-sized neurons with primary cilia. In other experiments we tested the idea that Shh plays a role in SGC proliferation. When Shh signaling was blocked following axotomy we found decreased proliferation of SGCs. This is the first report of a change in the percentage of cells with cilia following injury in ...
Date: December 2012
Creator: Smith, Sarah K.
Partner: UNT Libraries

Somatostatin Receptors on Neuronal Cilia: Evidence for Neuroprotection

Description: Primary cilia are essential in brain development, as mediators of sonic hedgehog signaling. However, their role in mature neurons remains elusive. One means to elucidate their function may be to investigate the function of the somatostatin type 3 receptor (SstR3), which is concentrated on the primary cilia of neurons. The inhibitory and anticonvulsant properties of somatostatin suggest that ciliary SstR3 might protect neurons against excitotoxicity, as seen in epileptic seizures. C57BL/6 wild type (wt) and SstR3 knockout mice were administered vehicle or epileptogenic agents kainic acid (KA) or pentylenetetrazole. Seizure behaviors were rated on seizure severity scales. KA-induced seizure behaviors were more severe in SstR3 mutants than in wt. Correspondingly, the mutants showed greater reactive gliosis, as indicated by increased numbers of GFAP immunoreactive (GFAP(+)) astrocyte processes. In addition, seizure severity was associated with a greater percentage of neural stem cells having an ACIII(+) cilium. Following injections of pentylenetetrazole, SstR3 mutants reached maximum seizure levels faster than wt. These results support the hypothesis that ciliary SstR3 are neuroprotective in mature neurons, and may provide a new avenue for the treatment of seizures.
Date: December 2012
Creator: Evans, Shakila K.
Partner: UNT Libraries

Chronic Hypoxia and Hyperoxia Modifies Morphology and Vegf Expression of the Lungs of the Developing Chicken (Gallus Gallus Domesticus)

Description: This study determines effects of oxygen levels on morphology and VEGF expression of developing chicken lungs following incubation in normoxia (21% O2), hypoxia (15% O2) or hyperoxia (30% O2), until developmental days 16 or 18. Lung morphology was assessed using light microscopy, while VEGF expression was determined with ELISA. In hypoxia, the proportion of parabronchial tissue and parabronchi including lumina increased from day 16 to 18 (61 to 68% and 74.2 to 82.2%, respectively). Non-parabronchial tissue was higher in hypoxia than in hyperoxia on day 16 (26 to 20%). However, by day 18, there were no differences between groups. VEGF expression was 33% higher in hypoxia than in hyperoxia on day 16 (736 vs. 492 pg/ml). On day 18, VEGF expression was 43% higher in hyperoxia than in normoxia (673 to 381pg/ml), and remained elevated by 40% in hypoxia over normoxia (631 pg/ml). VEGF may be a mechanism by which parabronchial tissue is stimulated from day 16 to 18 following exposure to chronic hypoxia.
Date: December 2012
Creator: Lewallen, Melissa Anjanette
Partner: UNT Libraries

Head Trauma Release of Histamine from Dural Mast Cells Alters Blood-Brain Barrier: Attenuation with Zolantidine

Description: This study employed a new model of mild-to-moderate head trauma to specifically identify the role of dural mast cell (MC) histamine in trauma-induced increased permeability in the blood-brain barrier (BBB). A single line was scored partially through the left dorsal parietal skull. Immediately following the trauma, degranulation was seen in 39% of the MCs on the left and in 2% on the right. After a 20 min survival period, left duras showed 55% with MC degranulation (fewer with complete degranulation) compared to 34% on the right. In the other experiments two parallel lines were scored following the injection of Evan's blue. Histamine assay showed histamine increased in the left cortex to 154% at 5 min, 174% at 10 min, and 151% at 20 min. Fluorescent quantitation of extravasated Evan's blue at 20 min following the trauma gave an increase of 1385% over the value measured for the right cortex. Zolantidine, a selective histamine H2 receptor antagonist, administered at 10- and 20- mg/kg 30 min before the trauma blocked 65% of the Evan's blue extravasation compared with the control and 2.5 mg group.
Date: December 2000
Creator: Laufer, Susan R.
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Syllabus Outline for Genetics Lecture and Laboratory

Description: This work is intended to be used as a teaching tool in conjunction with the text cited. It is written in outline format, highlighting the major concepts of each pertinent chapter. In this format, the concepts can be expanded upon at the discretion of the instructor. This work is to be used as a guide for lecture. The basic concepts contained in the outline are in such a format as to be able to work in more information regarding the subject matter if needed. The instructor can work from this outline as a starting point. Major topics in the chapters are highlighted, making lecture notes for the instructor easier to do.
Date: December 1999
Creator: Preston, E. Lynn
Partner: UNT Libraries