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  Partner: UNT Libraries
 Department: Department of Biological Sciences
 Decade: 2010-2019
 Collection: UNT Theses and Dissertations
Acute Effects of the Antibiotic Streptomycin on Neural Network Activity and Pharmacological Responses

Acute Effects of the Antibiotic Streptomycin on Neural Network Activity and Pharmacological Responses

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Date: December 2014
Creator: Zeng, Wei Rong
Description: The purpose of this study is to find out that if antibiotic streptomycin decreases neuronal network activity or affects the pharmacological responses. The experiments in this study were conducted via MEA (multi-electrode array) technology which records neuronal activity from devices that have multiple small electrodes, serve as neural interfaces connecting neurons to electronic circuitry. The result of this study shows that streptomycin lowered the spike production of neuronal network, and also, sensitization was seen when neuronal network pre-exposed to streptomycin.
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Adaptive Advantages of Carotenoid Pigments in Alpine and Subalpine Copepod Responses to Polycyclic Aromatic Hydrocarbon Induced Phototoxicity

Adaptive Advantages of Carotenoid Pigments in Alpine and Subalpine Copepod Responses to Polycyclic Aromatic Hydrocarbon Induced Phototoxicity

Date: May 2010
Creator: Kovach, Matthew James
Description: Alpine zooplankton are exposed to a variety of stressors in their natural environment including ultraviolet radiation. Physiological coping mechanisms such as the accumulation of photoprotective compounds provide these zooplankton protection from many of these stressors. Elevated levels of carotenoid compounds such as astaxanthin have been shown to help zooplankton survive longer when exposed to ultraviolet radiation presumably due to the strong antioxidant properties of carotenoid compounds. This antioxidant capacity is important because it may ameliorate natural and anthropogenic stressor-induced oxidative stress. While previous researchers have shown carotenoid compounds impart increased resistance to ultraviolet radiation in populations of zooplankton, little work has focused on the toxicological implications of PAH induced phototoxicity on zooplankton containing high levels of carotenoid compounds. This thesis discusses research studying the role that carotenoid compounds play in reducing PAH induced phototoxicity. By sampling different lakes at elevations ranging from 9,500' to 12,700' in the front range of the Colorado Rocky Mountains, copepod populations containing different levels of carotenoid compounds were obtained. These populations were then challenged with fluoranthene and ultraviolet radiation. Results discussed include differences in survival and levels of lipid peroxidation among populations exhibiting different levels of carotenoid compounds, and the toxicological and ecological implications of ...
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Aging Is a Determinant in Anoxia Stress Tolerance in Caenorhabditis Elegans

Aging Is a Determinant in Anoxia Stress Tolerance in Caenorhabditis Elegans

Date: May 2013
Creator: Goy, Jo M.
Description: Oxygen availability is critical for survival for most organisms. The nematode, C. elegans, has been useful for studying genetic regulation of anoxia tolerance due to the oxygen deprivation response mechanisms shared with other metazoans. Studies examining long-term anoxia (72h, LTA) tolerance have only been conducted at adult day 1. To investigate the effect of aging on anoxia tolerance wild-type and mutant strains were exposed to LTA between adult day 1 and day 9. Wild-type isolates and daf-16(mu86) (FOXO transcription factor regulated by insulin-signaling) and aak-2(gt33) (catalytic subunit of AMP-activated protein kinase) strains were anoxia sensitive at day 1 and displayed increased LTA tolerance with aging correlated with reproductive senescence followed by a decline in survivorhsip through day 9. The daf-2(e1370) (insulin receptor homologue of C. elegans), glp-1(e2141) (a lin-12/Notch receptor) and fog-2(q71) (required for spermatogenesis) strains were LTA-tolerant through day 5. I conclude that aging influences LTA-tolerance in a strain- and age-dependent manner. In addition to being LTA-tolerant the daf-2(e1370) and glp-1(e2141) strains have a longevity phenotype that is suppressed by loss of kri-1 or daf-12. While loss of kri-1 did not suppress the LTA-tolerant phenotype of glp-1(e2141) at day 1 the portion of impaired survivors increased at day 3 ...
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Alterations in Fatty Acid Amide Hydrolase (Faah) Transcript Levels and Activity Lead to Changes in the Abiotic Stress Susceptibility of Arabidopsis Thaliana

Alterations in Fatty Acid Amide Hydrolase (Faah) Transcript Levels and Activity Lead to Changes in the Abiotic Stress Susceptibility of Arabidopsis Thaliana

Date: May 2012
Creator: Gonzalez, Gabriel
Description: N-Acylethanolamines (NAEs) are a class of bioactive lipids, and FAAH is one of the enzymes responsible for degrading NAEs in both plants and animals. in plants, FAAH appears to be closely associated with ABA, a phytohormone which has long been associated with plant stress responses, since the overexpression of FAAH in Arabidopsis results in ABA hypersensitivity. Therefore, it is reasonable to speculate that alterations in FAAH transcript levels will result in altered stress responses in plants. to investigate this hypothesis experiments were carried out in which wild type (WT), FAAH-overexpressing (OE), and T-DNA insertional FAAH knockouts of Arabidopsis (faah) were grown in MS media under stress conditions. the stress conditions tested included chilling stress, heavy metal stress induced by cadmium or copper, nutrient limitations induced by low phosphorus or low nitrogen, salt stress induced with NaCl, and osmotic stress induced with mannitol. the OE plants were consistently hypersensitive to all stress conditions in relation to wild type plants. Inactive FAAH overexpressors did not have the hypersensitivity to the salt and osmotic stress of the active OE plants and were instead tolerant to these stresses. FAAH2 (faah2) knockouts and FAAH 1 and 2 double knockouts (faah 1+2) were based on some ...
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Anatomical and Morphological Responses of Cardiospermum Halicacabum L. (Balloon Vine), to Four Levels of Water Availability

Anatomical and Morphological Responses of Cardiospermum Halicacabum L. (Balloon Vine), to Four Levels of Water Availability

Date: May 2011
Creator: Dempsey, Matthew Anthony
Description: C. halicacabum (Sapindaceae) is an invasive plant that is considered a nuisance species in Texas riparian environments. Little is known of the tolerance of C. halicacabum to flooding and drought; however, this information may provide insight into the characteristics that contribute to C. halicacabum purported invasiveness. C. halicacabum seedlings (n = 92) were exposed to one of four levels of water availability (flooded, saturated, intermediate and dry) over six weeks under greenhouse conditions. Plant performance was affected by water availability; however, there was no effect on survivorship. Flooded and saturated plants exhibited morphological adaptations; producing adventitious roots, hypertrophy, and aerenchyma tissue. Morphological measures, anatomical responses, and patterns of biomass allocation all indicate that C. halicacabum is able to survive periodic inundation, perform in saturation, and establish and thrive on the drier end of a moisture gradient.
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Benthic Macroinvertebrates of Temperate, Sub-Antarctic Streams: The Effects of Altitudinal Zoning and Temperature on the Phenology of Aquatic Insects Associated to the Robalo River, Navarino Island (55°S), Chile

Benthic Macroinvertebrates of Temperate, Sub-Antarctic Streams: The Effects of Altitudinal Zoning and Temperature on the Phenology of Aquatic Insects Associated to the Robalo River, Navarino Island (55°S), Chile

Date: December 2011
Creator: Contador Mejías, Tamara Andrea
Description: The Cape Horn Biosphere Reserve, within the remote Sub-Antarctic ecoregion is a reservoir of expressions of biological and cultural diversity. Although it is considered one of 24 wilderness areas remaining in the world, it is not free from local and global threats, such as invasive species, and climate change. Field biologists and philosophers associated to the Sub-Antarctic Biocultural Conservation Program and the Omora Ethnobotanical Park, have worked to describe the region’s biocultural diversity, linking ecological and philosophical research into education, ecotourism, and conservation, through a methodology called field environmental philosophy (FEP), which integrates ecological sciences and environmental ethics through a 4-step cycle consisting of: 1) interdisciplinary research; 2) composition of metaphors; 3) design of field activities with an ecological and ethical orientation; and 4) implementation of in situ conservation areas. In this context, the purposes of this dissertation were to: 1) provide a comprehensive review of publications regarding the conservation status of aquatic and terrestrial insects at a global scale and with an emphasis in southern South America; 2) study the distribution of benthic macroinvertebrates through the sharp altitudinal gradient of the Róbalo River watershed; 3) describe the life histories of Gigantodax sp (Simuliidae: Diptera) and Meridialaris chiloeense (Leptophlebiidae: Ephemeroptera) ...
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Beta-adrenergic Blockade Via Atenolol and Its Effects on Blood Pressure, Heart Rate, and Renal Morphology in the Developing Chicken Gallus Gallus Domesticus

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

Date: December 2012
Creator: Rossitto Lopez, Josie Jovita
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.
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Bioconcentration and Morphological Effects of Triclosan on Three Species of Wetland Plants

Bioconcentration and Morphological Effects of Triclosan on Three Species of Wetland Plants

Date: May 2013
Creator: Smith, Caleb M.
Description: Triclosan (TCS) is an antimicrobial compound found in several types of common household products. After being washed down the drain, TCS will then end up in the local watershed. Although numerous studies have been conducted to evaluate the fate and effects of TCS in aquatic environments, there have been no studies evaluating the role arbuscular mycorrhizal fungi (AM) play in a plants response to TCS exposure. Three species of wetland plants native North Texas were inoculated with AM spores and exposed to 0, 0.4 g/L and 4.0 g/L TCS concentrations. Root morphology of E. prostrata and S. herbacea showed AM and exposure responses. S. herbacea produced the greatest amounts biomass and TCS bioaccumulation, in all but one treatment. It also displayed opposing results to E. prostrata in measures of root length, root surface area, relative root mass, relative shoot mass and shoot:root ratio. TCS root tissue concentrations increased with increased exposures for both E. prostrata and S. herbacea. Even though E. prostrata had the lowest levels in each measure of biomass production, it had the highest amount of root TCS bioaccumulation in the AM inoculated 4.0 g/L treatment. H. laevis was between the other two species in terms of biomass ...
Contributing Partner: UNT Libraries
Bioconcentration of Triclosan, Methyl-Triclosan, and Triclocarban in the Plants and Sediments of a Constructed Wetland

Bioconcentration of Triclosan, Methyl-Triclosan, and Triclocarban in the Plants and Sediments of a Constructed Wetland

Date: August 2011
Creator: Zarate, Frederick M., Jr.
Description: Triclosan and triclocarban are antimicrobial compounds added to a variety of consumer products that are commonly detected in waste water effluent. The focus of this study was to determine whether the bioconcentration of these compounds in wetland plants and sediments exhibited species specific and site specific differences by collecting field samples from a constructed wetland in Denton, Texas. The study showed that species-specific differences in bioconcentration exist for triclosan and triclocarban. Site-specific differences in bioconcentration were observed for triclosan and triclocarban in roots tissues and sediments. These results suggest that species selection is important for optimizing the removal of triclosan and triclocarban in constructed wetlands and raises concerns about the long term exposure of wetland ecosystems to these compounds.
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Biodiversity and Genetic Structure of Benthic Macroinvertebrates along an Altitudinal Gradient: A Comparison of the Windhond and Róbalo River Communities on Navarino Island, Chile

Biodiversity and Genetic Structure of Benthic Macroinvertebrates along an Altitudinal Gradient: A Comparison of the Windhond and Róbalo River Communities on Navarino Island, Chile

Date: May 2016
Creator: Pulliam, Lauren
Description: Altitudinal gradients in Sub-Antarctic freshwater systems present unique opportunities to study the effect of distinct environmental gradients on benthic macroinvertebrate community composition and dispersal. This study investigates patterns in biodiversity, dispersal and population genetic structure of benthic macroinvertebrate fauna across an altitudinal gradient between two watersheds on Navarino Island in southern Chile. Patterns in diversity, density, evenness and functional feeding groups were not significantly different across the altitudinal gradient in both the Windhond and Róbalo Rivers. Taxa richness in both rivers generally increased from the headwaters of the river to the mouth, and functional feeding group patterns were consistent with the predictions of the River Continuum Concept. Population genetic structure and gene flow was investigated by sampling the mitochondrial cytochrome oxidase I gene in two invertebrate species with different dispersal strategies. Hyalella simplex (Amphipoda) is an obligate aquatic species, and Meridialaris chiloeense (Ephemeroptera) is an aquatic larvae and a terrestrial winged adult. Contrasting patterns of population genetic structure were observed. Results for Hyalella simplex indicate significant differentiation in genetic structure in the Amphipod populations between watersheds and lower genetic diversity in the Róbalo River samples, which may be a result of instream dispersal barriers. Meridialaris chiloeense exhibited weak population structure ...
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brk1 and dcd1 Act Synergistically in Subsidiary Cell Formation in Zea mays

brk1 and dcd1 Act Synergistically in Subsidiary Cell Formation in Zea mays

Date: August 2014
Creator: Malhotra, Divya
Description: Subsidiary mother cell (SMC) divisions during stomatal complex formation in Zea mays are asymmetric generating a small subsidiary cell (SC) and a larger epidermal cell. Mutants with a high number of abnormally shaped subsidiary cells include the brick1 (brk1) and discordia1 (dcd1) mutants. BRK1 is homologous to HSPC300, an ARP2/3 complex activator, and is involved in actin nucleation while DCD1 is a regulatory subunit of the PP2A phosphatase needed for microtubule generation (Frank and Smith, 2002; Wright et al. 2009). Possible causes of the abnormal SCs in brk1 mutants include a failure of the SMC nucleus to polarize in advance of mitosis, no actin patch, and transverse and/or no PPBs (Gallagher and Smith, 2000; Panteris et al 2006). The abnormal subsidiary mother cell division in dcd1 is due to correctly localized, but disorganized preprophase bands (PPBs; Wright et al. 2009). The observation that brk1 has defects in PPB formation and that the dcd1 phenotype is enhanced by the application of actin inhibitors led us to examine the dcd1; brk1 double mutant (Gallagher and Smith, 1999). We found that dcd1; brk1 double mutants demonstrate a higher percentage of aberrant SCs than the single mutants combined suggesting that these two mutations have ...
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Characteristics of Primary Cilia and Centrosomes in Neuronal and Glial Lineages of the Adult Brain

Characteristics of Primary Cilia and Centrosomes in Neuronal and Glial Lineages of the Adult Brain

Access: Use of this item is restricted to the UNT Community.
Date: May 2015
Creator: Bhattarai, Samip Ram
Description: Primary cilia are sensory organelles that are important for initiating cell division in the brain, especially through sonic hedgehog (Shh) signaling. Several lines of evidence suggest that the mitogenic effect of Shh requires primary cilia. Proliferation initiated by Shh signaling plays key roles in brain development, in neurogenesis in the adult hippocampus, and in the generation of glial cells in response to cortical injury. In spite of the likely involvement of cilia in these events, little is known about their characteristics. Centrosomes, which are associated with primary cilia, also have multiple influences on the cell cycle, and they are important in assembling microtubules for the maintenance of the cell’s cytoskeleton and cilia. The cilia of terminally differentiated neurons have been previously examined with respect to length, incidence, and receptors present. However, almost nothing is known about primary cilia in stem cells, progenitors, or differentiated glial cells. Moreover, it is not known how the properties of cilia and centrosomes may vary with cell cycle or proliferative potential, in brain or other tissues. This dissertation focuses first on neurogenesis in the hippocampal subgranular zone (SGZ). The SGZ is one of the few brain regions in mammals that gives rise to a substantial ...
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Characterization of Arthrobacter Globiformis Aspartate Transcarbamylase Concentrations of Substrates

Characterization of Arthrobacter Globiformis Aspartate Transcarbamylase Concentrations of Substrates

Date: December 2012
Creator: Wright, Jackie
Description: This thesis consists of one major section with two subsections. The first subsection investigates the activity of Arthrobacter globiformis aspartate transcarbamylase's specific activity with increasing concentrations of the enzyme's substrate. Dihydroorotase (DHOase) activity was also measured with increasing concentrations of the substrate dihydroorotate. The second subsection collected data in order to classify the enzyme, resulting in a classification into the category of class A ATCases with bifunctional ATCase-DHOase complexes. The thesis provides evidence to broaden understanding of the ATCase and DHOase enzymes for members of the family that Arthrobacter belongs to.
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A Characterization Of Jackson Blue Spring, Jackson County, Florida

A Characterization Of Jackson Blue Spring, Jackson County, Florida

Date: December 2011
Creator: Reiser, Cora
Description: Jackson Blue is a first magnitude spring in the karst terrane of northeast Florida. Previous studies have identified inorganic fertilizer as the source of high nitrate levels in the spring. Agricultural land use and karst vulnerability make Jackson Blue a good model for conservation concerns. This work offers an aggregation of studies relating to the springshed, providing a valuable tool for planning and conservation efforts in the region. An analysis of nitrate levels and other water quality parameters within the springshed did not reveal significantly different values between agricultural and forested land use areas. Confounding factors include: high transmissivity in the aquifer, interspersed land use parcels, and fertilizer application in forested areas due to commercial pine stand activity.
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Characterization of Triclocarban, Methyl- Triclosan, and Triclosan in Water, Sediment, and Corbicula Fluminea (Müller, 1774) Using Laboratory, in Situ, and Field Assessments

Characterization of Triclocarban, Methyl- Triclosan, and Triclosan in Water, Sediment, and Corbicula Fluminea (Müller, 1774) Using Laboratory, in Situ, and Field Assessments

Date: May 2011
Creator: Edziyie, Regina E.
Description: In the last decade emerging contaminants research has intensified in a bid to answer questions about fate, transport, and effects as these chemicals as they get released into the environment. The chemicals of interest were the antimicrobials; triclocarban (TCC) and triclosan (TCS), and a metabolite of triclosan, methyl triclosan (MTCS). This research was designed to answer the question: what is the fate of these chemicals once they are released from the waste water treatment plant into receiving streams. Three different assessment methods; field monitoring, in-situ experiments, and laboratory studies were used to answer the overall question. TCS, TCC, and MTCS levels were measured in surface water, sediment and the Asiatic clam Corbicula fluminea. Field studies were conducted using four sites at Pecan Creek, Denton TX. Levels of all three chemicals in clams were up to fives orders of magnitude the water concentrations but an order of magnitude lower than in sediment. Highest sediment levels of chemicals were measured in samples from the mouth of Pecan Creek (highest organic matter). TCC was the most and TCS was the least accumulated chemicals. In-situ and lab studies both indicated that uptake of these chemicals into the clams was very rapid and measurable within ...
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Chronic Hypoxia and Hyperoxia Modifies Morphology and Vegf Expression of the Lungs of the Developing Chicken (Gallus Gallus Domesticus)

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

Date: December 2012
Creator: Lewallen, Melissa Anjanette
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.
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Cloacal Microbiota of Captive-bred and Wild Attwater’s Prairie-chicken, Tympanuchus Cupido Attwateri

Cloacal Microbiota of Captive-bred and Wild Attwater’s Prairie-chicken, Tympanuchus Cupido Attwateri

Date: August 2014
Creator: Simon, Stephanie E.
Description: The Attwater’s prairie-chicken (Tympanuchus cupido attwateri; APC) is a species of grouse native to Texas coastal prairies and is on the critically endangered species list as a result of habitat destruction and overhunting. All of the current populations were captively bred and released into the wild. Survivorship for released APCs is very low, and individuals seldom survive to reproduce in the wild. One factor contributing to this may be an alteration in the gut microbiota as a result of captivity. Factors potentially influencing the gut microbial composition in captivity include antibiotic therapy, stress, and a predominantly commercially formulated diet. Recent studies have begun to shed light on the importance of the host microbial endosymbionts. Antibiotic administration, stress, diet, age, genotype and other factors have been shown to influence microbial populations in the gastrointestinal tracts of many different vertebrates. Sequencing of 16S rRNA gene amplicons on the Ion Torrent™ platform was used in this study to identify groups of bacteria in the cloacas as a surrogate for the gut microbiota in the APC. Antibiotic-treated and untreated birds, wild-hatched and captive-bred birds, and individuals sampled before and after release to the wild were examined. Significant differences were found between wild-hatched and captive ...
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Clustering Algorithms for Time Series Gene Expression in Microarray Data

Clustering Algorithms for Time Series Gene Expression in Microarray Data

Date: August 2012
Creator: Zhang, Guilin
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.
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Comparative Phyto-uptake Across Distribution Coefficients of Pharmaceutical Compounds and Aquatic Macrophytes: Carbamazepine and Amiodarone Uptake in Lemna Spp

Comparative Phyto-uptake Across Distribution Coefficients of Pharmaceutical Compounds and Aquatic Macrophytes: Carbamazepine and Amiodarone Uptake in Lemna Spp

Date: August 2013
Creator: Woodard, Jennifer Kristin
Description: Few studies have been conducted on the effectiveness of phytoremediation of pharmaceutical compounds, although the persistent and non-acutely toxic nature of many of these compounds in today's water bodies may yield an ideal application for this practice. To quantify the potential effectiveness of plant uptake, kinetic and proportional bioconcentration factors (BCFk, and BCFp, respectively) in nanograms (ng) carbamazepine and amiodarone per gram (g) wet weight plant tissue for Lemna spp. were determined utilizing a 14-day continuous flow-through study. Samples were analyzed using isotope dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) running in positive ion mode. Kinetic BCF was estimated at 0.538, while proportional BCF was estimated at 0.485. Kinetic BCF for the amiodarone study was estimated at 23.033, whereas proportional BCF was estimated at 41.340. Possible contamination of the C18 column and peristaltic pump failure may have impacted uptake results. In light of variability and current lack of research in the field, this work should be considered exploratory rather than conclusive.
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Comparison of Heteranthera Dubia (Jacq.) MacM.-associated Macroinvertebrates Between Georgraphical Regions in the United States

Comparison of Heteranthera Dubia (Jacq.) MacM.-associated Macroinvertebrates Between Georgraphical Regions in the United States

Date: May 2010
Creator: Harms, Nathan Earl
Description: Macroinvertebrates associated with the aquatic plant, water stargrass (Heteranthera dubia), were sampled from 12 waterbodies in four regions of the United States from June to August 2005. Taxa richness, evenness, and diversity were lowest in the Lower Midwest (LMW) region, and higher in Northern sites, especially the Upper Midwest (UMW), and Northeast (NE). While relative abundance varied from site to site and region to region, utilization of the plant by functional groups remained fairly constant. Collector-gatherers consistently comprised the largest portion of invertebrates sampled. The shredder/ herbivore functional group comprised an average of 17 % of total groups. Through an exhaustive literature review, it was found that shredder/ herbivores of water stargrass have not been reported in the literature. Because of this, the herbivore group was analyzed separately and consisted of 2,383 specimens representing 23 species. The most common groups were Rhopalosiphum sp., Nectopsyche spp. and chironomids. No differences were found in herbivore diversity or evenness between sampling regions, but species richness was significantly different.
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A Comparison of Mercury Localization, Speciation, and Histology in Multiple Fish Species From Caddo Lake, a Fresh Water Wetland

A Comparison of Mercury Localization, Speciation, and Histology in Multiple Fish Species From Caddo Lake, a Fresh Water Wetland

Date: May 2012
Creator: Smith, James Durward
Description: This work explores the metabolism of mercury in liver and spleen tissue of fish from a methylmercury contaminated wetland. Wild-caught bass, catfish, bowfin and gar were collected. Macrophage centers, which are both reactive and primary germinal centers in various fish tissues, were hypothesized to be the cause of demethylation of methylmercury in fish tissue. Macrophage centers are differentially expressed in fish tissue based on phylogenetic lineage, and are found primarily in the livers of preteleostean fish and in the spleen of teleostean fish. Histology of liver and spleen was examined in both control and wild-caught fish for pathology, size and number of macrophage centers, and for localization of mercury. Total mercury was estimated in the muscle tissue of all fish by direct mercury analysis. Selenium and mercury concentrations were examined in the livers of wild-caught fish by liquid introduction inductively coupled plasma mass spectrometry (ICP-MS). Total mercury was localized in histologic sections by laser ablation ICP-MS (LA-ICP-MS). Mercury speciation was determined for inorganic and methylmercury in liver and spleen of fish by bas chromatography-cold vapor atomic fluorescence spectroscopy (GC-CVAFS). Macrophage center tissue distribution was found to be consistent with the literature, with a predominance of centers in preteleostean liver and ...
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Cytochrome P450 Gene Expression Modulates Anoxia Sensitivity in Caenorhabditis Elegans

Cytochrome P450 Gene Expression Modulates Anoxia Sensitivity in Caenorhabditis Elegans

Date: August 2016
Creator: Quan, Daniel L
Description: With an increasing population suffering from obesity or Diabetes Mellitus (DM), it is more pertinent than ever to understand how physiological changes impact cellular processes. Patients with DM often suffer from obesity, hyperglycemia, altered fatty acids that contribute to vascular dysfunction, and increased risk to ischemia. Caenorhabditis elegans is a model system used to study the conserved insulin signaling pathway, cellular responses in whole organisms and the impact a glucose diet has on oxygen deprivation (anoxia) responses. RNA-sequencing (RNA-Seq) was used to analyze the expression of genes in the anoxia sensitive populations of N2 (wild-type) fed glucose and hyl-2(tm2031), a mutant with altered ceramide metabolism. Comparison of the altered transcripts in the anoxia sensitive populations revealed 199 common transcripts- 192 upregulated and 7 downregulated. One of the gene families that have altered expression in the anoxia sensitive populations encode for Cytochrome P450 (CYP). CYPs are located both in the mitochondria and endoplasmic reticulum (ER), but the CYPs of interest are all predicted to be mainly subcellularly localized to the ER. Here, I determined that knock-down of specific cyp genes, using RNA interference (RNAi), increased anoxia survival in N2 animals fed a standard diet. Anoxia sensitivity of the hyl-2(tm2031) animals was ...
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Cytotoxicity and Functional Toxicity of Mefloquine and Search for Protective Compounds

Cytotoxicity and Functional Toxicity of Mefloquine and Search for Protective Compounds

Date: May 2015
Creator: Holmes, Katelyn
Description: Mefloquine hydrochloride is an antimalarial agent that has been used for the past 40 years. Numerous reports of neurological side effects have recently led the FDA to issue a strong warning regarding long-term neurological effects. This warning lead to the U.S. Army’s Special Forces and other components to discontinue its use in July of 2013. Despite reported adverse side effects, mefloquine remains in circulation and is recommended to travelers going to specific Asian countries. Mefloquine has been used as a treatment for those already infected with the malaria parasite (blood concentrations ranging from 2.1 to 23 µM), and as prophylaxis (blood concentrations averaging 3.8 µM) (Dow 2003). The purpose of this study was to quantify Mefloquine’s toxicity using spontaneously active nerve cell networks growing on microelectrode arrays in vitro and to identify compounds that alleviate or reduce toxic effects. The current literature on mefloquine toxicity is lacking electrophysiological data. These data will contribute to research on the mechanism of adverse side effects associated with mefloquine use. Sequential titration experiments were performed by adding increasing concentrations of mefloquine solution to cultured neurons. Network responses were quantified and reversibility was examined. In each network, activity decreases were normalized as a percent of ...
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Designing Tools to Probe the Calcium-dependent Function of Arabidopsis Tonneau2

Designing Tools to Probe the Calcium-dependent Function of Arabidopsis Tonneau2

Access: Use of this item is restricted to the UNT Community.
Date: December 2013
Creator: Oremade, Oladapo O.
Description: Plants possess unique features in many aspects of development. One of these features is seen in cell wall placement during cytokinesis, which is determined by the position of the preprophase band (PPB) and the subsequent expansion of the phragmoplast that deposits the new cell wall. During phragmoplast expansion, the phragmoplast tracks to the cortical division site, which was delineated by the PPB. Thus the position of the PPB determines the orientation of the division plane. In Arabidopsis thaliana, TONNEAU2 (TON2) is required for PPB formation and has been shown to interact with a type A subunit of the PP2A phosphatase in the yeast two-hybrid system. In Arabidopsis tonneau2 (ton2) mutants, abnormalities of the cortical microtubule cytoskeleton, such as disorganization of the interphase microtubule array and lack of PPB formation before mitosis markedly affects cell shape and arrangement as well as overall plant morphology. Loss of dcd1/add1, the maize ton2 homologues gives rise to a similar phenotype in Zea mays. The TON2 protein has two EF hand domains which are calcium-binding sites. Since calcium has been known to play key roles in several areas of plant functioning, the following question was raised: “Does calcium binding contribute to the localization and function ...
Contributing Partner: UNT Libraries
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