Phenotype Analysis of the CISD Gene Family Relative to Mitochondrial Function in Caenorhabditis elegans

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NEET proteins belong to a unique class of [2Fe-2S] cluster proteins that have been shown to participate in various biological processes such as regulating iron, reactive oxygen species and apoptosis within the cell and are localized to the mitochondria. Disruption of the mitochondrial NEET proteins are associated with different human diseases such as obesity, neurodegeneration, cancer and diabetes. In humans, a missense mutation in the CISD2 gene results in a heritable multisystem disorder termed Wolfram syndrome 2 (WFS2), a disease which displays an early onset of juvenile diabetes and various neuropsychiatric disorders. The C. elegans genome contains three previously uncharacterized cisd genes: cisd-1, which has homology to the human CISD1 and CISD2, and cisd-3.1 and cisd-3.2, both of which have homology to the human CISD3. Disruption of the cisd-3 gene(s) function results in mis-regulation of proteostasis in the mitochondria, whereas cisd-1 and cisd-3.1 disruption impacts proteostasis in the endoplasmic reticulum. Reduction of cisd-3.2 gene function also leads to a developmental delay in C. elegans. A knockout mutation of the cisd-3.2(pn68) gene function results in various germline defects including delayed development progression and morphological defects. Furthermore, I show the cisd gene(s) and protein expression profiles is present relative to sex, tissue …
Date: December 2019
Creator: Mungwira, Chipo F
System: The UNT Digital Library

Determination of Dissociation Constants for GABAA Receptor Antagonists using Spontaneously Active Neuronal Networks in vitro

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Changes in spontaneous spike activities recorded from murine frontal cortex networks grown on substrate-integrated microelectrodes were used to determine the dissociation constant (KB) of three GABAA antagonists. Neuronal networks were treated with fixed concentrations of GABAA antagonists and titrated with muscimol, a GABAA receptor agonist. Muscimol decreased spike activity in a concentration dependent manner with full efficacy (100% spike inhibition) and a 50% inhibitory concentration (IC50) of 0.14 ± 0.05 µM (mean ± SD, n=6). At 10, 20, 40 and 80 µM bicuculline, the muscimol IC50 values were shifted to 4.3 ± 1.8 µM (n=6), 6.8 ± 1.7 µM (n=6), 19.3 ± 3.54 µM (n=10) and 43.5 µM (n=2), respectively (mean ± SD). Muscimol titration in the presence of 10, 20, 40 µM of gabazine resulted in IC50s values of 20.1 (n=2), 37.17 (n=4), and 120.45 (n=2), respectively. In the presence of 20, 80, and 160 µM of TMPP (trimethylolpropane phosphate) the IC50s were 0.86 (n=2), 3.07 (n=3), 6.67 (n=2) µM, respectively. Increasing concentrations of GABAA antagonists shifted agonist log concentration-response curves to the right with identical efficacies, indicating direct competition for the GABAA receptor. A Schild plot analysis with linear regression resulted in slopes of 1.18 ± 0.18, 1.29 …
Date: December 2005
Creator: Oli-Rijal, Sabnam
System: The UNT Digital Library

Pyrimidine Enzyme Specific Activity at Four Different Phases of Growth in Minimal and Rich Media, and Concomitant Virulence Factors Evaluation in Pseudomonas aeruginosa

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Pseudomonas aeruginosa is a Gram-negative rod, aerobic, non-fermenting, oxidase positive, pigment producing, and nutritionally versatile bacterium. Infections by P. aeruginosa are the most important cause of morbidity and mortality in immunocompromised patients, given virulence factor production that suppresses antibiotic therapy and promotes persistent infection. This research is the first comprehensive report of the pyrimidine biosynthetic pathway for all phases of growth in minimal and rich media coupled with the evaluation of virulence factor production of P. aeruginosa in comparison to four other bacterial species (Pseudomonas putida, Pseudomonas fluorescens, Burkholderia cepacia, and Escherichia coli wild-type strains). Cellular growth and passing genetic information to the next generation depend on the synthesis of purines and pyrimidines, the precursors of DNA and RNA. The pyrimidine biosynthetic pathway is essential and found in most organisms, with the exception of a few parasites that depend upon the pyrimidine salvage pathway for growth. Both the pyrimidine biosynthetic and salvage enzymes are targets for chemotherapeutic agents. In our laboratory, research on pyrimidine auxotrophic mutants showed the role of the pyrimidine biosynthetic pathway and its intermediates on P. aeruginosa metabolism and impaired virulence factors production. The present research shows that pyrimidine enzymes are active in all phases of growth, …
Date: December 2005
Creator: Azad, Kamran Nikkhah
System: The UNT Digital Library

A Physiological Age-Grading System for Female Hydrellia pakistanae Deonier (Diptera: Ephydridae)

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Conflicting opinions about the effectiveness of H. pakistanae as a biological control agent for hydrilla prompt researchers to find a method for assessing the fly's success. Developing a physiological age-grading system for the fly using ovarian morphology to detect changes in reproductive activity is useful for evaluating reproductive status of the fly in field populations. Changes in the appearance of follicular relics in ovaries with oviposition provide a reliable method to estimate fecundity. Characteristics of follicular relics were used to develop a system with eight physiological age classes, three nulliparous and five parous. Changes that occur in the fat body were used to assist in classification of nulliparous females or those with low egg counts.
Date: December 2002
Creator: Lenz, Jennifer Marie
System: The UNT Digital Library

Comparative Morphology of Sensilla Styloconica on the Proboscis of North American Nymphalidae and Other Selected Taxa: Systematic and Ecological Considerations.

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Sensilla styloconica on the proboscis of 107 species of North American and tropical butterflies were comparatively studied using the scanning electron microscope. Focus was on 76 species of North American Nymphalidae representing 45 genera and 11 subfamilies. Nomenclature for generalized and specific types of nymphalid sensilla is proposed. Written descriptions and micrographs are presented for each species studied. Morphological features were generally consistent for all or most species within genera and sometimes within subfamilies, with specified exceptions. Statistical analysis revealed significant differences for six of eight variables tested between two distinct feeding guilds of North American Nymphalidae. Average number, density, extent of proboscis coverage with sensilla, their total length, and shoulder spine length were all significantly greater in the non-nectar feeding guild than in nectar feeders, and may indicate adaptation for greater efficiency in feeding on flat surfaces. The greater frequency of apical shoulder spines in non-nectar feeders may represent adaptation for protection of sensory pegs from mechanical abrasion during feeding, or for anchoring the flexible proboscis tip to the surface. Correlation analysis revealed 9 out of 28 positive correlations in nectar feeders and 5 out of 28 in non-nectar feeders. Results of preliminary cladistic analysis were not considered to …
Date: December 2001
Creator: Petr, Daniel
System: The UNT Digital Library

A laboratory course in experimental genetics for the biology major.

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This manual has been designed for a class of twenty- four students concurrently enrolled in the lecture course. The laboratory aids in the learning process and fosters an interest in the science of genetics. This manual and the experiments contained within are both informative and fun. The manual correlates with and expands upon the genetics course. Each investigation, with the exception of the Drosophila melanogaster project, can be completed in a 3-4 hour timeframe. This manual provides a “hands on” experience of theories simply discussed in the lecture course. This manual is intended to be a one-source manual where each investigation is designed to include an adequate introduction. Special attention has been given for each investigation with both the student and instructor in mind.
Date: December 2001
Creator: Lux, Melissa McNeil
System: The UNT Digital Library

A Novel Phytoestrogen that Acts as an Agonist for Human Estrogen Receptors.

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Estrogen is the natural agonist of the estrogen receptor (ER). However, certain plant-derived compounds or phytoestrogens have been identified that mimic estrogens and act as agonists and/or antagonists of ERs, depending on subtype and target tissue. Understanding how phytoestrogens interact with ERs, and therefore effect the estrogenic response, may prove beneficial in hormone replacement therapy and in the prevention and treatment of hormone-related diseases. Using Thin Layer Chromatography, gas chromatography/mass spectrometry (GC/MS), and proton nuclear nagnetic resonance (HNMR), I identified 4-ethoxymethylphenol (4EM) found in Maclura pomifera. While most phytoestrogens are heterocyclic compounds, 4EM is a simple phenol that acts as an agonist of ER-alpha and -beta in HeLa and MCF-7 cells. To study the effect of 4EM on ER-alpha and -beta activity, I performed transient transfection assays and showed that 4EM activates ER dependent gene transcription in a dose dependent manner in both ER subtypes. Further, 4EM- mediated transcription in ER-alpha, like estrogen, was enhance in the presense of co-activators, SRC-1 (steroid receptor coactivator-1), CBP (CREB binding proteins), and E6-AP (E6-associated protein) and inhibited by trans-4- hydroxytamoxifen (4HT). I found that 4EM was specific for ER and did not activate transcription of the progesterone receptor in HeLa cells.
Date: December 2001
Creator: Pearce, Virginia
System: The UNT Digital Library

Chemotactic Response of Lumbricus terrestris Coelomocytes to Larval and Adult Stages of Rhabditis pellio

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Experiments were performed to assess the suitability of Rhabditis pellio, a nematode found in earthworms, as a challenge organism for use in development of a biomarker assay to determine the potential of chemicals to suppress the immunocompetence of the non-specific immune system. To accomplish this goal, information on the life cycle of R. pellio was determined; including effects of incubation time and temperature on growth rates; along with information on the immune response elicited in the earthworm, Lumbricus terrestris. Immune parameters measured were coelomocyte migration toward and attachment to R. pellio larvae and adults. Preliminary background information showed that R. pellio has potential as a challenge organism for development of a biomarker assay.
Date: December 1999
Creator: Medrano, Jennifer Centurion
System: The UNT Digital Library