Natural and Social Sciences

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    Effects of ultraviolet radiation on the survival and metabolic and products of bacteroides melaninogenicus
    (1987-12) Smith-Kappus, Sheryl
    Bacteroides melaninogenicus was determined to be an aerotolerant anaerobic bacterial species. It was shown that exposure to atmospheric air for up to 90 min does not affect the viability of these microorganisms. A growth curve constructed for the organism showed that after a 4 h lag growth phase, B. melaninogenicus reached stationary growth phase in just 3 h. B. melaninogenicus was found to be more sensitive to chloramphenicol, metronidazole, and streptomycin than to any other antibiotic tested. Chloramphenicol, metronidazole, fluoroacetate, and caffeine, used in irradiation co-insult studies in this dissertation, were considered to be bacteriocidal and yet all allowed some cell viability even at the high superinhibitory concentrations tested. In experiments investigating DNA repair, it was shown that B. melaninogenicus does not repair UV light induced damage via photoreactivation. Survival curves constructed for the organism after exposure to UV light at 254 nm and 365 nm under aerobic and anaerobic conditions while the organisms were in exponential or stationary growth phase, revealed that the cells were most sensitive to UV induced damage when exposed to radiation while in the exponential growth phase under aerobic conditions at either wavelength. B. melaninogenicus exposed to UV light under anaerobic conditions while the cells were in stationary growth phase were much more sensitive to UV induced damage at 254 nm than cells irradiated under the same conditions at 365 nm UV. Survival studies of B. melaninogenicus after co-insult with UV light and subinhibitory concentrations of chloramphenicol, metronidazole, caffeine, or fluoroacetate, at 254 nm UV or 365 nm UV, under aerobic and anaerobic atmospheric conditions illustrated a decreased shoulder region on the curves, particularly after 365 nm UV exposure, when compared to UV irradiation applied without subsequent chemical treatment. The end products of the fermentation of glucose by B. melaninogenicus were affected after co-insult by UV and metronidazole, and UV and fluoroacetate. As expected, fluoroacetate treated cells produced less acetic acid, and in one mutant strain, SKF2r, small amounts of ethanol and methanol were produced. From the VPI strain, nine strains were isolated which produced altered metabolic end products from glucose; these mutants were named SKM1s, SKM2r, SKM3s, SKF1s, SKF2r, SKF3r, SKF4s, SKF5s, and SKF6s.
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    Morphological and histochemical observations of hepatic peroxisomes and lysosomes of rats after treatment with methylmercuric chloride, hydrogen peroxide and gamma radiation
    (1985-08) Chowdhury, Anisuzzaman
    The ultrastructure of cytochemically identified hepatic peroxisomes and lysosomes was studied at days 2, 7 and 21 following treatment with hydrogen peroxide (HP), methylmercuric chloride (MMC) and gamma radiation (I). The HP group received five daily intraperitoneal (IP) injections of 1.8 ml of 1.5% HP; the MMC group received a single IP injection of 6 mg MMC per kg body weight; the I group received 750 R whole body irradiation. Morphometric parameters were quantitated by stereological methods. The volume, surface and numerical densities on unbiased representative micrographs were estimated by point counting. The mean volume densities of hepatic peroxisomes of HP, MMC and I rats fell in the range of 0.94 (+OR-) 0.13 to 1.31 (+OR-) 0.14% of hepatocyte cytoplasm; surface densities ranged from 0.104 (+OR-) 0.013 to 0.127 (+OR-) 0.016 (mu)m('2)/(mu)m('3); numerical densities were in the range of 0.106 (+OR-) 0.013 to 0.128 (+OR-) 0.003 (mu)m('-3). The estimated mean volume densities of hepatic lysosomes of HP, MMC and I rats ranged from 0.45 (+OR-) 0.03 to 0.74 (+OR-) 0.04% of hepatocyte cytoplasm; mean surface densities ranged from 0.052 (+OR-) 0.002 to 0.077 (+OR-) 0.004 (mu)m('2)/(mu)m('3); mean numerical densities were in the range of 0.052 (+OR-) 0.004 to 0.070 (+OR-) 0.033 (mu)m('-3). None of the parameters showed any significant difference (P (LESSTHEQ) 0.05) between treated and control animals. Morphological observations revealed severe cytoplasmic degradation at day 2 after HP treatment which persisted to a moderate extent at day 7; no signs of toxic effect were observed at day 21. Livers of MMC treated rats demonstrated disruption of peroxisomal, lysosomal and mitochondrial membranes and formation of different shapes and sizes of peroxisomes at day 2. Damage appeared to be mild at day 7 and no apparent damage persisted until day 21. Following the whole body irradiation of 750 R, granularity in hepatic peroxisomes, accumulation of rough endoplasmic reticulum, loss of mitochondrial cristae and presence of polyribosomes and/or glycogen were observed at day 2. Seepage of hydrolytic enzymes from disrupted lysosomal membrane and persistence of polyribosomes or glycogen and dissolution of mitochondrial cristae were observed at day 7. Diffusion of reaction products from peroxisomes and apparent dissolution and peripheral movement of crystalline cores was observed at day 21 after irradiation.
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    The role of poly (adp-ribose) metabolism in cell survival following various forms of stress
    (1985-08) Smith, Janice; Jacobson, Elaine; Robert, P.; Kendrick, Michael
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    Modification of fecundity and fertility during oogenesis by gamma radiation and/or ozone with a cytological analysis in the ectoparasitic wasp, Habrobracon juglandis (Ashmead)
    (1984-05) Ofuoku, Edith; Erdman, Howard; Hupp, Eugene; Aboul-Ela, Mohamed; Fuerst, Robert; Schwalm, Fritz
    In Experiment I, adult female wasps were exposed to 44.1 ppm ozone for 0, 2, 4, 6, 8, 10, 12, 16, 24, and 27 h. The results indicated that the 27 h of ozone exposure produced 100% lethality on the first day. Exposures below 27 h progressively decreased life span with increasing length of exposure. In Experiment II A, adult virgin Habrobracon females were exposed to 44.1 ppm ozone for 0, 2, 4, 6, 8, 10, 12, 16, and 24 h to determine the effects of ozone on fecundity (egg laying ability) and fertility (egg hatching ability). The results showed that ozone significantly decreased fecundity and fertility in all meiotic stages except metaphase I. In Experiment II B, adult virgin Habrobracon females were exposed to 0, 25, 35, 45, and 65 Gy of Co-60 gamma radiation. All treated wasps showed significant progressive decreases in fecundity and fertility with increases in radiation dose; females given 45 and 65 Gy experienced temporary infecundity and permanent sterility, respectively. The results indicated the differential sensitivity of the various meiotic stages. In Experiment II C, adult virgin Habrobracon females were exposed to 0, 22.5, or 45 Gy of Co-60 gamma radiation; to 0, 8, or 16 h of 44.1 ppm ozone; or to combinations thereof to determine the effects of these insults on fecundity and fertility. Together or singly ozone and radiation reduced fecundity and fertility. The co-insult treatments resulted in additive or synergistic effects. In Experiment III, adult virgin Habrobracon females were exposed to the conditions of Experiment II C to correlate by cytological examination of the ovarioles the effects of ionizing radiation and/or ozone on the germ cells at specific meiotic stages. The ovarioles from females exposed to 8 and 16 h ozone had gaps in the series of developing reproductive units and these abnormalities increased with time. Radiation doses above 22.5 Gy caused destruction of germ cells and degeneration or atrophy of the ovarioles; while, the co-insult treatments resulted in more adverse effects on the ovarioles than the single insults. Results obtained from the cytological study explain the fecundity and fertility observations.
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    An In Vitro mammalian model for investigating locomotor pattern generation
    (1989-08) Hernandez, Patricia; Droge, Michael; Hines, John; Uphouse, Linda
    The goal of our research was to establish an in vitro mammalian spinal preparation suitable for investigating the mechanisms underlying motor pattern generation. The objective of the study was to compare the step cycle timing of intact, freely moving neonatal and adult Balb/C mice with the pattern generating capability of spinal cord-hindlimb explants taken from animals aged from birth to 4 days. The analysis was based on EMG recordings from the gastrocnemius (G) and tibialis anterior (TA) muscles, an antagonist set of muscles used in stepping. In intact animals, electrodes were placed in the G and TA muscles to ascertain the step cycle pattern and timing. Adult mice displayed reciprocal activation of the G and TA muscles and a faster cycle periods than the neonates. The neonates also exhibited reciprocal activation of the muscles, as well as asymmetrical activation and synchronous bursting. For the in vitro preparation, neonatal mice were anesthetized, electrodes were positioned into the G and TA muscles, and the spinal cord with the hindlimbs attached were surgically removed and perfused with ACSF. The spinal cord-hindlimb explant was investigated under 3 types of conditions: (1) nonhemisected spinal cord with Mg$\sp{++}$ present in the ACSF; (2) nonhemisected spinal cord without Mg$\sp{++}$ present in the ACSF; (3) hemisected spinal cord without Mg$\sp{++}$ in the ACSF. The pattern generating capability was first investigated spontaneously, and afterwards upon pharmacological stimulation with NMDA (an excitatory amino acid which is inhibited by Mg$\sp{++}$). Spontaneous bursting activity rarely occurred. In contrast, NMDA increased the occurrence of rhythmicity, especially in the absence of Mg$\sp{++}$. When rhythmic activity occurred spontaneously or was evoked by NMDA, rhythm was usually present in one muscle and faster step cycles were exhibited than in the intact neonate. There was a higher incidence of rhythmicity in the day 2 nonhemisected Mg$\sp{++}$ free explant. This preparation, with pharmacological stimulation, is useful for further investigation of motor pattern generation.
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    A spectrophotometric procedure for phytate determination
    (1980-12) Erwin, Kathy Jean; Wendel, Carlton; Barton, Janice; Stewart, George
    No abstract available
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    The status of the sociology of aging as evidenced in a content anlysis of the Journal of Gerontology and the Gerontologist
    (1978-12) Stern, Ruth Byers; Johansen, Elinor; Albert, Rodney; Davis, Ethelyn; Martin, Cora; McGeehon, Carol
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    The Federal Equal Rights Amendment as an issue in the Texas Legislature 1971-1975
    (1979-12) Ross, Charlotte Guinn; Yarborough, Kemp; Gilbert, Norma
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    Factors influencing the pattern of female lawlessness and contributing to the emergence of the violent female offender
    (1978-12) Jaber, Melinda Ann; Albert, Charles Rodney; Davis, Ethelyn; Gilbert, Norma
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    Marital satisfaction: A comparative study of black and white college students' attitudes toward marriage
    (1978-12) An, Judy Yi-Bii Li; Albert, Charles Rodney; Davis, Ethelyn; Johansen, Elinor; McGeehon, Carl; Malhotra, Valerie
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    World War II and Camp Howze: The impact upon Gainesville and Cooke County, Texas
    (1984-08) Burns, Barbara K.; Collins, Michael; Swain, Martha; Belfiglio, Valentine
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    "Fletcher Warren reporting for duty, sir. I have left all in order for my successor."
    (1986-08) Phillips, Mary Ann; DeMoss, Dorothy; Landry, Harral; Alexander, Jim
    The life story of Ambassador Fletcher Warren chronicles the evolution of an ordinary Texas farm boy of pioneer stock, who was among the first of his kind admitted to the Foreign Service, in his rise through the ranks to become privy to the nation's best-kept secrets. On two occasions Warren was a hero of no small dimension on the international scene, and also played an extraordinary role in national security. Warren's knowledge of Nicaraguan intrigue during the Thirties, together with his opinion of Anastasio Somoza and Augusto c. Sandino, provide a timely observation by which to appraise current events in Nicaragua.
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    Atomic fluorination of selected organic compounds
    (1978-12) Shariff, Syeda Ruqia; Sams, Lewis C.; Hamilton, Walter; Hurdis, Everett; Johnson, James; Mecay, William
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    Police officer: The person and the role an exploratory study of the extent to which the role affects the person
    (1979-12) Adams, E. R. (Rae) Banks; Albert, Rodney; Johansen, Elinor; McGeehon, Carl; Jolly, Virginia; Davis, Ethelyn