Thesis (M.Sc.)--University of Alberta, 2010. / A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Master of Science in Physiology. Title from pdf file main screen (viewed on February 16, 2010). Includes bibliographical references.

Thesis (Ph. D.)--Ohio State University, 2009. / Title from first page of PDF file. Includes vita. Includes bibliographical references (p. 112-122).

Diss. (sammanfattning) Umeå : Sveriges lantbruksuniversitet, 2009. / Härtill 4 uppsatser.

Thesis (D.A.)--University of Delaware, 2010. / Principal faculty advisor: Charles G. Riordan, Dept. of Chemistry & Biochemistry. Includes bibliographical references.

Thesis (Ph. D.)--University of Washington, 2005. / Vita. Includes bibliographical references (leaves 155-168).

Thesis (Ph.D.) OGI School of Science & Engineering at OHSU, October 2007. / Includes bibliographical references (leaves 132-158).

Thesis (MTech (Biomedical Technology))--Cape Peninsula University of Technology, 2006 / Cells living under aerobic conditions constantly face the oxygen paradox i.e. oxygen is indispensable for supporting life; however, its metabolites such as reactive oxygen species (ROS) can modify cell function. Oxidative stress (OS) arises as a consequence of excessive ROS production and/or impaired antioxidant defence mechanisms. Environmental and physiological factors have been implicated in poor sperm function. Excessive ROS generation results in oxidative damage and consequently decreased sperm function. The objectives of this study are threefold: (i) To measure the production of O 2 -. by sperm by means of flow cytometry. (ii) To determine effects of O2 -. on sperm motility and viability in the presence or absence of commercially available scavengers and RPO. (iii) To determine effects of O2 -. on selective apoptotic markers in ejaculated sperm in the presence of absence of commercially available scavengers and RPO. In the first part of the study, suitable solvents were investigated in order to introduce RPO (because of its hydrophobic nature) as a possible scavenger of ROS in human spermatozoa. Secondly, the O2 -. donor; 2, 3-dimetoxy-1-naphthoquinone (DMNQ) (2.5~M-100~M, 60 min.) was added to normozoospermic post swim-up samples in the absence or presence of Mn(lIl)TMPyP (50~M) or SOD (501U) or RPO at 0.1% and 0.5%. CASA was used to analyse motility parameters, while FACS was used to determine viability (PI, 1mM, 15 min.) and O2 -. levels (DHE, 30~M, 15min.).

O objetivo do estudo foi estimar a biodisponibilidade de duas fontes de cobre: orgânica (cobre metionina) e inorgânica (sulfato de cobre) na dieta de cordeiros. O experimento foi conduzindo na FZEA USP de Pirassununga utilizando 40 cordeiros da raça Merino X Texel, que foram distribuídos aleatoriamente em cinco grupos, e submetidos a cinco tratamentos, totalizando oito animais por tratamento: Tratamento 0: Dieta controle sem adição de Cu; Tratamento 1: 10 mg de Cu/Kg de MS na forma de sulfato de Cu; Tratamento 2: 30g de Cu/Kg de MS na forma de sulfato de Cu; Tratamento 3: 10 mg de cu/kg de MS na forma de cobre metionina; Tratamento 4: 30 mg de cu/kg de MS na forma de cobre metionina. Foram feitas biópsias do fígado dos animais no tempo zero para análise de cobre e colhidas amostras de sangue nos dias 0, 28, 56 e 84 dias para determinação de Cu sérico, atividade de ceruloplasmina e enzimas de função hepática. Ao final do experimento, os animais foram abatidos para colheita de amostras de fígado, músculo e rim, para determinação dos teores de Cu e da enzima superóxido dismutase (SOD). Nos últimos dez dias do experimento foi realizado um balanço metabólico de cobre. A biodisponibilidade foi calculada pela técnica \"slope ratio\", utilizando como parâmetros a concentração de cobre no fígado. Não houve diferença (P>0,05) no desempenho dos animais (peso vivo e ganho de peso) entre os tratamentos. A concentração sérica de AST e ALT permaneceu abaixo dos níveis de intoxicação em todos os tratamentos, durante todo o período. A atividade da ceruloplasmina não diferiu entre os tratamentos (P>0,05). O teor de cobre no soro, na biópsia do fígado e no músculo não foi diferente (P>0,05) entre os tratamentos. Entretanto, a concentração do mineral no fígado dos animais suplementados (284,28 mg/kg) foi maior (P<0,05), quando comparados ao grupo controle (168,01 mg/kg), assim como o Cu-met 30 mg/kg (341,29 mg/kg) foi superior (P<0,05) ao de 10mg/kg MS (263,02 mg/kg). A atividade da SOD nos animais suplementados (µmol/mg prot foi superior à do grupo controle. Nos rins o teor de cobre foi superior nos animais que receberam 30mg/kg de MS de Cu-met (6,65 mg/kg) em relação aos que receberam 10 mg/kg de MS da mesma fonte (3,86 mg/kg). A absorção e a retenção aparentes do cobre foram maiores para a fonte inorgânica, comparada com a orgânica. A biodisponibilidade do cobre determinada pela concentração de cobre no fígado, utilizando a técnica do \"slope ratio\", considerando o CuSO4 como padrão (100%), apresentou disponibilidade de 150,64% para o Cu-met. / The study was conducted to estimate the relative bioavailability of two sources of supplemental copper: organic (copper methionine) and inorganic (copper sulfate) in the diet of lambs, by analyzing the concentration of copper and enzymes in the liver and metabolic balance calculation, using 40 lambs breed Merino X Texel, which was fed three concentrations of copper (basal + two additions) in two sources, which were randomly allotted to five groups, and subjected to five treatments: treatment 0: control (diet without addition of Cu); treatment 1: (diet with 10 mg Cu/Kg DM of CuSO4); Treatment 2: (diet with 30 g Cu/Kg DM of CuSO4); Treatment 3: (diet with 10 mg Cu/kg DM of copper methionine; Treatment 4: (diet with 30 mg cu/kg DM of copper methionine). Liver biopsies were made on 0 d. Blood samples were taken via the jugular vein on 0, 28, 56 and 84 d to determine serum Cu and serum ceruloplasmin and liver transaminases (AST, ALT) concentrations. The animals were slaughtered and samples of liver, kidney and muscle were taken for the determination of the levels of Cu and superoxide dismutase activity. In the last ten days of the experiment a metabolic balance of copper was conducted. The bioavailability was calculated by the \"slope ratio\" technique, using the concentration of copper in the liver as parameter. There was no difference (P >0.05) on animal performance (live weight and weight gain) among treatments. The serum AST and ALT levels remained below poisoning in all treatments during the period. The ceruloplasmin activity did not differ between treatments (P>0.05). The copper content in biopsy, serum and muscle was not different (P>0.05) between treatments. However, the mineral concentration in the liver of animals fed (284.28 mg/kg) was higher (P <0.05) when compared to the control group (168.01 mg/kg ) and 30 Cu -met mg/kg (341.29 mg/kg) was higher (P <0.05) at 10mg/kg MS (263.02 mg/kg). The SOD activity in the supplemented animals (mmol/mg prot) was superior to the control group. Copper in Kidneys was higher in animals that received 30mg/kg MS meth-Cu (6.65mg/kg) compared those receiving 10 mg/kg DM from the same source (3.86 mg/kg). Apparent absorption and retention of copper were higher for inorganic source, compared with the organic. The bioavailability determined by the concentration of copper in the copper liver, using the technique of \"slope ratio\", considering CuSO4 as standard ( 100% ) presented availability of 150.64 % for Cu-met.

>Magister Scientiae - MSc / Nitric oxide (NO) is a signaling molecule involved in mediating plant responses to various biotic and abiotic stresses. Major abiotic stresses (drought, salinity, cold) induce common cellular responses, causing osmotic stress in plants. This results in oxidative stress due to increased production of reactive oxygen species (ROS). The increased ROS levels simultaneously induce the antioxidative system (including antioxidant enzymes such as superoxide dismutase) that regulates ROS toxicity and enhance stress tolerance in plants. It is suggested that the scavenging of ROS by antioxidant enzymes can be controlled by NO. The aim of this study was to evaluate the role of exogenously applied NO on soybean (Glycine max L. Merr.) during osmotic stress, with the purpose of determining the effects of NO on the superoxide dismutase (SOD) activity in response to osmotic stress. This study also aimed at identifying and characterising SOD isoforms induced in soybean in response to osmotic stress and exogenous NO. To achieve these aims, soybean plants were treated with sorbitol (to induce osmotic stress), an NO donor [2,2'-(hydroxynitrosohydrazono)bis-ethanimine, DETA/NO] and its respective control (Diethylenetriamine, DETA). The results showed that exogenous NO alleviated osmotic stress-induced damage by reducing the superoxide radical content, lipid peroxidation levels and also maintaining cell viability in soybean leaves, nodules and roots. Only two SOD isoforms i.e. manganese SOD (MnSOD) and copper/zinc SOD (CuZnSOD) were identified and characterised in soybean leaves and roots, iron SOD (FeSOD) was not induced. The isoforms identified exhibited low SOD activity in response to osmotic stress, with the exception of a few isoforms that had increased activity. The SOD activity was regulated by exogenously applied NO. The enzymatic activity of SOD isoforms was up-regulated by exogenous NO, except for a few SOD isoforms that were not responsive to NO. The results also showed that the increased SOD activity was associated with reduced lipid peroxidation levels. The results obtained from this study suggest that exogenous NO improves osmotic stress tolerance in soybean by regulating and increasing the SOD activity of only specific isoforms. The increased SOD activity maintains the redox homeostasis balance by detoxifying and controlling the superoxide radical levels, subsequently reducing lipid peroxidation and maintaining cell viability.

It has long been known that oxygen has the potential to be toxic to biologic systems and that this toxicity is not due to oxygen itself, but due to the production of oxygen radicals. One of these potentially toxic radicals, superoxide (O₂⁻) can be generated as a result of ionizing radiation, and if not adequately removed can proceed to cause cell damage. Superoxide dismutase (SOD) is one of the key enzymes involved in the defence against oxygen toxicity. SOD activity can be inhibited by diethyldithiocarbamate (DOC), a powerful copper chelator. If inhibition of SOD by DOC increases the lifetime and effectiveness of radiation induced O₂⁻, it follows that the potential exists for DOC to enhance the effect of radiation. DOC is however also a thiol compound, and thus may act as a radioprotector by modifying tissue oxygenation status or by free radical scavenging. This study has concerned itself primarily with the inhibition of superoxide dismutase by diethyldithiocarbamate in order to sensitize tumours to ionizing radiation. The use of DOC as an inhibitor of SOD has however meant that any sensitization resulting from SOD inhibition could be masked by a radioprotective effect by DOC. The inhibition of SOD by DDC was confirmed in a murine rhabdomyosarcoma, and it was shown that this inhibition can be maintained for up to twenty-four hours after DDC administration. It was hypothesised that there was a potential for the radioprotective effect of DDC to be overcome, if the levels of DDC were low enough at the time of irradiation. Indeed, if DDC was removed from the growth medium of B16 mouse melanoma cells in culture prior to irradiation, a significant sensitization was demonstrated. It was shown that DDC could act as both a radiosensitizer and as a radioprotector in the same experiment. The dominant action of DDC was found to be dependent on the time allowed between DDC administration and irradiation. If this time was approximately 4 hours, it was possible to show a radiosensitizing effect by means of a tumour growth delay assay. This time modulation effect of DOC was shown in larger tumours, rather than smaller tumours, which could indicate that tumour oxygenation is an important criterion in determining the response to radiation of DOC treated cells. It was shown that B16 mouse melanoma cells exposed to 43°C after DDC pre-treatment were sensitized to thermal damage. This work suggests that some caution should be exercised when DDC is put forward as either a radiosensitizer or a radioprotector in the clinic, but that DDC may have potential as a thermosensitizer.