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

Orientador: Ana Cláudia de Melo Stevanato Nakamune / Banca: Camila Renata Corrêa Camacho / Banca: Paulo Cesar Ciarlini / Resumo: A doxorrubicina (DXO) é eficaz contra diferentes formas de câncer, em adultos e crianças, porém seu uso pode causar cardiotoxicidade aguda e crônica, associada ao aumento do estresse oxidativo. Alguns antioxidantes naturais demonstraram ser eficazes em minimizar esses efeitos da DXO, no entanto, o chá mate (CM), não foi avaliado neste contexto. Nossa hipótese é que o pré-tratamento com CM por 30 dias, reduz o dano oxidativo agudo no coração e assim preserva a função cardíaca. Para testar essa hipótese, foram investigados os efeitos do pré-tratamento diário de ratos Wistar machos com 40 mg/kg m.c. de CM, contra a cardiotoxicidade aguda induzida por DXO. Para a escolha da dose de CM ratos Wistar foram divididos em grupo tratados com doses diferentes de chá (10, 20 e 40 mg/m.c., gavagem) e DXO (grupos CM + DXO). Os grupos controle (C), tratados com DXO (DXO) receberam água (1,0 mL, gavagem). Os grupos receberam CM solúvel diluído em água (8 mg/mL). No 29° do tratamento com CM, administrou-se uma dose de DXO (15 mg/kg m.c. - IP) aos grupos DXO e CM + DXO. No 31° dia, após administração de tiopental (50 mg/kg m.c.) associado à lidocaína (4,0 mg/kg m.c.), foram submetidos ao eletrocardiograma (ECG) antes da punção cardíaca (Autorização CEUA FOA: 416/2015). Creatina quinase total (CK) e a fração MB (CK-MB), foram estimadas no plasma. No homogenato de coração (KCl 1,15% m/v) foram quantificadas as substâncias reativas ao ácido tiobarbitúrico (TBARS), glutationa (GSH), atividade de su... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Doxorubicin (DXO) is effective against different forms of cancer in adults and children, but its use may cause acute and chronic cardiotoxicity associated with increased oxidative stress. Some natural antioxidants have been shown to be effective in minimizing the effects of DXO; however, mate tea (CM), has not been evaluated in this context. Our hypothesis is that CM pretreatment for 30 days, reduces acute oxidative damage in the heart. To test this hypothesis, the effects of daily pretreatment of male Wistar rats at 40 mg / kg m.c. of CM, against acute cardiotoxicity induced by DXO were investigated. For the choice of CM dose, Wistar rats were divided into groups treated with different doses of tea (10, 20 and 40 mg / mc, gavage) (CM + DXO groups). Groups control (C), treated with DXO (DXO) received water (1.0 mL, gavage). The CM + DXO groups received soluble CM diluted in water (8 mg / mL) during the same period. At 29 ° of CM treatment, DXO and CM + DXO groups were given a dose of DXO (15 mg / m.c.-IP). On the 31st day, after administration of lidocaine (4.0 mg / kg mc) thiopental (50 mg / kg mc), all rats were submitted to electrocardiogram (ECG) prior to cardiac puncture (CEUA FOA Authorization: 416 / 2015). Total creatine kinase (CK) and MB fraction (CK-MB) were estimated in plasma. The thiobarbituric acid reactive substances (TBARS), glutathione (GSH), total superoxide dismutase (SOD) activity and the cytoplasmic isoform SOD1, in addition to SOD1 expression, were quantified in the heart homogenate (KCl 1.15% m / v), Total Akt and p-Akt, by western blotting. Pretreatment with 40 mg / kg m.c. of CM prevented a increased heart rate, prolongation of the QTc and PR interval, increase in plasma CK and CK-MB, and TBARS in the tissue. It also prevented the reduction of GSH, SOD and SOD1. In addition, the increase... / Mestre

Submitted by Ramon Santana (ramon.souza@ufpe.br) on 2015-03-11T14:49:23Z No. of bitstreams: 2 TESE Cybelle Façanha Barreto Medeiros Linard.pdf: 2166817 bytes, checksum: af13a7a07c81d5fdab1831019d105d01 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) / Made available in DSpace on 2015-03-11T14:49:23Z (GMT). No. of bitstreams: 2 TESE Cybelle Façanha Barreto Medeiros Linard.pdf: 2166817 bytes, checksum: af13a7a07c81d5fdab1831019d105d01 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Previous issue date: 2014-10-30 / FACEPE (Fundação de Amparo à Ciência e Tecnologia do Estado de Pernambuco) CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico) / O aumento da população idosa tem levado a uma crescente incidência de doenças neurodegenerativas em todo o mundo. O consumo de alimentos de origem vegetal e o uso das propriedades terapêuticas de muitas plantas destacam-se desde os primórdios da humanidade. Anacardium occidentale Linn, conhecido popularmente como cajueiro, é uma árvore nativa do Norte e Nordeste do Brasil. Seu pseudofruto possui elevado teor de vitamina A, do complexo B, C e compostos fenólicos. O ácido anacárdico, composto fenólico obtido a partir do Anacardium occidentale, possui propriedades terapêuticas tais como: antimicrobiana, gastroprotetora, anticarcinogênica e anti-inflamatória. Evidências in vitro e in vivo mostraram que tanto o Anacardium occidentale quanto o ácido anacárdico possuem baixa toxicidade e efeitos antioxidantes, sugerindo potencial uso terapêutico. Entretanto, nenhum desses estudos foi realizado para testar o efeito antioxidante da administração sistêmica do Anacardium occidentale e ácido anacárdico no sistema nervoso central em modelo experimental de doença de Parkinson. Neste estudo hipotetizamos que Anacardium occidentale e ácido anacárdico podem exercer neuroproteção no córtex cerebral e no sistema nigroestriatal contra o estresse oxidativo induzido pela rotenona. Ratos adultos foram tratados por via oral com extrato hidroetanólico de Anacardium occidentale (150 e 600 mg/kg), ácido anacárdico (1-100 mg/kg) ou veículo, 1 hora antes da administração de rotenona (3 mg/kg) por via subcutânea durante 5 dias consecutivos. O comportamento dos animais foi avaliado nos testes do campo aberto, rotarod, catatonia e labirinto em T. Os sinais de neurodegeneração na substância negra, lipoperoxidação no sistema nigroestriatal e córtex cerebral e dosagem da enzima superóxido dismutase total também foram avaliados. Os grupos tratados com Anacardium occidentale e ácido anacárdico melhoraram a neuromotricidade nos testes comportamentais e, nas doses de 150 e 600 mg/kg de Anacardium occidentale no córtex, diminuíram a lipoperoxidação, provocados pela rotenona, em 47 e 62%, respectivamente; no estriado, em 32 e 56%, respectivamente; e na substância negra, na dose de 600 mg/kg, em 76%. O aumento da atividade da enzima superóxido dismutase total foi detectada usando ácido anacárdico 25-100 mg/kg em todas as regiões analisadas. Este aumento variou de acordo com a região, correspondendo a cerca de 80% na substância negra, 53% no córtex cerebral e de 230% no corpo estriado. O ácido anacárdico também diminuiu sinais de neurodegeneração provocados pela rotenona na substância negra. A administração oral de Anacardium occidentale e ácido anacárdico impediram a neurotoxicidade induzida pela rotenona em ratos, em parte, devido à sua ação moduladora sobre a enzima superóxido dismutase total, reduzindo neurodegeneração no sistema nigroestriatal e no córtex cerebral.

Submitted by Helena Bejio (helena.bejio@unioeste.br) on 2017-11-22T18:59:05Z No. of bitstreams: 2 Daiana LB Franca 2016.pdf: 861200 bytes, checksum: 32ce3c922ac5969d272d83b1d94ae315 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-11-22T18:59:05Z (GMT). No. of bitstreams: 2 Daiana LB Franca 2016.pdf: 861200 bytes, checksum: 32ce3c922ac5969d272d83b1d94ae315 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2016-12-15 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Ethanol has been studied as an inhibitor of ethylene biosynthesis, which can be of great benefit for the post-harvest conservation of fruits. However, studies have shown that some climacteric fruits, such as banana, did not respond to ethanol. The ability of the banana to absorb ethanol may be limited and interfere with its ethylene regulatory action. The objective of this work was to evaluate the effect of exposure time and ethanol dose on ethylene production, respiration, antioxidant enzymes and postharvest preservation of 'Prata' banana. A first sample of bananas was exposed to ethanol vapor (100 μL) for 10.0 hours. Another sample of bananas was exposed to 50, 100 and 150 μL of ethanol and then stored for 12 days. Respiratory rate, ethylene production, activities of the enzymes superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), phenylalanine ammoniumase (FAL) and polyphenoloxidase (PPO), physicochemical characteristics and degradation were evaluated. The respiration rate and ethylene production of ethanol treated bananas (71.13 mg CO2 kg-1 h-1 and 0.009 μg C2H4 kg-1 h-1, respectively) were lower than the control fruits (101.58 mg kg -1 h -1 and 0.014 μg kg -1 h -1, respectively), but this occurred only with 4 hours of exposure to ethanol, during which time there was a peak of ethanol uptake in the fruit. Ethanol caused higher SOD and CAT activity and less APX activity of banana bark only in the first two hours of exposure, but this was not related to ethylene production or respiratory rate. Ethanol influenced changes in PPO and FAL activities after the peak of its maximum absorption by the fruit (4 hours). During storage, ethanol caused a decrease in the ethylene production of the fruits, but there was no effect of the doses. Ethanol did not influence the respiratory rate, sugar conversion, texture and loss of fresh banana mass during storage. This study showed that ethanol has an effect on the metabolism of ethylene, but that this has no reflection on some quality parameters of 'Prata' banana. On the other hand, ethanol was able to delay the degradation of the fruit, and this is commercially advantageous. / O etanol tem sido estudado como um inibidor da biossíntese de etileno, o que pode ser de grande benefício para a conservação pós-colheita de frutos. Entretanto, estudos mostraram que alguns frutos climatéricos, como a banana, não mostraram resposta ao etanol. A capacidade da banana em absorver etanol pode ser limitada e interferir na sua ação reguladora do etileno. O objetivo deste trabalho foi avaliar o efeito do tempo de exposição e da dose de etanol sobre a produção de etileno, respiração, enzimas antioxidantes e conservação pós-colheita da banana ‘Prata’. Uma primeira amostra de bananas foi exposta ao vapor de etanol (100 µL) por 10,0 horas. Outra amostra de bananas foi exposta a 50, 100 e 150 µL de etanol e depois foi armazenada por 12 dias. A taxa respiratória, produção de etileno, atividades das enzimas superóxido dismutase (SOD), catalase (CAT), ascorbato peroxidase (APX), fenilalanina amonialiase (FAL) e polifenoloxidase (PPO), características físicoquímicas e degradação, foram avaliadas. A taxa respiratória e a produção de etileno das bananas tratadas com etanol (71,13 mg CO2 kg-1 h-1 e 0,009 µg C2H4 kg-1 h-1, respectivamente) foram inferiores aos frutos do controle (101,58 mg kg-1 h-1 e 0,014 µg kg-1 h-1, respectivamente), mas isso ocorreu apenas com 4 horas de exposição ao etanol, período no qual houve um pico de absorção de etanol no fruto. O etanol causou maior atividade de SOD e CAT e menor atividade da APX da casca das bananas apenas nas duas primeiras horas de exposição, mas isso não esteve relacionado com a produção de etileno ou taxa respiratória. O etanol influenciou mudanças nas atividades de PPO e FAL após o pico de sua máxima absorção pelo fruto (4 horas). Durante o armazenamento, o etanol causou diminuição da produção de etileno dos frutos, mas não houve efeito das doses. O etanol não influenciou a taxa respiratória, a conversão de açúcares, a textura e a perda de massa fresca da banana durante o armazenamento. Este estudo mostrou que o etanol tem efeito sobre o metabolismo do etileno, mas que isso não tem reflexo sobre alguns parâmetros de qualidade da banana ‘Prata’. Por outro lado, o etanol foi capaz de atrasar a degradação do fruto, e isso é vantajoso comercialmente.

>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.

Corals are critical to marine biodiversity and human welfare. Coral reefs cover <1% of the seafloor but support ~1/3 of all marine species. Approximately 1.5 billion people live within 100 km of coral reefs, relying upon them for food, income from tourism, and protection from storms. Their economic value has been estimated at $375 billion annually. The foundation of coral reefs is the intracellular symbiosis between corals and photosynthetic dinoflagellates of the family Symbiodiniaceae. Tropical corals satisfy up to 95% of their nutritional requirements through photosynthesis, and their ability to construct reefs is biochemically coupled to photosynthesis. While permitting corals to thrive, photosymbiosis also increases their exposure to environmental stressors and vulnerability to climate change. Reliance on photosynthesis restricts reef-building corals to shallow, clear, tropical waters, where they experience higher temperatures and UV exposure. The generation of reactive oxygen species by the symbiont also exposes corals to greater oxidative stress. The symbiosis is particularly sensitive to climate change: all of the mass coral bleaching events have occurred since 1982, driven by elevated ocean temperatures. Molecular cross-talk between host and symbiont impacts resilience of the coral holobiont and resistance to bleaching. Unfortunately, we know little about how photosymbiosis impacts expression or activity of coral genes. Tropical corals engage in an obligate symbiosis with Symbiodiniaceae, so we cannot study their gene expression in a stable aposymbiotic state. However, the northern star coral, Astrangia poculata, engages in a facultative symbiosis with Symbiodiniaceae. I used RNA sequencing to investigate how symbiosis impacts gene expression in A. poculata, focusing on genes implicated in photosymbiosis: antioxidant enzymes (specifically superoxide dismutases) and the NF-κB signaling pathway. From an improved transcriptome assembly, I recovered core elements of a primitively simple NF-κB signaling pathway and a rich complement of SOD proteins. 273 coral transcripts—many associated with protein metabolism and vesicle-mediated transport— were differentially expressed in symbiotic versus aposymbiotic corals. Unlike in the facultatively symbiotic sea anemone Exaiptasia, symbiosis was not associated with depressed NF-κB transcript levels. IKKε, a potential positive regulator of NF-κB activity, was strongly up-regulated, as was one particular superoxide dismutase.

Generation of free radicals upon reperfusion has been cited as one of the major causes of ischaemia/reperfusion injury. The following series of experiments was designed to study the effect of manganese superoxide dismutase (MnSOD) overexpression in transgenic mice on ischemia/reperfusion injury. A species of 1.4 kb human MnSOD mRNA was expressed, and a 325% increase in MnSOD activity was detected in the hearts of transgenic mice with no changes in the other antioxidant enzymes or heat shock proteins. Immunocytochemical study indicated an increased labeling of MnSOD mainly in the heart mitochondria of the transgenic mice. When these hearts were perfused as Langendorff preparations for 45 min after 35 min of global ischemia, the functional recovery of the hearts, expressed as heart rate x left ventricular developed pressure, was 52 ± 4% in the transgenic hearts as compared to 31 ± 4% in the non-transgenic hearts. This protection was accompanied by a significant decrease in lactate dehydrogenase release from the transgenic hearts. Overexpression of MnSOD limited the infarct size in vivo in a left coronary artery ligation model. Our results demonstrate that overexpression of MnSOD renders the heart more resistant to ischemia/reperfusion injury.