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AMP-activated protein kinase (AMPK) is a known regulator of whole-body energy homeostasis, but the downstream AMPK substrates mediating these effects are not entirely clear. AMPK inhibits fatty acid synthesis and promotes fatty acid oxidation by phosphorylation of acetyl-CoA carboxylase (ACC) 1 at Ser79 and ACC2 at Ser212. Using mice with Ser79Ala/Ser212Ala knock-in mutations (ACC DKI) we find that inhibition of ACC phosphorylation leads to reduced appetite in response to fasting or cold exposure. At sub-thermoneutral temperatures, ACC DKI mice maintain normal energy expenditure and thermogenesis, but fail to increase appetite and lose weight. We demonstrate that the ACC DKI phenotype can be mimicked in wild type mice using a ghrelin receptor antagonist and that ACC DKI mice have impaired orexigenic responses to ghrelin, indicating ACC DKI mice have a ghrelin signaling defect. These data suggest that therapeutic strategies aimed at inhibiting ACC phosphorylation may suppress appetite following metabolic stress

Efeito de flavonoides no eritrocito de individuos normais e portadores de anemia falciforme

Orientadores : Satie Hatsushika Ogo, Marcio Alberto TorsoniDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de BiologiaResumo: Espécies reativas de oxigênio (EROs) são constantemente formadas em células aeróbicas, particularmente nas mitocôndrias de células aeróbicas e nos eritrócitos. Estas EROs, em condições normais, são removidas por um eficiente sistema de detoxificação celular composto principalmente pelas enzimas antioxidantes, glutationa, vitaminas e microelementos. Entretanto, quando a produção de EROs sobrepõem a capacidade do sistema antioxidante, reações deletérias podem ocorrer caracterizando a condição conhecida como estresse oxidativo. Em algumas patologias, tais como anemia falciforme, talassemia e deficiência em glicose-6 fostato desidrogenase, o estresse oxidativo é ainda maior. A anemia falciforme é uma hemoglobinopatia genética caracterizada pelo aumento da geração de ERO, liberação anormal de ferro da Hb e atividade diminuída do sistema antioxidante gerando elevado estresse oxidativo. Diversas terapias têm sido utilizadas no intuito de minimizar os danos oxidativos sofridos por estes indivíduos portadores desta patologia, como a administração de ácido ascórbico e vitamina E. Neste trabalho o efeito de flavonóides, nos processos oxidativos do sangue de indivíduos portadores de anemia falciforme foi investigado. Os flavonóides são compostos amplamente distribuídos na natureza e por estarem presentes em grande quantidade na dieta humana podem ser ingeridos naturalmente; sua atividade antioxidante, antiosteoporótica, anticancerígena, antiinflamatória e antiviral têm sido bem descrita. O efeito dos flavonóides (quercetina e rutina) foi estudado nos processos de oxidação de Hb, ligação de Hb à membrana celular, peroxidação lipídica da membrana eritrocitária e formação de grupos carbonil de proteínas no sangue de indivíduos normais e portadores de anemia falciforme. Em geral, o nível de danos oxidativos encontrados no sangue de indivíduos falcêmicos foi maior do que no sangue de indivíduos normais, diferindo apenas nos experimentos de oxidação de Hb, nos quais os resultados foram semelhantes para ambas as Hb, este fato talvez se deva a presença de grande quantidade de Hb A, proveniente da transfusão, no sangue deStes pacientes. A quercetina mostrou maior efeito antioxidante em todos os experimentos. A rutina comportou-se como pró-oxidante na oxidação da Hb quando utilizada em concentrações inferiores a 150 _M, mostrando um efeito protetor acima desta concentração. Com base nos resultados obtidos, pode-se especificar que os flavonóides, principalmente a quercetina, apresentam um efeito benéfico na proteção contra os danos oxidativos do sangue de indivíduos portadores de anemia falciformeAbstract: Oxygen reactive species (ROS) are constantly formed in aerobic cells, particularly in the mithocondria and erythrocytes. These ROS, under normal conditions, are removed by an efficient antioxidant system composed by antioxidant enzymes, glutathione, vitamines and microelements. However, when the ROS production is higher than the antioxidant system capacity, pathological reactions can occur characterizing the oxidative stress condition. In some pathologies, such as sickle cell anaemia, thalassemia and glucose-6-phosphate desidrogenase deficience, the oxidative stress is increased. The sickle cell anaemia is a genetic disease characterized by an increase of ROS generation, abnormal iron release and lower antioxidant activity. Several therapies have been used in order to decrease the oxidative damages of these pacients, such as the acid ascorbic and vitamine E administration. Thus, it was interesting to investigate the effect of natural antioxidant compounds, the flavonoids, in oxidative processes in the blood of sickle cell anaemia individuais and to compare the results with of normal individuais. The flavonoids are compounds widely distributed in the nature and normaly consumed by humans since they are present in great amount in the human diet; their antioxidant, antiosteoporotic, antitumor, antinflamatory and antiviral activities have been described. The effect offlavonoids (quercetin and rutin) was studied in the process of Hb oxidation, binding of Hb to celular membrane, lipid peroxidation of erythrocyte membrane and protein carbonyl groups formation in the blood of sickle anaemia and normal individuais. In general, the oxidative damage levels found in the blood of sickle individuais were higher than that found in the blood of normal individuais, differing only in the experiments of Hb oxidation. In this case, the results were similar to both Hb, perhaps because of great amount of Hb A in the blood of sickle patients. The quercetin showed higher antioxidant effect in ali experiments. The rutin behaved as pro-oxidant in the Hb oxidation, when rutin is used in concentration lower than 150 11M, however it showed protective effect in higher concentrations. Supported by these results, we can suggest beneficial effects of flavonoids, mainly of quercetin, in the protection against oxidative damage of sickle anaemia individuais bloodMestradoBioquimicaMestre em Biologia Funcional e Molecula

Alumina synthesis by sol-gel method: characterization and application on epoxidations reactions

Orientador: Ulf Friedrich SchuchardtDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de QuimicaMestradoQuimica InorganicaMestre em Químic

Epoxidation Of Soybean Oil Catalysed By Ch3reo3/h2o2

The epoxidation of soybean oil with hydrogen peroxide catalysed by CH3ReO3 was investigated in order to evaluate the effect of nitrogen-containing bases (pyridine, 2-picoline, 3-picoline, 4-picoline, pyrazole and bipyridine N,N'-dioxide) on the activity and selectivity of the catalytic system. © 2000 Elsevier Science B.V. All rights reserved.130 B16611666Gustone, F.D., (1993) J. Am. Oil Chem. Soc., 70, p. 1139Al-AjIouni, A.M., Espenson, J.H., (1996) J. Org. Chem., 61, p. 3969Herrmann, W.A., Fischer, R.W., Rauch, M.U., Scherer, W., (1994) J. Mol. Catal., 86, p. 243Rudolp, J., Reddy, K.R., Chiang, J.P., Sharpless, K.B., (1997) J. Am. Chem. Soc., 119, p. 6189Wang, W., Espenson, J.H., (1998) J. Am. Chem. Soc., 120, p. 11335Herrmann, W.A., Ding, H., Kratzer, R.M., Kühn, F.E., Haider, J.J., Fischer, R.W., (1997) J. Organomet. Chem., 549, p. 319Nakajima, M., Sasaki, Y., Iwamoto, H., Hashimoto, S., (1998) Tetrahedron Lett., 39, p. 87Schuchardt, U., Lopes, O.C., (1988) J. Am. Oil Chem. Soc., 65, p. 1940Han, L.T., (1994) J. Am. Oil Chem. Soc., 71, p. 669Herrmann, W.A., Jratzer, R.M., Ding, H., Thiel, W.R., Glas, H., (1998) J. Org. Chem., 555, p. 29

t-BOOH-induced oxidative damage in sickle red blood cells and the role of flavonoids

Sickle cell anemia is a genetic disease characterized by an increase in generation of reactive oxygen species, abnormal iron release and low antioxidant activity which can lead to cell injury. Several therapies have been used to decrease the oxidative damage in these patients. In this study, we investigated the effect of flavonoids (quercetin and rutin) on the oxidation of red blood cells (RBC) from sickle cell anemia patients following exposure of the cells to tert-butyl hydroperoxide (t-BOOH). Quercetin provided greater protection against Hb oxidation, the binding of Hb to membrane and lipid peroxidation than did rutin. Quercetin (150 muM) reduced Hb oxidation by 30% and increased the level of oxyHb from 17.5 to 29 muM. Rutin prevented Hb oxidation only at concentrations higher than 200 muM and did not prevent the binding of Hb to RBC membrane. These distinct effects of the flavonoids probably reflect their structural characteristics. Thus, quercetin, which possesses a suitable structure for free-radical scavenging and ion quelation, was a more effective antioxidant than rutin. The presence of rutinose at position C-3 in rutin may impair its antioxidant effect. The presence of ascorbic acid enhanced the protective effect of quercetin and rutin against oxidative stress in sickle Hb and lipid peroxidation. This synergistic action helped to maintain a constant supply of flavonoids and thus, rescue the cells from the injury caused by free radicals and iron ions. (C) 2003 Editions scientifiques et medicales Elsevier SAS. All rights reserved.574173212412

Effect of thiol reagents on functional properties and heme oxidation in the hemoglobin of Geochelone carbonaria

The reaction of thiol reagents with G. carbonaria hemoglobin was studied, and the oxygen equilibrium and kinetic of oxidation of derivatives determined. The oxygen affinity and kinetic of oxidation of hemoglobin derivatives were modified to various extents depending on the nature of thiol reagents used. Diamide yielded approximately 80% polymeric hemoglobin, although the oxidation kinetic, and the functional properties, were practically invariant (T-1/2 =10.0 min.; P50 = 5.0 mm Hg at pH 7.4; alkaline Bohr effect = -0.64). Iodoacetamide did not modify the electrophoretic pattern significantly, although all the free SH groups of hemoglobin were alkylated. A P50 of 2.5 mmHg at pH 7.4 and the Bohr effect of -0.15 were obtained; the T-1/2 Of about 6.4 min. was shorter than that for un-modified Hb. Similar T-1/2 were obtained for Hb treated with oxidized glutathione, which produced polymeric Hb and glutathionyl-Hb. The oxygen binding characteristics showed that both of Hb derivatives, glutathionyl-Hb and polymeric Hb, maintain the capacity to transport the gas.40235536

Alumina-Catalyzed Epoxidation with Hydrogen Peroxide: Recycling Experiments and Activity of Sol-Gel Alumina

Commercial alumina looses some activity after the first epoxidation reaction of (S)-limonene with hydrogen peroxide, but maintains a good activity and a very high selectivity in the subsequent three reactions. After this its activity is strongly reduced, probably due to structural modifications. Aluminas obtained by sol-gel methods are normally less active than the commercial alumina. However, the use of monomeric aluminum sec-butoxide and of oxalic acid to form stable alumina mesophases allows a very active alumina to be obtained, which catalyses the epoxidation of the less reactive cyclohexene with hydrogen peroxide in 98% yield. Close to 50% of the active oxygen is used up in the formation of molecular oxygen