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Scatena, Roberto,Messana, Irene,Martorana, Giuseppe Ettore,Gozzo, Maria Luisa,Lippa, Silvio,Maccaglia, Alessandro,Bottoni, Patrizia,Vincenzoni, Federica,Nocca, Giuseppina,Castagnola, Massimo,Giardina, Korean Society for Biochemistry and Molecular Biol 2004 Journal of biochemistry and molecular biology Vol.37 No.4
Experimental hyperoxia represents a suitable in vitro model to study some pathogenic mechanisms related to oxidative stress. Moreover, it allows the investigation of the molecular pathophysiology underlying oxygen therapy and toxicity. In this study, a modified experimental set up was adopted to accomplish a model of moderate hyperoxia (50% $O_2$, 96 h culture) to induce oxidative stress in the human leukemia cell line, U-937. Spectrophotometric measurements of mitochondrial respiratory enzyme activities, NMR spectroscopy of culture media, determination of antioxidant enzyme activities, and cell proliferation and differentiation assays were performed. The data showed that moderate hyperoxia in this myeloid cell line causes: i) intriguing alterations in the mitochondrial activities at the levels of succinate dehydrogenase and succinate-cytochrome c reductase; ii) induction of metabolic compensatory adaptations, with significant shift to glycolysis; iii) induction of different antioxidant enzyme activities; iv) significant cell growth inhibition and v) no significant apoptosis. This work will permit better characterization the mitochondrial damage induced by hyperoxia. In particular, the data showed a large increase in the succinate cytochrome c reductase activity, which could be a fundamental pathogenic mechanism at the basis of oxygen toxicity.
( Roberto Scatena ),( Irene Messana ),( Giuseppe Ettore Martorana ),( Maria Luisa Gozzo ),( Silvio Lippa ),( Alessandro Maccaglia ),( Patrizia Bottoni ),( Federica Vincenzoni ),( Giuseppina Nocca ),( 생화학분자생물학회 2004 BMB Reports Vol.37 No.4
Experimental hyperoxia represents a suitable in vitro model to study some pathogenic mechanisms related to oxidative stress. Moreover, it allows the investigation of the molecular pathophysiology underlying oxygen therapy and toxicity. In this study, a modified experimental set up was adopted to accomplish a model of moderate hyperoxia (50% 0₂, 96 h culture) to induce oxidative stress in the human leukemia cell line, U-937. Spectrophotometric measurements of mitochondria) respiratory enzyme activities, NMR spectroscopy of culture media, determination of antioxidant enzyme activities, and cell proliferation and differentiation assays were performed. The data showed that moderate hyperoxia in this myeloid cell line causes: i) intriguing alterations in the mitochondria) activities at the levels of succinate dehydrogenase and succinate-cytochrome c reductase; ⅱ) induction of metabolic compensatory adaptations, with significant shift to glycolysis; ⅲ) induction of different antioxidant enzyme activities; ⅳ) significant cell growth inhibition and ⅴ) no significant apoptosis. This work will permit better characterization the mitochondrial damage induced by hyperoxia. In particular, the data showed a large increase in the succinate cytochrome c reductase activity, which could be a fundamental pathogenic mechanism at the basis of oxygen toxicity.
Giant magneto-elastic coupling in multiferroic hexagonal manganites
Lee, Seongsu,Pirogov, A.,Kang, Misun,Jang, Kwang-Hyun,Yonemura, M.,Kamiyama, T.,Cheong, S.-W.,Gozzo, F.,Shin, Namsoo,Kimura, H.,Noda, Y.,Park, J.-G. Nature Publishing Group 2008 Nature Vol.451 No.7180
The motion of atoms in a solid always responds to cooling or heating in a way that is consistent with the symmetry of the given space group of the solid to which they belong. When the atoms move, the electronic structure of the solid changes, leading to different physical properties. Therefore, the determination of where atoms are and what atoms do is a cornerstone of modern solid-state physics. However, experimental observations of atomic displacements measured as a function of temperature are very rare, because those displacements are, in almost all cases, exceedingly small. Here we show, using a combination of diffraction techniques, that the hexagonal manganites RMnO<SUB>3</SUB> (where R is a rare-earth element) undergo an isostructural transition with exceptionally large atomic displacements: two orders of magnitude larger than those seen in any other magnetic material, resulting in an unusually strong magneto-elastic coupling. We follow the exact atomic displacements of all the atoms in the unit cell as a function of temperature and find consistency with theoretical predictions based on group theories. We argue that this gigantic magneto-elastic coupling in RMnO<SUB>3</SUB> holds the key to the recently observed magneto-electric phenomenon in this intriguing class of materials.