Effects of a high-fat diet on superoxide anion generation and membrane fluidity in liver mitochondria in rats.

BACKGROUND: Obesity is a primary factor of lifestyle-related diseases, and the age of its onset has decreased. The reactive oxygen species (ROS), the superoxide anion, is generated in the mitochondrial electron transport chain and the damage it induces in cells may be a contributing factor to obesity-related lifestyle diseases. In the present study, the influence of the ingestion of a high-fat diet (HFD) on superoxide anion generation in rat liver mitochondria (Mt) and membrane fluidity was investigated. METHODS: Male Wistar rats were fed a normal diet (ND, n = 6) or HFD (n = 6). Liver Mt were isolated and oxygen consumption, superoxide anion production (the adrenaline method), and membrane fluidity (the spin label method) were measured. RESULTS: After 11 weeks, body weights and abdominal circumferences were higher in the HFD group than in the ND group. Mt oxygen consumption was higher in the HFD group than in the ND group. Superoxide anion production was significantly lower in the HFD group than in the ND group, while no significant changes were observed in membrane fluidity. CONCLUSION: Although rats developed diet-induced obesity, it did not reach the level of disease development. The promotion of lipid metabolism appeared to reduce superoxide anion production, but did not influence membrane fluidity. While superoxide anion damages cells as an oxidative stress, ROS and superoxide dismutase are essential signaling molecules in the body. The present results suggest that the continuous ingestion of a HFD impairs Mt and induces disease development.

Reduction of thickness of ganglion cell complex after internal limiting membrane peeling during vitrectomy for idiopathic macular hole.

BACKGROUND/AIM: The aim of this study is to report a reduction in the thickness of the ganglion cell complex (GCC) after vitrectomy with internal limiting membrane (ILM) peeling in eyes with idiopathic macular hole (MH). METHODS: Twenty-eight consecutive eyes with an idiopathic MH treated by vitrectomy with ILM peeling were studied. All eyes had an intravitreal injection of indocyanine green to make the ILM more visible. The best-corrected visual acuity (BCVA), GCC thickness measured by spectral domain optical coherence tomography, and retinal sensitivity measured by microperimetry were determined before and at 3 and 6 months after the vitrectomy. RESULTS: The MH in all eyes was closed after the initial surgery. The BCVA was significantly improved at 3 and 6 months (P<0.001 and P<0.001, respectively). The thickness of the GCC was significantly reduced at 3 and 6 months postoperatively (P<0.001 and P<0.001, respectively). The GCC thickness was significantly correlated with the retinal sensitivity in the central 10 degrees at 6 months (r=0.55, P=0.004). CONCLUSION: A reduction of the GCC thickness was observed after vitrectomy with ILM peeling for idiopathic MH.

Identification and characterization of the sodA genes encoding manganese superoxide dismutases in Vibrio parahaemolyticus, Vibrio mimicus, and Vibrio vulnificus.

Sequencing of Fur titration assay-positive clones obtained from genomic DNA libraries of Vibrio parahaemolyticus, V. mimicus and V. vulnificus revealed open reading frames encoding proteins of 202, 205 and 202 amino acid residues, respectively. Each open reading frame was preceded by a predicted Fur box which overlaps a likely promoter with similarity to the -10 and -35 consensus sequence of Escherichia coli. The deduced amino acid sequences shared considerable homology with bacterial Mn-containing superoxide dismutases (MnSODs). Consistent with this, these Vibrio strains produced proteins with SOD activity resistant to inhibition by H2O2 and KCN only when grown under iron-limiting conditions. Primer extension analysis of the total RNA from these vibrios revealed iron-repressible expression of the genes. Furthermore, when grown under iron-limiting conditions, E. coli carrying a plasmid with each cloned gene overexpressed protein with the same electrophoretic mobility and insensitivity of SOD activity to H2O2 and KCN. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by N-terminal amino acid sequencing revealed that proteins (MnSODs) having N-terminal amino acid sequences consistent with those deduced from the corresponding genes were present in cell lysates of the vibrios grown under these iron-limited conditions. These results demonstrate that the genes cloned in this study are sodA homologs encoding MnSODs, whose expression is regulated by the iron status of the growth medium. PCR using a primer set based on the V. parahaemolyticus sodA sequence revealed the presence of homologous genes in certain other Vibrio species.