The Experts below are selected from a list of 285 Experts worldwide ranked by ideXlab platform
Isabella Panfoli - One of the best experts on this subject based on the ideXlab platform.
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Modulation of the rod outer segment Aerobic Metabolism diminishes the production of radicals due to light absorption.
Free radical biology & medicine, 2018Co-Authors: Daniela Calzia, Paolo Degan, Federico Caicci, Maurizio Bruschi, Lucia Manni, Luca A. Ramenghi, Giovanni Candiano, Carlo Enrico Traverso, Isabella PanfoliAbstract:Abstract Oxidative stress is a primary risk factor for both inflammatory and degenerative retinopathies. Our previous data on blue light-irradiated retinas demonstrated an oxidative stress higher in the rod outer segment (OS) than in the inner limb, leading to impairment of the rod OS extra-mitochondrial Aerobic Metabolism. Here the oxidative Metabolism and Reactive Oxygen Intermediates (ROI) production was evaluated in purified bovine rod OS in function of exposure to different illumination conditions. A dose response was observed to varying light intensities and duration in terms of both ROI production and ATP synthesis. Pretreatment with resveratrol, inhibitor of F1Fo-ATP synthase, or metformin, inhibitor of the respiratory complex I, significantly diminished the ROI production. Metformin also diminished the rod OS Complex I activity and reduced the maximal OS response to light in ATP production. Data show for the first time the relationship existing in the rod OS between its -Aerobic- Metabolism, light absorption, and ROI production. A beneficial effect was exerted by metformin and resveratrol, in modulating the ROI production in the illuminated rod OS, suggestive of their beneficial action also in vivo. Data shed new light on preventative interventions for cone loss secondary to rod damage due to oxidative stress.
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Evidence for Aerobic Metabolism in retinal rod outer segment disks
The international journal of biochemistry & cell biology, 2009Co-Authors: Isabella Panfoli, Silvia Ravera, Daniela Calzia, Giovanni Candiano, Paolo Bianchini, Alberto Diaspro, Angela Bachi, Massimiliano Monticone, Maria Grazia Aluigi, Stefano BarabinoAbstract:The disks of the vertebrate retinal rod Outer Segment (OS), devoid of mitochondria, are the site of visual transduction, a very energy demanding process. In a previous proteomic study we reported the expression of the respiratory chain complexes I-IV and the oxidative phosphorylation Complex V (F(1)F(0)-ATP synthase) in disks. In the present study, the functional localization of these proteins in disks was investigated by biochemical analyses, oxymetry, membrane potential measurements, and confocal laser scanning microscopy. Disk preparations, isolated by Ficoll flotation, were characterized for purity. An oxygen consumption, stimulated by NADH and Succinate and reverted by rotenone, antimycin A and KCN was measured in disks, either in coupled or uncoupled conditions. Rhodamine-123 fluorescence quenching kinetics showed the existence of a proton potential difference across the disk membranes. Citrate synthase activity was assayed and found enriched in disks with respect to ROS. ATP synthesis by disks (0.7 micromol ATP/min/mg), sensitive to the common mitochondrial ATP synthase inhibitors, would largely account for the rod ATP need in the light. Overall, data indicate that an oxidative phosphorylation occurs in rod OS, which do not contain mitochondria, thank to the presence of ectopically located mitochondrial proteins. These findings may provide important new insight into energy production in outer segments via Aerobic Metabolism and additional information about protein components in OS disk membranes.
Christel Lefrancois - One of the best experts on this subject based on the ideXlab platform.
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Allometric relationship between body mass and Aerobic Metabolism in zebrafish Danio rerio
Journal of Fish Biology, 2014Co-Authors: Julie Lucas, Alicia Schouman, Laura Lyphout, Xavier Cousin, Christel LefrancoisAbstract:The relationship between body mass and metabolic rate was investigated through the assessment of active and standard metabolic rate at different life stages in zebrafish Danio rerio (5 day-old larvae, 2 month-old juveniles and 6 month-old adults). Scaling exponents and constants were assessed for standard (RS=0.273M0.965 in mgO2.g-1.h-1) and active metabolic rate (RA=0.799M0.926 in mgO2.g-1.h-1). These data provide the basis for further experiments regarding the effects of environmental factors on Aerobic Metabolism throughout the life cycle of this species.
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PCB contamination does not alter Aerobic Metabolism and tolerance to hypoxia of juvenile sole (Solea solea L. 1758)
Aquatic Toxicology, 2013Co-Authors: Marcella Cannas, Fabrizio Atzori, François Rupsard, Paco Bustamante, Véronique Loizeau, Christel LefrancoisAbstract:Coastal habitats play a major role as nurseries for many fish species; however, they are also submitted to pollutants and oxygen fluctuations. Fry's concept of metabolic scope for activity was used to evaluate the effect of polychlorinated biphenyls (PCBs) on the Aerobic Metabolism in juvenile common sole (0-1 year old). Aerobic metabolic scope (AMS) in control and PCB-contaminated fish via food pathway was determined using respirometry techniques. Furthermore, the hypoxia tolerance in control and PCB-contaminated fish was evaluated by assessing their critical oxygen concentration (O2crit). Our results showed that while PCB-contaminated fish were able to maintain a constant AMS, PCBs tend to affect their Aerobic Metabolism by acting on standard metabolic rate, maximal oxygen consumption (MO2max) in hypoxia and O2crit. In conclusion, we can hypothesise that a long-term exposure to PCBs may decrease their tolerance to hypoxia and consequently impair the survival and/or development of soles in their natural environment.
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PCBs contamination does not alter Aerobic Metabolism and tolerance to hypoxia of juvenile sole (Solea solea L. 1758)
Aquatic toxicology (Amsterdam Netherlands), 2012Co-Authors: Marcella Cannas, Fabrizio Atzori, François Rupsard, Paco Bustamante, Véronique Loizeau, Christel LefrancoisAbstract:Coastal habitats play a major role as nurseries for many fish species; however, they are also submitted to pollutants and oxygen fluctuations. Fry's concept of metabolic scope for activity was used to evaluate the effect of polychlorinated biphenyls (PCBs) on the Aerobic Metabolism in juvenile common sole (0–1 year old). Aerobic metabolic scope (AMS) in control and PCB-contaminated fish via food pathway was determined using respirometry techniques. Furthermore, the hypoxia tolerance in control and PCB-contaminated fish was evaluated by assessing their critical oxygen concentration (O2crit). Our results showed that while PCB-contaminated fish were able to maintain a constant AMS and O2crit, PCBs tend to affect their Aerobic Metabolism by acting on maximal oxygen consumption (MO2max) in hypoxia and standard metabolic rate, but only at the highest PCB concentration between 30 and 60 days of exposure. In conclusion, we can hypothetise that the tested PCB-exposures may not impair the tolerance to hypoxia and the survival of common sole in their natural environment.
Daniela Calzia - One of the best experts on this subject based on the ideXlab platform.
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Modulation of the rod outer segment Aerobic Metabolism diminishes the production of radicals due to light absorption.
Free radical biology & medicine, 2018Co-Authors: Daniela Calzia, Paolo Degan, Federico Caicci, Maurizio Bruschi, Lucia Manni, Luca A. Ramenghi, Giovanni Candiano, Carlo Enrico Traverso, Isabella PanfoliAbstract:Abstract Oxidative stress is a primary risk factor for both inflammatory and degenerative retinopathies. Our previous data on blue light-irradiated retinas demonstrated an oxidative stress higher in the rod outer segment (OS) than in the inner limb, leading to impairment of the rod OS extra-mitochondrial Aerobic Metabolism. Here the oxidative Metabolism and Reactive Oxygen Intermediates (ROI) production was evaluated in purified bovine rod OS in function of exposure to different illumination conditions. A dose response was observed to varying light intensities and duration in terms of both ROI production and ATP synthesis. Pretreatment with resveratrol, inhibitor of F1Fo-ATP synthase, or metformin, inhibitor of the respiratory complex I, significantly diminished the ROI production. Metformin also diminished the rod OS Complex I activity and reduced the maximal OS response to light in ATP production. Data show for the first time the relationship existing in the rod OS between its -Aerobic- Metabolism, light absorption, and ROI production. A beneficial effect was exerted by metformin and resveratrol, in modulating the ROI production in the illuminated rod OS, suggestive of their beneficial action also in vivo. Data shed new light on preventative interventions for cone loss secondary to rod damage due to oxidative stress.
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Evidence for Aerobic Metabolism in retinal rod outer segment disks
The international journal of biochemistry & cell biology, 2009Co-Authors: Isabella Panfoli, Silvia Ravera, Daniela Calzia, Giovanni Candiano, Paolo Bianchini, Alberto Diaspro, Angela Bachi, Massimiliano Monticone, Maria Grazia Aluigi, Stefano BarabinoAbstract:The disks of the vertebrate retinal rod Outer Segment (OS), devoid of mitochondria, are the site of visual transduction, a very energy demanding process. In a previous proteomic study we reported the expression of the respiratory chain complexes I-IV and the oxidative phosphorylation Complex V (F(1)F(0)-ATP synthase) in disks. In the present study, the functional localization of these proteins in disks was investigated by biochemical analyses, oxymetry, membrane potential measurements, and confocal laser scanning microscopy. Disk preparations, isolated by Ficoll flotation, were characterized for purity. An oxygen consumption, stimulated by NADH and Succinate and reverted by rotenone, antimycin A and KCN was measured in disks, either in coupled or uncoupled conditions. Rhodamine-123 fluorescence quenching kinetics showed the existence of a proton potential difference across the disk membranes. Citrate synthase activity was assayed and found enriched in disks with respect to ROS. ATP synthesis by disks (0.7 micromol ATP/min/mg), sensitive to the common mitochondrial ATP synthase inhibitors, would largely account for the rod ATP need in the light. Overall, data indicate that an oxidative phosphorylation occurs in rod OS, which do not contain mitochondria, thank to the presence of ectopically located mitochondrial proteins. These findings may provide important new insight into energy production in outer segments via Aerobic Metabolism and additional information about protein components in OS disk membranes.
Christine Clayton - One of the best experts on this subject based on the ideXlab platform.
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roles of triosephosphate isomerase and Aerobic Metabolism in trypanosoma brucei
Biochemical Journal, 2001Co-Authors: Sandra Helfert, Antonio M Estevez, Barbara M Bakker, Paul A M Michels, Christine ClaytonAbstract:Kinetoplastid protozoa compartmentalize the first seven enzymes of glycolysis and two enzymes of glycerol Metabolism in a microbody, the glycosome. While in its mammalian host, Trypanosoma brucei depends entirely on glucose for ATP generation. Under Aerobic conditions, most of the glucose is metabolized to pyruvate. Aerobic Metabolism depends on the activities of glycosomal triosephosphate isomerase and a mitochondrial glycerophosphate oxidase, and on glycerophosphate dihydroxyacetone phosphate exchange across the glycosomal membrane. Using a combination of genetics and computer modelling, we show that triosephosphate isomerase is probably essential for bloodstream trypanosome survival, but not for the insect-dwelling procyclics, which preferentially use amino acids as an energy source. When the enzyme level decreased to about 15% of that of the wild-type, the growth rate was halved. Below this level, a lethal rise in dihydroxyacetone phosphate was predicted. Expression of cytosolic triosephosphate isomerase inhibited cell growth. Attempts to knockout the trypanosome alternative oxidase genes (which are needed for glycerophosphate oxidase activity) were unsuccessful, but when we lowered the level of the corresponding mRNA by expressing a homologous double-stranded RNA, oxygen consumption was reduced fourfold and the rate of trypanosome growth was halved.
Giovanni Candiano - One of the best experts on this subject based on the ideXlab platform.
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Modulation of the rod outer segment Aerobic Metabolism diminishes the production of radicals due to light absorption.
Free radical biology & medicine, 2018Co-Authors: Daniela Calzia, Paolo Degan, Federico Caicci, Maurizio Bruschi, Lucia Manni, Luca A. Ramenghi, Giovanni Candiano, Carlo Enrico Traverso, Isabella PanfoliAbstract:Abstract Oxidative stress is a primary risk factor for both inflammatory and degenerative retinopathies. Our previous data on blue light-irradiated retinas demonstrated an oxidative stress higher in the rod outer segment (OS) than in the inner limb, leading to impairment of the rod OS extra-mitochondrial Aerobic Metabolism. Here the oxidative Metabolism and Reactive Oxygen Intermediates (ROI) production was evaluated in purified bovine rod OS in function of exposure to different illumination conditions. A dose response was observed to varying light intensities and duration in terms of both ROI production and ATP synthesis. Pretreatment with resveratrol, inhibitor of F1Fo-ATP synthase, or metformin, inhibitor of the respiratory complex I, significantly diminished the ROI production. Metformin also diminished the rod OS Complex I activity and reduced the maximal OS response to light in ATP production. Data show for the first time the relationship existing in the rod OS between its -Aerobic- Metabolism, light absorption, and ROI production. A beneficial effect was exerted by metformin and resveratrol, in modulating the ROI production in the illuminated rod OS, suggestive of their beneficial action also in vivo. Data shed new light on preventative interventions for cone loss secondary to rod damage due to oxidative stress.
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Evidence for Aerobic Metabolism in retinal rod outer segment disks
The international journal of biochemistry & cell biology, 2009Co-Authors: Isabella Panfoli, Silvia Ravera, Daniela Calzia, Giovanni Candiano, Paolo Bianchini, Alberto Diaspro, Angela Bachi, Massimiliano Monticone, Maria Grazia Aluigi, Stefano BarabinoAbstract:The disks of the vertebrate retinal rod Outer Segment (OS), devoid of mitochondria, are the site of visual transduction, a very energy demanding process. In a previous proteomic study we reported the expression of the respiratory chain complexes I-IV and the oxidative phosphorylation Complex V (F(1)F(0)-ATP synthase) in disks. In the present study, the functional localization of these proteins in disks was investigated by biochemical analyses, oxymetry, membrane potential measurements, and confocal laser scanning microscopy. Disk preparations, isolated by Ficoll flotation, were characterized for purity. An oxygen consumption, stimulated by NADH and Succinate and reverted by rotenone, antimycin A and KCN was measured in disks, either in coupled or uncoupled conditions. Rhodamine-123 fluorescence quenching kinetics showed the existence of a proton potential difference across the disk membranes. Citrate synthase activity was assayed and found enriched in disks with respect to ROS. ATP synthesis by disks (0.7 micromol ATP/min/mg), sensitive to the common mitochondrial ATP synthase inhibitors, would largely account for the rod ATP need in the light. Overall, data indicate that an oxidative phosphorylation occurs in rod OS, which do not contain mitochondria, thank to the presence of ectopically located mitochondrial proteins. These findings may provide important new insight into energy production in outer segments via Aerobic Metabolism and additional information about protein components in OS disk membranes.
