Pichaud 2011 Am J Physiol Regul Integr Comp Physiol

Pichaud N, Ballard JWO, Tanguay RM, Blier PU (2011)Thermal sensitivity of mitochondrial functions in permeabilized muscle fibers from two populations of Drosophila simulans with divergent mitotypes. Am J Physiol Regul Integr Comp Physiol 301: R48-R49.

» PMID:21451139

Pichaud N, Ballard JWO, Tanguay RM, Blier PU (2011) Am J Physiol Regul Integr Comp Physiol

Abstract: In ectotherms, the external temperature is experienced by the mitochondria, and the mitochondrial respiration of different genotypes is likely to change as a result. Using high-resolution respirometry with permeabilized fibers (an in situ approach), we tried to identify differences in mitochondrial performance and thermal sensitivity of two Drosophila simulans populations with two different mitochondrial types (siII and siIII) and geographical distributions. Maximal State 3 respiration rates obtained with electrons converging at the Q junction of the electron transport system (ETS) differed between the mitotypes at 24 °C. Catalytic capacities were higher in flies harboring siII than in those harboring siIII mitochondrial DNA (2,129 vs. 1,390 pmol O2·s^-1·mg protein^-1). The cytochrome c oxidase activity was also higher in siII than siIII flies (3,712 vs. 2,688 pmol O2·s^-1·mg protein^-1). The higher catalytic capacity detected in the siII mitotype could provide an advantage in terms of intensity of aerobic activity, endurance, or both, if the intensity of exercise that can be aerobically performed is partly dictated by the aerobic capacity of the tissue. Moreover, thermal sensitivity results showed that even if temperature affects the catalytic capacity of the different enzymes of the ETS, both mitotypes revealed high tolerance to temperature variation. Previous in vitro study failed to detect any consistent functional mitochondrial differences between the same mitotypes. We conclude that the in situ approach is more sensitive and that the ETS is a robust system in terms of functional and regulatory properties across a wide range of temperatures. • Keywords: metabolism; mitochondrial DNA; mitochondrial respiration; temperature; Drosophila simulans

• O2k-Network Lab: CA_Rimouski_Blier PU, AU Sydney Ballard JWO

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Stress:z in prep"z in prep" is not in the list (Cell death, Cryopreservation, Ischemia-reperfusion, Permeability transition, Oxidative stress;RONS, Temperature, Hypoxia, Mitochondrial disease) of allowed values for the "Stress" property.  Organism: Other Non-Mammal"Other Non-Mammal" is not in the list (Human, Pig, Mouse, Rat, Guinea pig, Bovines, Horse, Dog, Rabbit, Cat, ...) of allowed values for the "Mammal and model" property.  Tissue;cell: Skeletal Muscle"Skeletal Muscle" is not in the list (Heart, Skeletal muscle, Nervous system, Liver, Kidney, Lung;gill, Islet cell;pancreas;thymus, Endothelial;epithelial;mesothelial cell, Blood cells, Fat, ...) of allowed values for the "Tissue and cell" property.  Preparation: Permeabilized Tissue"Permeabilized Tissue" is not in the list (Intact organism, Intact organ, Permeabilized cells, Permeabilized tissue, Homogenate, Isolated mitochondria, SMP, Chloroplasts, Enzyme, Oxidase;biochemical oxidation, ...) of allowed values for the "Preparation" property.  Enzyme: z in prep"z in prep" is not in the list (Adenine nucleotide translocase, Complex I, Complex II;succinate dehydrogenase, Complex III, Complex IV;cytochrome c oxidase, Complex V;ATP synthase, Inner mt-membrane transporter, Marker enzyme, Supercomplex, TCA cycle and matrix dehydrogenases, ...) of allowed values for the "Enzyme" property.  Regulation: z in prep"z in prep" is not in the list (Aerobic glycolysis, ADP, ATP, ATP production, AMP, Calcium, Coupling efficiency;uncoupling, Cyt c, Flux control, Inhibitor, ...) of allowed values for the "Respiration and regulation" property. 

HRR: Oxygraph-2k