Christen 2013 Abstract MiP2013

Christen F, Desrosiers V, Blier PU (2013) Thermal sensitivity of mitochondria from arctic charr heart: Mitochondrial respiration and ROS production. Mitochondr Physiol Network 18.08.

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MiP2013, Book of Abstracts Open Access

Christen F, Desrosiers V, Blier PU (2013)

Event: MiPNet18.08_MiP2013

In the context of climate change, it is of paramount importance to investigate the thermal sensitivity of aquatic ectoterms [1]. Oxidative phosphorylation in mitochondria is one of the key processes of energy production and is known to be influenced by temperature [2,3]. The aim of our study was to shed light on the specific steps of the electron transfer-pathway (ET-pathway) that contribute to the adaptation of fish to temperature changes. For this purpose, we measured oxygen consumption and hydrogen peroxide production at four different temperatures (10, 15, 20 and 25°C) in mitochondria isolated from arctic charr heart (Salvelinus alpinus) raised at 10 °C. Activities of citrate synthase and cytochrome c oxidase (CIV) were also measured at the same temperatures. Specifically, respiration rates of Complex I and Complex II in both coupled and uncoupled states were determined separately by adding either pyruvate, malate, ADP and FCCP for Complex I or succinate, ADP and FCCP for Complex II. Moreover, respiration rates were also measured in the presence of pyruvate+malate+succinate+ADP allowing the evaluation of Complexes I+II together.

Our preliminary results showed that the Complex I and Complex II respiration rates (taken together) were higher when measured separately than when both complexes worked simultaneously. However, this difference was only significant at 15 °C. This may concomitantly occur with a higher reactive oxygen species production at elevated temperatures, and potentially a disruption of mitochondrial integrity. Subsequent analyses of hydrogen peroxide production, citrate synthase and CIV activity will give us further insights into the thermal sensitivity of arctic charr heart mitochondria.

• Keywords: Arctic charr, Topics:Effects of temperature

• O2k-Network Lab: CA Rimouski Blier PU

Labels: MiParea: Respiration, Comparative MiP;environmental MiP 

Stress:Oxidative stress;RONS  Organism: Other mammals, Fishes  Tissue;cell: Heart  Preparation: Isolated mitochondria  Enzyme: Marker enzyme  Regulation: Inhibitor, Temperature  Coupling state: OXPHOS, ET  Pathway: N, S, CIV, NS, ROX  HRR: Oxygraph-2k 

MiP2013, S04 

Affiliations and author contributions

Dept de biologie, Université du Québec à Rimouski, Canada. - Email: [email protected]

References

1. Pörtner HO, Knust R (2007) Climate change affects marine fishes through the oxygen limitation of thermal tolerance. Science 315: 95.
2. Lemieux H, Tardif JC, Dutil JD, Blier PU (2010) Thermal sensitivity of cardiac mitochondrial metabolism in an ectothermic species from a cold environment, Atlantic wolffish (Anarhichas lupus). J Exp Mar Biol Ecol 384: 113–118.
3. Pichaud N, Chatelain EH, Ballard JWO, Tanguay R, Morrow G, Blier PU (2010) Thermal sensitivity of mitochondrial metabolism in two distinct mitotypes of Drosophila simulans: evaluation of mitochondrial plasticity. J Exp Biol 213: 1665–1675.