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Difference between revisions of "EBEC2014"

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[[File:FleischmannS.jpg|80px|Fleischmann Sandra]] [[Fleischmann S| Fleischmann Sandra]]; Administrative assistant
[[File:FleischmannS.jpg|80px|Fleischmann Sandra]] [[Fleischmann S| Fleischmann Sandra]]; Administrative assistant


== Abstracts ==


=== The relationship between cytochrome redox state and oxygen consumption in isolated mouse and beef heart mitochondria during hypoxia ===
David K Harrison<sup>1,2</sup>, Mario Fasching<sup>1</sup>, Mona Fontana-Ayoub<sup>1</sup> and Erich Gnaiger<sup>1,3</sup>
ย 
<sup>1</sup>Oroboros Instruments, Innsbruck, Austria; <sup>2</sup>Microvascular Measurements, St Lorenzen, Italy; <sup>3</sup>D Swarowski Research Laboratory, Department of Visceral Transplant and Thoracic Surgery, Medical University of Innsbruck, Austria
ย 
This study describes a low-noise, rapid spectrophotometric system using visible light (440-605 nm) for the measurement of cytochrome redox state combined with high-resolution respirometry. The system was tested in an investigation using beef and mouse heart isolated mitochondria (BHImt, MHImt) in order to determine the relationship between respiratory rate and cytochrome redox state at steady-state levels of hypoxia. Monophasic hyperbolic relations were observed between respiratory rate,ย  ''j'' (with glutamate+malate and saturating ADP concentrations), and oxygen partial pressure, ''p''<sub>O2</sub>, in the range <1.1 kPa for both BHImt and MHImt with ''p''<sub>50,''j''</sub> (''p''<sub>O2</sub> at ''j'' = 0.5 ''J''<sub>max</sub>) ofย  0.015 and 0.021 kPa respectively. The oxidation fractions of cytochromes ''aa''3 and ''c'' were biphasic hyperbolic functions of ''p''<sub>O2</sub>. The relationships between cytochrome oxidation states and ''j'' were more complex with an initial steep decrease in the oxidation fraction of cytochrome ''c'' to a value of ''j'' of approximately 0.7 followed by a plateaux and a further steep decrease at ''j'' < 0.2. This relationship was less apparent with cytochrome ''b'' redox state. Using these functions, it was possible to create a model that successfully described the measured relationship between cytochrome oxidation state and oxygen consumption.
Supported by K-Regio project ''[[MitoCom]]''.
ย 


[[Image:MitoGlobal.jpg|right|80px|link=http://www.bioblast.at/index.php/MitoGlobal|MitoGlobal]] ย 
[[Image:MitoGlobal.jpg|right|80px|link=http://www.bioblast.at/index.php/MitoGlobal|MitoGlobal]] ย 
ย  Listed under [[MitoGlobal Events]].
ย  Listed under [[MitoGlobal Events]].

Revision as of 10:12, 23 June 2014

Publications in the MiPMap
Lisbon PT, 2014 Jul 12-17. 18th European Bioenergetics Conference - EBEC2014

ยป EBEC2014

EBEC (2014-07-12) MitoGlobal

Abstract: 18th European Bioenergetics Conference - EBEC2014.


Labels:






ORO, 2014, MitoCom, Next 

Erich Gnaiger Gnaiger Erich, CEO, OROBOROS INSTRUMENTS Fleischmann Sandra Fleischmann Sandra; Administrative assistant

Abstracts

The relationship between cytochrome redox state and oxygen consumption in isolated mouse and beef heart mitochondria during hypoxia

David K Harrison1,2, Mario Fasching1, Mona Fontana-Ayoub1 and Erich Gnaiger1,3

1Oroboros Instruments, Innsbruck, Austria; 2Microvascular Measurements, St Lorenzen, Italy; 3D Swarowski Research Laboratory, Department of Visceral Transplant and Thoracic Surgery, Medical University of Innsbruck, Austria

This study describes a low-noise, rapid spectrophotometric system using visible light (440-605 nm) for the measurement of cytochrome redox state combined with high-resolution respirometry. The system was tested in an investigation using beef and mouse heart isolated mitochondria (BHImt, MHImt) in order to determine the relationship between respiratory rate and cytochrome redox state at steady-state levels of hypoxia. Monophasic hyperbolic relations were observed between respiratory rate, j (with glutamate+malate and saturating ADP concentrations), and oxygen partial pressure, pO2, in the range <1.1 kPa for both BHImt and MHImt with p50,j (pO2 at j = 0.5 Jmax) of 0.015 and 0.021 kPa respectively. The oxidation fractions of cytochromes aa3 and c were biphasic hyperbolic functions of pO2. The relationships between cytochrome oxidation states and j were more complex with an initial steep decrease in the oxidation fraction of cytochrome c to a value of j of approximately 0.7 followed by a plateaux and a further steep decrease at j < 0.2. This relationship was less apparent with cytochrome b redox state. Using these functions, it was possible to create a model that successfully described the measured relationship between cytochrome oxidation state and oxygen consumption.

Supported by K-Regio project MitoCom.


MitoGlobal
Listed under MitoGlobal Events.