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Difference between revisions of "O2k-Specifications"

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{{MitoPedia
{{Technical support}}
|description=From their basic design, multi-well systems are a tool for qualitative high-throughput screening, particularly for pharmacologic testing. Designed for high-throughput qualitative measurements, they should not be advertised for quantitative measurements.  A high standard of quantitative results cannot be obtained with the present technology offered and advertised. The problems of high oxygen diffusion are well known, and the large corrections render [[Talk:Rogers_2011_PlosOne#Instrumental_specifications_of_the_XF_multi-well_system_are_missing|non-specified errors in the calculation of background-corrected oxygen flux]].
__TOC__
|info=[http://www.oroboros.at/index.php?hrr-versus-multiwell HRR versus multiwell]
{{MitoPedia without banner
|type=Respiration
|abbr=
|description=[[Image:O2k-Info.png|right|30px|link=Oroboros O2k]]'''O2k versus multiwell respirometer''': '''O2k''' stands for Oroboros O2k and '''[[high-resolution respirometry]]''', meeting powerful quality criteria securing '''high output''' and pioneering state-of-the-art [[Gnaiger_2012_MitoPathways|comprehensive OXPHOS analysis]] of substrate control and coupling control of mitochondrial function. 'High throughput' stands for disposable multiwell systems - expensive, with limited scope and extremely high running costs. In respirometry, high throughput is not equivalent to high output. ''If you’re using a biased instrument, it doesn’t matter how many measurements you take – you’re aiming at the wrong target'' ([[Silver 2012 Penguin Press]]).
|info= [[MiPNet18.10 O2k-Specifications]], [http://wiki.oroboros.at/images/9/93/Flyer_backside_.png Flyer with specification summary]
}}
}}
{{MitoPedia topics|type=Respiration
{{MitoPedia O2k and high-resolution respirometry
|mitopedia O2k and high-resolution respirometry=O2k hardware
}}
}}
* Discussion: [[Talk:Rogers_2011_PlosOne|Seahorse XF for isolated mitochondria - High throughput without high output?]]
* [[Talk:Multiwell respirometer|Correspondence]]


==Quantitative respirometry: HRR versus multiwell==
[[File:Questions.jpg|left|40px]]
<br />
<div class="toccolours mw-collapsible mw-collapsed">
::: <span style="font-size:105%; color:##424242">'''» Keywords'''</span>
<div class="mw-collapsible-content">
::::» [[Gnaiger 2012 MitoPathways|Comprehensive OXPHOS analysis]]
::::» [[High-output, low running costs]]
::::» [[O2k-Publications: Topics]]
::::» [[Power-O2k]]
::::» [[Specifications of the O2k]]'''
</div>
</div>
<br />


The OROBOROS [[Oxygraph-2k]] for [[high-resolution respirometry]] (HRR) is the gold standard for highly accurate quantitative measurements, using very low amounts of sample.  Instrumental and methodological approaches require an adequately advanced level of [http://www.oroboros.at/index.php?qa-in-respirometry Quality Assurance] in research and clinical applications.


===HRR===


HRR is the result of long-term expertise in instrumental design, software development, and [http://www.oroboros.at/index.php?mipnet-protocols experimental protocols] developed for mitochondrial physiology, clinical and pharmacological applications. Taken together, these developments resulted in new qualitative and quantitative standards summarized as the [http://www.oroboros.at/index.php?o2k-concept O2k-Concept].  
== Combination of interests ==
:::: [[Gnaiger E|Erich Gnaiger]] is founder and CEO of Oroboros Instruments, and responsible for the development of the O2k in collaboration with the O2k-Team and our partners. A series of methodological publications is the result of positive feedback between his work as faculty staff of the Medical University of Innsbruck, his company initiatives and numerous international cooperations.


The [http://www.oroboros.at/index.php?o2k-specifications] specifications of the OROBOROS O2k are based on the many unique instrumental features: 


* Critical selection of materials yielding a nearly [http://www.oroboros.at/index.php?backgroundcorrection diffusion-tight] chamber,
== Selected references ==
* Long-term stability and linearity of the polarographic oxygen sensor ([http://www.oroboros.at/index.php?o2k-pos POS]),
* Highly automatic but transparent calibration routines and instrumental background correction,
* Electronically controlled thermal environment with high temperature stability (+-0.001 °C),
* Limit of detection of respiratory flux: +-1 pmol.s-1.ml-1.


===Multi-well===
[[Comparison of respirometric methods]] - [[Talk:Comparison of respirometric methods | Discussion]]


From their basic design, multi-well systems are a tool for qualitative high-throughput screening, particularly for pharmacologic testing.  Designed for high-throughput qualitative measurements, they should not be advertised for quantitative measurements.  A high standard of quantitative results cannot be obtained with the present technology offered and advertised.  Huge oxygen fluxes reported by one group at a mitochondrial physiology meeting (MiPsummer School 2009, Baton Rouge, USA) were explained by a company representative as a "software problem". The absolute oxygen fluxes represent artefacts. More recently, the problems of high oxygen diffusion were recognized, but the large corrections render non-specified errors in the calculation of background-corrected oxygen flux.
::::* Horscroft JA, Kotwica AO, Laner V, West JA, Hennis PJ, Levett DZH, Howard DJ, Fernandez BO, Burgess SL, Ament Z, Gilbert-Kawai ET, Vercueil A, Landis BD, Mitchell K, Mythen MG, Branco C, Johnson RS, Feelisch M, Montgomery HE, Griffin JL, Grocott MPW, Gnaiger E, Martin DS, Murray AJ (2017) Metabolic basis to Sherpa altitude adaptation. Proc Natl Acad Sci U S A 114:6382–7. - [[Horscroft 2017 Proc Natl Acad Sci U S A |»Bioblast link«]]


==Is plastic material compatible with respirometry?==
::::* Lemieux H, Blier PU, Gnaiger E (2017) Remodeling pathway control of mitochondrial respiratory capacity by temperature in mouse heart: electron flow through the Q-junction in permeabilized fibers. Sci Rep 7:2840. - [[Lemieux 2017 Sci Rep |»Bioblast link«]]


===HRR===
::::* Lemieux H, Subarsky P, Doblander C, Wurm M, Troppmair J, Gnaiger E (2017) Impairment of mitochondrial respiratory function as an early biomarker of apoptosis induced by growth factor removal. bioRxiv doi: https://doi.org/10.1101/151480. - [[Lemieux 2017 bioRxiv 151480 |»Bioblast link«]]


Plastic materials with high oxygen diffusion are eliminated from the chamber in HRR. The durane glass chambers are closed by PVDF or PEEK stoppers which are as diffusion tight as our titanium stoppers (originally used in O2k Series A and B). The magnetic stirrer bars are coated by PVDF or PEEK.  Viton O-rings for used for sealing the stoppers, and buyl rubber gaskets provide the seals for the oxygen sensors. 
::::* Gnaiger E, Boushel R, Søndergaard H, Munch-Andersen T, Damsgaard R, Hagen C, Díez-Sánchez C, Ara I, Wright-Paradis C, Schrauwen P, Hesselink M, Calbet JAL, Christiansen M, Helge JW, Saltin B (2015) Mitochondrial coupling and capacity of oxidative phosphorylation in skeletal muscle of Inuit and caucasians in the arctic winter. Scand J Med Sci Sports 25 (Suppl 4):126–34. - [[Gnaiger 2015 Scand J Med Sci Sports| »Bioblast link«]]


HRR not only minimizes the effect of backdiffusion by avoiding inappropriate plastic materials, but additionally implements automatic correction for instrumental background flux (see [http://www.oroboros.at/index.php?o2k-specifications O2k-specifications]).
::::* Harrison DK, Fasching M, Fontana-Ayoub M, Gnaiger E (2015) Cytochrome redox states and respiratory control in mouse and beef heart mitochondria at steady-state levels of hypoxia. J Appl Physiol 119:1210-8. - [[Harrison 2015 J Appl Physiol |»Bioblast link«]]


::::* Makrecka-Kuka M, Krumschnabel G, Gnaiger E (2015) High-resolution respirometry for simultaneous measurement of oxygen and hydrogen peroxide fluxes in permeabilized cells, tissue homogenate and isolated mitochondria. Biomolecules 5:1319-38. - [[Makrecka-Kuka 2015 Biomolecules |»Bioblast link«]]


===Multi-well===
::::* Gnaiger E (2020) Mitochondrial pathways and respiratory control. An introduction to OXPHOS analysis. 5th ed. Bioenerg Commun:112 pp. »[[Gnaiger 2020 BEC MitoPathways |Bioblast link«]]


Oxygen storage in the plastic material of multiwell plates leads to high oxygen backdiffusion. Since the problems are well known ([[Gnaiger_1995_JBB]]), specifications should be provided on backdiffusion, and test protocols applied to enable evaluation of such specifications. 
::::* Pesta D, Gnaiger E (2012) High-resolution respirometry. OXPHOS protocols for human cells and permeabilized fibres from small biopsies of human muscle. Methods Mol Biol 810:25-58. [[Pesta 2012 Methods Mol Biol |»Bioblast link«]]  


At the high surface-to-volume ratio, the problem is not restricted to oxygen diffusion, but all lipid soluble substances partition between the aqueous and plastic phase, such that the surface-attached biological sample is exposed to undefined effective concentrations.  
::::* Votion DM, Gnaiger E, Lemieux H, Mouithys-Mickalad A, Serteyn D (2012) Physical fitness and mitochondrial respiratory capacity in horse skeletal muscle. PLoS One 7: e34890. [[Votion 2012 PLoS One ||»Bioblast link«]]


::::* Lemieux H, Semsroth S, Antretter H, Höfer D, Gnaiger E (2011) Mitochondrial respiratory control and early defects of oxidative phosphorylation in the failing human heart. Int J Biochem Cell Biol 43:1729–38. - [[Lemieux 2011 Int J Biochem Cell Biol |»Bioblast link«]]


==Accuracy of chamber volume and mixing==
::::* Pesta D, Hoppel F, Macek C, Messner H, Faulhaber M, Kobel C, Parson W, Burtscher M, Schocke M, Gnaiger E (2011) Similar qualitative and quantitative changes of mitochondrial respiration following strength and endurance training in normoxia and hypoxia in sedentary humans. Am J Physiol Regul Integr Comp Physiol 301:R1078–87. - [[Pesta 2011 Am J Physiol Regul Integr Comp Physiol |»Bioblast link«]]


===HRR===
::::* Scandurra FM, Gnaiger E (2010) Cell respiration under hypoxia: facts and artefacts in mitochondrial oxygen kinetics. Adv Exp Med Biol 662:7-25. - [[Scandurra 2010 Adv Exp Med Biol |»Bioblast link«]]


The 2 ml standard chamber volume of the O2k is calibrated at <1% error (depending on calibrated pipettes), when inserting the stopper and filling the capillary at an error of <20 µl.  
::::* Aguirre E, Rodríguez-Juárez F, Bellelli A, Gnaiger E, Cadenas S (2010) Kinetic model of the inhibition of respiration by endogenous nitric oxide in intact cells. Biochim Biophys Acta 1797:557-65. - [[Aguirre 2010 Biochim Biophys Acta ||»Bioblast link«]]


The entire effective volume (excluding the injection capillaries) is and well controlled stirring is provided in the O2k.  
::::* Aragonés J, Schneider M, Van Geyte K, Fraisl P, Dresselaers T, Mazzone M, Dirkx R, Zacchigna S, Lemieux H, Jeoung NH, Lambrechts D, Bishop T, Lafuste P, Diez-Juan A, K Harten S, Van Noten P, De Bock K, Willam C, Tjwa M, Grosfeld A, Navet R, Moons L, Vandendriessche T, Deroose C, Wijeyekoon B, Nuyts J, Jordan B, Silasi-Mansat R, Lupu F, Dewerchin M, Pugh C, Salmon P, Mortelmans L, Gallez B, Gorus F, Buyse J, Sluse F, Harris RA, Gnaiger E, Hespel P, Van Hecke P, Schuit F, Van Veldhoven P, Ratcliffe P, Baes M, Maxwell P, Carmeliet P (2008) Deficiency or inhibition of oxygen sensor Phd1 induces hypoxia tolerance by reprogramming basal metabolism. Nat Genet 40:170-80. - [[Aragones 2008 Nat Genet |»Bioblast link«]]


===Multi-well===
::::* Gnaiger E (2008) Polarographic oxygen sensors, the oxygraph and high-resolution respirometry to assess mitochondrial function. In: Mitochondrial Dysfunction in Drug-Induced Toxicity (Dykens JA, Will Y, eds) John Wiley:327-52. - [[Gnaiger_2008_POS |»Bioblast link«]]


No information is provided on the accuracy of the chamber volume in a multi-well system (~7 µl for the XF24).  This inaccuracy translates directly to the calculation of oxyge flux in the closed chamber. Similarly, accurate concentrations of titrated substances are not known.
::::* Hütter E, Renner K, Pfister G, Stöckl P, Jansen-Dürr P, Gnaiger E (2004) Senescence-associated changes in respiration and oxidative phosphorylation in primary human fibroblasts. Biochem J 380:919-28. - [[Huetter_2004_Biochem J |»Bioblast link«]]


Mixing by moving the sensor/injector part up and down a few times is inadequate. Undefined diffusion layers develop during a measuring cycle.  
::::* Kuznetsov AV, Schneeberger S, Seiler R, Brandacher G, Mark W, Steurer W, Saks V, Usson Y, Margreiter R, Gnaiger E (2004) Mitochondrial defects and heterogeneous cytochrome ''c'' release after cardiac cold ischemia and reperfusion. Am J Physiol Heart Circ Physiol 286:H1633–41. - [[Kuznetsov_2004_Am_J_Physiol_Heart_Circ_Physiol |»Bioblast link«]]


==Flexibility for MultiSensor applications==
::::* Gnaiger E (2001) Bioenergetics at low oxygen: dependence of respiration and phosphorylation on oxygen and adenosine diphosphate supply. Respir Physiol 128:277-97. - [[Gnaiger 2001 Respir Physiol |»Bioblast link«]]


===HRR===
::::* Gnaiger E, Méndez G, Hand SC (2000) High phosphorylation efficiency and depression of uncoupled respiration in mitochondria under hypoxia. Proc Natl Acad Sci U S A 97:11080-5. [[Gnaiger 2000 Proc Natl Acad Sci U S A |»Open Access«]]


The O2k is designed for flexible upgrading to the O2k-MultiSensor System, which allows for additional potentiometric measurment of mitochondrial membrane potential (ion sensitive electrode: TPP+), Ca2+ in solution (using the same ion sensitive electrode after mounting a different membrane), pH, and amperometric measurement of NO or H2S, always simultaneously with oxygen flux. The DatLab software provides full flexibility for MultiSensor data monitoring.  
::::* Steinlechner-Maran R, Eberl T, Kunc M, Margreiter R, Gnaiger E (1996) Oxygen dependence of respiration in coupled and uncoupled endothelial cells. Am J Physiol Cell Physiol 271:C2053-61. - [[Steinlechner-Maran_1996_Am J Physiol Cell Physiol |»Bioblast link«]]


===Multi-well===
::::* Gnaiger E, Steinlechner-Maran R, Méndez G, Eberl T, Margreiter R (1995) Control of mitochondrial and cellular respiration by oxygen. J Bioenerg Biomembr 27:583-96. - [[Gnaiger 1995 J Bioenerg Biomembr |»Bioblast link«]]


The XF system is restricted to the additional measurement of pH. No specifications are given on sensitivity [µpH/s] of the measurement of acidification rate. Until recently, the effects of buffers including the bicarbonate system have been ignored.  The rate of acidification was presented in pH units per time, ignoring the log scale of pH.  What is the drift of the pH signal?.  An oxygen flux of 50 pmol/(s ml) corresponds - at an assumed O2 flux to extracellular H+ flux ratio of 1:1 - to a pH change of about 86 µpH/s in a very weak buffer (2 mM).




==How are cell number or mitochondrial protein defined?==
===HRR===


In experiments with isolated mitochondria, tissue homogenates or suspended intact or permeabilized cells, the final concentration in the O2k-chamber is either defined by the preparation of the added suspension, and/or determined by taking a subsample from the chamber.  In this way, the measured oxygen flux (per volume) can be expressed accurately per unit of biological sample (per mg protein, per million cells, etc.).
{{MitoPedia O2k and high-resolution respirometry
 
|mitopedia O2k and high-resolution respirometry=O2k hardware, O2k-Open Support, O2k-Respirometry, O2k-FluoRespirometry
In experiments with permeabilized muscle fibers or other tissues, the tissue mass is determined before adding the sample into the O2k-chamber (e.g. 0.7 mg wet weight of mouse heart, 2 mg wet weight of human muscle), and the oxygen flux can then be expressed per tissue mass (mass-specific flux, reflecting mitochondrial density and functional quality).
}}
 
[[Category:OroboPedia]]
===Multi-well===
[[Category:MitoPedia]]
 
How many cells are actually in the closed compartment for measurement of respiration in a well, or which fraction of isolated mitochondria is outside versus inside the effective chamber?  How can the recorded change in oxygen concentration be converted to respiration per million cells or per mg protein? Without solving these problems, no quantiative measurements of respiration are possible.
 
 
==Are multiple substrate-uncouplier-inhibitor titrations possible?==
===HRR===
 
[[Substrate-uncoupler-inhibitor titration]] (SUIT) protocols have been developed for diagnostic tests of mitochondrial respiratory function, to study the complex interactions of coupling control and substrate control in a single assay, thus increasing the information obtained per unit sample and per unit time.  Up to 20 titration steps may be included in a single SUIT protocol.
 
===Multi-well===
 
The number of different substances that can be titrated into a well is limited, such that modern SUIT protocols cannot be applied in multi-well systems.  A 24 well plate with four titrations per well, or a 96 well plate with two titrations per well are insufficient for obtaining the information from a SUIT experiment.
 
==How high are the running costs?==
 
===HRR===
 
The [http://www.oroboros.at/index.php?low-o2k-running-costs running costs for the OROBOROS O2k] are very very low.
 
The OROBOROS O2k is not suited for a high-throughput approach.  However, investing the identical amount of money, a large number of O2k chambers provides a unique high-throughput HRR system for quantitative O2k-measurements at low running costs.
 
===Multi-well===
 
The running costs are extremely high, based on expensive dischargeable wells for single use only. 
 
How many of the wells of a dischargeable plate can actually be used for independent measurements?  Several wells are required for calibration, edge effects may eliminate the use of wells on the sides.
 
Elaborating a protocol for starting an experimental series requires a large number of test experiments, such that the cost of discharged wells in an entire experiment approaches the investment into a second HRR system.
 
 
==Are specifications comparable?==
 
===HRR===
 
There are detailed and [http://www.oroboros.at/index.php?o2k-specifications unique specifications for the O2k].
 
 
===Multi-well===
 
No specifications are given on sensitivity (lower limit of detection of oxygen; non-linearity and restricted linear range; detection limit of oxygen flux) in some multi well systems.

Latest revision as of 09:37, 20 April 2021


                  


O2k-Open Support

O2k-Specifications



Template NextGen-O2k.jpg


MitoPedia O2k and high-resolution respirometry: O2k-Open Support 



Description

O2k-Info.png

O2k versus multiwell respirometer: O2k stands for Oroboros O2k and high-resolution respirometry, meeting powerful quality criteria securing high output and pioneering state-of-the-art comprehensive OXPHOS analysis of substrate control and coupling control of mitochondrial function. 'High throughput' stands for disposable multiwell systems - expensive, with limited scope and extremely high running costs. In respirometry, high throughput is not equivalent to high output. If you’re using a biased instrument, it doesn’t matter how many measurements you take – you’re aiming at the wrong target (Silver 2012 Penguin Press).


Reference: MiPNet18.10 O2k-Specifications, Flyer with specification summary


MitoPedia O2k and high-resolution respirometry: O2k hardware 


Questions.jpg




Combination of interests

Erich Gnaiger is founder and CEO of Oroboros Instruments, and responsible for the development of the O2k in collaboration with the O2k-Team and our partners. A series of methodological publications is the result of positive feedback between his work as faculty staff of the Medical University of Innsbruck, his company initiatives and numerous international cooperations.


Selected references

Comparison of respirometric methods -  Discussion
  • Horscroft JA, Kotwica AO, Laner V, West JA, Hennis PJ, Levett DZH, Howard DJ, Fernandez BO, Burgess SL, Ament Z, Gilbert-Kawai ET, Vercueil A, Landis BD, Mitchell K, Mythen MG, Branco C, Johnson RS, Feelisch M, Montgomery HE, Griffin JL, Grocott MPW, Gnaiger E, Martin DS, Murray AJ (2017) Metabolic basis to Sherpa altitude adaptation. Proc Natl Acad Sci U S A 114:6382–7. - »Bioblast link«
  • Lemieux H, Blier PU, Gnaiger E (2017) Remodeling pathway control of mitochondrial respiratory capacity by temperature in mouse heart: electron flow through the Q-junction in permeabilized fibers. Sci Rep 7:2840. - »Bioblast link«
  • Lemieux H, Subarsky P, Doblander C, Wurm M, Troppmair J, Gnaiger E (2017) Impairment of mitochondrial respiratory function as an early biomarker of apoptosis induced by growth factor removal. bioRxiv doi: https://doi.org/10.1101/151480. - »Bioblast link«
  • Gnaiger E, Boushel R, Søndergaard H, Munch-Andersen T, Damsgaard R, Hagen C, Díez-Sánchez C, Ara I, Wright-Paradis C, Schrauwen P, Hesselink M, Calbet JAL, Christiansen M, Helge JW, Saltin B (2015) Mitochondrial coupling and capacity of oxidative phosphorylation in skeletal muscle of Inuit and caucasians in the arctic winter. Scand J Med Sci Sports 25 (Suppl 4):126–34. - »Bioblast link«
  • Harrison DK, Fasching M, Fontana-Ayoub M, Gnaiger E (2015) Cytochrome redox states and respiratory control in mouse and beef heart mitochondria at steady-state levels of hypoxia. J Appl Physiol 119:1210-8. - »Bioblast link«
  • Makrecka-Kuka M, Krumschnabel G, Gnaiger E (2015) High-resolution respirometry for simultaneous measurement of oxygen and hydrogen peroxide fluxes in permeabilized cells, tissue homogenate and isolated mitochondria. Biomolecules 5:1319-38. - »Bioblast link«
  • Gnaiger E (2020) Mitochondrial pathways and respiratory control. An introduction to OXPHOS analysis. 5th ed. Bioenerg Commun:112 pp. »Bioblast link«
  • Pesta D, Gnaiger E (2012) High-resolution respirometry. OXPHOS protocols for human cells and permeabilized fibres from small biopsies of human muscle. Methods Mol Biol 810:25-58. »Bioblast link«
  • Votion DM, Gnaiger E, Lemieux H, Mouithys-Mickalad A, Serteyn D (2012) Physical fitness and mitochondrial respiratory capacity in horse skeletal muscle. PLoS One 7: e34890. |»Bioblast link«
  • Lemieux H, Semsroth S, Antretter H, Höfer D, Gnaiger E (2011) Mitochondrial respiratory control and early defects of oxidative phosphorylation in the failing human heart. Int J Biochem Cell Biol 43:1729–38. - »Bioblast link«
  • Pesta D, Hoppel F, Macek C, Messner H, Faulhaber M, Kobel C, Parson W, Burtscher M, Schocke M, Gnaiger E (2011) Similar qualitative and quantitative changes of mitochondrial respiration following strength and endurance training in normoxia and hypoxia in sedentary humans. Am J Physiol Regul Integr Comp Physiol 301:R1078–87. - »Bioblast link«
  • Scandurra FM, Gnaiger E (2010) Cell respiration under hypoxia: facts and artefacts in mitochondrial oxygen kinetics. Adv Exp Med Biol 662:7-25. - »Bioblast link«
  • Aguirre E, Rodríguez-Juárez F, Bellelli A, Gnaiger E, Cadenas S (2010) Kinetic model of the inhibition of respiration by endogenous nitric oxide in intact cells. Biochim Biophys Acta 1797:557-65. - |»Bioblast link«
  • Aragonés J, Schneider M, Van Geyte K, Fraisl P, Dresselaers T, Mazzone M, Dirkx R, Zacchigna S, Lemieux H, Jeoung NH, Lambrechts D, Bishop T, Lafuste P, Diez-Juan A, K Harten S, Van Noten P, De Bock K, Willam C, Tjwa M, Grosfeld A, Navet R, Moons L, Vandendriessche T, Deroose C, Wijeyekoon B, Nuyts J, Jordan B, Silasi-Mansat R, Lupu F, Dewerchin M, Pugh C, Salmon P, Mortelmans L, Gallez B, Gorus F, Buyse J, Sluse F, Harris RA, Gnaiger E, Hespel P, Van Hecke P, Schuit F, Van Veldhoven P, Ratcliffe P, Baes M, Maxwell P, Carmeliet P (2008) Deficiency or inhibition of oxygen sensor Phd1 induces hypoxia tolerance by reprogramming basal metabolism. Nat Genet 40:170-80. - »Bioblast link«
  • Gnaiger E (2008) Polarographic oxygen sensors, the oxygraph and high-resolution respirometry to assess mitochondrial function. In: Mitochondrial Dysfunction in Drug-Induced Toxicity (Dykens JA, Will Y, eds) John Wiley:327-52. - »Bioblast link«
  • Hütter E, Renner K, Pfister G, Stöckl P, Jansen-Dürr P, Gnaiger E (2004) Senescence-associated changes in respiration and oxidative phosphorylation in primary human fibroblasts. Biochem J 380:919-28. - »Bioblast link«
  • Kuznetsov AV, Schneeberger S, Seiler R, Brandacher G, Mark W, Steurer W, Saks V, Usson Y, Margreiter R, Gnaiger E (2004) Mitochondrial defects and heterogeneous cytochrome c release after cardiac cold ischemia and reperfusion. Am J Physiol Heart Circ Physiol 286:H1633–41. - »Bioblast link«
  • Gnaiger E (2001) Bioenergetics at low oxygen: dependence of respiration and phosphorylation on oxygen and adenosine diphosphate supply. Respir Physiol 128:277-97. - »Bioblast link«
  • Gnaiger E, Méndez G, Hand SC (2000) High phosphorylation efficiency and depression of uncoupled respiration in mitochondria under hypoxia. Proc Natl Acad Sci U S A 97:11080-5. »Open Access«
  • Steinlechner-Maran R, Eberl T, Kunc M, Margreiter R, Gnaiger E (1996) Oxygen dependence of respiration in coupled and uncoupled endothelial cells. Am J Physiol Cell Physiol 271:C2053-61. - »Bioblast link«
  • Gnaiger E, Steinlechner-Maran R, Méndez G, Eberl T, Margreiter R (1995) Control of mitochondrial and cellular respiration by oxygen. J Bioenerg Biomembr 27:583-96. - »Bioblast link«



MitoPedia O2k and high-resolution respirometry: O2k hardware, O2k-Open Support, O2k-Respirometry, O2k-FluoRespirometry