Talk:Bioblast alert 2020

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How can you reduce the amount of biological sample needed for high-resolution respirometry?

The O2k-sV-Module provides all the components necessary for a smaller operation volume (0.5 mL) whereby the sample amount used for measuring oxygen flux can be reduced.
- »O2k-sV-Module« 
- communicated by »Komlodi Timea« and »Schmitt Sabine« 

O2k-Open SupportInfo: improve Are whitish deposits forming on the glass wall of the O2k-Chamber?

These deposits might be an accumulation of proteins and subsequent embedding of other biological material or small glass splinters, and a sign that the O2k-Chamber requires cleaning.
For further details on how to clean the O2k-Chamber properly, see:
- »Cleaning the O2k-chamber«
- communicated by »Komlodi Timea«, »Sabine Schmitt«, and »Lisa Tindle-Solomon«

Other topics:

Why are permeabilized muscle fibers (pfi) a poor sample type for studying reactive oxygen species (ROS) production?

In experiments with pfi, high oxygen concentrations are needed to avoid oxygen limitation. However, the high oxygen pressures used may artificially increase ROS, including H2O2 production, making pfi a less optimal model for ROS production studies.
- »Oxygen dependence of ROS production in pfi« 
- communicated by »Komlodi Timea« and »Cardoso Luiza«

O2k-Open Support Take care Why it is necessary to perform multiple H2O2 calibrations when using the Amplex UltraRed (AmR) assay?

The sensitivity to H2O2 of the Amplex UltraRed assay changes during the experiment, thus requires multiple calibrations. These sensitivity changes may be the function of: 1) experimental time, 2) changes in the optical properties of the respiration medium due to sample/chemical titration, 3) the radical scavenging capacity of the sample, and 4) the concentration of accumulating resorufin (UltroxRed in the case of Amplex UltraRed). Therefore, it is recommended to perform H2O2 calibration before sample addition, after sample addition and multiple times during the experiment.
- »Komlodi 2018 Methods Mol Biol« 

The DLPs for AmR SUIT protocols already come with multiple steps of H2O2 calibrations implemented.
- » SUITbrowser« 
- communicated by »Komlodi Timea« and »Cardoso Luiza«

O2k-Open SupportInfo: improve How can you compare respirometric experiments using an internal normalization?

Flux control ratios (FCR) are independent of external measurements (e.g. protein determination, citrate synthase activity) and therefore can be used to analyze data when other normalization methods cannot be applied. Learn more about how to use this option to assess qualitative changes of mitochondrial respiratory control with DatLab and the “O2 analysis template DL7.4”.
- »Flux control ratio«

Read more: Gnaiger Erich et al ― MitoEAGLE Task Group (2020) Mitochondrial physiology. Bioenerg Commun 2020.1 »Bioblast link« 

Non-mitochondrial respiration or residual oxygen consumption (Rox)? — Concept-driven constructive terminology frames our perception.

After inhibition of electron-transfer (ET) pathways or in the absence of fuel substrates, both mitochondrial non-ET reactions and non-mitochondrial reactions contribute to residual oxygen consumption in mt-preparations and living cells.
- »BEC: Mitochondrial physiology« — Table 1: Rox induced by non-ET pathway oxidation reactions

SUIT special

  • Sep-22 Tu
MitoPedia: SUIT Did you know the reverse electron flow from Complex II to Complex I can be investigated in mitochondrial preparations by measuring hydrogen peroxide production using Amplex UltraRed assay?

The reverse electron flow, also called reverse electron transfer (RET), happens when electrons are transferred from Complex II to the Q-junction and then back to Complex I at high mt-membrane potential. This phenomenon results in high hydrogen peroxide production in some mitochondrial preparations. The SUIT-026 protocol was designed to investigate this effect.
- »SUIT-026« 
- communicated by »Komlodi Timea« and »Cardoso Luiza« 

  • Sep-17 Th
MitoPedia: SUIT Did you know that you can measure the respiratory activity available for phosphorylation of ADP to ATP in living cells?

SUIT protocols from the SUIT-003 family will guide you through the titrations needed to analyze free ROUTINE activity.
- »SUIT-003 O2 ce D009« and »SUIT-003 O2 ce-pce D020« 
- communicated by »Cardoso Luiza« and »Komlodi Timea«

On hold

Do you know how to select the proper fluorescence sensors and filter set?

Using different fluorescence sensors, LED and photodiode filters, the O2k-Fluo Smart-Module (or O2k-Fluo LED2-Module) allows for measurement of hydrogen peroxide, ATP, mitochondrial membrane potential, calcium, and numerous other applications open for O2k-user innovation.
- »Selecting the Smart Fluo-Sensor« and »Selecting a Filter Set«