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Difference between revisions of "Talk:Amplex UltraRed"

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== Media ==
See [[Krumschnabel 2015 Methods Mol Biol]], [[Tretter 2012 Free Radic Biol Med]], [[Komary 2010 Biochim Biophys Acta]].
Media with high antioxidant activity compete with HRP and partially consume H<sub>2</sub>O<sub>2</sub> before it can react with Amplex (R) (Ultra)Red  to form the active fluorophore resorufin. This was shown by comparing 
* the sensitivity as determined by H<sub>2</sub>O<sub>2</sub> additions to different media containing HRP and Amplex (R) UltraRed;
* the sensitivity as determined by addition of the actual fluorophore resorufin to the same media (signal change per added resorufin); the sensitivity is signal change per added H<sub>2</sub>O<sub>2</sub> or resorufin.
The sensitivity, as determined by addition of H<sub>2</sub>O<sub>2</sub>, is much higher in a simple phosphate buffer compared to media with strong antioxidant capacity. In contrast, this is not the case for the sensitivity with respect to resorufin.
A chemical background drift, which is always observed for the Amplex /HRP system, is independent of the H<sub>2</sub>O<sub>2</sub> sensitivity versus the same (absolute) drift expressed as (calibrated)  "apparent H2O2 production" will be higher in a medium with low H2O2  sensitivity as compared to a medium with high H2O2 sensitivity.
As  expected some traditional KCl based media, similar to those used in  ... showed a far higher sensitivity against H2O2 addition than MiR05, while some experiments indicated a lower respiration.


=== Comparison MiR05Cr to MiRK03Cr ===
=== Comparison MiR05Cr to MiRK03Cr ===

Revision as of 19:17, 6 February 2016


Comparison MiR05Cr to MiRK03Cr

Instrumental settings

  • Amp. Gain 1000
  • Light intesity variable: 1 mA, 2 mA and 5 mA
  • Configuration O2k-Fluo sensor always the same: O2k P1: Sensors B-0111/B-0082; O2k P2: Sensors B-0119/B-0117; O2k P3: Sensors A-0004/B-0112; O2k P4: Sensors A-0087/A-0088.

Media

  • MiR05Cr
  • MiRK03Cr: KCl 130 mM, HEPES free acid 20 mM, KH2PO4 10 mM, MgCl2 3 mM, EGTA 0.5 mM, BSA 0.1%, pH=7, add 120 mg Creatine to 40 ml buffer. After thawing MiRK03 a preciptate was observed, which was dissolved after 20 min shaking.

Titrations

  • 10 µl Amplex UltraRed (stock: 1 mM -> 5 µM final in chamber)
  • 4 µl HRP (stock: 500 U/ml -> 1 U/ml final in chamber)
  • 2*10 µl of 56,32 µM H2O2 solution

Results/Figures

Drift vs Sensitivity:

Drift vs sensitivity.png

Fig.6

SD drift at diff. H2O2 conc.png

Fig.7


--> Drift and sensitivity at least as good as MitoOx2 (=MiRK02)


Drift vs light intensity

Light int. vs. calib.drift in MiR05Cr.png Light int. vs.calib. drift in MiRK03Cr.png

Fig.14 and Fig. 15


--> MirK03, MiR05: drift not dependent on light intensity ( 1 to 5 mA)

compare to "MitoOx2":

Drift vs light MitoOx2.png

Evaluation of respirometry in MiR05Cr versus MiRK03Cr (N=2):

Titrations

  • 10 µl Amplex UltraRed (stock: 1 mM -> 5 µM final in chamber)
  • 4 µl HRP (stock: 500 U/ml -> 1 U/ml final in chamber)
  • 2*5 µl of 28.16 µM H2O2 solution : 0 µM, 0.07040 µM, 0.1406 µM

O2 Flux per mass MiR05Cr vs MiRK03Cr.png Flux Control Ratio MiR05Cr vs MiRK03Cr.png

Fig.16 and 17


Drift signal ratios.png

Fontanam 16:22, 6 August 2013 (CEST)


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