Talk:Permeabilized muscle fibers
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Revision as of 11:00, 24 March 2012 by Gnaiger Erich (talk | contribs)
Are permeabilized fibres a valid model?
Carful planning
- We are struggling with the issue of what oxygen concentration to use with our permeabilized muscle fibers. I know from Leslie who attended the workshop last December that you are recommending high oxygen concentrations. However, much of the published work (eg Neufer's work) was done at normal oxygen partial pressure. Also, the work of Wilson and others suggests that intramitochondrial oxygen concentration is usually very low and that OXPHOS is very sensitive to oxygen concentration. I'm concerned about the ability to compare to the current literature and the physiological relevance of using these higher oxygen concentrations. We're also looking at other measures (H2O2 production) using a setup that currently does not allow us to do these measures at higher oxygen concentrations and would not be able to relate these results to mito function if we use high O2 for the respirometry. Any thoughts?? (2012-03-20)
- This question added to the initiation of the Bioblast alert 2012(3) discussion.
- I can certainly see your argument about O2 saturation, but this may not be physiological. With the O2k-Fluorescence Module I can at least do the ROS assay under the exact conditions of the respirometry. I’ll need to ponder the question of preparation and O2 concentration further. One consideration is that I am comparing subjects before and after an intervention so changes could be meaningful as long I am consistent about conditions. I will definitely need to discuss the caveat that it may not reflect physiological conditions no matter how I do it. I’ll take a look at the PBI-Shredder information. Again, I really appreciate your input and will look at the references and workshop info more carefully before I decide which way to go.
- Irene Schauer - MiPNet Lab US (2012-03-23)
Unquestionable: Pfi are a well tested and highly useful model
- I am not surprised with your conclusion at this stage that Pfi may not provide an optimum model for studies of ROS production especially because we have to work with such high 02 levels. But without doubt, Pfi experiments have a great value to predict athletic abilities, to detect subclinical myopathies and recently, I had convincing results in horses confirmed for a genetic defect causing exertional myopathies. A most interesting aspect was that (1) we get these results before the conformation of the genetic disorder, and (2) for one of these horses (with a history of exercise intolerance), the “standard” exercise test did not reveal the existing myopathy. With the numerous trials performed with HRR on Pfi, I became convinced of the usefulness of Pfi and HRR but we have to be careful with respect to the purpose of the experiments we do.
- Dominique Votion - MiPNet Lab BE (2012-03-23)
Add to the discussion
- I have gone to the Bioblast page and read with interest the posting about the applicability of permeabilized myofibers for ROS measurements. One thing I would like to know is if there is room for a response on the Bioblast page? In particular, we have found that mitochondrial isolation markedly potentiates mitochondrial ROS generation relative to permeabilized myofibers (Picard et al., PLoS One 2011). As such, I would be interested to know how the ROS production in the mitochondria obtained using the PBI-Shredder compares to that observed in permeabilized myofibers before concluding either way whether this newer method is superior to permeabilized myofibers.
- Russel. T. Hepple - MiPNet Lab CA (2012-03-23)
