Bioenergetics: Open Access

Redox State and Mitochondrial Respiration are regulated by Coenzyme Q Redox State in Isolated Mitochondria

Timea Komlodi^* Biochemistry and Medicine, School of Life Sciences, Univ Sussex, Falmer, Brighton, UK
^*Correspondence: Timea Komlodi, Biochemistry and Medicine, School of Life Sciences, Univ Sussex, Falmer, Brighton, UK, Email:

Published: 26-Nov-2021

Introduction

Mitochondrial function is known to be an important factor in maintaining cellular homeostasis and its dysregulation has become a hallmark for multiple disease conditions. This review aims to synthesise the extent of this knowledge by analysing changes of mitochondrial physiology parameters in Parkinson’s disease (PD) and to evaluate the contribution of cellular models of PD in the field. The analysis provided here constitutes a platform for further elucidation of mitochondrial function parameters relative to factors that may potentiate disease progression.

For the advanced study of mitochondrial function, high-resolution respirometry is extended by fluorometric measurement of ATP production using the fluorophore Magnesium Green (MgG). A common problem with several fluorescent dyes is the inhibition of mitochondrial respiration. In the present study, a coupling control protocol was applied in combination with MgG to measure ATP production simultaneously with respiration for calculation of ratios. MgG at 1 µM did not affect respiration through the NADH-linked and succinate-linked pathways. Respiration was not inhibited in any of the coupling control states, hence coupling control efficiencies were not affected by MgG.

Launching and maintaining a scientific journal must be reflected and communicated with a message at a time of excessive numbers of research papers submitted to for-profit publishers of traditional paywall and predatory journals. Bioenergetics Communications BEC supports the UNESCO recommendation on Open Science and DORA. BEC introduces the concept of Living Communications to address the conflict between (R) rapid sharing of new methods and results, (E) efficient prevention of exponentially increasing numbers of publications, and (C) quality control as a time-demanding and expensive instrument to ensure reproducibility. Weekly or monthly printed issues are yesterday’s concept of prescription journals replaced by commonly and immediately accessible formats in the digital era of Open Access online publishing. The academic publishing ecosystem must be changed to re-allocate publication fees from publishers to science producers.

We analysed the medium specificity of the background fluorescence slope of the AmR assay, the oxygen dependence of flux in baker´s yeast Saccharomyces cerevisiae. Apparent flux, concentration, and flux were measured simultaneously by high-resolution respirometry equipped with the fluorescence module. The apparent flux of yeast showed a maximum under hypoxia when incubated in Dulbecco´s Phosphate Buffered Saline DPBS or KCl-medium. This hypoxic peak increased with the sequential number of normoxic-anoxic transitions. Even in the absence of yeast, the fluorescence slope increased at low levels as a function of fluorescence intensity. The hypoxic peak was not observed in mitochondrial respiration medium MiR05. Therefore, the hypoxic peak was a medium-specific background effect unrelated to cell physiology. In MiR05, production of yeast decreased linearly from hyperoxia to hypoxia, with a steep decline towards anoxia. Respiration and oxygen dependence expressed as p50 of yeast were higher in MiR05 than DPBS. Respiration was a hyperbolic function of oxygen concentration in the low-oxygen range. The flux-dependence of oxygen affinity explained the higher p50 in MiR05.