Electrochemical detection of intracellular and cell membrane redox systems in Saccharomyces cerevisiae

Abstract

Redox mediators can interact with eukaryote cells at a number of different cell locations. While cell membrane redox centres are easily accessible, the redox centres of catabolism are situated within the cytoplasm and mitochondria and can be difficult to access. We have systematically investigated the interaction of thirteen commonly used lipophilic and hydrophilic mediators with the yeast Saccharomyces cerevisiae. A double mediator system is used in which ferricyanide is the final electron acceptor (the reporter mediator). After incubation of cells with mediators, steady state voltammetry of the ferri/ferrocyanide redox couple allows quantitation of the amount of mediator reduced by the cells. The plateau current at 425 mV vs Ag/AgCl gives the analytical signal. The results show that five of the mediators interact with at least three different trans Plasma Membrane Electron Transport systems (tPMETs), and that four mediators cross the plasma membrane to interact with cytoplasmic and mitochondrial redox molecules. Four of the mediators inhibit electron transfer from S. cerevisiae. Catabolic inhibitors were used to locate the cellular source of electrons for three of the mediators.

Electronic control of gene expression and cell behaviour in Escherichia coli through redox signalling

“…Conversely, BESs aim to electrochemically intercede with microbial metabolism for the production of various compounds of interest1516. Electronic interrogation of biological systems with redox molecules has allowed for detection of changes in cell metabolic activity171819, redox state202122, toxicity23 and other parameters4. Cells have been engineered for enhanced electron flow2425 and to allow for electronic detection of engineered cell activity2627.…”

Mediated electrochemical method for the analysis of membrane damage effects of phenolic compounds to Staphylococcus aureus

“…Recently, mediated electrochemical methods have been used for several potential applications, such as biotoxicity assessment, biochemical oxygen demand assay, and even for the controlled release property of β-cyclodextrin [9][10][11][12][13][14][15][16][17][18]28]. This method is characterized by high levels of microorganisms and mediator in order to facilitate the reaction.…”

“…4 curves b and c show that the steady-state voltammograms of ferrocyanide accumulations obtained after 2 h incubation of the bacterium with glucose and ferricyanide (or DCPIP-ferricyanide system) mixture have shifted up the current axis and there is both anodic current (arising from oxidation of ferrocyanide) and cathodic current (arising from reduction of ferricyanide). The steady-state anodic plateau current measured at E = 500 mV was used as a relative measure of the amount of ferrocyanide produced, which is related to the physiological status of the bacteria [15]. The controlled experiment has also been performed in the absence of cells and confirmed that the reduction of ferricyanide does not happen if only the monosaccharide glucose and ferricyanide are present in the incubation solutions.…”

“…Ferrocyanide accumulations arising from the above cycle was assayed by microelectrode voltammetric measurements. dissolved in 96% ethanol to obtain a 20 mM solution, which was filtered, sterilized, and stored in a light-proof container at 4°C [15].…”

“…The changes in the redox state of the cells indicate the occurrence of electron transport in the biological system and modification in the physiological state of the living cells [14][15][16]. The electrochemical studies of redox state of living cells might be useful in monitoring different pathophysiological states of the cells, such as oxidative and nutrient stresses, effect of cytotoxic, mutagenic, and carcinogenic preparations [17][18][19].…”