文摘
It is considered that all growing cells, for exception of acidophilic bacteria, have negatively charged inside cytoplasmic membrane (Δψ?/sup> - cells). Here we show that growing populations of microbial cells contain a small portion of cells with positively charged inside cytoplasmic membrane (Δψ+ - cells). These cells were detected after simultaneous application of the fluorescent probes for positive membrane potential (anionic dye DIBAC-) and membrane integrity (propidium iodide, PI). We found in exponentially growing cell populations of Escherichia coli and Saccharomyces cerevisiae that the content of live Δψ- - cells was 93.6?±-.8?% for bacteria and 90.4?±-.0?% for yeasts and the content of live Δψ+ - cells was 0.9?±-.3?% for bacteria and 2.4?±-.7?% for yeasts. Hypothetically, existence of Δψ+ - cells could be due to short-term, about 1?min for bacteria and 5?min for yeasts, change of membrane potential from negative to positive value during the cell cycle. This change has been shown by the reversions of K+, Na+, and Ca2+ ions fluxes across the cell membrane during synchronous yeast culture. The transformation of Δψ-- cells to Δψ+ - cells can be explained by slow influx of K+ ions into Δψ-- cell to the trigger level of K+ concentration (“compression of potassium spring-, which is forming “alternative-Δψ+-cell for a short period, following with fast efflux of K+ ions out of Δψ+-cell (“release of potassium spring- returning cell to normal Δψ- state. We anticipate our results to be a starting point to reveal the biological role of cell dualism in form of Δψ- - and Δψ+ - cells.