Carbocyanine dye diS-C3(3) was repeatedly employed in monitoring the plasma membrane potential of yeast and other living cells. Four methods of measuring and evaluating probe fluorescence signal were used in different studies, based on following fluorescence parameters: fluorescence intensity emitted within a certain spectral interval, F(580)/F(560) fluorescence emission ratio, wavelength of emission spectrum maximum, and the ratio of respective fluorescence intensities corresponding to the diS-C3(3) bound to cytosolic macromolecules and remaining dissolved in the aqueous cell medium (i.e., unbound, or free). Here we show that data corresponding to the three latter spectral assessments of diS-C3(3) accumulation in cells is mutually convertible, which means that their alternative use cannot lead to ambiguities in the interpretation of the results of biological experiments. On the other hand, experiments based on the effortless measurements of fluorescence intensities should be interpreted cautiously because controversial results can be obtained, depending on the particular choice of cell-to-dye concentration ratio and emission wavelength.

• Klíčová slova
• Fluorescent probe, Plasma membrane potential, Saccharomyces cerevisiae, Spectral analysis, Yeast,
• MeSH
• fluorescenční barviva chemie   MeSH
• fluorescenční spektrometrie metody   MeSH
• karbocyaniny chemie   MeSH
• membránové potenciály * MeSH
• Saccharomyces cerevisiae chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 3,3'-dipropylthiacarbocyanine MeSH Prohlížeč
• fluorescenční barviva MeSH
• karbocyaniny MeSH

Recently we introduced a fluorescent probe technique that makes possible to convert changes of equilibrium fluorescence spectra of 3,3'-dipropylthiadicarbocyanine, diS-C3(3), measured in yeast cell suspensions under defined conditions into underlying membrane potential differences, scaled in millivolts (Plasek et al. in J Bioenerg Biomembr 44: 559-569, 2012). The results presented in this paper disclose measurements of real early changes of plasma membrane potential induced by the increase of extracellular K(+), Na(+) and H(+) concentration in S. cerevisiae with and without added glucose as energy source. Whereas the wild type and the ∆tok1 mutant cells exhibited similar depolarization curves, mutant cells lacking the two Trk1,2 potassium transporters revealed a significantly decreased membrane depolarization by K(+), particularly at lower extracellular potassium concentration [K(+)]out. In the absence of external energy source plasma membrane depolarization by K(+) was almost linear. In the presence of glucose the depolarization curves exhibited an exponential character with increasing [K(+)]out. The plasma membrane depolarization by Na(+) was independent from the presence of Trk1,2 transporters. Contrary to K(+), Na(+) depolarized the plasma membrane stronger in the presence of glucose than in its absence. The pH induced depolarization exhibited a fairly linear relationship between the membrane potential and the pHo of cell suspensions, both in the wild type and the Δtrk1,2 mutant strains, when cells were energized by glucose. In the absence of glucose the depolarization curves showed a biphasic character with enhanced depolarization at lower pHo values.

• MeSH
• buněčná membrána metabolismus   MeSH
• draslík metabolismus   MeSH
• fluorescenční barviva chemie   MeSH
• fluorometrie MeSH
• kationty jednomocné metabolismus   MeSH
• koncentrace vodíkových iontů MeSH
• membránové potenciály účinky léků   MeSH
• Saccharomyces cerevisiae účinky léků   metabolismus   MeSH
• sodík metabolismus   MeSH
• vodík metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• draslík MeSH
• fluorescenční barviva MeSH
• kationty jednomocné MeSH
• sodík MeSH
• vodík MeSH