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

This review summarizes the main results obtained in the fields of general and molecular microbiology and microbial genetics at the Institute of Microbiology of the Academy of Sciences of the Czech Republic (AS CR) [formerly Czechoslovak Academy of Sciences (CAS)] over more than 50 years. Contribution of the founder of the Institute, academician Ivan Málek, to the introduction of these topics into the scientific program of the Institute of Microbiology and to further development of these studies is also included.

• MeSH
• akademie a ústavy dějiny   MeSH
• dějiny 20. století MeSH
• mikrobiální genetika dějiny   MeSH
• molekulární biologie dějiny   MeSH
• Check Tag
• dějiny 20. století MeSH
• Publikační typ
• časopisecké články MeSH
• historické články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Geografické názvy
• Česká republika MeSH

The long-term action of recommended (RC) and near-recommended concentrations of several commercial biocides (Lonzabac 12.100, Genamin CS302D, benzalkonium chloride and 2-phenoxyethanol) on cells of S. cerevisiae wild-type strain DTXII was described using plating tests while short-term effects were determined using the potentiometric fluorescent probe diS-C3(3) that detects both changes in membrane potential and impairment of membrane integrity. A 2-d plating of cells exposed to 0.5xRC of benzalkonium chloride and Genamin CS302D for 15 min showed a complete long-term cell killing, with 2-phenoxyethanol the killing was complete only at 2xRC and Lonzabac caused complete killing at RC but not at 0.5xRC. The diS-C3(3) fluorescence assay performed immediately after a 10-min biocide exposure revealed several concentration-dependent modes of action: Lonzabac at 0.5xRC caused a mere depolarization, higher concentrations causing gradually increasing cell damage; benzalkonium chloride and Genamin CS302D rapidly damaged the membrane of some cells and depolarized the rest whereas 2-phenoxyethanol, which had the lowest effect in the plating test, produced a concentration-dependent fraction of cells with impaired membranes. Cell staining slightly increased during the diS-C3(3) assay; addition of a protonophore showed that part of the remaining undamaged cells retained their membrane potential. Comparison of short-term and long-term data implies that membrane depolarization alone is not sufficient for complete long-term killing of yeast cells under the action of a biocide unless it is accompanied by perceptible impairment of membrane integrity. The results show that the diS-C3(3) fluorescence assay, which reflects the short-term effects of a biocide on cell membranes, can be successfully used to assess the microbicidal efficiency of biocides.

• MeSH
• antiinfekční látky farmakologie   MeSH
• benzalkoniové sloučeniny farmakologie   MeSH
• buněčná membrána účinky léků   MeSH
• ethylenglykoly farmakologie   MeSH
• fluorescenční barviva metabolismus   MeSH
• fluorescenční spektrometrie MeSH
• karbocyaniny metabolismus   MeSH
• membránové potenciály účinky léků   MeSH
• mikrobiální testy citlivosti metody   MeSH
• permeabilita buněčné membrány účinky léků   MeSH
• Saccharomyces cerevisiae účinky léků   růst a vývoj   MeSH
• Publikační typ
• časopisecké články MeSH
• hodnotící studie MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 3,3'-dipropylthiacarbocyanine MeSH Prohlížeč
• antiinfekční látky MeSH
• benzalkoniové sloučeniny MeSH
• ethylenglykoly MeSH
• fluorescenční barviva MeSH
• karbocyaniny MeSH
• phenoxyethanol MeSH Prohlížeč

Evaluation of emission spectra of fluorescent probes used for the monitoring of membrane potential in microbial cells can be greatly facilitated by using synchronously excited spectroscopy (SES). This method permits the suppression of undesirable spectrum components (contributions due to scattered light or cell autofluorescence) and leads to considerable increase in monitored emission intensity and to narrowing of spectral peaks. It allows an efficient fractional decomposition of the probe fluorescence spectra into their free and bound dye fluorescence components. The usefulness of the method was tested by monitoring the accumulation of the fluorescent membrane potential probe diS-C3(3) in yeast cells, which serves as a qualitative measure of the membrane potential.

• MeSH
• fluorescenční barviva metabolismus   MeSH
• fluorescenční spektrometrie metody   MeSH
• karbocyaniny metabolismus   MeSH
• membránové potenciály fyziologie   MeSH
• Saccharomyces cerevisiae fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH
• hodnotící studie MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 3,3'-dipropylthiacarbocyanine MeSH Prohlížeč
• fluorescenční barviva MeSH
• karbocyaniny MeSH

The rate and extent of uptake of the fluorescent probe diS-C3(3) reporting on membrane potential in S. cerevisiae is affected by the strain under study, cell-growth phase, starvation and by the concentration of glucose both in the growth medium and in the monitored cell suspension under non-growth conditions. Killer toxin K1 brings about changes in membrane potential. In all types of cells tested, viz. in glucose-supplied stationary or exponential cells of the killer-sensitive strain S6/1 or a conventional strain RXII, or in glucose-free exponential cells of both strains, both active and heat-inactivated toxin slow down the potential-dependent uptake of diS-C3(3) into the cells. This may reflect "clogging" of pores in the cell wall that hinders, but does not prevent, probe passage to the plasma membrane and its equilibration. The clogging effect of heat-inactivated toxin is stronger than that exerted by active toxin. In susceptible cells, i.e. in exponential-phase glucose-supplied cells of the sensitive strain S6/1, this phase of probe uptake retardation is followed by an irreversible red shift in probe fluorescence maximum lambda max indicating damage to membrane integrity and cell permeabilization. A similar fast red shift in lambda max signifying lethal cell damage was found in heat-killed or nystatin-treated cells.

• MeSH
• fluorescenční barviva metabolismus   MeSH
• fungální proteiny farmakologie   MeSH
• karbocyaniny metabolismus   MeSH
• killer faktory kvasinek MeSH
• membránové potenciály účinky léků   MeSH
• mykotoxiny farmakologie   MeSH
• nystatin farmakologie   MeSH
• Saccharomyces cerevisiae fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 3,3'-dipropylthiacarbocyanine MeSH Prohlížeč
• fluorescenční barviva MeSH
• fungální proteiny MeSH
• K1 killer toxin MeSH Prohlížeč
• karbocyaniny MeSH
• killer faktory kvasinek MeSH
• mykotoxiny MeSH
• nystatin MeSH