Effects of medium pH on the yeast plasma membrane potential

• Published in: Archives of biochemistry and biophysics 2024-10, Vol.760, p.110131, Article 110131
• Main Authors: Peña, Antonio, Sánchez, Norma Silvia, Ramiro-Cortés, Yazmín, Calahorra, Martha
• Format: Article
• Language: English
• Subjects: Cell Membrane - chemistry; Cell Membrane - metabolism; Culture Media - chemistry; Hydrogen-Ion Concentration; Ion transport; Membrane potential indicators; Membrane Potentials - physiology; Plasma membrane potential; Potassium - metabolism; Saccharomyces cerevisiae - metabolism; Thioflavin T; Yeast
• ISSN: 0003-9861; 1096-0384; 1096-0384
• DOI: 10.1016/j.abb.2024.110131

The effects of different pH incubation values and K+ on yeast plasma membrane potential (PMP) were studied both by the fluorescence changes and the accumulation of thioflavin T (ThT), a method that has been shown most adequate for both procedures. By the changes in fluorescence of ThT, the qualitative observation of PMP at the 3 evaluated pHs indicated that cells at pH 4.0 maintain a PMP lower, but close to the observed at pH 6.0 and 7.0. By measuring the accumulation of ThT and applying the Nernst equation on the different concentrations in and out, the values of PMP could also be estimated at the different pHs, resulting in values in mV, in agreement with our observations by following the fluorescence. Yeast cells at their native niches, or during fermentations must cope with low pHs, so the importance to maintain a robust PMP to survive. The contribution of bicarbonate, derived from the fermentation to the establishment of the PMP is also described. The experiments showed once more the efficacy of the methods used with this dye. [Display omitted] •Yeast Plasma Membrane Potential (PMP) was estimated by the accumulation of Thioflavin T.•Significant PMP values were found at low pH.•Bicarbonate from fermentation contributes to the yeast PMP.•Yeast keep robust PMP at low pH to survive in natural environments.