DETERMINATION OF THE YEAST CELL pH

Abstract

Once freezing and thawing the yeast leads to incomplete destruction of the cell membrane and to too low values of the cell pH determined in the cell suspension with the glass electrode. The cells are rendered completely permeable through boiling, treatment with acetone, or freezing and thawing the cell repeatedly. Cell pH's obtained in this ways are definitely higher. The differences in cell pH's observed with completely broken cells and partly broken cells can be accounted for quantitatively to the presence of intact cells in the only once frozen and thawed cell suspension.

Interaction of ethidium bromide with yeast cells investigated by electron probe X-ray microanalysis

“…3, in which it is shown that the loss of K § is accompanied by an increasing number of cells which are stainable with the dye bromophenol blue. This dye only penetrates into leaky cells and not into intact cells [2]. The relation between the amount of K § liberated and the number of stained cells, however, is nonlinear.…”

“…With this yeast the effect of ethidium was studied only in the presence of glucose and at 30 ~ For vital staining of the cells a slightly modified procedure of Borst-Pauwels and Dobbelmann [2] was followed. A small aliquot of the suspension was diluted in 180 mM NaC1, the cells centrifuged and resuspended in 0.5 mM bromophenol blue in 45 mM Tris adjusted to pH 4.5 with succinic acid.…”

Mechanism of Resistance of Saccharomyces bailii to Benzoic, Sorbic and Other Weak Acids Used as Food Preservatives

“…After incubation, the mixtures were filtered on membrane filters and washed with 5 ml 0.1 M-KCI. The cells were scraped off, frozen and thawed 3 times in liquid N, (Borst-Pauwels & Dobbelman 1972), diluted with 25 pl 0.1 M-KCI and the pH determined using a Radiometer pH meter 22.…”

All-or-none K+ efflux from yeast cells induced by calmodulin antagonists

“…A single size-cell population was made according to [4] and sizes were measured almost immediately after dilution in 10 ml of 0.9% NaCl. Maximal K+ efflux was obtained by adding 0.1 mM cetyltrimethylammonium by which the cells become completely permeabilized [4]. Trifluoperazine and compound 48/80 were obtained from Sigma Chemie, Taufkirchen (F.R.G.)…”