The Effects of Salicylic Acid on Metabolism and Potassium Ion Content in Yeast

Abstract

Numerous studies have shown that salicylates markedly alter metabolism, enzymic activity, and cell growth (1 -5). In both human erythrocytes (6) and molluscan neurones (7), salicylate increases the permeability of the cell membrane to K+ ion; in the latter study it was shown that salicylate simultaneously lowered the permeability to chloride ion. In the neuronal studies (7), these changes resulted in an increased potential difference across the cell membrane and the authors postulated that salicylate analgesia may result from an impaired ability of the neurone to conduct impulses along the hyperpolarized cell.The present paper deals with the metabolic and membrane effects of salicylic acid on commercial baker's yeast. While corroborating earlier studies (2) of the inhibitory effects of the compound on glucose metabolism, we present new information that salicylic acid increases endogenous fermentation and causes a leakage of K+ ions from the cells. The first and last mentioned effects are reversed by washing the cells free of salicylic acid.Methods. Experiments were done on suspensions of nongrowing baker's yeast as reported earlier (8). Suspensions were maintained at appropriate pH by use of a trissuccinate-tartrate (TST) buffer consisting of equimolar concentrations of succinic and tartaric acids adjusted to pH with tris-hydroxymethylaminomethane. With the exception of the experiment shown in Fig. 3, no K+ was added to the experiment. Any K+ found in the medium came through release of this ion by the cells. In all experiments, nitrogen gas was used to maintain anaerobic conditions and to keep suspensions from settling. K+ efflux experiments were done via a modification of the cell column technique of Rothstein and Bruce (9); in our experiments we replaced the sintered glass filters used by these investiga-tors with a 0.45-pm microfilter 47 mm in diameter. Eluting fluid was forced through the yeast column under 5-6 psi of nitrogen. Gas exchange was measured via standard manometric techniques. Experiments were conducted at 30" or 6".Estimations of glucose in diluted, filtered suspending medium were made either by means of a commercial glucose oxidase preparation (Worthington Biochemical Corp.) or the reducing sugar method of Nelson (10). Alcohol was determined quantitatively by use of a commercial alcohol dehydrogenase preparation (Worthington) and was identified as ethyl alcohol through gas chromatography.' K+ in the medium, a measure of K+ lost from the cell, was determined on filtrates of cell suspensions through direct flame photometry. Yeast concentrations are expressed in milligrams wet weight of cells per milliliter of suspension. For convenience, the total concentration of the salicylate-salicylic acid will be referred to in the text as "salicylate." Through calculation, the actual concentrations of the two species can be determined in each case from total "salicylate" concentration, the pH and the pK, of salicylic acid (3.0).Results. In Table I are shown the effects of 5 mM salicylate on glucose utilizati...

Growth inhibition of bloom-forming cyanobacterium Microcystis aeruginosa by rice straw extract

“…Tillberg (1970) found that salicylic acid at concentrations of 10 −6 –10 −3 mol l −1 (0·138–138 mg l −1 ) decreased the phosphorus uptake of the alga Scenedesmus . Meanwhile, Scharff and Perry (1976) reported that under anaerobic conditions, at a low pH and 30°C, yeast lost K + ions in the presence of salicylic acid and glucose utilization was inhibited. Thus, they concluded that a fundamental action of this compound in many organisms was to reduce the K + content in the cells.…”

Characterization of the Inhibition of K+ Absorption in Oat Roots by Salicylic Acid

“…They suggested the different results might be due to differences between species or pH of the absorption medium. Scharff and Perry (14) reported that pH of the bathing medium affects K+ efflux from yeast cells in the presence of SA. In a preliminary publication (7), we reported a similar effect of pH and SA on K+ efflux from oat roots.…”

A Versatile Transcription Factor Biosensor System Responsive to Multiple Aromatic and Indole Inducers

“…P CCW12 was engineered to be salicylate-responsive by introducing two copies of the cmeO operator sequence 11 bp downstream of the TATA box consensus sequence TATA(A/T)A(A/T)(A/G) 43 found at −133–125 nt relative to the transcription start site, thereby generating P CCW12O and the sensor strain ( Figure 2 A). Due to the toxicity of salicylate to S. cerevisiae , 44 , 45 all experiments were conducted at a lower yeast culture dilution factor and were measured after 8 h. GFP fluorescence outputs of the control and sensor strains measured by flow cytometry showed a marked drop in fluorescence upon inserting cmeO , which in turn increased by adding increasing concentrations of salicylate to the culture media, reaching up to ∼4.3-fold induction in 2.5 mM salicylate ( Figure 2 B). This data shows that, in a manner similar to our E. coli genetic circuit, CmeR functions as a transcription repressor in S. cerevisiae , and is inducible by salicylate.…”