Effects of phenethyl alcohol on yeast cells

An investigation of the physiological effects of phenethyl alcohol (PEA) on exponentially growing yeast cells is reported. RNA, DNA, protein and aminoimidazole ribotide syntheses and glucose uptake and incorporation are inhibited by PEA at concentrations of 0.1% to 0.3%. Two classes of response curves are found and the sensitivities of processes in each class to PEA differ. Glucose incorporation and RNA synthesis are the most sensitive processes in their respective classes. The effects of PEA at 0.3% or less are largely or completely reversible. It is deduced that PEA inhibits intracellular processes as well as the cell membrane.     

Nine phenethyl alcohol glycosides from Stachys sieboldii.

Three new phenethyl alcohol glycosides together with six known compounds have been isolated from the leaves of Stachys sieboldii. On the basis of chemical and spectral analyses, the structures of three new compounds named stachysosides A, B and C have been established as 2-(3,4-dihydroxyphenyl)ethyl O-alpha-L-arabinopyranosyl-(1----2)-alpha-L-rhamnopyranosyl- (1----3)-4-O-E-caffeoyl-beta-D-glucopyranoside, 2-(3,4-dihydroxyphenyl)ethyl O-alpha-L-arabinopyranosyl-(1----2)-alpha-L-rhamnopyranosyl- (1----3)-4-O-E-feruloyl-beta-D-glucopyranoside and 2-(3-hydroxy-4-methoxyphenyl)ethyl O-alpha-L-arabinopyranosyl-(1----2)-alpha-L-rhamnopyranosyl- (1----3)-4-O-E- feruloyl-beta-D-glucopyranoside, respectively.     

Effect of phenethyl alcohol and other organic substances on cellulase production

Cellulase can be produced from growth in noncellulosic substrate if the growth rate of the producing organism is restricted. Phenethyl alcohol (PEA) is a growth inhibitor and was used to control the growth of M. verrucaria in attempts to obtain increased cellulase production. Cellulase yield was found to be increased without a restriction in growth rate when PEA was present in low concentrations (0.03% v/v). The effect was observed for other organisms but notably L. trabea, which produced considerable enzyme from a small quantity of mycelium. Here increased cellulase synthesis was concomitant with restricted growth. Other chemicals with PEA-like structure (e.g. benzyl alcohol) resulted in similar or more extensive cellulase synthesis. Of the substances tried, propyl alcohol was most effective, followed by acetone. PEA causes a swelling of cell walls and inhibits spore formation. This and other data given suggest that PEA affects the cytoplasmic membrane or the cell wall or both. Cellulase synthesis is considered to take place in the membrane and wall region of the cell.     

Induction of alkaline phosphatase in Escherichia coli. Effect of phenethyl alcohol.

Induction of alkaline phosphatase, an enzyme located in the periplasmic region of Escherichia coli, was inhibited by phenethyl alcohol, an agent believed to alter the cell membrane structure. Studies to elucidate mechanism of this inhibition showed that while phenethyl alcohol arrested the incorporation of [3H]leucine into active alkaline phosphatase, it did allow substantial incorporation of the label into inactive monomer subunits of the enzyme. These results suggest that phenethyl alcohol may not interfere with the de novo synthesis of monomer subunits of the enzyme but arrest conversion of these into active dimer enzyme presumably by its primary action on the cell membrane structure.     

The effect of phenethyl alcohol on in vitro DNA synthesis in Escherichia coli.

The effect of phenethyl alcohol on DNA synthesis was examined using several in vitro systems of Escherichia coli H560; i.e., ether-treated cells, membrane fractions and folded chromosomes fortified with DNA polymerase. In all systems, the incorporation of deoxyribonucleotides was much reduced for the phenethyl alcohol-treated cells compared with the non-treated cells. The total activity of DNA polymerases in polA1 cells (mostly DNA polymerase II) was not impaired for the phenethyl alcohol-treated cells and the reduction of the rate of DNA synthesis in vitro was ascribed to the reduction of the chromosomal template activity which was related to trypsin sensitive protein components. The analysis of chromosomes from the phenethyl alcohol-treated cells revealed the remarkable reduction of a protein component of molecular weight approx. 58 000 in contrast with a protein component of molecular weight approx. 30 000.     

The inhibition of phospholipid synthesis in escherichia coli by phenethyl alcohol.

The kinetics of lipid metabolism during phenethyl alcohol treatment of Escherichia coli were examined. Phenethyl alcohol at a non-bacteriostatic concentration reduces the accumulation of [32-P] phosphate into phospholipids and alters the phospholipid composition of the cell membrane. The changes in phospholipid composition are a result of the inhibitory effect of phenethyl alcohol on the rates of synthesis of the individual phospholipids. The inhibition in the rate of phosphatidylethanolamine synthesis by phenethyl alcohol was twice the inhibition in the rate of phosphatidyglycerol synthesis. The de novo rate of cardiolipin synthesis was only slightly inhibited. However, net cardiolipin accumulation increased during phenethyl alcohol treatment due to a more rapid turnover of phosphatidylglycerol to cardiolipin. Phenethyl alcohol also altered the fatty acid composition of the cell as a result of its inhibitory effect on the rate of individual fatty acid synthesis. However, the inhibition of phospholipid synthesis was not reversed by fatty acid supplementation of phenethyl alcohol treated cells. This result indicates that phenethyl alcohol does not inhibit phospholipid synthesis solely at the level of fatty acid synthesis.     

Mechanism of bactericidal action of phenethyl alcohol inEscherichia coli

The mechanism of bactericidal action of phenethyl alcohol (PEA) inE. coli, which was previously demonstrated to be dependent on protein synthesis, has been investigated. Mutants resistant to PEA were selected, but the resistance observed was associated with a change in permeation. PEA effects on DNA, RNA, and protein synthesis were studied with bacteriostatic and bactericidal concentrations Similar results (inhibition of DNA synthesis and decrease in RNA synthesis) were obtained with lethal concentrations of PEA in cells pretreated with chloramphenicol, and with bacteriostatic concentrations of PEA in unpretreated cells. The PEA intracellular accumulation reached a maximum within 4 min and was not inhibited by KCN or by 2,4-dinitrophenol. The presence of phenylacetaldehyde was demonstrated in both stationary and exponential growth phase cells exposed to PEA but not in cells pretreated with chloramphenicol. These results suggested that the bactericidal mechanism of action of PEA involves its conversion into the corresponding aldehyde.     

Diffusion of acetophenone and phenethyl alcohol in the calcium-alginate-bakers' yeast-hexane system

The intrabead diffusion coefficients of acetophenone and phenethyl alcohol were measured at 30 degrees C in the triphasic immobilized yeast-water-hexane system. Saccharomyces cerevisiae cells were deactivated with hydrochloric acid and entrapped in calcium-alginate beads. Measurements of dry cell loss during deactivation, shrinkage of the beads during deactivation and the final porosity of the beads were made for various cell loadings. Final concentrations of wet cells in the beads ranged from approximately 0.25 to 0.30 g/mL. Mass transfer in the hexane phase, external to the beads, was eliminated experimentally. The estimated error of 5% to 10% in the diffusion coefficients is within the experimental error associated with the bead method. The effect of significant sampling volumes on the diffusivities was estimated theoretically and accounted for experimentally. The intrabead concentration of acetophenone and phenethyl alcohol was 150 to 800 ppm. The deactivated cells were shown to be impervious to acetophenone so that the measured diffusivities are extracellular parameters. The cell volume fraction in the beads ranged from 0.70 to 0.90, significantly higher than previously reported data. The effective diffusion coefficients conform to the random pore model. No diffusional interaction between acetophenone and phenethyl alcohol was observed. The addition of 2 vol% ethanol or methanol slightly increased the diffusivities. The thermodynamic partition coefficients were measured in the bead-free water-organic system and found to be an order of magnitude lower than the values calculated from the analysis of the diffusion data for the organic-bead system, suggesting that bead-free equilibrium data cannot be used in triphasic systems. (c) 1994 John Wiley & Sons, Inc.