Yeast Phospholipid Research Articles

A two-dimensional thin-layer chromatographic system for phospholipid separation the analysis of yeast phospholipids

A two-dimensional thin-layer Chromatographie procedure is described for the separation of phospholipids. The first developing solvent was chloroform-methanol-acetic acid-water (52:20:7:3, by vol.). This was followed after the plates were washed with diethyl ether, by chloroform-methanol-40% aqueous methylamine-water (13:7:1:1, by vol.) in the second dimension. This procedure permitted the separation of each of the following phospholipids from one another: cardiolipin or diphosphatidyl glycerol, phosphatidyl glycerol, phosphatidic acid, phosphatidyl ethanolamine, dimethylphosphatidyl ethanolamine, phosphatidyl choline, phosphatidyl serine, phosphatidyl inositol, lysophosphatidyl ethanolamine, lysophosphatidyl choline and sphingomyelin. The method has been employed to study the phospholipid composition of log phase and stationary phase yeast. Both wild-type and respiratory-deficient yeast (cytoplasmic petite) have been studied after aerobic and anaerobic growth. Log phase yeast had more phospholipid than stationary phase yeast, particularly more phosphatidyl choline, phosphatidyl ethanolamine and phosphatidyl inositol, which are the major yeast phospholipids. Cytoplasmic respiratory deficiency did not result in any differences in these major phospholipids. The phospholipid composition of log phase yeast cells was very similar irrespective of the strain and of the presence or absence of O 2 during growth. Stationary wild-type yeast, grown anaerobically, contained less phosphatidyl choline, phosphatidyl ethanolamine and cardiolipin, and more phosphatidyl inositol than aerobically grown cells.

Phospholipids of yeast: I. Improvements in analysis by two-dimensional strip-transfer paper chromatography

1. 1. A strip-transfer technique, which enables phospholipids to be eluted from one type of paper on to a second type of paper, has resulted in improved resolution of phospholipid mixtures from yeast by two-dimensional paper chromatography. The most satisfactory separations were obtained when lipid mixtures were chromatographed in the first direction on formaldehyde-treated, alumina-impregnated, or anion exchange paper, followed by elution on to silicic acid-impregnated paper and development in the second direction. Resolution of lipid mixtures was less satisfactory when chromatography was carried out in the first direction on alumina- or silicic acid-impregnated paper, followed by development on to formaldehyde paper in the second direction. The merits of the various systems are discussed and a simple apparatus is described which facilitates the strip-transfer procedure. 2. 2. The Chromatographie methods described are particularly effective for detecting minor phospholipids (phosphatidylinositol, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylserine and N, N-dimethylphosphatidylethanolamine) in crude lipid extracts.

Phospholipids of yeast: II. Extraction, isolation and characterisation of yeast phospholipids

1. 1. The extraction of lipids from whole cells and cell preparations obtained by mechanical breakage has been investigated. The distribution patterns of phospholipids in the extracts have been determined and compared with the phospholipid pattern obtained by extracting the whole cell residue with acidified solvents. 2. 2. The isolation of pure samples of the individual phospholipids has been effected by combining preliminary column fractionations on silicic acid, alumina and DEAE-cellulose with final purifications involving chromatography on layers of silicic acid. 3. 3. A novel degradation, which permits the elimination of α-linked glycerol residues from glycerylphosphoryl derivatives has been used in structural investigations on the minor phospholipids of yeast. The structures of the following compounds have been examined: N, N-dimethylphosphatidylethanolamine, N-monomethylphosphatidylethanolamine, phosphatidylserine, phosphatidylglycerol and cardiolipin (diphosphatidylglycerol). The degradation procedure, which has been adapted for work with semi-micro quantities, yielded phosphate monoesters which were readily related to the structures of the parent phospholipids. The degradation products have been characterised by paper Chromatographic and column Chromatographic methods.