Lipids of Candida Utilis: Changes With Growth

Abstract

Total lipids were extracted from cells of Candida utilis grown in batch, chemostat, and phased culture. Thin-layer chromatography of the extracts showed qualitative changes in the different lipid classes with growth. Gas–liquid chromatography was used to follow quantitative changes in the fatty acid constituents. Changes were found to be analogous to those previously reported for the amino acid pool, i.e., characteristic of the medium, of growth rate, and of the environment. The significance of the changes, and of the methods used to detect them, are discussed in relation to the growth and metabolism of the cell and of the culture.

Mode of Action of the Polyene Antibiotic Candicidin: Binding Factors in the Wall of Candida albicans

“…Standard yeast suspensions made of C. albicans cells known to be in the logarithmic growth phase (yeasts harvested 6 h after inoculation into SDB) and a similar suspension of yeasts known to be in the stationary phase (harvested 18 h after inoculation into SDB) were prepared in 0.025 M DMG, pH 6.0. The potassium efflux on treatment with 25 ,ug of candicidin per ml at 20 C was followed with a potassium-sensitive electrode.…”

“…The lipid composition of yeasts is very susceptible to variations in growth conditions (17). Several workers have observed changes in the lipid composition, notably in the total amount of lipid, the degree of lipid saturation, and the relative proportions of different phospholipids during growth (4,6,16,18). Total yeast lipid and degree of unsaturation are affected by deficiency of nitrogen, phosphate, or carbon source and changes in 02 tension or temperature.…”

“…Approximately 106 cells from a maintenance slope of C. albicans NCTC 713 grown on Sabouraud dextrose agar (Oxoid Ltd., London) for 24 h at 37 C, and stored at 4 C, were transferred to 100 ml of prewarmed sterile Sabouraud dextrose broth (SDB) (Oxoid Ltd.) in a 300-ml Erlenmeyer flask fitted with a loose cottonwool plug and incubated at 37 C in shake culture to ensure aerobic growth. At set time intervals the yeast was harvested by centrifugation (MSE 18, Croydon; 10,000 x g for 10 6.0, to giveE,21 = 1.0 (Cecil 304 spectrophotometer, Cecil Instruments Ltd., Cambridge). Such suspensions were found to contain 3.7 x 107 yeasts/ml (total hemocytometer count), and on drying to constant weight at 105 C they contained 0.92 mg (dry weight)/ml.…”

Changes in the Lipid Composition of Candida utilis during the Cell Cycle

“…More recently, Cejkovii & Jirkh (1978) claimed that cell division in a strain of Saccharomyces cerevisiae induced an increase in sterol content, although these workers too did not separate free and esterified sterols. The present paper reports further changes in lipid composition during the cell cycle of the strain of C. utilis used by Dawson & Craig (1966). By using an automatic phasing technique for obtaining synchronously dividing cultures, large crops of organisms could be analysed.…”

“…Most of the techniques used to obtain synchronously dividing cultures produce relatively small populations of organisms and this has been an impediment to studies, such as following changes in lipid composition (Rattray et al, 1975), which require larger quantities of cell material. Dawson & Craig (1966) were the first to report on changes in lipid composition during a yeast cell cycle, when they showed that, in nitrogen-limited Candida utilis, oscillations occurred in the contents of the major fatty-acyl residues. Later, Penman & Duffus (1976) described a continuous and exponential pattern of accumulation of total ergosterol (free and esterified) and phospholipids during the cell cycle of Kluyveromyces fragilis.…”