Yeast sterol esters and their relationship to the growth of yeast

Abstract

Variation in the percentage of sterols esterified to long-chain fatty acids during cellular growth has been examined. Under all conditions, a constant percentage of sterol esters was maintained during exponential growth. This maintenance level was found to vary with different growth conditions. A sharp increase in the rate of esterification was observed upon entry of the culture into the stationary growth phase. The minor cellular sterol components were found to accumulate after this period of rapid sterol ester synthesis, with a relative decrease in the size of the ergosterol pool. Evidence is presented that sterol esters of ergosterol precursors are unable to be metabolized to ergosterol. Once esterified, the fatty acids do not appear to be scavenged during starvation conditions.

Fatty Acid Composition in Ergosteryl Esters and Triglycerides from the Fungus Ganoderma lucidum

“…The d 13 C values are the means of three determinations, and have their typical standard deviations were less than 0.3 % J Am Oil Chem Soc (2013) 90:1495-1502 1499 the secondary fatty acids in ergosteryl esters from G. lucidum. It has been reported that the principal fatty acids of steryl esters in yeast were C 16 and C 18 unsaturated fatty acids [8]. Ferreira et al [17] indicated that saturated fatty acids cannot be efficiently stored within steryl esters and suggested that the absence of sterol moieties as saturated fatty acid counterparts for steryl ester synthesis can be accounted for by ergosterol biosynthesis shutdown.…”

“…Although it was reported that the prevailing fatty acids in ergosteryl esters were C 16 and C 18 unsaturated fatty acids in yeast [8], little was known of the prevalent fatty acids in ergosteryl esters and triglycerides in G. lucidum. In the present study, the fatty acid compositions and stable carbon isotope ratios of the dominant fatty acids in ergosteryl esters and triglycerides from G. lucidum were studied.…”

Effect of exogenous fatty acids on growth, membrane fluidity, and phospholipid fatty acid composition in yeast

“…Concentration of both appears to be dependent on growth conditions. The content of steryl esters in cells growing exponentially on glucose, conditions similar to those we employed, is insignificant and ranges from 0%-10% of total sterol content [13]. The level of triglycerides, while quite high in anaerobically grown cells [15], amounted to less than 10% of that of phospholipids in cells grown at 30°C in chemostat cultures [16], and it has been suggested that triglycerides accumulate only in the stationary phase of growth [ 171.…”

An essential fungal growth factor derived from ergosterol: A new end product of sterol biosynthesis in fungi?

“…Tests for contaminating sterols in the aqueous extract (III) included methanolic pyrogallol saponification (5) and treatment with dimethyl sulfoxide (Me2SO) (7). Both saponified and Me2SO SERF samples were extracted into n-hexane and evaporated to dryness with N2 and gentle heating.…”