Presence of glucosylceramide in yeast and its relation to alkali tolerance of yeast

Abstract

Glycosylceramide is a membrane lipid that has physiological functions in eukaryotic organisms. The presence of glucosylceramide has been confirmed in some yeast; however, the extent of the role of glucosylceramide in yeast is unknown. Thus, the extent of presence of glucosylceramide in yeast was surveyed using 90 strains of 24 genera. The strains were divided into two groups according to whether they had glucosylceramide (45 strains) or not (45 strains). The distribution of the ceramide glucosyltransferase gene (EC 2.4.1.80), which catalyzes glucosylation to a sphingoid lipid in glucosylceramide synthesis, and the phylogenetic classification of the strains were in agreement with those of glucosylceramide. Thus, the presence of glucosylceramide in yeast was caused by the presence of the gene involved in glucosylceramide synthesis and was closely associated with yeast evolution. Furthermore, the relationship between glucosylceramide presence and alkali tolerance of yeast was evaluated. The yeast with glucosylceramide tended to grow at higher pH, and a ceramide-glucosyltransferase-defective mutant from Kluyveromyces lactis did not grow at pH 8.5 even though the parent strain could grow under the same conditions. These results indicate that glucosylceramide in yeast might be a component that enables yeast to grow under alkali conditions.

In Vitro Activity of the Antifungal Plant Defensin RsAFP2 against Candida Isolates and Its In Vivo Efficacy in Prophylactic Murine Models of Candidiasis

“…1F), which is in accordance with the inability of this species to synthesize GlcCer ( Fig. 2A) (23).…”

Reconstitution of Glucosylceramide Flip-Flop across Endoplasmic Reticulum

“…The identical behavior of both NBD-PE and NBD-GlcCer flippase activity on hydroxyapatite supports our conclusion that the same flippases are responsible for flipping both lipids. (38,39), but phospholipid flippase activity has been demonstrated in yeast microsomes (19) as well as in proteoliposomes reconstituted with yeast ER membrane proteins (19,21,35). If the rat liver ER phospholipid flippases are able to translocate NBD-GlcCer, we reasoned that the same should be true in the yeast system.…”

Sphingolipids as Targets for Treatment of Fungal Infections

“…Interestingly, other virulence factor, such as capsule and melanin, are not affected in Δgcs1 mutant. Interestingly, deletion of gcs1 in C. neoformans results in a dramatic growth defect at neutral/alkaline pH, 5% CO 2 and 37°C [15], suggesting that GlcCer may be important in fungi to promote alkaline tolerance [60]. When exposed to a neutral/alkaline environment, C. neoformans cells do concentrate GlcCer at the plasma membrane/cell wall/bud necks without upregulating its synthesis [61].…”