Structure and biological functions of fungal cerebrosides

Abstract

Ceramide monohexosides (CMHs, cerebrosides) are glycosphingolipids composed of a hydrophobic ceramide linked to one sugar unit. In fungal cells, CMHs are very conserved molecules consisting of a ceramide moiety containing 9-methyl-4,8-sphingadienine in amidic linkage to 2-hydroxyoctadecanoic or 2-hydroxyhexadecanoic acids, and a carbohydrate portion consisting of one residue of glucose or galactose. 9-Methyl 4,8-sphingadienine-containing ceramides are usually glycosylated to form fungal cerebrosides, but the recent description of a ceramide dihexoside (CDH) presenting phytosphingosine in Magnaporthe grisea suggests the existence of alternative pathways of ceramide glycosylation in fungal cells. Along with their unique structural characteristics, fungal CMHs have a peculiar subcellular distribution and striking biological properties. In Pseudallescheria boydii, Candida albicans, Cryptococcus neoformans, Aspergillus nidulans, A. fumigatus, and Schizophyllum commune, CMHs are apparently involved in morphological transitions and fungal growth. The elucidation of structural and functional aspects of fungal cerebrosides may therefore contribute to the design of new antifungal agents inhibiting growth and differentiation of pathogenic species.

Cerebroside mediated elicitation of defense response in chilli (Capsicum annuumL.) againstColletotrichum capsiciinfection

“…We isolated cerebroside from F. oxysporum f. sp. lycopersici following the standard procedure of Umemura et al (2000) and Barreto-Bergter et al (2004) and it was confirmed by TLC and GC analysis. Cerebroside functions as an elicitor in a wide range of host-pathogen interactions.…”

“…Spots containing sugars appear pinkÁviolet on a white background. Cerebrosides were further purified by chromatography of latrobeads RS 2060 using elution buffer (Barreto-Bergter et al 2004) and analyzed by TLC as explained above.…”

“…Cerebrosides are neutral glycosphingolipids that contains a monosaccharide, normally glucose or galactose in 1-ortho-betaglycosidic linkage with the primary alcohol of an N-acyl sphingoid (ceramide). Since cerebrosides contain one sugar unit, they are also called ceramide monohexosides (Barreto-Bergter et al 2004). Cerebrosides were earlier extracted and purified from various fungi (Wagner and Fiegert 1969;Umemura et al 2000;Takakuwa et al 2002).…”

Sphingolipids from the human fungal pathogen Aspergillus fumigatus

“…2 β-glycosidic linkage, and is mainly composed of a 9-methyl-4,8-sphingadienine [7,11]. Although the GalCer has been reported as a minor fungal cerebroside, its relative expression seems dependent on the fungal morphotype (yeast versus mycelium) as observed in the mycopathogen Sporothrix schenckii [12].…”

“…2) [7]. The sphinganine is then N-acylated by a specific ceramide synthase, called BarA, to generate a ceramide.…”