Novel Neogala-Series Glycosphingolipids with a Terminal Glucose Residue from the Fungus Mariannaea elegans

Abstract

Glycosphingolipids (GSLs) are essential membrane components of eukaryotic cells. Recently, a new type of fungal neogala-series GSL was identified in aureobasidin A-resistant fungi. In this study, we analyzed GSLs from four pathogenic fungal strains belonging to the order Hypocreales, and found that Mariannaea elegans contained both acidic GSLs and neutral GSLs with mono- and di-saccharides. The structures of the neutral GSLs of M. elegans were determined by compositional sugar, fatty acid, and sphingoid analyses by GC/MS, MALDI time-of-flight/MS, and ¹H NMR. The ceramide moiety of Glcβ1-Cer consisted mainly of the 2-hydroxylated C_18:0-fatty acid 9-methyl-octadeca-4-sphinganine or 9-methyl-octadeca-4,8-sphingadienine. In contrast, the ceramides of Galβ1-6Galβ1-Cer and Glc1-6Galβ1-Cer consisted mainly of saturated 2-hydroxylated C_24:0-fatty acids and C_18:0-phytosphingosine. To our knowledge, Glc1-6Galβ1-Cer is a novel GSL in fungi, and M. elegans is the first example of an aureobasidin A-sensitive fungus that possesses fungal neogala series GSLs.