NOVEL IMMUNOREACTIVE PHOSPHOINOSITOL CONTAINING SPHINGOLIPIDS FROM THE FUNGAL PATHOGEN HISTOPLASMA CAPSULATUM (GALACTOFURANOSE, GLYCOLIPIDS, YEAST)

Five alkali stable lipids from the yeast phase of the human pathogen Histoplasma capsulatum have been purified and analysed. Each compound has equimolar amounts of hydroxysphinganine (phytosphingosine) and a hydroxy or nonhydroxy 24:0 fatty acid. All yield inositol phosphate after acid hydrolysis and several are novel in that they also yield dimannosylinositol (compound V) and isomeric galactosyl dimannosylinositols (compounds VI and VIII). The composition and chromatographic behavior of compounds II and III indicate that they are similar to the inositolphosphoceramides previously observed in Saccharomyces cerevisiae.;Oligosaccharide.;man(,p)((alpha)1(--->)3)man(,p)((alpha)1(--->)2 or 6)myoinositol.;Oligosaccharide-VI:;Ammonolysis of compounds V, VI and VIII released all the carbohydrate (oligosaccharides-V, VI and VIII) as intact oligosaccharides suitable for characterization. Due to the unique nature of compounds V, VI and VIII, studies of sequence, linkage and anomeric configuration were initiated on the carbohydrate moieties of these lipids. Anomeric configurations were determined by specific glycosidase digestion and by the stability of peracetylated saccharides to CrO(,3) oxidation. Linkages were established by methylation analysis. The data acquired to date suggest that the structures of these compounds are: (UNFORMATTED TABLE FOLLOWS).;man(,p)((alpha)1(--->)3).;man(,p)((alpha)1(--->)2 or 6)myoinositol.;gal(,f)(1(--->)6).;Oligosaccharide-VIII:;man(,p)((alpha)1(--->)3).;man(,p)((alpha)1(--->)2 or 6)myoinositol.;gal(,p)((beta)1(--->)4).;(TABLE ENDS).;This is the first reported occurrence of galactofuranose in a glycosphingolipid. Compounds V and VI were virtually absent from the mycelial phase and compound VIII was the major alkali stable lipid of both phases. Antibodies that react with compounds V, VI and VIII have been detected in sera from patients with histoplasmosis.