| Abstract: | 1. Monoglycosylceramide was isolated from the skin of Rana nigromaculata (Japanese pond frog), and further fractionated into three subgroups (Fraction I, Fraction II and Fraction III) by borate-impregnated Florisil column chromatography. 2. Fraction I and Fraction II contained mainly glucose as their hexose components, while Fraction III contained galactose. 3. Major long chain bases of Fraction I and Fraction III were D-erythro-1, 3-dihydroxy-2-amino-4-trans-octadecene (4-sphingenine) and D-erythro-1, 3-dihydroxy-2-aminooctadecane (sphinganine), whereas those of Fraction II were D-ribo-1, 3, 4-trihydroxy-2-aminooctadecane (4D-hydroxysphinganine) and 1, 3, 4-trihydroxy-2-aminoeicosane (C20 homologues of 4D-hydroxysphinganine). This is the first evidence of the presence of trihydroxy base-containing glycolipids in the skin of vertebrates. 4. All three subgroups of monoglycosylceramide contained both hydroxy and nonhydroxy fatty acids ranging from C14 and C26. Saturated fatty acids represented more than 90% of the total. Some differences of the fatty acid composition in the three subgroups were also observed. |
