Characterization of Sphingolipids from Mycopathogens: Factors Correlating with Expression of 2-Hydroxy Fatty Acyl (E)-3<
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- 作者：Marcos S. Toledo ; Steven B. Levery ; Anita H. Straus ; Erika Suzuki ; Michelle Momany ; John Glushka ; J. Michael Moulton ; and Helio K. Takahashi
- 刊名：Biochemistry
- 出版年：1999
- 出版时间：June 1, 1999
- 年：1999
- 卷：38
- 期：22
- 页码：7294 - 7306
- 全文大小：171K
- 年卷期：v.38,no.22(June 1, 1999)
- ISSN：1520-4995
文摘
Significant differences exist between mammals and fungi with respect to glycosphingolipid(GSL) structure and biosynthesis. Thus, these compounds, as well as the cellular machinery regulatingtheir expression, have considerable potential as targets for the diagnosis and treatment of fungal diseases.In this study, the major neutral GSL components extracted from both yeast and mycelium forms of thethermally dimorphic mycopathogen Paracoccidioides brasiliensis were purified and characterized by 1Hand 13C NMR spectroscopy, ESI-MS and ESI-MS/CID-MS, and GC-MS. The major GSLs of both formswere identified as 
-glucopyranosylceramides (GlcCer) having (4E,8E)-9-methyl-4,8-sphingadienine aslong chain base in combination with either N-2'-hydroxyoctadecanoate or N-2'-hydroxy-(E)-3'-octadecenoate. The mycelium form GlcCer had both fatty acids in a ~1:1 ratio, while that of the yeast form hadon average only ~15% of the (E)-
3-unsaturated fatty acid. Cerebrosides from two strains of Aspergillusfumigatus (237 and ATCC 9197) expressing both GalCer and GlcCer were also purified and characterizedby similar methods. The GalCer fractions were found to have ~70% and ~90% N-2'-hydroxy-(E)-3'-octadecenoate, respectively, in the two strains. In contrast, the GlcCer fractions had N-2'-hydroxy-(E)-3'-octadecenoate at only ~20 and ~50%, respectively. The remainder in all cases was the saturated 2-OHfatty acid, which has not been previously reported in cerebrosides from A. fumigatus. The availability ofdetailed structures of both glycosylinositol phosphorylceramides [Levery, S. B., Toledo, M. S., Straus, A.H., and Takahashi, H. K. (1998) Biochemistry 37, 8764-8775] and cerebrosides from P. brasiliensisrevealed parallel quantitative differences in expression between yeast and mycelium forms, as well as astriking general partitioning of ceramide structure between the two classes of GSLs. These results arediscussed with respect to possible functional roles for fungal sphingolipids, particularly as they relate tothe morphological transitions exhibited by P. brasiliensis.
-glucopyranosylceramides (GlcCer) having (4E,8E)-9-methyl-4,8-sphingadienine aslong chain base in combination with either N-2'-hydroxyoctadecanoate or N-2'-hydroxy-(E)-3'-octadecenoate. The mycelium form GlcCer had both fatty acids in a ~1:1 ratio, while that of the yeast form hadon average only ~15% of the (E)-3-unsaturated fatty acid. Cerebrosides from two strains of Aspergillusfumigatus (237 and ATCC 9197) expressing both GalCer and GlcCer were also purified and characterizedby similar methods. The GalCer fractions were found to have ~70% and ~90% N-2'-hydroxy-(E)-3'-octadecenoate, respectively, in the two strains. In contrast, the GlcCer fractions had N-2'-hydroxy-(E)-3'-octadecenoate at only ~20 and ~50%, respectively. The remainder in all cases was the saturated 2-OHfatty acid, which has not been previously reported in cerebrosides from A. fumigatus. The availability ofdetailed structures of both glycosylinositol phosphorylceramides [Levery, S. B., Toledo, M. S., Straus, A.H., and Takahashi, H. K. (1998) Biochemistry 37, 8764-8775] and cerebrosides from P. brasiliensisrevealed parallel quantitative differences in expression between yeast and mycelium forms, as well as astriking general partitioning of ceramide structure between the two classes of GSLs. These results arediscussed with respect to possible functional roles for fungal sphingolipids, particularly as they relate tothe morphological transitions exhibited by P. brasiliensis.