Glycobiology, 2001, Vol. 11, No. 2 113-124
© 2001 Oxford University Press
Characterization of cerebrosides from the thermally dimorphic mycopathogen Histoplasma capsulatum: expression of 2-hydroxy fatty N-acyl (E)-
3-unsaturation correlates with the yeast–mycelium phase transition
Department of Biochemistry, Universidade Federal de São Paulo/Escola Paulista de Medicina, Rua Botucatu 862, 04023–900, São Paulo, SP, Brasil, and 2The Complex Carbohydrate Research Center and Department of Biochemistry and Molecular Biology, University of Georgia, 220 Riverbend Road, Athens, GA 30602–7229, USA
Cerebroside (monohexosylceramide) components were identified in neutral lipids extracted from both the yeast and mycelial forms of the thermally dimorphic mycopathogen Histoplasma capsulatum. The components were purified from both forms and their structures elucidated by 1- and 2-dimensional nuclear magnetic resonance (NMR) spectroscopy, electrospray ionization mass spectrometry (ESI-MS), and low energy tandem collision-induced dissociation mass spectrometry (ESI-MS/CID-MS). Both components were characterized as ß-glucopyranosylceramides (GlcCers) containing (4E,8E)-9-methyl-4,8-sphingadienine as the long-chain base, attached to 18-carbon 2-hydroxy fatty N-acyl components. However, while the fatty acid of the yeast form GlcCer was virtually all N-2'-hydroxyoctadecanoate, the mycelium form GlcCer was characterized by almost exclusive expression of N-2'-hydroxy-(E)-
3-octadecenoate. These results suggest that the yeast—mycelium transition is accompanied by up-regulation of an as yet uncharacterized ceramide or cerebroside 2-hydroxy fatty N-acyl (E)-3-desaturase activity. They also constitute further evidence for the existence of two distinct pathways for ceramide biosynthesis in fungi, since glycosylinositol phosphorylceramides (GIPCs), the other major class of fungal glycosphingolipids, are found with ceramides consisting of 4-hydroxysphinganine (phytosphingosine) and longer chain 2-hydroxy fatty acids. In addition to identification of the major glucocerebroside components, minor components (<5%) detectable by molecular weight differences in the ESI-MS profiles were also characterized by tandem ESI-MS/CID-MS analysis. These minor components were identified as variants differing in fatty acyl chain length, or the absence of the sphingoid 9-methyl group or (E)-8-unsaturation, and are hypothesized to be either biosynthetic intermediates or the result of imperfect chemical transformation by the enzymes responsible for these features. Possible implications of these findings with respect to chemotaxonomy, compartmentalization of fungal glycosphingolipid biosynthetic pathways, and regulation of morphological transitions in H.capsulatum and other dimorphic fungi are discussed.
1 To whom correspondence should be addressed
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  S. T. Pruett, A. Bushnev, K. Hagedorn, M. Adiga, C. A. Haynes, M. C. Sullards, D. C. Liotta, and A. H. Merrill Jr. Thematic Review Series: Sphingolipids. Biodiversity of sphingoid bases ("sphingosines") and related amino alcohols J. Lipid Res., August 1, 2008; 49(8): 1621 - 1639. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. Rhome, T. McQuiston, T. Kechichian, A. Bielawska, M. Hennig, M. Drago, G. Morace, C. Luberto, and M. Del Poeta Biosynthesis and Immunogenicity of Glucosylceramide in Cryptococcus neoformans and Other Human Pathogens Eukaryot. Cell, October 1, 2007; 6(10): 1715 - 1726. [Full Text] [PDF]
|
|
|
|
 |
|
 E. Arigi, S. Singh, A. H Kahlili, H. C Winter, I. J Goldstein, and S. B Levery Characterization of neutral and acidic glycosphingolipids from the lectin-producing mushroom, Polyporus squamosus Glycobiology, July 1, 2007; 17(7): 754 - 766. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. J. Heung, C. Luberto, and M. Del Poeta Role of Sphingolipids in Microbial Pathogenesis Infect. Immun., January 1, 2006; 74(1): 28 - 39. [Full Text] [PDF]
|
|
|
|
|
|
C. Park, B. Bennion, I. E. J. A. Francois, K. K. A. Ferket, B. P. A. Cammue, K. Thevissen, and S. B. Levery Neutral glycolipids of the filamentous fungus Neurospora crassa: altered expression in plant defensin-resistant mutants J. Lipid Res., April 1, 2005; 46(4): 759 - 768. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. Thevissen, D. C. Warnecke, I. E. J. A. Francois, M. Leipelt, E. Heinz, C. Ott, U. Zahringer, B. P. H. J. Thomma, K. K. A. Ferket, and B. P. A. Cammue Defensins from Insects and Plants Interact with Fungal Glucosylceramides J. Biol. Chem., February 6, 2004; 279(6): 3900 - 3905. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. R. Pinto, M. L. Rodrigues, L. R. Travassos, R. M. T. Haido, R. Wait, and E. Barreto-Bergter Characterization of glucosylceramides in Pseudallescheria boydii and their involvement in fungal differentiation Glycobiology, April 1, 2002; 12(4): 251 - 260. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Leipelt, D. Warnecke, U. Zahringer, C. Ott, F. Muller, B. Hube, and E. Heinz Glucosylceramide Synthases, a Gene Family Responsible for the Biosynthesis of Glucosphingolipids in Animals, Plants, and Fungi J. Biol. Chem., August 31, 2001; 276(36): 33621 - 33629. [Abstract] [Full Text] [PDF]
|
|