Navegando por Palavras-chave "electrospray ionization"

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    Analysis of glycosylinositol phosphorylceramides expressed by the opportunistic mycopathogen Aspergillus fumigatus
    (Amer Soc Biochemistry Molecular Biology Inc, 2007-08-01) Toledo, Marcos S. [UNIFESP]; Levery, Steven B.; Bennion, Beau; Guimaraes, Luciana L. [UNIFESP]; Castle, Sherry A.; Lindsey, Rebecca; Momany, Michelle; Park, Chaeho; Straus, Anita Hilda [UNIFESP]; Takahashi, Helio Kiyoshi [UNIFESP]; Univ New Hampshire; Universidade Federal de São Paulo (UNIFESP); Univ Georgia
    Acidic glycosphingolipid components were extracted from the opportunistic mycopathogen Aspergillus fumigatus and identified as inositol phosphorylceramide and glycosylinositol phosphorylceramides (GIPCs). Using nuclear magnetic resonance sppectroscopy, mass spectrometry, and other techniques, the structures of six major components were elucidated as Ins-P-Cer (Af-0), Manp (alpha 1 -> 3) Manp(alpha 1 -> 2) Ins-P-Cer (Af-2), Manp(a1 -> 2) Manp (alpha 1 -> 3) Manp(alpha 1 -> 2) Ins-P-Cer (Af-3a), Manp(a1 -> 3) [Galf(beta 1 -> 6)] Manp(alpha 1 -> 2)-Ins-P-Cer (Af-3b), Manp (alpha 1 -> 2)-Manp(alpha 1 -> 3)[ Galf(beta 1 -> 6)] Manp(beta 1 -> 2) Ins-P-Cer (Af-4), and Manp(alpha 1 -> 3) Manp(alpha 1 -> 6) GlcpN(alpha 1 -> 2) Ins-P-Cer (Af-3c) ( where Ins 5 myo-inositol and P = phosphodiester). A minor A. fumigatus GIPC was also identified as the N-acetylated version of Af-3c (Af-3c*), which suggests that formation of the GlcN alpha 1 -> 2Ins linkage may proceed by a two-step process, similar to the GlcN alpha 1 -> 2Ins linkage in glycosylphosphatidylinositol (GPI) anchors (transfer of GlcNAc, followed by enzymatic de-N-acetylation). the glycosylinositol of Af-3b, which bears a distinctive branching Galf (b1Y6) residue, is identical to that of a GIPC isolated previously from the dimorphic mycopathogen Paracoccidioides brasiliensis (designated Pb-3), but components Af-3a and Af-4 have novel structures. Overlay immunostaining of A. fumigatus GIPCs separated on thinlayer chromatograms was used to assess their reactivity against sera from a patient with aspergillosis and against a murine monoclonal antibody (MEST-1) shown previously to react with the Galf (beta 1 -> 6) residue in Pb-3. These results are discussed in relation to pathogenicity and potential approaches to the immunodiagnosis of A. fumigatus.
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    Dimorphic expression of cerebrosides in the mycopathogen Sporothrix schenckii
    (Lipid Research Inc, 2000-05-01) Toledo, Marcos S. [UNIFESP]; Levery, Steven B.; Straus, Anita H. [UNIFESP]; Takahashi, Helio K. [UNIFESP]; Univ Georgia; Universidade Federal de São Paulo (UNIFESP)
    Major neutral glycosphingolipid components were extracted from Sporothrix schenckii, a dimorphic fungus exhibiting a hyphal saprophytic phase and a yeast parasitic phase responsible for chronic mycotic infections in mammalian hosts. These components, one from the mycelial form and two from the yeast form, were purified and their structures were elucidated by H-1 nuclear magnetic resonance (NMR) spectroscopy, electrospray ionization mass spectrometry (ESI-MS), and tandem ESI-MS/MS, All three were characterized as cerebrosides (monohexosylceramides) containing (4E, 8E)-9-methyl-4,8-sphingadienine as the long-chain base attached to N-2'-hydroxyoctadecanoate and N2'-hydroxy-(E)-Delta(3)-octadecenoate as the fatty acyl components. However, while the mycelial form expressed only beta-glucopyranosylceramide, the yeast form expressed both beta-gluco- and beta-galactopyranosylceramides in approximately equal amounts. In addition, while the glucosylceramides of both mycelial and yeast forms had similar proportions of saturated and (E)-Delta(3) unsaturated 2-hydroxy fatty acid, the galactocerebroside of the yeast form had significantly higher levels of (E)Delta(3) unsaturation. The differences in cerebroside hexose structure represent a novel type of glycosphingolipid dimorphism not previously reported in fungi, Possible implications of these findings with respect to regulation of morphological transitions in S, schenckii and other dimorphic fungi are discussed. Dimorphic expression of cerebrosides in the mycopathogen Sporothrix schenckii.