Identification of sialic acids on the cell surface of hyphae and yeast forms of the human pathogen Paracoccidioides brasiliensis.
Paracoccidioides brasiliensis, the agent of paracoccidioidomycosis, when grown in a synthetic medium, expresses at the cell surface of both yeast and mycelial forms acidic glycoconjugates containing N-acetylneuraminic acid units. Sialic acids were extracted using mild hydrolytic conditions, and were identified by thin-layer and gas chromatography, standard colorimetry, reaction with periodate-resorcinol and mass spectrometry. Their surface location was inferred from fluorescent-lectin (Limulus polyphemus agglutinin) binding to whole cells abrogated by previous treatment with neuraminidase. Expression of sialic acids on virulent yeast forms of P. brasiliensis (3.7 x 10(6) residues per cell) may inhibit fungal phagocytosis during early infection, when the immunological response is still being built up.
Soares
R M
RM
Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
Alviano
C S
CS
Angluster
J
J
Travassos
L R
LR
D002462:Cell Membrane / Q000378:metabolism; D003124:Colorimetry; D006801:Humans; D037102:Lectins / Q000378:metabolism; D010228:Paracoccidioides / Q000254:growth & development / Q000378:metabolism* / Q000472:pathogenicity; D010229:Paracoccidioidomycosis / Q000209:etiology; D012794:Sialic Acids / Q000032:analysis / Q000378:metabolism*; D014774:Virulence
D037102:Lectins; D012794:Sialic Acids