Differential expression of sialylglycoconjugates and sialidase activity in distinct morphological stages of Fonsecaea pedrosoi

Differential expression of sialylglycoconjugates and sialidase activity in distinct morphological stages of Fonsecaea pedrosoi

Author Alviano, D. S. Google Scholar
Rodrigues, M. L. Google Scholar
Almeida, C. A. Google Scholar
Santos, ALS Google Scholar
Couceiro, JNSS Google Scholar
Soares, RMA Google Scholar
Travassos, L. R. Google Scholar
Alviano, C. S. Google Scholar
Institution Universidade Federal do Rio de Janeiro (UFRJ)
Universidade Federal de São Paulo (UNIFESP)
Abstract The expression of sialoglycoconjugates in Fonsecaea pedrosoi conidia, mycelia, and sclerotic cells was analyzed using influenza A and C virus strains, sialidase treatment, and lectin binding. Conidium and mycelium whole cells were recognized by Limax flavus (LFA), Maackia amurensis (MAA), and Sambucus nigra (SNA) lectins, denoting the presence of surface sialoglycoconjugates containing alpha2,3- and alpha2,6-sialylgalactosyl sequences. Sialidase-treated conidia reacted more intensively with peanut agglutinin (PNA), confirming the occurrence of sialyl-galactosyl linkages. Conidial cells agglutinated in the presence of influenza A and C virus strains, which confirmed the results obtained from lectin-binding experiments and revealed the presence of sialoglycoconjugates bearing 9-O-acetyl-N-acetylneuraminic acid (Neu5,9Ac(2)) surface structures. Western blotting analysis with peroxidase-labeled LFA demonstrated the occurrence of sialylglycoproteins in protein extracts from conidia and mycelia, with molecular masses corresponding to 56 and 40 kDa. An additional band of 77 kDa was detected in conidial extracts, suggesting an association between sialic acid expression and morphogenesis. Synthesis of sialic acids was correlated with sialidase expression, since both conidial and mycelial morphological stages presented secreted and cell-associated enzyme activity. Sialoglycoconjugates were not detected in F. pedrosoi sclerotic cells from in vitro and in vivo sources, which also do not express sialidase activity. the surface sialyl residues in F. pedrosoi are apparently involved in the fungal interaction with immune effector cells, since sialidase-treated conidia were less resistant to phagocytosis by human neutrophils from healthy individuals. These findings suggest that sialic acid expression in F. pedrosoi varies according to the morphological transition and may protect infecting propagules against immune destruction by host cells.
Keywords Fonsecaea pedrosoi
sialic acid
Language English
Date 2004-04-01
Published in Archives of Microbiology. New York: Springer-verlag, v. 181, n. 4, p. 278-286, 2004.
ISSN 0302-8933 (Sherpa/Romeo, impact factor)
Publisher Springer
Extent 278-286
Origin http://dx.doi.org/10.1007/s00203-004-0653-9
Access rights Closed access
Type Article
Web of Science ID WOS:000220385200003
URI http://repositorio.unifesp.br/handle/11600/27690

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