This Article Full Text (PDF) Other Versions of this Article: EC.00307-07v1 7/4/602    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Rodrigues, M. L. Articles by Casadevall, A. Search for Related Content PubMed PubMed Citation Articles by Rodrigues, M. L. Articles by Casadevall, A.

 Previous Article  |  Next Article 

Eukaryotic Cell doi:10.1128/EC.00307-07
Copyright (c) 2007, American Society for Microbiology and/or the Listed Authors/Institutions. All Rights Reserved.

Binding of the wheat germ lectin to Cryptococcus neoformans suggests an association of chitin-like structures with yeast budding and capsular glucuronoxylomannan

Laboratório de Estudos Integrados em Bioquímica Microbiana, Instituto de Microbiologia Professor Paulo de Góes, Universidade Federal do Rio de Janeiro, 21941-590, Brazil; Department of Microbiology and Immunology and Division of Infectious Diseases of the Department of Medicine, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, NY, 10461, USA

^* To whom correspondence should be addressed. Email: marcio{at}micro.ufrj.br. casadeva{at}aecom.yu.edu.

	Abstract

The capsule of Cryptococcus neoformans is a complex structure whose assembly requires intermolecular interactions to connect its components into an organized structure. In this study, we demonstrated that the wheat germ lectin (WGA), which binds to sialic acids and 1,4 N-acetylglucosamine (GlcNAc) oligomers, can also bind to cryptococcal capsular structures. Confocal microscopy demonstrated these structures form round or hook-like projections linking the capsule to the cell wall, as well as capsule-associated structures during yeast budding. Chemical analysis of capsular extracts by gas chromatography coupled to mass spectrometry and high pH-anion-exchange chromatography suggested that the molecules recognized by WGA were firmly associated to the cell wall. Enzymatic treatment, competition assays and staining with chemically modified WGA revealed that GlcNAc oligomers, but not sialic acids, were the molecules recognized by the lectin. Accordingly, treatment of C. neoformans cells with chitinase released glucuronoxylomannan (GXM) from the cell surface and reduced capsule size. Chitinase-treated acapsular cells bound soluble GXM in a modified pattern. These results indicate an association of chitin-derived structures with GXM and budding in C. neoformans, which may represent a new mechanism by which the capsular polysaccharide interacts with the cell wall and is rearranged during replication.

This article has been cited by other articles:

• Frases, S., Nimrichter, L., Viana, N. B., Nakouzi, A., Casadevall, A. (2008). Cryptococcus neoformans Capsular Polysaccharide and Exopolysaccharide Fractions Manifest Physical, Chemical, and Antigenic Differences. Eukaryot Cell 7: 319-327 [Abstract] [Full Text]