Eukaryotic Cell
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Other Versions of this Article:
EC.00306-06v1
6/1/95    most recent
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Maxson, M. E.
Right arrow Articles by Zaragoza, O.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Maxson, M. E.
Right arrow Articles by Zaragoza, O.

 Previous Article  |  Next Article 

Eukaryotic Cell, January 2007, p. 95-109, Vol. 6, No. 1
1535-9778/07/$08.00+0     doi:10.1128/EC.00306-06
Copyright © 2007, American Society for Microbiology. All Rights Reserved.

Radial Mass Density, Charge, and Epitope Distribution in the Cryptococcus neoformans Capsule{triangledown}

Michelle E. Maxson,1 Ekaterina Dadachova,1,2 Arturo Casadevall,1,3,{dagger}* and Oscar Zaragoza1,{dagger}*

Departments of Microbiology and Immunology,1 Medicine,3 Nuclear Medicine, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 104612

Received 26 September 2006/ Accepted 10 November 2006

Exposure of Cryptococcus neoformans cells to gamma radiation results in a gradual release of capsular polysaccharide, in a dose-dependent manner. This method allows the systematic exploration of different capsular regions. Using this methodology, capsule density was determined to change according to the radial distribution of glucuronoxylomannan and total polysaccharide, becoming denser at the inner regions of the capsule. Scanning electron microscopy of cells following gamma radiation treatment confirmed this finding. The zeta potential of the capsule also increased as the capsule size decreased. However, neither charge nor density differences were correlated with any change in sugar composition (xylose, mannose, and glucuronic acid) in the different capsular regions, since the proportions of these sugars remained constant throughout the capsule. Analysis of the capsular antigenic properties by monoclonal antibody binding and Scatchard analysis revealed fluctuations in the binding affinity within the capsule but not in the number of antibody binding sites, suggesting that the spatial organization of high- and low-affinity epitopes within the capsule changed according to radial position. Finally, evidence is presented that the structure of the capsule changes with capsule age, since the capsule of older cells became more resistant to gamma radiation-induced ablation. In summary, the capsule of C. neoformans is heterogeneous in its spatial distribution and changes with age. Furthermore, our results suggest several mechanisms by which the capsule may protect the fungal cell against exogenous environmental factors.

* Corresponding author. Present address for Oscar Zaragoza: Servicio de Micología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Ctra. Majadahonda-Pozuelo Km 2, Majadahonda, Madrid 28220, Spain. Phone: 34918223661. Fax: 34915097034. E-mail: ozaragoza{at}isciii.es. Mailing address for Arturo Casadevall: Departments of Microbiology and Immunology and Medicine, Albert Einstein College of Medicine, 1300 Morris Part Avenue, Bronx, New York 10461. Phone: (718) 430-3665. Fax: (718) 430-8701. E-mail: casadeva{at}aecom.yu.edu.

{triangledown} Published ahead of print on 17 November 2006.

{dagger} Arturo Casadevall and Oscar Zaragoza share senior authorship of this paper.

Eukaryotic Cell, January 2007, p. 95-109, Vol. 6, No. 1
1535-9778/07/$08.00+0     doi:10.1128/EC.00306-06
Copyright © 2007, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:



HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Appl. Environ. Microbiol. Infect. Immun. J. Bacteriol.
Mol. Cell Biol. Microbiol. Mol. Biol. Rev. ALL ASM JOURNALS
Copyright © 2007 by the American Society for Microbiology.