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Automated Measurement of Cryptococcal Species Polysaccharide Capsule and Cell Body
Published on: January 11, 2018
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Cryptococcus neoformans capsular polysaccharides form branched and complex filamentous networks viewed by
Glauber R de S Araújo1, Giselle N Fontes2, Daniela Leão2
1Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; National Institute of Metrology, Quality and Technology (Inmetro), Duque de Caxias, Rio de Janeiro, Brazil.
Journal of Structural Biology
|December 15, 2015
Summary
The Cryptococcus neoformans capsule, a key virulence factor, has a complex, branched polysaccharide structure, unlike typical linear polymers. This microgel-like conformation may explain its role in fungal infections.
Area of Science:
- Mycology
- Microbiology
- Biochemistry
Background:
- Cryptococcus neoformans is an opportunistic fungal pathogen causing severe infections in immunocompromised individuals.
- The fungal capsule is a major virulence factor, but its structure, assembly, and dynamics are not well understood.
Purpose of the Study:
- To visualize the ultrastructure of the C. neoformans capsule at high resolution.
- To elucidate the structural basis of the capsule's role as a virulence factor.
Main Methods:
- Utilized improved sample preparation protocols.
- Employed advanced scanning microscopy techniques for high-resolution imaging (up to 1 nm).
- Achieved improved structural preservation of the fungal capsule.
Main Results:
- Revealed the C. neoformans capsule is a 'microgel-like' structure composed of branched polysaccharides.
- Demonstrated that capsule structures are not linear polymers.
- Imaged the capsule-to-cell wall link, showing thin fibers branching from thicker filaments embedded in the cell wall.
Conclusions:
- The C. neoformans capsule possesses a complex, branched ultrastructure.
- This unique conformation has significant implications for the capsule's biological activity and virulence.
- Provides compelling evidence for a non-linear polysaccharide architecture in the fungal capsule.
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