Cell walls of the dimorphic fungal pathogens Sporothrix schenckii and Sporothrix brasiliensis exhibit bilaminate structures and sloughing of extensive and intact layers

Leila M Lopes Bezerra* (Corresponding Author), Louise A Walker, Gustavo Niño Vega, Héctor M. MoraMontes, Gabriela W P Neves, Hector Villalobos-Duno, Laura Barreto, Karina Garcia, Bernardo Franco, José A. Martínez-Álvarez, Carol A Munro, Neil A R Gow

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

51 Citations (Scopus)
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Sporotrichosis is a subcutaneous mycosis caused by pathogenic species of the Sporothrix genus. A new emerging species, Sporothrix brasiliensis, is related to cat-transmitted sporotrichosis and has severe clinical manifestations. The cell wall of pathogenic fungi is a unique structure and impacts directly on the host immune response. We reveal and compare the cell wall structures of Sporothrix schenckii and S. brasiliensis using high-pressure freezing electron microscopy to study the cell wall organization of both species. To analyze the components of the cell wall, we also used infrared and 13C and 1H NMR spectroscopy and the sugar composition was determined by quantitative high-performance anion-exchange chromatography. Our ultrastructural data revealed a bi-layered cell wall structure for both species, including an external microfibrillar layer and an inner electron-dense layer. The inner and outer layers of the S. brasiliensis cell wall were thicker than those of S. schenckii s. str., correlating with an increase in the chitin and rhamnose contents. Moreover, the outer microfibrillar layer of the S. brasiliensis cell wall had longer microfibrils interconnecting yeast cells. Distinct from those of other dimorphic fungi, the cell wall of Sporothrix spp. lacked α-glucan component. Interestingly, glycogen α-particles were identified in the cytoplasm close to the cell wall and the plasma membrane. The cell wall structure as well as the presence of glycogen α-particles varied over time during cell culture. The structural differences observed in the cell wall of these Sporothrix species seemed to impact its uptake by monocyte-derived human macrophages. The data presented here show a unique cell wall structure of S. brasiliensis and S. schenckii during the yeast parasitic phase. A new cell wall model for Sporothrix spp. is therefore proposed that suggests that these fungi molt sheets of intact cell wall layers. This observation may have significant effects on localized and disseminated immunopathology.
Original languageEnglish
Article numbere0006169
JournalPLoS Neglected Tropical Diseases
Issue number3
Publication statusPublished - 9 Mar 2018

Bibliographical note

This work was supported by the Fundação Carlos Chagas de Amparo à Pesquisa do
Estado do Rio de Janeiro (FAPERJ), grants E-26/202.974/2015 and Conselho
Nacional de Desenvolvimento Científico e Tecnológico (CNPq), grants 229755/2013-5,
LMLB is a senior research fellow of CNPq and Faperj. NG acknowledged support from
the Wellcome Trust (Trust (097377, 101873, 200208) and MRC Centre for Medical
Mycology (MR/N006364/1).
The funders had no role in study design, data collection and analysis, decision to
publish, or preparation of the manuscript.


  • cell wall
  • dimorphic fungi
  • Sporothrix brasiliensis
  • Sporothrix schenckii
  • peptidorhamnomannan
  • beta-glucan
  • chitin
  • glycogen alpha particle
  • human macrophage
  • cell surface


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