Chemical organization of the cell wall polysaccharidic core of Malassezia restricta [Glycobiology and Extracellular Matrices]

March 13th, 2014 by Stalhberger, T., Simenel, C., Clavaud, C., Eiȷsink, V. G. H., Jourdain, R., Delepierre, M., Latge, J.–P., Breton, L., Fontaine, T.

Malassezia species are ubiquitous residents of human skin and are associated with several diseases, such as seborrheic dermatitis, tinea versicolor, folliculitis, atopic dermatitis, and scalp conditions such as dandruff. Host-Malassezia interactions and mechanisms to evade local immune responses remain largely unknown. M. restricta is one of the most predominant yeasts of the healthy human skin and in this paper, its cell wall has been investigated. Polysaccharides in the M. restricta cell wall are almost exclusively alkali-insoluble, showing that they play an essential role in the organization and rigidity of the M. restricta cell wall. Fractionation of cell wall polymers and carbohydrate analyses showed that the polysaccharidic core of the cell wall of M. restricta contained an average of 5% chitin, 20% chitosan, 5% β-(1,3)-glucan and 70% β-(1,6)-glucan. In contrast to other yeasts, chitin and chitosan are relatively abundant and β-(1,3)-glucans constitute a minor cell wall component. The most abundant polymer is β-(1,6)-glucans that are large molecules composed of a linear β-(1,6)-glucan chains with β-(1,3)-glucosyl side chain with an average of 1 branch point every 3.8 glucose unit. Both β-glucans are cross-linked, forming a huge alkali-insoluble complex with chitin and chitosan polymers. Data presented here shows that M. restricta has a polysaccharide organization very different of all fungal species analysed to date.