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

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, Brazil. 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.Peer reviewedPublisher PD

The structure of a complex glycosylphosphatidyl inositol-anchored glucoxylan from the kinetoplastid protozoan Leptomonas samueli.

The structure of a glycosylphosphatidyl inositol-anchored glucoxylan (GPI-glucoxylan) synthesized by the monogenetic trypanosomatid Leptomonas samueli has been determined. The glucoxylan is anchored to the membrane by phytoceramide and an oligosaccharide core, the structure of which is identical to glycoinositolphospholipids (GIPLs) expressed by this protozoan. The glucoxylan chain is linear, containing -->4Glcalpha1-->, -->4Xylbeta1--> and -->3Xylbeta1--> residues. A well defined sequence heterogeneity was analysed in terms of a series of overlapping trisaccharide substructures. A proportion of the chains are capped with a GlcAalpha1-->3Glcalpha1--> sequence. While an average GlcA-capped chain contained 10 Glc and 16 Xyl residues, uncapped chains have a higher molecular mass with an average of 30 Glc and 50 Xyl per chain. We propose a mode of biosynthesis based on the observed structural heterogeneity

α-N-acetylglucosamine-linked O-glycans of sialoglycoproteins (Tc-mucins) from Trypanosoma cruzi Colombiana strain

Trypanosoma cruzi sialoglycoproteins (Tc-mucins) are mucin-like molecules linked to a parasite membrane via a glycosylphosphatidylinositol anchor. We previously determined the structures of Tc-mucin O-glycan domains from several T. cruzi strains and observed significant differences among them. We now report the amino acid content and structure of Tc-mucin O-glycan chains from T. cruzi Colombiana, a strain resistant to common trypanocidal drugs. Amino acid analysis demonstrated the predominance of threonine residues (42%) and helped to identify the O-glycans as belonging to a Tc-mucin family that contain a ²-galactofuranose (²-Galf) residue attached to an α-N-acetylglucosamine (α-GlcNAc) O-4, with the most complex glycan, a pentasaccharide-GlcNAc-ol with a branched trigalactopyranose chain, on the GlcNAc O-6. The presence of ²-Galf on O-glycans from T. cruzi Colombiana mucins supports the use of glycosylation as a phylogenetic marker for the classification of Colombiana in the T. cruzi I group