Differential lectin recognition of glycoproteins in choanomastigote-shaped trypanosomatids: taxonomic implications

Abstract

The glycoprotein profiles of seven choanomastigote-shaped trypanosomatids (six Crithidia spp. and one Herpetomonas sp.), which have been suggested to form three distinct taxonomic groups (Crithidia, Angomonas and Strigomonas), were analyzed by Western blotting using the lectins Limax flavus (LFA), Sambucus nigra (SNA) and Maackia amurensis (MAA), which specifically recognize sialic acid residues, and concanavalin A (Con A) that recognizes mannose-like residues in glycoconjugates. All lectins showed a sugar-inhibited recognition with the parasite extracts, with the exception of LFA, which did not show any reactivity with the studied species. The SNA agglutinin presented a characteristic and specific pattern for each taxonomic group. The MAA lectin showed an identical profile for all species analyzed, while Con A grouped the choanomastigote-shaped species in two different patterns, one specific for the Angomonas group, and the other comprehending both Strigomonas and Crithidia groups. These results illustrate the heterogeneity of the genus Crithidia. The possible taxonomic redistribution of the choanomastigote-shaped trypanosomatids is also discussed.

Influence of the endosymbiont ofBlastocrithidia culicisandCrithidia deaneion the glycoconjugate expression and onAedes aegyptiinteraction

“…Conversely, symbiont-containing cells have 3-4-fold higher agglutination titers with a fucosebinding agglutinin than symbiont-free organisms [8]. The different carbohydrate composition detected between C. deanei and C. oncopelti may be attributed to group-specific sugars, as previously reported by our research group [25]. For instance, no agglutination was detected with the fucose-binding lectins Lotus tetragonolobus and Ulex europeus.…”

“…Valuable information on the structure and function of cell surface saccharides is derived from studies with lectins, a class of sugar-binding proteins of non-immune origin. This has already been observed in the Crithidia [21,25], Herpetomonas [22] and Phytomonas [23] genera. Sialic acids (SA) are a family of carboxylated ninecarbon sugars found in glycoproteins and glycolipids at the nonreducing end of oligosaccharides, linked to galactose and N-acetyl-D-galactosamine [19].…”

“…Among the many techniques employing lectins in order to evaluate the presence of sialic acids on the surface of trypanosomatids reviewed in [15], the utilization of Western blotting analysis to identify sialoglycoconjugates in total cellular extracts has been performed only recently in these microorganisms [22,23,25]. Valuable information on the structure and function of cell surface saccharides is derived from studies with lectins, a class of sugar-binding proteins of non-immune origin.…”

“…The membranes were incubated with the following peroxidase-labeled lectins: LFA at 1:100 dilution, SNA at a 1:400 dilution, MAA at 1:500 dilution and Con A at a final concentration of 25 lg/ml in blocking solution for 1 h. The specificity of the binding was checked by the incubation of the membrane strips in the presence of each lectin (LFA, SNA, MAA and Con A) and its specific sugar inhibitor(s) [25]. The membranes were incubated with the following peroxidase-labeled lectins: LFA at 1:100 dilution, SNA at a 1:400 dilution, MAA at 1:500 dilution and Con A at a final concentration of 25 lg/ml in blocking solution for 1 h. The specificity of the binding was checked by the incubation of the membrane strips in the presence of each lectin (LFA, SNA, MAA and Con A) and its specific sugar inhibitor(s) [25].…”

Lectinomics I. Relevance of exogenous plant lectins in biomedical diagnostics

“…were analyzed by Western blotting using the lectins LFA, SNA, and MAA, which specifically recognize sialic acid residues, and Con A, which recognizes mannose residues. The results obtained illustrated the heterogeneity of the genus Crithidia (d'Avila- Levy et al 2004).…”