Changes of sialomolecules during the dimethylsulfoxide-induced differentiation of Herpetomonas samuelpessoai

Abstract

The expression of sialoglycoconjugates during the dimethylsulfoxide (DMSO)-induced differentiation of Herpetomonas samuelpessoai was analyzed by flow cytometry and Western blotting using sialic acid-specific lectins. Parasites reacted strongly with Limax flavus (LFA) and Sambucus nigra (SNA) agglutinins, and only weakly with Maackia amurensis (MAA) lectin. However, analysis of crude protein extracts by Western blotting revealed that bands with molecular masses corresponding to 15 and 40 kDa are recognized by MAA, and that treatment with DMSO induced the expression of two additional polypeptides with molecular masses of 65 and 90 kDa. Profiles of binding to LFA were indistinguishable when protein extracts from control or differentiated cells were analyzed. SNA recognized a major molecule with 25 kDa in extracts from non-differentiated forms and two low-molecular-weight bands from differentiated cells. These results indicate that molecules containing alpha2,6 and alpha2,3 sialyl-galactosyl sequences are present in H. samuelpessoai, and that their biosynthesis and expression are influenced by DMSO-induced differentiation.

Biological Roles of Peptidases in Trypanosomatids~!2009-11-26~!2010-02-15~!2010-03-18~!

“…The lack of equal expression may be correlated to the parasites growth and/or cell cycle phases, since flagellate cultures were not synchronized. Furthermore, the occurrence of distinct subpopulations could alternatively denote a different expression of surface gp63-like molecules in the different developmental stages or even a diminished accessibility to external ligands in cell subsets, as previously reported for other trypanosomatid cell surface molecules [12,27]. Conversely, the extracellular isoform can be released from parasite cells by two mechanisms that follow the classic secretory pathway with routing of gp63 from the endoplasmic reticulum to the Golgi network and then into the flagellar pocket.…”

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

“…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.…”

“…At least 50,000 cells were analyzed per sample with four repeats per experiment [21,22]. After incubation, the parasite-associated fluorescence was excited at 488 nm and quantified on a fluorescence-activated cell sorter (FACS) FACSCalibur (BD Bioscience, USA).…”

Effect of sphingosine and phorbol-12-myristate-13-acetate on the growth and dimethylsulfoxide-induced differentiation in the insect trypanosomatid Herpetomonas samuelpessoai

“…Several Brazilian researchers have used this parasite as a very interesting model to study cellular differentiation, since H. samuelpessoai possesses three distinct morphological stages (promastigote, paramastigote, and opisthomastigote) during its life cycle either in culture or in the invertebrate vector (Angluster et al 1977, Castellanos et al 1980, Souza et al. 1980, Thomas et al 1981a,b, Santos et al 2001, 2002a,b, 2003a.In protozoa as in higher eukaryotes, cellular differentiation occurs as result of selective gene expression, which is controlled in various ways. Differentiation is often initiated in response to external stimuli such as the binding of ligands to the cell surface (Parsons & Ruben 2000).…”

“…The H. samuelpessoai differentiation mechanism is triggered by chemical and physical changes in the growth conditions. Previous studies have shown that the binding and/or interaction to the plasma membrane of drugs such as 2-deoxy-D-glucose (Angluster et al 1977), Concanavalin A (Souza et al 1980, cholinergic drugs (Thomas et al 1981a), local anesthetic (Thomas et al 1981b, and dimethylsulfoxide (DMSO) (Castellanos et al 1980) induce the differentiation process in H. samuelpessoai, which is associated with several changes in the parasite biochemical machinery (Santos et al 2001(Santos et al , 2002a(Santos et al ,b, 2003a. Nevertheless, very little is known about the signal transduction pathways involved in the differentiation process of this monoxenous flagellate.…”