Cell Surface Saccharides in Three Phytomonas Species Differing in Host Specificity

Abstract

ABSTRACT. Cell surface carbohydrates of three phytoflagellates, Phytomonas francai. Phytomonas serpens and Phytomonas sp. from different hosts including cassava, coreid insect Phthia picta and the milkweed plant Euphorbia hyssopifolia, respectively, were analysed by agglutination assays employing a battery of highly purified lectins with affinity for receptor molecules containing N‐acetylglucosamine (d‐GlcNAc), N‐acetylgalactosamine (D‐GalNAc), galactose, mannose‐like (D‐Man‐like) residues and fucose, and by binding assay using radiolabeled [125I]‐wheat germ agglutinin (WGA) and fluorescent WGA lectin, as well as glycosidases of known sugar specificity, Escherichia coli K with mannose‐affinity fimbrial lectin was also used as an agglutination probe. In general, the presence of D‐GlcNAc. D‐GalNAc and D‐Man‐like residues was detected in the phytomonads' plasma membrane. These sugar moieties were confirmed in whole cell hydrolysates as assessed by gas‐liquid chromatography (GLC) which in addition, also showed the presence of galactose and xylose. However, marked differences in cell surface carbohydrate structures were observed. Wheat germ agglutinin, which binds to sialic acid and/or d‐GlcNAc‐containing residues, shows selective agglutinin activities for P. francai and Phytomonas sp., while Bandeiraea simplicifolia II agglutinin (which recognizes d‐GlcNAc units) specifically bound to Phytomonas sp. Helix pomatia agglutinin which binds to D‐GalNAc‐containing residues reacted preferentially with Phytomonas sp. and P. serpens. Con A, which recognizes D‐Man‐like receptors, agglutinates all the phytomonads; however, the higher interaction was observed with Phytomonas sp. P. francai was selectively agglutinated in the presence of E. coli fimbrial lectin. Fluorescence WGA binding was significantly decreased by N‐acetylglucosaminidase activities and the cell agglutination was not altered by neuraminidase treatment, suggesting the presence of an exposed D‐GlcNAc moiety on the P. francai and Phytomonas sp. surfaces. Binding studies with [125I]‐WGA essentially confirmed the fluorescence WGA binding and agglutination assays.

Characterization of surface saccharides in twoCorynebacterium diphtheriaestrains

“…The number of WGA receptor sites ( n ) on C. diphtheriae corresponded to 2.8×10 5 per cell ( K o =4.0×10 6 M −1 ). These values fall within the range of the number of cell surface lectin receptor sites (10 5 –10 6 ) previously detected for other human pathogens [16].…”

“…Both sucrose‐negative (CDC‐E8392) and sucrose‐positive (number 241) strains were used in this study. Bacterial cells untreated and treated with neuraminidase of Clostridium perfringens (type X, Sigma) were analyzed by fluorescence assays employing wheat germ agglutinin from Triticum vulgaris (WGA) and Arachis hypogaea (PNA) lectins [16]. Bacterial suspension (20 μl) containing 2×10 7 bacterial cells per ml was placed on glass slides, air‐dried, and fixed in methanol for 10 min at 23°C.…”

Characterization of surface saccharides in two Corynebacterium diphtheriae strains

“…These values fall within the range of the number of cell surface lectin receptor sites (10 S^1 0 T ) previously detected for other human pathogens [16]. The presence of sialic acid moieties was con¢rmed in whole cell hydrolysates as assessed by TLC and GLC.…”

“…Both sucrosenegative (CDC-E8392) and sucrose-positive (number 241) strains were used in this study. Bacterial cells untreated and treated with neuraminidase of Clostridium perfringens (type X, Sigma) were analyzed by £uorescence assays employing wheat germ agglutinin from Triticum vulgaris (WGA) and Arachis hypogaea (PNA) lectins [16]. Bacterial suspension (20 Wl) containing 2U10…”

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

“…Sugar residues on the surface of cells, generally components of glycoproteins or glycolipids, are valuable markers for discriminating between distinct cell populations of similar morphology (Nakamura et al 1992). Additionally, cumulative evidence indicates that, in trypanosomatids, glycoconjugates are relevant in several phases of host-parasite interactions such as cellular recognition, adhesion, penetration, survival within host cells, and cell antigenicity (De Souza 1995;Colli and Alves 1999;Descoteaux and Turco 1999).…”