TRICHOMONAS-VAGINALIS AND TRITRICHOMONAS-FETUS - EXPRESSION OF CHITINAT THE CELL-SURFACE

The expression of chitin as a structural component of Trichomonas vagi nalis and Tritrichomonas foetus was demonstrated by using enzymatic hy drolysis by recombinant (rec-) chitinase, chemical analysis, lectin, f luorescent Calcofluor and antibody binding, glycosidases of known spec ificity high-performance liquid chromatography (HPLC), and flow cytome try. Chitinous structures were characterized by their insolubility in hot alkali and by releasing glucosamine on hydrolysis with 6 N HCl. N, N'-Diacetylchitobiose and N,N,'N ''-triacetylchitotriose were identifi ed by HPLC as enzymatic hydrolysis products of the alkali-resistant po lysaccharide. The location of chitin on the surface of I: vaginalis an d T. foetus was inferred from the decreased reactivity with whole para sites of ligands such as Lycopersicon esculentum (TOL) and Solanum tub erosum lectins, fluorescent Calcofluor, and anti-chitin antibody, afte r cell treatment with rec-chitinase. Binding of [I-125]TOL showed that , in T. vaginalis and T. foetus, the numbers of lectin receptors per c ell were 4.2 x 10(5) and 3.0 x 10(5), respectively. Binding of the lec tin to the trichomonad surface was markedly decreased by treatment wit h rec-chitinase. TOL interaction with the parasites was not affected b y N-acetyl-beta-D-glucosaminidase treatment, showing that the lectin r eceptors consisted of beta-linked GlcNAc polymers and not of terminal beta-linked GlcNAc residues. (C) 1998 Academic Press.