Vera L. Bonilha

The involvement of terminal carbohydrates of the mammalian cell surface in the cytoadhesion of trichomonads.

In the present study the parental cells and glycosylation mutants of Chinese hamster ovary (CHO) cells were used to analyze the influence of surface carbohydrates on the cytoadhesion of trichomonads.Trichomonas vaginalis andTritrichomonas foetus were allowed to interact with host cells for 2 h at 37°C. Alternatively, CHO cells were treated with 10 mM periodate prior to the assays. Both trichomonads adhered to all CHO cell clones tested. A remarkable difference could be observed between the cytoadhesion ofT. vaginalis andT. foetus. Sialic acid residues present on the surface of CHO cells may favor the cytoadhesion ofT. foetus while hampering that ofT. vaginalis. The specificity of the parasite cytoadhesion was further investigated. Sialic acid, mannose, and galactose as well as mannose, galactose, andN-acetylglucosamine added to the interaction medium at 50, 100, and 200 mM were capable of significantly inhibiting the cytoadhesion of each trichomonad species. Periodate treatment of target cells also induced decreases in the cytoadhesion of the trichomonads. These results strongly sugest an important role for host-cell surface glycoconjugates during the cytoadhesion of trichomonads. In addition, they also point out the presence of “lectin-like” molecules on the surface of bothT. vaginalis andT. foetus.

Effect of a phorbol ester on basic surface properties of trichomonads

The effect of nanomolar concentrations of 12-O-tetradecanoil-phorbol-13-acetate (TPA) on the cell surface of the urogenital parasitic protozoaTrichomonas vaginalis andTritrichomonas foetus was evaluated by means of measurements of the parasites’ surface tension, electrokinesis, lectin agglutination tests, and adhesion to inert substrates. TPA-treated parasites had their adhesion increased to both plastic and glass substrates. This was accompanied by increases in the parasites’ net negative surface charge and also by changes in their surface tension. The lectin agglutination assays suggest that the increase in surface negativeness may be related in some extent to alterations in the oligosaccharide composition. Successive treatment of the microorganisms with TPA and sphingosine, a well-known competitive inhibitor of the phorbol ester active site, depressed the tendency of trichomonads to exhibit a phenotype of activated cells.

Correction: DJ-1-Dependent Regulation of Oxidative Stress in the Retinal Pigment Epithelium (RPE)

[This corrects the article DOI: 10.1371/journal.pone.0067983.].