The in vitro cytopathic effect of Trichomonas vaginalis on epithelial cells was explored through the interaction of trophozoites of the virulent strain GT-10 with MDCK monolayers. The interaction was analyzed through electrophysiology, video microscopy, and transmission and scanning electron microscopy. Electrical measurements revealed that living parasites produced severe damage to the cell monolayers within 30 min, manifested as a rapid decrease in transepithelial resistance. Microscopic observations demonstrated that when placed in contact with epithelial cells, trichomonas formed clumps through interdigitations and transient plasma membrane junctions between adjacent parasites. Also, attached trophozoites adopted an ameboid shape. The in vitro cytopathic action of T. vaginalis on MDCK cells was initially evident by modifications of the plasma membrane, resulting in opening of tight junctions, membrane blebbing, and monolayer disruption. After 15 min of interaction the damage was focal, concentrating at sites where parasite clumps adhered to the monolayer. At 30 min practically all MDCK cells were dead, whether or not trichomonas were attached to them. These events were followed by detachment of lysed cells and complete disruption of the monolayer at 60 min. Electron microscopy demonstrated a peculiar form of adhesion that appears to be specific for trichomonas, in which the basal surface of T. vaginalis formed slender channels through which microvilli and cytoplasmic fragments of epithelial cells were internalized. The same sequence of lytic events was found with the less virulent GT-3 strain. However, the time course of cytolysis with GT-3 parasites was much slower, and lysis was limited to areas of attachment of T. vaginalis.

Abstract:In vitro studies to fourteen previously synthesized chromone-tetrazoles and four novel fluorine-containing analogs were conducted against pathogenic protozoan (Entamoeba histolytica), pathogenic bacteria (Pseudomonas aeruginosa, and Staphylococcus aureus), and human fungal pathogens (Sporothrix schenckii, Candida albicans, and Candida tropicalis), which have become in a serious health problem, mainly in tropical countries.

Antimicrobial peptides are widely distributed in nature; they play important roles in several aspects of innate immunity and may provide a basis for the design of novel therapeutic agents. In this study, C-amidated tritrpticin, a 13 amino acid tryptophan-rich antimicrobial peptide derived from a porcine cathelicidin, was tested against Trichomonas vaginalis, a protozoan that causes a serious non-viral sexually transmitted disease associated with preterm birth, low birth weight, and high risk of HIV-1 infection. Tritrpticin was selected due to its reasonably easy synthesis and because analogs with lower toxicity may be designed. Our results show that tritrpticin-NH(2) at either 100 or 200 μg/ml (52.5 or 105 μM) clearly reduces the viability and growth of Trichomonas vaginalis. Together with tritrpticin-NH(2), sodium bicarbonate further limited trichomonad growth. Additionally, a low concentration of metronidazole (5.8 μM), the most commonly used medication for Trichomonas vaginalis, was more effective against the growth of the parasite when it was combined with tritrpticin-NH(2).

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