Evaluation of the susceptibility of Tritrichomonas foetus to extracts of Lantana camara (Verbenaceae) by flow cytometry.

Bovine Trichomonosis (BT), a sexually transmitted disease endemic in countries with extensive cattle farming and natural service, is one of the most common causes of reproductive failure. 5-nitroimidazoles and their derivatives are used for its treatment, mainly metronidazole. The emergence of drug resistance mechanisms and treatment failures raise the need to investigate the effectiveness of new active compounds that contribute to parasite control. In this regard, extracts of Lantana camara (Verbenacea) have shown high biocidal potential against isolates of Trypanosoma cruzi and Leishmania braziliensis in vitro assays, although their effect on Tritrichomonas foetus has not been demonstrated yet. The available information on in vitro susceptibility of trichomonicidal drugs comes from the use of a diversity of methodologies and criteria, especially the observation of parasite motility under the optical microscope to assess their viability. Recently, in our laboratory, the use of flow cytometry has been described for the first time as a rapid and efficient method to evaluate the viability of T. foetus against metronidazole. The present study aimed to evaluate the cytostatic effect of L. camara extracts against T. foetus isolates by flow cytometry. Under aerobic conditions, IC50 values of 22.60 µg/mL were obtained on average. Under anaerobic conditions, the IC50 oscilated around 29.04 µg/mL. The results obtained allowed describing the susceptibility exhibited by these protozoa, being a valuable information for the development of potential BT treatments.

Cell adhesion glycoprotein vitronectin during Xenopus laevis embryogenesis.

Vitronectin (vn) is a cell-adhesive glycoprotein present in blood and extracellular matrix of all vertebrates. In the present study we reported the cDNA cloning of Xenopus laevisvitronectin and its spatial and temporal expression pattern during the embryonic development of this important model organism. The deduced amino acid sequence of Xenopus laevis vn showed 49%, 47% and 43% identity with human, chicken and zebrafish orthologs, respectively, whereas the comparison with Xenopus tropicalis vn presented 85% identity. The structural organization consisting of a somatomedin B domain and two hemopexin-like domains was similar to higher vertebrate vitronectins. The vn transcripts were detected from stage 28 onward. At tadpole stages, vn is expressed in heart, gut derivatives and in the notochord. The protein was detected in heart, liver, foregut, pronephros and notochord at stages 43 and 47 of Xenopus embryos. Our results suggest that vitronectin is developmentally regulated and could participate in embryo organogenesis.