Here we report the effects of metronidazole and tinidazole on NTPDase1 and ecto-5P-nucleotidase from intact cells of Trichomonas vaginalis. Adenosine triphosphate (ATP) and adenosine diphosphate (ADP) hydrolysis was 5-to 7-fold higher for the fresh clinical strain, when compared with the ATCC (American Type Culture Collection) strain. ATP hydrolysis was activated in the presence of metronidazole in the ATCC strain, whilst it was inhibited 33% by 50 WM tinidazole in a fresh clinical isolate. The treatment of cells in the presence of metronidazole for 2 h inhibited ATP and ADP hydrolysis, whilst treatment with tinidazole inhibited ATP and ADP hydrolysis only in the fresh clinical isolate. The drugs did not change the ecto-5P-nucleotidase activity for both strains. Our results suggest that the modulation of extracellular ATP and ADP levels during treatment with these drugs could be a parasitic defence strategy as a survival mechanism in an adverse environment.
Monocercomonas sp. is a flagellate protozoan found in the large intestine of snakes and in insects. Light microscopy revealed the measurements of morphological features of the trophozoites. Scanning electron microscopy showed in detail the emergence of the three anterior flagella, the recurrent flagellum, the axostyle, and the absence of undulating membrane. In addition, we described spherical forms which are probably pseudocysts. The investigation on the occurrence of this process was carried out through the incubation of Monocercomonas sp. trophozoites in several stressful conditions, such as pH change, nutrient depletion and different temperatures. Results revealed high pseudocyst formation at acidic pH values (4.0, 5.0, and 6.0), in absence of serum and in incubation at 37 degrees C. The occurrence of these pseudocystic forms in trichomonads life cycle is under investigation. This study describes the external structure of Monocercomonas sp., as demonstrated by light and scanning electron microscopy. Moreover, to our knowledge, this is the first time that formation of probable pseudocysts is shown in Monocercomonas sp., contributing to the research field on termite protozoa biology.
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