Fernanda Pires Borges

Scanning electron microscopy study of Tritrichomonas augusta

Abstract Tritrichomonas augusta is a flagellated protozoan that parasitizes amphibians and reptiles. According to scanning electron microscopy (SEM), the cell shape of T. augusta varies from slender pyriform to ovoidal. Our data show the morphological features of the trophozoites: the emergence of the anterior flagella, the structure of the undulating membrane and the position and shape of the pelta, axostyle and posterior flagellum. In addition, herein we describe spherical forms which are probably pseudocysts. The description of the external structure of T. augusta, as demonstrated by SEM, contributes to the understanding of the biology of this parasite.

Trichomonas vaginalis: Dehydroepiandrosterone sulfate and 17β-estradiol alter NTPDase activity and gene expression

We investigated the effect of dehydroepiandrosterone sulfate (DHEAS) and 17beta-estradiol on NTPDase activity in fresh clinical (VP60) and long-term-grown (30236 ATCC) isolates of Trichomonas vaginalis followed by NTPDase gene transcriptional analysis. ATP hydrolysis was activated in vitro by 17beta-estradiol (0.01-1.0microM) in the VP60 isolate. Treatment for 2h with 17beta-estradiol (0.01-1microM) promoted an inhibition in nucleotide hydrolysis in the 30236 isolate whereas the 12h-treatment promoted an activation of nucleotide hydrolysis in both isolates. ADP hydrolysis was inhibited in vitro by 1.0-5.0microM DHEAS in the ATCC isolate. The treatment with DHEAS (0.01-1.0microM) for 2h inhibited ATP and ADP hydrolysis in VP60; however, during a 12h-treatment with DHEAS, nucleotide hydrolysis was inhibited in both isolates. Two NTPDase orthologous (NTPDaseA and NTPDaseB) were identified and the treatment with DHEAS for 12h was able to inhibit mRNA NTPDaseA transcript levels from the VP60. These findings demonstrate that NTPDase activity and gene expression pattern are modulated by exposure to steroids in T. vaginalis.

Morphological aspects of Monocercomonas sp. and investigation on probable pseudocysts occurrence.

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°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.

Analysis of microtubule cytoskeleton distribution using a fluorescent taxoid in two trichomonadid protozoa : Trichomonas gallinae and Tritrichomonas foetus

Trichomonas gallinae and Tritrichomonas foetus are flagellated parasitic protozoa of the upper digestive tract of birds and the urogenital tract of cattle, respectively. Both of these species are important in the veterinary field, due to the fact that they cause significant economic losses. Therefore, we investigated the morphology of these parasites by studying microtubule cytoskeleton organization. FLUTAX-2, an active fluorescent derivative of Taxol, was used in this study. This fluorescent taxoid binds to polymerized alphabeta-tubulin dimers. Our results showed that FLUTAX-2 was able to bind to and stabilize microtubules of intact T. gallinae and T. foetus trophozoites, allowing the microtubular cytoskeleton to be easily observed by fluorescence microscopy. T. foetus and T. gallinae had no differences in their FLUTAX-2 binding profiles. Further studies may allow this technique to be improved, and it may possibly be used as a routine laboratory method for the diagnosis of avian and bovine trichomonosis.

A meninice mentida e o futuro profanado: as narrativas de Valêncio Xavier

The works of Valencio Xavier are characterized, in formal terms, by using various types of images (drawings, photographs, newspaper articles, flip books), elements that make hybrid narratives. Such artifacts are arranged in order to compose an album in the novel Minha mae morrendo e o menino mentido and an obituary in Meu 7o dia: uma novella rebus. From a lied childhood to a desecrated funeral, Valencio Xavier lights and reworks childhood memories and designs and mocks the inevitable future. Thus, this study aims to discuss structural and thematic attributes of the works of this Brazilian author to reflect on these narrative albums that create the past and the future.