Cell death in trichomonads: new insights.

Tritrichomonas foetus is an amitochondriate parasite that possesses hydrogenosomes, unusual anerobic energy-producing organelles. In these organisms the "mitochondrial cell death machinery" is supposed to be absent, and the mechanisms that lead to cell demise remain to be elucidated. The presence of a cell death program in trichomonads has already been reported, suggesting the existence of a caspase-like execution pathway in such organisms. Here we demonstrate the alterations provoked by the fungicide griseofulvin and raise the possibility that other cell death pathways may exist in T. foetus. Dramatic changes in trichomonads morphology are presented after griseofulvin treatment, such as intense plasma membrane and nuclear envelope blebbing, nucleus fragmentation, and an abnormal number of oversized vacuoles. One important finding was the exposition of phosphatidylserine (PS) in the outer leaflet of the plasma membrane in cells after drug treatment, and also the presence of a high amount of misshapen flagella and tubulin precipitates as vacuolar contents, suggesting an autophagic process of abnormal cellular elements. Interestingly, immunoreactivity for activated caspase-3 was not detected during griseofulvin treatment, a finding distinct from the observed when this cell was treated with H(2)O(2). The possibility of the existence of different pathways to cell death in trichomonads is discussed.

Special organelles of some pathogenic protozoa.

Parasitic protozoa comprise a large number of species, some of which are agents of important diseases. They are also of interest from the point of view of cell biology since they contain special organelles and structures. This review analyses our present knowledge of (1). the glycosomes, found in members of the Kinetoplastida order, (2). the hydrogenosomes found in some anaerobic protozoa, especially in trichomonads, (3). the acidocalcisomes, recently described in several protozoa, and (4). structures and organelles participating in the endocytic pathway in trypanosomatids.

Tritrichomonas foetus: induced division synchrony by hydroxyurea.

Treatment of cultures of Tritrichomonas foetus with 4 mM hydroxyurea (HU), a known DNA synthesis inhibitor, induced pseudocyst formation and caused a mitotic burst. An hour after drug release there was a characteristic, synchronous burst of cell division. T. foetus culture was arrested in the G2/M phase. The synchrony index varied from 66% to 69%. The synchrony was maintained for several cell cycles, even in thawed cultures which had been frozen for storage in liquid nitrogen. The synchronized cells were analyzed by light and scanning electron microscopy, as well by flow cytometry.

Morphologic aspects of Tetratrichomonas didelphidis isolated from opossums Didelphis marsupialis and Lutreolina crassicaudata.

Tetratrichomonas didelphidis (Hegner & Ratcliffe, 1927) Andersen & Reilly, 1965 is a flagellate protozoan found in the intestine, cecum, and colon of Didelphis marsupialis. The parasitic protozoa used in this study was found and isolated in the intestine of opossums in Pavlova starch-containing medium in Florianópolis, State of Santa Catarina, Brazil, from D. marsupialis and Lutreolina crassicaudata. The strains were cultivated in Diamond medium without maltose and with starch solution, pH 7.5 at 28 degrees C. The specimens were stained by the Giemsa method and Heidenhain's iron hematoxylin. The light microscopy study of the trophozoites revealed the same morphologic characteristics as specimens previously described.

Strategies by which some pathogenic trichomonads integrate diverse signals in the decision-making process.

The interaction between each one of Trichomonas vaginalis and Tritrichomonas foetus with their hosts is a complex process in which components associated to the cell surfaces of both parasites and host epithelial cells, and also to soluble components found in vaginal/urethral secretions, are involved. Either cytoadhesion or the cytotoxicity exerted by parasites to host cells can be dictated by virulence factors such as adhesins, cysteine proteinases, laminin-binding proteins, integrins, integrin-like molecules, a cell detachment factor, a pore-forming protein, and glycosidases among others. How trichomonads manipulate informations from the extracellular medium, transduce such informations, and respond to them by stimulating the activities of some surface molecules and/or releasing enzymes are the aspects concerning trichomonal virulence which are here briefly reviewed and discussed.

Strategies by which some pathogenic trichomonads integrate diverse signals in the decision-marking process

The interaction between each one of Trichomonas vaginalis and Tritrichomonas foetus with their hosts is a complex process in which components associated to the cell surfaces of both parasites and host epithelial cells, and also to soluble components found in vaginal/urethral secretions, are involved. Either cytoadhesion or the cytotoxicity exerted by parasites to host cells can be dictated by virulence factors such as adhesins, cysteine proteinases, laminin-binding proteins, integrins, integrin-like molecules, a cell detachment factor, a pore-forming protein, and glycosidases among others. How trichomonads manipulate informations from the extracellular medium, transduce such informations, and respond to them by stimulating the activities of some surface molecules and/or releasing enzymes are the aspects concerning trichomonal virulence which are here briefly reviewed and discussed.

Pesquisa de Ureaplasma urealyticum pregnant women and the correlation with the presence of Trichomonas sp / Research of Ureaplasma urealyticum pregnant women and the correlation with the presence of Trichomonas sp

Foram feitas pesquisas de Ureaplasma urealyticum em material cervical e de Trichomonas sp no conteúdo vaginal de 74 gestantes. A existência ou näo de relaçäo entre a presença simultânea de Ureaplasma urealyticum e Trichomonas sp foi analisada, uma vez que os dados fornecidos pela literatura internacional säo bastante controvertidos. Trichomonas sp estava presente em 21,5% das amostras positivas para Urealyticum e em 13% das amostras em que a ausência do micoplasma foi constatada. Estatisticamente essas diferenças näo foram significantes impossibilitando inferir qualquer correlaçäo entre os dois achados