Tritrichomonas foetus: Ultrastructure and cytochemistry of endocytosis

Benchimol, Marlene; Cunha-e-Silva, Narcisa L.; Elias, Cezar Antonio; Souza, Wanderley de

doi:10.1016/0014-4894(86)90049-4

Cited by 17 publications

(7 citation statements)

References 13 publications

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“…We previously observed that the alteration of parasite morphology due to iron depletion was followed by a significantly different expression of cytoskeleton-related proteins and proteins involved in cell signalling (de Jesus et al 2007 ). The cell surface of trichomonads exhibits an active endocytic machinery ( Benchimol et al 1986, 19 , 1990 ) and it has been suggested that during pseudocyst formation, the flagella are internalised by a receptor-mediated endocytosis process ( Granger et al 2000 , Pereira-Neves et al 2003 ). In addition, we observed that the sequence of flagellar internalisation was similar to that observed in T. foetus , where the recurrent flagellum is internalised first, followed by the anterior flagella ( Pereira-Neves et al 2003 ).…”

Section: Discussionmentioning

confidence: 99%

Morphologic study of the effect of iron on pseudocyst formation in Trichomonas vaginalis and its interaction with human epithelial cells

Dias-Lopes

Sabóia-Vahia

Margotti

et al. 2017

Mem. Inst. Oswaldo Cruz

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BACKGROUND Trichomonas vaginalis is the aetiological agent of human trichomoniasis, which is one of the most prevalent sexually transmitted diseases in humans. Iron is an important element for the survival of this parasite and the colonisation of the host urogenital tract.OBJECTIVES In this study, we investigated the effects of iron on parasite proliferation in the dynamics of pseudocyst formation and morphologically characterised iron depletion-induced pseudocysts.METHODS We performed structural and ultrastructural analyses using light microscopy, scanning electron microscopy and transmission electron microscopy.FINDINGS It was observed that iron depletion (i) interrupts the proliferation of T. vaginalis, (ii) induces morphological changes in typical multiplicative trophozoites to spherical non-proliferative, non-motile pseudocysts, and (iii) induces the arrest of cell division at different stages of the cell cycle; (iv) iron is the fundamental element for the maintenance of typical trophozoite morphology; (v) pseudocysts induced by iron depletion are viable and reversible forms; and, finally, (vi) we demonstrated that pseudocysts induced by iron depletion are able to interact with human epithelial cells maintaining their spherical forms.MAIN CONCLUSIONS Together, these data suggest that pseudocysts could be induced as a response to iron nutritional stress and could have a potential role in the transmission and infection of T. vaginalis.

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Section: Discussionmentioning

confidence: 99%

Morphologic study of the effect of iron on pseudocyst formation in Trichomonas vaginalis and its interaction with human epithelial cells

Dias-Lopes

Sabóia-Vahia

Margotti

et al. 2017

Mem. Inst. Oswaldo Cruz

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“…This could be explained by the size of mammalian cells, which is many times larger than the parasite, since previous studies have shown that living or dead yeast (Pereira-Neves and Benchimol, 2007) and bacteria (Benchimol and De Souza, 1995; Francioli et al 1983) are promptly ingested by trichomonads. Other cell surface elements might also be involved in cell recognition since some bacterial strains are not ingested by T. vaginalis (Pereira-Neves and Benchimol, unpublished observations) whereas in other cell types, fibronectin, carbohydrates and other cell surface molecules are important factors (Benchimol et al 1986, 1990, 2008; Bonilha et al 1995). Thus, T. vaginalis seems to act differently from amoebae, which are able to ingest epithelial cells regardless of whether they have been previously lysed or not (Martinez-Palomo et al 1985).…”

Section: Discussionmentioning

confidence: 99%

Trichomonas vaginaliskills and eats – evidence for phagocytic activity as a cytopathic effect

Midlej

Benchimol

2009

Parasitology

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This study reports that the cytopathic effect of Trichomonas vaginalis, an important human parasite of the urogenital tract, occurs due to mechanical stress and subsequent phagocytosis of the necrotic cells. The investigation was done using a primary culture of bovine oviduct epithelial cells (BOECs), grown either in monolayers or as floating cells. Trophozoites displaying different virulence levels were co-incubated with BOECs for times varying between 1 min and 48 h. Analyses were performed using videomicroscopy, scanning and transmission electron microscopy, colourimetric assays and cytochemistry. Injury was observed as early as 1 h after incubation, while after 12 h the host cells were severely damaged when a fresh trichomonad isolate was used. Trichomonads attack the host cells by clustering around them. Mechanical stress on the microvilli of the host cells was observed and appeared to induce plasma membrane damage and cell death. After membrane injury and lysis, fragments of the necrotic cells were ingested by trichomonads. Phagocytosis occurred by trichomonads avidly eating large portions of epithelial cells containing the nucleus and other organelles, but living or intact cells were not ingested. Necrotic fragments were rapidly digested in lysosomes, as shown by acid phosphatase and ruthenium red assays where only the BOECs were labelled. The lytic capacity of the trichomonads was more pronounced in host cell suspensions.

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“…The size of internalized particles or structures does not necessarily determine which mechanism predominates, although in mammalian macrophages the contribution of phagocytosis generally increases with increasing particle size (Pratten and Lloyd 1986;Koval et al 1998). A very active endocytic machinery exists at the T. foetus cell surface (Benchimol et al 1981(Benchimol et al , 1986(Benchimol et al , 1990(Benchimol et al , 1992Queiroz et al 1991;Aonso et al 1994Aonso et al , 1997Granger and Warwood 1996;Tachezy et al 1996Tachezy et al , 1998, raising the possibility that the¯agella might be laterally internalized by a process akin to receptor-mediated endocytosis. Hypertonic medium inhibits clathrin-mediated endocytosis in mammalian cells by preventing clathrin from interacting with adaptor proteins (Daukas and Zigmond 1985;Hansen et al 1993); these conditions also inhibited¯a-gellar internalization by T. foetus.…”

Section: Discussionmentioning

confidence: 99%

Transient invagination of flagella by Tritrichomonas foetus

Granger

Warwood

Benchimol³

et al. 2000

Parasitol Res

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We describe an experimental system for the study of rapid and reversible formation of pseudocysts, which are spherical forms that lack a true cyst wall, by Tritrichomonas foetus, a trichomonad parasite of the bovine genitourinary tract. It highlights the dynamics of the plasma membrane and cytoskeleton of this parasite, which is perpetually devoid of any sort of protective cell wall, and can reflect a responsive survival mechanism. We have found that cooling of axenic cultures of T. foetus from their normal 37 degrees C to below about 16 degrees C can trigger pseudocyst formation. The three anterior flagella and the single recurrent flagellum can be fully internalized within 1 3 min at 37 degrees C, with the axonemes and flagellar membranes remaining intact within the cell body. Electron microscopy confirms that the internalized flagella are surrounded by a separate membrane. At 37 degrees C the internalized flagella can resume beating movements and become externalized as quickly as within 10 min. We have begun to elucidate the mechanisms of this unusual phenomenon, characterizing its temperature dependence and exploring the effects of agents that interfere with various aspects of the cytoskeleton, phagocytosis, endocytosis, and exocytosis.

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Tritrichomonas foetus: Ultrastructure and cytochemistry of endocytosis

Cited by 17 publications

References 13 publications

Morphologic study of the effect of iron on pseudocyst formation in Trichomonas vaginalis and its interaction with human epithelial cells

Morphologic study of the effect of iron on pseudocyst formation in Trichomonas vaginalis and its interaction with human epithelial cells

Trichomonas vaginaliskills and eats – evidence for phagocytic activity as a cytopathic effect

Transient invagination of flagella by Tritrichomonas foetus

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