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Journal ArticleDOI

Trypanosoma cruzi: characterization of an intracellular epimastigote-like form.

01 Aug 1999-Experimental Parasitology (Academic Press)-Vol. 92, Iss: 4, pp 263-274
TL;DR: It is proposed that the epimastigote-like forms are an obligatory transitional stage in the transformation of amastigotes to trypomastsigotes with a variable time of permanency in the host cell cytoplasm depending on environmental conditions.
About: This article is published in Experimental Parasitology.The article was published on 1999-08-01. It has received 83 citations till now. The article focuses on the topics: Host cell cytoplasm & Trypanosoma cruzi.
Citations
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Journal ArticleDOI
TL;DR: A revised life cycle of Trypanosoma cruzi is presented, influenced by recent findings and specific questions that remain unresolved.

370 citations


Cites background from "Trypanosoma cruzi: characterization..."

  • ...Other studies have also shown that rate of metacyclogenesis in culture is exquisitely sensitive to the availability of simple sugars ( Adroher et al., 1988; Homsy et al., 1989; Krassner et al., 1990)....

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  • ...Much more research is required to determine if this is indeed the case; however, recent reports of shared stage-speci®c epitopes and biochemical properties between extracellular and intracellular epimastigotes do lend support to this view (Faucher et al., 1995; Almeida-de-Faria et al., 1999)....

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Journal ArticleDOI
TL;DR: The SELEX technique was used to evolve nuclease-resistant RNA ligands (aptamer = to fit) that bind with affinities of 40-400 nm to parasite receptors for the host cell matrix molecules laminin, fibronectin, thrombospondin, and heparan sulfate.

157 citations

Journal ArticleDOI
TL;DR: The in vitro growth inhibition activity of new thiosemicarbazone derivatives against the protozoan parasite Trypanosoma cruzi, the causative agent of American trypanosomiasis, is described and these compounds are among the most potent 5-nitrofuryl derivatives tested against this parasite.

117 citations

Journal ArticleDOI
TL;DR: Docking studies were carried out in order to investigate the binding pattern of these compounds for the T. cruzi cruzain (TCC) protein, and these showed a significant correlation with experimental data.

98 citations

Journal ArticleDOI
TL;DR: It was found that differentiation of intracellular epimastigotes and trypomastigote bursting were proline concentration dependent, and there was evidence for a high turnover for the l‐proline pool in that parasite stage.
Abstract: Summary Using as the host cell, a proline-requiring mutant of Chinese hamster ovary cell (CHO-K1), it was possible to arrest the differentiation of amastigote forms of Trypanosoma cruzi at the intermediate intracellular epimastigote-like stage. Complete differentiation to the trypomastigote stage was obtained by addition of L -proline to the medium. This effect was more pro- nounced using the T. cruzi CL-14 clone that differen- tiates fully at 33 ∞ ∞ ∞ C (permissive temperature) and poorly at 37 ∞ C (restrictive temperature). A synchro- nous differentiation of T. cruzi inside the host-cell is then possible by temperature switching in the pres- ence of proline. It was found that differentiation of intracellular epimastigotes and trypomastigote burst- ing were proline concentration dependent. The intra- cellular concentration of proline was measured as well as the transport capacity of proline by each stage of the parasite. Amastigotes have the highest concen- tration of free proline (8.09 ± 1.46 mM) when com- pared to trypomastigotes (3.81 ± 1.55) or intracellular epimastigote-like forms (0.45 ± 0.06 mM). In spite of having the lowest content of intracellular free proline, intracellular epimastigotes maintained the highest levels of L -proline transport compared to trypomas- tigotes and intracellular amastigotes, providing evi- dence for a high turnover for the L -proline pool in that parasite stage. This is the first report to establish a relationship between proline concentration and intra- cellular differentiation of Trypanosoma cruzi in the mammalian host.

94 citations


Cites background or methods or result from "Trypanosoma cruzi: characterization..."

  • ...…epimastigote-like forms are an obligatory intermediate step in the differentiation of amastigotes to trypomastigotes, confirming previous claims (Almeida-de-Faria et al., 1999); (ii) L-proline is essential for the differentiation of the intracellular epimastigote-like forms to trypomastigotes;…...

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  • ..., 1989) and intracellular epimastigotes (Almeida-de-Faria et al., 1999)....

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  • ...Intracellular forms and trypomastigotes were obtained by infection of CHOK1 cells with trypomastigotes, as described (Almeida-de-Faria et al., 1999)....

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  • ...After 30 min, cells were incubated with a polyclonal antibody against T. cruzi (1 : 100) followed by FITClabelled goat anti-rabbit IgG, as described (Almeida-de-Faria et al., 1999)....

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  • ...cruzi (1 : 100) followed by FITClabelled goat anti-rabbit IgG, as described (Almeida-de-Faria et al., 1999)....

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References
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Journal ArticleDOI
TL;DR: Salivarian trypanosomes were separated from infected blood by adsorbing the particulate blood components on to DEAE-cellulose columns and eluting the trypanOSomes, confirming previous observations, cyclically transmitted isolations behaving similarly to those which were mechanically transmitted.

1,374 citations

Journal ArticleDOI
TL;DR: Progression through cytokinesis, (zoid formation) while mitosis is compromised, suggests that the dependency relationships leading to the classical cell cycle check points may be altered in trypanosomes, to take account of the need to segregate two unit genomes (nuclear and mitochondrial) in this cell.
Abstract: Trypanosoma brucei has a precisely ordered microtubule cytoskeleton whose morphogenesis is central to cell cycle events such as organelle positioning, segregation, mitosis, and cytokinesis. We have defined microtubule polarity and show the + ends of the cortical microtubules to be at the posterior end of the cell. Measurements of organelle positions through the cell cycle reveal a high degree of coordinate movement and a relationship with overall cell extension. Quantitative analysis of the segregation of the replicated mitochondrial genome (the kinetoplast) by the flagellar basal bodies identifies a new G2 cell cycle event marker. The subsequent mitosis then positions one "daughter" nucleus into the gap between the segregated basal bodies/kinetoplasts. The anterior daughter nucleus maintains its position relative to the anterior of the cell, suggesting an effective yet cryptic nuclear positioning mechanism. Inhibition of microtubule dynamics by rhizoxin results in a phenomenon whereby cells, which have segregated their kinetoplasts yet are compromised in mitosis, cleave into a nucleated portion and a flagellated, anucleate, cytoplast. We term these cytoplasts "zoids" and show that they contain the posterior (new) flagellum and associated basal-body/kinetoplast complex. Examination of zoids suggests a role for the flagellum attachment zone (FAZ) in defining the position for the axis of cleavage in trypanosomes. Progression through cytokinesis, (zoid formation) while mitosis is compromised, suggests that the dependency relationships leading to the classical cell cycle check points may be altered in trypanosomes, to take account of the need to segregate two unit genomes (nuclear and mitochondrial) in this cell.

317 citations

Journal ArticleDOI
TL;DR: Electron microscopic observations indicated the uptake by phagocytosis of both forms into mouse peritoneal macrophages and of trypomastigotes and transition forms into other cultured cell types, indicating that protease-sensitive structures on the macrophage plasma membrane mediate ingestion.
Abstract: The mode of entry and intracellular fate of epimastigotes and trypomastigotes of Trypanosoma cruzi in cultured cells was studied. Electron microscopic observations indicated the uptake by phagocytosis of both forms into mouse peritoneal macrophages and of trypomastigotes and transition forms into other cultured cell types. In each instance the organisms were initially surrounded by a plasma membrane-derived phagosome. Trypsin and chymotrypsin treatment of the macrophages completely abolished attachment and ingestion of both forms, indicating that protease-sensitive structures on the macrophage plasma membrane mediate ingestion. The macrophage Fc or C3b receptors were not essential for uptake of T. cruzi in the conditions used. Cytochalasin B inhibited ingestion but not the attachment of both forms by macrophages. Epimastigotes were not taken up by HeLa, L cells, and calf embryo fibroblasts. In macrophages, epimastigotes were killed and digested within phagolysosomes. In contrast, trypomastigotes and transition forms escaped from the phagocytic vacuole and then multiplied in the cytoplasmic matrix. Amastigotes released from infected cells exhibited properties similar to those of trypomastigotes and were able to enter all cell types studied and multiply intracellularly.

290 citations

Book ChapterDOI
TL;DR: This chapter reviews some aspects of the cell biology of Trypanosoma cruzi, giving emphasis to those aspects related to the ultrastructure of pathogenic protozoa.
Abstract: Publisher Summary Among the protozoa of the Trypanosomatidae family, a large number of species represent agents of diseases, such as Chagas' disease. This chapter reviews some aspects of the cell biology of Trypanosoma cruzi, giving emphasis to those aspects related to the ultrastructure of pathogenic protozoa. Protozoa of the Trypanosomatidae family show, during their, life cycle, several forms which can be easily identified by light microscopy in Giemsa-stained preparations. The chapter also explains the life cycle of T. cruzi. In the life cycle of T. cruzi, there are forms which are able to divide. There is one form, considered to be highly differentiated and responsible for the infectivity of these protozoa, which does not divide. It is highlighted that the trypomastigote form can transform into a rounded form which possesses a free flagellum. This form, which appears in the stomach, is able to transform into either short epimastigotes that start a process of multiplication in the intestinum or into long epimastigotes which move to the more posterior region of the digestive tract of the bug. Cell surface is also emphasized in the chapter.

274 citations