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Actions of a Proline Analogue, L-Thiazolidine-4-Carboxylic Acid (T4C), on Trypanosoma cruzi  [PDF]
Anahí Magdaleno, Il-Young Ahn, Lisvane Silva Paes, Ariel M. Silber
PLOS ONE , 2009, DOI: 10.1371/journal.pone.0004534
Abstract: It is well established that L-proline has several roles in the biology of trypanosomatids. In Trypanosoma cruzi, the etiological agent of Chagas' disease, this amino acid is involved in energy metabolism, differentiation processes and resistance to osmotic stress. In this study, we analyzed the effects of interfering with L-proline metabolism on the viability and on other aspects of the T. cruzi life cycle using the proline analogue L- thiazolidine-4-carboxylic acid (T4C). The growth of epimastigotes was evaluated using different concentrations of T4C in standard culture conditions and at high temperature or acidic pH. We also evaluated possible interactions of this analogue with stress conditions such as those produced by nutrient starvation and oxidative stress. T4C showed a dose-response effect on epimastigote growth (IC50 = 0.89±0.02 mM at 28°C), and the inhibitory effect of this analogue was synergistic (p<0.05) with temperature (0.54±0.01 mM at 37°C). T4C significantly diminished parasite survival (p<0.05) in combination with nutrient starvation and oxidative stress conditions. Pre-incubation of the parasites with L-proline resulted in a protective effect against oxidative stress, but this was not seen in the presence of the drug. Finally, the trypomastigote bursting from infected mammalian cells was evaluated and found to be inhibited by up to 56% when cells were treated with non-toxic concentrations of T4C (between 1 and 10 mM). All these data together suggest that T4C could be an interesting therapeutic drug if combined with others that affect, for example, oxidative stress. The data also support the participation of proline metabolism in the resistance to oxidative stress.
The cell surface of Trypanosoma cruzi
Souza, Wanderley de;Souto-Padrón, Thais;
Memórias do Instituto Oswaldo Cruz , 1984, DOI: 10.1590/S0074-02761984000500003
Abstract: the cell surface of trypanosomatids is formed by the plasma membrane and a layer of sub-pellicular microtubules which are connected to the plasma membrane. the plasma membrane is composed by proteins, lipids and carbohydrates which form the glycocalix. in this paper we will review briefly aspects related to the organization of the cell surface of trypanosoma cruzi.
Trypanosoma cruzi: circulating antigens
Bongertz, V.;Hungerer, Klaus-Dieter;Galv?o-Castro, Bernardo;
Memórias do Instituto Oswaldo Cruz , 1981, DOI: 10.1590/S0074-02761981000100008
Abstract: circulating antigens were detected in sera of mice experimentally infected with a high close of trypanosoma cruzi by reaction with sera from chronically infected mice. the immunodiffusion reaction between homologous acute and chronic sera produced four precipitation lines. by reaction with chronic mouse serum, circulating antingens were detected in sera from heavily infected hamsters, dogs, rabbits and in sera from chagasic patients. a reaction was also found in urine from acutely infected mice and dogs. trypanosoma cruzi exoantigen was detected in trypanosome culture medium and in the supernatant of infected cell cultures. attempts to isolate the antigens are described.
Structural organization of Trypanosoma cruzi
Souza, Wanderley de;
Memórias do Instituto Oswaldo Cruz , 2009, DOI: 10.1590/S0074-02762009000900014
Abstract: since the initial description of trypanosoma cruzi by carlos chagas in 1909, several research groups have used different microscopic techniques to obtain detailed information about the various developmental stages found in the life cycle of this intracellular parasite. this review describes the present knowledge on the organization of the most important structures and organelles found in the protozoan, such as the cell surface, flagellum, cytoskeleton, kinetoplast-mitochondrion complex, glycosome, acidocalcisome, contractile vacuole, lipid inclusions, the secretory pathway, endocytic pathway and the nucleus.
Endothelial Transmigration by Trypanosoma cruzi  [PDF]
Bria M. Coates, David P. Sullivan, Ming Y. Makanji, Nga Y. Du, Cheryl L. Olson, William A. Muller, David M. Engman, Conrad L. Epting
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0081187
Abstract: Chagas heart disease, the leading cause of heart failure in Latin America, results from infection with the parasite Trypanosoma cruzi. Although T. cruzi disseminates intravascularly, how the parasite contends with the endothelial barrier to escape the bloodstream and infect tissues has not been described. Understanding the interaction between T. cruzi and the vascular endothelium, likely a key step in parasite dissemination, could inform future therapies to interrupt disease pathogenesis. We adapted systems useful in the study of leukocyte transmigration to investigate both the occurrence of parasite transmigration and its determinants in vitro. Here we provide the first evidence that T. cruzi can rapidly migrate across endothelial cells by a mechanism that is distinct from productive infection and does not disrupt monolayer integrity or alter permeability. Our results show that this process is facilitated by a known modulator of cellular infection and vascular permeability, bradykinin, and can be augmented by the chemokine CCL2. These represent novel findings in our understanding of parasite dissemination, and may help identify new therapeutic strategies to limit the dissemination of the parasite.
Plasminogen interaction with Trypanosoma cruzi
Almeida, Laura;Vanegas, Gilmer;Calcagno, Marina;Concepción, Juan Luis;Avilan, Luisana;
Memórias do Instituto Oswaldo Cruz , 2004, DOI: 10.1590/S0074-02762004000100011
Abstract: the ability of trypanosoma cruzi to interact with plasminogen, the zimogenic form of the blood serin protease plasmin, was examined. immunohistochemistry studies revealed that both forms, epimastigotes and metacyclic trypomastigotes, were able to fix plasminogen in a lysine dependant manner. this interaction was corroborated by plasminogen activation studies. both forms of the parasite enhanced the plasminogen activation by tissue-type plasminogen activator.the maximal enhancements obtained were 15-fold and 3.4-fold with epimastigotes and metacyclic trypomastigotes, respectively, as compared to plasminogen activation in absence of cells. ligand-blotting analysis of proteins extracted with triton x-114 from a microsomal fraction of epimastigotes revealed at least five soluble proteins and one hydrophobic protein able to bind plasminogen.
Plasminogen interaction with Trypanosoma cruzi  [cached]
Almeida Laura,Vanegas Gilmer,Calcagno Marina,Concepción Juan Luis
Memórias do Instituto Oswaldo Cruz , 2004,
Abstract: The ability of Trypanosoma cruzi to interact with plasminogen, the zimogenic form of the blood serin protease plasmin, was examined. Immunohistochemistry studies revealed that both forms, epimastigotes and metacyclic trypomastigotes, were able to fix plasminogen in a lysine dependant manner. This interaction was corroborated by plasminogen activation studies. Both forms of the parasite enhanced the plasminogen activation by tissue-type plasminogen activator.The maximal enhancements obtained were 15-fold and 3.4-fold with epimastigotes and metacyclic trypomastigotes, respectively, as compared to plasminogen activation in absence of cells. Ligand-blotting analysis of proteins extracted with Triton X-114 from a microsomal fraction of epimastigotes revealed at least five soluble proteins and one hydrophobic protein able to bind plasminogen.
Profiling the Trypanosoma cruzi Phosphoproteome  [PDF]
Fabricio K. Marchini, Lyris M. F. de Godoy, Rita C. P. Rampazzo, Daniela P. Pavoni, Christian M. Probst, Florian Gnad, Matthias Mann, Marco A. Krieger
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0025381
Abstract: Protein phosphorylation is a reversible post-translational modification essential for the regulation of several signal transduction pathways and biological processes in the living cell. Therefore, the identification of protein phosphorylation sites is crucial to understand cell signaling control at the molecular level. Based on mass spectrometry, recent studies have reported the large-scale mapping of phosphorylation sites in various eukaryotes and prokaryotes. However, little is known about the impact of phosphorylation in protozoan parasites. To in depth characterize the phosphoproteome of Trypanosoma cruzi, a parasite of the Kinetoplastida class, protein samples from cells at different phases of the metacyclogenesis – differentiation process of the parasites from non-infective epimastigotes to infective metacyclic trypomastigotes - were enriched for phosphopeptides using TiO2 chromatography and analyzed on an LTQ-Orbitrap mass spectrometer. In total, 1,671 proteins were identified, including 753 phosphoproteins, containing a total of 2,572 phosphorylation sites. The distribution of phosphorylated residues was 2,162 (84.1%) on serine, 384 (14.9%) on threonine and 26 (1.0%) on tyrosine. Here, we also report several consensus phosphorylation sequence motifs and as some of these conserved groups have enriched biological functions, we can infer the regulation by protein kinases of this functions. To our knowledge, our phosphoproteome is the most comprehensive dataset identified until now for Kinetoplastida species. Here we also were able to extract biological information and infer groups of sites phosphorylated by the same protein kinase. To make our data accessible to the scientific community, we uploaded our study to the data repositories PHOSIDA, Proteome Commons and TriTrypDB enabling researchers to access information about the phosphorylation sites identified here.
Biological characterization of Trypanosoma cruzi strains
Martínez-Díaz, Rafael A;Escario, José A;Nogal-Ruiz, Juan J;Gómez-Barrio, Alicia;
Memórias do Instituto Oswaldo Cruz , 2001, DOI: 10.1590/S0074-02762001000100006
Abstract: biological parameters of five trypanosoma cruzi strains from different sources were determined in order to know the laboratory behaviour of natural populations. the parameters evaluated were growth kinetics of epimastigotes, differentiation into metacyclic forms, infectivity in mammalian cells grown in vitro and parasite susceptibility to nifurtimox, benznidazole and gentian violet. differences in transformation to metacyclic, in the percentage of infected cells as well as in the number of amastigotes per cell were observed among the strains. regarding to pharmacological assays, y strain was the most sensitive to the three assayed compounds. these data demonstrate the heterogeneity of natural populations of t. cruzi, the only responsible of infection in humans.
Biological characterization of Trypanosoma cruzi strains  [cached]
Martínez-Díaz Rafael A,Escario José A,Nogal-Ruiz Juan J,Gómez-Barrio Alicia
Memórias do Instituto Oswaldo Cruz , 2001,
Abstract: Biological parameters of five Trypanosoma cruzi strains from different sources were determined in order to know the laboratory behaviour of natural populations. The parameters evaluated were growth kinetics of epimastigotes, differentiation into metacyclic forms, infectivity in mammalian cells grown in vitro and parasite susceptibility to nifurtimox, benznidazole and gentian violet. Differences in transformation to metacyclic, in the percentage of infected cells as well as in the number of amastigotes per cell were observed among the strains. Regarding to pharmacological assays, Y strain was the most sensitive to the three assayed compounds. These data demonstrate the heterogeneity of natural populations of T. cruzi, the only responsible of infection in humans.
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