Navegando por Palavras-chave "Metacyclic trypomastigote"

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    Beta-adrenergic antagonist propranolol inhibits mammalian cell lysosome spreading and invasion by Trypanosoma cruzi metacyclic forms
    (Elsevier Science Bv, 2017) Macedo, Silene [UNIFESP]; Ferreira Rodrigues, Joao Paulo [UNIFESP]; Schenkman, Sergio [UNIFESP]; Yoshida, Nobuko [UNIFESP]
    The involvement of beta-adrenergic receptor (beta-AR) in host cell invasion by Trypanosoma cruzi metacyclic trypomastigote (MT) is not known. We examined whether isoproterenol, an agonist of beta-AR, or nonselective beta-blocker propranolol affected MT internalization mediated the stage-specific surface molecule gp82. Treatment of HeLa cells with propranolol significantly inhibited MT invasion whereas isoproterenol had no effect. Propranolol, but not isoproterenol, also inhibited the lysosome spreading required for gp82-dependent MT invasion. The effect of propranolol in inhibiting MT internalization was not due to the prevention of gp82 interaction with beta-AR. It was mainly associated with its ability to impair lysosome spreading. (C) 2017 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.
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    Characterization of a 21 kDa protein from Trypanosoma cruzi associated with mammalian cell invasion
    (Elsevier B.V., 2009-04-01) Silva, Claudio V. da [UNIFESP]; Kawashita, Silvia Y. [UNIFESP]; Probst, Christian M.; Dallagiovanna, Bruno; Cruz, Mario C. [UNIFESP]; Silva, Erika A. da [UNIFESP]; Souto-Padron, Thais C. B. S.; Krieger, Marco A.; Goldenberg, Samuel; Briones, Marcelo R. S. [UNIFESP]; Andrews, Norma W.; Mortara, Renato A. [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Fiocruz MS; Universidade Federal do Rio de Janeiro (UFRJ); Yale Univ
    Trypanosoma cruzi genomic database was screened for hypothetical proteins that showed high probability of being secreted or membrane anchored and thus, likely involved in host-cell invasion. A sequence that codes for a 21 kDa protein that showed high probability of being secreted was selected. After cloning this protein sequence, the results showed that it was a ubiquitous protein and secreted by extracellular amastigotes. the recombinant form (P21-His(6)) adhered to HeLa cells in a dose-dependent manner. Pretreatment of host cells with P21-His(6) inhibited cell invasion by extracellular amastigotes from G and CL strains. On the other hand, when the protein was added to host cells at the same time as amastigotes, an increase in cell invasion was observed. Host-cell pretreatment with P21-His(6) augmented invasion by metacyclic trypomastigotes. Moreover, polyclonal antibody anti-P21 inhibited invasion only by extracellular amastigotes and metacyclic trypomastigotes from G strain. These results suggested that P21 might be involved in T. cruzi cell invasion. We hypothesize that P21 could be secreted in the juxtaposition parasite-host cell and triggers signaling events yet unknown that lead to parasite internalization. (C) 2009 Elsevier Masson SAS. All rights reserved.
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    Isolation and characterisation of genomic and cDNA clones coding for a serine-, alanine-, and proline-rich protein of Trypanosoma cruzi
    (Elsevier B.V., 2001-03-01) Carmo, Mirian Silva do [UNIFESP]; Santos, Marcia Regina Machado dos [UNIFESP]; Cummings, Leda Maria [UNIFESP]; Araya, Jorge Enrique; Yamauchi, Lucy Megumi [UNIFESP]; Yoshida, Nobuko [UNIFESP]; Mortara, Renato Arruda [UNIFESP]; Silveira, José Franco da [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Univ Antofagasta
    We report here the isolation and characterisation of genomic and cDNA clones encoding a Serine-, Alanine-, and Proline-rich protein (SAP) of Trypanosoma cruzi metacyclic trypomastigotes. the deduced peptides translated from these clones were characterised by a high content of residues of alanine, proline, serine, glycine, valine, and threonine distributed in several repeats: P2-4, S2-3, A(2-3), AS, SA, PA, AP, SP, PS, and TP. the repeats are partially homologous to the serine-, alanine-, and proline-containing motifs of Leishmania major and Leishmania mexicana proteophosphoglycans. Genes coding for SAP are part of a polymorphic family whose members are linked to members of gp85/ sialidase and mucin-like gene families. This is consistent with the hypothesis that this genetic organisation could be a means by which T. cruzi co-ordinates the expression of major surface proteins. (C) 2001 Australian Society for Parasitology Inc. Published by Elsevier B.V. All rights reserved.
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    Posttranscriptional mechanisms involved in the control of expression of the stage-specific GP82 surface glycoprotein in Trypanosoma cruzi
    (Elsevier B.V., 2009-02-01) Gentil, Luciana Girotto [UNIFESP]; Cordero, Esteban Mauricio [UNIFESP]; Carmo, Mirian Silva do [UNIFESP]; Machado dos Santos, Marcia Regina [UNIFESP]; Silveira, Jose Franco da [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Trypanosoma cruzi metacyclic trypomastigotes express the developmentally regulated GP82 glycoprotein, which is implicated in host cell invasion. Although GP82 mRNA and protein are not present and the mRNAs barely detectable in epimastigotes, nuclear run-on analysis showed that it is transcribed in both stages. This result indicates that accumulation of transcripts in metacyclic forms is not due to increased transcription of the GP82 gene. To investigate whether mRNA stability may be responsible for the differences in the steady-state levels of this mRNA, parasites were treated with actinomycin D or cycloheximide. When treated with actinomycin D, the half-lives estimated for GP82 transcripts were about 6 h ill metacyclic trypmastigotes and 0.5 h in epimastigotes. in the presence of cycloheximide, the levels of GP82 mRNA decayed slightly after 8 h in metacyclic trypomastigotes, whereas in epimastigotes the levels of this mRNA increased. This effect suggests a stabilizing mechanism acting in metacyclic trypomastigotes and a destabilizing mechanism in epimastigotes which Could be mediated by an element present in the 3'-UTR of the transcripts. Consistent with this finding, northern blot analysis showed that GP82 mRNAs were mobilized to polysomes and consequently translated, but only in metacyclic trypomastigotes. (C) 2008 Elsevier B.V. All rights reserved.