The C-terminal region of Trypanosoma cruzi MASPs is antigenic and secreted via exovesicles.

Trypanosoma cruzi is the etiological agent of Chagas disease, a neglected and emerging tropical disease, endemic to South America and present in non-endemic regions due to human migration. The MASP multigene family is specific to T. cruzi, accounting for 6% of the parasite's genome and plays a key role in immune evasion. A common feature of MASPs is the presence of two conserved regions: an N-terminal region codifying for signal peptide and a C-terminal (C-term) region, which potentially acts as GPI-addition signal peptide. Our aim was the analysis of the presence of an immune response against the MASP C-term region. We found that this region is highly conserved, released via exovesicles (EVs) and has an associated immune response as revealed by epitope affinity mapping, IFA and inhibition of the complement lysis assays. We also demonstrate the presence of a fast IgM response in Balb/c mice infected with T. cruzi. Our results reveal the presence of non-canonical secreted peptides in EVs, which can subsequently be exposed to the immune system with a potential role in evading immune system targets in the parasite

First precise U-Pb baddeleyite ages of 1500 Ma mafic dykes from the Sao Francisco Craton, Brazil, and tectonic implications

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The Sao Francisco Craton (SFC) is an Archaean-Proterozoic craton that hosts a significant number of mafic intrusions. Previous attempts to date the igneous emplacement of these rocks are limited to a few poor precision Rb-Sr and Sm-Nd isochrons. Here, dykes from the Curaca belt, in the northeastern portion of the craton, as well as from the Chapada Diamantina region in the central part, were dated using U-Pb on baddeleyite (ID-TIMS). These dykes yielded similar baddeleyite U-Pb ages of 1506.7 +/- 6.9 Ma (Curaca) and 1501.0 +/- 9.1 Ma (Chapada), with converging trends indicating a possible magmatic centre located near the western margin of the Sao Francisco Craton. The two dyke swarms are subalkaline, and have light rare earth enriched chondrite-normalized patterns but the Curaca dykes have lower Mg-number and higher abundances of most incompatible trace elements than the Chapada dykes. Geochemical modelling and trace element ratios suggest that the two dyke swarms had different petrogenesis, with the Chapada dykes being derived from more depleted mantle sources and the Curaca dykes from enriched sources, however the mantle sources of both dyke swarms appear to have had contributions from an enriched plume. Current geochronological and palaeomagnetic data suggest a coherent Sao Francisco-Congo block from at least the late Mesoproterozoic until the opening of the South Atlantic (ca. 130 Ma ago). The discovery of ca. 1500 Ma intrusions in the Sao Francisco Craton is a major step forward to a more complete barcode record for the SFC-Congo Craton, which can be used in future palaeo-continental reconstructions. (C) 2012 Elsevier B.V. All rights reserved.174SI144156project "Reconstruction of Supercontinents Back to 2.7 Ga Using the Large Igneous Province (LIP) Record: with Implications for Mineral Deposit Targeting, Hydrocarbon Resource Exploration and Earth System Evolution".Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CNPq [302590/2008-0

A panoramic view of the immune response to Trypanosoma cruzi infection

Chagas disease is a complex disorder in which the immunological response developed by the host plays a fundamental role, not only in the clearance of the parasite but also in the inflammatory status observed in specific affected tissues. Chagas disease has two phases, acute and chronic, the latter being established in those cases where treatment with currently available anti-parasitic drugs (Nifurtimox and Benznidazole) is either not applied or not effective. During the chronic phase, the disease may remain without any detectable symptoms for several decades, or progress toward cardiac, digestive, neurological forms, or even a combination of these alterations. The immune response developed in all of these conditions is flowery and comprises humoral and cellular components; however the clearance of the parasite is incomplete due to the multiple mechanisms that T. cruzi deploys in order to perpetuate itself within the host.Here, we make an extensive review of T. cruzi-host immune response interactions with special attention on human models, and also referring to the particular clinical scenario of etiological treatment in Chagas disease.Fil: Acevedo, Gonzalo Raúl. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Girard, Magalí Celeste. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Gomez, Karina Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; Argentin